The HMGB1-IL-17A axis contributes to hypoxia/reoxygenation injury via regulation of cardiomyocyte apoptosis and autophagy

Abstract

Both the high-mobility group box 1 protein (HMGB1) and interleukin (IL)-17A serve important roles in myocardial ischemia and reperfusion injury. The purpose of the present study was to evaluate whether HMGB1 could induce IL-17A secretion and lead to cardiomyocyte hypoxia/reoxygenation (H/R) injury. Neonatal rat cardiomyocytes were treated with HMGB1-neutralizing antibody, IL-17A-neutralizing antibody, recombinant HMGB1 (rHMGB1) and recombinant IL-17A (rIL-17A), respectively. Cell viabilities, lactate dehydrogenase and creatine kinase levels were measured. Apoptotic cells were assessed by flow cytometry. The expression of HMGB1, IL-17A, microtubule-associated proteins 1A/1B light chain 3B (LC3), Beclin-1, B-cell lymphoma (Bcl)-2 and Bcl-2-associated X protein were assessed by western blot analysis. The results demonstrated that HMGB1 significantly increased the expression of IL-17A. HMGB1 or IL-17A antibody significantly ameliorated H/R-induced cell injury and improved the cell viability. In contrast, rHMGB1 or rIL-17A aggravated cell injury and inhibited the cell viability. Furthermore, cardiomyocytes were treated with HMGB1 or IL-17A antibody significantly increased Bcl-2 protein expression and had fewer apoptotic cells, whereas rHMGB1 or rIL-17A-treated cardiomyocytes markedly decreased Bcl-2 protein expression and had more apoptotic cells. Moreover, HMGB1 or IL-17A antibodies significantly inhibited H/R induced autophagy dysfunction (as determined by the inhibition of Beclin-1 expression, a lower ratio of LC3-II to LC3-I), whereas rHMGB1 or rIL-17A may promote cardiomyocyte autophagy. Together, these results suggested that the HMGB1-IL-17A axis contributes to H/R injury via regulation of cardiomyocyte apoptosis and autophagy.