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Shin WG, Park BJ, Lee SJ, Kim JG. Infection of human intestinal epithelial cells by invasive bacteria activates NF-κB and increases ICAM-1 expression through NOD1. Korean J Intern Med 2018; 33:81-90. [PMID: 28092699 PMCID: PMC5768537 DOI: 10.3904/kjim.2015.409] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 07/01/2016] [Accepted: 10/10/2016] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND/AIMS Nucleotide-binding oligomerization domain 1 (NOD1) is required for primary intestinal epithelial cells (IECs) to respond to natural mucopeptides secreted by gram-negative bacteria. Infection of human IECs with invasive bacteria up-regulates intercellular adhesion molecule-1 (ICAM-1) expression. However, the role of NOD family members in host defense has been largely unknown. The aim of this study was to determine whether there is a functional role for NOD1 in the up-regulation of ICAM-1 expression in invasive bacteria-infected IECs. METHODS ICAM-1 mRNA expression was compared between controls, Caco-2 or HT29 cells transfected with an empty vector, and IECs stably transfected with a dominant-negative (DN) NOD1. Expression was compared using qualitative reverse transcription polymerase chain reaction (RT-PCR), real-time RT-PCR, and flow cytometry after infection with enteroinvasive Escherichia coli O29:NM or Shigella flexneri. Nuclear factor kB (NF-κB) activation was determined by electrophoretic mobility shift assays. RESULTS DN NOD1 significantly inhibited the up-regulation of ICAM-1 expression in response to an enteroinvasive bacterial infection. The Caco-2 cells transfected with DN NOD1 manifested marked inhibition of NF-kB activation in response to E. coli O29:NM infection. CONCLUSIONS Signaling through NOD1 may play an essential role in neutrophil trafficking following infection with enteroinvasive bacteria.
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Affiliation(s)
- Woon Geon Shin
- Department of Internal Medicine, Hallym University College of Medicine, Seoul, Korea
| | - Bum Joon Park
- Department of Internal Medicine, Chung-Ang University College of Medicine, Seoul, Korea
| | - Sung Joong Lee
- Department of Dentistry, Seoul National University School of Dentistry, Seoul, Korea
| | - Jae Gyu Kim
- Department of Internal Medicine, Chung-Ang University College of Medicine, Seoul, Korea
- Correspondence to Jae Gyu Kim, M.D. Division of Gastroenterology, Department of Internal Medicine, Chung-Ang University Hospital, 102 Heukseok-ro, Dongjak-gu, Seoul 06973, Korea Tel: +82-2-6299-3147 Fax: +82-2-749-9150 E-mail:
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2
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Kell DB, Pretorius E. On the translocation of bacteria and their lipopolysaccharides between blood and peripheral locations in chronic, inflammatory diseases: the central roles of LPS and LPS-induced cell death. Integr Biol (Camb) 2016; 7:1339-77. [PMID: 26345428 DOI: 10.1039/c5ib00158g] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We have recently highlighted (and added to) the considerable evidence that blood can contain dormant bacteria. By definition, such bacteria may be resuscitated (and thus proliferate). This may occur under conditions that lead to or exacerbate chronic, inflammatory diseases that are normally considered to lack a microbial component. Bacterial cell wall components, such as the endotoxin lipopolysaccharide (LPS) of Gram-negative strains, are well known as potent inflammatory agents, but should normally be cleared. Thus, their continuing production and replenishment from dormant bacterial reservoirs provides an easy explanation for the continuing, low-grade inflammation (and inflammatory cytokine production) that is characteristic of many such diseases. Although experimental conditions and determinants have varied considerably between investigators, we summarise the evidence that in a great many circumstances LPS can play a central role in all of these processes, including in particular cell death processes that permit translocation between the gut, blood and other tissues. Such localised cell death processes might also contribute strongly to the specific diseases of interest. The bacterial requirement for free iron explains the strong co-existence in these diseases of iron dysregulation, LPS production, and inflammation. Overall this analysis provides an integrative picture, with significant predictive power, that is able to link these processes via the centrality of a dormant blood microbiome that can resuscitate and shed cell wall components.
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Affiliation(s)
- Douglas B Kell
- School of Chemistry and The Manchester Institute of Biotechnology, The University of Manchester, 131, Princess St, Manchester M1 7DN, Lancs, UK.
| | - Etheresia Pretorius
- Department of Physiology, Faculty of Health Sciences, University of Pretoria, Arcadia 0007, South Africa.
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3
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Keestra AM, Bäumler AJ. Detection of enteric pathogens by the nodosome. Trends Immunol 2013; 35:123-30. [PMID: 24268520 DOI: 10.1016/j.it.2013.10.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 10/23/2013] [Accepted: 10/24/2013] [Indexed: 01/31/2023]
Abstract
Nucleotide-binding oligomerization domain protein (NOD)1 and NOD2 participate in signaling pathways that detect pathogen-induced processes, such as the presence of peptidoglycan fragments in the host cell cytosol, as danger signals. Recent work suggests that peptidoglycan fragments activate NOD1 indirectly, through activation of the small Rho GTPase Ras-related C3 botulinum toxin substrate 1 (RAC1). Excessive activation of small Rho GTPases by virulence factors of enteric pathogens also triggers the NOD1 signaling pathway. Many enteric pathogens use virulence factors that alter the activation state of small Rho GTPases, thereby manipulating the host cell cytoskeleton of intestinal epithelial cells to promote bacterial attachment or entry. These data suggest that the NOD1 signaling pathway in intestinal epithelial cells provides an important sentinel function for detecting 'breaking and entering' by enteric pathogens.
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Affiliation(s)
- A Marijke Keestra
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Avenue, Davis CA 95616, USA
| | - Andreas J Bäumler
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Avenue, Davis CA 95616, USA.
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4
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Moreno L, Gatheral T. Therapeutic targeting of NOD1 receptors. Br J Pharmacol 2013; 170:475-85. [PMID: 23848281 PMCID: PMC3791987 DOI: 10.1111/bph.12300] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 06/30/2013] [Accepted: 07/04/2013] [Indexed: 12/11/2022] Open
Abstract
The nucleotide-binding oligomerization domain 1 (NOD1) protein is an intracellular receptor for breakdown products of peptidoglycan (PGN), an essential bacterial cell wall component. NOD1 responds to γ-D-glutamyl-meso-diaminopimelic acid, which is an epitope unique to PGN structures from all Gram-negative bacteria and certain Gram-positive bacteria. Upon ligand recognition, NOD1 undergoes conformational changes and self-oligomerization mediated by the nucleotide-binding NACHT domains, followed by the recruitment and activation of the serine threonine kinase receptor-interacting protein 2 leading to the activation of NF-κB and MAPK pathways and induction of inflammatory genes. Much of our knowledge is derived from seminal studies using mice deficient in NOD1 and confirming an essential role for NOD1 in the host immune response against gastrointestinal and respiratory pathogens. In addition, recent studies have revealed a role for intracellular NOD1 receptors in the regulation of vascular inflammation and metabolism. This review will discuss our current understanding of intracellular NOD1 receptors in host immunity and chronic inflammatory disorders with a focus on cardiovascular diseases. Although therapeutic advances may have to wait until the complex interplay with pathogens, danger signals, other pattern recognition receptors and overlapping metabolic pathways is further unravelled, the steadily growing body of knowledge suggest that NOD1 antagonism might represent attractive candidate to reduce excessive inflammation associated to intestinal, cardiovascular and metabolic diseases.
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Affiliation(s)
- L Moreno
- Ciber de Enfermedades Respiratorias (CIBERES), Bunyola, Spain; Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
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5
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Hung SC, Choi CH, Said-Sadier N, Johnson L, Atanasova KR, Sellami H, Yilmaz Ö, Ojcius DM. P2X4 assembles with P2X7 and pannexin-1 in gingival epithelial cells and modulates ATP-induced reactive oxygen species production and inflammasome activation. PLoS One 2013; 8:e70210. [PMID: 23936165 PMCID: PMC3723664 DOI: 10.1371/journal.pone.0070210] [Citation(s) in RCA: 132] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 06/17/2013] [Indexed: 01/17/2023] Open
Abstract
We have previously reported that Porphyromonas gingivalis infection of gingival epithelial cells (GEC) requires an exogenous danger signal such as ATP to activate an inflammasome and caspase-1, thereby inducing secretion of interleukin (IL)-1β. Stimulation with extracellular ATP also stimulates production of reactive oxygen species (ROS) in GEC. However, the mechanism by which ROS is generated in response to ATP, and the role that different purinergic receptors may play in inflammasome activation, is still unclear. In this study, we revealed that the purinergic receptor P2X4 is assembled with the receptor P2X7 and its associated pore, pannexin-1. ATP induces ROS production through a complex consisting of the P2X4, P2X7, and pannexin-1. P2X7−mediated ROS production can activate the NLRP3 inflammasome and caspase-1. Furthermore, separate depletion or inhibition of P2X4, P2X7, or pannexin-1 complex blocks IL-1β secretion in P. gingivalis-infected GEC following ATP treatment. However, activation via P2X4 alone induces ROS generation but not inflammasome activation. These results suggest that ROS is generated through stimulation of a P2X4/P2X7/pannexin-1 complex, and reveal an unexpected role for P2X4, which acts as a positive regulator of inflammasome activation during microbial infection.
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Affiliation(s)
- Shu-Chen Hung
- Department of Molecular Cell Biology, University of California Merced, Merced, California, United States of America
- Health Sciences Research Institute, University of California Merced, Merced, California, United States of America
| | - Chul Hee Choi
- Department of Periodontology, University of Florida, Gainesville, Florida, United States of America
| | - Najwane Said-Sadier
- Department of Molecular Cell Biology, University of California Merced, Merced, California, United States of America
- Health Sciences Research Institute, University of California Merced, Merced, California, United States of America
| | - Larry Johnson
- Department of Molecular Cell Biology, University of California Merced, Merced, California, United States of America
- Health Sciences Research Institute, University of California Merced, Merced, California, United States of America
| | | | - Hanen Sellami
- Department of Molecular Cell Biology, University of California Merced, Merced, California, United States of America
- Health Sciences Research Institute, University of California Merced, Merced, California, United States of America
- Department of Microbiology, Habib Bourguiba University Hospital, Medical School of Sfax, University of Sfax, Sfax, Tunisia
| | - Özlem Yilmaz
- Department of Periodontology, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - David M. Ojcius
- Department of Molecular Cell Biology, University of California Merced, Merced, California, United States of America
- Health Sciences Research Institute, University of California Merced, Merced, California, United States of America
- * E-mail:
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6
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Sha Z, Abernathy JW, Wang S, Li P, Kucuktas H, Liu H, Peatman E, Liu Z. NOD-like subfamily of the nucleotide-binding domain and leucine-rich repeat containing family receptors and their expression in channel catfish. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2009; 33:991-999. [PMID: 19414032 DOI: 10.1016/j.dci.2009.04.004] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Revised: 04/03/2009] [Accepted: 04/27/2009] [Indexed: 05/27/2023]
Abstract
The NLRs (nucleotide-binding domain and leucine-rich repeat containing family receptors) are a recently identified family of pattern recognition receptors in vertebrates. Several subfamilies of NLRs have been characterized in human, mouse, and zebrafish, but studies of NLRs in other species, especially teleost species, have been lacking. Here we report characterization of five NLRs from channel catfish: NOD1, NOD2, NLRC3, NLRC5, and NLRX1. Structural analysis indicated that the genes were organized in a similar fashion as in the mammals and in zebrafish. Phylogenetic analysis suggested that they were orthologous to the NOD-like subfamily of NLRs. All five NOD-like genes exist as a single copy gene in the catfish genome. Hybridization of gene-specific probes allowed mapping of three NLR genes to the catfish physical map, laying a foundation for genome characterization and for establishing orthologies with NLR genes from other species. These genes are widely expressed in various tissues and leukocyte cell lines. While the majority of the NLR genes appeared to be constitutively expressed, NOD1 was induced after infection with a bacterial pathogen, Edwardsiella ictaluri, the causative agent of enteric septicemia of catfish (ESC), suggesting its involvement in immunity against the intracellular pathogen.
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Affiliation(s)
- Zhenxia Sha
- The Fish Molecular Genetics and Biotechnology Laboratory, Department of Fisheries and Allied Aquacultures, Program of Cell and Molecular Biosciences, Aquatic Genomics Unit, Auburn University, 203 Swingle Hall, Auburn, AL 36849 USA
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7
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Becker CE, O'Neill LAJ. Inflammasomes in inflammatory disorders: the role of TLRs and their interactions with NLRs. Semin Immunopathol 2007; 29:239-48. [PMID: 17805544 DOI: 10.1007/s00281-007-0081-4] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2007] [Accepted: 07/05/2007] [Indexed: 01/01/2023]
Abstract
The innate immune system relies on a variety of pattern recognition receptors (PRRs) such as Toll-like receptors (TLRs) and NOD-like receptors (NLRs) to sense microbial structures that are present in pathogens. Various levels of crosstalk between the TLR and NLR pathways have been described, most notably the description of a molecular scaffold complex, termed the inflammasome, which requires input from both pathways and leads to the activation of the proinflammatory cytokines interleukin (IL)-1beta and IL-18. In certain cases, the inflammatory process becomes dysregulated and chronic inflammatory diseases may develop. Understanding the interactions of the TLR and NLR pathways will provide further clues to the pathogeneses of these diseases and to the development of efficient therapies to combat them.
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Affiliation(s)
- Christine E Becker
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland.
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8
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Wiedmaier N, Müller S, Köberle M, Manncke B, Krejci J, Autenrieth IB, Bohn E. Bacteria induce CTGF and CYR61 expression in epithelial cells in a lysophosphatidic acid receptor-dependent manner. Int J Med Microbiol 2007; 298:231-43. [PMID: 17765657 DOI: 10.1016/j.ijmm.2007.06.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2006] [Revised: 04/20/2007] [Accepted: 06/05/2007] [Indexed: 01/25/2023] Open
Abstract
Cysteine-rich protein 61 (Cyr61/CCN1) and connective tissue growth factor (CTGF/CCN2) are members of the CCN (CYR61, CTGF, nephroblastoma overexpressed gene) family and exert pleiotropic functions such as regulation of adhesion, migration, extracellular matrix deposition, or cell differentiation, and play an important role in wound healing. This study focused on the nature of the so far unknown CTGF and CYR61 mRNA expression of epithelial cells after infection with bacteria. We demonstrate that infection of epithelial cells with attenuated Yersinia enterocolitica lacking the virulence plasmid pYV leads to the expression of CYR61 and CTGF. Virulent Y. enterocolitica bearing the pYV virulence plasmid suppressed the mRNA expression of these genes. Yersinia-mediated inhibition of CTGF and CYR61 mRNA expression is partially mediated by the cysteine protease YopT. Further characterization of the Yersinia factors, which trigger CTGF and CYR61 mRNA expression, demonstrated that these factors were secreted and could be enriched in lipid extracts. Beside Yersinia, several other bacteria such as Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, or Staphylococcus aureus, as well as supernatants of these bacteria induced CTGF and CYR61 expression. Blocking experiments with the lysophosphatidic acid (LPA) receptor-specific inhibitor Ki16425 suggest a general involvement of LPA receptors in bacteria-triggered CTGF and CYR61 expression. These data suggest that LPA receptor-dependent expression of CTGF and CYR61 represents a common host response after interaction with bacteria.
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Affiliation(s)
- Nina Wiedmaier
- Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen, Elfriede-Aulhorn-Str. 6, D-72076 Tübingen, Germany
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9
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Park JH, Kim YG, Shaw M, Kanneganti TD, Fujimoto Y, Fukase K, Inohara N, Núñez G. Nod1/RICK and TLR signaling regulate chemokine and antimicrobial innate immune responses in mesothelial cells. THE JOURNAL OF IMMUNOLOGY 2007; 179:514-21. [PMID: 17579072 DOI: 10.4049/jimmunol.179.1.514] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Mesothelial cells that line the serous cavities and outer surface of internal organs are involved in inflammatory responses induced by microbial stimuli and bacterial infection. Upon exposure to bacterial products, mesothelial cells secrete chemokines, but the signaling pathways by which these cells recognize bacteria to mediate innate immune responses remain largely unknown. We report that stimulation of primary peritoneal mesothelial cells via nucleotide-binding oligomerization domain (Nod)1, a member of the intracytoplasmic Nod-like receptor family, induced potent secretion of the chemokines CXCL1 and CCL2 as well as expression of inducible NO synthase and such responses required the kinase RICK. Mesothelial cells also produced chemokines in response to TLR2, TLR3, TLR4, and TLR5 agonists, but unlike that induced by Nod1 stimulation, the TLR-mediated responses were independent of RICK. Yet, Nod1 stimulation of mesothelial cells via RICK enhanced chemokine secretion induced by LPS or IFN-gamma and cooperated with IFN-gamma in the production of NO. The i.p. administration of KF1B, a synthetic Nod1 agonist, elicited chemokine production in the serum and peritoneal fluid as well as the recruitment of neutrophils into the peritoneal cavity of wild-type mice, but not RICK-deficient mice. Finally, infection of mesothelial cells with Listeria monocytogenes induced production of CXCL1 and this response was significantly reduced in Nod1- or RICK-deficient cells. These results define mesothelial cells as microbial sensors through TLRs and Nod-like receptors and identify Nod1 and RICK as important mediators of chemokine and antimicrobial responses in mesothelial cells.
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Affiliation(s)
- Jong-Hwan Park
- Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, 1500 East Medical Center Drive, Ann Arbor, MI 48109, USA
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10
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Abstract
Approximately 500 mya two types of recombinatorial adaptive immune systems appeared in vertebrates. Jawed vertebrates generate a diverse repertoire of B and T cell antigen receptors through the rearrangement of immunoglobulin V, D, and J gene fragments, whereas jawless fish assemble their variable lymphocyte receptors through recombinatorial usage of leucine-rich repeat (LRR) modular units. Invariant germ line-encoded, LRR-containing proteins are pivotal mediators of microbial recognition throughout the plant and animal kingdoms. Whereas the genomes of plants and deuterostome and chordate invertebrates harbor large arsenals of recognition receptors primarily encoding LRR-containing proteins, relatively few innate pattern recognition receptors suffice for survival of pathogen-infected nematodes, insects, and vertebrates. The appearance of a lymphocyte-based recombinatorial system of anticipatory immunity in the vertebrates may have been driven by a need to facilitate developmental and morphological plasticity in addition to the advantage conferred by the ability to recognize a larger portion of the antigenic world.
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Affiliation(s)
- Zeev Pancer
- Center of Marine Biotechnology, University of Maryland Biotechnology Institute, Baltimore, Maryland 21202, USA.
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11
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Abstract
The human gastrointestinal (GI) tract is colonized by non-pathogenic commensal microflora and frequently exposed to many pathogenic organisms. For the maintenance of GI homeostasis, the host must discriminate between pathogenic and non-pathogenic organisms and initiate effective and appropriate immune and inflammatory responses. Mammalian toll-like receptors (TLRs) are members of the pattern-recognition receptor (PRR) family that plays a central role in the initiation of innate cellular immune responses and the subsequent adaptive immune responses to microbial pathogens. Recent studies have shown that gastrointestinal epithelial cells express almost all TLR subtypes characterized to date and that the expression and activation of TLRs in the GI tract are tightly and coordinately regulated. This review summarizes the current understanding of the crucial dual roles of TLRs in the development of host innate and adaptive immune responses to GI infections and the maintenance of the immune tolerance to commensal bacteria through down-regulation of surface expression of TLRs in intestinal epithelial cells.
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Magalhaes JG, Philpott DJ, Nahori MA, Jéhanno M, Fritz J, Bourhis LL, Viala J, Hugot JP, Giovannini M, Bertin J, Lepoivre M, Mengin-Lecreulx D, Sansonetti PJ, Girardin SE. Murine Nod1 but not its human orthologue mediates innate immune detection of tracheal cytotoxin. EMBO Rep 2006; 6:1201-7. [PMID: 16211083 PMCID: PMC1369207 DOI: 10.1038/sj.embor.7400552] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2005] [Revised: 08/18/2005] [Accepted: 09/09/2005] [Indexed: 01/01/2023] Open
Abstract
Tracheal cytotoxin (TCT) was originally described as the minimal effector that was able to reproduce the cytotoxic response of Bordetella pertussis on ciliated epithelial cells. This molecule triggers pleiotropic effects such as immune stimulation or slow-wave sleep modulation. Further characterization identified TCT as a specific diaminopimelic acid (DAP)-containing muropeptide, GlcNAc-(anhydro)MurNAc-L-Ala-D-Glu-mesoDAP-D-Ala. Here, we show that the biological activity of TCT depends on Nod1, an intracellular sensor of bacterial peptidoglycan. However, Nod1-dependent detection of TCT was found to be host specific, as human Nod1 (hNod1) poorly detected TCT, whereas mouse Nod1 (mNod1) did so efficiently. More generally, hNod1 required a tripeptide (L-Ala-D-Glu-mesoDAP) for efficient sensing of peptidoglycan, whereas mNod1 detected a tetrapeptide structure (L-Ala-D-Glu-mesoDAP-D-Ala). In murine macrophages, TCT stimulated cytokine secretion and NO production through Nod1. Finally, in vivo, injection of the tetrapeptide structure in mice triggered a transient yet strong release of cytokines into the bloodstream and the maturation of macrophages, in a Nod1-dependent manner. This study thereby identifies Nod1 as the long sought after sensor of TCT in mammals.
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Affiliation(s)
- Joao Gamelas Magalhaes
- Unité de Pathogénie Microbienne Moléculaire INSERM U389
- These authors contributed equally to this work
| | - Dana J Philpott
- Groupe Immunité Innée et Signalisation
- These authors contributed equally to this work
- Tel: +33 1 45 68 85 93; E-mail:
| | - Marie-Anne Nahori
- Unité des Interactions Bactéries-Cellules, Institut Pasteur, 28, Rue du Dr. Roux, 75724 Paris Cedex 15, France
| | | | | | | | | | - Jean-Pierre Hugot
- Groupe Inserm Avenir, Hôpital Robert Debré, 48, Bd Serurier, 75019 Paris, France
| | - Marco Giovannini
- Génomique fonctionnelle des tumeurs solides, Inserm U674, Paris, France
| | - John Bertin
- Synta Pharmaceuticals Corp., 45 Hartwell Ave, Lexington, Massachusetts 0242, USA
| | | | - Dominique Mengin-Lecreulx
- Enveloppes Bactériennes et Antibiotiques, IBBMC, UMR 8619 CNRS, Université Paris-Sud, Bât. 430, 91405 Orsay, France
| | | | - Stephen E Girardin
- Unité de Pathogénie Microbienne Moléculaire INSERM U389
- Groupe Inserm Avenir Peptidoglycan and Innate Immunity, Institut Pasteur, 28, Rue du Dr. Roux, 75724 Paris Cedex 15, France
- Tel: +33 1 40 61 37 71; E-mail:
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13
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Girardin SE, Jéhanno M, Mengin-Lecreulx D, Sansonetti PJ, Alzari PM, Philpott DJ. Identification of the critical residues involved in peptidoglycan detection by Nod1. J Biol Chem 2005; 280:38648-56. [PMID: 16172124 DOI: 10.1074/jbc.m509537200] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Nod1 is an intracellular pattern recognition molecule activated following bacterial infection, which senses a specific muropeptide (l-Ala-d-Glu-meso-DAP (diaminopimelic acid); "Tri(DAP)") from peptidoglycan. Here we investigated the molecular basis of Tri(DAP) sensing by human (h) Nod1. Our results identified the domain responsible for Tri(DAP) detection in the center of the concave surface of hNod1 leucine-rich repeat domain. Amino acid residues critical for sensing define a contiguous surface patch that is largely conserved in Nod1 proteins from different species. Accordingly, the distinct specificities of human versus murine Nod1 toward muropeptide detection were also found to lie in this central cleft. Several splicing variants of Nod1 lacking repeats 7-9 have been characterized recently, the relative balance of which is thought to correlate with the onset of asthma or inflammatory bowel disease. We demonstrated that these isoforms failed to transduce NF-kappaB activation upon muropeptide stimulation. This study provided insights into the molecular mechanisms responsible for the detection of bacterial peptidoglycan by Nod1 and suggested that defects in Nod1-dependent peptidoglycan sensing may contribute to elicit certain inflammatory disorders.
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Affiliation(s)
- Stephen E Girardin
- Unité de Pathogénie Microbienne Moléculaire, INSERM U389, Institut Pasteur, 28 Rue du Dr. Roux, 75724 Paris Cedex 15, France.
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MacDonald TT, Gordon JN. Bacterial regulation of intestinal immune responses. Gastroenterol Clin North Am 2005; 34:401-12, vii-viii. [PMID: 16084304 DOI: 10.1016/j.gtc.2005.05.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Thomas T MacDonald
- Division of Infection, Inflammation and Repair, University of Southampton School of Medicine, Southampton, Hampshire, United Kingdom.
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Vijay-Kumar M, Gentsch JR, Kaiser WJ, Borregaard N, Offermann MK, Neish AS, Gewirtz AT. Protein kinase R mediates intestinal epithelial gene remodeling in response to double-stranded RNA and live rotavirus. THE JOURNAL OF IMMUNOLOGY 2005; 174:6322-31. [PMID: 15879132 DOI: 10.4049/jimmunol.174.10.6322] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
As sentinels of host defense, intestinal epithelial cells respond to the viral pathogen rotavirus by activating a gene expression that promotes immune cell recruitment and activation. We hypothesized that epithelial sensing of rotavirus might target dsRNA, which can be detected by TLR3 or protein kinase R (PKR). Accordingly, we observed that synthetic dsRNA, polyinosinic acid:cytidylic acid (poly(I:C)), potently induced gene remodeling in model intestinal epithelia with the specific pattern of expressed genes, including both classic proinflammatory genes (e.g., IL-8), as well as genes that are classically activated in virus-infected cells (e.g., IFN-responsive genes). Poly(I:C)-induced IL-8 was concentration dependent (2-100 mug/ml) and displayed slower kinetics compared with IL-8 induced by bacterial flagellin (ET(50) approximately 24 vs 8 h poly(I:C) vs flagellin, respectively). Although model epithelia expressed detectable TLR3 mRNA, neither TLR3-neutralizing Abs nor chloroquine, which blocks activation of intracellular TLR3, attenuated epithelial responses to poly(I:C). Conversely, poly(I:C)-induced phosphorylation of PKR and inhibitors of PKR, 2-aminopurine and adenine, ablated poly(I:C)-induced gene expression but had no effect on gene expression induced by flagellin, thus suggesting that intestinal epithelial cell detection of dsRNA relies on PKR. Consistent with poly(I:C) detection by an intracellular molecule such as PKR, we observed that both uptake of and responses to poly(I:C) were polarized to the basolateral side. Lastly, we observed that the pattern of pharmacologic inhibition of responses to poly(I:C) was identical to that seen in response to infection by live rotavirus, indicating a potentially important role for PKR in activating intestinal epithelial gene expression in rotavirus infection.
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Affiliation(s)
- Matam Vijay-Kumar
- Department of Pathology and Laboratory Medicine, Epithelial Pathobiology Unit, Emory University School of Medicine, Atlanta, GA 30322, USA
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Komatsuzawa H, Ouhara K, Yamada S, Fujiwara T, Sayama K, Hashimoto K, Sugai M. Innate defences against methicillin-resistantStaphylococcus aureus (MRSA) infection. J Pathol 2005; 208:249-60. [PMID: 16362993 DOI: 10.1002/path.1898] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The innate immune system is the primary defence against bacterial infection. Among the factors involved in innate defence, anti-microbial peptides produced by humans have recently attracted attention due to their relevance to some diseases and also to the development of new chemotherapeutic agents. Staphylococcus aureus is one of the major human pathogens, causing a variety of infections from suppurative disease to food poisoning. Methicillin-resistant S. aureus (MRSA) is a clinical problem and with the recent emergence of a vancomycin-resistant strain, this will pose serious problems in the near future. In investigating the molecular biology of S. aureus infections to develop new chemotherapeutic agents against MRSA infections, knowledge of the interaction of innate anti-microbial peptides with S. aureus is important. In vitro and in vivo experiments demonstrate that exposure of S. aureus to host cells can induce the anti-microbial peptides beta-defensin-2 (hBD2), hBD3, and LL37/CAP18. The induction level of these peptides differs among strains, as does the susceptibility of the strains, with MRSA strains exhibiting lower susceptibility. In summary, the susceptibility of S. aureus strains, including MRSA strains, to components of the innate immune system varies, with the MRSA strains showing more resistance to both innate immune factors and chemotherapeutic agents.
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Affiliation(s)
- Hitoshi Komatsuzawa
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical Sciences, Japan. hkomatsu@hiroshi,a-u.ac.jp
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