6-ketoprostaglandin-f1-alpha and 25-hydroxycholesterol

To study the initial response of endothelial cells acutely stimulated with a lipid component in the aspect of cyclooxygenase (COX) function which needed for prostacyclin synthesis, an endogenous antiatherogenic agent secreted from endothelial cells.. 25 hydroxycholesterol (25OHC) was used as a representative lipid component for stimulating human umbilical vein endothelial cell (HUVEC) obtained from umbilical cords of healthy newborns with informed consent of their mothers. HUVEC were treated with 25OHC (0.1, 1 or 10 microgram/mL) at times 6, or 24 h. COX activity was measured from amount of 6-keto-PGF(1 alfa) production in the presence of exogenous arachidonic acids (10 micromolar; 10 min) by enzyme immunoassay. The amount of COX-1 and COX-2 protein were detected by Western blot. Cell viability was assessed by using MTT assay.. 25OHC induced COX-2 protein production with increasing the activity of COX enzyme in HUVEC without change in amount of COX-1 protein. The induction of COX-2 or increasing in COX activity depended on concentration of 25OHC and time to exposure which seemed to be inhibited by genistein, a specific tyrosine kinase inhibitor.. Acute stimulation of HUVEC with 25OHC, an atherosclerotic lipid component, increases the activity of COX by inducing COX-2 expression in a manner that depended on concentration and time. The induction of COX-2 expression might possibly mediated through activation protein tyrosine kinase. These responses may be an initial defensive mechanism of endothelial cells from lipid component attack.

Topics: 6-Ketoprostaglandin F1 alpha; Antihypertensive Agents; Arachidonic Acids; Blotting, Western; Cyclooxygenase 2; Dose-Response Relationship, Drug; Endothelial Cells; Endothelium, Vascular; Epoprostenol; Genistein; Humans; Hydroxycholesterols; Immunoenzyme Techniques; Infant, Newborn; Prostaglandin-Endoperoxide Synthases; Protein Kinase Inhibitors; Protein-Tyrosine Kinases; Time Factors; Umbilical Veins