PENETRATION OF KERATINOCYTE-DERIVED CYTOKINES INTO BASEMENT-MEMBRANE

Keratinocytes are known to produce a wide variety of cytokines which a re believed to play a significant role in cutaneous inflammatory and i mmunologic reactions. Considering the array of proteolytic enzymes pre sent in the skin and the transient nature of cytokines produced from k eratinocytes, it is unclear whether cytokines released by keratinocyte s cross the basement membrane and contribute to distal inflammatory an d immune reactions, To investigate the ability oi cytokines released f rom human keratinocytes to cross basement membrane, we used a two cham ber culture model. Keratinocytes were plated in the upper chamber coat ed with a reconstituted basement membrane matrix (matrigel) on a micro porous membrane. To augment cytokine production, we exposed keratinocy tes to 300 J/m(2) UVB; 24 h later the supernatants were collected, and the levels of cytokine were measured by ELISA, IL-1 alpha, IL-6, and TNF-alpha were found to be increased after UVB irradiation in the uppe r chamber, and significant amounts (70-80%) of each cytokine were dete cted in the lower chamber. Our results indicate that keratinocyte-deri ved cytokines are available for interactions below the basement membra ne and present circumstantial evidence that the production of those cy tokines from keratinocytes contributes to the elevation of circulation after the UVB exposure. (C) 1997 Wiley-Liss, Inc.