The transcription factor IFN regulatory factor–4 controls experimental colitis in mice via T cell–derived IL-6
Jonas Mudter, … , Michael Lohoff, Markus F. Neurath
Jonas Mudter, … , Michael Lohoff, Markus F. Neurath
Published July 1, 2008; First published June 5, 2008
Citation Information: J Clin Invest. 2008;118(7):2415-2426. https://doi.org/10.1172/JCI33227.
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Research Article Gastroenterology

The transcription factor IFN regulatory factor–4 controls experimental colitis in mice via T cell–derived IL-6

Abstract

The proinflammatory cytokine IL-6 seems to have an important role in the intestinal inflammation that characterizes inflammatory bowel diseases (IBDs) such as Crohn disease and ulcerative colitis. However, little is known about the molecular mechanisms regulating IL-6 production in IBD. Here, we assessed the role of the transcriptional regulator IFN regulatory factor–4 (IRF4) in this process. Patients with either Crohn disease or ulcerative colitis exhibited increased IRF4 expression in lamina propria CD3+ T cells as compared with control patients. Consistent with IRF4 having a regulatory function in T cells, in a mouse model of IBD whereby colitis is induced in RAG-deficient mice by transplantation with CD4+CD45RBhi T cells, adoptive transfer of wild-type but not IRF4-deficient T cells resulted in severe colitis. Furthermore, IRF4-deficient mice were protected from T cell–dependent chronic intestinal inflammation in trinitrobenzene sulfonic acid– and oxazolone-induced colitis. In addition, IRF4-deficient mice with induced colitis had reduced mucosal IL-6 production, and IRF4 was required for IL-6 production by mucosal CD90+ T cells, which it protected from apoptosis. Finally, the protective effect of IRF4 deficiency could be abrogated by systemic administration of either recombinant IL-6 or a combination of soluble IL-6 receptor (sIL-6R) plus IL-6 (hyper–IL-6). Taken together, our data identify IRF4 as a key regulator of mucosal IL-6 production in T cell–dependent experimental colitis and suggest that IRF4 might provide a therapeutic target for IBDs.

Authors

Jonas Mudter, Lioubov Amoussina, Mirjam Schenk, Jingling Yu, Anne Brüstle, Benno Weigmann, Raja Atreya, Stefan Wirtz, Christoph Becker, Arthur Hoffman, Imke Atreya, Stefan Biesterfeld, Peter R. Galle, Hans A. Lehr, Stefan Rose-John, Christoph Mueller, Michael Lohoff, Markus F. Neurath

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Figure 1

IRF4 expression is increased in inflammatory bowel diseases.

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IRF4 expression is increased in inflammatory bowel diseases. (A) Immunof...
(A) Immunofluorescence staining of human mucosal cryosections for IRF4. Cryosections of gut specimens from control patients and IBD patients (n = 10 per group) were stained with antibodies against IRF4 (red). Nuclei were counterstained with DAPI (blue). Original magnification, ×300. (B) Quantitative assessment of IRF4-positive cells. IRF4-positive cells were counted in 7 HPFs per patient. There was a significantly increased number of IRF4-expressing cells in both CD and UC patients as compared with control patients. **P < 0.01. (C) Quantitative assessment of IRF4 and IL-6 mRNA in the lamina propria. IRF4 and IL-6 mRNA levels in mucosal biopsies were determined by quantitative PCR. A total of 16 IBD patients were analyzed. Values for IRF4 and IL-6 were strongly correlated (r = 0.81) in IBD. (D) Immunofluorescence double staining for IRF4 and CD3. Double-staining analysis was performed (green, IRF4-positive cells; red, CD3-positive cells). Original magnification, ×400 (upper panels); ×1000 (lower panels). Cells coexpressing IRF4 and CD3 appeared yellow (arrow). Staining analysis revealed that a large number of IRF4-positive cells coexpress CD3 on their surface. (E) Immunofluorescence double staining for IRF4 and CD4, CD8, and CD11c. Cells were stained using anti-IRF4 antibodies, and additional surface staining was performed using antibodies against either CD11c, CD8, or CD4. The number of positive cells was analyzed in 7 HPFs per patient (n = 6). CD11c, CD8, and CD4 single-positive cells and the number of double-positive cells were counted. Data represent mean values ± SD.