RESUMO
BACKGROUND/AIMS: Epigenetic regulation is considered the main molecular mechanism underlying the developmental origin of health and disease's (DOHAD) hypothesis. Previous studies that have investigated the role of paternal exercise on the metabolic health of the offspring did not control for the amount and intensity of the training or possible effects of adaptation to exercise and produced conflicting results regarding the benefits of parental exercise to the next generation. We employed a precisely regulated exercise regimen to study the transgenerational inheritance of improved metabolic health. METHODS: We subjected male mice to a well-controlled exercise -training program to investigate the effects of paternal exercise on glucose tolerance and insulin sensitivity in their adult progeny. To investigate the molecular mechanisms of epigenetic inheritance, we determined chromatin markers in the skeletal muscle of the offspring and the paternal sperm. RESULTS: Offspring of trained male mice exhibited improved glucose homeostasis and insulin sensitivity. Paternal exercise modulated the DNA methylation profile of PI3Kca and the imprinted H19/Igf2 locus at specific differentially methylated regions (DMRs) in the skeletal muscle of the offspring, which affected their gene expression. Remarkably, a similar DNA methylation profile at the PI3Kca, H19, and Igf2 genes was present in the progenitor sperm indicating that exercise-induced epigenetic changes that occurred during germ cell development contributed to transgenerational transmission. CONCLUSION: Paternal exercise might be considered as a strategy that could promote metabolic health in the offspring as the benefits can be inherited transgenerationally.
Assuntos
Classe I de Fosfatidilinositol 3-Quinases/genética , Metilação de DNA , Resistência à Insulina/genética , Fator de Crescimento Insulin-Like II/genética , Condicionamento Físico Animal/métodos , RNA Longo não Codificante/genética , Espermatozoides/química , Animais , Epigênese Genética , Feminino , Teste de Tolerância a Glucose , Sequenciamento de Nucleotídeos em Larga Escala , Masculino , Camundongos , Modelos Animais , Consumo de Oxigênio , Herança Paterna , Análise de Sequência de DNA , Espermatozoides/metabolismoRESUMO
Human pancreatic islets consist of multiple endocrine cell types. To facilitate the detection of rare cellular states and uncover population heterogeneity, we performed single-cell RNA sequencing (RNA-seq) on islets from multiple deceased organ donors, including children, healthy adults, and individuals with type 1 or type 2 diabetes. We developed a robust computational biology framework for cell type annotation. Using this framework, we show that α- and ß-cells from children exhibit less well-defined gene signatures than those in adults. Remarkably, α- and ß-cells from donors with type 2 diabetes have expression profiles with features seen in children, indicating a partial dedifferentiation process. We also examined a naturally proliferating α-cell from a healthy adult, for which pathway analysis indicated activation of the cell cycle and repression of checkpoint control pathways. Importantly, this replicating α-cell exhibited activated Sonic hedgehog signaling, a pathway not previously known to contribute to human α-cell proliferation. Our study highlights the power of single-cell RNA-seq and provides a stepping stone for future explorations of cellular heterogeneity in pancreatic endocrine cells.
Assuntos
Ilhotas Pancreáticas/citologia , Ilhotas Pancreáticas/metabolismo , Transcriptoma/genética , Ciclo Celular/genética , Ciclo Celular/fisiologia , Proliferação de Células/genética , Proliferação de Células/fisiologia , Biologia Computacional/métodos , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Células Secretoras de Glucagon/citologia , Células Secretoras de Glucagon/metabolismo , Humanos , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/metabolismo , Microfluídica/métodos , Transdução de Sinais/genética , Transdução de Sinais/fisiologiaRESUMO
Islet-1 (Isl-1) is essential for the survival and ensuing differentiation of pancreatic endocrine progenitors. Isl-1 remains expressed in all adult pancreatic endocrine lineages; however, its specific function in the postnatal pancreas is unclear. Here we determine whether Isl-1 plays a distinct role in the postnatal ß-cell by performing physiological and morphometric analyses of a tamoxifen-inducible, ß-cell-specific Isl-1 loss-of-function mouse: Isl-1(L/L); Pdx1-CreER(Tm). Ablating Isl-1 in postnatal ß-cells reduced glucose tolerance without significantly reducing ß-cell mass or increasing ß-cell apoptosis. Rather, islets from Isl-1(L/L); Pdx1-CreER(Tm) mice showed impaired insulin secretion. To identify direct targets of Isl-1, we integrated high-throughput gene expression and Isl-1 chromatin occupancy using islets from Isl-1(L/L); Pdx1-CreER(Tm) mice and ßTC3 insulinoma cells, respectively. Ablating Isl-1 significantly affected the ß-cell transcriptome, including known targets Insulin and MafA as well as novel targets Pdx1 and Slc2a2. Using chromatin immunoprecipitation sequencing and luciferase reporter assays, we found that Isl-1 directly occupies functional regulatory elements of Pdx1 and Slc2a2. Thus Isl-1 is essential for postnatal ß-cell function, directly regulates Pdx1 and Slc2a2, and has a mature ß-cell cistrome distinct from that of pancreatic endocrine progenitors.