1
|
Mahdieh N, Mikaeeli S, Tavasoli AR, Rezaei Z, Maleki M, Rabbani B. Genotype, phenotype and in silico pathogenicity analysis of HEXB mutations: Panel based sequencing for differential diagnosis of gangliosidosis. Clin Neurol Neurosurg 2018; 167:43-53. [PMID: 29448188 DOI: 10.1016/j.clineuro.2018.02.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 01/31/2018] [Accepted: 02/05/2018] [Indexed: 10/18/2022]
Abstract
OBJECTIVES Gangliosidosis is an inherited metabolic disorder causing neurodegeneration and motor regression. Preventive diagnosis is the first choice for the affected families due to lack of straightforward therapy. Genetic studies could confirm the diagnosis and help families for carrier screening and prenatal diagnosis. An update of HEXB gene variants concerning genotype, phenotype and in silico analysis are presented. PATIENTS AND METHODS Panel based next generation sequencing and direct sequencing of four cases were performed to confirm the clinical diagnosis and for reproductive planning. Bioinformatic analyses of the HEXB mutation database were also performed. RESULTS Direct sequencing of HEXA and HEXB genes showed recurrent homozygous variants at c.509G>A (p.Arg170Gln) and c.850C>T (p.Arg284Ter), respectively. A novel variant at c.416T>A (p.Leu139Gln) was identified in the GLB1 gene. Panel based next generation sequencing was performed for an undiagnosed patient which showed a novel mutation at c.1602C>A (p.Cys534Ter) of HEXB gene. Bioinformatic analysis of the HEXB mutation database showed 97% consistency of in silico genotype analysis with the phenotype. Bioinformatic analysis of the novel variants predicted to be disease causing. In silico structural and functional analysis of the novel variants showed structural effect of HEXB and functional effect of GLB1 variants which would provide fast analysis of novel variants. CONCLUSIONS Panel based studies could be performed for overlapping symptomatic patients. Consequently, genetic testing would help affected families for patients' management, carrier detection, and family planning's.
Collapse
Affiliation(s)
- Nejat Mahdieh
- Genetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran.
| | - Sahar Mikaeeli
- Genetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Ali Reza Tavasoli
- Children's Hospital Center, Pediatric Center of Excellence, Tehran University of Medical Center, Tehran, Iran; Growth and Development Research, Tehran University of Medical Sciences, Tehran, Iran
| | - Zahra Rezaei
- Children's Hospital Center, Pediatric Center of Excellence, Tehran University of Medical Center, Tehran, Iran
| | - Majid Maleki
- Genetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Bahareh Rabbani
- Genetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran; Growth and Development Research, Tehran University of Medical Sciences, Tehran, Iran.
| |
Collapse
|
2
|
Gowda VK, Amoghimath R, Srinivasan VM, Bhat M. Sandhoff Disease without Hepatosplenomegaly Due to Hexosaminidase B Gene Mutation. J Pediatr Neurosci 2017; 12:78-79. [PMID: 28553389 PMCID: PMC5437798 DOI: 10.4103/1817-1745.205623] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sandhoff disease is a neurodegenerative disease caused due to deficiency of hexosaminidase (HEX) A and B. A 1-year-old male child presented with regression of milestones, exaggerated startle response, decreased vision, and seizures from 6 months of age. The child had coarse facies without hepatosplenomegaly. Serum levels of β hexosaminidase total (A + B) were low. Genetic testing for Sandhoff disease revealed a homozygous missense variant on HEXB gene. The case is presented to highlight that the absence of hepatosplenomegaly should not restrain in suspecting Sandhoff disease.
Collapse
Affiliation(s)
- Vykuntaraju K Gowda
- Department of Pediatric Neurology, Indira Gandhi Institute of Child Health, Bengaluru, Karnataka, India
| | | | - Varun M Srinivasan
- Department of Pediatric Neurology, Indira Gandhi Institute of Child Health, Bengaluru, Karnataka, India
| | - Maya Bhat
- Department of Neuroradiology, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
| |
Collapse
|
3
|
Fitterer B, Hall P, Antonishyn N, Desikan R, Gelb M, Lehotay D. Incidence and carrier frequency of Sandhoff disease in Saskatchewan determined using a novel substrate with detection by tandem mass spectrometry and molecular genetic analysis. Mol Genet Metab 2014; 111:382-389. [PMID: 24461908 PMCID: PMC4346577 DOI: 10.1016/j.ymgme.2014.01.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 01/04/2014] [Accepted: 01/05/2014] [Indexed: 11/21/2022]
Abstract
Sandhoff disease is a rare progressive neurodegenerative genetic disorder with a high incidence among certain isolated communities and ethnic groups around the world. Previous reports have shown a high occurrence of Sandhoff disease in northern Saskatchewan. Newborn screening cards from northern Saskatchewan were retrospectively screened in order to investigate the incidence and determine the carrier frequency of Sandhoff disease in these communities. PCR-based screening was conducted for the c.115delG (p.(Val39fs)) variant in the HEXB gene that was previously found in 4 Sandhoff disease patients from this area. The carrier frequency for this allele was estimated to be ~1:27. MS/MS-based screening of hexosaminidase activity along with genetic sequencing allowed for the identification of additional variants based on low total hexosaminidase activity and high % hexosaminidase A activity relative to c.115delG carriers. In total 4 pathogenic variants were discovered in the population (c.115delG, c.619A>G, c.1601G>T, and c.1652G>A) of which two are previously unreported (c.1601G>T and c.1652G>A). The combined carrier frequency of these alleles in the study area was estimated at ~1:15. Based on the number of cases of Sandhoff disease from this area we estimate the incidence to be ~1:390 corresponding to a child being born with the disease every 1-2 years on average. The results from our study were then compared with variants in the HEXB gene from the genomes available from the 1000 Genomes project. A total of 19 HEXB variants were found in the 1092 genomes of which 5 are suspected of having a deleterious effect on hexosaminidase activity. The estimated carrier frequency of Sandhoff disease in Saskatchewan at 1:15 is more than 3 times higher than the carrier frequency in the global sample provided by the 1000 Genomes project at 1:57.
Collapse
Affiliation(s)
- Braden Fitterer
- Molecular Diagnostics, Saskatchewan Disease Control Laboratory, 5 Research Drive, Regina, SK S4S 0A4, Canada.
| | - Patricia Hall
- Molecular Diagnostics, Saskatchewan Disease Control Laboratory, 5 Research Drive, Regina, SK S4S 0A4, Canada; Department of Human Genetics, Emory University, Atlanta, GA 30033, USA.
| | - Nick Antonishyn
- Molecular Diagnostics, Saskatchewan Disease Control Laboratory, 5 Research Drive, Regina, SK S4S 0A4, Canada.
| | - Rajagopal Desikan
- Department of Chemistry, Campus Box 351700, University of Washington, Seattle, WA 98195, USA; Department of Biochemistry, Campus Box 351700, University of Washington, Seattle, WA 98195, USA
| | - Michael Gelb
- Department of Chemistry, Campus Box 351700, University of Washington, Seattle, WA 98195, USA; Department of Biochemistry, Campus Box 351700, University of Washington, Seattle, WA 98195, USA.
| | - Denis Lehotay
- Molecular Diagnostics, Saskatchewan Disease Control Laboratory, 5 Research Drive, Regina, SK S4S 0A4, Canada.
| |
Collapse
|
4
|
Kodama T, Togawa T, Tsukimura T, Kawashima I, Matsuoka K, Kitakaze K, Tsuji D, Itoh K, Ishida YI, Suzuki M, Suzuki T, Sakuraba H. Lyso-GM2 ganglioside: a possible biomarker of Tay-Sachs disease and Sandhoff disease. PLoS One 2011; 6:e29074. [PMID: 22205997 PMCID: PMC3243693 DOI: 10.1371/journal.pone.0029074] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2011] [Accepted: 11/20/2011] [Indexed: 11/18/2022] Open
Abstract
To find a new biomarker of Tay-Sachs disease and Sandhoff disease. The lyso-GM2 ganglioside (lyso-GM2) levels in the brain and plasma in Sandhoff mice were measured by means of high performance liquid chromatography and the effect of a modified hexosaminidase (Hex) B exhibiting Hex A-like activity was examined. Then, the lyso-GM2 concentrations in human plasma samples were determined. The lyso-GM2 levels in the brain and plasma in Sandhoff mice were apparently increased compared with those in wild-type mice, and they decreased on intracerebroventricular administration of the modified Hex B. The lyso-GM2 levels in plasma of patients with Tay-Sachs disease and Sandhoff disease were increased, and the increase in lyso-GM2 was associated with a decrease in Hex A activity. Lyso-GM2 is expected to be a potential biomarker of Tay-Sachs disease and Sandhoff disease.
Collapse
Affiliation(s)
- Takashi Kodama
- Department of Analytical Biochemistry, Meiji Pharmaceutical University, Tokyo, Japan
| | - Tadayasu Togawa
- Department of Analytical Biochemistry, Meiji Pharmaceutical University, Tokyo, Japan
| | - Takahiro Tsukimura
- Department of Analytical Biochemistry, Meiji Pharmaceutical University, Tokyo, Japan
| | - Ikuo Kawashima
- Department of Clinical Genetics, Meiji Pharmaceutical University, Tokyo, Japan
- Department of Molecular Medical Research, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Kazuhiko Matsuoka
- Department of Medicinal Biotechnology, Institute for Medicinal Research, Graduate School of Pharmaceutical Sciences, The University of Tokushima, Tokushima, Japan
| | - Keisuke Kitakaze
- Department of Medicinal Biotechnology, Institute for Medicinal Research, Graduate School of Pharmaceutical Sciences, The University of Tokushima, Tokushima, Japan
| | - Daisuke Tsuji
- Department of Medicinal Biotechnology, Institute for Medicinal Research, Graduate School of Pharmaceutical Sciences, The University of Tokushima, Tokushima, Japan
| | - Kohji Itoh
- Department of Medicinal Biotechnology, Institute for Medicinal Research, Graduate School of Pharmaceutical Sciences, The University of Tokushima, Tokushima, Japan
| | - Yo-ichi Ishida
- Department of Molecular Biochemistry, Meiji Pharmaceutical University, Tokyo, Japan
| | - Minoru Suzuki
- Disease Glycomics Team, Systems Glycobiology Research Group, RIKEN, Saitama, Japan
| | - Toshihiro Suzuki
- Department of Analytical Biochemistry, Meiji Pharmaceutical University, Tokyo, Japan
| | - Hitoshi Sakuraba
- Department of Analytical Biochemistry, Meiji Pharmaceutical University, Tokyo, Japan
- Department of Clinical Genetics, Meiji Pharmaceutical University, Tokyo, Japan
- * E-mail:
| |
Collapse
|
5
|
Kawashima N, Tsuji D, Okuda T, Itoh K, Nakayama KI. Mechanism of abnormal growth in astrocytes derived from a mouse model of GM2 gangliosidosis. J Neurochem 2009; 111:1031-41. [DOI: 10.1111/j.1471-4159.2009.06391.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
6
|
Intra J, Pavesi G, Horner DS. Phylogenetic analyses suggest multiple changes of substrate specificity within the glycosyl hydrolase 20 family. BMC Evol Biol 2008; 8:214. [PMID: 18647384 PMCID: PMC2492878 DOI: 10.1186/1471-2148-8-214] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Accepted: 07/22/2008] [Indexed: 12/14/2022] Open
Abstract
Background Beta-N-acetylhexosaminidases belonging to the glycosyl hydrolase 20 (GH20) family are involved in the removal of terminal β-glycosidacally linked N-acetylhexosamine residues. These enzymes, widely distributed in microorganisms, animals and plants, are involved in many important physiological and pathological processes, such as cell structural integrity, energy storage, pathogen defence, viral penetration, cellular signalling, fertilization, development of carcinomas, inflammatory events and lysosomal storage diseases. Nevertheless, only limited analyses of phylogenetic relationships between GH20 genes have been performed until now. Results Careful phylogenetic analyses of 233 inferred protein sequences from eukaryotes and prokaryotes reveal a complex history for the GH20 family. In bacteria, multiple gene duplications and lineage specific gene loss (and/or horizontal gene transfer) are required to explain the observed taxonomic distribution. The last common ancestor of extant eukaryotes is likely to have possessed at least one GH20 family member. At least one gene duplication before the divergence of animals, plants and fungi as well as other lineage specific duplication events have given rise to multiple paralogous subfamilies in eukaryotes. Phylogenetic analyses also suggest that a second, divergent subfamily of GH20 family genes present in animals derive from an independent prokaryotic source. Our data suggest multiple convergent changes of functional roles of GH20 family members in eukaryotes. Conclusion This study represents the first detailed evolutionary analysis of the glycosyl hydrolase GH20 family. Mapping of data concerning physiological function of GH20 family members onto the phylogenetic tree reveals that apparently convergent and highly lineage specific changes in substrate specificity have occurred in multiple GH20 subfamilies.
Collapse
Affiliation(s)
- Jari Intra
- Dipartimento di Scienze Biomolecolari e Biotecnologie, Università di Milano, Via Celoria 26, 20133 Milano, Italy.
| | | | | |
Collapse
|
7
|
Tomiya N, Narang S, Park J, Abdul-Rahman B, Choi O, Singh S, Hiratake J, Sakata K, Betenbaugh MJ, Palter KB, Lee YC. Purification, Characterization, and Cloning of a Spodoptera frugiperda Sf9 β-N-Acetylhexosaminidase That Hydrolyzes Terminal N-Acetylglucosamine on the N-Glycan Core. J Biol Chem 2006; 281:19545-60. [PMID: 16684772 DOI: 10.1074/jbc.m603312200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Paucimannosidic glycans are often predominant in N-glycans produced by insect cells. However, a beta-N-acetylhexosaminidase responsible for the generation of paucimannosidic glycans in lepidopteran insect cells has not been identified. We report the purification of a beta-N-acetylhexosaminidase from the culture medium of Spodoptera frugiperda Sf9 cells (Sfhex). The purified Sfhex protein showed 10 times higher activity for a terminal N-acetylglucosamine on the N-glycan core compared with tri-N-acetylchitotriose. Sfhex was found to be a homodimer of 110 kDa in solution, with a pH optimum of 5.5. With a biantennary N-glycan substrate, it exhibited a 5-fold preference for removal of the beta(1,2)-linked N-acetylglucosamine from the Man alpha(1,3) branch compared with the Man alpha(1,6) branch. We isolated two corresponding cDNA clones for Sfhex that encode proteins with >99% amino acid identity. A phylogenetic analysis suggested that Sfhex is an ortholog of mammalian lysosomal beta-N-acetylhexosaminidases. Recombinant Sfhex expressed in Sf9 cells exhibited the same substrate specificity and pH optimum as the purified enzyme. Although a larger amount of newly synthesized Sfhex was secreted into the culture medium by Sf9 cells, a significant amount of Sfhex was also found to be intracellular. Under a confocal microscope, cellular Sfhex exhibited punctate staining throughout the cytoplasm, but did not colocalize with a Golgi marker. Because secretory glycoproteins and Sfhex are cotransported through the same secretory pathway and because Sfhex is active at the pH of the secretory compartments, this study suggests that Sfhex may play a role as a processing beta-N-acetylhexosaminidase acting on N-glycans from Sf9 cells.
Collapse
Affiliation(s)
- Noboru Tomiya
- Department of Biology, The Johns Hopkins University, Baltimore, Maryland 21218, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Itakura T, Kuroki A, Ishibashi Y, Tsuji D, Kawashita E, Higashine Y, Sakuraba H, Yamanaka S, Itoh K. Inefficiency in GM2 Ganglioside Elimination by Human Lysosomal .BETA.-Hexosaminidase .BETA.-Subunit Gene Transfer to Fibroblastic Cell Line Derived from Sandhoff Disease Model Mice. Biol Pharm Bull 2006; 29:1564-9. [PMID: 16880605 DOI: 10.1248/bpb.29.1564] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sandhoff disease (SD) is an autosomal recessive GM2 gangliosidosis caused by the defect of lysosomal beta-hexosaminidase (Hex) beta-subunit gene associated with neurosomatic manifestations. Therapeutic effects of Hex subunit gene transduction have been examined on Sandhoff disease model mice (SD mice) produced by the allelic disruption of Hexb gene encoding the murine beta-subunit. We demonstrate here that elimination of GM2 ganglioside (GM2) accumulated in the fibroblastic cell line derived from SD mice (FSD) did not occur when the HEXB gene only was transfected. In contrast, a significant increase in the HexB (betabeta homodimer) activity toward neutral substrates, including GA2 (asialo-GM2) and oligosaccharides carrying the terminal N-acetylglucosamine residues at their non-reducing ends (GlcNAc-oligosaccharides) was observed. Immunoblotting with anti-human HexA (alphabeta heterodimer) serum after native polyacrylamide gel electrophoresis (Native-PAGE) revealed that the human HEXB gene product could hardly form the chimeric HexA through associating with the murine alpha-subunit. However, co-introduction of the HEXA encoding the human alpha-subunit and HEXB genes caused significant corrective effect on the GM2 degradation by producing the human HexA. These results indicate that the recombinant human HexA could interspeciesly associate with the murine GM2 activator protein to degrade GM2 accumulated in the FSD cells. Thus, therapeutic effects of the recombinant human HexA isozyme but not human HEXB gene product could be evaluated by using the SD mice.
Collapse
Affiliation(s)
- Tomohiro Itakura
- Department of Medicinal Biotechnology, Institute for Medicinal Resources, Graduate School of Pharmaceutical Sciences, The University of Tokushima, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Tsuji D, Kuroki A, Ishibashi Y, Itakura T, Itoh K. Metabolic correction in microglia derived from Sandhoff disease model mice. J Neurochem 2005; 94:1631-8. [PMID: 16092933 DOI: 10.1111/j.1471-4159.2005.03317.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Sandhoff disease is an autosomal recessive lysosomal storage disease caused by a defect of the beta-subunit gene (HEXB) associated with simultaneous deficiencies of beta-hexosaminidase A (HexA; alphabeta) and B (HexB; betabeta), and excessive accumulation of GM2 ganglioside (GM2) and oligosaccharides with N-acetylglucosamine (GlcNAc) residues at their non-reducing termini. Recent studies have shown the involvement of microglial activation in neuroinflammation and neurodegeneration of this disease. We isolated primary microglial cells from the neonatal brains of Sandhoff disease model mice (SD mice) produced by disruption of the murine Hex beta-subunit gene allele (Hexb-/-). The cells expressed microglial cell-specific ionized calcium binding adaptor molecule 1 (Iba1)-immunoreactivity (IR) and antigen recognized by Ricinus communis agglutinin lectin-120 (RCA120), but not glial fibrillary acidic protein (GFAP)-IR specific for astrocytes. They also demonstrated significant intracellular accumulation of GM2 and GlcNAc-oligosaccharides. We produced a lentiviral vector encoding for the murine Hex beta-subunit and transduced it into the microglia from SD mice with the recombinant lentivirus, causing elimination of the intracellularly accumulated GM2 and GlcNAc-oligosaccharides and secretion of Hex isozyme activities from the transduced SD microglial cells. Recomibinant HexA isozyme isolated from the conditioned medium of a Chinese hamster ovary (CHO) cell line simultaneously expressing the human HEXA (alpha-subunit) and HEXB genes was also found to be incorporated into the SD microglia via cell surface cation-independent mannose 6-phosphate receptor and mannose receptor to degrade the intracellularly accumulated GM2 and GlcNAc-oligosaccharides. These results suggest the therapeutic potential of recombinant lentivirus encoding the murine Hex beta-subunit and the human HexA isozyme (alphabeta heterodimer) for metabolic cross-correction in microglial cells involved in progressive neurodegeneration in SD mice.
Collapse
Affiliation(s)
- Daisuke Tsuji
- Department of Medicinal Biotechnology, Institute for Medicinal Resources, Graduate School of Pharmaceutical Sciences, The University of Tokushima, 178 Sho-machi, Tokushima, Japan
| | | | | | | | | |
Collapse
|
10
|
Tsuji D, Kuroki A, Ishibashi Y, Itakura T, Kuwahara J, Yamanaka S, Itoh K. Specific induction of macrophage inflammatory protein 1-alpha in glial cells of Sandhoff disease model mice associated with accumulation of N-acetylhexosaminyl glycoconjugates. J Neurochem 2005; 92:1497-507. [PMID: 15748167 DOI: 10.1111/j.1471-4159.2005.02986.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Sandhoff disease is a lysosomal storage disease caused by simultaneous deficiencies of beta-hexosaminidase A (HexA; alphabeta) and B (HexB; betabeta), due to a primary defect of the beta-subunit gene (HEXB) associated with excessive accumulation of GM2 ganglioside (GM2) and oligosaccharides with N-acetylhexosamine residues at their non-reducing termini, and with neurosomatic manifestations. To elucidate the neuroinflammatory mechanisms involved in its pathogenesis, we analyzed the expression of chemokines in Sandhoff disease model mice (SD mice) produced by disruption of the murine Hex beta-subunit gene allele (Hexb-/-). We demonstrated that chemokine macrophage inflammatory protein-1 alpha (MIP-1alpha) was induced in brain regions, including the cerebral cortex, brain stem and cerebellum, of SD mice from an early stage of the pathogenesis but not in other systemic organs. On the other hand, little changes in other chemokine mRNAs, including those of RANTES (regulated upon activation, normal T expressed and secreted), MCP-1 (monocyte chemotactic protein-1), SLC (secondary lymphoid-tissue chemokine), fractalkine and SDF-1 (stromal derived factor-1), were detected. Significant up-regulation of MIP-1alpha mRNA and protein in the above-mentioned brain regions was observed in parallel with the accumulation of natural substrates of HexA and HexB. Immunohistochemical analysis revealed that MIP-1alpha-immunoreactivity (IR) in the above-mentioned brain regions of SD mice was co-localized in Iba1-IR-positive microglial cells and partly in glial fibrillary acidic protein (GFAP)-IR-positive astrocytes, in which marked accumulation of N-acetylglucosaminyl (GlcNAc)-oligosaccharides was observed from the presymptomatic stage of the disease. In contrast, little MIP-1alpha-IR was observed in neurons in which GM2 accumulated predominantly. These results suggest that specific induction of MIP-1alpha might coincide with the accumulation of GlcNAc-oligosaccharides due to a HexB deficiency in resident microglia and astrocytes in the brains of SD mice causing their activation and acceleration of the progressive neurodegeneration in SD mice.
Collapse
Affiliation(s)
- Daisuke Tsuji
- Department of Medicinal Biotechnology, Institute of Medicinal Resources, Graduate School of Pharmaceutical Sciences, The University of Tokushima, 1-78 Sho-machi, Tokushima 770-8505, Japan
| | | | | | | | | | | | | |
Collapse
|
11
|
Maier T, Strater N, Schuette CG, Klingenstein R, Sandhoff K, Saenger W. The X-ray crystal structure of human beta-hexosaminidase B provides new insights into Sandhoff disease. J Mol Biol 2003; 328:669-81. [PMID: 12706724 DOI: 10.1016/s0022-2836(03)00311-5] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Human lysosomal beta-hexosaminidases are dimeric enzymes composed of alpha and beta-chains, encoded by the genes HEXA and HEXB. They occur in three isoforms, the homodimeric hexosaminidases B (betabeta) and S (alphaalpha), and the heterodimeric hexosaminidase A (alphabeta), where dimerization is required for catalytic activity. Allelic variations in the HEXA and HEXB genes cause the fatal inborn errors of metabolism Tay-Sachs disease and Sandhoff disease, respectively. Here, we present the crystal structure of a complex of human beta-hexosaminidase B with a transition state analogue inhibitor at 2.3A resolution (pdb 1o7a). On the basis of this structure and previous studies on related enzymes, a retaining double-displacement mechanism for glycosyl hydrolysis by beta-hexosaminidase B is proposed. In the dimer structure, which is derived from an analysis of crystal packing, most of the mutations causing late-onset Sandhoff disease reside near the dimer interface and are proposed to interfere with correct dimer formation. The structure reported here is a valid template also for the dimeric structures of beta-hexosaminidase A and S.
Collapse
Affiliation(s)
- Timm Maier
- Institut für Chemie Kristallographie, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | | | | | | | | | | |
Collapse
|
12
|
Mark BL, Mahuran DJ, Cherney MM, Zhao D, Knapp S, James MNG. Crystal structure of human beta-hexosaminidase B: understanding the molecular basis of Sandhoff and Tay-Sachs disease. J Mol Biol 2003; 327:1093-109. [PMID: 12662933 PMCID: PMC2910754 DOI: 10.1016/s0022-2836(03)00216-x] [Citation(s) in RCA: 164] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In humans, two major beta-hexosaminidase isoenzymes exist: Hex A and Hex B. Hex A is a heterodimer of subunits alpha and beta (60% identity), whereas Hex B is a homodimer of beta-subunits. Interest in human beta-hexosaminidase stems from its association with Tay-Sachs and Sandhoff disease; these are prototypical lysosomal storage disorders resulting from the abnormal accumulation of G(M2)-ganglioside (G(M2)). Hex A degrades G(M2) by removing a terminal N-acetyl-D-galactosamine (beta-GalNAc) residue, and this activity requires the G(M2)-activator, a protein which solubilizes the ganglioside for presentation to Hex A. We present here the crystal structure of human Hex B, alone (2.4A) and in complex with the mechanistic inhibitors GalNAc-isofagomine (2.2A) or NAG-thiazoline (2.5A). From these, and the known X-ray structure of the G(M2)-activator, we have modeled Hex A in complex with the activator and ganglioside. Together, our crystallographic and modeling data demonstrate how alpha and beta-subunits dimerize to form either Hex A or Hex B, how these isoenzymes hydrolyze diverse substrates, and how many documented point mutations cause Sandhoff disease (beta-subunit mutations) and Tay-Sachs disease (alpha-subunit mutations).
Collapse
Affiliation(s)
- Brian L. Mark
- Canadian Institutes of Heath Research Group in Protein Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, Alt.,Canada T6G 2H7
| | - Don J. Mahuran
- The Research Institute, The Hospital for Sick Children, 555 University Ave, Toronto Ont., Canada M5G1X8
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ont., Canada M5G1L6
| | - Maia M. Cherney
- Canadian Institutes of Heath Research Group in Protein Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, Alt.,Canada T6G 2H7
| | - Dalian Zhao
- Department of Chemistry, Rutgers University, New Brunswick, NJ 08903, USA
| | - Spencer Knapp
- Department of Chemistry, Rutgers University, New Brunswick, NJ 08903, USA
| | - Michael N. G. James
- Canadian Institutes of Heath Research Group in Protein Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, Alt.,Canada T6G 2H7
- Corresponding author:
| |
Collapse
|
13
|
Utsumi K, Tsuji A, Kase R, Tanaka A, Tanaka T, Uyama E, Ozawa T, Sakuraba H, Komaba Y, Kawabe M, Iino Y, Katayama Y. Western blotting analysis of the beta-hexosaminidase alpha- and beta-subunits in cultured fibroblasts from cases of various forms of GM2 gangliosidosis. Acta Neurol Scand 2002; 105:427-30. [PMID: 12027830 DOI: 10.1034/j.1600-0404.2002.01097.x] [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: 11/23/2022]
Abstract
OBJECTIVES The GM2 gangliosidoses are a group of genetic disorders caused by the accumulation of ganglioside GM2 in neuronal cells. We examined the alpha- and beta-subunits of beta-hexosaminidases by a non-radioisotopes detecting system to evaluate whether it was a useful method for understanding of the pathophysiologies of GM2 gangliosidoses. MATERIALS AND METHODS We investigated the alpha- and beta-subunits of beta-hexosaminidases in cultured fibroblasts from cases of various forms of GM2 gangliosidosis by means of Western blotting and a chemiluminescence detection system. RESULTS In a patient with infantile Tay-Sachs disease [HEXA genotype, Int5-SA(g-1-->t)/Int5-SA(g-1-->t)], the mature alpha-subunit was undetectable. In a patient with infantile Sandhoff disease (HEXB genotype, C534Y/C534Y), the mature beta-subunit was deficient. However, a small amount of the mature beta-subunit was detected in a patient with adult Sandhoff disease (HEXB genotype, R505Q(+I207V)/R505Q(+I207V)), which may have resulted in the residual enzyme activity and mild clinical course. Normal amounts of alpha- and beta-subunits were detected in a patient with GM2 activator deficiency. CONCLUSION This method is easy and sensitive for detecting target proteins, and is useful for clarification of the pathophysiologies of GM2 gangliosidoses.
Collapse
Affiliation(s)
- K Utsumi
- The Second Department of Internal Medicine, Nippon Medical School, Bunkyo-ku, Tokyo, Japan. utsumi_kouichi/
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Triggs-Raine B, Mahuran DJ, Gravel RA. Naturally occurring mutations in GM2 gangliosidosis: a compendium. ADVANCES IN GENETICS 2002; 44:199-224. [PMID: 11596984 DOI: 10.1016/s0065-2660(01)44081-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- B Triggs-Raine
- Department of Biochemistry and Medical Genetics University of Manitoba, Winnipeg, Canada.
| | | | | |
Collapse
|
15
|
Schuette CG, Weisgerber J, Sandhoff K. Complete analysis of the glycosylation and disulfide bond pattern of human beta-hexosaminidase B by MALDI-MS. Glycobiology 2001; 11:549-56. [PMID: 11447134 DOI: 10.1093/glycob/11.7.549] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
beta-hexosaminidase B is an enzyme that is involved in the degradation of glycolipids and glycans in the lysosome. Mutation in the HEXB gene lead to Sandhoff disease, a glycolipid storage disorder characterized by severe neurodegeneration. So far, little structural information on the protein is available. Here, the complete analysis of the disulfide bond pattern of the protein is described for the first time. Additionally, the structures of the N-glycans are analyzed for the native human protein and for recombinant protein expressed in SF21 cells. For the analysis of the disulfide bond structure, the protein was proteolytically digested and the resulting peptides were analyzed by MALDI-MS. The analysis revealed three disulfide bonds (C91-C137; C309-C360; C534-C551) and a free cysteine (C487). The analysis of the N-glycosylation was performed by tryptic digestion of the protein, isolation of glycopeptides by lectin chromatography and mass measurement before and after enzymatic deglycosylation. Carbohydrate structures were calculated from the mass difference between glycosylated and deglycosylated peptide. For beta-hexosaminidase B from human placenta, four N-glycans were identified and analyzed, whereas the recombinant protein expressed in SF21 cells carried only three glycans. In both cases the glycosylation belongs to the mannose-core- or high-mannose-type, and some carbohydrate structures are fucosylated.
Collapse
Affiliation(s)
- C G Schuette
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Str. 1, D-53121 Bonn, Germany
| | | | | |
Collapse
|
16
|
Furihata K, Drousiotou A, Hara Y, Christopoulos G, Stylianidou G, Anastasiadou V, Ueno I, Ioannou P. Novel splice site mutation at IVS8 nt 5 of HEXB responsible for a Greek-Cypriot case of Sandhoff disease. Hum Mutat 2000; 13:38-43. [PMID: 9888387 DOI: 10.1002/(sici)1098-1004(1999)13:1<38::aid-humu4>3.0.co;2-s] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Sandhoff disease is caused by abnormalities in HEXB gene encoding the beta-subunit of beta-hexosaminidase. In this study, we analyzed the HEXB gene of a Sandhoff carrier in the Greek-Cypriot community. A G to C transversion was identified in one allele of her HEXB gene at position 5 of the 5'-splice site of intron 8 (IVS8 nt5). One of 13 cDNA clones derived from her lymphocyte HEXB mRNA lacked the last four nucleotides "GTTG" of exon 8, which created a premature termination codon at 11 codons downstream. In vivo transcription of the mutant HEXB gene fragment in CHO cells resulted in deletion of the "GTTG." The mutation has not been found in 40 DNA samples from anonymous donors, indicating that this is not a polymorphism in the Cypriot population. These results clearly indicate that the splice site mutation at IVS8 nt5 is responsible for this case of Sandhoff disease.
Collapse
Affiliation(s)
- K Furihata
- Department of Laboratory Medicine, Shinshu University School of Medicine, Matsumoto, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Mahuran DJ. Biochemical consequences of mutations causing the GM2 gangliosidoses. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1455:105-38. [PMID: 10571007 DOI: 10.1016/s0925-4439(99)00074-5] [Citation(s) in RCA: 199] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The hydrolysis of GM2-ganglioside is unusual in its requirements for the correct synthesis, processing, and ultimate combination of three gene products. Whereas two of these proteins are the alpha- (HEXA gene) and beta- (HEXB) subunits of beta-hexosaminidase A, the third is a small glycolipid transport protein, the GM2 activator protein (GM2A), which acts as a substrate specific co-factor for the enzyme. A deficiency of any one of these proteins leads to storage of the ganglioside, primarily in the lysosomes of neuronal cells, and one of the three forms of GM2-gangliosidosis, Tay-Sachs disease, Sandhoff disease or the AB-variant form. Studies of the biochemical impact of naturally occurring mutations associated with the GM2 gangliosidoses on mRNA splicing and stability, and on the intracellular transport and stability of the affected protein have provided some general insights into these complex cellular mechanisms. However, such studies have revealed little in the way of structure-function information on the proteins. It appears that the detrimental effect of most mutations is not specifically on functional elements of the protein, but rather on the proteins' overall folding and/or intracellular transport. The few exceptions to this generalization are missense mutations at two codons in HEXA, causing the unique biochemical phenotype known as the B1-variant, and one codon in both the HEXB and GM2A genes. Biochemical characterization of these mutations has led to the localization of functional residues and/or domains within each of the encoded proteins.
Collapse
Affiliation(s)
- D J Mahuran
- Research Institute, The Hospital for Sick Children, Toronto, Ont, Canada.
| |
Collapse
|
18
|
Hara A, Uyama E, Uchino M, Shimmoto M, Utsumi K, Itoh K, Kase R, Naito M, Sugiyama E, Taketomi T, Sukegawa K, Sakuraba H. Adult Sandhoff's disease: R505Q and I207V substitutions in the HEXB gene of the first Japanese case. J Neurol Sci 1998; 155:86-91. [PMID: 9562328 DOI: 10.1016/s0022-510x(97)00299-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We describe a 31-year-old Japanese man with adult Sandhoff s disease presenting as spinocerebellar degeneration. There was a marked cerebellar atrophy on MRI, and proliferation of abundant PAS-positive foamy macrophages in the rectal mucosa. The activities of total beta-Hex, beta-Hex A, and beta-Hex B in leucocytes of the patient were 14%, 15%, and 6% of control values, respectively. However, oligosacchariduria or ultrastructural storage materials in liver tissue were nil. Direct sequencing of cDNA and genomic DNA, and restriction digestion revealed two different homozygous base substitutions in the HEXB gene: the G1514-->A substitution (R505Q) and the A619-->G substitution (1207V). The parents were consanguineous. His healthy mother, an enzymatic heterozygous carrier, was homozygous for 1207V, but heterozygous for R505Q mutation. Thus, the patient is probably homozygous for both base substitutions and a R505Q mutation may be linked to the phenotype of adult Sandhoff's disease.
Collapse
Affiliation(s)
- A Hara
- Department of Neurology, Kumamoto University School of Medicine, Japan
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Sakuraba H, Itoh K, Kuroki Y, Kase R, Shimmoto M, Utsumi K, Ozawa H, Tai T, Hara A, Uyama E. Immunocytochemical detection of accumulated substrates in cultured fibroblasts from patients with the infantile and adult forms of Sandhoff disease. Clin Chim Acta 1997; 265:263-6. [PMID: 9385467 DOI: 10.1016/s0009-8981(97)00143-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
|
20
|
Ozawa H, Yamashita K, Sakuraba H, Itoh K, Kase R, Tai T. Generation and characterization of mouse monoclonal antibodies specific for N-linked neutral oligosaccharides of glycoproteins. Arch Biochem Biophys 1997; 342:48-57. [PMID: 9185613 DOI: 10.1006/abbi.1997.9993] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We generated four monoclonal antibodies (MAbs) specific for asparagine-linked neutral oligosaccharides of glycoproteins by immunizing mice with neoglycolipids, which were derived from glycoproteins by conjugation to phosphatidylethanolamine dipalmitoyl. The binding specificity of these MAbs was determined by an enzyme-linked immunosorbent assay and immunostaining on thin-layer chromatography. The four MAbs designated OMB3, OMB4, OMR5, and OMR6 reacted strongly with the neoglycolipids, Gal beta1-4GlcNAc beta1-2Man alpha1-6(Gal beta1-4GlcNAc beta1-2Man alpha1-3)Man beta1-4GlcNAc-PD, GlcNAc beta1-2Man alpha1-6(GlcNAc beta1-2Man alpha1-3)(GlcNAc beta1-4)Man beta1-4GlcNAc beta1-4GlcNAc-PD, Man alpha1-6Man beta1-4GlcNAc beta1-4(Fuc alpha1-6)GlcNAc-PD, and Man alpha1-3Man beta1-4GlcNAc-PD, respectively, that were used as immunogens. All of these MAbs exhibited a high binding specificity. The epitopes of the MAbs OMB3 and OMB4 were suggested to be nonreducing terminal trisaccharides, Gal beta1-4GlcNAc beta1-2Man-, and nonreducing beta-GlcNAc residues, respectively. MAbs OMR5 and OMR6 showed a highly restricted binding specificity, reacting only with the immunizing neoglycolipids. Subsequently, MAbs OMB3 and OMB4 were shown to react strongly with asialo-alpha1-acid-glycoprotein and asialo-agalacto-alpha1-acid-glycoprotein, respectively, by Western blotting. Furthermore, it was shown that these MAbs reacted specifically with the epitope on Chinese hamster ovary cells by an immunofluorescence technique. MAb OMB4 was also shown to detect the accumulated oligosaccharides with nonreducing terminal beta-GlcNAc residues as granular inclusions in the cultured fibroblasts from a classical Sandhoff disease patient.
Collapse
Affiliation(s)
- H Ozawa
- Department of Tumor Immunology, The Tokyo Metropolitan Institute of Medical Science, Bunkyo-ku, Japan
| | | | | | | | | | | |
Collapse
|