Annual Meeting of the North American Society for Pediatric Gastroenterology and Nutrition; Orlando, October 22-24, 1998
URSODEOXYCHOLIC ACID (UDC) INHIBITS HGF PRODUCTION IN HUMAN MYELOID CELLS
UDC with established efficacy in chronic cholestasis is also used in patients with IBD/primary sclerosing cholangitis (PSC) and cystic fibrosis (CF) while hepatocyte growth factor (HGF) is critical to the development and repair of the gastrointestinal and the hepatobiliary systems. Since the effect of UDC on HGF production has not been investigated previously, we determined the effect of UDC on constitutive and stimulated HGF expression in the presence/absence of glucocorticoid receptor blocker (mifepristone) by human myeloid cells, key sources of the growth factor in the liver. KG-1 cells (0.5 × 106 cells/ml) in RPMI 1640 5% FCS/1% gln, penicillin/streptomycin were incubated 24 hours at 37°C in CO2 incubator with or without 500 µM UDC, in the presence/absence of TPA (5 × 10 -9 M) and mifepristone (5 µM). Culture supernatants were analyzed for HGF by ELISA. Total RNA was extracted from the cell pellet using Qiagen RNeasy kit, and RT - PCR performed using the Gene Amp EZ rTth RNA PCR kit (Perkin Elmer) with HGF primers. Cells were also stained by indirect immunofluorescence using rabbit antibodies (Santa Cruz Biotech) to NF-κB (p65). UDC decreased constitutive HGF production (n=7, x=33% inhibition) and abolished the increase observed with TPA stimulation (n=8). Inhibition was associated with decreased steady state HGF mRNA levels, and was not prevented by mifepristone (n=5, x=42% inhibition) or increased concentration of FCS to 10% (n=2, x = 75% inhibition) or 20% (n=2, x=51% inhibition). Alcohol (0.05%), used to dissolve the UDC, did not suppress HGF (n=2, x=125% control). Expression of NF-κB and nuclear staining were depressed by UDC in the presence/absence of TPA. Thus, UDC decreases HGF production in myeloid cells by a mechanism that does not depend on the glucocorticoid receptor, but prevents protein kinase C mediated activation and depresses NF-κB expression. Inhibition of HGF, may be an important immunosuppression effect, but potentially deleterious in patients with chronic diseases, such as CF/IBD.
PLENARY SESSION III© 1998 Lippincott Williams & Wilkins, Inc.