Prostaglandin E(2) suppresses CCL27 production through EP2 and EP3 receptors in human keratinocytes.
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 CXCL10 mRNA levels. Either EP3-specific or dual EP1-EP2 antagonist partially blocked the inhibitory effects of PGE(2) on CCL27 production and NF-kappaB activity, and the addition of both completely abrogated the inhibition, whereas EP1 or EP4 antagonists were ineffective. Intracellular Ca(2+) 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-kappaB activity, and the addition of both completely abrogated the inhibition. PGE(2) or EP3 agonist increased intracellular Ca(2+) concentrations. PGE(2) or EP2 agonist increased intracellular cAMP concentrations.


CONCLUSIONS
PGE(2) might suppress CCL27 production by inhibiting NF-kappaB activity through EP2-mediated cAMP and EP3-mediated Ca(2+) signals. PGE 2 might terminate T cell-mediated skin inflammation by inhibiting CCL27 production.
Kanda
Naoko
N
Department of Pathology, Teikyo University School of Medicine, Tokyo, Japan. nmk@med.teikyo-u.ac.jp
Mitsui
Hiroshi
H
Watanabe
Shinichi
S
D002118:Calcium / Q000502:physiology; D002478:Cells, Cultured; D054425:Chemokine CCL27; D019742:Chemokines, CC / Q000096:biosynthesis*; D000242:Cyclic AMP / Q000502:physiology; D015232:Dinoprostone / Q000494:pharmacology*; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism*; D016328:NF-kappa B / Q000502:physiology; D018078:Receptors, Prostaglandin E / Q000502:physiology*; D058307:Receptors, Prostaglandin E, EP2 Subtype; D058308:Receptors, Prostaglandin E, EP3 Subtype; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
C492276:CCL27 protein, human; D054425:Chemokine CCL27; D019742:Chemokines, CC; D016328:NF-kappa B; C545644:PTGER2 protein, human; C545647:PTGER3 protein, human; D018078:Receptors, Prostaglandin E; D058307:Receptors, Prostaglandin E, EP2 Subtype; D058308:Receptors, Prostaglandin E, EP3 Subtype; D014409:Tumor Necrosis Factor-alpha; D000242:Cyclic AMP; D015232:Dinoprostone; D002118:Calcium