Influence on AP-1 Activation and MMP-1 Expression by UV Irradiation to Human Normal Dermal Fibroblasts

摘要

Solar ultraviolet (UV) radiation has been implicated as a major factor in skin photoaging. Ultrastructural evidence indicates that dermal extracellular materix components such as collagen and elastin fibers are severely damaged in photoaged skin. UVA (320-400 nm) penetrates deeper into the dermis than UVB (290-320 nm) and is responsible for the denaturation of collagen and elastin fibers. It is known that matrix metalloproteases (MMP) such as collagenase (MMP-1) lead to the denaturation. MMP-1 expression is regulated by transcription factor activator protein-1 (AP-1). In the present study, we show AP-1 activation and subsequent MMP-1 production by UVA light in human dermal fibroblasts by using an electrophoretic mobility shift assay (EMSA) and an enzymelinked immunosorbent assay (ELISA), respectively. It is found that these UVA-induced damages are accelerated by hematoporphyrin which is a photosensitive reagent and generates singlet oxygen. These results suggest that the UVA-induced photodamage in dermis is involved in a photosensitizing reaction.