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TLR1-induced chemokine production is critical for mucosal immunity against Yersinia enterocolitica.

Sugiura Y, Kamdar K, Khakpour S, Young G, Karpus WJ, DePaolo RW - Mucosal Immunol (2013)

Bottom Line: Intestinal epithelial cells are a central player in barrier function and also in communicating signals from invading pathogens to the underlying immune tissue.Here we demonstrate that activation of Toll-like receptor 1 (TLR1) in the epithelium leads to the upregulation of the chemokine CCL20 during oral infection with Yersinia enterocolitica.These data demonstrate a novel role for TLR1 signaling in the intestinal epithelium and demonstrate that together TLR1 and CCL20 are critical mediators of TH17 immunity through the activation and recruitment of DCs.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Sciences, Midwestern University, Downers Grove, Illinois, USA.

ABSTRACT
Our gastrointestinal tract is a portal of entry for a number of bacteria and viruses. Thus, this tissue must develop ways to induce antigen-specific T cell and antibody responses quickly. Intestinal epithelial cells are a central player in barrier function and also in communicating signals from invading pathogens to the underlying immune tissue. Here we demonstrate that activation of Toll-like receptor 1 (TLR1) in the epithelium leads to the upregulation of the chemokine CCL20 during oral infection with Yersinia enterocolitica. Further, both neutralization of CCL20 using polyclonal antibody treatment and deletion of TLR1 resulted in a defect in CCR6+ dendritic cells (DCs), which produce innate cytokines that help to induce anti-Yersinia-specific T helper 17 (TH17) cells and IgA production. These data demonstrate a novel role for TLR1 signaling in the intestinal epithelium and demonstrate that together TLR1 and CCL20 are critical mediators of TH17 immunity through the activation and recruitment of DCs.

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Toll-like receptor 1 (TLR1) and CCL20 are important for recruitment of CCR6+ CD11c+ cells to the Peyer's patch (PP) during oral Y. enterocolitica infection. Flow cytometric analysis of dendritic cell (DC) population in PP of anti-CCL20-treated (a) and TLR1−/− (b) mice. Data are representative of five individual mice pooled from two experiments. (c) Total cell number of CCR6+CD11c+ cells. (d) Bone marrow chimera's were performed by reconstituting TLR1−/− mice with wild-type (WT) hematopoietic cells (WT→TLR1−/−) and by reconstituting WT mice with TLR1−/− hematopoietic cells (TLR1−/−→WT). CCR6+ DC in the PP of the bone marrow chimera's were identified by flow cytometric analysis (left) and total cell count (right) 3 days after infection with Y. enterocolitica. Data are pooled from two independent experiments (n=3–6 mice per group). *P<0.05, **P<0.01, ***P<0.001 (Student's unpaired t-test).
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fig4: Toll-like receptor 1 (TLR1) and CCL20 are important for recruitment of CCR6+ CD11c+ cells to the Peyer's patch (PP) during oral Y. enterocolitica infection. Flow cytometric analysis of dendritic cell (DC) population in PP of anti-CCL20-treated (a) and TLR1−/− (b) mice. Data are representative of five individual mice pooled from two experiments. (c) Total cell number of CCR6+CD11c+ cells. (d) Bone marrow chimera's were performed by reconstituting TLR1−/− mice with wild-type (WT) hematopoietic cells (WT→TLR1−/−) and by reconstituting WT mice with TLR1−/− hematopoietic cells (TLR1−/−→WT). CCR6+ DC in the PP of the bone marrow chimera's were identified by flow cytometric analysis (left) and total cell count (right) 3 days after infection with Y. enterocolitica. Data are pooled from two independent experiments (n=3–6 mice per group). *P<0.05, **P<0.01, ***P<0.001 (Student's unpaired t-test).

Mentions: CCR6+ DCs have been shown to have an important role in the defense against mucosal Salmonella infection.20 These DCs are rapidly recruited to the PPs, where they are activated to prime anti-Salmonella T cells.20 To determine whether CCR6+ cells also have a role in Y. enterocolitica infection, we examined the PPs for the accumulation of CCR6+CD11c+ cells 48 h after mucosal Y. enterocolitica infection in TLR1-deficient mice and mice treated with neutralizing antibody against CCL20. Untreated wild-type mice or those receiving isotype control antibody developed an increase in CCR6+ CD11c+ cells after Yersinia infection (Figure 4a). Consistent with a role for TLR1 in CCL20 induction, mice deficient for TLR1 demonstrated a significant reduction in the frequency (Figure 4b) and total number (Figure 4c) of CCR6-expressing DCs during infection. Importantly, the defect in CCR6+ DC observed in TLR1-deficient mice looked remarkably similar to the defect observed in wild-type mice treated with neutralizing anti-CCL20 antibodies (Figure 4a–c). Analysis of CCR6 expression on B and CD4 T cells in the LP from anti-CCL20-treated or TLR1−/− mice revealed no differences (data not shown). This may be due to increases in other inflammatory chemokines induced during infection that recruit adaptive immune cells. To confirm the importance of TLR1 signaling in the IEC for CCL20 production and the recruitment of CCR6+ DC during Y. enterocolitica infection bone-marrow chimera's were performed. Lethally irradiated TLR1−/− mice reconstituted with bone marrow from wild-type littermate control mice maintain the ability to signal via TLR1 in the immune cells, but lack the ability to signal through TLR1 in the IEC. These mice were unable to produce CCL20 after Y. enterocolitica infection (data not shown) and had a significant decrease in the recruitment of CCR6+ DC compared with wild-type mice reconstituted with TLR1−/− bone marrow cells (Figure 4d). Overall, these data demonstrate that TLR1 signaling in the epithelium of the small intestine contributes to the recruitment of CCR6+ DC during infection by Y. enterocolitica.


TLR1-induced chemokine production is critical for mucosal immunity against Yersinia enterocolitica.

Sugiura Y, Kamdar K, Khakpour S, Young G, Karpus WJ, DePaolo RW - Mucosal Immunol (2013)

Toll-like receptor 1 (TLR1) and CCL20 are important for recruitment of CCR6+ CD11c+ cells to the Peyer's patch (PP) during oral Y. enterocolitica infection. Flow cytometric analysis of dendritic cell (DC) population in PP of anti-CCL20-treated (a) and TLR1−/− (b) mice. Data are representative of five individual mice pooled from two experiments. (c) Total cell number of CCR6+CD11c+ cells. (d) Bone marrow chimera's were performed by reconstituting TLR1−/− mice with wild-type (WT) hematopoietic cells (WT→TLR1−/−) and by reconstituting WT mice with TLR1−/− hematopoietic cells (TLR1−/−→WT). CCR6+ DC in the PP of the bone marrow chimera's were identified by flow cytometric analysis (left) and total cell count (right) 3 days after infection with Y. enterocolitica. Data are pooled from two independent experiments (n=3–6 mice per group). *P<0.05, **P<0.01, ***P<0.001 (Student's unpaired t-test).
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fig4: Toll-like receptor 1 (TLR1) and CCL20 are important for recruitment of CCR6+ CD11c+ cells to the Peyer's patch (PP) during oral Y. enterocolitica infection. Flow cytometric analysis of dendritic cell (DC) population in PP of anti-CCL20-treated (a) and TLR1−/− (b) mice. Data are representative of five individual mice pooled from two experiments. (c) Total cell number of CCR6+CD11c+ cells. (d) Bone marrow chimera's were performed by reconstituting TLR1−/− mice with wild-type (WT) hematopoietic cells (WT→TLR1−/−) and by reconstituting WT mice with TLR1−/− hematopoietic cells (TLR1−/−→WT). CCR6+ DC in the PP of the bone marrow chimera's were identified by flow cytometric analysis (left) and total cell count (right) 3 days after infection with Y. enterocolitica. Data are pooled from two independent experiments (n=3–6 mice per group). *P<0.05, **P<0.01, ***P<0.001 (Student's unpaired t-test).
Mentions: CCR6+ DCs have been shown to have an important role in the defense against mucosal Salmonella infection.20 These DCs are rapidly recruited to the PPs, where they are activated to prime anti-Salmonella T cells.20 To determine whether CCR6+ cells also have a role in Y. enterocolitica infection, we examined the PPs for the accumulation of CCR6+CD11c+ cells 48 h after mucosal Y. enterocolitica infection in TLR1-deficient mice and mice treated with neutralizing antibody against CCL20. Untreated wild-type mice or those receiving isotype control antibody developed an increase in CCR6+ CD11c+ cells after Yersinia infection (Figure 4a). Consistent with a role for TLR1 in CCL20 induction, mice deficient for TLR1 demonstrated a significant reduction in the frequency (Figure 4b) and total number (Figure 4c) of CCR6-expressing DCs during infection. Importantly, the defect in CCR6+ DC observed in TLR1-deficient mice looked remarkably similar to the defect observed in wild-type mice treated with neutralizing anti-CCL20 antibodies (Figure 4a–c). Analysis of CCR6 expression on B and CD4 T cells in the LP from anti-CCL20-treated or TLR1−/− mice revealed no differences (data not shown). This may be due to increases in other inflammatory chemokines induced during infection that recruit adaptive immune cells. To confirm the importance of TLR1 signaling in the IEC for CCL20 production and the recruitment of CCR6+ DC during Y. enterocolitica infection bone-marrow chimera's were performed. Lethally irradiated TLR1−/− mice reconstituted with bone marrow from wild-type littermate control mice maintain the ability to signal via TLR1 in the immune cells, but lack the ability to signal through TLR1 in the IEC. These mice were unable to produce CCL20 after Y. enterocolitica infection (data not shown) and had a significant decrease in the recruitment of CCR6+ DC compared with wild-type mice reconstituted with TLR1−/− bone marrow cells (Figure 4d). Overall, these data demonstrate that TLR1 signaling in the epithelium of the small intestine contributes to the recruitment of CCR6+ DC during infection by Y. enterocolitica.

Bottom Line: Intestinal epithelial cells are a central player in barrier function and also in communicating signals from invading pathogens to the underlying immune tissue.Here we demonstrate that activation of Toll-like receptor 1 (TLR1) in the epithelium leads to the upregulation of the chemokine CCL20 during oral infection with Yersinia enterocolitica.These data demonstrate a novel role for TLR1 signaling in the intestinal epithelium and demonstrate that together TLR1 and CCL20 are critical mediators of TH17 immunity through the activation and recruitment of DCs.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Sciences, Midwestern University, Downers Grove, Illinois, USA.

ABSTRACT
Our gastrointestinal tract is a portal of entry for a number of bacteria and viruses. Thus, this tissue must develop ways to induce antigen-specific T cell and antibody responses quickly. Intestinal epithelial cells are a central player in barrier function and also in communicating signals from invading pathogens to the underlying immune tissue. Here we demonstrate that activation of Toll-like receptor 1 (TLR1) in the epithelium leads to the upregulation of the chemokine CCL20 during oral infection with Yersinia enterocolitica. Further, both neutralization of CCL20 using polyclonal antibody treatment and deletion of TLR1 resulted in a defect in CCR6+ dendritic cells (DCs), which produce innate cytokines that help to induce anti-Yersinia-specific T helper 17 (TH17) cells and IgA production. These data demonstrate a novel role for TLR1 signaling in the intestinal epithelium and demonstrate that together TLR1 and CCL20 are critical mediators of TH17 immunity through the activation and recruitment of DCs.

Show MeSH
Related in: MedlinePlus