EICOSANOID PROFILE IN CULTURED HUMAN PULMONARY-ARTERY SMOOTH-MUSCLE CELLS TREATED WITH IL-1-BETA AND TNF-ALPHA

Interleukin-1 beta (IL-1 beta) and tumor necrosis factor (TNF alpha) i nduce prostanoid biosynthesis in vascular smooth muscle cells by promo ting cyclooxygenase (COX) expression, but little is known about the bi osynthesis of lipoxygenase (LPO) metabolites. We investigated the effe cts of human recombinant IL-1 beta and TNF alpha on the production of arachidonic acid (AA) metabolites by high-performance liquid chromatog raphy (HPLC). After being labelled with H-3-AA, cultured human pulmona ry artery smooth muscle cells (HPASMC) were incubated with or without IL-IP (200 U /ml) and TNF alpha (500 U/ml). The arachidonic acid metab olites released from HPASMC were then analysed by HPLC. In control HPA SMC, 6-keto-PGF(1 alpha) and PGE(2) were the principal metabolites of the COX pathway, while 5-HETE, LTC4 and D-4 were the main products of the LPO pathway. HPASMC treated with 200 U/ml of IL-1 beta and 500 U/m l of TNF alpha produced more COX metabolites such as 6-keto-PGF(1 alph a) thromboxane B2, PGF(2 alpha) and PGE(2) than control cells. Signifi cant increases in the production of LPO derivatives such as LTB4, C-4, D-4, and 15-HETE were also found in IL-lp-treated HPASMC. Although th e release of LPO products tended to increase in TNF alpha-treated cell s, no significant change was noted. Many AA metabolites including LTB4 are responsible for the inflammatory process in vivo. AA metabolites produced by pulmonary artery smooth muscle cells might play important roles in cytokine-mediated acute lung injury and inflammation.