title: Non-selective distribution of isomeric cholesterol hydroperoxides to microdomains in cell membranes and activation of matrix metalloproteinase activity in a model of dermal cells.
abstract: Cholesterol hydroperoxides (ChOOHs) are included as lipid peroxidation products in the skin exposed to ultraviolet (UV) light irradiation. They may exert physicochemical actions affecting biomembrane rigidity because cholesterol is one of the major components of cell membranes. We investigated the distribution of isomeric ChOOHs in heterogeneous cell membranes with different lipid profiles using mouse fibroblast NIH-3T3 cells as a model of the dermis. Before and after UVA irradiation in the presence of hematoporphyrin, cell membranes were partitioned to microdomains (lipid rafts and caveolae) containing a higher amount of cholesterol and non-microdomains (containing a lower amount of cholesterol) by ultracentrifugation. By a combination of diphenylpyrenylphosphine-thin-layer chromatography blotting analyses and gas chromatography-electron ionization-mass spectrometry/selected ion monitoring analyses, ChOOH isomers were determined as their trimethylsilyloxyl derivatives. Cholesterol 5α-, 7α- and 7β-hydroperoxide were found as isomeric ChOOHs before irradiation. The amounts of the three ChOOH isomers increased significantly after photoirradiation for 2h. No difference was observed between microdomains and non-microdomains with regard to the ratio of the amounts of isomeric ChOOHs to that of cholesterol, suggesting that these ChOOH isomers were distributed equally in both parts depending on cholesterol content. When cells were treated with a purified mixture of ChOOH isomers, cell membranes incorporated ChOOHs into microdomains as well as non-microdomains evenly. Cellular matrix metalloproteinase-9 (MMP-9) activity was elevated by treatment with the purified mixture of ChOOH isomers. These results strongly suggest that ChOOHs accumulate in cell membranes irrespective of the heterogeneous microstructure and promote MMP activity if dermal cells are exposed to photodynamic actions.
authors.affiliation: Department of Food Science, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Nakamura
authors.forename: Ayako
authors.initials: A
authors.lastname: Noma
authors.forename: Sachiko
authors.initials: S
authors.lastname: Shimada
authors.forename: Nanase
authors.initials: N
authors.lastname: Ishii
authors.forename: Noriko
authors.initials: N
authors.lastname: Bando
authors.forename: Yoshichika
authors.initials: Y
authors.lastname: Kawai
authors.forename: Junji
authors.initials: J
authors.lastname: Terao
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000737:chemistry*; D002784:Cholesterol / Q000031:analogs & derivatives* / Q000737:chemistry; D002855:Chromatography, Thin Layer; D020405:Dermis / Q000166:cytology; D008401:Gas Chromatography-Mass Spectrometry; D006415:Hematoporphyrins / Q000737:chemistry; D007536:Isomerism; D015227:Lipid Peroxidation; D020780:Matrix Metalloproteinase 9 / Q000737:chemistry / Q000378:metabolism*; D021962:Membrane Microdomains / Q000737:chemistry*; D051379:Mice; D008954:Models, Biological; D041681:NIH 3T3 Cells; D014466:Ultraviolet Rays
chemical_list: D006415:Hematoporphyrins; C002843:cholesterol hydroperoxide; D002784:Cholesterol; D020780:Matrix Metalloproteinase 9
keywords: 5α-hydroxycholesterol; 7α-hydroxycholesterol; 7β-hydroxycholesterol; Ch5αOH; Ch5αOOH; Ch7αOH; Ch7αOOH; Ch7βOH; Ch7βOOH; ChOOH; Cholesterol hydroperoxide; DMEM; DPPP; Dulbecco's modified Eagle's medium; GC-EI-MS; Lipid rafts; MMP; Matrix metalloproteinase; Microdomain; SIM; StOH; StOOH; TLC; UVA; UVA irradiation; cholesterol 5α-hydroperoxide; cholesterol 7α-hydroperoxide; cholesterol 7β-hydroperoxide; cholesterol hydroperoxide; diphenylpyrenylphosphine; gas chromatography–electron ionization-mass spectrometry; hydroxylsitosterol; matrix metalloproteinase; selected ion monitoring; thin-layer chromatography; ultraviolet-A; β-sitosterol hydroperoxide