Fetal PGC-1 alpha Overexpression Programs Adult Pancreatic beta-Cell Dysfunction

Adult beta-cell dysfunction, a hallmark of type 2 diabetes, can be programmed by adverse fetal environment. We have shown that fetal glucocorticoids (GCs) participate in this programming through inhibition of beta-cell development. Here we have investigated the molecular mechanisms underlying this regulation. We showed that GCs stimulate the expression of peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1 alpha), a coregulator of the GCs receptor (GR), and that the overexpression of PGC-1 alpha represses genes important for beta-cell development and function. More precisely, PGC-1 alpha inhibited the expression of the key beta-cell transcription factor pancreatic duodenal homeobox 1 (Pdx1). This repression required the GR and was mediated through binding of a GR/PGC-1 alpha complex to the Pdx1 promoter. To explore PGC-1 alpha function, we generated mice with inducible beta-cell PGC-1 alpha overexpression. Mice overexpressing PGC-1 alpha exhibited at adult age impaired glucose tolerance associated with reduced insulin secretion, decreased beta-cell mass, and beta-cell hypotrophy. Interestingly, PGC-1 alpha expression in fetal life only was sufficient to impair adult beta-cell function whereas beta-cell PGC-1 alpha overexpression from adult age had no consequence on beta-cell function. Altogether, our results demonstrate that the GR and PGC-1 alpha participate in the fetal programming of adult beta-cell function through inhibition of Pdx1 expression. Diabetes 62:1206-1216, 2013