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Endothelin‐1 (ET‐1)‐induced reactive oxygen species (ROS) generation requires calcium (Ca 2+ ) influx in pulmonary arterial smooth muscle cells (PASMCs)
Author(s) -
Undem Clark,
Luke Trevor,
Sylvester J T,
Shimoda Larissa A
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.1061.11
Subject(s) - nadph oxidase , reactive oxygen species , nicotinamide adenine dinucleotide phosphate , chemistry , bapta , extracellular , apocynin , intracellular , calcium , vascular smooth muscle , oxidase test , microbiology and biotechnology , biochemistry , endocrinology , biology , enzyme , organic chemistry , smooth muscle
ET‐1 is a potent endothelium‐derived vasoconstrictor and smooth muscle cell mitogen. During hypoxia, ET‐1 is thought to play a significant role in modulation pulmonary vascular tone. Previous studies in systemic smooth muscle have shown that both an increase in intracellular Ca 2+ concentration ([Ca 2+ ] i ) and the generation of ROS via nicotinamide adenine dinucleotide phosphate‐oxidase (NADPH oxidase) are major components of ET‐1 signaling. It remains unclear, however, whether ET‐1 causes ROS generation in PASMCs. In this study, we used the ROS‐sensitive dye, DCF, and the Ca 2+ ‐sensitive dye, fura‐2, to determine 1) the effect of ET‐1 on ROS production in transiently cultured (24–48 hr) rat PASMCs and 2) whether this response is Ca 2+ ‐dependent. Measuring both [Ca 2+ ] i and ROS simultaneously, we found that ET‐1 significantly increased both Ca 2+ influx and ROS generation, with Ca 2+ influx appearing to occur first. Pre‐treating PASMCs with the antioxidant, TEMPOL, or the NADPH oxidase inhibitor, diphenyleneiodonium chloride, had no significant effect on ET‐1‐induced Ca 2+ influx but prevented ROS production. In contrast, the removal of extracellular Ca 2+ or pretreatment with the Ca 2+ chelator, BAPTA‐AM, prevented both the increase in [Ca 2+ ] i and ROS production. These results indicate that, in PASMCs, Ca 2+ influx may be necessary for the ET‐1‐induced initiation of ROS production from NADPH oxidase. HL67191