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The L-Arginine Transporter Solute Carrier Family 7 Member 2 Mediates the Immunopathogenesis of Attaching and Effacing Bacteria.

ABSTRACT: Solute carrier family 7 member 2 (SLC7A2) is an inducible transporter of the semi-essential amino acid L-arginine (L-Arg), which has been implicated in immune responses to pathogens. We assessed the role of SLC7A2 in murine infection with Citrobacter rodentium, an attaching and effacing enteric pathogen that causes colitis. Induction of SLC7A2 was upregulated in colitis tissues, and localized predominantly to colonic epithelial cells. Compared to wild-type mice, Slc7a2-/-mice infected with C. rodentium had improved survival and decreased weight loss, colon weight, and histologic injury; this was associated with decreased colonic macrophages, dendritic cells, granulocytes, and Th1 and Th17 cells. In infected Slc7a2-/-mice, there were decreased levels of the proinflammatory cytokines G-CSF, TNF-?, IL-1?, IL-1?, and the chemokines CXCL1, CCL2, CCL3, CCL4, CXCL2, and CCL5. In bone marrow chimeras, the recipient genotype drove the colitis phenotype, indicative of the importance of epithelial, rather than myeloid SLC7A2. Mice lacking Slc7a2 exhibited reduced adherence of C. rodentium to the colonic epithelium and decreased expression of Talin-1, a focal adhesion protein involved in the attachment of the bacterium. The importance of SLC7A2 and Talin-1 in the intimate attachment of C. rodentium and induction of inflammatory response was confirmed in vitro, using conditionally-immortalized young adult mouse colon (YAMC) cells with shRNA knockdown of Slc7a2 or Tln1. Inhibition of L-Arg uptake with the competitive inhibitor, L-lysine (L-Lys), also prevented attachment of C. rodentium and chemokine expression. L-Lys and siRNA knockdown confirmed the role of L-Arg and SLC7A2 in human Caco-2 cells co-cultured with enteropathogenic Escherichia coli. Overexpression of SLC7A2 in human embryonic kidney cells increased bacterial adherence and chemokine expression. Taken together, our data indicate that C. rodentium enhances its own pathogenicity by inducing the expression of SLC7A2 to favor its attachment to the epithelium and thus create its ecological niche.

SUBMITTER: Singh K

PROVIDER: S-EPMC5081186 | biostudies-literature | 2016 Oct

REPOSITORIES: biostudies-literature

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The L-Arginine Transporter Solute Carrier Family 7 Member 2 Mediates the Immunopathogenesis of Attaching and Effacing Bacteria.

Singh Kshipra K Al-Greene Nicole T NT Verriere Thomas G TG Coburn Lori A LA Asim Mohammad M Barry Daniel P DP Allaman Margaret M MM Hardbower Dana M DM Delgado Alberto G AG Piazuelo M Blanca MB Vallance Bruce A BA Gobert Alain P AP Wilson Keith T KT

PLoS pathogens 20161026 10

Solute carrier family 7 member 2 (SLC7A2) is an inducible transporter of the semi-essential amino acid L-arginine (L-Arg), which has been implicated in immune responses to pathogens. We assessed the role of SLC7A2 in murine infection with Citrobacter rodentium, an attaching and effacing enteric pathogen that causes colitis. Induction of SLC7A2 was upregulated in colitis tissues, and localized predominantly to colonic epithelial cells. Compared to wild-type mice, Slc7a2-/-mice infected with C. ro ...[more]

PMID: 27783672

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Project description:BACKGROUND:One aspect of smoking and lung cancer that has not been closely examined, is that regarding genes that may predispose to tobacco dependence. Smoking and mental illness are tightly linked, apparently the result of smokers using cigarettes to self-medicate for mental problems. The gene for solute carrier family 18 member A1 (vesicular monoamine transporter; SLC18A1) is of particular interest in this regard because of its association with schizophrenia, autism and bipolar illness as well as with cancer. In the current study, the relationship of SLC18A1 expression with smoking and lung cancer was analyzed. MATERIALS AND METHODS:The association between smoking, SLC18A1 expression and overall survival in the lung cancer dataset in The Cancer Genome Atlas was evaluated using the Genomic Data Commons Data Portal (https://portal.gdc.cancer.gov), as well as CbioPortal for Cancer Genomics (http://www.cbioportal.org) and the University of California Santa Cruz Xena browser (https://xenabrowser.net). RESULTS:Increased expression of SLC18A1 was found to be associated with a significantly increased survival in patients with adenocarcinoma (p=0.0058), but not those with squamous carcinoma (p=0.96). Lifelong never-smokers had the highest SLC18A1 expression. In the Pan Cancer Atlas, increased expression of SLC18A1 places such a tumor in group C5, among immunologically-quiet tumors. CONCLUSION:Most never-smokers with lung cancer do not respond to immune checkpoint inhibitors (ICIs). But for unknown reasons, a small proportion do show clinical benefit from the ICI pembrolizumab. Because of the good response of this group, it may be worthwhile assessing their SLC18A1 expression pre-treatment as a marker for potential clinical benefit. If SLC18A1 expression is low, a never-smoker may respond well to ICIs. High levels of expression would indicate a C5 tumor less likely to respond to ICIs. SLC18A1 might complement other biomarkers currently under study in relation to programmed cell death protein 1/programmed cell death protein ligand 1 inhibition.

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Dataset Information

The L-Arginine Transporter Solute Carrier Family 7 Member 2 Mediates the Immunopathogenesis of Attaching and Effacing Bacteria.

Publications

The L-Arginine Transporter Solute Carrier Family 7 Member 2 Mediates the Immunopathogenesis of Attaching and Effacing Bacteria.

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