Interleukin-23 restrains regulatory T cell activity to drive T cell-dependent colitis - PubMed (original) (raw)

Interleukin-23 restrains regulatory T cell activity to drive T cell-dependent colitis

Ana Izcue et al. Immunity. 2008 Apr.

Abstract

Interleukin-23 (IL-23) is an inflammatory cytokine that plays a key role in the pathogenesis of several autoimmune and inflammatory diseases. It orchestrates innate and T cell-mediated inflammatory pathways and can promote T helper 17 (Th17) cell responses. Utilizing a T cell transfer model, we showed that IL-23-dependent colitis did not require IL-17 secretion by T cells. Furthermore, IL-23-independent intestinal inflammation could develop if immunosuppressive pathways were reduced. The frequency of naive T cell-derived Foxp3+ cells in the colon increased in the absence of IL-23, indicating a role for IL-23 in controlling regulatory T cell induction. Foxp3-deficient T cells induced colitis when transferred into recipients lacking IL-23p19, showing that IL-23 was not essential for intestinal inflammation in the absence of Foxp3. Taken together, our data indicate that overriding immunosuppressive pathways is an important function of IL-23 in the intestine and could influence not only Th17 cell activity but also other types of immune responses.

PubMed Disclaimer

Figures

Figure 1

Figure 1

T Cell-Derived IL-17 Is Not Essential for Colitis (A) Transfer of Il17a−/− CD4+CD45RBhi T cells into Rag1−/− mice. Left: colitis scores for recipients transferred with wild-type or IL-17-deficient CD4+CD45RBhi T cells. Each point represents an individual mouse. Data are representative of four independent experiments; graph shows pooled data from two independent experiments. Center and right: Percentage of IL-17+ (center) or IFNγ+ (right) cells among CD4+ cells isolated from the colonic lamina propria from the mice analyzed left. (B) Characterization of Th17 and Th1 cell responses in the absence of IL-23. Amounts of IFN-γ (left) and IL-17 (center) in colon homogenates of Rag1−/− or Il23a−/−Rag1−/− mice transferred with wild-type naive T cells. Right: Amounts of RORγt mRNA in colon homogenate. Values are normalized to CD3γ expression. Data show mean + SEM of between five and ten mice from two independent experiments. ∗, p < 0.05; ∗∗∗, p < 0.001.

Figure 2

Figure 2

Reduction of Regulatory Pathways Increases Colitis in Il23a−/−Rag1−/− Mice Transferred with Naive T Cells (A) Blockade of the IL-10 pathway after transfer of CD4+CD45RBhi T cells into Il23a−/−Rag1−/− mice. Left: Colitis scores for control untreated and anti-IL-10R-treated recipients. Each point represents an individual mouse. Right: Concentration of proinflammatory cytokines (mean + SEM) in colon homogenates from these mice. (B) Blockade of TGF-β after transfer of CD4+CD45RBhi T cells into Il23a−/−Rag1−/− mice. Left: Colitis scores for control untreated and anti-TGF-β treated recipients. Each point represents an individual mouse. Right: Representative microphotographs of colonic sections from either control untreated recipients (score 3) or recipients treated with blocking TGF-β antibody (score 6). The scale bars represent 200 μm. Data are pooled from two independent experiments. ∗, p < 0.05; ∗∗, p < 0.01.

Figure 3

Figure 3

Absence of TGF-β Signaling in T Cells Increases Intestinal Inflammation in Il23a−/−Rag1−/− Mice (A) Colitis score of Il23a−/−Rag1−/− mice transferred with wild-type (WT) or dnTGFβRII (DN) naive T cells. Each point represents an individual mouse. Below: Representative microphotographs of colonic sections from Il23a−/−Rag1−/− mice transferred with WT (score 2) or DN CD4+CD45RBhi T cells (score 5). The scale bars represent 200 μm. (B) IL-17 and IFN-γ production in Il23a−/−Rag1−/− mice transferred with wild-type (WT) or dnTGFβRII (DN) naive T cells. The figure shows representative FACS plots of IL-17 and IFN-γ production by MLN lymphocytes gated on CD4+ cells and the concentrations of IL-17 and IFN-γ (mean + SEM) in the colon of transferred Il23a−/−Rag1−/− mice. (C) Foxp3 expression in CD4+ cells after transfer. Left: Representative FACS plots showing Foxp3 frequency in MLN from transferred Il23a−/−Rag1−/− mice. Plots are gated on CD4+ TCRβ+ cells. Right: Percentage of Foxp3+ among MLN CD4+ T cells of transferred Il23a−/−Rag1−/−. Each point represents an individual mouse. Data are pooled from three independent experiments. ∗, p < 0.05; ∗∗, p < 0.01; ∗∗∗, p < 0.001.

Figure 4

Figure 4

CD45RBhi-Derived Foxp3+ Cells Are Increased in the Colon after Naive T Cell Transfer into Il23a−/−Rag1−/− Mice (A) Frequency of Foxp3+ cells among CD4+ T cells from spleen, MLN, and colonic LPL from IL-23-deficient or -sufficient Rag1−/− recipients transferred with CD4+ CD25− CD45RBhi naive T cells. Each point represents an individual mouse; data are pooled from two independent experiments. (B) Design of the congenic-transfer experiment. A mixture of 99% sorted CD45.1+ CD4+ CD25− CD45RBhi naive T cells and 1% CD45.2+ CD4+ CD25+ CD45RBlow regulatory T cells was injected into Rag1−/− recipients. FACS plots show representative Foxp3 staining of sorted naive (left) and regulatory (right) populations, gated on CD4+ cells. (C) Approximately 2 months after transfer, cells from spleen, MLN, and colonic LP were stained for Foxp3 and the congenic marker CD45.2. Left: Representative FACS plot showing Foxp3 versus CD45.2 expression in the spleen of transferred Il23a−/−Rag1−/−. The plot is gated on CD3+ CD4+ cells. Right: Percentage of CD45.2+ Foxp3+ cells in the CD3+ CD4+ population in the spleen, MLN, and LP of transferred IL-23-sufficient or -deficient Rag1−/− recipients. Each point represents an individual mouse. (D) Percentage of CD45.2− Foxp3+ cells in the CD3+ CD4+ population of the mice analyzed in (C). ∗, p < 0.05; ∗∗, p < 0.01; ∗∗∗, p < 0.001; ns, not significant.

Figure 5

Figure 5

Foxp3-Deficient Naive T Cells Induce Colitis in Il23a−/−Rag1−/− Mice (A) Colitis in mice transferred with Foxp3-deficient naive T cells. Left: Colitis score of Rag1−/− (circles) or Il23a−/−Rag1−/− (triangles) transferred with wild-type or Foxp3-deficient naive T cells. Each point represents an individual mouse. Right: Representative microphotographs of colonic sections from Rag1−/− mice transferred with wild-type (score 8) or Foxp3−/− naive T cells (score 10) or from Il23a−/−Rag1−/− mice transferred with wild-type (score 4) or Foxp3−/− naive T cells (score 9). The scale bars represent 200 μm. ∗∗∗, p < 0.001. (B) Left: Percentage of IL-17-secreting cells in the CD4+ population from spleen, MLN, and colon of Il23a−/−Rag1−/− mice transferred with wild-type or Foxp3−/− naive T cells. Each point represents an individual mouse. Right: Amounts of IL-17 in colon homogenate from Il23a−/−Rag1−/− mice transferred with wild-type or Foxp3−/− naive T cells. Data show the mean + SEM of nine or ten mice. Differences were not statistically significant. Data are pooled from two independent experiments.

Figure 6

Figure 6

Cytokine Expression in Inflamed Colons from Il23a−/−Rag1−/− Mice (A) Foxp3 expression after culture of CD4+CD45RBhi T cells with TGF-β, IL-23, and/or IL-21. Left: Representative FACS plots. Cells are gated on forward and side scatter to exclude dead cells. Right: Percentage of Foxp3+ cells in the CD4+ population. Data show mean + SEM of three replicates and are representative of three independent experiments. ns, not significant. (B) Relative mRNA expression of IL-6, IL-21, IL-27p28, and EBI3 in colon homogenates after naive T cell transfer with wild-type (empty columns) or dnTGFβRII or Foxp3−/− CD4+ T cells (filled columns). Data from mice transferred with dnTGFβRII or Foxp3−/− T cells were pooled because they yielded similar values. Data were normalized to HPRT for each sample. The average value for Il23a−/−Rag1−/− mice transferred with wild-type T cells (noninflamed) was set as one. Data show mean + SEM of between seven and 11 mice per group. ∗, p < 0.05; ∗∗, p < 0.01; ∗∗∗, p < 0.001; ns, not significant. (C) Amounts of proinflammatory cytokines in colon homogenates of Rag1−/− or Il23a−/−Rag1−/− transferred with Foxp3−/− naive T cells. Data show mean + SEM of between five and ten mice from two independent experiments. None of the differences were significant.

Similar articles

Cited by

References

    1. Becker C., Dornhoff H., Neufert C., Fantini M.C., Wirtz S., Huebner S., Nikolaev A., Lehr H.A., Murphy A.J., Valenzuela D.M. Cutting edge: IL-23 cross-regulates IL-12 production in T cell-dependent experimental colitis. J. Immunol. 2006;177:2760–2764. - PubMed
    1. Bettelli E., Carrier Y., Gao W., Korn T., Strom T.B., Oukka M., Weiner H.L., Kuchroo V.K. Reciprocal developmental pathways for the generation of pathogenic effector TH17 and regulatory T cells. Nature. 2006;441:235–238. - PubMed
    1. Chen W., Jin W., Hardegen N., Lei K.J., Li L., Marinos N., McGrady G., Wahl S.M. Conversion of peripheral CD4+CD25- naive T cells to CD4+CD25+ regulatory T cells by TGF-beta induction of transcription factor Foxp3. J. Exp. Med. 2003;198:1875–1886. - PMC - PubMed
    1. Cobrin G.M., Abreu M.T. Defects in mucosal immunity leading to Crohn's disease. Immunol. Rev. 2005;206:277–295. - PubMed
    1. Coombes J.L., Siddiqui K.R., Arancibia-Carcamo C.V., Hall J., Sun C.M., Belkaid Y., Powrie F. A functionally specialized population of mucosal CD103+ DCs induces Foxp3+ regulatory T cells via a TGF-{beta}- and retinoic acid-dependent mechanism. J. Exp. Med. 2007;204:1757–1764. - PMC - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources