The Effect of All-Trans-Retinoic Acid and Ursolic Acid on the Ultraviolet A Radiation Induced AP-1 (Fos/Jun) Activity in Cultured Human Dermal Fibroblasts

Kim, Hyun Cheol; Yang, Joon Sung; Chae, Young Soo; Suh, Kee Suck; Kim, Sang Tae

Abstract

BACKGROUND: Recently, UVB irradiation was found to activate AP-1, which is known to be a major enhancer factor of the collagenase gene. However, tbe effect of UVA irradiation on the activity of AP 1 in derrnal fibroblasts is unclear. Although all trans-retinoic acid(tRA) has been known to prevent. the AP 1 and collagenase stimulatory effect of UVB irradiation, the effect of tRA and ursolic acid(UsA) on the enhancement of AP-1 activity hy UVA irradiation is unknown.
OBJECTIVE
In this stuc y, the effect of UVA irradiation on the AP-1 activity in cultured human dermal fibroblasts was studied. The effect. of tRA and UsA on the enhancement of AP-1 activity by UVA irradiation was also investigated.
METHODS
Confluent human dermal fibroblasts were irradiated with 15J/cm of UVA. Drugs were administered and kept in a culture rnedia for 12 hrs before or immediately after UVA irra diation. Nuclear protein extracts were isolated 12 hrs after UVA irradiation and were subjected to gel retardation assay ising oligolabeled DNA probe for AP l binding site.
RESULTS
1. The activity of AP-1 was increased by UVA irradiation and prominent activation was detected at 6 and 12 hrs postirradiation. 2. Compared to the UVA irradiated group, tRA and the high concentration(10(-5)M) of UsA administered before or al ter UVA irradiation inhibited the increase of AP-1 activity.
CONCLUSION
These res ilts suggest that UVA irradiation enhance the AP-1 activity, which is known to be a major er hancer factor of the collagenase gene, and tRA and UsA downregulate the 1JVA induced AP-l activity enhancement.