Activation of Gene Expression of Collagenase and ICAM-1 by UVA Radiation and by Exposure to Singlet Oxygen

Summary

UVA irradiation alone or in conjunction with photosensitizers substantially modulates gene expression. The biological effect of UVA irradiation can be mediated by electron transfer or by a pathway involving singlet oxygen (¹O₂). UVA irradiation or ¹O₂, generated in a dark reaction by thermal decomposition of the endoperoxide of 3,3′-(1,4-naphthylidene) dipropionate, induces gene expression of collagenase (MMP-1) in human skin fibroblasts and of the intercellular adhesion molecule-1 (ICAM-1) in human keratinocytes, respectively. Further supporting evidence for the role of singlet oxygen in the UVA induction of collagenase and ICAM-1 was obtained by examining the modulation of the effects by employing deuterium oxide as a singlet oxygen enhancer or sodium azide as a quencher of singlet oxygen. Using ICAM-1 based luciferase reporter gene constructs, it was shown that ICAM-1 promoter activation induced by UVA radiation as well as by singlet oxygen generated from the endoperoxide of 1,4-naphthylidene dipropionate required the activation of the transcription factor AP-2.