miR‐432‐5p Inhibits the Ferroptosis in Cardiomyocytes Induced by Hypoxia/Reoxygenation via Activating Nrf2/SLC7A11 Axis by Degrading Keap1

Abstract

Early reperfusion into the myocardium after ischemia causes myocardial ischemia–reperfusion (I/R) injury and ferroptosis was involved. Ischemia activates the expression of a series of oxidative stress genes and their downstream regulatory genes, including ferroptosis-related genes such as nuclear factor E2-related factor 2 (Nrf2), glutathione peroxidase 4 (GPX4), and SLC7A11. This study adopted primary cardiomyocytes and I/R in rats to evaluate the ferroptosis and changing of Nrf2-SLC7A11/heme oxygenase-1 (HO-1) in vitro and in vivo. Online analysis tools were used to predict the possible target Kelch-like ECH-associated protein 1 (Keap1) of miR-432-5p. The mimic of miR-432-5p plasmid was constructed to verify the effect of miR-432-5p on ferroptosis. We found that hypoxia/reoxygenation (H/R) in cardiomyocytes and I/R in rats induced lipid peroxidation and ferroptosis in cardiomyocytes. The activation of the Nrf2-SLC7A11/HO-1 pathway protects cardiomyocytes from ferroptosis. Downregulation of miR-432-5p has been confirmed in H/R cardiomyocytes (in vitro) and cardiomyocytes in myocardial infarction rats (in vivo). Upregulation of miR-432-5p inhibited ferroptosis of cardiomyocytes induced by RAS-selective lethal 3 (RSL3), an inhibitor of GPX4 and ferroptosis inducer through decreasing the binding protein of Nrf2, Keap1, which was confirmed by bioinformatics and mutation assay. Knockdown Nrf2 attenuates the protection effect of miR-432-5p on H/R cardiomyocytes. Intravenous delivery of liposome carriers of miR-432-5p remarkably ameliorated cardiomyocyte impairment in the I/R animal model. In conclusion, miR-432-5p inhibits the ferroptosis in cardiomyocytes induced by H/R by activating Nrf2/SLC7A11 axis by degrading Keap1 and is a potential drug target for clinical myocardial infarction treatment.

Ferroptosis, a Regulated Form of Cell Death, as a Target for the Development of Novel Drugs Preventing Ischemia/Reperfusion of Cardiac Injury, Cardiomyopathy and Stress-Induced Cardiac Injury

“…It was reported elsewhere that the HO-1 inhibitor zinc protoporphyrin suppressed isoproterenol-induced myocardial ferroptosis [56]. It was found, in another study, that the cytoprotective and anti-ferroptotic effects of the MiR-432-5p mimic are associated with an increase in the HO-1 level in isolated cardiomyocytes subjected to H/R [57].…”

“…In addition, the miR-432-5p mimic increased HO-1 expression in cardiomyocytes and decreased it in the Kelch-like ECH-associated protein 1 (Keap1) protein level. It was reported that Keap1 is an endogenous inhibitor of Nrf2 [57]. It was found that miR-432-5p-Lipo reduced infarct size by about 30% and inhibited ferroptosis in myocardial tissue in rats with CAO (30 min) and reperfusion (4 h) [57].…”

“…In one study, neonatal rat ventricular cardiomyocytes were exposed to H/R [57]. H/R induced cell death and ferroptosis.…”

“…H/R induced cell death and ferroptosis. An miR-432-5p mimic plasmid increased cell viability and inhibited ferroptosis [57]. The cytoprotective effect of the miR-432-5p mimic was associated with an increase in the expression of nuclear factor erythroid 2-related factor 2 (Nrf2).…”

“…It was reported that Keap1 is an endogenous inhibitor of Nrf2 [57]. It was found that miR-432-5p-Lipo reduced infarct size by about 30% and inhibited ferroptosis in myocardial tissue in rats with CAO (30 min) and reperfusion (4 h) [57]. The investigators concluded that the miR-432-5p mimic inhibits ferroptosis through the activation of Nrf2 and HO-1 expression in cardiomyocytes and the inhibition of Keap1 expression [57].…”