The transcriptional co-activator PGC-1α up regulates apelin in human and mouse adipocytes

By using pangenomic microarray, we identified apelin as a unique adipokine up regulated by the transcriptional co-activator peroxisome proliferator-activated receptor γ (PPARγ) co-activator 1α (PGC-1α) in human white adipocytes. We investigated its regulation in vitro and in vivo. Overexpression of PGC-1α by adenovirus in human adipocytes induces apelin expression and secretion. Pharmacological induction of cAMP, an upstream regulator of endogenous PGC-1α expression, up regulates apelin gene expression and also apelin secretion in human and mice adipocytes. Moreover, during cold exposure in mice, a physiological situation known to induce both cAMP and PGC-1α, apelin expression in adipocytes and plasma levels were increased. This is the first demonstration that PGC-1α is involved in the regulation of an adipokine gene expression and release.