1. ^*Department of Dermatology, Leiden University Medical Center, Leiden, The Netherlands;
2. ^†Department of Molecular and Cellular Neurobiology, Free University, Amsterdam, The Netherlands;
3. ^‡Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands;
4. ^§Numico Research B.V., Wageningen, The Netherlands

Correspondence: Dr Cornelis P. Tensen, Department of Dermatology, Sylvius Laboratory, Room 3042, Wassenaarseweg 72, 2333 AL Leiden, The Netherlands. Email: cp.tensen@azvu.nl

¹Equally contributed to this work.

²Present address: Department of Pharmacology and Pharmacotherapy, Academic Medical Center, Amsterdam, The Netherlands.

Received 30 June 2004; Revised 27 August 2004; Accepted 21 September 2004.

Abstract

The human skin is the only line of defense against UV radiation. A series of responses to protect the skin are induced by UV radiation. In this study, a proteomic approach was used to study these responses. We have performed high-resolution two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) analysis of (solar simulated) UV-exposed reconstructed skin equivalents as well as native skin. Differentially expressed proteins were processed for mass spectrometric analysis, when consistent differences were observed in all individual human skin equivalents. In addition to proteins known to be involved in UV responses (HSP27, MnSOD, and PDX-2), we identified two novel proteins that were downregulated following UV exposure. Further analysis revealed that these proteins were the phosphorylated forms of the actin cytoskeleton modulators cofilin-1 and destrin. The de-phosphorylation of cofilin-1 was confirmed using western blotting of UV-exposed skin equivalents and ex vivo skin protein extracts. In conclusion, our study indicates the potency of a proteomic approach to study UV-induced changes in a tissue culture system mimicking human skin as well as excised human skin.