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Multiple Ca 2+ signaling pathways regulate intracellular Ca 2+ activity in human cardiac fibroblasts
Author(s) -
Chen JingBo,
Tao Rong,
Sun HaiYing,
Tse HungFat,
Lau ChuPak,
Li GuiRong
Publication year - 2010
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.22010
Subject(s) - ryanodine receptor , phospholipase c , thapsigargin , serca , myocyte , intracellular , calcium signaling , microbiology and biotechnology , signal transduction , inositol trisphosphate receptor , inositol , endocrinology , orai1 , medicine , extracellular , biology , calcium , chemistry , endoplasmic reticulum , receptor , stim1 , biochemistry , atpase , enzyme
Ca 2+ signaling pathways are well studied in cardiac myocytes, but not in cardiac fibroblasts. The aim of the present study is to characterize Ca 2+ signaling pathways in cultured human cardiac fibroblasts using confocal scanning microscope and RT‐PCR techniques. It was found that spontaneous intracellular Ca 2+ (Ca i 2+ ) oscillations were present in about 29% of human cardiac fibroblasts, and the number of cells with Ca i 2+oscillations was increased to 57.3% by application of 3% fetal bovine serum. Ca i 2+oscillations were dependent on Ca 2+ entry. Ca i 2+oscillations were abolished by the store‐operated Ca 2+ (SOC) entry channel blocker La 3+ , the phospholipase C inhibitor U‐73122, and the inositol trisphosphate receptors (IP3Rs) inhibitor 2‐aminoethoxydiphenyl borate, but not by ryanodine. The IP3R agonist thimerosal enhanced Ca i 2+oscillations. Inhibition of plasma membrane Ca 2+ pump (PMCA) and Na + –Ca 2+ exchanger (NCX) also suppressed Ca i 2+oscillations. In addition, the frequency of Ca i 2+oscillations was reduced by nifedipine, and increased by Bay K8644 in cells with spontaneous Ca 2+ oscillations. RT‐PCR revealed that mRNAs for IP3R1‐3, SERCA1‐3, Ca V 1.2, NCX3, PMCA1,3,4, TRPC1,3,4,6, STIM1, and Orai1‐3, were readily detectable, but not RyRs. Our results demonstrate for the first time that spontaneous Ca i 2+oscillations are present in cultured human cardiac fibroblasts and are regulated by multiple Ca 2+ pathways, which are not identical to those of the well‐studied contractile cardiomyocytes. This study provides a base for future investigations into how Ca 2+ signals regulate biological activity in human cardiac fibroblasts and cardiac remodeling under pathological conditions. J. Cell. Physiol. 223: 68–75, 2010. © 2009 Wiley‐Liss, Inc.