Interleukin-10 and Nerve Growth Factor

The intestinal mucosa is in a constant state of controlled inflammation, but the processes whereby this occurs are poorly understood. The aims of this study were to look at the role of IL10 and NGF in intestinal epithelial cell regulation. The human colon epithelial cell line T84, HT29 and CACO-2 were used. RT-PCR, flow cytometry analysis and immunohistochemistry were applied to measure the cytokine changes in epithelial cells induced by recombinant cholera toxin and its B subunit , IL-10 and NGF. Cholera toxin B subunit caused selective dose dependent increased mRNA for IL-10 in T84 cells and the protein in T84, HT-29 and CACO-2 cells. IL-10 dose dependently selectively increased NGF mRNA in T84 cells and intracellular protein synthesis in all 3 epithelial cell lines. The effect of NGF was reciprocal, selective and dose dependent since it increased mRNA for IL-10 and IL-10 synthesis. Our results suggest that the epithelium may actively participate in downregulation through innate mechanisms involving IL10 and NGF. The reciprocal interaction suggests for the first time that NGF may be involved in local downregulation by mucosal epithelium, and thus may play a potent protective role in response to injury, by prevention of undue inflammation.