CRTAM Shapes the Gut Microbiota and Enhances the Severity of Infection Araceli Perez-Lopez, Sean-Paul Nuccio, Irina Ushach, Robert A. Edwards, Rachna Pahu, Steven Silva, Albert This information is current as Zlotnik and Manuela Raffatellu of October 3, 2021. J Immunol 2019; 203:532-543; Prepublished online 29 May 2019; doi: 10.4049/jimmunol.1800890 http://www.jimmunol.org/content/203/2/532 Downloaded from Supplementary http://www.jimmunol.org/content/suppl/2019/05/28/jimmunol.180089 Material 0.DCSupplemental References This article cites 60 articles, 15 of which you can access for free at: http://www.jimmunol.org/ http://www.jimmunol.org/content/203/2/532.full#ref-list-1 Why The JI? Submit online. • Rapid Reviews! 30 days* from submission to initial decision • No Triage! Every submission reviewed by practicing scientists by guest on October 3, 2021 • Fast Publication! 4 weeks from acceptance to publication *average Subscription Information about subscribing to The Journal of Immunology is online at: http://jimmunol.org/subscription Permissions Submit copyright permission requests at: http://www.aai.org/About/Publications/JI/copyright.html Email Alerts Receive free email-alerts when new articles cite this article. Sign up at: http://jimmunol.org/alerts The Journal of Immunology is published twice each month by The American Association of Immunologists, Inc., 1451 Rockville Pike, Suite 650, Rockville, MD 20852 Copyright © 2019 by The American Association of Immunologists, Inc. All rights reserved. Print ISSN: 0022-1767 Online ISSN: 1550-6606. The Journal of Immunology CRTAM Shapes the Gut Microbiota and Enhances the Severity of Infection Araceli Perez-Lopez,*,†,‡ Sean-Paul Nuccio,*,†,‡ Irina Ushach,‡,x Robert A. Edwards,{ Rachna Pahu,† Steven Silva,* Albert Zlotnik,‡,x and Manuela Raffatellu*,†,‡,‖,# Gut lymphocytes and the microbiota establish a reciprocal relationship that impacts the host immune response. Class I–restricted T cell–associated molecule (CRTAM) is a cell adhesion molecule expressed by intraepithelial T cells and is required for their retention in the gut. In this study, we show that CRTAM expression affects gut microbiota composition under homeostatic conditions. Moreover, Crtam2/2 mice infected with the intestinal pathogen Salmonella exhibit reduced Th17 responses, lower levels of inflammation, and reduced Salmonella burden, which is accompanied by expansion of other microbial taxa. Thus, CRTAM enhances susceptibility to Salmonella, likely by promoting the inflammatory response that promotes the pathogen’s growth. We also found that the gut microbiota from wild-type mice, but not from Crtam2/2 mice, induces CRTAM expression and Downloaded from Th17 responses in ex–germ-free mice during Salmonella infection. Our study demonstrates a reciprocal relationship between CRTAM expression and the gut microbiota, which ultimately impacts the host response to enteric pathogens. The Journal of Immunology, 2019, 203: 532–543. esident T cells in the gut are key orchestrators of T cells are required to develop an optimal immune response mucosal immunity. Located between epithelial cells against enteric pathogens. R (intraepithelial lymphocytes [IELs]) and in the lamina Th17 cells are an important subset of CD4+ T cells residing in http://www.jimmunol.org/ propria, these T cells are comprised of several subpopulations, the gut. These cells constitute a distinct lineage from Th1 and including CD4+ Tcells,CD8+ Tcells,gd T cells, NKT cells, and Th2 cells and are characterized by the production of IL-17A, a unique population of CD4+CD8+ T cells (1, 2). A consequence IL-17F, and IL-22, collectively known as Th17 cytokines (7). of CD4+ T cell depletion in GALT is a disruption of the gut Th17 cytokines are expressed in the intestinal mucosa in re- epithelial barrier, a scenario common among HIV-infected pa- sponse to enteric pathogens such as Salmonella and Citrobacter tients (3). As a result, HIV patients exhibit an increased sus- rodentium (8–10) and orchestrate a host response that strengthens ceptibility to bacteremia caused by intestinal pathogens such as the mucosal barrier and protects from systemic dissemination Salmonella and Campylobacter (4–6), indicating that CD4+ of these pathogens. In the mouse model of inflammatory di- by guest on October 3, 2021 arrhea, mice deficient in the IL-17A receptor exhibit higher levels of Salmonella translocation from the gut to systemic *Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, sites such as the spleen. Moreover, Th17 deficiency results in a University of California, San Diego, La Jolla, CA 92093; †Department of Microbi- reduction of neutrophil recruitment to the intestinal mucosa ology and Molecular Genetics, University of California, Irvine, Irvine, CA 92697; ‡ x during infection (10), which may explain the increased sys- Institute for Immunology, University of California, Irvine, Irvine, CA 92697; De- partment of Physiology and Biophysics, University of California, Irvine, Irvine, CA temic dissemination of Salmonella in the absence of IL-17 { 92697; Department of Pathology and Laboratory Medicine, University of California, signaling. For Citrobacter, the highly homologous IL-17A, Irvine, Irvine, CA 92697; ‖Chiba University-University of California San Diego Center for Mucosal Immunology, Allergy, and Vaccines, La Jolla, CA 92093; and IL-17F (8), and IL-17C (11) are important to reduce the #Center for Microbiome Innovation, University of California, San Diego, La Jolla, pathogen’s colonization of the colon. This reduction in colo- CA 92093 nization is mediated by IL-17A/F–induced b-defensins (8) ORCIDs: 0000-0002-5399-1958 (A.P.-L.); 0000-0002-9683-9278 (S.-P.N.); 0000- and by IL-17C/IL-22–induced proinflammatory cytokines, 0001-9145-382X (R.A.E.); 0000-0001-8529-4535 (S.S.); 0000-0003-0030- 9350 (A.Z.); 0000-0001-6487-4215 (M.R.). chemokines, and antimicrobial proteins, including calpro- tectin, lipocalin-2, RegIIIb, and RegIIIg (11). Together, these Received for publication June 27, 2018. Accepted for publication May 3, 2019. studies underscore the importance of Th17 cells in host de- Work in the Raffatellu laboratory was supported by Public Health Service Grants AI114625, AI121928, AI126277, and AI126465, by the Chiba University-University fense against gut pathogens. of California, San Diego Center for Mucosal Immunology, Allergy, and Vaccines, Homing and residency of T cells to the gut requires the expression and by the University of California, San Diego Department of Pediatrics. M.R. also of specialized chemokines, chemokine receptors, and adhesion holds an Investigator in the Pathogenesis of Infectious Disease Award from the Burroughs Wellcome Fund. A.P.-L. was partly supported by a University of Califor- molecules (reviewed in Ref. 12). For instance, entry of naive and nia Institute for Mexico and the United States El Consejo Nacional de Ciencia y effector T cells into the intestinal mucosa is mediated by integrin Tecnologı´a award and by a Mucosal Immunology Studies Team Scholar Award in Mucosal Immunity. a4b7, which binds to mucosal vascular addressin cell adhesion molecule 1 (CADM1) expressed in the lamina propria venules (13). Address correspondence and reprint requests to Prof. Manuela Raffatellu, Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of Integrin aEb7 is involved in the retention of effector and memory California, San Diego, La Jolla, CA 92093. E-mail address: [email protected] lymphocytes to the gut epithelium through its interaction with The online version of this article contains supplemental material. E-cadherin (14). In addition to the interactions described above, it Abbreviations used in this article: CADM1, cell adhesion molecule 1; CRTAM, class has been shown that the interaction between class I–restricted T cell– I–restricted T cell–associated molecule; IEL, intraepithelial lymphocyte; LPL, lam- associated molecule (CRTAM) in T cells and CADM1 (also known ina propria lymphocyte; Treg, T regulatory cell; WT, wild-type. as NECL2 and TSLC1) contributes to the residency and mainte- Copyright Ó 2019 by The American Association of Immunologists, Inc. 0022-1767/19/$37.50 nance of T cell populations in the gut mucosa (15). www.jimmunol.org/cgi/doi/10.4049/jimmunol.1800890 The Journal of Immunology 533 Located on the cell surface, CRTAM is an Ig superfamily (targeting project identification CSD67690) at the University of California, + Davis. We obtained these founder mice and performed the following ex- member that was originally identified in activated CD8 T cells and 2/2 NKT cells (hence its name, Class I restricted) (16). Further reports periments on their wild-type (WT) and Crtam littermate progeny. Male and female mice were orally gavaged with streptomycin 24 h before oral described CRTAM on NK cells (17). More recently, CRTAM has gavage with 109 CFUs of S. enterica serovar Typhimurium IR715, as been described on intraepithelial CD4+CD8a/a+ and CD4+ T cells previously described (10, 27). Fecal samples were collected at 24, 48, 72, as well as on CD8+ T cells of the intestinal mucosa (15). CADM1, and 96 h postinfection. The cecal content was collected at 96 h postin- the only CRTAM ligand described to date (17), is a cell surface fection. Fecal samples and cecal content were serially diluted and plated on appropriate antibiotic-containing lysogeny broth agar plates to deter- molecule of the nectin and NECL families that is expressed mine bacterial counts (CFUs). Spleen, mesenteric lymph nodes, Peyer + on CD8a dendritic cells, CD103 dendritic cells, epithelial cells, patches, and terminal ileum were collected, weighed, homogenized, seri- neurons, and certain tumor cells (18–21). CRTAM–CADM1 in- ally diluted, and plated on appropriate antibiotic-containing lysogeny broth teractions strengthen NK cell and CD8+ T cell effector functions agar plates to determine CFUs. All animal experiments were reviewed (17, 19, 22, 23). Moreover, it has been proposed that CRTAM is and approved by the Institutional Animal Care and Use Committees at + the University of California, Irvine and at the University of California, essential for the establishment of CD4 T cell polarization after San Diego.