Cardiac ischemic preconditioning promotes cMyBP-C phosphorylation by inhibiting the calpain-mediated proteolysis

Exp Cell Res. 2023 Dec 15;433(2):113859. doi: 10.1016/j.yexcr.2023.113859. Epub 2023 Nov 22.

Abstract

Ischemic preconditioning (IPC) has been considered as the most important mean to protect against ischemia/reperfusion (I/R) induced heart injury. It has been reported that cardiac myosin binding protein-C (cMyBP-C) phosphorylation plays an essential role in cardiac protection against I/R-induced heart injury. However, it is still obscured whether IPC-mediated cardiac protection is causally related to cMyBP-C phosphorylation and proteolysis and, if so, what the underlying mechanism is. In this study, IPC was found to increase the phosphorylation level of cMyBP-C, companying with the decreased calpain activity in the collected perfusate samples. Mechanistically, we confirmed that IPC promoted cMyBP-C phosphorylation and inhibited calpain-mediated cMyBP-C proteolysis. Moreover, inhibition of calpain activity significantly increased the phosphorylated cMyBP-C level by using calpain inhibitor (MG-101), and subsequently promoted stabilization and secretion of cMyBP-C. Functionally, adeno-associated virus (AAV)-mediated overexpression of mutated phosphorylation motif site of cMyBP-C exhibited impaired IPC-mediated cardiac protection via proteolysis of the full-length cMyBP-C protein. We concluded that IPC promoted cMyBP-C phosphorylation via inhibition of calpain-mediated proteolysis and participated in IPC-mediated protection against I/R induced heart injury.

Keywords: Calpain; Cardiac myosin binding protein-C; Ischemia/reperfusion; Ischemic preconditioning; Phosphorylation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calpain / metabolism
  • Heart Injuries*
  • Humans
  • Ischemic Preconditioning*
  • Phosphorylation
  • Proteolysis
  • Reperfusion Injury* / prevention & control

Substances

  • Calpain