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1.
Front Mol Biosci ; 11: 1278955, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38481961

RESUMO

Extracellular vesicles (EVs), which are found in almost all cells and human body fluids, are currently being studied as a source of pathophysiological information. Previously, we demonstrated that at least two types of EVs can be isolated from human whole saliva (WS) using enzymatic activity of dipeptidyl peptidase IV (DPP IV) as a marker for differentiating the EV subsets. In the present study, EV fractions, termed EV-I 20 k-ppt and EV-II 100 k-ppt, were prepared by a combination of size-exclusion chromatography of improved condition and sequential centrifugation. The EV-I 20 k-ppt fraction contained medium/large EVs with a diameter of 100-1,000 nm, including aminopeptidase N (APN), mucin 1, ezrin, and Annexin A1. EV-II 100 k-ppt contained small EVs with a diameter of 20-70 nm, with DPP IV and CD9, programmed cell death 6-interacting protein, and tumor susceptibility gene 101 as characteristic proteins. Proteomic analyses also revealed distinctive repertoires of constituent proteins. Immunoprecipitation of several membrane proteins of the EVs with respective antibodies suggested their differential local membrane environment between the two types of salivary vesicles. Thus, we identified two distinctive types of EVs, one is APN/MUC1- rich EVs (EV-I, large/medium EVs) and the other is DPP IV/CD9-rich EVs (EV-II, small EVs). Furthermore, analysis of the binding of the EVs to coronavirus spike proteins showed that EV-II 100 k-ppt, but not EV-I 20 k-ppt, significantly bound to the spike protein of Middle East respiratory syndrome coronavirus (MERS-CoV). Finally, we developed a simple method to prepare two distinctive EVs from only 1 mL of human WS using sequential immunoprecipitation. Elucidating the features and functions of these two types of salivary EVs may help us understand their pathophysiological roles in the oral cavity and gastrointestinal tract.

2.
Nat Commun ; 13(1): 1847, 2022 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-35422047

RESUMO

Ribitol-phosphate modification is crucial for the functional maturation of α-dystroglycan. Its dysfunction is associated with muscular dystrophy, cardiomyopathy, and central nervous system abnormalities; however, no effective treatments are currently available for diseases caused by ribitol-phosphate defects. In this study, we demonstrate that prodrug treatments can ameliorate muscular dystrophy caused by defects in isoprenoid synthase domain containing (ISPD), which encodes an enzyme that synthesizes CDP-ribitol, a donor substrate for ribitol-phosphate modification. We generated skeletal muscle-selective Ispd conditional knockout mice, leading to a pathogenic reduction in CDP-ribitol levels, abnormal glycosylation of α-dystroglycan, and severe muscular dystrophy. Adeno-associated virus-mediated gene replacement experiments suggested that the recovery of CDP-ribitol levels rescues the ISPD-deficient pathology. As a prodrug treatment strategy, we developed a series of membrane-permeable CDP-ribitol derivatives, among which tetraacetylated CDP-ribitol ameliorated the dystrophic pathology. In addition, the prodrug successfully rescued abnormal α-dystroglycan glycosylation in patient fibroblasts. Consequently, our findings provide proof-of-concept for supplementation therapy with CDP-ribitol and could accelerate the development of therapeutic agents for muscular dystrophy and other diseases caused by glycosylation defects.


Assuntos
Distrofias Musculares , Pró-Fármacos , Animais , Humanos , Camundongos , Modelos Animais de Doenças , Distroglicanas , Músculo Esquelético , Distrofias Musculares/tratamento farmacológico , Distrofias Musculares/genética , Fosfatos , Pró-Fármacos/farmacologia , Pró-Fármacos/uso terapêutico , Ribitol/uso terapêutico
3.
J Biochem ; 170(2): 183-194, 2021 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-34255834

RESUMO

α-Dystroglycan (α-DG) is a highly glycosylated cell-surface protein. Defective O-mannosyl glycan on α-DG is associated with muscular dystrophies and cancer. In the biosynthetic pathway of the O-mannosyl glycan, fukutin (FKTN) and fukutin-related protein (FKRP) transfer ribitol phosphate (RboP). Previously, we reported that FKTN and FKRP can also transfer glycerol phosphate (GroP) from CDP-glycerol (CDP-Gro) and showed the inhibitory effects of CDP-Gro on functional glycan synthesis by preventing glycan elongation in vitro. However, whether mammalian cells have CDP-Gro or associated synthetic machinery has not been elucidated. Therefore, the function of CDP-Gro in mammals is largely unknown. Here, we reveal that cultured human cells and mouse tissues contain CDP-Gro using liquid chromatography tandem-mass spectrometry (LC-MS/MS). By performing the enzyme activity assay of candidate recombinant proteins, we found that ethanolamine-phosphate cytidylyltransferase (PCYT2), the key enzyme in de novo phosphatidylethanolamine biosynthesis, has CDP-Gro synthetic activity from glycerol-3-phosphate (Gro3P) and CTP. In addition, knockdown of PCYT2 dramatically reduced cellular CDP-Gro. These results indicate that PCYT2 is a CDP-Gro synthase in mammals. Furthermore, we found that the expression of functionally glycosylated α-DG is increased by reducing PCYT2 expression. Our results suggest an important role for CDP-Gro in the regulation of α-DG function in mammals.


Assuntos
Distroglicanas/metabolismo , Açúcares de Nucleosídeo Difosfato/metabolismo , RNA Nucleotidiltransferases/metabolismo , Animais , Cromatografia Líquida/métodos , Cistina Difosfato/metabolismo , Glicerol/metabolismo , Glicosilação , Células HEK293 , Humanos , Masculino , Mamíferos , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Pentosiltransferases/metabolismo , Fosfatidiletanolaminas/metabolismo , Monoéster Fosfórico Hidrolases/metabolismo , Polissacarídeos/metabolismo , Espectrometria de Massas em Tandem/métodos
4.
Geriatr Gerontol Int ; 21(8): 601-613, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34212470

RESUMO

BACKGROUND: As Japan's population continues to age, it is estimated that the number of people aged ≥75 years will exceed 20 million by 2025. Furthermore, over the past 10 years, we have not reduced the difference between life expectancy and healthy life expectancy. Therefore, the extension of healthy life expectancy and the development of a healthy society are the most urgent issues. In terms of medical care, the changing times have inevitably led to changes in disease structures and medical demands; therefore, the medical delivery system has had to be changed to meet these demands. As dementia rapidly increases, it is important to address "frailty," a condition in which people become more vulnerable to environmental factors as they age, and there is a need to provide services to older people, particularly the old-old, that emphasize quality of life in addition to medical care. To realize a super-aged society that will remain vigorous and vibrant for many years, we need to rethink the future of Japanese medicine and healthcare, and the state of society. CURRENT SITUATION AND PROBLEMS: Disparity between healthy life expectancy and average life expectancy in the realization of a healthy society It is a challenge to build a society with a long and healthy life expectancy through comprehensive prevention and management of lifestyle-related diseases, as well as the elucidation of the factors that explain sex differences in healthy life expectancy, based on the recognition that lifestyle-related diseases in midlife are risk factors for frailty and dementia in old age. Challenges in medical care for building a super-aged and healthy society The challenges include promoting clinical guidelines suitable for older people, including lifestyle-related disease management, promoting comprehensive research on aging (basic research, clinical research and community collaboration research), and embodying a paradigm shift from "cure-seeking medical care" to "cure- and support-seeking medical care." Furthermore, the key to the future of integrated community care is the development of a comprehensive medical care system for older people in each region and the development of the next generation of medical personnel. Dissemination of frailty prevention measures in a super-aged society The concept of frailty encompasses the meaning of multifacetedness and reversibility; therefore, a comprehensive approach is required, including the renewal of conventional prevention activities in each region, such as the nutritional status of older people, physical activity including exercise, and various opportunities for social participation and participation conditions. Challenges of an unstable diet and undernutrition in older people According to the National Health and Nutrition Examination Survey of Japan, energy and protein intakes are low in Japanese people aged ≥75 years; particularly in people aged ≥80 years, low and insufficient intake of nutrients are prominent. Undernutrition in older people is increasing and is more pronounced in women. There are multiple factors behind this, including social factors, such as living alone, eating alone, poverty and other social factors, as well as problems with access to food security. Pharmacotherapy for older people: measures against polypharmacy In addition to the problems of adverse drug events, drug interactions, duplication of effects and the presence of drugs that "require particularly careful administration," it is also necessary to take measures against polypharmacy in older people, as well as medical economic issues, such as high drug costs and large amounts of remaining drugs. Barriers to this measure include multiple medical institution visits for each disease, lack of coordination between professions, and lack of understanding by patients and families. Role of local communities in a healthy society The decline in the working-age population is also a major challenge; however, we need to make a shift to use this declining birthrate and aging population as an opportunity rather than a crisis. As we look ahead to the coming of the 100-year age of life, we rethink the creation of a comprehensive society and community, and aim to create an age-free society where everyone can play an active role and live in peace, regardless of age. CONTENTS OF THE PROPOSAL: In this report, we have put together a vision for the future of an aging Japanese society from a broader perspective of how the environment and local communities should be, rather than simply from the perspective of individual health. We aim to convey this proposal to the Ministry of Health, Labor and Welfare, the Ministry of Education, Culture, Sports, Science and Technology, the Cabinet Office, and various professional organizations. The paradigm shift from "cure-seeking medical care" to "cure- and support-seeking medical care" should be promoted for the development of a healthy society While further promoting pre-emptive medical care in the medical care for older people, the development of multidisciplinary medical guidelines appropriate for older people should be promoted at the same time. In addition, we should promote basic aging research, clinical research (including the long-term care field) and transitional research that cover regional areas. Furthermore, while promoting the paradigm shift from "cure-seeking medical care" to "cure- and support-seeking medical care," the development of various comprehensive medical treatment systems for older people and the strengthening of integrated community care systems should be promoted. Development of the next generation of medical personnel to comprehensively deal with geriatric care, including training geriatric specialists, should be promoted As the number of older people with multimorbidities and frailty rapidly increases in the future, we should promote the development of the next generation of medical personnel who can comprehensively handle medical care for older people, including training leading geriatricians in cooperation with multiple professions in the integrated community care system to provide sufficient medical care. Countermeasures for frailty in older people should be promoted from medical and community planning perspectives To address frailty, which requires comprehensive evaluation and intervention, the three pillars of frailty prevention (nutrition, exercise and social participation) should be incorporated and addressed as part of community development within each municipality, taking into account local characteristics. In particular, it is necessary to revise the way of thinking about nutrition management in older people and the guidelines of the societies in the field. In addition, it is important to strengthen industry-academia-government-private partnerships in each region, taking into account not only medical issues, but also social factors, and encourage the development of momentum in the entire region regarding measures against undernutrition in older people. Polypharmacy measures should be promoted in pharmacotherapy for older people It is necessary to promote cooperation between physicians and pharmacists, establish other multiprofessional cooperation systems, and develop medical and long-term care insurance systems to support this. It is also essential to change the public's mindset, and awareness-raising activities at all levels are required, including the enhancement of educational materials for medical caregivers and the general public. In addition, the economic impact of healthcare using big data should be timely clarified. Innovation in medical and urban planning perspectives should be promoted In the future, it will be necessary to modify and update multidisciplinary approaches such as social participation (e.g. participation in a salon) with a view to innovation in both medical care and community development, especially on the idea of a symbiotic community. In addition, industry-academia-government-private partnership is necessary, including all aforementioned, such as places where people can play an active role in the rest of their lives (such as employment), promotion of human connections, promotion of technology to support older people and support for daily life. Geriatr Gerontol Int 2021; 21: 601-613.


Assuntos
Preparações Farmacêuticas , Qualidade de Vida , Idoso , Feminino , Humanos , Japão , Masculino , Inquéritos Nutricionais , Sociedades
5.
Methods Mol Biol ; 2132: 609-619, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32306360

RESUMO

Protein O-mannose ß1,2-N-acetylglucosaminyltransferase 1 (POMGNT1) is one of the gene products responsible for α-dystroglycanopathy, which is a type of congenital muscular dystrophy caused by O-mannosyl glycan defects. The originally identified function of POMGNT1 was as a glycosyltransferase that catalyzes the formation of the GlcNAcß1-2Man linkage of O-mannosyl glycan, but the enzyme function is not essential for α-dystroglycanopathy pathogenesis. Our recent study revealed that the stem domain of POMGNT1 has a carbohydrate-binding ability, which recognizes the GalNAcß1-3GlcNAc structure. This carbohydrate-binding activity is required for the formation of the ribitol phosphate (RboP)-3GalNAcß1-3GlcNAc structure by fukutin. This protocol describes methods to assess the carbohydrate-binding activity of the POMGNT1 stem domain.


Assuntos
Carboidratos/farmacologia , N-Acetilglucosaminiltransferases/química , N-Acetilglucosaminiltransferases/metabolismo , Clonagem Molecular , Cristalografia por Raios X , Citocinas/química , Humanos , N-Acetilglucosaminiltransferases/genética , Proteínas de Neoplasias/química , Domínios Proteicos/efeitos dos fármacos
6.
J Biochem ; 167(5): 483-493, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31951006

RESUMO

The deficiency of α-Klotho in mice causes phenotypes resembling human age-associated disorders at 3-4 weeks after birth and shows short lifespans of ∼2 months. One of the crucial symptoms is pulmonary emphysema, although α-Klotho is not expressed in the lungs. α-Klotho secreted from the kidneys is probably involved in the pathology of emphysema because kidney-specific knockout mice exhibit emphysematous structural changes. We examined whether any glycan changes in α-Klotho mouse lungs were observed, because α-Klotho is reported to have glycosidase activity. Here, we found the accumulation of heparan sulphate in the microsomal fraction of α-Klotho mouse lungs. Meanwhile, a disintegrin and metalloproteinase 17 (ADAM17) expression was decreased in α-Klotho mice. From these results, it is thought that the increase in heparan sulphate is due to insufficient cleavage of the core protein by ADAM17. Additionally, a reduction in α-Klotho and a decline of ADAM17 were also observed both in normal aged mice and in senescence marker protein-30 (SMP30) knockout mice, a mouse model of premature ageing. Thus, the decrease in ADAM17 is caused by the reduction in α-Klotho. These may be involved in the deterioration of lung function during ageing and may be associated with the pathology of pulmonary emphysema.


Assuntos
Proteína ADAM17/genética , Glucuronidase/deficiência , Pulmão/metabolismo , Proteína ADAM17/metabolismo , Animais , Proteínas de Ligação ao Cálcio/deficiência , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Regulação para Baixo , Feminino , Glucuronidase/metabolismo , Heparitina Sulfato/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/deficiência , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas Klotho , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos
7.
Geriatr Gerontol Int ; 19(10): 1054-1062, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31436032

RESUMO

AIM: Human vascular senescence, which mainly occurs in media, is not completely understood. Here, we used proteomic approaches to investigate age-associated changes in human aortic media with the goal of understanding the molecular mechanisms underlying vascular senescence. METHOD: Cryopreserved autopsy samples of aortic media from older-aged (aged 70-100 years, n = 25), middle-aged (aged 49-68 years, n = 24), and young (aged 21-39 years, n = 12) subjects were collected. We used two proteomic techniques, two-dimensional differential gel electrophoresis and isobaric tags for relative and absolute quantitation, and we subjected differentially-expressed proteins among age groups to immunohistochemical analyses. RESULTS: Proteomic analyses showed that the expression of lactadherin, which produces medin, was elevated in aortic media of older-aged individuals. Immunohistochemical and Congo red staining showed that lactadherin and apolipoprotein E were deposited, and that amyloidosis was enhanced in older-aged aortic media. Furthermore, the markers of oxidative damage (8-hydroxy-2'-deoxyguanosine and 4-hydroxy-2-nonenal) were significantly elevated in aortic media of middle-aged or older-aged individuals. The immunohistochemical expression of anti-oxidant proteins (thioredoxin and extracellular superoxide dismutase) was also high in middle-aged and older-aged groups. Oxidative damage might induce the disruption of smooth muscle cells, resulting in the decrement of α-actin, a highly-expressed protein in smooth muscle cells, and matrix remodeling, in which several proteins associated with extracellular matrix were altered with aging. CONCLUSIONS: Proteomic approaches showed that the elevated expression of lactadherin might contribute to amyloid deposition, enhancement of oxidative stress, induction of antioxidant proteins and matrix remodeling in older-aged aortic media. Geriatr Gerontol Int 2019; 19: 1054-1062.


Assuntos
Envelhecimento/metabolismo , Antígenos de Superfície/metabolismo , Aorta/metabolismo , Proteínas do Leite/metabolismo , Proteoma/metabolismo , Actinas/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/genética , Amiloide/metabolismo , Apolipoproteínas E/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Miócitos de Músculo Liso/citologia , Miócitos de Músculo Liso/metabolismo , Proteoma/genética , Superóxido Dismutase/metabolismo , Tiorredoxinas/metabolismo , Adulto Jovem
8.
Sci Rep ; 9(1): 4023, 2019 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-30858535

RESUMO

Inflammation is a critical feature of aging and its related diseases, including cardiovascular diseases. Recent epidemiological studies demonstrated that abdominal aortic aneurysm (AAA), an aging-related vascular pathological condition, is associated with cognitive decline. However, the underlying mechanism, especially the role of vascular inflammation, is largely unknown because of lack of an available animal model. In this study, we examined whether vascular inflammation affects synaptic and cognitive dysfunction, using an AAA mouse model. In young (3 months) and middle-aged (12 months) C57BL/6J mice, AAA was induced by angiotensin II infusion with calcium chloride application. After 4 weeks of induction, aortic diameter was significantly increased and excessive Mac3-positive inflammatory cells infiltrated the destroyed aorta in middle-aged mice. AAA-induced middle-aged mice further exhibited cognitive impairment. Neuronal loss was observed in the CA3 region of the hippocampus. IBA1/MHCII-double-positive microglia activation was also seen in the hippocampus, suggesting that vascular inflammation drives neuroinflammation and subsequent cognitive dysfunction. Furthermore, we found that senescence-accelerated mice prone 8 exhibited robust AAA formation and a marked decrease of cognitive and synaptic function in the hippocampus mediated by inflammation. In conclusion, this novel murine model convincingly suggested the occurrence of vascular inflammation-derived cognitive dysfunction.


Assuntos
Aneurisma da Aorta Abdominal/complicações , Aneurisma da Aorta Abdominal/patologia , Disfunção Cognitiva/etiologia , Modelos Animais de Doenças , Inflamação/etiologia , Camundongos Endogâmicos C57BL , Envelhecimento/patologia , Angiotensina II , Animais , Antígenos de Diferenciação/imunologia , Aorta Abdominal/imunologia , Aorta Abdominal/patologia , Aneurisma da Aorta Abdominal/induzido quimicamente , Cloreto de Cálcio , Proteínas de Ligação ao Cálcio/imunologia , Disfunção Cognitiva/patologia , Genes MHC da Classe II/imunologia , Hipocampo/patologia , Inflamação/patologia , Ativação de Macrófagos , Masculino , Camundongos , Proteínas dos Microfilamentos/imunologia , Microglia/patologia
9.
Biochim Biophys Acta Gen Subj ; 1862(6): 1462-1471, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29580922

RESUMO

BACKGROUND: Glycosylation is highly susceptible to changes of the physiological conditions, and accordingly, is a potential biomarker associated with several diseases and/or longevity. Semi-supercentenarians (SSCs; older than 105 years) are thought to be a model of human longevity. Thus, we performed glycoproteomics using plasma samples of SSCs, and identified proteins and conjugated N-glycans that are characteristic of extreme human longevity. METHODS: Plasma proteins from Japanese semi-supercentenarians (SSCs, 106-109 years), aged controls (70-88 years), and young controls (20-38 years) were analysed by using lectin microarrays and liquid chromatography/mass spectrometry (LC/MS). Peak area ratios of glycopeptides to corresponding normalising peptides were subjected to orthogonal projections to latent structures discriminant analysis (OPLS-DA). Furthermore, plasma levels of clinical biomarkers were measured. RESULTS: We found two lectins such as Phaseolus vulgaris, and Erythrina cristagalli (ECA), of which protein binding were characteristically increased in SSCs. Peak area ratios of ECA-enriched glycopeptides were successfully discriminated between SSCs and controls using OPLS-DA, and indicated that tri-antennary and sialylated N-glycans of haptoglobin at Asn207 and Asn211 sites were characterized in SSCs. Sialylated glycans of haptoglobin are a potential biomarker of several diseases, such as hepatocellular carcinoma, liver cirrhosis, and IgA-nephritis. However, the SSCs analysed here did not suffer from these diseases. CONCLUSIONS: Tri-antennary and sialylated N-glycans on haptoglobin at the Asn207 and Asn211 sites were abundant in SSCs and characteristic of extreme human longevity. GENERAL SIGNIFICANCE: We found abundant glycans in SSCs, which may be associated with human longevity.


Assuntos
Biomarcadores/sangue , Proteínas Sanguíneas/metabolismo , Glicopeptídeos/sangue , Glicoproteínas/sangue , Longevidade/fisiologia , Polissacarídeos/sangue , Proteômica/métodos , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Feminino , Glicosilação , Humanos , Adulto Jovem
10.
Biochim Biophys Acta Mol Cell Res ; 1865(6): 874-888, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29567213

RESUMO

Macrophages secrete endoplasmic reticulum aminopeptidase 1 (ERAP1) in response to lipopolysaccharide (LPS) and interferon (IFN)-γ to enhance their phagocytic and nitric oxide (NO) synthetic activities. In this study, we found that a subset of secreted ERAP1 bound to exosomes released from LPS/IFN-γ-treated murine RAW264.7 macrophages compared to untreated cells. ERAP1-bound exosomes enhanced phagocytic and NO synthetic activities of macrophages more efficiently than free ERAP1 and exosomes derived from untreated cells. Deletion of the exon 10 coding sequence in ERAP1 gene resulted in loss of binding to exosomes. By comparing the activities of exosomes derived from wild-type and ERAP1 gene-deficient RAW264.7 cells, we observed that ERAP1 contributed to the exosome-dependent phagocytosis and NO synthesis of the cells. Upon stimulation of RAW264.7 cells with LPS/IFN-γ, TNF-α, IFN-γ, and CCL3 were also associated with the released exosomes. Analyses of cytokine function revealed that while CCL3 in the exosomes was crucial to the phagocytic activity of RAW264.7 cells, TNF-α and IFN-γ primarily contributed to the enhancement of NO synthesis. These results suggest that treatment with LPS/IFN-γ alters the physicochemical properties of exosomes released from macrophages in order to facilitate association with ERAP1 and several cytokines/chemokines. This leads to exosome-mediated enhancement of macrophage functions. It is possible that packaging effector molecules into exosomes upon inflammatory stimuli, facilitates the exertion of effective pathophysiological functions on macrophages. Our data provide the first evidence that ERAP1 associated with exosomes plays important roles in inflammatory processes via activation of macrophages.


Assuntos
Aminopeptidases/metabolismo , Exossomos/metabolismo , Ativação de Macrófagos , Macrófagos/metabolismo , Antígenos de Histocompatibilidade Menor/metabolismo , Aminopeptidases/genética , Animais , Citocinas/genética , Citocinas/metabolismo , Exossomos/genética , Inflamação/genética , Inflamação/metabolismo , Camundongos , Camundongos Knockout , Antígenos de Histocompatibilidade Menor/genética , Fagocitose , Células RAW 264.7
11.
Bioorg Med Chem Lett ; 27(22): 5022-5026, 2017 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-29029932

RESUMO

Protein O-GlcNAcylation regulates various biological processes, and is associated with several diseases. Therefore, the development of quantitative proteomics is important for understanding the mechanisms of O-GlcNAc-related diseases. We previously reported selective enrichment of O-GlcNAcylated peptides, which provided high-selectivity and effective release by a novel thiol-alkyne and thiol-disulfide exchange. Here, we describe a new approach using initial isobaric tag labeling for relative quantification followed by enrichment and ß-elimination/Michael addition with dithiothreitol for identification of both proteins and modification sites. The approach was validated using model proteins and peptides. This novel strategy could be used for quantitative O-GlcNAcome of biological samples.


Assuntos
Acetilglucosamina/análise , Peptídeos/análise , Proteômica , Acetilglucosamina/metabolismo , Alcinos/química , Animais , Bovinos , Cromatografia Líquida de Alta Pressão , Cristalinas/química , Cristalinas/metabolismo , Dissulfetos/química , Glicosilação , Peptídeos/química , Peptídeos/metabolismo , Espectrometria de Massas em Tandem
12.
Biochim Biophys Acta Gen Subj ; 1861(10): 2462-2472, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28711406

RESUMO

BACKGROUND: O-mannosyl glycans have been found in a limited number of glycoproteins of the brain, nerves, and skeletal muscles, particularly in α-dystroglycan (α-DG). Defects in O-mannosyl glycan on α-DG are the primary cause of a group of congenital muscular dystrophies, which are collectively termed α-dystroglycanopathy. Recent studies have revealed various O-mannosyl glycan structures, which can be classified as core M1, core M2, and core M3 glycans. Although many dystroglycanopathy genes are involved in core M3 processing, the structure and biosynthesis of core M3 glycan remains only partially understood. SCOPE OF REVIEW: This review presents recent findings about the structure, biosynthesis, and pathology of O-mannosyl glycans. MAJOR CONCLUSIONS: Recent studies have revealed that the entire structure of core M3 glycan, including ribitol-5-phosphate, is a novel structure in mammals; its unique biosynthetic pathway has been elucidated by the identification of new causative genes for α-dystroglycanopathies and their functions. GENERAL SIGNIFICANCE: O-mannosyl glycan has a novel, unique structure that is important for the maintenance of brain and muscle functions. These findings have opened up a new field in glycoscience. These studies will further contribute to the understanding of the pathomechanism of α-dystroglycanopathy and the development of glycotherapeutics. This article is part of a Special Issue entitled Neuro-glycoscience, edited by Kenji Kadomatsu and Hiroshi Kitagawa.


Assuntos
Distroglicanas/química , Distrofias Musculares/metabolismo , N-Acetilglucosaminiltransferases/química , Pentosefosfatos/metabolismo , Processamento de Proteína Pós-Traducional , Síndrome de Walker-Warburg/metabolismo , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Sequência de Carboidratos , Distroglicanas/genética , Distroglicanas/metabolismo , Glicosilação , Humanos , Manose/química , Manose/metabolismo , Modelos Moleculares , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Distrofias Musculares/genética , Distrofias Musculares/patologia , N-Acetilglucosaminiltransferases/genética , N-Acetilglucosaminiltransferases/metabolismo , Pentosefosfatos/química , Polissacarídeos/química , Polissacarídeos/metabolismo , Síndrome de Walker-Warburg/genética , Síndrome de Walker-Warburg/patologia
13.
J Biochem ; 161(1): 99-111, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28053144

RESUMO

Alterations of the structure and/or amount of glycans present on proteins are associated with many diseases. We previously demonstrated that changes in N-glycans alter Aß production. In the present study, we focused on the relationship between Alzheimer's disease (AD) and O-glycan, another type of glycan. The UDP-N-acetylgalactosamine:polypeptide N-acetylgalactosaminyltransferase (GalNAc-T) family functions in the first step of mucin-type O-glycan synthesis. Analysis of the expression of GalNAc-Ts in the human brain using real-time PCR revealed that the expression of several GalNAc-Ts was altered with sporadic AD progression. Three of these GalNAc-Ts (GalNAc-T1, GalNAc-T4 and GalNAc-T6) were transfected into HEK293T cells to examine their impact on Aß production. Transfection of GalNAc-T6 significantly reduced both Aß1-40 and Aß1-42 generation, but GalNAc-T1 and GalNAc-T4 only reduced Aß1-40 generation. Although these three GalNAc-Ts exhibited enzymatic activities on soluble amyloid precursor protein (APP), the GalNAc transferase activity of GalNAc-T6 to APP was most prominent. The expression of α-secretase and ß-secretase was slightly altered in the transfected cells, but the activities of α-secretase and ß-secretase were not significantly altered. These data suggest that excess O-glycosylation on APP by GalNAc-T6 inhibits Aß production.


Assuntos
Precursor de Proteína beta-Amiloide/metabolismo , N-Acetilgalactosaminiltransferases/metabolismo , Agregação Patológica de Proteínas/metabolismo , Secretases da Proteína Precursora do Amiloide/biossíntese , Secretases da Proteína Precursora do Amiloide/genética , Precursor de Proteína beta-Amiloide/genética , Glicosilação , Células HEK293 , Humanos , N-Acetilgalactosaminiltransferases/genética , Agregação Patológica de Proteínas/genética
14.
Clin J Gastroenterol ; 10(2): 147-153, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28013449

RESUMO

Among the various manifestations of colonic involvement in malignant lymphomas, an ulcerative colitis-like appearance is rare. Herein, we describe a case in which extranodal colonic involvement resembled ulcerative colitis in a patient with advanced follicular lymphoma. A 59-year-old Japanese man with diarrhea and body weight loss was referred to our hospital. Computed tomography (CT) revealed systemic lymphadenopathy, splenomegaly, and thickening of the sigmoid colon and rectum walls. 18F-fluorodeoxy-glucose positron emission tomography (18F-FDG-PET/CT) revealed intense tubular 18F-FDG accumulation extending from the rectum to the colon at the hepatic flexure and much weaker accumulation in the systemic lymph nodes, bone marrow, and spleen. The isotope-enriched areas had an ulcerative colitis-like appearance as shown via colonoscopy. The patient was ultimately diagnosed with follicular lymphoma (stage IV A, grade 1) based on a pathological examination of the neck lymph nodes, iliac bone marrow, and colon. After six courses of chemotherapy (R-CHOP), 18F-FDG-PET/CT confirmed complete remission of the lymphoma including the colonic lesion. This is presumably the first case of ulcerative-like colitis caused by a follicular lymphoma. As a novel approach, the lymphoma-related colitis was detected by comparing the pathology results and the 18F-FDG-PET/CT results.


Assuntos
Colite Ulcerativa/etiologia , Linfoma Folicular/complicações , Anticorpos Monoclonais Murinos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Biópsia , Colite Ulcerativa/diagnóstico por imagem , Colite Ulcerativa/patologia , Colonoscopia/métodos , Ciclofosfamida/uso terapêutico , Doxorrubicina/uso terapêutico , Humanos , Intestino Grosso/patologia , Linfoma Folicular/tratamento farmacológico , Linfoma Folicular/patologia , Masculino , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Prednisona/uso terapêutico , Rituximab , Tomografia Computadorizada por Raios X/métodos , Vincristina/uso terapêutico
15.
Biol Reprod ; 94(1): 21, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26632610

RESUMO

Producing many mature oocytes is of great importance for assisted reproductive technologies. In mice, superovulation by consecutive injections of equine chorionic gonadotropin (eCG) and human chorionic gonadotropin (hCG) has been the gold standard for oocyte collection. However, the yield of mature oocytes by this regimen can fluctuate according to the stage of the estrous cycle, strain, and age. Therefore, our objective was to develop a high-yield superovulation protocol to collect higher numbers of oocytes from adult female mice of different strains and ages. First, we aimed to synchronize the estrous cycle using C57BL/6 (B6) female mice. Most (93%) were synchronized to metestrus after two daily injections of progesterone. Second, we found that with the injection of anti-inhibin serum (AIS) instead of eCG, the mean number of ovulated oocytes almost doubled (21 vs. 41 per mouse). Third, by combining estrous cycle synchronization with two AIS injections, we obtained 62 oocytes per mouse, about three times that with the eCG-hCG protocol. Importantly, this approach increased the proportion of mice that ovulated >25 oocytes from about 40% (eCG-hCG) to 90%. The same protocol was also effective in other inbred (BALB/cA), outbred (ICR), and hybrid (B6D2F1) strains. In addition, B6 female mice aged over 1 yr ovulated 1.8-fold more oocytes by this protocol. Thus, estrous cycle synchronization followed by AIS-hCG yielded a broadly applicable, highly efficient superovulation. This protocol should promote the effective use of invaluable female mouse strains and decrease the numbers of animals euthanized.


Assuntos
Anticorpos Bloqueadores/farmacologia , Sincronização do Estro/efeitos dos fármacos , Inibinas/antagonistas & inibidores , Inibinas/imunologia , Superovulação/efeitos dos fármacos , Envelhecimento , Animais , Gonadotropina Coriônica/farmacologia , Feminino , Fertilização in vitro/métodos , Hormônio Foliculoestimulante/sangue , Metestro/fisiologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos ICR , Oócitos , Gravidez , Progesterona/farmacologia , Zona Pelúcida/efeitos dos fármacos
16.
Biol Pharm Bull ; 38(9): 1389-94, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26328495

RESUMO

Protein O-linked mannose ß1,2-N-acetylglucosaminyltransferase 1 (POMGNT1) is a Golgi glycosyltransferase that catalyzes the formation of the N-acetylglucosamine (GlcNAc) ß1→2Man linkage of O-mannosyl glycan. POMGNT1 is not modified by N-glycans because there are no potential N-glycosylation sites; however, it is not clear whether POMGNT1 is modified by O-glycans. To determine whether POMGNT1 is O-glycosylated, we prepared recombinant human POMGNT1 from HEK293T cells. The recombinant POMGNT1 was recognized by Sambucus sieboldiana lectin (SSA), and sialidase digestion of POMGNT1 decreased SSA reactivity and enhanced the reactivity of Arachis hypogaea lectin (PNA). These results suggest that POMGNT1 is modified by a sialylated core-1 O-glycan. Next, we analyzed the structures of the O-glycans on POMGNT1 by ß-elimination and pyrazolone-labeling methods in combination with mass spectrometry. We identified several mucin-type O-glycans containing (NeuAc)1(Hex)1(HexNAc)1, (NeuAc)2(Hex)1(HexNAc)1, and (NeuAc)2(Hex)2(HexNAc)2. To examine whether the O-glycans affect the functions and properties of POMGNT1, we compared glycosylated and non-glycosylated forms of recombinant sPOMGNT1 for their activity and surface hydrophobicity using the hydrophobic probe 1-anilino-8-naphthalene sulfonate (ANS). POMGNT1 activity and surface hydrophobicity were not affected by the presence or absence of O-glycans.


Assuntos
N-Acetilglucosaminiltransferases/metabolismo , Polissacarídeos/metabolismo , Glicosilação , Células HEK293 , Humanos , Lectinas de Plantas/metabolismo , Proteínas Recombinantes/metabolismo , Proteínas Inativadoras de Ribossomos/metabolismo
17.
Geriatr Gerontol Int ; 15(6): 673-87, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25656311

RESUMO

BACKGROUND: The demographic structure of a country changes dramatically with increasing trends toward general population aging and declining birth rates. In Japan, the percentage of the elderly population (aged ≥65 years) reached 25% in 2013; it is expected to exceed 30% in 2025 and reach 39.9% in 2060. The national total population has been decreasing steadily since its peak reached in 2008, and it is expected to fall to the order of 80 million in 2060. Of the total population, those aged ≥75 years accounted for 12.3% as of 2013, and this is expected to reach 26.9% in 2060. As the demographic structure changes, the disease structure changes, and therefore the medical care demand changes. To accommodate the medical care demand changes, it is necessary to secure a system for providing medical care. Japan has thus far attained remarkable achievements in medical care, seeking a better prognosis for survival; however, its medical care demand is anticipated to change both qualitatively and quantitatively. As diseases in the elderly, particularly in the old-old population, are often intractable, conventional medical care must be upgraded to one suitable for an aged society. What is required to this end is a shift from "cure-seeking medical care" focusing on disease treatment on an organ-specific basis to "cure and support-seeking medical care" with treatments reprioritized to maximize the quality of life (QOL) for the patient, or a change from "hospital-centered medical care" to "community-oriented medical care" in correlation with nursing care and welfare. CURRENT SITUATION AND PROBLEMS: (1) Necessity for a paradigm shift to "cure-and-support seeking medical care" In addition to the process of aging with functional deterioration of multiple organs, the elderly often suffer from systemically disordering diseases, such as lifestyle-related diseases, as well as geriatric syndrome and daily activity dysfunction; therefore, integrated and comprehensive medical care is required. In addition, with regard to diseases in the elderly, not only their acute stage, but also their chronic and intermediate stages must be emphasized in their treatment. Aiming to achieve a complete cure of disease by exploring the cause and implementing radical treatment, the conventional medical care model is difficult to apply to the medical care of the elderly; medical care suitable for the elderly is required. (2) Spread of home-based care and the necessity for human resources development Many elderly people want to continue to live in their house and their community where they have been living for a long time, even with disease. There are increasing needs for QOL-emphasizing home-based care for patients in the intermediate stage after completion of acute stage treatment, or for end-of-life care. Hence, there is a demand for a shift to "community-oriented medical care" for providing comprehensive care supported with medical and nursing resources available in the community. As the percentage of the elderly population (aged ≥65 years) and the availability of medical care resources vary considerably among different regions, it is important that specialists in the fields of public health, medical care, nursing care, and welfare work on establishing a collaborative system suitable for the local characteristics of each region by making the best use of their own specialties. (3) Necessity for establishing a department of gerontology or geriatric medicine at each medical school In line with the increasing number of elderly people, it is necessary to upgrade the systems for educating and nurturing physicians engaged in healthcare and nursing care for the elderly. It is also necessary to develop the organic cooperation with other medical and nursing care professionals, such as registered nurses and care workers. At present, just approximately 30% of medical schools in Japan have a department specializing in medical care for the elderly and relevant medical education; there is an urgent need to improve the situation, as the majority of universities do not provide any such education. (4) Necessity for establishing a medical center for promoting medical care provider collaboration, multidisciplinary training and a means to increase public awareness In the medical care for the elderly, comprehensive care must be provided from the viewpoints of both healthcare and nursing care; to improve the quality of such care services, multidisciplinary collaboration and team-based medicine are indispensable. Therefore, physicians, nurses, therapists, pharmacists, dieticians, care managers, and other health care professionals who have thorough knowledge about medical care for the elderly are of utmost necessity. In reality, however, the collaboration of these health care professionals is unsatisfactory, and the degree of understanding of team-based medicine by each medical professional is low. Therefore, as in the case of the establishment of cancer centers within individual regions to promote medical care for cancer, there is a demand to nurture professionals engaged in medical care for the elderly, and to establish a core facility for the promotion of multidisciplinary collaboration and team-based medicine for each region. (5) Do the people understand the paradigm shift? Currently, not only healthcare professionals, but also many citizens seek "cure-seeking medical care" aiming at a restoration of organ function; however, surveys of the elderly often show that they want to restore independent daily activity, rather than to achieve a "cure." In contrast, in the actual medical care setting, contradictory situations prevail in which the public awareness of the shift to "cure-and-support seeking medical care" is unsatisfactory, including the fact that the majority of recipients of tertiary emergency care are elderly patients. CONTENTS OF THE PROPOSAL: The Science Council of Japan has the task to propose future visions for the Japanese aging society not only from the viewpoint of the health of each individual, but also from a broader perspective, taking into account the relationship between humans and society. Various issues related to general population aging are posing serious problems, which require prompt resolution. Although we made a number of proposals at the 21st Subcommittee for Aging, the situation has not changed satisfactorily. Accordingly, the present proposals on specific solutions were designed. (1) In a super-aged society, a paradigm shift to "cure-and-support seeking medical care" should be implemented A super-aged society will consist of an unprecedented demographic structure in which the percentage of only those people aged ≥75 years will increase in the entire population. Therefore, there is an urgent need to prepare for increasing populations of persons in need of long-term care and those who are likely to become in need of long-term care. Given the consideration that "patients are not merely sick persons, but rather living persons," a paradigm shift from conventional "cure-seeking medical care" to "cure and support-seeking medical care" must be implemented. (2) Facilitate a paradigm shift to community-oriented medical care, and promote the activity of female physicians in the medical care for the elderly A paradigm shift should be promptly facilitated by reorganizing hospital functions and establishing a community comprehensive care system for home-based care to promote the participation of the elderly by themselves in care-supporting society. To further promote the collaboration of medical care and welfare, not only persons in charge of actual regional settings, but also university schools of medicine and regional core medical institutions experienced in medical care for the elderly should take the initiative to promote home-based care and facilitate a paradigm shift to community-oriented medical care. In addition, programs should also be developed to re-educate female physicians who became housewives in order to nurture them to become facilitators of geriatric medicine. (3) Physicians who are required at local medical facilities must be nurtured through the establishment of a department of gerontology or geriatric medicine at each medical school To facilitate efficient medical care services, medical education and research, and human resources development in support of expected paradigm shifts, it is considered that a department of gerontology or geriatric medicine should be established at each medical school. Furthermore, it is necessary to allocate dedicated teachers of medical care for the elderly to all medical schools, as well as to upgrade practice-participatory drills and to collaborate with a broad range of entities, including local medical institutions, and welfare and nursing care facilities. Efforts must be made to nurture locally wanted physicians through specific efforts concerning team-based medicine. (4) Promote the establishment of centers for geriatrics and gerontology (provisional name) for medical care collaboration, multidisciplinary training, and a means to increase public awareness To promote the uniform accessibility of expertise on efficient medical care that is best suited for a super-aged society, it is necessary to build a post-graduation educational system under the initiatives of the Japan Geriatrics Society and the National Center for Geriatrics and Gerontology across the nation in cooperation with regional medical schools and the Japan Medical Association. Furthermore, at least one hospital serving as a center for geriatrics and gerontology should be established in each regional block (Hokkaido, Tohoku, Koshinetsu, Hokuriku/Tokai, Kinki, Chushikoku and Kyushu/Okinawa) by making the best use of existing hospitals. Byestablishing these centers, uniform accessibility for the quality of medical care for the elderly in each region is expected. (ABSTRACT TRUNCATED).


Assuntos
Atenção à Saúde/tendências , Dinâmica Populacional , Atividades Cotidianas , Idoso de 80 Anos ou mais , Geriatria/normas , Geriatria/tendências , Produto Interno Bruto , Necessidades e Demandas de Serviços de Saúde/tendências , Humanos , Japão , Expectativa de Vida/tendências , Dinâmica Populacional/tendências , Qualidade de Vida
18.
Glycobiology ; 24(3): 314-24, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24352591

RESUMO

The human natural killer-1 (HNK-1) carbohydrate comprising a sulfated trisaccharide (HSO3-3GlcAß1-3Galß1-4GlcNAc-) is expressed on N-linked and O-mannose-linked glycans in the nervous system and involved in learning and memory functions. Although whole/core glycan structures and carrier glycoproteins for the N-linked HNK-1 epitope have been studied, carrier glycoproteins and the biosynthetic pathway of the O-mannose-linked HNK-1 epitope have not been fully characterized. Here, using mass spectrometric analyses, we identified the major carrier glycoprotein of the O-linked HNK-1 as phosphacan in developing mouse brains and determined the major O-glycan structures having the terminal HNK-1 epitope from partially purified phosphacan. The O-linked HNK-1 epitope on phosphacan almost disappeared due to the knockout of protein O-mannose ß1,2-N-acetylglucosaminyltransferase 1, an N-acetylglucosaminyltransferase essential for O-mannose-linked glycan synthesis, indicating that the reducing terminal of the O-linked HNK-1 is mannose. We also showed that glucuronyltransferase-P (GlcAT-P) was involved in the biosynthesis of O-mannose-linked HNK-1 using the gene-deficient mice of GlcAT-P, one of the glucuronyltransferases for HNK-1 synthesis. Consistent with this result, we revealed that GlcAT-P specifically synthesized O-linked HNK-1 onto phosphacan using cultured cells. Furthermore, we characterized the as-yet-unknown epitope of the 6B4 monoclonal antibody (mAb), which was thought to recognize a unique phosphacan glycoform. The reactivity of the 6B4 mAb almost completely disappeared in GlcAT-P-deficient mice, and exogenously expressed phosphacan was selectively recognized by the 6B4 mAb when co-expressed with GlcAT-P, suggesting that the 6B4 mAb preferentially recognizes O-mannose-linked HNK-1 on phosphacan. This is the first study to show that 6B4 mAb-reactive O-mannose-linked HNK-1 in the brain is mainly carried by phosphacan.


Assuntos
Encéfalo/metabolismo , Antígenos CD57/metabolismo , Manose/metabolismo , Processamento de Proteína Pós-Traducional , Proteínas Tirosina Fosfatases Classe 5 Semelhantes a Receptores/metabolismo , Animais , Encéfalo/crescimento & desenvolvimento , Antígenos CD57/química , Células COS , Configuração de Carboidratos , Chlorocebus aethiops , Glucuronosiltransferase/metabolismo , Glicosilação , Células HEK293 , Humanos , Manose/química , Camundongos , Camundongos Endogâmicos C57BL , N-Acetilglucosaminiltransferases/metabolismo , Proteínas Tirosina Fosfatases Classe 5 Semelhantes a Receptores/química
19.
Jpn J Radiol ; 32(2): 69-79, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24337887

RESUMO

PURPOSE: To investigate the hemodynamics and progression of a hypervascular focus (HF) in a borderline lesion by dual-phase CT during hepatic arteriography (CTHA) and reveal the process of the transformation to hypervascular overt hepatocellular carcinoma (HCC). MATERIALS AND METHODS: This study was performed with the approval of our institutional ethics committee, and informed consent for the retrospective usage of clinical materials was obtained from all the patients. The 121 nodules in 76 consecutive patients with liver cirrhosis and chronic hepatitis showing an HF in a borderline lesion on angiography-assisted CT were analyzed. Hemodynamic changes were observed in 24 patients who underwent repeated angiography-assisted CT. Histopathological analysis was conducted in eight nodules. RESULTS: HF was classifiable into type A (stain disappeared), B (stain prolonged), C (stain was washed out and corona-like drainage into the outer nodule was seen) and D (stain was washed out and corona-like drainage into the whole outer nodule was seen) on the late phase of CTHA and was seen to progress in this order on follow-up observation. Histopathologically, de-differentiated foci showed significantly higher expression of sinusoidal capillarization and unpaired arteries than background nodules and showed pseudocapsule, compressive and replacing growth at the border of the background nodule. CONCLUSION: HF showed multi-step progression and transformation to hypervascular overt HCC.


Assuntos
Angiografia , Carcinoma Hepatocelular/fisiopatologia , Neoplasias Hepáticas/fisiopatologia , Tomografia Computadorizada por Raios X , Idoso , Idoso de 80 Anos ou mais , Carcinoma Hepatocelular/diagnóstico por imagem , Carcinoma Hepatocelular/patologia , Progressão da Doença , Feminino , Hemodinâmica , Humanos , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/patologia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
20.
Biochem Biophys Res Commun ; 440(1): 88-93, 2013 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-24041696

RESUMO

Hypoglycosylation is a common characteristic of dystroglycanopathy, which is a group of congenital muscular dystrophies. More than ten genes have been implicated in α-dystroglycanopathies that are associated with the defect in the O-mannosylation pathway. One such gene is GTDC2, which was recently reported to encode O-mannose ß-1,4-N-acetylglucosaminyltransferase. Here we show that GTDC2 generates CTD110.6 antibody-reactive N-acetylglucosamine (GlcNAc) epitopes on the O-mannosylated α-dystroglycan (α-DG). Using the antibody, we show that mutations of GTDC2 identified in Walker-Warburg syndrome and alanine-substitution of conserved residues between GTDC2 and EGF domain O-GlcNAc transferase resulted in decreased glycosylation. Moreover, GTDC2-modified GlcNAc epitopes are localized in the endoplasmic reticulum (ER). These data suggested that GTDC2 is a novel glycosyltransferase catalyzing GlcNAcylation of O-mannosylated α-DG in the ER. CTD110.6 antibody may be useful to detect a specific form of GlcNAcylated O-mannose and to analyze defective O-glycosylation in α-dystroglycanopathies.


Assuntos
Acetilglucosamina/metabolismo , Distroglicanas/metabolismo , Retículo Endoplasmático/metabolismo , Epitopos/metabolismo , Glicosiltransferases/metabolismo , Acetilglucosamina/imunologia , Animais , Anticorpos/imunologia , Distroglicanas/química , Distroglicanas/imunologia , Retículo Endoplasmático/imunologia , Epitopos/imunologia , Glicosilação , Glicosiltransferases/genética , Glicosiltransferases/imunologia , Células HEK293 , Humanos , Mutação , Estrutura Terciária de Proteína , Síndrome de Walker-Warburg/genética , Síndrome de Walker-Warburg/imunologia , Síndrome de Walker-Warburg/metabolismo
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