# Nrf2 de-SUMOylation alleviates myocardial ischemia-reperfusion injury (MIRI) by attenuating myocardial ferroptosis in mice

## TL;DR

Blocking Nrf2 SUMOylation reduces heart damage during reperfusion by preventing a type of cell death called ferroptosis in mice.

## Contribution

This study identifies Nrf2 de-SUMOylation as a novel therapeutic target for mitigating myocardial ischemia-reperfusion injury.

## Key findings

- Nrf2 de-SUMOylation reduces myocardial ferroptosis and severity of MIRI in mice.
- Nrf2 de-SUMOylation decreases Transferrin receptor (Tfr) expression, mitigating ferroptosis in cardiomyocytes.
- Liproxstatin-1, a ferroptosis inhibitor, attenuates differences in MIRI between wild-type and Nrf2 K110R mice.

## Abstract

Reperfusion, an essential therapeutic strategy for salvaging ischemic myocardium in ischemic heart disease, paradoxically exacerbates myocardial injury. Ferroptosis is a pivotal mechanism underlying myocardial ischemia-reperfusion injury (MIRI). Nrf2 can regulate ferroptosis, which could undergo SUMOylation at lysine 110 (K110) and was subsequently de-SUMOylated by Senp1. This study aimed to determine whether Nrf2 de-SUMOylation could mitigate MIRI by inhibiting myocardial ferroptosis.

Nrf2 K110R mice, mimicking Nrf2 de-SUMOylation, were generated. Mice cardiac morphology and function were observed by hematoxylin–eosin staining (HE) and echocardiography under normal and MIRI conditions. Ferroptosis inhibitor liproxstatin-1 (Lip-1) was used to demonstrate ferroptosis participation in Nrf2 de-SUMOylation regulated MIRI. In vitro, SUMO1/sentrin-specific protease 1 Senp1 KO H9C2 cells were subjected to RSL3-induced ferroptosis to explore underlying mechanism.

Nrf2 K110R mice showed normal cardiac morphology and function at baseline. However, de-SUMOylation of Nrf2 alleviated myocardial ferroptosis, resulting in a reduction of MIRI severity in MIRI mice. The administration of Lip-1 attenuated the differences in MIRI between Nrf2 wild-type and K110R mice. Mechanistically, Nrf2 de-SUMOylation was associated with a reduction in Transferrin receptor (Tfr) expression level, thereby mitigating ferroptosis in cardiomyocytes.

This study highlighted the role of Nrf2 SUMOylation in promoting ferroptosis during MIRI and identified Nrf2 de-SUMOylation as a potential therapeutic target for MIRI.