title: p38 mitogen-activated protein kinase activation by ultraviolet A radiation in human dermal fibroblasts.
abstract: UVA radiation penetrates deeply into the skin reaching both the epidermis and the dermis. We thus investigated the effects of naturally occurring doses of UVA radiation on mitogen-activated protein kinase (MAPK) activities in human dermal fibroblasts. We demonstrated that UVA selectively activates p38 MAPK with no effect on extracellular-regulated kinases (ERK1-ERK2) or JNK-SAPK (cJun NH2-terminal kinase-stress-activated protein kinase) activities. We then investigated the signaling pathway used by UVA to activate p38 MAPK. L-Histidine and sodium azide had an inhibitory effect on UVA activation of p38 MAPK, pointing to a role of singlet oxygen in transduction of the UVA effect. Afterward, using prolonged cell treatments with growth factors to desensitize their signaling pathways or suramin to block growth factor receptors, we demonstrated that UVA signaling pathways shared elements with growth factor signaling pathways. In addition, using emetine (a translation inhibitor altering ribosome functioning) we detected the involvement of ribotoxic stress in p38 MAPK activation by UVA. Our observations suggest that p38 activation by UVA in dermal fibroblasts involves singlet oxygen-dependent activation of ligand-receptor signaling pathways or ribotoxic stress mechanism (or both). Despite the activation of these two distinct signaling mechanisms, the selective activation of p38 MAPK suggests a critical role of this kinase in the effects of UVA radiation.
authors.affiliation: INSERM Unité 532, Institut de Recherche sur la Peau, Pavilion Bazin, Hôpital Saint-Louis, Paris Cedex, France.
authors.forename: Rozen
authors.initials: R
authors.lastname: Le Panse
authors.forename: Louis
authors.initials: L
authors.lastname: Dubertret
authors.forename: Bernard
authors.initials: B
authors.lastname: Coulomb
mesh_terms: D002478:Cells, Cultured; D004789:Enzyme Activation / Q000528:radiation effects; D005347:Fibroblasts / Q000201:enzymology / Q000528:radiation effects; D006801:Humans; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism / Q000528:radiation effects*; D015398:Signal Transduction / Q000528:radiation effects; D026082:Singlet Oxygen / Q000378:metabolism / Q000528:radiation effects; D012867:Skin / Q000201:enzymology* / Q000528:radiation effects; D014466:Ultraviolet Rays; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D026082:Singlet Oxygen; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases