Abstract
Ferroptosis is a recently identified iron-dependent programmed cell death with lipid peroxide accumulation and condensation and compaction of mitochondria. A recent study indicated that ferroptosis plays a pivotal role in ischemic cardiac injury with the mechanisms remain largely unknown. This study demonstrates that when an iron overload occurs in the ischemia/reperfusion cardiac tissues, which initiates myocardial ferroptosis, the expression levels of mitochondrial inner membrane protein MPV17 are reduced. Overexpression of MPV17 delivered via adenovirus significantly reduced ferroptosis in both cardiomyocytes with high levels of iron and cardiac I/R tissues. Mitochondrial glutathione (mtGSH), crucial for reactive oxygen species scavenging and mitochondrial homeostasis maintenance, is depleted in myocardial ferroptosis caused by iron overload. This mechanistic study shows that MPV17 can increase mitochondrial glutathione levels through maintaining the protein homeostasis of SLC25A10, which is a mitochondrial inner-membrane glutathione transporter. The absence of MPV17 in iron overload resulted in the ubiquitination-dependent degradation of SLC25A10, leading to impaired mitochondrial glutathione import. Moreover, we found that MPV17 was the targeted gene of Nrf2, which plays a pivotal role in preventing lipid peroxide accumulation and ferroptosis. The decreased expression levels of Nrf2 led to the inactivation of MPV17 in iron overload-induced myocardial ferroptosis. In summary, this study demonstrates the critical role of MPV17 in protecting cardiomyocytes from ferroptosis and elucidates the Nrf2-MPV17-SLC25A10/mitochondrial glutathione signaling pathway in the regulation of myocardial ferroptosis.