Calcium-sensing receptors induce apoptosis in cultured neonatal rat ventricular cardiomyocytes during simulated ischemia/reperfusion

Authors

  • Chun-ming Jiang,

    1. Department of Pathophysiology, Harbin Medical University, Baojian Street, Harbin 150086, China
    2. Department of Neonatology, The First Clinical Hospital of Harbin Medical University, Harbin 150001, China
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    • Tel.: +86 451 53601657; fax: +86 451 82392885.

  • Li-Ping Han,

    1. Department of Pathophysiology, Harbin Medical University, Baojian Street, Harbin 150086, China
    2. Department of Physiology, Wenzhou Medical College, Wenzhou 325035, China
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  • Hong-Zhu Li,

    1. Department of Pathophysiology, Harbin Medical University, Baojian Street, Harbin 150086, China
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  • Ying-Bo Qu,

    1. Department of Neonatology, The First Clinical Hospital of Harbin Medical University, Harbin 150001, China
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  • Zhuo-Ran Zhang,

    1. Department of Pathophysiology, Harbin Medical University, Baojian Street, Harbin 150086, China
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  • Rui Wang,

    1. Department of Pathophysiology, Harbin Medical University, Baojian Street, Harbin 150086, China
    2. Department of Biology, Lakehead University, Thunder Bay, Onario, Canada P7B 5E1
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  • Chang-qing Xu,

    Corresponding author
    1. Department of Pathophysiology, Harbin Medical University, Baojian Street, Harbin 150086, China
    2. Bio-pharmaceutical Key Laboratory of Heilongjiang Province, Harbin 150086, China
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  • Wei-ming Li

    Corresponding author
    1. Department of Cardiovascular, The First Clinical Hospital of Harbin Medical University, Harbin 150001, China
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Corresponding author. Department of Pathophysiology, Harbin Medical University, Baojian Street, Harbin 150086, China. Tel.: +86 451 86674548; fax: +86 451 87503325. jiangchunming1975@163.com xucq45@126.com

Corresponding author.

Abstract

Calcium-sensing receptors (CaSRs) are G-protein coupled receptors which regulate systemic calcium homeostasis and also participate in cell proliferation, differentiation and apoptosis. We have previously shown that CaSR can induce apoptosis in isolated rat adult hearts and in normal rat neonatal cardiomyocytes. However, no knowledge exists concerning the role of CaSR in apoptosis induced by ischemia and reperfusion in neonatal cardiac myocytes. Therefore, in the present study, we incubated primary neonatal rat ventricular cardiomyocytes in ischemia-mimetic solution for 2 h, then re-incubated them in a normal culture medium for 24 h to establish a model of simulated ischemia/reperfusion (I/R). We assayed the apoptotic ratio of the cardiomyocytes by flow cytometry; observed morphological alterations by transmission electron microscope; analyzed the expression of caspase-3, Bcl-2, CaSR, extracellular signal-regulated protein kinase (ERK), and Fas/Fas ligand (FasL) by Western blotting; and measured the concentration of intracellular calcium by Laser Confocal Scanning Microscopy. The results showed that simulated I/R increased the expression of CaSR and cardiomyocyte apoptosis. GdCl3, a specific activator of CaSR, further enhanced CaSR expression, along with increases in intracellular calcium and apoptosis in cardiomyocytes during I/R. Activation of CaSR down-regulated Bcl-2 expression, up-regulated caspase-3 and Fas/FasL expression and stimulated ERK1/2 phosphorylation. In summary, CaSR is involved in I/R injury and apoptosis of neonatal rat ventricular cardiomyocytes by inhibiting Bcl-2, inducing calcium overload and activating the Fas/FasL death receptor pathway.

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