Astragaloside IV enhances GATA-4 mediated myocardial protection effect in hypoxia/reoxygenation injured H9c2 cells

Abstract

Background and aimThe transcription factor GATA-4 plays an important role in myocardial protection. Astragaloside IV (Ast-IV) was reported with the effects on improving cardiac function after ischemia. In this study, we explored how Ast-IV interacts with GATA-4 to protect myocardial cells H9c2 against Hypoxia/Reoxygenation (H/R) stress. Methods and resultsH9c2 cells were cultured under the H/R condition. Various cell activity and morphology assays were used to assess the rates of apoptosis and autophagy. In these H/R injured H9c2 cells, increased apoptosis (P < 0.01) and autophagosome number (P < 0.01) were observed, and the addition of Ast-IV ameliorated this tendency. Mechanistically, we used the RT-qPCR and Western blot to evaluate the expressions of various molecules. The results showed that Ast-IV treatment upregulated gene expression of GATA-4 (P < 0.01) and the survival factors (Bcl-2, P < 0.05; p62, P < 0.01), but suppressed apoptosis and autophagy related genes (PARP, Caspase-3, Beclin-1, and LC3-II; All P < 0.01). Furthermore, overexpressing of GATA-4 by its agonist phenylephrine can also protect H/R injured H9c2 cells, and the addition of Ast-IV further enhanced this protection of GATA-4. In contrast, silencing GATA-4 expression abolished the H/R protection of Ast-IV, which demonstrated that the myocardial protection of Ast-IV is mediated by GATA-4. Lastly, along with GATA overexpression, enhanced interactions between Bcl-2 and Beclin-1 were detected by Chromatin immunoprecipitation (P < 0.01). ConclusionAst-IV rescued the H/R injury induced apoptosis and autophagy in H9c2 cells. Ast-IV treatment can stimulate the overexpression of GATA-4, and further enhanced the myocardial protection effect of GATA-4.