Post-infarction KLHL40-mediated regulation of cardiac sarcomeric integrity and function

Area of Science:

• Cardiovascular Biology
• Molecular Mechanisms of Cardiac Disease
• Sarcomeric Protein Regulation

Background:

• Cardiac sarcomeric remodeling is critical in post-myocardial infarction (MI) dysfunction.
• Molecular mechanisms underlying this remodeling are not fully understood.

Purpose of the Study:

• To investigate the role of Kelch-like protein 40 (KLHL40) in sarcomeric protein remodeling and calcium signaling post-MI.
• To characterize the impact of KLHL40 on cardiac cells following hypoxic injury.

Main Methods:

• Integrated transcriptomic and proteomic data with experimental validation.
• Assessed KLHL40 expression in human post-MI tissues and hypoxia-induced cells.
• Functional assays examined KLHL40's regulation of Z-disc proteins, calcium signaling, calpain activity, inflammasome activation, and apoptosis.

Main Results:

• KLHL40 expression increased significantly post-MI, reducing key sarcomeric proteins (MYOT, CAPZA, TCAP) but not ACTN2 or FLNC.
• KLHL40 modulated intracellular calcium handling, calpain activity, and decreased inflammasome components (NLRP3, Cleaved Caspase-1).
• KLHL40 influenced apoptosis pathways (BCL2/BAX ratio) and its degradation was regulated by proteasomal, autophagic, and calpain pathways.

Conclusions:

• KLHL40 preserves sarcomeric integrity and cardiomyocyte viability post-MI.
• It achieves this by modulating calpain signaling, inflammasome activation, and apoptosis.
• KLHL40 stability is controlled by proteasomal, autophagic, and calpain-dependent mechanisms.