Epigenetic regulation by histone acetyltransferase (HAT) is associated with various biological processes and the progression of diseases, including nonalcoholic fatty liver disease (NAFLD). The objective of this study was to investigate whether the hypolipidemic properties of black mulberry (Morus atropurpurea Roxb.) fruit extract (BME) contribute toward protection against NAFLD by HAT inhibition. HepG2 cells were treated with oleic and palmitic acids to induce lipid accumulation, which was significantly attenuated by the treatment with BME at 50 and 100 μg/mL. BME also markedly reduced the expression of proteins associated with lipogenesis, which was attributed to the BME-mediated downregulation of lipogenic genes in HepG2 cells. BME significantly inhibited in vitro total HAT and p300 activities. In addition, BME suppressed total acetylated lysine as well as specific histone acetylation of proteins H3K14 and H3K27 in HepG2 cells. Mice were then fed with either a chow diet or western diet (WD), with or without BME (1%, w/w) supplementation, for 12 weeks to confirm hypolipidemic activity of BME. BME attenuated serum nonesterified fatty acids and low-density lipoprotein (LDL) cholesterol levels, which was likely associated with the downregulation of hepatic lipogenic gene expression in WD-fed obese mice. Taken together, the hypolipidemic activity of BME was observed in HepG2 cells treated with fatty acids as well as in livers of obese mice, and the hepatoprotection of BME is likely associated with the inhibition of acetylation. Further investigation is warranted to determine whether BME can be developed into an efficacious dietary intervention to attenuate the progression of NAFLD by epigenetic regulation in clinical settings.
Keywords: HepG2 cells; black mulberry; histone acetyltransferase; nonalcoholic fatty liver disease; western diet.