The Function And Mechanism Of Sirt3 In RSV Regulating Mitochondrial Function In Steatosis Of HepG2 Cells

Nonalcoholic fatty liver disease(NAFLD)has been one of the main global public health problems,and the morbidity rate goes up continuosly over years.Nonalcoholic steatohepatitis(NASH),a more typical form of NAFLD,with high possibility to become cirrhosis or hepatocllular carcinoma.However,there are no ideal medicine for prevention and treatment of patients with NASH.Hepatocyte damage,inflammation and fibration are several characters of NASH.The mitochondrial dysfunction and oxidative stress leading to hepatocellular injury were the centre process of NASH developing.There were a lot of evidences that RSV could significant reduce the level of TG and ROS,reduce oxidative stress reaction,Maintain the mitochondrial membrane potential and improve mitochondrial respiratory capacity in steatosis of Hep G2 cell.Animal experiments found that RSV could significantly reduce inflammatory reaction,and liver fibrosis in rats and mice fed by high-fat diet.Resveratrol is a polyphenolic compound with antioxidant capacity that shows beneficial effects on down-regulation of inflammatory mediators and metabolic disorders.Sirtuin(Sirt3)plays a key role in adjusting mitochondrial energy metabolism,and has closely relation to ROS generation and clearness via modifying kinds of mitochondrial protein by deacetylation.It is still under investigating whether RSV could improve mitochondrial function,restrain cell oxidative stress damage by adjusting Sirt3 protein expression and activity.This research established the hepatic steatosis cell model following palmitic acid(PA)stimulation in cultured HepG2 cells.Firstly,we investigated the important role of Sirt3 in RSV improving steatosis of hepatic cells using western blotting,si RNA and relevant kits.Then we explored the role of PARP1-AMPK signaling pathway in RSV regulating the expression and activity of Sirt3 in HepG2 cell using special inhibitor and stimulator.The main results and findings are as follows:(1)0.2m M palmitic acid(PA)could increase level of ROS?IL-6?TNF-?,decrease mitochondrial function,and reduce the accumulation of intracellular TG in HepG2 cells.40?M RSV could significantly improve mitochondrial respiratory chain complex enzymes and mitochondrial respiratory capacity,significantly suppress the level of TG,ROS,IL-6 and TNF-? in HepG2 cells induced by PA.These results suggest that RSV could inhibit ROS generation and reduce liver cell oxidative stress injury and improve mitochondrial function,and then decrease the lipid accumulation in steatosis of Hep G2 cells.(2)RSV up-regulated the expression and activity of Sirt3 in steatosis of Hep G2 cells.Furthermore,Sirt3 inhibitor(3-TYP),as well as Sirt3 siRNA significantly attenuated RSV-induced the improving effects of mitochondrial function and steatosis.These results indicated that the effects of RSV on mitochondrial function and steatosis were dependent on Sirt3.(3)RSV also increased the expression of PARP1 and p-AMPK.RSV-induced up-regulation of Sirt3 in HepG2 cells was abolished in the presence of inhibitor of AMPK(compound C),as well as PARP1 and AMPK siRNA transfection,indicating that the effects of RSV on the expression and activity of Sirt3 were dependent on PARP1 and AMPK.In summary,RSV could activate the signal pathway of PARP1/AMPK to promote the expression and activity of Sirt3,inhibit ROS generation,reduce cell oxidative stress damage,improve cell mitochondrial function,and then improve the HepG2 cell lipid accumulation.This study has important theoretical and application prospects for the prevention and treatment of NAFLD.