title: Short-time UVA exposure to human keratinocytes instigated polyunsaturated fatty acid without inducing lipid peroxidation.
abstract: Short-term exposure to ultraviolet A (UVA) radiation can directly injure our skin through inflammatory response and indirectly through oxidative stress, triggering polyunsaturated fatty acid (PUFA) peroxidation in skin cell membrane and formation of DNA adduct, 8-hydroxy-2'-deoxyguanosine (8-OHdG). It is known that UVA exposure leads to photoaging, immunosuppression and skin cancer. However, the changes in PUFA and its oxidized metabolites, and cell cycle after short UVA exposure, are debatable. In this study, human keratinocytes (HaCaT) were exposed to low dose (5 J/cm2) and high dose (20 J/cm2) of UVA and assessed immediately, 8 h, 12 h, and 24 h post-treatment. Both doses showed a transient suppression in S-phase after 8 h of UVA exposure, and G2/M phase arrest after 12-h UVA exposure in the cell cycle but subsequently returned to normal cycle. Also, no observable DNA damage took place, where 8-OHdG levels were below par after 24-h UVA exposure. A dose of 20 J/cm2UVA stimulated significant amount of arachidonic acid, n-3 docosapentaenoic acid, and docosahexaenoic acid (DHA) but lowered adrenic acid and eicospentaenoic acid after 24-h exposure. Among the 43 oxidized PUFA products determined, enzyme-dependent oxidized PUFAs, namely, 14-hydroxy-DHA (HDoHE) level reduced, and 8- and 13-HDoHE levels elevated significantly in a linear trend with post-treatment time. Out of the nonenzymatic oxidized PUFAs, a significant linear trend with post-treatment time was shown on the reduction of 5-F2t-Isoprostane (IsoP), 15-F2t-IsoP, Isofurans, 5-F3t-IsoP, Neurofurans, and 20-HDoHE. Our observations indicate oxidative stress through short UVA exposure on human keratinocytes did not have detrimental consequences.
authors.affiliation: a School of Biological Sciences , The University of Hong Kong , Hong Kong , Hong Kong SAR.
authors.forename: Kin Sum
authors.initials: KS
authors.lastname: Leung
authors.affiliation: a School of Biological Sciences , The University of Hong Kong , Hong Kong , Hong Kong SAR.
authors.forename: Hok Fung
authors.initials: HF
authors.lastname: Chan
authors.affiliation: a School of Biological Sciences , The University of Hong Kong , Hong Kong , Hong Kong SAR.
authors.forename: Ho Hang
authors.initials: HH
authors.lastname: Leung
authors.affiliation: b Institut des Biomolécules Max Mousseron, UMR 5247 CNRS, ENSCM, Université de Montpellier , Montpellier , France.
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Galano
authors.affiliation: b Institut des Biomolécules Max Mousseron, UMR 5247 CNRS, ENSCM, Université de Montpellier , Montpellier , France.
authors.forename: Camille
authors.initials: C
authors.lastname: Oger
authors.affiliation: b Institut des Biomolécules Max Mousseron, UMR 5247 CNRS, ENSCM, Université de Montpellier , Montpellier , France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Durand
authors.affiliation: a School of Biological Sciences , The University of Hong Kong , Hong Kong , Hong Kong SAR.
authors.forename: Jetty Chung-Yung
authors.initials: JC
authors.lastname: Lee
mesh_terms: D000975:Antioxidants / Q000378:metabolism / Q000528:radiation effects*; D016718:Arachidonic Acid / Q000378:metabolism; D002460:Cell Line; D004249:DNA Damage / Q000528:radiation effects; D004281:Docosahexaenoic Acids / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000378:metabolism / Q000528:radiation effects*; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism / Q000528:radiation effects*; D015227:Lipid Peroxidation / Q000528:radiation effects; D018384:Oxidative Stress / Q000528:radiation effects; D012867:Skin / Q000378:metabolism / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D000975:Antioxidants; D005231:Fatty Acids, Unsaturated; C011395:adrenic acid; D004281:Docosahexaenoic Acids; D016718:Arachidonic Acid; C026219:docosapentaenoic acid
keywords: HaCaT; Isoprostanes; UVA; polyunsaturated fatty acids; skin peroxidation