IL-10 REGULATES EXPRESSION OF CYTOPLASMIC PHOSPHOLIPASE A₂ AND CYCLOOXYGENASE-2 IN HUMAN MESANGIAL CELLS

Wu Y-J, Chen RH, Zhang Ai-H

Nanjing Medical University, Nanjing, China

Objective: IL-10 potently inhibited the expression of pro-inflammatory cytokines (IL-1b, TNF-a, etc) in human mesangial cells (HMC). The present study was to investigate the effect of IL-10 on IL-1b-induced prostaglandin E₂ (PGE₂) release, cytoplasmic phospho-lipase A₂ (cPLA₂) and cyclooxygenase-2 (COX-2) expression in human mesangial cells and to examine whether IL-10 has effect on the biological function of IL-1b.

Methods: The PGE₂ concentration in supernatants of HMC was measured by radioimmunoassay. The cPLA₂ and COX-2 mRNA expression and protein production were measured by RT-PCR and Western Blot, respectively.

Results: HMC produced increased amounts of PGE₂, cPLA₂ and COX-2 after treatment with IL-1b. IL-10 inhibited IL-1b-elicited PGE₂ production, as well as cPLA₂ and COX-2 mRNA and protein expression in a concentration-dependent fashion. IL-10 at 20 ng/ml completely inhibited IL-1b-induced PGE₂ release.

Conclusion: The results indicated that IL-10 reversed the IL-1b-induced release of PGE₂ and expression of cPLA₂ and COX-2. These data suggested that IL-10 could exert anti-inflammatory actions at several levels, which not only inhibited the production of pro-inflammatory cytokines but also suppressed their biological function.

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