Resveratrol Modulates Apoptosis and Autophagy Induced by High Glucose and Palmitate in Cardiac Cells
Background/Aims: Diabetic cardiomyopathy is associated with increased apoptosis and suppressed autophagy in cardiac cells. The polyphenol resveratrol has shown beneficial effects in various cardiovascular diseases. This study investigated if resveratrol protected cardiac cells by modulating apoptosis and autophagy in the context of diabetes. Methods: H9c2 cardiac myoblast cells were exposed to high glucose combined with palmitate. Autophagy was evaluated by estimating LC3-II/I ratio, P62 protein levels, and LC3 fluorescent puncta. Apoptosis was assessed by using terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL), flow cytometry, and analysis of the protein expression of apoptotic markers (cleavage of caspase-3 and PARP). Results: High glucose and palmitate suppressed autophagic activity and exacerbated apoptotic cell death in cardiac myoblast cells. Resveratrol restored autophagy and attenuated apoptosis in cells upon diabetic stimuli. Moreover, resveratrol activated AMPK and JNK1, thereby suppressing mTOR and its downstream effectors p70S6K1 and 4EBP1, as well as disrupting the Beclin1–Bcl-2 complex. Conclusion: Resveratrol protects cardiac cells by regulating the switch between autophagy and apoptotic machinery under diabetic conditions, which is attributed by AMPK-mediated phosphorylation of mTORC1/p70S6K1/4EBP1 and JNK-mediated dissociation of Beclin1-Bcl-2. Our study suggests that autophagy may be an important target for resveratrol in the treatment of diabetic cardiomyopathy.