Abstract
The histone acetyltransferases CREB-binding protein (CBP) and its paralogue p300 are transcriptional coactivators which are essential for a multitude of signaling pathways and energy homeostasis. However, the role of CBP/p300 HAT domain in regulating energy balance is still unclear. Here, C57BL/6 mice fed with either normal chow diet (NCD) or high-fat diet (HFD) were administrated with A-485, a recently reported selective inhibitor of CBP/p300 HAT activity for 1 week and the metabolic change was analyzed. The white adipose tissue (WAT) weight and adipocyte size were reduced in A-485-administrated mice, with decreased expressions of lipogenic genes and transcriptional factors. In the liver of A-485-treated mice, the lipid content and lipogenic gene expressions were lowered while the binding of forkhead box O1 (FOXO1) to glucose-6-phosphatase (G6Pc) promoter was reduced, leading to decreased expression of G6Pc. In primary mouse hepatocytes, A-485 abolished cAMP-elicited mRNA expressions of key gluconeogenic enzymes and promoted FOXO1 protein degradation via increasing its ubiquitination. Thus, A-485 inhibits lipogenesis in WAT and liver as well as decreases hepatic glucose production via preventing FOXO1 acetylation, leading to its protein degradation through a proteasome-dependent pathway. The specific inhibition of CBP/p300 HAT will provide a novel therapeutic approach for metabolic diseases.