KERATINOCYTE GROWTH-FACTOR EXPRESSION IN THE MESENCHYMAL CELLS OF HUMAN AMNION

Amnion epithelial and mesenchymal cells were separated by differential protease treatment, and the separated cells were maintained in monola yer culture. Keratinocyte growth factor (KGF) mes senger RNA (mRNA) wa s readily detected by Northern analysis of amnion mesenchymal cell tot al RNA (10 mu g) but not in amnion epithelial cells. Treatment of the amnion mesenchymal cells in serum-free medium with tetradecanoyl phorb ol acetate (1 nM) caused an increase in the level of KGF mRNA. Forskol in treatment also caused an increase in KGF mRNA but not to the levels attained with tetradecanoyl phorbol acetate treatment. Dexamethasone (1 nM) treatment of these cells effected a reduction in the level of K GF mRNA. Prolonged maintenance of mesenchymal cells in serum-free medi um also was associated with an increase in the level of KGF mRNA. Trea tment with a variety of other agents, viz., interleukin (IL)-1, IL-6 p lus or minus IL-6 soluble receptor, IL-11, oncostatin M, epidermal gro wth factor (EGF), and transforming growth factor-beta did not modify t he level of KGF mRNA. Treatment of amnion epithelial cells with KGF ca used an increase in the rate of [H-3]thymidine incorporation, but the rate of cell replication induced by KGF was less than that induced by treatment with EGF. Transforming growth factor-beta treatment inhibite d basal and EGF-and KGF- stimulated amnion epithelial cell replication . The findings of this study are indicative that KGF is expressed in h uman amnion mesenchymal cells, and that KGF may act on the epithelial cells of this tissue.