F-box and WD repeat-containing protein 7 ameliorates angiotensin II-induced myocardial hypertrophic injury via the mTOR-mediated autophagy pathway

Myocardial hypertrophy is a common heart disease that is closely associated with heart failure. The expression of F-box and WD repeat-containing protein 7 (FBW7) is significantly downregulated in angiotensin (Ang) II-induced cardiac fibroblasts, suggesting that it may possess an important function in cardiac development. The present study attempted to explore the role of FBW7 in Ang II-induced myocardial hypertrophic injury and its associated mechanism of action. Reverse transcription-quantitative PCR and western blotting were used to determine the expression levels of FBW7 in Ang II-induced H9C2 cells. The expression levels of autophagy-related and mTOR signaling pathway-related proteins were detected using western blotting. Cell viability was assessed using the Cell Counting Kit-8 assay. The apoptosis rate of H9C2 cells was detected using TUNEL assay and western blotting. Cellular hypertrophy and fibrosis were assessed using phalloidin staining and western blotting. Levels of inflammatory factors were examined using ELISA and western blotting, whereas levels of oxidative stress-related markers were detected by corresponding kits. The results indicated that FBW7 expression was downregulated in Ang II-induced H9C2 cells. FBW7 upregulation enhanced the expression levels of autophagy-related proteins and activated mTOR-mediated cellular autophagy. FBW7 overexpression promoted the cell viability, inhibited Ang II-induced apoptosis, cellular hypertrophy and fibrosis in H9C2 cells via the autophagic pathway, as well as inflammation and oxidative stress. Overall, the data indicated that FBW7 overexpression ameliorated Ang II-induced hypertrophic myocardial injury via the mTOR-mediated autophagic pathway.