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Intestinal macrophages arising from CCR2(+) monocytes control pathogen infection by activating innate lymphoid cells.

Seo SU, Kuffa P, Kitamoto S, Nagao-Kitamoto H, Rousseau J, Kim YG, Núñez G, Kamada N - Nat Commun (2015)

Bottom Line: Unlike resident intestinal MPs, de novo differentiated MPs are phenotypically pro-inflammatory and produce robust amounts of IL-1β (interleukin-1β) through the non-canonical caspase-11 inflammasome.Intestinal MPs from infected mice elicit the activation of RORγt(+) group 3 innate lymphoid cells (ILC3) in an IL-1β-dependent manner.Deletion of IL-1β in blood monocytes blunts the production of IL-22 by ILC3 and increases the susceptibility to infection.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, 1500 E Medical Center Dr Ann Arbor, Michigan 48109, USA.

ABSTRACT
Monocytes play a crucial role in antimicrobial host defence, but the mechanisms by which they protect the host during intestinal infection remains poorly understood. Here we show that depletion of CCR2(+) monocytes results in impaired clearance of the intestinal pathogen Citrobacter rodentium. After infection, the de novo recruited CCR2(+) monocytes give rise to CD11c(+)CD11b(+)F4/80(+)CD103(-) intestinal macrophages (MPs) within the lamina propria. Unlike resident intestinal MPs, de novo differentiated MPs are phenotypically pro-inflammatory and produce robust amounts of IL-1β (interleukin-1β) through the non-canonical caspase-11 inflammasome. Intestinal MPs from infected mice elicit the activation of RORγt(+) group 3 innate lymphoid cells (ILC3) in an IL-1β-dependent manner. Deletion of IL-1β in blood monocytes blunts the production of IL-22 by ILC3 and increases the susceptibility to infection. Collectively, these studies highlight a critical role of de novo differentiated monocyte-derived intestinal MPs in ILC3-mediated host defence against intestinal infection.

No MeSH data available.


Related in: MedlinePlus

Recruited monocytes give rise to intestinal CD115hiCD11chi CCR2− macrophages during infection.(a) Peripheral blood and colonic LP cells were isolated from CD115GFP and CD115GFPCCR2CFP mice. Analysis of CD45+CD11b+Ly6Chi monocytes in peripheral blood and CD45+MHC-II+CD115GFP cells in colonic LP. (b) CD45+MHC-II+ colonic mononuclear phagocytes from CD115GFP mice were further analysed by flow cytometry. (c) CD115GFP and CD115GFPCCR2CFP-DTR mice were infected with C. rodentium and DT (10 ng g−1 body weight) was injected on days 5 and 7. LPMC were isolated on day 8 post infection and CD45+MHC-II+Gr-1− colonic mononuclear phagocytes were analysed. (d) Ccr2−/− mice were infected with C. rodentium. On day 4 post infection, CD11b+Ly6Chi BM monocytes were isolated from CD115GFP mice and transferred into Ccr2−/− recipient mice. The presence of GFP+ cells in the colonic LP on days 7 and 14 post C. rodentium infection (days 3 and 10 post monocyte transfer) was assessed (e). (f) The surface marker profile of purified BM monocytes (preinfection) and monocytes recovered from the colonic LP on day 7 post C. rodentium infection (day 3 post monocyte transfer). Results are representative of at least two independent experiments.
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f2: Recruited monocytes give rise to intestinal CD115hiCD11chi CCR2− macrophages during infection.(a) Peripheral blood and colonic LP cells were isolated from CD115GFP and CD115GFPCCR2CFP mice. Analysis of CD45+CD11b+Ly6Chi monocytes in peripheral blood and CD45+MHC-II+CD115GFP cells in colonic LP. (b) CD45+MHC-II+ colonic mononuclear phagocytes from CD115GFP mice were further analysed by flow cytometry. (c) CD115GFP and CD115GFPCCR2CFP-DTR mice were infected with C. rodentium and DT (10 ng g−1 body weight) was injected on days 5 and 7. LPMC were isolated on day 8 post infection and CD45+MHC-II+Gr-1− colonic mononuclear phagocytes were analysed. (d) Ccr2−/− mice were infected with C. rodentium. On day 4 post infection, CD11b+Ly6Chi BM monocytes were isolated from CD115GFP mice and transferred into Ccr2−/− recipient mice. The presence of GFP+ cells in the colonic LP on days 7 and 14 post C. rodentium infection (days 3 and 10 post monocyte transfer) was assessed (e). (f) The surface marker profile of purified BM monocytes (preinfection) and monocytes recovered from the colonic LP on day 7 post C. rodentium infection (day 3 post monocyte transfer). Results are representative of at least two independent experiments.

Mentions: CCR2+ monocytes in peripheral blood express Ly6C and CSF-1R (also known as the macrophage colony-stimulating factor (M-CSF) receptor or CD115)2324. Although certain subsets of LP mononuclear phagocytes arise from CCR2+Ly6Chi blood monocytes, these monocyte-derived LP mononuclear phagocytes do not express CCR2 in the intestine2324. Consistent with previous reports25, Ly6Chi monocytes in peripheral blood expressed both CCR2 and CD115 (Fig. 2a). In contrast, CD115+ cells in the intestinal LP did not express CCR2 (Fig. 2a), suggesting that CCR2 is downregulated in the intestinal LP. We therefore used CD115 as a marker of monocytes and monocyte-derived mononuclear phagocytes in the intestine instead of CCR2 and used CD115-GFP reporter mice to analyse CCR2+ monocyte-derived mononuclear phagocytes subsets26. To characterize CD115+ and CD115− mononuclear phagocyte subsets in the intestinal LP, total mononuclear cells were isolated from the intestinal LP and CD45+MHC-II+ mononuclear phagocytes were further classified into four subsets based on the expression of CD11b, CD11c, F4/80 and CD103 (Fig. 2b). Consistent with previous results, two subsets of monocyte-derived mononuclear phagocytes (CD11b+CD11c+F4/80+CD103−, referred to as MP subset 1 (MP1) and CD11b+CD11c-F4/80+CD103−, referred to as MP subset 2 (MP2)) expressed the monocyte-derived cell marker CD115 (Fig. 2b). In contrast, the DC subsets, which are thought to arise exclusively from a common DC progenitor, DC1 (CD11b−CD11c+F4/80−CD103+) and DC2 (CD11b+CD11c+F4/80−CD103+) lacked CD115 expression (Fig. 2b). Both MP and DC subsets in the colon lacked Gr-1 expression, suggesting that recruited monocytes downregulate the expression of Gr-1 after they reach mucosal sites (Fig. 2b). The DC2 subset (CD11chiCD11b+CD103+F4/80−) is relatively rare in the colon, while it is more abundant in the small intestine (Supplementary Fig. 2). On the basis of the expression of the monocyte marker CD115, the MP1 and MP2 subsets appear to arise from recruited monocytes. To confirm this, we depleted CCR2+ monocytes from CD115-reporter/CCR2-depleter (CD115GFPCCR2DTR-CFP) mice using DT. As expected, monocyte depletion led to a reduction of the MP1 subset (Supplementary Fig. 3). We then confirmed this result in C. rodentium-infected mice. Consistent with the results in uninfected mice, monocyte depletion affected the CD115+CD11c+ MP1 subset but did not impact on the number of MP2 and DC1 cells, suggesting that recruited monocytes preferentially give rise to the MP1 subset during infection (Fig. 2c). To further verify this, CD115-GFP+ monocytes were purified from the BM and transferred into C. rodentium-infected Ccr2−/− recipient mice on day 4 post infection (Fig. 2d). The transferred CD115-GFP+ monocyte-derived cells were found in the colonic LP on days 3 and 10 after monocyte transfer (days 7 and 14 post infection), but not in the spleen or mesenteric lymph nodes (Fig. 2e and Supplementary Fig. 4). These results indicate that monocytes preferentially migrate to the colonic LP in infected mice. Notably, while isolated monocytes expressed CD11b and Gr-1, and lacked CD11c before the transfer, the CD115-GFP+ monocytes recovered from the colonic LP expressed CD11c but downregulated Gr-1 expression (Fig. 2f), indicating that monocytes differentiate into the MP1 subset after migration to the colonic LP.


Intestinal macrophages arising from CCR2(+) monocytes control pathogen infection by activating innate lymphoid cells.

Seo SU, Kuffa P, Kitamoto S, Nagao-Kitamoto H, Rousseau J, Kim YG, Núñez G, Kamada N - Nat Commun (2015)

Recruited monocytes give rise to intestinal CD115hiCD11chi CCR2− macrophages during infection.(a) Peripheral blood and colonic LP cells were isolated from CD115GFP and CD115GFPCCR2CFP mice. Analysis of CD45+CD11b+Ly6Chi monocytes in peripheral blood and CD45+MHC-II+CD115GFP cells in colonic LP. (b) CD45+MHC-II+ colonic mononuclear phagocytes from CD115GFP mice were further analysed by flow cytometry. (c) CD115GFP and CD115GFPCCR2CFP-DTR mice were infected with C. rodentium and DT (10 ng g−1 body weight) was injected on days 5 and 7. LPMC were isolated on day 8 post infection and CD45+MHC-II+Gr-1− colonic mononuclear phagocytes were analysed. (d) Ccr2−/− mice were infected with C. rodentium. On day 4 post infection, CD11b+Ly6Chi BM monocytes were isolated from CD115GFP mice and transferred into Ccr2−/− recipient mice. The presence of GFP+ cells in the colonic LP on days 7 and 14 post C. rodentium infection (days 3 and 10 post monocyte transfer) was assessed (e). (f) The surface marker profile of purified BM monocytes (preinfection) and monocytes recovered from the colonic LP on day 7 post C. rodentium infection (day 3 post monocyte transfer). Results are representative of at least two independent experiments.
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f2: Recruited monocytes give rise to intestinal CD115hiCD11chi CCR2− macrophages during infection.(a) Peripheral blood and colonic LP cells were isolated from CD115GFP and CD115GFPCCR2CFP mice. Analysis of CD45+CD11b+Ly6Chi monocytes in peripheral blood and CD45+MHC-II+CD115GFP cells in colonic LP. (b) CD45+MHC-II+ colonic mononuclear phagocytes from CD115GFP mice were further analysed by flow cytometry. (c) CD115GFP and CD115GFPCCR2CFP-DTR mice were infected with C. rodentium and DT (10 ng g−1 body weight) was injected on days 5 and 7. LPMC were isolated on day 8 post infection and CD45+MHC-II+Gr-1− colonic mononuclear phagocytes were analysed. (d) Ccr2−/− mice were infected with C. rodentium. On day 4 post infection, CD11b+Ly6Chi BM monocytes were isolated from CD115GFP mice and transferred into Ccr2−/− recipient mice. The presence of GFP+ cells in the colonic LP on days 7 and 14 post C. rodentium infection (days 3 and 10 post monocyte transfer) was assessed (e). (f) The surface marker profile of purified BM monocytes (preinfection) and monocytes recovered from the colonic LP on day 7 post C. rodentium infection (day 3 post monocyte transfer). Results are representative of at least two independent experiments.
Mentions: CCR2+ monocytes in peripheral blood express Ly6C and CSF-1R (also known as the macrophage colony-stimulating factor (M-CSF) receptor or CD115)2324. Although certain subsets of LP mononuclear phagocytes arise from CCR2+Ly6Chi blood monocytes, these monocyte-derived LP mononuclear phagocytes do not express CCR2 in the intestine2324. Consistent with previous reports25, Ly6Chi monocytes in peripheral blood expressed both CCR2 and CD115 (Fig. 2a). In contrast, CD115+ cells in the intestinal LP did not express CCR2 (Fig. 2a), suggesting that CCR2 is downregulated in the intestinal LP. We therefore used CD115 as a marker of monocytes and monocyte-derived mononuclear phagocytes in the intestine instead of CCR2 and used CD115-GFP reporter mice to analyse CCR2+ monocyte-derived mononuclear phagocytes subsets26. To characterize CD115+ and CD115− mononuclear phagocyte subsets in the intestinal LP, total mononuclear cells were isolated from the intestinal LP and CD45+MHC-II+ mononuclear phagocytes were further classified into four subsets based on the expression of CD11b, CD11c, F4/80 and CD103 (Fig. 2b). Consistent with previous results, two subsets of monocyte-derived mononuclear phagocytes (CD11b+CD11c+F4/80+CD103−, referred to as MP subset 1 (MP1) and CD11b+CD11c-F4/80+CD103−, referred to as MP subset 2 (MP2)) expressed the monocyte-derived cell marker CD115 (Fig. 2b). In contrast, the DC subsets, which are thought to arise exclusively from a common DC progenitor, DC1 (CD11b−CD11c+F4/80−CD103+) and DC2 (CD11b+CD11c+F4/80−CD103+) lacked CD115 expression (Fig. 2b). Both MP and DC subsets in the colon lacked Gr-1 expression, suggesting that recruited monocytes downregulate the expression of Gr-1 after they reach mucosal sites (Fig. 2b). The DC2 subset (CD11chiCD11b+CD103+F4/80−) is relatively rare in the colon, while it is more abundant in the small intestine (Supplementary Fig. 2). On the basis of the expression of the monocyte marker CD115, the MP1 and MP2 subsets appear to arise from recruited monocytes. To confirm this, we depleted CCR2+ monocytes from CD115-reporter/CCR2-depleter (CD115GFPCCR2DTR-CFP) mice using DT. As expected, monocyte depletion led to a reduction of the MP1 subset (Supplementary Fig. 3). We then confirmed this result in C. rodentium-infected mice. Consistent with the results in uninfected mice, monocyte depletion affected the CD115+CD11c+ MP1 subset but did not impact on the number of MP2 and DC1 cells, suggesting that recruited monocytes preferentially give rise to the MP1 subset during infection (Fig. 2c). To further verify this, CD115-GFP+ monocytes were purified from the BM and transferred into C. rodentium-infected Ccr2−/− recipient mice on day 4 post infection (Fig. 2d). The transferred CD115-GFP+ monocyte-derived cells were found in the colonic LP on days 3 and 10 after monocyte transfer (days 7 and 14 post infection), but not in the spleen or mesenteric lymph nodes (Fig. 2e and Supplementary Fig. 4). These results indicate that monocytes preferentially migrate to the colonic LP in infected mice. Notably, while isolated monocytes expressed CD11b and Gr-1, and lacked CD11c before the transfer, the CD115-GFP+ monocytes recovered from the colonic LP expressed CD11c but downregulated Gr-1 expression (Fig. 2f), indicating that monocytes differentiate into the MP1 subset after migration to the colonic LP.

Bottom Line: Unlike resident intestinal MPs, de novo differentiated MPs are phenotypically pro-inflammatory and produce robust amounts of IL-1β (interleukin-1β) through the non-canonical caspase-11 inflammasome.Intestinal MPs from infected mice elicit the activation of RORγt(+) group 3 innate lymphoid cells (ILC3) in an IL-1β-dependent manner.Deletion of IL-1β in blood monocytes blunts the production of IL-22 by ILC3 and increases the susceptibility to infection.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, 1500 E Medical Center Dr Ann Arbor, Michigan 48109, USA.

ABSTRACT
Monocytes play a crucial role in antimicrobial host defence, but the mechanisms by which they protect the host during intestinal infection remains poorly understood. Here we show that depletion of CCR2(+) monocytes results in impaired clearance of the intestinal pathogen Citrobacter rodentium. After infection, the de novo recruited CCR2(+) monocytes give rise to CD11c(+)CD11b(+)F4/80(+)CD103(-) intestinal macrophages (MPs) within the lamina propria. Unlike resident intestinal MPs, de novo differentiated MPs are phenotypically pro-inflammatory and produce robust amounts of IL-1β (interleukin-1β) through the non-canonical caspase-11 inflammasome. Intestinal MPs from infected mice elicit the activation of RORγt(+) group 3 innate lymphoid cells (ILC3) in an IL-1β-dependent manner. Deletion of IL-1β in blood monocytes blunts the production of IL-22 by ILC3 and increases the susceptibility to infection. Collectively, these studies highlight a critical role of de novo differentiated monocyte-derived intestinal MPs in ILC3-mediated host defence against intestinal infection.

No MeSH data available.


Related in: MedlinePlus