Post-conditioning protects rat cardiomyocytes via PKCepsilon-mediated calcium-sensing receptors.
Protein kinase C (PKC) plays a role in cardioprotection through reduction of intracellular Ca(2+) concentration [Ca(2+)](i) during ischemic preconditioning (IPC). Cardioprotection against ischemic post-conditioning (PC) could be associated with reduced [Ca(2+)](i) through PKC. The calcium-sensing receptor (CaR), G protein-coupled receptor, causes accumulation of inositol phosphate (IP) to increase the release of intracellular Ca(2+). However, this phenomenon can be negatively regulated by PKC through phosphorylation of Thr-888 of the CaR. This study tested the hypothesis that the prevention of cardiomyocyte damage by PC is associated with [Ca(2+)](i) reduction through an interaction of PKC with the CaR. Isolated rat hearts were subjected to 40min of ischemia followed by 90min of reperfusion. The hearts were post-conditioned after the 40min of ischemia by three cycles of 30s of reperfusion and 30s of re-ischemia applied before the 90min of reperfusion. Immunolocalization of PKCepsilon in the cell membrane was observed with IPC and PC, and in hearts exposed to GdCl(3) during PC. CaR was expressed in cardiac cell membrane and interacted with PKC in IPC, PC, and exposure to GdCl(3) during PC groups. On laser confocal microscopy, intracellular Ca(2+) was significantly decreased with IPC, PC, and exposure to GdCl(3) during PC compared with the I/R and PKC inhibitor groups, and cell structure was better preserved and promoted the recovery of cardiac function after reperfusion in the same groups. These results suggested that PKC is involved in cardioprotection against PC through negative feedback of a CaR-mediated reduction in [Ca(2+)](i).
Zhang
Wei-Hua
WH
Department of Pathophysiology, Harbin Medical University, Harbin 150086, China.
Lu
Fang-Hao
FH
Zhao
Ya-Jun
YJ
Wang
Li-Na
LN
Tian
Ye
Y
Pan
Zhen-Wei
ZW
Lv
Yan-Jie
YJ
Wang
Yan-Li
YL
Du
Li-Juan
LJ
Sun
Zhi-Rui
ZR
Yang
Bao-Feng
BF
Wang
Rui
R
Xu
Chang-Qing
CQ
D000818:Animals; D002118:Calcium / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D015428:Myocardial Reperfusion Injury / Q000201:enzymology / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000201:enzymology / Q000378:metabolism* / Q000648:ultrastructure; D010766:Phosphorylation; D051744:Protein Kinase C-epsilon / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D044169:Receptors, Calcium-Sensing / Q000378:metabolism*; D013912:Threonine / Q000235:genetics / Q000378:metabolism
D044169:Receptors, Calcium-Sensing; D013912:Threonine; D051744:Protein Kinase C-epsilon; D002118:Calcium