title: Intestinal intraepithelial lymphocyte-enterocyte crosstalk regulates production of bactericidal angiogenin 4 by Paneth cells upon microbial challenge.
abstract: Antimicrobial proteins influence intestinal microbial ecology and limit proliferation of pathogens, yet the regulation of their expression has only been partially elucidated. Here, we have identified a putative pathway involving epithelial cells and intestinal intraepithelial lymphocytes (iIELs) that leads to antimicrobial protein (AMP) production by Paneth cells. Mice lacking γδ iIELs (TCRδ(-/-)) express significantly reduced levels of the AMP angiogenin 4 (Ang4). These mice were also unable to up-regulate Ang4 production following oral challenge by Salmonella, leading to higher levels of mucosal invasion compared to their wild type counterparts during the first 2 hours post-challenge. The transfer of γδ iIELs from wild type (WT) mice to TCRδ(-/-) mice restored Ang4 production and Salmonella invasion levels were reduced to those obtained in WT mice. The ability to restore Ang4 production in TCRδ(-/-) mice was shown to be restricted to γδ iIELs expressing Vγ7-encoded TCRs. Using a novel intestinal crypt co-culture system we identified a putative pathway of Ang4 production initiated by exposure to Salmonella, intestinal commensals or microbial antigens that induced intestinal epithelial cells to produce cytokines including IL‑23 in a TLR-mediated manner. Exposure of TCR-Vγ7(+) γδ iIELs to IL-23 promoted IL‑22 production, which triggered Paneth cells to secrete Ang4. These findings identify a novel role for γδ iIELs in mucosal defence through sensing immediate epithelial cell cytokine responses and influencing AMP production. This in turn can contribute to the maintenance of intestinal microbial homeostasis and epithelial barrier function, and limit pathogen invasion.
authors.affiliation: Gut Health and Food Safety, Institute of Food Research, Norwich, United Kingdom ; Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom ; Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom.
authors.forename: Catherine R
authors.initials: CR
authors.lastname: Walker
authors.affiliation: Gut Health and Food Safety, Institute of Food Research, Norwich, United Kingdom.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Hautefort
authors.affiliation: Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom ; Centre for Immunology and Infection, University of York, York, United Kingdom.
authors.forename: Jane E
authors.initials: JE
authors.lastname: Dalton
authors.affiliation: Gut Health and Food Safety, Institute of Food Research, Norwich, United Kingdom.
authors.forename: Karin
authors.initials: K
authors.lastname: Overweg
authors.affiliation: Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom ; Pediatric Surgery, Children's Hospital of Pittsburgh, UPMC, Pittsburgh, Pennsylvania, United States of America.
authors.forename: Charlotte E
authors.initials: CE
authors.lastname: Egan
authors.affiliation: Gut Health and Food Safety, Institute of Food Research, Norwich, United Kingdom.
authors.forename: Roy J
authors.initials: RJ
authors.lastname: Bongaerts
authors.affiliation: Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom ; Leeds Institute of Cancer & Pathology, Wellcome Trust Brenner Building, St James's University Hospital, Leeds, United Kingdom.
authors.forename: Darren J
authors.initials: DJ
authors.lastname: Newton
authors.affiliation: Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom ; Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom.
authors.forename: Sheena M
authors.initials: SM
authors.lastname: Cruickshank
authors.affiliation: Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom ; Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Andrew
authors.affiliation: Gut Health and Food Safety, Institute of Food Research, Norwich, United Kingdom ; Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom ; Norwich Medical School, University of East Anglia, Norwich, United Kingdom.
authors.forename: Simon R
authors.initials: SR
authors.lastname: Carding
mesh_terms: D000818:Animals; D002450:Cell Communication; D002460:Cell Line; D020895:Enterocytes / Q000378:metabolism*; D053759:Interleukin-23 / Q000096:biosynthesis; D007378:Interleukins / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000276:immunology* / Q000378:metabolism* / Q000382:microbiology; D008214:Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D019879:Paneth Cells / Q000378:metabolism*; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000378:metabolism; D012259:Ribonuclease, Pancreatic / Q000096:biosynthesis*; D012475:Salmonella / Q000276:immunology; D013312:Stress, Physiological; D000097043:Interleukin-22
chemical_list: D053759:Interleukin-23; D007378:Interleukins; D016692:Receptors, Antigen, T-Cell, gamma-delta; D012259:Ribonuclease, Pancreatic; D000097043:Interleukin-22; C519253:Ang4 protein, mouse