title: Effects of UVB irradiation on keratinocyte growth factor (KGF) and receptor (KGFR) expression in cultured human keratinocytes.
abstract: Keratinocyte growth factor (KGF) and its receptor (KGFR) are thought to play important roles in normal keratinocyte growth and differentiation. Since UVB radiation is known to influence keratinocyte growth, we sought to determine whether UVB would alter the expression of KGF and KGFR. Using a reverse-transcription coupled polymerase chain reaction (RT-PCR), the present study examined the expression of KGF and KGFR mRNA in cultured normal human keratinocytes exposed to UVB irradiation. Total cellular RNA was extracted from cultured keratinocytes at various time points after irradiation, reverse transcribed and used for PCR amplification using primers specific for KGF and KGFR. Constitutive expression of KGFR mRNA, but not KGF mRNA, was detected in normal cultured human keratinocytes. After UVB irradiation at 300 J/m2, the KGF mRNA remained undetectable while the KGFR mRNA level was significantly decreased. The down-regulation of KGFR mRNA expression was also confirmed by Northern blot analysis. Immunohistochemical studies demonstrated a decreased positive signal of KGFR in human keratinocytes after UVB irradiation. Our results suggest a possible role for the KGF-KGFR signalling pathway in the skin after exposure to UVB, and that UVB-induced growth inhibition of keratinocytes in hyperproliferative skin disorders may be related to downregulation of KGFR.
authors.affiliation: Division of Dermatology, Sunnybrook Health Science Centre, University of Toronto, Canada.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhou
authors.forename: H S
authors.initials: HS
authors.lastname: Lee
authors.forename: F
authors.initials: F
authors.lastname: Kooshesh
authors.forename: H
authors.initials: H
authors.lastname: Fujisawa
authors.forename: D N
authors.initials: DN
authors.lastname: Sauder
authors.forename: S
authors.initials: S
authors.lastname: Kondo
mesh_terms: D002478:Cells, Cultured; D017931:DNA Primers; D004307:Dose-Response Relationship, Radiation; D051526:Fibroblast Growth Factor 10; D051523:Fibroblast Growth Factor 7; D005346:Fibroblast Growth Factors; D006133:Growth Substances / Q000096:biosynthesis*; D006801:Humans; D007150:Immunohistochemistry; D007231:Infant, Newborn; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects*; D008297:Male; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis; D051497:Receptor, Fibroblast Growth Factor, Type 2; D017468:Receptors, Fibroblast Growth Factor; D017978:Receptors, Growth Factor / Q000096:biosynthesis*; D012867:Skin / Q000166:cytology* / Q000528:radiation effects; D014158:Transcription, Genetic / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D017931:DNA Primers; C496453:FGF7 protein, human; D051526:Fibroblast Growth Factor 10; D006133:Growth Substances; D012333:RNA, Messenger; D017468:Receptors, Fibroblast Growth Factor; D017978:Receptors, Growth Factor; D051523:Fibroblast Growth Factor 7; D005346:Fibroblast Growth Factors; D051497:Receptor, Fibroblast Growth Factor, Type 2; C065104:keratinocyte growth factor receptor