The Mediating Roles Of CPLA₂ To IL-1β And IL-6 In LPS Induced HeLa Cells

LPS has been strongly linked to the pathophysiological responses that result in septic shock. A number of signaling pathways that are initiated by LPS lead to the production of cytokines, which in the end result in the septic shock. It has recently become evident that p38 MAPK play a crucial role in that process. However, the precise mechanism by which p38 regulates cytokines releases is still uncertain. It should be noticed that cPLA2, as an important isform of PLA2, is the substrate of p3 8 and phosphorylated during LPS induced inflammation. We have previously described that the nonspecific inhibitors of PLA2 could reduce the generation of IL-1β in certain organs of rat ischemia-reperfusion injury model. It indicated the possible relationship between PL A2 and IL-1β production during inflammation.To explore further the effect of cPLA2 on cytokines releases in inflammatory process, a HeLa cell model was characterized. cPLA2 activity and expression were designed to be separately inhibited byAACOCF3, a potential and specific inhibitor of cPLA2, and cPLA2 antisense oligonucleotide. At the same time, the changes of IL-1 β, IL-6 levels in the supernatants of all samples were detected. Detailed approaches are as followed:1. First, p38 specific inhibitor SB203580 was added to the culture, followed by LPS treatment. Then, the IL-1 β, IL-6 releases of each group were assayed. The results showed that SB203580 decreased the cytokines production. Next, AACOCF3 was used to reduce the activity of cPLA2, and dose dependently inhibitions of AACOCF3 were noticed to IL-1 β, IL-6 releases.2. The indicated doses of cPLA2 antisense oligonucleotide were then used to block cPLA2 in LPS induced HeLa cells. The process led to a dose-dependent decrease in cPLA2 protein with unnoticeable change of cPLA2 mRNA. Compared with that of LPS added only group, the reduction of IL-1 3 and IL-6 levels in the supernatants of transfected cells following the repression of cPLA2 was observed.These results suggested that cPLA2 might mediate the signaling cascades by which IL-1 β and IL-6 were released in LPS induced HeLa cells.