REGULATION OF NFIL-6 AND IL-6 EXPRESSION BY BASIC FIBROBLAST GROWTH-FACTOR IN OSTEOBLASTS

We determined whether basic fibroblast growth factor (bFGF) regulated the expression of IL-6 and NFIL-G in osteoblasts. In mouse osteoblasti c MC3T3-E1 cells, bFGF (10(-8) M) increased NFIL-6 mRNA 2-fold at 30 m inutes and 3-fold at 2 h, IL-6 mRNA was increased by bFGF 10(-8) M aft er 1 h, IL-6 protein,vas detectable in control cultures but was signif icantly increased by bFGF (10-(8) M) at 4 h, Immunofluorescence analys is of MC3T3-E1 cells showed primarily cytoplasmic and perinuclear NFIL -6 staining in control cultures while hFGF-treated cells showed increa sed NFIL-6 staining at 2 and 4 h, Western blotting revealed that bFGF increased NFIL-6 protein at 2 h, In calvarial mouse osteoblasts,bFGF 1 0(-8) M induced IL 6 mRNA as early as 1 h and significantly increased IL-S protein levels as early as 2 h, In conclusion, bFGF stimulates IL -6 and NFIL-6 mRNA in osteoblasts. The increase in NFIL-6 mRNA was ass ociated with increased NFIL-6 protein, The increase in IL-6 mRNA was a lso associated with increased IL-6 protein. We propose that activation s of NFIL-6 and IL-6; may be important mediators of the effects of bFG F on bone cells.