351
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A leucine-rich repeat assembly approach for homology modeling of the human TLR5-10 and mouse TLR11-13 ectodomains. J Mol Model 2010; 17:27-36. [PMID: 20352268 DOI: 10.1007/s00894-010-0697-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2009] [Accepted: 02/24/2010] [Indexed: 01/07/2023]
Abstract
So far, 13 groups of mammalian Toll-like receptors (TLRs) have been identified. Most TLRs have been shown to recognize pathogen-associated molecular patterns from a wide range of invading agents and initiate both innate and adaptive immune responses. The TLR ectodomains are composed of varying numbers and types of leucine-rich repeats (LRRs). As the crystal structures are currently missing for most TLR ligand-binding ectodomains, homology modeling enables first predictions of their three-dimensional structures on the basis of the determined crystal structures of TLR ectodomains. However, the quality of the predicted models that are generated from full-length templates can be limited due to low sequence identity between the target and templates. To obtain better templates for modeling, we have developed an LRR template assembly approach. Individual LRR templates that are locally optimal for the target sequence are assembled into multiple templates. This method was validated through the comparison of a predicted model with the crystal structure of mouse TLR3. With this method, we also constructed ectodomain models of human TLR5, TLR6, TLR7, TLR8, TLR9, and TLR10 and mouse TLR11, TLR12, and TLR13 that can be used as first passes for a computational simulation of ligand docking or to design mutation experiments. This template assembly approach can be extended to other repetitive proteins.
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352
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Zhang Q, Zmasek CM, Godzik A. Domain architecture evolution of pattern-recognition receptors. Immunogenetics 2010; 62:263-72. [PMID: 20195594 PMCID: PMC2858798 DOI: 10.1007/s00251-010-0428-1] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Accepted: 02/03/2010] [Indexed: 12/11/2022]
Abstract
In animals, the innate immune system is the first line of defense against invading microorganisms, and the pattern-recognition receptors (PRRs) are the key components of this system, detecting microbial invasion and initiating innate immune defenses. Two families of PRRs, the intracellular NOD-like receptors (NLRs) and the transmembrane Toll-like receptors (TLRs), are of particular interest because of their roles in a number of diseases. Understanding the evolutionary history of these families and their pattern of evolutionary changes may lead to new insights into the functioning of this critical system. We found that the evolution of both NLR and TLR families included massive species-specific expansions and domain shuffling in various lineages, which resulted in the same domain architectures evolving independently within different lineages in a process that fits the definition of parallel evolution. This observation illustrates both the dynamics of the innate immune system and the effects of "combinatorially constrained" evolution, where existence of the limited numbers of functionally relevant domains constrains the choices of domain architectures for new members in the family, resulting in the emergence of independently evolved proteins with identical domain architectures, often mistaken for orthologs.
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Affiliation(s)
- Qing Zhang
- Burnham Institute for Medical Research, 10901 North Torrey Pines Road, La Jolla, CA 92037 USA
| | - Christian M. Zmasek
- Burnham Institute for Medical Research, 10901 North Torrey Pines Road, La Jolla, CA 92037 USA
| | - Adam Godzik
- Burnham Institute for Medical Research, 10901 North Torrey Pines Road, La Jolla, CA 92037 USA
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093 USA
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353
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Zimmerman LM, Vogel LA, Bowden RM. Understanding the vertebrate immune system: insights from the reptilian perspective. J Exp Biol 2010; 213:661-71. [DOI: 10.1242/jeb.038315] [Citation(s) in RCA: 285] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Summary
Reptiles are ectothermic amniotes, providing the key link between ectothermic anamniotic fishes and amphibians, and endothermic amniotic birds and mammals. A greater understanding of reptilian immunity will provide important insights into the evolutionary history of vertebrate immunity as well as the growing field of eco-immunology. Like mammals, reptile immunity is complex and involves innate, cell-mediated and humoral compartments but, overall, there is considerably less known about immune function in reptiles. We review the current literature on each branch of the reptilian immune system, placing this information in context to other vertebrates. Further, we identify key areas that are prime for research as well as areas that are lagging because of lack of reagents in non-model systems.
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Affiliation(s)
- L. M. Zimmerman
- School of Biological Sciences, Illinois State University, Normal, IL 61790-4120, USA
| | - L. A. Vogel
- School of Biological Sciences, Illinois State University, Normal, IL 61790-4120, USA
| | - R. M. Bowden
- School of Biological Sciences, Illinois State University, Normal, IL 61790-4120, USA
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354
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Pauly JL, Smith LA, Rickert MH, Hutson A, Paszkiewicz GM. Review: Is lung inflammation associated with microbes and microbial toxins in cigarette tobacco smoke? Immunol Res 2010; 46:127-36. [PMID: 19763893 DOI: 10.1007/s12026-009-8117-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Chronic inflammation that has been observed for malignant and non-neoplastic lung diseases of smokers has been attributed to the numerous and diverse particulate ('tar')-phase and gas-phase chemicals in mainstream smoke, most of which arise from the burning of tobacco. The primary cell-mediator of lung inflammation is the macrophage. Most probably, inflammation is promoted also from some of the more than 50 other cell types of the lung. Cured tobacco in diverse types of cigarettes is known to harbor a plethora of bacteria (Gram-positive and Gram-negative), fungi (mold, yeast), spores, and is rich in endotoxin (lipopolysaccharide). Reviewed herein are recent observations of the authors' team and other investigators that support the hypothesis that lung inflammation of long-term smokers may be attributed in part to tobacco-associated bacterial and fungal components that have been identified in tobacco and tobacco smoke.
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Affiliation(s)
- John L Pauly
- Department of Immunology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA.
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355
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Gerardo NM, Altincicek B, Anselme C, Atamian H, Barribeau SM, de Vos M, Duncan EJ, Evans JD, Gabaldón T, Ghanim M, Heddi A, Kaloshian I, Latorre A, Moya A, Nakabachi A, Parker BJ, Pérez-Brocal V, Pignatelli M, Rahbé Y, Ramsey JS, Spragg CJ, Tamames J, Tamarit D, Tamborindeguy C, Vincent-Monegat C, Vilcinskas A. Immunity and other defenses in pea aphids, Acyrthosiphon pisum. Genome Biol 2010; 11:R21. [PMID: 20178569 PMCID: PMC2872881 DOI: 10.1186/gb-2010-11-2-r21] [Citation(s) in RCA: 304] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2009] [Revised: 10/07/2009] [Accepted: 02/23/2010] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Recent genomic analyses of arthropod defense mechanisms suggest conservation of key elements underlying responses to pathogens, parasites and stresses. At the center of pathogen-induced immune responses are signaling pathways triggered by the recognition of fungal, bacterial and viral signatures. These pathways result in the production of response molecules, such as antimicrobial peptides and lysozymes, which degrade or destroy invaders. Using the recently sequenced genome of the pea aphid (Acyrthosiphon pisum), we conducted the first extensive annotation of the immune and stress gene repertoire of a hemipterous insect, which is phylogenetically distantly related to previously characterized insects models. RESULTS Strikingly, pea aphids appear to be missing genes present in insect genomes characterized to date and thought critical for recognition, signaling and killing of microbes. In line with results of gene annotation, experimental analyses designed to characterize immune response through the isolation of RNA transcripts and proteins from immune-challenged pea aphids uncovered few immune-related products. Gene expression studies, however, indicated some expression of immune and stress-related genes. CONCLUSIONS The absence of genes suspected to be essential for the insect immune response suggests that the traditional view of insect immunity may not be as broadly applicable as once thought. The limitations of the aphid immune system may be representative of a broad range of insects, or may be aphid specific. We suggest that several aspects of the aphid life style, such as their association with microbial symbionts, could facilitate survival without strong immune protection.
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Affiliation(s)
- Nicole M Gerardo
- Department of Biology, Emory University, O Wayne Rollins Research Center, 1510 E. Clifton Road NE, Atlanta, GA, 30322, USA
| | - Boran Altincicek
- Interdisciplinary Research Center, Institute of Phytopathology and Applied Zoology, Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany
| | - Caroline Anselme
- Université de Lyon, INRA, INSA-Lyon, IFR41 BioEnvironnement et Santé, UMR203 BF2I, Biologie Fonctionnelle Insectes et Interactions, Bat. Louis-Pasteur 20 ave Albert-Einstein, F-69621 Villeurbanne, France
- UMR Interactions Biotiques et Santé Végétale, INRA 1301-CNRS 6243-Université de Nice-Sophia Antipolis, 400 routes des Chappe, F-06903 Sophia-Antipolis cedex, France
| | - Hagop Atamian
- Department of Nematology, Graduate Program in Genetics, Genomics and Bioinformatics, University of California, 900 University Ave, Riverside, CA 92521, USA
| | - Seth M Barribeau
- Department of Biology, Emory University, O Wayne Rollins Research Center, 1510 E. Clifton Road NE, Atlanta, GA, 30322, USA
| | - Martin de Vos
- Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA
| | - Elizabeth J Duncan
- Genetics Otago and The Laboratory for Evolution and Development, Department of Biochemistry, University of Otago, Box 56, Dunedin 9054, New Zealand
| | - Jay D Evans
- USDA-ARS Bee Research Lab, BARC-East Bldg 476, Beltsville, MD 20705, USA
| | - Toni Gabaldón
- Bioinformatics and Genomics Programme, Centre for Genomic Regulation (CRG), Doctor Aiguader 88, 08003 Barcelona, Spain
| | - Murad Ghanim
- Department of Entomology, The Volcani Center, Bet Dagan 50250, Israel
| | - Adelaziz Heddi
- Université de Lyon, INRA, INSA-Lyon, IFR41 BioEnvironnement et Santé, UMR203 BF2I, Biologie Fonctionnelle Insectes et Interactions, Bat. Louis-Pasteur 20 ave Albert-Einstein, F-69621 Villeurbanne, France
| | - Isgouhi Kaloshian
- Department of Nematology, Graduate Program in Genetics, Genomics and Bioinformatics, University of California, 900 University Ave, Riverside, CA 92521, USA
| | - Amparo Latorre
- Instituto Cavanilles de Biodiversidad y Biología Evolutiva, Universitat de València, Avenida Blasco Ibañez 13, 46071 València, Spain
- CIBER en Epidemiología y Salud Pública (CIBEResp) and Centro Superior de Investigación en Salud Pública (CSISP), Conselleria de Sanidad (Generalitat Valenciana), Avenida de Cataluña 21, 46020 València, Spain
| | - Andres Moya
- Instituto Cavanilles de Biodiversidad y Biología Evolutiva, Universitat de València, Avenida Blasco Ibañez 13, 46071 València, Spain
- CIBER en Epidemiología y Salud Pública (CIBEResp) and Centro Superior de Investigación en Salud Pública (CSISP), Conselleria de Sanidad (Generalitat Valenciana), Avenida de Cataluña 21, 46020 València, Spain
| | - Atsushi Nakabachi
- Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Benjamin J Parker
- Department of Biology, Emory University, O Wayne Rollins Research Center, 1510 E. Clifton Road NE, Atlanta, GA, 30322, USA
| | - Vincente Pérez-Brocal
- Université de Lyon, INRA, INSA-Lyon, IFR41 BioEnvironnement et Santé, UMR203 BF2I, Biologie Fonctionnelle Insectes et Interactions, Bat. Louis-Pasteur 20 ave Albert-Einstein, F-69621 Villeurbanne, France
- Instituto Cavanilles de Biodiversidad y Biología Evolutiva, Universitat de València, Avenida Blasco Ibañez 13, 46071 València, Spain
- CIBER en Epidemiología y Salud Pública (CIBEResp) and Centro Superior de Investigación en Salud Pública (CSISP), Conselleria de Sanidad (Generalitat Valenciana), Avenida de Cataluña 21, 46020 València, Spain
| | - Miguel Pignatelli
- Instituto Cavanilles de Biodiversidad y Biología Evolutiva, Universitat de València, Avenida Blasco Ibañez 13, 46071 València, Spain
- CIBER en Epidemiología y Salud Pública (CIBEResp) and Centro Superior de Investigación en Salud Pública (CSISP), Conselleria de Sanidad (Generalitat Valenciana), Avenida de Cataluña 21, 46020 València, Spain
| | - Yvan Rahbé
- Université de Lyon, INRA, INSA-Lyon, IFR41 BioEnvironnement et Santé, UMR203 BF2I, Biologie Fonctionnelle Insectes et Interactions, Bat. Louis-Pasteur 20 ave Albert-Einstein, F-69621 Villeurbanne, France
| | - John S Ramsey
- Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA
| | - Chelsea J Spragg
- Department of Biology, Emory University, O Wayne Rollins Research Center, 1510 E. Clifton Road NE, Atlanta, GA, 30322, USA
| | - Javier Tamames
- Instituto Cavanilles de Biodiversidad y Biología Evolutiva, Universitat de València, Avenida Blasco Ibañez 13, 46071 València, Spain
- CIBER en Epidemiología y Salud Pública (CIBEResp) and Centro Superior de Investigación en Salud Pública (CSISP), Conselleria de Sanidad (Generalitat Valenciana), Avenida de Cataluña 21, 46020 València, Spain
| | - Daniel Tamarit
- Instituto Cavanilles de Biodiversidad y Biología Evolutiva, Universitat de València, Avenida Blasco Ibañez 13, 46071 València, Spain
- CIBER en Epidemiología y Salud Pública (CIBEResp) and Centro Superior de Investigación en Salud Pública (CSISP), Conselleria de Sanidad (Generalitat Valenciana), Avenida de Cataluña 21, 46020 València, Spain
| | - Cecilia Tamborindeguy
- Plant Pathology and Plant-Microbe Biology Department, Cornell University, Tower Road, Ithaca, NY 14853, USA
- Department of Entomology, Texas A&M, College Station, TX 77843-2475, USA
| | - Caroline Vincent-Monegat
- Université de Lyon, INRA, INSA-Lyon, IFR41 BioEnvironnement et Santé, UMR203 BF2I, Biologie Fonctionnelle Insectes et Interactions, Bat. Louis-Pasteur 20 ave Albert-Einstein, F-69621 Villeurbanne, France
| | - Andreas Vilcinskas
- Interdisciplinary Research Center, Institute of Phytopathology and Applied Zoology, Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany
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356
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Bilbo SD, Tsang V. Enduring consequences of maternal obesity for brain inflammation and behavior of offspring. FASEB J 2010; 24:2104-15. [PMID: 20124437 DOI: 10.1096/fj.09-144014] [Citation(s) in RCA: 368] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Obesity is well characterized as a systemic inflammatory condition, and is also associated with cognitive disruption, suggesting a link between the two. We assessed whether peripheral inflammation in maternal obesity may be transferred to the offspring brain, in particular, the hippocampus, and thereby result in cognitive dysfunction. Rat dams were fed a high-saturated-fat diet (SFD), a high-trans-fat diet (TFD), or a low-fat diet (LFD) for 4 wk prior to mating, and remained on the diet throughout pregnancy and lactation. SFD/TFD exposure significantly increased body weight in both dams and pups compared to controls. Microglial activation markers were increased in the hippocampus of SFD/TFD pups at birth. At weaning and in adulthood, proinflammatory cytokine expression was strikingly increased in the periphery and hippocampus following a bacterial challenge [lipopolysaccharide (LPS)] in the SFD/TFD groups compared to controls. Microglial activation within the hippocampus was also increased basally in SFD rats, suggesting a chronic priming of the cells. Finally, there were marked changes in anxiety and spatial learning in SFD/TFD groups. These effects were all observed in adulthood, even after the pups were placed on standard chow at weaning, suggesting these outcomes were programmed early in life.
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Affiliation(s)
- Staci D Bilbo
- Duke University, Department of Psychology and Neuroscience, Durham, NC 27708, USA.
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357
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Arsenault RJ, Jalal S, Babiuk LA, Potter A, Griebel PJ, Napper S. Kinome analysis of Toll-like receptor signaling in bovine monocytes. J Recept Signal Transduct Res 2010; 29:299-311. [PMID: 19899953 DOI: 10.3109/10799890903295127] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The Toll-like receptors (TLRs) are a family of pathogen recognition receptors that alert the host to the presence of microbial challenge. Each TLR responds to a specific microbial associated ligand. For example, TLR4 is activated by lipopolysaccharide (LPS), whereas TLR9 responds to microbial DNA (CpGs). In this report signal transduction responses of bovine monocytes to stimulation with LPS and CpG are described through a bovine-specific peptide array. In addition to confirming activation of the defined TLR pathway in bovine cells, unique phosphorylation events not previously attributed to TLR signaling are described and validated. For example, array data predicts phosphorylation of Tyr40 of Etk in response to LPS, but not CpG, stimulation as well as the activation of oxidative burst in CpG, but not LPS. This investigation confirms interspecies conservation of the TLR pathway in bovine as well as providing insight into the complexity and mechanisms of TLR signaling.
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Affiliation(s)
- Ryan J Arsenault
- Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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358
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Juarez E, Nuñez C, Sada E, Ellner JJ, Schwander SK, Torres M. Differential expression of Toll-like receptors on human alveolar macrophages and autologous peripheral monocytes. Respir Res 2010; 11:2. [PMID: 20051129 PMCID: PMC2817655 DOI: 10.1186/1465-9921-11-2] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2009] [Accepted: 01/05/2010] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Toll-like receptors (TLRs) are critical components in the regulation of pulmonary immune responses and the recognition of respiratory pathogens such as Mycobacterium Tuberculosis (M.tb). Through examination of human alveolar macrophages this study attempts to better define the expression profiles of TLR2, TLR4 and TLR9 in the human lung compartment which are as yet still poorly defined. METHODS Sixteen healthy subjects underwent venipuncture, and eleven subjects underwent additional bronchoalveolar lavage to obtain peripheral blood mononuclear and bronchoalveolar cells, respectively. Surface and intracellular expression of TLRs was assessed by fluorescence-activated cell sorting and qRT-PCR. Cells were stimulated with TLR-specific ligands and cytokine production assessed by ELISA and cytokine bead array. RESULTS Surface expression of TLR2 was significantly lower on alveolar macrophages than on blood monocytes (1.2 +/- 0.4% vs. 57 +/- 11.1%, relative mean fluorescence intensity [rMFI]: 0.9 +/- 0.1 vs. 3.2 +/- 0.1, p < 0.05). The proportion of TLR4 and TLR9-expressing cells and the rMFIs of TLR4 were comparable between alveolar macrophages and monocytes. The surface expression of TLR9 however, was higher on alveolar macrophages than on monocytes (rMFI, 218.4 +/- 187.3 vs. 4.4 +/- 1.4, p < 0.05) while the intracellular expression of the receptor and the proportion of TLR9 positive cells were similar in both cell types. TLR2, TLR4 and TLR9 mRNA expression was lower in bronchoalveolar cells than in monocytes.Pam3Cys, LPS, and M.tb DNA upregulated TLR2, TLR4 and TLR9 mRNA in both, bronchoalveolar cells and monocytes. Corresponding with the reduced surface and mRNA expression of TLR2, Pam3Cys induced lower production of TNF-alpha, IL-1beta and IL-6 in bronchoalveolar cells than in monocytes. Despite comparable expression of TLR4 on both cell types, LPS induced higher levels of IL-10 in monocytes than in alveolar macrophages. M.tb DNA, the ligand for TLR9, induced similar levels of cytokines in both cell types. CONCLUSION The TLR expression profile of autologous human alveolar macrophages and monocytes is not identical, therefore perhaps contributing to compartmentalized immune responses in the lungs and systemically. These dissimilarities may have important implications for the design and efficacy evaluation of vaccines with TLR-stimulating adjuvants that target the respiratory tract.
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Affiliation(s)
- Esmeralda Juarez
- Departamento de Microbiología, Instituto Nacional de Enfermedades Respiratorias, (Calzada de Tlalpan) México City, (14080), México
| | - Carlos Nuñez
- Servicio de Broncoscopia, Instituto Nacional de Enfermedades Respiratorias, (Calzada de Tlalpan) México City, (14080), México
| | - Eduardo Sada
- Departamento de Microbiología, Instituto Nacional de Enfermedades Respiratorias, (Calzada de Tlalpan) México City, (14080), México
| | - Jerrold J Ellner
- Center for Emerging & Reemerging Pathogens, University of Medicine and Dentistry New Jersey, (S Orange Ave), Newark, (07103), USA
- Department of Medicine, Section of Infectious Diseases, Boston Medical Center (Albany Street), Boston, (02118), USA
| | - Stephan K Schwander
- Center for Emerging & Reemerging Pathogens, University of Medicine and Dentistry New Jersey, (S Orange Ave), Newark, (07103), USA
- Department of Environmental and Occupational Health, University of Medicine and Dentistry New Jersey - School of Public Health (Hoes Lane) Piscataway, (08854), USA
- Center for Global Public Health, University of Medicine and Dentistry New Jersey - School of Public Health (Hoes Lane) Piscataway, (08854), USA
| | - Martha Torres
- Departamento de Microbiología, Instituto Nacional de Enfermedades Respiratorias, (Calzada de Tlalpan) México City, (14080), México
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359
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Smith LC, Ghosh J, Buckley KM, Clow LA, Dheilly NM, Haug T, Henson JH, Li C, Lun CM, Majeske AJ, Matranga V, Nair SV, Rast JP, Raftos DA, Roth M, Sacchi S, Schrankel CS, Stensvåg K. Echinoderm Immunity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 708:260-301. [DOI: 10.1007/978-1-4419-8059-5_14] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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360
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Messier-Solek C, Buckley KM, Rast JP. Highly diversified innate receptor systems and new forms of animal immunity. Semin Immunol 2009; 22:39-47. [PMID: 20022762 DOI: 10.1016/j.smim.2009.11.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Accepted: 11/18/2009] [Indexed: 12/20/2022]
Abstract
Detailed understanding of animal immunity derives almost entirely from investigations of vertebrates, with a smaller, but significant, contribution from studies in fruit flies. This limited phylogenetic scope has artificially polarized the larger view of animal immunity toward the complex adaptive immune systems of vertebrates on the one hand and systems driven by relatively small, stable families of innate receptors of insects on the other. In the past few years analyses of a series of invertebrate deuterostome genome sequences, including those from echinoderms and cephalochordates, sharply modify this view. These findings have far-reaching implications for characterizing the potential range of animal immunity and for inferring the evolutionary pathway that led to vertebrate immune systems.
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Affiliation(s)
- Cynthia Messier-Solek
- Department of Medical Biophysics, University of Toronto, Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, Rm. S126B, Toronto, ON M4N 3M5, Canada.
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361
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Barreiro LB, Quintana-Murci L. From evolutionary genetics to human immunology: how selection shapes host defence genes. Nat Rev Genet 2009; 11:17-30. [PMID: 19953080 DOI: 10.1038/nrg2698] [Citation(s) in RCA: 357] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Pathogens have always been a major cause of human mortality, so they impose strong selective pressure on the human genome. Data from population genetic studies, including genome-wide scans for selection, are providing important insights into how natural selection has shaped immunity and host defence genes in specific human populations and in the human species as a whole. These findings are helping to delineate genes that are important for host defence and to increase our understanding of how past selection has had an impact on disease susceptibility in modern populations. A tighter integration between population genetic studies and immunological phenotype studies is now necessary to reveal the mechanisms that have been crucial for our past and present survival against infection.
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Affiliation(s)
- Luis B Barreiro
- Human Evolutionary Genetics, Institut Pasteur, Centre National de la Recherche Scientifique URA3012, Paris 75015, France
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362
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Abstract
This review article is an attempt to trace the evolution of mast cells (MCs). These immune cells have been identified in all vertebrate classes as single-lobed cells containing variable amounts of membrane-bound secretory granules which store a large series of mediators, namely histamine, proteases, cytokines and growth factors. Other MC features, at least in mammals, are the c-kit receptor for the stem cell factor and the high-affinity receptor, FcepsilonRI, for immunoglobulin E (IgE). The c-kit receptor also has been identified in fish MCs. The FcepsilonRI receptor seems to be a more recent acquisition in MC phylogenesis given that IgE originated in mammalian species. Tryptase and histamine have also been recognized in MCs of teleost fish. Thus, a cell population with the overall characteristics of higher vertebrate MCs is identifiable in the most evolutionarily advanced fish species. Two potential MC progenitors have been identified in ascidians (urochordates which appeared approximately 500 million years ago): the basophil/MC-like granular haemocyte and the test cell. Both contain histamine and heparin, and provide defensive functions. Some granular haemocytes in Arthropoda also closely approximate the ultrastructure of modern MCs. The origin of MCs is probably to be found in a leukocyte ancestor operating in the context of a primitive local innate immunity and involved in phagocytic and killing activity against pathogens. From this type of defensive cell, the MC phylogenetic progenitor evolved into a tissue regulatory and remodelling cell, which was incorporated into the networks of recombinase activating genes (RAG)-mediated adaptive immunity in the Cambrian era, some 550 million years ago. Early MCs probably appeared in the last common ancestor we shared with hagfish, lamprey and sharks about 450-500 million years ago.
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363
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Schikorski D, Cuvillier-Hot V, Boidin-Wichlacz C, Slomianny C, Salzet M, Tasiemski A. Deciphering the Immune Function and Regulation by a TLR of the Cytokine EMAPII in the Lesioned Central Nervous System Using a Leech Model. THE JOURNAL OF IMMUNOLOGY 2009; 183:7119-28. [DOI: 10.4049/jimmunol.0900538] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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364
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Lima PT, Faria VG, Patraquim P, Ramos AC, Feijó JA, Sucena É. Plant-microbe symbioses: new insights into common roots. Bioessays 2009; 31:1233-44. [DOI: 10.1002/bies.200800177] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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365
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Harder J, Franchi L, Muñoz-Planillo R, Park JH, Reimer T, Núñez G. Activation of the Nlrp3 inflammasome by Streptococcus pyogenes requires streptolysin O and NF-kappa B activation but proceeds independently of TLR signaling and P2X7 receptor. THE JOURNAL OF IMMUNOLOGY 2009; 183:5823-9. [PMID: 19812205 DOI: 10.4049/jimmunol.0900444] [Citation(s) in RCA: 182] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Macrophages play a crucial role in the innate immune response against the human pathogen Streptococcus pyogenes, yet the innate immune response against the bacterium is poorly characterized. In the present study, we show that caspase-1 activation and IL-1beta secretion were induced by live, but not killed, S. pyogenes, and required expression of the pore-forming toxin streptolysin O. Using macrophages deficient in inflammasome components, we found that both NLR family pyrin domain-containing 3 (Nlrp3) and apoptosis-associated speck-like protein (Asc) were crucial for caspase-1 activation and IL-1beta secretion, but dispensable for pro-IL-1beta induction, in response to S. pyogenes infection. Conversely, macrophages deficient in the essential TLR adaptors Myd88 and Trif showed normal activation of caspase-1, but impaired induction of pro-IL-1beta and secretion of IL-1beta. Notably, activation of caspase-1 by TLR2 and TLR4 ligands in the presence of streptolysin O required Myd88/Trif, whereas that induced by S. pyogenes was blocked by inhibition of NF-kappaB. Unlike activation of the Nlrp3 inflammasome by TLR ligands, the induction of caspase-1 activation by S. pyogenes did not require exogenous ATP or the P2X7R. In vivo experiments revealed that Nlrp3 was critical for the production of IL-1beta but was not important for survival in a mouse model of S. pyogenes peritoneal infection. These results indicate that caspase-1 activation in response to S. pyogenes infection requires NF-kappaB and the virulence factor streptolysin O, but proceeds independently of P2X7R and TLR signaling.
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Affiliation(s)
- Jürgen Harder
- Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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366
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Raoust E, Balloy V, Garcia-Verdugo I, Touqui L, Ramphal R, Chignard M. Pseudomonas aeruginosa LPS or flagellin are sufficient to activate TLR-dependent signaling in murine alveolar macrophages and airway epithelial cells. PLoS One 2009; 4:e7259. [PMID: 19806220 PMCID: PMC2752798 DOI: 10.1371/journal.pone.0007259] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Accepted: 09/02/2009] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND The human lung is exposed to a large number of airborne pathogens as a result of the daily inhalation of 10,000 liters of air. Innate immunity is thus essential to defend the lungs against these pathogens. This defense is mediated in part through the recognition of specific microbial ligands by Toll-like receptors (TLR) of which there are at least 10 in humans. Pseudomonas aeruginosa is the main pathogen that infects the lungs of cystic fibrosis patients. Based on whole animal experiments, using TLR knockout mice, the control of this bacterium is believed to occur by the recognition of LPS and flagellin by TLRs 2,4 and 5, respectively. METHODOLOGY/PRINCIPAL FINDINGS In the present study, we investigated in vitro the role of these same TLR and ligands, in alveolar macrophage (AM) and epithelial cell (EC) activation. Cellular responses to P. aeruginosa was evaluated by measuring KC, TNF-alpha, IL-6 and G-CSF secretion, four different markers of the innate immune response. AM and EC from WT and TLR2, 4, 5 and MyD88 knockout mice for were stimulated with the wild-type P. aeruginosa or with a mutant devoid of flagellin production. CONCLUSIONS/SIGNIFICANCE The results clearly demonstrate that only two ligand/receptor pairs are necessary for the induction of KC, TNF-alpha, and IL-6 synthesis by P. aeruginosa-activated cells, i.e. TLR2,4/LPS and TLR5/flagellin. Either ligand/receptor pair is sufficient to sense the bacterium and to trigger cell activation, and when both are missing lung EC and AM are unable to produce such a response as were cells from MyD88(-/-) mice.
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Affiliation(s)
- Eloïse Raoust
- Unité de Défense Innée et Inflammation, Institut Pasteur, Paris, France
- INSERM U874, Paris, France
| | - Viviane Balloy
- Unité de Défense Innée et Inflammation, Institut Pasteur, Paris, France
- INSERM U874, Paris, France
| | - Ignacio Garcia-Verdugo
- Unité de Défense Innée et Inflammation, Institut Pasteur, Paris, France
- INSERM U874, Paris, France
| | - Lhousseine Touqui
- Unité de Défense Innée et Inflammation, Institut Pasteur, Paris, France
- INSERM U874, Paris, France
| | - Reuben Ramphal
- Unité de Défense Innée et Inflammation, Institut Pasteur, Paris, France
- INSERM U874, Paris, France
- Department of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Michel Chignard
- Unité de Défense Innée et Inflammation, Institut Pasteur, Paris, France
- INSERM U874, Paris, France
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367
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Using in vivo zebrafish models to understand the biochemical basis of neutrophilic respiratory disease. Biochem Soc Trans 2009; 37:830-7. [PMID: 19614603 DOI: 10.1042/bst0370830] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Neutrophilic inflammation in the lung protects against infectious disease, and usually resolves spontaneously after removal of the inflammatory stimulus. However, much lung disease is caused by a failure of resolution of neutrophilic inflammation. Our laboratory is seeking an understanding of the biochemical basis of inflammation resolution, using the zebrafish model system. Zebrafish larvae are transparent, allowing visualization of GFP (green fluorescent protein)-labelled leucocytes during inflammation in vivo, and they can be readily manipulated by a range of forward and reverse genetic techniques. This combination of advantages makes zebrafish a powerful tool for the study of in vivo inflammatory processes. Using this model, we have visualized the process of inflammation resolution in vivo, and identified a role for apoptosis in this process. In addition, we have performed a forward genetic screen for mutants with defective resolution of inflammation, and reverse genetic experiments examining the influence of candidate genes on inflammation resolution. We have established a platform for screening for compounds with anti-inflammatory activity, which has yielded a number of interesting leads. Looking forward to succeed in the future, we are working at combining mutants, transgenes and pharmacological agents to dissect the biochemical basis of inflammation resolution, and to identify compounds that might be used to treat patients with respiratory disease.
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368
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Muñoz-Planillo R, Franchi L, Miller LS, Núñez G. A critical role for hemolysins and bacterial lipoproteins in Staphylococcus aureus-induced activation of the Nlrp3 inflammasome. THE JOURNAL OF IMMUNOLOGY 2009; 183:3942-8. [PMID: 19717510 DOI: 10.4049/jimmunol.0900729] [Citation(s) in RCA: 264] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The mechanism by which bacterial pathogens activate caspase-1 via Nlrp3 remains poorly understood. In this study, we show that the ability of Staphylococcus aureus, a leading cause of infection in humans, to activate caspase-1 and induce IL-1beta secretion resides in culture supernatants of growing bacteria. Caspase-1 activation induced by S. aureus required alpha-, beta-, and gamma-hemolysins and the host Nlrp3 inflammasome. Mechanistically, alpha- and beta-hemolysins alone did not trigger caspase-1 activation, but they did so in the presence of bacterial lipoproteins released by S. aureus. Notably, caspase-1 activation induced by S. aureus supernatant was independent of the P2X7 receptor and the essential TLR adaptors MyD88 and TIR domain-containing adapter-inducing IFN-beta, but was inhibited by extracellular K(+). These results indicate that S. aureus hemolysins circumvent the requirement of ATP and the P2X7 receptor to induce caspase-1 activation via Nlrp3. Furthermore, these studies revealed that hemolysins promote in the presence of lipoproteins the activation of the Nlrp3 inflammasome.
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Affiliation(s)
- Raúl Muñoz-Planillo
- Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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369
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Wölfle U, Martin S, Emde M, Schempp C. Dermatology in the Darwin anniversary. Part 2: Evolution of the skin-associated immune system. J Dtsch Dermatol Ges 2009; 7:862-9. [PMID: 19725839 DOI: 10.1111/j.1610-0387.2009.07202.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The present review highlights the evolution of the skin-associated immune system from the invertebrates to the vertebrates and man. In the invertebrates a non-specific humoral immune response dominates. It includes antimicrobial peptides, oxidases, lysozyme, agglutinins, coagulins and melanin. The cellular immune system initially consists of undifferentiated mesenchymal stem cells. Later migrating phagocytes and natural killer cells occur. From the fishes on, dendritic cells are present, linking innate and adaptive immune responses. In addition to this unspecific but highly effective immune system, the specific immune response, based on genetic recombination, is present in the vertebrates starting with the chondral fishes. The adaptive immune system possesses unlimited numbers of highly specific antibodies and T-cell receptors, increasingly tissue specific MHC restriction, and cellular memory. Elements of the skin-associated adaptive immune system are first detectable in the teleost fishes in the form of intraepithelial IgM positive lymphocytes and dendritic cells. Moving up to mammals and man, the skin-associated immune system became more and more complex and effective.
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Affiliation(s)
- Ute Wölfle
- Competence Center skintegral, Department of Dermatology, University Medical Center Freiburg, Germany
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370
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Schlosser A, Thomsen T, Moeller JB, Nielsen O, Tornøe I, Mollenhauer J, Moestrup SK, Holmskov U. Characterization of FIBCD1 as an acetyl group-binding receptor that binds chitin. THE JOURNAL OF IMMUNOLOGY 2009; 183:3800-9. [PMID: 19710473 DOI: 10.4049/jimmunol.0901526] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Chitin is a highly acetylated compound and the second most abundant biopolymer in the world next to cellulose. Vertebrates are exposed to chitin both through food ingestion and when infected with parasites, and fungi and chitin modulate the immune response in different directions. We have identified a novel homotetrameric 55-kDa type II transmembrane protein encoded by the FIBCD1 gene and highly expressed in the gastrointestinal tract. The ectodomain of FIBCD1 is characterized by a coiled-coil region, a polycationic region and C-terminal fibrinogen-related domain that by disulfide linkage assembles the protein into tetramers. Functional analysis showed a high-affinity and calcium-dependent binding of acetylated components to the fibrinogen domain, and a function in endocytosis was demonstrated. Screening for ligands revealed that the FIBCD1 is a high-affinity receptor for chitin and chitin fragments. FIBCD1 may play an important role in controlling the exposure of intestine to chitin and chitin fragments, which is of great relevance for the immune defense against parasites and fungi and for immune response modulation.
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Affiliation(s)
- Anders Schlosser
- Medical Biotechnology Center, Pathology, University of Southern Denmark, Odense, Denmark.
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371
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Aliyari R, Ding SW. RNA-based viral immunity initiated by the Dicer family of host immune receptors. Immunol Rev 2009; 227:176-88. [PMID: 19120484 DOI: 10.1111/j.1600-065x.2008.00722.x] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Suppression of viral infection by RNA in a nucleotide sequence homology-dependent manner was first reported in plants in early 1990 s. Studies in the past 15 years have established a completely new RNA-based immune system against viruses that is mechanistically related to RNA silencing or RNA interference (RNAi). This viral immunity begins with recognition of viral double-stranded or structured RNA by the Dicer nuclease family of host immune receptors. In fungi, plants and invertebrates, the viral RNA trigger is processed into small interfering RNAs (siRNAs) to direct specific silencing of the homologous viral genomic and/or messenger RNAs by an RNaseH-like Argonaute protein. Deep sequencing of virus-derived siRNAs indicates that the immunity against viruses with a positive-strand RNA genome is induced by Dicer recognition of dsRNA formed during the initiation of viral progeny (+)RNA synthesis. The RNA-based immune pathway in these organisms overlaps the canonical dsRNA-siRNA pathway of RNAi and may require amplification of viral siRNAs by host RNA-dependent RNA polymerase in plants and nematodes. Production of virus-derived small RNAs is undetectable in mammalian cells infected with RNA viruses. However, infection of mammals with several nucleus-replicating DNA viruses induces production of virus-derived microRNAs capable of silencing host and viral mRNAs as found for viral siRNAs. Remarkably, recent studies indicate that prokaryotes also produce virus-derived small RNAs known as CRISPR RNAs to guide antiviral defense in a manner that has yet to be defined. In this article, we review the recent progress on the identification and mechanism of the key components including viral sensors, viral triggers, effectors, and amplifiers, of the small RNA-directed viral immunity. We also highlight some of the many unresolved questions.
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Affiliation(s)
- Roghiyh Aliyari
- Department of Plant Pathology & Microbiology, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA
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372
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Evolutionary dynamics of human Toll-like receptors and their different contributions to host defense. PLoS Genet 2009; 5:e1000562. [PMID: 19609346 PMCID: PMC2702086 DOI: 10.1371/journal.pgen.1000562] [Citation(s) in RCA: 291] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Accepted: 06/16/2009] [Indexed: 12/11/2022] Open
Abstract
Infectious diseases have been paramount among the threats to health and survival throughout human evolutionary history. Natural selection is therefore expected to act strongly on host defense genes, particularly on innate immunity genes whose products mediate the direct interaction between the host and the microbial environment. In insects and mammals, the Toll-like receptors (TLRs) appear to play a major role in initiating innate immune responses against microbes. In humans, however, it has been speculated that the set of TLRs could be redundant for protective immunity. We investigated how natural selection has acted upon human TLRs, as an approach to assess their level of biological redundancy. We sequenced the ten human TLRs in a panel of 158 individuals from various populations worldwide and found that the intracellular TLRs—activated by nucleic acids and particularly specialized in viral recognition—have evolved under strong purifying selection, indicating their essential non-redundant role in host survival. Conversely, the selective constraints on the TLRs expressed on the cell surface—activated by compounds other than nucleic acids—have been much more relaxed, with higher rates of damaging nonsynonymous and stop mutations tolerated, suggesting their higher redundancy. Finally, we tested whether TLRs have experienced spatially-varying selection in human populations and found that the region encompassing TLR10-TLR1-TLR6 has been the target of recent positive selection among non-Africans. Our findings indicate that the different TLRs differ in their immunological redundancy, reflecting their distinct contributions to host defense. The insights gained in this study foster new hypotheses to be tested in clinical and epidemiological genetics of infectious disease. The detrimental effects of microbial infections have led to the evolution of a variety of host defense mechanisms. A vast array of host innate immunity receptors, critical sensors of viruses, bacteria, and fungi, exist to achieve permanent surveillance of intruding pathogens. The best characterized class of microbial sensors is the Toll-like receptor (TLR) family, which elicits inflammatory and antimicrobial responses after activation by microbial products. Here we investigated how microbes have exerted selective pressure on the human TLR family to gain insights on the extent to which they are functionally important in the immune system. By resequencing the ten TLRs in different worldwide populations, we show that intracellular TLRs—principally specialized in viral recognition—evolve under strong purifying selection, indicating their essential role in host survival, while the remaining TLRs display higher levels of immunological redundancy. However, for this latter group of genes, we also show that mutations altering immune responses have been in some cases beneficial for host survival, as attested by the signature of positive selection favoring a reduced TLR1-mediated response in Europeans. Our findings taken together indicate that the different human TLRs differ in their biological relevance and provide clues to be experimentally tested in clinical, immunological, and epidemiological studies.
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373
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Chicken TLR21 acts as a functional homologue to mammalian TLR9 in the recognition of CpG oligodeoxynucleotides. Mol Immunol 2009; 46:3163-70. [PMID: 19573927 DOI: 10.1016/j.molimm.2009.06.002] [Citation(s) in RCA: 185] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 05/27/2009] [Accepted: 06/01/2009] [Indexed: 11/22/2022]
Abstract
Similar to mammalian species, chickens show marked immunological responses to CpG oligodeoxynucleotides (ODNs) both in vivo and in vitro. In mammals, the receptor for ODNs has been demonstrated to be TLR9; however, an orthologue to mammalian TLR9 is absent in the chicken genome. In this study, chicken TLRs 7, 15 and 21 were expressed in mammalian HEK-293T cells; expression of TLR21 but not TLR7 or 15 resulted in marked NF-kappaB activation upon stimulation with exogenous ODN. This activation was not observed when cells were stimulated by TLR agonists other than ODNs. In addition, responsiveness of the ectopically expressed TLR21 demonstrated similar kinetics of activation as reported for mammalian TLR9 and was dependent on the nucleotide sequence of the ODN. The same ODN specificity was observed for chicken HD11 macrophage when ODN mediated activation was monitored by up-regulation of IL1, IL6 and iNOS transcripts. Furthermore, when TLR21, but not TLR15, was partially silenced in HD11 cells by RNA interference, ODN mediated responses were reduced. TLR21-mediated NF-kappaB activation in HEK-293T cells was inhibited by bafilomycin A suggesting that endosomal maturation is required for TLR21 activation and observations by confocal microscopy and digestion with endoglycosidase H suggest TLR21 localizes to the endoplasmic reticulum (ER) of resting cells. Expression of TLR21 transcripts was found in all chicken tissues examined but was significantly less in the lung and small intestine of newly hatched birds. Two of the leucine rich repeat regions (LRRs) of TLR21 showed homology with a LRR conserved within mammalian TLR9 and implicated in ligand binding. We hypothesize that avian TLR21 plays a similar role to that of mammalian TLR9 and enables recognition of microbial DNA as a danger signal resulting in downstream innate and adaptive immune responses.
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374
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Conner JR, Smirnova II, Poltorak A. A mutation in Irak2c identifies IRAK-2 as a central component of the TLR regulatory network of wild-derived mice. ACTA ACUST UNITED AC 2009; 206:1615-31. [PMID: 19564352 PMCID: PMC2715079 DOI: 10.1084/jem.20090490] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In a phenotypic screen of the wild-derived mouse strain MOLF/Ei, we describe an earlier and more potent toll-like receptor (TLR)–mediated induction of IL-6 transcription compared with the classical inbred strain C57BL/6J. The phenotype correlated with increased activity of the IκB kinase axis as well as p38, but not extracellular signal-regulated kinase or c-Jun N-terminal kinase, mitogen-activated protein kinase (MAPK) phosphorylation. The trait was mapped to the Why1 locus, which contains Irak2, a gene previously implicated as sustaining the late phase of TLR responses. In the MOLF/Ei TLR signaling network, IRAK-2 promotes early nuclear factor κB (NF-κB) activity and is essential for the activation of p38 MAPK. We identify a deletion in the MOLF/Ei promoter of the inhibitory Irak2c gene, leading to an increased ratio of pro- to antiinflammatory IRAK-2 isoforms. These findings demonstrate that IRAK-2 is an essential component of the early TLR response in MOLF/Ei mice and show a distinct pathway of p38 and NF-κB activation in this model organism. In addition, they demonstrate that studies in evolutionarily divergent model organisms are essential to complete dissection of signal transduction pathways.
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Affiliation(s)
- James R Conner
- Department of Pathology, Tufts University School of Medicine, Boston, MA 02111, USA
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375
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Solution structure of the silkworm betaGRP/GNBP3 N-terminal domain reveals the mechanism for beta-1,3-glucan-specific recognition. Proc Natl Acad Sci U S A 2009; 106:11679-84. [PMID: 19561300 DOI: 10.1073/pnas.0901671106] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The beta-1,3-glucan recognition protein (betaGRP)/Gram-negative bacteria-binding protein 3 (GNBP3) is a crucial pattern-recognition receptor that specifically binds beta-1,3-glucan, a component of fungal cell walls. It evokes innate immunity against fungi through activation of the prophenoloxidase (proPO) cascade and Toll pathway in invertebrates. The betaGRP consists of an N-terminal beta-1,3-glucan-recognition domain and a C-terminal glucanase-like domain, with the former reported to be responsible for the proPO cascade activation. This report shows the solution structure of the N-terminal beta-1,3-glucan recognition domain of silkworm betaGRP. Although the N-terminal domain of betaGRP has a beta-sandwich fold, often seen in carbohydrate-binding modules, both NMR titration experiments and mutational analysis showed that betaGRP has a binding mechanism which is distinct from those observed in previously reported carbohydarate-binding domains. Our results suggest that betaGRP is a beta-1,3-glucan-recognition protein that specifically recognizes a triple-helical structure of beta-1,3-glucan.
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376
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Identification of specific and universal virulence factors in Burkholderia cenocepacia strains by using multiple infection hosts. Infect Immun 2009; 77:4102-10. [PMID: 19528212 DOI: 10.1128/iai.00398-09] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Over the past few decades, strains of the Burkholderia cepacia complex have emerged as important pathogens for patients suffering from cystic fibrosis. Identification of virulence factors and assessment of the pathogenic potential of Burkholderia strains have increased the need for appropriate infection models. In previous studies, different infection hosts, including mammals, nematodes, insects, and plants, have been used. At present, however, the extent to which the virulence factors required to infect different hosts overlap is not known. The aim of this study was to analyze the roles of various virulence factors of two closely related Burkholderia cenocepacia strains, H111 and the epidemic strain K56-2, in a multihost pathogenesis system using four different model organisms, namely, Caenorhabditis elegans, Galleria mellonella, the alfalfa plant, and mice or rats. We demonstrate that most of the identified virulence factors are specific for one of the infection models, and only three factors were found to be essential for full pathogenicity in several hosts: mutants defective in (i) quorum sensing, (ii) siderophore production, and (iii) lipopolysaccharide biosynthesis were attenuated in at least three of the infection models and thus may represent promising targets for the development of novel anti-infectives.
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377
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Chang CC, Liu Z, Vlad G, Qin H, Qiao X, Mancini DM, Marboe CC, Cortesini R, Suciu-Foca N. Ig-like transcript 3 regulates expression of proinflammatory cytokines and migration of activated T cells. THE JOURNAL OF IMMUNOLOGY 2009; 182:5208-16. [PMID: 19380766 DOI: 10.4049/jimmunol.0804048] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Ig-like transcript 3 (ILT3), an inhibitory receptor expressed by APC is involved in functional shaping of T cell responses toward a tolerant state. We have previously demonstrated that membrane (m) and soluble (s) ILT3 induce allogeneic tolerance to human islet cells in humanized NOD/SCID mice. Recombinant sILT3 induces the differentiation of CD8(+) T suppressor cells both in vivo and in vitro. To better understand the molecular mechanisms by which ILT3 suppresses immune responses, we have generated ILT3 knockdown (ILT3KD) dendritic cells (DC) and analyzed the phenotypic and functional characteristics of these cells. In this study, we report that silencing of ILT3 expression in DC (ILT3KD DC) increases TLR responsiveness to their specific ligands as reflected in increased synthesis and secretion of proinflammatory cytokines such as IL-1alpha, IL-1beta, and IL-6 and type I IFN. ILT3KD-DC also secretes more CXCL10 and CXCL11 chemokines in response to TLR ligation, thus accelerating T cell migration in diffusion chamber experiments. ILT3KD-DC elicit increased T cell proliferation and synthesis of proinflammatory cytokines IFN-gamma and IL-17A both in MLC and in culture with autologous DC pulsed with CMV protein. ILT3 signaling results in inhibition of NF-kappaB and, to a lesser extent, MAPK p38 pathways in DC. Our results suggest that ILT3 plays a critical role in the control of inflammation.
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Affiliation(s)
- Chih-Chao Chang
- Department of Pathology, Columbia University, NewYork, NY 10032, USA
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378
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Jann OC, King A, Corrales NL, Anderson SI, Jensen K, Ait-ali T, Tang H, Wu C, Cockett NE, Archibald AL, Glass EJ. Comparative genomics of Toll-like receptor signalling in five species. BMC Genomics 2009; 10:216. [PMID: 19432955 PMCID: PMC2689273 DOI: 10.1186/1471-2164-10-216] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Accepted: 05/11/2009] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Over the last decade, several studies have identified quantitative trait loci (QTL) affecting variation of immune related traits in mammals. Recent studies in humans and mice suggest that part of this variation may be caused by polymorphisms in genes involved in Toll-like receptor (TLR) signalling. In this project, we used a comparative approach to investigate the importance of TLR-related genes in comparison with other immunologically relevant genes for resistance traits in five species by associating their genomic location with previously published immune-related QTL regions. RESULTS We report the genomic localisation of TLR1-10 and ten associated signalling molecules in sheep and pig using in-silico and/or radiation hybrid (RH) mapping techniques and compare their positions with their annotated homologues in the human, cattle and mouse whole genome sequences. We also report medium-density RH maps for porcine chromosomes 8 and 13. A comparative analysis of the positions of previously published relevant QTLs allowed the identification of homologous regions that are associated with similar health traits in several species and which contain TLR related and other immunologically relevant genes. Additional evidence was gathered by examining relevant gene expression and association studies. CONCLUSION This comparative genomic approach identified eight genes as potentially causative genes for variations of health related traits. These include susceptibility to clinical mastitis in dairy cattle, general disease resistance in sheep, cattle, humans and mice, and tolerance to protozoan infection in cattle and mice. Four TLR-related genes (TLR1, 6, MyD88, IRF3) appear to be the most likely candidate genes underlying QTL regions which control the resistance to the same or similar pathogens in several species. Further studies are required to investigate the potential role of polymorphisms within these genes.
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Affiliation(s)
- Oliver C Jann
- The Roslin Institute and R(D)SVS, University of Edinburgh, Roslin, Midlothian, Edinburgh, EH25 9PS, UK
| | - Annemarie King
- The Roslin Institute and R(D)SVS, University of Edinburgh, Roslin, Midlothian, Edinburgh, EH25 9PS, UK
| | | | - Susan I Anderson
- The Roslin Institute and R(D)SVS, University of Edinburgh, Roslin, Midlothian, Edinburgh, EH25 9PS, UK
| | - Kirsty Jensen
- The Roslin Institute and R(D)SVS, University of Edinburgh, Roslin, Midlothian, Edinburgh, EH25 9PS, UK
| | - Tahar Ait-ali
- The Roslin Institute and R(D)SVS, University of Edinburgh, Roslin, Midlothian, Edinburgh, EH25 9PS, UK
| | - Haizhou Tang
- The Roslin Institute and R(D)SVS, University of Edinburgh, Roslin, Midlothian, Edinburgh, EH25 9PS, UK
| | - Chunhua Wu
- Department of Animal, Dairy, and Veterinary Sciences, Utah State University, Logan, UT 844322-4700 USA
| | - Noelle E Cockett
- Department of Animal, Dairy, and Veterinary Sciences, Utah State University, Logan, UT 844322-4700 USA
| | - Alan L Archibald
- The Roslin Institute and R(D)SVS, University of Edinburgh, Roslin, Midlothian, Edinburgh, EH25 9PS, UK
| | - Elizabeth J Glass
- The Roslin Institute and R(D)SVS, University of Edinburgh, Roslin, Midlothian, Edinburgh, EH25 9PS, UK
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379
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Ye YH, Chenoweth SF, McGraw EA. Effective but costly, evolved mechanisms of defense against a virulent opportunistic pathogen in Drosophila melanogaster. PLoS Pathog 2009; 5:e1000385. [PMID: 19381251 PMCID: PMC2663048 DOI: 10.1371/journal.ppat.1000385] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Accepted: 03/18/2009] [Indexed: 11/21/2022] Open
Abstract
Drosophila harbor substantial genetic variation for antibacterial defense, and investment in immunity is thought to involve a costly trade-off with life history traits, including development, life span, and reproduction. To understand the way in which insects invest in fighting bacterial infection, we selected for survival following systemic infection with the opportunistic pathogen Pseudomonas aeruginosa in wild-caught Drosophila melanogaster over 10 generations. We then examined genome-wide changes in expression in the selected flies relative to unselected controls, both of which had been infected with the pathogen. This powerful combination of techniques allowed us to specifically identify the genetic basis of the evolved immune response. In response to selection, population-level survivorship to infection increased from 15% to 70%. The evolved capacity for defense was costly, however, as evidenced by reduced longevity and larval viability and a rapid loss of the trait once selection pressure was removed. Counter to expectation, we observed more rapid developmental rates in the selected flies. Selection-associated changes in expression of genes with dual involvement in developmental and immune pathways suggest pleiotropy as a possible mechanism for the positive correlation. We also found that both the Toll and the Imd pathways work synergistically to limit infectivity and that cellular immunity plays a more critical role in overcoming P. aeruginosa infection than previously reported. This work reveals novel pathways by which Drosophila can survive infection with a virulent pathogen that may be rare in wild populations, however, due to their cost. The fruit fly is commonly used as a model organism to understand the mechanistic nature of the immune response to bacterial pathogens. The fly is also commonly used to understand what immunity costs hosts in terms of other traits such as life span and reproductive success. Here, we examine these two questions together in flies selected for improved defense against the bacterium Pseudomonas aeruginosa. We show that selected flies develop from egg to adult more rapidly than unselected flies. It appears that the selected flies invest more heavily in a wing of the immune system that involves engulfment and walling off of invading bacteria. This investment can also explain the shift in developmental rate, as these two biological pathways are controlled by shared sets of genes. These latter two findings are counter to the conventional wisdom and reveal a costly, but effective, means for the fly to circumvent the virulence of Pseudomonas aeruginosa. This bacterium is normally deadly, as it has specific mechanisms to evade the host immune response. Our work is significant for demonstrating a pathway for flies to survive bacterial infection with Pseudomonas aeruginosa and for offering a reason why such a defense is not normally present in wild populations.
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Affiliation(s)
- Yixin H. Ye
- School of Biological Sciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Stephen F. Chenoweth
- School of Biological Sciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Elizabeth A. McGraw
- School of Biological Sciences, The University of Queensland, St. Lucia, Queensland, Australia
- * E-mail:
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380
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Accessory-cell-mediated activation of porcine NK cells by toll-like receptor 7 (TLR7) and TLR8 agonists. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2009; 16:866-78. [PMID: 19369481 DOI: 10.1128/cvi.00035-09] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The induction of innate immune responses by toll-like receptor (TLR) agonists is the subject of intense investigation. In large part, this reflects the potential of such compounds to be effective vaccine adjuvants. For that reason, we analyzed the activation of innate cells in swine by TLR7 and TLR8 agonists. These agonists activated porcine NK cells by increasing gamma interferon (IFN-gamma) expression and perforin storage. The activation of porcine NK cells was mediated by accessory cells, since their depletion resulted in reduced cytotoxicity toward target cells. Accessory cells were stimulated to produce interleukin 12 (IL-12), IL-15, IL-18, and IFN-alpha after treatment with TLR7 or TLR8 agonists. Neutralization of these cytokines reduced but did not completely inhibit the induction of NK cell cytotoxicity. Direct stimulation of NK cells with TLR7 or TLR8 agonists resulted in minimal cytotoxicity but levels of IFN-gamma equivalent to those detected in the presence of accessory cells. Porcine NK cells express both TLR7 and TLR8 mRNAs, and treatment with these TLR agonists induced higher mRNA expression levels of TRAIL and IL-15Ralpha, which may contribute to the activity of NK cells. These data indicate that TLR7 and TLR8 agonists indirectly or directly activate porcine NK cells but that optimum levels of activation require cytokine secretion by accessory cells activated by these compounds. Interestingly, NK cells activated by TLR7 or TLR8 agonists were cytotoxic against foot-and-mouth disease virus (FMDV)-infected cells in vitro, indicating that these TLR agonists may be beneficial as adjuvants to stimulate the innate immunity against FMDV.
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381
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Hishida A, Matsuo K, Goto Y, Mitsuda Y, Hiraki A, Naito M, Wakai K, Tajima K, Hamajima N. Toll-like receptor 4 +3725 G/C polymorphism, Helicobacter pylori seropositivity, and the risk of gastric atrophy and gastric cancer in Japanese. Helicobacter 2009; 14:47-53. [PMID: 19191896 DOI: 10.1111/j.1523-5378.2009.00659.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Toll-like receptor 4 (TLR4) Asp299Gly and Thr399Ile polymorphisms were reported to be a risk factor of gastric carcinoma or its precursors in Caucasian and Indian population, but these polymorphisms are absent in Japanese. We investigated the associations of TLR4+3725 G/C polymorphism, another functional polymorphism of TLR4, with risk of gastric cancer and gastric atrophy in Japanese. MATERIALS AND METHODS Study subjects were 583 histologically diagnosed gastric cancer patients and age- and sex-matched 1592 control outpatients, who visited Aichi Cancer Center Hospital from 2001 to 2005. Serum anti-H. pylori IgG antibody and pepsinogens were measured to evaluate H. pylori infection and gastric atrophy, respectively. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by a logistic model. RESULTS Among the seropositive subjects, the age- and sex-adjusted OR of gastric atrophy was 1.17 (95%CI: 0.91-1.50) for G/C, 1.20 (95%CI: 0.76-1.89) for C/C, and 1.18 (95%CI: 0.93-1.49) for G/C+C/C relative to G/G genotype. The age- and sex-adjusted OR of severe gastric atrophy among H. pylori seropositive subjects was 1.43 (95%CI: 0.99-2.06) for G/C, 1.47 (95%CI: 0.76-2.88) for C/C, and 1.43 (95%CI: 1.01-2.04) for G/C+C/C. The OR of gastric cancer compared with gastric atrophy controls was not statistically significant. CONCLUSION Our study found that TLR4+3725 G/C polymorphism was a risk factor of severe gastric atrophy in H. pylori seropositive Japanese. Our results underscored the significance of the variations in host innate immunity due to TLR4 polymorphism as genetic predispositions to gastric precancerous lesions in Eastern Asian populations with the same backgrounds.
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Affiliation(s)
- Asahi Hishida
- Department of Preventive Medicine/Biostatistics and Medical Decision Making, Nagoya University Graduate School of Medicine, Japan.
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382
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Tan L, Schedl P, Song HJ, Garza D, Konsolaki M. The Toll-->NFkappaB signaling pathway mediates the neuropathological effects of the human Alzheimer's Abeta42 polypeptide in Drosophila. PLoS One 2008; 3:e3966. [PMID: 19088848 PMCID: PMC2597734 DOI: 10.1371/journal.pone.0003966] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Accepted: 11/08/2008] [Indexed: 11/19/2022] Open
Abstract
Alzheimer's (AD) is a progressive neurodegenerative disease that afflicts a significant fraction of older individuals. Although a proteolytic product of the Amyloid precursor protein, the Alphabeta42 polypeptide, has been directly implicated in the disease, the genes and biological pathways that are deployed during the process of Alphabeta42 induced neurodegeneration are not well understood and remain controversial. To identify genes and pathways that mediated Alphabeta42 induced neurodegeneration we took advantage of a Drosophila model for AD disease in which ectopically expressed human Alphabeta42 polypeptide induces cell death and tissue degeneration in the compound eye. One of the genes identified in our genetic screen is Toll (Tl). It encodes the receptor for the highly conserved Tl-->NFkB innate immunity/inflammatory pathway and is a fly homolog of the mammalian Interleukin-1 (Ilk-1) receptor. We found that Tl loss-of-function mutations dominantly suppress the neuropathological effects of the Alphabeta42 polypeptide while gain-of-function mutations that increase receptor activity dominantly enhance them. Furthermore, we present evidence demonstrating that Tl and key downstream components of the innate immunity/inflammatory pathway play a central role in mediating the neuropathological activities of Alphabeta42. We show that the deleterious effects of Alphabeta42 can be suppressed by genetic manipulations of the Tl-->NFkB pathway that downregulate signal transduction. Conversely, manipulations that upregulate signal transduction exacerbate the deleterious effects of Abeta42. Since postmortem studies have shown that the Ilk-1-->NFkB innate immunity pathway is substantially upregulated in the brains of AD patients, the demonstration that the Tl-->NFkB signaling actively promotes the process of Alphabeta42 induced cell death and tissue degeneration in flies points to possible therapeutic targets and strategies.
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Affiliation(s)
- Lihua Tan
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Paul Schedl
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Ho-Juhn Song
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Dan Garza
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Mary Konsolaki
- Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
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383
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Abstract
The innate immune system evolved more than 2 billion years ago to first recognize pathogens then eradicate them. Several distinct defects in this ancient but rapidly responsive element of human immune defense account for the increased incidence of skin infections in atopics. These defects include abnormalities in the physical barrier of the epidermis, alterations in microbial pattern recognition receptors such as toll receptors and nucleotide binding oligomerization domains, and a diminished capacity to increase the expression of antimicrobial peptides during inflammation. Several antimicrobial peptides are affected including; cathelicidin, HBD-2, and HBD-3, which are lower in lesional skin of atopics compared with other inflammatory skin diseases, and dermcidin, which is decreased in sweat. Other defects in the immune defense barrier of atopics include a relative deficiency in plasmacytoid dendritic cells. In the future, understanding the cause of these defects may allow therapeutic intervention to reduce the incidence of infection in atopic individuals and potentially decrease the severity of this disorder.
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384
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Alvarez-Pellitero P. Fish immunity and parasite infections: from innate immunity to immunoprophylactic prospects. Vet Immunol Immunopathol 2008; 126:171-98. [DOI: 10.1016/j.vetimm.2008.07.013] [Citation(s) in RCA: 243] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2008] [Revised: 07/22/2008] [Accepted: 07/25/2008] [Indexed: 10/21/2022]
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385
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Two ways to survive infection: what resistance and tolerance can teach us about treating infectious diseases. Nat Rev Immunol 2008; 8:889-95. [PMID: 18927577 DOI: 10.1038/nri2432] [Citation(s) in RCA: 540] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A host can evolve two types of defence mechanism to increase its fitness when challenged with a pathogen: resistance and tolerance. Immunology is a well-defined field in which the mechanisms behind resistance to infection are dissected. By contrast, the mechanisms behind the ability to tolerate infections are studied in a less methodical manner. In this Opinion, we provide evidence that animals have specific tolerance mechanisms and discuss their potential clinical impact. It is important to distinguish between these two defence mechanisms because they have different pathological and epidemiological effects. An increased understanding of tolerance to pathogen infection could lead to more efficient treatments for infectious diseases and a better description of host-pathogen interactions.
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386
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Dutta G, Zhang P, Liu B. The lipopolysaccharide Parkinson's disease animal model: mechanistic studies and drug discovery. Fundam Clin Pharmacol 2008; 22:453-64. [PMID: 18710400 DOI: 10.1111/j.1472-8206.2008.00616.x] [Citation(s) in RCA: 165] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Research in the last two decades has unveiled an important role for neuroinflammation in the degeneration of the nigrostriatal dopaminergic (DA) pathway that constitutes the pathological basis of the prevailing movement disorder, Parkinson's disease (PD). Neuroinflammation is characterized by the activation of brain glial cells, primarily microglia and astrocytes that release various soluble factors that include free radicals (reactive oxygen and nitrogen species), cytokines, and lipid metabolites. The majority of these glia-derived factors are proinflammatory and neurotoxic and are particularly deleterious to oxidative damage-vulnerable nigral DA neurons. As a proof of concept, various immunologic stimuli have been employed to directly induce glial activation to model DA neurodegeneration in PD. The bacterial endotoxin, lipopolysaccharide (LPS), has been the most extensively utilized glial activator for the induction of inflammatory DA neurodegeneration. In this review, we will summarize the various in vitro and in vivo LPS PD models. Furthermore, we will highlight the contribution of the LPS PD models to the mechanistic studies of PD pathogenesis and the search for neuroprotective agents for the treatment of PD.
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Affiliation(s)
- Garima Dutta
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA
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387
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Host innate immune receptors and beyond: making sense of microbial infections. Cell Host Microbe 2008; 3:352-63. [PMID: 18541212 DOI: 10.1016/j.chom.2008.05.003] [Citation(s) in RCA: 370] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Revised: 05/04/2008] [Accepted: 05/09/2008] [Indexed: 12/12/2022]
Abstract
The complexity of the immune system mirrors its manifold mechanisms of host-microbe interactions. A relatively simplified view was posited after the identification of host innate immune receptors that their distinct mechanisms of sensing "microbial signatures" create unique molecular switches to trigger the immune system. Recently, more sophisticated and cooperative strategies for these receptors have been revealed during receptor-ligand interactions, trafficking, and intra- and intercellular signaling, in order to deal with a diverse range of microbes. Continued mapping of the complex networks of host-microbe interactions may improve our understanding of self/non-self discrimination in immunity and its intervention.
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388
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Kan H, Kim CH, Kwon HM, Park JW, Roh KB, Lee H, Park BJ, Zhang R, Zhang J, Söderhäll K, Ha NC, Lee BL. Molecular control of phenoloxidase-induced melanin synthesis in an insect. J Biol Chem 2008; 283:25316-25323. [PMID: 18628205 DOI: 10.1074/jbc.m804364200] [Citation(s) in RCA: 162] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The melanization reaction induced by activated phenoloxidase in arthropods must be tightly controlled because of excessive formation of quinones and excessive systemic melanization damage to the hosts. However, the molecular mechanism by which phenoloxidase-induced melanin synthesis is regulated in vivo is largely unknown. It is known that the Spätzle-processing enzyme is a key enzyme in the production of cleaved Spätzle from pro-Spätzle in the Drosophila Toll pathway. Here, we provide biochemical evidence that the Tenebrio molitor Spätzle-processing enzyme converts both the 79-kDa Tenebrio prophenoloxidase and Tenebrio clip-domain SPH1 zymogen to an active melanization complex. This complex, consisting of the 76-kDa Tenebrio phenoloxidase and an active form of Tenebrio clip-domain SPH1, efficiently produces melanin on the surface of bacteria, and this activity has a strong bactericidal effect. Interestingly, we found the phenoloxidase-induced melanization reaction to be tightly regulated by Tenebrio prophenoloxidase, which functions as a competitive inhibitor of melanization complex formation. These results demonstrate that the Tenebrio Toll pathway and the melanization reaction share a common serine protease for the regulation of these two major innate immune responses.
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Affiliation(s)
- Hongnan Kan
- National Research Laboratory of Defense Proteins, College of Pharmacy, Busan 609-735, Korea; School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Chan-Hee Kim
- National Research Laboratory of Defense Proteins, College of Pharmacy, Busan 609-735, Korea
| | - Hyun-Mi Kwon
- National Research Laboratory of Defense Proteins, College of Pharmacy, Busan 609-735, Korea
| | - Ji-Won Park
- National Research Laboratory of Defense Proteins, College of Pharmacy, Busan 609-735, Korea
| | - Kyung-Baeg Roh
- National Research Laboratory of Defense Proteins, College of Pharmacy, Busan 609-735, Korea
| | - Hanna Lee
- National Research Laboratory of Defense Proteins, College of Pharmacy, Busan 609-735, Korea
| | - Bum-Joon Park
- Department of Molecular Biology, College of Natural Science, Pusan National University, Busan 609-735, Korea
| | - Rong Zhang
- School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Jinghai Zhang
- School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Kenneth Söderhäll
- Department of Comparative Physiology, Evolutionary Biology Center, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden
| | - Nam-Chul Ha
- National Research Laboratory of Defense Proteins, College of Pharmacy, Busan 609-735, Korea
| | - Bok Luel Lee
- National Research Laboratory of Defense Proteins, College of Pharmacy, Busan 609-735, Korea.
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389
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Abstract
In the past few years the knowledge of insect defense mechanisms against pathogenic microorganisms and parasites has significantly increased on both the molecular and the organismic level. These investigations have led to new concepts of immune protection also relevant for mammals with the identification of the Toll receptor family as an eminent example. This review provides a brief overview of insect strategies to on the one hand defeat bacterial pathogens while on the other hand cooperating with symbiotic bacteria beneficial for the insects.
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Affiliation(s)
- Heike Feldhaar
- Lehrstuhl für Soziobiologie und Verhaltensphysiologie, Biozentrum der Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
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