MicroRNA-7a regulates pancreatic ? cell function.

ABSTRACT: Dysfunctional microRNA (miRNA) networks contribute to inappropriate responses following pathological stress and are the underlying cause of several disease conditions. In pancreatic ? cells, miRNAs have been largely unstudied and little is known about how specific miRNAs regulate glucose-stimulated insulin secretion (GSIS) or impact the adaptation of ? cell function to metabolic stress. In this study, we determined that miR-7 is a negative regulator of GSIS in ? cells. Using Mir7a2 deficient mice, we revealed that miR-7a2 regulates ? cell function by directly regulating genes that control late stages of insulin granule fusion with the plasma membrane and ternary SNARE complex activity. Transgenic mice overexpressing miR-7a in ? cells developed diabetes due to impaired insulin secretion and ? cell dedifferentiation. Interestingly, perturbation of miR-7a expression in ? cells did not affect proliferation and apoptosis, indicating that miR-7 is dispensable for the maintenance of endocrine ? cell mass. Furthermore, we found that miR-7a levels are decreased in obese/diabetic mouse models and human islets from obese and moderately diabetic individuals with compensated ? cell function. Our results reveal an interconnecting miR-7 genomic circuit that regulates insulin granule exocytosis in pancreatic ? cells and support a role for miR-7 in the adaptation of pancreatic ? cell function in obesity and type 2 diabetes.

SUBMITTER: Latreille M 

PROVIDER: S-EPMC4038573 | biostudies-literature | 2014 Jun

REPOSITORIES: biostudies-literature