RESUMO
Aim Investigate whether inheritance of improved skeletal muscle mitochondrial function and its association with glycemic control are multigenerational benefits of exercise. MAIN METHODS: Male Swiss mice were subjected to 8 weeks of endurance training and mated with untrained females. KEY FINDINGS: Trained fathers displayed typical endurance training-induced adaptations. Remarkably, offspring from trained fathers also exhibited higher endurance performance, mitochondrial oxygen consumption, glucose tolerance and insulin sensitivity. However, PGC-1α expression was not increased in the offspring. In the offspring, the expression of the co-repressor NCoR1 was reduced, increasing activation of PGC-1α target genes. These effects correlated with higher DNA methylation at the NCoR1 promoter in both, the sperm of trained fathers and in the skeletal muscle of their offspring. SIGNIFICANCE: Higher skeletal muscle mitochondrial function is inherited by epigenetic de-activation of a key PGC-1α co-repressor.
Assuntos
Mitocôndrias/metabolismo , Condicionamento Físico Animal/fisiologia , Esforço Físico/fisiologia , Animais , Metilação de DNA , Epigênese Genética/genética , Feminino , Masculino , Camundongos , Mitocôndrias/fisiologia , Músculo Esquelético/fisiologia , Correpressor 1 de Receptor Nuclear/metabolismo , Consumo de Oxigênio/fisiologia , Herança Paterna/fisiologia , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Receptores Ativados por Proliferador de Peroxissomo/metabolismo , Receptores Ativados por Proliferador de Peroxissomo/fisiologia , Condicionamento Físico Animal/métodos , RNA Mensageiro/genéticaRESUMO
Type 2 diabetes mellitus (T2DM) is characterized by the inability of the insulin-producing ß-cells to overcome insulin resistance. We previously identified an imprinted region on chromosome 14, the DLK1-MEG3 locus, as being downregulated in islets from humans with T2DM. In this study, using targeted epigenetic modifiers, we prove that increased methylation at the promoter of Meg3 in mouse ßTC6 ß-cells results in decreased transcription of the maternal transcripts associated with this locus. As a result, the sensitivity of ß-cells to cytokine-mediated oxidative stress was increased. Additionally, we demonstrate that an evolutionarily conserved intronic region at the MEG3 locus can function as an enhancer in ßTC6 ß-cells. Using circular chromosome conformation capture followed by high-throughput sequencing, we demonstrate that the promoter of MEG3 physically interacts with this novel enhancer and other putative regulatory elements in this imprinted region in human islets. Remarkably, this enhancer is bound in an allele-specific manner by the transcription factors FOXA2, PDX1, and NKX2.2. Overall, these data suggest that the intronic MEG3 enhancer plays an important role in the regulation of allele-specific expression at the imprinted DLK1-MEG3 locus in human ß-cells, which in turn impacts the sensitivity of ß-cells to cytokine-mediated oxidative stress.
Assuntos
Metilação de DNA , Diabetes Mellitus Tipo 2/metabolismo , Regulação da Expressão Gênica , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Ilhotas Pancreáticas/metabolismo , Proteínas de Membrana/metabolismo , Regiões Promotoras Genéticas , RNA Longo não Codificante/metabolismo , Animais , Proteínas de Ligação ao Cálcio , Linhagem Celular , Citocinas/metabolismo , DNA (Citosina-5-)-Metiltransferase 1/química , DNA (Citosina-5-)-Metiltransferase 1/genética , DNA (Citosina-5-)-Metiltransferase 1/metabolismo , Diabetes Mellitus Tipo 2/patologia , Elementos Facilitadores Genéticos , Epigênese Genética , Loci Gênicos , Proteínas de Fluorescência Verde/química , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Proteína Homeobox Nkx-2.2 , Proteínas de Homeodomínio/química , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/genética , Ilhotas Pancreáticas/patologia , Região de Controle de Locus Gênico , Proteínas de Membrana/genética , Camundongos , Mutação , Proteínas Nucleares , Estresse Oxidativo/efeitos dos fármacos , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Repressoras/química , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Bancos de Tecidos , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
BACKGROUND: Genome-wide association studies have established ADAMTS7 as a locus for coronary artery disease in humans. However, these studies fail to provide directionality for the association between ADAMTS7 and coronary artery disease. Previous reports have implicated ADAMTS7 in the regulation of vascular smooth muscle cell migration, but a role for and the direction of impact of this gene in atherogenesis have not been shown in relevant model systems. METHODS AND RESULTS: We bred an Adamts7 whole-body knockout mouse onto both the Ldlr and Apoe knockout hyperlipidemic mouse models. Adamts7(-/-)/Ldlr(-/-) and Adamts7(-/-)/Apoe(-/-) mice displayed significant reductions in lesion formation in aortas and aortic roots compared with controls. Adamts7 knockout mice also showed reduced neointimal formation after femoral wire injury. Adamts7 expression was induced in response to injury and hyperlipidemia but was absent at later time points, and primary Adamts7 knockout vascular smooth muscle cells showed reduced migration in the setting of tumor necrosis factor-α stimulation. ADAMTS7 localized to cells positive for smooth muscle cell markers in human coronary artery disease lesions, and subcellular localization studies in cultured vascular smooth muscle cells placed ADAMTS7 at the cytoplasm and cell membrane, where it colocalized with markers of podosomes. CONCLUSIONS: These data represent the first in vivo experimental validation of the association of Adamts7 with atherogenesis, likely through modulation of vascular cell migration and matrix in atherosclerotic lesions. These results demonstrate that Adamts7 is proatherogenic, lending directionality to the original genetic association and supporting the concept that pharmacological inhibition of ADAMTS7 should be atheroprotective in humans, making it an attractive target for novel therapeutic interventions.