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Chaudhary R, Rehman M, Agarwal V, Kumar A, Kaushik AS, Srivastava S, Srivastava S, Verma R, Rajinikanth PS, Mishra V. Terra incognita of glial cell dynamics in the etiology of leukodystrophies: Broadening disease and therapeutic perspectives. Life Sci 2024; 354:122953. [PMID: 39122110 DOI: 10.1016/j.lfs.2024.122953] [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: 02/05/2024] [Revised: 07/09/2024] [Accepted: 08/05/2024] [Indexed: 08/12/2024]
Abstract
Neuroglial cells, also known as glia, are primarily characterized as auxiliary cells within the central nervous system (CNS). The recent findings have shed light on their significance in numerous physiological processes and their involvement in various neurological disorders. Leukodystrophies encompass an array of rare and hereditary neurodegenerative conditions that were initially characterized by the deficiency, aberration, or degradation of myelin sheath within CNS. The primary cellular populations that experience significant alterations are astrocytes, oligodendrocytes and microglia. These glial cells are either structurally or metabolically impaired due to inherent cellular dysfunction. Alternatively, they may fall victim to the accumulation of harmful by-products resulting from metabolic disturbances. In either situation, the possible replacement of glial cells through the utilization of implanted tissue or stem cell-derived human neural or glial progenitor cells hold great promise as a therapeutic strategy for both the restoration of structural integrity through remyelination and the amelioration of metabolic deficiencies. Various emerging treatment strategies like stem cell therapy, ex-vivo gene therapy, infusion of adeno-associated virus vectors, emerging RNA-based therapies as well as long-term therapies have demonstrated success in pre-clinical studies and show promise for rapid clinical translation. Here, we addressed various leukodystrophies in a comprehensive and detailed manner as well as provide prospective therapeutic interventions that are being considered for clinical trials. Further, we aim to emphasize the crucial role of different glial cells in the pathogenesis of leukodystrophies. By doing so, we hope to advance our understanding of the disease, elucidate underlying mechanisms, and facilitate the development of potential treatment interventions.
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Affiliation(s)
- Rishabh Chaudhary
- Department of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Raebareli Road, Lucknow 226025, U.P., India
| | - Mujeeba Rehman
- Department of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Raebareli Road, Lucknow 226025, U.P., India
| | - Vipul Agarwal
- Department of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Raebareli Road, Lucknow 226025, U.P., India
| | - Anand Kumar
- Department of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Raebareli Road, Lucknow 226025, U.P., India
| | - Arjun Singh Kaushik
- Department of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Raebareli Road, Lucknow 226025, U.P., India
| | - Siddhi Srivastava
- Department of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Raebareli Road, Lucknow 226025, U.P., India
| | - Sukriti Srivastava
- Department of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Raebareli Road, Lucknow 226025, U.P., India
| | - Rajkumar Verma
- University of Connecticut School of Medicine, 200 Academic Way, Farmington, CT 06032, USA
| | - P S Rajinikanth
- Department of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Raebareli Road, Lucknow 226025, U.P., India
| | - Vikas Mishra
- Department of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Raebareli Road, Lucknow 226025, U.P., India.
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Rogac M, Kovanda A, Lovrečić L, Peterlin B. Optical genome mapping in an atypical Pelizaeus-Merzbacher prenatal challenge. Front Genet 2023; 14:1173426. [PMID: 37560384 PMCID: PMC10407396 DOI: 10.3389/fgene.2023.1173426] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 07/14/2023] [Indexed: 08/11/2023] Open
Abstract
Pathogenic genetic variants represent a challenge in prenatal counseling, especially when clinical presentation in familial carriers is atypical. We describe a prenatal case involving a microarray-detected duplication of PLP1 which causes X-linked Pelizaeus-Merzbacher disease, a progressive hypomyelinating leukodystrophy. Because of atypical clinical presentation in an older male child, the duplication was examined using a novel technology, optical genome mapping, and was found to be an inverted duplication, which has not been previously described. Simultaneously, segregation analysis identified another healthy adult male carrier of this unique structural rearrangement. The novel PLP1 structural variant was reclassified, and a healthy boy was delivered. In conclusion, we suggest that examining structural variants with novel methods is warranted especially in cases with atypical clinical presentation and may in these cases lead to improved prenatal and postnatal genetic counseling.
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Affiliation(s)
- Mihael Rogac
- Clinical Institute of Genomic Medicine, University Medical Center Ljubljana, Ljubljana, Slovenia
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Anja Kovanda
- Clinical Institute of Genomic Medicine, University Medical Center Ljubljana, Ljubljana, Slovenia
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Luca Lovrečić
- Clinical Institute of Genomic Medicine, University Medical Center Ljubljana, Ljubljana, Slovenia
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Borut Peterlin
- Clinical Institute of Genomic Medicine, University Medical Center Ljubljana, Ljubljana, Slovenia
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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3
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Lebrigand K, Bergenstråhle J, Thrane K, Mollbrink A, Meletis K, Barbry P, Waldmann R, Lundeberg J. The spatial landscape of gene expression isoforms in tissue sections. Nucleic Acids Res 2023; 51:e47. [PMID: 36928528 PMCID: PMC10164556 DOI: 10.1093/nar/gkad169] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 02/06/2023] [Accepted: 02/23/2023] [Indexed: 03/18/2023] Open
Abstract
In situ capturing technologies add tissue context to gene expression data, with the potential of providing a greater understanding of complex biological systems. However, splicing variants and full-length sequence heterogeneity cannot be characterized at spatial resolution with current transcriptome profiling methods. To that end, we introduce spatial isoform transcriptomics (SiT), an explorative method for characterizing spatial isoform variation and sequence heterogeneity using long-read sequencing. We show in mouse brain how SiT can be used to profile isoform expression and sequence heterogeneity in different areas of the tissue. SiT reveals regional isoform switching of Plp1 gene between different layers of the olfactory bulb, and the use of external single-cell data allows the nomination of cell types expressing each isoform. Furthermore, SiT identifies differential isoform usage for several major genes implicated in brain function (Snap25, Bin1, Gnas) that are independently validated by in situ sequencing. SiT also provides for the first time an in-depth A-to-I RNA editing map of the adult mouse brain. Data exploration can be performed through an online resource (https://www.isomics.eu), where isoform expression and RNA editing can be visualized in a spatial context.
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Affiliation(s)
- Kevin Lebrigand
- Université Côte d’Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, F06560 Sophia Antipolis, France
| | - Joseph Bergenstråhle
- Department of Gene Technology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Science for Life Laboratory, Solna, Sweden
| | - Kim Thrane
- Department of Gene Technology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Science for Life Laboratory, Solna, Sweden
| | - Annelie Mollbrink
- Department of Gene Technology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Science for Life Laboratory, Solna, Sweden
| | | | - Pascal Barbry
- Université Côte d’Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, F06560 Sophia Antipolis, France
| | - Rainer Waldmann
- Université Côte d’Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, F06560 Sophia Antipolis, France
| | - Joakim Lundeberg
- Department of Gene Technology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Science for Life Laboratory, Solna, Sweden
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Duan R, Li L, Yan H, He M, Gao K, Xing S, Ji H, Wang J, Cao B, Li D, Xie H, Zhao S, Wu Y, Jiang Y, Xiao J, Gu Q, Li M, Zheng X, Chen L, Wang J. Novel Insight into the Potential Pathogenicity of Mitochondrial Dysfunction Resulting from PLP1 Duplication Mutations in Patients with Pelizaeus-Merzbacher Disease. Neuroscience 2021; 476:60-71. [PMID: 34506833 DOI: 10.1016/j.neuroscience.2021.08.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 11/17/2022]
Abstract
Among the hypomyelinating leukodystrophies, Pelizaeus-Merzbacher disease (PMD) is a representative disorder. The disease is caused by different types of PLP1 mutations, among which PLP1 duplication accounts for ∼70% of the mutations. Previous studies have shown that PLP1 duplications lead to PLP1 retention in the endoplasmic reticulum (ER); in parallel, recent studies have demonstrated that PLP1 duplication can also lead to mitochondrial dysfunction. As such, the respective roles and interactions of the ER and mitochondria in the pathogenesis of PLP1 duplication are not clear. In both PLP1 patients' and healthy fibroblasts, we measured mitochondrial respiration with a Seahorse XF Extracellular Analyzer and examined the interactions between the ER and mitochondria with super-resolution microscopy (spinning-disc pinhole-based structured illumination microscopy, SD-SIM). For the first time, we demonstrated that PLP1 duplication mutants had closer ER-mitochondrion interfaces mediated through structural and morphological changes in both the ER and mitochondria-associated membranes (MAMs). These changes in both the ER and mitochondria then led to mitochondrial dysfunction, as reported previously. This work highlights the roles of MAMs in bridging PLP1 expression in the ER and pathogenic dysfunction in mitochondria, providing novel insight into the pathogenicity of mitochondrial dysfunction resulting from PLP1 duplication. These findings suggest that interactions between the ER and mitochondria may underlie pathogenic mechanisms of hypomyelinating leukodystrophies diseases at the organelle level.
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Affiliation(s)
- Ruoyu Duan
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Liuju Li
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Peking University, Beijing 100871, China
| | - Huifang Yan
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Miao He
- Institute for Brain Research and Rehabilitation (IBRR), Guangdong Key Laboratory of Mental Health and Cognitive Science, South China Normal University, Guangzhou, China
| | - Kai Gao
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Shijia Xing
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Peking University, Beijing 100871, China
| | - Haoran Ji
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Jianyong Wang
- School of Software and Microelectronics, Peking University, Beijing 100871, China
| | - Binbin Cao
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Dongxiao Li
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Han Xie
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Shiqun Zhao
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Peking University, Beijing 100871, China
| | - Ye Wu
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Yuwu Jiang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Jiangxi Xiao
- Department of Radiology, Peking University First Hospital, Beijing, China
| | - Qiang Gu
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Ming Li
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Xiaolu Zheng
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Peking University, Beijing 100871, China; Institute of Biomedical Engineering, Beijing Institute of Collaborative Innovation (BICI), Beijing 100094, China.
| | - Liangyi Chen
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Peking University, Beijing 100871, China; National Biomedical Imaging Center, Peking University, Beijing 100871, China; PKU-IDG/McGovern Institute for Brain Research, Beijing 100871, China.
| | - Jingmin Wang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China; Key Laboratory for Neuroscience, Ministry of Education/National Health and Family Planning Commission, Peking University, Beijing 100034, China; Beijing Key Laboratory of Molecular Diagnosis and Study on Pediatric Genetic Diseases, Peking University First Hospital, Beijing 100083, China.
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Hortells L, Meyer EC, Thomas ZM, Yutzey KE. Periostin-expressing Schwann cells and endoneurial cardiac fibroblasts contribute to sympathetic nerve fasciculation after birth. J Mol Cell Cardiol 2021; 154:124-136. [PMID: 33582160 DOI: 10.1016/j.yjmcc.2021.02.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/12/2021] [Accepted: 02/04/2021] [Indexed: 10/22/2022]
Abstract
BACKGROUND The intracardiac nervous system (ICNS) is composed of neurons, in association with Schwann cells (SC) and endoneurial cardiac fibroblasts (ECF). Besides heart rhythm control, recent studies have implicated cardiac nerves in postnatal cardiac regeneration and cardiomyocyte size regulation, but cardiac SC and ECF remain understudied. During the postnatal period, the ICNS undergoes intense remodeling with nerve fasciculation and elongation throughout the myocardium, partially guided by the extracellular matrix (ECM). Here we report the origins, heterogeneity, and functions of SC and ECF that develop in proximity to neurons during postnatal ICNS maturation. METHODS AND RESULTS Periostin lineage (Postn+) cells include cardiac Remak SC and ECF during the postnatal period in mice. The developmental origins of cardiac SC and ECF were examined using Rosa26eGFP reporter mice bred with Wnt1Cre, expressed in Neural crest (NC)-derived lineages, or tamoxifen-inducible Tcf21MerCreMer, expressed predominantly in epicardial-derived fibroblast lineages. ICNS components are NC-derived with the exceptions of the myelinating Plp1+ SC and the Tcf21+ lineage-derived intramural ventricular ECF. In addition, Postn+ lineage GFAP- Remak SC and ECF are present around the fasciculating cardiac nerves. Whole mount studies of the NC-derived cells confirmed postnatal maturation of the complex ICNS network from P0 to P30. Sympathetic, parasympathetic, and sensory neurons fasciculate from P0 to P7 indicated by co-staining with PSA-NCAM. Ablation of Postn+ cells from P0 to P6 or loss of Periostin leads to reduced fasciculation of cardiac sympathetic nerves. In addition, collagen remodeling surrounding maturing nerves of the postnatal heart is reduced in Postn-null mice. CONCLUSIONS Postn+ cells include cardiac SC and ECF during postnatal nerve maturation, and these cells have different embryonic origins. At P7, the Postn+ cells associated with cardiac nerves are mainly Remak SC and ECF. Ablation of the Postn+ cells from P0 to P6 and also loss of Postn in Postn-null mice leads to reduced fasciculation of cardiac nerves at P7.
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Affiliation(s)
- Luis Hortells
- The Heart Institute, Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Evan C Meyer
- The Confocal Imaging Core, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Zachary M Thomas
- The Heart Institute, Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Katherine E Yutzey
- The Heart Institute, Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
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Xue H, Yu A, Chen X, Lin N, Lin M, Huang H, Xu L. Prenatal diagnosis of PLP1 duplication by single nucleotide polymorphism array in a family with Pelizaeus-Merzbacher disease. Aging (Albany NY) 2021; 13:1488-1497. [PMID: 33429367 PMCID: PMC7835049 DOI: 10.18632/aging.202477] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 11/10/2020] [Indexed: 11/25/2022]
Abstract
A family with a history of Pelizaeus-Merzbacher disease (PMD) received prenatal diagnosis of PLP1 gene duplication in a fetus using a single nucleotide polymorphism (SNP) array. A 27-year-old pregnant woman was referred for genetic counseling due to her four-year-old son being diagnosed with a suspected classic type of PMD. Amniocentesis was performed at 18 and 3/7 weeks of gestation, and the SNP array was carried out on DNA from the mother, her affected son, and fetus, then further confirmed by multiplex ligation-dependent probe amplification (MLPA). Cytogenetic analysis of the fetus showed 46,XY. SNP array analysis revealed that the male fetus did not carry PLP1 gene duplication but the affected boy did, and the mother was a carrier for the duplication of the PLP1 gene. All SNP array results were further confirmed by MLPA. SNP array and MLPA analyses of peripheral blood verified the nonduplication of the PLP1 gene in the infant after birth. At present, the child (without PLP1 duplication) is developing normally. This study preliminarily suggests that SNP array is a sensitive and accurate technology for identifying PLP1 duplication and is feasible for reliable diagnosis, including for the prenatal diagnosis of PMD resulting from PLP1 duplication.
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Affiliation(s)
- Huili Xue
- Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fujian Maternity and Child Health Hospital, Affiliated Hospital of Fujian Medical University, Gulou, Fuzhou 350001, Fujian Province, China
| | - Aili Yu
- Reproductive Medicine Center, Fujian Maternity and Child Health Hospital, Affiliated Hospital of Fujian Medical University, Gulou, Fuzhou 350001, Fujian Province, China
| | - Xuemei Chen
- Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fujian Maternity and Child Health Hospital, Affiliated Hospital of Fujian Medical University, Gulou, Fuzhou 350001, Fujian Province, China
| | - Na Lin
- Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fujian Maternity and Child Health Hospital, Affiliated Hospital of Fujian Medical University, Gulou, Fuzhou 350001, Fujian Province, China
| | - Min Lin
- Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fujian Maternity and Child Health Hospital, Affiliated Hospital of Fujian Medical University, Gulou, Fuzhou 350001, Fujian Province, China
| | - Hailong Huang
- Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fujian Maternity and Child Health Hospital, Affiliated Hospital of Fujian Medical University, Gulou, Fuzhou 350001, Fujian Province, China
| | - Liangpu Xu
- Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fujian Maternity and Child Health Hospital, Affiliated Hospital of Fujian Medical University, Gulou, Fuzhou 350001, Fujian Province, China
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The wmN1 Enhancer Region of the Mouse Myelin Proteolipid Protein Gene (mPlp1) is Indispensable for Expression of an mPlp1-lacZ Transgene in Both the CNS and PNS. Neurochem Res 2019; 45:663-671. [PMID: 31782102 DOI: 10.1007/s11064-019-02919-w] [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: 08/09/2019] [Revised: 11/19/2019] [Accepted: 11/22/2019] [Indexed: 10/25/2022]
Abstract
The myelin proteolipid protein gene (PLP1) encodes the most abundant protein in CNS myelin. Expression of the gene must be strictly regulated, as evidenced by human X-linked leukodystrophies resulting from variations in PLP1 copy number, including elevated dosages as well as deletions. Recently, we showed that the wmN1 region in human PLP1 (hPLP1) intron 1 is required to promote high levels of an hPLP1-lacZ transgene in mice, using a Cre-lox approach. The current study tests whether loss of the wmN1 region from a related transgene containing mouse Plp1 (mPlp1) DNA produces similar results. In addition, we investigated the effects of loss of another region (ASE) in mPlp1 intron 1. Previous studies have shown that the ASE is required to promote high levels of mPlp1-lacZ expression by transfection analysis, but had no effect when removed from the native gene in mouse. Whether this is due to compensation by another regulatory element in mPlp1 that was not included in the mPlp1-lacZ constructs, or to differences in methodology, is unclear. Two transgenic mouse lines were generated that harbor mPLP(+)Z/FL. The parental transgene utilizes mPlp1 sequences (proximal 2.3 kb of 5'-flanking DNA to the first 37 bp of exon 2) to drive expression of a lacZ reporter cassette. Here we demonstrate that mPLP(+)Z/FL is expressed in oligodendrocytes, oligodendrocyte precursor cells, olfactory ensheathing cells and neurons in brain, and Schwann cells in sciatic nerve. Loss of the wmN1 region from the parental transgene abolished expression, whereas removal of the ASE had no effect.
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Abstract
Pelizaeus-Merzbacher disease (PMD) is an X-linked disorder caused by mutations in the PLP1 gene, which encodes the proteolipid protein of myelinating oligodendroglia. PMD exhibits phenotypic variability that reflects its considerable genotypic heterogeneity, but all forms of the disease result in central hypomyelination associated with early neurologic dysfunction, progressive deterioration, and ultimately death. PMD has been classified into three major subtypes, according to the age of presentation: connatal PMD, classic PMD, and transitional PMD, combining features of both connatal and classic forms. Two other less severe phenotypes were subsequently described, including the spastic paraplegia syndrome and PLP1-null disease. These disorders may be associated with duplications, as well as with point, missense, and null mutations within the PLP1 gene. A number of clinically similar Pelizaeus-Merzbacher-like disorders (PMLD) are considered in the differential diagnosis of PMD, the most prominent of which is PMLD-1, caused by misexpression of the GJC2 gene encoding connexin-47. No effective therapy for PMD exists. Yet, as a relatively pure central nervous system hypomyelinating disorder, with limited involvement of the peripheral nervous system and little attendant neuronal pathology, PMD is an attractive therapeutic target for neural stem cell and glial progenitor cell transplantation, efforts at which are now underway in a number of centers internationally.
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Affiliation(s)
- M Joana Osório
- Center for Translational Neuromedicine and Department of Neurology, University of Rochester Medical Center, Rochester, NY, United States; Center for Translational Neuromedicine, University of Copenhagen Faculty of Health and Medical Sciences, Copenhagen, Denmark
| | - Steven A Goldman
- Center for Translational Neuromedicine and Department of Neurology, University of Rochester Medical Center, Rochester, NY, United States; Center for Translational Neuromedicine, University of Copenhagen Faculty of Health and Medical Sciences, Copenhagen, Denmark.
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Wight PA. Effects of Intron 1 Sequences on Human PLP1 Expression: Implications for PLP1-Related Disorders. ASN Neuro 2017; 9:1759091417720583. [PMID: 28735559 PMCID: PMC5528184 DOI: 10.1177/1759091417720583] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Alterations in the myelin proteolipid protein gene ( PLP1) may result in rare X-linked disorders in humans such as Pelizaeus-Merzbacher disease and spastic paraplegia type 2. PLP1 expression must be tightly regulated since null mutations, as well as elevated PLP1 copy number, both lead to disease. Previous studies with Plp1-lacZ transgenic mice have demonstrated that mouse Plp1 ( mPlp1) intron 1 DNA (which accounts for slightly more than half of the gene) is required for the mPlp1 promoter to drive significant levels of reporter gene expression in brain. However not much is known about the mechanisms that control expression of the human PLP1 gene ( hPLP1). Therefore this review will focus on sequences in hPLP1 intron 1 DNA deemed important for hPLP1 gene activity as well as a couple of "human-specific" supplementary exons within the first intron which are utilized to generate novel splice variants, and the potential role that these sequences may play in PLP1-linked disorders.
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Affiliation(s)
- Patricia A Wight
- 1 Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
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Mei Q, Sadovy Y, Dvornyk V. Molecular evolution of cryptochromes in fishes. Gene 2015; 574:112-20. [PMID: 26238701 DOI: 10.1016/j.gene.2015.07.086] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 07/03/2015] [Accepted: 07/30/2015] [Indexed: 11/18/2022]
Abstract
Circadian rhythmicity is an endogenous biological cycle of about 24h, which exists in cyanobacteria and fungi, plants and animals. Circadian rhythms improve the adaptability of organisms in both constant and changing environments. The cryptochrome (CRY) is a key element of the circadian system in various animal groups including fishes. We studied evolution of cryptochromes in the phylogenetically and ecologically diverse fish taxa. The phylogenetic tree of fish Cry features two major clades: Cry1 and Cry2. Teleosts possess extra copies of Cry1 due to the genome duplication, which resulted in 3 main paralogous subfamilies (1A, 1B and 1C). Cry1 experienced further diversification through additional duplications in some taxa. 1A of Cry1 is more conserved than the other paralogs (dN=0.010 ± 0.003, π=0.119 ± 0.058). The analysis of selection indicated that, while the Cry homologs in fish evolved under the different levels of selection pressure, strong purifying selection (average ω=0.017) dominated in their evolution.
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Affiliation(s)
- Qiming Mei
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, People's Republic of China
| | - Yvonne Sadovy
- School of Biological Sciences, University of Hong Kong, Pokfulam Rd., Hong Kong, SAR, People's Republic of China
| | - Volodymyr Dvornyk
- School of Biological Sciences, University of Hong Kong, Pokfulam Rd., Hong Kong, SAR, People's Republic of China; Department of Life Sciences, College of Science and General Studies, Alfaisal University, Riyadh, Saudi Arabia.
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11
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Visigalli D, Castagnola P, Capodivento G, Geroldi A, Bellone E, Mancardi G, Pareyson D, Schenone A, Nobbio L. Alternative Splicing in the HumanPMP22Gene: Implications in CMT1A Neuropathy. Hum Mutat 2015; 37:98-109. [DOI: 10.1002/humu.22921] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 10/11/2015] [Indexed: 11/08/2022]
Affiliation(s)
- Davide Visigalli
- Department of Neurosciences; Rehabilitation Ophthalmology; Genetics and Maternal-Infantile Sciences (DINOGMI) and CEBR; University of Genoa; Genoa Italy
| | | | - Giovanna Capodivento
- Department of Neurosciences; Rehabilitation Ophthalmology; Genetics and Maternal-Infantile Sciences (DINOGMI) and CEBR; University of Genoa; Genoa Italy
| | - Alessandro Geroldi
- Department of Neurosciences; Rehabilitation Ophthalmology; Genetics and Maternal-Infantile Sciences (DINOGMI) - Section of Medical Genetics; University of Genoa IRCCS AOU San Martino-IST; UOC Medical Genetics; Genoa Italy
| | - Emilia Bellone
- Department of Neurosciences; Rehabilitation Ophthalmology; Genetics and Maternal-Infantile Sciences (DINOGMI) - Section of Medical Genetics; University of Genoa IRCCS AOU San Martino-IST; UOC Medical Genetics; Genoa Italy
| | - Gianluigi Mancardi
- Department of Neurosciences; Rehabilitation Ophthalmology; Genetics and Maternal-Infantile Sciences (DINOGMI) and CEBR; University of Genoa; Genoa Italy
| | - Davide Pareyson
- Clinic of Central and Peripheral Degenerative Neuropathies Unit; IRCCS Foundation; C. Besta Neurological Institute; Milan Italy
| | - Angelo Schenone
- Department of Neurosciences; Rehabilitation Ophthalmology; Genetics and Maternal-Infantile Sciences (DINOGMI) and CEBR; University of Genoa; Genoa Italy
| | - Lucilla Nobbio
- Department of Neurosciences; Rehabilitation Ophthalmology; Genetics and Maternal-Infantile Sciences (DINOGMI) and CEBR; University of Genoa; Genoa Italy
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Masliah-Planchon J, Dupont C, Vartzelis G, Trimouille A, Eymard-Pierre E, Gay-Bellile M, Renaldo F, Dorboz I, Pagan C, Quentin S, Elmaleh M, Kotsogianni C, Konstantelou E, Drunat S, Tabet AC, Boespflug-Tanguy O. Insertion of an extra copy of Xq22.2 into 1p36 results in functional duplication of the PLP1 gene in a girl with classical Pelizaeus-Merzbacher disease. BMC MEDICAL GENETICS 2015; 16:77. [PMID: 26329556 PMCID: PMC4557901 DOI: 10.1186/s12881-015-0226-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 08/25/2015] [Indexed: 08/30/2023]
Abstract
Background Pelizaeus-Merzbacher disease (PMD) is an X-linked dysmyelinating disorder characterized by nystagmus, hypotonia, ataxia, progressive spasticity, and cognitive decline. PMD classically results from a duplication of a genomic segment encompassing the entire PLP1 gene. Since the PLP1 gene is located in Xq22, PMD affects mostly boys. Methods and results Here we report the case of a girl with typical PMD. Copy number analysis of the PLP1 locus revealed a duplication of the entire gene and FISH analysis showed that the extra copy of the PLP1 gene was actually inserted in chromosome 1p36. This insertion of an additional copy of PLP1 in an autosome led to a functional duplication irrespective of the X-inactivation pattern. Subsequent overexpression of PLP1 was the cause of the PMD phenotype observed in this girl. Further sequencing of the breakpoint junction revealed a microhomology and thus suggested a replication based mechanism (such as FoSTeS or MMBIR). Conclusion This case emphasizes the susceptibility of the PLP1 locus to complex rearrangement likely driven by the Xq22 local genomic architecture. In addition, careful consideration should be given to girls with classical PMD clinical features since they usually experience complex PLP1 genomic alteration with a distinct risk of inheritance.
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Affiliation(s)
- Julien Masliah-Planchon
- UF de Génétique moléculaire, Hôpital Robert Debré, AP-HP, Paris, France. .,Inserm U1141, Université Paris Diderot, Sorbonne Paris Cité, Hôpital Robert Debré, Paris, France. .,New adresse: Unité de Génétique Somatique, Institut Curie, Paris, France.
| | - Céline Dupont
- UF de Cytogénétique, Hôpital Robert Debré, AP-HP, Paris, France.
| | - George Vartzelis
- Paediatric Neurology, P&A Kyriakou Paed. Hospital, Athens Medical School, Athens, Greece.
| | - Aurélien Trimouille
- UF de Génétique moléculaire, Hôpital Robert Debré, AP-HP, Paris, France. .,Inserm U1141, Université Paris Diderot, Sorbonne Paris Cité, Hôpital Robert Debré, Paris, France.
| | - Eléonore Eymard-Pierre
- Cytogénétique Médicale, Univ Clermont1, UFR Médecine, CHU Estaing, Clermont-Ferrand, France. .,ERTICa, EA 4677, Univ Clermont1, UFR Médecine, Clermont-Ferrand, France.
| | - Mathilde Gay-Bellile
- Cytogénétique Médicale, Univ Clermont1, UFR Médecine, CHU Estaing, Clermont-Ferrand, France. .,ERTICa, EA 4677, Univ Clermont1, UFR Médecine, Clermont-Ferrand, France.
| | - Florence Renaldo
- Inserm U1141, Université Paris Diderot, Sorbonne Paris Cité, Hôpital Robert Debré, Paris, France. .,Neurologie et maladie métabolique, Hôpital Robert Debré, AP-HP, Paris, France.
| | - Imen Dorboz
- Inserm U1141, Université Paris Diderot, Sorbonne Paris Cité, Hôpital Robert Debré, Paris, France.
| | - Cécile Pagan
- UF de Génétique moléculaire, Hôpital Robert Debré, AP-HP, Paris, France.
| | | | - Monique Elmaleh
- Imagerie pédiatrique, Hôpital Robert Debré, AP-HP, Paris, France.
| | - Christina Kotsogianni
- Paediatric Neurology, P&A Kyriakou Paed. Hospital, Athens Medical School, Athens, Greece.
| | - Elissavet Konstantelou
- Paediatric Neurology, P&A Kyriakou Paed. Hospital, Athens Medical School, Athens, Greece.
| | - Séverine Drunat
- UF de Génétique moléculaire, Hôpital Robert Debré, AP-HP, Paris, France. .,Inserm U1141, Université Paris Diderot, Sorbonne Paris Cité, Hôpital Robert Debré, Paris, France.
| | | | - Odile Boespflug-Tanguy
- Inserm U1141, Université Paris Diderot, Sorbonne Paris Cité, Hôpital Robert Debré, Paris, France. .,Neurologie et maladie métabolique, Hôpital Robert Debré, AP-HP, Paris, France.
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Bartoletti-Stella A, Gasparini L, Giacomini C, Corrado P, Terlizzi R, Giorgio E, Magini P, Seri M, Baruzzi A, Parchi P, Brusco A, Cortelli P, Capellari S. Messenger RNA processing is altered in autosomal dominant leukodystrophy. Hum Mol Genet 2015; 24:2746-56. [PMID: 25637521 PMCID: PMC4406291 DOI: 10.1093/hmg/ddv034] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Accepted: 01/27/2015] [Indexed: 02/06/2023] Open
Abstract
Adult-onset autosomal dominant leukodystrophy (ADLD) is a slowly progressive neurological disorder characterized by autonomic dysfunction, followed by cerebellar and pyramidal features. ADLD is caused by duplication of the lamin B1 gene (LMNB1), which leads to its increased expression. The molecular pathways involved in the disease are still poorly understood. Hence, we analyzed global gene expression in fibroblasts and whole blood of LMNB1 duplication carriers and used Gene Set Enrichment Analysis to explore their gene signatures. We found that LMNB1 duplication is associated with dysregulation of genes involved in the immune system, neuronal and skeletal development. Genes with an altered transcriptional profile clustered in specific genomic regions. Among the dysregulated genes, we further studied the role of RAVER2, which we found to be overexpressed at mRNA and protein level. RAVER2 encodes a putative trans regulator of the splicing repressor polypyrimidine tract binding protein (PTB) and is likely implicated in alternative splicing regulation. Functional studies demonstrated an abnormal splicing pattern of several PTB-target genes and of the myelin protein gene PLP1, previously demonstrated to be involved in ADLD. Mutant mice with different lamin B1 expression levels confirmed that Raver2 expression is dependent on lamin B1 in neural tissue and determines an altered splicing pattern of PTB-target genes and Plp1. Overall our results demonstrate that deregulation of lamin B1 expression induces modified splicing of several genes, likely driven by raver-2 overexpression, and suggest that an alteration of mRNA processing could be a pathogenic mechanism in ADLD.
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Affiliation(s)
- Anna Bartoletti-Stella
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna 40123, Italy
| | - Laura Gasparini
- Department of Neuroscience and Brain Techonologies, Istituto Italiano di Tecnologia, Genova 16163, Italy
| | - Caterina Giacomini
- Department of Neuroscience and Brain Techonologies, Istituto Italiano di Tecnologia, Genova 16163, Italy
| | - Patrizia Corrado
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna 40123, Italy
| | - Rossana Terlizzi
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna 40123, Italy, IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Ospedale Bellaria, Bologna 40139, Italy
| | - Elisa Giorgio
- Department of Medical Sciences, University of Torino, Torino 10126, Italy
| | - Pamela Magini
- Medical Genetics Unit, Department of Medical and Surgical Sciences, University of Bologna 40138, Italy and
| | - Marco Seri
- Medical Genetics Unit, Department of Medical and Surgical Sciences, University of Bologna 40138, Italy and
| | - Agostino Baruzzi
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Ospedale Bellaria, Bologna 40139, Italy
| | - Piero Parchi
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna 40123, Italy, IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Ospedale Bellaria, Bologna 40139, Italy
| | - Alfredo Brusco
- Department of Medical Sciences, University of Torino, Torino 10126, Italy, Città della Salute e della Scienza, University Hospital, Medical Genetics Unit, Torino 10126, Italy
| | - Pietro Cortelli
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna 40123, Italy, IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Ospedale Bellaria, Bologna 40139, Italy
| | - Sabina Capellari
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna 40123, Italy, IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Ospedale Bellaria, Bologna 40139, Italy,
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Mandler MD, Ku L, Feng Y. A cytoplasmic quaking I isoform regulates the hnRNP F/H-dependent alternative splicing pathway in myelinating glia. Nucleic Acids Res 2014; 42:7319-29. [PMID: 24792162 PMCID: PMC4066780 DOI: 10.1093/nar/gku353] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The selective RNA-binding protein quaking I (QKI) plays important roles in controlling alternative splicing (AS). Three QKI isoforms are broadly expressed, which display distinct nuclear-cytoplasmic distribution. However, molecular mechanisms by which QKI isoforms control AS, especially in distinct cell types, still remain elusive. The quakingviable (qkv) mutant mice carry deficiencies of all QKI isoforms in oligodendrocytes (OLs) and Schwann cells (SWCs), the myelinating glia of central and peripheral nervous system (CNS and PNS), respectively, resulting in severe dysregulation of AS. We found that the cytoplasmic isoform QKI-6 regulates AS of polyguanine (G-run)-containing transcripts in OLs and rescues aberrant AS in the qkv mutant by repressing expression of two canonical splicing factors, heterologous nuclear ribonucleoproteins (hnRNPs) F and H. Moreover, we identified a broad spectrum of in vivo functional hnRNP F/H targets in OLs that contain conserved exons flanked by G-runs, many of which are dysregulated in the qkv mutant. Interestingly, AS targets of the QKI-6-hnRNP F/H pathway in OLs are differentially affected in SWCs, suggesting that additional cell-type-specific factors modulate AS during CNS and PNS myelination. Together, our studies provide the first evidence that cytoplasmic QKI-6 acts upstream of hnRNP F/H, which forms a novel pathway to control AS in myelinating glia.
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Affiliation(s)
- Mariana D Mandler
- Department of Pharmacology, Emory University, Atlanta, GA 30329, USA
| | - Li Ku
- Department of Pharmacology, Emory University, Atlanta, GA 30329, USA
| | - Yue Feng
- Department of Pharmacology, Emory University, Atlanta, GA 30329, USA
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15
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Patient-derived iPS cells for unveiling the molecular pathology of Pelizaeus-Merzbacher disease: a commentary on 'Reduced PLP1 expression in induced pluripotent stem cells derived from a Pelizaeus-Merzbacher disease patient with a partial PLP1 duplication'. J Hum Genet 2012; 57:553-4. [PMID: 22786577 DOI: 10.1038/jhg.2012.85] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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16
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Shimojima K, Inoue T, Imai Y, Arai Y, Komoike Y, Sugawara M, Fujita T, Ideguchi H, Yasumoto S, Kanno H, Hirose S, Yamamoto T. Reduced PLP1 expression in induced pluripotent stem cells derived from a Pelizaeus-Merzbacher disease patient with a partial PLP1 duplication. J Hum Genet 2012; 57:580-6. [PMID: 22695888 DOI: 10.1038/jhg.2012.71] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Pelizaeus-Merzbacher disease (PMD) is an X-linked recessive disorder characterized by dysmyelination of the central nervous system (CNS). We identified a rare partial duplication of the proteolipid protein 1 gene (PLP1) in a patient with PMD. To assess the underlying effect of this duplication, we examined PLP1 expression in induced pluripotent stem (iPS) cells generated from the patient's fibroblasts. Disease-specific iPS cells were generated from skin fibroblasts obtained from the indicated PMD patient and two other PMD patients having a 637-kb chromosomal duplication including entire PLP1 and a novel missense mutation (W212C) of PLP1, by transfections of OCT3/4, C-MYC, KLF4 and SOX2 using retro-virus vectors. PLP1 expressions in the generated iPS cells were examined by northern blot analysis. Although PLP1 expression was confirmed in iPS cells generated from two patients with the entire PLP1 duplication and the missense mutation of PLP1, iPS cells generated from the patient with the partial PLP1 duplication manifesting a milder form of PMD showed null expression. This indicated that the underlying effect of the partial PLP1 duplication identified in this study was different from other PLP1 alterations including a typical duplication and a missense mutation.
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Affiliation(s)
- Keiko Shimojima
- Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Kawaguchi, Japan
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Kitsiou-Tzeli S, Konstantinidou A, Sofocleous C, Kosma K, Syrmou A, Giannikou K, Sifakis S, Makrythanasis P, Tzetis M. Familial Pelizaeus-Merzbacher disease caused by a 320.6-kb Xq22.2 duplication and the pathological findings of a male fetus. ACTA ACUST UNITED AC 2012; 94:494-8. [PMID: 22511562 DOI: 10.1002/bdra.23015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 03/09/2012] [Accepted: 03/10/2012] [Indexed: 01/04/2023]
Abstract
BACKGROUND Pelizaeus-Merzbacher disease (PMD) is a recessive, X-linked leukoencephalopathy attributed to impaired myelination during central nervous system development, caused by defects in the proteolipid protein 1 (PLP1) gene. PMD presents clinical variability, ranging from the severe connatal form to the classic form. CASES We report the clinical and molecular findings of two affected males, three carrier females, and an aborted male fetus with familial PMD. The two male probands presented with severe PMD phenotype and intellectual disability. High-resolution oligonucleotide-based array comparative genomic hybridization (aCGH) identified an Xq22.2 duplication of 320.6 kb (102641391-102961998, hg18), including the PLP1 gene and surrounding chromosomal region. Postmortem examination of the aborted fetus at 25 weeks' gestation showed focal subcortical white matter degeneration, focal gliosis, and cerebellar atrophy. CONCLUSIONS Genotype-phenotype correlation is provided. In the connatal form of PMD, leukodystrophy and cerebellar atrophy can occur antenatally and be established at 25 weeks' gestation. The observation of degenerative brain lesions occurring before the onset of subcortical myelination suggests that the PLP1 gene has a more complex role in human brain development, exceeding its structural function in myelin formation.
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18
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Wood PL, Khan MA, Smith T, Ehrmantraut G, Jin W, Cui W, Braverman NE, Goodenowe DB. In vitro and in vivo plasmalogen replacement evaluations in rhizomelic chrondrodysplasia punctata and Pelizaeus-Merzbacher disease using PPI-1011, an ether lipid plasmalogen precursor. Lipids Health Dis 2011; 10:182. [PMID: 22008564 PMCID: PMC3238230 DOI: 10.1186/1476-511x-10-182] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Accepted: 10/18/2011] [Indexed: 01/21/2023] Open
Abstract
Background Childhood peroxisomal disorders and leukodystrophies are devastating diseases characterized by dysfunctional lipid metabolism. Plasmalogens (ether glycerophosphoethanolamine lipids) are decreased in these genetic disorders. The biosynthesis of plasmalogens is initiated in peroxisomes but completed in the endoplasmic reticulum. We therefore undertook a study to evaluate the ability of a 3-substituted, 1-alkyl, 2-acyl glyceryl ether lipid (PPI-1011) to replace plasmalogens in rhizomelic chrondrodysplasia punctata type 1 (RCDP1) and rhizomelic chrondrodysplasia punctata type 2 (RCDP2) lymphocytes which possess peroxisomal mutations culminating in deficient plasmalogen synthesis. We also examined plasmalogen synthesis in Pelizaeus-Merzbacher disease (PMD) lymphocytes which possess a proteolipid protein-1 (PLP1) missense mutation that results in abnormal PLP1 folding and it's accumulation in the endoplasmic reticulum (ER), the cellular site of the last steps in plasmalogen synthesis. In vivo incorporation of plasmalogen precursor into tissue plasmalogens was also evaluated in the Pex7 mouse model of plasmalogen deficiency. Results In both RCDP1 and RCDP2 lymphocytes, PPI-1011 repleted the target ethanolamine plasmalogen (PlsEtn16:0/22:6) in a concentration dependent manner. In addition, deacylation/reacylation reactions resulted in repletion of PlsEtn 16:0/20:4 in both RCDP1 and RCDP2 lymphocytes, repletion of PlsEtn 16:0/18:1 and PlsEtn 16:0/18:2 in RCDP2 lymphocytes, and partial repletion of PlsEtn 16:0/18:1 and PlsEtn 16:0/18:2 in RCDP1 lymphocytes. In the Pex7 mouse, oral dosing of labeled PPI-1011 demonstrated repletion of tissue levels of the target plasmalogen PlsEtn 16:0/22:6 with phospholipid remodeling also resulting in significant repletion of PlsEtn 16:0/20:4 and PlsEtn 16:0/18:1. Metabolic conversion of PPI-1011 to the target plasmalogen was most active in the liver. Conclusions Our data demonstrate that PPI-1011 is activated (removal of 3-substitution) and converted to PlsEtn in vitro in both RCDP1 and RCDP2 lymphocytes and in vivo in the Pex7 mouse model of RCPD1 effectively bypassing the peroxisomal dysfunction present in these disorders. While PPI-1011 was shown to replete PlsEtns 16:0/x, ether lipid precursors of PlsEtn 18:0/x and PlsEtn 18:1/x may also be needed to achieve optimal clinical benefits of plasmalogen replacement in these complex patient populations. In contrast, only limited plasmalogen replacement was observed in PMD lymphocytes suggesting that the effects of protein misfolding and accumulation in the ER negatively affect processing of plasmalogen precursors in this cellular compartment.
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Affiliation(s)
- Paul L Wood
- Dept, of Pharmacology, DeBusk College of Osteopathic Medicine, Lincoln Memorial University, 6965 Cumberland Gap Parkway, Harrogate, TN 37752, USA.
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Wood PL, Smith T, Pelzer L, Goodenowe DB. Targeted metabolomic analyses of cellular models of pelizaeus-merzbacher disease reveal plasmalogen and myo-inositol solute carrier dysfunction. Lipids Health Dis 2011; 10:102. [PMID: 21682894 PMCID: PMC3141545 DOI: 10.1186/1476-511x-10-102] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Accepted: 06/17/2011] [Indexed: 11/17/2022] Open
Abstract
Background Leukodystrophies are devastating diseases characterized by dys- and hypo-myelination. While there are a number of histological and imaging studies of these disorders, there are limited biochemical data available. We undertook targeted lipidomic analyses of Pelizaeus-Merzbacher disease (PMD) fibroblasts, PMD lymphocytes, and 158JP oligodendrocytes, a murine model of PMD, to define the lipid changes in these cell models. Further targeted metabolomics analyses were conducted to obtain a preliminary evaluation of the metabolic consequences of lipid changes and gene mutations in these cell models. Results In both PMD fibroblasts and lymphocytes, and 158JP oligodendrocytes, ethanolamine plasmalogens were significantly decreased. Labeling studies with 158JP oligodendrocytes further demonstrated a decreased rate of lipid remodeling at sn-2. Targeted metabolomics analyses of these cells revealed dramatic increases in cellular levels of myo-inositol. Further uptake studies demonstrated increased rates of myo-inositol uptake by PMD lymphocytes. Conclusions Our data demonstrating PlsEtn decrements, support previous studies indicating leukodystrophy cells possess significant peroxisomal deficits. Our data for the first time also demonstrate that decrements in peroxisomal function coupled with the PLP1 gene defects of PMD, result in changes in the function of membrane myo-inositol solute carriers resulting in dramatic increases in cellular myo-inositol levels.
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Affiliation(s)
- Paul L Wood
- Phenomenome Discoveries Inc, 204-407 Downey Road, Saskatoon, SK S7N4L8, Canada.
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20
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Grossi S, Regis S, Biancheri R, Mort M, Lualdi S, Bertini E, Uziel G, Boespflug-Tanguy O, Simonati A, Corsolini F, Demir E, Marchiani V, Percesepe A, Stanzial F, Rossi A, Vaurs-Barrière C, Cooper DN, Filocamo M. Molecular genetic analysis of the PLP1 gene in 38 families with PLP1-related disorders: identification and functional characterization of 11 novel PLP1 mutations. Orphanet J Rare Dis 2011; 6:40. [PMID: 21679407 PMCID: PMC3125326 DOI: 10.1186/1750-1172-6-40] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Accepted: 06/16/2011] [Indexed: 12/18/2022] Open
Abstract
Background The breadth of the clinical spectrum underlying Pelizaeus-Merzbacher disease and spastic paraplegia type 2 is due to the extensive allelic heterogeneity in the X-linked PLP1 gene encoding myelin proteolipid protein (PLP). PLP1 mutations range from gene duplications of variable size found in 60-70% of patients to intragenic lesions present in 15-20% of patients. Methods Forty-eight male patients from 38 unrelated families with a PLP1-related disorder were studied. All DNA samples were screened for PLP1 gene duplications using real-time PCR. PLP1 gene sequencing analysis was performed on patients negative for the duplication. The mutational status of all 14 potential carrier mothers of the familial PLP1 gene mutation was determined as well as 15/24 potential carrier mothers of the PLP1 duplication. Results and Conclusions PLP1 gene duplications were identified in 24 of the unrelated patients whereas a variety of intragenic PLP1 mutations were found in the remaining 14 patients. Of the 14 different intragenic lesions, 11 were novel; these included one nonsense and 7 missense mutations, a 657-bp deletion, a microdeletion and a microduplication. The functional significance of the novel PLP1 missense mutations, all occurring at evolutionarily conserved residues, was analysed by the MutPred tool whereas their potential effect on splicing was ascertained using the Skippy algorithm and a neural network. Although MutPred predicted that all 7 novel missense mutations would be likely to be deleterious, in silico analysis indicated that four of them (p.Leu146Val, p.Leu159Pro, p.Thr230Ile, p.Ala247Asp) might cause exon skipping by altering exonic splicing elements. These predictions were then investigated in vitro for both p.Leu146Val and p.Thr230Ile by means of RNA or minigene studies and were subsequently confirmed in the case of p.Leu146Val. Peripheral neuropathy was noted in four patients harbouring intragenic mutations that altered RNA processing, but was absent from all PLP1-duplication patients. Unprecedentedly, family studies revealed the de novo occurrence of the PLP1 duplication at a frequency of 20%.
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Affiliation(s)
- Serena Grossi
- SSD Lab, Diagnosi Pre-Postnatale Malattie Metaboliche, IRCCS G, Gaslini, Genova, Italy
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A three-step workflow procedure for the interpretation of array-based comparative genome hybridization results in patients with idiopathic mental retardation and congenital anomalies. Genet Med 2010; 12:478-85. [PMID: 20734469 DOI: 10.1097/gim.0b013e3181e3914a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
One of the aims of clinical genetics is to identify gene mutations or genomic rearrangements that may underlie complex presentations of phenotypic features, such as multiple congenital malformations and mental retardation. During the decade after publication of the first article on array-based comparative genome hybridization, this technique has supplemented karyotyping as the prime genome-wide screening method in patients with idiopathic multiple congenital malformations and mental retardation. The use of this novel, discovery-based, approach has dramatically increased the detection rate of genomic imbalances. Array-based comparative genome hybridization detects copy number changes in the genome of patients and healthy subjects, some of which may represent phenotypically neutral copy number variations. This prompts the need for properly distinguishing between those copy number changes that may contribute to the clinical phenotype amid a pool of neutral copy number variations. We briefly review the characteristics of copy number changes in relation to their clinical relevance. Second, we discuss several published workflow schemes to identify copy number changes putatively contributing to the phenotype, and third, we propose a three-step procedure aiming to rapidly evaluate copy number changes on a case-by-case basis as to their potential contribution to the phenotype of patients with idiopathic multiple congenital malformations and mental retardation. This workflow is gene-centered and should aid in identification of disease-related candidate genes and in estimating the recurrence risk for the disorder in the family.
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Mochel F, Boildieu N, Barritault J, Sarret C, Eymard-Pierre E, Seguin F, Schiffmann R, Boespflug-Tanguy O. Elevated CSF N-acetylaspartylglutamate suggests specific molecular diagnostic abnormalities in patients with white matter diseases. Biochim Biophys Acta Mol Basis Dis 2010; 1802:1112-7. [PMID: 20637281 DOI: 10.1016/j.bbadis.2010.07.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2010] [Revised: 07/04/2010] [Accepted: 07/07/2010] [Indexed: 11/16/2022]
Abstract
BACKGROUND In order to identify biomarkers useful for the diagnosis of genetic white matter disorders we compared the metabolic profile of patients with leukodystrophies with a hypomyelinating or a non-hypomyelinating MRI pattern. METHODS We used a non-a priori method of in vitro ¹H-NMR spectroscopy on CSF samples of 74 patients with leukodystrophies. RESULTS We found an elevation of CSF N-acetylaspartylglutamate (NAAG) in patients with Pelizaeus-Merzbacher disease (PMD)-PLP1 gene, Pelizaeus-Merzbacher-like disease-GJC2 gene and Canavan disease-ASPA gene. In the PMD group, NAAG was significantly elevated in the CSF of all patients with PLP1 duplication (19/19) but was strictly normal in 6 out of 7 patients with PLP1 point mutations. Additionally, we previously reported increased CSF NAAG in patients with SLC17A5 mutations. CONCLUSIONS Elevated CSF NAAG is a biomarker that suggests specific molecular diagnostic abnormalities in patients with white matter diseases. Our findings also point to unique pathological functions of the overexpressed PLP in PMD patients with duplication of this gene.
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Affiliation(s)
- Fanny Mochel
- APHP, Department of Genetics, Hôpital de La Salpêtrière, Paris, France.
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