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Torii T. Abnormal expression of Tau in damaged oligodendrocytes of HLD1 mice. Neural Regen Res 2024; 19:1405-1406. [PMID: 38051869 PMCID: PMC10883510 DOI: 10.4103/1673-5374.387983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 09/28/2023] [Indexed: 12/07/2023] Open
Affiliation(s)
- Tomohiro Torii
- Laboratory of Ion Channel Pathophysiology, Graduate School of Brain Science, Doshisha University, Kyotanabe-shi, Kyoto, Japan; Center for Research in Neurodegenerative Disease, Doshisha University, Kyotanabe-shi, Kyoto, Japan
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2
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Zhu Y, Cho K, Lacin H, Zhu Y, DiPaola JT, Wilson BA, Patti GJ, Skeath JB. Loss of dihydroceramide desaturase drives neurodegeneration by disrupting endoplasmic reticulum and lipid droplet homeostasis in glial cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.01.573836. [PMID: 38260379 PMCID: PMC10802327 DOI: 10.1101/2024.01.01.573836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Dihydroceramide desaturases convert dihydroceramides to ceramides, the precursors of all complex sphingolipids. Reduction of DEGS1 dihydroceramide desaturase function causes pediatric neurodegenerative disorder hypomyelinating leukodystrophy-18 (HLD-18). We discovered that infertile crescent (ifc), the Drosophila DEGS1 homolog, is expressed primarily in glial cells to promote CNS development by guarding against neurodegeneration. Loss of ifc causes massive dihydroceramide accumulation and severe morphological defects in cortex glia, including endoplasmic reticulum (ER) expansion, failure of neuronal ensheathment, and lipid droplet depletion. RNAi knockdown of the upstream ceramide synthase schlank in glia of ifc mutants rescues ER expansion, suggesting dihydroceramide accumulation in the ER drives this phenotype. RNAi knockdown of ifc in glia but not neurons drives neuronal cell death, suggesting that ifc function in glia promotes neuronal survival. Our work identifies glia as the primary site of disease progression in HLD-18 and may inform on juvenile forms of ALS, which also feature elevated dihydroceramide levels.
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Affiliation(s)
- Yuqing Zhu
- Department of Genetics, Washington University School of Medicine, 4523 Clayton Avenue, St. Louis, MO 63110, USA
| | - Kevin Cho
- Department of Chemistry, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130, USA
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
- Center for Mass Spectrometry and Metabolic Tracing, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130, USA
| | - Haluk Lacin
- Division of Biological and Biomedical Systems, University of Missouri-Kansas City, Kansas City, MO 64110, USA
| | - Yi Zhu
- Department of Genetics, Washington University School of Medicine, 4523 Clayton Avenue, St. Louis, MO 63110, USA
| | - Jose T DiPaola
- Department of Genetics, Washington University School of Medicine, 4523 Clayton Avenue, St. Louis, MO 63110, USA
| | - Beth A Wilson
- Department of Genetics, Washington University School of Medicine, 4523 Clayton Avenue, St. Louis, MO 63110, USA
| | - Gary J Patti
- Department of Chemistry, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130, USA
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
- Center for Mass Spectrometry and Metabolic Tracing, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130, USA
| | - James B Skeath
- Department of Genetics, Washington University School of Medicine, 4523 Clayton Avenue, St. Louis, MO 63110, USA
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3
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Serrano PDL, Rodrigues TDPV, Pinto LD, Pereira IC, Farias IB, Cavalheiro RBR, Mendes PM, Peixoto KO, Barile JP, Seneor DD, Correa Silva EG, Oliveira ASB, Pinto WBVDR, Sgobbi P. Assessing Chitinases and Neurofilament Light Chain as Biomarkers for Adult-Onset Leukodystrophies. Curr Issues Mol Biol 2024; 46:4309-4323. [PMID: 38785530 PMCID: PMC11120026 DOI: 10.3390/cimb46050262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 04/19/2024] [Accepted: 04/28/2024] [Indexed: 05/25/2024] Open
Abstract
Leukodystrophies represent a large and complex group of inherited disorders affecting the white matter of the central nervous system. Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is a rare leukodystrophy which still needs the proper identification of diagnostic, prognostic, and monitoring biomarkers. The aim of this study was to determine the diagnostic and prognostic value of chitinases and neurofilament light chain as biomarkers for ALSP. A cross-sectional study was performed to analyze cerebrospinal fluid levels of chitinases (chitotriosidase and chitinase 3-like 2) and neurofilament light chain in five different groups: (i) normal health individuals; (ii) patients with definitive diagnosis of ALSP and genetic confirmation; (iii) asymptomatic patients with CSF1R variants; (iv) patients with other adult-onset leukodystrophies; and (v) patients with amyotrophic lateral sclerosis (external control group). Chitinase levels showed a statistical correlation with clinical assessment parameters in ALSP patients. Chitinase levels were also distinct between ALSP and the other leukodystrophies. Significant differences were noted in the levels of chitinases and neurofilament light chain comparing symptomatic (ALSP) and asymptomatic individuals with CSF1R variants. This study is the first to establish chitinases as a potential biomarker for ALSP and confirms neurofilament light chain as a good biomarker for primary microgliopathies.
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Affiliation(s)
- Paulo de Lima Serrano
- PSEG Centro de Pesquisa Clínica, São Paulo 04038-002, SP, Brazil; (P.d.L.S.); (T.d.P.V.R.); (L.D.P.); (I.C.P.); (E.G.C.S.)
- Department of Neurology and Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo 04039-060, SP, Brazil; (I.B.F.); (R.B.R.C.); (P.M.M.); (K.O.P.); (J.P.B.); (D.D.S.); (A.S.B.O.); (W.B.V.d.R.P.)
| | | | - Leslyê Donato Pinto
- PSEG Centro de Pesquisa Clínica, São Paulo 04038-002, SP, Brazil; (P.d.L.S.); (T.d.P.V.R.); (L.D.P.); (I.C.P.); (E.G.C.S.)
| | - Indiara Correia Pereira
- PSEG Centro de Pesquisa Clínica, São Paulo 04038-002, SP, Brazil; (P.d.L.S.); (T.d.P.V.R.); (L.D.P.); (I.C.P.); (E.G.C.S.)
| | - Igor Braga Farias
- Department of Neurology and Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo 04039-060, SP, Brazil; (I.B.F.); (R.B.R.C.); (P.M.M.); (K.O.P.); (J.P.B.); (D.D.S.); (A.S.B.O.); (W.B.V.d.R.P.)
| | - Renan Brandão Rambaldi Cavalheiro
- Department of Neurology and Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo 04039-060, SP, Brazil; (I.B.F.); (R.B.R.C.); (P.M.M.); (K.O.P.); (J.P.B.); (D.D.S.); (A.S.B.O.); (W.B.V.d.R.P.)
| | - Patrícia Marques Mendes
- Department of Neurology and Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo 04039-060, SP, Brazil; (I.B.F.); (R.B.R.C.); (P.M.M.); (K.O.P.); (J.P.B.); (D.D.S.); (A.S.B.O.); (W.B.V.d.R.P.)
| | - Kaliny Oliveira Peixoto
- Department of Neurology and Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo 04039-060, SP, Brazil; (I.B.F.); (R.B.R.C.); (P.M.M.); (K.O.P.); (J.P.B.); (D.D.S.); (A.S.B.O.); (W.B.V.d.R.P.)
| | - João Paulo Barile
- Department of Neurology and Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo 04039-060, SP, Brazil; (I.B.F.); (R.B.R.C.); (P.M.M.); (K.O.P.); (J.P.B.); (D.D.S.); (A.S.B.O.); (W.B.V.d.R.P.)
| | - Daniel Delgado Seneor
- Department of Neurology and Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo 04039-060, SP, Brazil; (I.B.F.); (R.B.R.C.); (P.M.M.); (K.O.P.); (J.P.B.); (D.D.S.); (A.S.B.O.); (W.B.V.d.R.P.)
| | | | - Acary Souza Bulle Oliveira
- Department of Neurology and Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo 04039-060, SP, Brazil; (I.B.F.); (R.B.R.C.); (P.M.M.); (K.O.P.); (J.P.B.); (D.D.S.); (A.S.B.O.); (W.B.V.d.R.P.)
| | - Wladimir Bocca Vieira de Rezende Pinto
- Department of Neurology and Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo 04039-060, SP, Brazil; (I.B.F.); (R.B.R.C.); (P.M.M.); (K.O.P.); (J.P.B.); (D.D.S.); (A.S.B.O.); (W.B.V.d.R.P.)
| | - Paulo Sgobbi
- PSEG Centro de Pesquisa Clínica, São Paulo 04038-002, SP, Brazil; (P.d.L.S.); (T.d.P.V.R.); (L.D.P.); (I.C.P.); (E.G.C.S.)
- Department of Neurology and Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo 04039-060, SP, Brazil; (I.B.F.); (R.B.R.C.); (P.M.M.); (K.O.P.); (J.P.B.); (D.D.S.); (A.S.B.O.); (W.B.V.d.R.P.)
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4
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Rey F, Esposito L, Maghraby E, Mauri A, Berardo C, Bonaventura E, Tonduti D, Carelli S, Cereda C. Role of epigenetics and alterations in RNA metabolism in leukodystrophies. WILEY INTERDISCIPLINARY REVIEWS. RNA 2024; 15:e1854. [PMID: 38831585 DOI: 10.1002/wrna.1854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 04/24/2024] [Accepted: 04/25/2024] [Indexed: 06/05/2024]
Abstract
Leukodystrophies are a class of rare heterogeneous disorders which affect the white matter of the brain, ultimately leading to a disruption in brain development and a damaging effect on cognitive, motor and social-communicative development. These disorders present a great clinical heterogeneity, along with a phenotypic overlap and this could be partially due to contributions from environmental stimuli. It is in this context that there is a great need to investigate what other factors may contribute to both disease insurgence and phenotypical heterogeneity, and novel evidence are raising the attention toward the study of epigenetics and transcription mechanisms that can influence the disease phenotype beyond genetics. Modulation in the epigenetics machinery including histone modifications, DNA methylation and non-coding RNAs dysregulation, could be crucial players in the development of these disorders, and moreover an aberrant RNA maturation process has been linked to leukodystrophies. Here, we provide an overview of these mechanisms hoping to supply a closer step toward the analysis of leukodystrophies not only as genetically determined but also with an added level of complexity where epigenetic dysregulation is of key relevance. This article is categorized under: Regulatory RNAs/RNAi/Riboswitches > Regulatory RNA RNA in Disease and Development > RNA in Disease RNA in Disease and Development > RNA in Development.
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Affiliation(s)
- Federica Rey
- Pediatric Clinical Research Center "Romeo ed Enrica Invernizzi," Department of Biomedical and Clinical Sciences, University of Milano, Milan, Italy
- Center of Functional Genomics and Rare Diseases, Department of Pediatrics, Buzzi Children's Hospital, Milan, Italy
| | - Letizia Esposito
- Pediatric Clinical Research Center "Romeo ed Enrica Invernizzi," Department of Biomedical and Clinical Sciences, University of Milano, Milan, Italy
- Center of Functional Genomics and Rare Diseases, Department of Pediatrics, Buzzi Children's Hospital, Milan, Italy
| | - Erika Maghraby
- Center of Functional Genomics and Rare Diseases, Department of Pediatrics, Buzzi Children's Hospital, Milan, Italy
- Department of Biology and Biotechnology "L. Spallanzani" (DBB), University of Pavia, Pavia, Italy
| | - Alessia Mauri
- Pediatric Clinical Research Center "Romeo ed Enrica Invernizzi," Department of Biomedical and Clinical Sciences, University of Milano, Milan, Italy
- Center of Functional Genomics and Rare Diseases, Department of Pediatrics, Buzzi Children's Hospital, Milan, Italy
| | - Clarissa Berardo
- Pediatric Clinical Research Center "Romeo ed Enrica Invernizzi," Department of Biomedical and Clinical Sciences, University of Milano, Milan, Italy
- Center of Functional Genomics and Rare Diseases, Department of Pediatrics, Buzzi Children's Hospital, Milan, Italy
| | - Eleonora Bonaventura
- Unit of Pediatric Neurology, COALA Center for Diagnosis and Treatment of Leukodystrophies, V. Buzzi Children's Hospital, Milan, Italy
- Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - Davide Tonduti
- Unit of Pediatric Neurology, COALA Center for Diagnosis and Treatment of Leukodystrophies, V. Buzzi Children's Hospital, Milan, Italy
- Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - Stephana Carelli
- Pediatric Clinical Research Center "Romeo ed Enrica Invernizzi," Department of Biomedical and Clinical Sciences, University of Milano, Milan, Italy
- Center of Functional Genomics and Rare Diseases, Department of Pediatrics, Buzzi Children's Hospital, Milan, Italy
| | - Cristina Cereda
- Center of Functional Genomics and Rare Diseases, Department of Pediatrics, Buzzi Children's Hospital, Milan, Italy
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5
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Siori D, Vlachakis D, Makrythanasis P, Traeger-Synodinos J, Veltra D, Kampouraki A, Chrousos GP. A TMEM63A Nonsense Heterozygous Variant Linked to Infantile Transient Hypomyelinating Leukodystrophy Type 19? Genes (Basel) 2024; 15:525. [PMID: 38790154 PMCID: PMC11120763 DOI: 10.3390/genes15050525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 04/07/2024] [Accepted: 04/17/2024] [Indexed: 05/26/2024] Open
Abstract
Infantile onset transient hypomyelination (IOTH) is a rare form of leukodystrophy that is associated with transient motor impairment and delayed central nervous system myelination. Here, we report a case of a new mutation in the transmembrane protein 63A (TMEM63A) gene identified using Whole-Exome Sequencing (WES) in an 8.5-year-old boy with clinical symptoms similar to IOTH. The patient exhibited a mild developmental delay, including hypotonia and delayed motor milestones, as well as some notable phenotypic characteristics, such as macrocephaly and macrosomia. Despite the absence of early neuroimaging, genetic testing revealed a paternally inherited variant in TMEM63A (NM_14698.3:c.220A>T;p:(Arg74*)), potentially linked to infantile transient hypomyelinating leukodystrophy type 19. Our findings in this study and the patient's favorable clinical course underscore the potential for successful myelination even with delayed initiation and may contribute to a better understanding of the genotype-phenotype correlation in IOTH, emphasizing the importance of genetic analysis in unresolved developmental delay cases and providing critical insights for accurate diagnosis, prognosis and potential therapeutic strategies in rare leukodystrophies.
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Affiliation(s)
- Dimitra Siori
- University Research Institute of Maternal and Child Health and Precision Medicine, School of Medicine, National Kapodistrian University of Athens, 115 27 Athens, Greece; (D.S.); (D.V.)
- Clinical and Translational Research Endocrine Unit, School of Medicine, National Kapodistrian University of Athens, 115 28 Athens, Greece
| | - Dimitrios Vlachakis
- University Research Institute of Maternal and Child Health and Precision Medicine, School of Medicine, National Kapodistrian University of Athens, 115 27 Athens, Greece; (D.S.); (D.V.)
- Laboratory of Genetics, Department of Biotechnology, School of Applied Biology and Biotechnology, Agricultural University of Athens, 75 Iera Odos, 11855 Athens, Greece
- School of Informatics, Faculty of Natural & Mathematical Sciences, King’s College London, Bush House, Strand, London WC2R 2LS, UK
| | - Periklis Makrythanasis
- Laboratory of Medical Genetics, School of Medicine, National Kapodistrian University of Athens, 115 27 Athens, Greece
- Department of Genetic Medicine and Development, Medical School, University of Geneva, 1211 Geneva, Switzerland
- Biomedical Research Foundation of the Academy of Athens, 115 27 Athens, Greece
| | - Joanne Traeger-Synodinos
- Laboratory of Medical Genetics, School of Medicine, National Kapodistrian University of Athens, 115 27 Athens, Greece
| | - Danai Veltra
- Laboratory of Medical Genetics, School of Medicine, National Kapodistrian University of Athens, 115 27 Athens, Greece
| | - Afrodite Kampouraki
- Laboratory of Medical Genetics, School of Medicine, National Kapodistrian University of Athens, 115 27 Athens, Greece
| | - George P. Chrousos
- University Research Institute of Maternal and Child Health and Precision Medicine, School of Medicine, National Kapodistrian University of Athens, 115 27 Athens, Greece; (D.S.); (D.V.)
- Clinical and Translational Research Endocrine Unit, School of Medicine, National Kapodistrian University of Athens, 115 28 Athens, Greece
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Biglari S, Vahidnezhad H, Tabatabaiefar MA, Khorram Khorshid HR, Esmaeilzadeh E. RARS1-related hypomyelinating leukodystrophy-9 (HLD-9) in two distinct Iranian families: Case report and literature review. Mol Genet Genomic Med 2024; 12:e2435. [PMID: 38618971 PMCID: PMC11017294 DOI: 10.1002/mgg3.2435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 03/04/2024] [Accepted: 03/19/2024] [Indexed: 04/16/2024] Open
Abstract
BACKGROUND Hypomyelinating leukodystrophy-9 (HLD-9) is caused by biallelic pathogenic variants in RARS1, which codes for the cytoplasmic tRNA synthetase for arginine (ArgRS). This study aims to evaluate the clinical, neuroradiological, and genetic characteristics of patients with RARS1-related disease and determine probable genotype-phenotype relationships. METHODS We identified three patients with RARS1 homozygous pathogenic variants. Furthermore, we performed a comprehensive review of the literature. RESULTS Homozygous variants of RARS1 (c.2T>C (p.Met1Thr)) were identified in three patients with HLD-9. Clinical symptoms were severe in all patients. Following the literature review, thirty HLD-9 cases from eight studies were found. The 33 patients' main symptoms were hypomyelination, language delay, and intellectual disability or developmental delay. The mean age of onset for HLD9 in the group of 33 patients with a known age of onset was 5.8 months (SD = 8.1). The interquartile range of age of onset was 0-10 months. Of the 25 variants identified, c.5A>G (p.Asp2Gly) was identified in 11 patients. CONCLUSION Pathogenic variants in RARS1 decrease ArgRS activity and cause a wide range of symptoms, from severe, early onset epileptic encephalopathy with brain atrophy to a mild condition with relatively maintained myelination. These symptoms include the classic hypomyelination presentation with nystagmus and spasticity. Furthermore, the pathogenicity of the variation c.2T>C (p.Met1Thr) has been shown.
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Affiliation(s)
- Sajjad Biglari
- Department of Genetics and Molecular Biology, School of MedicineIsfahan University of Medical SciencesIsfahanIran
| | - Hassan Vahidnezhad
- Division of Human GeneticsChildren's Hospital of PhiladelphiaPhiladelphiaPennsylvaniaUSA
- Center for Applied GenomicsChildren's Hospital of PhiladelphiaPhiladelphiaPennsylvaniaUSA
- Department of PediatricsUniversity of Pennsylvania, Perelman School of MedicinePhiladelphiaPennsylvaniaUSA
| | - Mohammad Amin Tabatabaiefar
- Department of Genetics and Molecular Biology, School of MedicineIsfahan University of Medical SciencesIsfahanIran
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Li Y, Wan LP, Song NN, Ding YQ, Zhao S, Niu J, Mao B, Sheng N, Ma P. RNF220-mediated K63-linked polyubiquitination stabilizes Olig proteins during oligodendroglial development and myelination. SCIENCE ADVANCES 2024; 10:eadk3931. [PMID: 38324685 PMCID: PMC10849602 DOI: 10.1126/sciadv.adk3931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 01/05/2024] [Indexed: 02/09/2024]
Abstract
Maldevelopment of oligodendroglia underlies neural developmental disorders such as leukodystrophy. Precise regulation of the activity of specific transcription factors (TFs) by various posttranslational modifications (PTMs) is required to ensure proper oligodendroglial development and myelination. However, the role of ubiquitination of these TFs during oligodendroglial development is yet unexplored. Here, we find that RNF220, a known leukodystrophy-related E3 ubiquitin ligase, is required for oligodendroglial development. RNF220 depletion in oligodendrocyte lineage cells impedes oligodendrocyte progenitor cell proliferation, differentiation, and (re)myelination, which consequently leads to learning and memory defects. Mechanistically, RNF220 targets Olig1/2 for K63-linked polyubiquitination and stabilization during oligodendroglial development. Furthermore, in a knock-in mouse model of leukodystrophy-related RNF220R365Q mutation, the ubiquitination and stabilization of Olig proteins are deregulated in oligodendroglial cells. This results in pathomimetic oligodendroglial developmental defects, impaired myelination, and abnormal behaviors. Together, our evidence provides an alternative insight into PTMs of oligodendroglial TFs and how this essential process may be implicated in the etiology of leukodystrophy.
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Affiliation(s)
- Yuwei Li
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming 650223, China
| | - Li Pear Wan
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming 650223, China
- Key Laboratory of Animal Models and Human Disease Mechanisms of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
| | - Ning-Ning Song
- Department of Laboratory Animal Science, Fudan University, Shanghai 200032, China
| | - Yu-Qiang Ding
- Department of Laboratory Animal Science, Fudan University, Shanghai 200032, China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200032, China
| | - Shuhua Zhao
- First Affiliated Hospital of Kunming Medical University, Kunming 650032, China
| | - Jianqin Niu
- Department of Histology and Embryology, Third Military Medical University, Chongqing 400038, China
| | - Bingyu Mao
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China
| | - Nengyin Sheng
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
- Key Laboratory of Animal Models and Human Disease Mechanisms of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China
| | - Pengcheng Ma
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
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8
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Hülsmeier AJ, Toelle SP, Bellstedt P, Wentzel C, Bahr A, Kolokotronis K, Hornemann T. The atypical sphingolipid SPB 18:1(14Z);O2 is a biomarker for DEGS1 related hypomyelinating leukodystrophy. J Lipid Res 2023; 64:100464. [PMID: 37890668 PMCID: PMC10696257 DOI: 10.1016/j.jlr.2023.100464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 10/20/2023] [Accepted: 10/21/2023] [Indexed: 10/29/2023] Open
Abstract
Sphingolipids (SL) represent a structurally diverse class of lipids that are central to cellular physiology and neuronal development and function. Defects in the sphingolipid metabolism are typically associated with nervous system disorders. The C4-dihydroceramide desaturase (DEGS1) catalyzes the conversion of dihydroceramide to ceramide, the final step in the SL de-novo synthesis. Loss of function mutations in DEGS1 cause a hypomyelinating leukodystrophy, which is associated with increased plasma dihydrosphingolipids (dhSL) and with the formation of an atypical SPB 18:1(14Z);O2 metabolite. Here, we characterize two novel DEGS1 variants of unknown significance (VUS), provide a structural model with a predicted substrate binding site, and propose a regulatory link between DEGS1 and fatty acid desaturase 3 (FADS3). Both VUS involve single amino acid substitutions near the C-terminus within conserved regions of the enzyme. Patient 1 (p.R311K variant) shows severe progressive tetraspasticity, intellectual disability, and epilepsy in combination with brain magnetic resonance imaging (MRI) findings, typical for DEGS1-related leukodystrophy. Patient 2 (p.G270E variant) presents with delayed psychomotor development, oculomotor apraxia, and a normal brain MRI. Plasma from the p.R311K carrier showed a significantly elevated dhSL species and the presence of SPB 18:1(14Z);O2, while the plasma SL profile for the p.G270E variant was not altered. This suggests the p.R331K variant is pathogenic, while the p.G270E appears benign. As an increase in dihydroSL species is also seen in other pathological disorders of the SL metabolism, the SPB 18:1(14Z);O2 seems to be a more specific biomarker to discriminate between pathogenic and benign DEGS1 variants.
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Affiliation(s)
- Andreas J Hülsmeier
- Institute of Clinical Chemistry, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
| | - Sandra P Toelle
- Department of Pediatric Neurology, University Children's Hospital, Zurich, University of Zurich, Zurich, Switzerland
| | - Peter Bellstedt
- Institute of Clinical Chemistry, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Christian Wentzel
- Department of Women's and Children's Health, Pediatric Oncological and Neurological Research, Uppsala University, Uppsala, Sweden
| | - Angela Bahr
- Institute of Medical Genetics, University of Zurich, Schlieren, Zurich, Switzerland
| | | | - Thorsten Hornemann
- Institute of Clinical Chemistry, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
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9
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Chen X, Wang N, Liu JW, Zeng B, Chen GL. TMEM63 mechanosensitive ion channels: Activation mechanisms, biological functions and human genetic disorders. Biochem Biophys Res Commun 2023; 683:149111. [PMID: 37857161 DOI: 10.1016/j.bbrc.2023.10.043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/27/2023] [Accepted: 10/11/2023] [Indexed: 10/21/2023]
Abstract
The transmembrane 63 (TMEM63) family of proteins are originally identified as homologs of the osmosensitive calcium-permeable (OSCA) channels in plants. Mechanosensitivity of OSCA and TMEM63 proteins are recently demonstrated in addition to their proposed activation mechanism by hyper/hypo-osmolarity. TMEM63 proteins exist in all animals, with a single member in Drosophila (TMEM63) and three members in mammals (TMEM63 A/B/C). In humans, monoallelic variants of TMEM63A have been reported to cause transient hypomyelination during infancy, or severe hypomyelination and global developmental delay. Heterozygous variants of TMEM63B are found in patients with intellectual disability and abnormal motor function and brain morphology. Biallelic variants of TMEM63C are associated with hereditary spastic paraplegias accompanied by mild or no intellectual disability. Physiological functions of TMEM63 proteins clearly recognized so far include detecting food grittiness and environmental humidity in Drosophila, and supporting hearing in mice by regulating survival of cochlear hair cells. In this review, we summarize current knowledge about the activation mechanisms and biological functions of TMEM63 channels, and provide a concise reference for researchers interested in investigating more physiological and pathogenic roles of this family of proteins with ubiquitous expression in the body.
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Affiliation(s)
- Xin Chen
- Key Laboratory of Medical Electrophysiology, Ministry of Education & Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Na Wang
- Key Laboratory of Medical Electrophysiology, Ministry of Education & Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Jia-Wei Liu
- Key Laboratory of Medical Electrophysiology, Ministry of Education & Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Bo Zeng
- Key Laboratory of Medical Electrophysiology, Ministry of Education & Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Gui-Lan Chen
- Key Laboratory of Medical Electrophysiology, Ministry of Education & Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China.
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10
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Haneda A, Hoots JK, Hagy HA, Lacy M. Case report: neuropsychological assessment in a patient with 4H leukodystrophy. Clin Neuropsychol 2023:1-18. [PMID: 37974060 DOI: 10.1080/13854046.2023.2279697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 10/31/2023] [Indexed: 11/19/2023]
Abstract
Objective: POLR3-HLD or 4H leukodystrophy is an autosomal recessive disorder characterized by hypomyelination, hypodontia, and hypogonadotropic hypogonadism, and caused by variants in POLR3A, POLR3B, POLR1C, or POLR3K genes. Neurological and non-neurological clinical features and disease severity vary. While previous studies reference variable cognition, this is the first report of 4H detailing a comprehensive neuropsychological assessment. Method: The current study presents a 20-year-old, English-speaking, right-handed, non-Hispanic White female with 12 years of education with genetically confirmed 4H POLR3B-related leukodystrophy without hormonal replacement treatment. Results: At age 4, developmental delays, ataxia, hearing loss, and abnormal dentition were present. Imaging, endocrinology, and neurologic examinations revealed hypomyelination, reduced cerebellar volume, delayed bone age density, osteopenia, and evidence of adrenarche without signs of true puberty. Neuropsychological assessment at age 20 revealed global cognitive impairment with intellectual, attention, verbal memory retrieval, construction, executive (e.g. processing speed, sustained attention) and math computation deficits, along with behavioral dysregulation. Conclusion: We present the first detailed neuropsychological assessment of a patient with 4H leukodystrophy. The neuropsychological assessment revealed cognitive and behavioral dysexecutive deficits aligning with hypomyelination observed on imaging. Further longitudinal studies are needed to shed light on the neurobehavioral presentation associated with this disorder to assist care providers, patients, and their families.
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Affiliation(s)
- Aya Haneda
- Department of Psychology, Roosevelt University, Chicago, IL, USA
- University of Chicago Medical Center, Department of Psychiatry and Behavioral Neuroscience, Chicago, IL, USA
| | - Jennifer K Hoots
- University of Chicago Medical Center, Department of Psychiatry and Behavioral Neuroscience, Chicago, IL, USA
- Department of Psychology, University of Illinois Chicago, Chicago, IL, USA
| | - Hannah A Hagy
- University of Chicago Medical Center, Department of Psychiatry and Behavioral Neuroscience, Chicago, IL, USA
- Loyola University, Chicago, IL, USA
| | - Maureen Lacy
- University of Chicago Medical Center, Department of Psychiatry and Behavioral Neuroscience, Chicago, IL, USA
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11
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Jagielska A, Radzwill K, Espinosa-Hoyos D, Yang M, Kowsari K, Farley JE, Giera S, Byrne A, Sheng G, Fang NX, Dodge JC, Pedraza CE, Van Vliet KJ. Artificial axons as a biomimetic 3D myelination platform for the discovery and validation of promyelinating compounds. Sci Rep 2023; 13:19529. [PMID: 37945646 PMCID: PMC10636046 DOI: 10.1038/s41598-023-44675-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 10/11/2023] [Indexed: 11/12/2023] Open
Abstract
Multiple sclerosis (MS), a chronic neurodegenerative disease driven by damage to the protective myelin sheath, is currently incurable. Today, all clinically available treatments modulate the immune-mediated symptoms of the disease but they fail to stop neurodegeneration in many patients. Remyelination, the regenerative process of myelin repair by oligodendrocytes, which is considered a necessary step to protect demyelinated axons and stop neuronal death, is impaired in MS patients. One of the major obstacles to finding effective remyelinating drugs is the lack of biomimetic drug screening platforms that enable quantification of compounds' potential to stimulate 3D myelination in the physiologically relevant axon-like environment. To address this need, we built a unique myelination drug discovery platform, by expanding our previously developed technology, artificial axons (AAs), which enables 3D-printing of synthetic axon mimics with the geometry and mechanical properties closely resembling those of biological axons. This platform allows for high-throughput phenotypic myelination assay based on quantification of 3D wrapping of myelin membrane around axons in response to compounds. Here, we demonstrate quantification of 3D myelin wrapping by rat oligodendrocytes around the axon mimics in response to a small library of known pro-myelinating compounds. This assay shows pro-myelinating activity for all tested compounds consistent with the published in vitro and in vivo data, demonstrating predictive power of AA platform. We find that stimulation of myelin wrapping by these compounds is dose-dependent, providing a facile means to quantify the compounds' potency and efficacy in promoting myelin wrapping. Further, the ranking of relative efficacy among these compounds differs in this 3D axon-like environment as compared to a traditional oligodendrocyte 2D differentiation assay quantifying area of deposited myelin membrane. Together, we demonstrate that the artificial axons platform and associated phenotypic myelin wrapping assay afford direct evaluation of myelin wrapping by oligodendrocytes in response to soluble compounds in an axon-like environment, providing a predictive tool for the discovery of remyelinating therapies.
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Affiliation(s)
- Anna Jagielska
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Artificial Axon Labs, Boston, MA, USA.
| | | | - Daniela Espinosa-Hoyos
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Sanofi, Cambridge, MA, USA
| | - Mingyu Yang
- Harvard-MIT Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Kavin Kowsari
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Merck, Rahway, NJ, USA
| | - Jonathan E Farley
- Sanofi, Cambridge, MA, USA
- Alnylam Pharmaceuticals, Cambridge, MA, USA
| | | | | | | | - Nicholas X Fang
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- The University of Hong Kong, Hong Kong, China
| | | | | | - Krystyn J Van Vliet
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Cornell University, Ithaca, NY, USA.
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12
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Sano K, Miya F, Kato M, Omata T, Takanashi JI. Neurochemistry evaluated by magnetic resonance spectroscopy in a patient with FBXO28-related developmental and epileptic encephalopathy. Brain Dev 2023; 45:583-587. [PMID: 37543484 DOI: 10.1016/j.braindev.2023.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 06/27/2023] [Accepted: 07/11/2023] [Indexed: 08/07/2023]
Abstract
BACKGROUND Mutations in the FBXO28 gene, which encodes FBXO28, one of the F-box protein family, may cause developmental and epileptic encephalopathy (DEE). FBXO28-related DEE is radiologically characterized by cerebral atrophy, delayed/abnormal myelination, and brain malformation; however, no neurochemical analyses have been reported. CASE REPORT A female Japanese infant presented with severe psychomotor delay, epileptic spasms, and visual impairment. Whole-exome sequencing revealed a de novo variant of the FBXO28 gene, leading to the diagnosis of FBXO28-related DEE. Magnetic resonance (MR) spectroscopy at 6, 12, and 32 months revealed decreased N-acetylaspartate and choline-containing compounds and increased levels of myoinositol. CONCLUSION MR spectroscopy revealed neurochemical derangement in FBXO28-related DEE, that is, disturbed myelination secondary to neuronal damage with astrogliosis.
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Affiliation(s)
- Kentaro Sano
- Department of Pediatrics, Tokyo Women's Medical University Yachiyo Medical Center, 477-96, Owada shinden, Yachiyo, Chiba 276-0046, Japan
| | - Fuyuki Miya
- Center for Medical Genetics, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Mitsuhiro Kato
- Department of Pediatrics, Showa University School of Medicine, 1-5-8, Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
| | - Taku Omata
- Department of Pediatrics, Tokyo Women's Medical University Yachiyo Medical Center, 477-96, Owada shinden, Yachiyo, Chiba 276-0046, Japan
| | - Jun-Ichi Takanashi
- Department of Pediatrics, Tokyo Women's Medical University Yachiyo Medical Center, 477-96, Owada shinden, Yachiyo, Chiba 276-0046, Japan.
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13
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Mirchi A, Guay SP, Tran LT, Wolf NI, Vanderver A, Brais B, Sylvain M, Pohl D, Rossignol E, Saito M, Moutton S, González-Gutiérrez-Solana L, Thiffault I, Kruer MC, Moron DG, Kauffman M, Goizet C, Sztriha L, Glamuzina E, Melançon SB, Naidu S, Retrouvey JM, Lacombe S, Bernardino-Cuesta B, De Bie I, Bernard G. Craniofacial features of POLR3-related leukodystrophy caused by biallelic variants in POLR3A, POLR3B and POLR1C. J Med Genet 2023; 60:1026-1034. [PMID: 37197783 PMCID: PMC10579516 DOI: 10.1136/jmg-2023-109223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 04/16/2023] [Indexed: 05/19/2023]
Abstract
BACKGROUND RNA polymerase III-related or 4H leukodystrophy (POLR3-HLD) is an autosomal recessive hypomyelinating leukodystrophy characterized by neurological dysfunction, hypodontia and hypogonadotropic hypogonadism. The disease is caused by biallelic pathogenic variants in POLR3A, POLR3B, POLR1C or POLR3K. Craniofacial abnormalities reminiscent of Treacher Collins syndrome have been originally described in patients with POLR3-HLD caused by biallelic pathogenic variants in POLR1C. To date, no published studies have appraised in detail the craniofacial features of patients with POLR3-HLD. In this work, the specific craniofacial characteristics of patients with POLR3-HLD associated with biallelic pathogenic variants in POLR3A, POLR3B and POLR1C are described. METHODS The craniofacial features of 31 patients with POLR3-HLD were evaluated, and potential genotype-phenotype associations were evaluated. RESULTS Various craniofacial abnormalities were recognized in this patient cohort, with each individual presenting at least one craniofacial abnormality. The most frequently identified features included a flat midface (61.3%), a smooth philtrum (58.0%) and a pointed chin (51.6%). In patients with POLR3B biallelic variants, a thin upper lip was frequent. Craniofacial anomalies involving the forehead were most commonly associated with biallelic variants in POLR3A and POLR3B while a higher proportion of patients with POLR1C biallelic variants demonstrated bitemporal narrowing. CONCLUSION Through this study, we demonstrated that craniofacial abnormalities are common in patients with POLR3-HLD. This report describes in detail the dysmorphic features of POLR3-HLD associated with biallelic variants in POLR3A, POLR3B and POLR1C.
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Affiliation(s)
- Amytice Mirchi
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
- Department of Pediatrics, McGill University, Montreal, Quebec, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Simon-Pierre Guay
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, Quebec, Canada
| | - Luan T Tran
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Nicole I Wolf
- Department of Child Neurology, Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers, and Amsterdam Neuroscience, Cellular & Molecular Mechanisms, Vrije Universiteit, Amsterdam, Netherlands
| | - Adeline Vanderver
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Bernard Brais
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
- Montreal Neurological Institute, Montreal, Quebec, Canada
| | - Michel Sylvain
- Centre Mère Enfant, CHU de Québec, Québec City, Quebec, Canada
| | - Daniela Pohl
- Division of Neurology, Children's Hospital of Eastern Ontario, University of Ottawa, Ottawa, Ontario, Canada
| | - Elsa Rossignol
- Departments of Neurosciences and Pediatrics, CHU-Sainte-Justine, Université de Montréal, Montreal, Quebec, Canada
| | - Michael Saito
- Department of Pediatrics, University of California Riverside School of Medicine, Riverside Medical Clinic, Riverside, California, USA
| | - Sebastien Moutton
- Centre Pluridisciplinaire de Diagnostic PréNatal, MSPBordeaux Bagatelle, Talence, France
| | - Luis González-Gutiérrez-Solana
- Sección de Neuropediatría, Hospital Infantil Universitario Niño Jesús, Madrid, España; Grupo Clínico Vinculado al Centro de Investigación Biomédica en Red para Enfermedades Raras (CIBERER) GCV14/ER/6, Hospital Infantil Universitario Nino Jesus, Madrid, Spain
| | - Isabelle Thiffault
- Genomic Medicine Center, Children's Mercy Hospital, Kansas City, Missouri, USA
- University of Missouri Kansas City School of Medicine, Kansas City, Missouri, USA
| | - Michael C Kruer
- Departments of Child Health, Neurology, and Cellular & Molecular Medicine and Program in Genetics, University of Arizona College of Medicine, Phoenix, Arizona, USA
- Programs in Neuroscience and Molecular & Cellular Biology, School of Life Sciences, Arizona State University, Tempe, Arizona, USA
- Pediatric Movement Disorders Program, Barrow Neurological Institute, Phoenix Children's Hospital, Phoenix, Arizona, USA
| | - Dolores Gonzales Moron
- Neurogenetics Unit, Department of Neurology, Hospital JM Ramos Mejia, ADC, Buenos Aires, Argentina
| | - Marcelo Kauffman
- Neurogenetics Unit, Department of Neurology, Hospital JM Ramos Mejia and CONICET-Universidad Austral, Buenos Aires, Argentina
| | - Cyril Goizet
- Centre de Référence Neurogénétique, Service de Génétique Médicale, Bordeaux University Hospital, CHU Bordeaux, Bordeaux, France
- NRGEN team, INCIA, CNRS UMR 5287, University of Bordeaux, Bordeaux, France
| | - László Sztriha
- Department of Paediatrics, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Emma Glamuzina
- Adult and Paediatric National Metabolic Service, Starship Children's Hospital, Auckland, Te Whatu Ora, New Zealand
| | - Serge B Melançon
- Department of Medical Genetics, McGill University Health Centre, Montreal Children's Hospital, Montreal, Quebec, Canada
| | - Sakkubai Naidu
- Department of Neurogenetics, Kennedy Krieger Institute, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
| | - Jean-Marc Retrouvey
- Department of Orthodontics, University of Missouri, Kansas City, Missouri, USA
| | - Suzanne Lacombe
- Department of Orthodontics, University of Missouri, Kansas City, Missouri, USA
| | | | - Isabelle De Bie
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, Quebec, Canada
- Department of Laboratory Medicine, McGill University Health Centre, Montreal, Quebec, Canada
| | - Geneviève Bernard
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
- Department of Pediatrics, McGill University, Montreal, Quebec, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, Quebec, Canada
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14
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Torii T, Yamauchi J. Molecular Pathogenic Mechanisms of Hypomyelinating Leukodystrophies (HLDs). Neurol Int 2023; 15:1155-1173. [PMID: 37755363 PMCID: PMC10538087 DOI: 10.3390/neurolint15030072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 08/29/2023] [Accepted: 09/06/2023] [Indexed: 09/28/2023] Open
Abstract
Hypomyelinating leukodystrophies (HLDs) represent a group of congenital rare diseases for which the responsible genes have been identified in recent studies. In this review, we briefly describe the genetic/molecular mechanisms underlying the pathogenesis of HLD and the normal cellular functions of the related genes and proteins. An increasing number of studies have reported genetic mutations that cause protein misfolding, protein dysfunction, and/or mislocalization associated with HLD. Insight into the mechanisms of these pathways can provide new findings for the clinical treatments of HLD.
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Affiliation(s)
- Tomohiro Torii
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji 192-0392, Japan
- Laboratory of Ion Channel Pathophysiology, Graduate School of Brain Science, Doshisha University, Kyotanabe-shi 610-0394, Japan
- Center for Research in Neurodegenerative Disease, Doshisha University, Kyotanabe-shi 610-0394, Japan
| | - Junji Yamauchi
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji 192-0392, Japan
- Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya-ku 157-8535, Japan
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15
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Wan L, Yu D, Li Z, Liu X, Liang Y, Yan H, Zhu G, Zhang B, Yang G. RARS1-related developmental and epileptic encephalopathy. Epilepsia Open 2023; 8:867-876. [PMID: 37186453 PMCID: PMC10472388 DOI: 10.1002/epi4.12751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 04/24/2023] [Indexed: 05/17/2023] Open
Abstract
OBJECTIVE Biallelic variants of RARS1, a gene that encodes the cytoplasmic tRNA synthetase for arginine (ArgRS), are associated with central nervous system (CNS) manifestations, such as hypomyelinating leukodystrophy-9 and developmental and epileptic encephalopathy (DEE). This study aimed to better understand the RARS1 biallelic mutations and the associated phenotypes, particularly in patients with DEE. METHODS We identified two patients with RARS1 biallelic mutations and functionally validated these mutations in vitro. Furthermore, we performed a review of the literature. RESULTS Two patients with hypomyelinating leukodystrophy were found to have RARS1 biallelic variants (Patient 1: c.1535G>A (p.Arg512Gln) and c.1382G>A (p.Arg461His); Patient 2: homozygous variants c.5A>T (p.Asp2Val)). Patient 2 had a severe clinical manifestation of DEE. A review of the literature identified 27 patients from five studies. Among the 29 patients, intellectual disability, developmental delay, and hypomyelination were the common symptoms, while 13 of them exhibited DEE and malformations of cortical development. Of the 25 variants identified, c.5A>G (p.Asp2Gly) was identified in 10 patients. ArgRS protein expression and stability were substantially reduced in the two newly identified patients. SIGNIFICANCE Patients with RARS1 biallelic mutations frequently exhibit DEE, a severe phenotype, along with hypomyelinating leukodystrophy. Besides its effects on the white matter, this mutation also influences cortical development. Moreover, the variants c.5A>T (p.Asp2Val), c.1382G>A (p.Arg461His), and c.1535G>A (p.Arg512Gln) are pathogenic and affect the expression of ArgRS by reducing the protein stability.
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Affiliation(s)
- Lin Wan
- Department of Pediatrics, The Seventh Medical Center of PLA General HospitalBeijingChina
- Department of Pediatrics, The First Medical CentreChinese PLA General HospitalBeijingChina
- Department of PediatricsMedical School of Chinese People’s Liberation ArmyBeijingChina
| | - Dan Yu
- Department of PediatricsWest China Second Hospital of Sichuan UniversityChengduChina
| | - Zhichao Li
- Department of Pediatrics, The Seventh Medical Center of PLA General HospitalBeijingChina
- Department of Pediatrics, The First Medical CentreChinese PLA General HospitalBeijingChina
- Department of PediatricsMedical School of Chinese People’s Liberation ArmyBeijingChina
| | - Xinting Liu
- Department of Pediatrics, The Seventh Medical Center of PLA General HospitalBeijingChina
- Department of Pediatrics, The First Medical CentreChinese PLA General HospitalBeijingChina
- Department of PediatricsMedical School of Chinese People’s Liberation ArmyBeijingChina
| | - Yan Liang
- Department of Pediatrics, The Seventh Medical Center of PLA General HospitalBeijingChina
- Department of Pediatrics, The First Medical CentreChinese PLA General HospitalBeijingChina
- Department of PediatricsMedical School of Chinese People’s Liberation ArmyBeijingChina
| | - Huimin Yan
- Department of Pediatrics, The Seventh Medical Center of PLA General HospitalBeijingChina
- Department of Pediatrics, The First Medical CentreChinese PLA General HospitalBeijingChina
- Department of PediatricsMedical School of Chinese People’s Liberation ArmyBeijingChina
| | - Gang Zhu
- Department of Pediatrics, The Seventh Medical Center of PLA General HospitalBeijingChina
- Department of Pediatrics, The First Medical CentreChinese PLA General HospitalBeijingChina
- Department of PediatricsMedical School of Chinese People’s Liberation ArmyBeijingChina
| | - Bo Zhang
- Department of Neurology, ICCTR Biostatistics and Research Design Center, Boston Children's HospitalHarvard Medical SchoolMassachusettsBostonUSA
| | - Guang Yang
- Department of Pediatrics, The Seventh Medical Center of PLA General HospitalBeijingChina
- Department of Pediatrics, The First Medical CentreChinese PLA General HospitalBeijingChina
- Department of PediatricsMedical School of Chinese People’s Liberation ArmyBeijingChina
- Department of Pediatrics, The Second School of Clinical MedicineSouthern Medical UniversityGuangzhouChina
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16
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Tijaro-Bulla S, Nyandwi SP, Cui H. Physiological and engineered tRNA aminoacylation. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1789. [PMID: 37042417 DOI: 10.1002/wrna.1789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 03/11/2023] [Accepted: 03/21/2023] [Indexed: 04/13/2023]
Abstract
Aminoacyl-tRNA synthetases form the protein family that controls the interpretation of the genetic code, with tRNA aminoacylation being the key chemical step during which an amino acid is assigned to a corresponding sequence of nucleic acids. In consequence, aminoacyl-tRNA synthetases have been studied in their physiological context, in disease states, and as tools for synthetic biology to enable the expansion of the genetic code. Here, we review the fundamentals of aminoacyl-tRNA synthetase biology and classification, with a focus on mammalian cytoplasmic enzymes. We compile evidence that the localization of aminoacyl-tRNA synthetases can be critical in health and disease. In addition, we discuss evidence from synthetic biology which made use of the importance of subcellular localization for efficient manipulation of the protein synthesis machinery. This article is categorized under: RNA Processing Translation > Translation Regulation RNA Processing > tRNA Processing RNA Export and Localization > RNA Localization.
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Affiliation(s)
| | | | - Haissi Cui
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
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17
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Sangster M, Shahriar S, Niziolek Z, Carisi MC, Lewandowski M, Budnik B, Grishchuk Y. Brain cell type specific proteomics approach to discover pathological mechanisms in the childhood CNS disorder mucolipidosis type IV. Front Mol Neurosci 2023; 16:1215425. [PMID: 37609073 PMCID: PMC10440433 DOI: 10.3389/fnmol.2023.1215425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 07/17/2023] [Indexed: 08/24/2023] Open
Abstract
Mucolipidosis IV (MLIV) is an ultra-rare, recessively inherited lysosomal disorder resulting from inactivating mutations in MCOLN1, the gene encoding the lysosomal cation channel TRPML1. The disease primarily affects the central nervous system (CNS) and manifests in the first year with cognitive and motor developmental delay, followed by a gradual decline in neurological function across the second decade of life, blindness, and premature death in third or fourth decades. Brain pathology manifestations in MLIV are consistent with hypomyelinating leukodystrophy with brain iron accumulation. Presently, there are no approved or investigational therapies for MLIV, and pathogenic mechanisms remain largely unknown. The MLIV mouse model, Mcoln1-/- mice, recapitulates all major manifestations of the human disease. Here, to better understand the pathological mechanisms in the MLIV brain, we performed cell type specific LC-MS/MS proteomics analysis in the MLIV mouse model and reconstituted molecular signatures of the disease in either freshly isolated populations of neurons, astrocytes, oligodendrocytes, and neural stem cells, or whole tissue cortical homogenates from young adult symptomatic Mcoln1-/- mice. Our analysis confirmed on the molecular level major histopathological hallmarks of MLIV universally present in Mcoln1-/- tissue and brain cells, such as hypomyelination, lysosomal dysregulation, and impaired metabolism of lipids and polysaccharides. Importantly, pathway analysis in brain cells revealed mitochondria-related alterations in all Mcoln1-/- brain cells, except oligodendrocytes, that was not possible to resolve in whole tissue. We also report unique proteome signatures and dysregulated pathways for each brain cell population used in this study. These data shed new light on cell-intrinsic mechanisms of MLIV and provide new insights for biomarker discovery and validation to advance translational studies for this disease.
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Affiliation(s)
- Madison Sangster
- Center for Genomic Medicine and Department of Neurology, Massachusetts General Hospital Research Institute and Harvard Medical School, Boston, MA, United States
| | - Sanjid Shahriar
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, United States
| | - Zachary Niziolek
- Bauer Flow Cytometry Core, Harvard University, Cambridge, MA, United States
| | - Maria Carla Carisi
- Center for Genomic Medicine and Department of Neurology, Massachusetts General Hospital Research Institute and Harvard Medical School, Boston, MA, United States
| | - Michael Lewandowski
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, United States
| | - Bogdan Budnik
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, United States
| | - Yulia Grishchuk
- Center for Genomic Medicine and Department of Neurology, Massachusetts General Hospital Research Institute and Harvard Medical School, Boston, MA, United States
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18
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Feng L, Chao J, Ye P, Luong Q, Sun G, Liu W, Cui Q, Flores S, Jackson N, Shayento ANH, Sun G, Liu Z, Hu W, Shi Y. Developing Hypoimmunogenic Human iPSC-Derived Oligodendrocyte Progenitor Cells as an Off-The-Shelf Cell Therapy for Myelin Disorders. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2206910. [PMID: 37271923 PMCID: PMC10427412 DOI: 10.1002/advs.202206910] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 04/27/2023] [Indexed: 06/06/2023]
Abstract
Demyelinating disorders are among the most common and debilitating diseases in neurology. Canavan disease (CD) is a lethal demyelinating disease caused by mutation of the aspartoacylase (ASPA) gene, which leads to the accumulation of its substrate N-acetyl-l-aspartate (NAA), and consequently demyelination and vacuolation in the brain. In this study, hypoimmunogenic human induced pluripotent stem cell (iPSC)-derived oligodendrocyte progenitor cells (OPC) are developed from a healthy donor as an "off-the-shelf" cell therapy. Hypoimmunogenic iPSCs are generated through CRISPR/Cas9 editing of the human leukocyte antigen (HLA) molecules in healthy donor-derived iPSCs and differentiated into OPCs. The OPCs are engrafted into the brains of CD (nur7) mice and exhibit widespread distribution in the brain. The engrafted OPCs mature into oligodendrocytes that express the endogenous wildtype ASPA gene. Consequently, the transplanted mice exhibit elevated human ASPA expression and enzymatic activity and reduced NAA level in the brain. The transplanted OPCs are able to rescue major pathological features of CD, including defective myelination, extensive vacuolation, and motor function deficits. Moreover, the hypoimmunogenic OPCs exhibit low immunogenicity both in vitro and in vivo. The hypoimmunogenic OPCs can be used as "off-the-shelf" universal donor cells to treat various CD patients and many other demyelinating disorders, especially autoimmune demyelinating diseases, such as multiple sclerosis.
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Affiliation(s)
- Lizhao Feng
- Department of Neurodegenerative DiseasesBeckman Research Institute of City of Hope1500 E. Duarte Rd.DuarteCA91010USA
| | - Jianfei Chao
- Department of Neurodegenerative DiseasesBeckman Research Institute of City of Hope1500 E. Duarte Rd.DuarteCA91010USA
| | - Peng Ye
- Department of Neurodegenerative DiseasesBeckman Research Institute of City of Hope1500 E. Duarte Rd.DuarteCA91010USA
| | - Qui Luong
- Department of Neurodegenerative DiseasesBeckman Research Institute of City of Hope1500 E. Duarte Rd.DuarteCA91010USA
| | - Guoqiang Sun
- Department of Neurodegenerative DiseasesBeckman Research Institute of City of Hope1500 E. Duarte Rd.DuarteCA91010USA
| | - Wei Liu
- Department of Neurodegenerative DiseasesBeckman Research Institute of City of Hope1500 E. Duarte Rd.DuarteCA91010USA
| | - Qi Cui
- Department of Neurodegenerative DiseasesBeckman Research Institute of City of Hope1500 E. Duarte Rd.DuarteCA91010USA
| | - Sergio Flores
- Department of Neurodegenerative DiseasesBeckman Research Institute of City of Hope1500 E. Duarte Rd.DuarteCA91010USA
| | - Natasha Jackson
- Department of Neurodegenerative DiseasesBeckman Research Institute of City of Hope1500 E. Duarte Rd.DuarteCA91010USA
| | - Afm Nazmul Hoque Shayento
- Department of Neurodegenerative DiseasesBeckman Research Institute of City of Hope1500 E. Duarte Rd.DuarteCA91010USA
| | - Guihua Sun
- Department of Neurodegenerative DiseasesBeckman Research Institute of City of Hope1500 E. Duarte Rd.DuarteCA91010USA
| | - Zhenqing Liu
- Department of Neurodegenerative DiseasesBeckman Research Institute of City of Hope1500 E. Duarte Rd.DuarteCA91010USA
| | - Weidong Hu
- Department of Neurodegenerative DiseasesBeckman Research Institute of City of Hope1500 E. Duarte Rd.DuarteCA91010USA
- Department of Immunology and TheranosticsBeckman Research Institute of City of Hope1500 E. Duarte Rd.DuarteCA91010USA
| | - Yanhong Shi
- Department of Neurodegenerative DiseasesBeckman Research Institute of City of Hope1500 E. Duarte Rd.DuarteCA91010USA
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19
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Xing S, Zheng X, Yan H, Mo Y, Duan R, Chen Z, Wang K, Gao K, Chen T, Zhao S, Wang J, Chen L. Superresolution live-cell imaging reveals that the localization of TMEM106B to filopodia in oligodendrocytes is compromised by the hypomyelination-related D252N mutation. SCIENCE CHINA. LIFE SCIENCES 2023; 66:1858-1868. [PMID: 37129766 DOI: 10.1007/s11427-022-2290-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 01/30/2023] [Indexed: 05/03/2023]
Abstract
Hypomyelination leukodystrophies constitute a group of heritable white matter disorders exhibiting defective myelin development. Initially identified as a lysosomal protein, the TMEM106B D252N mutant has recently been associated with hypomyelination. However, how lysosomal TMEM106B facilitates myelination and how the D252N mutation disrupts that process are poorly understood. We used superresolution Hessian structured illumination microscopy (Hessian-SIM) and spinning disc-confocal structured illumination microscopy (SD-SIM) to find that the wild-type TMEM106B protein is targeted to the plasma membrane, filopodia, and lysosomes in human oligodendrocytes. The D252N mutation reduces the size of lysosomes in oligodendrocytes and compromises lysosome changes upon starvation stress. Most importantly, we detected reductions in the length and number of filopodia in cells expressing the D252N mutant. PLP1 is the most abundant myelin protein that almost entirely colocalizes with TMEM106B, and coexpressing PLP1 with the D252N mutant readily rescues the lysosome and filopodia phenotypes of cells. Therefore, interactions between TMEM106B and PLP1 on the plasma membrane are essential for filopodia formation and myelination in oligodendrocytes, which may be sustained by the delivery of these proteins from lysosomes via exocytosis.
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Affiliation(s)
- Shijia Xing
- National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, 100871, China
| | - Xiaolu Zheng
- National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, 100871, China
| | - Huifang Yan
- Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China
| | - Yanquan Mo
- National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, 100871, China
| | - Ruoyu Duan
- Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China
- National Center for Children's Health, Department of Neurology, Beijing Children's Hospital, Capital Medical University, Beijing, 100045, China
| | - Zhixing Chen
- National Biomedical Imaging Center, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, 100871, China
| | - Kunhao Wang
- Key Laboratory of Laser Life Science, Ministry of Education, College of Biophotonics, South China Normal University, Guangzhou, 510631, China
| | - Kai Gao
- Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China
| | - Tongsheng Chen
- Key Laboratory of Laser Life Science, Ministry of Education, College of Biophotonics, South China Normal University, Guangzhou, 510631, China
| | - Shiqun Zhao
- National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, 100871, China.
| | - Jingmin Wang
- Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China.
| | - Liangyi Chen
- National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, 100871, China.
- PKU-IDG/McGovern Institute for Brain Research, Beijing, 100871, China.
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20
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Muthusamy K, Sivadasan A, Dixon L, Sudhakar S, Thomas M, Danda S, Wszolek ZK, Wierenga K, Dhamija R, Gavrilova R. Adult-onset leukodystrophies: a practical guide, recent treatment updates, and future directions. Front Neurol 2023; 14:1219324. [PMID: 37564735 PMCID: PMC10410460 DOI: 10.3389/fneur.2023.1219324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 06/19/2023] [Indexed: 08/12/2023] Open
Abstract
Adult-onset leukodystrophies though individually rare are not uncommon. This group includes several disorders with isolated adult presentations, as well as several childhood leukodystrophies with attenuated phenotypes that present at a later age. Misdiagnoses often occur due to the clinical and radiological overlap with common acquired disorders such as infectious, immune, inflammatory, vascular, metabolic, and toxic etiologies. Increased prevalence of non-specific white matter changes in adult population poses challenges during diagnostic considerations. Clinico-radiological spectrum and molecular landscape of adult-onset leukodystrophies have not been completely elucidated at this time. Diagnostic approach is less well-standardized when compared to the childhood counterpart. Absence of family history and reduced penetrance in certain disorders frequently create a dilemma. Comprehensive evaluation and molecular confirmation when available helps in prognostication, early initiation of treatment in certain disorders, enrollment in clinical trials, and provides valuable information for the family for reproductive counseling. In this review article, we aimed to formulate an approach to adult-onset leukodystrophies that will be useful in routine practice, discuss common adult-onset leukodystrophies with usual and unusual presentations, neuroimaging findings, recent advances in treatment, acquired mimics, and provide an algorithm for comprehensive clinical, radiological, and genetic evaluation that will facilitate early diagnosis and consider active treatment options when available. A high index of suspicion, awareness of the clinico-radiological presentations, and comprehensive genetic evaluation are paramount because treatment options are available for several disorders when diagnosed early in the disease course.
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Affiliation(s)
- Karthik Muthusamy
- Department of Clinical Genomics, Mayo Clinic, Jacksonville, FL, United States
| | - Ajith Sivadasan
- Department of Neurological Sciences, Christian Medical College, Tamil Nadu, Vellore, India
| | - Luke Dixon
- Department of Radiology, Imperial College, NHS Trust, London, United Kingdom
| | - Sniya Sudhakar
- Department of Radiology, Great Ormond Street Hospital, London, United Kingdom
| | - Maya Thomas
- Department of Neurological Sciences, Christian Medical College, Tamil Nadu, Vellore, India
| | - Sumita Danda
- Department of Medical Genetics, Christian Medical College, Vellore, Tamil Nadu, India
| | | | - Klaas Wierenga
- Department of Clinical Genomics, Mayo Clinic, Jacksonville, FL, United States
| | - Radhika Dhamija
- Department of Clinical Genomics and Neurology, Mayo Clinic, Phoenix, AZ, United States
| | - Ralitza Gavrilova
- Department of Clinical Genomics and Neurology, Mayo Clinic, Rochester, MN, United States
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21
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Huang H, Jing B, Zhu F, Jiang W, Tang P, Shi L, Chen H, Ren G, Xia S, Wang L, Cui Y, Yang Z, Platero AJ, Hutchins AP, Chen M, Worley PF, Xiao B. Disruption of neuronal RHEB signaling impairs oligodendrocyte differentiation and myelination through mTORC1-DLK1 axis. Cell Rep 2023; 42:112801. [PMID: 37463107 DOI: 10.1016/j.celrep.2023.112801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 05/12/2023] [Accepted: 06/26/2023] [Indexed: 07/20/2023] Open
Abstract
How neuronal signaling affects brain myelination remains poorly understood. We show dysregulated neuronal RHEB-mTORC1-DLK1 axis impairs brain myelination. Neuronal Rheb cKO impairs oligodendrocyte differentiation/myelination, with activated neuronal expression of the imprinted gene Dlk1. Neuronal Dlk1 cKO ameliorates myelination deficit in neuronal Rheb cKO mice, indicating that activated neuronal Dlk1 expression contributes to impaired myelination caused by Rheb cKO. The effect of Rheb cKO on Dlk1 expression is mediated by mTORC1; neuronal mTor cKO and Raptor cKO and pharmacological inhibition of mTORC1 recapitulate elevated neuronal Dlk1 expression. We demonstrate that both a secreted form of DLK1 and a membrane-bound DLK1 inhibit the differentiation of cultured oligodendrocyte precursor cells into oligodendrocytes expressing myelin proteins. Finally, neuronal expression of Dlk1 in transgenic mice reduces the formation of mature oligodendrocytes and myelination. This study identifies Dlk1 as an inhibitor of oligodendrocyte myelination and a mechanism linking altered neuronal signaling with oligodendrocyte dysfunction.
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Affiliation(s)
- Haijiao Huang
- Departments of Neuroscience and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen Key Laboratory for Gene Regulation and Systems Biology, Shenzhen 518055, People's Republic of China
| | - Bo Jing
- Departments of Neuroscience and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen Key Laboratory for Gene Regulation and Systems Biology, Shenzhen 518055, People's Republic of China.
| | - Feiyan Zhu
- Departments of Neuroscience and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen Key Laboratory for Gene Regulation and Systems Biology, Shenzhen 518055, People's Republic of China
| | - Wanxiang Jiang
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, People's Republic of China
| | - Ping Tang
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, People's Republic of China
| | - Liyang Shi
- Departments of Neuroscience and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen Key Laboratory for Gene Regulation and Systems Biology, Shenzhen 518055, People's Republic of China
| | - Huiting Chen
- Departments of Neuroscience and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen Key Laboratory for Gene Regulation and Systems Biology, Shenzhen 518055, People's Republic of China
| | - Guoru Ren
- Departments of Neuroscience and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen Key Laboratory for Gene Regulation and Systems Biology, Shenzhen 518055, People's Republic of China
| | - Shiyao Xia
- Departments of Neuroscience and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen Key Laboratory for Gene Regulation and Systems Biology, Shenzhen 518055, People's Republic of China
| | - Luoling Wang
- Departments of Neuroscience and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen Key Laboratory for Gene Regulation and Systems Biology, Shenzhen 518055, People's Republic of China
| | - Yiyuan Cui
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, People's Republic of China
| | - Zhiwen Yang
- Departments of Neuroscience and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen Key Laboratory for Gene Regulation and Systems Biology, Shenzhen 518055, People's Republic of China
| | - Alexander J Platero
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Andrew P Hutchins
- Departments of Neuroscience and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen Key Laboratory for Gene Regulation and Systems Biology, Shenzhen 518055, People's Republic of China
| | - Mina Chen
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, People's Republic of China
| | - Paul F Worley
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Bo Xiao
- Departments of Neuroscience and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen Key Laboratory for Gene Regulation and Systems Biology, Shenzhen 518055, People's Republic of China.
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22
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Katsarogiannis E, Landtblom AM, Kristoffersson A, Wikström J, Semnic R, Berntsson SG. Absence of Oligoclonal Bands in Multiple Sclerosis: A Call for Differential Diagnosis. J Clin Med 2023; 12:4656. [PMID: 37510771 PMCID: PMC10380970 DOI: 10.3390/jcm12144656] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 07/05/2023] [Accepted: 07/11/2023] [Indexed: 07/30/2023] Open
Abstract
BACKGROUND Immunoglobulin gamma (IgG) oligoclonal bands (OCB) in the cerebrospinal fluid (CSF) are absent in a small group of multiple sclerosis (MS) patients. According to previous research, OCB-negative MS patients differ genetically but not clinically from OCB-positive MS patients. However, whether OCB-negative MS is a unique immunological and clinical entity remains unclear. The absence of OCB poses a significant challenge in diagnosing MS. (1) Objective: The objective of this study was twofold: (1) to determine the prevalence of OCB-negative MS patients in the Uppsala region, and (2) to assess the frequency of misdiagnosis in this patient group. (2) Methods: We conducted a retrospective study using data from the Swedish MS registry (SMSreg) covering 83% of prevalent MS cases up to 20 June 2020 to identify all MS patients in the Uppsala region. Subsequently, we collected relevant information from the medical records of all OCB-negative MS cases, including age of onset, gender, presenting symptoms, MRI features, phenotype, Expanded Disability Status Scale (EDSS) scores, and disease-modifying therapies (DMTs). (3) Results: Out of 759 MS patients identified, 69 had an OCB-negative MS diagnosis. Upon re-evaluation, 46 patients had a typical history and MRI findings of MS, while 23 had unusual clinical and/or radiologic features. An alternative diagnosis was established for the latter group, confirming the incorrectness of the initial MS diagnosis. The average EDSS score was 2.0 points higher in the MS group than in the non-MS group (p = 0.001). The overall misdiagnosis rate in the cohort was 33%, with 22% of misdiagnosed patients having received DMTs. (4) Conclusions: Our results confirm that the absence of OCB in the CSF should raise suspicion of possible misdiagnosis in MS patients and prompt a diagnostic reassessment.
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Affiliation(s)
| | - Anne-Marie Landtblom
- Department of Medical Sciences, Neurology, Uppsala University, SE-751 85 Uppsala, Sweden
| | - Anna Kristoffersson
- Department of Medical Sciences, Neurology, Uppsala University, SE-751 85 Uppsala, Sweden
| | - Johan Wikström
- Department of Surgical Sciences, Neuroradiology, Uppsala University, SE-751 85 Uppsala, Sweden
| | - Robert Semnic
- Department of Surgical Sciences, Neuroradiology, Uppsala University, SE-751 85 Uppsala, Sweden
| | - Shala G Berntsson
- Department of Medical Sciences, Neurology, Uppsala University, SE-751 85 Uppsala, Sweden
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23
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Fukushima N, Shirai R, Sato T, Nakamura S, Ochiai A, Miyamoto Y, Yamauchi J. Knockdown of Rab7B, But Not of Rab7A, Which Antagonistically Regulates Oligodendroglial Cell Morphological Differentiation, Recovers Tunicamycin-Induced Defective Differentiation in FBD-102b Cells. J Mol Neurosci 2023; 73:363-374. [PMID: 37248316 DOI: 10.1007/s12031-023-02117-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 04/06/2023] [Indexed: 05/31/2023]
Abstract
In the central nervous system (CNS), insulative myelin sheaths are generated from the differentiated plasma membranes of oligodendrocytes (oligodendroglial cells) and surround neuronal axons to achieve saltatory conduction. Despite the functional involvement of myelin sheaths in the CNS, the molecular mechanism by which oligodendroglial cells themselves undergo differentiation of plasma membranes remains unclear. It also remains to be explored whether their signaling mechanisms can be applied to treating diseases of the oligodendroglial cells. Here, we describe that Rab7B of Rab7 subfamily small GTPases negatively regulates oligodendroglial cell morphological differentiation using FBD-102b cells, which are model cells undergoing differentiation of oligodendroglial precursors. Knockdown of Rab7B or Rab7A by the respective specific siRNAs in cells positively or negatively regulated morphological differentiation, respectively. Consistently, these changes were supported by changes on differentiation- and myelination-related structural protein and protein kinase markers. We also found that knockdown of Rab7B has the ability to recover inhibition of morphological differentiation following tunicamycin-induced endoplasmic reticulum (ER) stress, which mimics one of the major molecular pathological causes of hereditary hypomyelinating disorders in oligodendroglial cells, such as Pelizaeus-Merzbacher disease (PMD). These results suggest that the respective molecules among very close Rab7 homologues exhibit differential roles in morphological differentiation and that knocking down Rab7B can recover defective differentiating phenotypes under ER stress, thereby adding Rab7B to the list of molecular therapeutic cues taking advantage of signaling mechanisms for oligodendroglial diseases like PMD.
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Affiliation(s)
- Nana Fukushima
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, 192-0392, Japan
| | - Remina Shirai
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, 192-0392, Japan
| | - Takanari Sato
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, 192-0392, Japan
| | - Sayumi Nakamura
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, 192-0392, Japan
| | - Arisa Ochiai
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, 192-0392, Japan
| | - Yuki Miyamoto
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, 192-0392, Japan.
- Department of Pharmacology, National Research Institute for Child Health and Development, 2-10-1, Setagaya, Tokyo, 157-8535, Japan.
| | - Junji Yamauchi
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, 192-0392, Japan.
- Department of Pharmacology, National Research Institute for Child Health and Development, 2-10-1, Setagaya, Tokyo, 157-8535, Japan.
- Diabetic Neuropathy Project, Tokyo Metropolitan Institute of Medical Science, Setagaya, Tokyo, 156-8506, Japan.
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24
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Ma J, Chen T, Wang R. Astragaloside IV ameliorates cognitive impairment and protects oligodendrocytes from antioxidative stress via regulation of the SIRT1/Nrf2 signaling pathway. Neurochem Int 2023; 167:105535. [PMID: 37209830 DOI: 10.1016/j.neuint.2023.105535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 04/08/2023] [Accepted: 04/23/2023] [Indexed: 05/22/2023]
Abstract
Subcortical ischemic vascular dementia (SIVD), which is caused by chronic cerebral hypoperfusion, is a common subtype of vascular dementia, accompanied by white matter damage and cognitive impairment. Currently, there are no effective treatments for this condition. Oxidative stress is a key factor in the pathogenesis of white matter damage. Astragaloside IV (AS-IV), one of the main active components of astragaloside, has antioxidant properties and promotes cognitive improvement; however, its effect on SIVD and its potential mechanism remain unknown. We aimed to clarify whether AS-IV had a protective effect against SIVD injury caused by right unilateral common carotid artery occlusion and the underlying mechanism. The results showed that AS-IV treatment improved cognitive function and white matter damage, inhibited oxidative stress and glial cells activation, and promoted the survival of mature oligodendrocytes after chronic cerebral hypoperfusion. Moreover, the protein expression levels of NQO1, HO-1, SIRT1 and Nrf2 were increased by AS-IV treatment. However, pre-treatment with EX-527, a SIRT1-specific inhibitor, eliminated the beneficial effects of AS-IV. These results demonstrate that AS-IV plays a neuroprotective role in SIVD by suppressing oxidative stress and increasing the number of mature oligodendrocytes via the modulation of SIRT1/Nrf2 signaling. Our results support AS-IV as a potential therapeutic agent for SIVD.
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Affiliation(s)
- Jing Ma
- Department of Pharmacy, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, 200092, PR China
| | - Ting Chen
- Department of Pharmacy, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, 200092, PR China.
| | - Ranran Wang
- Department of Pharmacy, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, 200092, PR China.
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25
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Wang MW, Wu CJ, Zhang ZQ. Neurological and imaging phenotypes of adults with untreated phenylketonuria: new cases and literature review. J Neurol 2023:10.1007/s00415-023-11760-9. [PMID: 37162580 DOI: 10.1007/s00415-023-11760-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 05/02/2023] [Accepted: 05/04/2023] [Indexed: 05/11/2023]
Abstract
OBJECTIVES Phenylketonuria (PKU) is the most prevalent congenital disease of amino acid metabolism. Neurological manifestations usually complicate PKU in untreated adult patients. This study describes neurological and imaging phenotypes of adult patients with untreated PKU. METHODS We investigated a cohort of 320 unrelated adult patients with suspected genetic leukoencephalopathies using whole-exome sequencing (WES). We analyzed the phenotypic features of adult PKU patients in our cohort and summarized cases reported in the literature. RESULTS We identified 10 patients in our cohort and 12 patients in the literature, who presented with neurological manifestations and were diagnosed with PKU in adulthood. Approximately 60% of these patients had onset of clinical features in adulthood. The most common neurological symptoms of patients presenting in adulthood were cognitive disturbance and spastic paralysis, followed by vision loss, cerebellar ataxia, weakness of limbs, and seizure. This differed from that of patients presenting with PKU features in childhood, who consistently had mental retardation with various neurological complications emerging during a broad age range. Imaging findings were similar between patients presenting with clinical features in childhood compared with adulthood, comprising symmetric periventricular white matter hyperintense on T2-weighted imaging and diffusion-weighted imaging predominantly in the parietal and occipital lobes. Also, normal brain imaging and diffuse leukoencephalopathies were observed in both patient groups. CONCLUSION PKU with clinical features presenting in adulthood is an atypical subtype and should be considered during diagnosis of adults with neurological symptoms and leukoencephalopathy. DWI seems to be most helpful to distinguish patients with PKU. Additionally, we demonstrate that PKU constitutes a part (3.1%) of adult genetic leukoencephalopathies.
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Affiliation(s)
- Meng-Wen Wang
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, 350005, China
| | - Chu-Jun Wu
- Department of Neurology, Beijing Tiantan Hospital, National Clinical Research Center for Neurological Diseases, Capital Medical University, No.119 South 4Th Ring West Road, Fengtai District, Beijing, 100070, China
- China National Clinical Research Center for Neurological Diseases, Beijing, 100070, China
| | - Zai-Qiang Zhang
- Department of Neurology, Beijing Tiantan Hospital, National Clinical Research Center for Neurological Diseases, Capital Medical University, No.119 South 4Th Ring West Road, Fengtai District, Beijing, 100070, China.
- China National Clinical Research Center for Neurological Diseases, Beijing, 100070, China.
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26
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Masson MA, Nait-Oumesmar B. Emerging concepts in oligodendrocyte and myelin formation, inputs from the zebrafish model. Glia 2023; 71:1147-1163. [PMID: 36645033 DOI: 10.1002/glia.24336] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/20/2022] [Accepted: 12/29/2022] [Indexed: 01/17/2023]
Abstract
Oligodendrocytes (OLs) are the myelinating cells of the central nervous system (CNS), which are derived from OL precursor cells. Myelin insulates axons allowing the saltatory conduction of action potentials and also provides trophic and metabolic supports to axons. Interestingly, oligodendroglial cells have the capacity to sense neuronal activity, which regulates myelin sheath formation via the vesicular release of neurotransmitters. Neuronal activity-dependent regulation of myelination is mediated by specialized interaction between axons and oligodendroglia, involving both synaptic and extra-synaptic modes of communications. The zebrafish has provided key advantages for the study of the myelination process in the CNS. External development and transparent larval stages of this vertebrate specie combined with the existence of several transgenic reporter lines provided key advances in oligodendroglial cell biology, axo-glial interactions and CNS myelination. In this publication, we reviewed and discussed the most recent knowledge on OL development and myelin formation, with a focus on mechanisms regulating these fundamental biological processes in the zebrafish. Especially, we highlighted the critical function of axons and oligodendroglia modes of communications and calcium signaling in myelin sheath formation and growth. Finally, we reviewed the relevance of these knowledge's in demyelinating diseases and drug discovery of pharmacological compounds favoring myelin regeneration.
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Affiliation(s)
- Mary-Amélie Masson
- Sorbonne Université, Institut du Cerveau, Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Brahim Nait-Oumesmar
- Sorbonne Université, Institut du Cerveau, Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié-Salpêtrière, Paris, France
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27
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Macintosh J, Michell-Robinson M, Chen X, Bernard G. Decreased RNA polymerase III subunit expression leads to defects in oligodendrocyte development. Front Neurosci 2023; 17:1167047. [PMID: 37179550 PMCID: PMC10167296 DOI: 10.3389/fnins.2023.1167047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 03/31/2023] [Indexed: 05/15/2023] Open
Abstract
Introduction RNA polymerase III (Pol III) is a critical enzymatic complex tasked with the transcription of ubiquitous non-coding RNAs including 5S rRNA and all tRNA genes. Despite the constitutive nature of this enzyme, hypomorphic biallelic pathogenic variants in genes encoding subunits of Pol III lead to tissue-specific features and cause a hypomyelinating leukodystrophy, characterized by a severe and permanent deficit in myelin. The pathophysiological mechanisms in POLR3- related leukodystrophy and specifically, how reduced Pol III function impacts oligodendrocyte development to account for the devastating hypomyelination seen in the disease, remain poorly understood. Methods In this study, we characterize how reducing endogenous transcript levels of leukodystrophy-associated Pol III subunits affects oligodendrocyte maturation at the level of their migration, proliferation, differentiation, and myelination. Results Our results show that decreasing Pol III expression altered the proliferation rate of oligodendrocyte precursor cells but had no impact on migration. Additionally, reducing Pol III activity impaired the differentiation of these precursor cells into mature oligodendrocytes, evident at both the level of OL-lineage marker expression and on morphological assessment, with Pol III knockdown cells displaying a drastically more immature branching complexity. Myelination was hindered in the Pol III knockdown cells, as determined in both organotypic shiverer slice cultures and co-cultures with nanofibers. Analysis of Pol III transcriptional activity revealed a decrease in the expression of distinct tRNAs, which was significant in the siPolr3a condition. Discussion In turn, our findings provide insight into the role of Pol III in oligodendrocyte development and shed light on the pathophysiological mechanisms of hypomyelination in POLR3-related leukodystrophy.
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Affiliation(s)
- Julia Macintosh
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, QC, Canada
| | - Mackenzie Michell-Robinson
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, QC, Canada
| | - Xiaoru Chen
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, QC, Canada
| | - Geneviève Bernard
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, QC, Canada
- Department of Pediatrics, McGill University, Montreal, QC, Canada
- Department of Human Genetics, McGill University, Montreal, QC, Canada
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, QC, Canada
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28
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Quental R, Sampaio M, Alonso I, Quental S, Leão M, Sousa R. A Novel Homozygous Splice Site Variant in AIMP1 Gene Causing Hypomyelinating Leukodystrophy: Case Report and Review of the Literature. Neuropediatrics 2023; 54:120-125. [PMID: 36652953 DOI: 10.1055/s-0042-1760366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND Biallelic pathogenic variants in AIMP1 gene cause hypomyelinating leukodystrophy type 3, a severe neurodegenerative disorder with early onset characterized by microcephaly, axial hypotonia, epilepsy, spasticity, and developmental delay. METHODS Clinical exome sequence was performed on patient's DNA and Sanger sequencing was used to confirm the candidate variant. To better characterize the effect of the genetic variant, functional analysis based on Sanger sequencing of the proband's complementary DNA (cDNA) was performed. RESULTS We report a case of 2-year-old girl with microcephaly, significant global developmental delay, refractory epilepsy, flaccid paralysis, hypomyelination, leukodystrophy, and cerebral atrophy on brain magnetic resonance imaging (MRI). Clinical exome sequencing revealed a novel splice site variant c.603 + 1G > A in homozygosity in the AIMP1 gene. Studies on patient's cDNA showed that the variant disrupts the canonical donor splice site of intron 5, with the recognition of a cryptic splice site within exon 5, leading to the skipping of the last 24 nucleotides of this exon together with the flanking intron. This alteration is predicted to cause an in-frame deletion of eight amino acids (p.Val194_Gln201del) belonging to the tRNA-biding domain of the protein. CONCLUSION To the best of our knowledge, this is the first report of a splice site variant in the AIMP1 gene causing hypomyelinating leukodystrophy. The description of this patient not only expands the mutational spectrum of AIMP1 but also provides deeper insights on genotype-phenotype correlation by comparing the clinical features of our patient with previously reported affected individuals.
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Affiliation(s)
- Rita Quental
- Department of Medical Genetics, Centro Hospitalar Universitário de São João, Porto, Portugal
| | - Mafalda Sampaio
- Department of Neuropediatrics, Centro Hospitalar Universitário de São João, Porto, Portugal
| | - Isabel Alonso
- Genetyca-ICM, Instituto de Estudos Celulares e Moleculares, Porto, Portugal
| | - Sofia Quental
- IPATIMUP - Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal.,Institute for Investigation and Innovation in Health (i3S), University of Porto, Porto, Portugal
| | - Miguel Leão
- Department of Medical Genetics, Centro Hospitalar Universitário de São João, Porto, Portugal
| | - Raquel Sousa
- Department of Neuropediatrics, Centro Hospitalar Universitário de São João, Porto, Portugal
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29
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Ng NS, Newbery M, Touffu A, Maksour S, Chung J, Carroll L, Zaw T, Wu Y, Ooi L. Edaravone and mitochondrial transfer as potential therapeutics for vanishing white matter disease astrocyte dysfunction. CNS Neurosci Ther 2023. [PMID: 36971196 PMCID: PMC10401142 DOI: 10.1111/cns.14190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 02/23/2023] [Accepted: 03/15/2023] [Indexed: 03/29/2023] Open
Abstract
INTRODUCTION Previous research has suggested that vanishing white matter disease (VWMD) astrocytes fail to fully differentiate and respond differently to cellular stresses compared to healthy astrocytes. However, few studies have investigated potential VWMD therapeutics in monoculture patient-derived cell-based models. METHODS To investigate the impact of alterations in astrocyte expression and function in VWMD, astrocytes were differentiated from patient and control induced pluripotent stem cells and analyzed by proteomics, pathway analysis, and functional assays, in the absence and presence of stressors or potential therapeutics. RESULTS Vanishing white matter disease astrocytes demonstrated significantly reduced expression of astrocyte markers and markers of inflammatory activation or cellular stress relative to control astrocytes. These alterations were identified both in the presence and absence of polyinosinic:polycytidylic acid stimuli, which is used to simulate viral infections. Pathway analysis highlighted differential signaling in multiple pathways in VWMD astrocytes, including eukaryotic initiation factor 2 (EIF2) signaling, oxidative stress, oxidative phosphorylation (OXPHOS), mitochondrial function, the unfolded protein response (UPR), phagosome regulation, autophagy, ER stress, tricarboxylic acid cycle (TCA) cycle, glycolysis, tRNA signaling, and senescence pathways. Since oxidative stress and mitochondrial function were two of the key pathways affected, we investigated whether two independent therapeutic strategies could ameliorate astrocyte dysfunction: edaravone treatment and mitochondrial transfer. Edaravone treatment reduced differential VWMD protein expression of the UPR, phagosome regulation, ubiquitination, autophagy, ER stress, senescence, and TCA cycle pathways. Meanwhile, mitochondrial transfer decreased VWMD differential expression of the UPR, glycolysis, calcium transport, phagosome formation, and ER stress pathways, while further modulating EIF2 signaling, tRNA signaling, TCA cycle, and OXPHOS pathways. Mitochondrial transfer also increased the gene and protein expression of the astrocyte marker, glial fibrillary acidic protein (GFAP) in VWMD astrocytes. CONCLUSION This study provides further insight into the etiology of VWMD astrocytic failure and suggests edaravone and mitochondrial transfer as potential candidate VWMD therapeutics that can ameliorate disease pathways in astrocytes related to oxidative stress, mitochondrial dysfunction, and proteostasis.
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30
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Zlomuzica A, Plank L, Kodzaga I, Dere E. A fatal alliance: Glial connexins, myelin pathology and mental disorders. J Psychiatr Res 2023; 159:97-115. [PMID: 36701970 DOI: 10.1016/j.jpsychires.2023.01.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/02/2023] [Accepted: 01/09/2023] [Indexed: 01/12/2023]
Abstract
Mature oligodendrocytes are myelin forming glial cells which are responsible for myelination of neuronal axons in the white matter of the central nervous system. Myelin pathology is a major feature of severe neurological disorders. Oligodendrocyte-specific gene mutations and/or white matter alterations have also been addressed in a variety of mental disorders. Breakdown of myelin integrity and demyelination is associated with severe symptoms, including impairments in motor coordination, breathing, dysarthria, perception (vision and hearing), and cognition. Furthermore, there is evidence indicating that myelin sheath defects and white matter pathology contributes to the affective and cognitive symptoms of patients with mental disorders. Oligodendrocytes express the connexins GJC2; mCx47 [human (GJC2) and mouse (mCx47) connexin gene nomenclature according to Söhl and Willecke (2003)], GJB1; mCx32, and GJD1; mCx29 in both white and gray matter. Preclinical findings indicate that alterations in connexin expression in oligodendrocytes and astrocytes can induce myelin defects. GJC2; mCx47 is expressed at early embryonic stages in oligodendrocyte precursors cells which precedes central nervous system myelination. In adult humans and animals GJC2, respectively mCx47 expression is essential for oligodendrocyte function and ensures adequate myelination as well as myelin maintenance in the central nervous system. In the past decade, evidence has accumulated suggesting that mental disorders can be accompanied by changes in connexin expression, myelin sheath defects and corresponding white matter alterations. This dual pathology could compromise inter-neuronal information transfer, processing and communication and eventually contribute to behavioral, sensory-motor, affective and cognitive symptoms in patients with mental disorders. The induction of myelin repair and remyelination in the central nervous system of patients with mental disorders could help to restore normal neuronal information propagation and ameliorate behavioral and cognitive symptoms in individuals with mental disorders.
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Affiliation(s)
- Armin Zlomuzica
- Department of Behavioral and Clinical Neuroscience, Ruhr-University Bochum (RUB), Massenbergstraße 9-13, D-44787, Bochum, Germany.
| | - Laurin Plank
- Department of Behavioral and Clinical Neuroscience, Ruhr-University Bochum (RUB), Massenbergstraße 9-13, D-44787, Bochum, Germany
| | - Iris Kodzaga
- Department of Behavioral and Clinical Neuroscience, Ruhr-University Bochum (RUB), Massenbergstraße 9-13, D-44787, Bochum, Germany
| | - Ekrem Dere
- Department of Behavioral and Clinical Neuroscience, Ruhr-University Bochum (RUB), Massenbergstraße 9-13, D-44787, Bochum, Germany; Sorbonne Université, UFR des Sciences de la Vie, 9 quai Saint Bernard, F-75005, Paris, France.
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31
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Steyer AM, Buscham TJ, Lorenz C, Hümmert S, Eichel-Vogel MA, Schadt LC, Edgar JM, Köster S, Möbius W, Nave KA, Werner HB. Focused ion beam-scanning electron microscopy links pathological myelin outfoldings to axonal changes in mice lacking Plp1 or Mag. Glia 2023; 71:509-523. [PMID: 36354016 DOI: 10.1002/glia.24290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 10/10/2022] [Accepted: 10/17/2022] [Indexed: 11/11/2022]
Abstract
Healthy myelin sheaths consist of multiple compacted membrane layers closely encasing the underlying axon. The ultrastructure of CNS myelin requires specialized structural myelin proteins, including the transmembrane-tetraspan proteolipid protein (PLP) and the Ig-CAM myelin-associated glycoprotein (MAG). To better understand their functional relevance, we asked to what extent the axon/myelin-units display similar morphological changes if PLP or MAG are lacking. We thus used focused ion beam-scanning electron microscopy (FIB-SEM) to re-investigate axon/myelin-units side-by-side in Plp- and Mag-null mutant mice. By three-dimensional reconstruction and morphometric analyses, pathological myelin outfoldings extend up to 10 μm longitudinally along myelinated axons in both models. More than half of all assessed outfoldings emerge from internodal myelin. Unexpectedly, three-dimensional reconstructions demonstrated that both models displayed complex axonal pathology underneath the myelin outfoldings, including axonal sprouting. Axonal anastomosing was additionally observed in Plp-null mutant mice. Importantly, normal-appearing axon/myelin-units displayed significantly increased axonal diameters in both models according to quantitative assessment of electron micrographs. These results imply that healthy CNS myelin sheaths facilitate normal axonal diameters and shape, a function that is impaired when structural myelin proteins PLP or MAG are lacking.
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Affiliation(s)
- Anna M Steyer
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Electron Microscopy-City Campus, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Tobias J Buscham
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Charlotta Lorenz
- Institute for X-Ray Physics, University of Göttingen, Göttingen, Germany
| | - Sophie Hümmert
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Maria A Eichel-Vogel
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Leonie C Schadt
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Julia M Edgar
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Sarah Köster
- Institute for X-Ray Physics, University of Göttingen, Göttingen, Germany.,Cluster of Excellence 'Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells' (MBExC), University of Göttingen, Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Electron Microscopy-City Campus, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Cluster of Excellence 'Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells' (MBExC), University of Göttingen, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
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32
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Macintosh J, Thiffault I, Pastinen T, Sztriha L, Bernard G. A Recurrent De Novo Variant in EIF2AK2 Causes a Hypomyelinating Leukodystrophy. Child Neurol Open 2023; 10:2329048X231176673. [PMID: 37284702 PMCID: PMC10240855 DOI: 10.1177/2329048x231176673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 03/29/2023] [Accepted: 05/01/2023] [Indexed: 06/08/2023] Open
Abstract
De novo pathogenic variants in EIF2AK2 have recently been reported as a novel genetic cause of leukoencephalopathy. Here, we describe a male individual who presented in the first year of life with clinical features resembling Pelizaeus-Merzbacher disease (PMD), including nystagmus, hypotonia, and global developmental delay, and which later progressed to include ataxia and spasticity. Brain MRI at the age of two revealed diffuse hypomyelination. This report adds to the limited number of individuals published and further reinforces de novo variants in EIF2AK2 as a molecular cause of a leukodystrophy that clinically and radiologically resembles PMD.
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Affiliation(s)
- Julia Macintosh
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, QC, Canada
| | - Isabelle Thiffault
- Genomic Medicine Center, Children’s Mercy Hospital, Kansas City, MO, USA
- University of Missouri Kansas City School of Medicine, Kansas City, MO, USA
- Department of Pathology and Laboratory Medicine, Children's Mercy Hospital, Kansas City, MO, USA
| | - Tomi Pastinen
- Genomic Medicine Center, Children’s Mercy Hospital, Kansas City, MO, USA
- University of Missouri Kansas City School of Medicine, Kansas City, MO, USA
- Department of Pediatrics, Children's Mercy Hospital, Kansas City, MO, USA
| | - László Sztriha
- Department of Pediatrics Szent-Györgyi Albert Medical Center, University of Szeged, Szeged, Hungary
| | - Geneviève Bernard
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, QC, Canada
- Department Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, QC, Canada
- Department of Pediatrics, McGill University, Montreal, QC, Canada
- Department of Human Genetics, McGill University, Montreal, QC, Canada
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33
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Alotaibi L, Alqasmi A. Identification of a de novo Mutation in TMEM106B in a Saudi Child Causes Hypomyelination Leukodystrophy. Glob Med Genet 2023; 10:38-41. [PMID: 36950148 PMCID: PMC10027483 DOI: 10.1055/s-0043-1764370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2023] Open
Abstract
Hypomyelinating leukodystrophies are one of the white matter disorders caused by a lack of myelin deposition in the central nervous system (CNS). Here, we report the first case of hypomyelinating leukodystrophy in the Middle East and Saudi Arabia. This condition is caused by a mutation in the TMEM106B gene (HLD16; MIM 617964). Hypotonia, congenital nystagmus, delayed motor development, and delayed speech are the main clinical manifestations. The affected patient has mild pyramidal syndrome, a mild intellectual disability, ataxic gait, hyperreflexia, intention tremor, dysmetria, and other motor difficulties. Findings from neuroimaging reveal severe, ongoing, and diffuse hypomyelination identified via the whole exome sequencing, a harmful missense mutation in the TMEM106B gene that is heterozygous. The patient is the offspring of two unrelated persons. The protein's cytoplasmic domain contains a variation that is located in highly conserved residues. In an oligodendroglial cell line, the mutant protein significantly lowered the mRNA production of important myelin genes, decreased branching, and increased cell mortality. TMEM106B is abundantly expressed in neurons and oligodendrocytes in the CNS and is localized in the late endosome and lysosome compartments. TMEM106B levels can be controlled at the transcriptional level through chromatin modification, at the mRNA level through miRNAs, and at the protein level through lysosomal functions. Our findings reveal a novel role of zinc homeostasis in oligodendrocyte development and myelin production and show that variations in TMEM163 induce hypomyelination leukodystrophy.
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Affiliation(s)
- Lena Alotaibi
- Collage of Medicine, King Saud bin Abdul-Aziz University for Health Sciences, Riyadh, Saudi Arabia
- Address for correspondence Leena fahad Alotaibi College of Medicine, King Saud bin Abdulaziz University for Health SciencesRiyadhSaudi Arabia
| | - Amal Alqasmi
- Department of Pediatric Neurology and Epilepsy, King Saud Medical City, Riyadh, Saudi Arabia
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34
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do Rosario MC, Bey GR, Nmezi B, Liu F, Oranburg T, Cohen ASA, Coffman KA, Brown MR, Kiselyov K, Waisfisz Q, Flohil MT, Siddiqui S, Rosenfeld JA, Iglesias A, Girisha KM, Wolf NI, Padiath QS, Shukla A. Variants in the zinc transporter TMEM163 cause a hypomyelinating leukodystrophy. Brain 2022; 145:4202-4209. [PMID: 35953447 PMCID: PMC10200305 DOI: 10.1093/brain/awac295] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 07/12/2022] [Accepted: 07/31/2022] [Indexed: 11/12/2022] Open
Abstract
Hypomyelinating leukodystrophies comprise a subclass of genetic disorders with deficient myelination of the CNS white matter. Here we report four unrelated families with a hypomyelinating leukodystrophy phenotype harbouring variants in TMEM163 (NM_030923.5). The initial clinical presentation resembled Pelizaeus-Merzbacher disease with congenital nystagmus, hypotonia, delayed global development and neuroimaging findings suggestive of significant and diffuse hypomyelination. Genomic testing identified three distinct heterozygous missense variants in TMEM163 with two unrelated individuals sharing the same de novo variant. TMEM163 is highly expressed in the CNS particularly in newly myelinating oligodendrocytes and was recently revealed to function as a zinc efflux transporter. All the variants identified lie in highly conserved residues in the cytoplasmic domain of the protein, and functional in vitro analysis of the mutant protein demonstrated significant impairment in the ability to efflux zinc out of the cell. Expression of the mutant proteins in an oligodendroglial cell line resulted in substantially reduced mRNA expression of key myelin genes, reduced branching and increased cell death. Our findings indicate that variants in TMEM163 cause a hypomyelinating leukodystrophy and uncover a novel role for zinc homeostasis in oligodendrocyte development and myelin formation.
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Affiliation(s)
- Michelle C do Rosario
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Guillermo Rodriguez Bey
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Bruce Nmezi
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Fang Liu
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Talia Oranburg
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Ana S A Cohen
- Genomic Medicine Center, Children’s Mercy, Kansas City, MO 64108, USA
- Department of Pathology and Laboratory Medicine, Children’s Mercy, Kansas City, MO 64108, USA
- School of Medicine Serves, University of Missouri-Kansas City School of Medicine, Kansas City, MO 64108, USA
| | - Keith A Coffman
- Division of Neurology, Movement Disorders Clinic, Tourette Syndrome Center of Excellence, Children’s Mercy Hospital, Kansas City, Missouri, USA
| | - Maya R Brown
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Kirill Kiselyov
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Quinten Waisfisz
- Department of Human Genetics, Amsterdam University Medical Centers, VU University Amsterdam, and Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Myrthe T Flohil
- Department of Neurology, Noordwest ziekenhuisgroep, Wilhelminalaan Alkmaar, The Netherlands
| | - Shahyan Siddiqui
- Department of Neuroimaging and Interventional Radiology, STAR Institute of Neurosciences, STAR Hospitals, Hyderabad, India
| | - Jill A Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- Baylor Genetics Laboratories, Houston, Texas, USA
| | - Alejandro Iglesias
- Department of Pediatrics, Columbia University Irving Medical Center, New York, New York, USA
| | - Katta Mohan Girisha
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Nicole I Wolf
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Department of Child Neurology, Amsterdam Leukodystrophy Center, Emma’s Children’s Hospital, and Amsterdam Neuroscience, Cellular & Molecular Mechanisms, Amsterdam, The Netherlands
| | - Quasar Saleem Padiath
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Neurobiology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Anju Shukla
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
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35
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Hypomyelinating Leukodystrophy 10 (HLD10)-Associated Mutations of PYCR2 Form Large Size Mitochondria, Inhibiting Oligodendroglial Cell Morphological Differentiation. Neurol Int 2022; 14:1062-1080. [PMID: 36548190 PMCID: PMC9787162 DOI: 10.3390/neurolint14040085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 12/08/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
Hypomyelinating leukodystrophy 10 (HLD10) is an autosomal recessive disease related to myelin sheaths in the central nervous system (CNS). In the CNS, myelin sheaths are derived from differentiated plasma membranes of oligodendrocytes (oligodendroglial cells) and surround neuronal axons to achieve neuronal functions. Nucleotide mutations of the pyrroline-5-carboxylate reductase 2 (PYCR2) gene are associated with HLD10, likely due to PYCR2's loss-of-function. PYCR2 is a mitochondrial residential protein and catalyzes pyrroline-5-carboxylate to an amino acid proline. Here, we describe how each of the HLD10-associated missense mutations, Arg119-to-Cys [R119C] and Arg251-to-Cys [R251C], lead to forming large size mitochondria in the FBD-102b cell line, which is used as an oligodendroglial cell differentiation model. In contrast, the wild type proteins did not participate in the formation of large size mitochondria. Expression of each of the mutated R119C and R251C proteins in cells increased the fusion abilities in mitochondria and decreased their fission abilities relatively. The respective mutant proteins, but not wild type proteins also decreased the activities of mitochondria. While cells expressing the wild type proteins exhibited differentiated phenotypes with widespread membranes and increased expression levels of differentiation marker proteins following the induction of differentiation, cells harboring each of the mutant proteins did not. Taken together, these results indicate that an HLD10-associated PYCR2 mutation leads to the formation of large mitochondria with decreased activities, inhibiting oligodendroglial cell morphological differentiation. These results may reveal some of the pathological mechanisms in oligodendroglial cells underlying HLD10 at the molecular and cellular levels.
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36
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Martin S, Allan KC, Pinkard O, Sweet T, Tesar PJ, Coller J. Oligodendrocyte differentiation alters tRNA modifications and codon optimality-mediated mRNA decay. Nat Commun 2022; 13:5003. [PMID: 36008413 PMCID: PMC9411196 DOI: 10.1038/s41467-022-32766-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 08/15/2022] [Indexed: 11/08/2022] Open
Abstract
Oligodendrocytes are specialized cells that confer neuronal myelination in the central nervous system. Leukodystrophies associated with oligodendrocyte deficits and hypomyelination are known to result when a number of tRNA metabolism genes are mutated. Thus, for unknown reasons, oligodendrocytes may be hypersensitive to perturbations in tRNA biology. In this study, we survey the tRNA transcriptome in the murine oligodendrocyte cell lineage and find that specific tRNAs are hypomodified in oligodendrocytes within or near the anticodon compared to oligodendrocyte progenitor cells (OPCs). This hypomodified state may be the result of differential expression of key modification enzymes during oligodendrocyte differentiation. Moreover, we observe a concomitant relationship between tRNA hypomodification and tRNA decoding potential; observing oligodendrocyte specific alterations in codon optimality-mediated mRNA decay and ribosome transit. Our results reveal that oligodendrocytes naturally maintain a delicate, hypersensitized tRNA/mRNA axis. We suggest this axis is a potential mediator of pathology in leukodystrophies and white matter disease when further insult to tRNA metabolism is introduced.
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Affiliation(s)
- Sophie Martin
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Kevin C Allan
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Otis Pinkard
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Thomas Sweet
- Center for Proteomics and Bioinformatics, Department of Nutrition, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Paul J Tesar
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Jeff Coller
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Department of Biology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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Cheng N, Li G, Kanchwala M, Evers BM, Xing C, Yu H. STAG2 promotes the myelination transcriptional programin oligodendrocytes. eLife 2022; 11:77848. [PMID: 35959892 PMCID: PMC9439679 DOI: 10.7554/elife.77848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 08/11/2022] [Indexed: 11/13/2022] Open
Abstract
Cohesin folds chromosomes via DNA loop extrusion. Cohesin-mediated chromosome loops regulate transcription by shaping long-range enhancer-promoter interactions, among other mechanisms. Mutations of cohesin subunits and regulators cause human developmental diseases termed cohesinopathy. Vertebrate cohesin consists of SMC1, SMC3, RAD21, and either STAG1 or STAG2. To probe the physiological functions of cohesin, we created conditional knockout (cKO) mice with Stag2 deleted in the nervous system. Stag2 cKO mice exhibit growth retardation, neurological defects, and premature death, in part due to insufficient myelination of nerve fibers. Stag2 cKO oligodendrocytes exhibit delayed maturation and downregulation of myelination-related genes. Stag2 loss reduces promoter-anchored loops at downregulated genes in oligodendrocytes. Thus, STAG2-cohesin generates promoter-anchored loops at myelination-promoting genes to facilitate their transcription. Our study implicates defective myelination as a contributing factor to cohesinopathy and establishes oligodendrocytes as a relevant cell type to explore the mechanisms by which cohesin regulates transcription.
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Affiliation(s)
- Ningyan Cheng
- Department of Pharmacology, The University of Texas Southwestern Medical Center, Dallas, United States
| | - Guanchen Li
- School of Life Sciences, Westlake University, Hangzhou, China
| | - Mohammed Kanchwala
- Eugene McDermott Center for Human Growth and Development, The University of Texas Southwestern Medical Center, Dallas, United States
| | - Bret M Evers
- Division of Neuropathology, The University of Texas Southwestern Medical Center, Dallas, United States
| | - Chao Xing
- Eugene McDermott Center for Human Growth and Development, The University of Texas Southwestern Medical Center, Dallas, United States
| | - Hongtao Yu
- Westlake Laboratory of Life Sciences and Biomedicine, Westlake University, Hangzhou, Zhejiang Province, China
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Nowacki JC, Fields AM, Fu MM. Emerging cellular themes in leukodystrophies. Front Cell Dev Biol 2022; 10:902261. [PMID: 36003149 PMCID: PMC9393611 DOI: 10.3389/fcell.2022.902261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 06/30/2022] [Indexed: 11/18/2022] Open
Abstract
Leukodystrophies are a broad spectrum of neurological disorders that are characterized primarily by deficiencies in myelin formation. Clinical manifestations of leukodystrophies usually appear during childhood and common symptoms include lack of motor coordination, difficulty with or loss of ambulation, issues with vision and/or hearing, cognitive decline, regression in speech skills, and even seizures. Many cases of leukodystrophy can be attributed to genetic mutations, but they have diverse inheritance patterns (e.g., autosomal recessive, autosomal dominant, or X-linked) and some arise from de novo mutations. In this review, we provide an updated overview of 35 types of leukodystrophies and focus on cellular mechanisms that may underlie these disorders. We find common themes in specialized functions in oligodendrocytes, which are specialized producers of membranes and myelin lipids. These mechanisms include myelin protein defects, lipid processing and peroxisome dysfunction, transcriptional and translational dysregulation, disruptions in cytoskeletal organization, and cell junction defects. In addition, non-cell-autonomous factors in astrocytes and microglia, such as autoimmune reactivity, and intercellular communication, may also play a role in leukodystrophy onset. We hope that highlighting these themes in cellular dysfunction in leukodystrophies may yield conceptual insights on future therapeutic approaches.
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Adang L. Leukodystrophies. Continuum (Minneap Minn) 2022; 28:1194-1216. [PMID: 35938662 DOI: 10.1212/con.0000000000001130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE OF REVIEW This article reviews the most common leukodystrophies and is focused on diagnosis, clinical features, and emerging therapeutic options. RECENT FINDINGS In the past decade, the recognition of leukodystrophies has exponentially increased, and now this class includes more than 30 distinct disorders. Classically recognized as progressive and fatal disorders affecting young children, it is now understood that leukodystrophies are associated with an increasing spectrum of neurologic trajectories and can affect all ages. Next-generation sequencing and newborn screening allow the opportunity for the recognition of presymptomatic and atypical cases. These new testing opportunities, in combination with growing numbers of natural history studies and clinical consensus guidelines, have helped improve diagnosis and clinical care. Additionally, a more granular understanding of disease outcomes informs clinical trial design and has led to several recent therapeutic advances. This review summarizes the current understanding of the clinical manifestations of disease and treatment options for the most common leukodystrophies. SUMMARY As early testing becomes more readily available through next-generation sequencing and newborn screening, neurologists will better understand the true incidence of the leukodystrophies and be able to diagnose children within the therapeutic window. As targeted therapies are developed, it becomes increasingly imperative that this broad spectrum of disorders is recognized and diagnosed. This work summarizes key advances in the leukodystrophy field.
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Khalaf G, Mattern C, Begou M, Boespflug-Tanguy O, Massaad C, Massaad-Massade L. Mutation of Proteolipid Protein 1 Gene: From Severe Hypomyelinating Leukodystrophy to Inherited Spastic Paraplegia. Biomedicines 2022; 10:biomedicines10071709. [PMID: 35885014 PMCID: PMC9313024 DOI: 10.3390/biomedicines10071709] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 07/06/2022] [Accepted: 07/12/2022] [Indexed: 01/17/2023] Open
Abstract
Pelizaeus–Merzbacher Disease (PMD) is an inherited leukodystrophy affecting the central nervous system (CNS)—a rare disorder that especially concerns males. Its estimated prevalence is 1.45–1.9 per 100,000 individuals in the general population. Patients affected by PMD exhibit a drastic reduction or absence of myelin sheaths in the white matter areas of the CNS. The Proteolipid Protein 1 (PLP1) gene encodes a transmembrane proteolipid protein. PLP1 is the major protein of myelin, and it plays a key role in the compaction, stabilization, and maintenance of myelin sheaths. Its function is predominant in oligodendrocyte development and axonal survival. Mutations in the PLP1 gene cause the development of a wide continuum spectrum of leukopathies from the most severe form of PMD for whom patients exhibit severe CNS hypomyelination to the relatively mild late-onset type 2 spastic paraplegia, leading to the concept of PLP1-related disorders. The genetic diversity and the biochemical complexity, along with other aspects of PMD, are discussed to reveal the obstacles that hinder the development of treatments. This review aims to provide a clinical and mechanistic overview of this spectrum of rare diseases.
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Affiliation(s)
- Guy Khalaf
- U1195 Diseases and Hormones of the Nervous System, INSERM and Université Paris-Saclay, 94276 Le Kremlin-Bicêtre, France;
| | | | - Mélina Begou
- Neuro-Dol, CNRS, Inserm, Université Clermont Auvergne, 63000 Clermont-Ferrand, France;
| | - Odile Boespflug-Tanguy
- UMR 1141, INSERM, NeuroDiderot Université Paris Cité and APH-P, Neuropédiatrie, French Reference Center for Leukodystrophies, LEUKOFRANCE, Hôpital Robert Debré, 75019 Paris, France;
| | - Charbel Massaad
- UMRS 1124, INSERM, Université Paris Cité, 75006 Paris, France
- Correspondence: (C.M.); (L.M.-M.);Tel.: +33-1-49-59-18-30 (L.M.-M.)
| | - Liliane Massaad-Massade
- U1195 Diseases and Hormones of the Nervous System, INSERM and Université Paris-Saclay, 94276 Le Kremlin-Bicêtre, France;
- Correspondence: (C.M.); (L.M.-M.);Tel.: +33-1-49-59-18-30 (L.M.-M.)
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41
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Stutterd CA, Vanderver A, Lockhart PJ, Helman G, Pope K, Uebergang E, Love C, Delatycki MB, Thorburn D, Mackay MT, Peters H, Kornberg AJ, Patel C, Rodriguez-Casero V, Waak M, Silberstein J, Sinclair A, Nolan M, Field M, Davis MR, Fahey M, Scheffer IE, Freeman JL, Wolf NI, Taft RJ, van der Knaap MS, Simons C, Leventer RJ. Unclassified white matter disorders: A diagnostic journey requiring close collaboration between clinical and laboratory services. Eur J Med Genet 2022; 65:104551. [PMID: 35803560 DOI: 10.1016/j.ejmg.2022.104551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 05/27/2022] [Accepted: 06/18/2022] [Indexed: 11/26/2022]
Abstract
BACKGROUND Next generation sequencing studies have revealed an ever-increasing number of causes for genetic disorders of central nervous system white matter. A substantial number of disorders are identifiable from their specific pattern of biochemical and/or imaging findings for which single gene testing may be indicated. Beyond this group, the causes of genetic white matter disorders are unclear and a broader approach to genomic testing is recommended. AIM This study aimed to identify the genetic causes for a group of individuals with unclassified white matter disorders with suspected genetic aetiology and highlight the investigations required when the initial testing is non-diagnostic. METHODS Twenty-six individuals from 22 families with unclassified white matter disorders underwent deep phenotyping and genome sequencing performed on trio, or larger, family groups. Functional studies and transcriptomics were used to resolve variants of uncertain significance with potential clinical relevance. RESULTS Causative or candidate variants were identified in 15/22 (68.2%) families. Six of the 15 implicated genes had been previously associated with white matter disease (COL4A1, NDUFV1, SLC17A5, TUBB4A, BOLA3, DARS2). Patients with variants in the latter two presented with an atypical phenotype. The other nine genes had not been specifically associated with white matter disease at the time of diagnosis and included genes associated with monogenic syndromes, developmental disorders, and developmental and epileptic encephalopathies (STAG2, LSS, FIG4, GLS, PMPCA, SPTBN1, AGO2, SCN2A, SCN8A). Consequently, only 46% of the diagnoses would have been made via a current leukodystrophy gene panel test. DISCUSSION These results confirm the importance of broad genomic testing for patients with white matter disorders. The high diagnostic yield reflects the integration of deep phenotyping, whole genome sequencing, trio analysis, functional studies, and transcriptomic analyses. CONCLUSIONS Genetic white matter disorders are genetically and phenotypically heterogeneous. Deep phenotyping together with a range of genomic technologies underpin the identification of causes of unclassified white matter disease. A molecular diagnosis is essential for prognostication, appropriate management, and accurate reproductive counseling.
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Affiliation(s)
- C A Stutterd
- Murdoch Children's Research Institute, Victoria, Australia; Department of Neurology, Royal Children's Hospital, Victoria, Australia; Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Victoria, Australia; Department of Paediatrics, University of Melbourne, Victoria, Australia
| | - A Vanderver
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA; Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - P J Lockhart
- Murdoch Children's Research Institute, Victoria, Australia; Department of Paediatrics, University of Melbourne, Victoria, Australia
| | - G Helman
- Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland, Australia
| | - K Pope
- Murdoch Children's Research Institute, Victoria, Australia
| | - E Uebergang
- Murdoch Children's Research Institute, Victoria, Australia
| | - C Love
- Murdoch Children's Research Institute, Victoria, Australia
| | - M B Delatycki
- Murdoch Children's Research Institute, Victoria, Australia; Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Victoria, Australia; Department of Paediatrics, University of Melbourne, Victoria, Australia
| | - D Thorburn
- Murdoch Children's Research Institute, Victoria, Australia; Department of Paediatrics, University of Melbourne, Victoria, Australia
| | - M T Mackay
- Murdoch Children's Research Institute, Victoria, Australia; Department of Neurology, Royal Children's Hospital, Victoria, Australia; Department of Paediatrics, University of Melbourne, Victoria, Australia
| | - H Peters
- Murdoch Children's Research Institute, Victoria, Australia; Department of Paediatrics, University of Melbourne, Victoria, Australia; Department of Metabolic Medicine, Royal Children's Hospital, Victoria, Australia
| | - A J Kornberg
- Murdoch Children's Research Institute, Victoria, Australia; Department of Neurology, Royal Children's Hospital, Victoria, Australia; Department of Paediatrics, University of Melbourne, Victoria, Australia
| | - C Patel
- Genetic Health Queensland, Royal Brisbane and Women's Children's Hospital, South Brisbane Queensland, Australia; Centre for Children's Health Research, The University of Queensland, Queensland, Australia
| | - V Rodriguez-Casero
- Murdoch Children's Research Institute, Victoria, Australia; Department of Neurology, Royal Children's Hospital, Victoria, Australia; Department of Paediatrics, University of Melbourne, Victoria, Australia
| | - M Waak
- Centre for Children's Health Research, The University of Queensland, Queensland, Australia; Department of Neurosciences, Queensland Children's Hospital, Brisbane, Queensland, Australia
| | - J Silberstein
- Princess Margaret Hospital, Perth, Western Australia, Australia
| | - A Sinclair
- Department of Neurosciences, Queensland Children's Hospital, Brisbane, Queensland, Australia
| | - M Nolan
- Department of Paediatric Neurology, Starship Children's Health, Auckland, New Zealand
| | - M Field
- Genetics of Learning Disability (GOLD) Service, Hunter Genetics, Newcastle, New South Wales, Australia
| | - M R Davis
- Department of Diagnostic Genomics, Path West Laboratory Medicine, QEII Medical Centre, Hospital Avenue, Nedlands, WA, Australia
| | - M Fahey
- Department of Paediatrics, Monash University, Victoria, Australia
| | - I E Scheffer
- Murdoch Children's Research Institute, Victoria, Australia; Department of Neurology, Royal Children's Hospital, Victoria, Australia; Department of Paediatrics, University of Melbourne, Victoria, Australia; Department of Medicine, The University of Melbourne, Austin Health, Heidelberg, Victoria, 3084, Australia; The Florey Institute of Neuroscience and Mental Health and Murdoch Children's Research Institute, Parkville, Victoria, 3052, Australia
| | - J L Freeman
- Murdoch Children's Research Institute, Victoria, Australia; Department of Neurology, Royal Children's Hospital, Victoria, Australia; Department of Paediatrics, University of Melbourne, Victoria, Australia
| | - N I Wolf
- Amsterdam Leukodystrophy Center, Department of Child Neurology, Emma Children's Hospital, Amsterdam University Medical Centers, VU University, Amsterdam Neuroscience, Amsterdam, the Netherlands; Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
| | - R J Taft
- Illumina Inc, San Diego, CA, USA
| | - M S van der Knaap
- Amsterdam Leukodystrophy Center, Department of Child Neurology, Emma Children's Hospital, Amsterdam University Medical Centers, VU University, Amsterdam Neuroscience, Amsterdam, the Netherlands; Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
| | - C Simons
- Murdoch Children's Research Institute, Victoria, Australia; Department of Paediatrics, University of Melbourne, Victoria, Australia.
| | - R J Leventer
- Murdoch Children's Research Institute, Victoria, Australia; Department of Neurology, Royal Children's Hospital, Victoria, Australia; Department of Paediatrics, University of Melbourne, Victoria, Australia.
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Missense mutation of MAL causes a rare leukodystrophy similar to Pelizaeus-Merzbacher disease. Eur J Hum Genet 2022; 30:860-864. [PMID: 35217805 PMCID: PMC9259702 DOI: 10.1038/s41431-022-01050-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 01/03/2022] [Accepted: 01/18/2022] [Indexed: 11/08/2022] Open
Abstract
Leukodystrophies are a heterogenous group of genetic disorders, characterised by abnormal development of cerebral white matter. Pelizaeus-Merzbacher disease is caused by mutations in PLP1, encoding major myelin-resident protein required for myelin sheath assembly. We report a missense variant p.(Ala109Asp) in MAL as causative for a rare, hypomyelinating leukodystrophy similar to Pelizaeus-Merzbacher disease. MAL encodes a membrane proteolipid that directly interacts with PLP1, ensuring correct distribution during myelin assembly. In contrast to wild-type MAL, mutant MAL was retained in the endoplasmic reticulum but was released following treatment with 4-phenylbutyrate. Proximity-dependent identification of wild-type MAL interactants implicated post-Golgi vesicle-mediated protein transport and protein localisation to membranes, whereas mutant MAL interactants suggested unfolded protein responses. Our results suggest that mislocalisation of MAL affects PLP1 distribution, consistent with known pathomechanisms for hypomyelinating leukodystrophies.
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43
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Komachali SR, Sheikholeslami M, Salehi M. A novel mutation in GJC2 associated with hypomyelinating leukodystrophy type 2 disorder. Genomics Inform 2022; 20:e24. [PMID: 35794704 PMCID: PMC9299563 DOI: 10.5808/gi.22008] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 04/27/2022] [Indexed: 11/30/2022] Open
Abstract
Hypomyelinating leukodystrophy type 2 (HLD2), is an inherited genetic disease of the central nervous system caused by recessive mutations in the gap junction protein gamma 2 (GJC2/GJA12). HLD2 is characterized by nystagmus, developmental delay, motor impairments, ataxia, severe speech problem, and hypomyelination in the brain. The GJC2 sequence encodes connexin 47 protein (Cx47). Connexins are a group of membrane proteins that oligomerize to construct gap junctions protein. In the present study, a novel missense mutation gene c.760G>A (p.Val254Met) was identified in a patient with HLD2 by performing whole exome sequencing. Following the discovery of the new mutation in the proband, we used Sanger sequencing to analyze his affected sibling and parents. Sanger sequencing verified homozygosity of the mutation in the proband and his affected sibling. The autosomal recessive inheritance pattern was confirmed since Sanger sequencing revealed both healthy parents were heterozygous for the mutation. PolyPhen2, SIFT, PROVEAN, and CADD were used to evaluate the function prediction scores of detected mutations. Cx47 is essential for oligodendrocyte function, including adequate myelination and myelin maintenance in humans. Novel mutation p.Val254Met is located in the second extracellular domain of Cx47, both extracellular loops are highly conserved and probably induce intramolecular disulfide interactions. This novel mutation in the Cx47 gene causes oligodendrocyte dysfunction and HLD2 disorder.
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Affiliation(s)
- Sajad Rafiee Komachali
- Department of Biology, University of Sistan and Baluchestan, Zahedan 98167-45845, Iran.,Medical Genetics Research Center of Genome, Isfahan University of Medical Sciences, Isfahan 81759-54319, Iran
| | | | - Mansoor Salehi
- Medical Genetics Research Center of Genome, Isfahan University of Medical Sciences, Isfahan 81759-54319, Iran
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44
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Lariosa-Willingham K, Leonoudakis D, Bragge T, Tolppanen L, Nurmi A, Flanagan M, Gibson J, Wilson D, Stratton J, Lehtimäki KK, Miszczuk D. An in vivo accelerated developmental myelination model for testing promyelinating therapeutics. BMC Neurosci 2022; 23:30. [PMID: 35614392 PMCID: PMC9134688 DOI: 10.1186/s12868-022-00714-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 05/10/2022] [Indexed: 12/13/2022] Open
Abstract
Background Therapeutic agents stimulating the process of myelination could be beneficial for the treatment of demyelinating diseases, such as multiple sclerosis. The efficient translation of compounds promoting myelination in vitro to efficacy in vivo is inherently time-consuming and expensive. Thyroid hormones accelerate the differentiation and maturation of oligodendrocytes, thereby promoting myelination. Systemic administration of the thyroid hormone thyroxine (T4) accelerates brain maturation, including myelination, during early postnatal development. The objective of this study was to validate an animal model for rapid testing of promyelinating therapeutic candidates for their effects on early postnatal development by using T4 as a reference compound. Methods Daily subcutaneous injections of T4 were given to Sprague Dawley rat pups from postnatal day (PND) 2 to PND10. Changes in white matter were determined at PND10 using diffusion tensor magnetic resonance imaging (DTI). Temporal changes in myelination from PND3 to PND11 were also assessed by quantifying myelin basic protein (MBP) expression levels in the brain using the resonance Raman spectroscopy/enzyme-linked immunosorbent assay (RRS-ELISA) and quantitative immunohistochemistry. Results DTI of white matter tracts showed significantly higher fractional anisotropy in the internal capsule of T4-treated rat pups. The distribution of total FA values in the forebrain was significantly shifted towards higher values in the T4-treated group, suggesting increased myelination. In vivo imaging data were supported by in vitro observations, as T4 administration significantly potentiated the developmental increase in MBP levels in brain lysates starting from PND8. MBP levels in the brain of animals that received treatment for 9 days correlated with the FA metric determined in the same pups in vivo a day earlier. Furthermore, accelerated developmental myelination following T4 administration was confirmed by immunohistochemical staining for MBP in coronal brain sections of treated rat pups. Conclusions T4-treated rat pups had increased MBP expression levels and higher MRI fractional anisotropy values, both indications of accelerated myelination. This simple developmental myelination model affords a rapid test of promyelinating activity in vivo within several days, which could facilitate in vivo prescreening of candidate therapeutic compounds for developmental hypomyelinating diseases. Further research will be necessary to assess the utility of this platform for screening promyelination compounds in more complex demyelination disease models, such us multiple sclerosis. Supplementary information The online version contains supplementary material available at 10.1186/s12868-022-00714-y.
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Affiliation(s)
| | | | - Timo Bragge
- Charles River Discovery Services, Neulaniementie 4, 70210, Kuopio, Finland
| | - Laura Tolppanen
- Charles River Discovery Services, Neulaniementie 4, 70210, Kuopio, Finland
| | - Antti Nurmi
- Charles River Discovery Services, Neulaniementie 4, 70210, Kuopio, Finland
| | | | | | - David Wilson
- Teva Pharmaceutical Industries Ltd, Redwood City, CA, 94063, USA
| | | | - Kimmo K Lehtimäki
- Charles River Discovery Services, Neulaniementie 4, 70210, Kuopio, Finland
| | - Diana Miszczuk
- Charles River Discovery Services, Neulaniementie 4, 70210, Kuopio, Finland
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45
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Guasto A, Dubail J, Aguilera-Albesa S, Paganini C, Vanhulle C, Haouari W, Gorría-Redondo N, Aznal-Sainz E, Boddaert N, Planas-Serra L, Schlüter A, Verdura E, Bruneel A, Rossi A, Huber C, Pujol A, Cormier-Daire V. Biallelic variants in SLC35B2 cause a novel chondrodysplasia with hypomyelinating leukodystrophy. Brain 2022; 145:3711-3722. [PMID: 35325049 DOI: 10.1093/brain/awac110] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 02/22/2022] [Accepted: 03/13/2022] [Indexed: 11/13/2022] Open
Abstract
Sulfated proteoglycans are essential in skeletal and brain development. Recently, pathogenic variants in genes encoding proteins involved in the proteoglycan biosynthesis have been identified in a range of chondrodysplasia associated with intellectual disability. Nevertheless, several patients remain with unidentified molecular basis. This study aimed to contribute to the deciphering of new molecular bases in patients with chondrodysplasia and neuro-developmental disease. Exome sequencing was performed to identify pathogenic variants in patients presenting with chondrodysplasia and intellectual disability. The pathogenic effects of the potentially causative variants were analyzed by functional studies. We identified homozygous variants (c.1218_1220del and c.1224_1225del) in SLC35B2 in two patients with pre- and postnatal growth retardation, scoliosis, severe motor and intellectual disabilities and hypomyelinating leukodystrophy. By functional analyses, we showed that the variants affect SLC35B2 mRNA expression and protein subcellular localization leading to a functional impairment of the protein. Consistent with those results, we detected proteoglycan sulfation impairment in SLC35B2 patient fibroblasts and serum. Our data support that SLC35B2 functional impairment causes a novel syndromic chondrodysplasia with hypomyelinating leukodystrophy, most likely through a proteoglycan sulfation defect. This is the first time that SLC35B2 variants are associated with bone and brain development in human.
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Affiliation(s)
- Alessandra Guasto
- Paris Cité University, INSERM UMR1163, Imagine Institute, 75015 Paris, France
| | - Johanne Dubail
- Paris Cité University, INSERM UMR1163, Imagine Institute, 75015 Paris, France
| | - Sergio Aguilera-Albesa
- Pediatric Neurology Unit, Department of Pediatrics, Complejo Hospitalario de Navarra, Navarrabiomed, Pamplona, Spain.,Children's Medically Complex Diseases Unit, Department of Pediatrics, Complejo Hospitalario de Navarra, Pamplona, Spain
| | - Chiara Paganini
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Pavia, Italy
| | - Catherine Vanhulle
- Service de Neuropédiatrie, pavillon Martainville, Hôpital Charles Nicolle, 76031, Rouen, France
| | - Walid Haouari
- INSERM UMR1193, Paris-Saclay University, F-92220 Châtenay-Malabry, France
| | - Nerea Gorría-Redondo
- Pediatric Neurology Unit, Department of Pediatrics, Complejo Hospitalario de Navarra, Navarrabiomed, Pamplona, Spain
| | - Elena Aznal-Sainz
- Children's Medically Complex Diseases Unit, Department of Pediatrics, Complejo Hospitalario de Navarra, Pamplona, Spain
| | - Nathalie Boddaert
- Service d'Imagerie pédiatrique, AP-HP, Hôpital Necker-Enfants malades, F-75015 Paris, France
| | - Laura Planas-Serra
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08908, Barcelona, Catalonia, Spain.,Centre for Biomedical Research in Network on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain
| | - Agatha Schlüter
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08908, Barcelona, Catalonia, Spain.,Centre for Biomedical Research in Network on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain
| | - Edgard Verdura
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08908, Barcelona, Catalonia, Spain.,Centre for Biomedical Research in Network on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain
| | - Arnaud Bruneel
- INSERM UMR1193, Paris-Saclay University, F-92220 Châtenay-Malabry, France.,AP-HP, Biochimie métabolique et cellulaire, Hôpital Bichat, F-75018, Paris, France
| | - Antonio Rossi
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Pavia, Italy
| | - Céline Huber
- Paris Cité University, INSERM UMR1163, Imagine Institute, 75015 Paris, France
| | - Aurora Pujol
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08908, Barcelona, Catalonia, Spain.,Centre for Biomedical Research in Network on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain.,Catalan Institution of Research and Advanced Studies (ICREA), Barcelona, Catalonia, Spain
| | - Valérie Cormier-Daire
- Paris Cité University, INSERM UMR1163, Imagine Institute, 75015 Paris, France.,Service de Génétique clinique, Centre de référence pour les maladies osseuses constitutionnelles, AP-HP, Hôpital Necker-Enfants malades, F-75015 Paris, France
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Buscham TJ, Eichel-Vogel MA, Steyer AM, Jahn O, Strenzke N, Dardawal R, Memhave TR, Siems SB, Müller C, Meschkat M, Sun T, Ruhwedel T, Möbius W, Krämer-Albers EM, Boretius S, Nave KA, Werner HB. Progressive axonopathy when oligodendrocytes lack the myelin protein CMTM5. eLife 2022; 11:75523. [PMID: 35274615 PMCID: PMC8916772 DOI: 10.7554/elife.75523] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 02/27/2022] [Indexed: 11/26/2022] Open
Abstract
Oligodendrocytes facilitate rapid impulse propagation along the axons they myelinate and support their long-term integrity. However, the functional relevance of many myelin proteins has remained unknown. Here, we find that expression of the tetraspan-transmembrane protein CMTM5 (chemokine-like factor-like MARVEL-transmembrane domain containing protein 5) is highly enriched in oligodendrocytes and central nervous system (CNS) myelin. Genetic disruption of the Cmtm5 gene in oligodendrocytes of mice does not impair the development or ultrastructure of CNS myelin. However, oligodendroglial Cmtm5 deficiency causes an early-onset progressive axonopathy, which we also observe in global and tamoxifen-induced oligodendroglial Cmtm5 mutants. Presence of the WldS mutation ameliorates the axonopathy, implying a Wallerian degeneration-like pathomechanism. These results indicate that CMTM5 is involved in the function of oligodendrocytes to maintain axonal integrity rather than myelin biogenesis.
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Affiliation(s)
- Tobias J Buscham
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Maria A Eichel-Vogel
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Anna M Steyer
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Electron Microscopy Core Unit, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Olaf Jahn
- Proteomics Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Translational Neuroproteomics Group, Department of Psychiatry and Psychotherapy, University Medical Center Göttingen, Georg-August-University, Göttingen, Germany
| | - Nicola Strenzke
- Institute for Auditory Neuroscience, University Medicine Göttingen, Göttingen, Germany
| | - Rakshit Dardawal
- Functional Imaging Laboratory, German Primate Center, Leibniz Institute for Primate Research, Göttingen, Germany
| | - Tor R Memhave
- Functional Imaging Laboratory, German Primate Center, Leibniz Institute for Primate Research, Göttingen, Germany
| | - Sophie B Siems
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Christina Müller
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University, Mainz, Germany
| | - Martin Meschkat
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Abberior Instruments Gmbh, Göttingen, Germany
| | - Ting Sun
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Torben Ruhwedel
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Electron Microscopy Core Unit, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Electron Microscopy Core Unit, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Eva-Maria Krämer-Albers
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University, Mainz, Germany
| | - Susann Boretius
- Functional Imaging Laboratory, German Primate Center, Leibniz Institute for Primate Research, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
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Sawaguchi S, Suzuki R, Oizumi H, Ohbuchi K, Mizoguchi K, Yamamoto M, Miyamoto Y, Yamauchi J. Hypomyelinating Leukodystrophy 8 (HLD8)-Associated Mutation of POLR3B Leads to Defective Oligodendroglial Morphological Differentiation Whose Effect Is Reversed by Ibuprofen. Neurol Int 2022; 14:212-244. [PMID: 35225888 PMCID: PMC8884015 DOI: 10.3390/neurolint14010018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 02/03/2022] [Accepted: 02/14/2022] [Indexed: 11/16/2022] Open
Abstract
POLR3B and POLR3A are the major subunits of RNA polymerase III, which synthesizes non-coding RNAs such as tRNAs and rRNAs. Nucleotide mutations of the RNA polymerase 3 subunit b (polr3b) gene are responsible for hypomyelinating leukodystrophy 8 (HLD8), which is an autosomal recessive oligodendroglial cell disease. Despite the important association between POLR3B mutation and HLD8, it remains unclear how mutated POLR3B proteins cause oligodendroglial cell abnormalities. Herein, we show that a severe HLD8-associated nonsense mutation (Arg550-to-Ter (R550X)) primarily localizes POLR3B proteins as protein aggregates into lysosomes in the FBD-102b cell line as an oligodendroglial precursor cell model. Conversely, wild type POLR3B proteins were not localized in lysosomes. Additionally, the expression of proteins with the R550X mutation in cells decreased lysosome-related signaling through the mechanistic target of rapamycin (mTOR). Cells harboring the mutant constructs did not exhibit oligodendroglial cell differentiated phenotypes, which have widespread membranes that extend from their cell body. However, cells harboring the wild type constructs exhibited differentiated phenotypes. Ibuprofen, which is a non-steroidal anti-inflammatory drug (NSAID), improved the defects in their differentiation phenotypes and signaling through mTOR. These results indicate that the HLD8-associated POLR3B proteins with the R550X mutation are localized in lysosomes, decrease mTOR signaling, and inhibit oligodendroglial cell morphological differentiation, and ibuprofen improves these cellular pathological effects. These findings may reveal some of the molecular and cellular pathological mechanisms underlying HLD8 and their amelioration.
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Affiliation(s)
- Sui Sawaguchi
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji 192-0392, Japan; (S.S.); (R.S.); (Y.M.)
| | - Rimi Suzuki
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji 192-0392, Japan; (S.S.); (R.S.); (Y.M.)
| | - Hiroaki Oizumi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan; (H.O.); (K.O.); (K.M.); (M.Y.)
| | - Katsuya Ohbuchi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan; (H.O.); (K.O.); (K.M.); (M.Y.)
| | - Kazushige Mizoguchi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan; (H.O.); (K.O.); (K.M.); (M.Y.)
| | - Masahiro Yamamoto
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan; (H.O.); (K.O.); (K.M.); (M.Y.)
| | - Yuki Miyamoto
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji 192-0392, Japan; (S.S.); (R.S.); (Y.M.)
- Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya 157-8535, Japan
| | - Junji Yamauchi
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji 192-0392, Japan; (S.S.); (R.S.); (Y.M.)
- Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya 157-8535, Japan
- Correspondence: ; Tel.: +81-42-676-7164; Fax: +81-42-676-8841
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48
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van der Knaap MS, Bonkowsky JL, Vanderver A, Schiffmann R, Krägeloh-Mann I, Bertini E, Bernard G, Fatemi SA, Wolf NI, Saunier-Vivar E, Rauner R, Dekker H, van Bokhoven P, van de Ven P, Leferink PS. Therapy Trial Design in Vanishing White Matter: An Expert Consortium Opinion. Neurol Genet 2022; 8:e657. [PMID: 35128050 PMCID: PMC8811717 DOI: 10.1212/nxg.0000000000000657] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 12/21/2021] [Indexed: 01/04/2023]
Abstract
Vanishing white matter (VWM) is a leukodystrophy caused by recessive variants in the genes EIF2B1-EIF2B5. It is characterized by chronic neurologic deterioration with superimposed stress-provoked episodes of rapid decline. Disease onset spans from the antenatal period through senescence. Age at onset predicts disease evolution for patients with early onset, whereas disease evolution is unpredictable for later onset; patients with infantile and early childhood onset consistently have severe disease with rapid neurologic decline and often early death, whereas patients with later onset have highly variable disease. VWM is rare, but likely underdiagnosed, particularly in adults. Apart from measures to prevent stressors that could provoke acute deteriorations, only symptomatic care is currently offered. With increased insight into VWM disease mechanisms, opportunities for treatment have emerged. EIF2B1-EIF2B5 encode the 5-subunit eukaryotic initiation factor 2B complex, which is essential for translation of mRNAs into proteins and is a principal regulator of the integrated stress response (ISR). ISR deregulation is central to VWM pathology. Targeting components of the ISR has proven beneficial in mutant VWM mouse models, and several drugs are now in clinical development. However, clinical trials in VWM pose considerable challenges: low numbers of known patients with VWM, unpredictable disease course for patients with onset after early childhood, absence of intermediate biomarkers, and novel first-in-human molecular targets. Given these challenges and considering the critical need to offer therapies, we have formulated recommendations for enhanced diagnosis, drug trial setup, and patient selection, based on our expert evaluation of molecular, laboratory, and clinical data.
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Affiliation(s)
- Marjo S van der Knaap
- Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Joshua L Bonkowsky
- Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Adeline Vanderver
- Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Raphael Schiffmann
- Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Ingeborg Krägeloh-Mann
- Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Enrico Bertini
- Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Genevieve Bernard
- Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Seyed Ali Fatemi
- Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Nicole I Wolf
- Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Elise Saunier-Vivar
- Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Robert Rauner
- Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Hanka Dekker
- Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Pieter van Bokhoven
- Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Peter van de Ven
- Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
| | - Prisca S Leferink
- Department of Pediatric Neurology (M.S.v.d.K., N.I.W.), Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers; Amsterdam Neuroscience (M.S.v.d.K., N.I.W.); Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, the Netherlands; Division of Pediatric Neurology (J.L.B.), Department of Pediatrics, University of Utah School of Medicine; Primary Children's Hospital (J.L.B.), Intermountain Healthcare, Salt Lake City, UT; Division of Neurology (A.V.), Children's Hospital of Philadelphia; Department of Neurology (A.V.), Perelman School of Medicine, University of Pennsylvania, PA; 4D Molecular Therapeutics (R.S.), Emeryville, CA; Department of Developmental and Child Neurology (I.K.-M.), Social Pediatrics, University Children's Hospital Tübingen, Germany; Department of Neuroscience (E.B.), Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, Rome 00146, Italy; Departments of Neurology and Neurosurgery (G.B.), Pediatrics and Human Genetics, McGill University; Department Specialized Medicine (G.B.), Division of Medical Genetics, McGill University Health Center; Child Health and Human Development Program (G.B.), Research Institute of the McGill University Health Center, Montreal, Canada; Kennedy Krieger Institute (S.A.F.), Johns Hopkins University, Baltimore, MD; Research Department (E.S.-V.), European Leukodystrophies Association International and European Leukodystrophies Association France, Paris, France; United Leukodystrophy Foundation (R.R.), DeKalb, IL; Vereniging Volwassenen, Kinderen en Stofwisselingsziekten (H.D.), Zwolle, the Netherlands; Industry Alliance Office (P.v.B., P.S.L.), Amsterdam Neuroscience, Amsterdam University Medical Centers; and Department of Epidemiology and Data Science (P.v.d.V.), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands
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49
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Naseer MI, Abdulkareem AA, Pushparaj PN, Saharti S, Muthaffar OY. Next-Generation Sequencing Reveals Novel Homozygous Missense Variant c.934T > C in POLR1C Gene Causing Leukodystrophy and Hypomyelinating Disease. Front Pediatr 2022; 10:862722. [PMID: 35685919 PMCID: PMC9171136 DOI: 10.3389/fped.2022.862722] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 03/07/2022] [Indexed: 11/13/2022] Open
Abstract
Leukodystrophies are a diverse group of genetically established disorders categorized by unusual white matter changes on brain imaging. Hypomyelinating leukodystrophies (HLDs) are a group of neurodevelopmental disorders that affect myelin sheath development in the brain. These disorders are categorized as developmental delay, spasticity, hypotonia, and intellectual disabilities. We describe a patient with developmental delay, cerebellar ataxia, spasticity, hypotonia, and intellectual disability from a healthy family member. Whole exome sequencing (WES) was performed to identify causative variants, which were further analyzed by bioinformatic analysis. WES was performed, and Sanger sequencing-based segregation analysis confirmed the presence of the homozygous missense variants of NM_203290.3 c.934T > C p.Ser312Pro of RNA polymerase I and III subunit C (POLR1C) gene in this patient and heterozygous variant in the unaffected carrier father and mother, supporting the pathogenicity and inheritance pattern of this variant. Furthermore, the variant identified by WES was validated in healthy controls (n = 100) using Sanger sequencing analysis. Finally, our study explained the important use of WES in disease diagnosis and provided further evidence that the variant in the POLR1C gene may play an important role in the development of hypomyelinating leukodystrophy in Saudi families.
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Affiliation(s)
- Muhammad Imran Naseer
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Angham Abdulrahman Abdulkareem
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Peter Natesan Pushparaj
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Pharmacology, Center for Transdisciplinary Research, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Chennai, India
| | - Samah Saharti
- Department of Pathology and Microbiology, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Osama Y Muthaffar
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
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50
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Sawaguchi S, Tago K, Oizumi H, Ohbuchi K, Yamamoto M, Mizoguchi K, Miyamoto Y, Yamauchi J. Hypomyelinating Leukodystrophy 7 (HLD7)-Associated Mutation of POLR3A Is Related to Defective Oligodendroglial Cell Differentiation, Which Is Ameliorated by Ibuprofen. Neurol Int 2021; 14:11-33. [PMID: 35076634 PMCID: PMC8788570 DOI: 10.3390/neurolint14010002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 12/14/2021] [Accepted: 12/21/2021] [Indexed: 01/13/2023] Open
Abstract
Hypomyelinating leukodystrophy 7 (HLD7) is an autosomal recessive oligodendroglial cell-related myelin disease, which is associated with some nucleotide mutations of the RNA polymerase 3 subunit a (polr3a) gene. POLR3A is composed of the catalytic core of RNA polymerase III synthesizing non-coding RNAs, such as rRNA and tRNA. Here, we show that an HLD7-associated nonsense mutation of Arg140-to-Ter (R140X) primarily localizes POLR3A proteins as protein aggregates into lysosomes in mouse oligodendroglial FBD-102b cells, whereas the wild type proteins are not localized in lysosomes. Expression of the R140X mutant proteins, but not the wild type proteins, in cells decreased signaling through the mechanistic target of rapamycin (mTOR), controlling signal transduction around lysosomes. While cells harboring the wild type constructs exhibited phenotypes with widespread membranes with myelin marker protein expression following the induction of differentiation, cells harboring the R140X mutant constructs did not exhibit them. Ibuprofen, a non-steroidal anti-inflammatory drug (NSAID), which is also known as an mTOR signaling activator, ameliorated defects in differentiation with myelin marker protein expression and the related signaling in cells harboring the R140X mutant constructs. Collectively, HLD7-associated POLR3A mutant proteins are localized in lysosomes where they decrease mTOR signaling, inhibiting cell morphological differentiation. Importantly, ibuprofen reverses undifferentiated phenotypes. These findings may reveal some of the pathological mechanisms underlying HLD7 and their amelioration at the molecular and cellular levels.
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Affiliation(s)
- Sui Sawaguchi
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan; (S.S.); (Y.M.)
| | - Kenji Tago
- Department of Biochemistry, Jichi Medical University, Shimotsuke 321-0498, Japan;
| | - Hiroaki Oizumi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan; (H.O.); (K.O.); (M.Y.); (K.M.)
| | - Katsuya Ohbuchi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan; (H.O.); (K.O.); (M.Y.); (K.M.)
| | - Masahiro Yamamoto
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan; (H.O.); (K.O.); (M.Y.); (K.M.)
| | - Kazushige Mizoguchi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan; (H.O.); (K.O.); (M.Y.); (K.M.)
| | - Yuki Miyamoto
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan; (S.S.); (Y.M.)
- Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535, Japan
| | - Junji Yamauchi
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan; (S.S.); (Y.M.)
- Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535, Japan
- Correspondence: ; Tel.: +81-42-676-7164; Fax: +81-42-676-8841
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