MicroRNA-29b-3p Targets SPARC Gene to Protect Cardiocytes against Autophagy and Apoptosis in Hypoxic-Induced H9c2 Cells

MicroRNAs participate in the regulation of abnormal cardiomyocyte apoptosis and autophagy, which leads to heart failure (HF). Lower miR-29b-3p levels were found in HF patients in this study. However, the role of miR-29b-3p in the molecular pathogenesis of HF remains unclear. Hypoxia-stimulated H9c2 cells were used an in vitro model of HF. It was found that hypoxia stimulation decreased the miR-29b-3p expression and enhanced cell apoptosis and autophagy response in H9c2 cells. While the effects of hypoxia on cell apoptosis and autophagy were reversed by miR-29b-3p transfection, especially 100 nM. The secreted protein acidic and rich in cysteine (SPARC), predicted as a direct target of miR-29b-3p, aggravated the hypoxia-induced cells apoptosis, autophagy, and TGFβ1/Smad3 activation. While the changes were dramatically reversed by miR-29b-3p. Taken together, our data suggest that miR-29b-3p plays an important role in the progression of HF through targeting SPARC and regulating TGFβ1/Smad3 pathway.