title: UVA and UVB decrease the expression of CD44 and hyaluronate in mouse epidermis, which is counteracted by topical retinoids.
abstract: The transmembrane glycoprotein CD44 is currently thought to be the main cell surface receptor for the glycosaminoglycan hyaluronate. We previously showed that (1) CD44 regulate keratinocyte proliferation; (2) topical retinoids dramatically increase the expression of CD44, hyaluronate and hyaluronate synthase (HAS)s in mouse epidermis; (3) topical retinaldehyde restores the epidermal thickness and CD44 expression which are correlated with clinical improvement in lichen sclerosus et atrophicus lesions; and (4) retinaldehyde-induced proliferative response of keratinocytes is a CD44-dependent phenomenon and requires the presence of HB-EGF, erbB1 and matrix metalloproteinases. In this study, we analyzed the effect of UV irradiation on the levels of epidermal hyaluronate and CD44 in mice, as well as its potential prevention by topical retinoids. UVA (10 J/cm(2)) or UVB (1 J/cm(2)) irradiation significantly decreased the expression of CD44 and hyaluronate in the epidermis of hairless mice after 2 h. Expression of both epidermal CD44 and hyaluronate was reconstituted within 24 h. Topical application of retinaldehyde for 3 days prior to UVA or UVB irradiation prevented the decrease of CD44 and hyaluronate expression. Topical retinol and retinoic acid also increased the basal levels of epidermal CD44 and hyaluronate, although their preventive effect on UV-induced decrease of these molecules was less pronounced as compared to topical retinaldehyde. These data confirm the relationships between retinoid and CD44 pathways, although the primary target(s) of UV leading to CD44 and hyaluronate degradation remain to be elucidated.
authors.affiliation: Department of Dermatology, DHURDV, University Hospital of Geneva, Geneva, Switzerland.
authors.forename: Emel
authors.initials: E
authors.lastname: Calikoglu
authors.forename: Olivier
authors.initials: O
authors.lastname: Sorg
authors.forename: Christian
authors.initials: C
authors.lastname: Tran
authors.forename: Denise
authors.initials: D
authors.lastname: Grand
authors.forename: Pierre
authors.initials: P
authors.lastname: Carraux
authors.forename: Jean-Hilaire
authors.initials: JH
authors.lastname: Saurat
authors.forename: Gürkan
authors.initials: G
authors.lastname: Kaya
mesh_terms: D000287:Administration, Topical; D000818:Animals; D004817:Epidermis / Q000502:physiology / Q000528:radiation effects*; D018960:Hyaluronan Receptors / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D006820:Hyaluronic Acid / Q000378:metabolism / Q000528:radiation effects*; D007700:Kinetics; D051379:Mice; D008812:Mice, Hairless; D012172:Retinaldehyde / Q000008:administration & dosage / Q000494:pharmacology; D014466:Ultraviolet Rays
chemical_list: D018960:Hyaluronan Receptors; D006820:Hyaluronic Acid; D012172:Retinaldehyde