Inhibitory effects of eicosapentaenoic acid (EPA) on the hypoxia/reoxygenation-induced tyrosine kinase activation in cultured human umbilical vein endothelial cells.
We have previously reported that the n-3 polyunsaturated fatty acid eicosapentaenoic acid (EPA) inhibited the abnormal gap junctional intercellular communication (GJIC) induced by hypoxia/reoxygenation (H/R) via suppressing tyrosine kinase (TK) activation (Zhang et al., Prostaglandins Leukot Essent Fatty Acids, 1999; 61: 33-40). However, the mechanisms by which EPA-inhibited TK activation remained unidentified. In this study we investigated whether reactive oxygen species (ROS) and growth factor-receptor systems would contribute to the H/R-induced TK activation or not. The results showed that H/R-induced ROS production, which reached the peak after 30 min of reoxygenation. Pretreatment with 10 microM EPA significantly inhibited this ROS production. However, the TK inhibitor genistein (10 microM) failed to inhibit the generation of ROS, although it completely inhibited TK activation. On the other hand, the ROS inhibitor DMSO (0.5% v/v) showed little effect on TK activation while it significantly blocked ROS production. Further EPA and genistein, but not DMSO and superoxide dismutase (SOD, 300 U/ml), prevented cells from GJIC injury induced by H/R. Moreover, EPA protected against VEGF-induced reduction in GJIC and phosphorylation of connexin 43. These data suggest that growth factor, but not ROS, might be involved in the EPA-inhibited TK activation induced by H/R.
Zhang
Y W
YW
Section of Cellular Physiological Chemistry, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
Yao
X S
XS
Murota
S
S
Morita
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I
D002450:Cell Communication / Q000187:drug effects; D018929:Cell Culture Techniques; D018031:Connexin 43 / Q000378:metabolism; D015118:Eicosapentaenoic Acid / Q000494:pharmacology*; D016228:Endothelial Growth Factors / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D004789:Enzyme Activation / Q000187:drug effects; D036681:Fluorescence Recovery After Photobleaching; D017629:Gap Junctions / Q000187:drug effects; D006801:Humans; D000860:Hypoxia / Q000378:metabolism*; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology; D008222:Lymphokines / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors*; D017382:Reactive Oxygen Species / Q000378:metabolism; D014471:Umbilical Veins; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D018031:Connexin 43; D016228:Endothelial Growth Factors; D036341:Intercellular Signaling Peptides and Proteins; D008222:Lymphokines; D017382:Reactive Oxygen Species; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D015118:Eicosapentaenoic Acid; D011505:Protein-Tyrosine Kinases