Estrogen mitigates ischemia-reperfusion injury by inhibiting cardiomyocyte ferroptosis through the downregulation of PHLDA3 expression

Abstract

Ferroptosis represents a significant target for mitigating myocardial ischemia-reperfusion (I/R) injury. Existing literature indicates that estrogen (17β-estradiol, E2) can alleviate such injuries through various pathways. However, the specific mechanisms by which E2 may confer protection against myocardial I/R injury through the inhibition of ferroptosis remain to be fully elucidated. This study employed a mouse model of left anterior descending coronary artery ligation to investigate the protective effects of E2 on myocardial I/R injury, with a particular focus on its inhibitory effects on ferroptosis and PHLDA3 in both hypoxia-reoxygenation (H/R) and I/R models. A bioinformatics analysis was conducted to evaluate the impact of estrogen receptor GPER knockout on PHLDA3 expression and ferroptosis. Loss-of-function approaches were employed to elucidate the role of PHLDA3 in ferroptosis during myocardial I/R injury. Our findings demonstrate that E2 can ameliorate myocardial I/R injury, primarily by inhibiting ferroptosis. Notably, PHLDA3 expression levels were significantly elevated during ischemia-reperfusion events; however, E2 was observed to suppress this expression. Bioinformatics analysis indicated that PHLDA3 levels increased following GPER knockdown, and the inhibitory effect of E2 on PHLDA3 expression could be partially reversed by GPER inhibitors (G15) in animal models. Furthermore, the suppression of PHLDA3 reduced ferroptosis and mitigated the severity of myocardial I/R injury. Utilizing mass spectrometry and co-immunoprecipitation methodologies, we have elucidated a potential mechanism in which PHLDA3 directly binds to and interacts with proteins involved in the process of ferroptosis.

Our findings demonstrate that E2 effectively suppresses ferroptosis and mitigates myocardial I/R injury by downregulating PHLDA3 expression through the activation of the GPER receptor.