Communication between monocytes, fibroblasts, and hepatocytes in the liver constitute an important feedback pathway in inflammation. Interleukin-1 (ILI) is a key mediator in all three cell types and is directly involved in the liver response to inflammatory stimuli. Recent evidence suggests that the Interleukin-1 Type II receptor (IL-1 Ilr) serves as an endogenous inhibitor of IL-1. We hypothesized that overexpression of the soluble IL-1 Ilr in hepatocytes would inhibit IL-1β mediated inflammation by hepatocytes, fibroblasts, and monocytes. To test this hypothesis, transfection of the human hepatoma cell line HepG2 was optimized using a β-galactosidase reporter plasmid and Lipofectamine®, A mammalian expression vector containing the human IL-1 Ilr cDNA (provided by U.Gubler) was then used to transfect HepG2 cells. Soluble IL-1 Ilr was detectable by ELISA in the supernatents of transfected HepG2 cells (1500-4500 pg/ml) 3-5 days after transfection. The same supernatents were found to bind IL-1 as determined by decreased IL-I ïïr ELISA detection in the presence of recombinant IL-1β. When transfected HepG2 supernatents were incubated with human gingival fibroblasts in the presence of IL-1β (100 pg/ml), interleukin-8 production was completely inhibited (as measured by ELISA in supernatents) whereas, IL-8 induction was unaffected in fibroblasts treated with control and sham-transfected conditioned médias (ANOVA p=.001). IL-1 induction of IL-8 in HepG2 cells and human monocytes was not inhibited by the presence of soluble IL-1 Ilr from transfected cells. These results suggest that the inhibitory effects of soluble IL-1 Ilr are cell dependent and demonstrate the potential for gene delivery to parenchymal cells of the liver to inhibit cytokine mediated inflammation.
|Original language||English (US)|
|Publication status||Published - Dec 1 1996|
ASJC Scopus subject areas
- Molecular Biology