Background

Cardiac hypertrophy is a common pathological process in many cardiac diseases, and persistent cardiac hypertrophy is the main cause of heart failure and sudden cardiogenic death. Thus, it is essential to elucidate the mechanism of cardiac hypertrophy to ensure better prevention and treatment.

Methods

The Human cardiac myocytes (HCMs) were incubated with 100 nmol/L Ang II (Sigma) for 48 hours to induce the in vitro cardiomyocyte hypertrophy model. The [(3H])-leucine incorporation assay was used to evaluate cardiomyocytes hypertrophy. The activities of oxidative stress related enzymes superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA) and nitric oxide (NO) were detected using corresponding detection kits following standard protocol. Targeting relationship was verified through Bioinformatics analysis and luciferase reporter gene assay. The morphological change of cardiomyocyte was observed through immunofluorescence staining. Expressions of message ribonucleic acid (mRNA) and proteins were detected by quantitative real-time polymerase chain reaction and western blot, respectively.

Results

In our study, the suppressed expression of micro ribonucleic acid (miRNA)-129-5p and the elevated expression of kelch-like ECH-associated protein 1 (keap-1) were found in the angiotensin II (Ang II)-induced cardiomyocyte hypertrophy model. MiR-129-5p effectively mimics suppressed Ang II-induced hypertrophic responses and oxidative stress. The results also showed that keap-1 was a target of miR-129-5p, and that the miR-129-5p inhibitor promoted cardiomyocyte hypertrophy and oxidative stress by elevating keap-1. Additionally, small interfering RNA (siRNA)-keap-1 activated the nuclear factor erythroid2-related factor 2 (Nrf2) pathway, while the miR-129-5p inhibitor inactivated the Nrf2 pathway by further elevating keap-1. The addition of the Nrf2 pathway activator NK-252 largely weakened the promoting effects of the miR-129-5p inhibitor on the progression of cardiomyocyte hypertrophy by suppressing oxidative stress.

Conclusions

In general, the results indicate that the overexpression of miRNA-129-5p protects against cardiomyocyte hypertrophy by targeting keap-1 via the Nrf2 pathway.