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Torralba-Cabeza MÁ, Olivera-González S, Sierra-Monzón JL. The Importance of a Multidisciplinary Approach in the Management of a Patient with Type I Gaucher Disease. Diseases 2018; 6:diseases6030069. [PMID: 30049986 PMCID: PMC6164989 DOI: 10.3390/diseases6030069] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 07/20/2018] [Accepted: 07/23/2018] [Indexed: 01/17/2023] Open
Abstract
Managing the multisystemic symptoms of type I Gaucher Disease (GD) requires a multidisciplinary team approach that includes disease-specific treatments, as well as supportive care. This involves a range of medical specialists, general practitioners, supportive care providers, and patients. Phenotype classification and the setting of treatment goals are important for optimizing the management of type I GD, and for providing personalized care. The ability to classify disease severity using validated measurement tools allows the standardization of patient monitoring, and the measurement of disease progression and treatment response. Defining treatment goals is useful to provide a benchmark for assessing treatment response and managing the expectations of patients and their families. Although treatment goals will vary depending on disease severity, they include the stabilization, improvement or reversal (if possible) of clinical manifestations. Enzyme replacement therapy (ERT) is the standard care for patients with type I GD, but a novel substrate reduction therapy (SRT), Eliglustat, has demonstrated safety and efficacy in selected patients. To ensure that treatment goals are being achieved, regular and comprehensive follow up are necessary.
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Affiliation(s)
- Miguel-Ángel Torralba-Cabeza
- Aragon Health Research Institute (ISS Aragón), Department of Internal Medicine, Unit of Rare Disorders, "Lozano Blesa" University Hospital, 15th San Juan Bosco Avenue, 50009 Zaragoza, Spain.
| | - Susana Olivera-González
- Aragon Health Research Institute (ISS Aragón), Department of Internal Medicine, Unit of Rare Disorders, "Lozano Blesa" University Hospital, 15th San Juan Bosco Avenue, 50009 Zaragoza, Spain.
| | - José-Luis Sierra-Monzón
- Aragon Health Research Institute (ISS Aragón), Department of Internal Medicine, Unit of Rare Disorders, "Lozano Blesa" University Hospital, 15th San Juan Bosco Avenue, 50009 Zaragoza, Spain.
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2
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Ben Bdira F, Kallemeijn WW, Oussoren SV, Scheij S, Bleijlevens B, Florea BI, van Roomen CPAA, Ottenhoff R, van Kooten MJFM, Walvoort MTC, Witte MD, Boot RG, Ubbink M, Overkleeft HS, Aerts JMFG. Stabilization of Glucocerebrosidase by Active Site Occupancy. ACS Chem Biol 2017; 12:1830-1841. [PMID: 28485919 PMCID: PMC5525105 DOI: 10.1021/acschembio.7b00276] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
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Glucocerebrosidase
(GBA) is a lysosomal β-glucosidase that
degrades glucosylceramide. Its deficiency results in Gaucher disease
(GD). We examined the effects of active site occupancy of GBA on its
structural stability. For this, we made use of cyclophellitol-derived
activity-based probes (ABPs) that bind irreversibly to the catalytic
nucleophile (E340), and for comparison, we used the potent reversible
inhibitor isofagomine. We demonstrate that cyclophellitol ABPs improve
the stability of GBA in vitro, as revealed by thermodynamic
measurements (Tm increase by 21 °C),
and introduce resistance to tryptic digestion. The stabilizing effect
of cell-permeable cyclophellitol ABPs is also observed in intact cultured
cells containing wild-type GBA, N370S GBA (labile in lysosomes), and
L444P GBA (exhibits impaired ER folding): all show marked increases
in lysosomal forms of GBA molecules upon exposure to ABPs. The same
stabilization effect is observed for endogenous GBA in the liver of
wild-type mice injected with cyclophellitol ABPs. Stabilization effects
similar to those observed with ABPs were also noted at high concentrations
of the reversible inhibitor isofagomine. In conclusion, we provide
evidence that the increase in cellular levels of GBA by ABPs and by
the reversible inhibitor is in part caused by their ability to stabilize
GBA folding, which increases the resistance of GBA against breakdown
by lysosomal proteases. These effects are more pronounced in the case
of the amphiphilic ABPs, presumably due to their high lipophilic potential,
which may promote further structural compactness of GBA through hydrophobic
interactions. Our study provides further rationale for the design
of chaperones for GBA to ameliorate Gaucher disease.
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Affiliation(s)
| | | | | | - Saskia Scheij
- Department
of Medical Biochemistry Academic Medical Center, University of Amsterdam, Amsterdam 1105 AZ, The Netherlands
| | - Boris Bleijlevens
- Department
of Medical Biochemistry Academic Medical Center, University of Amsterdam, Amsterdam 1105 AZ, The Netherlands
| | | | - Cindy P. A. A. van Roomen
- Department
of Medical Biochemistry Academic Medical Center, University of Amsterdam, Amsterdam 1105 AZ, The Netherlands
| | - Roelof Ottenhoff
- Department
of Medical Biochemistry Academic Medical Center, University of Amsterdam, Amsterdam 1105 AZ, The Netherlands
| | | | | | | | | | | | | | - Johannes M. F. G. Aerts
- Department
of Medical Biochemistry Academic Medical Center, University of Amsterdam, Amsterdam 1105 AZ, The Netherlands
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3
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Torralba MA, Olivera S, Bureo JC, Dalmau J, Nuñez R, León P, Villarrubia J. Residual enzymatic activity as a prognostic factor in patients with Gaucher disease type 1: correlation with Zimran and GAUSS-I index and the severity of bone disease. QJM 2016; 109:449-52. [PMID: 26792850 DOI: 10.1093/qjmed/hcw002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Gaucher disease (GD) is an autosomal recessive disorder produced by mutations in the glucocerebrosidase gene (GBA), causing storage of glucosylceramide in reticuloendothelial cells in multiple organs. Traditionally, the prediction of the phenotype based on the genotype has been reported to be limited. SUBJECTS AND METHODS We investigated the correlation between the enzymatic residual activity (ERA) and the phenotype at diagnosis of the disease in 45 GD Spanish patients (44 with type I and 1 with type III GD). The genotype involved two of the following previously expressed proteins: c.517A > C (T134P), 1%; c.721G > A (G202R), 17%; c.1090G > T (G325W), 13.9%; c.1208G > A (S364N), 4.1%; c.1226A > G (N370S), 17.8%; c.1246G > A (G377S), 17.6%; c.1289C > T (P391L), 8.5%; c.1448T > C (L444P), 3%; and c.1504C > T (R463C), 24.5%. Recombinant alleles, deletion of 55 bp in exon 9 and 84GG mutation were considered as mutations with no residual enzymatic activity. RESULTS The ERA showed a statistically significant correlation with chitotriosidase (P < 0.001), age (P < 0.001), spleen size (P < 0.001), 'Zimran's Severity Score Index' (P < 0.01) and the 'Gaucher Disease Severity Score Index-Type I' (P < 0.0001) at diagnosis of the disorder. Previous to any medical intervention, a comparison between the ERA and bone involvement, demonstrated a statistically significant relationship (P < 0.01) between the two variables. CONCLUSIONS This study data allowed us to define a new criterion for prognostic assessment of the disease at diagnosis, called Protein Severity Index, which expresses the theoretical severity of the genotype presented by patients, according to the corresponding ERA.
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Affiliation(s)
- M A Torralba
- From the Department of Internal Medicine, "Lozano Blesa" University Hospital, Zaragoza, Spain,
| | - S Olivera
- From the Department of Internal Medicine, "Lozano Blesa" University Hospital, Zaragoza, Spain
| | - J C Bureo
- Department of Internal Medicine, "Infanta Cristina" University Hospital, Badajoz, Spain
| | - J Dalmau
- Department of Pediatrics, "La Fé" University Hospital, Valencia, Spain
| | - R Nuñez
- Department of Hematology, "Virgen Del Rocío" University Hospital, Sevilla, Spain
| | - P León
- Department of Hematology, "Dr Peset" University Hospital, Valencia, Spain and
| | - J Villarrubia
- Department of Hematology, "Ramón Y Cajal" University Hospital, Madrid, Spain
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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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Characterization of the complex formed by β-glucocerebrosidase and the lysosomal integral membrane protein type-2. Proc Natl Acad Sci U S A 2016; 113:3791-6. [PMID: 27001828 DOI: 10.1073/pnas.1514005113] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The lysosomal integral membrane protein type-2 (LIMP-2) plays a pivotal role in the delivery of β-glucocerebrosidase (GC) to lysosomes. Mutations in GC result in Gaucher's disease (GD) and are the major genetic risk factor for the development of Parkinson's disease (PD). Variants in the LIMP-2 gene cause action myoclonus-renal failure syndrome and also have been linked to PD. Given the importance of GC and LIMP-2 in disease pathogenesis, we studied their interaction sites in more detail. Our previous data demonstrated that the crystal structure of LIMP-2 displays a hydrophobic three-helix bundle composed of helices 4, 5, and 7, of which helix 5 and 7 are important for ligand binding. Here, we identified a similar helical motif in GC through surface potential analysis. Coimmunoprecipitation and immunofluorescence studies revealed a triple-helical interface region within GC as critical for LIMP-2 binding and lysosomal transport. Based on these findings, we generated a LIMP-2 helix 5-derived peptide that precipitated and activated recombinant wild-type and GD-associated N370S mutant GC in vitro. The helix 5 peptide fused to a cell-penetrating peptide also activated endogenous lysosomal GC and reduced α-synuclein levels, suggesting that LIMP-2-derived peptides can be used to activate endogenous as well as recombinant wild-type or mutant GC efficiently. Our data also provide a structural model of the LIMP-2/GC complex that will facilitate the development of GC chaperones and activators as potential therapeutics for GD, PD, and related synucleinopathies.
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6
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Panicker LM, Miller D, Awad O, Bose V, Lun Y, Park TS, Zambidis ET, Sgambato JA, Feldman RA. Gaucher iPSC-derived macrophages produce elevated levels of inflammatory mediators and serve as a new platform for therapeutic development. Stem Cells 2015; 32:2338-49. [PMID: 24801745 DOI: 10.1002/stem.1732] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 04/09/2014] [Indexed: 12/21/2022]
Abstract
Gaucher disease (GD) is an autosomal recessive disorder caused by mutations in the acid β-glucocerebrosidase (GCase; GBA) gene. The hallmark of GD is the presence of lipid-laden Gaucher macrophages, which infiltrate bone marrow and other organs. These pathological macrophages are believed to be the sources of elevated levels of inflammatory mediators present in the serum of GD patients. The alteration in the immune environment caused by GD is believed to play a role in the increased risk of developing multiple myeloma and other malignancies in GD patients. To determine directly whether Gaucher macrophages are abnormally activated and whether their functional defects can be reversed by pharmacological intervention, we generated GD macrophages by directed differentiation of human induced pluripotent stem cells (hiPSC) derived from patients with types 1, 2, and 3 GD. GD hiPSC-derived macrophages expressed higher levels of tumor necrosis factor α, IL-6, and IL-1β than control cells, and this phenotype was exacerbated by treatment with lipopolysaccharide. In addition, GD hiPSC macrophages exhibited a striking delay in clearance of phagocytosed red blood cells, recapitulating the presence of red blood cell remnants in Gaucher macrophages from bone marrow aspirates. Incubation of GD hiPSC macrophages with recombinant GCase, or with the chaperones isofagomine and ambroxol, corrected the abnormal phenotypes of GD macrophages to an extent that reflected their known clinical efficacies. We conclude that Gaucher macrophages are the likely source of the elevated levels of inflammatory mediators in the serum of GD patients and that GD hiPSC are valuable new tools for studying disease mechanisms and drug discovery.
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Affiliation(s)
- Leelamma M Panicker
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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7
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Babajani G, Tropak MB, Mahuran DJ, Kermode AR. Pharmacological chaperones facilitate the post-ER transport of recombinant N370S mutant β-glucocerebrosidase in plant cells: evidence that N370S is a folding mutant. Mol Genet Metab 2012; 106:323-9. [PMID: 22592100 PMCID: PMC3425598 DOI: 10.1016/j.ymgme.2012.04.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2012] [Revised: 04/20/2012] [Accepted: 04/20/2012] [Indexed: 12/22/2022]
Abstract
Gaucher disease is a prevalent lysosomal storage disease in which affected individuals inherit mutations in the gene (GBA1) encoding lysosomal acid β-glucosidase (glucocerebrosidase, GCase, EC 3.2.1.45). One of the most prevalent disease-causing mutations in humans is a N370S missense mutation in the GCase protein. As part of a larger endeavor to study the fate of mutant human proteins expressed in plant cells, the N370S mutant protein along with the wild-type- (WT)-GCase, both equipped with a signal peptide, were synthesized in transgenic tobacco BY2 cells, which do not possess lysosomes. The enzymatic activity of plant-recombinant N370S GCase lines was significantly lower (by 81-95%) than that of the WT-GCase lines. In contrast to the WT-GCase protein, which was efficiently secreted from tobacco BY2 cells, and detected in large amounts in the culture medium, only a small proportion of the N370S GCase was secreted. Pharmacological chaperones such as N-(n-nonyl) deoxynojirimycin and ambroxol increased the steady-state mutant protein levels both inside the plant cells and in the culture medium. These findings contradict the assertion that small molecule chaperones increase N370S GCase activity (as assayed in treated patient cell lysates) by stabilizing the enzyme in the lysosome, and suggest that the mutant protein is impaired in its ability to obtain its functional folded conformation, which is a requirement for exiting the lumen of the ER.
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Affiliation(s)
- Gholamreza Babajani
- Department of Biological Sciences, Simon Fraser University, 8888 University Dr., Burnaby, BC, Canada V5A 1S6
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8
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Decroocq C, Rodríguez-Lucena D, Ikeda K, Asano N, Compain P. Cyclodextrin-Based Iminosugar Click Clusters: The First Examples of Multivalent Pharmacological Chaperones for the Treatment of Lysosomal Storage Disorders. Chembiochem 2012; 13:661-4. [DOI: 10.1002/cbic.201200005] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Indexed: 12/31/2022]
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9
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Wei RR, Hughes H, Boucher S, Bird JJ, Guziewicz N, Van Patten SM, Qiu H, Pan CQ, Edmunds T. X-ray and biochemical analysis of N370S mutant human acid β-glucosidase. J Biol Chem 2010; 286:299-308. [PMID: 20980263 DOI: 10.1074/jbc.m110.150433] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Gaucher disease is caused by mutations in the enzyme acid β-glucosidase (GCase), the most common of which is the substitution of serine for asparagine at residue 370 (N370S). To characterize the nature of this mutation, we expressed human N370S GCase in insect cells and compared the x-ray structure and biochemical properties of the purified protein with that of the recombinant human GCase (imiglucerase, Cerezyme®). The x-ray structure of N370S mutant acid β-glucosidase at acidic and neutral pH values indicates that the overall folding of the N370S mutant is identical to that of recombinant GCase. Subtle differences were observed in the conformation of a flexible loop at the active site and in the hydrogen bonding ability of aromatic residues on this loop with residue 370 and the catalytic residues Glu-235 and Glu-340. Circular dichroism spectroscopy showed a pH-dependent change in the environment of tryptophan residues in imiglucerase that is absent in N370S GCase. The mutant protein was catalytically deficient with reduced V(max) and increased K(m) values for the substrate p-nitrophenyl-β-D-glucopyranoside and reduced sensitivity to competitive inhibitors. N370S GCase was more stable to thermal denaturation and had an increased lysosomal half-life compared with imiglucerase following uptake into macrophages. The competitive inhibitor N-(n-nonyl)deoxynojirimycin increased lysosomal levels of both N370S and imiglucerase 2-3-fold by reducing lysosomal degradation. Overall, these data indicate that the N370S mutation results in a normally folded but less flexible protein with reduced catalytic activity compared with imiglucerase.
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Affiliation(s)
- Ronnie R Wei
- Genzyme Corp., Framingham, Massachusetts 01701, USA.
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10
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van den Broek LAGM, Vermaas DJ, Heskamp BM, van Boeckel CAA, Tan MCAA, Bolscher JGM, Ploegh HL, van Kemenade FJ, de Goede REY, Miedema F. Chemical modification of azasugars, inhibitors of N-glycoprotein-processing glycosidases and of HIV-I infection: Review and structure-activity relationships. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/recl.19931120204] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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11
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Liou B, Grabowski GA. Participation of asparagine 370 and glutamine 235 in the catalysis by acid beta-glucosidase: the enzyme deficient in Gaucher disease. Mol Genet Metab 2009; 97:65-74. [PMID: 19217815 PMCID: PMC2699545 DOI: 10.1016/j.ymgme.2009.01.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Accepted: 01/07/2009] [Indexed: 11/26/2022]
Abstract
The hydrolysis of glucosylceramide by acid beta-glucosidase proceeds via a two-step, double displacement mechanism that includes cleavage of the O-beta-glucosidic bond, enzyme-glucosylation and, then, enzyme-deglucosylation. Two residues that may impact this cycle are N370 and E235. The N370S mutant enzyme is very common in Gaucher disease type 1 patients. Homology and crystal data predictions suggested that E235 is the acid/base catalyst in the hydrolytic reaction. Here, the roles of N370 and E235 in hydrolysis were explored using mutant proteins with selected amino acid substitutions. Heterologously expressed enzymes were characterized using inhibitors, activators, and alternative substrates to gain insight into the effects on the glucosylation (single turnover) and deglucosylation (transglucosylation) steps in catalysis. Specific substitutions at N370 selectively altered only the glucosylation step whereas N370S altered this and the deglucosylation steps. To provide functional data to support E235 as the acid/base catalyst, progress curves with poor substrates with more acidic leaving groups were used in the presence and absence of azide as an exogenous nucleophile. The restoration of E235G activity to nearly wild-type levels was achieved using azide with 2,4-dinitrophenyl-beta-glucoside as substrate. The loss of the acidic arm of the pH optimum activity curve of E235G provided additional functional support for E235 as the acid/base in catalysis. This study provides insight into the function of these residues in acid beta-glucosidase active site function.
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Affiliation(s)
- Benjamin Liou
- The Children’s Hospital Research Foundation of Cincinnati Children’s Hospital Medical Center, Division and Program in Human Genetics, 3333 Burnet Avenue, ML 4006, Cincinnati, OH 45229-3039
| | - Gregory A. Grabowski
- The Children’s Hospital Research Foundation of Cincinnati Children’s Hospital Medical Center, Division and Program in Human Genetics, 3333 Burnet Avenue, ML 4006, Cincinnati, OH 45229-3039
- Department of Pediatrics, University of Cincinnati, Cincinnati, Ohio
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12
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Kacher Y, Brumshtein B, Boldin-Adamsky S, Toker L, Shainskaya A, Silman I, Sussman JL, Futerman AH. Acid beta-glucosidase: insights from structural analysis and relevance to Gaucher disease therapy. Biol Chem 2008; 389:1361-9. [PMID: 18783340 DOI: 10.1515/bc.2008.163] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In mammalian cells, glucosylceramide (GlcCer), the simplest glycosphingolipid, is hydrolyzed by the lysosomal enzyme acid beta-glucosidase (GlcCerase). In the human metabolic disorder Gaucher disease, GlcCerase activity is significantly decreased owing to one of approximately 200 mutations in the GlcCerase gene. The most common therapy for Gaucher disease is enzyme replacement therapy (ERT), in which patients are given intravenous injections of recombinant human GlcCerase; the Genzyme product Cerezyme has been used clinically for more than 15 years and is administered to approximately 4000 patients worldwide. Here we review the crystal structure of Cerezyme and other recombinant forms of GlcCerase, as well as of their complexes with covalent and non-covalent inhibitors. We also discuss the stability of Cerezyme, which can be altered by modification of its N-glycan chains with possible implications for improved ERT in Gaucher disease.
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Affiliation(s)
- Yaacov Kacher
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
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13
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Abstract
BACKGROUND The therapy of the lysosomal storage diseases (LSDs) was developed by supplying adequate amounts of the needed enzyme to affected individuals. This approach in Gaucher disease provided a prototype for the basic and clinical sciences, and the economic foundation for other ultra-orphan diseases. OBJECTIVE Using the success of enzyme therapy for Gaucher disease, the challenges are highlighted for alternative bioproduction systems, and substrate reduction and molecular chaperone approaches for treatment of Gaucher disease and other ultra-orphan diseases. METHODS Literature review provided insight into the current status of enzyme therapies for LSDs, the proposed mechanisms of alternative approaches to therapy, and the obstacles in a competitive marketplace for treatment of ultra-rare diseases. RESULTS/CONCLUSIONS These developments are placed in the contexts of finding rare patients with LSDs, their marked phenotypic spectrum, potential markets, and new orphan drug costs. The confluence of these challenges has led to a competitive environment with the potential for multiple, alternative, expensive treatments for orphan diseases.
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Affiliation(s)
- Gregory A Grabowski
- University of Cincinnati College of Medicine, Cincinnati Children's Hospital Medical Center, The Division of Human Genetics, Department of Pediatrics, Cincinnati, Ohio 45229-3039, USA.
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14
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Steet RA, Chung S, Wustman B, Powe A, Do H, Kornfeld SA. The iminosugar isofagomine increases the activity of N370S mutant acid beta-glucosidase in Gaucher fibroblasts by several mechanisms. Proc Natl Acad Sci U S A 2006; 103:13813-8. [PMID: 16945909 PMCID: PMC1564243 DOI: 10.1073/pnas.0605928103] [Citation(s) in RCA: 179] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Gaucher disease is a lysosomal storage disorder caused by deficiency in lysosomal acid beta-glucosidase (GlcCerase), the enzyme responsible for the catabolism of glucosylceramide. One of the most prevalent disease-causing mutations, N370S, results in an enzyme with lower catalytic activity and impaired exit from the endoplasmic reticulum. Here, we report that the iminosugar isofagomine (IFG), an active-site inhibitor, increases GlcCerase activity 3.0 +/- 0.6-fold in N370S fibroblasts by several mechanisms. A major effect of IFG is to facilitate the folding and transport of newly synthesized GlcCerase in the endoplasmic reticulum, thereby increasing the lysosomal pool of the enzyme. In addition, N370S GlcCerase synthesized in the presence of IFG exhibits a shift in pH optimum from 6.4 to 5.2 and altered sensitivity to SDS. Although IFG fully inhibits GlcCerase in the lysosome in an in situ assay, washout of the drug leads to partial recovery of GlcCerase activity within 4 h and full recovery by 24 h. These findings provide support for the possible use of active-site inhibitors in the treatment of some forms of Gaucher disease.
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Affiliation(s)
- Richard A. Steet
- *Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110; and
| | - Stephen Chung
- *Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110; and
| | - Brandon Wustman
- Amicus Therapeutics, 6 Cedar Brook Drive, Cranbury, NJ 08512
| | - Allan Powe
- Amicus Therapeutics, 6 Cedar Brook Drive, Cranbury, NJ 08512
| | - Hung Do
- Amicus Therapeutics, 6 Cedar Brook Drive, Cranbury, NJ 08512
| | - Stuart A. Kornfeld
- *Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110; and
- To whom correspondence should be addressed. E-mail:
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Sinclair G, Pfeifer TA, Grigliatti TA, Choy FYM. Secretion of human glucocerebrosidase from stable transformed insect cells using native signal sequences. Biochem Cell Biol 2006; 84:148-56. [PMID: 16609695 DOI: 10.1139/o05-165] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The lysosomal hydrolase, glucocerebrosidase (GBA), catalyses the penultimate step in the breakdown of membrane glycosphingolipids. An inherited deficiency of this enzyme activity leads to the onset of Gaucher disease, the most common lysosomal storage disorder. Affected individuals range from adults with hepatosplenomegaly, haematological complications, and bone pain (type 1 disease) to children and neonates with severe neuronopathy leading to neurological degradation and premature death (type 2 and type 3 disease). Enzyme replacement therapy has become the standard of treatment for type I Gaucher disease but remains an expensive option, in part because of the cost of recombinant enzyme production using mammalian cell culture. Using a nonlytic integrative plasmid expression system, we have successfully produced active human GBA in stable transformed Sf9 (Spodoptera frugiperda) cells. Both the 39 and 19 amino acid native GBA signal sequences were capable of endoplasmic reticulum targeting, which led to secretion of the recombinant protein, although approximately 30% more enzyme was produced using the longer signal sequence. The secreted product was purified to apparent electrophoretic homogeneity using hydrophobic interaction chromatography and found to be produced in a fully glycosylated and a hypoglycosylated form, both of which cross-reacted with a human GBA-specific monoclonal antibody. The pH optimum (at pH 5.5) for activity of the recombinant enzyme was as expected for human GBA using the artificial substrate 4-methyl-umbelliferyl-β-D-glycopyranoside. With initial nonoptimized expression levels estimated at 10–15 mg/L using small-scale batch cultures, stable transformed insect cells could provide a viable alternative system for the heterologous production of human GBA when grown under optimized perfusion culture conditions.Key words: Gaucher disease, glucocerebrosidase, protein expression, enzyme purification, Sf9 cells.
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Affiliation(s)
- Graham Sinclair
- Biomedical Research Centre, Department of Biology, University of Victoria, Station CSC, Canada
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16
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Alfonso P, Pampín S, Estrada J, Rodríguez-Rey JC, Giraldo P, Sancho J, Pocoví M. Miglustat (NB-DNJ) works as a chaperone for mutated acid beta-glucosidase in cells transfected with several Gaucher disease mutations. Blood Cells Mol Dis 2006; 35:268-76. [PMID: 16039881 DOI: 10.1016/j.bcmd.2005.05.007] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2005] [Revised: 05/17/2005] [Accepted: 05/17/2005] [Indexed: 11/29/2022]
Abstract
Gaucher disease (GD) is a disorder of glycosphinglipid metabolism caused by deficiency of lysosomal acid beta-glucosidase (GC), resulting in progressive deposition of glucosylceramide in macrophages. The glucose analogue, N-butyl-deoxynojirimycin (NB-DNJ, Miglustat), is an inhibitor of the ceramide-specific glucosyltransferase (CSG) which catalyzes the first step of glycosphingolipids biosynthesis and is currently approved for the oral treatment of type 1 GD. Using site-directed mutagenesis, we constructed plasmids containing wild-type and several mutations in glucocerebrosidase (GBA) gene. The plasmids were transfected into COS-7 cells and stable transfected cell lines were obtained by geneticin (G418) selection. Cells were cultured during 6 days with medium with or without 10 microM NB-DNJ. The addition of NB-DNJ to COS-7 cell medium leads to 1.3-, 2.1-, 2.3-, 3.6-, and 9.9-fold increase in the activity of S364R, wild-type, N370S, V15M, and M123T GC, respectively. However, no significant changes were observed in the activity of the L444P, L336P, and S465del mutated proteins, but a small decrease in the rare P266L variant was observed. These results suggest that NB-DNJ, in addition to the inhibitory effect on CSG, also works as a "chemical chaperone", increasing the activity of acid beta-glucosidase of wild-type and several GC mutated proteins, including the most frequent N370S mutation. The specific location of the Miglustat binding site in GC is unknown. Potential binding sites in the enzyme have been searched for using computational molecular docking. The searching strategy identified three potential GC binding sites for Miglustat, one being the substrate-binding site of the enzyme, which was the best-ranked site by AutoDock program. Therefore, it is possible that Miglustat exerts its chaperoning activity on acid beta-glucosidase by acting as an inhibitor bound at the active site. This increase on the activity of the acid beta-glucosidase would imply that Miglustat is not only a substrate reducer but also an inhibitor of the GC degradation, with very promising clinical implications for the treatment of GD patients.
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Affiliation(s)
- Pilar Alfonso
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Plaza San Francisco s/n, 50009 Zaragoza, Spain
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17
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Liou B, Kazimierczuk A, Zhang M, Scott CR, Hegde RS, Grabowski GA. Analyses of variant acid beta-glucosidases: effects of Gaucher disease mutations. J Biol Chem 2005; 281:4242-53. [PMID: 16293621 DOI: 10.1074/jbc.m511110200] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Acid beta-glucosidase (GCase) is a 497-amino acid, membrane-associated lysosomal exo-beta-glucosidase whose defective activity leads to the Gaucher disease phenotypes. To move toward a structure/function map for disease mutations, 52 selected single amino acid substitutions were introduced into GCase, expressed in an insect cell system, purified, and characterized for basic kinetic, stability, and activator response properties. The variant GCases from Gaucher disease patients and selected variant GCases from the mouse had decreased relative k(cat) and differential effects on active site binding and/or attachment of mechanism-based covalent (conduritol B epoxide) or reversible (deoxynojirimycin derivatives) inhibitors. A defect in negatively charged phospholipid activation was present in the majority of variant GCases but was increased in two, N370S and V394L. Deficits in saposin C enhancement of k(cat) were present in variant GCases involving residues 48-122, whereas approximately 2-fold increases were obtained with the L264I GCase. About 50% of variant GCases each had wild-type or increased sensitivity to in vitro cathepsin D digestion. Mapping of these properties onto the crystal structures of GCase indicated wide dispersion of functional properties that can affect catalytic function and stability. Site-directed mutagenesis of cysteine residues showed that the disulfide bonds, Cys(4)-Cys(16) and Cys(18)-Cys(23), and a free Cys(342) were essential for activity; the free Cys(126) and Cys(248) were not. Relative k(cat) was highly sensitive to a His substitution at Arg(496) but not at Arg(495). These studies and high phylogenetic conservation indicate localized and general structural effects of Gaucher disease mutations that were not obvious from the nature of the amino acid substitution, including those predicted to be nondisruptive (e.g. Val --> Leu). These results provide initial studies for the engineering of variant GCases and, potentially, molecular chaperones for therapeutic use.
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Affiliation(s)
- Benjamin Liou
- Division and Program in Human Genetics, Children's Hospital Research Foundation, Cincinnati, OH 45229, USA
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18
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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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19
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Montfort M, Chabás A, Vilageliu L, Grinberg D. Functional analysis of 13 GBA mutant alleles identified in Gaucher disease patients: Pathogenic changes and "modifier" polymorphisms. Hum Mutat 2004; 23:567-75. [PMID: 15146461 DOI: 10.1002/humu.20043] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Gaucher disease, the most prevalent sphingolipidosis, is caused by the deficient activity of acid beta-glucosidase, mainly due to mutations in the GBA gene. Over 200 mutations have been identified worldwide, more than 25 of which were in Spanish patients. In order to demonstrate causality for Gaucher disease, some of them: c.662C>T (p.P182L), c.680A>G (p.N188S), c.886C>T (p.R257X), c.1054T>C (p.Y313H), c.1093G>A (p.E326K), c.1289C>T (p.P391L), c.1292A>T (p.N392I), c.1322T>C (p.I402T), and the double mutants [c.680A>G; c.1093G>A] ([p.N188S; p.E326K]) and [c.1448T>C; c.1093G>A] ([p.L444P; p.E326K]), were expressed in Sf9 cells using a baculovirus expression system. Other well-established Gaucher disease mutations, namely c.1226A>G (p.N370S), c.1342G>C (p.D409H), and c.1448T>C (p.L444P), were also expressed for comparison. The levels of residual acid beta-glucosidase activity of the mutant enzymes produced by the cDNAs carrying alleles c.662C>T (p.P182L), c.886C>T (p.R257X), c.1054T>C (p.Y313H), c.1289C>T (p.P391L), and c.1292A>T (p.N392I) were negligible. The c.1226A>G (p.N370S), c.1322T>C (p.I402T), c.1342G>C (p.D409H), c.1448T>C (p.L444P), and [c.1448T>C; c.1093G>A] ([p.L444P; p.E326K]) alleles produced enzymes with levels ranging from 6 to 14% of the wild-type. The three remaining alleles, c.680A>G (p.N188S), c.1093G>A (p.E326K), and [c.680A>G; c.1093G>A] ([p.N188S; p.E326K]), showed higher activity (66.6, 42.7, and 23.2%, respectively). Expression studies revealed that the c.1093G>A (p.E326K) change, which was never found alone in a Gaucher disease-causing allele, when found in a double mutant such as [c.680A>G; c.1093G>A] ([p.N188S; p.E326K]) and [c.1448T>C; c.1093G>A] ([p.L444P; p.E326K]), decreases activity compared to the activity found for the other mutation alone. These results suggest that c.1093G>A (p.E326K) should be considered a "modifier variant" rather than a neutral polymorphism, as previously considered. Mutation c.680A>G (p.N188S), which produces a mutant enzyme with the highest level of activity, is probably a very mild mutation or another "modifier variant."
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Affiliation(s)
- Magda Montfort
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
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20
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Sun Y, Qi X, Grabowski GA. Saposin C is required for normal resistance of acid beta-glucosidase to proteolytic degradation. J Biol Chem 2003; 278:31918-23. [PMID: 12813057 DOI: 10.1074/jbc.m302752200] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Saposins (A, B, C, and D) are small sphingolipid activator proteins that are derived by proteolytic processing of a common precursor, prosaposin. In the lysosomal sphingolipid degradation pathway, acid beta-glucosidase (GCase) requires saposin C for optimal in vitro and in vivo hydrolysis of glucocerebroside. The deficiency of prosaposin/saposins (PS-/-) in humans and mice leads to a decrease of GCase activity in selected tissues. Concordant decreases (>50%) of GCase protein and in vitro activity were detected in extracts of cultured fibroblasts and hepatocytes from PS-/- mice and human prosaposin-deficient fibroblasts. GCase RNA in the PS-/- cells was at wild-type levels. Compared with that in wild-type cells (t(1/2) >24 h), the GCase protein in the PS-/- cells had a faster disappearance rate (t(1/2) approximately 1 h in mouse and approximately 8 h in human) as determined by metabolic labeling and immunoprecipitation with anti-GCase antibodies. Treatment of PS-/- cells with leupeptin, an inhibitor of cysteine proteases, led to significant increases (approximately 2-fold) in GCase protein and in vitro activity. Loading saposin C to human PS-/- fibroblasts resulted in an enhancement of GCase protein and in vitro activity. Saposin D loading had no effect. These data indicate that saposin C is required for GCase resistance to proteolytic degradation in the cell. Thus, diminished in vivo GCase activity would be greater than expected only from the lack of GCase activation by saposin C. These results indicate a new property for saposin C, an anti-proteolytic protective function toward GCase.
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Affiliation(s)
- Ying Sun
- Division and Program in Human Genetics, Children's Hospital Research Foundation, Cincinnati, Ohio 45229-3039, USA
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21
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Stano J, Kovács P, Micieta K, Neubert K, Tintemann H, Korenová M. Localization and measurement of extracellular plant galactosidases. Acta Histochem 2003; 104:441-4. [PMID: 12553718 DOI: 10.1078/0065-1281-00665] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A simple, rapid and sensitive procedure for the identification and determination of plant extracellular alpha-galactosidase and beta-galactosidase is described using callus cultures and seedlings from tomato. Synthetic substrates (1-naphthyl- and p-nitrophenyl-alpha-D- and beta-D-galactopyranosides) were used for the identification and determination of intracellular and extracellular activity of alpha-galactosidase and beta-galactosidase, respectively. Many iminosugars or azasugars are strong glycosidase inhibitors and some of them show promising chemotherapeutic effects against viral diseases, and are potentially antidiabetic agents, as well as antitumor agents. These facts initiated our interest in a rapid and sensitive assay to determine activity of alpha-galactosidase and beta-galactosidase in plant tissues. The results presented here show the potential of the assay of the activity of intracellular and extracellular galactosidases of plant origin in inhibitory and/or biotechnological studies.
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Affiliation(s)
- Ján Stano
- Garden of Medicinal Plants, Faculty of Pharmacy, Bratislava, Slovak Republic.
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22
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Balbaa M, Mansour H, El-Sawy H, El-Ashry ESH. Inhibition of some hepatic glycosidases by the diseco nucleoside, 4-amino-3-(D-glucopentitol-1-yl)-5-mercapto-1,2,4-triazole and its 3-methyl analog. NUCLEOSIDES, NUCLEOTIDES & NUCLEIC ACIDS 2002; 21:695-708. [PMID: 12502284 DOI: 10.1081/ncn-120015726] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The in vivo and in vitro effects of 4-amino-3-(D-glucopentitol-1-yl)-5-mercapto-1,2,4-triazole and its 3-methyl analogue on alpha- and beta-glucosidases, beta-glucuronidase as well as alpha-amylase have been investigated. alpha-Glucosidase is the enzyme that is markedly affected in vivo and in vitro in a dose-dependent manner. The compounds showed a reversible inhibition of a competitive type for alpha-glucosidase. Moreover, they exert a relatively potent inhibition on alpha-glucosidase with a Ki magnitude of 3.6 x 10(-4), 9.5 x 10(-5) M.
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Affiliation(s)
- Mahmoud Balbaa
- Department of Biochemistry, Faculty of Science, Alexandria University, Alexandria, Egypt
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23
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Sinclair G, Choy FY, Ferreira P. Heterologous expression and characterization of a rare Gaucher disease mutation (c.481C > T) from a Canadian aboriginal population using archival tissue samples. Mol Genet Metab 2001; 74:345-52. [PMID: 11708865 DOI: 10.1006/mgme.2001.3215] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Gaucher disease is an inherited sphingolipidosis resulting from deleterious mutations in the glucocerebrosidase gene. Through direct sequence analysis of genomic DNA from whole blood, fibroblast cultures, and formalin-fixed archival tissue samples, we have identified a rare homozygous C > T transition at cDNA nucleotide 481 of the glucocerebrosidase gene that results in a proline to serine amino acid substitution (p.P122S) in an aboriginal family of Cree descent in northern Alberta, Canada. A 13-month-old boy (JB) presented with severe visceral Gaucher disease and was treated with enzyme replacement. Currently, at 11 years he is developmentally delayed, with oculomotor apraxia. A cousin (MS) had previously died at age 7 from complications of severe Gaucher disease, before enzyme replacement therapy was available. She was also developmentally delayed. Heterologous expression of this allele using a baculovirus expression system revealed 19.2% of normal enzyme activity on the artificial substrate 4-methylumbelliferyl beta-d-glucopyranoside (4MUGP). Genotype/phenotype correlation is complicated by incomplete clinical details, enzyme replacement therapy, and the difficulty in excluding other genetic and environmental causes of developmental delay. However the development of oculomotor apraxia in JB suggests a Type 3 Gaucher phenotype. The only previous report of this mutation was also from a member of the Cree Nation, who has had a rather similar clinical course. A protocol is described for the isolation of genomic DNA from formalin-fixed bone marrow aspirate archival specimens obtained from the deceased for subsequent PCR-based sequence analysis and mutation detection. This technique will be applicable to the screening of this and other populations for the frequency of known Gaucher mutations where traditional DNA sources are unavailable.
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Affiliation(s)
- G Sinclair
- Department of Biology, Centre for Environmental Health, University of Victoria, Victoria, British Columbia, Canada
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24
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Qi X, Grabowski GA. Molecular and cell biology of acid beta-glucosidase and prosaposin. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2001; 66:203-39. [PMID: 11051765 DOI: 10.1016/s0079-6603(00)66030-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- X Qi
- Children's Hospital Research Foundation, Cincinnati, Ohio 45229-3039, USA
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25
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Boot RG, Hollak CE, Verhoek M, Sloof P, Poorthuis BJ, Kleijer WJ, Wevers RA, van Oers MH, Mannens MM, Aerts JM, van Weely S. Glucocerebrosidase genotype of Gaucher patients in The Netherlands: limitations in prognostic value. Hum Mutat 2000; 10:348-58. [PMID: 9375849 DOI: 10.1002/(sici)1098-1004(1997)10:5<348::aid-humu3>3.0.co;2-b] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Gaucher disease is a recessively inherited lysosomal storage disorder that is caused by a deficiency in glucocerebrosidase activity. The clinical expression is markedly heterogeneous with respect to age of onset, progression, severity, and neurological involvement. The relative incidence of glucocerebrosidase (GC) mutations has been studied extensively for Jewish but not for non-Jewish Caucasian patient populations. The present survey on mutant GC genotypes prevalent in Gaucher disease in The Netherlands was taken of 72 patients from different genetic backgrounds. This number is more than half the total number of affected Gaucher patients to be expected on the basis of the incidence of the disorder in this country. Analysis of nine GC mutations led to the identification of 74% of the mutant GC alleles in patients from 44 unrelated Dutch families (i.e., families that have lived in The Netherlands for at least several generations) and of 44% of the mutant GC alleles in patients from nine unrelated families that recently immigrated from both European and non-European countries. The N370S (cDNA 1226G) GC mutation proved to occur most frequently (41%) in the unrelated Dutch patients and less frequently (6%) in the unrelated immigrant patients and was always associated with the nonneuronopathic (Type 1) form of the disease. Apart from the association of the N370S mutation with Type 1 Gaucher disease, the prognostic value of GC genotyping was limited, since a particular GC genotype did not correlate closely to a specific clinical course, or to a specific relative responsiveness to enzyme-supplementation therapy.
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Affiliation(s)
- R G Boot
- Department of Biochemistry, Academic Medical Center, University of Amsterdam, The Netherlands
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26
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Cormand B, Grinberg D, Gort L, Chabás A, Vilageliu L. Molecular analysis and clinical findings in the Spanish Gaucher disease population: putative haplotype of the N370S ancestral chromosome. Hum Mutat 2000; 11:295-305. [PMID: 9554746 DOI: 10.1002/(sici)1098-1004(1998)11:4<295::aid-humu7>3.0.co;2-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Gaucher disease (GD) is an autosomal recessive disorder caused by mutations in the lysosomal beta-glucocerebrosidase (GBA) gene. As the disease is particularly prevalent among Ashkenazi Jews, most studies have been carried out on this ethnic group. In the current study, we present a mutation analysis of the GBA gene in Spanish patients together with the clinical findings. We conducted a systematic analysis in 53 unrelated GD patients. The GBA gene was initially scanned for nine previously described mutations by ASO hybridization or restriction analysis after PCR amplification. The remaining unidentified alleles were screened by nonisotopic PCR-SSCP analysis and sequenced. This approach allowed the identification of 101 of 106 GD alleles (95.3%) involving 24 different mutations, 11 of which are described for the first time: G113E (455G-->A), T134P (517A-->C), G389E (1283G-->A), P391L (1289C-->T), N392I (1292A-->T), Y412H (1351T-->G), W(-4)X (108G-->A), Q169X (662C-->T), R257X (886C-->T), 500insT, and IVS5+1G-->T. Most mutations are present in one or few GD chromosomes. However, two mutations, N370S (1226A-->G) and L444P (1448T-->C), are very frequent and account for 66.1% of the total number of alleles. Linkage disequilibrium was detected between these two mutations and an intragenic polymorphism, indicating that expansion of founder alleles occurred in both cases. Analysis of several microsatellite markers close to the GBA gene allowed us to establish the putative haplotype of the ancestral N370S chromosome.
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Affiliation(s)
- B Cormand
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Spain
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27
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Abstract
Acid beta-glucosidase (GCase) is the enzyme deficient in Gaucher disease, an inherited metabolic prototype for enzyme and gene therapy. An 80-kDa mammalian cytoplasmic protein (TCP80/NF90) was discovered to interact with the GCase mRNA coding region and inhibit its translation in vitro and ex vivo. Human TCP80/NF90 is identical to NF90, an IL-2 enhancer protein, and MPP4, an M-phase phosphoprotein. The interaction of recombinant TCP80/NF90 with GCase mRNA was evaluated using the baculovirus/Sf9 insect cell system since these cells lack this protein. Purified recombinant and isolated mammalian cytoplasmic TCP80/NF90 had identical functions including binding of coding regions of selected RNAs and inhibition of their in vitro translation. Individual baculoviruses containing the human TCP80/NF90 cDNA (vSf9/TCP80) and GCase cDNA (vSf9/GCase) were used to co-infect Sf9 cells. The presence of preformed TCP80/NF90 significantly (>87%) inhibited wild-type GCase mRNA translation in these cells, but baculovirus containing a mutant GCase did not. Sf9 cells co-infected with vSf9/TCP80 showed a major reduction of GCase RNA polysome association. These results show that the multifunctional protein, TCP80/NF90, can function in vivo as a translation inhibitory protein and include alterations of mRNA binding to polysomes as a component of its mechanism of action.
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Affiliation(s)
- Y H Xu
- The Children's Hospital Research Foundation, Cincinnati, Ohio 45229-3039, USA
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28
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Grabowski GA. Gaucher disease: gene frequencies and genotype/phenotype correlations. GENETIC TESTING 1999; 1:5-12. [PMID: 10464619 DOI: 10.1089/gte.1997.1.5] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Gaucher disease is the most prevalent lysosomal storage disease and has its highest incidence in the Ashkenazi Jewish population. Over 100 mutant alleles have been identified in affected patients, but four alleles, termed N370S, L444P, 84GG, and IVS2, have significant frequencies in this population. In affected patients, genotype data show that the presence of a single N370S allele is diagnostic of the type 1 or nonneuronopathic variant, whereas the L444P/L444P genotype is highly associated with neuronopathic variants in the Caucasian population. Large screening studies also indicate a significant underestimation (approximately two-fold) of the prevalence of the N370S/N370S genotype in the affected Ashkenazi Jewish patient population. These results indicate that the N370S/N370S genotype provides a necessary but not sufficient condition for the development of the Gaucher disease phenotype. The genotype/phenotype correlations and gene frequencies have significant impact on genetic counseling of at-risk couples and the future need for therapy of affected patients.
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Affiliation(s)
- G A Grabowski
- Children's Hospital Research Foundation, Cincinnati, OH 45229-3039, USA
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29
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Zimmer KP, le Coutre P, Aerts HM, Harzer K, Fukuda M, O'Brien JS, Naim HY. Intracellular transport of acid beta-glucosidase and lysosome-associated membrane proteins is affected in Gaucher's disease (G202R mutation). J Pathol 1999; 188:407-14. [PMID: 10440752 DOI: 10.1002/(sici)1096-9896(199908)188:4<407::aid-path377>3.0.co;2-z] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Gaucher's disease (GD) is caused by an inherited deficiency of acid beta-glucosidase with storage of glucosylceramides in the lysosomes of macrophages. This study identifies a G202R mutation in the acid beta-glucosidase gene in an infant with severe neuronopathic (type 2) GD and only slightly reduced acid beta-glucosidase activity. Western blot analysis, pulse chase experiments, and the thin frozen section immunogold method were used to analyse the implications of this mutation on the pathogenesis, clinical heterogeneity and diagnostic evaluation of GD. The results show that acid beta-glucosidase persists in the patient's fibroblasts as a mannose-rich polypeptide in the endoplasmic reticulum and is not transported to the lysosomes. By contrast, high expression of the lysosome-associated membrane proteins LAMP-1 and LAMP-2, saposin C, and cathepsin D was observed in the patient's lysosomes. Immunogold labelling of the integral membrane proteins LAMP-1 and LAMP-2 increases significantly at the cell surface of Kupffer cells and fibroblasts as well as at the apical membrane of hepatocytes. In addition, LAMP-1 and LAMP-2 associate with the bilayer of stored glucosylceramide. It is concluded that defective intracellular transport of mutant acid beta-glucosidase from the endoplasmic reticulum to lysosomes leads to a more severe clinical phenotype than the residual enzyme activity may indicate. Furthermore, the detection of LAMP in the tubular bundles of undigested glucosylceramides, as well as their increased concentration at the surfaces of the affected cells, suggests that these proteins play a role in the storage or removal of substrate in GD. Intracellular targeting of acid beta-glucosidase and LAMP contributes to the broad phenotypic heterogeneity of GD.
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Affiliation(s)
- K P Zimmer
- Universitätskinderklinik, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany.
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Wasserstein MP, Martignetti JA, Zeitlin R, Lumerman H, Solomon M, Grace ME, Desnick RJ. Type 1 Gaucher disease presenting with extensive mandibular lytic lesions: Identification and expression of a novel acid ?-glucosidase mutation. ACTA ACUST UNITED AC 1999. [DOI: 10.1002/(sici)1096-8628(19990604)84:4<334::aid-ajmg5>3.0.co;2-p] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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31
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Grace ME, Ashton-Prolla P, Pastores GM, Soni A, Desnick RJ. Non-pseudogene-derived complex acid beta-glucosidase mutations causing mild type 1 and severe type 2 gaucher disease. J Clin Invest 1999; 103:817-23. [PMID: 10079102 PMCID: PMC408142 DOI: 10.1172/jci5168] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Gaucher disease is an autosomal recessive inborn error of glycosphingolipid metabolism caused by the deficient activity of the lysosomal hydrolase, acid beta-glucosidase. Three phenotypically distinct subtypes result from different acid beta-glucosidase mutations encoding enzymes with absent or low activity. A severe neonatal type 2 variant who presented with collodion skin, ichthyosis, and a rapid neurodegenerative course had two novel acid beta-glucosidase alleles: a complex, maternally derived allele, E326K+L444P, and a paternally inherited nonsense mutation, E233X. Because the only other non-pseudogene-derived complex allele, D140H+E326K, also had the E326K lesion and was reported in a mild type 1 patient with a D140H+E326K/K157Q genotype, these complex alleles and their individual mutations were expressed and characterized. Because the E233X mutation expressed no activity and the K157Q allele had approximately 1% normal specific activity based on cross-reacting immunologic material (CRIM SA) in the baculovirus system, the residual activity in both patients was primarily from their complex alleles. In the type 1 patient, the D140H+E326K allele was neuroprotective, encoding an enzyme with a catalytic efficiency similar to that of the N370S enzyme. In contrast, the E326K+L444P allele did not have sufficient activity to protect against the neurologic manifestations and, in combination with the inactive E233X lesion, resulted in the severe neonatal type 2 variant. Thus, characterization of these novel genotypes with non-pseudogene-derived complex mutations provided the pathogenic basis for their diverse phenotypes.
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Affiliation(s)
- M E Grace
- Department of Human Genetics, Mount Sinai School of Medicine, New York, NY 10029, USA.
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32
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Grabowski GA, Horowitz M. Gaucher's disease: molecular, genetic and enzymological aspects. BAILLIERE'S CLINICAL HAEMATOLOGY 1997; 10:635-56. [PMID: 9497856 DOI: 10.1016/s0950-3536(97)80032-7] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The molecular, genetic and enzymological abnormalities in Gaucher's disease have been delineated during the past decade. Although our understanding of the primary predisposition to the Gaucher's disease phenotypes has improved, the relationships remain poorly understood between the mutant alleles, the resultant enzyme variants, the saposin C (activator protein) locus and phenotypes. Of the more than 100-disease associated alleles, about 8 to 10 have significant frequencies in various ethnic and demographic groups. The N370S(1226G) allele is very frequent in Caucasian populations, but absent in Asian groups. In the Ashkenazi Jewish population, the N370S homozygosity predisposes to Gaucher's disease, but over 50% of such patients escape medical detection because of their mild to absent involvement, i.e. N370S may be a prediposing polymorphic variant. Clarification of genotype/phenotype relationships and the identification of modifier loci that impact on Gaucher's disease phenotypes remain a critical area for research. Greater understanding of these issues will facilitate genetic counselling and appropriate interventive therapy to prevent the morbid long-term manifestations of Gaucher's disease.
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Affiliation(s)
- G A Grabowski
- University of Cincinnati College of Medicine, Children's Hospital Medical Center, Ohio 45339-3039, USA
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33
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Yazaki T, Ohnishi M, Rokushika S, Okada G. Subsite structure of the beta-glucosidase from Aspergillus niger, evaluated by steady-state kinetics with cello-oligosaccharides as substrates. Carbohydr Res 1997; 298:51-7. [PMID: 9076931 DOI: 10.1016/s0008-6215(96)00287-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The beta-glucosidase from a commercially available preparation from Aspergillus niger was highly purified. The Michaelis constant Km and the molar activity K0 for cello-oligosaccharide substrates Gn (n = 2-6) were obtained by steady-state kinetic analysis on the beta-glucosidase-catalyzed hydrolysis at 25 degrees C and pH 5.0. Stoichiometric production of Gn-1 by the beta-glucosidase reaction for Gn was confirmed by HPLC techniques. Based on Km and K0 for Gn, subsite affinities (Ai, i = 1-6) were estimated as follows (kcal/mol): A1 = 1.3, A2 = 5.2, A3 = 0.65, A4 = -0.10, A5 = -0.65, and A6 = -0.26, of which A1-A3 are much higher than those of the beta-glucosidase of Candida wickerhamii. The subsite structure is quite similar to that of the alpha-glucosidase of A. niger, whereas the dependence of k0 on n is highly characteristic for beta-glucosidase, and decreases with n, suggesting some interaction between the particular subsites.
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Affiliation(s)
- T Yazaki
- Department of Agricultural and Biological Chemistry, College of Agriculture, University of Kyoto Prefecture, Japan
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34
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Sando GN, Howard EJ, Madison KC. Induction of ceramide glucosyltransferase activity in cultured human keratinocytes. Correlation with culture differentiation. J Biol Chem 1996; 271:22044-51. [PMID: 8703011 DOI: 10.1074/jbc.271.36.22044] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Ceramides are the major component of the extracellular lipids that comprise the epidermal permeability barrier. They are derived from glucosylceramides (GlcCer) upon their extrusion from lamellar granules into the extracellular space in the upper layers of the epidermis. To better understand the regulation of the unique pathway for ceramide production in epidermis, we have studied the activity of the enzyme responsible for GlcCer synthesis, ceramide glucosyltransferase (CerGlc transferase), during keratinocyte culture differentiation. Human keratinocyte cultures were expanded in low calcium keratinocyte growth medium (KGM) and then switched to either normal calcium KGM (nKGM) or "complete" Dulbecco's modified Eagle's medium/Ham's F-12 (3:1) supplemented with 10% fetal bovine serum (cDMEM). At 7 and 10 days after the medium switch, electron microscopy revealed that cDMEM cultures were more fully differentiated morphologically and contained numerous lamellar granules. The GlcCer/DNA content of cDMEM cultures increased to 6 times that of day 0 cultures and was nearly 4 times greater than that of nKGM cultures, whereas the total lipid/DNA content of cDMEM cultures increased to only 1.8 times that of day 0 cultures and was approximately 1.2 times that of nKGM cultures. CerGlc transferase activity/DNA increased 6 times in cDMEM cultures but <1.5 times in nKGM cultures. By contrast, beta-glucocerebrosidase activity, which is responsible for the conversion of GlcCer to ceramide, increased to a similar extent in both differentiating culture systems. Treatment of cultures with the reversible CerGlc transferase inhibitor, DL-threo-1-phenyl-2-(palmitoylamino)-3-morpholino-1-propanol, prevented the increase of GlcCer in cDMEM cultures, and blocked conversion of exogenously added ceramide to GlcCer. A low level of CerGlc transferase activity, relative to that in differentiated keratinocytes, was detected in cultures of other human cell types. These results indicate that CerGlc transferase activity is induced during epidermal differentiation and that regulation of this enzyme may be an important determinant of the specialized production and compartmentalization of epidermal sphingolipids.
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Affiliation(s)
- G N Sando
- Department of Dermatology, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA
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35
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Abstract
DNA from 29 southern African Gaucher disease patients was analyzed for five common Gaucher disease mutations: 1226G, 1448C, 84GG, IVS2 + 1 and 1504T. The origins of the patients were as follows: 14 Ashkenazi Jews; 6 Gentile Caucasoids; 8 Negroids; and one of mixed ancestry. The 1226G allele accounted for 80% of disease alleles in the Jewish patients, 50% of alleles in the Gentile Caucasoid patients and was absent from the Negroid patients. The 1448C allele was present in both the Jewish (1 of 24 alleles) and Negroid patients (3 of 16 alleles). Single-strand conformation polymorphism analysis was successfully used to detect mutation 1226G. This system also revealed the presence of mutation 1297T in a Jewish patient and a novel point mutation, 1277T, in an Afrikaans-speaking Caucasoid patient. Screening of 360 unrelated, healthy Ashkenazi Jewish volunteers to estimate the frequency of disease alleles in the local population led to the detection of 17 carriers: 16 possessed the 1226G allele (frequency = 0.0222), and one the 1297T allele (frequency = 0.0014). Using these results, together with the fact that only 92% of "Gaucher alleles" would be detected in this study, we estimate the disease carrier frequency in the Ashkenazim of South Africa to be 0.05, or approximately 1:20. A reliable carrier screening programme can now be offered to the local Jewish community. The majority of the disease alleles in the two Gentile groups remain uncharacterized.
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Affiliation(s)
- B Morar
- Department of Human Genetics, School of Pathology, South African Institute for Medical Research, Johannesburg
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Grabowski GA, Saal HM, Wenstrup RJ, Barton NW. Gaucher disease: a prototype for molecular medicine. Crit Rev Oncol Hematol 1996; 23:25-55. [PMID: 8817081 DOI: 10.1016/1040-8428(96)00199-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Affiliation(s)
- G A Grabowski
- Division of Human Genetics, Children's Hospital Medical Center, Cincinnati, OH 45229-3039, USA
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37
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Xu YH, Ponce E, Sun Y, Leonova T, Bove K, Witte D, Grabowski GA. Turnover and distribution of intravenously administered mannose-terminated human acid beta-glucosidase in murine and human tissues. Pediatr Res 1996; 39:313-22. [PMID: 8825806 DOI: 10.1203/00006450-199602000-00021] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Gaucher disease type 1, the most prevalent lysosomal storage disease, is caused by the defective activity of the lysosomal enzyme, acid beta-glucosidase, or glucocerebrosidase. Infusion of purified acid beta-glucosidase containing alpha-mannosyl-terminated oligosaccharides (alglucerase) is efficacious in reversing hematologic, hepatic, splenic, and bony disease manifestations. The murine tissue distribution and turnover of bolus injections of alglucerase was evaluated by enzymatic activity, quantitative cross-reacting immunologic material analyses, and immunofluorescence studies. Enzyme activity measurements detected distribution to liver, spleen, thymus, kidney, and bone marrow mononuclear cells, but not to lungs and brain. In kidney and thymus, the enzyme was transiently present. In liver and spleen, enzyme activity peaked at about 20 min postinjection followed by a biphasic decrease with t1/2 approximately 40-60 min and approximately 12-14 h. In bone marrow maximal enzyme activity was at 40-60 min with a disappearance t1/2 approximately 60 min. Quantitative cross-reacting immunologic material studies of liver and spleen showed delivery of enzyme with decreased catalytic rate constants whose degradation included denaturation and proteolytic components. By immunofluorescence the human enzyme was distributed primarily to reticuloendothelial cells of the liver and spleen. In autopsy material from a Gaucher disease type 2 patient treated with enzyme, immunohistochemical and activity studies showed distributions similar to those in mice. These studies indicate a complex delivery and intracellular degradation of acid beta-glucosidase with lower intrinsic activity than the administered therapeutic agent.
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Affiliation(s)
- Y H Xu
- Division of Human Genetics, Children's Hospital Research Foundation, Cincinnati, Ohio, USA
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38
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Sheriff S, Du H, Grabowski GA. Characterization of lysosomal acid lipase by site-directed mutagenesis and heterologous expression. J Biol Chem 1995; 270:27766-72. [PMID: 7499245 DOI: 10.1074/jbc.270.46.27766] [Citation(s) in RCA: 104] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Lysosomal acid lipase (LAL) is essential for the hydrolysis of cholesterol esters and triglycerides that are delivered to the lysosomes via the low density lipoprotein receptor system. The deficiency of LAL is associated with cholesteryl ester storage disease (CESD) and Wolman's disease (WD). We cloned the human LAL cDNA and expressed the active enzyme in the baculovirus system. Two molecular forms (M(r) approximately 41,000 and approximately 46,000) with different glycosylation were found intracellularly, and approximately 24% of the M(r) approximately 46,000 form was secreted into the medium. Tunicamycin treatment produced only an inactive M(r) approximately 41,000 form. This result implicates glycosylation occupancy in the proper folding for active-site function. Catalytic activity was greater toward cis- than trans-unsaturated fatty acid esters of 4-methylumbelliferone and toward esters with 7-carbon length acyl chains. LAL cleaved cholesterol esters and mono-, tri-, and diglycerides. Heparin had a biphasic effect on enzymatic activity with initial activation followed by inhibition. Inhibition of LAL activity by tetrahydrolipstatin and diethyl p-nitrophenyl phosphate suggested the presence of active serines in binding/catalytic domain(s) of the protein. Site-directed mutagenesis at two putative active centers, GXSXG, showed that Ser153 was important to catalytic activity, whereas Ser99 was not and neither was the catalytic nucleophile. Three reported mutations (L179P, L336P, and delta AG302 deletion) from CESD patients were created and expressed in the Sf9 cell system. None cleaved cholesterol esters, and L179P and L336P cleaved only triolein at approximately 4% of wild-type levels. These results suggest that mechanisms, in addition to LAL defects, may operate in the selective accumulation of cholesterol esters or triglycerides in CESD and WD patients.
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Affiliation(s)
- S Sheriff
- Division of Human Genetics, Children's Hospital Research Foundation, Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039, USA
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39
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Affiliation(s)
- D Balicki
- Scripps Research Institute, Department of Molecular and Experimental Medicine, La Jolla, CA 92037, USA
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40
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Affiliation(s)
- V Gieselmann
- Department of Biochemistry II, Georg August Universität, Göttingen, Germany
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41
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Zhu A, Wang ZK, Goldstein J. Identification of tyrosine 108 in coffee bean alpha-galactosidase as an essential residue for the enzyme activity. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1247:260-4. [PMID: 7696317 DOI: 10.1016/0167-4838(94)00228-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The cDNA for coffee bean alpha-galactosidase (alpha-Gal) has been cloned and expressed in a baculovirus expression system. An early study of coconut alpha-Gal by chemical modification suggested that one tyrosine residue is at or near the active site. In order to identify such a critical residue, we replaced two tyrosine residues (positions 108 and 158) with phenylalanine by site-directed mutagenesis. The mutated DNA strands, as well as the wild-type ones, were subcloned into pVL vector and transformed into Sf9 insect cells for intracellular expression. The replacement of Tyr-158 with phenylalanine resulted in a mutant alpha-Gal (Y158F) which retained approx. 88% of the activity of wild-type enzyme. However, the substitution of Tyr-108 by phenylalanine (Y108F) almost abolished the enzymatic activity (1.8% of wild-type activity). The Vmax/Km value for the mutant Y108F was 0.027, which was over a 1000-fold lower than that of wild-type alpha-Gal. Our data suggest that Tyr-108 is critical for the enzymatic activity of alpha-Gal.
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Affiliation(s)
- A Zhu
- Lindsley F. Kimball Research Institute, New York Blood Center, NY 10021
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42
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Beutler E. 2 Gaucher Disease11This is manuscript 8587-MEM from The Scripps Research Institute. Supported by National Institutes of Health Grants DK36639 and RR00833 and the Sam Stein and Rose Stein Charitable Trust Fund. ADVANCES IN GENETICS 1995. [DOI: 10.1016/s0065-2660(08)60202-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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43
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Qi X, Leonova T, Grabowski GA. Functional human saposins expressed in Escherichia coli. Evidence for binding and activation properties of saposins C with acid beta-glucosidase. J Biol Chem 1994. [PMID: 8206997 DOI: 10.1016/s0021-9258(19)89454-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Small (80-amino acid) glycoproteins or saposins are important for the in vivo function of several lysosomal hydrolases. Four saposins, A, B, C, and D, are encoded by a single locus termed prosaposin. Saposins C and A are thought to function in vivo as activators of acid beta-glucosidase. The physiologic role of saposin C has been confirmed, whereas that of saposin A role has not. To investigate the effects of saposins C and A on acid beta-glucosidase activity, the coding sequence for the individual saposins was expressed in Escherichia coli and the recombinant proteins purified to homogeneity. Recombinant and natural saposins A and C activated acid beta-glucosidase similarly only in micromolar amounts. Saposin C had specific activation of acid beta-glucosidase activity at < 200 nM. A second phase of activation was achieved at > 1 microM. In comparison, saposin A consistently activated acid beta-glucosidase only at > 1 microM. Two mutant saposins C (Cys382-->Phe and Cys382--Gly) were created and shown to compete with saposin C for a site on acid beta-glucosidase. The mutant saposins did not activate the enzyme. Recombinant saposin A (< 200 nM) competed with saposin C for a site on the enzyme but without activating effects. These studies show that saposin A is not an in vitro activator of acid beta-glucosidase at physiologic concentrations, although binding occurs without activating acid beta-glucosidase. The studies with mutant saposins C indicate that the binding and activation effects of saposins C are distinct events. These results indicate that the saposin C-induced conformational change in the enzyme occurs via highly specific, probably multivalent, interactions between acid beta-glucosidase and saposin C.
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Affiliation(s)
- X Qi
- Division of Human Genetics, Children's Hospital Research Foundation, Cincinnati, Ohio
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44
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Identification of Glu340 as the active-site nucleophile in human glucocerebrosidase by use of electrospray tandem mass spectrometry. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(19)78077-6] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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45
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Analysis of human acid beta-glucosidase by site-directed mutagenesis and heterologous expression. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)42166-1] [Citation(s) in RCA: 106] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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46
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Abstract
Glucocerebrosidase is a lysosomal enzyme responsible for hydrolysis of glucosylceramide to ceramide and glucose. Mutations disrupting the function of this enzyme cause autosomal recessive Gaucher disease. This disease is very heterogeneous. The clinical heterogeneity is due to a large number of mutations within the gene encoding glucocerebrosidase. To date 36 mutations have been described in Gaucher disease. In this part we present the mutations and review the more common ones. We also review the glucocerebrosidase natural activator, designated saposin C and mutations in its gene, associated with Gaucher disease.
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Affiliation(s)
- M Horowitz
- Department of Cell Research and Immunology, Tel Aviv University, Ramat Aviv, Israel
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47
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Mistry PK, Cox TM. The glucocerebrosidase locus in Gaucher's disease: molecular analysis of a lysosomal enzyme. J Med Genet 1993; 30:889-94. [PMID: 8301642 PMCID: PMC1016594 DOI: 10.1136/jmg.30.11.889] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- P K Mistry
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, UK
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48
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Agmon V, Cherbu S, Dagan A, Grace M, Grabowski GA, Gatt S. Synthesis and use of novel fluorescent glycosphingolipids for estimating beta-glucosidase activity in vitro in the absence of detergents and subtyping Gaucher disease variants following administration into intact cells. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1170:72-9. [PMID: 8399329 DOI: 10.1016/0005-2760(93)90177-b] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Two novel fluorescent glycolipids, LRO-glucosylceramide (LRO-GC) and LRO-trihexosylceramide (LRO-THC) were synthesized and utilized for estimating activities of the lysosomal, acid beta-glucosidase in cell extracts and intact skin fibroblasts, derived from normal individuals and patients with Gaucher disease subtypes. The uniqueness of the glycolipids is the fact that a fluorescent probe (lissamine rhodamine) is linked in a sulfonylamide linkage to the sphingosyl residue of the sphingolipid. Thus, the product of enzymatic hydrolysis, lissamine rhodamine sulfonylamido sphingosine (LRO-ceramide) cannot be further hydrolyzed and remains a metabolic end product. A unique property of LRO-GC as a substrate for the lysosomal, acid beta-glucosidase in vitro was the observation that enzymatic hydrolysis occurs in the absence of detergents and that hydrolytic rates are, in fact, reduced in the presence of Triton X-100 and/or sodium taurocholate. Also, both glycolipids penetrated the membrane of intact fibroblasts in the absence of serum and were hydrolyzed in lysosomes of the intact cells. The rates of intracellular hydrolysis decreased with the severity of the Gaucher disease subtypes. Using LRO-THC as substrate, the intracellular ratio of LRO-ceramide to LRO-glucosylceramide was an indicator for the specific GD-subtype.
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Affiliation(s)
- V Agmon
- Department of Membrane Biochemistry and Neurochemistry, Hebrew University-Hadassah School of Medicine, Jerusalem, Israel
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49
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Abstract
The use of recombinant baculoviruses as high level expression systems is becoming more and more popular. This review aims to provide a summary of the impact of this expression system in biochemistry and biotechnology, highlighting important advances that have been made utilizing the system. The potential of newly developed multiple baculovirus expression systems to enable the reconstruction of complex biological molecules and processes is also reviewed.
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Affiliation(s)
- I M Kidd
- Division of Communicable Diseases, Royal Free Hospital School of Medicine, Hampstead, London
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50
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Berg-Fussman A, Grace M, Ioannou Y, Grabowski G. Human acid beta-glucosidase. N-glycosylation site occupancy and the effect of glycosylation on enzymatic activity. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)82412-7] [Citation(s) in RCA: 31] [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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