Prostaglandin E2 suppresses CCL27 production through EP2 and EP3 receptors in human keratinocytes

[摘要] Background: The chemokine CCL27 attracts skin-homing T cells. CCL27 production by keratinocytes is enhanced in skin lesions from patients with atopic dermatitis or psoriasis vulgaris. It is suggested that prostaglandin E-2 (PGE(2)) regulates skin inflammation. Objective: We examined the in vitro effects of PGE(2) On CCL27 production in human keratinocytes. Methods: Keratinocytes were incubated with TNF-alpha in the presence or absence of PGE(2)-CCL27 secretion and mRNA level were analyzed by means of ELISA and RT-PCR, respectively. Nuclear factor kappaB (NF-kappaB)-dependent transcriptional activity was analyzed by using luciferase assays. Results: TNF-alpha increased CCL27 secretion and mRNA levels in parallel to NF-kappaB activity in keratinocytes. NF-kappaB p50 or p65 antisense oligonucleotides suppressed TNF-alpha-induced CCL27 production, indicating the requirement of NF-kappaB for CCL27 production. PGE(2), EP2, or EP3 agonists reduced TNF-alpha-induced CCL27 secretion and mRNA levels in parallel to NF-kappaB activity and CCL2, CCL5, CXCL8, and CXCLIO mRNA levels. Either EP3-specific or dual EP1-EP2 antagonist partially blocked the inhibitory effects of PGE(2) on CCL27 production and NF-KB activity, and the addition of both completely abrogated the inhibition, whereas EP1 or EP4 antagonists were ineffective. Intracellular Ca2+ chelator BAPTA/AM or cyclic adenosine monophosphate (cAMP)-dependent protein kinase inhibitor H-89 partially blocked the inhibitory effects of PGE(2) on CCL27 production and NF-KB activity, and the addition of both completely abrogated the inhibition. PGE(2) or EP3 agonist increased intracellular Ca2+ concentrations. PGE(2) or EP2 agonist increased intracellular cAMP concentrations. Conclusion: PGE(2) might suppress CCL27 production by inhibiting NF-KB activity through EP2-mediated cAMP and EP3-mediated Ca2+ signals. PGE(2) might terminate T cellmediated skin inflammation by inhibiting CCL27 production.

[发布日期] 2004-12-01

[关键词] CCL27;prostaglandin E-2;EP2;EP3;NF-kappa B;cyclic adenosine monophosphate;Ca2(+)