MODULATION OF TGF-BETA-1 PRODUCTION FROM HUMAN KERATINOCYTES BY UVB

Transforming growth factor-beta (TGF-beta) plays an important role not only in cell growth control but also in inflammation and immunoregula tion. There are at least five different isoforms of TGF-beta. TGF-beta 1 has a large variety of biological functions including the modulatio n of inflammation and the immune system and has most extensively been studied in skin. Since ultraviolet B (UVB) is known to induce skin ery thema and immunosuppression, we sought to examine whether UVB would al ter the expression and production of TGF-beta 1 in normal human kerati nocytes. Using reverse transcription-polymerase chain reaction (RT-PCR ), constitutive expression of TGF-beta 1 mRNA was detected in keratino cytes and the level of TGF-beta 1 mRNA was increased 4 and 8 h after 3 00 J/m(2) UVB irradiation. Production of TGF-beta 1 protein in culture supernatants assayed by ELISA was also increased at 24 h after irradi ation. Cycloheximide treatment blocked this TGF-beta 1 protein inducti on indicating de novo protein synthesis of TGF-beta 1 from keratinocyt es induced by UVB. These results suggest a possible role for TGF-beta 1 in UVB-induced skin inflammation and immunosuppression.