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Fritz JH, Girardin SE. How Toll-like receptors and Nod-like receptors contribute to innate immunity in mammals. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/09680519050110060301] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Innate immune detection of pathogens relies on specific classes of microbial sensors called pattern-recognition molecules (PRM). In mammals, such PRM include Toll-like receptors (TLRs) and the intracellular proteins NOD1 and NOD2, which belong to the family of Nod-like receptors (NLRs). Over the last decade as these molecules were discovered, a function in innate immunity has been assigned for the majority of them and, for most, the microbial motifs that these molecules detect were identified. One of the next challenges in innate immunity is to establish a better understanding of the complex interplay between signaling pathways induced simultaneously by distinct PRMs and how this affects tailoring first-line responses and the induction of adaptive immunity to a given pathogen.
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Affiliation(s)
- Jörg H. Fritz
- Immunité Innée et Signalisation Laboratoire, Institut Pasteur, Paris, France
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Wiest R, Lawson M, Geuking M. Pathological bacterial translocation in liver cirrhosis. J Hepatol 2014; 60:197-209. [PMID: 23993913 DOI: 10.1016/j.jhep.2013.07.044] [Citation(s) in RCA: 524] [Impact Index Per Article: 52.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 06/20/2013] [Accepted: 07/19/2013] [Indexed: 12/11/2022]
Affiliation(s)
- Reiner Wiest
- Department Gastroenterology, Inselspital, University Hospital, Bern 3010, Switzerland.
| | - Melissa Lawson
- Maurice Müller Laboratories, Universitätsklinik für Viszerale Chirurgie und Medizin (UVCM), University of Bern, Bern 3010, Switzerland
| | - Markus Geuking
- Maurice Müller Laboratories, Universitätsklinik für Viszerale Chirurgie und Medizin (UVCM), University of Bern, Bern 3010, Switzerland
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Dodds PN, Rathjen JP. Plant immunity: towards an integrated view of plant-pathogen interactions. Nat Rev Genet 2010. [PMID: 20585331 DOI: 10.1038/nrg2812x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Plants are engaged in a continuous co-evolutionary struggle for dominance with their pathogens. The outcomes of these interactions are of particular importance to human activities, as they can have dramatic effects on agricultural systems. The recent convergence of molecular studies of plant immunity and pathogen infection strategies is revealing an integrated picture of the plant-pathogen interaction from the perspective of both organisms. Plants have an amazing capacity to recognize pathogens through strategies involving both conserved and variable pathogen elicitors, and pathogens manipulate the defence response through secretion of virulence effector molecules. These insights suggest novel biotechnological approaches to crop protection.
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Affiliation(s)
- Peter N Dodds
- Commonwealth Scientific and Industrial Research Organisation, Division of Plant Industry, GPO BOX 1600, Canberra, Australian Capital Territory 2601, Australia.
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Dodds PN, Rathjen JP. Plant immunity: towards an integrated view of plant-pathogen interactions. Nat Rev Genet 2010. [PMID: 20585331 DOI: 10.1038/nrg2812>] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Plants are engaged in a continuous co-evolutionary struggle for dominance with their pathogens. The outcomes of these interactions are of particular importance to human activities, as they can have dramatic effects on agricultural systems. The recent convergence of molecular studies of plant immunity and pathogen infection strategies is revealing an integrated picture of the plant-pathogen interaction from the perspective of both organisms. Plants have an amazing capacity to recognize pathogens through strategies involving both conserved and variable pathogen elicitors, and pathogens manipulate the defence response through secretion of virulence effector molecules. These insights suggest novel biotechnological approaches to crop protection.
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Affiliation(s)
- Peter N Dodds
- Commonwealth Scientific and Industrial Research Organisation, Division of Plant Industry, GPO BOX 1600, Canberra, Australian Capital Territory 2601, Australia.
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Rafiqi M, Bernoux M, Ellis JG, Dodds PN. In the trenches of plant pathogen recognition: Role of NB-LRR proteins. Semin Cell Dev Biol 2009; 20:1017-24. [PMID: 19398031 DOI: 10.1016/j.semcdb.2009.04.010] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2009] [Revised: 04/17/2009] [Accepted: 04/17/2009] [Indexed: 01/05/2023]
Abstract
As in nearly every discipline of plant biology, new insights are constantly changing our understanding of plant immunity. It is now clear that plant immunity is controlled by two layers of inducible responses: basal responses triggered by conserved microbial features and specific responses triggered by gene-for-gene recognition of pathogen effector proteins by host resistance (R) proteins. The nucleotide-binding domain leucine-rich repeat (NB-LRR) class of R proteins plays a major role in the combat against a wide range of plant pathogens. The variation that has been generated and is maintained within these conserved proteins has diversified their specificity, subcellular localisations, activation and recognition mechanisms, allowing them to specifically adapt to different plant-pathogen interaction systems. This review addresses recent advances in the molecular role of NB-LRR proteins in pathogen recognition and activation of plant defence responses.
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Affiliation(s)
- Maryam Rafiqi
- Plant Cell Biology Group, Research School of Biological Sciences, Australian National University, Canberra, ACT 2601, Australia.
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Abstract
Bacterial peptidoglycan amidases are a large and diverse group of enzymes. During the last few years, genomic sequence information has accumulated to an extent such that lists of proven or predicted peptidoglycan amidases can now be expected to be fairly complete. Moreover, representative crystal structures for most groups of phylogenetically related peptidoglycan amidases have been solved. Here, sequence and structural information is combined with published biochemical findings to demonstrate that (a) peptidoglycan amidases have evolved for almost every bond that occurs in peptidoglycan, (b) there are enzymes that share the fold, yet cleave different bonds and (c) there are enzymes that have entirely different folds and must have evolved independently, and yet cleave the same peptide bond. It is shown that despite these complications, some rules can be deduced from the available biochemical and structural information that can be useful to predict the specificity of hypothetical peptidoglycan hydrolases, for which only sequence information is available.
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Affiliation(s)
- Małgorzata Firczuk
- International Institute of Molecular and Cell Biology, Warsaw, Poland; and Max-Planck-Institute of Molecular Cell Biology and Genetics, Dresden, Germany
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Wang X, Rocheleau TA, Fuchs JF, Christensen BM. Beta 1, 3-glucan recognition protein from the mosquito, Armigeres subalbatus, is involved in the recognition of distinct types of bacteria in innate immune responses. Cell Microbiol 2006; 8:1581-90. [PMID: 16984413 DOI: 10.1111/j.1462-5822.2006.00732.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The activation of an immune response to invading microorganisms generally requires recognition by pattern recognition receptors. Beta 1, 3-glucan recognition proteins (GRPs) have specific affinity for beta 1, 3-glucan, a component on the surface of fungi and bacteria. In this study, we show that GRP from Armigeres subalbatus mosquitoes (AsGRP) is able to bind different bacterial species, and that this binding varies from species to species and is independent of Gram type. AsGRP knockdown with double-stranded RNA increases the mortality of mosquitoes to those bacteria that strongly bind AsGRP, but not to bacteria that do not detectably bind AsGRP. This increase in susceptibility is partially evidenced by decreased melanization in Salmonella typhimurium. Furthermore, AsGRP expression is differentially affected by the presence of different species of bacteria. These results demonstrate that AsGRP is selective in its affinity to different bacteria and; therefore, plays a role in the antibacterial immune response of mosquitoes.
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Affiliation(s)
- Xinguo Wang
- Department of Animal Health and Biomedical Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA
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Chinchilla D, Bauer Z, Regenass M, Boller T, Felix G. The Arabidopsis receptor kinase FLS2 binds flg22 and determines the specificity of flagellin perception. THE PLANT CELL 2006; 18:465-76. [PMID: 16377758 PMCID: PMC1356552 DOI: 10.1105/tpc.105.036574] [Citation(s) in RCA: 550] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Flagellin, the main building block of the bacterial flagellum, acts as a pathogen-associated molecular pattern triggering the innate immune response in animals and plants. In Arabidopsis thaliana, the Leu-rich repeat transmembrane receptor kinase FLAGELLIN SENSITIVE2 (FLS2) is essential for flagellin perception. Here, we demonstrate the specific interaction of the elicitor-active epitope flg22 with the FLS2 protein by chemical cross-linking and immunoprecipitation. The functionality of this receptor was further tested by heterologous expression of the Arabidopsis FLS2 gene in tomato (Lycopersicon esculentum) cells. The perception of flg22 in tomato differs characteristically from that in Arabidopsis. Expression of Arabidopsis FLS2 conferred an additional flg22-perception system on the cells of tomato, which showed all of the properties characteristic of the perception of this elicitor in Arabidopsis. In summary, these results show that FLS2 constitutes the pattern-recognition receptor that determines the specificity of flagellin perception.
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Affiliation(s)
- Delphine Chinchilla
- Zürich-Basel Plant Science Center, Botanisches Institut der Universität Basel, CH-4056 Basel, Switzerland
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Travassos LH, Carneiro LAM, Girardin SE, Boneca IG, Lemos R, Bozza MT, Domingues RCP, Coyle AJ, Bertin J, Philpott DJ, Plotkowski MC. Nod1 participates in the innate immune response to Pseudomonas aeruginosa. J Biol Chem 2005; 280:36714-8. [PMID: 16150702 DOI: 10.1074/jbc.m501649200] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The mammalian innate immune system recognizes pathogen-associated molecular patterns through pathogen recognition receptors. Nod1 has been described recently as a cytosolic receptor that detects specifically diaminopimelate-containing muropeptides from Gram-negative bacteria peptidoglycan. In the present study we investigated the potential role of Nod1 in the innate immune response against the opportunistic pathogen Pseudomonas aeruginosa. We demonstrate that Nod1 detects the P. aeruginosa peptidoglycan leading to NF-kappaB activation and that this activity is diminished in epithelial cells expressing a dominant-negative Nod1 construct or in mouse embryonic fibroblasts from Nod1 knock-out mice infected with P. aeruginosa. Finally, we demonstrate that the cytokine secretion kinetics and bacterial killing are altered in Nod1-deficient cells infected with P. aeruginosa in the early stages of infection.
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Affiliation(s)
- Leonardo H Travassos
- Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ Cep. 21.941 590, Brazil.
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Singer M, Sansonetti PJ. IL-8 is a key chemokine regulating neutrophil recruitment in a new mouse model of Shigella-induced colitis. THE JOURNAL OF IMMUNOLOGY 2004; 173:4197-206. [PMID: 15356171 DOI: 10.4049/jimmunol.173.6.4197] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The lack of a mouse model of acute rectocolitis mimicking human bacillary dysentery in the presence of invasive Shigella is a major handicap to study the pathogenesis of the disease and to develop a Shigella vaccine. The inability of the mouse intestinal mucosa to elicit an inflammatory infiltrate composed primarily of polymorphonuclear leukocytes (PMN) may be due to a defect in epithelial invasion, in the sensing of invading bacteria, or in the effector mechanisms that recruit the PMN infiltrate. We demonstrate that the BALB/cJ mouse colonic epithelium not only can be invaded by Shigella, but also elicits an inflammatory infiltrate that, however, lacks PMN. This observation points to a major defect of mice in effector mechanisms, particularly the lack of expression of the CXC chemokine, IL-8. Indeed, this work demonstrates that the delivery of recombinant human IL-8, together with Shigella infection of the colonic epithelial surface, causes an acute colitis characterized by a strong PMN infiltrate that, by all criteria, including transcription profiles of key mediators of the innate/inflammatory response and histopathological lesions, mimics bacillary dysentery. This is a major step forward in the development of a murine model of bacillary dysentery.
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Affiliation(s)
- Monique Singer
- Unité de Pathogénie Microbienne Moléculaire, Institut National de la Santé et de la Recherche Médicale U389, Institut Pasteur, Paris, France
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Pili-Floury S, Leulier F, Takahashi K, Saigo K, Samain E, Ueda R, Lemaitre B. In Vivo RNA Interference Analysis Reveals an Unexpected Role for GNBP1 in the Defense against Gram-positive Bacterial Infection in Drosophila Adults. J Biol Chem 2004; 279:12848-53. [PMID: 14722090 DOI: 10.1074/jbc.m313324200] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The Drosophila immune system discriminates between different classes of infectious microbes and responds with pathogen-specific defense reactions via the selective activation of the Toll and the immune deficiency (Imd) signaling pathways. The Toll pathway mediates most defenses against Gram-positive bacteria and fungi, whereas the Imd pathway is required to resist Gram-negative bacterial infection. Microbial recognition is achieved through peptidoglycan recognition proteins (PGRPs); Gram-positive bacteria activate the Toll pathway through a circulating PGRP (PGRP-SA), and Gram-negative bacteria activate the Imd pathway via PGRP-LC, a putative transmembrane receptor, and PGRP-LE. Gram-negative binding proteins (GNBPs) were originally identified in Bombyx mori for their capacity to bind various microbial compounds. Three GNBPs and two related proteins are encoded in the Drosophila genome, but their function is not known. Using inducible expression of GNBP1 double-stranded RNA, we now demonstrate that GNBP1 is required for Toll activation in response to Gram-positive bacterial infection; GNBP1 double-stranded RNA expression renders flies susceptible to Gram-positive bacterial infection and reduces the induction of the antifungal peptide encoding gene Drosomycin after infection by Gram-positive bacteria but not after fungal infection. This phenotype induced by GNBP1 inactivation is identical to a loss-of-function mutation in PGRP-SA, and our genetic studies suggest that GNBP1 acts upstream of the Toll ligand Spätzle. Altogether, our results demonstrate that the detection of Gram-positive bacteria in Drosophila requires two putative pattern recognition receptors, PGRP-SA and GNBP1.
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