Abstract
Cardiovascular disease is a severe threat health worldwide, and circRNAs have been shown to be correlated with the development of cardiovascular disease. Expression of circ-ITCH and miR-17a-5p was evaluated by RT-qPCR. Cell viability was measured using CCK-8. Flow cytometry was applied to measure apoptosis rate. Binding between miR-17-5p and circ-ITCH was detected via luciferase reporter assays. Levels of ATP in cells were examined with ATP testing. Western blot was used to evaluate apoptosis-related proteins and proteins in Wnt/β-catenin signalling pathway. H2O2 induced apoptosis of H9c2 cells and lowered cell viability as well as ATP levels and circ-ITCH expression. After overexpression, circ-ITCH enhanced cell viability and ATP concentration. Meanwhile, apoptosis was inhibited. MiR-17-5p was the target of circ-ITCH as evidenced by luciferase report assays, with higher expression in H2O2-induced H9c2 cells. Knockdown of miR-17-5p could promote cell viability and level of ATP and curb apoptosis and p53 and PARP expression. Moreover, overexpressed miR-17-5p could reverse the function of upregulated circ-ITCH. Wnt3a, Wnt5a and β-catenin in Wnt/β-catenin signalling pathway were increased after H2O2 induction. Suppression of Wnt/β-catenin signalling pathway could initiate the process of injury in H9c2 cells. Circ-ITCH could protect myocardial cells from injuries caused by H2O2 by suppressing apoptosis while miR-17-5p played a reverse role, which could upregulate apoptosis and inhibit cell viability via Wnt/β-catenin signalling pathway.