Activation of calcium-sensing receptors is associated with apoptosis in a model of simulated cardiomyocytes ischemia/reperfusion

Ling Yan,Tiebing Zhu,Tingting Sun,Liansheng Wang,Shiyang Pan,Zhengxian Tao,Zhijian Yang,Kejiang Cao

doi:10.1016/s1674-8301(10)60042-5

Abstract

Objective Calcium-sensing receptors (CaSRs) are G-protein coupled receptors which maintain systemic calcium homeostasis and participate in hormone secretion, activation of ion channels, cell apoptosis, proliferation, and differentiation. Previous studies have shown that CaSRs induce apoptosis in isolated adult rat heart and in normal neonatal rat cardiomyocytes by G-protein-PLC-IP 3 signaling transduction. However, little knowledge is presently available concerning the role of CaSRs in the apoptosis induced by ischemia and reperfusion in neonatal cardiomyocytes. Methods Primary neonatal rat ventricular cardiomyocytes were incubated in ischemiamimetic solution for 2 h, and then re-incubated in normal culture medium for 24 h to establish a model of simulated ischemia/reperfusion (I/R). Cardiomyocyte apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). The expression of CaSRs mRNA was detected by real-time reverse transcription polymerase chain reaction (RT-PCR). In addition, the expressions of caspase-3 and Bcl-2 were analyzed by western blot. Results The simulated I/R enhanced the expression of CaSRs and cardiomyocyte apoptosis. GdCl 3, a specific activator of CaSRs, further increased the expression of CaSRs and cardiomyocyte apoptosis, along with up-regulation of caspase-3 and down-regulation of Bcl-2. Conclusion CaSRs are associated with I/R injury and apoptosis in neonatal rat ventricular cardiomyocytes via suppressing Bcl-2 and promoting caspase-3 expression.

Highlights

The calcium-sensing receptor (CaSR) belongs to family C II of the superfamily of seven-transmembrane (7TM) receptors, termed G protein-coupledIt has three structural domains: 1 an unusually large extracellular domain, characteristic of the family CSmall increases in extracelluar Ca2+ concentrationL.Yan et al / Journal of Biomedical Research, 2010, 24(4): 301-307 can cause the synthesis of nitric oxide (NO) by vascular endothelium, resulting in vessel dilation[7]
Previous studies have shown that CaSR was expressed in rat neonatal and adult ventricular cardiomyocytes
Our results revealed that apoptosis induced by simulated I/R was increased as the CaSR mRNA expression, and GdCl3, a specific activator of CaSR, further enhanced both the apoptosis and the CaSR mRNA expression

Summary

Introduction

The calcium-sensing receptor (CaSR) belongs to family C II of the superfamily of seven-transmembrane (7TM) receptors, termed G protein-coupledIt has three structural domains: 1 an unusually large extracellular domain, characteristic of the family CSmall increases in extracelluar Ca2+ concentrationL.Yan et al / Journal of Biomedical Research, 2010, 24(4): 301-307 can cause the synthesis of nitric oxide (NO) by vascular endothelium, resulting in vessel dilation[7]. The calcium-sensing receptor (CaSR) belongs to family C II of the superfamily of seven-transmembrane (7TM) receptors, termed G protein-coupled. It has three structural domains: 1 an unusually large extracellular domain, characteristic of the family C. Downstream of or in parallel with PLC, the CaSR activates mitogen-activated protein kinases (MAPKs) and phosphatidylinositol-4-kinase (PI4K). It activates the PKC, ERK1/2, p38 MAPK and JNK pathways which are known to play an important role in extracelluar signaling transmission from the cell surface to nucleus and in cell cycle regulation[10]

Methods

Results

Conclusion