title: Pretreatment with eicosapentaenoic acid prevented hypoxia/reoxygenation-induced abnormality in endothelial gap junctional intercellular communication through inhibiting the tyrosine kinase activity.
abstract: Eicosapentaenoic acid (EPA) may protect against atherosclerotic disease, and modulation of endothelium function is one possible mechanism. Hypoxia/reoxygenation (H/R) is a potential risk factor for the pathogenesis of atherosclerosis, and it causes endothelial dysfunction. To evaluate whether EPA may improve the endothelial dysfunction under the condition of H/R, we examined endothelial gap junctional intercellular communication (GJIC), which is said to be important for the endothelium to maintain its normal function. The results indicate that H/R induced a temporal reduction in GJIC after 2 h of reoxygenation in cultured human umbilical vein endothelial cells (HUVEC). This reduction in GJIC was not observed in cells pretreated with 3 microg/ml EPA for 2 days. The results of immunofluorescence show that 2 h reoxygenation caused an increased production of tyrosine-phosphorylated proteins, which was inhibited by EPA pretreatment. Immunoprecipitation demonstrated that tyrosine residues of connexin 43 (Cx43), an important gap junctional protein in HUVEC, were phosphorylated by H/R. However, pretreatment with EPA significantly suppressed this increased phosphorylation. The protective effect of EPA on the reduction in GJIC was also observed in cells treated with 1.5 mM vanadate, a tyrosine phosphatase inhibitor. These data suggest that EPA may ameliorate the H/R-induced GJIC abnormality via inhibition of the tyrosine kinase activation.
authors.affiliation: Department of Physiological Chemistry, Graduate School, Tokyo Medical and Dental University, Japan.
authors.forename: Y W
authors.initials: YW
authors.lastname: Zhang
authors.forename: I
authors.initials: I
authors.lastname: Morita
authors.forename: X S
authors.initials: XS
authors.lastname: Yao
authors.forename: S
authors.initials: S
authors.lastname: Murota
mesh_terms: D015687:Cell Hypoxia / Q000187:drug effects*; D002478:Cells, Cultured; D018031:Connexin 43 / Q000378:metabolism; D015118:Eicosapentaenoic Acid / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000648:ultrastructure*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D017629:Gap Junctions / Q000187:drug effects*; D006801:Humans; D007163:Immunosorbent Techniques; D007700:Kinetics; D010100:Oxygen / Q000008:administration & dosage*; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors*; D014471:Umbilical Veins
chemical_list: D018031:Connexin 43; D004791:Enzyme Inhibitors; D019000:Phosphotyrosine; D015118:Eicosapentaenoic Acid; D011505:Protein-Tyrosine Kinases; D010100:Oxygen