Mucosal IL-10 and TGF-β play crucial roles in preventing LPS-driven, IFN-γ–mediated epithelial damage in human colon explants
Anne Jarry, … , Marc G. Denis, Christian L. Laboisse
Anne Jarry, … , Marc G. Denis, Christian L. Laboisse
Published February 7, 2008
Citation Information: J Clin Invest. 2008;118(3):1132-1142. https://doi.org/10.1172/JCI32140.
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Research Article Gastroenterology

Mucosal IL-10 and TGF-β play crucial roles in preventing LPS-driven, IFN-γ–mediated epithelial damage in human colon explants

Abstract

IL-10 is an immunomodulatory cytokine that plays an obligate role in preventing spontaneous enterocolitis in mice. However, little is known about IL-10 function in the human intestinal mucosa. We showed here that IL-10 was constitutively expressed and secreted by the human normal colonic mucosa, including epithelial cells. Depletion of IL-10 in mucosal explants induced both downregulation of the IL-10–inducible, immunosuppressive gene BCL3 and upregulation of IFN-γ, TNF-α, and IL-17. Interestingly, TGF-β blockade also strongly induced IFN-γ production. In addition, the high levels of IFN-γ produced upon IL-10 depletion were responsible for surface epithelium damage and crypt loss, mainly by apoptosis. Polymyxin B, used as a scavenger of endogenous LPS, abolished both IFN-γ production and epithelial barrier disruption. Finally, adding a commensal bacteria strain to mucosa explant cultures depleted of both IL-10 and LPS reproduced the ability of endogenous LPS to induce IFN-γ secretion. These findings demonstrate that IL-10 ablation leads to an endogenous IFN-γ–mediated inflammatory response via LPS from commensal bacteria in the human colonic mucosa. We also found that both IL-10 and TGF-β play crucial roles in maintaining human colonic mucosa homeostasis.

Authors

Anne Jarry, Céline Bossard, Chantal Bou-Hanna, Damien Masson, Eric Espaze, Marc G. Denis, Christian L. Laboisse

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Figure 5

IFN-γ production upon TGF-β or IL-10 depletion.

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IFN-γ production upon TGF-β or IL-10 depletion. Effect of rhTGF-β upon I...
Effect of rhTGF-β upon IL-10 depletion. (A–C) Mucosa explant cultures were incubated with neutralizing anti–TGF-βRII antibodies (5 μg/ml) or with control goat Ig for 48 h. IFN-γ was examined at the mRNA (real-time PCR; A) and protein (ELISA; B) levels. IL-10 mRNA levels were also determined by real-time PCR (C). Horizontal lines represent mean values of 3 different experiments. (D and E) Mucosa explant cultures were incubated with neutralizing anti–IL-10 antibodies or with the isotype mouse IgG1 (control) for 48 h. The effect on IFN-γ release of incubating IL-10–depleted mucosa explant cultures with rhTGF-β1 (10 ng/ml) was determined into the supernatants, measured by ELISA (D). TGF-β1 mRNA levels were quantified by real-time PCR in control and IL-10–depleted mucosa explant cultures (E). Horizontal lines represent mean values of 4 different experiments. “NS” indicates differences were not significant for the pooled experiments as well as within each experiment.