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Human umbilical vein endothelial cells (HUVECs) show Ca 2+ mobilization as well as Ca 2+ influx upon hypoxia
Author(s) -
Aono Yasuhisa,
Ariyoshi Hideo,
Sakon Masato,
Ueda Atsushi,
Tsuji Yoshihisa,
Kawasaki Tomio,
Monden Morito
Publication year - 2000
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/1097-4644(20000901)78:3<458::aid-jcb10>3.0.co;2-f
Subject(s) - bleb (medicine) , extracellular , umbilical vein , hypoxia (environmental) , egta , chemistry , cytoplasm , intracellular , biophysics , microbiology and biotechnology , calcium , biology , biochemistry , in vitro , trabeculectomy , oxygen , organic chemistry , neuroscience , glaucoma
Bleb formation is an early event of cellular damage observed in a variety of cell types upon hypoxia. Although we previously found that the [Ca 2+ ] i rise before bleb formation only at the same loci of HUVECs upon hypoxia (localized [Ca 2+ ] i rise), the mode of the [Ca 2+ ] i rise remains ill‐defined. In order to clarify the mechanisms causing the localized [Ca 2+ ] i rise in hypoxia challenged HUVECs, we studied the effects of several Ca 2+ channel blockers or a Ca 2+ chelator, EGTA, which reduces extracellular Ca 2+ concentration on the hypoxia‐induced localized [Ca 2+ ] i rise and bleb formation by employing a confocal laser scanning microscopy (CLSM). After the initiation of hypoxia, [Ca 2+ ] i rose gradually in a localized fashion up to 15 min, which was associated with bleb formation at the same loci. The maximal [Ca 2+ ] i rise was 435 ± 84 nM at the loci of bleb formation. Ca 2+ channel blockers including Ni 2+ (non‐specific, 1 mM), nifedipine (L type, 10 μM), nicardipine (L + T type, 10 μM), and cilnidipine (L + N type, 10 μM) did not inhibit either the localized [Ca 2+ ] i rise or bleb formation. Although both the localized [Ca 2+ ] i rise and bleb formation were inhibited by lowering extracellular Ca 2+ concentration below 100 nM, a diffuse [Ca 2+ ] i rise through the cytoplasm remained without bleb formation, which was inhibited by a phospholipase C (PLC) inhibitor, U73122. In conclusion, hypoxia causes both the Ca 2+ mobilization and the Ca 2+ influx in HUVECs and the Ca 2+ influx through unknown Ca 2+ channels is responsible for the localized [Ca 2+ ] i rise integral to bleb formation. J. Cell. Biochem. 78:458–464, 2000. © 2000 Wiley‐Liss, Inc.