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Significant downregulation of transforming growth factor‐β signal transducers in human skin following ultraviolet‐A1 irradiation
Author(s) -
Gambichler T.,
Skrygan M.,
Tomi N.S.,
Breuksch S.,
Altmeyer P.,
Kreuter A.
Publication year - 2007
Publication title -
british journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.304
H-Index - 179
eISSN - 1365-2133
pISSN - 0007-0963
DOI - 10.1111/j.1365-2133.2007.07802.x
Subject(s) - smad , transforming growth factor , photoaging , human skin , in vivo , downregulation and upregulation , messenger rna , medicine , signal transduction , erythema , real time polymerase chain reaction , pathology , cancer research , biology , endocrinology , immunology , dermatology , microbiology and biotechnology , biochemistry , gene , genetics
Summary Background Despite the significant role of the transforming growth factor (TGF)‐β/Smad pathway in cell growth and extracellular matrix regulation, relatively little is known regarding the effect of ultraviolet (UV) radiation on the TGF‐ β /Smad signalling in human skin. Objectives We aimed to investigate the impact of UVA1 and UVB on the mRNA and protein expression of TGF‐ β /Smad signal transducers in human skin in vivo . Methods Fifteen subjects were exposed to 1·5 minimal erythema doses (MED) (4·5 MED cumulative) of UVA1 and UVB over a 3‐day period. Skin biopsies were obtained at 24 and 72 h after the last UV exposure. Real‐time reverse transcription–polymerase chain reaction and immunohistology were performed. Results In the UVA1‐exposed sites (24 h, 72 h), mRNA expression of TGF‐ β 1 and Smad3/4/7 was significantly downregulated as compared with nonirradiated skin sites ( P < 0·05). At 24 h, immunohistology revealed significantly reduced TGF‐ β 1 protein levels in fibroblasts ( P < 0·05). However, mRNA and protein expression of TGF‐ β /Smad proteins observed in UVB‐irradiated sites did not differ significantly from control sites ( P > 0·05). Conclusions In contrast to UVB, UVA1 significantly downregulates the expression of TGF‐ β /Smad proteins in human skin in vivo . The extent to which the acute effects of TGF‐ β /Smad signalling reported in the present paper are related to the beneficial effect of UVA1‐based phototherapy of fibrotic skin conditions and/or to the chronic effects of UV that result in photoaging and cancer remains to be established.