title: Contribution of protein kinase A and protein kinase C pathways in ultraviolet B-induced IL-8 expression by human keratinocytes.
abstract: We have previously demonstrated that treatment of the human keratinocyte cell line NCTC 2544 with a UVB dose equivalent to 1h exposure (100 mJ/cm2) results in a significant increase of IL-8 production. In this study, we use specific inhibitors to investigate the role of both PKA- and PKC-mediated pathways in the regulation of UVB-induced IL-8 expression in NCTC 2544 cell line. We show here that the treatment of irradiated human keratinocytes with PKA inhibitors [H89 and PKA inhibitor (PKAi)] induced a significant decrease of IL-8 production at both mRNA and protein levels. However, the regulation of IL-8 production seems to be mediated via a cAMP-independent PKA pathway, since drugs known to enhance cAMP concentrations [PGE2, cholera toxin and dibutyryl cAMP] decrease IL-8 production in irradiated cells by down-regulating NF-kappa B activation in response to UVB radiation. Using PMA (a potent pharmacological activator of PKC) and calphostin C (a specific PKC inhibitor), we demonstrated an up-regulation of IL-8 in NCTC 2544 cells and a down-regulation of the cytokine in UVB-irradiated cells, respectively. We also observed that in our experimental conditions, staurosporine, an inhibitor of both PKC and PMA-stimulated cellular responses, does not involve PKC inhibition in irradiated cells and significantly decreased NF-kappa B activity in response to UVB radiation. Finally, we concluded that a cAMP-independent PKA activation and a PKC-associated pathway are probably involved in the regulation of UVB-induced IL-8 synthesis in human keratinocytes.
authors.affiliation: Laboratoire d'Immunologie, Virologie et Bactériologie, UFR de Pharmacie, EA3796, IFR 53, 1 avenue du Maréchal Juin, 51100 Reims, France.
authors.forename: Alexia
authors.initials: A
authors.lastname: Grandjean-Laquerriere
authors.forename: Richard
authors.initials: R
authors.lastname: Le Naour
authors.forename: Sophie C
authors.initials: SC
authors.lastname: Gangloff
authors.forename: Moncef
authors.initials: M
authors.lastname: Guenounou
mesh_terms: D002460:Cell Line; D002772:Cholera Toxin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015232:Dinoprostone / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000528:radiation effects*; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism*; D015603:Keratinocytes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism / Q000528:radiation effects*; D016328:NF-kappa B / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D015398:Signal Transduction; D019311:Staurosporine / Q000494:pharmacology; D014466:Ultraviolet Rays
chemical_list: D016209:Interleukin-8; D016328:NF-kappa B; D047428:Protein Kinase Inhibitors; D002772:Cholera Toxin; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D019311:Staurosporine; D015232:Dinoprostone