B-cell translocation gene-2 increases hepatic gluconeogenesis via induction of CREB

Abstract

Hepatic gluconeogenesis is mediated by the network of transcriptional factors and cofactors. Here, we show that B-cell translocation gene-2 (BTG2) plays a crucial cofactor in hepatic gluconeogenesis via upregulation of the cyclic AMP (cAMP) response element binding (CREB) in hepatocytes. cAMP/dexamethasone (Dex) significantly increased BTG2 and other gluconeogenic genes such as Nur77, phosphoenolpyruvate carboxykinase (PEPCK), and glucose-6-phosphatase (G6Pase) in hepatocytes. In contrast, insulin treatment completely blocks their expressions. Interestingly, overexpression of BTG2 using adenoviral system (Ad-BTG2) significantly elevated hepatic glucose production via the increase of transcriptional activity and gene expression of CREB, PEPCK, and G6Pase in hepatocytes, suggesting that BTG2 is the key player on hepatic glucose production. Physiological interaction studies demonstrated that BTG2 correlated CREB recruitment on the PEPCK gene promoter via a direct interaction. Finally, knockdown of endogenous BTG2 expression markedly inhibits the cAMP/Dex-induced transcriptional activity of gluconeogenic genes and glucose production in hepatocytes. Overall, the present study provides us with a novel molecular mechanism of BTG2-mediated induction of hepatic gluconeogenesis and suggests that BTG2 plays an important role in hepatic glucose metabolism.