Epigallocatechin-3-Gallate Inhibits Ethanol-Induced Apoptosis Through Neurod1 Regulating CHOP Expression in Pancreatic β-Cells

Abstract

Epiga-llocatechin-3-gallate (EGCG) is one kind of polyphenol abundant extracted from green tea which has a potent antidiabetic activity. However, the molecular mechanisms mediating the protection procession of EGCG are still unclear. The aim of this study was to investigate the protective effect of EGCG on pancreatic β-cells exposed to ethanol and the possible underlying mechanisms. To observe the effect of EGCG, we assessed apoptosis in βTC-6 and INS-1 cells, which were in complete medium containing 60 mM ethanol, or coincubation with different concentration of EGCG. We also evaluated the roles of Neurod1 in CHOP expression and ethanol-mediated damage through plasmid overexpression. Treatment with EGCG decreased CHOP expression and apoptosis, whereas its treatment increased Neurod1 expression in ethanol-treated βTC-6 and INS-1 cells. Overexpression of Neurod1 caused the decrease of CHOP expression and apoptosis in ethanol-treated cells. Furthermore, Neurod1 inhibited CHOP expression by deacetylation of Histone H4 at the CHOP gene promoter. In addition, EGCG partially restores the activity of Neurod1 binding to CHOP promoter in ethanol-treated cells. In conclusion, EGCG protected β-cell against ethanol-induced β-cell apoptosis by Neurod1 regulating CHOP expression. Anat Rec, 299:573-582, 2016.