AKR1C3 protects cardiomyocytes against hypoxia-induced cell apoptosis through the Nrf-2/NF-κB pathway.

Hypoxia-induced apoptosis plays a critical role in the progression of various cardiac diseases, such as heart failure and acute myocardial infarction (AMI). Aldosterone reductase 1C3 (AKR1C3), a member of the aldo-keto reductase superfamily, participates in the metabolism of steroid hormones and redox reactions in vivo. Imbalances in prostaglandin levels have been linked to coronary events. However, the function and molecular mechanism by which AKR1C3 influences AMI are not yet fully understood. This study aims to investigate the role of AKR1C3 in hypoxia-induced myocardial cell damage and elucidate its mechanism. Our findings reveal that a hypoxic microenvironment triggers cardiomyocyte apoptosis and elevates AKR1C3 expression in H9C2 and AC16 cells, as well as in cardiac tissue from rats and mice with AMI. The overexpression of AKR1C3 promotes cardiomyocyte proliferation and cell vitality, whereas the silencing of AKR1C3 exerts the opposite effects in vitro. AKR1C3 protects cardiomyocytes against hypoxia-induced cell apoptosis by reducing ROS levels, preventing mitochondrial damage, and maintaining the oxygen consumption rate (OCR) and ATP production; conversely, AKR1C3 knockdown leads to adverse outcomes. Moreover, the application of a ROS inhibitor (MitoQ10) mitigates the increase in mitochondrial ROS in cardiomyocytes induced by AKR1C3 knockdown under hypoxic conditions. Mechanically, AKR1C3 increases Nrf-2 expression through the ubiquitin-proteasome pathway in cardiomyocytes and subsequently inhibits the NF-κB signaling pathway, thereby inhibiting Bax/caspase-3 signaling. Collectively, these results suggest that AKR1C3 prevents hypoxia-induced cardiomyocyte injury by modulating the Nrf-2/NF-κB axis, suggesting new insights into the mechanisms underlying myocardial protection.