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Trujillo EN, Flores BA, Romero IV, Moran JA, Leka A, Ramirez AD, Ear J, Mercer F. Complement receptor 3 is required for maximum in vitro trogocytic killing of the parasite Trichomonas vaginalis by human neutrophil-like cells. Parasite Immunol 2024; 46:e13025. [PMID: 38372623 PMCID: PMC11090219 DOI: 10.1111/pim.13025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 01/12/2024] [Accepted: 01/14/2024] [Indexed: 02/20/2024]
Abstract
Trichomonas vaginalis (Tv) is a parasite that causes trichomoniasis, a prevalent sexually-transmitted infection. Neutrophils are found at the site of infection, and can rapidly kill the parasite in vitro, using trogocytosis. However, the specific molecular players in neutrophil killing of Tv are unknown. Here, we show that complement proteins play a role in Tv killing by human neutrophil-like cells (NLCs). Using CRISPR/Cas9, we generated NLCs deficient in each of three complement receptors (CRs) known to be expressed on human neutrophils: CR1, CR3, and CR4. Using in vitro trogocytosis assays, we found that CR3, but not CR1 or CR4 is required for maximum trogocytosis of the parasite by NLCs, with NLCs lacking CR3 demonstrating ~40% reduction in trogocytosis, on average. We also observed a reduction in NLC killing of Tv in CR3 knockout, but not CR1 or CR4 knockout NLCs. On average, NLCs lacking CR3 had ~50% reduction in killing activity. We also used a parallel approach of pre-incubating NLCs with blocking antibodies against CR3, which similarly reduced NLC killing of parasites. These data support a model in which Tv is opsonized by the complement protein iC3b, and bound by neutrophil CR3 receptor, to facilitate trogocytic killing of the parasite.
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Affiliation(s)
- Emma N. Trujillo
- Department of Biological Sciences, California State Polytechnic University, Pomona, California 91768
| | - Barbara A. Flores
- Department of Biological Sciences, California State Polytechnic University, Pomona, California 91768
| | - Isabel V. Romero
- Department of Biological Sciences, California State Polytechnic University, Pomona, California 91768
| | - Jose A. Moran
- Department of Biological Sciences, California State Polytechnic University, Pomona, California 91768
| | - Aljona Leka
- Department of Biological Sciences, California State Polytechnic University, Pomona, California 91768
| | - Ashley D. Ramirez
- Department of Biological Sciences, California State Polytechnic University, Pomona, California 91768
| | - Jason Ear
- Department of Biological Sciences, California State Polytechnic University, Pomona, California 91768
| | - Frances Mercer
- Department of Biological Sciences, California State Polytechnic University, Pomona, California 91768
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2
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Kant S, Liu L, Vazquez-Torres A. The methylglyoxal pathway is a sink for glutathione in Salmonella experiencing oxidative stress. PLoS Pathog 2023; 19:e1011441. [PMID: 37267419 DOI: 10.1371/journal.ppat.1011441] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 05/23/2023] [Indexed: 06/04/2023] Open
Abstract
Salmonella suffer the cytotoxicity of reactive oxygen species generated by the phagocyte NADPH oxidase in the innate host response. Periplasmic superoxide dismutases, catalases and hydroperoxidases detoxify superoxide and hydrogen peroxide (H2O2) synthesized in the respiratory burst of phagocytic cells. Glutathione also helps Salmonella combat the phagocyte NADPH oxidase; however, the molecular mechanisms by which this low-molecular-weight thiol promotes resistance of Salmonella to oxidative stress are currently unknown. We report herein that Salmonella undergoing oxidative stress transcriptionally and functionally activate the methylglyoxal pathway that branches off from glycolysis. Activation of the methylglyoxal pathway consumes a substantial proportion of the glutathione reducing power in Salmonella following exposure to H2O2. The methylglyoxal pathway enables Salmonella to balance glucose utilization with aerobic respiratory outputs. Salmonella take advantage of the metabolic flexibility associated with the glutathione-consuming methylglyoxal pathway to resist reactive oxygen species generated by the enzymatic activity of the phagocyte NADPH oxidase in macrophages and mice. Taken together, glutathione fosters oxidative stress resistance in Salmonella against the antimicrobial actions of the phagocyte NADPH oxidase by promoting the methylglyoxal pathway, an offshoot metabolic adaptation of glycolysis.
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Affiliation(s)
- Sashi Kant
- University of Colorado School of Medicine, Department of Immunology and Microbiology, Aurora, Colorado, United States of America
| | - Lin Liu
- University of Colorado School of Medicine, Department of Immunology and Microbiology, Aurora, Colorado, United States of America
| | - Andres Vazquez-Torres
- University of Colorado School of Medicine, Department of Immunology and Microbiology, Aurora, Colorado, United States of America
- Veterans Affairs, Eastern Colorado Health Care System, Aurora, Colorado, United States of America
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3
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Song M, Kim JS, Liu L, Husain M, Vázquez-Torres A. Antioxidant Defense by Thioredoxin Can Occur Independently of Canonical Thiol-Disulfide Oxidoreductase Enzymatic Activity. Cell Rep 2016; 14:2901-11. [PMID: 26997275 DOI: 10.1016/j.celrep.2016.02.066] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 01/21/2016] [Accepted: 02/15/2016] [Indexed: 01/21/2023] Open
Abstract
The thiol-disulfide oxidoreductase CXXC catalytic domain of thioredoxin contributes to antioxidant defense in phylogenetically diverse organisms. We find that although the oxidoreductase activity of thioredoxin-1 protects Salmonella enterica serovar Typhimurium from hydrogen peroxide in vitro, it does not appear to contribute to Salmonella's antioxidant defenses in vivo. Nonetheless, thioredoxin-1 defends Salmonella from oxidative stress resulting from NADPH phagocyte oxidase macrophage expression during the innate immune response in mice. Thioredoxin-1 binds to the flexible linker, which connects the receiver and effector domains of SsrB, thereby keeping this response regulator in the soluble fraction. Thioredoxin-1, independently of thiol-disulfide exchange, activates intracellular SPI2 gene transcription required for Salmonella resistance to both reactive species generated by NADPH phagocyte oxidase and oxygen-independent lysosomal host defenses. These findings suggest that the horizontally acquired virulence determinant SsrB is regulated post-translationally by ancestrally present thioredoxin.
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Affiliation(s)
- Miryoung Song
- Department of Immunology and Microbiology, University of Colorado School of Medicine, 12800 East 19(th) Avenue, Aurora, CO 80045, USA
| | - Ju-Sim Kim
- Department of Immunology and Microbiology, University of Colorado School of Medicine, 12800 East 19(th) Avenue, Aurora, CO 80045, USA
| | - Lin Liu
- Department of Immunology and Microbiology, University of Colorado School of Medicine, 12800 East 19(th) Avenue, Aurora, CO 80045, USA
| | - Maroof Husain
- Department of Immunology and Microbiology, University of Colorado School of Medicine, 12800 East 19(th) Avenue, Aurora, CO 80045, USA; Division of Molecular and Translational Biomedicine, Department of Anesthesiology and Perioperative Medicine, University of Alabama, Birmingham, 619 South 19(th) Street, Birmingham, AL 35249-6810, USA
| | - Andrés Vázquez-Torres
- Department of Immunology and Microbiology, University of Colorado School of Medicine, 12800 East 19(th) Avenue, Aurora, CO 80045, USA; Veterans Affairs Eastern Colorado Health Care System, 1055 Clermont Street, Denver, CO 80220, USA.
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4
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Abstract
Reactive oxygen species (ROS) are deadly weapons used by phagocytes and other cell types, such as lung epithelial cells, against pathogens. ROS can kill pathogens directly by causing oxidative damage to biocompounds or indirectly by stimulating pathogen elimination by various nonoxidative mechanisms, including pattern recognition receptors signaling, autophagy, neutrophil extracellular trap formation, and T-lymphocyte responses. Thus, one should expect that the inhibition of ROS production promote infection. Increasing evidences support that in certain particular infections, antioxidants decrease and prooxidants increase pathogen burden. In this study, we review the classic infections that are controlled by ROS and the cases in which ROS appear as promoters of infection, challenging the paradigm. We discuss the possible mechanisms by which ROS could promote particular infections. These mechanisms are still not completely clear but include the metabolic effects of ROS on pathogen physiology, ROS-induced damage to the immune system, and ROS-induced activation of immune defense mechanisms that are subsequently hijacked by particular pathogens to act against more effective microbicidal mechanisms of the immune system. The effective use of antioxidants as therapeutic agents against certain infections is a realistic possibility that is beginning to be applied against viruses.
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Affiliation(s)
- Claudia N Paiva
- Departamento de Imunologia, Instituto de Microbiologia , CCS Bloco D, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
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5
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Namdari F, Hurtado-Escobar GA, Abed N, Trotereau J, Fardini Y, Giraud E, Velge P, Virlogeux-Payant I. Deciphering the roles of BamB and its interaction with BamA in outer membrane biogenesis, T3SS expression and virulence in Salmonella. PLoS One 2012; 7:e46050. [PMID: 23144780 PMCID: PMC3489874 DOI: 10.1371/journal.pone.0046050] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 08/27/2012] [Indexed: 11/21/2022] Open
Abstract
The folding and insertion of β-barrel proteins in the outer membrane of Gram-negative bacteria is mediated by the BAM complex, which is composed of the outer membrane protein BamA and four lipoproteins BamB to BamE. In Escherichia coli and/or Salmonella, the BamB lipoprotein is involved in (i) β-barrel protein assembly in the outer membrane, (ii) outer membrane permeability to antibiotics, (iii) the control of the expression of T3SS which are major virulence factors and (iv) the virulence of Salmonella. In E. coli, this protein has been shown to interact directly with BamA. In this study, we investigated the structure-function relationship of BamB in order to assess whether the roles of BamB in these phenotypes were inter-related and whether they require the interaction of BamB with BamA. For this purpose, recombinant plasmids harbouring point mutations in bamB were introduced in a ΔSalmonella bamB mutant. We demonstrated that the residues L173, L175 and R176 are crucial for all the roles of BamB and for the interaction of BamB with BamA. Moreover, the results obtained with a D229A BamB variant, which is unable to immunoprecipitate BamA, suggest that the interaction of BamB with BamA is not absolutely necessary for BamB function in outer-membrane protein assembly, T3SS expression and virulence. Finally, we showed that the virulence defect of the ΔbamB mutant is not related to its increased susceptibility to antimicrobials, as the D227A BamB variant fully restored the virulence of the mutant while having a similar antibiotic susceptibility to the ΔbamB strain. Overall, this study demonstrates that the different roles of BamB are not all inter-related and that L173, L175 and R176 amino-acids are privileged sites for the design of BamB inhibitors that could be used as alternative therapeutics to antibiotics, at least against Salmonella.
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Affiliation(s)
- Fatémeh Namdari
- INRA, UMR1282 Infectiologie et Santé Publique, Nouzilly, France
- Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique, Tours, France
| | - Genaro Alejandro Hurtado-Escobar
- INRA, UMR1282 Infectiologie et Santé Publique, Nouzilly, France
- Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique, Tours, France
| | - Nadia Abed
- INRA, UMR1282 Infectiologie et Santé Publique, Nouzilly, France
- Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique, Tours, France
| | - Jérôme Trotereau
- INRA, UMR1282 Infectiologie et Santé Publique, Nouzilly, France
- Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique, Tours, France
| | - Yann Fardini
- INRA, UMR1282 Infectiologie et Santé Publique, Nouzilly, France
- Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique, Tours, France
| | - Etienne Giraud
- INRA, UMR1282 Infectiologie et Santé Publique, Nouzilly, France
- Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique, Tours, France
| | - Philippe Velge
- INRA, UMR1282 Infectiologie et Santé Publique, Nouzilly, France
- Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique, Tours, France
| | - Isabelle Virlogeux-Payant
- INRA, UMR1282 Infectiologie et Santé Publique, Nouzilly, France
- Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique, Tours, France
- * E-mail: *
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6
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Taub N, Nairz M, Hilber D, Hess MW, Weiss G, Huber LA. The late endosomal adaptor p14 is a macrophage host-defense factor against Salmonella infection. J Cell Sci 2012; 125:2698-708. [PMID: 22427693 DOI: 10.1242/jcs.100073] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The outcome of an infection depends on the balance between host resistance and bacterial virulence. Here, we show that the late endosomal adaptor p14 (also known as LAMTOR2) is one of the components for cellular host defense against the intracellular pathogen Salmonella enterica serovar Typhimurium. During Salmonella infection, the complex of p14 and MP1 is required for the accurately timed transport of Salmonella through the endolysosomal system. Loss of p14 opens a time window that allows Salmonella to populate a replication niche, in which early and late antimicrobial effector systems, comprising NADPH phagocytic oxidase and inducible nitric oxide synthase, respectively, are inappropriately activated. Thus, p14 supports the accurate transport of Salmonella through the endolysosomal system, thereby limiting bacterial replication in both, professional phagocytes and in non-phagocytic cells in vitro, and helps mice to successfully battle Salmonella infection in vivo.
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Affiliation(s)
- Nicole Taub
- Biocenter, Division of Cell Biology, Innsbruck Medical University, Innsbruck 6020, Austria
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7
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Ruby T, McLaughlin L, Gopinath S, Monack D. Salmonella's long-term relationship with its host. FEMS Microbiol Rev 2012; 36:600-15. [PMID: 22335190 DOI: 10.1111/j.1574-6976.2012.00332.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 01/30/2012] [Accepted: 02/07/2012] [Indexed: 12/23/2022] Open
Abstract
Host-adapted strains of Salmonella enterica cause systemic infections and have the ability to persist systemically for long periods of time and pose significant public-health problems. Multidrug-resistant S. enterica serovar Typhi (S. Typhi) and nontyphoidal Salmonella (NTS) are on the increase and are often associated with HIV infection. Chronically infected hosts are often asymptomatic and transmit disease to naïve hosts via fecal shedding of bacteria, thereby serving as a critical reservoir for disease. Salmonella utilizes multiple ways to evade and modulate host innate and adaptive immune responses in order to persist in the presence of a robust immune response. Survival in macrophages and modulation of immune cells migration allow Salmonella to evade various immune responses. The ability of Salmonella to persist depends on a balance between immune responses that lead to the clearance of the pathogen and avoidance of damage to host tissues.
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Affiliation(s)
- Thomas Ruby
- Department of Microbiology and Immunology, Stanford University, Stanford, CA, USA
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8
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Abstract
The mammalian innate immune response provides a barrier against invading pathogens. Innate immune mechanisms are used by the host to respond to a range of bacterial pathogens in an acute and conserved fashion. Host cells express pattern recognition receptors that sense pathogen-associated molecular patterns. After detection, an arsenal of antimicrobial mechanisms is deployed to kill bacteria in infected cells. Innate immunity also stimulates antigen-specific responses mediated by the adaptive immune system. In response, pathogens manipulate host defence mechanisms to survive and eventually replicate. This Review focuses on the control of host innate immune responses by pathogenic intracellular bacteria.
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9
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Subcutaneous vaccination with attenuated Salmonella enterica serovar Choleraesuis C500 expressing recombinant filamentous hemagglutinin and pertactin antigens protects mice against fatal infections with both S. enterica serovar Choleraesuis and Bordetella bronchiseptica. Infect Immun 2008; 76:2157-63. [PMID: 18268026 DOI: 10.1128/iai.01495-07] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Salmonella enterica serovar Choleraesuis strain C500 is a live, attenuated vaccine that has been used in China for over 40 years to prevent piglet paratyphoid. We compared the protective efficacies of subcutaneous (s.c.) and oral vaccination of BALB/c mice with C500 expressing the recombinant filamentous hemagglutinin type I domain and pertactin region 2 domain antigen (rF1P2) of Bordetella bronchiseptica. Protective efficacy against both S. enterica serovar Choleraesuis infection in an oral fatal challenge model and B. bronchiseptica infection in a model of fatal acute pneumonia was evaluated. Both the s.c. and oral vaccines conferred complete protection against fatal infection with the virulent parent S. enterica serovar Choleraesuis strain (C78-1). All 20 mice vaccinated s.c. survived intranasal challenge with four times the 50% lethal dose of virulent B. bronchiseptica (HH0809) compared with 4 of 20 vector-treated controls and 1 of 18 phosphate-buffered saline-treated controls that survived, but no significant protection against HH0809 was observed in orally vaccinated animals. Both the s.c. and oral vaccines elicited rF1P2-specific serum immunoglobulin G (IgG) and IgA antibodies. However, lung homogenates from s.c. vaccinated animals had detectably high levels of rF1P2-specific IgG and IgA; a much lower level of rF1P2-specific IgG was detected in samples from orally vaccinated mice, and the latter showed no evidence of local IgA. Furthermore, a more abundant and longer persistence of vaccine organisms was observed in the lungs of mice immunized s.c. than in those of mice immunized orally. Our results suggest that s.c. rather than oral vaccination is more efficacious in protecting mice from fatal challenge with B. bronchiseptica.
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10
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Abstract
Neutrophils constitute the dominant cell in the circulation that mediates the earliest innate immune human responses to infection. The morbidity and mortality from infection rise dramatically in patients with quantitative or qualitative neutrophil defects, providing clinical confirmation of the important role of normal neutrophils for human health. Neutrophil-dependent anti-microbial activity against ingested microbes represents the collaboration of multiple agents, including those prefabricated during granulocyte development in the bone marrow and those generated de novo following neutrophil activation. Furthermore, neutrophils cooperate with extracellular agents as well as other immune cells to optimally kill and degrade invading microbes. This brief review focuses attention on two examples of the integrated nature of neutrophil-mediated anti-microbial action within the phagosome. The importance and complexity of myeloperoxidase-mediated events illustrate a collaboration of anti-microbial responses that are endogenous to the neutrophil, whereas the synergy between the phagocyte NADPH (nicotinamide adenine dinucleotide phosphate) oxidase and plasma-derived group IIA phospholipase A(2) exemplifies the collective effects of the neutrophil with an exogenous factor to achieve degradation of ingested staphylococci.
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Affiliation(s)
- William M Nauseef
- Inflammation Program, Department of Medicine, University of Iowa, Iowa City, IA 52241, USA.
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11
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Persson J, Vance RE. Genetics-squared: combining host and pathogen genetics in the analysis of innate immunity and bacterial virulence. Immunogenetics 2007; 59:761-78. [PMID: 17874090 DOI: 10.1007/s00251-007-0248-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2007] [Accepted: 08/20/2007] [Indexed: 12/16/2022]
Abstract
The interaction of bacterial pathogens with their hosts' innate immune systems can be extremely complex and is often difficult to disentangle experimentally. Using mouse models of bacterial infections, several laboratories have successfully applied genetic approaches to identify novel host genes required for innate immune defense. In addition, a variety of creative bacterial genetic schemes have been developed to identify key bacterial genes involved in triggering or evading host immunity. In cases where both the host and pathogen are amenable to genetic manipulation, a combination of host and pathogen genetic approaches can be used. Focusing on bacterial infections of mice, this review summarizes the benefits and limitations of applying genetic analysis to the study of host-pathogen interactions. In particular, we consider how prokaryotic and eukaryotic genetic strategies can be combined, or "squared," to yield new insights in host-pathogen biology.
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12
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van Diepen A, Martina CAE, Flierman R, Janssen R, van Dissel JT. Treatment with anti-TNF? does not induce reactivation of latent Salmonella enterica serovar Typhimurium infection in C3H/HeN mice. Scand J Immunol 2007; 65:407-11. [PMID: 17444950 DOI: 10.1111/j.1365-3083.2007.01920.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Therapy with tumour necrosis factor-alpha (TNFalpha)-blocking agents is successful in treating inflammatory disorders, but carries an increased risk of manifest and reactivating infection with intracellular bacteria. In a mouse model of latent Salmonella typhimurium infection, neutralization of TNFalpha did not result in reactivation of infection, suggesting only a minor role for TNFalpha during latency of persistent Salmonella infection.
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Affiliation(s)
- A van Diepen
- Department of Infectious Diseases, Leiden University Medical Center, RC Leiden, The Netherlands
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13
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Sancho-Shimizu V, Malo D. Sequencing, expression, and functional analyses support the candidacy of Ncf2 in susceptibility to Salmonella typhimurium infection in wild-derived mice. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2006; 176:6954-61. [PMID: 16709856 DOI: 10.4049/jimmunol.176.11.6954] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A recessive Salmonella Typhimurium susceptibility locus (immunity to Typhimurium (Ity3) was reported previously on distal mouse chromosome 1 using a cross between C57BL/6J and wild-derived MOLF/Ei mice. This quantitative trait locus is located in a genomic region spanning 84 Mb, rich in candidate genes for which a role in host resistance to Salmonella infection is either known or can be envisioned. In this study, we report the evaluation of neutrophil cytosolic factor 2 (Ncf2) as a candidate Salmonella susceptibility gene for Ity3. Ncf2 encodes p67phox, a subunit of the multiprotein enzyme complex NADPH oxidase, known to be responsible for the generation of superoxides. Congenic mice carrying the Ity3 region from MOLF/Ei, B6.MOLF-Ity/Ity3 were more susceptible to infection compared with control mice heterozygous at Ity3, B6.MOLF-Ity/Ity3(MOLF/B6), confirming the existence of a recessive Salmonella susceptibility locus on distal chromosome 1. Spleen Ncf2 expression levels were lower in infected congenic mice homozygous for the MOLF/Ei allele at Ity3 compared with mice heterozygous at Ity3. C57BL/6J and MOLF/Ei Ncf2 sequence comparisons revealed one nonconservative amino acid change (R394Q) in the functional and highly conserved Phox and Bem1 domain of the protein. Functional analysis revealed that the MOLF/Ei allele had reduced PMA- and Salmonella-induced superoxide induction as compared with their wild-type counterparts ex vivo. The R394Q substitution seems to occur on an amino acid involved in electrostatic interactions with p40phox, crucial in its activation. Moreover, a human mutation in the corresponding R395W, resulting in chronic granulatomous disease, is known to lead to reduced superoxide levels. These results support the candidacy of Ncf2 as the gene underlying Ity3.
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14
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Bignell E, Negrete-Urtasun S, Calcagno AM, Arst HN, Rogers T, Haynes K. Virulence comparisons of Aspergillus nidulans mutants are confounded by the inflammatory response of p47phox-/- mice. Infect Immun 2005; 73:5204-7. [PMID: 16041040 PMCID: PMC1201179 DOI: 10.1128/iai.73.8.5204-5207.2005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
While investigating the requirement for phagosomal alkalinization in the host defense against pulmonary aspergillosis, we observed high morbidity of p47(phox)(-/-) mice infected with pH-insensitive Aspergillus nidulans mutants despite a paucity of fungal growth. Fatal infection also resulted from a normally avirulent p-aminobenzoate auxotroph. This demonstrates that p47(phox)(-/-) murine immunity contributes significantly to A. nidulans lethality. These data have wider implications for microbial virulence studies with p47(phox)(-/-) mice.
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Affiliation(s)
- Elaine Bignell
- Department of Infectious Diseases, Imperial College London, Du Cane Road, London W12 0NN, United Kingdom.
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15
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van Diepen A, van de Gevel JS, Koudijs MM, Ossendorp F, Beekhuizen H, Janssen R, van Dissel JT. Gamma irradiation or CD4+-T-cell depletion causes reactivation of latent Salmonella enterica serovar Typhimurium infection in C3H/HeN mice. Infect Immun 2005; 73:2857-62. [PMID: 15845491 PMCID: PMC1087344 DOI: 10.1128/iai.73.5.2857-2862.2005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Upon infection with Salmonella, a host develops an immune response to limit bacterial growth and kill and eliminate the pathogen. Salmonella has evolved mechanisms to remain dormant within the body, only to reappear (reactivate) at a later time when the immune system is abated. We have developed an in vivo model for studying reactivation of Salmonella enterica serovar Typhimurium infection in mice. Upon subcutaneous infection, C3H/HeN (Ity(r)) mice showed an increase in bacterial numbers in livers and spleens, which reached a peak on day 19. After full recovery from the infection, these mice were irradiated or depleted of CD4(+) T cells. The mice displayed a secondary infection peak in livers and spleens with a course similar to that of the primary infection. We concluded that CD4(+) T cells are involved in active suppression of S. enterica serovar Typhimurium during latency. The role of CD4(+) T cells during primary infection with S. enterica serovar Typhimurium is well established. This is the first study to describe a role of CD4(+) T cells during the latent phase of S. enterica serovar Typhimurium infection.
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Affiliation(s)
- Angela van Diepen
- Department of Infectious Diseases, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands
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16
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Ng VH, Cox JS, Sousa AO, MacMicking JD, McKinney JD. Role of KatG catalase-peroxidase in mycobacterial pathogenesis: countering the phagocyte oxidative burst. Mol Microbiol 2004; 52:1291-302. [PMID: 15165233 DOI: 10.1111/j.1365-2958.2004.04078.x] [Citation(s) in RCA: 226] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Reactive nitrogen species (RNS) play an essential role in host defence against Mycobacterium tuberculosis (MTB) in the mouse model of tuberculosis (TB), as evidenced by the increased susceptibility of mice deficient in the inducible isoform of nitric oxide synthase (NOS2). In contrast, the role of reactive oxygen species (ROS) in protection against MTB is less clear, and mice defective in the ROS-generating phagocyte NADPH oxidase (Phox) are relatively resistant. This suggests that MTB might possess efficient mechanisms to evade or counter the phagocyte oxidative burst, effectively masking the impact of this host defence mechanism. In order to assess the role of ROS detoxification pathways in MTB virulence, we generated a katG null mutant of MTB, deficient in the KatG catalase-peroxidase-peroxynitritase, and evaluated the mutant's ability to replicate and persist in macrophages and mice. Although markedly attenuated in wild-type C57Bl/6 mice and NOS2(-/-) mice, the DeltakatG MTB strain was indistinguishable from wild-type MTB in its ability to replicate and persist in gp91(Phox-/-) mice lacking the gp91 subunit of NADPH oxidase. Similar observations were made with murine bone marrow macrophages infected ex vivo: growth of the DeltakatG MTB strain was impaired in macrophages from C57Bl/6 and NOS2(-/-) mice, but indistinguishable from wild-type MTB in gp91(Phox-/-) macrophages. These results indicate that the major role of KatG in MTB pathogenesis is to catabolize the peroxides generated by the phagocyte NADPH oxidase; in the absence of this host antimicrobial mechanism, KatG is apparently dispensable.
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Affiliation(s)
- Vincent H Ng
- Laboratory of Infection Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA
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van der Straaten T, Zulianello L, van Diepen A, Granger DL, Janssen R, van Dissel JT. Salmonella enterica serovar Typhimurium RamA, intracellular oxidative stress response, and bacterial virulence. Infect Immun 2004; 72:996-1003. [PMID: 14742546 PMCID: PMC321585 DOI: 10.1128/iai.72.2.996-1003.2004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Escherichia coli and Salmonella enterica serovar Typhimurium have evolved genetic systems, such as the soxR/S and marA regulons, to detoxify reactive oxygen species, like superoxide, which are formed as by-products of metabolism. Superoxide also serves as a microbicidal effector mechanism of the host's phagocytes. Here, we investigate whether regulatory genes other than soxR/S and marA are active in response to oxidative stress in Salmonella and may function as virulence determinants. We identified a bacterial gene, which was designated ramA (342 bp) and mapped at 13.1 min on the Salmonella chromosome, that, when overexpressed on a plasmid in E. coli or Salmonella, confers a pleiotropic phenotype characterized by increased resistance to the redox-cycling agent menadione and to multiple unrelated antibiotics. The ramA gene is present in Salmonella serovars but is absent in E. coli. The gene product displays 37 to 52% homology to the transcriptional activators soxR/S and marA and 80 to 100% identity to a multidrug resistance gene in Klebsiella pneumoniae and Salmonella enterica serovar Paratyphi A. Although a ramA soxR/S double null mutant is highly susceptible to intracellular superoxide generated by menadione and displays decreased Mn-superoxide dismutase activity, intracellular survival of this mutant within macrophage-like RAW 264.7 cells and in vivo replication in the spleens in Ityr mice are not affected. We concluded that despite its role in the protective response of the bacteria to oxidative stress in vitro, the newly identified ramA gene, together with soxR/S, does not play a role in initial replication of Salmonella in the organs of mice.
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Affiliation(s)
- Tahar van der Straaten
- Department of Infectious Diseases, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
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Brenot A, King KY, Janowiak B, Griffith O, Caparon MG. Contribution of glutathione peroxidase to the virulence of Streptococcus pyogenes. Infect Immun 2004; 72:408-13. [PMID: 14688122 PMCID: PMC344014 DOI: 10.1128/iai.72.1.408-413.2004] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Glutathione peroxidases are widespread among eukaryotic organisms and function as a major defense against hydrogen peroxide and organic peroxides. However, glutathione peroxidases are not well studied among prokaryotic organisms and have not previously been shown to promote bacterial virulence. Recently, a gene with homology to glutathione peroxidase was shown to contribute to the antioxidant defenses of Streptococcus pyogenes (group A streptococcus). Since this bacterium causes numerous suppurative diseases that require it to thrive in highly inflamed tissue, it was of interest to determine if glutathione peroxidase is important for virulence. In this study, we report that GpoA glutathione peroxidase is the major glutathione peroxidase in S. pyogenes and is essential for S. pyogenes pathogenesis in several murine models that mimic different aspects of streptococcal suppurative disease. In contrast, glutathione peroxidase is not essential for virulence in a zebrafish model of streptococcal myositis, a disease characterized by the absence of an inflammatory cell infiltrate. Taken together, these data suggest that S. pyogenes requires glutathione peroxidase to adapt to oxidative stress that accompanies an inflammatory response, and the data provide the first demonstration of a role for glutathione peroxidase in bacterial virulence. The fact that genes encoding putative glutathione peroxidases are found in the genomes of many pathogenic bacterial species suggests that glutathione peroxidase may have a general role in bacterial pathogenesis.
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Affiliation(s)
- Audrey Brenot
- Department of Molecular Microbiology, Center for Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri 63110-1093, USA
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Janssen R, van der Straaten T, van Diepen A, van Dissel JT. Responses to reactive oxygen intermediates and virulence of Salmonella typhimurium. Microbes Infect 2003; 5:527-34. [PMID: 12758282 DOI: 10.1016/s1286-4579(03)00069-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Salmonella typhimurium is an intracellular pathogen that can survive and replicate in macrophages. One of the host defense mechanisms that S. typhimurium encounters upon infection is superoxide produced by the phagocytes' NADPH-oxidase. Salmonella has evolved numerous ways of coping with superoxide in the extracellular environment. In addition, Salmonella has to defend itself against superoxide produced as a by-product of aerobic respiration. Over the last decade, research on bacterial mutants has led to the identification of Salmonella strains that differ from their parental strain in susceptibility to superoxide in vitro. However, the consequences of such mutations for bacterial virulence are highly variable, indicating that superoxide sensitivity per se is not a characteristic that renders Salmonella less virulent. By discussing various bacterial mutants classified according to their in vitro sensitivity to superoxide, we will exemplify the complex mechanisms that Salmonella has evolved to cope with superoxide stress.
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Affiliation(s)
- Riny Janssen
- Department of Infectious Diseases, C5-P, Leiden University Medical Center, P.O. Box 9600, 2300 RC, Leiden, The Netherlands.
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Linehan SA, Holden DW. The interplay between Salmonella typhimurium and its macrophage host--what can it teach us about innate immunity? Immunol Lett 2003; 85:183-92. [PMID: 12527226 DOI: 10.1016/s0165-2478(02)00227-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Salmonella enterica sv. Typhimurium (S. typhimurium) is a genetically tractable, facultative intracellular pathogen, whose capacity to cause systemic disease in mice depends upon its ability to survive and replicate within macrophages. The identification of Salmonella mutants that lack this activity, has provided a tool with which to dissect the mechanisms used by Salmonella to establish a permissive niche, and identify host activities which it must overcome in order to achieve this. Salmonella actively maintains itself within an intracellular vacuole, thereby shielding itself from an antibacterial activity of host macrophage cytosol. Salmonella controls the maturation of its vacuole, segregating itself from the macrophage degradative pathway. Like several other pathogens, Salmonella reduces the effectiveness of bacteriocidal and bacteriostatic free radicals generated by macrophages, by synthesising enzymes and products that counteract them. Recent evidence indicates that Salmonella also avoids free radical-dependent macrophage antimicrobial mechanisms by more novel means. Here, we review recent studies of the interplay between pathogen and host, with particular emphasis on those areas that suggest new facets to the cell biology of macrophages, and their innate immune functions.
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Affiliation(s)
- Sheena A Linehan
- The Department of Infectious Diseases, Centre for Molecular Microbiology and Infection, Imperial College of Science, Technology and Medicine, The Flowers Building, Armstrong Road, London SW7 2AZ, UK.
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