TY - JOUR
T1 - Ablation of the calpain-targeted site in cardiac myosin binding protein-C is cardioprotective during ischemia-reperfusion injury
AU - Barefield, David Y.
AU - McNamara, James W.
AU - Lynch, Thomas L.
AU - Kuster, Diederik W. D.
AU - Govindan, Suresh
AU - Haar, Lauren
AU - Wang, Yang
AU - Taylor, Erik N.
AU - Lorenz, John N.
AU - Nieman, Michelle L.
AU - Zhu, Guangshuo
AU - Luther, Pradeep K.
AU - Varró, Andras
AU - Dobrev, Dobromir
AU - Ai, Xun
AU - Janssen, Paul M. L.
AU - Kass, David A.
AU - Jones, Walter Keith
AU - Gilbert, Richard J.
AU - Sadayappan, Sakthivel
PY - 2019/4/1
Y1 - 2019/4/1
N2 - Cardiac myosin binding protein-C (cMyBP-C) phosphorylation is essential for normal heart function and protects the heart from ischemia-reperfusion (I/R) injury. It is known that protein kinase-A (PKA)-mediated phosphorylation of cMyBP-C prevents I/R-dependent proteolysis, whereas dephosphorylation of cMyBP-C at PKA sites correlates with its degradation. While sites on cMyBP-C associated with phosphorylation and proteolysis co-localize, the mechanisms that link cMyBP-C phosphorylation and proteolysis during cardioprotection are not well understood. Therefore, we aimed to determine if abrogation of cMyBP-C proteolysis in association with calpain, a calcium-activated protease, confers cardioprotection during I/R injury. Calpain is activated in both human ischemic heart samples and ischemic mouse myocardium where cMyBP-C is dephosphorylated and undergoes proteolysis. Moreover, cMyBP-C is a substrate for calpain proteolysis and cleaved by calpain at residues 272-TSLAGAGRR-280, a domain termed as the calpain-target site (CTS). Cardiac-specific transgenic (Tg) mice in which the CTS motif was ablated were bred into a cMyBP-C null background. These Tg mice were conclusively shown to possess a normal basal structure and function by analysis of histology, electron microscopy, immunofluorescence microscopy, Q-space MRI of tissue architecture, echocardiography, and hemodynamics. However, the genetic ablation of the CTS motif conferred resistance to calpain-mediated proteolysis of cMyBP-C. Following I/R injury, the loss of the CTS reduced infarct size compared to non-transgenic controls. Collectively, these findings demonstrate the physiological significance of calpain-targeted cMyBP-C proteolysis and provide a rationale for studying inhibition of calpain-mediated proteolysis of cMyBP-C as a therapeutic target for cardioprotection.
AB - Cardiac myosin binding protein-C (cMyBP-C) phosphorylation is essential for normal heart function and protects the heart from ischemia-reperfusion (I/R) injury. It is known that protein kinase-A (PKA)-mediated phosphorylation of cMyBP-C prevents I/R-dependent proteolysis, whereas dephosphorylation of cMyBP-C at PKA sites correlates with its degradation. While sites on cMyBP-C associated with phosphorylation and proteolysis co-localize, the mechanisms that link cMyBP-C phosphorylation and proteolysis during cardioprotection are not well understood. Therefore, we aimed to determine if abrogation of cMyBP-C proteolysis in association with calpain, a calcium-activated protease, confers cardioprotection during I/R injury. Calpain is activated in both human ischemic heart samples and ischemic mouse myocardium where cMyBP-C is dephosphorylated and undergoes proteolysis. Moreover, cMyBP-C is a substrate for calpain proteolysis and cleaved by calpain at residues 272-TSLAGAGRR-280, a domain termed as the calpain-target site (CTS). Cardiac-specific transgenic (Tg) mice in which the CTS motif was ablated were bred into a cMyBP-C null background. These Tg mice were conclusively shown to possess a normal basal structure and function by analysis of histology, electron microscopy, immunofluorescence microscopy, Q-space MRI of tissue architecture, echocardiography, and hemodynamics. However, the genetic ablation of the CTS motif conferred resistance to calpain-mediated proteolysis of cMyBP-C. Following I/R injury, the loss of the CTS reduced infarct size compared to non-transgenic controls. Collectively, these findings demonstrate the physiological significance of calpain-targeted cMyBP-C proteolysis and provide a rationale for studying inhibition of calpain-mediated proteolysis of cMyBP-C as a therapeutic target for cardioprotection.
KW - Calpain
KW - Cardioprotection
KW - Ischemia-reperfusion injury
KW - MYBPC3
KW - cMyBP-C
UR - https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85063037205&origin=inward
UR - https://www.ncbi.nlm.nih.gov/pubmed/30862451
U2 - https://doi.org/10.1016/j.yjmcc.2019.03.006
DO - https://doi.org/10.1016/j.yjmcc.2019.03.006
M3 - Article
C2 - 30862451
SN - 0022-2828
VL - 129
SP - 236
EP - 246
JO - Journal of molecular and cellular cardiology
JF - Journal of molecular and cellular cardiology
ER -