title: Ultraviolet B irradiation increases keratin 1 and keratin 10 expressions in HaCaT keratinocytes via TRPV1 activation and ERK phosphorylation.
abstract: In this study, we characterized the effect of ultraviolet B (UVB) irradiation with or without epidermal growth factor (EGF) on the regulation of keratinocyte differentiation under physiological concentration of Ca2+(1.8 mM). In addition, growth factor deprivation used to measure signal transduction and kinase phosphorylation in many studies is physiologically unreal. Therefore, 1% of serum was also included in all experiment. We found that UVB irradiation Ca2+dependently induced morphological differentiation and increased keratin 1 and 10 (K1/K10) expressions. Both were inhibited by treatment of cells with EGF. In quiescent cells, phosphorylation of ERK was stimulated by acute EGF treatment, while it rapidly desensitized in chronic EGF treatment or 1% serum exposure. UVB irradiation-induced keratinocyte differentiation required Ca2+influx through TRPV1. Ca2+-dependent phosphorylation of ERK was responsible for the expression of K1/10. Cotreatment of cells with EGF during UVB irradiation inhibits the UVB irradiation-induced differentiation by desensitizing ERK phosphorylation.
authors.affiliation: Division of Plastic Surgery, Department of Surgery, Chi Mei Medical Center, Tainan, Taiwan, Republic of China.
authors.forename: Kuo-Feng
authors.initials: KF
authors.lastname: Huang
authors.affiliation: Department of Biology and Anatomy, National Defense Medical Center, Taipei, Taiwan, Republic of China.
authors.forename: Kuo-Hsing
authors.initials: KH
authors.lastname: Ma
authors.affiliation: Department of Microbiology, Soochow University, Taipei, Taiwan, Republic of China.
authors.forename: Pei-Shan
authors.initials: PS
authors.lastname: Liu
authors.affiliation: Department of Biochemistry, National Defense Medical Center, Taipei, Taiwan, Republic of China.
authors.forename: Bo-Wei
authors.initials: BW
authors.lastname: Chen
authors.affiliation: Department of Biochemistry, National Defense Medical Center, Taipei, Taiwan, Republic of China.
authors.forename: Sheau-Huei
authors.initials: SH
authors.lastname: Chueh
mesh_terms: D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation / Q000528:radiation effects*; D002460:Cell Line; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D053556:Keratin-1 / Q000378:metabolism; D053550:Keratin-10 / Q000378:metabolism; D015603:Keratinocytes / Q000378:metabolism / Q000528:radiation effects*; D010766:Phosphorylation; D050916:TRPV Cation Channels / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: C507493:KRT10 protein, human; D053556:Keratin-1; D050916:TRPV Cation Channels; C494482:TRPV1 protein, human; D053550:Keratin-10; D048049:Extracellular Signal-Regulated MAP Kinases; D002118:Calcium
keywords: calcium influx; epidermal growth factor; keratinocyte differentiation