白藜芦醇通过激活PKA-PLIN2通路促进HepG2细胞脂滴脂解

目的 明确围脂滴蛋白2(perilipinin-2,PLIN2)在白藜芦醇(resveratrol,RSV)改善脂肪变性HepG2细胞脂滴代谢中的作用机制.方法 0.2 mmol/L棕榈酸处理HepG2细胞24 h,建立肝细胞脂肪变性模型.使用0、10、20、40、80 μmol/L RSV及转染PLIN2 siRNA或PKI过表达质粒后,再用40 μmol/L RSV干预24 h,油红O染色检测脂滴形成情况,酶法检测细胞内甘油三酯以及细胞外游离甘油含量,Western blot检测PLIN2蛋白表达,实时定量PCR检测PLIN2 mRNA表达.结果 RSV可以降低脂肪变性HepG2细胞脂滴蓄积程度,促进脂滴的脂解.RSV可以通过促进磷酸化增强PKA的活性,并呈浓度依赖性地上调PLIN2 mRNA和蛋白表达水平(P＜0.05).抑制PKA活性或下调PLIN2表达后,RSV促进脂肪变性HepG2细胞脂解的作用显著减弱(P＜0.05).结论 RSV通过激活PKA-PLIN2通路促进HepG2细胞脂滴脂解过程,从而可能改善非酒精性脂肪性肝病.

Resveratrol improves lipid droplet lipolysis via up-regulating PKA-PLIN2 pathway in HepG2 cells

Objective Elucidate the role of perilipinin-2 (PLIN2) in RSV improving lipid droplet metabolism in liver steatosis in HepG2 cells.Methods HepG2 cells were incubated with 0.2 mmol/L of palmitic acid (PA) for 24 h to set up a hepatic steatosis model.The cells were then treated with or without a series of concentrations (10,20,40 and 80 μmol/L) of RSV,or transfected with PLIN2 siRNA or PKI overexpression plasmid,40 μmol/L RSV was added for another 24 h.Hepatic lipid accumulation was assayed by Oil Red O staining.Contents of triglyceride in cells and free glycerin glycerol in culture medium were detected by Enzyme method.The protein and mRNA levels of PLIN2 were measured by Western blot assay and real-time quantitative PCR,respectively.Results RSV reduced the lipid droplet accumulation and increased the lipolysis in PA-induced HepG2 cells.Additionally,RSV increased the activity of PKA by phosphorylation and dose-dependently raised the mRNA and protein levels of PLIN2 (P ＜ 0.05).The promoting effect of RSV on the lipolysis was significantly reduced by the inhibition of PKA activity and the down-regulation of PLIN2 (P ＜ 0.05).Conclusion RSV promotes lipid droplet lipolysis by activating PKA-PLIN2 pathway in HepG2 cells,and may attenuate non-alcoholic fatty liver disease.