1
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The Consequences of GBA Deficiency in the Autophagy-Lysosome System in Parkinson's Disease Associated with GBA. Cells 2023; 12:cells12010191. [PMID: 36611984 PMCID: PMC9818455 DOI: 10.3390/cells12010191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/27/2022] [Accepted: 12/31/2022] [Indexed: 01/05/2023] Open
Abstract
GBA gene variants were the first genetic risk factor for Parkinson's disease. GBA encodes the lysosomal enzyme glucocerebrosidase (GBA), which is involved in sphingolipid metabolism. GBA exhibits a complex physiological function that includes not only the degradation of its substrate glucosylceramide but also the metabolism of other sphingolipids and additional lipids such as cholesterol, particularly when glucocerebrosidase activity is deficient. In the context of Parkinson's disease associated with GBA, the loss of GBA activity has been associated with the accumulation of α-synuclein species. In recent years, several hypotheses have proposed alternative and complementary pathological mechanisms to explain why lysosomal enzyme mutations lead to α-synuclein accumulation and become important risk factors in Parkinson's disease etiology. Classically, loss of GBA activity has been linked to a dysfunctional autophagy-lysosome system and to a subsequent decrease in autophagy-dependent α-synuclein turnover; however, several other pathological mechanisms underlying GBA-associated parkinsonism have been proposed. This review summarizes and discusses the different hypotheses with a special focus on autophagy-dependent mechanisms, as well as autophagy-independent mechanisms, where the role of other players such as sphingolipids, cholesterol and other GBA-related proteins make important contributions to Parkinson's disease pathogenesis.
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2
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Barral DC, Staiano L, Guimas Almeida C, Cutler DF, Eden ER, Futter CE, Galione A, Marques ARA, Medina DL, Napolitano G, Settembre C, Vieira OV, Aerts JMFG, Atakpa‐Adaji P, Bruno G, Capuozzo A, De Leonibus E, Di Malta C, Escrevente C, Esposito A, Grumati P, Hall MJ, Teodoro RO, Lopes SS, Luzio JP, Monfregola J, Montefusco S, Platt FM, Polishchuck R, De Risi M, Sambri I, Soldati C, Seabra MC. Current methods to analyze lysosome morphology, positioning, motility and function. Traffic 2022; 23:238-269. [PMID: 35343629 PMCID: PMC9323414 DOI: 10.1111/tra.12839] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 03/21/2022] [Accepted: 03/22/2022] [Indexed: 01/09/2023]
Abstract
Since the discovery of lysosomes more than 70 years ago, much has been learned about the functions of these organelles. Lysosomes were regarded as exclusively degradative organelles, but more recent research has shown that they play essential roles in several other cellular functions, such as nutrient sensing, intracellular signalling and metabolism. Methodological advances played a key part in generating our current knowledge about the biology of this multifaceted organelle. In this review, we cover current methods used to analyze lysosome morphology, positioning, motility and function. We highlight the principles behind these methods, the methodological strategies and their advantages and limitations. To extract accurate information and avoid misinterpretations, we discuss the best strategies to identify lysosomes and assess their characteristics and functions. With this review, we aim to stimulate an increase in the quantity and quality of research on lysosomes and further ground-breaking discoveries on an organelle that continues to surprise and excite cell biologists.
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Affiliation(s)
- Duarte C. Barral
- CEDOC, NOVA Medical School, NMS, Universidade NOVA de LisboaLisbonPortugal
| | - Leopoldo Staiano
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
- Institute for Genetic and Biomedical ResearchNational Research Council (CNR)MilanItaly
| | | | - Dan F. Cutler
- MRC Laboratory for Molecular Cell BiologyUniversity College LondonLondonUK
| | - Emily R. Eden
- University College London (UCL) Institute of OphthalmologyLondonUK
| | - Clare E. Futter
- University College London (UCL) Institute of OphthalmologyLondonUK
| | | | | | - Diego Luis Medina
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
- Medical Genetics Unit, Department of Medical and Translational ScienceFederico II UniversityNaplesItaly
| | - Gennaro Napolitano
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
- Medical Genetics Unit, Department of Medical and Translational ScienceFederico II UniversityNaplesItaly
| | - Carmine Settembre
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
- Clinical Medicine and Surgery DepartmentFederico II UniversityNaplesItaly
| | - Otília V. Vieira
- CEDOC, NOVA Medical School, NMS, Universidade NOVA de LisboaLisbonPortugal
| | | | | | - Gemma Bruno
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
| | | | - Elvira De Leonibus
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
- Institute of Biochemistry and Cell Biology, CNRRomeItaly
| | - Chiara Di Malta
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
- Medical Genetics Unit, Department of Medical and Translational ScienceFederico II UniversityNaplesItaly
| | | | | | - Paolo Grumati
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
| | - Michael J. Hall
- CEDOC, NOVA Medical School, NMS, Universidade NOVA de LisboaLisbonPortugal
| | - Rita O. Teodoro
- CEDOC, NOVA Medical School, NMS, Universidade NOVA de LisboaLisbonPortugal
| | - Susana S. Lopes
- CEDOC, NOVA Medical School, NMS, Universidade NOVA de LisboaLisbonPortugal
| | - J. Paul Luzio
- Cambridge Institute for Medical ResearchUniversity of CambridgeCambridgeUK
| | | | | | | | | | - Maria De Risi
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
| | - Irene Sambri
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
- Medical Genetics Unit, Department of Medical and Translational ScienceFederico II UniversityNaplesItaly
| | - Chiara Soldati
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
| | - Miguel C. Seabra
- CEDOC, NOVA Medical School, NMS, Universidade NOVA de LisboaLisbonPortugal
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3
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Boer DE, Mirzaian M, Ferraz MJ, Zwiers KC, Baks MV, Hazeu MD, Ottenhoff R, Marques ARA, Meijer R, Roos JCP, Cox TM, Boot RG, Pannu N, Overkleeft HS, Artola M, Aerts JM. Human glucocerebrosidase mediates formation of xylosyl-cholesterol by β-xylosidase and transxylosidase reactions. J Lipid Res 2021; 62:100018. [PMID: 33361282 PMCID: PMC7903134 DOI: 10.1194/jlr.ra120001043] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 12/14/2020] [Accepted: 12/23/2020] [Indexed: 11/20/2022] Open
Abstract
Deficiency of glucocerebrosidase (GBA), a lysosomal β-glucosidase, causes Gaucher disease. The enzyme hydrolyzes β-glucosidic substrates and transglucosylates cholesterol to cholesterol-β-glucoside. Here we show that recombinant human GBA also cleaves β-xylosides and transxylosylates cholesterol. The xylosyl-cholesterol formed acts as an acceptor for the subsequent formation of di-xylosyl-cholesterol. Common mutant forms of GBA from patients with Gaucher disease with reduced β-glucosidase activity were similarly impaired in β-xylosidase, transglucosidase, and transxylosidase activities, except for a slightly reduced xylosidase/glucosidase activity ratio of N370S GBA and a slightly reduced transglucosylation/glucosidase activity ratio of D409H GBA. XylChol was found to be reduced in spleen from patients with Gaucher disease. The origin of newly identified XylChol in mouse and human tissues was investigated. Cultured human cells exposed to exogenous β-xylosides generated XylChol in a manner dependent on active lysosomal GBA but not the cytosol-facing β-glucosidase GBA2. We later sought an endogenous β-xyloside acting as donor in transxylosylation reactions, identifying xylosylated ceramide (XylCer) in cells and tissues that serve as donor in the formation of XylChol. UDP-glucosylceramide synthase (GCS) was unable to synthesize XylChol but could catalyze the formation of XylCer. Thus, food-derived β-D-xyloside and XylCer are potential donors for the GBA-mediated formation of XylChol in cells. The enzyme GCS produces XylCer at a low rate. Our findings point to further catalytic versatility of GBA and prompt a systematic exploration of the distribution and role of xylosylated lipids.
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Affiliation(s)
- Daphne E Boer
- Department of Medical Biochemistry, Leiden Institute of Chemistry, Leiden University, The Netherlands
| | - Mina Mirzaian
- Department of Medical Biochemistry, Leiden Institute of Chemistry, Leiden University, The Netherlands
| | - Maria J Ferraz
- Department of Medical Biochemistry, Leiden Institute of Chemistry, Leiden University, The Netherlands
| | - Kimberley C Zwiers
- Department of Medical Biochemistry, Leiden Institute of Chemistry, Leiden University, The Netherlands
| | - Merel V Baks
- Department of Medical Biochemistry, Leiden Institute of Chemistry, Leiden University, The Netherlands
| | - Marc D Hazeu
- Department of Medical Biochemistry, Leiden Institute of Chemistry, Leiden University, The Netherlands
| | - Roelof Ottenhoff
- Department of Medical Biochemistry, Academic Medical Center, Amsterdam, The Netherlands
| | - André R A Marques
- Department of Medical Biochemistry, Leiden Institute of Chemistry, Leiden University, The Netherlands
| | - Rianne Meijer
- Department of Medical Biochemistry, Leiden Institute of Chemistry, Leiden University, The Netherlands
| | - Jonathan C P Roos
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Timothy M Cox
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Rolf G Boot
- Department of Medical Biochemistry, Leiden Institute of Chemistry, Leiden University, The Netherlands
| | - Navraj Pannu
- Department of Biophysical Structural Chemistry, Leiden Institute of Chemistry, Leiden University, The Netherlands
| | - Herman S Overkleeft
- Department of Bio-organic Synthesis, Leiden Institute of Chemistry, Leiden University, The Netherlands
| | - Marta Artola
- Department of Medical Biochemistry, Leiden Institute of Chemistry, Leiden University, The Netherlands
| | - Johannes M Aerts
- Department of Medical Biochemistry, Leiden Institute of Chemistry, Leiden University, The Netherlands.
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4
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Hoitsema K, Amato D, Khan A, Sirrs S, Choy FYM. Identification of novel splice site mutation IVS9 + 1(G > A) and novel complex allele G355R/R359X in Type 1 Gaucher patients heterozygous for mutation N370S. Meta Gene 2016; 9:47-51. [PMID: 27222815 PMCID: PMC4856859 DOI: 10.1016/j.mgene.2016.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 02/27/2016] [Accepted: 03/17/2016] [Indexed: 11/30/2022] Open
Abstract
Gaucher disease is an autosomal recessive lysosomal storage disorder resulting from deficient glucocerebrosidase activity. More than 350 mutations that cause Gaucher disease have been described to date. Novel mutations can potentially provide insight into the glucocerebrosidase structure–function relationship and biochemical basis of the disease. Here, we report the identification of two novel mutations in two unrelated patients with type I (non-neuronopathic) Gaucher disease: 1) a splice site mutation IVS9 + 1G > A; and (2) a complex allele (cis) G355R/R359X. Both patients have a common N370S mutation in the other allele. The splice site mutation results from an intronic base substitution (G to A, c.1328 + 1, g.5005) at the donor splice site of exon and intron 9. The complex allele results from two point mutations in exon 8 of glucocerebrosidase (G to C at c.1180, g.4396, and T to C at c. 1192, g.4408) substituting glycine by arginine (G355R) and arginine by a premature termination (R359X), respectively. In order to demonstrate that G355R/R359X are in cis arrangement, PCR-amplified glucocerebrosidase exon 8 genomic DNA from the patient was cloned into the vector pJET1.2 in Escherichia coli TOP10® strain. Out of the 15 clones that were sequence analyzed, 10 contained the normal allele sequence and 5 contained the complex allele G355R/R359X sequence showing both mutations in cis arrangement. Restriction fragment length polymorphism analysis using Hph1 restriction endonuclease digest was established for the IVS9 + 1G > A mutation for confirmation and efficient identification of this mutation in future patients. Past literature suggests that mutations affecting splicing patterns of the glucocerebrosidase transcript as well as mutations in Gaucher complex alleles are detrimental to enzyme activity. However, compound heterozygosity with N370S, a mild mutation, will lead to a mild phenotype. The cases reported here support these past findings.
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Key Words
- Complex alleles
- EC, enzyme commission number
- GBA novel mutations
- GBA, glucocerebrosidase enzyme protein
- GBA, glucocerebrosidase gene
- GD, Gaucher disease
- Gaucher disease
- Glucocerebrosidase
- Hb, hemoglobin
- MRI, magnetic resonance imaging
- OMIM, Online Mendelian Inheritance in Man entry number
- PCR, polymerase chain reaction
- RFLP analysis
- RFLP, restriction fragment length polymorphism
- RT-PCR, reverse transcription-PCR
- Sequence analysis
- bp, base pairs
- pJET cloning
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Affiliation(s)
- Kourtnee Hoitsema
- Department of Biology, Centre for Biomedical Research, University of Victoria, British Columbia, Canada
| | - Dominick Amato
- Mark Freedman and Judy Jacobs Program for Gaucher Disease, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Aneal Khan
- Department of Medical Genetics, University of Calgary, Alberta Children's Hospital, Calgary, Alberta, Canada; Department of Pediatrics, University of Calgary, Alberta Children's Hospital, Calgary, Alberta, Canada
| | - Sandra Sirrs
- Department of Medicine, Division of Endocrinology, University of British Columbia, Canada
| | - Francis Y M Choy
- Department of Biology, Centre for Biomedical Research, University of Victoria, British Columbia, Canada
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5
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Tamargo RJ, Velayati A, Goldin E, Sidransky E. The role of saposin C in Gaucher disease. Mol Genet Metab 2012; 106:257-63. [PMID: 22652185 PMCID: PMC3534739 DOI: 10.1016/j.ymgme.2012.04.024] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Revised: 04/28/2012] [Accepted: 04/29/2012] [Indexed: 12/16/2022]
Abstract
Saposin C is one of four homologous proteins derived from sequential cleavage of the saposin precursor protein, prosaposin. It is an essential activator for glucocerebrosidase, the enzyme deficient in Gaucher disease. Gaucher disease is a rare autosomal recessive lysosomal storage disorder caused by mutations in the GBA gene that exhibits vast phenotypic heterogeneity, despite its designation as a "simple" Mendelian disorder. The observed phenotypic variability has led to a search for disease modifiers that can alter the Gaucher phenotype. The PSAP gene encoding saposin C is a prime candidate modifier for Gaucher disease. In humans, saposin C deficiency due to mutations in PSAP results in a Gaucher-like phenotype, despite normal in vitro glucocerebrosidase activity. Saposin C deficiency has also been shown to modify phenotype in one mouse model of Gaucher disease. The role of saposin C as an activator required for normal glucocerebrosidase function, and the consequences of saposin C deficiency are described, and are being explored as potential modifying factors in patients with Gaucher disease.
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Affiliation(s)
- Rafael J. Tamargo
- Section on Molecular Neurogenetics, Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Arash Velayati
- Section on Molecular Neurogenetics, Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Ehud Goldin
- Section on Molecular Neurogenetics, Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Ellen Sidransky
- Section on Molecular Neurogenetics, Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
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6
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Detection of mutant protein in complex biological samples: Glucocerebrosidase mutations in Gaucher’s disease. Anal Biochem 2008; 372:52-61. [DOI: 10.1016/j.ab.2007.09.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2007] [Revised: 08/28/2007] [Accepted: 09/25/2007] [Indexed: 11/20/2022]
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7
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Molecular imaging of membrane interfaces reveals mode of beta-glucosidase activation by saposin C. Proc Natl Acad Sci U S A 2007; 104:17394-9. [PMID: 17954913 DOI: 10.1073/pnas.0704998104] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Acid beta-glucosidase (GCase) is a soluble lysosomal enzyme responsible for the hydrolysis of glucose from glucosylceramide and requires activation by the small nonenzymatic protein saposin C (sapC) to gain access to the membrane-embedded glycosphingolipid substrate. We have used in situ atomic force microscopy (AFM) with simultaneous confocal and epifluorescence microscopies to investigate the interactions of GCase and sapC with lipid bilayers. GCase binds to sites on membranes transformed by sapC, and enzyme activity occurs at loci containing both GCase and sapC. Using FRET, we establish the presence of GCase/sapC and GCase/product contacts in the bilayer. These data support a mechanism in which sapC locally alters regions of bilayer for subsequent attack by the enzyme in stably bound protein complexes.
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8
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Salvioli R, Tatti M, Scarpa S, Moavero S, Ciaffoni F, Felicetti F, Kaneski C, Brady R, Vaccaro A. The N370S (Asn370-->Ser) mutation affects the capacity of glucosylceramidase to interact with anionic phospholipid-containing membranes and saposin C. Biochem J 2005; 390:95-103. [PMID: 15826241 PMCID: PMC1184565 DOI: 10.1042/bj20050325] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The properties of the endolysosomal enzyme GCase (glucosylceramidase), carrying the most prevalent mutation observed in Gaucher patients, namely substitution of an asparagine residue with a serine at amino acid position 370 [N370S (Asn370-->Ser) GCase], were investigated in the present study. We previously demonstrated that Sap (saposin) C, the physiological GCase activator, promotes the association of GCase with anionic phospholipid-containing membranes, reconstituting in this way the enzyme activity. In the present study, we show that, in the presence of Sap C and membranes containing high levels of anionic phospholipids, both normal and N370S GCases are able to associate with the lipid surface and to express their activity. Conversely, when the amount of anionic phospholipids in the membrane is reduced (approximately 20% of total lipids), Sap C is still able to promote binding and activation of the normal enzyme, but not of N370S GCase. The altered interaction of the mutated enzyme with anionic phospholipid-containing membranes and Sap C was further demonstrated in Gaucher fibroblasts by confocal microscopy, which revealed poor co-localization of N370S GCase with Sap C and lysobisphosphatidic acid, the most abundant anionic phospholipid in endolysosomes. Moreover, we found that N370S Gaucher fibroblasts accumulate endolysosomal free cholesterol, a lipid that might further interfere with the interaction of the enzyme with Sap C and lysobisphosphatidic acid-containing membranes. In summary, our results show that the N370S mutation primarily affects the interaction of GCase with its physiological activators, namely Sap C and anionic phospholipid-containing membranes. We thus propose that the poor contact between N370S GCase and its activators may be responsible for the low activity of the mutant enzyme in vivo.
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Affiliation(s)
- Rosa Salvioli
- *Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore Sanita', Viale Regina Elena 299, 00161 Roma, Italy
| | - Massimo Tatti
- *Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore Sanita', Viale Regina Elena 299, 00161 Roma, Italy
| | - Susanna Scarpa
- †Department of Experimental Medicine and Pathology, University of Rome ‘La Sapienza’, Viale Regina Elena 234, 00161 Roma, Italy
| | - Sabrina Maria Moavero
- *Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore Sanita', Viale Regina Elena 299, 00161 Roma, Italy
| | - Fiorella Ciaffoni
- *Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore Sanita', Viale Regina Elena 299, 00161 Roma, Italy
| | - Federica Felicetti
- *Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore Sanita', Viale Regina Elena 299, 00161 Roma, Italy
| | - Christine R. Kaneski
- ‡Developmental and Metabolic Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, U.S.A
| | - Roscoe O. Brady
- ‡Developmental and Metabolic Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, U.S.A
| | - Anna Maria Vaccaro
- *Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore Sanita', Viale Regina Elena 299, 00161 Roma, Italy
- To whom correspondence should be addressed (email )
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Salvioli R, Scarpa S, Ciaffoni F, Tatti M, Ramoni C, Vanier MT, Vaccaro AM. Glucosylceramidase mass and subcellular localization are modulated by cholesterol in Niemann-Pick disease type C. J Biol Chem 2004; 279:17674-80. [PMID: 14757764 DOI: 10.1074/jbc.m313517200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Niemann-Pick disease type C (NPC) is characterized by the accumulation of cholesterol and sphingolipids in the late endosomal/lysosomal compartment. The mechanism by which the concentration of sphingolipids such as glucosylceramide is increased in this disease is poorly understood. We have found that, in NPC fibroblasts, the cholesterol storage affects the stability of glucosylceramidase (GCase), decreasing its mass and activity; a reduction of cholesterol raises the level of GCase to nearly normal values. GCase is activated and stabilized by saposin C (Sap C) and anionic phospholipids. Here we show by immunofluorescence microscopy that in normal fibroblasts, GCase, Sap C, and lysobisphosphatidic acid (LBPA), the most abundant anionic phospholipid in the endolysosomal system, reside in the same intracellular vesicular structures. In contrast, the colocalization of GCase, Sap C, and LBPA is markedly impaired in NPC fibroblasts but can be re-established by cholesterol depletion. These data show for the first time that the level of cholesterol modulates the interaction of GCase with its protein and lipid activators, namely Sap C and LBPA, regulating the GCase activity and stability.
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Affiliation(s)
- Rosa Salvioli
- Department of Hematology, Istituto Superiore Sanita', 00161 Roma, Italy
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10
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Detection and Isolation of Gene-Corrected Cells in Gaucher Disease Via a Fluorescence-Activated Cell Sorter Assay for Lysosomal Glucocerebrosidase Activity. Blood 1997. [DOI: 10.1182/blood.v89.9.3412] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractGaucher disease type 1 results from the accumulation of glucocerebroside in macrophages of the reticuloendothelial system, as a consequence of a deficiency in glucocerebrosidase (GC) activity. Recent improvements in the methodologies for introducing foreign genes into bone marrow stem cells have prompted several groups to test the efficacy of gene transfer therapy as a curative treatment for Gaucher disease. Limitations of this approach include the potential for insufficient engraftment of gene-corrected cells and incomplete transduction of hematopoietic stem cells using retroviral gene transfer. Overcoming these obstacles may be critical in the case of treatment for Gaucher disease type 1, because GC transduced cells have not been shown to have a growth advantage over noncorrected cells. Here, we describe the development and application of a novel, fluorescence-activated cell sorter based assay that directly quantitates GC activity at the single cell level. In a test of this application, fibroblasts from a Gaucher patient were transduced, and high expressing cells sorted based on GC activity. Reanalysis of cultured sorted fibroblasts reveals that these cells maintain high levels of enzymatic activity, compared with the heterogeneous population from which they were sorted. The assay is sufficiently sensitive to distinguish GC activity found in Gaucher patient monocytes from that in normal controls. Furthermore, preliminary results indicate that increased GC activity can be detected in transduced, CD34+ enriched peripheral blood mononuclear cells isolated from a Gaucher patient. This method should be a useful addition to current gene therapy protocols as a means to quantitatively assess gene correction of relevant cell populations and potentially purify transduced cells for transplantation.
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11
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Matern H, Heinemann H, Legler G, Matern S. Purification and characterization of a microsomal bile acid beta-glucosidase from human liver. J Biol Chem 1997; 272:11261-7. [PMID: 9111029 DOI: 10.1074/jbc.272.17.11261] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
A human liver microsomal beta-glucosidase has been purified to apparent homogeneity in sodium dodecyl sulfate-polyacrylamide gel electrophoresis where a single protein band of Mr 100,000 was obtained under reducing conditions. The enzyme was enriched about 73, 000-fold over starting microsomal membranes by polyethylene glycol fractionation, anion exchange chromatographies on DEAE-Trisacryl, and Mono Q followed by affinity chromatography on N-(9-carboxynonyl)-1-deoxynojirimycin-AH-Sepharose 4B. The purified enzyme had a pH optimum between 5.0 and 6.4, was activated by divalent metal ions, and required phospholipids for exhibition of activity. The enzyme catalyzed the hydrolysis of 3beta-D-glucosido-lithocholic and 3beta-D-glucosido-chenodeoxycholic acids with high affinity (Km, 1.7 and 6.2 microM, respectively) and of the beta-D-glucoside (Km, 210 microM) and the beta-D-galactoside of 4-methylumbelliferone. The ratio of relative reaction rates for these substrates was about 6:3:11:1. No activity was detectable toward 6beta-D-glucosido-hyodeoxycholic acid, glucocerebroside, and the following glycosides of 4-methylumbelliferone: alpha-D-glucoside, alpha-L-arabinoside, beta-D-fucoside or beta-D-xyloside. Immunoinhibition and immunoprecipitation studies using antibodies prepared against lysosomal glucocerebrosidase showed no cross-reactivity with microsomal beta-glucosidase suggesting that these two enzymes are antigenically unrelated.
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Affiliation(s)
- H Matern
- Department of Internal Medicine III, Aachen University of Technology, D-52074 Aachen, Federal Republic of Germany
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12
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Vaccaro AM, Tatti M, Ciaffoni F, Salvioli R, Maras B, Barca A. Function of saposin C in the reconstitution of glucosylceramidase by phosphatidylserine liposomes. FEBS Lett 1993; 336:159-62. [PMID: 8262201 DOI: 10.1016/0014-5793(93)81631-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The function of saposin C (Sap C), a glucosylceramidase activator protein, in the enzyme stimulation by phosphatidylserine (PS) liposomes has been investigated. Using gel filtration experiments evidence was obtained for Sap C binding to PS large unilamellar vesicles (LUV) but not to glucosylceramidase. PS LUV, which by themselves are unable to tightly bind and stimulate the enzyme, acquire the capacity to also bind the enzyme after interaction with Sap C, making it express its full activity. Our results indicate that the primary step in the Sap C mode of action resides in its association with PS membranes; in turn, this association promotes the interaction between the membranes and glucosylceramidase.
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Affiliation(s)
- A M Vaccaro
- Department of Metabolism and Pathological Biochemistry, Istituto Superiore Sanita, Roma, Italy
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van Weely S, van den Berg M, Barranger JA, Sa Miranda MC, Tager JM, Aerts JM. Role of pH in determining the cell-type-specific residual activity of glucocerebrosidase in type 1 Gaucher disease. J Clin Invest 1993; 91:1167-75. [PMID: 8450045 PMCID: PMC288073 DOI: 10.1172/jci116276] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The properties of control and 370Asn-->Ser glucocerebrosidase, the frequently encountered mutated form of the enzyme in type 1 Gaucher disease, were studied in vitro as well as in situ. The catalytic properties of purified 370Asn-->Ser glucocerebrosidase were highly dependent on the assay conditions. The enzyme was deficient in activity towards substrate and in reactivity with the irreversible inhibitor conduritol B-epoxide (CBE) when activated by the bile salt taurocholate. In the presence of more physiological activators, the lysosomal activator protein saposin C and phosphatidylserine, the 370Asn-->Ser enzyme was near normal in kinetic properties at pH values approximately 5, but not at higher pH. In intact fibroblasts, the enzymic activity of the 370Asn-->Ser glucocerebrosidase and its reactivity with CBE were found to be clearly deficient. However, in intact lymphoblasts from the same patients, the behavior of the mutant enzyme was near normal. The catalytic efficiency of 370Asn-->Ser glucocerebrosidase in situ was also found to be highly pH dependent. When intact lymphoblasts were cultured in the presence of permeant weak bases, which increase the pH of acidic intracellular compartments, the catalytic efficiency of the mutant enzyme, as assessed by its reactivity with CBE, became markedly impaired. Our findings indicate that the intralysosomal pH in the intact cell can be expected to have a critical influence on the activation state of 370Asn-->Ser glucocerebrosidase and its ability to hydrolyse substrate. This phenomenon may partly underly the marked heterogeneity in clinical manifestation of Gaucher disease among patients with this mutated form of glucocerebrosidase.
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Affiliation(s)
- S van Weely
- E. C. Slater Institute for Biochemical Research, University of Amsterdam, The Netherlands
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Aerts JM, Van Weely S, Boot R, Hollak CE, Tager JM. Pathogenesis of lysosomal storage disorders as illustrated by Gaucher disease. J Inherit Metab Dis 1993; 16:288-91. [PMID: 8411983 DOI: 10.1007/bf00710267] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- J M Aerts
- E.C. Slater Institute for Biochemical Research, University of Amsterdam, The Netherlands
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Vaccaro AM, Tatti M, Ciaffoni F, Salvioli R, Roncaioli P. Reconstitution of glucosylceramidase on binding to acidic phospholipid-containing vesicles. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1119:239-46. [PMID: 1547268 DOI: 10.1016/0167-4838(92)90208-u] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Studies were conducted to investigate the mechanism by which acidic phospholipid-containing vesicles stimulate purified placental glucosylceramidase activity towards the water-soluble substrate 4-methylumbelliferyl-beta-D-glucopyranoside (MUGlc). Vesicles composed of pure phosphatidic acid (PA) or pure phosphatidylserine (PS) stimulated the activity of the enzyme about 20-fold. The inclusion of cholesterol and phosphatidylcholine (PC), beside PA, into the vesicles slightly improved their stimulatory effect. Further addition of oleic acid (OA) markedly increased the stimulation (50-fold). By ultracentrifugation and gel permeation procedures it was shown that, under optimal conditions for stimulation of the MUGlc hydrolysis by acidic phospholipid-containing vesicles, purified glucosylceramidase spontaneously binds to their surface. Interestingly, the molar fraction of the acidic phospholipid into the mixed vesicles, rather than its concentration in the assay, is the crucial parameter for activation and binding of the enzyme. The importance of glucosylceramidase association with appropriate vesicles for enzyme activation was indicated by observing that the presence of 0.2 M citrate-phosphate buffer (pH 5.5), that prevented the binding to PA-containing surfaces, also inhibited the enzyme activity. Our results indicate that the reconstitution of glucosylceramidase activity occurs through the spontaneous tight association of the enzymatic protein with preformed acidic phospholipid-containing vesicles.
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Affiliation(s)
- A M Vaccaro
- Department of Metabolism and Pathological Biochemistry, Istituto Superiore Sanità, Roma, Italy
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Van Weely S, Van Leeuwen MB, Jansen ID, De Bruijn MA, Brouwer-Kelder EM, Schram AW, Sa Miranda MC, Barranger JA, Petersen EM, Goldblatt J. Clinical phenotype of Gaucher disease in relation to properties of mutant glucocerebrosidase in cultured fibroblasts. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1096:301-11. [PMID: 1829642 DOI: 10.1016/0925-4439(91)90066-i] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We have investigated several parameters of glucocerebrosidase in cultured skin fibroblasts from patients with various clinical phenotypes of Gaucher disease. In this study no strict correlation was found between the clinical manifestations of Gaucher disease and the parameters investigated in fibroblasts. These parameters included the specific activity of the enzyme in extracts towards natural lipid and artificial substrate in the presence of different activators; the enzymic activity per unit of glucocerebrosidase protein; the rate of synthesis of the enzyme and its stability; and the post-translational processing of the enzyme. In addition, the activity in situ of glucocerebrosidase in fibroblasts was investigated using a novel method by analysis of the catabolism of NBD-glucosylceramide in cells that were loaded with bovine serum albumin-lipid complexes. Again, no complete correlation with the clinical phenotype of patients was detectable. Glucocerebrosidase in fibroblasts from most non-neuronopathic (type 1) Gaucher disease patients differs in some aspects from enzyme in cells from patients with neurological forms (types 2 and 3). The stimulation by activator protein and phospholipid is clearly more pronounced in type 1 than in types 2 and 3; the enzymic activity per unit of glucocerebrosidase protein in type 1 is severely reduced in the presence of taurocholate and the amount of glucocerebrosidase appears (near) normal in contrast to the situation in types 2 and 3 Gaucher fibroblasts. However, this distinction was not always consistent; glucocerebrosidase in fibroblasts from some type 1 Gaucher patients, particularly some South African cases, was comparable in properties to enzyme in type 2 and 3 patients.
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Affiliation(s)
- S Van Weely
- E.C. Slater Institute for Biochemical Research, University of Amsterdam, The Netherlands
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Ohashi T, Hong CM, Weiler S, Tomich JM, Aerts JM, Tager JM, Barranger JA. Characterization of human glucocerebrosidase from different mutant alleles. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(19)67845-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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