Leilei Fang1, Zhi Pang2, Weigang Shu1, Wei Wu1, Mingming Sun1, Yingzi Cong3, Zhanju Liu1. 1. Department of Gastroenterology, The Shanghai Tenth People's Hospital of Tongji University, Shanghai, China. 2. Department of Gastroenterology, Suzhou Municipal Hospital Affiliated to Nanjing Medical University, Suzhou, China. 3. Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, Texas.
Abstract
Background: Anti-tumor necrosis factor (TNF) therapy appears to be effective in the treatment of Crohn's disease (CD), a chronic inflammatory disease of the gastrointestinal tract. However, the mechanisms involved are not completely understood. Methods: Fifty-seven active CD patients were enrolled, and cytokine profiles in colonic biopsies of patients with active CD receiving anti-TNF monoclonal antibody (mAb) (infliximab [IFX]) treatment were determined using quantitative real-time polymerase chain reaction (qRT-PCR). Colonic biopsies of active CD patients and healthy donors were cultured with IFX in vitro, and cytokine profiles were measured by qRT-PCR. Peripheral blood (PB)-CD4+ T cells were stimulated with anti-CD3 and anti-CD28 mAbs in the presence of human immunoglobin (HIg), IFX, recombinant human TNF-α converting enzyme (rhTACE), and aryl hydrocarbon receptor (AhR) inhibitor (CH-223191), respectively, to determine interleukin (IL)-22 expression by CD4+ T cells. Caco2 cells were also utilized to study their potential role in modulating epithelial cell barrier repairs in vitro. Results: IFX therapy markedly upregulated IL-22 mRNA expression in the gut mucosa of CD patients. In vitro treatment with IFX greatly promoted CD CD4+ T cells to express IL-22, which was inhibited by rhTACE, indicating that reverse signaling through binding to membrane-bound TNF mediates anti-TNF-induced IL-22 expression of CD CD4+ T cells. However, blockade of AhR markedly inhibited anti-TNF-induced IL-22+CD4+ T (Th22) cell differentiation in CD patients. Moreover, treatment with IL-22 induced intestinal epithelial cell expression of tight junction proteins (eg, claudin1 and ZO-1) and facilitated transepithelial resistance, indicating that IL-22 protects intestinal mucosa from inflammation via maintenance of epithelial barrier integrity. Conclusions: Our results uncover a novel mechanism whereby anti-TNF therapy upregulates IL-22 production in CD patients through promoting Th22 cell differentiation and contributes to intestinal epithelial barrier repairs.
Background: Anti-tumor necrosis factor (TNF) therapy appears to be effective in the treatment of Crohn's disease (CD), a chronic inflammatory disease of the gastrointestinal tract. However, the mechanisms involved are not completely understood. Methods: Fifty-seven active CDpatients were enrolled, and cytokine profiles in colonic biopsies of patients with active CD receiving anti-TNF monoclonal antibody (mAb) (infliximab [IFX]) treatment were determined using quantitative real-time polymerase chain reaction (qRT-PCR). Colonic biopsies of active CDpatients and healthy donors were cultured with IFX in vitro, and cytokine profiles were measured by qRT-PCR. Peripheral blood (PB)-CD4+ T cells were stimulated with anti-CD3 and anti-CD28 mAbs in the presence of human immunoglobin (HIg), IFX, recombinant humanTNF-α converting enzyme (rhTACE), and aryl hydrocarbon receptor (AhR) inhibitor (CH-223191), respectively, to determine interleukin (IL)-22 expression by CD4+ T cells. Caco2 cells were also utilized to study their potential role in modulating epithelial cell barrier repairs in vitro. Results:IFX therapy markedly upregulated IL-22 mRNA expression in the gut mucosa of CDpatients. In vitro treatment with IFX greatly promoted CD CD4+ T cells to express IL-22, which was inhibited by rhTACE, indicating that reverse signaling through binding to membrane-bound TNF mediates anti-TNF-induced IL-22 expression of CD CD4+ T cells. However, blockade of AhR markedly inhibited anti-TNF-induced IL-22+CD4+ T (Th22) cell differentiation in CDpatients. Moreover, treatment with IL-22 induced intestinal epithelial cell expression of tight junction proteins (eg, claudin1 and ZO-1) and facilitated transepithelial resistance, indicating that IL-22 protects intestinal mucosa from inflammation via maintenance of epithelial barrier integrity. Conclusions: Our results uncover a novel mechanism whereby anti-TNF therapy upregulates IL-22 production in CDpatients through promoting Th22 cell differentiation and contributes to intestinal epithelial barrier repairs.