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Original ArticleOpen Access
Initial Response of Endothelial Cells to Acute Stimulation with a Lipid Component: Increase Cyclooxygenase Activity by Induction of COX-2 through Activation of Tyrosine Kinase
Plasen D 
,
Akarasereenont P ,
Techatraisak K ,
Chotewuttakorn S ,
Thaworn A
,
Akarasereenont P ,
Techatraisak K ,
Chotewuttakorn S ,
Thaworn A Objective: To study the initial response of endothelial cells acutely stimulated with a lipid component in theaspect of cyclooxygenase (COX) function which needed for prostacyclin synthesis, an endogenous antiatherogenicagent secreted from endothelial cells.
Material and Method: 25 hydroxycholesterol (25OHC) was used as a representative lipid component forstimulating human umbilical vein endothelial cell (HUVEC) obtained from umbilical cords of healthy newbornswith informed consent of their mothers. HUVEC were treated with 25OHC (0.1, 1 or 10 microgram/mL) at times6, or 24 h. COX activity was measured from amount of 6-keto-PGF1alfa production in the presence of exogenousarachidonic acids (10 micromolar; 10 min) by enzyme immunoassay. The amount of COX-1 and COX-2 proteinwere detected by Western blot. Cell viability was assessed by using MTT assay.
Results: 25OHC induced COX-2 protein production with increasing the activity of COX enzyme in HUVECwithout change in amount of COX-1 protein. The induction of COX-2 or increasing in COX activity dependedon concentration of 25OHC and time to exposure which seemed to be inhibited by genistein, a specific tyrosinekinase inhibitor.
Conclusion: Acute stimulation of HUVEC with 25OHC, an atherosclerotic lipid component, increases theactivity of COX by inducing COX-2 expression in a manner that depended on concentration and time. Theinduction of COX-2 expression might possibly mediated through activation protein tyrosine kinase. Theseresponses may be an initial defensive mechanism of endothelial cells from lipid component attack.
Keywords: Cyclooxygenase 2, COX-2, Lipids, Oxidized LDL, 25-hydroxycholesterol, Human umbilical veinendothelial cell, HUVEC, Atherosclerosis, Tyrosine kinase
Material and Method: 25 hydroxycholesterol (25OHC) was used as a representative lipid component forstimulating human umbilical vein endothelial cell (HUVEC) obtained from umbilical cords of healthy newbornswith informed consent of their mothers. HUVEC were treated with 25OHC (0.1, 1 or 10 microgram/mL) at times6, or 24 h. COX activity was measured from amount of 6-keto-PGF1alfa production in the presence of exogenousarachidonic acids (10 micromolar; 10 min) by enzyme immunoassay. The amount of COX-1 and COX-2 proteinwere detected by Western blot. Cell viability was assessed by using MTT assay.
Results: 25OHC induced COX-2 protein production with increasing the activity of COX enzyme in HUVECwithout change in amount of COX-1 protein. The induction of COX-2 or increasing in COX activity dependedon concentration of 25OHC and time to exposure which seemed to be inhibited by genistein, a specific tyrosinekinase inhibitor.
Conclusion: Acute stimulation of HUVEC with 25OHC, an atherosclerotic lipid component, increases theactivity of COX by inducing COX-2 expression in a manner that depended on concentration and time. Theinduction of COX-2 expression might possibly mediated through activation protein tyrosine kinase. Theseresponses may be an initial defensive mechanism of endothelial cells from lipid component attack.
Keywords: Cyclooxygenase 2, COX-2, Lipids, Oxidized LDL, 25-hydroxycholesterol, Human umbilical veinendothelial cell, HUVEC, Atherosclerosis, Tyrosine kinase
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