Atf3/Pdx-1/Hdac1 Axis Prompts Metabolic Syndrome [Gene Regulation]

Chronic ethanol consumption induces pancreatic β-cell dysfunction through glucokinase (Gck) nitration and down-regulation, leading to impaired glucose tolerance and insulin resistance, but the underlying mechanism remains largely unknown. Here, we demonstrate that Gck gene expression and promoter activity in pancreatic β-cells were suppressed by chronic ethanol exposure in vivo and in vitro, whereas expression of activating transcription factor 3 (Atf3) and its binding to the putative Atf/Creb site (from −287 to −158 bp) on the Gck promoter were up-regulated. Furthermore, in vitro ethanol-induced Atf3 inhibited the positive effect of Pdx-1 on Gck transcriptional regulation, enhanced recruitment of Hdac1/2 and histone H3 deacetylation, and subsequently augmented the interaction of Hdac1/Pdx-1 on the Gck promoter, which were diminished by Atf3 siRNA. In vivo Atf3-silencing reversed ethanol-mediated Gck down-regulation and β-cell dysfunction, followed by the amelioration of impaired glucose tolerance and insulin resistance. Together, we identified that ethanol-induced Atf3 fosters β-cell dysfunction via Gck down-regulation and that its loss ameliorates metabolic syndrome and could be a potential therapeutic target in treating type 2 diabetes. The Atf3 gene is associated with the induction of type 2 diabetes and alcohol consumption-induced metabolic impairment and thus may be the major negative regulator for glucose homeostasis.

Source: Journal of Biological Chemistry - September 25, 2014 Category: Chemistry Authors: Kim, J. Y., Hwang, J.-Y., Lee, D. Y., Song, E. H., Park, K. J., Kim, G. H., Jeong, E. A., Lee, Y. J., Go, M. J., Kim, D. J., Lee, S. S., Kim, B.-J., Song, J., Roh, G. S., Gao, B., Kim, W.-H. Tags: Molecular Bases of Disease Source Type: research