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Wang Y, Zhang JY, Teng JY, Xiong HF, Li QF. Biochemical characteristics of point mutated Capra hircus lysosome α-mannosidase. J Vet Med Sci 2023; 85:244-251. [PMID: 36596563 PMCID: PMC10017285 DOI: 10.1292/jvms.22-0222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Locoweeds, a type of poisonous weedare, are widely distributed throughout the world and have a significant impact on the development of herbivore animal husbandry. Swainsonine (SW), the main toxin in locoweeds, can competitively inhibit lysosomes α-mannosidase (LAM) in animal cells, resulting in α-mannosidosis. However, the specifics of the interaction between SW and LAM are still unclear. Here, we used molecular docking to predicte the interaction points between SW and LAM, built mutated lysosomes α-mannosidase (LAMM), and analyzed its biochemical properties changes in presumption points. The Trp at the 28th position and the Tyr at the 599th position of the LAM were interaction point candidates, and the above two amino acids in Capra hircus LAM (chLAM), were successfully mutated to glycine by constructing recombinant yeast GS115/PIC9K- LAMM. The results showed that the sensitivity of Capra hircus LAMM (chLAMM), to SW decreased significantly compared with wild-type LAM, the enzyme activity of LAM decreased approximately threefold, the optimum temperature of LAMM decreased from 55°C to 50°C, the optimum pH value increased from 4.5 to 5.0, and the effects of Mn2+, Fe3+, Al3+, Co2+, Cr3+, and ethylenediaminetetraacetic acid (EDTA) on LAM enzyme activity before and after point mutation changed significantly. These findings help us better understanding the molecular mechanism of the interaction mechanism between SW and chLAM, and provide new reference for solving locoweeds poisoning.
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Affiliation(s)
- Yan Wang
- Department of Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Jiang-Ye Zhang
- Department of Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Jun-Yang Teng
- Department of Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Hao-Fei Xiong
- Department of Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Qin-Fan Li
- Department of Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, China
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Alpha-mannosidosis in Tunisian consanguineous families: Potential involvement of variants in GHR and SLC19A3 genes in the variable expressivity of cognitive impairment. PLoS One 2021; 16:e0258202. [PMID: 34614013 PMCID: PMC8494324 DOI: 10.1371/journal.pone.0258202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 09/21/2021] [Indexed: 01/30/2023] Open
Abstract
Alpha-Mannosidosis (AM) is an ultra-rare storage disorder caused by a deficiency of lysosomal alpha-mannosidase encoded by the MAN2B1 gene. Clinical presentation of AM includes mental retardation, recurrent infections, hearing loss, dysmorphic features, and motor dysfunctions. AM has never been reported in Tunisia. We report here the clinical and genetic study of six patients from two Tunisian families with AM. The AM diagnosis was confirmed by an enzymatic activity assay. Genetic investigation was conducted by Sanger sequencing of the mutational hotspots for the first family and by ES analysis for the second one. In the first family, a frameshift duplication p.(Ser802GlnfsTer129) was identified in the MAN2B1 gene. For the second family, ES analysis led to the identification of a missense mutation p.(Arg229Trp) in the MAN2B1 gene in four affected family members. The p.(Ser802GlnfsTer129) mutation induces a premature termination codon which may trigger RNA degradation by the NMD system. The decrease in the levels of MAN2B1 synthesis could explain the severe phenotype observed in the index case. According to the literature, the p.(Arg229Trp) missense variant does not have an impact on MAN2B1 maturation and transportation, which correlates with a moderate clinical sub-type. To explain the intra-familial variability of cognitive impairment, exome analysis allowed the identification of two likely pathogenic variants in GHR and SLC19A3 genes potentially associated to cognitive decline. The present study raises awareness about underdiagnosis of AM in the region that deprives patients from accessing adequate care. Indeed, early diagnosis is critical in order to prevent disease progression and to propose enzyme replacement therapy.
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Wiesinger T, Schwarz M, Mechtler TP, Liebmann-Reindl S, Streubel B, Kasper DC. α-Mannosidosis - An underdiagnosed lysosomal storage disease in individuals with an 'MPS-like' phenotype. Mol Genet Metab 2020; 130:149-152. [PMID: 32331969 DOI: 10.1016/j.ymgme.2020.04.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/06/2020] [Accepted: 04/06/2020] [Indexed: 12/21/2022]
Abstract
Individuals affected by alpha-Mannosidosis suffer from similar clinical symptoms such as respiratory infections, skeletal changes as patients with mucopolysaccharidoses (MPS). α-Mannosidosis is considered as an ultra-rare disorders and also diagnostic testing is often limited. With the availability of novel therapies and easy-to-access diagnostic tests (e.g. Tandem mass spectrometry) using dried blood spots for both enzymatic and genetic testing, the chance for the development of a better understanding of disease and awareness may be triggered. In a pilot study, we have investigated 1010 residual dried blood spot samples from individuals suspicious to MPS. In these study cohort, 158/1010 individuals were genetically confirmed for MPS. Additional biochemical and genetic confirmatory testing for α-mannosidases revealed four individuals with a final diagnosis of α-mannosidosis. This unexpected high number of individuals with α-mannosidosis demonstrated the urgent need of taking this rare disorder in clinical and diagnostic consideration particularly in patients suspicious to MPS.
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Affiliation(s)
- Thomas Wiesinger
- ARCHIMED Life Science GmbH, Leberstraße 20, 1110 Vienna, Austria.
| | - Markus Schwarz
- ARCHIMED Life Science GmbH, Leberstraße 20, 1110 Vienna, Austria
| | | | | | - Berthold Streubel
- Department of Pathology, The Medical University of Vienna, 1090 Vienna, Austria
| | - David C Kasper
- ARCHIMED Life Science GmbH, Leberstraße 20, 1110 Vienna, Austria.
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Rísquez-Cuadro R, Matsumoto R, Ortega-Caballero F, Nanba E, Higaki K, García Fernández JM, Ortiz Mellet C. Pharmacological Chaperones for the Treatment of α-Mannosidosis. J Med Chem 2019; 62:5832-5843. [PMID: 31017416 DOI: 10.1021/acs.jmedchem.9b00153] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
α-Mannosidosis (AM) results from deficient lysosomal α-mannosidase (LAMAN) activity and subsequent substrate accumulation in the lysosome, leading to severe pathology. Many of the AM-causative mutations compromise enzyme folding and could be rescued with purpose-designed pharmacological chaperones (PCs). We found that PCs combining a LAMAN glycone-binding motif based on the 5 N,6 O-oxomethylidenemannojirimycin (OMJ) glycomimetic core and different aglycones, in either mono- or multivalent displays, elicit binding modes involving glycone and nonglycone enzyme regions that reinforce the protein folding and stabilization potential. Multivalent derivatives exhibited potent enzyme inhibition that generally prevailed over the chaperone effect. On the contrary, monovalent OMJ derivatives with LAMAN aglycone binding area-fitting substituents proved effective as activity enhancers for several mutant LAMAN forms in AM patient fibroblasts and/or transfected MAN2 B1-KO cells. This translated into a significant improvement in endosomal/lysosomal function, reverting not only the primary LAMAN substrate accumulation but also the additional downstream consequences such as cholesterol accumulation.
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Affiliation(s)
- Rocío Rísquez-Cuadro
- Department of Organic Chemistry, Faculty of Chemistry , University of Sevilla , C/ Profesor García González 1 , 41012 Sevilla , Spain
| | - Reimi Matsumoto
- Organization for Research Initiative and Promotion , Tottori University , 86 Nishi-cho , Yonago 683-8503 , Japan
| | - Fernando Ortega-Caballero
- Department of Organic Chemistry, Faculty of Chemistry , University of Sevilla , C/ Profesor García González 1 , 41012 Sevilla , Spain
| | - Eiji Nanba
- Organization for Research Initiative and Promotion , Tottori University , 86 Nishi-cho , Yonago 683-8503 , Japan
| | - Katsumi Higaki
- Organization for Research Initiative and Promotion , Tottori University , 86 Nishi-cho , Yonago 683-8503 , Japan
| | - José Manuel García Fernández
- Instituto de Investigaciones Químicas (IIQ) , CSIC-Universidad de Sevilla , Avda. Américo Vespucio 49, Isla de la Cartuja , 41092 Sevilla , Spain
| | - Carmen Ortiz Mellet
- Department of Organic Chemistry, Faculty of Chemistry , University of Sevilla , C/ Profesor García González 1 , 41012 Sevilla , Spain
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Damme M, Stroobants S, Lüdemann M, Rothaug M, Lüllmann-Rauch R, Beck HC, Ericsson A, Andersson C, Fogh J, D'Hooge R, Saftig P, Blanz J. Chronic enzyme replacement therapy ameliorates neuropathology in alpha-mannosidosis mice. Ann Clin Transl Neurol 2015; 2:987-1001. [PMID: 26817023 PMCID: PMC4693626 DOI: 10.1002/acn3.245] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 08/03/2015] [Accepted: 08/03/2015] [Indexed: 01/17/2023] Open
Abstract
OBJECTIVE The lysosomal storage disease alpha-mannosidosis is caused by the deficiency of the lysosomal acid hydrolase alpha-mannosidase (LAMAN) leading to lysosomal accumulation of neutral mannose-linked oligosaccharides throughout the body, including the brain. Clinical findings in alpha-mannosidosis include skeletal malformations, intellectual disabilities and hearing impairment. To date, no curative treatment is available. We previously developed a beneficial enzyme replacement therapy (ERT) regimen for alpha-mannosidase knockout mice, a valid mouse model for the human disease. However, humoral immune responses against the injected recombinant human alpha-mannosidase (rhLAMAN) precluded long-term studies and chronic treatment. METHODS Here, we describe the generation of an immune-tolerant alpha-mannosidosis mouse model that allowed chronic injection of rhLAMAN by transgenic expression of a catalytically inactive variant of human LAMAN in the knockout background. RESULTS Chronic ERT of rhLAMAN revealed pronounced effects on primary substrate storage throughout the brain, normalization of lysosomal enzyme activities and morphology as well as a decrease in microglia activation. The positive effect of long-term ERT on neuronal lysosomal function was reflected by an improvement of cognitive deficits and exploratory activity. in vivo and in vitro uptake measurements indicate rapid clearance of rhLAMAN from circulation and a broad uptake into different cell types of the nervous system. INTERPRETATION Our data contribute to the understanding of neurological disorders treatment by demonstrating that lysosomal enzymes such as rhLAMAN can penetrate into the brain and is able to ameliorate neuropathology.
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Affiliation(s)
- Markus Damme
- Biochemical Institute University of Kiel D-24098 Kiel Germany
| | - Stijn Stroobants
- Laboratory of Biological Psychology University of Leuven B-3000 Leuven Belgium
| | - Meike Lüdemann
- Biochemical Institute University of Kiel D-24098 Kiel Germany
| | | | | | - Hans Christian Beck
- Department of Biochemistry and Pharmacology Centre for Clinical Proteomics Odense University Hospital Sdr Boulevard 29 DK-5000 Odense C Denmark
| | | | | | - Jens Fogh
- Zymenex A/S Roskildevej 12C 3400 Hillerød Denmark
| | - Rudi D'Hooge
- Laboratory of Biological Psychology University of Leuven B-3000 Leuven Belgium
| | - Paul Saftig
- Biochemical Institute University of Kiel D-24098 Kiel Germany
| | - Judith Blanz
- Biochemical Institute University of Kiel D-24098 Kiel Germany
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Borgwardt L, Stensland HMFR, Olsen KJ, Wibrand F, Klenow HB, Beck M, Amraoui Y, Arash L, Fogh J, Nilssen Ø, Dali CI, Lund AM. Alpha-mannosidosis: correlation between phenotype, genotype and mutant MAN2B1 subcellular localisation. Orphanet J Rare Dis 2015; 10:70. [PMID: 26048034 PMCID: PMC4465300 DOI: 10.1186/s13023-015-0286-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 05/19/2015] [Indexed: 12/01/2022] Open
Abstract
Background Alpha-mannosidosis is caused by mutations in MAN2B1, leading to loss of lysosomal alpha-mannosidase activity. Symptoms include intellectual disabilities, hearing impairment, motor function disturbances, facial coarsening and musculoskeletal abnormalities. Methods To study the genotype-phenotype relationship for alpha-mannosidosis 66 patients were included. Based on the predicted effect of the mutations and the subcellular localisation of mutant MAN2B1 in cultured cells, the patients were divided into three subgroups. Clinical and biochemical data were collected. Correlation analyses between each of the three subgroups of genotype/subcellular localisation and the clinical and biochemical data were done to investigate the potential relationship between genotype and phenotype in alpha-mannosidosis. Statistical analyses were performed using the SPSS software. Analyses of covariance were performed to describe the genotype-phenotype correlations. The phenotype parameters were modelled by the mutation group and age as a covariate. P values of <0.05 were considered as statistically significant. Results Complete MAN2B1 genotypes were established for all patients. We found significantly higher scores in the Leiter-R test, lower concentrations of CSF-oligosaccharides, higher point scores in the Bruininks-Oseretsky Test of Motor Proficiency subtests (BOT-2); Upper limb coordination and Balance, and a higher FVC% in patients in subgroup 3, harbouring at least one variant that allows localisation of the mutant MAN2B1 protein to the lysosomes compared to subgrou 2 and/or subgroup 1 with no lysosomal localization of the mutant MAN2B1 protein. Conclusion Our results indicate a correlation between the MAN2B1 genotypes and the cognitive function, upper limb coordination, balance, FVC% and the storage of oligosaccharides in CSF. This correlation depends on the subcellular localisation of the mutant MAN2B1 protein.
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Affiliation(s)
- Line Borgwardt
- Department of Clinical Genetics, Centre for Inherited Metabolic Diseases, Copenhagen University Hospital Rigshospitalet, 9 Blegdamsvej, 2100, Copenhagen, Denmark.
| | | | | | - Flemming Wibrand
- Department of Clinical Genetics, Centre for Inherited Metabolic Diseases, Copenhagen University Hospital Rigshospitalet, 9 Blegdamsvej, 2100, Copenhagen, Denmark.
| | - Helle Bagterp Klenow
- Department of Medical Genetics, Division of Child and Adolescent Health, University Hospital of North Norway, Tromsø, Norway.
| | - Michael Beck
- Zentrum für Kinder - und Jugendmedizin, Villa Metabolica, Mainz, Germany.
| | - Yasmina Amraoui
- Zentrum für Kinder - und Jugendmedizin, Villa Metabolica, Mainz, Germany.
| | - Laila Arash
- Zentrum für Kinder - und Jugendmedizin, Villa Metabolica, Mainz, Germany.
| | - Jens Fogh
- Zymenex A/S (Chiesi Group), Hilleroed, Denmark.
| | - Øivind Nilssen
- Department of Medical Genetics, Division of Child and Adolescent Health, University Hospital of North Norway, Tromsø, Norway. .,Department of Clinical Medicine, Medical Genetics, University of North Norway, Tromsø, Norway.
| | - Christine I Dali
- Department of Clinical Genetics, Centre for Inherited Metabolic Diseases, Copenhagen University Hospital Rigshospitalet, 9 Blegdamsvej, 2100, Copenhagen, Denmark.
| | - Allan Meldgaard Lund
- Department of Clinical Genetics, Centre for Inherited Metabolic Diseases, Copenhagen University Hospital Rigshospitalet, 9 Blegdamsvej, 2100, Copenhagen, Denmark.
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Riise Stensland HMF, Frantzen G, Kuokkanen E, Buvang EK, Klenow HB, Heikinheimo P, Malm D, Nilssen Ø. amamutdb.no: A relational database for MAN2B1 allelic variants that compiles genotypes, clinical phenotypes, and biochemical and structural data of mutant MAN2B1 in α-mannosidosis. Hum Mutat 2015; 36:581-6. [PMID: 25762455 DOI: 10.1002/humu.22787] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 02/13/2015] [Indexed: 01/22/2023]
Abstract
α-Mannosidosis is an autosomal recessive lysosomal storage disorder caused by mutations in the MAN2B1 gene, encoding lysosomal α-mannosidase. The disorder is characterized by a range of clinical phenotypes of which the major manifestations are mental impairment, hearing impairment, skeletal changes, and immunodeficiency. Here, we report an α-mannosidosis mutation database, amamutdb.no, which has been constructed as a publicly accessible online resource for recording and analyzing MAN2B1 variants (http://amamutdb.no). Our aim has been to offer structured and relational information on MAN2B1 mutations and genotypes along with associated clinical phenotypes. Classifying missense mutations, as pathogenic or benign, is a challenge. Therefore, they have been given special attention as we have compiled all available data that relate to their biochemical, functional, and structural properties. The α-mannosidosis mutation database is comprehensive and relational in the sense that information can be retrieved and compiled across datasets; hence, it will facilitate diagnostics and increase our understanding of the clinical and molecular aspects of α-mannosidosis. We believe that the amamutdb.no structure and architecture will be applicable for the development of databases for any monogenic disorder.
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Affiliation(s)
| | | | - Elina Kuokkanen
- Department of Biochemistry, University of Turku, Turku, Finland
| | - Elisabeth Kjeldsen Buvang
- Department of Clinical Medicine-Medical Genetics, University of Tromsø-The Arctic University of Norway, Tromsø, Norway
| | - Helle Bagterp Klenow
- Division of Child and Adolescent Health, Department of Medical Genetics, University Hospital of North Norway, Tromsø, Norway
| | | | - Dag Malm
- The Tromsø Internal Medicine Specialist Center, Tromsø, Norway
| | - Øivind Nilssen
- Division of Child and Adolescent Health, Department of Medical Genetics, University Hospital of North Norway, Tromsø, Norway.,Department of Clinical Medicine-Medical Genetics, University of Tromsø-The Arctic University of Norway, Tromsø, Norway
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De Marchis F, Bellucci M, Pompa A. Traffic of human α-mannosidase in plant cells suggests the presence of a new endoplasmic reticulum-to-vacuole pathway without involving the Golgi complex. PLANT PHYSIOLOGY 2013; 161:1769-82. [PMID: 23449646 PMCID: PMC3613454 DOI: 10.1104/pp.113.214536] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 02/28/2013] [Indexed: 05/08/2023]
Abstract
The transport of secretory proteins from the endoplasmic reticulum to the vacuole requires sorting signals as well as specific transport mechanisms. This work is focused on the transport in transgenic tobacco (Nicotiana tabacum) plants of a human α-mannosidase, MAN2B1, which is a lysosomal enzyme involved in the turnover of N-linked glycoproteins and can be used in enzyme replacement therapy. Although ubiquitously expressed, α-mannosidases are targeted to lysosomes or vacuoles through different mechanisms according to the organisms in which these proteins are produced. In tobacco cells, MAN2B1 reaches the vacuole even in the absence of mannose-6-phosphate receptors, which are responsible for its transport in animal cells. We report that MAN2B1 is targeted to the vacuole without passing through the Golgi complex. In addition, a vacuolar targeting signal that is recognized in plant cells is located in the MAN2B1 amino-terminal region. Indeed, when this amino-terminal domain is removed, the protein is retained in the endoplasmic reticulum. Moreover, when this domain is added to a plant-secreted protein, the resulting fusion protein is partially redirected to the vacuole. These results strongly suggest the existence in plants of a new type of vacuolar traffic that can be used by leaf cells to transport vacuolar proteins.
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Affiliation(s)
- Francesca De Marchis
- Istituto di Genetica Vegetale, Consiglio Nazionale delle Ricerche, 06128 Perugia, Italy
| | - Michele Bellucci
- Istituto di Genetica Vegetale, Consiglio Nazionale delle Ricerche, 06128 Perugia, Italy
| | - Andrea Pompa
- Istituto di Genetica Vegetale, Consiglio Nazionale delle Ricerche, 06128 Perugia, Italy
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Identification of 83 novel alpha-mannosidosis-associated sequence variants: Functional analysis of MAN2B1 missense mutations. Hum Mutat 2012; 33:511-20. [DOI: 10.1002/humu.22005] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 11/28/2011] [Indexed: 12/14/2022]
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De Marchis F, Balducci C, Pompa A, Riise Stensland HMF, Guaragno M, Pagiotti R, Menghini AR, Persichetti E, Beccari T, Bellucci M. Human α-mannosidase produced in transgenic tobacco plants is processed in human α-mannosidosis cell lines. PLANT BIOTECHNOLOGY JOURNAL 2011; 9:1061-73. [PMID: 21645202 DOI: 10.1111/j.1467-7652.2011.00630.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Deficiency in human lysosomal α-mannosidase (MAN2B1) results in α-mannosidosis, a lysosomal storage disorder; patients present a wide range of neurological, immunological, and skeletal symptoms caused by a multisystemic accumulation of mannose-containing oligosaccharides. Here, we describe the expression of recombinant MAN2B1 both transiently in Nicotiana benthamiana leaves and in the leaves and seeds of stably transformed N. tabacum plants. After purification from tobacco leaves, the recombinant enzyme was found to be N-glycosylated and localized in vacuolar compartments. In the fresh leaves of tobacco transformants, MAN2B1 was measured at 10,200 units/kg, and the purified enzyme from these leaves had a specific activity of 32-45 U/mg. Furthermore, tobacco-produced MAN2B1 was biochemically similar to the enzyme purified from human tissues, and it was internalized and processed by α-mannosidosis fibroblast cells. These results strongly indicate that plants can be considered a promising expression system for the production of recombinant MAN2B1 for use in enzyme replacement therapy.
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Affiliation(s)
- Francesca De Marchis
- Institute of Plant Genetics, Italian National Council of Research (CNR), Perugia, Italy
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Kuokkanen E, Riise Stensland HMF, Smith W, Kjeldsen Buvang E, Van Nguyen L, Nilssen Ø, Heikinheimo P. Molecular and cellular characterization of novel α-mannosidosis mutations. Hum Mol Genet 2011; 20:2651-61. [DOI: 10.1093/hmg/ddr167] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Ultrastructural and functional abnormalities of mitochondria in cultivated fibroblasts from α-mannosidosis patients. Biologia (Bratisl) 2009. [DOI: 10.2478/s11756-009-0054-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Abstract
Alpha-mannosidosis is an inherited lysosomal storage disorder characterized by immune deficiency, facial and skeletal abnormalities, hearing impairment, and intellectual disability. It occurs in approximately 1 of 500,000 live births. The children are often born apparently normal, and their condition worsens progressively. Some children are born with ankle equinus or develop hydrocephalus in the first year of life. Main features are immune deficiency (manifested by recurrent infections, especially in the first decade of life), skeletal abnormalities (mild-to-moderate dysostosis multiplex, scoliosis and deformation of the sternum), hearing impairment (moderate-to-severe sensorineural hearing loss), gradual impairment of mental functions and speech, and often, periods of psychosis. Associated motor function disturbances include muscular weakness, joint abnormalities and ataxia. The facial trait include large head with prominent forehead, rounded eyebrows, flattened nasal bridge, macroglossia, widely spaced teeth, and prognathism. Slight strabismus is common. The clinical variability is significant, representing a continuum in severity. The disorder is caused by lysosomal alpha-mannosidase deficiency. Alpha-mannosidosis is inherited in an autosomal recessive fashion and is caused by mutations in the MAN2B1 gene located on chromosome 19 (19 p13.2-q12). Diagnosis is made by measuring acid alpha-mannosidase activity in leukocytes or other nucleated cells and can be confirmed by genetic testing. Elevated urinary secretion of mannose-rich oligosaccharides is suggestive, but not diagnostic. Differential diagnoses are mainly the other lysosomal storage diseases like the mucopolysaccharidoses. Genetic counseling should be given to explain the nature of the disease and to detect carriers. Antenatal diagnosis is possible, based on both biochemical and genetic methods. The management should be pro-active, preventing complications and treating manifestations. Infections must be treated frequently. Otolaryngological treatment of fluid in the middle ear is often required and use of hearing aids is invariably required. Early educational intervention for development of social skills is needed and physiotherapy is important to improve bodily function. Orthopedic surgery may be necessary. The long-term prognosis is poor. There is an insidiously slow progression of neuromuscular and skeletal deterioration over several decades, making most patients wheel-chair dependent. No patients manage to be completely socially independent. Many patients are over 50 years of age.
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