Mitochondria Are Involved in Ferroptosis Induced by Cardiac Ischemia‐Reperfusion in Rats

Abstract

Cardiac ischemia/reperfusion injury (IRI) activates several cell death mechanisms, the priority of which depends on the severity and duration of ischemia. Recently, ferroptosis, an iron dependent mechanism of regulated cell death, was discovered to participate in cardiac IRI; however, mechanisms underlying ferroptotic signaling in the heart remain unknown. Mitochondria as the main source of ROS and ATP play a central role in cell death, especially in high energy consuming organs such as the heart. Here, we investigated the role of mitochondria in IRI‐induced ferroptosis in the rat heart. Isolated and Langendorff‐mode perfused rat hearts underwent 25‐min of global ischemia followed by 60‐min reperfusion in the presence and absence of the anti‐ferroptotic agents, ferrostatin‐1 (Fer‐1, 1 μM) and liproxstatin‐1 (Lip‐1, 0.2 μM). The compounds were present in the perfusion media 10 min prior to ischemia and throughout the entire period of reperfusion. Cardiac hemodynamic parameters including the left ventricular development pressure (LVDP), heart rate, and rates of contractility/relaxation were monitored continuously whereas LDH activity in the cardiac effluent was determined at reperfusion. Respiration rates, ROS production, and swelling were analyzed in mitochondria isolated from the heart at the end of reperfusion. Results showed that hearts treated with Fer‐1 and Lip‐1 had significantly higher post‐ischemic recovery of cardiac function than the control group (LVDP: 85% and 82%, respectively vs. 34%, p<0.05 for both). LDH release was reduced by ~50 % in the hearts treated with Fer‐1 and Lip‐1. A significant increase in the state 3 respiration rate and respiratory control index for mitochondrial ETC complex I was found in Fer‐1‐ or Lip‐1‐treated hearts. Likewise, Fer‐1 and Lip‐1 significantly reduced IRI‐induced basal and Ca2+‐induced mitochondrial ROS production. We observed no difference in Ca2+‐induced mitochondrial swelling between control and treated groups. IR‐induced ferroptotic phospholipid signaling was attenuated in the presence of Fer‐1 or Lip‐1. In conclusion, our study demonstrates that ferroptosis affect cardiac/mitochondrial function during IRI suggesting that mitochondria can be engaged in ferroptotic signaling in the heart.Support or Funding InformationThis study was supported by the NIH NIGMS (Grants SC1GM128210 and R25GM061838‐18).