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Caicedo PA, Serrato IM, Sim S, Dimopoulos G, Coatsworth H, Lowenberger C, Ocampo CB. Immune response-related genes associated to blocking midgut dengue virus infection in Aedes aegypti strains that differ in susceptibility. INSECT SCIENCE 2019; 26:635-648. [PMID: 29389079 DOI: 10.1111/1744-7917.12573] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 12/19/2017] [Accepted: 01/15/2018] [Indexed: 06/07/2023]
Abstract
Aedes (Stegomyia) aegypti, the principal global vector of dengue viruses, has differences in its susceptibility to dengue virus infection. We compared the global expression of genes in the midguts of Colombian Ae. aegypti dengue-susceptible (Cali-S) and dengue-refractory (Cali-MIB) field derived strains after ingesting either a sugarmeal, a bloodmeal, or a bloodmeal containing dengue virus serotype 2 (DENV-2). Microarray-based transcriptome analysis among treatments indicated a total of 4725 transcripts with differential expression between the two strains. Eleven genes were selected from different functional groups based on their significant up or down expression levels as well as reports in the literature suggesting they are associated with dengue virus elimination. We measured mRNA abundance of these 11 genes at 0, 8, 24, and 36 h postinfection using quantitative real time PCR (qPCR) to confirm the microarray results and assess any temporal patterns. Four genes were selected (Gram-negative binding protein-GNBP [AAEL009176], Niemann Pick Type-C2-NPC2 [AAEL015136], Keratinocyte lectin [AAEL009842], and Cathepsin-b [AAEL007585]) for knockdown experiments using RNA interference (RNAi) methodology to determine the phenotype (DENV-2 susceptible or refractory). Silencing GNBP, Cathepsin-b and Keratinocyte lectin reduced the percentage of mosquitoes with disseminated virus in the Cali-S strain to 8%, 20%, and 12% respectively compared with 96% in the controls. Silencing of NPC2 increased the percentage of mosquitos with disseminated virus infections in Cali-MIB to 66% compared with 35% in the controls. This study provides insight into genes that may contribute to the Cali-S susceptible and Cali-MIB refractory phenotypes in Ae. aegypti.
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Affiliation(s)
- Paola A Caicedo
- Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM), Cali, Colombia
| | - Idalba Mildred Serrato
- Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM), Cali, Colombia
| | - Shuzhen Sim
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
| | - George Dimopoulos
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
| | - Heather Coatsworth
- Department of Biological Sciences, Simon Fraser University, Burnaby, Canada
| | - Carl Lowenberger
- Department of Biological Sciences, Simon Fraser University, Burnaby, Canada
| | - Clara B Ocampo
- Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM), Cali, Colombia
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Formichi P, Battisti C, De Santi MM, Guazzo R, Tripodi SA, Radi E, Rossi B, Tarquini E, Federico A. Primary cilium alterations and expression changes of Patched1 proteins in niemann-pick type C disease. J Cell Physiol 2017; 233:663-672. [PMID: 28332184 DOI: 10.1002/jcp.25926] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 03/20/2017] [Indexed: 01/07/2023]
Abstract
Niemann-Pick type C disease (NPC) is a disorder characterized by abnormal intracellular accumulation of unesterified cholesterol and glycolipids. Two distinct disease-causing genes have been isolated, NPC1 and NPC2. The NPC1 protein is involved in the sorting and recycling of cholesterol and glycosphingolipids in the late endosomal/lysosomal system. It has extensive homology with the Patched1 (Ptc1) receptor, a transmembrane protein localized in the primary cilium, and involved in the Hedgehog signaling (Shh) pathway. We assessed the presence of NPC1 and Ptc1 proteins and evaluated the relative distribution and morphology of primary cilia in fibroblasts from five NPC1 patients and controls, and in normal fibroblasts treated with 3-ß-[2-(diethylamino)ethoxy]androst-5-en-17-one (U18666A), a cholesterol transport-inhibiting drug that is widely used to mimic NPC. Immunofluorescence and western blot analyses showed a significant decrease in expression of NPC1 and Ptc1 in NPC1 fibroblasts, while they were normally expressed in U18666A-treated fibroblasts. Moreover, fibroblasts from NPC1 patients and U18666A-treated cells showed a lower percentage distribution of primary cilia and a significant reduction in median cilia length with respect to controls. These are the first results demonstrating altered cytoplasmic expression of Ptc1 and reduced number and length of primary cilia, where Ptc1 is located, in fibroblasts from NPC1 patients. We suggest that the alterations in Ptc1 expression in cells from NPC1 patients are closely related to NPC1 expression deficit, while the primary cilia alterations observed in NPC1 and U18666A-treated fibroblasts may represent a secondary event derived from a defective metabolic pathway.
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Affiliation(s)
- Patrizia Formichi
- Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Carla Battisti
- Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | | | | | | | - Elena Radi
- Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | | | - Ermelinda Tarquini
- Unit of Clinic Neurology and Neurometabolic Diseases, AOU Siena, Siena, Italy
| | - Antonio Federico
- Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
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Loss of Niemann Pick type C proteins 1 and 2 greatly enhances HIV infectivity and is associated with accumulation of HIV Gag and cholesterol in late endosomes/lysosomes. Virol J 2012; 9:31. [PMID: 22273177 PMCID: PMC3299633 DOI: 10.1186/1743-422x-9-31] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Accepted: 01/24/2012] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Cholesterol pathways play an important role at multiple stages during the HIV-1 infection cycle. Here, we investigated the role of cholesterol trafficking in HIV-1 replication utilizing Niemann-Pick Type C disease (NPCD) cells as a model system. RESULTS We used a unique NPC2-deficient cell line (NPCD55) that exhibited Gag accumulation as well as decreased NPC1 expression after HIV infection. Virus release efficiency from NPCD55 cells was similar to that from control cells. However, we observed a 3 to 4-fold enhancement in the infectivity of virus released from these cells. Fluorescence microscopy revealed accumulation and co-localization of Gag proteins with cholesterol in late endosomal/lysosomal (LE/L) compartments of these cells. Virion-associated cholesterol was 4-fold higher in virions produced in NPCD55 cells relative to virus produced in control cells. Treatment of infected NPCD55 cells with the cholesterol efflux-inducing drug TO-9013171 reduced virus infectivity to control levels. CONCLUSIONS These results suggest cholesterol trafficking and localization can profoundly affect HIV-1 infectivity by modulating the cholesterol content of the virions.
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Abstract
PURPOSE Niemann-Pick disease type C1 (NPC1) is a genetic neurovisceral disorder characterized by abnormalities in intracellular sterol trafficking. A knockout mouse model (NPC1) is an important tool for the study of pathogenesis and treatment strategies. In the present study, NPC1 mice were examined for pathological changes in the cornea. METHODS Fifteen inbred homozygous NPC1 knockout mice (NPC1, 5-10 weeks old), 5 age-matched heterozygous mice (NPC1), and 14 wild-type control mice (NPC1) were examined. In vivo confocal laser scanning microscopy (CLSM) was performed on both eyes of each animal; afterward, the eyes were processed for histology, electron microscopy, and lipid analysis. RESULTS In vivo CLSM disclosed hyperreflective intracellular deposits in the intermediate and basal cell layers of corneal epithelium in all NPC1 mice. At the electron microscopy level, however, vacuolated cytoplasmic structures, 200-500 nm in diameter, with electron-dense material appeared in all structures investigated, including all epithelial layers and stromal keratocytes. These deposits were negative for filipin, a marker for unesterified cholesterol. Lipid analysis showed a marked increase in disialotetrahexosylganglioside 2 (GM2) level in NPC1 mice corneas, whereas no changes were detected in free cholesterol and disialotetrahexosylganglioside 3 (GM3) levels when compared with controls. CONCLUSIONS Morphological changes characteristic for the NPC1 mouse cornea were visualized in all epithelial layers and keratocytes. In vivo CLSM findings were confirmed by other techniques. In vivo detection of ocular manifestations and analysis of ocular tissue have the potential to aid the diagnosis of NPC1 disease and to monitor the efficacy of treatment.
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Zhang JR, Coleman T, Langmade SJ, Scherrer DE, Lane L, Lanier MH, Feng C, Sands MS, Schaffer JE, Semenkovich CF, Ory DS. Niemann-Pick C1 protects against atherosclerosis in mice via regulation of macrophage intracellular cholesterol trafficking. J Clin Invest 2008; 118:2281-90. [PMID: 18483620 DOI: 10.1172/jci32561] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2007] [Accepted: 04/09/2008] [Indexed: 11/17/2022] Open
Abstract
Niemann-Pick C1 (NPC1) is a key participant in cellular cholesterol trafficking. Loss of NPC1 function leads to defective suppression of SREBP-dependent gene expression and failure to appropriately activate liver X receptor-mediated (LXR-mediated) pathways, ultimately resulting in intracellular cholesterol accumulation. To determine whether NPC1 contributes to regulation of macrophage sterol homeostasis in vivo, we examined the effect of NPC1 deletion in BM-derived cells on atherosclerotic lesion development in the Ldlr-/- mouse model of atherosclerosis. High-fat diet-fed chimeric Npc1-/- mice reconstituted with Ldlr-/-Npc1-/- macrophages exhibited accelerated atherosclerosis despite lower serum cholesterol compared with mice reconstituted with wild-type macrophages. The discordance between the low serum lipoprotein levels and the presence of aortic atherosclerosis suggested that intrinsic alterations in macrophage sterol metabolism in the chimeric Npc1-/- mice played a greater role in atherosclerotic lesion formation than did serum lipoprotein levels. Macrophages from chimeric Npc1-/- mice showed decreased synthesis of 27-hydroxycholesterol (27-HC), an endogenous LXR ligand; decreased expression of LXR-regulated cholesterol transporters; and impaired cholesterol efflux. Lower 27-HC levels were associated with elevated cholesterol oxidation products in macrophages and plasma of chimeric Npc1-/- mice and with increased oxidative stress. Our results demonstrate that NPC1 serves an atheroprotective role in mice through regulation of LXR-dependent cholesterol efflux and mitigation of cholesterol-induced oxidative stress in macrophages.
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Affiliation(s)
- Jessie R Zhang
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
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Gorgas K, Teigler A, Komljenovic D, Just WW. The ether lipid-deficient mouse: Tracking down plasmalogen functions. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1763:1511-26. [PMID: 17027098 DOI: 10.1016/j.bbamcr.2006.08.038] [Citation(s) in RCA: 157] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2006] [Revised: 08/15/2006] [Accepted: 08/23/2006] [Indexed: 10/24/2022]
Abstract
Chemical and physico-chemical properties as well as physiological functions of major mammalian ether-linked glycerolipids, including plasmalogens were reviewed. Their chemical structures were described and their effect on membrane fluidity and membrane fusion discussed. The recent generation of mouse models with ether lipid deficiency offered the possibility to study ether lipid and particularly plasmalogen functions in vivo. Ether lipid-deficient mice revealed severe phenotypic alterations, including arrest of spermatogenesis, development of cataract and defects in central nervous system myelination. In several cell culture systems lack of plasmalogens impaired intracellular cholesterol distribution affecting plasma membrane functions and structural changes of ER and Golgi cisternae. Based on these phenotypic anomalies that were accurately described conclusions were drawn on putative functions of plasmalogens. These functions were related to cell-cell or cell-extracellular matrix interactions, formation of lipid raft microdomains and intracellular cholesterol homeostasis. There are several human disorders, such as Zellweger syndrome, rhizomelic chondrodysplasia punctata, Alzheimer's disease, Down syndrome, and Niemann-Pick type C disease that are distinguished by altered tissue plasmalogen concentrations. The role plasmalogens might play in the pathology of these disorders is discussed.
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Affiliation(s)
- Karin Gorgas
- Institut für Anatomie und Zellbiologie, Abteilung Medizinische Zellbiologie, Im Neuenheimer Feld 307, D-69120 Heidelberg, Germany
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Abstract
Lysosomal sequestration of endocytosed LDL-derived cholesterol, premature and abnormal enrichment of cholesterol in trans Golgi cisternae and accompanying anomalies in intracellular sterol trafficking are the hallmark phenotypic features of the Niemann-Pick C (NPC) lesion. A variable severity of these alterations has been observed, with only partial correlation between clinical and biochemical phenotypes. NPC also affects the metabolism of sphingolipids, and other biochemical abnormalities have been reported. Occurrence of neurofibrillary tangles in the brain of patients with a slowly progressive course is a recent intriguing observation. Genetic heterogeneity was established by cell hybridization and linkage studies. The two complementation groups could not be distinguished from each other by clinical, cellular or biochemical criteria, suggesting that the two gene products may interact or function sequentially. The major (> 90% of patients) NPC1 gene was mapped to 18q11 and recently isolated by positional cloning. The cDNA sequence predicts a 1278-amino acid protein, with 13 to 16 possible transmembrane regions and a putative cholesterol-sensing domain. Two murine models of the disease involving the same gene are known. The murine cDNA and the npc(nih) mutation have been characterized. Described homologies of the NPC1 protein are in line with its putative involvement in cellular cholesterol traffic.
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Affiliation(s)
- M T Vanier
- INSERM Unit 189, Lyon-Sud Medical School, Oullins, France.
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Paul CA, Reid PC, Boegle AK, Karten B, Zhang M, Jiang ZG, Franz D, Lin L, Chang TY, Vance JE, Blanchette-Mackie J, Maue RA. Adenovirus expressing an NPC1-GFP fusion gene corrects neuronal and nonneuronal defects associated with Niemann pick type C disease. J Neurosci Res 2005; 81:706-19. [PMID: 16015597 DOI: 10.1002/jnr.20592] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Niemann Pick type C (NPC) disease is an autosomal recessive disorder characterized by abnormal cholesterol metabolism and accumulation in lysosomal and endosomal compartments. Although peripheral organs are affected, the progressive neurodegeneration in the brain is typically most deleterious, leading to dystonia, ataxia, seizures, and premature death. Although the two genes underlying this disorder in humans and mouse models of the disease have been identified (NPC1 in 95% and NPC2/HE1 in 5% of human cases), their cellular roles have not Been fully defined, and there is currently no effective treatment for this disorder. To help address these issues, we constructed a recombinant adenovirus, Ad(NPC1-GFP), which contains a cDNA encoding a mouse NPC1 protein with a green fluorescent protein (GFP) fused to its C-terminus. Fluorescence microscopy and cholesterol trafficking assays demonstrate that the GFP-tagged NPC1 protein is functional and detectable in cells from different species (hamster, mouse, human) and of different types (ovary-derived cells, fibroblasts, astrocytes, neurons from peripheral and central nervous systems) in vitro. Combined with results from time-lapse microscopy and in vivo brain injections, our findings suggest that this adenovirus offers advantages for expressing NPC1 and analyzing its cellular localization, movement, functional properties, and beneficial effects in vitro and in vivo.
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Affiliation(s)
- C A Paul
- Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755, USA
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Paul CA, Boegle AK, Maue RA. Before the loss: neuronal dysfunction in Niemann-Pick Type C disease. Biochim Biophys Acta Mol Cell Biol Lipids 2004; 1685:63-76. [PMID: 15465427 DOI: 10.1016/j.bbalip.2004.08.012] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Niemann-Pick Type C (NPC) disease is an autosomal recessive disorder caused by mutations in either the NPC1 or HE1 genes. Hallmarks of this presently incurable disease include abnormal intracellular accumulation of cholesterol and glycosphingolipids, progressive neuropathology and neurodegeneration, and premature death. There have been increased efforts to understand the effects of NPC disease on neurons of the brain, in part due to the recent development of improved research tools and reagents, and in part due to the rapidly growing appreciation of the importance of cholesterol and lipoproteins in the brain during neuronal development, function, and degeneration. Here, we highlight fundamental aspects of neurons that appear to be affected by NPC disease, including their morphology, metabolism, intracellular transport, electrical signaling, and response to environmental factors, and suggest other potentially important areas for future investigation. This provides a framework for acquiring additional insight to this disorder and shaping new therapeutic approaches to NPC disease.
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Affiliation(s)
- Colleen A Paul
- Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755, USA
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Higaki K, Almanzar-Paramio D, Sturley SL. Metazoan and microbial models of Niemann-Pick Type C disease. Biochim Biophys Acta Mol Cell Biol Lipids 2004; 1685:38-47. [PMID: 15465425 DOI: 10.1016/j.bbalip.2004.08.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Niemann-Pick Type C (NP-C) disease compellingly provides insight into lipid transport and the association of this process with severe neuronal dysfunction. The two genes that define this syndrome, NPC1 and NPC2, are conserved throughout much of eukaryotic evolution, to the extent that the yeast and mammalian NPC1 genes are functionally interchangeable. We present here an evolutionary perspective of the genes defective in NP-C disease. We will describe how conservation of sequences and their biological roles in a variety of microbial and metazoan model systems may act as roadmaps to understanding this syndrome in humans.
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Affiliation(s)
- Katsumi Higaki
- The Institute of Human Nutrition, Columbia University College of Physicians and Surgeons, 630 W168th St. New York, NY 10032, USA
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11
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Abstract
Somatic cell hydridization and linkage studies indicated the implication of a second gene as a cause of Niemann-Pick C disease in a minority (5%) of patients. A study of the lysosomal proteome led to the identification of a previously known gene, HE1, as the NPC2 gene. The mature NPC2/HE1 protein is a ubiquitous soluble small 132-amino-acid glycoprotein, first characterized as a major secretory protein in the human epididymis, but also detected in most tissues. Seventeen families with mutations in the NPC2 gene are known. Good genotype-phenotype correlations were observed. No distinction can be made between the biochemical phenotypes of NPC1 or NPC2 mutants. The NPC2 protein binds cholesterol with submicromolar affinity at neutral and acidic pH. The bovine protein has been crystallized, and the cholesterol-binding site assigned to a hydrophobic loosely packed region. There is strong evidence that the NPC1 and NPC2 proteins must function in a closely related fashion. Current data have led to the hypothesis that NPC2 would bind cholesterol from internal lysosomal membranes, enabling a physical interaction with NPC1 (or another protein) and allowing postlysosomal export of cholesterol. In this model, the activity of NPC1 would depend on that of NPC2. The precise function of the NPC2 protein has, however, not been fully elucidated.
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Affiliation(s)
- Marie T Vanier
- INSERM Unit 189, Lyon-Sud Medical School and Fondation Gillet-Mérieux, Lyon-Sud University Hospital, 69495- Pierre-Bénite Cedex, France.
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12
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Abstract
Niemann-Pick disease, type C (NPC) is a progressive autosomal recessive neurodegenerative disease, characterized by late endosomal-lysosomal accumulation of multiple lipid molecules in association with abnormal tubulovesicular trafficking. The major gene product, NPC1 protein, is not suitable for transduction therapies, and gene replacement or repair is not yet practicable for NPC and related disorders. Attempts at therapy to date have focused on reduction of the accumulating molecules that are presumed to have direct or indirect toxic effects. More recent insights into the pathophysiology of NPC raise the possibility of small molecule therapies to interdict pathways triggering apoptosis and related routes to cell death and dysfunction.
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Affiliation(s)
- Marc C Patterson
- Division of Pediatric Neurology, Neurological Institute of New York and Columbia University College of Physicians and Surgeons, 180 Fort Washington Avenue, HP-542, New York, NY 10032, USA.
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Zhang J, Dudley-Rucker N, Crowley JR, Lopez-Perez E, Issandou M, Schaffer JE, Ory DS. The steroidal analog GW707 activates the SREBP pathway through disruption of intracellular cholesterol trafficking. J Lipid Res 2004; 45:223-31. [PMID: 14617742 DOI: 10.1194/jlr.m300409-jlr200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recently, a new class of lipid-lowering agents has been described that upregulate LDL receptor (LDLr) activity. These agents are proposed to activate sterol-regulated gene expression through binding to the sterol regulatory element binding protein (SREBP) cleavage-activating protein (SCAP). Here, we show that the steroidal LDLr upregulator, GW707, induces accumulation of lysosomal free cholesterol and inhibits LDL-stimulated cholesterol esterification, similar to that observed in U18666A-treated cells and in Niemann-Pick type C1 (NPC1) mutants. Moreover, we demonstrate that induction of the NPC-like phenotype by GW707 is independent of SCAP function. We find that treatment with GW707 does not increase SREBP-dependent gene expression above that observed in lipoprotein-starved cells. Rather, we show that the apparent increase in SREBP-dependent activity in GW707-treated cells is attributable to a failure to appropriately suppress sterol-regulated gene expression, as has been shown previously for U18666A-treated cells and NPC mutant fibroblasts. We further demonstrate that cells treated with either GW707 or U18666A fail to appropriately generate 27-hydroxycholesterol in response to LDL cholesterol. Taken together, these findings support a mechanism in which GW707 exerts its hypolipidemic effects through disruption of late endosomal/lysosomal sterol trafficking and subsequent stimulation of LDLr activity.
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Affiliation(s)
- Jessie Zhang
- Center for Cardiovascular Research, 91951 Les Ulis, France
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Frolov A, Zielinski SE, Crowley JR, Dudley-Rucker N, Schaffer JE, Ory DS. NPC1 and NPC2 regulate cellular cholesterol homeostasis through generation of low density lipoprotein cholesterol-derived oxysterols. J Biol Chem 2003; 278:25517-25. [PMID: 12719428 DOI: 10.1074/jbc.m302588200] [Citation(s) in RCA: 162] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutations in the Niemann-Pick disease genes cause lysosomal cholesterol accumulation and impaired low density lipoprotein (LDL) cholesterol esterification. These findings have been attributed to a block in cholesterol movement from lysosomes to the site of the sterol regulatory machinery. In this study we show that Niemann-Pick type C1 (NPC1) and Niemann-Pick type C2 (NPC2) mutants have increased cellular cholesterol, yet they are unable to suppress LDL receptor activity and cholesterol biosynthesis. Cholesterol overload in both NPC1 and NPC2 mutants results from the failure of LDL cholesterol tobothsuppresssterolregulatoryelement-bindingprotein-dependent gene expression and promote liver X receptor-mediated responses. However, the severity of the defect in regulation of sterol homeostasis does not correlate with endoplasmic reticulum cholesterol levels, but rather with the degree to which NPC mutant fibroblasts fail to appropriately generate 25-hydroxycholesterol and 27-hydroxycholesterol in response to LDL cholesterol. Moreover, we demonstrate that treatment with oxysterols reduces cholesterol in NPC mutants and is able to correct the NPC1I1061T phenotype, the most prevalent NPC1 disease genotype. Our findings support a role for NPC1 and NPC2 in the regulation of sterol homeostasis through generation of LDL cholesterol-derived oxysterols and have important implications for the treatment of NPC disease.
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Affiliation(s)
- Andrey Frolov
- Center for Cardiovascular Research, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110-1010, USA
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Abstract
What makes a heavy metal resistant bacterium heavy metal resistant? The mechanisms of action, physiological functions, and distribution of metal-exporting proteins are outlined, namely: CBA efflux pumps driven by proteins of the resistance-nodulation-cell division superfamily, P-type ATPases, cation diffusion facilitator and chromate proteins, NreB- and CnrT-like resistance factors. The complement of efflux systems of 63 sequenced prokaryotes was compared with that of the heavy metal resistant bacterium Ralstonia metallidurans. This comparison shows that heavy metal resistance is the result of multiple layers of resistance systems with overlapping substrate specificities, but unique functions. Some of these systems are widespread and serve in the basic defense of the cell against superfluous heavy metals, but some are highly specialized and occur only in a few bacteria. Possession of the latter systems makes a bacterium heavy metal resistant.
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Affiliation(s)
- Dietrich H Nies
- Institute of Microbiology, Molecular Microbiology, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Strasse 3, 06099 Halle/Saale, Germany.
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Walter M, Davies JP, Ioannou YA. Telomerase immortalization upregulates Rab9 expression and restores LDL cholesterol egress from Niemann-Pick C1 late endosomes. J Lipid Res 2003; 44:243-53. [PMID: 12576506 DOI: 10.1194/jlr.m200230-jlr200] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Niemann-Pick C (NPC) disease is a rare recessive lipidosis marked by excessive accumulation of LDL-derived free cholesterol and glycosphingolipids in the late endosomal-lysosomal (E-L) system. Here we report that ectopic expression of human telomerase reverse transcriptase (hTeRT) in human cells leads to an upregulation of the small GTPase Rab9 and its effector p40. Expression of hTeRT in NPC1 cells results in a correction of their cellular phenotype, including clearance of accumulated cholesterol from their E-L system. Specifically, in NPC1-TeRT cells, the transport of cholesterol from the E-L system to the plasma membrane is restored with a concomitant increase in cholesterol esterification. This effect is Rab9-specific since expression of Rab9 in untransformed NPC1 cells also leads to a reversal of their disease phenotype. These effects are also seen in normal TeRT-immortalized cells and it appears that TeRT expression leads to an increase in the transport of molecules, including cholesterol, from the E-L system, and may play a role in increasing cellular proliferation. These results suggest the existence of alternative endogenous therapeutic targets that can be modulated to reverse the NPC1 disease phenotype.
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Affiliation(s)
- Marc Walter
- Department of Human Genetics, Mount Sinai School of Medicine, New York, NY 10029, USA
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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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Frolov A, Srivastava K, Daphna-Iken D, Traub LM, Schaffer JE, Ory DS. Cholesterol overload promotes morphogenesis of a Niemann-Pick C (NPC)-like compartment independent of inhibition of NPC1 or HE1/NPC2 function. J Biol Chem 2001; 276:46414-21. [PMID: 11571306 DOI: 10.1074/jbc.m108099200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cholesterol accumulation in an aberrant endosomal/lysosomal compartment is the hallmark of Niemann-Pick type C (NPC) disease. To gain insight into the etiology of the NPC compartment, we studied a novel Chinese hamster ovary cell mutant that was identified through a genetic screen and phenocopies the NPC1 mutation. We show that the M87 mutant harbors a mutation in a gene distinct from the NPC1 and HE1/NPC2 disease genes. M87 cells have increased total cellular cholesterol with accumulation in an aberrant compartment that contains LAMP-1, LAMP-2, and NPC1, but not CI-MPR, similar to the cholesterol-rich compartment in NPC mutant cells. We demonstrate that low-density lipoprotein receptor activity is increased 3-fold in the M87 mutant, and likely contributes to accumulation of excess cholesterol. In contrast to NPC1-null cells, the M87 mutant exhibits normal rates of delivery of endosomal cholesterol to the endoplasmic reticulum and to the plasma membrane. The preserved late endosomal function in the M87 mutant is associated with the presence of NPC1-containing multivesicular late endosomes and supports a role for these multivesicular late endosomes in the sorting and distribution of cholesterol. Our findings implicate cholesterol overload in the formation of an NPC-like compartment that is independent of inhibition of NPC1 or HE1/NPC2 function.
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Affiliation(s)
- A Frolov
- Center for Cardiovascular Research, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110-1010, USA
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20
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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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21
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Naureckiene S, Sleat DE, Lackland H, Fensom A, Vanier MT, Wattiaux R, Jadot M, Lobel P. Identification of HE1 as the second gene of Niemann-Pick C disease. Science 2000; 290:2298-301. [PMID: 11125141 DOI: 10.1126/science.290.5500.2298] [Citation(s) in RCA: 627] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Niemann-Pick type C2 disease (NP-C2) is a fatal hereditary disorder of unknown etiology characterized by defective egress of cholesterol from lysosomes. Here we show that the disease is caused by a deficiency in HE1, a ubiquitously expressed lysosomal protein identified previously as a cholesterol-binding protein. HE1 was undetectable in fibroblasts from NP-C2 patients but present in fibroblasts from unaffected controls and NP-C1 patients. Mutations in the HE1 gene, which maps to chromosome 14q24.3, were found in NP-C2 patients but not in controls. Treatment of NP-C2 fibroblasts with exogenous recombinant HE1 protein ameliorated lysosomal accumulation of low density lipoprotein-derived cholesterol.
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Affiliation(s)
- S Naureckiene
- Center for Advanced Biotechnology and Medicine, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, NJ, 08854, USA
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22
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Ory DS. Niemann-Pick type C: a disorder of cellular cholesterol trafficking. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1529:331-9. [PMID: 11111100 DOI: 10.1016/s1388-1981(00)00158-x] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- D S Ory
- Department of Internal Medicine, Washington University, School of Medicine, 660 S Euclid Avenue, St Louis, MO 63110-1093, USA.
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Davies JP, Ioannou YA. Topological analysis of Niemann-Pick C1 protein reveals that the membrane orientation of the putative sterol-sensing domain is identical to those of 3-hydroxy-3-methylglutaryl-CoA reductase and sterol regulatory element binding protein cleavage-activating protein. J Biol Chem 2000; 275:24367-74. [PMID: 10821832 DOI: 10.1074/jbc.m002184200] [Citation(s) in RCA: 226] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Niemann-Pick C1 (NPC1) protein is predicted to be a polytopic glycoprotein, and it contains a region with extensive homology to the sterol-sensing domains (SSD) of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-R) and sterol regulatory element binding protein cleavage-activating protein (SCAP). To aid the functional characterization of NPC1, a model of NPC1 topology was evaluated by expression of epitope-tagged NPC1 proteins and investigation of epitope accessibility in selectively permeabilized cells. These results were further confirmed by expression of NPC1 and identification of glycosylated domains that are located in the lumen of the endoplasmic reticulum. Our data indicate that this glycoprotein contains 13 transmembrane domains, 3 large and 4 small luminal loops, 6 small cytoplasmic loops, and a cytoplasmic tail. Furthermore, our data show that the putative SSD of NPC1 is oriented in the same manner as those of HMG-R and SCAP, providing strong evidence that this domain is functionally important.
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Affiliation(s)
- J P Davies
- Department of Human Genetics, Mount Sinai School of Medicine, New York, New York 10029, USA
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24
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Abstract
Niemann-Pick disease, originally defined in terms of its histology as a reticuloendotheliosis, is now subdivided on the basis of biochemical and molecular criteria into two separate classes. This categorization has been aided by the discovery of the genes for acid sphingomyelinase, deficient in types A and B, and for the NPC-1 protein, deficient in types C and D, and the finding of mutations in each. Animal models of type A and type C disease are known or have been developed. These models have been utilized in therapeutic trials of bone marrow transplantation and gene transfection of stem cells and in studies of disease pathogenesis. Lysosphingomyelin has been implicated in the nervous system involvement associated with type A disease in humans and accumulations of the NPC-1 protein and apolipoprotein D have been found in murine NP-C brain. Cells from both human and murine Niemann-Pick disease type A have been studied to assess the role of acid sphingomyelinase in signal transduction pathways involving cell proliferation, differentiation, and apoptosis.
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Affiliation(s)
- E H Kolodny
- New York University School of Medicine, Department of Neurology, New York 10016, USA
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25
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Abstract
Niemann-Pick type C (NPC) is an autosomal recessive lysosomal storage disease. Fibroblasts from individuals with Niemann-Pick type C exhibit defective intracellular cholesterol transport. Linkage analysis has led to the recent cloning of the NPC1 gene on human chromosome 18, which is the major disease locus. Analysis of NPC1 reveals homologies with key regulators of cholesterol homeostasis and a Drosophila morphogen receptor.
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Affiliation(s)
- L Liscum
- Department of Physiology, Tufts University School of Medicine, Boston, MA 02111, USA
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