AUTHOR=Wang Qiang , Park Ki Ho , Geng Bingchuan , Chen Peng , Yang Chunlin , Jiang Qiwei , Yi Frank , Tan Tao , Zhou Xinyu , Bian Zehua , Ma Jianjie , Zhu Hua 

TITLE=MG53 Inhibits Necroptosis Through Ubiquitination-Dependent RIPK1 Degradation for Cardiac Protection Following Ischemia/Reperfusion Injury

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2022.868632

DOI=10.3389/fcvm.2022.868632

ISSN=2297-055X

ABSTRACT=Aims: While reactive oxygen species (ROS) has been recognized as one of main causes of cardiac injury following myocardial infarction, the clinical application of antioxidants have shown limited effects on protecting hearts against ischemia/reperfusion (I/R) injury. Thus, the precise role of ROS following cardiac injury remains to be fully elucidated. We investigated the role of mitsugumin 53 (MG53) on regulating necroptosis following I/R injury to the hearts and involvement of ROS in MG53 mediated cardioprotection.
Results: Antioxidant was used to test the role of ROS in MG53 mediated cardioprotection in mouse model of I/R injury. Western blotting and co-immunoprecipitation were used to identify potential cell death pathways that MG53 was involved in. CRISPR/Cas 9 mediated genome editing and mutagenesis assays were performed to further identify specific interaction amino acid between MG53 and its ubiquitin E3 ligase substrate. We found that MG53 could protect myocardial injury via inhibiting necroptosis pathway. Upon injury, generation of ROS in infarct zone of the hearts promoted interaction between MG53 and Receptor-interacting protein kinase 1 (RIPK1). As an E3 ubiquitin ligase, MG53 added multiple ubiquitin chain to RIPK1 at the sites of K316, K604 and K627 for proteasome mediated RIPK1 degradation and inhibited necroptosis. Application of N-acetyl cysteine (NAC) disrupted interaction between MG53 and RIPK1 and abolished MG53 mediated cardioprotective effects.
Innovation and conclusion: The current study provided a molecular mechanism of a potential beneficial role of ROS following acute myocardial infarction. Thus, fine tuning ROS level is critical for cardioprotection.