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Whole-exome sequencing analysis to identify novel potential pathogenetic NPC1 mutations in two Chinese families with Niemann–Pick disease type C. Neurol Sci 2022; 43:3957-3966. [DOI: 10.1007/s10072-022-05896-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 01/13/2022] [Indexed: 10/19/2022]
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2
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Shioi R, Karaki F, Yoshioka H, Noguchi-Yachide T, Ishikawa M, Dodo K, Hashimoto Y, Sodeoka M, Ohgane K. Image-based screen capturing misfolding status of Niemann-Pick type C1 identifies potential candidates for chaperone drugs. PLoS One 2020; 15:e0243746. [PMID: 33315900 PMCID: PMC7735562 DOI: 10.1371/journal.pone.0243746] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 11/26/2020] [Indexed: 02/07/2023] Open
Abstract
Niemann-Pick disease type C is a rare, fatal neurodegenerative disorder characterized by massive intracellular accumulation of cholesterol. In most cases, loss-of-function mutations in the NPC1 gene that encodes lysosomal cholesterol transporter NPC1 are responsible for the disease, and more than half of the mutations are considered to interfere with the biogenesis or folding of the protein. We previously identified a series of oxysterol derivatives and phenanthridine-6-one derivatives as pharmacological chaperones, i.e., small molecules that can rescue folding-defective phenotypes of mutated NPC1, opening up an avenue to develop chaperone therapy for Niemann-Pick disease type C. Here, we present an improved image-based screen for NPC1 chaperones and we describe its application for drug-repurposing screening. We identified some azole antifungals, including itraconazole and posaconazole, and a kinase inhibitor, lapatinib, as probable pharmacological chaperones. A photo-crosslinking study confirmed direct binding of itraconazole to a representative folding-defective mutant protein, NPC1-I1061T. Competitive photo-crosslinking experiments suggested that oxysterol-based chaperones and itraconazole share the same or adjacent binding site(s), and the sensitivity of the crosslinking to P691S mutation in the sterol-sensing domain supports the hypothesis that their binding sites are located near this domain. Although the azoles were less effective in reducing cholesterol accumulation than the oxysterol-derived chaperones or an HDAC inhibitor, LBH-589, our findings should offer new starting points for medicinal chemistry efforts to develop better pharmacological chaperones for NPC1.
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Affiliation(s)
- Ryuta Shioi
- Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Fumika Karaki
- Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Hiromasa Yoshioka
- Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Tomomi Noguchi-Yachide
- Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Minoru Ishikawa
- Graduate School of Life Sciences, Tohoku University, Aoba-ku, Sendai, Japan
| | - Kosuke Dodo
- Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, Japan
| | - Yuichi Hashimoto
- Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Mikiko Sodeoka
- Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, Japan
| | - Kenji Ohgane
- Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, Japan
- * E-mail:
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3
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Seker Yilmaz B, Baruteau J, Rahim AA, Gissen P. Clinical and Molecular Features of Early Infantile Niemann Pick Type C Disease. Int J Mol Sci 2020; 21:E5059. [PMID: 32709131 PMCID: PMC7404201 DOI: 10.3390/ijms21145059] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 07/14/2020] [Accepted: 07/15/2020] [Indexed: 12/22/2022] Open
Abstract
Niemann Pick disease type C (NPC) is a neurovisceral disorder due to mutations in NPC1 or NPC2. This review focuses on poorly characterized clinical and molecular features of early infantile form of NPC (EIF) and identified 89 cases caused by NPC1 (NPC1) and 16 by NPC2 (NPC2) mutations. Extra-neuronal features were common; visceromegaly reported in 80/89 NPC1 and in 15/16 NPC2, prolonged jaundice in 30/89 NPC1 and 7/16 NPC2. Early lung involvement was present in 12/16 NPC2 cases. Median age of neurological onset was 12 (0-24) and 7.5 (0-24) months in NPC1 and NPC2 groups, respectively. Developmental delay and hypotonia were the commonest first detected neurological symptoms reported in 39/89 and 18/89 NPC1, and in 8/16 and 10/16 NPC2, respectively. Additional neurological symptoms included vertical supranuclear gaze palsy, dysarthria, cataplexy, dysphagia, seizures, dystonia, and spasticity. The following mutations in homozygous state conferred EIF: deletion of exon 1+promoter, c.3578_3591 + 9del, c.385delT, p.C63fsX75, IVS21-2delATGC, c. 2740T>A (p.C914S), c.3584G>T (p.G1195V), c.3478-6T>A, c.960_961dup (p.A321Gfs*16) in NPC1 and c.434T>A (p.V145E), c.199T>C (p.S67P), c.133C>T (p.Q45X), c.141C>A (p.C47X) in NPC2. This comprehensive analysis of the EIF type of NPC will benefit clinical patient management, genetic counselling, and assist design of novel therapy trials.
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Affiliation(s)
- Berna Seker Yilmaz
- Genetics and Genomic Medicine Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK; (J.B.); (P.G.)
- Department of Paediatric Metabolic Medicine, Mersin University, Mersin 33110, Turkey
| | - Julien Baruteau
- Genetics and Genomic Medicine Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK; (J.B.); (P.G.)
- National Institute of Health Research Great Ormond Street Biomedical Research Centre, London WC1N 1EH, UK
- Metabolic Medicine Department, Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Ahad A. Rahim
- UCL School of Pharmacy, University College London, London WC1N 1AX, UK;
| | - Paul Gissen
- Genetics and Genomic Medicine Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK; (J.B.); (P.G.)
- National Institute of Health Research Great Ormond Street Biomedical Research Centre, London WC1N 1EH, UK
- Metabolic Medicine Department, Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
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4
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Musalkova D, Majer F, Kuchar L, Luksan O, Asfaw B, Vlaskova H, Storkanova G, Reboun M, Poupetova H, Jahnova H, Hulkova H, Ledvinova J, Dvorakova L, Sikora J, Jirsa M, Vanier MT, Hrebicek M. Transcript, protein, metabolite and cellular studies in skin fibroblasts demonstrate variable pathogenic impacts of NPC1 mutations. Orphanet J Rare Dis 2020; 15:85. [PMID: 32248828 PMCID: PMC7132889 DOI: 10.1186/s13023-020-01360-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 03/17/2020] [Indexed: 12/18/2022] Open
Abstract
Background Niemann-Pick type C (NP-C) is a rare neurovisceral genetic disorder caused by mutations in the NPC1 or the NPC2 gene. NPC1 is a multipass-transmembrane protein essential for egress of cholesterol from late endosomes/lysosomes. To evaluate impacts of NPC1 mutations, we examined fibroblast cultures from 26 NP-C1 patients with clinical phenotypes ranging from infantile to adult neurologic onset forms. The cells were tested with multiple assays including NPC1 mRNA expression levels and allele expression ratios, assessment of NPC1 promoter haplotypes, NPC1 protein levels, cellular cholesterol staining, localization of the mutant NPC1 proteins to lysosomes, and cholesterol/cholesteryl ester ratios. These results were correlated with phenotypes of the individual patients. Results Overall we identified 5 variant promoter haplotypes. Three of them showed reporter activity decreased down to 70% of the control sequence. None of the haplotypes were consistently associated with more severe clinical presentation of NP-C. Levels of transcripts carrying null NPC1 alleles were profoundly lower than levels of the missense variants. Low levels of the mutant NPC1 protein were identified in most samples. The protein localised to lysosomes in cultures expressing medium to normal NPC1 levels. Fibroblasts from patients with severe infantile phenotypes had higher cholesterol levels and higher cholesterol/cholesteryl ester ratios. On the contrary, cell lines from patients with juvenile and adolescent/adult phenotypes showed values comparable to controls. Conclusion No single assay fully correlated with the disease severity. However, low residual levels of NPC1 protein and high cholesterol/cholesteryl ester ratios associated with severe disease. The results suggest not only low NPC1 expression due to non-sense mediated decay or low mutant protein stability, but also dysfunction of the stable mutant NPC1 as contributors to the intracellular lipid transport defect.
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Affiliation(s)
- Dita Musalkova
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Filip Majer
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic.
| | - Ladislav Kuchar
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Ondrej Luksan
- Laboratory of Experimental Hepatology, Institute of Clinical and Experimental Medicine, Prague, Czech Republic
| | - Befekadu Asfaw
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Hana Vlaskova
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Gabriela Storkanova
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Martin Reboun
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Helena Poupetova
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Helena Jahnova
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Helena Hulkova
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Jana Ledvinova
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Lenka Dvorakova
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Jakub Sikora
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic
| | - Milan Jirsa
- Laboratory of Experimental Hepatology, Institute of Clinical and Experimental Medicine, Prague, Czech Republic
| | - Marie T Vanier
- INSERM U820, Lyon, France.,Laboratoire Gillet-Mérieux, Lyon University Hospitals (HCL), Lyon, France
| | - Martin Hrebicek
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, 120 00, Prague 2, Czech Republic.
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5
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Nueva variante asociada a enfermedad de Niemann-Pick tipo C: manifestaciones neurológicas y caracterización bioquímica, molecular y celular. Neurologia 2020; 35:50-52. [DOI: 10.1016/j.nrl.2017.07.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 06/14/2017] [Accepted: 07/02/2017] [Indexed: 01/31/2023] Open
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6
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López de Frutos L, Romero-Imbroda J, Rodríguez-Sureda V, Giraldo P. New variant associated with Niemann-Pick disease type C: neurological manifestations and biochemical, molecular, and cellular characterisation. NEUROLOGÍA (ENGLISH EDITION) 2020. [DOI: 10.1016/j.nrleng.2017.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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7
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Erwood S, Brewer RA, Bily TMI, Maino E, Zhou L, Cohn RD, Ivakine EA. Modeling Niemann-Pick disease type C in a human haploid cell line allows for patient variant characterization and clinical interpretation. Genome Res 2019; 29:2010-2019. [PMID: 31754021 PMCID: PMC6886506 DOI: 10.1101/gr.250720.119] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 11/01/2019] [Indexed: 01/26/2023]
Abstract
The accurate clinical interpretation of human sequence variation is foundational to personalized medicine. This remains a pressing challenge, however, as genome sequencing becomes routine and new functionally undefined variants rapidly accumulate. Here, we describe a platform for the rapid generation, characterization, and interpretation of genomic variants in haploid cells focusing on Niemann–Pick disease type C (NPC) as an example. NPC is a fatal neurodegenerative disorder characterized by a lysosomal accumulation of unesterified cholesterol and glycolipids. In 95% of cases, NPC is caused by mutations in the NPC1 gene, for which more than 200 unique disease-causing variants have been reported to date. Furthermore, the majority of patients with NPC are compound heterozygotes that often carry at least one private mutation, presenting a challenge for the characterization and classification of individual variants. Here, we have developed the first haploid cell model of NPC. This haploid cell model recapitulates the primary biochemical and molecular phenotypes typically found in patient-derived fibroblasts, illustrating its utility in modeling NPC. Additionally, we show the power of CRISPR/Cas9-mediated base editing in quickly and efficiently generating haploid cell models of individual patient variants in NPC. These models provide a platform for understanding the disease mechanisms underlying individual NPC1 variants while allowing for definitive clinical variant interpretation for NPC.
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Affiliation(s)
- Steven Erwood
- Program in Genetics and Genome Biology, The Hospital for Sick Children Research Institute, Toronto, Ontario, M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
| | - Reid A Brewer
- Program in Genetics and Genome Biology, The Hospital for Sick Children Research Institute, Toronto, Ontario, M5G 0A4, Canada
| | - Teija M I Bily
- Program in Genetics and Genome Biology, The Hospital for Sick Children Research Institute, Toronto, Ontario, M5G 0A4, Canada
| | - Eleonora Maino
- Program in Genetics and Genome Biology, The Hospital for Sick Children Research Institute, Toronto, Ontario, M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
| | - Liangchi Zhou
- Program in Genetics and Genome Biology, The Hospital for Sick Children Research Institute, Toronto, Ontario, M5G 0A4, Canada
| | - Ronald D Cohn
- Program in Genetics and Genome Biology, The Hospital for Sick Children Research Institute, Toronto, Ontario, M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.,Department of Pediatrics, University of Toronto and The Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada
| | - Evgueni A Ivakine
- Program in Genetics and Genome Biology, The Hospital for Sick Children Research Institute, Toronto, Ontario, M5G 0A4, Canada
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8
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Determination of the Pathological Features of NPC1 Variants in a Cellular Complementation Test. Int J Mol Sci 2019; 20:ijms20205185. [PMID: 31635081 PMCID: PMC6834306 DOI: 10.3390/ijms20205185] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/09/2019] [Accepted: 10/15/2019] [Indexed: 12/20/2022] Open
Abstract
Niemann-Pick Type C (NP-C) is a rare disorder of lipid metabolism caused by mutations within the NPC1 and NPC2 genes. NP-C is a neurovisceral disease leading to a heterogeneous, multisystemic spectrum of symptoms in those affected. Until now, there is no investigative tool to demonstrate the significance of single variants within the NPC genes. Hence, the aim of the study was to establish a test that allows for an objective assessment of the pathological potential of NPC1 gene variants. Chinese hamster ovary cells defective in the NPC1 gene accumulate cholesterol in lysosomal storage organelles. The cells were transfected with NPC1-GFP plasmid vectors carrying distinct sequence variants. Filipin staining was used to test for complementation of the phenotype. The known variant p.Ile1061Thr showed a significantly impaired cholesterol clearance after 12 and 24 h compared to the wild type. Among the investigated variants, p.Ser954Leu and p.Glu1273Lys showed decelerated cholesterol clearance as well. The remaining variants p.Gln60His, p.Val494Met, and p.Ile787Val showed a cholesterol clearance indistinguishable from wild type. Further, p.Ile1061Thr acquired an enhanced clearance ability upon 25-hydroxycholesterol treatment. We conclude that the variants that caused an abnormal clearance phenotype are highly likely to be of clinical relevance. Moreover, we present a system that can be utilized to screen for new drugs.
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9
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Kumagai T, Terashima H, Uchida H, Fukuda A, Kasahara M, Kosuga M, Okuyama T, Tsunoda T, Inui A, Fujisawa T, Narita A, Eto Y, Kubota M. A case of Niemann-Pick disease type C with neonatal liver failure initially diagnosed as neonatal hemochromatosis. Brain Dev 2019; 41:460-464. [PMID: 30737051 DOI: 10.1016/j.braindev.2019.01.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 12/17/2018] [Accepted: 01/15/2019] [Indexed: 10/27/2022]
Abstract
BACKGROUND Niemann-Pick type C (NPC) is a lysosomal lipid storage disease with mutation of NPC1/NPC2 genes, which transport lipids in the endosome and lysosome, and various neurological symptoms. NPC patients also develop hepatosplenomegaly or liver disorder in the neonatal period, and 10% suffer severe liver failure. Neonatal hemochromatosis (NH) is a liver disorder characterized by hepatic and extrahepatic siderosis. Although the etiology of NH is unclear, recent reports suggest that the gestational alloimmune mechanism is the cause of NH. Herein, we report a Japanese NPC patient initially diagnosed as NH. CASE REPORT A 5-day-old boy was transferred to our hospital with severe cholestatic liver failure. Congenital infections and metabolic screening were negative, and NH was suspected. However intra and extrahepatic siderosis were not found. As his liver deteriorated rapidly, liver transplantation was performed at 19 days old. The explanted liver showed cirrhosis, and strong C5b-9 complex staining of hepatocytes, so NH was diagnosed. From the age of one and a half years, he developed regression, vertical supranuclear gaze palsy and cataplexy. Fibroblast filipin staining was strong, blood oxysterol was high, and there were compound heterozygous mutations in NPC1,p.[(F288L)];[(K1206N)]. The patient was then diagnosed as NPC and started on miglustat. CONCLUSION Neonatal liver failure was initially diagnosed as NH. Later, the patient developed various neurological symptoms characteristic of NPC. Neurological follow-up of children who develop NH is required.
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Affiliation(s)
- Tadayuki Kumagai
- Division of Neurology, National Center for Child Health and Development, Tokyo, Japan; Department of Clinical Laboratory Medicine, National Center for Child Health and Development, Tokyo, Japan.
| | - Hiroshi Terashima
- Division of Neurology, National Center for Child Health and Development, Tokyo, Japan
| | - Hajime Uchida
- Organ Transplantation Center, National Center for Child Health and Development, Tokyo, Japan
| | - Akinari Fukuda
- Organ Transplantation Center, National Center for Child Health and Development, Tokyo, Japan
| | - Mureo Kasahara
- Organ Transplantation Center, National Center for Child Health and Development, Tokyo, Japan
| | - Motomichi Kosuga
- Department of Clinical Laboratory Medicine, National Center for Child Health and Development, Tokyo, Japan
| | - Torayuki Okuyama
- Department of Clinical Laboratory Medicine, National Center for Child Health and Development, Tokyo, Japan
| | - Tomoyuki Tsunoda
- Department of Pediatric Hepatology and Gastroenterology, Saiseikai Yokohamashi Tobu Hospital, Kanagawa, Japan
| | - Ayano Inui
- Department of Pediatric Hepatology and Gastroenterology, Saiseikai Yokohamashi Tobu Hospital, Kanagawa, Japan
| | - Tomoo Fujisawa
- Department of Pediatric Hepatology and Gastroenterology, Saiseikai Yokohamashi Tobu Hospital, Kanagawa, Japan
| | - Aya Narita
- Division of Child Neurology, Institute of Neurological Science, Tottori University, Faculty of Medicine, Yonago, Japan
| | - Yoshikatsu Eto
- Advanced Clinical Research Center, Southern TOHOKU Research Institute for Neuroscience, Fukushima, Japan
| | - Masaya Kubota
- Division of Neurology, National Center for Child Health and Development, Tokyo, Japan
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10
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Shammas H, Kuech EM, Rizk S, Das AM, Naim HY. Different Niemann-Pick C1 Genotypes Generate Protein Phenotypes that Vary in their Intracellular Processing, Trafficking and Localization. Sci Rep 2019; 9:5292. [PMID: 30923329 PMCID: PMC6438969 DOI: 10.1038/s41598-019-41707-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 03/01/2019] [Indexed: 02/08/2023] Open
Abstract
Niemann-Pick Type C (NP-C) is an inherited neurovisceral lysosomal storage disease characterized by a defect in the trafficking of endocytosed cholesterol. In 95% of patients the gene encoding NPC1 is affected. The correlation of the genetic background in NP-C with the clinical phenotype such as, severity and onset of liver dysfunction, ataxia, dystonia and vertical gaze palsy, has not been elucidated at the molecular level. We have designed strategies to investigate the effect of different mutations in the NPC1 gene at the protein and cellular levels. The NPC1 mutants were expressed in mammalian cells and their structural features, maturation pathways and subcellular localization elucidated. Interestingly, three classes of NPC1 mutants could be identified and further characterized. The first group comprised mutants in which the NPC1 protein revealed virtually similar structural features to the wild type species. It was trafficked to the lysosomes and colocalized with the lysosomal protein marker Lamp2. The second class of NPC1 mutants was only partially trafficked to the lysosomes, but predominantly localized to the endoplasmic reticulum (ER). In the third group with the most severe phenotype, NPC1 mutants were entirely retained in the ER, colocalizing with the ER-protein marker calnexin. In conclusion, this study relates NPC1 mutations to the trafficking behavior of the NPC1 mutants along the secretory pathway. The findings are essential for a comprehensive understanding of the pathogenesis of NP-C and propose a mutation-based personalized therapeutical approach.
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Affiliation(s)
- Hadeel Shammas
- Department of Physiological Chemistry, University of Veterinary Medicine Hannover, 30559, Hannover, Germany.,Clinic for Paediatric Kidney-, Liver-, and Metabolic Diseases, Hannover Medical School, 30625, Hannover, Germany
| | - Eva-Maria Kuech
- Department of Physiological Chemistry, University of Veterinary Medicine Hannover, 30559, Hannover, Germany
| | - Sandra Rizk
- Department of Natural Sciences, Lebanese American University, Beirut, 1102-2801, Lebanon
| | - Anibh M Das
- Clinic for Paediatric Kidney-, Liver-, and Metabolic Diseases, Hannover Medical School, 30625, Hannover, Germany
| | - Hassan Y Naim
- Department of Physiological Chemistry, University of Veterinary Medicine Hannover, 30559, Hannover, Germany.
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11
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Lin Y, Cai X, Wang G, Ouyang G, Cao H. Model construction of Niemann-Pick type C disease in zebrafish. Biol Chem 2019; 399:903-910. [PMID: 29897878 DOI: 10.1515/hsz-2018-0118] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 05/14/2018] [Indexed: 11/15/2022]
Abstract
Niemann-Pick type C disease (NPC) is a rare human disease, with limited effective treatment options. Most cases of NPC disease are associated with inactivating mutations of the NPC1 gene. However, cellular and molecular mechanisms responsible for the NPC1 pathogenesis remain poorly defined. This is partly due to the lack of a suitable animal model to monitor the disease progression. In this study, we used CRISPR to construct an NPC1-/- zebrafish model, which faithfully reproduced the cardinal pathological features of this disease. In contrast to the wild type (WT), the deletion of NPC1 alone caused significant hepatosplenomegaly, ataxia, Purkinje cell death, increased lipid storage, infertility and reduced body length and life span. Most of the NPC1-/- zebrafish died within the first month post fertilization, while the remaining specimens developed slower than the WT and died before reaching 8 months of age. Filipin-stained hepatocytes of the NPC1-/- zebrafish were clear, indicating abnormal accumulation of unesterified cholesterol. Lipid profiling showed a significant difference between NPC1-/- and WT zebrafish. An obvious accumulation of seven sphingolipids was detected in livers of NPC1-/- zebrafish. In summary, our results provide a valuable model system that could identify promising therapeutic targets and treatments for the NPC disease.
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Affiliation(s)
- Yusheng Lin
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Donghu South Road 7#, Wuhan 430072, China
| | - Xiaolian Cai
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Donghu South Road 7#, Wuhan 430072, China
| | - Guiping Wang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Donghu South Road 7#, Wuhan 430072, China
| | - Gang Ouyang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Donghu South Road 7#, Wuhan 430072, China
| | - Hong Cao
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Donghu South Road 7#, Wuhan 430072, China
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12
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Polese-Bonatto M, Bock H, Farias ACS, Mergener R, Matte MC, Gil MS, Nepomuceno F, Souza FTS, Gus R, Giugliani R, Saraiva-Pereira ML. Niemann-Pick Disease Type C: Mutation Spectrum and Novel Sequence Variations in the Human NPC1 Gene. Mol Neurobiol 2019; 56:6426-6435. [PMID: 30820861 DOI: 10.1007/s12035-019-1528-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 02/15/2019] [Indexed: 11/28/2022]
Abstract
Niemann-Pick type C (NP-C) is a rare autosomal recessive disorder characterized by storage of unesterified glycolipids and cholesterol in lysosome and/or late endosome due to mutations in either NPC1 or NPC2 gene. This study aims to identify the spectrum of sequence alterations associated to NP-C in individuals with clinical suspicion of this disease. The entire coding region and flanking sequences of both genes associated to NP-C were evaluated in a total of 265 individuals that were referred to our laboratory. Clinical and/or biochemical suspicion of NP-C was confirmed by molecular analysis in 54 subjects. In this cohort, 33 different sequence alterations were identified in NPC1 and one in NPC2. Among those, 5 novel alterations in NPC1 gene were identified as follows: one deletion (p.Lys38_Tyr40del), one frameshift (p.Asn195Lysfs*2), and three missense mutations (p.Cys238Arg, p.Ser365Pro and, p.Val694Met) that are likely to be pathogenic through different approaches, including in silico tools as well as multiple sequence alignment throughout different species. We have also reported main clinical symptoms of patients with novel alterations and distribution of frequent symptoms in the cohort. Findings reported here contribute to the knowledge of mutation spectrum of NP-C, defining frequent mutations as well as novel sequence alterations associated to the disease.
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Affiliation(s)
- Márcia Polese-Bonatto
- Laboratório de Identificação Genética, Centro de Pesquisa Experimental, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil.,Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Hugo Bock
- Laboratório de Identificação Genética, Centro de Pesquisa Experimental, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil.,Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Ana Carolina S Farias
- Laboratório de Identificação Genética, Centro de Pesquisa Experimental, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil
| | - Rafaella Mergener
- Laboratório de Identificação Genética, Centro de Pesquisa Experimental, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil
| | - Maria Cristina Matte
- Laboratório de Identificação Genética, Centro de Pesquisa Experimental, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil
| | - Mirela S Gil
- Laboratório de Identificação Genética, Centro de Pesquisa Experimental, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil
| | - Felipe Nepomuceno
- Programa de Pós-Graduação em Biologia Celular e Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Fernanda T S Souza
- Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil.,Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Rejane Gus
- Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil
| | - Roberto Giugliani
- Laboratório de Identificação Genética, Centro de Pesquisa Experimental, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil.,Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil.,Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.,INAGEMP-Instituto Nacional de Genética Médica Populacional, Porto Alegre, RS, Brazil
| | - Maria Luiza Saraiva-Pereira
- Laboratório de Identificação Genética, Centro de Pesquisa Experimental, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil. .,Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil. .,Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil. .,INAGEMP-Instituto Nacional de Genética Médica Populacional, Porto Alegre, RS, Brazil. .,Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
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13
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Bountouvi E, Papadopoulou A, Vanier MT, Nyktari G, Kanellakis S, Michelakakis H, Dinopoulos A. Novel NPC1 mutations with different segregation in two related Greek patients with Niemann-Pick type C disease: molecular study in the extended pedigree and clinical correlations. BMC MEDICAL GENETICS 2017; 18:51. [PMID: 28472934 PMCID: PMC5415950 DOI: 10.1186/s12881-017-0409-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 04/19/2017] [Indexed: 01/27/2023]
Abstract
BACKGROUND Niemann-Pick type C disease (NPC) is an autosomal recessive, neurovisceral, lysosomal storage disorder with protean and progressive clinical manifestations, resulting from mutations in either of the two genes, NPC1 (~95% of families) and NPC2. Contrary to other populations, published evidence regarding NPC disease in Greece is sparse. METHODS The study population consisted of two Greek NPC patients and their extended pedigree. Patients' clinical, biochemical, molecular profiles and the possible correlations are presented. Genotyping was performed by direct sequencing. Mutations' origin was investigated through selected exonic NPC1 polymorphisms encountered more frequently in a group of 37 Greek patients with clinical suspicion of NPC disease and in a group of 90 healthy Greek individuals, by the use of Haplore software. RESULTS Two novel NPC1 mutations, [IVS23 + 3insT (c.3591 + 3insT) and p. K1057R (c.3170A > C)] were identified and each mutation was associated with a specific haplotype. One of the patients was entered to early treatment with miglustat and has presented no overt neurological impairment after 11.5 years. CONCLUSIONS The splicing mutation IVS23 + 3insT was associated in homozygocity with a severe biochemical and clinical phenotype. A possible founder effect for this mutation was demonstrated in the Greek Island, as well as a different origin for each novel mutation. Longitudinal follow-up may contribute to clarify the possible effect of early miglustat therapy on the patient compound heterozygous for the two novel mutations.
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Affiliation(s)
- Evangelia Bountouvi
- Third Department of Pediatrics, Athens University Medical School, University General Hospital "Attikon", 1 Rimini Str, 12464 -Haidari, Athens, Greece
| | - Anna Papadopoulou
- Third Department of Pediatrics, Athens University Medical School, University General Hospital "Attikon", 1 Rimini Str, 12464 -Haidari, Athens, Greece.
| | - Marie T Vanier
- Laboratoire Gillet-Mérieux, Groupe Hospitalier Est, Hospices Civils de Lyon, Lyon, France
| | - Georgia Nyktari
- Third Department of Pediatrics, Athens University Medical School, University General Hospital "Attikon", 1 Rimini Str, 12464 -Haidari, Athens, Greece
| | - Spyridon Kanellakis
- Department of Nutrition and Dietetics, Harokopio University, Kallithea, Athens, Greece
| | - Helen Michelakakis
- Department of Enzymology and Cellular Function, Institute of Child Health, Athens, Greece
| | - Argyrios Dinopoulos
- Third Department of Pediatrics, Athens University Medical School, University General Hospital "Attikon", 1 Rimini Str, 12464 -Haidari, Athens, Greece
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14
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Phenanthridin-6-one derivatives as the first class of non-steroidal pharmacological chaperones for Niemann-Pick disease type C1 protein. Bioorg Med Chem Lett 2017; 27:2781-2787. [PMID: 28465104 DOI: 10.1016/j.bmcl.2017.04.062] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 04/18/2017] [Accepted: 04/19/2017] [Indexed: 01/20/2023]
Abstract
Niemann-Pick disease type C is a fatal, progressive neurodegenerative disease mostly caused by mutations in Nieamnn-Pick type C1 (NPC1), a late endosomal membrane protein that is essential for intracellular cholesterol transport. The most prevalent mutation, I1061T (Ile to Thr), interferes with the protein folding process. Consequently, mutated but intrinsically functional NPC1 proteins are prematurely degraded via proteasome, leading to loss of NPC1 function. Previously, we reported sterol derivatives as pharmacological chaperones for NPC1, and showed that these derivatives can normalize folding-defective phenotypes of I1061T NPC1 mutant by directly binding to, and stabilizing, the protein. Here, we report a series of compounds containing a phenanthridin-6-one scaffold as the first class of non-steroidal pharmacological chaperones for NPC1. We also examined their structure-activity relationships.
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15
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Patterson MC, Walkley SU. Niemann-Pick disease, type C and Roscoe Brady. Mol Genet Metab 2017; 120:34-37. [PMID: 27923544 DOI: 10.1016/j.ymgme.2016.11.008] [Citation(s) in RCA: 17] [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: 10/12/2016] [Revised: 11/21/2016] [Accepted: 11/21/2016] [Indexed: 10/20/2022]
Abstract
The Niemann-Pick family of diseases was poorly understood until Roscoe Brady and his colleagues began their investigations in the 1960s. Following Brady's discovery of the defect in acid sphingomyelinase in Niemann-Pick disease, types A and B, Peter Pentchev, a senior scientist in the group, launched a series of investigations of an unusual lipid storage disease in a spontaneous mouse model. These led initially to identification of the cholesterol trafficking defect in the mouse, and then in human Niemann-Pick disease, type C (NPC). This discovery formed the basis of the standard diagnostic test for NPC for the next three decades. Subsequently, an international collaboration was established, based at the Brady lab at NIH, which culminated in discovery of the NPC1 gene. Roscoe Brady, Peter Pentchev and their colleagues defined and refined the clinical biochemical and pathological phenotypes of NPC in a series of elegant parallel studies. They also identified abnormal oxysterols in NPC; later work has proved such compounds to be sensitive biomarkers of the disease. The dedication of the Brady lab to NPC, and the discoveries that flowed therefrom, provided critical foundations for the current explosion of progress in this disease.
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Affiliation(s)
- Marc C Patterson
- Department of Neurology, Mayo Clinic Children's Center, RO_MA_16_03ECON, 200 First Street SW, Rochester, MN 55905, United States; Department of Pediatrics and Medical Genetics, Mayo Clinic Children's Center, RO_MA_16_03ECON, 200 First Street SW, Rochester, MN 55905, United States.
| | - Steven U Walkley
- Department of Neuroscience, Rose F. Kennedy Intellectual and Developmental Disabilities Research Center, Albert Einstein College of Medicine, Bronx, New York, NY, United States.
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16
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Wood NW. Cerebellar Ataxias and Related Conditions. Neurology 2016. [DOI: 10.1002/9781118486160.ch17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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17
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Schultz ML, Krus KL, Lieberman AP. Lysosome and endoplasmic reticulum quality control pathways in Niemann-Pick type C disease. Brain Res 2016; 1649:181-188. [PMID: 27026653 DOI: 10.1016/j.brainres.2016.03.035] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/17/2016] [Accepted: 03/24/2016] [Indexed: 12/13/2022]
Abstract
Lysosomal storage diseases result from inherited deficiencies of lysosomal hydrolytic activities or lipid transport. Collectively, these disorders are a common cause of morbidity in the pediatric population and are often associated with severe neurodegeneration. Among this group of diseases is Niemann-Pick type C, an autosomal recessive disorder of lipid trafficking that causes cognitive impairment, ataxia and death, most often in childhood. Here, we review the current knowledge of disease pathogenesis, with particular focus on insights gleaned from genetics and the study of model systems. Critical advances in understanding mechanisms that regulate intracellular cholesterol trafficking have emerged from this work and are highlighted. We review effects of disease-causing mutations on quality control pathways involving the lysosome and endoplasmic reticulum, and discuss how they function to clear the most common mutant protein found in Niemann-Pick type C patients, NPC1-I1061T. Finally, we summarize insights into the mechanisms that degrade misfolded transmembrane proteins in the endoplasmic reticulum and how manipulating these quality control pathways may lead to the identification of novel targets for disease-modifying therapies. This article is part of a Special Issue entitled SI:Autophagy.
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Affiliation(s)
- Mark L Schultz
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, United States
| | - Kelsey L Krus
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, United States
| | - Andrew P Lieberman
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, United States.
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18
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Zhao Y, Ren J, Harlos K, Stuart DI. Structure of glycosylated NPC1 luminal domain C reveals insights into NPC2 and Ebola virus interactions. FEBS Lett 2016; 590:605-12. [PMID: 26846330 PMCID: PMC4819692 DOI: 10.1002/1873-3468.12089] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 01/27/2016] [Accepted: 01/28/2016] [Indexed: 01/14/2023]
Abstract
Niemann‐pick type C1 (NPC1) is an endo/lysosomal membrane protein involved in intracellular cholesterol trafficking, and its luminal domain C is an essential endosomal receptor for Ebola and Marburg viruses. We have determined the crystal structure of glycosylated NPC1 luminal domain C and find all seven possible sites are glycosylated. Mapping the disease mutations onto the glycosylated structure reveals a potential binding face for NPC2. Knowledge‐based docking of NPC1 onto Ebola viral glycoprotein and sequence analysis of filovirus susceptible and refractory species reveals four critical residues, H418, Q421, F502 and F504, some or all of which are likely responsible for the species‐specific susceptibility to the virus infection.
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Affiliation(s)
- Yuguang Zhao
- Division of Structural Biology, University of Oxford, Headington, Oxford, UK
| | - Jingshan Ren
- Division of Structural Biology, University of Oxford, Headington, Oxford, UK
| | - Karl Harlos
- Division of Structural Biology, University of Oxford, Headington, Oxford, UK
| | - David I Stuart
- Division of Structural Biology, University of Oxford, Headington, Oxford, UK.,Diamond Light Source Ltd, Didcot, UK
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19
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Macías-Vidal J, Guerrero-Hernández M, Estanyol JM, Aguado C, Knecht E, Coll MJ, Bachs O. Identification of lysosomal Npc1-binding proteins: Cathepsin D activity is regulated by NPC1. Proteomics 2015; 16:150-8. [PMID: 26507101 DOI: 10.1002/pmic.201500110] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 09/14/2015] [Accepted: 10/14/2015] [Indexed: 11/09/2022]
Abstract
Niemann-Pick type C (NPC) disease is an inherited lysosomal storage disorder, characterized by severe neurodegeneration. It is mostly produced by mutations in the NPC1 gene, encoding for a protein of the late endosomes/lysosomes membrane, involved in cholesterol metabolism. However, the specific role of this protein in NPC disease still remains unknown. We aimed to identify Npc1-binding proteins in order to define new putative NPC1 lysosomal functions. By affinity chromatography using an Npc1 peptide (amino acids 1032-1066 of loop I), as bait, we fished 31 lysosomal proteins subsequently identified by LC-MS/MS. Most of them were involved in proteolysis and lipid catabolism and included the protease cathepsin D. Cathepsin D and NPC1 interaction was validated by immunoprecipitation and the functional relevance of this interaction was studied. We found that fibroblasts from NPC patients with low levels of NPC1 protein have high amounts of procathepsin D but reduced quantities of the mature protein, thus showing a diminished cathepsin D activity. The increase of NPC1 protein levels in NPC cells by treatment with the proteasome inhibitor bortezomib, induced an elevation of cathepsin D activity. All these results suggest a new lysosomal function of NPC1 as a regulator of cathepsin D processing and activity.
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Affiliation(s)
- Judit Macías-Vidal
- Secció d'Errors Congènits del Metabolisme (IBC), Servei de Bioquímica i Genètica Molecular, Hospital Clínic, Barcelona, Spain.,CIBER de Enfermedades Raras (CIBERER), Madrid, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | | | - Josep Maria Estanyol
- Proteomic Unit, Centres Científics i Tecnològics, University of Barcelona, Barcelona, Spain
| | - Carmen Aguado
- CIBER de Enfermedades Raras (CIBERER), Madrid, Spain.,Laboratory of Cellular Biology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Erwin Knecht
- CIBER de Enfermedades Raras (CIBERER), Madrid, Spain.,Laboratory of Cellular Biology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Maria Josep Coll
- Secció d'Errors Congènits del Metabolisme (IBC), Servei de Bioquímica i Genètica Molecular, Hospital Clínic, Barcelona, Spain.,CIBER de Enfermedades Raras (CIBERER), Madrid, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Oriol Bachs
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.,Department of Cell Biology, Immunology and Neurosciences, University of Barcelona, Barcelona, Spain
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20
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Maubert A, Hanon C, Metton JP. [Niemann-Pick type C disease and psychosis: Two siblings]. L'ENCEPHALE 2014; 41:238-43. [PMID: 25238906 DOI: 10.1016/j.encep.2014.08.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 04/22/2014] [Indexed: 10/24/2022]
Abstract
INTRODUCTION Niemann-Pick type C disease (NPC) is a rare, neurovisceral, autosomal recessive disease, with an extremely heterogeneous clinical presentation. The adult form of the disease is usually expressed as a neurological form. Non-specific psychiatric symptoms are often associated with NPC. For some cases, it can also be expressed as an isolated psychiatric disorder form. Since 2009, the launching of a medicine called miglustat has helped to improve the disease evolution. CASE HISTORIES We report two siblings followed-up in the same department of psychiatry and with an atypical psychotic symptomatology. Case 1 is a 27-year-old French male. He was hospitalised several times due to disordered behaviour, psychomotor excitation, mood instability and wandering. He was originally diagnosed with schizophrenia. However, the patient's psychosis proved refractory to treatment. He also exhibited a number of neurological signs (pyramidal signs and abnormal movements of the hands, head and limbs), which were considered related to his antipsychotic medication. Three years later, a full physical, neurological and neuropsychological examination revealed various neurological and visceral symptoms. He was diagnosed with NPC based on a classical biochemical NPC-phenotype following filipin staining in cultured skin fibroblasts. NPC1 gene sequencing revealed that he was a compound heterozygote for the p.S954L and p.N1156S mutations. The patient's psychiatric and neurological symptoms are currently stabilized by miglustat, allowing the patient to cease antipsychotic medication. Case 2 is the elder sister of Case 1. She was hospitalised several times due to acute delirium, hallucinations and suicidal tendencies. She was diagnosed with paranoid schizophrenia at 22 years of age. She has received a variety of typical and atypical antipsychotics. Many of these drugs proved initially effective but the patient's symptoms repeatedly returned. The patient shows persistent and worsening gait disorder and abnormal arm movements. A follow-up neurological examination at age 29 did not detect any ataxia, cataplexy or vertical supra-nuclear gaze palsy. Direct NPC1 gene sequencing detected a mutant NPC1 allele held in common with her brother, but full sequencing of both the NPC1 and NPC2 genes and multiplex ligation-dependent probe amplification (MLPA) did not detect any other pathogenic mutation or other anomalies. DISCUSSION Because NPC is an autosomal recessive condition, heterozygous individuals carrying only one causal gene mutation are usually asymptomatic. Thus, while the accepted wisdom would suggest that patient 2 is not affected by the disease, it is interesting to consider why she has developed neurological and psychiatric disorders like her brother. Several hypotheses are discussed: mental expression in heterozygous genetic factor predisposing to schizophrenia, comorbidity or fortuitous association. It is not currently known whether a patient with a single NPC gene mutation can express NPC in full, partially, or perhaps just to a minimal degree. This case of a patient with a heterozygous "carrier" NPC genotype and neuropsychiatric disorders suggestive of the disease raises the possibility that symptomatic heterozygous NPC patients may exist. On the other hand, if the heterozygous genotype of patient 2 does not give rise to symptomatic disease, it is pertinent to question whether it could be a predisposing factor for the development of psychiatric pathologies. There are currently no published data on the occurrence of heterozygous NPC1 or NPC2 mutations among patients with atypical psychiatric presentations combined with neurological symptoms. Conversely, there are no published data demonstrating an increased frequency of psychiatric disorders in families affected by NPC. Finally, in view of the history of psychiatric disorders in this family, it is possible that psychosis simply occurred concomitantly with symptomatic NPC in patient 1 by chance, and that schizophrenia occurred simultaneously with an asymptomatic NPC carrier genotype in patient 2. To investigate this further, NPC patients' carrier family members (parents and siblings) should be fully screened for signs suggestive of the disease.
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Affiliation(s)
- A Maubert
- EPS Erasme, 143, avenue Armand-Guillebaud, BP 50085, 92161 Antony cedex, France.
| | - C Hanon
- EPS Erasme, 143, avenue Armand-Guillebaud, BP 50085, 92161 Antony cedex, France
| | - J P Metton
- EPS Erasme, 143, avenue Armand-Guillebaud, BP 50085, 92161 Antony cedex, France
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Macías-Vidal J, Girós M, Guerrero M, Gascón P, Serratosa J, Bachs O, Coll MJ. The proteasome inhibitor bortezomib reduced cholesterol accumulation in fibroblasts from Niemann-Pick type C patients carrying missense mutations. FEBS J 2014; 281:4450-66. [PMID: 25131710 DOI: 10.1111/febs.12954] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 07/24/2014] [Accepted: 07/29/2014] [Indexed: 12/01/2022]
Abstract
Niemann-Pick disease type C (NPC) is a lipid storage disorder mainly caused by mutations in the NPC1 gene. Approximately 60% of these mutations are missense changes that may induce reduced NPC1 protein levels by increased degradation via ubiquitin-proteasome. This is the case for the most prevalent worldwide mutation, p.Ile1061Thr, as well as for other three missense changes. In the present study, we analyzed the NPC1 levels in fibroblasts from eighteen NPC patients presenting missense mutations. We found that fourteen of these cells lines showed decreased levels of NPC1. Six of these cell lines were homozygous, whereas the other eight were associated with a frame shifting mutation. We focused our attention in the NPC homozygous samples and demonstrated that, in most of the cases, NPC1 reduction was a consequence of a decrease of its half-life. NPC cells were treated not only with the proteasome inhibitors carbobenzoxy-l-leucyl-l-leucyl-l-leucinal or N-acetyl-leucyl-leucyl-norleucinal, both widely used as a research tools, but also with bortezomib, the first proteasome inhibitor to reach clinical applications, although it has never been used in NPC disease. We observed that, after treatment, the mutant NPC1 protein levels were partially recovered in most of the cell lines. Importantly, these mutant proteins partially recovered their activity and substantially reduced free cholesterol levels. These results suggest that by enhancing the NPC1 protein stability with the use of proteasome inhibitors, their functionality might be recovered and this might represent a therapeutical approach for future treatments of NPC disease resulting from specific missense mutations.
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Affiliation(s)
- Judit Macías-Vidal
- Secció d'Errors Congènits del Metabolisme (IBC), Servei de Bioquímica i Genètica Molecular, Hospital Clínic, Barcelona, Spain; CIBER de Enfermedades Raras (CIBERER), Barcelona, Spain; IDIBAPS, Barcelona, Spain
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22
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Computational screening of disease associated mutations on NPC1 gene and its structural consequence in Niemann-Pick type-C1. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s11515-014-1314-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Ohgane K, Karaki F, Noguchi-Yachide T, Dodo K, Hashimoto Y. Structure–activity relationships of oxysterol-derived pharmacological chaperones for Niemann–Pick type C1 protein. Bioorg Med Chem Lett 2014; 24:3480-5. [DOI: 10.1016/j.bmcl.2014.05.064] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 05/15/2014] [Accepted: 05/17/2014] [Indexed: 11/30/2022]
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Nakasone N, Nakamura YS, Higaki K, Oumi N, Ohno K, Ninomiya H. Endoplasmic reticulum-associated degradation of Niemann-Pick C1: evidence for the role of heat shock proteins and identification of lysine residues that accept ubiquitin. J Biol Chem 2014; 289:19714-25. [PMID: 24891511 DOI: 10.1074/jbc.m114.549915] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Most cases with Niemann-Pick disease type C carry mutations in NPC1. Some of the mutations, including the most frequent I1061T, give rise to unstable proteins selected for endoplasmic reticulum-associated degradation. The purpose of the current study was to shed mechanistic insights into the degradation process. A proteasome inhibitor MG132 prolonged the life span of the wild-type NPC1 expressed in COS cells. The expressed protein associated with multiple chaperones including heat shock protein 90 (Hsp90), Hsp70, heat shock cognate protein 70 (Hsc70), and calnexin. Accordingly, expression of an E3 ligase CHIP (carboxyl terminus of Hsp70-interacting protein) enhanced MG132-induced accumulation of ubiquitylated NPC1. Co-expression and RNAi knockdown experiments in HEK cells indicated that Hsp70/Hsp90 stabilized NPC1, whereas Hsc70 destabilized it. In human fibroblasts carrying the I1061T mutation, adenovirus-mediated expression of Hsp70 or treatment with an HSP-inducer geranylgeranylacetone (GGA) increased the level of the mutant protein. In GGA-treated cells, the rescued protein was localized in the late endosome and ameliorated cholesterol accumulation. MALDI-TOF mass spectrometry revealed three lysine residues at amino acids 318, 792, and 1180 as potential ubiquitin-conjugation sites. Substitutions of the three residues with alanine yielded a mutant protein with a steady-state level more than three times higher than that of the wild-type. Introduction of the same substitutions to the I1061T mutant resulted in an increase in its protein level and functional restoration. These findings indicated the role of HSPs in quality control of NPC1 and revealed the role of three lysine residues as ubiquitin-conjugation sites.
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Affiliation(s)
| | - Yuko S Nakamura
- Applied Biotechnology, Tottori Institute of Industrial Technology, Yonago 684-0041
| | - Katsumi Higaki
- the Division of Functional Genomics, Research Center for Bioscience and Technology, Tottori University, Yonago 683-8503, and
| | - Nao Oumi
- the Tottori University Hospital Cancer Center, Yonago 683-8504, Japan
| | - Kousaku Ohno
- Child Neurology, Tottori University Faculty of Medicine, Yonago 683-8503
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Discovery of Oxysterol-Derived Pharmacological Chaperones for NPC1: Implication for the Existence of Second Sterol-Binding Site. ACTA ACUST UNITED AC 2013; 20:391-402. [DOI: 10.1016/j.chembiol.2013.02.009] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 01/12/2013] [Accepted: 02/07/2013] [Indexed: 11/24/2022]
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Yamashita S. A case of a girl with poor school achievement, ataxia and neurological deterioration. Neuropathology 2011; 32:105-9. [PMID: 21615521 DOI: 10.1111/j.1440-1789.2011.01230.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sumimasa Yamashita
- Division of Child Neurology, Kanagawa Children’s Medical Center, Yokohama, Japan.
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Devlin C, Pipalia NH, Liao X, Schuchman EH, Maxfield FR, Tabas I. Improvement in lipid and protein trafficking in Niemann-Pick C1 cells by correction of a secondary enzyme defect. Traffic 2010; 11:601-15. [PMID: 20412078 DOI: 10.1111/j.1600-0854.2010.01046.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Different primary lysosomal trafficking defects lead to common alterations in lipid trafficking, suggesting cooperative interactions among lysosomal lipids. However, cellular analysis of the functional consequences of this phenomenon is lacking. As a test case, we studied cells with defective Niemann-Pick C1 (NPC1) protein, a cholesterol trafficking protein whose defect gives rise to lysosomal accumulation of cholesterol and other lipids, leading to NPC disease. NPC1 cells also develop a secondary defect in acid sphingomyelinase (SMase) activity despite a normal acid SMase gene (SMPD1). When acid SMase activity was restored to normal levels in NPC1-deficient CHO cells through SMPD1 transfection, there was a dramatic reduction in lysosomal cholesterol. Two other defects, excess lysosomal bis-(monoacylglycerol) phosphate (BMP) and defective transferrin receptor (TfR) recycling, were also markedly improved. To test its relevance in human cells, the acid SMase activity defect in fibroblasts from NPC1 patients was corrected by SMPD1 transfection or acid SMase enzyme replacement. Both treatments resulted in a dramatic reduction in lysosomal cholesterol. These data show that correcting one aspect of a complex lysosomal lipid storage disease can reduce the cellular consequences even if the primary genetic defect is not corrected.
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Affiliation(s)
- Cecilia Devlin
- Department of Medicine, Columbia University, New York, NY 10032, USA
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Garver WS, Jelinek D, Meaney FJ, Flynn J, Pettit KM, Shepherd G, Heidenreich RA, Vockley CMW, Castro G, Francis GA. The National Niemann-Pick Type C1 Disease Database: correlation of lipid profiles, mutations, and biochemical phenotypes. J Lipid Res 2010; 51:406-15. [PMID: 19744920 PMCID: PMC2803243 DOI: 10.1194/jlr.p000331] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Revised: 09/09/2009] [Indexed: 12/17/2022] Open
Abstract
Niemann-Pick type C1 disease (NPC1) is an autosomal recessive lysosomal storage disorder characterized by neonatal jaundice, hepatosplenomegaly, and progressive neurodegeneration. The present study provides the lipid profiles, mutations, and corresponding associations with the biochemical phenotype obtained from NPC1 patients who participated in the National NPC1 Disease Database. Lipid profiles were obtained from 34 patients (39%) in the survey and demonstrated significantly reduced plasma LDL cholesterol (LDL-C) and increased plasma triglycerides in the majority of patients. Reduced plasma HDL cholesterol (HDL-C) was the most consistent lipoprotein abnormality found in male and female NPC1 patients across age groups and occurred independent of changes in plasma triglycerides. A subset of 19 patients for whom the biochemical severity of known NPC1 mutations could be correlated with their lipid profile showed a strong inverse correlation between plasma HDL-C and severity of the biochemical phenotype. Gene mutations were available for 52 patients (59%) in the survey, including 52 different mutations and five novel mutations (Y628C, P887L, I923V, A1151T, and 3741_3744delACTC). Together, these findings provide novel information regarding the plasma lipoprotein changes and mutations in NPC1 disease, and suggest plasma HDL-C represents a potential biomarker of NPC1 disease severity.
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Affiliation(s)
- William S. Garver
- Department of Pediatrics, University of Arizona, 1501 N. Campbell Avenue, Tucson, AZ 85724-5037
| | - David Jelinek
- Department of Pediatrics, University of Arizona, 1501 N. Campbell Avenue, Tucson, AZ 85724-5037
| | - F. John Meaney
- Department of Pediatrics, University of Arizona, 1501 N. Campbell Avenue, Tucson, AZ 85724-5037
| | - James Flynn
- Department of Pediatrics, University of Arizona, 1501 N. Campbell Avenue, Tucson, AZ 85724-5037
| | - Kathleen M. Pettit
- Department of Pediatrics, University of Arizona, 1501 N. Campbell Avenue, Tucson, AZ 85724-5037
| | - Glen Shepherd
- Ara Parseghian Medical Research Foundation, 3530 E. Campo Abierto, Suite 105, Tucson, AZ 85718-3327
| | - Randall A. Heidenreich
- Department of Pediatrics, University of New Mexico, 1 University of New Mexico, Albuquerque, NM 87131-0001
| | - Cate M. Walsh Vockley
- National Niemann-Pick Disease Foundation and Medical Genetics, Children's Hospital of Pittsburgh, 45th StreetPenn Avenue, Pittsburgh, PA 15201
| | - Graciela Castro
- Department of Medicine, University of British Columbia James Hogg Research Centre, St. Paul's Hospital, 1081 Burrard Street, Vancouver, British Columbia, Canada V6Z 1Y6
| | - Gordon A. Francis
- Department of Medicine, University of British Columbia James Hogg Research Centre, St. Paul's Hospital, 1081 Burrard Street, Vancouver, British Columbia, Canada V6Z 1Y6
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29
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Walterfang M, Fietz M, Abel L, Bowman E, Mocellin R, Velakoulis D. Gender dimorphism in siblings with schizophrenia-like psychosis due to Niemann-Pick disease type C. J Inherit Metab Dis 2009; 32 Suppl 1:S221-6. [PMID: 19609713 DOI: 10.1007/s10545-009-1173-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2009] [Revised: 05/11/2009] [Accepted: 05/19/2009] [Indexed: 10/20/2022]
Abstract
We describe the differential presentation of schizophrenia-like psychosis in two siblings with the 'variant' biochemical presentation of adult Niemann-Pick disease type C. The male sibling presented with psychosis at age 16 years and cognitive and motor disturbance at age 25 years, whereas his elder sister, sharing the same mutation but showing less severe biochemical, neuroimaging and ocular motor parameters, presented with a similar schizophrenia-like illness with associated cognitive and motor disturbance at age 31 years. Their illness onset, course and response to treatment mirrors the sex dimorphism seen in schizophrenia, and is suggestive of an interaction between the neurobiology of their metabolic disorder and sex differences in neurodevelopment.
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Affiliation(s)
- M Walterfang
- Neuropsychiatry Unit, Royal Melbourne Hospital, Royal Melbourne Hospital 3050, Melbourne, Victoria, Australia.
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Niemann-Pick disease type C1 is a sphingosine storage disease that causes deregulation of lysosomal calcium. Nat Med 2008; 14:1247-55. [PMID: 18953351 DOI: 10.1038/nm.1876] [Citation(s) in RCA: 637] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Accepted: 09/05/2008] [Indexed: 11/08/2022]
Abstract
Niemann-Pick type C1 (NPC1) disease is a neurodegenerative lysosomal storage disorder caused by mutations in the acidic compartment (which we define as the late endosome and the lysosome) protein, NPC1. The function of NPC1 is unknown, but when it is dysfunctional, sphingosine, glycosphingolipids, sphingomyelin and cholesterol accumulate. We have found that NPC1-mutant cells have a large reduction in the acidic compartment calcium store compared to wild-type cells. Chelating luminal endocytic calcium in normal cells with high-affinity Rhod-dextran induced an NPC disease cellular phenotype. In a drug-induced NPC disease cellular model, sphingosine storage in the acidic compartment led to calcium depletion in these organelles, which then resulted in cholesterol, sphingomyelin and glycosphingolipid storage in these compartments. Sphingosine storage is therefore an initiating factor in NPC1 disease pathogenesis that causes altered calcium homeostasis, leading to the secondary storage of sphingolipids and cholesterol. This unique calcium phenotype represents a new target for therapeutic intervention, as elevation of cytosolic calcium with curcumin normalized NPC1 disease cellular phenotypes and prolonged survival of the NPC1 mouse.
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Abstract
Niemann-Pick type C disease (NPC) is a sphingolipid-storage disorder that results from inherited deficiencies of intracellular lipid-trafficking proteins, and is characterised by an accumulation of cholesterol and glycosphingolipids in late endosomes and lysosomes. Patients with this disorder develop progressive neurological impairment that often begins in childhood, is ultimately fatal and is currently untreatable. How impaired lipid trafficking leads to neurodegeneration is largely unknown. Here we review NPC clinical features and biochemical defects, and discuss model systems used to study this disorder. Recent studies have established that NPC is associated with an induction of autophagy, a regulated and evolutionarily conserved process by which cytoplasmic proteins are sequestered within autophagosomes and targeted for degradation. This pathway enables recycling of limited or damaged macromolecules to promote cell survival. However, in other instances, robust activation of autophagy leads to cell stress and programmed cell death. We summarise evidence showing that autophagy induction and flux are increased in NPC by signalling through a complex of the class III phosphoinositide 3-kinase and beclin-1. We propose that an imbalance between induction and flux through the autophagic pathway contributes to cell stress and neuronal loss in NPC and related sphingolipid-storage disorders, and discuss potential therapeutic strategies for modulating activity of this pathway.
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Affiliation(s)
- Chris D. Pacheco
- Neuroscience Program, University of Michigan, Ann Arbor, MI 48109
| | - Andrew P. Lieberman
- Neuroscience Program, University of Michigan, Ann Arbor, MI 48109
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109
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32
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Garver WS, Francis GA, Jelinek D, Shepherd G, Flynn J, Castro G, Walsh Vockley C, Coppock DL, Pettit KM, Heidenreich RA, Meaney FJ. The National Niemann–Pick C1 disease database: Report of clinical features and health problems. Am J Med Genet A 2007; 143A:1204-11. [PMID: 17497724 DOI: 10.1002/ajmg.a.31735] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Niemann-Pick type C1 (NPC1) disease is an autosomal recessive disorder characterized clinically by neonatal jaundice, hepatosplenomegaly, vertical gaze palsy, ataxia, dystonia, and progressive neurodegeneration. The present study provides basic clinical and health information from the National Niemann-Pick C1 disease database that was obtained using a clinical questionnaire of 83 questions mailed to families affected by NPC1 disease living in the United States. The study was conducted over a 1-year period, during which time parents/caregivers and physicians completed the clinical questionnaire. Sixty-four percent (87/136) of the questionnaires were returned, with 53% and 47% representing male and female NPC1 patients, respectively. The average age of diagnosis for NPC1 disease was 10.4 years, with one-half of patients being diagnosed before the age of 6.9 years. The average age of death for NPC1 disease was 16.2 years, with one-half of patients dying before the age of 12.5 years. A common clinical symptom reported at birth was neonatal jaundice (52%), followed by enlargement of the spleen (36%) and liver (31%); ascites (19%) and neonatal hypotonia (6%) were much less frequent. With respect to developmental difficulties, the most common findings included clumsiness (87%), learning difficulties (87%), ataxia (83%), dysphagia (80%), and vertical gaze palsy (81%). Together, these findings confirm and extend previous reports investigating the clinical features associated with NPC1 disease.
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Affiliation(s)
- William S Garver
- Department of Pediatrics, Arizona Health Sciences Center, The University of Arizona, Tucson, Arizona 85724-5073, and Children's Hospital of Pittsburgh, PA, USA.
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Suzuki M, Sugimoto Y, Ohsaki Y, Ueno M, Kato S, Kitamura Y, Hosokawa H, Davies JP, Ioannou YA, Vanier MT, Ohno K, Ninomiya H. Endosomal accumulation of Toll-like receptor 4 causes constitutive secretion of cytokines and activation of signal transducers and activators of transcription in Niemann-Pick disease type C (NPC) fibroblasts: a potential basis for glial cell activation in the NPC brain. J Neurosci 2007; 27:1879-91. [PMID: 17314284 PMCID: PMC6673540 DOI: 10.1523/jneurosci.5282-06.2007] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Niemann-Pick disease type C (NPC) is an inherited lipid storage disorder caused by mutations in NPC1 or NPC2 genes. Loss of function of either protein results in the endosomal accumulation of cholesterol and other lipids, progressive neurodegeneration, and robust glial cell activation. Here, we report that cultured human NPC fibroblasts secrete interferon-beta, interleukin-6 (IL-6), and IL-8, and contain increased levels of signal transducers and activators of transcription (STATs). These cells also contained increased levels of Toll-like receptor 4 (TLR4) that accumulated in cholesterol-enriched endosomes/lysosomes, and small interfering RNA knockdown of this receptor reduced cytokine secretion. In the NPC1-/- mouse brain, glial cells expressed TLR4 and IL-6, whereas both glial and neuronal cells expressed STATs. Genetic deletion of TLR4 in NPC1-/- mice reduced IL-6 secretion by cultured fibroblasts but failed to alter STAT levels or glial cell activation in the brain. In contrast, genetic deletion of IL-6 normalized STAT levels and suppressed glial cell activation. These findings indicate that constitutive cytokine secretion leads to activation of STATs in NPC fibroblasts and that this secretion is partly caused by an endosomal accumulation of TLR4. These results also suggest that similar signaling events may underlie glial cell activation in the NPC1-/- mouse brain.
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Affiliation(s)
| | | | | | | | | | - Yukisato Kitamura
- Pathology, Tottori University Faculty of Medicine, Yonago 683-8503, Japan
| | - Hiroshi Hosokawa
- Department of Intelligence Science and Technology, Graduate School of Informatics, Kyoto University, Kyoto 606-8501, Japan
| | - Joanna P. Davies
- Department of Human Genetics, Mount Sinai School of Medicine, New York, New York 10029, and
| | - Yiannis A. Ioannou
- Department of Human Genetics, Mount Sinai School of Medicine, New York, New York 10029, and
| | - Marie T. Vanier
- Institut National de la Santé et de la Recherche Médicale, Unité 499, Université Lyon 1, Faculté de Médecine R. T. H. Laënnec, F-69372 Lyon, France
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Ohsaki Y, Sugimoto Y, Suzuki M, Hosokawa H, Yoshimori T, Davies JP, Ioannou YA, Vanier MT, Ohno K, Ninomiya H. Cholesterol depletion facilitates ubiquitylation of NPC1 and its association with SKD1/Vps4. J Cell Sci 2006; 119:2643-53. [PMID: 16757520 DOI: 10.1242/jcs.02993] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Niemann-Pick disease type C (NPC) is an inherited lipid storage disorder caused by mutations in NPC1 or NPC2. NPC1 is a polytopic glycoprotein that contains a sterol-sensing domain, whereas NPC2 is a soluble protein that contains an MD-2-like lipid-recognition domain. In the current study, we addressed the hypothesis that ubiquitylation of NPC1 might be regulated by cholesterol. We found that depletion of cellular cholesterol facilitated ubiquitylation of NPC1 expressed in COS cells. A loss-of-function mutant, NPC1(P691S), which contains an amino acid substitution in the sterol-sensing domain, failed to respond to cholesterol depletion. Another mutant, NPC1(deltaLLNF), which lacks the endosomal-targeting motif, also failed to respond. SKD1(E235Q), a dominant-negative mutant of SKD1/Vps4 that inhibits disassembly of the endosomal sorting complex required for transport (ESCRT), caused an accumulation of ubiquitylated NPC1. SKD1(E235Q) associated with NPC1 on the endosomal membrane, whereas wild-type SKD1 associated with NPC1 only when cells were depleted of cholesterol. Similarly, in control human skin fibroblasts, cholesterol depletion facilitated ubiquitylation of endogenous NPC1. In patient cells that lack NPC2 function, NPC1 was ubiquitylated regardless of cellular cholesterol levels, suggesting that NPC2 is required to prevent NPC1 ubiquitylation under cholesterol-rich conditions. These results suggest that ubiquitylation of NPC1 and its association with the ESCRT complex are controlled by endosomal cholesterol levels utilizing a mechanism that involves NPC2.
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Affiliation(s)
- Yuki Ohsaki
- Department of Neurobiology, Tottori University Faculty of Medicine, Yonago 683-8503, Japan
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Berger AC, Hanson PK, Wylie Nichols J, Corbett AH. A Yeast Model System for Functional Analysis of the Niemann-Pick Type C Protein 1 Homolog, Ncr1p. Traffic 2005; 6:907-17. [PMID: 16138904 DOI: 10.1111/j.1600-0854.2005.00327.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Niemann-Pick disease type C (NP-C) is a progressive, ultimately fatal, autosomal recessive neurodegenerative disorder. The major biochemical hallmark of the disease is the endocytic accumulation of low-density lipoprotein-derived cholesterol. The majority of NP-C patients have mutations in the Niemann-Pick type C1 gene, NPC1. This study focuses on the Saccharomyces cerevisiae homolog of the human NPC1 protein encoded by the NCR1 gene. Ncr1p localizes to the vacuole, the yeast equivalent to the mammalian endosome-lysosome system. Here, we identify the first phenotype caused by deletion of NCR1 from the yeast genome, resistance to the ether lipid drug, edelfosine. Our results indicate that edelfosine has a cytotoxic, rather than cytostatic, effect on wildtype yeast cells. We exploit the edelfosine resistance phenotype to assess the function of yeast Ncr1 proteins carrying amino acid changes corresponding to human NPC1 patient mutations. We find that one of these amino acid changes severely compromises Ncr1p function as assessed using the edelfosine resistance assay. These findings establish S. cerevisiae as a model system that can be exploited to analyze the molecular consequences of patient mutations in NPC1 and provide the basis for future genetic studies using yeast.
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Affiliation(s)
- Adam C Berger
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
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Fernandez-Valero EM, Ballart A, Iturriaga C, Lluch M, Macias J, Vanier MT, Pineda M, Coll MJ. Identification of 25 new mutations in 40 unrelated Spanish Niemann-Pick type C patients: genotype-phenotype correlations. Clin Genet 2005; 68:245-54. [PMID: 16098014 DOI: 10.1111/j.1399-0004.2005.00490.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
To better characterize Niemann-Pick type C (NPC) in Spain and improve genetic counselling, molecular analyses were carried out in 40 unrelated Spanish patients. The search identified 70/80 alleles (88%) involving 38 different NPC1 mutations, 26 of which are described for the first time. No patient with NPC2 mutations was identified. The novel NPC1 mutations include 14 amino acid substitutions [R372W (c.1114C>T), P434L (c.1301C>T), C479Y (c.1436G>A), K576R (c.1727G>A), V727F (c.2179G>T), M754K (c.2261T>A), S865L (c.2594C>T), A926T (c.2776G>A), D948H (c.2842G>C), V959E (c.2876T>A), T1036K (c.3107C>A), T1066N (c.3197C>A), N1156I (c.3467A>T) and F1224L (c.3672C>G)], four stop codon [W260X (c.780G>A), S425X (c.1274C>A), C645X (c.1935T>A) and R1059X (c.3175C>T)], two donor splice-site mutations [IVS7+1G>A (g.31432G>A) and IVS21+2insG (g.51871insG)], one in-frame mutation [N961_F966delinsS (c.2882del16bpins1bp)] and five frameshift mutations [V299fsX8 (c.895insT), A558fsX11 (c.1673insG), C778fsX10 (c.2334insT), G993fsX3 (c.2973_78delG) and F1221fsX20 (c.3662delT)]. We also identified three novel changes [V562V (c.1686G>A), A580A (c.1740C>G) and A1187A (c.3561G>T)] in three independent NPC patients and five polymorphisms that have been described previously. The combination of these polymorphisms gave rise to the establishment of different haplotypes. Linkage disequilibrium was detected between mutations C177Y and G993fsX3 and specific haplotypes, suggesting a unique origin for these mutations. In contrast, I1061T mutation showed at least two different origins. The most prevalent mutations in Spanish patients were I1061T, Q775P, C177Y and P1007A (10, 7, 7 and 5% of alleles, respectively). Our data in homozygous patients indicate that the Q775P mutation correlates with a severe infantile neurological form and the C177Y mutation with a late infantile clinical phenotype.
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Abstract
Niemann-Pick type C (NPC) is a lysosomal storage disorder, characterized by intracellular accumulation of low-density lipoprotein (LDL)-derived cholesterol and neurodegeneration leading to premature death. The most common form of the disease, NPC1, results from mutations in the NPC1 gene. Thus, the NPC1 protein is the focus of intense investigation to elucidate the function of this protein and its role in the disease pathogenesis. Recent studies have revealed the NPC1 subcellular location, topology and potential functions of the NPC1 protein. In lieu of direct experimental evidence, certain hypotheses about the function of NPC1 can be inferred by analyzing disease-causing mutations, NPC1 protein sequence homology to other related proteins, and the potential tertiary structure similarity between NPC1 and its prokaryotic ancestors, such as the E. coli RND permease AcrB. This review will discuss recent work on the characterization and function of the NPC1 protein and highlight structural features that may be important in assisting in the elucidation of NPC1 function and role in subcellular lipid transport and homeostasis.
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Affiliation(s)
- Catherine Scott
- Department of Human Genetics-Box 1498, Mount Sinai School of Medicine, Fifth Avenue at 100th Street, New York, NY 10029, USA
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Yamamoto T, Feng JH, Higaki K, Taniguchi M, Nanba E, Ninomiya H, Ohno K. Increased NPC1 mRNA in skin fibroblasts from Niemann-Pick disease type C patients. Brain Dev 2004; 26:245-50. [PMID: 15130691 DOI: 10.1016/s0387-7604(03)00162-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2002] [Revised: 05/25/2003] [Accepted: 07/24/2003] [Indexed: 11/29/2022]
Abstract
Niemann-Pick disease type C (NP-C) is an autosomal recessive lipid-storage disease that is characterized by progressive neurodegeneration and hepatosplenomegaly. Since identification of the NPC1 gene in 1997, a total of 120 disease-causing mutations have been reported. In this study, two novel mutations were identified, namely c.2508[-2509]A del (837Fs-838X) in exon 16 and T3194G (V1065G) in exon 21. To explore the impact of NPC1 mutations on transcription of this gene, we analyzed NPC1 mRNA levels in skin fibroblasts derived from NP-C patients. Fibroblasts from patients with missense mutations showed increased levels of NPC1 mRNA while fibroblasts from patients with a specific frameshift mutation showed mRNA levels similar to those of normal control subjects. These results suggest that NPC1 transcription levels are altered in cells with mutations in the NPC1 gene.
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Affiliation(s)
- Toshiyuki Yamamoto
- Division of Medical Genetics, Kanagawa Children's Medical Center, 2-138-4 Mutsukawa, Minami-ku, Yokohama 232-8555, Japan.
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Ohsaki Y, Sugimoto Y, Suzuki M, Kaidoh T, Shimada Y, Ohno-Iwashita Y, Davies JP, Ioannou YA, Ohno K, Ninomiya H. Reduced sensitivity of Niemann-Pick C1-deficient cells to theta-toxin (perfringolysin O): sequestration of toxin to raft-enriched membrane vesicles. Histochem Cell Biol 2004; 121:263-72. [PMID: 15069562 DOI: 10.1007/s00418-004-0643-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/16/2004] [Indexed: 01/04/2023]
Abstract
Theta-toxin (perfringolysin O) binds to cell surface cholesterol and forms oligomeric pores that cause membrane damage. Both in cytotoxicity and cell survival assays, a mutant Chinese hamster ovary cell line NPC1(-) that lacked Niemann-Pick C1 showed reduced sensitivity to theta-toxin, compared with wild-type (wt) cells. BCtheta is a derivative of theta-toxin that retains cholesterol-binding activity but lacks cytotoxicity. Confocal and electron microscopy revealed the presence of multiple vesicles which bound BCtheta, both on the cell surface and in the extracellular space of these cells. BCtheta binding to raft microdomains was verified by its resistance to 1% Triton X-100 at 4 degrees C and recovery of bound BCtheta in floating low-density fractions on sucrose density gradient fractionation. BCtheta-labeled vesicles were abolished when NPC1(-) cells were depleted of lipoproteins and also when treated with a Rho-associated kinase inhibitor Y-27632. In addition, similar vesicles were observed in wt cells treated with progesterone. In parallel with these results, theta-toxin sensitivity of NPC1(-) cells was increased when cells were depleted of lipoproteins or treated with Y-27632, whereas that of wt cells was decreased by progesterone. Our findings suggest that sequestration of toxin to raft-enriched cell surface vesicles may underlie reduced sensitivity of NPC1-deficient cells to theta-toxin.
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Affiliation(s)
- Yuki Ohsaki
- Department of Neurobiology, Tottori University Faculty of Medicine, 683-8503, Yonago, Japan
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40
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Battisti C, Tarugi P, Dotti MT, De Stefano N, Vattimo A, Chierichetti F, Calandra S, Federico A. Adult onset Niemann-Pick type C disease: A clinical, neuroimaging and molecular genetic study. Mov Disord 2004; 18:1405-9. [PMID: 14639697 DOI: 10.1002/mds.10541] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
We report on a patient with adult-onset Niemann-Pick type C (NPC) disease, carrying the mutations P1007 and I1061T in the NPC1 gene, presenting with marked psychiatric changes followed by dystonia and cognitive impairment. Filipin staining, single photon emission computed tomography perfusional, positron emission tomography metabolic, conventional magnetic resonance imaging, and magnetic resonance spectroscopy findings suggested a pathophysiological correlation with phenotype expression. This case expands the clinical and genetic spectrum of the rare adult-onset NPC disease phenotype.
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Affiliation(s)
- Carla Battisti
- Department of Neurological and Behavioural Sciences, University of Siena, Siena, Italy
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41
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Abstract
Niemann-Pick disease type C (NPC) is an autosomal recessive neurovisceral lipid storage with a wide spectrum of clinical phenotypes. At the cellular level, the disorder is characterized by accumulation of unesterified cholesterol and glycolipids in the lysosomal/late endosomal system. Approximatively 95% of patients have mutations in the NPC1 gene (mapped at 18q11) which encodes a large membrane glycoprotein primarily located to late endosomes. The remainder have mutations in the NPC2 gene (mapped at 14q24.3) which encodes a small soluble lysosomal protein with cholesterol-binding properties. The identical biochemical patterns observed in NPC1 and NPC2 mutants suggest that the two proteins function in a coordinate fashion. Identification of mutations revealed a complex picture of molecular heterogeneity, allowing genotype - phenotype correlations for both genes and providing insights into structure - function relationships for the NPC1 protein. Although a whole body of evidence suggests that the NPC1 and NPC2 proteins are involved in the cellular postlysosomal/late endosomal transport of cholesterol, glycolipids and other cargo, their precise functions and relationship remain unclear and are currently the subject of intense investigation. These studies, conducted in various models, should ultimately lead to a better understanding of the pathophysiology of NPC and new therapeutic approaches.
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Affiliation(s)
- M T Vanier
- INSERM Unit 189, Lyon-Sud Medical School, Oullins and Fondation Gillet-Mérieux, Lyon-Sud Hospital, Pierre-Bénite, France.
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Park WD, O'Brien JF, Lundquist PA, Kraft DL, Vockley CW, Karnes PS, Patterson MC, Snow K. Identification of 58 novel mutations in Niemann-Pick disease type C: correlation with biochemical phenotype and importance of PTC1-like domains in NPC1. Hum Mutat 2003; 22:313-25. [PMID: 12955717 DOI: 10.1002/humu.10255] [Citation(s) in RCA: 140] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The two known complementation groups of Niemann-Pick Type C disease, NPC1 and NPC2, result from non-allelic protein defects. Both the NPC1 and NPC2 (HE1) gene products are intimately involved in cholesterol and glycolipid trafficking and/or transport. We describe mutation analysis on samples from 143 unrelated affected NPC patients using conformation sensitive gel electrophoresis and DNA sequencing as the primary mutation screening methods for NPC1 and NPC2, respectively. These methods are robust, sensitive, and do not require any specialized laboratory equipment. Analyses identified two NPC1 mutations for 115 (80.4%) patients, one NPC1 mutation for 10 (7.0%) patients, two NPC2 mutations for five (3.5%) patients, one NPC2 mutation for one (0.7%) patient, and no mutations for 12 (8.4%) patients. Thus, mutations were identified on 251 of 286 (88%) disease alleles, including 121 different mutations (114 in NPC1 and seven in NPC2), 58 of which are previously unreported. The most common NPC1 mutation, I1061T, was detected on 18% of NPC alleles. Other NPC1 mutations were mostly private, missense mutations located throughout the gene with clustering in the cysteine-rich luminal domain. Correlation with biochemical data suggests classification of several mutations as severe and others as moderate or variable. The region between amino acids 1038 and 1253, which shares 35% identity with Patched 1, appears to be a hot spot for mutations. Additionally, a high percentage of mutations were located at amino acids identical to the NPC1 homolog, NPC1L1. Biochemical complementation analysis of cases negative for mutations revealed a high percentage of equivocal results where the complementation group appeared to be non-NPC1 and non-NPC2. This raises the possibilities of an additional NPC complementation group(s) or non-specificity of the biochemical testing for NPC. These caveats must be considered when offering mutation testing as a clinical service.
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Affiliation(s)
- Walter D Park
- Division of Laboratory Genetics, Department of Laboratory Medicine and Pathology, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA
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43
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Tarugi P, Ballarini G, Bembi B, Battisti C, Palmeri S, Panzani F, Di Leo E, Martini C, Federico A, Calandra S. Niemann-Pick type C disease: mutations of NPC1 gene and evidence of abnormal expression of some mutant alleles in fibroblasts. J Lipid Res 2002; 43:1908-19. [PMID: 12401890 DOI: 10.1194/jlr.m200203-jlr200] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We analyzed Niemann-Pick type C disease 1 (NPC1) gene in 12 patients with Niemann-Pick type C disease by sequencing both cDNA obtained from fibroblasts and genomic DNA. All the patients were compound heterozygotes. We found 15 mutations, eight of which previously unreported. The comparison of cDNA and genomic DNA revealed discrepancies in some subjects. In two unrelated patients carrying the same mutations (P474L and nt 2972del2) only one mutant allele (P474L), was expressed in fibroblasts. The mRNA corresponding to the other allele was not detected even in cells incubated with cycloheximide. The promoter variants (-1026T/G and -1186T/C or -238 C/G), found to be in linkage with 2972del2 allele do not explain the lack of expression of this allele, as they were also found in control subjects. In another patient, (N1156S/Q922X) the N1156S allele was expressed in fibroblasts while the expression of the other allele was hardly detectable. In a fourth patient cDNA analysis revealed a point mutation in exon 20 (P1007A) and a 56 nt deletion in exon 22 leading to a frameshift and a premature stop codon. The first mutation was confirmed in genomic DNA; the second turned out to be a T-->G transversion in exon 22, predicted to cause a missense mutation (V1141G). In fact, this transversion generates a donor splice site in exon 22, which causes an abnormal pre-mRNA splicing leading to a partial deletion of this exon. In some NPC patients, therefore, the comparison between cDNA and genomic DNA may reveal an unexpected expression of some mutant alleles of NPC1 gene.
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Affiliation(s)
- Patrizia Tarugi
- Dipartimento di Scienze Biomediche, Università di Modena e Reggio Emilia, Modena, Italy
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Saito Y, Suzuki K, Nanba E, Yamamoto T, Ohno K, Murayama S. Niemann-Pick type C disease: accelerated neurofibrillary tangle formation and amyloid beta deposition associated with apolipoprotein E epsilon 4 homozygosity. Ann Neurol 2002; 52:351-5. [PMID: 12205649 DOI: 10.1002/ana.10266] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Niemann-Pick type C disease is a neurovisceral storage disorder. Neurofibrillary tangles similar to those in Alzheimer's disease have been reported in most juvenile/adult patients without amyloid beta protein (Abeta) deposits. Recently, we found deposits of Abeta in the form of diffuse plaques in three (31- and 32-year-old sisters and a 37-year-old man) of nine Niemann-Pick type C disease patients, who presented with most severe tauopathy and with numerous neurofibrillary tangles. Abeta deposits were not detected in any of the control brains of patients younger than age 42 years. These three patients with Abeta deposit all were homozygotes of apolipoprotein E epsilon 4. Our study suggested that NPC1 gene mutations combined with homozygosity of apolipoprotein E epsilon 4 alleles could manifest neuropathology similar to that of Alzheimer's disease. Investigation of these patients may provide an important clue for understanding the pathogenesis of Alzheimer's disease.
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Affiliation(s)
- Yuko Saito
- Department of Neuropathology, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
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45
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Abstract
Hepatocyte injury and necrosis from many causes may result in pediatric liver disease. Influenced by other cell types in the liver, by its unique vascular arrangements, by lobular zonation, and by contributory effects of sepsis, reactive oxygen species and disordered hepatic architecture, the hepatocyte is prone to injury from exogenous toxins, from inborn errors of metabolism, from hepatotrophic viruses, and from immune mechanisms. Experimental studies on cultured hepatocytes or animal models must be interpreted with caution. Having discussed general concepts, this review describes immune mechanisms of liver injury, as seen in autoimmune hepatitis, hepatitis B and C infection, the anticonvulsant hypersensitivity syndrome, and autoimmune polyendocrinopathy. Of the monogenic disorders causing significant liver injury in childhood, alpha-1 antitrypsin deficiency and Niemann-Pick C disease demonstrate the effect of endoplasmic or endosomal retention of macromolecules. Tyrosinemia illustrates how understanding the biochemical defect leads to understanding cell injury, extrahepatic porphyric effects, oncogenesis, pharmacological intervention, and possible stem cell therapy. Pathogenesis of cirrhosis in galactosemia remains incompletely understood. In hereditary fructose intolerance, phosphate sequestration causes ATP depletion. Recent information about mitochondrial disease, NASH, disorders of glycosylation, Wilson's disease, and the progressive familial intrahepatic cholestases is discussed.
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Affiliation(s)
- M S Tanner
- Institute of Child Health, University of Sheffield Children's Hospital, Western Bank, UK
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46
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Bauer P, Knoblich R, Bauer C, Finckh U, Hufen A, Kropp J, Braun S, Kustermann-Kuhn B, Schmidt D, Harzer K, Rolfs A. NPC1: Complete genomic sequence, mutation analysis, and characterization of haplotypes. Hum Mutat 2002; 19:30-8. [PMID: 11754101 DOI: 10.1002/humu.10016] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Niemann-Pick type C disease (NP-C) is a rare, autosomal recessive lipid storage disorder. At least 96% of all NP-C patients link to NPC1 which encodes for a lysosomally-targeted protein. We describe the complete genomic sequence of 57,052 kb corresponding to the transcribed region of human NPC1 including several exonic and intronic single nucleotide polymorphisms (SNPs). Sequencing of all exons, splice sites, and the promoter region of NPC1 in 12 unrelated Caucasian NP-C patients revealed nine novel and four known most likely disease-causing mutations. Ten unique mutations found only once in 24 disease alleles were observed in patients being compound heterozygous for two different mutations. Two of the three missense mutations identified more than once were observed in a total of four patients homozygous for the respective mutation along with homozygosity for the underlying haplotype. The patients were offspring of most likely nonconsanguineous couples. Based upon genotyping exonic SNPs c.2572A>G (I858V; g.45020A>G) and c.2793C>T (N931N; g.45686C>T) and segregation analysis we characterized the haplotype of all 24 NPC1 alleles and of 138 alleles of healthy Caucasian control subjects. All four permutations between the two SNPs were identified in the control alleles: 2572A-2793C (50%), 2572G-2793T (41%), 2572G-2793C (5%), and 2572A-2793T (4%). These data are suggestive for an ancestral intragenic recombination within a genomic fragment of <666 bp. While 17 of 24 NP-C alleles (71%) shared haplotype 2572G-2793T, this haplotype accounted for only 41% in the controls (p=0.007; 2-sided Fisher exact test) suggesting the possibility of an influence of the haplotypic background on expression of missense mutations in NPC1.
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Affiliation(s)
- Peter Bauer
- Universität Rostock, Klinik für Neurologie und Poliklinik, Neurobiologisches Labor, Rostock, Germany
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47
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Millat G, Chikh K, Naureckiene S, Sleat DE, Fensom AH, Higaki K, Elleder M, Lobel P, Vanier MT. Niemann-Pick disease type C: spectrum of HE1 mutations and genotype/phenotype correlations in the NPC2 group. Am J Hum Genet 2001; 69:1013-21. [PMID: 11567215 PMCID: PMC1274348 DOI: 10.1086/324068] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2001] [Accepted: 08/27/2001] [Indexed: 11/04/2022] Open
Abstract
In Niemann-Pick disease type C (NPC), a genetic heterogeneity with two complementation groups--NPC1, comprising > or =95% of the families, and NPC2--has been demonstrated. Mutations in the NPC1 gene have now been well characterized. HE1 was recently identified as the gene underlying the very rare NPC2. Here we report the first comprehensive study of eight unrelated families with NPC2, originating from France, Algeria, Italy, Germany, the Czech Republic, and Turkey. These cases represent essentially all patients with NPC2 who have been reported in the literature, as well as those known to us. All 16 mutant alleles were identified, but only five different mutations, all with a severe impact on the protein, were found; these five mutations were as follows: two nonsense mutations (E20X and E118X), a 1-bp deletion (27delG), a splice mutation (IVS2+5G-->A), and a missense mutation (S67P) resulting in reduced amounts of abnormal HE1 protein. E20X, with an overall allele frequency of 56%, was established as the common mutant allele. Prenatal diagnosis was achieved by mutation analysis of an uncultured chorionic-villus sample. All mutations except 27delG were observed in a homozygous state, allowing genotype/phenotype correlations. In seven families (with E20X, E118X, S67P, and E20X/27delG mutations), patients suffered a severe and rapid disease course, with age at death being 6 mo-4 years. A remarkable feature was the pronounced lung involvement, leading, in six patients, to early death caused by respiratory failure. Two patients also developed a severe neurological disease with onset during infancy. Conversely, the splice mutation corresponded to a very different clinical presentation, with juvenile onset of neurological symptoms and prolonged survival. This mutation generated multiple transcripts, including a minute proportion of normally spliced RNA, which may explain the milder phenotype.
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Affiliation(s)
- Gilles Millat
- INSERM Unit 189, Lyon-Sud Medical School, Oullins, France; Fondation Gillet-Mérieux, Lyon-Sud Hospital, Pierre-Bénite, France; Center for Advanced Biotechnology and Medicine, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway; Division of Medical and Molecular Genetics, the Guy’s, King’s and St Thomas' School of Medicine, Guy’s Hospital, London; Department of Neurobiology, School of Life Science, Tottori University Faculty of Medicine, Yonago, Japan; and Institute of Inherited Metabolic Disorders, 1st Faculty of Medicine, Charles University, Prague
| | - Karim Chikh
- INSERM Unit 189, Lyon-Sud Medical School, Oullins, France; Fondation Gillet-Mérieux, Lyon-Sud Hospital, Pierre-Bénite, France; Center for Advanced Biotechnology and Medicine, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway; Division of Medical and Molecular Genetics, the Guy’s, King’s and St Thomas' School of Medicine, Guy’s Hospital, London; Department of Neurobiology, School of Life Science, Tottori University Faculty of Medicine, Yonago, Japan; and Institute of Inherited Metabolic Disorders, 1st Faculty of Medicine, Charles University, Prague
| | - Saule Naureckiene
- INSERM Unit 189, Lyon-Sud Medical School, Oullins, France; Fondation Gillet-Mérieux, Lyon-Sud Hospital, Pierre-Bénite, France; Center for Advanced Biotechnology and Medicine, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway; Division of Medical and Molecular Genetics, the Guy’s, King’s and St Thomas' School of Medicine, Guy’s Hospital, London; Department of Neurobiology, School of Life Science, Tottori University Faculty of Medicine, Yonago, Japan; and Institute of Inherited Metabolic Disorders, 1st Faculty of Medicine, Charles University, Prague
| | - David E. Sleat
- INSERM Unit 189, Lyon-Sud Medical School, Oullins, France; Fondation Gillet-Mérieux, Lyon-Sud Hospital, Pierre-Bénite, France; Center for Advanced Biotechnology and Medicine, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway; Division of Medical and Molecular Genetics, the Guy’s, King’s and St Thomas' School of Medicine, Guy’s Hospital, London; Department of Neurobiology, School of Life Science, Tottori University Faculty of Medicine, Yonago, Japan; and Institute of Inherited Metabolic Disorders, 1st Faculty of Medicine, Charles University, Prague
| | - Anthony H. Fensom
- INSERM Unit 189, Lyon-Sud Medical School, Oullins, France; Fondation Gillet-Mérieux, Lyon-Sud Hospital, Pierre-Bénite, France; Center for Advanced Biotechnology and Medicine, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway; Division of Medical and Molecular Genetics, the Guy’s, King’s and St Thomas' School of Medicine, Guy’s Hospital, London; Department of Neurobiology, School of Life Science, Tottori University Faculty of Medicine, Yonago, Japan; and Institute of Inherited Metabolic Disorders, 1st Faculty of Medicine, Charles University, Prague
| | - Katsumi Higaki
- INSERM Unit 189, Lyon-Sud Medical School, Oullins, France; Fondation Gillet-Mérieux, Lyon-Sud Hospital, Pierre-Bénite, France; Center for Advanced Biotechnology and Medicine, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway; Division of Medical and Molecular Genetics, the Guy’s, King’s and St Thomas' School of Medicine, Guy’s Hospital, London; Department of Neurobiology, School of Life Science, Tottori University Faculty of Medicine, Yonago, Japan; and Institute of Inherited Metabolic Disorders, 1st Faculty of Medicine, Charles University, Prague
| | - Milan Elleder
- INSERM Unit 189, Lyon-Sud Medical School, Oullins, France; Fondation Gillet-Mérieux, Lyon-Sud Hospital, Pierre-Bénite, France; Center for Advanced Biotechnology and Medicine, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway; Division of Medical and Molecular Genetics, the Guy’s, King’s and St Thomas' School of Medicine, Guy’s Hospital, London; Department of Neurobiology, School of Life Science, Tottori University Faculty of Medicine, Yonago, Japan; and Institute of Inherited Metabolic Disorders, 1st Faculty of Medicine, Charles University, Prague
| | - Peter Lobel
- INSERM Unit 189, Lyon-Sud Medical School, Oullins, France; Fondation Gillet-Mérieux, Lyon-Sud Hospital, Pierre-Bénite, France; Center for Advanced Biotechnology and Medicine, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway; Division of Medical and Molecular Genetics, the Guy’s, King’s and St Thomas' School of Medicine, Guy’s Hospital, London; Department of Neurobiology, School of Life Science, Tottori University Faculty of Medicine, Yonago, Japan; and Institute of Inherited Metabolic Disorders, 1st Faculty of Medicine, Charles University, Prague
| | - Marie T. Vanier
- INSERM Unit 189, Lyon-Sud Medical School, Oullins, France; Fondation Gillet-Mérieux, Lyon-Sud Hospital, Pierre-Bénite, France; Center for Advanced Biotechnology and Medicine, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway; Division of Medical and Molecular Genetics, the Guy’s, King’s and St Thomas' School of Medicine, Guy’s Hospital, London; Department of Neurobiology, School of Life Science, Tottori University Faculty of Medicine, Yonago, Japan; and Institute of Inherited Metabolic Disorders, 1st Faculty of Medicine, Charles University, Prague
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48
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Sugimoto Y, Ninomiya H, Ohsaki Y, Higaki K, Davies JP, Ioannou YA, Ohno K. Accumulation of cholera toxin and GM1 ganglioside in the early endosome of Niemann-Pick C1-deficient cells. Proc Natl Acad Sci U S A 2001; 98:12391-6. [PMID: 11675488 PMCID: PMC60064 DOI: 10.1073/pnas.221181998] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2001] [Indexed: 11/18/2022] Open
Abstract
We investigated intracellular trafficking of GM1 ganglioside in Niemann-Pick C1 (NPC1)-deficient Chinese hamster ovary cells [NPC1(-) cells] by using cholera toxin (CT) as a probe. Both the holotoxin and the B subunit (CTB) accumulated in GM1-enriched intracellular vesicles of NPC1(-) cells. CTB-labeled vesicles contained the early endosome marker Rab5 but not lysosome-associated membrane protein 2 and were not labeled with either Texas red-transferrin or Lysotracker, indicating that they represent early endosomes. Similarly, CT accumulated in intracellular vesicles of human NPC fibroblasts that contained both Rab5 and early endosomal antigen 1. CTB accumulation in NPC1(-) cells was abolished by expression of wild-type NPC1 but not by mutant proteins with a mutation either in the NPC domain or the sterol-sensing domain. A part of these mutant NPC1 proteins expressed in NPC1(-) cells was localized on CTB-labeled vesicles. U18666A treatment of "knock in" cells [NPC1(-) cells that stably expressed wild-type NPC1] caused CTB accumulation similar to that in NPC1(-) cells, and a part of wild-type NPC1was localized on CTB-labeled vesicles in drug-treated cells. Finally, CT tracer experiments in NPC1(-) cells revealed retarded excretion of internalized toxin into the culture medium and an increase in the intracellular release of A subunits. In accordance with the latter result, CT was more effective in stimulating cAMP formation in NPC1(-) than in wild-type cells. These results suggest that transport of CT/GM1 complexes from the early endosome to the plasma membrane depends on the function of NPC1, whereas transport to the Golgi apparatus/endoplasmic reticulum does not.
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Affiliation(s)
- Y Sugimoto
- Department of Neurobiology, Tottori University Faculty of Medicine, Yonago 683, Japan
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49
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Millat G, Marçais C, Tomasetto C, Chikh K, Fensom AH, Harzer K, Wenger DA, Ohno K, Vanier MT. Niemann-Pick C1 disease: correlations between NPC1 mutations, levels of NPC1 protein, and phenotypes emphasize the functional significance of the putative sterol-sensing domain and of the cysteine-rich luminal loop. Am J Hum Genet 2001; 68:1373-85. [PMID: 11333381 PMCID: PMC1226124 DOI: 10.1086/320606] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2001] [Accepted: 03/28/2001] [Indexed: 11/03/2022] Open
Abstract
To obtain more information of the functional domains of the NPC1 protein, the mutational spectrum and the level of immunoreactive protein were investigated in skin fibroblasts from 30 unrelated patients with Niemann-Pick C1 disease. Nine of them were characterized by mild alterations of cellular cholesterol transport (the "variant" biochemical phenotype). The mutations showed a wide distribution to nearly all NPC1 domains, with a cluster (11/32) in a conserved NPC1 cysteine-rich luminal loop. Homozygous mutations in 14 patients and a phenotypically defined allele, combined with a new mutation, in a further 10 patients allowed genotype/phenotype correlations. Premature-termination-codon mutations, the three missense mutations in the sterol-sensing domain (SSD), and A1054T in the cysteine-rich luminal loop all occurred in patients with infantile neurological onset and "classic" (severe) cholesterol-trafficking alterations. By western blot, NPC1 protein was undetectable in the SSD missense mutations studied (L724P and Q775P) and essentially was absent in the A1054T missense allele. Our results thus enhance the functional significance of the SSD and demonstrate a correlation between the absence of NPC1 protein and the most severe neurological form. In the remaining missense mutations studied, corresponding to other disease presentations (including two adults with nonneurological disease), NPC1 protein was present in significant amounts of normal size, without clear-cut correlation with either the clinical phenotype or the "classic"/"variant" biochemical phenotype. Missense mutations in the cysteine-rich luminal loop resulted in a wide array of clinical and biochemical phenotypes. Remarkably, all five mutant alleles (I943M, V950M, G986S, G992R, and the recurrent P1007A) definitively correlated with the "variant" phenotype clustered within this loop, providing new insight on the functional complexity of the latter domain.
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Affiliation(s)
- Gilles Millat
- INSERM Unit 189, Lyon-Sud Medical School, Oullins, France; Clinical Biochemistry and Fondation Gillet-Mérieux, Lyon-Sud Hospital, Pierre-Bénite, Communaute Urbaine de Lyon; Institut de Génétique et de Biologie Moléculaire et Cellulaire, U184 INSERM/UPR 6520 CNRS/Université Louis Pasteur, Illkirch, Communaute Urbaine de Strasbourg; Division of Medical and Molecular Genetics, the Guy’s, King's and St Thomas School of Medicine, Guy's Hospital, London; Neurochemical Laboratory, Institut für Hirnforschung, University of Tübingen, Tübingen; Department of Neurology, Jefferson Medical College, Philadelphia; and Department of Neurobiology, School of Life Science, Tottori University Faculty of Medicine, Yonago, Japan
| | - Christophe Marçais
- INSERM Unit 189, Lyon-Sud Medical School, Oullins, France; Clinical Biochemistry and Fondation Gillet-Mérieux, Lyon-Sud Hospital, Pierre-Bénite, Communaute Urbaine de Lyon; Institut de Génétique et de Biologie Moléculaire et Cellulaire, U184 INSERM/UPR 6520 CNRS/Université Louis Pasteur, Illkirch, Communaute Urbaine de Strasbourg; Division of Medical and Molecular Genetics, the Guy’s, King's and St Thomas School of Medicine, Guy's Hospital, London; Neurochemical Laboratory, Institut für Hirnforschung, University of Tübingen, Tübingen; Department of Neurology, Jefferson Medical College, Philadelphia; and Department of Neurobiology, School of Life Science, Tottori University Faculty of Medicine, Yonago, Japan
| | - Catherine Tomasetto
- INSERM Unit 189, Lyon-Sud Medical School, Oullins, France; Clinical Biochemistry and Fondation Gillet-Mérieux, Lyon-Sud Hospital, Pierre-Bénite, Communaute Urbaine de Lyon; Institut de Génétique et de Biologie Moléculaire et Cellulaire, U184 INSERM/UPR 6520 CNRS/Université Louis Pasteur, Illkirch, Communaute Urbaine de Strasbourg; Division of Medical and Molecular Genetics, the Guy’s, King's and St Thomas School of Medicine, Guy's Hospital, London; Neurochemical Laboratory, Institut für Hirnforschung, University of Tübingen, Tübingen; Department of Neurology, Jefferson Medical College, Philadelphia; and Department of Neurobiology, School of Life Science, Tottori University Faculty of Medicine, Yonago, Japan
| | - Karim Chikh
- INSERM Unit 189, Lyon-Sud Medical School, Oullins, France; Clinical Biochemistry and Fondation Gillet-Mérieux, Lyon-Sud Hospital, Pierre-Bénite, Communaute Urbaine de Lyon; Institut de Génétique et de Biologie Moléculaire et Cellulaire, U184 INSERM/UPR 6520 CNRS/Université Louis Pasteur, Illkirch, Communaute Urbaine de Strasbourg; Division of Medical and Molecular Genetics, the Guy’s, King's and St Thomas School of Medicine, Guy's Hospital, London; Neurochemical Laboratory, Institut für Hirnforschung, University of Tübingen, Tübingen; Department of Neurology, Jefferson Medical College, Philadelphia; and Department of Neurobiology, School of Life Science, Tottori University Faculty of Medicine, Yonago, Japan
| | - Anthony H. Fensom
- INSERM Unit 189, Lyon-Sud Medical School, Oullins, France; Clinical Biochemistry and Fondation Gillet-Mérieux, Lyon-Sud Hospital, Pierre-Bénite, Communaute Urbaine de Lyon; Institut de Génétique et de Biologie Moléculaire et Cellulaire, U184 INSERM/UPR 6520 CNRS/Université Louis Pasteur, Illkirch, Communaute Urbaine de Strasbourg; Division of Medical and Molecular Genetics, the Guy’s, King's and St Thomas School of Medicine, Guy's Hospital, London; Neurochemical Laboratory, Institut für Hirnforschung, University of Tübingen, Tübingen; Department of Neurology, Jefferson Medical College, Philadelphia; and Department of Neurobiology, School of Life Science, Tottori University Faculty of Medicine, Yonago, Japan
| | - Klaus Harzer
- INSERM Unit 189, Lyon-Sud Medical School, Oullins, France; Clinical Biochemistry and Fondation Gillet-Mérieux, Lyon-Sud Hospital, Pierre-Bénite, Communaute Urbaine de Lyon; Institut de Génétique et de Biologie Moléculaire et Cellulaire, U184 INSERM/UPR 6520 CNRS/Université Louis Pasteur, Illkirch, Communaute Urbaine de Strasbourg; Division of Medical and Molecular Genetics, the Guy’s, King's and St Thomas School of Medicine, Guy's Hospital, London; Neurochemical Laboratory, Institut für Hirnforschung, University of Tübingen, Tübingen; Department of Neurology, Jefferson Medical College, Philadelphia; and Department of Neurobiology, School of Life Science, Tottori University Faculty of Medicine, Yonago, Japan
| | - David A. Wenger
- INSERM Unit 189, Lyon-Sud Medical School, Oullins, France; Clinical Biochemistry and Fondation Gillet-Mérieux, Lyon-Sud Hospital, Pierre-Bénite, Communaute Urbaine de Lyon; Institut de Génétique et de Biologie Moléculaire et Cellulaire, U184 INSERM/UPR 6520 CNRS/Université Louis Pasteur, Illkirch, Communaute Urbaine de Strasbourg; Division of Medical and Molecular Genetics, the Guy’s, King's and St Thomas School of Medicine, Guy's Hospital, London; Neurochemical Laboratory, Institut für Hirnforschung, University of Tübingen, Tübingen; Department of Neurology, Jefferson Medical College, Philadelphia; and Department of Neurobiology, School of Life Science, Tottori University Faculty of Medicine, Yonago, Japan
| | - K. Ohno
- INSERM Unit 189, Lyon-Sud Medical School, Oullins, France; Clinical Biochemistry and Fondation Gillet-Mérieux, Lyon-Sud Hospital, Pierre-Bénite, Communaute Urbaine de Lyon; Institut de Génétique et de Biologie Moléculaire et Cellulaire, U184 INSERM/UPR 6520 CNRS/Université Louis Pasteur, Illkirch, Communaute Urbaine de Strasbourg; Division of Medical and Molecular Genetics, the Guy’s, King's and St Thomas School of Medicine, Guy's Hospital, London; Neurochemical Laboratory, Institut für Hirnforschung, University of Tübingen, Tübingen; Department of Neurology, Jefferson Medical College, Philadelphia; and Department of Neurobiology, School of Life Science, Tottori University Faculty of Medicine, Yonago, Japan
| | - Marie T. Vanier
- INSERM Unit 189, Lyon-Sud Medical School, Oullins, France; Clinical Biochemistry and Fondation Gillet-Mérieux, Lyon-Sud Hospital, Pierre-Bénite, Communaute Urbaine de Lyon; Institut de Génétique et de Biologie Moléculaire et Cellulaire, U184 INSERM/UPR 6520 CNRS/Université Louis Pasteur, Illkirch, Communaute Urbaine de Strasbourg; Division of Medical and Molecular Genetics, the Guy’s, King's and St Thomas School of Medicine, Guy's Hospital, London; Neurochemical Laboratory, Institut für Hirnforschung, University of Tübingen, Tübingen; Department of Neurology, Jefferson Medical College, Philadelphia; and Department of Neurobiology, School of Life Science, Tottori University Faculty of Medicine, Yonago, Japan
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50
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Sun X, Marks DL, Park WD, Wheatley CL, Puri V, O’Brien JF, Kraft DL, Lundquist PA, Patterson MC, Pagano RE, Snow K. Niemann-Pick C variant detection by altered sphingolipid trafficking and correlation with mutations within a specific domain of NPC1. Am J Hum Genet 2001; 68:1361-72. [PMID: 11349231 PMCID: PMC1226123 DOI: 10.1086/320599] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2001] [Accepted: 04/03/2001] [Indexed: 11/04/2022] Open
Abstract
Niemann-Pick disease type C (NPC) is a fatal, autosomal recessive lipidosis characterized by lysosomal accumulation of unesterified cholesterol and multiple neurological symptoms, such as vertical supranuclear ophthalmoplegia, progressive ataxia, and dementia. More than 90% of cases of NPC are due to a defect in Niemann-Pick C1 (NPC1), a late endosomal, integral membrane protein that plays a role in cholesterol transport or homeostasis. Biochemical diagnosis of NPC has relied on the use of patient skin fibroblasts in an assay to demonstrate delayed low-density lipoprotein (LDL)-derived cholesterol esterification and a cytological technique-filipin staining-to demonstrate the intracellular accumulation of cholesterol. A small percentage of patients, referred to as "NPC variants," present with clinical symptoms of NPC but show near-normal results of these biochemical tests, making laboratory confirmation of NPC disease problematic. Here, we demonstrate that NPC-variant fibroblast samples can be detected as sphingolipid storage disease cells, using a fluorescent sphingolipid analog, BODIPY-lactosylceramide. This lipid accumulated in endosomes/lysosomes in variant cells preincubated with LDL cholesterol but targeted to the Golgi complex in normal cells under these conditions. The reproducibility of this technique was validated in a blinded study. In addition, we performed mutation analysis of the NPC1 gene in NPC variant and "classical" NPC cell samples and found a high incidence of specific mutations within the cysteine-rich region of NPC1 in variants. We also found that 5 of the 12 variant cell samples had no apparent defect in NPC1 but were otherwise indistinguishable from other variant cells. This is a surprising result, since, in general, approximately 90% of patients with NPC possess defects in NPC1. Our findings should be useful for the detection of NPC variants and also may provide significant new insight regarding NPC1 genotype/phenotype correlations.
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Affiliation(s)
- Xiaofeng Sun
- Thoracic Diseases Research Unit, Department of Biochemistry and Molecular Biology; Division of Laboratory Genetics, Department of Laboratory Medicine and Pathology; and Division of Child and Adolescent Neurology, Department of Neurology, Mayo Clinic and Foundation, Rochester, MN
| | - David L. Marks
- Thoracic Diseases Research Unit, Department of Biochemistry and Molecular Biology; Division of Laboratory Genetics, Department of Laboratory Medicine and Pathology; and Division of Child and Adolescent Neurology, Department of Neurology, Mayo Clinic and Foundation, Rochester, MN
| | - Walter D. Park
- Thoracic Diseases Research Unit, Department of Biochemistry and Molecular Biology; Division of Laboratory Genetics, Department of Laboratory Medicine and Pathology; and Division of Child and Adolescent Neurology, Department of Neurology, Mayo Clinic and Foundation, Rochester, MN
| | - Christine L. Wheatley
- Thoracic Diseases Research Unit, Department of Biochemistry and Molecular Biology; Division of Laboratory Genetics, Department of Laboratory Medicine and Pathology; and Division of Child and Adolescent Neurology, Department of Neurology, Mayo Clinic and Foundation, Rochester, MN
| | - Vishwajeet Puri
- Thoracic Diseases Research Unit, Department of Biochemistry and Molecular Biology; Division of Laboratory Genetics, Department of Laboratory Medicine and Pathology; and Division of Child and Adolescent Neurology, Department of Neurology, Mayo Clinic and Foundation, Rochester, MN
| | - John F. O’Brien
- Thoracic Diseases Research Unit, Department of Biochemistry and Molecular Biology; Division of Laboratory Genetics, Department of Laboratory Medicine and Pathology; and Division of Child and Adolescent Neurology, Department of Neurology, Mayo Clinic and Foundation, Rochester, MN
| | - Daniel L. Kraft
- Thoracic Diseases Research Unit, Department of Biochemistry and Molecular Biology; Division of Laboratory Genetics, Department of Laboratory Medicine and Pathology; and Division of Child and Adolescent Neurology, Department of Neurology, Mayo Clinic and Foundation, Rochester, MN
| | - Patrick A. Lundquist
- Thoracic Diseases Research Unit, Department of Biochemistry and Molecular Biology; Division of Laboratory Genetics, Department of Laboratory Medicine and Pathology; and Division of Child and Adolescent Neurology, Department of Neurology, Mayo Clinic and Foundation, Rochester, MN
| | - Marc C. Patterson
- Thoracic Diseases Research Unit, Department of Biochemistry and Molecular Biology; Division of Laboratory Genetics, Department of Laboratory Medicine and Pathology; and Division of Child and Adolescent Neurology, Department of Neurology, Mayo Clinic and Foundation, Rochester, MN
| | - Richard E. Pagano
- Thoracic Diseases Research Unit, Department of Biochemistry and Molecular Biology; Division of Laboratory Genetics, Department of Laboratory Medicine and Pathology; and Division of Child and Adolescent Neurology, Department of Neurology, Mayo Clinic and Foundation, Rochester, MN
| | - Karen Snow
- Thoracic Diseases Research Unit, Department of Biochemistry and Molecular Biology; Division of Laboratory Genetics, Department of Laboratory Medicine and Pathology; and Division of Child and Adolescent Neurology, Department of Neurology, Mayo Clinic and Foundation, Rochester, MN
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