MG53 Inhibits Necroptosis Through Ubiquitination-Dependent RIPK1 Degradation for Cardiac Protection Following...

Area of Science:

• Cardiovascular Biology
• Molecular Cardiology
• Cell Death Pathways

Background:

• Reactive oxygen species (ROS) are implicated in cardiac injury post-myocardial infarction, but their precise role is unclear.
• Clinical use of antioxidants has shown limited efficacy in protecting hearts from ischemia-reperfusion (I/R) injury.
• Understanding the dual role of ROS in cardiac injury is critical for developing effective treatments.

Purpose of the Study:

• To investigate the role of mitsugumin 53 (MG53) in regulating necroptosis following cardiac I/R injury.
• To elucidate the involvement of ROS in MG53-mediated cardioprotection.
• To identify the molecular mechanisms underlying MG53's protective effects.

Main Methods:

• Utilized a mouse model of I/R injury and human pluripotent stem cell-derived cardiomyocytes subjected to hypoxia/re-oxygenation (H/R) injury.
• Employed antioxidants to assess ROS involvement in MG53-mediated cardioprotection.
• Applied Western blotting, co-immunoprecipitation, CRISPR/Cas9 genome editing, and mutagenesis assays to identify molecular interactions and pathways.

Main Results:

• MG53 protects against myocardial injury by inhibiting the necroptosis pathway.
• ROS generation promotes the interaction between MG53 and receptor-interacting protein kinase 1 (RIPK1) in the infarct zone.
• MG53, acting as an E3 ubiquitin ligase, targets RIPK1 for proteasomal degradation, thereby inhibiting necroptosis.
• N-acetyl cysteine (NAC) disrupted MG53-RIPK1 interaction and abolished MG53's cardioprotective effects.

Conclusions:

• This study reveals a novel molecular mechanism for the beneficial role of ROS in acute myocardial infarction.
• MG53-mediated inhibition of RIPK1-dependent necroptosis is a key cardioprotective pathway.
• Fine-tuning ROS levels, rather than complete elimination, may be critical for achieving cardioprotection post-myocardial infarction.