title: Plasma lipoproteins as mediators of the oxidative stress induced by UV light in human skin: a review of biochemical and biophysical studies on mechanisms of apolipoprotein alteration, lipid peroxidation, and associated skin cell responses.
abstract: There are numerous studies concerning the effect of UVB light on skin cells but fewer on other skin components such as the interstitial fluid. This review highlights high-density lipoprotein (HDL) and low-density lipoprotein (LDL) as important targets of UVB in interstitial fluid. Tryptophan residues are the sole apolipoprotein residues absorbing solar UVB. The UVB-induced one-electron oxidation of Trp produces (•)Trp and (•)O2 (-) radicals which trigger lipid peroxidation. Immunoblots from buffered solutions or suction blister fluid reveal that propagation of photooxidative damage to other residues such as Tyr or disulfide bonds produces intra- and intermolecular bonds in apolipoproteins A-I, A-II, and B100. Partial repair of phenoxyl tyrosyl radicals (TyrO(•)) by α -tocopherol is observed with LDL and HDL on millisecond or second time scales, whereas limited repair of α -tocopherol by carotenoids occurs in only HDL. More effective repair of Tyr and α -tocopherol is observed with the flavonoid, quercetin, bound to serum albumin, but quercetin is less potent than new synthetic polyphenols in inhibiting LDL lipid peroxidation or restoring α -tocopherol. The systemic consequences of HDL and LDL oxidation and the activation and/or inhibition of signalling pathways by oxidized LDL and their ability to enhance transcription factor DNA binding activity are also reviewed.
authors.affiliation: Faculdade de Medicina de Lisboa, Hospital de Santa Maria, Clínica Dermatologica Universitaria, Avenida Professor Egas Moniz, 1699 Lisboa Codex, Portugal.
authors.forename: Paulo
authors.initials: P
authors.lastname: Filipe
authors.forename: Patrice
authors.initials: P
authors.lastname: Morlière
authors.forename: João N
authors.initials: JN
authors.lastname: Silva
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Mazière
authors.forename: Larry K
authors.initials: LK
authors.lastname: Patterson
authors.forename: João P
authors.initials: JP
authors.lastname: Freitas
authors.forename: R
authors.initials: R
authors.lastname: Santus
mesh_terms: D001053:Apolipoproteins / Q000097:blood*; D055592:Biophysical Phenomena; D006801:Humans; D015227:Lipid Peroxidation / Q000528:radiation effects*; D018384:Oxidative Stress / Q000528:radiation effects*; D012867:Skin / Q000378:metabolism* / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D001053:Apolipoproteins