title: Regulation of ABCG1 expression in human keratinocytes and murine epidermis.
abstract: ABCG1, a member of the ATP binding cassette superfamily, facilitates the efflux of cholesterol from cells to HDL. In this study, we demonstrate that ABCG1 is expressed in cultured human keratinocytes and murine epidermis, and induced during keratinocyte differentiation, with increased levels in the outer epidermis. ABCG1 is regulated by liver X receptor (LXR) and peroxisome proliferator-activated receptor-δ (PPAR-δ) activators, cellular sterol levels, and acute barrier disruption. Both LXR and PPAR-δ activators markedly stimulate ABCG1 expression in a dose- and time-dependent fashion. PPAR-γ activators also increase ABCG1 expression, but to a lesser degree. In contrast, activators of PPAR-α, retinoic acid receptor, retinoid X receptor, and vitamin D receptor do not alter ABCG1 expression. In response to increased intracellular sterol levels, ABCG1 expression increases, whereas inhibition of cholesterol biosynthesis decreases ABCG1 expression. In vivo, ABCG1 is stimulated 3-6 h after acute barrier disruption by either tape stripping or acetone treatment, an increase that can be inhibited by occlusion, suggesting a potential role of ABCG1 in permeability barrier homeostasis. Although Abcg1-null mice display normal epidermal permeability barrier function and gross morphology, abnormal lamellar body (LB) contents and secretion leading to impaired lamellar bilayer formation could be demonstrated by electron microscopy, indicating a potential role of ABCG1 in normal LB formation and secretion.
authors.affiliation: Metabolism Section, Veterans Affairs Medical Center, Northern California Institute for Research and Education, University of California at San Francisco, San Francisco, CA 94121, USA. yan.jiang@med.va.gov
authors.forename: Yan J
authors.initials: YJ
authors.lastname: Jiang
authors.forename: Biao
authors.initials: B
authors.lastname: Lu
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Tarling
authors.forename: Peggy
authors.initials: P
authors.lastname: Kim
authors.forename: M-Q
authors.initials: MQ
authors.lastname: Man
authors.forename: Debbie
authors.initials: D
authors.lastname: Crumrine
authors.forename: Peter A
authors.initials: PA
authors.lastname: Edwards
authors.forename: Peter M
authors.initials: PM
authors.lastname: Elias
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Feingold
mesh_terms: D000070998:ATP Binding Cassette Transporter, Subfamily G, Member 1; D018528:ATP-Binding Cassette Transporters / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D000078404:Epidermal Cells; D004817:Epidermis / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D055786:Gene Knockout Techniques; D006801:Humans; D006845:Hydrocarbons, Fluorinated / Q000494:pharmacology; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008074:Lipoproteins / Q000235:genetics* / Q000378:metabolism; D000071518:Liver X Receptors; D051379:Mice; D057093:Orphan Nuclear Receptors / Q000378:metabolism; D047494:PPAR delta / Q000378:metabolism; D010539:Permeability / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013261:Sterols / Q000494:pharmacology; D013449:Sulfonamides / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects; D005466:Fluorocarbons; D000096926:Benzenesulfonamides
chemical_list: D000070998:ATP Binding Cassette Transporter, Subfamily G, Member 1; D018528:ATP-Binding Cassette Transporters; D006845:Hydrocarbons, Fluorinated; D008074:Lipoproteins; D000071518:Liver X Receptors; D057093:Orphan Nuclear Receptors; D047494:PPAR delta; D012333:RNA, Messenger; D013261:Sterols; D013449:Sulfonamides; C419353:ABCG1 protein, human; C487540:ABCG1 protein, mouse; C423915:T0901317; D005466:Fluorocarbons; D000096926:Benzenesulfonamides