MiR-24-3p Attenuates Doxorubicin-induced Cardiotoxicity via the Nrf2 Pathway in Mice

The nuclear factor erythroid 2 (NFE2)-related factor 2 (Nrf2) is associated with doxorubicin (DOX)-induced cardiac injury. It has been reported that microRNA-24-3p (miR-24-3p) may regulate the Keapl by mRNA degradation, whereas Keapl can suppress the activation of Nrf2. However, the role of miR-24-3p in DOX-related cardiotoxicity remains unclear.

The mice receiving DOX were used as cardiac injury model. In this study, an adenoassociated virus 9 system was used to deliver miR-24-3p or miR-scramble to mice hearts. The echocardiographic and hemodynamic analyses were used to evaluate the effects of miR-24-3p on cardiac function under DOX stimulation. ELISA and RT-PCR were used to detect protein or mRNA expressions associated with cardiac injury, inflammation response, apoptosis and oxidative stress. Western Blot were used for quantitative analysis of the roles of miR-24-3p in regulating Nrf2 expression. H9C2 cells used to verify the role of miR-24-3p in vitro.

We found that miR-24-3p mRNA was significantly decreased in DOX-treated mice and cardiomyocytes. Overexpression of miR-24-3p blocked cardiac injury caused by DOX injection, as reflected by the reduction in the levels of cardiac troponin I, creatinine kinase isoenzyme MB and the N-terminal pro brain natriuretic peptide. Furthermore, miR-24-3p reduced oxidative stress and cell loss without affecting the inflammation response. As expected, we found that Nrf2 was upregulated by miR-24-3p supplementation, and that the protective efforts of miR-24-3p supplementation were abolished when Nrf2 was silenced.

The results from this study suggest that miR-24-3p protects cardiomyocytes against DOX-induced heart injury via activation of the Nrf2 pathway. miR-24-3p supplementation may be a novel strategy to counteract the cardiac side effects of DOX treatment.