Interleukin-1 alpha stimulated prostacyclin release by increasing gene transcription of prostaglandin H synthase and phospholipase A(2) in human vascular endothelial cells

This study was conducted to evaluate the effects of interleukin-1 alpha (IL -1 alpha) on prostacyclin (PGI(2)) production in cultured human vascular en dothelial cells in association with intracellular Ca2+, inositol 1,4,5-tris phosphate (IP3), and with prostaglandin H synthase (PGHS) and phospholipase A(2) (PLA(2)) gene expression by using the competitive polymerase chain re action (PCR) method. IL-1 alpha did not increase PGI(2) production for 15 m in, but induced an increase of about threefold relative to that in controls at 60 and 180 min. IL-1 alpha had no effect on intracellular Ca2+ levels t hroughout the experimental period. In this study, consistent with previous reports, PGHS-1 messenger RNA (mRNA) was constitutively expressed, whereas PLA, mRNA was not. After stimulation with IL-1 alpha, PLA(2) mRNA level sho wed an eightfold increase within 15 min, and PGHS-2 mRNA level increased by 76-fold within 180 min. PGHS-1 mRNA level was increased 1.6-fold at 180 mi n. These results suggest the existence of regulatory mechanisms of IL-1 alp ha-induced PGI(2) production, which involve PGHS and PLA(2) gene transcript ion.