MiR-208a-3p aggravates autophagy through the PDCD4-ATG5 pathway in Ang II-induced H9c2 cardiomyoblasts

Pathological cardiac hypertrophy is the main determinant of the development of heart failure, for which there is often no effective therapy. The dysregulation of autophagy is implicated in hypertrophy, but the mechanism linking these processes is unclear. In this study, we characterized the regulatory role of miR-208a-3p in autophagy in H9c2 cardiomyoblasts induced by Angiotensin II (Ang II). We found that miR-208a-3p was up-regulated in Ang II-induced H9c2 cardiomyoblasts and in starvation-induced autophagy. The overexpression of miR-208a-3p increased Ang II-induced autophagy, and this was accompanied by the inhibition of programmed cell death protein (PDCD4) and upregulation of autophagy protein 5 (ATG5). A dual-luciferase report assay confirmed the direct binding between miR-208a-3p and PDCD4. PDCD4 knockdown up-regulated autophagy, and its overexpression down-regulated this process. Moreover, the PDCD4-mediated regulation of autophagy was modulated by ATG5. Taken together, these findings indicate that miR-208a-3p promotes autophagy during Ang II-induced hypertrophy and provide a basis for the development of therapies for hypertrophic-induced cardiac dysfunction.