RESUMO
BACKGROUND: Causative mutations cannot be identified in the majority of Asian patients with suspected maturity-onset diabetes of the young (MODY). OBJECTIVES: To elucidate the genetic basis of Japanese patients with MODY-like diabetes and gain insight into the etiology of patients without mutations in the major MODY genes. SUBJECTS: A total of 263 Japanese patients with early-onset, non-obese, MODY-like diabetes mellitus referred to Osaka City General Hospital for diagnosis. METHODS: Mutational analysis of the four major MODY genes (GCK, HNF1A, HNF4A, HNF1B) by Sanger sequencing. Mutation-positive and mutation-negative patients were further analyzed for clinical features. RESULTS: Mutations were identified in 103 (39.2%) patients; 57 mutations in GCK; 29, HNF1A; 7, HNF4A; and 10, HNF1B. Contrary to conventional diagnostic criteria, 18.4% of mutation-positive patients did not have affected parents and 8.2% were in the overweight range (body mass index [BMI] >85th percentile). HOMA-IR at diagnosis was elevated (>2) in 15 of 66 (22.7%) mutation-positive patients. Compared with mutation-positive patients, mutation-negative patients were significantly older (P = 0.003), and had higher BMI percentile at diagnosis (P = 0.0006). Interestingly, maternal inheritance of diabetes was significantly more common in mutation-negative patients (P = 0.0332) and these patients had significantly higher BMI percentile as compared with mutation-negative patients with paternal inheritance (P = 0.0106). CONCLUSIONS: Contrary to the conventional diagnostic criteria, de novo diabetes, overweight, and insulin-resistance are common in Japanese patients with mutation-positive MODY. A significant fraction of mutation-negative patients had features of early-onset type 2 diabetes common in Japanese, and non-Mendelian inheritance needs to be considered for these patients.
Assuntos
Diabetes Mellitus Tipo 2/genética , Fatores Nucleares de Hepatócito/genética , Herança Materna , Proteínas Serina-Treonina Quinases/genética , Adolescente , Adulto , Criança , Pré-Escolar , Diabetes Mellitus Tipo 2/epidemiologia , Feminino , Quinases do Centro Germinativo , Humanos , Japão/epidemiologia , Masculino , Adulto JovemRESUMO
BNIP-2 shows high homology with the Cayman ataxia protein, caytaxin, which functions as a kinesin-1 adapter bridging cargos and kinesin light chains (KLCs). BNIP-2 is known to induce cell shape changes when over-expressed in culture cells, but its physiological functions are mostly unknown. BNIP-2 interacts with KLC through the conserved WED motif in the N-terminal region of BNIP-2. Interaction with KLC and transportation by kinesin-1 are essential for over-expressed BNIP-2 to elongate cells and induce cellular processes. Endogenous BNIP-2 localizes to the Golgi apparatus, early and recycling endosomes and mitochondria, aligned with microtubules, and moves at a speed compatible with kinesin-1 transportation. The CRAL-TRIO domain of BNIP-2 specifically interacts with phosphatidylserine, and the vesicular localization of BNIP-2 requires interaction with this phospholipid. BNIP-2 mutants which do not bind phosphatidylserine do not induce morphological changes in cells. These data show that similar to caytaxin, BNIP-2 is a kinesin-1 adapter involved in vesicular transportation in the cytoplasm and that association with cargos depends on interaction of the CRAL-TRIO domain with membrane phosphatidylserine.
Assuntos
Proteínas de Transporte/metabolismo , Endossomos/metabolismo , Complexo de Golgi/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Fosfatidilserinas/metabolismo , Animais , Células COS , Membrana Celular/metabolismo , Chlorocebus aethiops , Células HEK293 , Células HeLa , Humanos , Cinesinas , Ligação ProteicaAssuntos
Mesilato de Imatinib/uso terapêutico , Proteínas de Fusão Oncogênica/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Receptor beta de Fator de Crescimento Derivado de Plaquetas/genética , Transativadores/genética , Adulto , Medula Óssea/metabolismo , Medula Óssea/patologia , Terapia Combinada , Transplante de Células-Tronco de Sangue do Cordão Umbilical , Humanos , Masculino , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/terapia , Resultado do Tratamento , Adulto JovemRESUMO
The activation of T cells is known to be accompanied by the temporary downmodulation of the TCR/CD3 complex on the cell surface. Here, we established a novel monoclonal antibody, Dow2, that temporarily induces downmodulation of the TCR/CD3 complex in mouse CD4(+) T cells without activating T cells. Dow2 recognized the determinant on CD3ε; however, differences were observed in the binding mode between Dow2 and the agonistic anti-CD3ε Ab, 145-2C11. An injection of Dow2 in vivo resulted in T-cell anergy, and prolonged the survival of cardiac allografts without a marked increase in cytokine release. The phosphorylated forms of the signaling proteins PLC-γ1 and LAT in Dow2-induced anergic T cells were markedly decreased upon stimulation. However, the levels of phosphorylated LAT and PLCγ1 in Dow2-induced anergic T cells could be rescued in the presence of the proteasome inhibitor MG-132. These results suggest that proteasome-mediated degradation is involved in hypophosphorylated LAT and PLCγ1 in Dow2-induced anergic T cells. The novel CD3-specific Ab, Dow2, may provide us with a unique tool for inducing immunosuppression.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/imunologia , Anticorpos Monoclonais Murinos/farmacologia , Complexo CD3/imunologia , Anergia Clonal/efeitos dos fármacos , Proteínas de Membrana/imunologia , Fosfolipase C gama/imunologia , Fosfoproteínas/imunologia , Linfócitos T/imunologia , Animais , Anticorpos Monoclonais Murinos/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Fosforilação/efeitos dos fármacos , Fosforilação/imunologia , Complexo de Endopeptidases do Proteassoma/imunologia , Proteólise/efeitos dos fármacosRESUMO
AIMS/INTRODUCTION: To investigate the genetic background of Japanese patients with suspected maturity-onset diabetes of the young (MODY). MATERIALS AND METHODS: On 340 proband patients referred from across Japan, genomic variants were analyzed using a targeted multigene panel analysis combined with the multiplex ligation probe amplification (MLPA) analysis, mitochondrial m.3243A > G analysis and methylation-specific polymerase chain reaction of the imprinted 6q24 locus. Pathogenic/likely pathogenic variants were listed according to the 2015 American College of Medical Genetics and Genomics and the Association for Molecular Pathology criteria. Additionally, variants with a population frequency <0.001 and Combined Annotation Dependent Depletion score >20 (CS >20) were listed as rare variants of uncertain significance-CS >20. RESULTS: A total of 157 pathogenic/likely pathogenic variants and 44 rare variants of uncertain significance-CS >20 were identified. In the pathogenic/likely pathogenic variants, alterations in the GCK gene were the most common (82, 52.2%) followed by HNF1A (29, 18.5%), HNF4A (13, 8.3%) and HNF1B (13, 8.3%). One patient was a 29.5% mosaic with a truncating INSR variant. In the rare variants of uncertain significance-CS >20, 20 (45.5%) were in the genes coding for the adenosine triphosphate-sensitive potassium channel, KCNJ11 or ABCC8, and four were in the genes of the insulin-signaling pathway, INSR and PIK3R1. Four variants in ABCC8 were previously reported in patients with congenital hyperinsulinism, suggesting the inactivating nature of these variants, and at least two of our patients had a history of congenital hyperinsulinism evolving into diabetes. In two patients with INSR or PIK3R1 variants, insulin resistance was evident at diagnosis. CONCLUSIONS: Causative genomic variants could be identified in at least 46.2% of clinically suspected MODY patients. ABCC8-MODY with inactivating variants could represent a distinct category of MODY. Genes of insulin resistance should be included in the sequencing panel for MODY.
Assuntos
Hiperinsulinismo Congênito , Diabetes Mellitus Tipo 2 , Resistência à Insulina , Humanos , Insulina/genética , Resistência à Insulina/genética , População do Leste Asiático , Diabetes Mellitus Tipo 2/epidemiologia , Mutação , Receptores de Sulfonilureias/genéticaRESUMO
Deficiency of caytaxin results in hereditary ataxia or dystonia in humans, mice and rats. Our yeast two-hybrid screen identified kinesin light chains (KLCs) as caytaxin-binding proteins. The tetratricopeptide-repeat region of KLC1 recognizes the ELEWED sequence (amino acids 115-120) of caytaxin. This motif is conserved among BNIP-2 family members and other KLC-interacting kinesin cargo proteins such as calsyntenins. Caytaxin associates with kinesin heavy chains (KHCs) indirectly by binding to KLCs, suggesting that caytaxin binds to the tetrameric kinesin molecule. In cultured hippocampal neurons, we found that caytaxin is distributed in both axons and dendrites in punctate patterns, and it colocalizes with microtubules and KHC. GFP-caytaxin expressed in hippocampal neurons is transported at a speed ( approximately 1 mum/second) compatible with kinesin movement. Inhibition of kinesin-1 by dominant-negative KHC decreases the accumulation of caytaxin in the growth cone. Caytaxin puncta do not coincide with vesicles containing known kinesin cargos such as APP or JIP-1. A part of caytaxin, however, colocalizes with mitochondria and suppression of caytaxin expression by RNAi redistributes mitochondria away from the distal ends of neurites. These data indicate that caytaxin binds to kinesin-1 and functions as an adaptor that mediates intracellular transport of specific cargos, one of which is the mitochondrion.
Assuntos
Transporte Axonal/fisiologia , Cinesinas/fisiologia , Proteínas do Tecido Nervoso/fisiologia , Neurônios/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/fisiologia , Motivos de Aminoácidos , Precursor de Proteína beta-Amiloide/fisiologia , Animais , Ataxia , Sítios de Ligação , Linhagem Celular , Hipocampo , Humanos , Cinesinas/química , Camundongos , Proteínas Associadas aos Microtúbulos/química , Proteínas Associadas aos Microtúbulos/fisiologia , Microtúbulos/fisiologia , Mitocôndrias/fisiologia , Proteínas do Tecido Nervoso/química , Neurônios/ultraestrutura , Nexinas de Proteases , Subunidades Proteicas/química , Subunidades Proteicas/fisiologia , Interferência de RNA , Ratos , Receptores de Superfície Celular/fisiologia , Técnicas do Sistema de Duplo-HíbridoRESUMO
BEN domain-containing protein 3 (BEND3) has no transmembrane region, is localized in the cytoplasm, and is involved in chromatin function and transcription. We here identified a novel subpopulation of human T cells that expressed BEND3 on their cell surface (BEND3(+) T cells). BEND3(+) T cells consisted of approximately 3% of T cells in the peripheral blood, were present in both CD4(+) and CD8(+) T cells, and were also observed in cord blood. The stimulation of BEND3(+) T cells through the TCR/CD3 complex led to the production of various kinds of cytokines; however, the levels of IL-6 and IL-8 produced by BEND3(+) T cells were higher than those by BEND3(-) T cells. The proportion of BEND3(+) T cells was also increased in some patients with inflammatory diseases. Taken together, these results indicate that BEND3(+) T cells are a new subpopulation of T cells in terms of their cytokine profile. Further analyses on BEND3(+) T cells may be of importance and useful in understanding human T cell immunology.