CONTRIBUTION OF UVB AND UVA TO UV- DEPENDENT STIMULATION OF CYCLOOXYGENASE-2 EXPRESSION IN ARTIFICIAL EPIDERMIS.

• TR Number: 334
• Authors: Mahns1,2, A., Wolber2, R., Stäb2, F., Klotz1, L.O., Sies1, H. 1Institut für Biochemie und Molekularbiologie I, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany, 2Beiersdorf AG, Cosmed Forschungszentrum, Unnastraße 48, 20245 Hamburg, Germany.
• Materials Tested: EPI-100-MM, UV (SS), UVA

Both UVB (280–320 nm) and UVA (320–400 nm) radiation lead to an enhanced expression of cyclooxygenase-2 (COX-2) in epidermal cells in various in-vitro and in-vivo models. It is demonstrated here that the expression of COX-2 is induced in artificial human epidermis exposed to simulated solar light (>290 nm). Employing filters eliminating specified regions from the simulated solar spectrum, the UVB and UVA-2 (320–350 nm) regions are shown to fully account for induction of COX-2 mRNA and protein as well as the enhanced production of prostaglandin E2 after irradiation. At the protein level, approximately 70% of the total induction by solar light is due to light in the UVA-2 region. UVA-1 (350–400 nm), visible light and IR radiation are practically ineffective. COX-2 induction by simulated solar light is attenuated in the presence of inhibitors of p38MAPK or of c-Jun-N-terminal kinases (JNK), whereas COX-2 induction by UVA is blocked only by inhibition of JNK. UV-induced COX-2 expression is not affected by inhibition of the MEK 1,2/ERK 1,2 pathway.