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Christen M, Gregor KM, Böttcher-Künneke A, Lombardo MS, Baumgärtner W, Jagannathan V, Puff C, Leeb T. Intragenic MFSD8 duplication and histopathological findings in a rabbit with neuronal ceroid lipofuscinosis. Anim Genet 2024; 55:588-598. [PMID: 38712841 DOI: 10.1111/age.13441] [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: 03/20/2024] [Revised: 03/20/2024] [Accepted: 04/22/2024] [Indexed: 05/08/2024]
Abstract
Neuronal ceroid lipofuscinoses (NCL) are among the most prevalent neurodegenerative disorders of early life in humans. Disease-causing variants have been described for 13 different NCL genes. In this study, a refined pathological characterization of a female rabbit with progressive neurological signs reminiscent of NCL was performed. Cytoplasmic pigment present in neurons was weakly positive with Sudan black B and autofluorescent. Immunohistology revealed astrogliosis, microgliosis and axonal degeneration. During the subsequent genetic investigation, the genome of the affected rabbit was sequenced and examined for private variants in NCL candidate genes. The analysis revealed a homozygous ~10.7 kb genomic duplication on chromosome 15 comprising parts of the MFSD8 gene, NC_013683.1:g.103,727,963_103,738,667dup. The duplication harbors two internal protein coding exons and is predicted to introduce a premature stop codon into the transcript, truncating ~50% of the wild-type MFSD8 open reading frame encoding the major facilitator superfamily domain containing protein 8, XP_002717309.2:p.(Glu235Leufs*23). Biallelic loss-of-function variants in MFSD8 have been described to cause NCL7 in human patients, dogs and a single cat. The available clinical and pathological data, together with current knowledge about MFSD8 variants and their functional impact in other species, point to the MFSD8 duplication as a likely causative defect for the observed phenotype in the affected rabbit.
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Affiliation(s)
- Matthias Christen
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Katharina M Gregor
- Department of Pathology, University of Veterinary Medicine Hannover, Hannover, Germany
| | | | - Mara S Lombardo
- Department of Pathology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Wolfgang Baumgärtner
- Department of Pathology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Vidhya Jagannathan
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Christina Puff
- Department of Pathology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Tosso Leeb
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
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2
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Huber RJ, Gray J, Kim WD. Loss of mfsd8 alters the secretome during Dictyostelium aggregation. Eur J Cell Biol 2023; 102:151361. [PMID: 37742391 DOI: 10.1016/j.ejcb.2023.151361] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 09/15/2023] [Accepted: 09/16/2023] [Indexed: 09/26/2023] Open
Abstract
Major facilitator superfamily domain-containing protein 8 (MFSD8) is a transmembrane protein that has been reported to function as a lysosomal chloride channel. In humans, homozygous mutations in MFSD8 cause a late-infantile form of neuronal ceroid lipofuscinosis (NCL) called CLN7 disease. In the social amoeba Dictyostelium discoideum, Mfsd8 localizes to cytoplasmic puncta and vesicles, and regulates conserved processes during the organism's life cycle. Here, we used D. discoideum to examine the effect of mfsd8-deficiency on the secretome during the early stages of multicellular development. Mass spectrometry revealed 61 proteins that were differentially released by cells after 4 and 8 h of starvation. Most proteins were present in increased amounts in mfsd8- conditioned buffer compared to WT indicating that loss of mfsd8 deregulates protein secretion and/or causes the release of proteins not normally secreted by WT cells. GO term enrichment analyses showed that many of the proteins aberrantly released by mfsd8- cells localize to compartments and regions of the cell associated with the endo-lysosomal and secretory pathways. Mass spectrometry also revealed proteins previously known to be impacted by the loss of mfsd8 (e.g., cathepsin D), as well as proteins that may underlie mfsd8-deficiency phenotypes during aggregation. Finally, we show that mfsd8-deficiency reduces intracellular proteasome 20S activity due to the abnormal release of at least one proteasomal subunit. Together, this study reveals the impact of mfsd8 loss on the secretome during D. discoideum aggregation and lays the foundation for follow up work that investigates the role of altered protein release in CLN7 disease.
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Affiliation(s)
- Robert J Huber
- Department of Biology, Trent University, Peterborough, Ontario, Canada; Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Ontario, Canada.
| | - Joshua Gray
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Ontario, Canada
| | - William D Kim
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Ontario, Canada
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3
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Bernardi S, Gemignani F, Marchese M. The involvement of Purkinje cells in progressive myoclonic epilepsy: Focus on neuronal ceroid lipofuscinosis. Neurobiol Dis 2023; 185:106258. [PMID: 37573956 PMCID: PMC10480493 DOI: 10.1016/j.nbd.2023.106258] [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: 05/25/2023] [Revised: 08/01/2023] [Accepted: 08/11/2023] [Indexed: 08/15/2023] Open
Abstract
The progressive myoclonic epilepsies (PMEs) are a group of rare neurodegenerative diseases characterized by myoclonus, epileptic seizures, and progressive neurological deterioration with cerebellar involvement. They include storage diseases like Gaucher disease, Lafora disease, and forms of neuronal ceroid lipofuscinosis (NCL). To date, 13 NCLs have been reported (CLN1-CLN8, CLN10-CLN14), associated with mutations in different genes. These forms, which affect both children and adults, are characterized by seizures, cognitive and motor impairments, and in most cases visual loss. In NCLs, as in other PMEs, central nervous system (CNS) neurodegeneration is widespread and involves different subpopulations of neurons. One of the most affected regions is the cerebellar cortex, where motor and non-motor information is processed and transmitted to deep cerebellar nuclei through the axons of Purkinje cells (PCs). PCs, being GABAergic, have an inhibitory effect on their target neurons, and provide the only inhibitory output of the cerebellum. Degeneration of PCs has been linked to motor impairments and epileptic seizures. Seizures occur when some insult upsets the normal balance in the CNS between excitatory and inhibitory impulses, causing hyperexcitability. Here we review the role of PCs in epilepsy onset and progression following their PME-related loss. In particular, we focus on the involvement of PCs in seizure phenotype in NCLs, highlighting findings from case reports and studies of animal models in which epilepsy can be linked to PC loss.
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Affiliation(s)
- Sara Bernardi
- Department Neurobiology and Molecular Medicine, IRCCS Fondazione Stella Maris, 56128 Pisa, Italy; Department of Biology, University of Pisa, Pisa, Italy
| | | | - Maria Marchese
- Department Neurobiology and Molecular Medicine, IRCCS Fondazione Stella Maris, 56128 Pisa, Italy.
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4
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Linear Diagnostic Procedure Elicited by Clinical Genetics and Validated by mRNA Analysis in Neuronal Ceroid Lipofuscinosis 7 Associated with a Novel Non-Canonical Splice Site Variant in MFSD8. Genes (Basel) 2023; 14:genes14020245. [PMID: 36833170 PMCID: PMC9956376 DOI: 10.3390/genes14020245] [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: 12/09/2022] [Revised: 01/08/2023] [Accepted: 01/16/2023] [Indexed: 01/19/2023] Open
Abstract
Neuronal ceroid lipofuscinoses (CNL) are lysosomal storage diseases that represent the most common cause of dementia in children. To date, 13 autosomal recessive (AR) and 1 autosomal dominant (AD) gene have been characterized. Biallelic variants in MFSD8 cause CLN7 type, with nearly 50 pathogenic variants, mainly truncating and missense, reported so far. Splice site variants require functional validation. We detected a novel homozygous non-canonical splice-site variant in MFSD8 in a 5-year-old girl who presented with progressive neurocognitive impairment and microcephaly. The diagnostic procedure was elicited by clinical genetics first, and then confirmed by cDNA sequencing and brain imaging. Inferred by the common geographic origin of the parents, an autosomal recessive inheritance was hypothesized, and SNP-array was performed as the first-line genetic test. Only three AR genes lying within the observed 24 Mb regions of homozygosity were consistent with the clinical phenotype, including EXOSC9, SPATA5 and MFSD8. The cerebral and cerebellar atrophy detected in the meantime by MRI, along with the suspicion of accumulation of ceroid lipopigment in neurons, prompted us to perform targeted MFSD8 sequencing. Following the detection of a splice site variant of uncertain significance, skipping of exon 8 was demonstrated by cDNA sequencing, and the variant was redefined as pathogenic.
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5
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Yap SQ, Kim WD, Huber RJ. Mfsd8 Modulates Growth and the Early Stages of Multicellular Development in Dictyostelium discoideum. Front Cell Dev Biol 2022; 10:930235. [PMID: 35756993 PMCID: PMC9218796 DOI: 10.3389/fcell.2022.930235] [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] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 05/23/2022] [Indexed: 11/17/2022] Open
Abstract
MFSD8 is a transmembrane protein that has been reported to transport chloride ions across the lysosomal membrane. Mutations in MFSD8 are associated with a subtype of Batten disease called CLN7 disease. Batten disease encompasses a family of 13 inherited neurodegenerative lysosomal storage diseases collectively referred to as the neuronal ceroid lipofuscinoses (NCLs). Previous work identified an ortholog of human MFSD8 in the social amoeba D. discoideum (gene: mfsd8, protein: Mfsd8), reported its localization to endocytic compartments, and demonstrated its involvement in protein secretion. In this study, we further characterized the effects of mfsd8 loss during D. discoideum growth and early stages of multicellular development. During growth, mfsd8− cells displayed increased rates of proliferation, pinocytosis, and expansion on bacterial lawns. Loss of mfsd8 also increased cell size, inhibited cytokinesis, affected the intracellular and extracellular levels of the quorum-sensing protein autocrine proliferation repressor A, and altered lysosomal enzyme activity. During the early stages of development, loss of mfsd8 delayed aggregation, which we determined was at least partly due to impaired cell-substrate adhesion, defects in protein secretion, and alterations in lysosomal enzyme activity. Overall, these results show that Mfsd8 plays an important role in modulating a variety of processes during the growth and early development of D. discoideum.
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Affiliation(s)
- Shyong Quan Yap
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON, Canada
| | - William D Kim
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON, Canada
| | - Robert J Huber
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON, Canada.,Department of Biology, Trent University, Peterborough, ON, Canada
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Lee J, Xu Y, Ye Y. Safeguarding Lysosomal Homeostasis by DNAJC5/CSPα-Mediated Unconventional Protein Secretion and Endosomal Microautophagy. Front Cell Dev Biol 2022; 10:906453. [PMID: 35620055 PMCID: PMC9127312 DOI: 10.3389/fcell.2022.906453] [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: 03/28/2022] [Accepted: 04/25/2022] [Indexed: 11/24/2022] Open
Abstract
Neuronal ceroid lipofuscinosis (NCL) is a collection of genetically inherited neurological disorders characterized by vision loss, seizure, brain death, and premature lethality. At the cellular level, a key pathologic hallmark of NCL is the build-up of autofluorescent storage materials (AFSM) in lysosomes of both neurons and non-neuronal cells. Molecular dissection of the genetic lesions underlying NCLs has shed significant insights into how disruption of lysosomal homeostasis may lead to lipofuscin accumulation and NCLs. Intriguingly, recent studies on DNAJC5/CSPα, a membrane associated HSC70 co-chaperone, have unexpectedly linked lipofuscin accumulation to two intimately coupled protein quality control processes at endolysosomes. This review discusses how deregulation of unconventional protein secretion and endosomal microautophagy (eMI) contributes to lipofuscin accumulation and neurodegeneration.
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Affiliation(s)
- Juhyung Lee
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Yue Xu
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Yihong Ye
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
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7
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Poncet AF, Grunewald O, Vaclavik V, Meunier I, Drumare I, Pelletier V, Bocquet B, Todorova MG, Le Moing AG, Devos A, Schorderet DF, Jobic F, Defoort-Dhellemmes S, Dollfus H, Smirnov VM, Dhaenens CM. Contribution of Whole-Genome Sequencing and Transcript Analysis to Decipher Retinal Diseases Associated with MFSD8 Variants. Int J Mol Sci 2022; 23:ijms23084294. [PMID: 35457110 PMCID: PMC9032189 DOI: 10.3390/ijms23084294] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 03/25/2022] [Accepted: 04/11/2022] [Indexed: 01/01/2023] Open
Abstract
Biallelic gene defects in MFSD8 are not only a cause of the late-infantile form of neuronal ceroid lipofuscinosis, but also of rare isolated retinal degeneration. We report clinical and genetic data of seven patients compound heterozygous or homozygous for variants in MFSD8, issued from a French cohort with inherited retinal degeneration, and two additional patients retrieved from a Swiss cohort. Next-generation sequencing of large panels combined with whole-genome sequencing allowed for the identification of twelve variants from which seven were novel. Among them were one deep intronic variant c.998+1669A>G, one large deletion encompassing exon 9 and 10, and a silent change c.750A>G. Transcript analysis performed on patients’ lymphoblastoid cell lines revealed the creation of a donor splice site by c.998+1669A>G, resulting in a 140 bp pseudoexon insertion in intron 10. Variant c.750A>G produced exon 8 skipping. In silico and in cellulo studies of these variants allowed us to assign the pathogenic effect, and showed that the combination of at least one severe variant with a moderate one leads to isolated retinal dystrophy, whereas the combination in trans of two severe variants is responsible for early onset severe retinal dystrophy in the context of late-infantile neuronal ceroid lipofuscinosis.
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Affiliation(s)
- Anaïs F. Poncet
- Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, F-59000 Lille, France; (A.F.P.); (O.G.); (A.D.)
| | - Olivier Grunewald
- Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, F-59000 Lille, France; (A.F.P.); (O.G.); (A.D.)
| | - Veronika Vaclavik
- University of Lausanne, Jules-Gonin Eye Hospital, 1004 Lausanne, Switzerland;
- Cantonal Hospital, Department of Ophthalmology, 1700 Fribourg, Switzerland
| | - Isabelle Meunier
- National Reference Centre for Inherited Sensory Diseases, University of Montpellier, Montpellier University Hospital, Sensgene Care Network, ERN-EYE Network, F-34000 Montpellier, France; (I.M.); (B.B.)
- Institute for Neurosciences of Montpellier (INM), University of Montpellier, INSERM, F-34000 Montpellier, France
| | - Isabelle Drumare
- Exploration de la Vision et Neuro-Ophtalmology, CHU de Lille, F-59000 Lille, France; (I.D.); (S.D.-D.); (V.M.S.)
| | - Valérie Pelletier
- Centre de Référence pour les Affections Rares en Génétique Ophtalmologiques, Hopitaux Universitaires de Strasbourg, F-67000 Strasbourg, France; (V.P.); (H.D.)
| | - Béatrice Bocquet
- National Reference Centre for Inherited Sensory Diseases, University of Montpellier, Montpellier University Hospital, Sensgene Care Network, ERN-EYE Network, F-34000 Montpellier, France; (I.M.); (B.B.)
- Institute for Neurosciences of Montpellier (INM), University of Montpellier, INSERM, F-34000 Montpellier, France
| | - Margarita G. Todorova
- Department of Ophthalmology, Cantonal Hospital, 9007 St. Gallen, Switzerland;
- Department of Ophthalmology, University of Zürich, 8091 Zürich, Switzerland
- Department of Ophthalmology, University of Basel, 4056 Basel, Switzerland
| | - Anne-Gaëlle Le Moing
- Department of Child Neurology, Amiens-Picardy University Hospital, F-80000 Amiens, France;
| | - Aurore Devos
- Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, F-59000 Lille, France; (A.F.P.); (O.G.); (A.D.)
| | - Daniel F. Schorderet
- Faculty of Biology and Medicine, University of Lausanne and Faculty of Life Sciences, Ecole Polytechnique Fédérale of Lausanne, 1004 Lausanne, Switzerland;
| | - Florence Jobic
- Unité de Génétique Médicale et Oncogénétique, Centre Hospitalier Universitaire Amiens Picardie, F-80000 Amiens, France;
| | - Sabine Defoort-Dhellemmes
- Exploration de la Vision et Neuro-Ophtalmology, CHU de Lille, F-59000 Lille, France; (I.D.); (S.D.-D.); (V.M.S.)
| | - Hélène Dollfus
- Centre de Référence pour les Affections Rares en Génétique Ophtalmologiques, Hopitaux Universitaires de Strasbourg, F-67000 Strasbourg, France; (V.P.); (H.D.)
| | - Vasily M. Smirnov
- Exploration de la Vision et Neuro-Ophtalmology, CHU de Lille, F-59000 Lille, France; (I.D.); (S.D.-D.); (V.M.S.)
- Université de Lille, Faculté de Médecine, F-59000 Lille, France
| | - Claire-Marie Dhaenens
- Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, F-59000 Lille, France; (A.F.P.); (O.G.); (A.D.)
- Correspondence: ; Tel.: +33-320444953
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8
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Chen X, Dong T, Hu Y, Shaffo FC, Belur NR, Mazzulli JR, Gray SJ. AAV9/MFSD8 gene therapy is effective in preclinical models of neuronal ceroid lipofuscinosis type 7 disease. J Clin Invest 2022; 132:146286. [PMID: 35025759 PMCID: PMC8884910 DOI: 10.1172/jci146286] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 01/11/2022] [Indexed: 11/17/2022] Open
Abstract
Neuronal ceroid lipofuscinosis type 7 (CLN7) disease is a lysosomal storage disease caused by mutations in the facilitator superfamily domain containing 8 (MFSD8) gene, which encodes a membrane-bound lysosomal protein, MFSD8. To test the effectiveness and safety of adeno-associated viral (AAV) gene therapy, an in vitro study demonstrated that AAV2/MFSD8 dose dependently rescued lysosomal function in fibroblasts from a CLN7 patient. An in vivo efficacy study using intrathecal administration of AAV9/MFSD8 to Mfsd8- /- mice at P7-P10 or P120 with high or low dose led to clear age- and dose-dependent effects. A high dose of AAV9/MFSD8 at P7-P10 resulted in widespread MFSD8 mRNA expression, tendency of amelioration of subunit c of mitochondrial ATP synthase accumulation and glial fibrillary acidic protein immunoreactivity, normalization of impaired behaviors, doubled median life span, and extended normal body weight gain. In vivo safety studies in rodents concluded that intrathecal administration of AAV9/MFSD8 was safe and well tolerated. In summary, these results demonstrated that the AAV9/MFSD8 vector is both effective and safe in preclinical models.
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Affiliation(s)
- Xin Chen
- Department of Pediatrics, University of Texas Southwestern (UTSW) Medical Center, Dallas, Texas, USA
| | - Thomas Dong
- Department of Pediatrics, University of Texas Southwestern (UTSW) Medical Center, Dallas, Texas, USA
| | - Yuhui Hu
- Department of Pediatrics, University of Texas Southwestern (UTSW) Medical Center, Dallas, Texas, USA
| | - Frances C Shaffo
- Department of Pediatrics, University of Texas Southwestern (UTSW) Medical Center, Dallas, Texas, USA
| | - Nandkishore R Belur
- The Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Joseph R Mazzulli
- The Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Steven J Gray
- Department of Pediatrics, University of Texas Southwestern (UTSW) Medical Center, Dallas, Texas, USA
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9
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A Novel, Apparently Silent Variant in MFSD8 Causes Neuronal Ceroid Lipofuscinosis with Marked Intrafamilial Variability. Int J Mol Sci 2022; 23:ijms23042271. [PMID: 35216386 PMCID: PMC8877174 DOI: 10.3390/ijms23042271] [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: 01/24/2022] [Revised: 02/09/2022] [Accepted: 02/16/2022] [Indexed: 02/06/2023] Open
Abstract
Variants in MFSD8 can cause neuronal ceroid lipofuscinoses (NCLs) as well as nonsyndromic retinopathy. The mutation spectrum includes mainly missense and stop variants, but splice sites and frameshift variants have also been reported. To date, apparently synonymous substitutions have not been shown to cause MFSD8-associated diseases. We report two closely related subjects from a consanguineous Turkish family who presented classical features of NCLs but demonstrated marked intrafamilial variability in age at the onset and severity of symptoms. In fact, the difference in the onset of first neurologic symptoms was 15 years and that of ophthalmologic symptoms was 12 years. One subject presented an intellectual disability and a considerable cerebellar ataxia syndrome, while the other subject showed no intellectual disability and only a mild atactic syndrome. The diagnostic genetic testing of both subjects based on genome sequencing prioritized a novel, apparently synonymous variant in MFSD8, which was found in homozygosity in both subjects. The variant was not located within an integral part of the splice site consensus sequences. However, the bioinformatic analyses suggested that the mutant allele is more likely to cause exon skipping due to an altered ratio of exonic splice enhancer and silencer motifs. Exon skipping was confirmed in vitro by minigene assays and in vivo by RNA analysis from patient lymphocytes. The mutant transcript is predicted to result in a frameshift and, if translated, in a truncated protein. Synonymous variants are often given a low priority in genetic diagnostics because of their expected lack of functional impact. This study highlights the importance of investigating the impact of synonymous variants on splicing.
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10
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Qiao Y, Gu Y, Cheng Y, Su Y, Lv N, Shang Q, Xing Q. Case Report: Novel MFSD8 Variants in a Chinese Family With Neuronal Ceroid Lipofuscinoses 7. Front Genet 2022; 13:807515. [PMID: 35154277 PMCID: PMC8826235 DOI: 10.3389/fgene.2022.807515] [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: 11/02/2021] [Accepted: 01/06/2022] [Indexed: 11/24/2022] Open
Abstract
Neuronal ceroid lipofuscinoses (NCLs) are among the most common progressive encephalopathies of childhood. Neuronal ceroid lipofuscinosis 7 (CLN7), one of the late infantile-onset NCLs, is an autosomal recessive disorder caused by mutations in the MFSD8 gene on chromosome 4q28. Almost all reported mutations of MFSD8 in CLN7 patients were SNVs. However, we report a 4-year-old boy with CLN7 harboring compound heterozygous mutations in the MFSD8 gene, including one novel two-nucleotide deletion c.136_137delAT (p. M46Vfs*22) and one whole gene deletion of MFSD8 confirmed by Sanger sequencing, genomic quantitative PCR and CNV-seq. Therefore, for nonconsanguineous CLN7 patients with homozygous mutations in the MFSD8 gene, genetic counseling staff should focus on the possibility of whole gene deletion. This is one case report describing a whole gene deletion in a Chinese patient with CLN7, suggesting the diagnosis of CLN7 should be based on clinical suspicion and genetic testing.
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Affiliation(s)
- Yimeng Qiao
- Institutes of Biomedical Sciences and Children's Hospital, Fudan University, Shanghai, China
| | - Yang Gu
- Children's Hospital of Zhengzhou University and Henan Children's Hospital, Zhengzhou, China
| | - Ye Cheng
- Institutes of Biomedical Sciences and Children's Hospital, Fudan University, Shanghai, China
| | - Yu Su
- Institutes of Biomedical Sciences and Children's Hospital, Fudan University, Shanghai, China
| | - Nan Lv
- Children's Hospital of Zhengzhou University and Henan Children's Hospital, Zhengzhou, China
| | - Qing Shang
- Children's Hospital of Zhengzhou University and Henan Children's Hospital, Zhengzhou, China
| | - Qinghe Xing
- Institutes of Biomedical Sciences and Children's Hospital, Fudan University, Shanghai, China.,Shanghai Center for Women and Children's Health, Shanghai, China
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11
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Lopez-Fabuel I, Garcia-Macia M, Buondelmonte C, Burmistrova O, Bonora N, Alonso-Batan P, Morant-Ferrando B, Vicente-Gutierrez C, Jimenez-Blasco D, Quintana-Cabrera R, Fernandez E, Llop J, Ramos-Cabrer P, Sharaireh A, Guevara-Ferrer M, Fitzpatrick L, Thompton CD, McKay TR, Storch S, Medina DL, Mole SE, Fedichev PO, Almeida A, Bolaños JP. Aberrant upregulation of the glycolytic enzyme PFKFB3 in CLN7 neuronal ceroid lipofuscinosis. Nat Commun 2022; 13:536. [PMID: 35087090 PMCID: PMC8795187 DOI: 10.1038/s41467-022-28191-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 01/12/2022] [Indexed: 02/06/2023] Open
Abstract
CLN7 neuronal ceroid lipofuscinosis is an inherited lysosomal storage neurodegenerative disease highly prevalent in children. CLN7/MFSD8 gene encodes a lysosomal membrane glycoprotein, but the biochemical processes affected by CLN7-loss of function are unexplored thus preventing development of potential treatments. Here, we found, in the Cln7∆ex2 mouse model of CLN7 disease, that failure in autophagy causes accumulation of structurally and bioenergetically impaired neuronal mitochondria. In vivo genetic approach reveals elevated mitochondrial reactive oxygen species (mROS) in Cln7∆ex2 neurons that mediates glycolytic enzyme PFKFB3 activation and contributes to CLN7 pathogenesis. Mechanistically, mROS sustains a signaling cascade leading to protein stabilization of PFKFB3, normally unstable in healthy neurons. Administration of the highly selective PFKFB3 inhibitor AZ67 in Cln7∆ex2 mouse brain in vivo and in CLN7 patients-derived cells rectifies key disease hallmarks. Thus, aberrant upregulation of the glycolytic enzyme PFKFB3 in neurons may contribute to CLN7 pathogenesis and targeting PFKFB3 could alleviate this and other lysosomal storage diseases.
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Affiliation(s)
- Irene Lopez-Fabuel
- Institute of Functional Biology and Genomics (IBFG), Universidad de Salamanca, CSIC, Salamanca, Spain.
- Institute of Biomedical Research of Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain.
| | - Marina Garcia-Macia
- Institute of Functional Biology and Genomics (IBFG), Universidad de Salamanca, CSIC, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Madrid, Spain
| | - Costantina Buondelmonte
- Institute of Functional Biology and Genomics (IBFG), Universidad de Salamanca, CSIC, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain
| | | | - Nicolo Bonora
- Institute of Functional Biology and Genomics (IBFG), Universidad de Salamanca, CSIC, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain
| | - Paula Alonso-Batan
- Institute of Functional Biology and Genomics (IBFG), Universidad de Salamanca, CSIC, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain
| | - Brenda Morant-Ferrando
- Institute of Functional Biology and Genomics (IBFG), Universidad de Salamanca, CSIC, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain
| | - Carlos Vicente-Gutierrez
- Institute of Functional Biology and Genomics (IBFG), Universidad de Salamanca, CSIC, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Madrid, Spain
| | - Daniel Jimenez-Blasco
- Institute of Functional Biology and Genomics (IBFG), Universidad de Salamanca, CSIC, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Madrid, Spain
| | - Ruben Quintana-Cabrera
- Institute of Functional Biology and Genomics (IBFG), Universidad de Salamanca, CSIC, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Madrid, Spain
| | - Emilio Fernandez
- Institute of Functional Biology and Genomics (IBFG), Universidad de Salamanca, CSIC, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Madrid, Spain
| | - Jordi Llop
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), Donostia-San Sebastián, Spain
| | - Pedro Ramos-Cabrer
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), Donostia-San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, Bilbao, Spain
| | - Aseel Sharaireh
- Centre for Bioscience, Manchester Metropolitan University, Manchester, M1 5GD, UK
| | - Marta Guevara-Ferrer
- Centre for Bioscience, Manchester Metropolitan University, Manchester, M1 5GD, UK
| | - Lorna Fitzpatrick
- Centre for Bioscience, Manchester Metropolitan University, Manchester, M1 5GD, UK
| | | | - Tristan R McKay
- Centre for Bioscience, Manchester Metropolitan University, Manchester, M1 5GD, UK
| | - Stephan Storch
- University Children's Research@Kinder-UKE, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Diego L Medina
- Telethon Institute of Genetics and Medicine (TIGEM), High Content Screening Facility, Via Campi Flegrei 34, 80078, Pozzuoli, Italy
- Medical Genetics Unit, Department of Medical and Translational Science, Federico II University, 80138, Naples, Italy
| | - Sara E Mole
- MRC Laboratory for Molecular Biology and GOS Institute of Child Health, University College London, London, UK
| | | | - Angeles Almeida
- Institute of Functional Biology and Genomics (IBFG), Universidad de Salamanca, CSIC, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain
| | - Juan P Bolaños
- Institute of Functional Biology and Genomics (IBFG), Universidad de Salamanca, CSIC, Salamanca, Spain.
- Institute of Biomedical Research of Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain.
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Madrid, Spain.
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12
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Francelle L, Mazzulli JR. Neuroinflammation in aucher disease, neuronal ceroid lipofuscinosis, and commonalities with Parkinson’s disease. Brain Res 2022; 1780:147798. [PMID: 35063468 PMCID: PMC9126024 DOI: 10.1016/j.brainres.2022.147798] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 01/05/2022] [Accepted: 01/13/2022] [Indexed: 12/13/2022]
Abstract
Lysosomal storage diseases (LSDs) are rare genetic disorders caused by a disruption in cellular clearance, resulting in pathological storage of undegraded lysosomal substrates. Recent clinical and genetic studies have uncovered links between multiple LSDs and common neurodegenerative diseases such as Parkinson's disease (PD). Here, we review recent literature describing the role of glia cells and neuroinflammation in PD and LSDs, including Gaucher disease (GD) and neuronal ceroid lipofuscinosis (NCL), and highlight converging inflammation pathways that lead to neuron loss. Recent data indicates that lysosomal dysfunction and accumulation of storage materials can initiate the activation of glial cells, through interaction with cell surface or cytosolic pattern recognition receptors that detect pathogenic aggregates of cellular debris. Activated glia cells could act to protect neurons through the elimination of toxic protein or lipid aggregates early in the disease process. However prolonged glial activation that occurs over several decades in chronic-age related neurodegeneration could induce the inappropriate elimination of synapses, leading to neuron loss. These studies provide mechanistic insight into the relationship between lysosomal dysfunction and glial activation, and offer novel therapeutic pathways for the treatment of PD and LSDs focused on reducing neuroinflammation and mitigating cell loss.
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13
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Wang Y, Zeng W, Lin B, Yao Y, Li C, Hu W, Wu H, Huang J, Zhang M, Xue T, Ren D, Qu L, Cang C. CLN7 is an organellar chloride channel regulating lysosomal function. SCIENCE ADVANCES 2021; 7:eabj9608. [PMID: 34910516 PMCID: PMC8673761 DOI: 10.1126/sciadv.abj9608] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Neuronal ceroid lipofuscinoses (NCLs) are a group of autosomal recessive lysosomal storage diseases. One variant form of late-infantile NCL (vLINCL) is caused by mutations of a lysosomal membrane protein CLN7, the function of which has remained unknown. Here, we identified CLN7 as a novel endolysosomal chloride channel. Overexpression of CLN7 increases endolysosomal chloride currents and enlarges endolysosomes through a Ca2+/calmodulin-dependent way. Human CLN7 and its yeast homolog exhibit characteristics of chloride channels and are sensitive to chloride channel blockers. Moreover, CLN7 regulates lysosomal chloride conductance, luminal pH, and lysosomal membrane potential and promotes the release of lysosomal Ca2+ through transient receptor potential mucolipin 1 (TRPML1). Knocking out CLN7 causes pathological features that are similar to those of patients with vLINCL, including retinal degeneration and autofluorescent lipofuscin. The pathogenic mutations in CLN7 lead to a decrease in chloride permeability, suggesting that reconstitution of lysosomal Cl− homeostasis may be an effective strategy for the treatment of vLINCL.
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Affiliation(s)
- Yayu Wang
- Hefei National Laboratory for Physical Sciences at Microscale, the CAS Key Laboratory of Innate Immunity and Chronic Disease, Neurodegenerative Disorder Research Center, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Wenping Zeng
- Hefei National Laboratory for Physical Sciences at Microscale, the CAS Key Laboratory of Innate Immunity and Chronic Disease, Neurodegenerative Disorder Research Center, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Bingqian Lin
- Hefei National Laboratory for Physical Sciences at Microscale, the CAS Key Laboratory of Innate Immunity and Chronic Disease, Neurodegenerative Disorder Research Center, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yichuan Yao
- CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Canjun Li
- Hefei National Laboratory for Physical Sciences at Microscale, the CAS Key Laboratory of Innate Immunity and Chronic Disease, Neurodegenerative Disorder Research Center, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Wenqi Hu
- Hefei National Laboratory for Physical Sciences at Microscale, the CAS Key Laboratory of Innate Immunity and Chronic Disease, Neurodegenerative Disorder Research Center, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Haotian Wu
- Hefei National Laboratory for Physical Sciences at Microscale, the CAS Key Laboratory of Innate Immunity and Chronic Disease, Neurodegenerative Disorder Research Center, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jiamin Huang
- Hefei National Laboratory for Physical Sciences at Microscale, the CAS Key Laboratory of Innate Immunity and Chronic Disease, Neurodegenerative Disorder Research Center, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Mei Zhang
- CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Tian Xue
- Hefei National Laboratory for Physical Sciences at Microscale, the CAS Key Laboratory of Innate Immunity and Chronic Disease, Neurodegenerative Disorder Research Center, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Dejian Ren
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Lili Qu
- Hefei National Laboratory for Physical Sciences at Microscale, the CAS Key Laboratory of Innate Immunity and Chronic Disease, Neurodegenerative Disorder Research Center, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
- Corresponding author. (L.Q.); (C.C.)
| | - Chunlei Cang
- Hefei National Laboratory for Physical Sciences at Microscale, the CAS Key Laboratory of Innate Immunity and Chronic Disease, Neurodegenerative Disorder Research Center, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
- Corresponding author. (L.Q.); (C.C.)
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14
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Zhu F, Miao Y, Cheng M, Ye X, Chen A, Zheng G, Tian X. The CACNA1A Mutant Disrupts Lysosome Calcium Homeostasis in Cerebellar Neurons and the Resulting Endo-Lysosomal Fusion Defect Can be Improved by Calcium Modulation. Neurochem Res 2021; 47:249-263. [PMID: 34476720 DOI: 10.1007/s11064-021-03438-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 08/23/2021] [Accepted: 08/25/2021] [Indexed: 11/24/2022]
Abstract
Mutations in P/Q type voltage gated calcium channel (VGCC) lead severe human neurological diseases such as episodic ataxia 2, familial hemiplegic migraine 1, absence epilepsy, progressive ataxia and spinocerebellar ataxia 6. The pathogenesis of these diseases remains unclear. Mice with spontaneous mutation in the Cacna1a gene encoding the pore-forming subunit of P/Q type VGCC also exhibit ataxia, epilepsy and neurodegeneration. Based on the previous work showing that the P/Q type VGCC in neurons regulates lysosomal fusion through its calcium channel activity on lysosomes, we utilized CACNA1A mutant mice to further investigate the mechanism by which P/Q-type VGCCs regulate lysosomal function and neuronal homeostasis. We found CACNA1A mutant neurons have reduced lysosomal calcium storage without changing the resting calcium concentration in cytoplasm and the acidification of lysosomes. Immunohistochemistry and transmission electron microscopy reveal axonal degeneration due to lysosome dysfunction in the CACNA1A mutant cerebella. The calcium modulating drug thapsigargin, by depleting the ER calcium store, which locally increases the calcium concentration can alleviate the defective lysosomal fusion in mutant neurons. We propose a model that in cerebellar neurons, P/Q-type VGCC maintains the integrity of the nervous system by regulating lysosomal calcium homeostasis to affect lysosomal fusion, which in turn regulates multiple important cellular processes such as autophagy and endocytosis. This study helps us to better understand the pathogenesis of P/Q-type VGCC related neurodegenerative diseases and provides a feasible direction for future pharmacological treatment.
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Affiliation(s)
- Feng Zhu
- Key Laboratory of Neuropsychiatric Drug Research of Zhejiang Province, Institute of Materia Medica, Hangzhou Medical College (Zhejiang Academy of Medical Sciences), Hangzhou, 310013, China.,Department of Pharmacy, Hangzhou Medical College, Hangzhou, 310013, China
| | - Yunping Miao
- Key Laboratory of Neuropsychiatric Drug Research of Zhejiang Province, Institute of Materia Medica, Hangzhou Medical College (Zhejiang Academy of Medical Sciences), Hangzhou, 310013, China.,Department of Pharmacy, Hangzhou Medical College, Hangzhou, 310013, China
| | - Min Cheng
- Key Laboratory of Neuropsychiatric Drug Research of Zhejiang Province, Institute of Materia Medica, Hangzhou Medical College (Zhejiang Academy of Medical Sciences), Hangzhou, 310013, China.,Department of Pharmacy, Hangzhou Medical College, Hangzhou, 310013, China
| | - Xiaodi Ye
- Key Laboratory of Neuropsychiatric Drug Research of Zhejiang Province, Institute of Materia Medica, Hangzhou Medical College (Zhejiang Academy of Medical Sciences), Hangzhou, 310013, China.,Department of Pharmacy, Hangzhou Medical College, Hangzhou, 310013, China
| | - Aiying Chen
- Key Laboratory of Neuropsychiatric Drug Research of Zhejiang Province, Institute of Materia Medica, Hangzhou Medical College (Zhejiang Academy of Medical Sciences), Hangzhou, 310013, China.,Department of Pharmacy, Hangzhou Medical College, Hangzhou, 310013, China
| | - Gaoli Zheng
- National Zhejiang Center for Safety Evaluation of New Drugs, Hangzhou Medical College (Zhejiang Academy of Medical Sciences), Hangzhou, 310013, China
| | - Xuejun Tian
- Key Laboratory of Neuropsychiatric Drug Research of Zhejiang Province, Institute of Materia Medica, Hangzhou Medical College (Zhejiang Academy of Medical Sciences), Hangzhou, 310013, China. .,Department of Pharmacy, Hangzhou Medical College, Hangzhou, 310013, China. .,Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, 310058, China.
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15
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Graceffa V. Clinical Development of Cell Therapies to Halt Lysosomal Storage Diseases: Results and Lessons Learned. Curr Gene Ther 2021; 22:191-213. [PMID: 34323185 DOI: 10.2174/1566523221666210728141924] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 05/31/2021] [Accepted: 06/13/2021] [Indexed: 11/22/2022]
Abstract
Although cross-correction was discovered more than 50 years ago, and held the promise of drastically improving disease management, still no cure exists for lysosomal storage diseases (LSDs). Cell therapies hold the potential to halt disease progression: either a subset of autologous cells can be ex vivo/ in vivo transfected with the functional gene or allogenic wild type stem cells can be transplanted. However, majority of cell-based attempts have been ineffective, due to the difficulties in reversing neuronal symptomatology, in finding appropriate gene transfection approaches, in inducing immune tolerance, reducing the risk of graft versus host disease (GVHD) when allogenic cells are used and that of immune response when engineered viruses are administered, coupled with a limited secretion and uptake of some enzymes. In the last decade, due to advances in our understanding of lysosomal biology and mechanisms of cross-correction, coupled with progresses in gene therapy, ongoing pre-clinical and clinical investigations have remarkably increased. Even gene editing approaches are currently under clinical experimentation. This review proposes to critically discuss and compare trends and advances in cell-based and gene therapy for LSDs. Systemic gene delivery and transplantation of allogenic stem cells will be initially discussed, whereas proposed brain targeting methods will be then critically outlined.
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Affiliation(s)
- Valeria Graceffa
- Cellular Health and Toxicology Research Group (CHAT), Institute of Technology Sligo, Ash Ln, Bellanode, Sligo, Ireland
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16
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Crain AM, Kitchen DL, Godiyal N, Pfeifer CM. MRI findings in neuronal ceroid lipofuscinosis. Radiol Case Rep 2020; 15:2375-2377. [PMID: 32994845 PMCID: PMC7515973 DOI: 10.1016/j.radcr.2020.09.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 09/08/2020] [Accepted: 09/09/2020] [Indexed: 12/05/2022] Open
Abstract
Neuronal ceroid lipofuscinosis is a rare cause for developmental delay and seizures that results in neurodegeneration. Presented here is a case of a 5-year-old male who presented for MRI following a delay in achieving developmental milestones and epilepsy. MRI was performed demonstrating a thinned corpus callosum and generalized low parenchymal volume with periventricular gliosis. Magnetic resonance spectroscopy showed glutamate/glutamine accumulation and diminished N-acetylaspartate. The diagnosis of neuronal ceroid lipofusciosis was revealed following genetic testing. This case is useful in showing findings of this rare disorder.
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Affiliation(s)
- Anna M. Crain
- University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX 75080
| | - Deanna L. Kitchen
- Department of Radiology, University of Texas Southwestern Medical Center,5323 Harry Hines Blvd, Dallas, TX 75390
| | - Nikhil Godiyal
- University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX 75080
| | - Cory M. Pfeifer
- Department of Radiology, University of Texas Southwestern Medical Center,5323 Harry Hines Blvd, Dallas, TX 75390
- Corresponding author. (C.M. Pfeifer)
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17
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Butz ES, Chandrachud U, Mole SE, Cotman SL. Moving towards a new era of genomics in the neuronal ceroid lipofuscinoses. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165571. [DOI: 10.1016/j.bbadis.2019.165571] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Revised: 10/12/2019] [Accepted: 10/14/2019] [Indexed: 12/15/2022]
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18
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Huber RJ, Mathavarajah S, Yap SQ. Mfsd8 localizes to endocytic compartments and influences the secretion of Cln5 and cathepsin D in Dictyostelium. Cell Signal 2020; 70:109572. [PMID: 32087303 DOI: 10.1016/j.cellsig.2020.109572] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 02/14/2020] [Accepted: 02/17/2020] [Indexed: 12/13/2022]
Abstract
The neuronal ceroid lipofuscinoses (NCLs) are a family of neurodegenerative diseases that affect people of all ages and ethnicities, yet many of the associated genes/proteins are not well characterized. Mutations in MFSD8 (major facilitator superfamily domain-containing 8) cause an infantile form of NCL referred to as CLN7 disease. In this study, we revealed the localization and binding partners of an ortholog of human MFSD8 (Mfsd8) in the social amoeba Dictyostelium discoideum. Putative lysosomal targeting motifs are conserved in Dictyostelium Mfsd8, as are several residues mutated in CLN7 disease patients. Mfsd8 tagged with GFP localizes to endocytic compartments, which includes acidic intracellular vesicles and late endosomes. We pulled-down GFP-Mfsd8 and used mass spectrometry to reveal the Mfsd8 interactome during Dictyostelium growth and starvation. Among the identified hits were the Dictyostelium ortholog of human cathepsin D (CtsD), as well as proteins linked to the functions of the CLN3 (Cln3) and CLN5 (Cln5) orthologs in Dictyostelium. To study the function of Mfsd8, we validated a publically available mfsd8- cell line (GWDI Project) and then used this knockout cell line to show that Mfsd8 influences the secretion of Cln5 and CtsD. This information is then integrated into an emerging model describing the molecular networking of NCL proteins in Dictyostelium. In total, this study identifies Dictyostelium as a new model system for studying CLN7 disease.
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Affiliation(s)
- Robert J Huber
- Department of Biology, Trent University, Peterborough, Ontario, Canada.
| | | | - Shyong Quan Yap
- Department of Biology, Trent University, Peterborough, Ontario, Canada
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19
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Bauwens M, Storch S, Weisschuh N, Ceuterick‐de Groote C, De Rycke R, Guillemyn B, De Jaegere S, Coppieters F, Van Coster R, Leroy BP, De Baere E. Functional characterization of novel MFSD8 pathogenic variants anticipates neurological involvement in juvenile isolated maculopathy. Clin Genet 2020; 97:426-436. [PMID: 31721179 PMCID: PMC7064892 DOI: 10.1111/cge.13673] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 10/30/2019] [Accepted: 11/01/2019] [Indexed: 12/22/2022]
Abstract
Biallelic MFSD8 variants are an established cause of severe late-infantile subtype of neuronal ceroid lipofuscinosis (v-LINCL), a severe lysosomal storage disorder, but have also been associated with nonsyndromic adult-onset maculopathy. Here, we functionally characterized two novel MFSD8 variants found in a child with juvenile isolated maculopathy, in order to establish a refined prognosis. ABCA4 locus resequencing was followed by the analysis of other inherited retinal disease genes by whole exome sequencing (WES). Minigene assays and cDNA sequencing were used to assess the effect of a novel MFSD8 splice variant. MFSD8 expression was quantified with qPCR and overexpression studies were analyzed by immunoblotting. Transmission electron microscopy (TEM) was performed on a skin biopsy and ophthalmological and neurological re-examinations were conducted. WES revealed two novel MFSD8 variants: c.[590del];[439+3A>C] p.[Gly197Valfs*2];[Ile67Glufs*3]. Characterization of the c.439+3A>C variant via splice assays showed exon-skipping (p.Ile67Glufs*3), while overexpression studies of the corresponding protein indicated expression of a truncated polypeptide. In addition, a significantly reduced MFSD8 RNA expression was noted in patient's lymphocytes. TEM of a skin biopsy revealed typical v-LINCL lipopigment inclusions while neurological imaging of the proband displayed subtle cerebellar atrophy. Functional characterization demonstrated the pathogenicity of two novel MFSD8 variants, found in a child with an initial diagnosis of juvenile isolated maculopathy but likely evolving to v-LINCL with a protracted disease course. Our study allowed a refined neurological prognosis in the proband and expands the natural history of MFSD8-associated disease.
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Affiliation(s)
| | - Stephan Storch
- Department of Biochemistry, Children's HospitalUniversity Medical Center Hamburg‐EppendorfHamburgGermany
| | - Nicole Weisschuh
- Molecular Genetics Laboratory, Institute for Ophthalmic ResearchUniversity of TuebingenTuebingenGermany
| | | | - Riet De Rycke
- Department of Biomedical Molecular BiologyGhent UniversityGhentBelgium
- VIB‐UGent Center for Inflammation ResearchGhentBelgium
- Ghent University Expertise Centre for Transmission Electron Microscopy and VIB BioImaging CoreGhentBelgium
| | | | - Sarah De Jaegere
- Center for Medical GeneticsGhent University HospitalGhentBelgium
| | | | - Rudy Van Coster
- Department of Pediatrics, Division of Pediatric Neurology and MetabolismGhent University HospitalGhentBelgium
| | - Bart P. Leroy
- Center for Medical GeneticsGhent University HospitalGhentBelgium
- Department of OphthalmologyGhent University and Ghent University HospitalGhentBelgium
- Division of Ophthalmology and Center for Cellular & Molecular TherapeuticsThe Children's Hospital of PhiladelphiaPhiladelphiaPennsylvania
| | - Elfride De Baere
- Center for Medical GeneticsGhent UniversityGhentBelgium
- Center for Medical GeneticsGhent University HospitalGhentBelgium
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20
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Connolly KJ, O'Hare MB, Mohammed A, Aitchison KM, Anthoney NC, Taylor MJ, Stewart BA, Tuxworth RI, Tear G. The neuronal ceroid lipofuscinosis protein Cln7 functions in the postsynaptic cell to regulate synapse development. Sci Rep 2019; 9:15592. [PMID: 31666534 PMCID: PMC6821864 DOI: 10.1038/s41598-019-51588-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 10/03/2019] [Indexed: 02/08/2023] Open
Abstract
The neuronal ceroid lipofuscinoses (NCLs) are a group of fatal, monogenic neurodegenerative disorders with an early onset in infancy or childhood. Despite identification of the genes disrupted in each form of the disease, their normal cellular role and how their deficits lead to disease pathology is not fully understood. Cln7, a major facilitator superfamily domain-containing protein, is affected in a late infantile-onset form of NCL. Cln7 is conserved across species suggesting a common function. Here we demonstrate that Cln7 is required for the normal growth of synapses at the Drosophila larval neuromuscular junction. In a Cln7 mutant, synapses fail to develop fully leading to reduced function and behavioral changes with dysregulation of TOR activity. Cln7 expression is restricted to the post-synaptic cell and the protein localizes to vesicles immediately adjacent to the post-synaptic membrane. Our data suggest an involvement for Cln7 in regulating trans-synaptic communication necessary for normal synapse development.
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Affiliation(s)
- Kyle J Connolly
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Megan B O'Hare
- Department of Developmental Neurobiology, King's College London, New Hunt's House, London, SE1 1UL, UK
| | - Alamin Mohammed
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Katelyn M Aitchison
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Niki C Anthoney
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Matthew J Taylor
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Bryan A Stewart
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Richard I Tuxworth
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
| | - Guy Tear
- Department of Developmental Neurobiology, King's College London, New Hunt's House, London, SE1 1UL, UK.
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21
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von Kleist L, Ariunbat K, Braren I, Stauber T, Storch S, Danyukova T. A newly generated neuronal cell model of CLN7 disease reveals aberrant lysosome motility and impaired cell survival. Mol Genet Metab 2019; 126:196-205. [PMID: 30301600 DOI: 10.1016/j.ymgme.2018.09.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 09/26/2018] [Accepted: 09/26/2018] [Indexed: 01/11/2023]
Abstract
Mutations in the CLN7/MFSD8 gene encoding the lysosomal membrane protein CLN7 are causative of CLN7 disease, an inherited neurodegenerative disorder that typically affects children. To gain insight into the pathomechanisms of CLN7 disease, we established an immortalized cell line based on cerebellar (Cb) granule neuron precursors isolated from Cln7-/- mice. Here, we demonstrate that Cln7-deficient neuron-derived Cb cells display an abnormal phenotype that includes increased size and defective outward movement of late endosomes and lysosomes as well as impaired lysosomal exocytosis. Whereas Cln7-/- Cb cells appeared to be autophagy-competent, loss of Cln7 resulted in enhanced cell death under prolonged nutrient deprivation. Furthermore, reduced cell survival of Cln7-deficient cells was accompanied by a significantly impaired protein kinase B/Akt phosphorylation at Ser473 during long-term starvation. In summary, our data demonstrate for the first time that the putative lysosomal transporter CLN7 is relevant for lysosome motility and plays an important role for neuronal cell survival under conditions of starvation.
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Affiliation(s)
- Lisa von Kleist
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany.
| | - Khandsuren Ariunbat
- Section Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
| | - Ingke Braren
- Vector Core Unit, Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
| | - Tobias Stauber
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany.
| | - Stephan Storch
- Section Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
| | - Tatyana Danyukova
- Section Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
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22
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Mukherjee AB, Appu AP, Sadhukhan T, Casey S, Mondal A, Zhang Z, Bagh MB. Emerging new roles of the lysosome and neuronal ceroid lipofuscinoses. Mol Neurodegener 2019; 14:4. [PMID: 30651094 PMCID: PMC6335712 DOI: 10.1186/s13024-018-0300-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 12/04/2018] [Indexed: 12/04/2022] Open
Abstract
Neuronal Ceroid Lipofuscinoses (NCLs), commonly known as Batten disease, constitute a group of the most prevalent neurodegenerative lysosomal storage disorders (LSDs). Mutations in at least 13 different genes (called CLNs) cause various forms of NCLs. Clinically, the NCLs manifest early impairment of vision, progressive decline in cognitive and motor functions, seizures and a shortened lifespan. At the cellular level, all NCLs show intracellular accumulation of autofluorescent material (called ceroid) and progressive neuron loss. Despite intense studies the normal physiological functions of each of the CLN genes remain poorly understood. Consequently, the development of mechanism-based therapeutic strategies remains challenging. Endolysosomal dysfunction contributes to pathogenesis of virtually all LSDs. Studies within the past decade have drastically changed the notion that the lysosomes are merely the terminal degradative organelles. The emerging new roles of the lysosome include its central role in nutrient-dependent signal transduction regulating metabolism and cellular proliferation or quiescence. In this review, we first provide a brief overview of the endolysosomal and autophagic pathways, lysosomal acidification and endosome-lysosome and autophagosome-lysosome fusions. We emphasize the importance of these processes as their dysregulation leads to pathogenesis of many LSDs including the NCLs. We also describe what is currently known about each of the 13 CLN genes and their products and how understanding the emerging new roles of the lysosome may clarify the underlying pathogenic mechanisms of the NCLs. Finally, we discuss the current and emerging therapeutic strategies for various NCLs.
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Affiliation(s)
- Anil B. Mukherjee
- Section on Developmental Genetics, Program on Endocrinology and Molecular Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, Maryland 20892-1830 USA
| | - Abhilash P. Appu
- Section on Developmental Genetics, Program on Endocrinology and Molecular Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, Maryland 20892-1830 USA
| | - Tamal Sadhukhan
- Section on Developmental Genetics, Program on Endocrinology and Molecular Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, Maryland 20892-1830 USA
| | - Sydney Casey
- Section on Developmental Genetics, Program on Endocrinology and Molecular Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, Maryland 20892-1830 USA
| | - Avisek Mondal
- Section on Developmental Genetics, Program on Endocrinology and Molecular Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, Maryland 20892-1830 USA
| | - Zhongjian Zhang
- Section on Developmental Genetics, Program on Endocrinology and Molecular Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, Maryland 20892-1830 USA
- Present address: Institute of Psychiatry and Neuroscience, Xinxiang Medical University, Xinxiang, 453003 Henan China
| | - Maria B. Bagh
- Section on Developmental Genetics, Program on Endocrinology and Molecular Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, Maryland 20892-1830 USA
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23
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Geier EG, Bourdenx M, Storm NJ, Cochran JN, Sirkis DW, Hwang JH, Bonham LW, Ramos EM, Diaz A, Van Berlo V, Dokuru D, Nana AL, Karydas A, Balestra ME, Huang Y, Russo SP, Spina S, Grinberg LT, Seeley WW, Myers RM, Miller BL, Coppola G, Lee SE, Cuervo AM, Yokoyama JS. Rare variants in the neuronal ceroid lipofuscinosis gene MFSD8 are candidate risk factors for frontotemporal dementia. Acta Neuropathol 2019; 137:71-88. [PMID: 30382371 PMCID: PMC6371791 DOI: 10.1007/s00401-018-1925-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 10/23/2018] [Accepted: 10/24/2018] [Indexed: 12/21/2022]
Abstract
Pathogenic variation in MAPT, GRN, and C9ORF72 accounts for at most only half of frontotemporal lobar degeneration (FTLD) cases with a family history of neurological disease. This suggests additional variants and genes that remain to be identified as risk factors for FTLD. We conducted a case-control genetic association study comparing pathologically diagnosed FTLD patients (n = 94) to cognitively normal older adults (n = 3541), and found suggestive evidence that gene-wide aggregate rare variant burden in MFSD8 is associated with FTLD risk. Because homozygous mutations in MFSD8 cause neuronal ceroid lipofuscinosis (NCL), similar to homozygous mutations in GRN, we assessed rare variants in MFSD8 for relevance to FTLD through experimental follow-up studies. Using post-mortem tissue from middle frontal gyrus of patients with FTLD and controls, we identified increased MFSD8 protein levels in MFSD8 rare variant carriers relative to non-variant carrier patients with sporadic FTLD and healthy controls. We also observed an increase in lysosomal and autophagy-related proteins in MFSD8 rare variant carrier and sporadic FTLD patients relative to controls. Immunohistochemical analysis revealed that MFSD8 was expressed in neurons and astrocytes across subjects, without clear evidence of abnormal localization in patients. Finally, in vitro studies identified marked disruption of lysosomal function in cells from MFSD8 rare variant carriers, and identified one rare variant that significantly increased the cell surface levels of MFSD8. Considering the growing evidence for altered autophagy in the pathogenesis of neurodegenerative disorders, our findings support a role of NCL genes in FTLD risk and suggest that MFSD8-associated lysosomal dysfunction may contribute to FTLD pathology.
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Affiliation(s)
- Ethan G Geier
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA
| | - Mathieu Bourdenx
- Department of Development and Molecular Biology, Institute for Aging Studies, Albert Einstein College of Medicine, New York, NY, 10461, USA
| | - Nadia J Storm
- Department of Development and Molecular Biology, Institute for Aging Studies, Albert Einstein College of Medicine, New York, NY, 10461, USA
| | | | - Daniel W Sirkis
- Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Ji-Hye Hwang
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA
- Department of Pathology, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Luke W Bonham
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA
| | - Eliana Marisa Ramos
- Department of Psychiatry and Semel Institute for Neuroscience and Human Behavior, The David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Antonio Diaz
- Department of Development and Molecular Biology, Institute for Aging Studies, Albert Einstein College of Medicine, New York, NY, 10461, USA
| | - Victoria Van Berlo
- Department of Psychiatry and Semel Institute for Neuroscience and Human Behavior, The David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Deepika Dokuru
- Department of Psychiatry and Semel Institute for Neuroscience and Human Behavior, The David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Alissa L Nana
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA
| | - Anna Karydas
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA
| | | | - Yadong Huang
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA
- Department of Pathology, University of California, San Francisco, San Francisco, CA, 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Silvia P Russo
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA
| | - Salvatore Spina
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA
- Department of Pathology, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Lea T Grinberg
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA
- Department of Pathology, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - William W Seeley
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA
- Department of Pathology, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Richard M Myers
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, 35806, USA
| | - Bruce L Miller
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA
| | - Giovanni Coppola
- Department of Psychiatry and Semel Institute for Neuroscience and Human Behavior, The David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Suzee E Lee
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA
| | - Ana Maria Cuervo
- Department of Development and Molecular Biology, Institute for Aging Studies, Albert Einstein College of Medicine, New York, NY, 10461, USA
| | - Jennifer S Yokoyama
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA.
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24
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Kozina AA, Okuneva EG, Baryshnikova NV, Krasnenko AY, Tsukanov KY, Klimchuk OI, Kondakova OB, Larionova AN, Batysheva TT, Surkova EI, Shatalov PA, Ilinsky VV. A novel MFSD8 mutation in a Russian patient with neuronal ceroid lipofuscinosis type 7: a case report. BMC MEDICAL GENETICS 2018; 19:151. [PMID: 30144815 PMCID: PMC6109285 DOI: 10.1186/s12881-018-0669-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 08/17/2018] [Indexed: 12/30/2022]
Abstract
Background Neuronal ceroid lipofuscinoses (NCLs) are the most common autosomal recessive neurodegenerative disorders in children. Clinical manifestations include progressive cognitive decline, motor impairment, ataxia, visual loss, seizures and early death. To date more than 440 NCL-causing mutations in 13 genes are known. Case presentation We report clinical and genetic characteristics of a 5-year-old girl affected by ceroid lipofuscinosis type 7 (NCL7). She had progressive motor and mental deterioration since the age of 2,5 years. Later she developed progressive vision loss, stereotypies, action myoclonus and epilepsy. By the age of 5 years she stopped walking. Based on symptoms, diagnosis of Rett syndrome was suggested, but no abnormalities were detected in MeCP2. We identified a novel homozygous mutation in MFSD8 gene (c.525 T > A, p.Cys175Ter). To our knowledge, this is the first report of MFSD8 gene mutation in a Russian patient with variant late-infantile NCL. Conclusions Our results enlarge mutational spectrum of ceroid lipofuscinosis type 7 and demonstrate tremendous diagnosis value of exome sequencing for pediatric NCLs. Also we confirmed that NCL should be suspected in patients with Rett-like phenotype at onset and negative MECP2 mutation.
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Affiliation(s)
- Anastasiya Aleksandrovna Kozina
- Institute of Biomedical Chemistry, Pogodinskaya street 10 building 8, 119121, Moscow, Russia.,Genotek Ltd, Nastavnicheskii pereulok 17/1, 105120, Moscow, Russia
| | | | - Natalia Vladimirovna Baryshnikova
- Genotek Ltd, Nastavnicheskii pereulok 17/1, 105120, Moscow, Russia.,Pirogov Russian National Research Medical University, Ostrovitianova street 1, 117997, Moscow, Russia
| | - Anna Yurievna Krasnenko
- Genotek Ltd, Nastavnicheskii pereulok 17/1, 105120, Moscow, Russia.,Pirogov Russian National Research Medical University, Ostrovitianova street 1, 117997, Moscow, Russia
| | | | | | - Olga Borisovna Kondakova
- Scientific and Practical Centre of Pediatric psychoneurology of Moscow Healthcare Department, Michurinsky prospect, 74, 119602, Moscow, Russia
| | - Anna Nikolaevna Larionova
- Scientific and Practical Centre of Pediatric psychoneurology of Moscow Healthcare Department, Michurinsky prospect, 74, 119602, Moscow, Russia
| | - Tatyana Timofeevna Batysheva
- Scientific and Practical Centre of Pediatric psychoneurology of Moscow Healthcare Department, Michurinsky prospect, 74, 119602, Moscow, Russia
| | | | - Peter Alekseevich Shatalov
- Genotek Ltd, Nastavnicheskii pereulok 17/1, 105120, Moscow, Russia.,Veltischev Research and Clinical Institute for Pediatrics of the Pirogov Russian National Research Medical University, Taldomskaya str 2, 125412, Moscow, Russia
| | - Valery Vladimirovich Ilinsky
- Institute of Biomedical Chemistry, Pogodinskaya street 10 building 8, 119121, Moscow, Russia.,Genotek Ltd, Nastavnicheskii pereulok 17/1, 105120, Moscow, Russia.,Pirogov Russian National Research Medical University, Ostrovitianova street 1, 117997, Moscow, Russia.,Vavilov Institute of General Genetics, Gubkina street 3, 119333, Moscow, Russia
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25
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McBride JL, Neuringer M, Ferguson B, Kohama SG, Tagge IJ, Zweig RC, Renner LM, McGill TJ, Stoddard J, Peterson S, Su W, Sherman LS, Domire JS, Ducore RM, Colgin LM, Lewis AD. Discovery of a CLN7 model of Batten disease in non-human primates. Neurobiol Dis 2018; 119:65-78. [PMID: 30048804 PMCID: PMC6200145 DOI: 10.1016/j.nbd.2018.07.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 06/23/2018] [Accepted: 07/12/2018] [Indexed: 12/13/2022] Open
Abstract
We have identified a natural Japanese macaque model of the childhood neurodegenerative disorder neuronal ceroid lipofuscinosis, commonly known as Batten Disease, caused by a homozygous frameshift mutation in the CLN7 gene (CLN7−/−). Affected macaques display progressive neurological deficits including visual impairment, tremor, incoordination, ataxia and impaired balance. Imaging, functional and pathological studies revealed that CLN7−/− macaques have reduced retinal thickness and retinal function early in disease, followed by profound cerebral and cerebellar atrophy that progresses over a five to six-year disease course. Histological analyses showed an accumulation of cerebral, cerebellar and cardiac storage material as well as degeneration of neurons, white matter fragmentation and reactive gliosis throughout the brain of affected animals. This novel CLN7−/− macaque model recapitulates key behavioral and neuropathological features of human Batten Disease and provides novel insights into the pathophysiology linked to CLN7 mutations. These animals will be invaluable for evaluating promising therapeutic strategies for this devastating disease.
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Affiliation(s)
- Jodi L McBride
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, United States; Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, United States.
| | - Martha Neuringer
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, United States; Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, United States
| | - Betsy Ferguson
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, United States; Division of Genetics, Oregon National Primate Research Center, Beaverton, OR, United States; Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, United States
| | - Steven G Kohama
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, United States
| | - Ian J Tagge
- Advanced Imaging Research Center, Oregon Health and Science University, Portland, OR, United States
| | - Robert C Zweig
- Division of Comparative Medicine, Oregon National Primate Research Center, Beaverton, OR, United States
| | - Laurie M Renner
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, United States
| | - Trevor J McGill
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, United States; Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, United States
| | - Jonathan Stoddard
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, United States
| | - Samuel Peterson
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, United States
| | - Weiping Su
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, United States
| | - Larry S Sherman
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, United States; Department of Cell, Developmental and Cancer Biology, Oregon Health & Science University, Portland, OR, United States
| | - Jacqueline S Domire
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, United States
| | - Rebecca M Ducore
- Division of Comparative Medicine, Oregon National Primate Research Center, Beaverton, OR, United States
| | - Lois M Colgin
- Division of Comparative Medicine, Oregon National Primate Research Center, Beaverton, OR, United States
| | - Anne D Lewis
- Division of Comparative Medicine, Oregon National Primate Research Center, Beaverton, OR, United States
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26
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Danyukova T, Ariunbat K, Thelen M, Brocke-Ahmadinejad N, Mole SE, Storch S. Loss of CLN7 results in depletion of soluble lysosomal proteins and impaired mTOR reactivation. Hum Mol Genet 2018; 27:1711-1722. [PMID: 29514215 PMCID: PMC5932567 DOI: 10.1093/hmg/ddy076] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 02/21/2018] [Accepted: 02/22/2018] [Indexed: 12/15/2022] Open
Abstract
Defects in the MFSD8 gene encoding the lysosomal membrane protein CLN7 lead to CLN7 disease, a neurodegenerative lysosomal storage disorder belonging to the group of neuronal ceroid lipofuscinoses. Here, we have performed a SILAC-based quantitative analysis of the lysosomal proteome using Cln7-deficient mouse embryonic fibroblasts (MEFs) from a Cln7 knockout (ko) mouse model. From 3335 different proteins identified, we detected 56 soluble lysosomal proteins and 29 highly abundant lysosomal membrane proteins. Quantification revealed that the amounts of 12 different soluble lysosomal proteins were significantly reduced in Cln7 ko MEFs compared with wild-type controls. One of the most significantly depleted lysosomal proteins was Cln5 protein that underlies another distinct neuronal ceroid lipofuscinosis disorder. Expression analyses showed that the mRNA expression, biosynthesis, intracellular sorting and proteolytic processing of Cln5 were not affected, whereas the depletion of mature Cln5 protein was due to increased proteolytic degradation by cysteine proteases in Cln7 ko lysosomes. Considering the similar phenotypes of CLN5 and CLN7 patients, our data suggest that depletion of CLN5 may play an important part in the pathogenesis of CLN7 disease. In addition, we found a defect in the ability of Cln7 ko MEFs to adapt to starvation conditions as shown by impaired mammalian target of rapamycin complex 1 reactivation, reduced autolysosome tubulation and increased perinuclear accumulation of autolysosomes compared with controls. In summary, depletion of multiple soluble lysosomal proteins suggest a critical role of CLN7 for lysosomal function, which may contribute to the pathogenesis and progression of CLN7 disease.
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Affiliation(s)
- Tatyana Danyukova
- Section Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Khandsuren Ariunbat
- Section Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Melanie Thelen
- Institute of Biochemistry and Molecular Biology, University of Bonn, 53115 Bonn, Germany
| | | | - Sara E Mole
- MRC Laboratory for Molecular Cell Biology, Department of Genetics, Evolution and Environment & UCL GOSH Institute of Child Health, University College London, London WC1E 6BT, UK
| | - Stephan Storch
- Section Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
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27
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Platt FM. Emptying the stores: lysosomal diseases and therapeutic strategies. Nat Rev Drug Discov 2017; 17:133-150. [PMID: 29147032 DOI: 10.1038/nrd.2017.214] [Citation(s) in RCA: 163] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Lysosomal storage disorders (LSDs) - designated as 'orphan' diseases - are inborn errors of metabolism caused by defects in genes that encode proteins involved in various aspects of lysosomal homeostasis. For many years, LSDs were viewed as unattractive targets for the development of therapies owing to their low prevalence. However, the development and success of the first commercial biologic therapy for an LSD - enzyme replacement therapy for type 1 Gaucher disease - coupled with regulatory incentives rapidly catalysed commercial interest in therapeutically targeting LSDs. Despite ongoing challenges, various therapeutic strategies for LSDs now exist, with many agents approved, undergoing clinical trials or in preclinical development.
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Affiliation(s)
- Frances M Platt
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
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28
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Mohammed A, O'Hare MB, Warley A, Tear G, Tuxworth RI. in vivo localization of the neuronal ceroid lipofuscinosis proteins, CLN3 and CLN7, at endogenous expression levels. Neurobiol Dis 2017; 103:123-132. [PMID: 28365214 PMCID: PMC5441185 DOI: 10.1016/j.nbd.2017.03.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 03/03/2017] [Accepted: 03/27/2017] [Indexed: 12/20/2022] Open
Abstract
The neuronal ceroid lipofuscinoses are a group of recessively inherited, childhood-onset neurodegenerative conditions. Several forms are caused by mutations in genes encoding putative lysosomal membrane proteins. Studies of the cell biology underpinning these disorders are hampered by the poor antigenicity of the membrane proteins, which makes visualization of the endogenous proteins difficult. We have used Drosophila to generate knock-in YFP-fusions for two of the NCL membrane proteins: CLN7 and CLN3. The YFP-fusions are expressed at endogenous levels and the proteins can be visualized live without the need for overexpression. Unexpectedly, both CLN7 and CLN3 have restricted expression in the CNS of Drosophila larva and are predominantly expressed in the glia that form the insect blood-brain-barrier. CLN7 is also expressed in neurons in the developing visual system. Analogous with murine CLN3, Drosophila CLN3 is strongly expressed in the excretory and osmoregulatory Malpighian tubules, but the knock-in also reveals unexpected localization of the protein to the apical domain adjacent to the lumen. In addition, some CLN3 protein in the tubules is localized within mitochondria. Our in vivo imaging of CLN7 and CLN3 suggests new possibilities for function and promotes new ideas about the cell biology of the NCLs.
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Affiliation(s)
- Alamin Mohammed
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Megan B O'Hare
- Department of Developmental Neurobiology, King's College London, London SE1 1UL, UK
| | - Alice Warley
- Centre for Ultrastructural Imaging, King's College London, London, SE1 1UL, UK
| | - Guy Tear
- Department of Developmental Neurobiology, King's College London, London SE1 1UL, UK.
| | - Richard I Tuxworth
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK; Department of Developmental Neurobiology, King's College London, London SE1 1UL, UK.
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29
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Brandenstein L, Schweizer M, Sedlacik J, Fiehler J, Storch S. Lysosomal dysfunction and impaired autophagy in a novel mouse model deficient for the lysosomal membrane protein Cln7. Hum Mol Genet 2016; 25:777-91. [PMID: 26681805 DOI: 10.1093/hmg/ddv615] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 12/14/2015] [Indexed: 12/12/2022] Open
Abstract
CLN7 disease is an autosomal recessive, childhood-onset neurodegenerative lysosomal storage disorder caused by the defective lysosomal membrane protein CLN7. We have disrupted the Cln7/Mfsd8 gene in mice by targeted deletion of exon 2 generating a novel knockout (KO) mouse model for CLN7 disease, which recapitulates key features of human CLN7 disease pathology. Cln7 KO mice showed increased mortality and a neurological phenotype including hind limb clasping and myoclonus. Lysosomal dysfunction in the brain of mutant mice was shown by the storage of autofluorescent lipofuscin-like lipopigments, subunit c of mitochondrial ATP synthase and saposin D and increased expression of lysosomal cathepsins B, D and Z. By immunohistochemical co-stainings, increased cathepsin Z expression restricted to Cln7-deficient microglia and neurons was found. Ultrastructural analyses revealed large storage bodies in Purkinje cells of Cln7 KO mice containing inclusions composed of irregular, curvilinear and rectilinear profiles as well as fingerprint profiles. Generalized astrogliosis and microgliosis in the brain preceded neurodegeneration in the olfactory bulb, cerebral cortex and cerebellum in Cln7 KO mice. Increased levels of LC3-II and the presence of neuronal p62- and ubiquitin-positive protein aggregates suggested that impaired autophagy represents a major pathomechanism in the brain of Cln7 KO mice. The data suggest that loss of the putative lysosomal transporter Cln7 in the brain leads to lysosomal dysfunction, impaired constitutive autophagy and neurodegeneration late in disease.
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Affiliation(s)
| | | | - Jan Sedlacik
- Department of Diagnostics and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, Hamburg 20246, Germany
| | - Jens Fiehler
- Department of Diagnostics and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, Hamburg 20246, Germany
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30
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Cell biology of the NCL proteins: What they do and don't do. Biochim Biophys Acta Mol Basis Dis 2015; 1852:2242-55. [PMID: 25962910 DOI: 10.1016/j.bbadis.2015.04.027] [Citation(s) in RCA: 128] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 04/23/2015] [Accepted: 04/24/2015] [Indexed: 02/06/2023]
Abstract
The fatal, primarily childhood neurodegenerative disorders, neuronal ceroid lipofuscinoses (NCLs), are currently associated with mutations in 13 genes. The protein products of these genes (CLN1 to CLN14) differ in their function and their intracellular localization. NCL-associated proteins have been localized mostly in lysosomes (CLN1, CLN2, CLN3, CLN5, CLN7, CLN10, CLN12 and CLN13) but also in the Endoplasmic Reticulum (CLN6 and CLN8), or in the cytosol associated to vesicular membranes (CLN4 and CLN14). Some of them such as CLN1 (palmitoyl protein thioesterase 1), CLN2 (tripeptidyl-peptidase 1), CLN5, CLN10 (cathepsin D), and CLN13 (cathepsin F), are lysosomal soluble proteins; others like CLN3, CLN7, and CLN12, have been proposed to be lysosomal transmembrane proteins. In this review, we give our views and attempt to summarize the proposed and confirmed functions of each NCL protein and describe and discuss research results published since the last review on NCL proteins. This article is part of a Special Issue entitled: "Current Research on the Neuronal Ceroid Lipofuscinoses (Batten Disease)".
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Tian X, Gala U, Zhang Y, Shang W, Nagarkar Jaiswal S, di Ronza A, Jaiswal M, Yamamoto S, Sandoval H, Duraine L, Sardiello M, Sillitoe RV, Venkatachalam K, Fan H, Bellen HJ, Tong C. A voltage-gated calcium channel regulates lysosomal fusion with endosomes and autophagosomes and is required for neuronal homeostasis. PLoS Biol 2015; 13:e1002103. [PMID: 25811491 PMCID: PMC4374850 DOI: 10.1371/journal.pbio.1002103] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2014] [Accepted: 02/11/2015] [Indexed: 01/03/2023] Open
Abstract
Autophagy helps deliver sequestered intracellular cargo to lysosomes for proteolytic degradation and thereby maintains cellular homeostasis by preventing accumulation of toxic substances in cells. In a forward mosaic screen in Drosophila designed to identify genes required for neuronal function and maintenance, we identified multiple cacophony (cac) mutant alleles. They exhibit an age-dependent accumulation of autophagic vacuoles (AVs) in photoreceptor terminals and eventually a degeneration of the terminals and surrounding glia. cac encodes an α1 subunit of a Drosophila voltage-gated calcium channel (VGCC) that is required for synaptic vesicle fusion with the plasma membrane and neurotransmitter release. Here, we show that cac mutant photoreceptor terminals accumulate AV-lysosomal fusion intermediates, suggesting that Cac is necessary for the fusion of AVs with lysosomes, a poorly defined process. Loss of another subunit of the VGCC, α2δ or straightjacket (stj), causes phenotypes very similar to those caused by the loss of cac, indicating that the VGCC is required for AV-lysosomal fusion. The role of VGCC in AV-lysosomal fusion is evolutionarily conserved, as the loss of the mouse homologues, Cacna1a and Cacna2d2, also leads to autophagic defects in mice. Moreover, we find that CACNA1A is localized to the lysosomes and that loss of lysosomal Cacna1a in cerebellar cultured neurons leads to a failure of lysosomes to fuse with endosomes and autophagosomes. Finally, we show that the lysosomal CACNA1A but not the plasma-membrane resident CACNA1A is required for lysosomal fusion. In summary, we present a model in which the VGCC plays a role in autophagy by regulating the fusion of AVs with lysosomes through its calcium channel activity and hence functions in maintaining neuronal homeostasis. A voltage-gated calcium channel required for neurotransmitter release also regulates the fusion of neuronal lysosomes with endosomes and autophagosomes, thereby helping to maintain cellular homeostasis. Autophagy is a cellular process used by cells to prevent the accumulation of toxic substances. It delivers misfolded proteins and damaged organelles by fusing autophagosomes—organelles formed by a double membrane that surrounds the “debris” to be eliminated—with lysosomes. How this fusion process is regulated during autophagy, however, remains to be established. Here, we analyze this process in flies and mice, and find that loss of different subunits of a specific type of Voltage Gated Calcium Channel (VGCC) leads to defects in lysosomal fusion with autophagosomes in neurons. It was already known that VGCCs control calcium entry at synaptic terminals to promote the fusion of synaptic vesicles with the plasma membrane, and that mutations in the subunits of VGCCs in humans cause neurological diseases. Our data indicate that defects in autophagy and lysosomal fusion are independent of defects in synaptic vesicle fusion and neurotransmitter release, and we show that a specific VGCC is present on lysosomal membranes where it is required for lysosomal fusion with endosomes and autophagosomes. These observations suggest that the fusion events required in autophagy rely on mechanisms similar to those that trigger the fusion of synaptic vesicles with the presynaptic membrane.
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Affiliation(s)
- Xuejun Tian
- Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, China
| | - Upasana Gala
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Yongping Zhang
- Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, China
| | - Weina Shang
- Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, China
| | - Sonal Nagarkar Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Alberto di Ronza
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
| | - Manish Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
| | - Shinya Yamamoto
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
| | - Hector Sandoval
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
| | - Lita Duraine
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
| | - Marco Sardiello
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
| | - Roy V. Sillitoe
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
- Department of Pathology and Immunology, Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
| | - Kartik Venkatachalam
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Integrative Biology and Pharmacology, University of Texas School of Medicine, Houston, Texas, United States of America
| | - Hengyu Fan
- Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, China
| | - Hugo J. Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail: (CT), (HJB)
| | - Chao Tong
- Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, China
- * E-mail: (CT), (HJB)
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Guo J, O'Brien DP, Mhlanga-Mutangadura T, Olby NJ, Taylor JF, Schnabel RD, Katz ML, Johnson GS. A rare homozygous MFSD8 single-base-pair deletion and frameshift in the whole genome sequence of a Chinese Crested dog with neuronal ceroid lipofuscinosis. BMC Vet Res 2015; 10:960. [PMID: 25551667 PMCID: PMC4298050 DOI: 10.1186/s12917-014-0181-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 08/06/2014] [Indexed: 02/02/2023] Open
Abstract
Background The neuronal ceroid lipofuscinoses are heritable lysosomal storage diseases characterized by progressive neurological impairment and the accumulation of autofluorescent storage granules in neurons and other cell types. Various forms of human neuronal ceroid lipofuscinosis have been attributed to mutations in at least 13 different genes. So far, mutations in the canine orthologs of 7 of these genes have been identified in DNA from dogs with neuronal ceroid lipofuscinosis. The identification of new causal mutations could lead to the establishment of canine models to investigate the pathogenesis of the corresponding human neuronal ceroid lipofuscinoses and to evaluate and optimize therapeutic interventions for these fatal human diseases. Case presentation We obtained blood and formalin-fixed paraffin-embedded brain sections from a rescue dog that was reported to be a young adult Chinese Crested. The dog was euthanized at approximately 19 months of age as a consequence of progressive neurological decline that included blindness, anxiety, and cognitive impairment. A diagnosis of neuronal ceroid lipofuscinosis was made based on neurological signs, magnetic resonance imaging of the brain, and fluorescence microscopic and electron microscopic examination of brain sections. We isolated DNA from the blood and used it to generate a whole genome sequence with 33-fold average coverage. Among the 7.2 million potential sequence variants revealed by aligning the sequence reads to the canine genome reference sequence was a homozygous single base pair deletion in the canine ortholog of one of 13 known human NCL genes: MFSD8:c.843delT. MFSD8:c.843delT is predicted to cause a frame shift and premature stop codon resulting in a truncated protein, MFSD8:p.F282Lfs13*, missing its 239 C-terminal amino acids. The MFSD8:c.843delT allele is absent from the whole genome sequences of 101 healthy canids or dogs with other diseases. The genotyping of archived DNA from 1478 Chinese Cresteds did not identify any additional MFSD8:c.843delT homozygotes and found only one heterozygote. Conclusion We conclude that the neurodegenerative disease of the Chinese Crested rescue dog was neuronal ceroid lipofuscinosis and that homozygosity for the MFSD8:c.843delT sequence variant was very likely to be the molecular-genetic cause of the disease. Electronic supplementary material The online version of this article (doi:10.1186/s12917-014-0181-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Juyuan Guo
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA.
| | - Dennis P O'Brien
- Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA.
| | - Tendai Mhlanga-Mutangadura
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA.
| | - Natasha J Olby
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.
| | - Jeremy F Taylor
- Division of Animal Science, College of Agriculture, Food and Natural Resources, University of Missouri, Columbia, MO, USA.
| | - Robert D Schnabel
- Division of Animal Science, College of Agriculture, Food and Natural Resources, University of Missouri, Columbia, MO, USA.
| | - Martin L Katz
- Mason Eye Institute, School of Medicine, University of Missouri, Columbia, MO, USA.
| | - Gary S Johnson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA.
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Roosing S, van den Born LI, Sangermano R, Banfi S, Koenekoop RK, Zonneveld-Vrieling MN, Klaver CCW, van Lith-Verhoeven JJC, Cremers FPM, den Hollander AI, Hoyng CB. Mutations in MFSD8, encoding a lysosomal membrane protein, are associated with nonsyndromic autosomal recessive macular dystrophy. Ophthalmology 2015; 122:170-9. [PMID: 25227500 DOI: 10.1016/j.ophtha.2014.07.040] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 05/21/2014] [Accepted: 07/21/2014] [Indexed: 01/09/2023] Open
Abstract
PURPOSE This study aimed to identify the genetic defects in 2 families with autosomal recessive macular dystrophy with central cone involvement. DESIGN Case series. PARTICIPANTS Two families and a cohort of 244 individuals with various inherited maculopathies and cone disorders. METHODS Genome-wide linkage analysis and exome sequencing were performed in 1 large family with 5 affected individuals. In addition, exome sequencing was performed in the proband of a second family. Subsequent analysis of the identified mutations in 244 patients was performed by Sanger sequencing or restriction enzyme digestion. The medical history of individuals carrying the MFSD8 variants was reviewed and additional ophthalmic examinations were performed, including electroretinography (ERG), multifocal ERG (mfERG), perimetry, optical coherence tomography (OCT), fundus autofluorescence, and fundus photography. MAIN OUTCOME MEASURES MFSD8 variants, age at diagnosis, visual acuity, fundus appearance, color vision defects, visual field, ERG, mfERG, fundus autofluorescence, and OCT findings. RESULTS Compound heterozygous variants in MFSD8, a gene encoding a lysosomal transmembrane protein, were identified in 2 families with macular dystrophy with a normal or subnormal ERG, but reduced mfERG. In both families, a heterozygous missense variant p.Glu336Gln was identified, which was predicted to have a mild effect on the protein. In the first family, a protein-truncating variant (p.Glu381*) was identified on the other allele, and in the second family, a variant (c.1102G>C) was identified that results in a splicing defect leading to skipping of exon 11 (p.Lys333Lysfs*3). The p.Glu336Gln allele was found to be significantly enriched in patients with maculopathies and cone disorders (6/488) compared with ethnically matched controls (35/18 682; P < 0.0001), suggesting that it may act as a genetic modifier. CONCLUSIONS In this study, we identified variants in MFSD8 as a novel cause of nonsyndromic autosomal recessive macular dystrophy with central cone involvement. Affected individuals showed no neurologic features typical for variant late-infantile neuronal ceroid lipofuscinosis (vLINCL), a severe and devastating multisystem lysosomal storage disease previously associated with mutations in MFSD8. We propose a genotype-phenotype model in which a combination of a severe and a mild variant cause nonsyndromic macular dystrophy with central cone involvement, and 2 severe mutations cause vLINCL.
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Affiliation(s)
- Susanne Roosing
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands; Current affiliation: Howard Hughes Medical Institute, The Rockefeller University, Department for Pediatric Brain Diseases, New York, New York
| | | | - Riccardo Sangermano
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Sandro Banfi
- Telethon Institute of Genetics and Medicine, Naples, Italy; Medical Genetics, Department of Biochemistry, Biophysics, and General Pathology, Second University of Naples, Naples, Italy
| | - Robert K Koenekoop
- McGill Ocular Genetics Laboratory, McGill University Health Centre, Montreal, Quebec, Canada
| | | | - Caroline C W Klaver
- Department of Ophthalmology, Erasmus Medical Centre, Rotterdam, The Netherlands; Department of Epidemiology, Erasmus Medical Centre, Rotterdam, The Netherlands
| | | | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Anneke I den Hollander
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands; Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Carel B Hoyng
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
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Patiño LC, Battu R, Ortega-Recalde O, Nallathambi J, Anandula VR, Renukaradhya U, Laissue P. Exome sequencing is an efficient tool for variant late-infantile neuronal ceroid lipofuscinosis molecular diagnosis. PLoS One 2014; 9:e109576. [PMID: 25333361 PMCID: PMC4198115 DOI: 10.1371/journal.pone.0109576] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 09/02/2014] [Indexed: 12/28/2022] Open
Abstract
The neuronal ceroid-lipofuscinoses (NCL) is a group of neurodegenerative disorders characterized by epilepsy, visual failure, progressive mental and motor deterioration, myoclonus, dementia and reduced life expectancy. Classically, NCL-affected individuals have been classified into six categories, which have been mainly defined regarding the clinical onset of symptoms. However, some patients cannot be easily included in a specific group because of significant variation in the age of onset and disease progression. Molecular genetics has emerged in recent years as a useful tool for enhancing NCL subtype classification. Fourteen NCL genetic forms (CLN1 to CLN14) have been described to date. The variant late-infantile form of the disease has been linked to CLN5, CLN6, CLN7 (MFSD8) and CLN8 mutations. Despite advances in the diagnosis of neurodegenerative disorders mutations in these genes may cause similar phenotypes, which rends difficult accurate candidate gene selection for direct sequencing. Three siblings who were affected by variant late-infantile NCL are reported in the present study. We used whole-exome sequencing, direct sequencing and in silico approaches to identify the molecular basis of the disease. We identified the novel c.1219T>C (p.Trp407Arg) and c.1361T>C (p.Met454Thr) MFSD8 pathogenic mutations. Our results highlighted next generation sequencing as a novel and powerful methodological approach for the rapid determination of the molecular diagnosis of NCL. They also provide information regarding the phenotypic and molecular spectrum of CLN7 disease.
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Affiliation(s)
- Liliana Catherine Patiño
- Unidad de Genética, Grupo GENIUROS, Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, Colombia
| | - Rajani Battu
- Department of Vitreoretina, Narayana Nethralaya, Bangalore, India
| | - Oscar Ortega-Recalde
- Unidad de Genética, Grupo GENIUROS, Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, Colombia
| | - Jeyabalan Nallathambi
- GROW Research Laboratory, Narayana Nethralaya, Narayana Health City, Bangalore, India
| | | | | | - Paul Laissue
- Unidad de Genética, Grupo GENIUROS, Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, Colombia
- * E-mail:
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Clinico-pathological manifestations of variant late infantile neuronal ceroid lipofuscinosis (vLINCL) caused by a novel mutation in MFSD8 gene. Eur J Med Genet 2014; 57:607-12. [PMID: 25270050 DOI: 10.1016/j.ejmg.2014.09.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 09/15/2014] [Indexed: 11/21/2022]
Abstract
Neuronal ceroid lipofuscinosis (NCL) refers to a growing heterogeneous group of neurodegenerative disorders characterized by lysosomal accumulation of abnormal autofluorescent material. NCLs are traditionally classified clinically according to their age of onset. Variable late infantile NCL (vLINCL) is the most genetically heterogeneous subtype as it has been shown to be caused by mutations in at least six genes. We report on 5 patients of a consanguineous family who presented in early childhood with intractable seizures, severe cognitive and motor decline, behavioral impairment and progressive retinal degeneration. Disease course was severe; all patients were in a vegetative state by the second decade of life, and eventually die prematurely (except in one case). Ultrastructural studies of brain and rectal mucosa disclosed accumulation of storage material in various patterns including fingerprint, curvilinear, and granular osmiophilic deposits consistent with the diagnosis of NCL. Brain pathologic features from a living patient are first reported here and shed light on disease progression and pathogenesis. Using a combination of whole genome autozygosity mapping and candidate gene direct sequencing, we identified a mutation in MFSD8, c.472G>A (p.Gly158Ser), which was found to segregate with the disease phenotype in the family. This study underscores the importance of a combined clinic-molecular workup in NCLs and other neurodegenerative conditions.
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Grubman A, Pollari E, Duncan C, Caragounis A, Blom T, Volitakis I, Wong A, Cooper J, Crouch PJ, Koistinaho J, Jalanko A, White AR, Kanninen KM. Deregulation of biometal homeostasis: the missing link for neuronal ceroid lipofuscinoses? Metallomics 2014; 6:932-43. [PMID: 24804307 DOI: 10.1039/c4mt00032c] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Neuronal ceroid lipofuscinoses (NCLs), a group of genetically distinct fatal neurodegenerative disorders with no treatment or cure, are clinically characterised by progressive motor and visual decline leading to premature death. While the underlying pathological mechanisms are yet to be precisely determined, the diseases share several common features including inflammation, lysosomal lipofuscin deposits and lipid abnormalities. An important hallmark of most common neurodegenerative disorders including Alzheimer's, Parkinson's and motor neuron diseases is deregulation of biologically active metal homeostasis. Metals such as zinc, copper and iron are critical enzyme cofactors and are important for synaptic transmission in the brain, but can mediate oxidative neurotoxicity when homeostatic regulatory mechanisms fail. We previously demonstrated biometal accumulation and altered biometal transporter expression in 3 animal models of CLN6 NCL disease. In this study we investigated the hypothesis that altered biometal homeostasis may be a feature of NCLs in general using 3 additional animal models of CLN1, CLN3 and CLN5 disease. We demonstrated significant accumulation of the biometals zinc, copper, manganese, iron and cobalt in these mice. Patterns of biometal accumulation in each model preceded significant neurodegeneration, and paralleled the relative severity of disease previously described for each model. Additionally, we observed deregulation of transcripts encoding the anti-oxidant protein, metallothionein (Mt), indicative of disruptions to biometal homeostasis. These results demonstrate that altered biometal homeostasis is a key feature of at least 4 genetically distinct forms of NCL disease.
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Bennett MJ, Rakheja D. The neuronal ceroid-lipofuscinoses. ACTA ACUST UNITED AC 2014; 17:254-9. [PMID: 23798013 DOI: 10.1002/ddrr.1118] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/17/2012] [Indexed: 12/15/2022]
Abstract
The neuronal ceroid-lipofuscinoses (NCL's, Batten disease) represent a group of severe neurodegenerative diseases, which mostly present in childhood. The phenotypes are similar and include visual loss, seizures, loss of motor and cognitive function, and early death. At autopsy, there is massive neuronal loss with characteristic storage in remaining neurons. Neurons appear to die because of increased rates of apoptosis and altered autophagy. Ten genes have been identified so far that result in an NCL (CLN1-10). The most common forms are CLN1, CLN2, and CLN3, which were previously known as Infantile, Late-Infantile, and Juvenile NCL's, respectively. CLN1 and CLN2 result from mutations in soluble lysosomal enzymes palmitoyl-protein thioesterase (PPT) and tripeptidyl peptidase 1 (TPP1), which can be measured in white blood cells for clinical diagnosis. Molecular diagnostic testing is routinely available for CLN1, CLN2, and CLN3. Sequencing of other NCL genes may be required to establish a diagnosis when the common forms are ruled out. The pathogenesis of NCL neuronal loss resulting from loss of function of any of the NCL gene products remains unknown and no treatment options are presently available.
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Affiliation(s)
- Michael J Bennett
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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Damme M, Brandenstein L, Fehr S, Jankowiak W, Bartsch U, Schweizer M, Hermans-Borgmeyer I, Storch S. Gene disruption of Mfsd8 in mice provides the first animal model for CLN7 disease. Neurobiol Dis 2014; 65:12-24. [PMID: 24423645 DOI: 10.1016/j.nbd.2014.01.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 12/20/2013] [Accepted: 01/04/2014] [Indexed: 12/28/2022] Open
Abstract
Mutations in the major facilitator superfamily domain containing 8 (MFSD8) gene coding for the lysosomal CLN7 membrane protein result in CLN7 disease, a lysosomal storage disease of childhood. CLN7 disease belongs to a group of inherited disorders, called neuronal ceroid lipofuscinoses (NCL), which are characterized by the accumulation of autofluorescent ceroid lipopigments, neuroinflammation, photoreceptor- and neurodegeneration. We have disrupted the Mfsd8 gene by insertion of a lacZ gene-trap cassette between exons 1 and 2 in mice and have analyzed the impact of Cln7 depletion on neuronal and visceral tissues. Analysis of lacZ reporter gene activity in heterozygous Mfsd8((wt/tm1a)) mice showed strong Mfsd8 mRNA expression in the cerebral cortex, in the hippocampus and in the kidney. Homozygous Mfsd8((tm1a/tm1a)) mice were viable and fertile and resembled biochemically the NCL-phenotype of human CLN7 patients including the accumulation of autofluorescent material in the brain and peripheral tissues and of subunit c of mitochondrial ATP synthase in the cerebellum and nuclei of distinct brain regions, and the degeneration of photoreceptor cells in the retina. Lysosomal storage was found in large neurons of the medulla, the hippocampus and in Purkinje cells of the cerebellum in mutant mice. The ultrastructure of the storage material revealed dense lamellar bodies with irregular forms within cerebellar and hippocampal neurons. In the brain loss of Cln7 was accompanied by mild reactive microgliosis and subtle astrogliosis by 10months of age, respectively. In summary we have generated a mouse model which is partly valuable as some but not all neuropathological features of human CLN7 disease are recapitulated thus representing an animal model to study CLN7-specific disease mechanisms.
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Affiliation(s)
- Markus Damme
- Biochemistry I, Department of Chemistry, Bielefeld University, 33615 Bielefeld, Germany.
| | - Laura Brandenstein
- Department of Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
| | - Susanne Fehr
- Center for Molecular Neurobiology Hamburg, ZMNH, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
| | - Wanda Jankowiak
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
| | - Udo Bartsch
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
| | - Michaela Schweizer
- Center for Molecular Neurobiology Hamburg, ZMNH, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
| | - Irm Hermans-Borgmeyer
- Center for Molecular Neurobiology Hamburg, ZMNH, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
| | - Stephan Storch
- Department of Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
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Kollmann K, Uusi-Rauva K, Scifo E, Tyynelä J, Jalanko A, Braulke T. Cell biology and function of neuronal ceroid lipofuscinosis-related proteins. Biochim Biophys Acta Mol Basis Dis 2013; 1832:1866-81. [PMID: 23402926 DOI: 10.1016/j.bbadis.2013.01.019] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 01/18/2013] [Accepted: 01/23/2013] [Indexed: 01/17/2023]
Abstract
Neuronal ceroid lipofuscinoses (NCL) comprise a group of inherited lysosomal disorders with variable age of onset, characterized by lysosomal accumulation of autofluorescent ceroid lipopigments, neuroinflammation, photoreceptor- and neurodegeneration. Most of the NCL-related genes encode soluble and transmembrane proteins which localize to the endoplasmic reticulum or to the endosomal/lysosomal compartment and directly or indirectly regulate lysosomal function. Recently, exome sequencing led to the identification of four novel gene defects in NCL patients and a new NCL nomenclature currently comprising CLN1 through CLN14. Although the precise function of most of the NCL proteins remains elusive, comprehensive analyses of model organisms, particularly mouse models, provided new insight into pathogenic mechanisms of NCL diseases and roles of mutant NCL proteins in cellular/subcellular protein and lipid homeostasis, as well as their adaptive/compensatorial regulation at the transcriptional level. This review summarizes the current knowledge on the expression, function and regulation of NCL proteins and their impact on lysosomal integrity. This article is part of a Special Issue entitled: The Neuronal Ceroid Lipofuscinoses or Batten Disease.
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Affiliation(s)
- Katrin Kollmann
- Department of Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Heptahelical protein PQLC2 is a lysosomal cationic amino acid exporter underlying the action of cysteamine in cystinosis therapy. Proc Natl Acad Sci U S A 2012; 109:E3434-43. [PMID: 23169667 DOI: 10.1073/pnas.1211198109] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Cystinosin, the lysosomal cystine exporter defective in cystinosis, is the founding member of a family of heptahelical membrane proteins related to bacteriorhodopsin and characterized by a duplicated motif termed the PQ loop. PQ-loop proteins are more frequent in eukaryotes than in prokaryotes; except for cystinosin, their molecular function remains elusive. In this study, we report that three yeast PQ-loop proteins of unknown function, Ypq1, Ypq2, and Ypq3, localize to the vacuolar membrane and are involved in homeostasis of cationic amino acids (CAAs). We also show that PQLC2, a mammalian PQ-loop protein closely related to yeast Ypq proteins, localizes to lysosomes and catalyzes a robust, electrogenic transport that is selective for CAAs and strongly activated at low extracytosolic pH. Heterologous expression of PQLC2 at the yeast vacuole rescues the resistance phenotype of an ypq2 mutant to canavanine, a toxic analog of arginine efficiently transported by PQLC2. Finally, PQLC2 transports a lysine-like mixed disulfide that serves as a chemical intermediate in cysteamine therapy of cystinosis, and PQLC2 gene silencing trapped this intermediate in cystinotic cells. We conclude that PQLC2 and Ypq1-3 proteins are lysosomal/vacuolar exporters of CAAs and suggest that small-molecule transport is a conserved feature of the PQ-loop protein family, in agreement with its distant similarity to SWEET sugar transporters and to the mitochondrial pyruvate carrier. The elucidation of PQLC2 function may help improve cysteamine therapy. It may also clarify the origin of CAA abnormalities in Batten disease.
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Steenhuis P, Froemming J, Reinheckel T, Storch S. Proteolytic cleavage of the disease-related lysosomal membrane glycoprotein CLN7. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1822:1617-28. [PMID: 22668694 DOI: 10.1016/j.bbadis.2012.05.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 05/08/2012] [Accepted: 05/29/2012] [Indexed: 12/15/2022]
Abstract
CLN7 is a polytopic lysosomal membrane glycoprotein of unknown function and is deficient in variant late infantile neuronal ceroid lipofuscinosis. Here we show that full-length CLN7 is proteolytically cleaved twice, once proximal to the used N-glycosylation sites in lumenal loop L9 and once distal to these sites. Cleavage occurs by cysteine proteases in acidic compartments and disruption of lysosomal targeting of CLN7 results in inhibition of proteolytic cleavage. The apparent molecular masses of the CLN7 fragments suggest that both cleavage sites are located within lumenal loop L9. The known disease-causing mutations, p.T294K and p.P412L, localized in lumenal loops L7 and L9, respectively, did not interfere with correct lysosomal targeting of CLN7 but enhanced its proteolytic cleavage in lysosomes. Incubation of cells with selective cysteine protease inhibitors and expression of CLN7 in gene-targeted mouse embryonic fibroblasts revealed that cathepsin L is required for one of the two proteolytic cleavage events. Our findings suggest that CLN7 is inactivated by proteolytic cleavage and that enhanced CLN7 proteolysis caused by missense mutations in selected luminal loops is associated with disease.
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Affiliation(s)
- Pieter Steenhuis
- Department of Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, D-20246 Hamburg, Germany
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Schmiedt ML, Blom T, Blom T, Kopra O, Wong A, von Schantz-Fant C, Ikonen E, Kuronen M, Jauhiainen M, Cooper JD, Jalanko A. Cln5-deficiency in mice leads to microglial activation, defective myelination and changes in lipid metabolism. Neurobiol Dis 2012; 46:19-29. [PMID: 22182690 DOI: 10.1016/j.nbd.2011.12.009] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2011] [Revised: 11/08/2011] [Accepted: 12/04/2011] [Indexed: 11/27/2022] Open
Abstract
CLN5 disease, late infantile variant phenotype neuronal ceroid lipofuscinosis, is a severe neurodegenerative disease caused by mutations in the CLN5 gene, which encodes a lysosomal protein of unknown function. Cln5-deficiency in mice leads to loss of thalamocortical neurons, and glial activation, but the underlying mechanisms are poorly understood. We have now studied the gene expression of Cln5 in the mouse brain and show that it increases gradually with age and differs between neurons and glia, with the highest expression in microglia. In Cln5(-/-) mice, we documented early and significant microglial activation that was already evident at 3 months of age. Loss of Cln5 also leads to defective myelination in vitro and in the developing mouse brain. This was accompanied by early alterations in serum lipid profiles, dysfunctional cellular metabolism and lipid transport in Cln5(-/-) mice. Taken together, these data provide significant new information about events associated with Cln5-deficiency, revealing altered myelination and disturbances in lipid metabolism, together with an early neuroimmune response.
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Affiliation(s)
- Mia-Lisa Schmiedt
- National Institute for Health and Welfare (THL), Public Health Genomics Unit, Helsinki, Finland
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Kousi M, Lehesjoki AE, Mole SE. Update of the mutation spectrum and clinical correlations of over 360 mutations in eight genes that underlie the neuronal ceroid lipofuscinoses. Hum Mutat 2011; 33:42-63. [DOI: 10.1002/humu.21624] [Citation(s) in RCA: 235] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2011] [Accepted: 08/29/2011] [Indexed: 12/17/2022]
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