Mononuclear phagocytes in intestinal homeostasis and inflammation
<p>Changes to the composition and function of the gut mononuclear phagocyte (MNP) compartment are associated with the development of intestinal inflammation. Much work has focused on the role of MNPs in gut-associated lymphoid tissue in maintaining homeostasis, however little is known regardin...
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| Eará dahkkit: | |
| Materiálatiipa: | Oahppočájánas |
| Giella: | English |
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2015
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| Fáttát: |
| _version_ | 1826300837902680064 |
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| author | Mathisen, S |
| author2 | Powrie, F |
| author_facet | Powrie, F Mathisen, S |
| author_sort | Mathisen, S |
| collection | OXFORD |
| description | <p>Changes to the composition and function of the gut mononuclear phagocyte (MNP) compartment are associated with the development of intestinal inflammation. Much work has focused on the role of MNPs in gut-associated lymphoid tissue in maintaining homeostasis, however little is known regarding the roles of MNPs during colitis. We have investigated MNPs in the large intestinal lamina propria during the steady state and inflammation. One of our primary aims was to determine the contribution of MNP subsets to intestinal pathology. For our studies of inflammation, we focused mainly on the <em>Helicobacter hepaticus</em> infection &plus; anti-IL-10R model, which induces inflammation of the colon and caecum (typhlocolitis). We defined the composition of the MNP compartment alongside intestinal pathology scores throughout <em>Hh</em> &plus; anti-IL-10R typhlocolitis. Peak pathology, 2-3 weeks after induction of colitis, coincided with peak frequencies of CX<sub>3</sub>CR1<sup>int</sup> Ly6C<sup>&plus;</sup> MNPs. Having observed the accumulation of CX<sub>3</sub>CR1<sup>int</sup> CD64<sup>&plus;</sup> monocyte/macrophage MNPs in the inflamed lamina propria, we conducted comparative whole genome microarray analysis of these cells isolated from the large intestine three weeks after <em>Hh</em> &plus; anti-IL-10R treatment. CX<sub>3</sub>CR1<sup>int</sup> CD64<sup>&plus;</sup> MNPs selectively expressed a variety of pro- and anti-inflammatory genes, including a number of genes which individually can both promote and negatively regulate inflammation. IL-23 is essential for <em>Hh</em> &plus; anti-IL-10R-induced intestinal pathology. We investigated the role of MNPs as a source of IL-23 which drives <em>Hh</em> &plus; anti-IL-10R colitis. Unexpectedly, our results indicate that normally hyporesponsive CX<sub>3</sub>CR1<sup>hi</sup> macrophages may act as the initial source of IL-23, which induces development of colitis. Recruitment of Ly6C<sup>&plus;</sup> MHCII<sup>&plus;</sup> MNPs to the lamina propria was IL-23-dependent, and these cells also expressed IL-23, which may establish a positive feedback loop of immune cell recruitment, activation and IL-23 production. Finally, we also examined how MNPs might be recruited to the colonic lamina propria during inflammation. Our studies support the conclusion that CCR6 is not required for accumulation of monocyte-derived populations in the inflamed intestine. We cannot rule out a role for CCR2, however preliminary data from the <em>Hh</em> &plus; anti-IL-10R colitis model suggest a potential role for CCR1 or its close relation CCRL2. Such pathways could represent new therapeutic targets in inflammatory bowel disease.</p> |
| first_indexed | 2024-03-07T05:23:13Z |
| format | Thesis |
| id | oxford-uuid:dfa5b8b5-668f-45f8-8a3b-bf18a7b0703a |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T05:23:13Z |
| publishDate | 2015 |
| record_format | dspace |
| spelling | oxford-uuid:dfa5b8b5-668f-45f8-8a3b-bf18a7b0703a2022-03-27T09:40:57ZMononuclear phagocytes in intestinal homeostasis and inflammationThesishttp://purl.org/coar/resource_type/c_db06uuid:dfa5b8b5-668f-45f8-8a3b-bf18a7b0703aMucosal ImmunologyEnglishORA Deposit2015Mathisen, SPowrie, FUdalova, ITaylor, P<p>Changes to the composition and function of the gut mononuclear phagocyte (MNP) compartment are associated with the development of intestinal inflammation. Much work has focused on the role of MNPs in gut-associated lymphoid tissue in maintaining homeostasis, however little is known regarding the roles of MNPs during colitis. We have investigated MNPs in the large intestinal lamina propria during the steady state and inflammation. One of our primary aims was to determine the contribution of MNP subsets to intestinal pathology. For our studies of inflammation, we focused mainly on the <em>Helicobacter hepaticus</em> infection &plus; anti-IL-10R model, which induces inflammation of the colon and caecum (typhlocolitis). We defined the composition of the MNP compartment alongside intestinal pathology scores throughout <em>Hh</em> &plus; anti-IL-10R typhlocolitis. Peak pathology, 2-3 weeks after induction of colitis, coincided with peak frequencies of CX<sub>3</sub>CR1<sup>int</sup> Ly6C<sup>&plus;</sup> MNPs. Having observed the accumulation of CX<sub>3</sub>CR1<sup>int</sup> CD64<sup>&plus;</sup> monocyte/macrophage MNPs in the inflamed lamina propria, we conducted comparative whole genome microarray analysis of these cells isolated from the large intestine three weeks after <em>Hh</em> &plus; anti-IL-10R treatment. CX<sub>3</sub>CR1<sup>int</sup> CD64<sup>&plus;</sup> MNPs selectively expressed a variety of pro- and anti-inflammatory genes, including a number of genes which individually can both promote and negatively regulate inflammation. IL-23 is essential for <em>Hh</em> &plus; anti-IL-10R-induced intestinal pathology. We investigated the role of MNPs as a source of IL-23 which drives <em>Hh</em> &plus; anti-IL-10R colitis. Unexpectedly, our results indicate that normally hyporesponsive CX<sub>3</sub>CR1<sup>hi</sup> macrophages may act as the initial source of IL-23, which induces development of colitis. Recruitment of Ly6C<sup>&plus;</sup> MHCII<sup>&plus;</sup> MNPs to the lamina propria was IL-23-dependent, and these cells also expressed IL-23, which may establish a positive feedback loop of immune cell recruitment, activation and IL-23 production. Finally, we also examined how MNPs might be recruited to the colonic lamina propria during inflammation. Our studies support the conclusion that CCR6 is not required for accumulation of monocyte-derived populations in the inflamed intestine. We cannot rule out a role for CCR2, however preliminary data from the <em>Hh</em> &plus; anti-IL-10R colitis model suggest a potential role for CCR1 or its close relation CCRL2. Such pathways could represent new therapeutic targets in inflammatory bowel disease.</p> |
| spellingShingle | Mucosal Immunology Mathisen, S Mononuclear phagocytes in intestinal homeostasis and inflammation |
| title | Mononuclear phagocytes in intestinal homeostasis and inflammation |
| title_full | Mononuclear phagocytes in intestinal homeostasis and inflammation |
| title_fullStr | Mononuclear phagocytes in intestinal homeostasis and inflammation |
| title_full_unstemmed | Mononuclear phagocytes in intestinal homeostasis and inflammation |
| title_short | Mononuclear phagocytes in intestinal homeostasis and inflammation |
| title_sort | mononuclear phagocytes in intestinal homeostasis and inflammation |
| topic | Mucosal Immunology |
| work_keys_str_mv | AT mathisens mononuclearphagocytesinintestinalhomeostasisandinflammation |