Omega-3 Polyunsatulated Fatty Acids (PUFA) Suppressed Stat-6 Phosphorylation in Cultured Human Conjunctival Fibroblasts

Abstract

Purpose:: Omega-3 polyunsaturated fatty acids (PUFA), such as docosahexaen acid (DHA) and eicosapentaen acid (EPA), have been found to suppress inflammatory diseases as well as cardiovascular diseases. We have previously reported that serum omega-3 PUFA concentration is decreased in AKC and VKC patients, and that omega-3 PUFA suppressed chemokine production in cultured conjunctival fibroblasts. In this study, we investigated the effects of omega-3 PUFA on STAT-6 and NF-kappa B phosphorylation.

Methods:: Human conjunctival fibroblasts were cultured with DHA (100micro-g/ml) for 24 hrs, and stimulated with TNF-alpha (30ng/ml) and IL-4 (30 ng/ml). Eotaxin, RANTES, ICAM-1 and VCAM-1 mRNA expressions in cultured cells were investigated by using realtime-PCR (n=3). STAT-6 and NF-kappa B phosphorylations in fibroblasts stimulated for 6 hours were investigated by western blotting method.

Results:: Eotaxin, RANTES, ICAM-1 and VCAM-1 mRNA expression in stimulated fibroblasts were suppressed by DHA pre-incubation (59%, 64%, 43% and 36% suppression, respectively). NF-kappa B phosphorylation in stimulated fibroblasts were significantly suppressed by DHA pre-incubation. Interestingly, STAT-6 phosphorylation in stimulated fibroblasts were also suppressed by DHA pre-incubation.

Conclusions:: The regulatory effect of omega-3 PUFA chemokine and adhesion molecules expression from conjunctival fibroblasts may affects the severity of allergic disease. Suppressive effects of DHA on STAT-6 and NF-kappa B phosphorylation may participate on this mechanisms.

Keywords: lipids • transcription factors • cytokines/chemokines