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Calderon-Gonzalez R, Dumigan A, Sá-Pessoa J, Kissenpfennig A, Bengoechea JA. In vivo single-cell high-dimensional mass cytometry analysis to track the interactions between Klebsiella pneumoniae and myeloid cells. PLoS Pathog 2024; 20:e1011900. [PMID: 38578798 PMCID: PMC11023633 DOI: 10.1371/journal.ppat.1011900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 04/17/2024] [Accepted: 03/18/2024] [Indexed: 04/07/2024] Open
Abstract
In vivo single-cell approaches have transformed our understanding of the immune populations in tissues. Mass cytometry (CyTOF), that combines the resolution of mass spectrometry with the ability to conduct multiplexed measurements of cell molecules at the single cell resolution, has enabled to resolve the diversity of immune cell subsets, and their heterogeneous functionality. Here we assess the feasibility of taking CyTOF one step further to immuno profile cells while tracking their interactions with bacteria, a method we term Bac-CyTOF. We focus on the pathogen Klebsiella pneumoniae interrogating the pneumonia mouse model. Using Bac-CyTOF, we unveil the atlas of immune cells of mice infected with a K. pneumoniae hypervirulent strain. The atlas is characterized by a decrease in the populations of alveolar and monocyte-derived macrophages. Conversely, neutrophils, and inflammatory monocytes are characterized by an increase in the subpopulations expressing markers of less active cells such as the immune checkpoint PD-L1. These are the cells infected. We show that the type VI secretion system (T6SS) contributes to shape the lung immune landscape. The T6SS governs the interaction with monocytes/macrophages by shifting Klebsiella from alveolar macrophages to interstitial macrophages and limiting the infection of inflammatory monocytes. The lack of T6SS results in an increase of cells expressing markers of active cells, and a decrease in the subpopulations expressing PD-L1. By probing Klebsiella, and Acinetobacter baumannii strains with limited ability to survive in vivo, we uncover that a heightened recruitment of neutrophils, and relative high levels of alveolar macrophages and eosinophils and the recruitment of a characteristic subpopulation of neutrophils are features of mice clearing infections. We leverage Bac-CyTOF-generated knowledge platform to investigate the role of the DNA sensor STING in Klebsiella infections. sting-/- infected mice present features consistent with clearing the infection including the reduced levels of PD-L1. STING absence facilitates Klebsiella clearance.
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Affiliation(s)
- Ricardo Calderon-Gonzalez
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen’s University Belfast, Belfast, United Kingdom
| | - Amy Dumigan
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen’s University Belfast, Belfast, United Kingdom
| | - Joana Sá-Pessoa
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen’s University Belfast, Belfast, United Kingdom
| | - Adrien Kissenpfennig
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen’s University Belfast, Belfast, United Kingdom
| | - José A. Bengoechea
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen’s University Belfast, Belfast, United Kingdom
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2
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Penny J, Arefian M, Schroeder GN, Bengoechea JA, Collins BC. A gas phase fractionation acquisition scheme integrating ion mobility for rapid diaPASEF library generation. Proteomics 2023; 23:e2200038. [PMID: 36876969 DOI: 10.1002/pmic.202200038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 03/01/2023] [Accepted: 03/01/2023] [Indexed: 03/07/2023]
Abstract
Data independent acquisition (DIA/SWATH) MS is a primary strategy in quantitative proteomics. diaPASEF is a recent adaptation using trapped ion mobility spectrometry (TIMS) to improve selectivity/sensitivity. Complex DIA spectra are typically analyzed with reference to spectral libraries. The best-established method for generating libraries uses offline fractionation to increase depth of coverage. More recently strategies for spectral library generation based on gas phase fractionation (GPF), where a representative sample is injected serially using narrow DIA windows that cover different mass ranges of the complete precursor space, have been introduced that performed comparably to deep offline fractionation-based libraries. We investigated whether an analogous GPF-based approach that accounts for the ion mobility (IM) dimension is useful for the analysis of diaPASEF data. We developed a rapid library generation approach using an IM-GPF acquisition scheme in the m/z versus 1/K0 space requiring seven injections of a representative sample and compared this with libraries generated by direct deconvolution-based analysis of diaPASEF data or by deep offline fractionation. We found that library generation by IM-GPF outperformed direct library generation from diaPASEF and had performance approaching that of the deep library. This establishes the IM-GPF scheme as a pragmatic approach to rapid library generation for analysis of diaPASEF data.
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Affiliation(s)
- Jack Penny
- School of Biological Sciences, Queen's University of Belfast, Belfast, UK
| | - Mohammad Arefian
- School of Biological Sciences, Queen's University of Belfast, Belfast, UK
| | - Gunnar N Schroeder
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - José A Bengoechea
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - Ben C Collins
- School of Biological Sciences, Queen's University of Belfast, Belfast, UK
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3
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Coya JM, Fraile-Ágreda V, de Tapia L, García-Fojeda B, Sáenz A, Bengoechea JA, Kronqvist N, Johansson J, Casals C. Cooperative action of SP-A and its trimeric recombinant fragment with polymyxins against Gram-negative respiratory bacteria. Front Immunol 2022; 13:927017. [PMID: 36159837 PMCID: PMC9493720 DOI: 10.3389/fimmu.2022.927017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Accepted: 08/10/2022] [Indexed: 11/19/2022] Open
Abstract
The exploration of therapies combining antimicrobial lung proteins and conventional antibiotics is important due to the growing problem of multidrug-resistant bacteria. The aim of this study was to investigate whether human SP-A and a recombinant trimeric fragment (rfhSP-A) have cooperative antimicrobial activity with antibiotics against pathogenic Gram-negative bacteria. We found that SP-A bound the cationic peptide polymyxin B (PMB) with an apparent dissociation constant (K D) of 0.32 ± 0.04 µM. SP-A showed synergistic microbicidal activity with polymyxin B and E, but not with other antibiotics, against three SP-A-resistant pathogenic bacteria: Klebsiella pneumoniae, non-typable Haemophilus influenzae (NTHi), and Pseudomonas aeruginosa. SP-A was not able to bind to K. pneumoniae, NTHi, or to mutant strains thereof expressing long-chain lipopolysaccharides (or lipooligosaccharides) and/or polysaccharide capsules. In the presence of PMB, SP-A induced the formation of SP-A/PMB aggregates that enhance PMB-induced bacterial membrane permeabilization. Furthermore, SP-A bound to a molecular derivative of PMB lacking the acyl chain (PMBN) with a K D of 0.26 ± 0.02 μM, forming SP-A/PMBN aggregates. PMBN has no bactericidal activity but can bind to the outer membrane of Gram-negative bacteria. Surprisingly, SP-A and PMBN showed synergistic bactericidal activity against Gram-negative bacteria. Unlike native supratrimeric SP-A, the trimeric rfhSP-A fragment had small but significant direct bactericidal activity against K. pneumoniae, NTHi, and P. aeruginosa. rfhSP-A did not bind to PMB under physiological conditions but acted additively with PMB and other antibiotics against these pathogenic bacteria. In summary, our results significantly improve our understanding of the antimicrobial actions of SP-A and its synergistic action with PMB. A peptide based on SP-A may aid the therapeutic use of PMB, a relatively cytotoxic antibiotic that is currently being reintroduced into clinics due to the global problem of antibiotic resistance.
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Affiliation(s)
- Juan Manuel Coya
- Department of Biochemistry and Molecular Biology, Complutense University of Madrid, Madrid, Spain
| | - Víctor Fraile-Ágreda
- Department of Biochemistry and Molecular Biology, Complutense University of Madrid, Madrid, Spain
| | - Lidia de Tapia
- Department of Biochemistry and Molecular Biology, Complutense University of Madrid, Madrid, Spain
| | - Belén García-Fojeda
- Department of Biochemistry and Molecular Biology, Complutense University of Madrid, Madrid, Spain
| | - Alejandra Sáenz
- Department of Biochemistry and Molecular Biology, Complutense University of Madrid, Madrid, Spain
| | - José A. Bengoechea
- Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast, Belfast, United Kingdom
| | - Nina Kronqvist
- Department of Biosciences and Nutrition, Neo, Karolinska Institutet, Huddinge, Sweden
| | - Jan Johansson
- Department of Biosciences and Nutrition, Neo, Karolinska Institutet, Huddinge, Sweden
| | - Cristina Casals
- Department of Biochemistry and Molecular Biology, Complutense University of Madrid, Madrid, Spain
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4
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Feriotti C, Sá-Pessoa J, Calderón-González R, Gu L, Morris B, Sugisawa R, Insua JL, Carty M, Dumigan A, Ingram RJ, Kissenpfening A, Bowie AG, Bengoechea JA. Klebsiella pneumoniae hijacks the Toll-IL-1R protein SARM1 in a type I IFN-dependent manner to antagonize host immunity. Cell Rep 2022; 40:111167. [PMID: 35947948 PMCID: PMC9638020 DOI: 10.1016/j.celrep.2022.111167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 05/18/2022] [Accepted: 07/14/2022] [Indexed: 02/06/2023] Open
Abstract
Many bacterial pathogens antagonize host defense responses by translocating effector proteins into cells. It remains an open question how those pathogens not encoding effectors counteract anti-bacterial immunity. Here, we show that Klebsiella pneumoniae exploits the evolutionary conserved innate protein SARM1 to regulate negatively MyD88- and TRIF-governed inflammation, and the activation of the MAP kinases ERK and JNK. SARM1 is required for Klebsiella induction of interleukin-10 (IL-10) by fine-tuning the p38-type I interferon (IFN) axis. SARM1 inhibits the activation of Klebsiella-induced absent in melanoma 2 inflammasome to limit IL-1β production, suppressing further inflammation. Klebsiella exploits type I IFNs to induce SARM1 in a capsule and lipopolysaccharide O-polysaccharide-dependent manner via the TLR4-TRAM-TRIF-IRF3-IFNAR1 pathway. Absence of SARM1 reduces the intracellular survival of K. pneumoniae in macrophages, whereas sarm1-deficient mice control the infection. Altogether, our results illustrate an anti-immunology strategy deployed by a human pathogen. SARM1 inhibition will show a beneficial effect to treat Klebsiella infections. SARM1 is an evolutionary conserved innate immune protein with a TIR domain Klebsiella pneumoniae induces SARM1 to limit inflammation, and to induce IL-10 SARM1 inhibits the action of AIM2 inflammasome to limit IL-1β production In vivo, absence of SARM1 facilitates the clearance of Klebsiella pneumoniae
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Affiliation(s)
- Claudia Feriotti
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast, UK
| | - Joana Sá-Pessoa
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast, UK
| | - Ricardo Calderón-González
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast, UK
| | - Lili Gu
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Brenda Morris
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast, UK
| | - Ryoichi Sugisawa
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Jose L Insua
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast, UK
| | - Michael Carty
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Amy Dumigan
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast, UK
| | - Rebecca J Ingram
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast, UK
| | - Adrien Kissenpfening
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast, UK
| | - Andrew G Bowie
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - José A Bengoechea
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast, UK.
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5
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Bengoechea JA, Sa Pessoa J. Klebsiella pneumoniae infection biology: living to counteract host defences. FEMS Microbiol Rev 2019; 43:123-144. [PMID: 30452654 PMCID: PMC6435446 DOI: 10.1093/femsre/fuy043] [Citation(s) in RCA: 256] [Impact Index Per Article: 51.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 11/16/2018] [Indexed: 12/26/2022] Open
Abstract
Klebsiella species cause a wide range of diseases including pneumonia, urinary tract infections (UTIs), bloodstream infections and sepsis. These infections are particularly a problem among neonates, elderly and immunocompromised individuals. Klebsiella is also responsible for a significant number of community-acquired infections. A defining feature of these infections is their morbidity and mortality, and the Klebsiella strains associated with them are considered hypervirulent. The increasing isolation of multidrug-resistant strains has significantly narrowed, or in some settings completely removed, the therapeutic options for the treatment of Klebsiella infections. Not surprisingly, this pathogen has then been singled out as an 'urgent threat to human health' by several organisations. This review summarises the tremendous progress that has been made to uncover the sophisticated immune evasion strategies of K. pneumoniae. The co-evolution of Klebsiella in response to the challenge of an activated immune has made Klebsiella a formidable pathogen exploiting stealth strategies and actively suppressing innate immune defences to overcome host responses to survive in the tissues. A better understanding of Klebsiella immune evasion strategies in the context of the host-pathogen interactions is pivotal to develop new therapeutics, which can be based on antagonising the anti-immune strategies of this pathogen.
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Affiliation(s)
- José A Bengoechea
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast BT9 7BL, UK
| | - Joana Sa Pessoa
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast BT9 7BL, UK
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6
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Jiang L, Lin J, Taggart CC, Bengoechea JA, Scott CJ. Nanodelivery strategies for the treatment of multidrug-resistant bacterial infections. J Interdiscip Nanomed 2018; 3:111-121. [PMID: 30443410 PMCID: PMC6220773 DOI: 10.1002/jin2.48] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 06/27/2018] [Accepted: 07/10/2018] [Indexed: 12/15/2022]
Abstract
One of the most important health concerns in society is the development of nosocomial infections caused by multidrug-resistant pathogens. The purpose of this review is to discuss the issues in current antibiotic therapies and the ongoing progress of developing new strategies for the treatment of ESKAPE pathogen infections, which is acronymized for Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species. We not only examine the current issues caused by multidrug resistance but we also examine the barrier effects such as biofilm and intracellular localization exploited by these pathogens to avoid antibiotic exposure. Recent innovations in nanomedicine approaches and antibody antibiotic conjugates are reviewed as potential novel approaches for the treatment of bacterial infection, which ultimately may expand the useful life span of current antibiotics.
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Affiliation(s)
- Lai Jiang
- Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical SciencesQueen's University BelfastBelfastUK
| | - Jia Lin
- School of PharmacyQueen's University BelfastBelfastUK
| | - Clifford C. Taggart
- Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical SciencesQueen's University BelfastBelfastUK
| | - José A. Bengoechea
- Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical SciencesQueen's University BelfastBelfastUK
| | - Christopher J. Scott
- Centre for Cancer Research and Cell Biology, School of Medicine, Dentistry and Biomedical SciencesQueen's University BelfastBelfastUK
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7
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Conde-Álvarez R, Palacios-Chaves L, Gil-Ramírez Y, Salvador-Bescós M, Bárcena-Varela M, Aragón-Aranda B, Martínez-Gómez E, Zúñiga-Ripa A, de Miguel MJ, Bartholomew TL, Hanniffy S, Grilló MJ, Vences-Guzmán MÁ, Bengoechea JA, Arce-Gorvel V, Gorvel JP, Moriyón I, Iriarte M. Identification of lptA, lpxE, and lpxO, Three Genes Involved in the Remodeling of Brucella Cell Envelope. Front Microbiol 2018; 8:2657. [PMID: 29375522 PMCID: PMC5767591 DOI: 10.3389/fmicb.2017.02657] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 12/20/2017] [Indexed: 12/19/2022] Open
Abstract
The brucellae are facultative intracellular bacteria that cause a worldwide extended zoonosis. One of the pathogenicity mechanisms of these bacteria is their ability to avoid rapid recognition by innate immunity because of a reduction of the pathogen-associated molecular pattern (PAMP) of the lipopolysaccharide (LPS), free-lipids, and other envelope molecules. We investigated the Brucella homologs of lptA, lpxE, and lpxO, three genes that in some pathogens encode enzymes that mask the LPS PAMP by upsetting the core-lipid A charge/hydrophobic balance. Brucella lptA, which encodes a putative ethanolamine transferase, carries a frame-shift in B. abortus but not in other Brucella spp. and phylogenetic neighbors like the opportunistic pathogen Ochrobactrum anthropi. Consistent with the genomic evidence, a B. melitensis lptA mutant lacked lipid A-linked ethanolamine and displayed increased sensitivity to polymyxin B (a surrogate of innate immunity bactericidal peptides), while B. abortus carrying B. melitensis lptA displayed increased resistance. Brucella lpxE encodes a putative phosphatase acting on lipid A or on a free-lipid that is highly conserved in all brucellae and O. anthropi. Although we found no evidence of lipid A dephosphorylation, a B. abortus lpxE mutant showed increased polymyxin B sensitivity, suggesting the existence of a hitherto unidentified free-lipid involved in bactericidal peptide resistance. Gene lpxO putatively encoding an acyl hydroxylase carries a frame-shift in all brucellae except B. microti and is intact in O. anthropi. Free-lipid analysis revealed that lpxO corresponded to olsC, the gene coding for the ornithine lipid (OL) acyl hydroxylase active in O. anthropi and B. microti, while B. abortus carrying the olsC of O. anthropi and B. microti synthesized hydroxylated OLs. Interestingly, mutants in lptA, lpxE, or olsC were not attenuated in dendritic cells or mice. This lack of an obvious effect on virulence together with the presence of the intact homolog genes in O. anthropi and B. microti but not in other brucellae suggests that LptA, LpxE, or OL β-hydroxylase do not significantly alter the PAMP properties of Brucella LPS and free-lipids and are therefore not positively selected during the adaptation to intracellular life.
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Affiliation(s)
- Raquel Conde-Álvarez
- Universidad de Navarra, Facultad de Medicina, Departamento de Microbiología y Parasitología, Instituto de Salud Tropical (ISTUN) e Instituto de Investigación Sanitaria de Navarra (IdISNA), Pamplona, Spain
| | - Leyre Palacios-Chaves
- Instituto de Agrobiotecnología, Consejo Superior de Investigaciones Científicas - Universidad Pública de Navarra - Gobierno de Navarra, Pamplona, Spain
| | - Yolanda Gil-Ramírez
- Universidad de Navarra, Facultad de Medicina, Departamento de Microbiología y Parasitología, Instituto de Salud Tropical (ISTUN) e Instituto de Investigación Sanitaria de Navarra (IdISNA), Pamplona, Spain
| | - Miriam Salvador-Bescós
- Universidad de Navarra, Facultad de Medicina, Departamento de Microbiología y Parasitología, Instituto de Salud Tropical (ISTUN) e Instituto de Investigación Sanitaria de Navarra (IdISNA), Pamplona, Spain
| | - Marina Bárcena-Varela
- Universidad de Navarra, Facultad de Medicina, Departamento de Microbiología y Parasitología, Instituto de Salud Tropical (ISTUN) e Instituto de Investigación Sanitaria de Navarra (IdISNA), Pamplona, Spain
| | - Beatriz Aragón-Aranda
- Universidad de Navarra, Facultad de Medicina, Departamento de Microbiología y Parasitología, Instituto de Salud Tropical (ISTUN) e Instituto de Investigación Sanitaria de Navarra (IdISNA), Pamplona, Spain
| | - Estrella Martínez-Gómez
- Universidad de Navarra, Facultad de Medicina, Departamento de Microbiología y Parasitología, Instituto de Salud Tropical (ISTUN) e Instituto de Investigación Sanitaria de Navarra (IdISNA), Pamplona, Spain
| | - Amaia Zúñiga-Ripa
- Universidad de Navarra, Facultad de Medicina, Departamento de Microbiología y Parasitología, Instituto de Salud Tropical (ISTUN) e Instituto de Investigación Sanitaria de Navarra (IdISNA), Pamplona, Spain
| | - María J de Miguel
- Unidad de Producción y Sanidad Animal, Instituto Agroalimentario de Aragón, Centro de Investigación y Tecnología Agroalimentaria de Aragón - Universidad de Zaragoza, Zaragoza, Spain
| | - Toby Leigh Bartholomew
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom
| | - Sean Hanniffy
- Institut National de la Santé et de la Recherche Médicale, U1104, Centre National de la Recherche Scientifique UMR7280, Centre d'Immunologie de Marseille-Luminy, Aix-Marseille University UM2, Marseille, France
| | - María-Jesús Grilló
- Instituto de Agrobiotecnología, Consejo Superior de Investigaciones Científicas - Universidad Pública de Navarra - Gobierno de Navarra, Pamplona, Spain
| | | | - José A Bengoechea
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom
| | - Vilma Arce-Gorvel
- Institut National de la Santé et de la Recherche Médicale, U1104, Centre National de la Recherche Scientifique UMR7280, Centre d'Immunologie de Marseille-Luminy, Aix-Marseille University UM2, Marseille, France
| | - Jean-Pierre Gorvel
- Institut National de la Santé et de la Recherche Médicale, U1104, Centre National de la Recherche Scientifique UMR7280, Centre d'Immunologie de Marseille-Luminy, Aix-Marseille University UM2, Marseille, France
| | - Ignacio Moriyón
- Universidad de Navarra, Facultad de Medicina, Departamento de Microbiología y Parasitología, Instituto de Salud Tropical (ISTUN) e Instituto de Investigación Sanitaria de Navarra (IdISNA), Pamplona, Spain
| | - Maite Iriarte
- Universidad de Navarra, Facultad de Medicina, Departamento de Microbiología y Parasitología, Instituto de Salud Tropical (ISTUN) e Instituto de Investigación Sanitaria de Navarra (IdISNA), Pamplona, Spain
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8
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Kidd TJ, Mills G, Sá-Pessoa J, Dumigan A, Frank CG, Insua JL, Ingram R, Hobley L, Bengoechea JA. A Klebsiella pneumoniae antibiotic resistance mechanism that subdues host defences and promotes virulence. EMBO Mol Med 2017; 9:430-447. [PMID: 28202493 PMCID: PMC5376759 DOI: 10.15252/emmm.201607336] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Klebsiella pneumoniae is an important cause of multidrug‐resistant infections worldwide. Recent studies highlight the emergence of multidrug‐resistant K. pneumoniae strains which show resistance to colistin, a last‐line antibiotic, arising from mutational inactivation of the mgrB regulatory gene. However, the precise molecular resistance mechanisms of mgrB‐associated colistin resistance and its impact on virulence remain unclear. Here, we constructed an mgrB gene K. pneumoniae mutant and performed characterisation of its lipid A structure, polymyxin and antimicrobial peptide resistance, virulence and inflammatory responses upon infection. Our data reveal that mgrB mutation induces PhoPQ‐governed lipid A remodelling which confers not only resistance to polymyxins, but also enhances K. pneumoniae virulence by decreasing antimicrobial peptide susceptibility and attenuating early host defence response activation. Overall, our findings have important implications for patient management and antimicrobial stewardship, while also stressing antibiotic resistance development is not inexorably linked with subdued bacterial fitness and virulence.
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Affiliation(s)
- Timothy J Kidd
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, UK.,School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, Australia.,Child Health Research Centre, The University of Queensland, Brisbane, Qld, Australia
| | - Grant Mills
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - Joana Sá-Pessoa
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - Amy Dumigan
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - Christian G Frank
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - José L Insua
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - Rebecca Ingram
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - Laura Hobley
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - José A Bengoechea
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, UK
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9
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Lacoma A, Cano V, Moranta D, Regueiro V, Domínguez-Villanueva D, Laabei M, González-Nicolau M, Ausina V, Prat C, Bengoechea JA. Investigating intracellular persistence of Staphylococcus aureus within a murine alveolar macrophage cell line. Virulence 2017; 8:1761-1775. [PMID: 28762868 PMCID: PMC5810471 DOI: 10.1080/21505594.2017.1361089] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Objective: Staphylococcus aureus is a particularly difficult pathogen to eradicate from the respiratory tract. Previous studies have highlighted the intracellular capacity of S.aureus in several phagocytic and non-phagocytic cells. The aim of this study was to define S.aureus interaction within a murine alveolar macrophage cell line. Methods: Cell line MH-S was infected with Newman strain. Molecular mechanisms involved in phagocytosis were explored. To assess whether S.aureus survives intracellularly quantitative (gentamicin protection assays and bacterial plating) and qualitative analysis (immunofluorescence microscopy) were performed. Bacterial colocalization with different markers of the endocytic pathway was examined to characterize its intracellular trafficking. Results: We found that S.aureus uptake requires host actin polymerization, microtubule assembly and activation of phosphatidylinositol 3-kinase signaling. Time course experiments showed that Newman strain was able to persist within macrophages at least until 28.5 h post infection. We observed that intracellular bacteria are located inside an acidic subcellular compartment, which co-localizes with the late endosome/lysosome markers Lamp-1, Rab7 and RILP. Colocalization counts with TMR-dextran might reflect a balance between bacterial killing and intracellular survival. Conclusions: This study indicates that S.aureus persists and replicates inside murine alveolar macrophages, representing a privileged niche that can potentially offer protection from antimicrobial activity and immunological host defense mechanisms.
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Affiliation(s)
- A Lacoma
- a Servei de Microbiologia , Hospital Universitari "Germans Trias i Pujol," Institut en Ciències de la Salut "Germans Trias i Pujol," Universitat Autònoma de Barcelona , Badalona , Spain.,b CIBER Enfermedades Respiratorias (CIBERES) , Instituto de Salud Carlos III , Madrid , Spain
| | - V Cano
- b CIBER Enfermedades Respiratorias (CIBERES) , Instituto de Salud Carlos III , Madrid , Spain.,c Laboratory "Infection and Immunity," Fundación de Investigación Sanitaria de las Islas Baleares (FISIB), Instituto de Investigación Sanitaria de Palma (IdISPa) , Palma , Spain
| | - D Moranta
- b CIBER Enfermedades Respiratorias (CIBERES) , Instituto de Salud Carlos III , Madrid , Spain.,c Laboratory "Infection and Immunity," Fundación de Investigación Sanitaria de las Islas Baleares (FISIB), Instituto de Investigación Sanitaria de Palma (IdISPa) , Palma , Spain
| | - V Regueiro
- b CIBER Enfermedades Respiratorias (CIBERES) , Instituto de Salud Carlos III , Madrid , Spain.,c Laboratory "Infection and Immunity," Fundación de Investigación Sanitaria de las Islas Baleares (FISIB), Instituto de Investigación Sanitaria de Palma (IdISPa) , Palma , Spain
| | - D Domínguez-Villanueva
- a Servei de Microbiologia , Hospital Universitari "Germans Trias i Pujol," Institut en Ciències de la Salut "Germans Trias i Pujol," Universitat Autònoma de Barcelona , Badalona , Spain
| | - M Laabei
- a Servei de Microbiologia , Hospital Universitari "Germans Trias i Pujol," Institut en Ciències de la Salut "Germans Trias i Pujol," Universitat Autònoma de Barcelona , Badalona , Spain
| | - M González-Nicolau
- b CIBER Enfermedades Respiratorias (CIBERES) , Instituto de Salud Carlos III , Madrid , Spain.,c Laboratory "Infection and Immunity," Fundación de Investigación Sanitaria de las Islas Baleares (FISIB), Instituto de Investigación Sanitaria de Palma (IdISPa) , Palma , Spain
| | - V Ausina
- a Servei de Microbiologia , Hospital Universitari "Germans Trias i Pujol," Institut en Ciències de la Salut "Germans Trias i Pujol," Universitat Autònoma de Barcelona , Badalona , Spain.,b CIBER Enfermedades Respiratorias (CIBERES) , Instituto de Salud Carlos III , Madrid , Spain
| | - C Prat
- a Servei de Microbiologia , Hospital Universitari "Germans Trias i Pujol," Institut en Ciències de la Salut "Germans Trias i Pujol," Universitat Autònoma de Barcelona , Badalona , Spain.,b CIBER Enfermedades Respiratorias (CIBERES) , Instituto de Salud Carlos III , Madrid , Spain
| | - J A Bengoechea
- b CIBER Enfermedades Respiratorias (CIBERES) , Instituto de Salud Carlos III , Madrid , Spain.,c Laboratory "Infection and Immunity," Fundación de Investigación Sanitaria de las Islas Baleares (FISIB), Instituto de Investigación Sanitaria de Palma (IdISPa) , Palma , Spain.,d Consejo Superior de Investigaciones Científicas , Madrid , Spain.,e Centre for Experimental Medicine , Queen's University Belfast , UK
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10
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Martínez I, Oliveros JC, Cuesta I, de la Barrera J, Ausina V, Casals C, de Lorenzo A, García E, García-Fojeda B, Garmendia J, González-Nicolau M, Lacoma A, Menéndez M, Moranta D, Nieto A, Ortín J, Pérez-González A, Prat C, Ramos-Sevillano E, Regueiro V, Rodriguez-Frandsen A, Solís D, Yuste J, Bengoechea JA, Melero JA. Apoptosis, Toll-like, RIG-I-like and NOD-like Receptors Are Pathways Jointly Induced by Diverse Respiratory Bacterial and Viral Pathogens. Front Microbiol 2017; 8:276. [PMID: 28298903 PMCID: PMC5331050 DOI: 10.3389/fmicb.2017.00276] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 02/09/2017] [Indexed: 12/18/2022] Open
Abstract
Lower respiratory tract infections are among the top five leading causes of human death. Fighting these infections is therefore a world health priority. Searching for induced alterations in host gene expression shared by several relevant respiratory pathogens represents an alternative to identify new targets for wide-range host-oriented therapeutics. With this aim, alveolar macrophages were independently infected with three unrelated bacterial (Streptococcus pneumoniae, Klebsiella pneumoniae, and Staphylococcus aureus) and two dissimilar viral (respiratory syncytial virus and influenza A virus) respiratory pathogens, all of them highly relevant for human health. Cells were also activated with bacterial lipopolysaccharide (LPS) as a prototypical pathogen-associated molecular pattern. Patterns of differentially expressed cellular genes shared by the indicated pathogens were searched by microarray analysis. Most of the commonly up-regulated host genes were related to the innate immune response and/or apoptosis, with Toll-like, RIG-I-like and NOD-like receptors among the top 10 signaling pathways with over-expressed genes. These results identify new potential broad-spectrum targets to fight the important human infections caused by the bacteria and viruses studied here.
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Affiliation(s)
- Isidoro Martínez
- Centro Nacional de Microbiología, Instituto de Salud Carlos IIIMadrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos IIIMadrid, Spain
| | | | - Isabel Cuesta
- Centro Nacional de Microbiología, Instituto de Salud Carlos III Madrid, Spain
| | - Jorge de la Barrera
- Centro Nacional de Microbiología, Instituto de Salud Carlos III Madrid, Spain
| | - Vicente Ausina
- Servei de Microbiologia, Hospital Universitari Germans Trias i Pujol, Badalona, Institut d' Investigació Germans Trias i Pujol, Universitat Autònoma de BarcelonaBarcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos IIIMadrid, Spain
| | - Cristina Casals
- Departmento de Bioquímica y Biología Molecular I, Universidad ComplutenseMadrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos IIIMadrid, Spain
| | - Alba de Lorenzo
- Departmento de Bioquímica y Biología Molecular I, Universidad ComplutenseMadrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos IIIMadrid, Spain
| | - Ernesto García
- Centro de Investigaciones Biológicas (CSIC)Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos IIIMadrid, Spain
| | - Belén García-Fojeda
- Departmento de Bioquímica y Biología Molecular I, Universidad ComplutenseMadrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos IIIMadrid, Spain
| | - Junkal Garmendia
- Instituto de Agrobiotecnología, CSIC-Universidad Pública de Navarra-GobNavarra, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos IIIMadrid, Spain
| | - Mar González-Nicolau
- Fundación de Investigación Sanitaria de las Islas Baleares, Instituto de Investigación Sanitaria de PalmaPalma, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos IIIMadrid, Spain
| | - Alicia Lacoma
- Servei de Microbiologia, Hospital Universitari Germans Trias i Pujol, Badalona, Institut d' Investigació Germans Trias i Pujol, Universitat Autònoma de BarcelonaBarcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos IIIMadrid, Spain
| | - Margarita Menéndez
- Instituto de Química Física Rocasolano (CSIC)Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos IIIMadrid, Spain
| | - David Moranta
- Fundación de Investigación Sanitaria de las Islas Baleares, Instituto de Investigación Sanitaria de PalmaPalma, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos IIIMadrid, Spain
| | - Amelia Nieto
- Centro Nacional de Biotecnología (CSIC)Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos IIIMadrid, Spain
| | - Juan Ortín
- Centro Nacional de Biotecnología (CSIC)Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos IIIMadrid, Spain
| | - Alicia Pérez-González
- Centro Nacional de Biotecnología (CSIC)Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos IIIMadrid, Spain
| | - Cristina Prat
- Servei de Microbiologia, Hospital Universitari Germans Trias i Pujol, Badalona, Institut d' Investigació Germans Trias i Pujol, Universitat Autònoma de BarcelonaBarcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos IIIMadrid, Spain
| | - Elisa Ramos-Sevillano
- Centro de Investigaciones Biológicas (CSIC)Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos IIIMadrid, Spain
| | - Verónica Regueiro
- Fundación de Investigación Sanitaria de las Islas Baleares, Instituto de Investigación Sanitaria de PalmaPalma, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos IIIMadrid, Spain
| | - Ariel Rodriguez-Frandsen
- Centro Nacional de Biotecnología (CSIC)Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos IIIMadrid, Spain
| | - Dolores Solís
- Instituto de Química Física Rocasolano (CSIC)Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos IIIMadrid, Spain
| | - José Yuste
- Centro de Investigaciones Biológicas (CSIC)Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos IIIMadrid, Spain
| | - José A Bengoechea
- Fundación de Investigación Sanitaria de las Islas Baleares, Instituto de Investigación Sanitaria de PalmaPalma, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos IIIMadrid, Spain
| | - José A Melero
- Centro Nacional de Microbiología, Instituto de Salud Carlos IIIMadrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos IIIMadrid, Spain
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11
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Leskinen K, Pajunen MI, Varjosalo M, Fernández-Carrasco H, Bengoechea JA, Skurnik M. Several Hfq-dependent alterations in physiology of Yersinia enterocolitica O:3 are mediated by derepression of the transcriptional regulator RovM. Mol Microbiol 2017; 103:1065-1091. [PMID: 28010054 DOI: 10.1111/mmi.13610] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/17/2016] [Indexed: 12/27/2022]
Abstract
In bacteria, the RNA chaperone Hfq enables pairing of small regulatory RNAs with their target mRNAs and therefore is a key player of post-transcriptional regulation network. As a global regulator, Hfq is engaged in the adaptation to external environment, regulation of metabolism and bacterial virulence. In this study we used RNA-sequencing and quantitative proteomics (LC-MS/MS) to elucidate the role of this chaperone in the physiology and virulence of Yersinia enterocolitica serotype O:3. This global approach revealed the profound impact of Hfq on gene and protein expression. Furthermore, the role of Hfq in the cell morphology, metabolism, cell wall integrity, resistance to external stresses and pathogenicity was evaluated. Importantly, our results revealed that several alterations typical for the hfq-negative phenotype were due to derepression of the transcriptional factor RovM. The overexpression of RovM caused by the loss of Hfq chaperone resulted in extended growth defect, alterations in the lipid A structure, motility and biofilm formation defects, as well as changes in mannitol utilization. Furthermore, in Y. enterocolitica RovM only in the presence of Hfq affected the abundance of RpoS. Finally, the impact of hfq and rovM mutations on the virulence was assessed in the mouse infection model.
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Affiliation(s)
- Katarzyna Leskinen
- Department of Bacteriology and Immunology, Medicum, Research Programs Unit, Immunobiology, University of Helsinki, Finland
| | - Maria I Pajunen
- Department of Bacteriology and Immunology, Medicum, Research Programs Unit, Immunobiology, University of Helsinki, Finland
| | - Markku Varjosalo
- Institute of Biotechnology, University of Helsinki.,Biocentrum Helsinki, Finland: Finnish Institute of Molecular Medicine, Finland
| | | | - José A Bengoechea
- Centre for Experimental Medicine, Queens University Belfast, Belfast, UK
| | - Mikael Skurnik
- Department of Bacteriology and Immunology, Medicum, Research Programs Unit, Immunobiology, University of Helsinki, Finland.,Division of Clinical Microbiology, Helsinki University Hospital, HUSLAB, Helsinki, Finland
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12
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Affiliation(s)
- José A Bengoechea
- a Center for Experimental Medicine, Queen's University Belfast , Belfast , Northern Ireland , UK
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13
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Cano V, March C, Insua JL, Aguiló N, Llobet E, Moranta D, Regueiro V, Brennan GP, Millán-Lou MI, Martín C, Garmendia J, Bengoechea JA. Klebsiella pneumoniaesurvives within macrophages by avoiding delivery to lysosomes. Cell Microbiol 2015; 17:1537-60. [DOI: 10.1111/cmi.12466] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 05/22/2015] [Accepted: 05/28/2015] [Indexed: 12/22/2022]
Affiliation(s)
- Victoria Cano
- Laboratory Infection and Immunity; Fundació d'Investigació Sanitària de les Illes Balears (FISIB); Bunyola Spain
- Centro de Investigación Biomédica en Red Enfermedades Respiratorias (CIBERES); Bunyola Spain
| | - Catalina March
- Laboratory Infection and Immunity; Fundació d'Investigació Sanitària de les Illes Balears (FISIB); Bunyola Spain
- Centro de Investigación Biomédica en Red Enfermedades Respiratorias (CIBERES); Bunyola Spain
| | - Jose Luis Insua
- Centre for Infection and Immunity; Queen's University Belfast; Belfast UK
| | - Nacho Aguiló
- Centro de Investigación Biomédica en Red Enfermedades Respiratorias (CIBERES); Bunyola Spain
- Grupo de Genética de Micobacterias, Dpto. Microbiología, Medicina Preventiva y Salud Pública; Universidad de Zaragoza; Zaragoza Spain
| | - Enrique Llobet
- Laboratory Infection and Immunity; Fundació d'Investigació Sanitària de les Illes Balears (FISIB); Bunyola Spain
- Centro de Investigación Biomédica en Red Enfermedades Respiratorias (CIBERES); Bunyola Spain
- Institut d'Investigació Sanitària de Palma (IdISPa); Palma Spain
| | - David Moranta
- Laboratory Infection and Immunity; Fundació d'Investigació Sanitària de les Illes Balears (FISIB); Bunyola Spain
- Centro de Investigación Biomédica en Red Enfermedades Respiratorias (CIBERES); Bunyola Spain
- Institut d'Investigació Sanitària de Palma (IdISPa); Palma Spain
| | - Verónica Regueiro
- Laboratory Infection and Immunity; Fundació d'Investigació Sanitària de les Illes Balears (FISIB); Bunyola Spain
- Centro de Investigación Biomédica en Red Enfermedades Respiratorias (CIBERES); Bunyola Spain
- Institut d'Investigació Sanitària de Palma (IdISPa); Palma Spain
| | - Gerard P. Brennan
- School of Biological Sciences; Queen's University Belfast; Belfast UK
| | - Maria Isabel Millán-Lou
- Centro de Investigación Biomédica en Red Enfermedades Respiratorias (CIBERES); Bunyola Spain
- Grupo de Genética de Micobacterias, Dpto. Microbiología, Medicina Preventiva y Salud Pública; Universidad de Zaragoza; Zaragoza Spain
| | - Carlos Martín
- Centro de Investigación Biomédica en Red Enfermedades Respiratorias (CIBERES); Bunyola Spain
- Grupo de Genética de Micobacterias, Dpto. Microbiología, Medicina Preventiva y Salud Pública; Universidad de Zaragoza; Zaragoza Spain
| | - Junkal Garmendia
- Centro de Investigación Biomédica en Red Enfermedades Respiratorias (CIBERES); Bunyola Spain
- Instituto de Agrobiotecnología; CSIC - Universidad Pública de Navarra-Gobierno de Navarra; Mutilva Spain
| | - José A. Bengoechea
- Centre for Infection and Immunity; Queen's University Belfast; Belfast UK
- Consejo Superior de Investigaciones Científicas (CSIC); Madrid Spain
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14
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Tomás A, Lery L, Regueiro V, Pérez-Gutiérrez C, Martínez V, Moranta D, Llobet E, González-Nicolau M, Insua JL, Tomas JM, Sansonetti PJ, Tournebize R, Bengoechea JA. Functional Genomic Screen Identifies Klebsiella pneumoniae Factors Implicated in Blocking Nuclear Factor κB (NF-κB) Signaling. J Biol Chem 2015; 290:16678-97. [PMID: 25971969 PMCID: PMC4505419 DOI: 10.1074/jbc.m114.621292] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Indexed: 01/01/2023] Open
Abstract
Klebsiella pneumoniae is an etiologic agent of community-acquired and nosocomial pneumonia. It has been shown that K. pneumoniae infections are characterized by reduced early inflammatory response. Recently our group has shown that K. pneumoniae dampens the activation of inflammatory responses by antagonizing the activation of the NF-κB canonical pathway. Our results revealed that K. pneumoniae capsule polysaccharide (CPS) was necessary but not sufficient to attenuate inflammation. To identify additional Klebsiella factors required to dampen inflammation, we standardized and applied a high-throughput gain-of-function screen to examine a Klebsiella transposon mutant library. We identified 114 mutants that triggered the activation of NF-κB. Two gene ontology categories accounted for half of the loci identified in the screening: metabolism and transport genes (32% of the mutants) and envelope-related genes (17%). Characterization of the mutants revealed that the lack of the enterobactin siderophore was linked to a reduced CPS expression, which in turn underlined the NF-κB activation induced by the mutant. The lipopolysaccharide (LPS) O-polysaccharide and the pullulanase (PulA) type 2 secretion system (T2SS) are required for full effectiveness of the immune evasion. Importantly, these factors do not play a redundant role. The fact that LPS O-polysaccharide and T2SS mutant-induced responses were dependent on TLR2-TLR4-MyD88 activation suggested that LPS O-polysaccharide and PulA perturbed Toll-like receptor (TLR)-dependent recognition of K. pneumoniae. Finally, we demonstrate that LPS O-polysaccharide and pulA mutants are attenuated in the pneumonia mouse model. We propose that LPS O-polysaccharide and PulA T2SS could be new targets for the design of new antimicrobials. Increasing TLR-governed defense responses might provide also selective alternatives for the management of K. pneumoniae pneumonia.
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Affiliation(s)
- Anna Tomás
- From the Infection and Immunity Program, Fundación de Investigación Sanitaria de las Islas Baleares (FISIB), 07110 Mallorca, Spain, the Instituto de Investigación Sanitaria de Palma (IdisPa), 07120 Mallorca, Spain, the Centro de Investigación Biomédica en Red Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain
| | - Leticia Lery
- the Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, 75724 Paris, France, INSERM U786, 75724 Paris, France
| | - Verónica Regueiro
- From the Infection and Immunity Program, Fundación de Investigación Sanitaria de las Islas Baleares (FISIB), 07110 Mallorca, Spain, the Instituto de Investigación Sanitaria de Palma (IdisPa), 07120 Mallorca, Spain, the Centro de Investigación Biomédica en Red Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain
| | - Camino Pérez-Gutiérrez
- From the Infection and Immunity Program, Fundación de Investigación Sanitaria de las Islas Baleares (FISIB), 07110 Mallorca, Spain, the Instituto de Investigación Sanitaria de Palma (IdisPa), 07120 Mallorca, Spain, the Centro de Investigación Biomédica en Red Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain
| | - Verónica Martínez
- From the Infection and Immunity Program, Fundación de Investigación Sanitaria de las Islas Baleares (FISIB), 07110 Mallorca, Spain, the Instituto de Investigación Sanitaria de Palma (IdisPa), 07120 Mallorca, Spain, the Centro de Investigación Biomédica en Red Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain
| | - David Moranta
- From the Infection and Immunity Program, Fundación de Investigación Sanitaria de las Islas Baleares (FISIB), 07110 Mallorca, Spain, the Instituto de Investigación Sanitaria de Palma (IdisPa), 07120 Mallorca, Spain, the Centro de Investigación Biomédica en Red Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain
| | - Enrique Llobet
- From the Infection and Immunity Program, Fundación de Investigación Sanitaria de las Islas Baleares (FISIB), 07110 Mallorca, Spain, the Instituto de Investigación Sanitaria de Palma (IdisPa), 07120 Mallorca, Spain, the Centro de Investigación Biomédica en Red Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain
| | - Mar González-Nicolau
- From the Infection and Immunity Program, Fundación de Investigación Sanitaria de las Islas Baleares (FISIB), 07110 Mallorca, Spain, the Instituto de Investigación Sanitaria de Palma (IdisPa), 07120 Mallorca, Spain, the Centro de Investigación Biomédica en Red Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain
| | - Jose L Insua
- the Centre for Infection and Immunity, Queen's University Belfast, Belfast BT9 7AE, United Kingdom
| | - Juan M Tomas
- the Departamento de Microbiología, Facultad de Biología, Universidad de Barcelona, 08028 Barcelona, Spain
| | - Philippe J Sansonetti
- the Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, 75724 Paris, France, INSERM U786, 75724 Paris, France, Chaire de Microbiologie et Maladies Infectieuses, Collège de France, 75231 Paris, France
| | - Régis Tournebize
- the Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, 75724 Paris, France, INSERM U786, 75724 Paris, France, Imagopole, Plateforme d'Imagerie Dynamique, Institut Pasteur, 75724 Paris, France, and
| | - José A Bengoechea
- the Centre for Infection and Immunity, Queen's University Belfast, Belfast BT9 7AE, United Kingdom, the Consejo Superior de Investigaciones Científicas (CSIC), 28008 Madrid, Spain
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15
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Pérez-Cidoncha M, Killip MJ, Asensio VJ, Fernández Y, Bengoechea JA, Randall RE, Ortín J. Generation of replication-proficient influenza virus NS1 point mutants with interferon-hyperinducer phenotype. PLoS One 2014; 9:e98668. [PMID: 24887174 PMCID: PMC4041880 DOI: 10.1371/journal.pone.0098668] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 05/05/2014] [Indexed: 12/24/2022] Open
Abstract
The NS1 protein of influenza A viruses is the dedicated viral interferon (IFN)-antagonist. Viruses lacking NS1 protein expression cannot multiply in normal cells but are viable in cells deficient in their ability to produce or respond to IFN. Here we report an unbiased mutagenesis approach to identify positions in the influenza A NS1 protein that modulate the IFN response upon infection. A random library of virus ribonucleoproteins containing circa 40 000 point mutants in NS1 were transferred to infectious virus and amplified in MDCK cells unable to respond to interferon. Viruses that activated the interferon (IFN) response were subsequently selected by their ability to induce expression of green-fluorescent protein (GFP) following infection of A549 cells bearing an IFN promoter-dependent GFP gene. Using this approach we isolated individual mutant viruses that replicate to high titers in IFN-compromised cells but, compared to wild type viruses, induced higher levels of IFN in IFN-competent cells and had a reduced capacity to counteract exogenous IFN. Most of these viruses contained not previously reported NS1 mutations within either the RNA-binding domain, the effector domain or the linker region between them. These results indicate that subtle alterations in NS1 can reduce its effectiveness as an IFN antagonist without affecting the intrinsic capacity of the virus to multiply. The general approach reported here may facilitate the generation of replication-proficient, IFN-inducing virus mutants, that potentially could be developed as attenuated vaccines against a variety of viruses.
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Affiliation(s)
- Maite Pérez-Cidoncha
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología (CSIC), Madrid, Spain
- Ciber de Enfermedades Respiratorias (ISCIII), Madrid, Spain
| | - Marian J. Killip
- School of Biology, Centre for Biomolecular Sciences, University of St Andrews, St Andrews, United Kingdom
| | - Víctor J. Asensio
- Fundació d'Investigació Sanitària de les Illes Balears (FISIB), Bunyola, Mallorca, Spain
| | - Yolanda Fernández
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología (CSIC), Madrid, Spain
- Ciber de Enfermedades Respiratorias (ISCIII), Madrid, Spain
| | - José A. Bengoechea
- Laboratory Microbial Pathogenesis, Fundació d'Investigació Sanitària de les Illes Balears (FISIB), Bunyola, Mallorca, Spain
- Ciber de Enfermedades Respiratorias (ISCIII), Madrid, Spain
| | - Richard E. Randall
- School of Biology, Centre for Biomolecular Sciences, University of St Andrews, St Andrews, United Kingdom
| | - Juan Ortín
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología (CSIC), Madrid, Spain
- Ciber de Enfermedades Respiratorias (ISCIII), Madrid, Spain
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Lery LMS, Frangeul L, Tomas A, Passet V, Almeida AS, Bialek-Davenet S, Barbe V, Bengoechea JA, Sansonetti P, Brisse S, Tournebize R. Comparative analysis of Klebsiella pneumoniae genomes identifies a phospholipase D family protein as a novel virulence factor. BMC Biol 2014; 12:41. [PMID: 24885329 PMCID: PMC4068068 DOI: 10.1186/1741-7007-12-41] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 05/15/2014] [Indexed: 12/17/2022] Open
Abstract
Background Klebsiella pneumoniae strains are pathogenic to animals and humans, in which they are both a frequent cause of nosocomial infections and a re-emerging cause of severe community-acquired infections. K. pneumoniae isolates of the capsular serotype K2 are among the most virulent. In order to identify novel putative virulence factors that may account for the severity of K2 infections, the genome sequence of the K2 reference strain Kp52.145 was determined and compared to two K1 and K2 strains of low virulence and to the reference strains MGH 78578 and NTUH-K2044. Results In addition to diverse functions related to host colonization and virulence encoded in genomic regions common to the four strains, four genomic islands specific for Kp52.145 were identified. These regions encoded genes for the synthesis of colibactin toxin, a putative cytotoxin outer membrane protein, secretion systems, nucleases and eukaryotic-like proteins. In addition, an insertion within a type VI secretion system locus included sel1 domain containing proteins and a phospholipase D family protein (PLD1). The pld1 mutant was avirulent in a pneumonia model in mouse. The pld1 mRNA was expressed in vivo and the pld1 gene was associated with K. pneumoniae isolates from severe infections. Analysis of lipid composition of a defective E. coli strain complemented with pld1 suggests an involvement of PLD1 in cardiolipin metabolism. Conclusions Determination of the complete genome of the K2 reference strain identified several genomic islands comprising putative elements of pathogenicity. The role of PLD1 in pathogenesis was demonstrated for the first time and suggests that lipid metabolism is a novel virulence mechanism of K. pneumoniae.
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Affiliation(s)
- Letícia M S Lery
- Institut Pasteur - Pathogénie Microbienne Moléculaire, Paris, France.
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Garmendia J, Martí-Lliteras P, Moleres J, Puig C, Bengoechea JA. Genotypic and phenotypic diversity of the noncapsulated Haemophilus influenzae: adaptation and pathogenesis in the human airways. Int Microbiol 2013; 15:159-72. [PMID: 23844475 DOI: 10.2436/20.1501.01.169] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The human respiratory tract contains a highly adapted microbiota including commensal and opportunistic pathogens. Noncapsulated or nontypable Haemophilus influenzae (NTHi) is a human-restricted member of the normal airway microbiota in healthy carriers and an opportunistic pathogen in immunocompromised individuals. The duality of NTHi as a colonizer and as a symptomatic infectious agent is closely related to its adaptation to the host, which in turn greatly relies on the genetic plasticity of the bacterium and is facilitated by its condition as a natural competent. The variable genotype of NTHi accounts for its heterogeneous gene expression and variable phenotype, leading to differential host-pathogen interplay among isolates. Here we review our current knowledge of NTHi diversity in terms of genotype, gene expression, antigenic variation, and the phenotypes associated with colonization and pathogenesis. The potential benefits of NTHi diversity studies discussed herein include the unraveling of pathogenicity clues, the generation of tools to predict virulence from genomic data, and the exploitation of a unique natural system for the continuous monitoring of long-term bacterial evolution in human airways exposed to noxious agents. Finally, we highlight the challenge of monitoring both the pathogen and the host in longitudinal studies, and of applying comparative genomics to clarify the meaning of the vast NTHi genetic diversity and its translation to virulence phenotypes.
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Affiliation(s)
- Junkal Garmendia
- Institute for Agrobiotechnology, CSIC-Public University of Navarra-Government of Navarra, Mutilva, Spain.
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Frank CG, Reguerio V, Rother M, Moranta D, Maeurer AP, Garmendia J, Meyer TF, Bengoechea JA. Klebsiella pneumoniae targets an EGF receptor-dependent pathway to subvert inflammation. Cell Microbiol 2013; 15:1212-33. [PMID: 23347154 DOI: 10.1111/cmi.12110] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 12/21/2012] [Accepted: 01/12/2013] [Indexed: 12/24/2022]
Abstract
The NF-κB transcriptional factor plays a key role governing the activation of immune responses. Klebsiella pneumoniae is an important cause of community-acquired and nosocomial pneumonia. Evidence indicates that K. pneumoniae infections are characterized by lacking an early inflammatory response. Recently, we have demonstrated that Klebsiella antagonizes the activation of NF-κB via the deubiquitinase CYLD. In this work, by applying a high-throughput siRNA gain-of-function screen interrogating the human kinome, we identified 17 kinases that when targeted by siRNA restored IL-1β-dependent NF-κB translocation in infected cells. Further characterization revealed that K. pneumoniae activates an EGF receptor (EGFR)-phosphatidylinositol 3-OH kinase (PI3K)-AKT-PAK4-ERK-GSK3β signalling pathway to attenuate the cytokine-dependent nuclear translocation of NF-κB. Our data also revealed that CYLD is a downstream effector of K. pneumoniae-induced EGFR-PI3K-AKT-PAK4-ERK-GSK3β signalling pathway. Our efforts to identify the bacterial factor(s)responsible for EGFR activation demonstrate that a capsule (CPS) mutant did not activate EGFR hence suggesting that CPS could mediate the activation of EGFR. Supporting this notion, purified CPS did activate EGFR as well as the EGFR-dependent PI3K-AKT-PAK4-ERK-GSK3β signalling pathway. CPS-mediated EGFR activation was dependent on a TLR4-MyD88-c-SRC-dependent pathway. Several promising drugs have been developed to antagonize this cascade. We propose that agents targeting this signalling pathway might provide selective alternatives for the management of K. pneumoniae pneumonias.
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Affiliation(s)
- Christian G Frank
- Laboratory Microbial Pathogenesis, Fundació d'Investigació Sanitària de les Illes Balears (FISIB), Recinto Hospital Joan March, 07110, Bunyola, Spain
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Abstract
This short review establishes the conceptual bases and discusses the principal aspects of P4-shorthand for predictive, preventive, personalized and participatory medicine-medicine, in the framework of infectious diseases. P4 medicine is a new way to approach medical care; instead of acting when the patient is sick, physicians will be able to detect early warnings of disease to take early action. Furthermore, people might even be able to adjust their lifestyles to prevent disease. P4 medicine is fuelled by systems approaches to disease, including methods for personalized genome sequencing and new computational techniques for building dynamic disease predictive networks from massive amounts of data from a variety of OMICs. An excellent example of the effectiveness of the P4 medicine approach is the change in cancer treatments. Emphasis is placed on early detection, followed by genotyping of the patient to use the most adequate treatment according to the genetic background. Cardiovascular diseases and perhaps even neurodegenerative disorders will be the next targets for P4 medicine. The application of P4 medicine to infectious diseases is still in its infancy, but is a promising field that will provide much benefit to both the patients and the health-care system.
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Affiliation(s)
- José A Bengoechea
- Laboratory of Microbial Pathogenesis, Foundation Health Balearic Islands, Spanish National Research Council, Network Biomedical Research Center in Lung Diseases (CIBERES), Mallorca, Spain.
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20
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Reinés M, Llobet E, Dahlström KM, Pérez-Gutiérrez C, Llompart CM, Torrecabota N, Salminen TA, Bengoechea JA. Deciphering the acylation pattern of Yersinia enterocolitica lipid A. PLoS Pathog 2012; 8:e1002978. [PMID: 23133372 PMCID: PMC3486919 DOI: 10.1371/journal.ppat.1002978] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 09/05/2012] [Indexed: 12/20/2022] Open
Abstract
Pathogenic bacteria may modify their surface to evade the host innate immune response. Yersinia enterocolitica modulates its lipopolysaccharide (LPS) lipid A structure, and the key regulatory signal is temperature. At 21°C, lipid A is hexa-acylated and may be modified with aminoarabinose or palmitate. At 37°C, Y. enterocolitica expresses a tetra-acylated lipid A consistent with the 3′-O-deacylation of the molecule. In this work, by combining genetic and mass spectrometric analysis, we establish that Y. enterocolitica encodes a lipid A deacylase, LpxR, responsible for the lipid A structure observed at 37°C. Western blot analyses indicate that LpxR exhibits latency at 21°C, deacylation of lipid A is not observed despite the expression of LpxR in the membrane. Aminoarabinose-modified lipid A is involved in the latency. 3-D modelling, docking and site-directed mutagenesis experiments showed that LpxR D31 reduces the active site cavity volume so that aminoarabinose containing Kdo2-lipid A cannot be accommodated and, therefore, not deacylated. Our data revealed that the expression of lpxR is negatively controlled by RovA and PhoPQ which are necessary for the lipid A modification with aminoarabinose. Next, we investigated the role of lipid A structural plasticity conferred by LpxR on the expression/function of Y. enterocolitica virulence factors. We present evidence that motility and invasion of eukaryotic cells were reduced in the lpxR mutant grown at 21°C. Mechanistically, our data revealed that the expressions of flhDC and rovA, regulators controlling the flagellar regulon and invasin respectively, were down-regulated in the mutant. In contrast, the levels of the virulence plasmid (pYV)-encoded virulence factors Yops and YadA were not affected in the lpxR mutant. Finally, we establish that the low inflammatory response associated to Y. enterocolitica infections is the sum of the anti-inflammatory action exerted by pYV-encoded YopP and the reduced activation of the LPS receptor by a LpxR-dependent deacylated LPS. Lipopolysaccharide (LPS) is one of the major surface components of Gram-negative bacteria. The LPS contains a molecular pattern recognized by the innate immune system. Not surprisingly, the modification of the LPS pattern is a virulence strategy of several pathogens to evade the innate immune system. Yersinia enterocolitica causes food-borne infections in animals and humans (yersiniosis). Temperature regulates most, if not all, virulence factors of yersiniae including the structure of the LPS lipid A. At 21°C, lipid A is mainly hexa-acylated and may be modified with aminoarabinose or palmitate. In contrast, at 37°C, Y. enterocolitica expresses a unique tetra-acylated lipid A. In this work, we establish that Y. enterocolitica encodes a lipid A deacylase, LpxR, responsible for the lipid A structure expressed by the pathogen at 37°C, the host temperature. Our findings also revealed that the low inflammatory response associated to Y. enterocolitica infections is the sum of the anti-inflammatory action exerted by a Yersinia protein translocated into the cytosol of macrophages and the reduced activation of the LPS receptor complex due to the expression of a LpxR-dependent deacylated LPS.
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Affiliation(s)
- Mar Reinés
- Laboratory Microbial Pathogenesis, Fundació d'Investigació Sanitària de les Illes Balears (FISIB), Recinto Hospital Joan March, Bunyola, Spain
- Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Enrique Llobet
- Laboratory Microbial Pathogenesis, Fundació d'Investigació Sanitària de les Illes Balears (FISIB), Recinto Hospital Joan March, Bunyola, Spain
| | - Käthe M. Dahlström
- Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, Turku, Finland
| | - Camino Pérez-Gutiérrez
- Laboratory Microbial Pathogenesis, Fundació d'Investigació Sanitària de les Illes Balears (FISIB), Recinto Hospital Joan March, Bunyola, Spain
| | - Catalina M. Llompart
- Laboratory Microbial Pathogenesis, Fundació d'Investigació Sanitària de les Illes Balears (FISIB), Recinto Hospital Joan March, Bunyola, Spain
| | - Nuria Torrecabota
- Laboratory Microbial Pathogenesis, Fundació d'Investigació Sanitària de les Illes Balears (FISIB), Recinto Hospital Joan March, Bunyola, Spain
| | - Tiina A. Salminen
- Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, Turku, Finland
| | - José A. Bengoechea
- Laboratory Microbial Pathogenesis, Fundació d'Investigació Sanitària de les Illes Balears (FISIB), Recinto Hospital Joan March, Bunyola, Spain
- Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- * E-mail:
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Llompart-Pou JA, Pérez-Bárcena J, Marsé P, Pérez G, Bengoechea JA, Raurich JM. [Correlation between TLR2 and TLR4 levels and adrenal gland response in trauma patients]. Med Intensiva 2012; 36:590-2. [PMID: 22436317 DOI: 10.1016/j.medin.2012.01.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 01/26/2012] [Accepted: 01/26/2012] [Indexed: 10/28/2022]
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Abstract
The human respiratory tract of individuals with normal lung function maintains a fine-tuned balance, being asymptomatically colonised by the normal microbiota in the upper airways and sterile in the lower tract. This equilibrium may be disrupted by the exposure to insults such as cigarette smoke. In the respiratory tract, the complex and noxious nature of inhaled cigarette smoke alters host-microorganism interaction dynamics at all anatomical levels, causing infections in many cases. Moreover, continuous exposure to cigarette smoke itself causes deleterious effects on the host that can trigger the development of chronic respiratory diseases, such as chronic obstructive pulmonary disease (COPD) and lung cancer. COPD is an irreversible airflow obstruction associated with emphysema, fibrosis, mucus hypersecretion and persistent colonisation of the lower airways by opportunistic pathogens. COPD patients keep a stable (without exacerbation) but progressively worsening condition and suffer periodic exacerbations caused, in most cases, by infections. Although smoking and smoking-associated diseases are associated with a high risk of infection, most therapies aim to reduce inflammatory parameters, but do not necessarily take into account the presence of persistent colonisers. The effect of cigarette smoke on host-pathogen interaction dynamics in the respiratory tract, together with current and novel therapies, is discussed.
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Affiliation(s)
- J Garmendia
- Instituto de Agrobiotecnología, CSIC-Universidad Pública de Navarra-Gobierno de Navarra, 31192 Mutilva, Navarra, Spain.
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López-Rojas R, Docobo-Pérez F, Pachón-Ibáñez ME, de la Torre BG, Fernández-Reyes M, March C, Bengoechea JA, Andreu D, Rivas L, Pachón J. Efficacy of cecropin A-melittin peptides on a sepsis model of infection by pan-resistant Acinetobacter baumannii. Eur J Clin Microbiol Infect Dis 2011; 30:1391-8. [PMID: 21479973 DOI: 10.1007/s10096-011-1233-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 03/19/2011] [Indexed: 02/02/2023]
Abstract
Pan-resistant Acinetobacter baumannii have prompted the search for therapeutic alternatives. We evaluate the efficacy of four cecropin A-melittin hybrid peptides (CA-M) in vivo. Toxicity was determined in mouse erythrocytes and in mice (lethal dose parameters were LD(0), LD(50), LD(100)). Protective dose 50 (PD(50)) was determined by inoculating groups of ten mice with the minimal lethal dose of A. baumannii (BMLD) and treating with doses of each CA-M from 0.5 mg/kg to LD(0). The activity of CA-Ms against A. baumannii was assessed in a peritoneal sepsis model. Mice were sacrificed at 0 and 1, 3, 5, and 7-h post-treatment. Spleen and peritoneal fluid bacterial concentrations were measured. CA(1-8)M(1-18) was the less haemolytic on mouse erythrocytes. LD(0) (mg/kg) was 32 for CA(1-8)M(1-18), CA(1-7)M(2-9), and Oct-CA(1-7)M(2-9), and 16 for CA(1-7)M(5-9). PD(50) was not achieved with non-toxic doses (≤ LD(0)). In the sepsis model, all CA-Ms were bacteriostatic in spleen, and decreased bacterial concentration (p < 0.05) in peritoneal fluid, at 1-h post-treatment; at later times, bacterial regrowth was observed in peritoneal fluid. CA-Ms showed local short-term efficacy in the peritoneal sepsis model caused by pan-resistant Acinetobacter baumannii.
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Affiliation(s)
- R López-Rojas
- Unidad Clínica de Enfermedades Infecciosas, Instituto de Biomedicina de Sevilla, IBIS/Hospital Universitario Virgen del Rocío/Universidad de Sevilla/CSIC Sevilla, 41013 Sevilla, Spain.
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25
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March C, Moranta D, Regueiro V, Llobet E, Tomás A, Garmendia J, Bengoechea JA. Klebsiella pneumoniae outer membrane protein A is required to prevent the activation of airway epithelial cells. J Biol Chem 2011; 286:9956-67. [PMID: 21278256 DOI: 10.1074/jbc.m110.181008] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Outer membrane protein A (OmpA) is a class of proteins highly conserved among the Enterobacteriaceae family and throughout evolution. Klebsiella pneumoniae is a capsulated gram-negative pathogen. It is an important cause of community-acquired and nosocomial pneumonia. Evidence indicates that K. pneumoniae infections are characterized by a lack of an early inflammatory response. Data from our laboratory indicate that K. pneumoniae CPS helps to suppress the host inflammatory response. However, it is unknown whether K. pneumoniae employs additional factors to modulate host inflammatory responses. Here, we report that K. pneumoniae OmpA is important for immune evasion in vitro and in vivo. Infection of A549 and normal human bronchial cells with 52OmpA2, an ompA mutant, increased the levels of IL-8. 52145-Δwca(K2)ompA, which does not express CPS and ompA, induced the highest levels of IL-8. Both mutants could be complemented. In vivo, 52OmpA2 induced higher levels of tnfα, kc, and il6 than the wild type. ompA mutants activated NF-κB, and the phosphorylation of p38, p44/42, and JNK MAPKs and IL-8 induction was via NF-κB-dependent and p38- and p44/42-dependent pathways. 52OmpA2 engaged TLR2 and -4 to activate NF-κB, whereas 52145-Δwca(K2)ompA activated not only TLR2 and TLR4 but also NOD1. Finally, we demonstrate that the ompA mutant is attenuated in the pneumonia mouse model. The results of this study indicate that K. pneumoniae OmpA contributes to attenuate airway cell responses. This may facilitate pathogen survival in the hostile environment of the lung.
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Affiliation(s)
- Catalina March
- Laboratory of Microbial Pathogenesis, Fundación Caubet-CIMERA Illes Balears, Recinto Hospital Joan March, Carretera Soller Km 12, 07110 Bunyola, Spain
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Bengoechea JA, Ito K. Chronic Obstructive Pulmonary Disease Th1 Cells Display Impaired Response to Endotoxin. Am J Respir Crit Care Med 2011; 183:148-50. [DOI: 10.1164/rccm.201008-1275ed] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Pérez-Bárcena J, Crespí C, Regueiro V, Marsé P, Raurich JM, Ibáñez J, García de Lorenzo-Mateos A, Bengoechea JA. Lack of effect of glutamine administration to boost the innate immune system response in trauma patients in the intensive care unit. Crit Care 2010; 14:R233. [PMID: 21184675 PMCID: PMC3219991 DOI: 10.1186/cc9388] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Revised: 08/03/2010] [Accepted: 12/24/2010] [Indexed: 12/02/2022]
Abstract
Introduction The use of glutamine as a dietary supplement is associated with a reduced risk of infection. We hypothesized that the underlying mechanism could be an increase in the expression and/or functionality of Toll-like receptors (TLR), key receptors sensing infections. The objective of this study was to evaluate whether glutamine supplementation alters the expression and functionality of TLR2 and TLR4 in circulating monocytes of trauma patients admitted to the intensive care unit (ICU). Methods We designed a prospective, randomized and single-blind study. Twenty-three patients received parenteral nutrition (TPN) with a daily glutamine supplement of 0.35 g/kg. The control group (20 patients) received an isocaloric-isonitrogenated TPN. Blood samples were extracted before treatment, at 6 and 14 days. Expression of TLR2 and TLR4 was determined by flow cytometry. Monocytes were stimulated with TLR specific agonists and cytokines were measured in cell culture supernatants. Phagocytic ability of monocytes was also determined. Results Basal characteristics were similar in both groups. Monocytes from patients treated with glutamine expressed the same TLR2 levels as controls before treatment (4.9 ± 3.5 rmfi vs. 4.3 ± 1.9 rmfi, respectively; P = 0.9), at Day 6 (3.8 ± 2.3 rmfi vs. 4.0 ± 1.7 rmfi, respectively; P = 0.7) and at Day 14 (4.1 ± 2.1 rfim vs. 4.6 ± 1.9 rmfi, respectively; P = 0.08). TLR4 levels were not significantly different between the groups before treatment: (1.1 ± 1 rmfi vs 0.9 ± 0.1 rmfi respectively; P = 0.9), at Day 6 (1.1 ± 1 rmfi vs. 0.7 ± 0.4 rmfi respectively; P = 0.1) and at Day 14 (1.4 ± 1.9 rmfi vs. 1.0 ± 0.6 rmfi respectively; P = 0.8). No differences in cell responses to TLR agonists were found between groups. TLR functionality studied by phagocytosis did not vary between groups. Conclusions In trauma patients in the intensive care unit, TPN supplemented with glutamine does not improve the expression or the functionality of TLRs in peripheral blood monocytes. Trial registration ClinicalTrials.gov Identifier: NCT01250080.
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Affiliation(s)
- Jon Pérez-Bárcena
- Intensive Care Medicine Department, Son Dureta University Hospital, Andrea Doria 55, 07014, Palma de Mallorca, Spain.
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Regueiro V, Moranta D, Frank CG, Larrarte E, Margareto J, March C, Garmendia J, Bengoechea JA. Klebsiella pneumoniae subverts the activation of inflammatory responses in a NOD1-dependent manner. Cell Microbiol 2010; 13:135-53. [PMID: 20846183 DOI: 10.1111/j.1462-5822.2010.01526.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Klebsiella pneumoniae is an important cause of community-acquired and nosocomial pneumonia. Subversion of inflammation is essential for pathogen survival during infection. Evidence indicates that K. pneumoniae infections are characterized by lacking an early inflammatory response although the molecular bases are currently unknown. Here we unveil a novel strategy employed by a pathogen to counteract the activation of inflammatory responses. K. pneumoniae attenuates pro-inflammatory mediators-induced IL-8 secretion. Klebsiella antagonizes the activation of NF-κB via the deubiquitinase CYLD and blocks the phosphorylation of mitogen-activated protein kinases (MAPKs) via the MAPK phosphatase MKP-1. Our studies demonstrate that K. pneumoniae has evolved the capacity to manipulate host systems dedicated to control the immune balance. To exert this anti-inflammatory effect, Klebsiella engages NOD1. In NOD1 knock-down cells, Klebsiella neither induces the expression of CYLD and MKP-1 nor blocks the activation of NF-κB and MAPKs. Klebsiella inhibits Rac1 activation; and inhibition of Rac1 activity triggers a NOD1-mediated CYLD and MKP-1 expression which in turn attenuates IL-1β-induced IL-8 secretion. A capsule (CPS) mutant does not attenuate the inflammatory response. However, purified CPS neither reduces IL-1β-induced IL-8 secretion nor induces the expression of CYLD and MKP-1 thereby indicating that CPS is necessary but not sufficient to attenuate inflammation.
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Affiliation(s)
- Verónica Regueiro
- Program Infection and Immunity, Fundació Caubet-CIMERA Illes Balears, Bunyola, Spain
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March C, Regueiro V, Llobet E, Moranta D, Morey P, Garmendia J, Bengoechea JA. Dissection of host cell signal transduction during Acinetobacter baumannii-triggered inflammatory response. PLoS One 2010; 5:e10033. [PMID: 20383325 PMCID: PMC2850920 DOI: 10.1371/journal.pone.0010033] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2009] [Accepted: 03/12/2010] [Indexed: 11/19/2022] Open
Abstract
Infected airway epithelial cells up-regulate the expression of chemokines, chiefly IL-8, and antimicrobial molecules including β-defensins (BD). Acinetobacter baumannii is a cause of hospital-acquired pneumonia. We examined whether A. baumannii induced the expressions of IL-8 and BD2 by airway epithelial cells and the receptors implicated in bacterial detection. A549 and human primary airway cells released IL-8 upon infection. A. baumannii-infected cells also increased the expression of BD2 which killed A. baummannii strains. IL-8 induction was via NF-κB and mitogen-activated kinases p38 and p44/42-dependent pathways. A. baumannii engaged Toll-like receptor (TLR) 2 and TLR4 pathways and A549 cells could use soluble CD14 as TLRs co-receptor. A. baumannii lipopolysaccharide stimulated IL-8 release by A549 cells and sCD14 facilitated the recognition of the lipopolysaccharide. Mass spectrometry analysis revealed that A. baumannii lipid A structure matches those with endotoxic potential. These results demonstrate that airway epithelial cells produce mediators important for A. baumannii clearance.
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Affiliation(s)
- Catalina March
- Program Infection and Immunity, Fundació Caubet-CIMERA Illes Balears, Bunyola, Spain
- Area Molecular Basis of Microbial Pathogenesis, Centro de Investigación Biomédica en Red Enfermedades Respiratorias, Bunyola, Spain
| | - Verónica Regueiro
- Program Infection and Immunity, Fundació Caubet-CIMERA Illes Balears, Bunyola, Spain
- Area Molecular Basis of Microbial Pathogenesis, Centro de Investigación Biomédica en Red Enfermedades Respiratorias, Bunyola, Spain
| | - Enrique Llobet
- Program Infection and Immunity, Fundació Caubet-CIMERA Illes Balears, Bunyola, Spain
- Area Molecular Basis of Microbial Pathogenesis, Centro de Investigación Biomédica en Red Enfermedades Respiratorias, Bunyola, Spain
| | - David Moranta
- Program Infection and Immunity, Fundació Caubet-CIMERA Illes Balears, Bunyola, Spain
- Area Molecular Basis of Microbial Pathogenesis, Centro de Investigación Biomédica en Red Enfermedades Respiratorias, Bunyola, Spain
| | - Pau Morey
- Program Infection and Immunity, Fundació Caubet-CIMERA Illes Balears, Bunyola, Spain
- Area Molecular Basis of Microbial Pathogenesis, Centro de Investigación Biomédica en Red Enfermedades Respiratorias, Bunyola, Spain
| | - Junkal Garmendia
- Program Infection and Immunity, Fundació Caubet-CIMERA Illes Balears, Bunyola, Spain
- Area Molecular Basis of Microbial Pathogenesis, Centro de Investigación Biomédica en Red Enfermedades Respiratorias, Bunyola, Spain
- Instituto de Agrobiotecnología, Pamplona, Spain
| | - José A. Bengoechea
- Program Infection and Immunity, Fundació Caubet-CIMERA Illes Balears, Bunyola, Spain
- Area Molecular Basis of Microbial Pathogenesis, Centro de Investigación Biomédica en Red Enfermedades Respiratorias, Bunyola, Spain
- Área de Microbiología, Facultad Biología, Universitat Illes Balears, Palma Mallorca, Spain
- Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- * E-mail:
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Abstract
Infectious diseases are a leading cause of global human mortality. The use of antimicrobials remains the most common strategy for treatment. However, the isolation of pathogens resistant to virtually all antimicrobials makes it urgent to develop effective therapeutics based on new targets. Here we review a new drug discovery paradigm focusing on identifying and targeting host factors important for infection as well as pathogen determinants involved in disease progression. We summarize innovative strategies which by combining bioinformatics with transcriptomics and chemical genetics have already identified host factors essential for pathogen entry, survival and replication. We describe how the discovery of RNA interference which allows loss-of-function studies has facilitated functional genomic studies in human cells. It is expected that these studies will identify targets to be used as host-directed drug therapy which, together with antimicrobials targeting microbial virulence factors, will efficiently eliminate the invading pathogen.
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Affiliation(s)
- Christian G Frank
- Program Infection and Immunity, Fundación Caubet-CIMERA Illes Balears, Recinto Hospital Joan March, Carretera Soller Km 12, 07110 Bunyola, Spain. Area Molecular basis of microbial pathogenesis, Centro de Investigación Biomédica en Red Enfermedades Respiratorias (CIBERES) Bunyola, Spain. Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
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Regueiro V, Campos MA, Morey P, Sauleda J, Agustí AGN, Garmendia J, Bengoechea JA. Lipopolysaccharide-binding protein and CD14 are increased in the bronchoalveolar lavage fluid of smokers. Eur Respir J 2008; 33:273-81. [PMID: 19010986 DOI: 10.1183/09031936.00087708] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Lipopolysaccharide-binding protein (LBP) and CD14 contribute to the recognition of pathogens by cells, which triggers the activation of defence responses. Smoking is a risk factor for the development of chronic obstructive pulmonary disease (COPD) and respiratory infections. The current authors theorised that levels of LBP and CD14 in the lungs of smokers would be higher than those in the lungs of never-smokers. These elevated levels could affect host responses upon infection. LBP, soluble CD14 (sCD14) and interleukin (IL)-8 were detected by ELISA. Nuclear factor (NF)-kappaB, p38 and the inhibitor IkappaBalpha were studied by immunoassays. Gene expression was assessed by RT-PCR. Bronchoalveolar lavage levels of LBP and CD14 were significantly higher in smokers and COPD patients than in never-smokers, whereas levels of both proteins were not significantly different between smokers and COPD patients. IL-6, IL-1beta and cigarette smoke condensate induced the expression of LBP and CD14 by airway epithelial cells. LBP and sCD14 inhibited the nontypeable Haemophilus influenzae (NTHi)-dependent secretion of IL-8 and the activation of NF-kappaB and p38 mitogen-activated protein kinase signalling pathways but they increased the internalisation of NTHi by airway epithelial cells. Thus, in the inflamed airways of smokers both proteins could contribute to inhibit bacteria-dependent cellular activation without compromising the internalisation of pathogens by airway cells.
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Affiliation(s)
- V Regueiro
- Program Infection and Immunity, Fundació Caubet-CIMERA Illes Balears, Recinto Hospital Joan March, Carretera Sóller Km 12, 07110 Bunyola, Spain
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Pérez-Gutiérrez C, Llompart CM, Skurnik M, Bengoechea JA. Expression of the Yersinia enterocolitica pYV-encoded type III secretion system is modulated by lipopolysaccharide O-antigen status. Infect Immun 2007; 75:1512-6. [PMID: 17178779 PMCID: PMC1828576 DOI: 10.1128/iai.00942-06] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2006] [Revised: 07/24/2006] [Accepted: 12/11/2006] [Indexed: 01/24/2023] Open
Abstract
We show that the expression of a Yersinia enterocolitica O:8 pYV-encoded type III secretion system was altered in a rough mutant (YeO8-R) due to elevated levels of FlhDC. H-NS might underlie flhDC upregulation in YeO8-R, and the data suggest a relationship between the absence of O antigen and the expression of H-NS.
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Affiliation(s)
- Camino Pérez-Gutiérrez
- Fundació Caubet-CIMERA Illes Balears, Recinto Hospital Joan March, Carretera Soller km 12, 07110 Bunyola, Spain
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Abstract
The treatment of infections caused by bacteria resistant to the vast majority of antibiotics is a challenge worldwide. Antimicrobial peptides (APs) make up the front line of defense in those areas exposed to microorganisms, and there is intensive research to explore their use as new antibacterial agents. On the other hand, it is known that subinhibitory concentrations of antibiotics affect the expression of numerous bacterial traits. In this work we evaluated whether treatment of bacteria with subinhibitory concentrations of quinolones may alter the sensitivity to APs. A 1-h treatment of Klebsiella pneumoniae with 0.25 x the MIC of ciprofloxacin rendered bacteria more sensitive to polymyxins B and E, human neutrophil defensin 1, and beta-defensin 1. Levofloxacin and nalidixic acid at 0.25 x the MICs also increased the sensitivity of K. pneumoniae to polymyxin B, whereas gentamicin and ceftazidime at 0.25 x the MICs did not have such an effect. Ciprofloxacin also increased the sensitivities of K. pneumoniae ciprofloxacin-resistant strains to polymyxin B. Two other pathogens, Pseudomonas aeruginosa and Haemophilus influenzae, also became more sensitive to polymyxins B and E after treatment with 0.25 x the MIC of ciprofloxacin. Incubation with ciprofloxacin did not alter the expression of the K. pneumoniae loci involved in resistance to APs. A 1-N-phenyl-naphthylamine assay showed that ciprofloxacin and levofloxacin increased the permeabilities of the K. pneumoniae and P. aeruginosa outer membranes, while divalent cations antagonized this action. Finally, we demonstrated that ciprofloxacin and levofloxacin increased the binding of APs to the outer membrane by using dansylated polymyxin B.
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Affiliation(s)
- Miguel A Campos
- Unidad de Investigación, Hospital Universitario Son Dureta, and Institut Universitari d'Investigacions en Ciències de la Salut (IUNICS), Palma de Mallorca, Spain
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Pons J, Sauleda J, Regueiro V, Santos C, López M, Ferrer J, Agustí AGN, Bengoechea JA. Expression of Toll-like receptor 2 is up-regulated in monocytes from patients with chronic obstructive pulmonary disease. Respir Res 2006; 7:64. [PMID: 16606450 PMCID: PMC1458333 DOI: 10.1186/1465-9921-7-64] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2005] [Accepted: 04/10/2006] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Chronic obstructive pulmonary disease (COPD) is characterised by pulmonary and systemic inflammation which flare-up during episodes of acute exacerbation (AECOPD). Given the role of Toll-like receptors (TLRs) in the induction of inflammatory responses we investigated the involvement of TLRs in COPD pathogenesis. METHODS The expression of TLR-2, TLR-4 and CD14 in monocytes was analyzed by flow cytometry. To study the functional responses of these receptors, monocytes were stimulated with peptidoglycan or lipopolysaccharide and the amounts of TNFalpha and IL-6 secreted were determined by ELISA. RESULTS We found that the expression of TLR-2 was up-regulated in peripheral blood monocytes from COPD patients, either clinically stable or during AECOPD, as compared to never smokers or smokers with normal lung function. Upon stimulation with TLR-2 ligand monocytes from COPD patients secreted increased amounts of cytokines than similarly stimulated monocytes from never smokers and smokers. In contrast, the expressions of TLR-4 and CD14 were not significantly different between groups, and the response to lipopolysaccharide (a TLR-4 ligand) stimulation was not significantly different either. At discharge from hospital TLR-2 expression was down-regulated in peripheral blood monocytes from AECOPD patients. This could be due to the treatment with systemic steroids because, in vitro, steroids down-regulated TLR-2 expression in a dose-dependent manner. Finally, we demonstrated that IL-6, whose plasma levels are elevated in patients, up-regulated in vitro TLR-2 expression in monocytes from never smokers. CONCLUSION Our results reveal abnormalities in TLRs expression in COPD patients and highlight its potential relationship with systemic inflammation in these patients.
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Affiliation(s)
- Jaume Pons
- Unidad de Investigación, Hospital Son Dureta, Institut Universitari d'Investigacions en Ciències de la Salut (IUNICS), Palma Mallorca, Spain
- Servicio de Inmunología, Hospital Son Dureta, Palma Mallorca, Spain
| | - Jaume Sauleda
- Servicio de Neumología, Hospital Son Dureta, Palma Mallorca, Spain
| | - Verónica Regueiro
- Program Infection and Immunity, Fundació Caubet-CIMERA Illes Balears, Bunyola, Spain
| | - Carmen Santos
- Unidad de Investigación, Hospital Son Dureta, Institut Universitari d'Investigacions en Ciències de la Salut (IUNICS), Palma Mallorca, Spain
| | - Meritxell López
- Servicio de Neumología, Hospital Son Dureta, Palma Mallorca, Spain
| | - Joana Ferrer
- Servicio de Inmunología, Hospital Son Dureta, Palma Mallorca, Spain
| | - Alvar GN Agustí
- Program Infection and Immunity, Fundació Caubet-CIMERA Illes Balears, Bunyola, Spain
- Servicio de Neumología, Hospital Son Dureta, Palma Mallorca, Spain
| | - José A Bengoechea
- Unidad de Investigación, Hospital Son Dureta, Institut Universitari d'Investigacions en Ciències de la Salut (IUNICS), Palma Mallorca, Spain
- Program Infection and Immunity, Fundació Caubet-CIMERA Illes Balears, Bunyola, Spain
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Regueiro V, Campos MA, Pons J, Albertí S, Bengoechea JA. The uptake of a Klebsiella pneumoniae capsule polysaccharide mutant triggers an inflammatory response by human airway epithelial cells. Microbiology (Reading) 2006; 152:555-566. [PMID: 16436443 DOI: 10.1099/mic.0.28285-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The means by which airway epithelial cells sense a bacterial infection and which intracellular signalling pathways are activated upon infection are poorly understood. A549 cells and human primary airway cells (NHBE) were used to investigate the response to infection withKlebsiella pneumoniae. Infection of A549 and NHBE withK. pneumoniae52K10, a capsule polysaccharide (CPS) mutant, increased the surface levels of ICAM-1 and caused the release of IL-8. By contrast, the wild-type strain did not elicit these responses. Consistent with a functional role for these responses, there was a correlation between ICAM-1 levels and the number of adherent leukocytes on the epithelial cell surface. In addition, treatment of neutrophils with IL-8 enhanced their ability to killK. pneumoniae. Strain 52K10 was internalized by A549 cells more efficiently than the wild-type, and when infections with 52K10 were performed in the presence of cytochalasin D the inflammatory response was abrogated. These findings suggest that cellular activation is mediated by bacterial internalization and that CPS prevents the activation through the blockage of bacterial adhesion and uptake. Collectively, the results indicate that bacterial internalization by airway epithelial cells could be the triggering signal for the activation of the innate immune system of the airway. Infection of A549 cells by 52K10 was shown to trigger the nuclear translocation of NF-κB. Evidence is presented showing that 52K10 activated IL-8 production through Toll-like receptor (TLR) 2 and TLR4 pathways and that A549 cells could use soluble CD14 as TLR co-receptor.
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Affiliation(s)
- Verónica Regueiro
- Institut Universitari d'Investigacions en Ciències de la Salut (IUNICS), Palma de Mallorca, Spain
- Unidad de Investigación, Hospital Universitario Son Dureta, Andrea Doria 55, 07014 Palma Mallorca, Spain
| | - Miguel A Campos
- Institut Universitari d'Investigacions en Ciències de la Salut (IUNICS), Palma de Mallorca, Spain
- Unidad de Investigación, Hospital Universitario Son Dureta, Andrea Doria 55, 07014 Palma Mallorca, Spain
| | - Jaume Pons
- Institut Universitari d'Investigacions en Ciències de la Salut (IUNICS), Palma de Mallorca, Spain
- Servicio de Inmunología, Hospital Universitario Son Dureta, Andrea Doria 55, 07014 Palma Mallorca, Spain
| | - Sebastián Albertí
- Área de Microbiología, Departamento de Biología, Universidad de las Islas Baleares, Palma de Mallorca, Spain
- Institut Universitari d'Investigacions en Ciències de la Salut (IUNICS), Palma de Mallorca, Spain
| | - José A Bengoechea
- Institut Universitari d'Investigacions en Ciències de la Salut (IUNICS), Palma de Mallorca, Spain
- Unidad de Investigación, Hospital Universitario Son Dureta, Andrea Doria 55, 07014 Palma Mallorca, Spain
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Abstract
The innate immune system plays a critical role in the defense of areas exposed to microorganisms. There is an increasing body of evidence indicating that antimicrobial peptides and proteins (APs) are one of the most important weapons of this system and that they make up the protective front for the respiratory tract. On the other hand, it is known that pathogenic organisms have developed countermeasures to resist these agents such as reducing the net negative charge of the bacterial membranes. Here we report the characterization of a novel mechanism of resistance to APs that is dependent on the bacterial capsule polysaccharide (CPS). Klebsiella pneumoniae CPS mutant was more sensitive than the wild type to human neutrophil defensin 1, beta-defensin 1, lactoferrin, protamine sulfate, and polymyxin B. K. pneumoniae lipopolysaccharide O antigen did not play an important role in AP resistance, and CPS was the only factor conferring protection against polymyxin B in strains lacking O antigen. In addition, we found a significant correlation between the amount of CPS expressed by a given strain and the resistance to polymyxin B. We also showed that K. pneumoniae CPS mutant bound more polymyxin B than the wild-type strain with a concomitant increased in the self-promoted pathway. Taken together, our results suggest that CPS protects bacteria by limiting the interaction of APs with the surface. Finally, we report that K. pneumoniae increased the amount of CPS and upregulated cps transcription when grown in the presence of polymyxin B and lactoferrin.
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Affiliation(s)
- Miguel A Campos
- Unidad de Investigación, Hospital Son Dureta, Andrea Doria 55, 07014 Palma Mallorca, Spain
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37
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Abstract
Lipopolysaccharide (LPS) is the major component of the outer leaflet of the outer membrane of Gram-negative bacteria. The LPS molecule is composed of two biosynthetic entities: the lipid A--core and the O-polysaccharide (O-antigen). Most biological effects of LPS are due to the lipid A part, however, there is an increasing body of evidence indicating that O-antigen (O-ag) plays an important role in effective colonization of host tissues, resistance to complement-mediated killing and in the resistance to cationic antimicrobial peptides that are key elements of the innate immune system. In this review, we will discuss: (i) the work done on the genetics and biosynthesis of the O-ags in the genus Yersinia; (ii) the role of O-ag in virulence of these bacteria; (iii) the work done on regulation of the O-ag gene cluster expression and; (iv) the impact that the O-ag expression has on other bacterial surface and membrane components.
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Affiliation(s)
- Mikael Skurnik
- Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki and Helsinki University Central Hospital Laboratory Diagnostics, P.O. Box 63, FIN-00014 Helsinki, Finland.
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Najdenski H, Golkocheva E, Vesselinova A, Bengoechea JA, Skurnik M. Proper expression of the O-antigen of lipopolysaccharide is essential for the virulence of Yersinia enterocolitica O:8 in experimental oral infection of rabbits. FEMS Immunol Med Microbiol 2003; 38:97-106. [PMID: 13129643 DOI: 10.1016/s0928-8244(03)00183-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The O-antigen of lipopolysaccharide (LPS) is required for virulence in Yersinia enterocolitica serotype O:8. Here we evaluated the importance of controlling the O-antigen biosynthesis using an in vivo rabbit model of infection. Y. enterocolitica O:8 wild-type strain was compared to three mutants differing in the O-antigen phenotype: (i) the rough strain completely devoid of the O-antigen, (ii) the wzy strain that lacks the O-antigen polymerase (Wzy protein) and expresses LPS with only one repeat unit, and (iii) the wzz strain that lacks the O-antigen chain length determinant (Wzz protein) and expresses LPS without modal distribution of O-antigen chain lengths. The most attenuated strain was the wzz mutant. The wzz bacteria were cleared from the tissues by day 30, the blood parameters were least dramatic and histologically only immunomorphological findings were seen. The level of attenuation of the rough and the wzy strain bacteria was between the wild-type and the wzz strain. Wild-type bacteria were highly resistant to killing by polymorphonuclear leukocytes, the wzz strain bacteria were most sensitive and the rough and wzy strain bacteria were intermediate resistant. These results clearly demonstrated that the presence of O-antigen on the bacterial surface is not alone sufficient for full virulence, but also there is a requirement for its controlled chain length.
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Affiliation(s)
- H Najdenski
- The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria.
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Bengoechea JA, Brandenburg K, Arraiza MD, Seydel U, Skurnik M, Moriyón I. Pathogenic Yersinia enterocolitica strains increase the outer membrane permeability in response to environmental stimuli by modulating lipopolysaccharide fluidity and lipid A structure. Infect Immun 2003; 71:2014-21. [PMID: 12654821 PMCID: PMC152087 DOI: 10.1128/iai.71.4.2014-2021.2003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Pathogenic biotypes of Yersinia enterocolitica (serotypes O:3, O:8, O:9, and O:13), but not environmental biotypes (serotypes O:5, O:6, O:7,8, and O:7,8,13,19), increased their permeability to hydrophobic probes when they were grown at pH 5.5 or in EGTA-supplemented (Ca(2+)-restricted) media at 37 degrees C. A similar observation was also made when representative strains of serotypes O:8 and O:5 were tested after brief contact with human monocytes. The increase in permeability was independent of the virulence plasmid. The role of lipopolysaccharide (LPS) in this phenomenon was examined by using Y. enterocolitica serotype O:8. LPS aggregates of bacteria grown in acidic or EGTA-supplemented broth took up more N-phenylnaphthylamine than LPS aggregates of bacteria grown in standard broth and also showed a marked increase in acyl chain fluidity which correlated with permeability, as determined by measurements obtained in the presence of hydrophobic dyes. No significant changes in O-antigen polymerization were observed, but lipid A acylation changed depending on the growth conditions. In standard medium at 37 degrees C, there were hexa-, penta-, and tetraacyl lipid A forms, and the pentaacyl form was dominant. The amount of tetraacyl lipid A increased in EGTA-supplemented and acidic media, and hexaacyl lipid A almost disappeared under the latter conditions. Our results suggest that pathogenic Y. enterocolitica strains modulate lipid A acylation coordinately with expression of virulence proteins, thus reducing LPS packing and increasing outer membrane permeability. The changes in permeability, LPS acyl chain fluidity, and lipid A acylation in pathogenic Y. enterocolitica strains approximate the characteristics in Yersinia pseudotuberculosis and Yersinia pestis and suggest that there is a common outer membrane pattern associated with pathogenicity.
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Affiliation(s)
- J A Bengoechea
- Department of Microbiology, University of Navarra, 31080 Pamplona, Spain
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Pio R, Martinez A, Unsworth EJ, Kowalak JA, Bengoechea JA, Zipfel PF, Elsasser TH, Cuttitta F. Complement factor H is a serum-binding protein for adrenomedullin, and the resulting complex modulates the bioactivities of both partners. J Biol Chem 2001; 276:12292-300. [PMID: 11116141 DOI: 10.1074/jbc.m007822200] [Citation(s) in RCA: 192] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Adrenomedullin (AM) is an important regulatory peptide involved in both physiological and pathological states. We have previously demonstrated the existence of a specific AM-binding protein (AMBP-1) in human plasma. In the present study, we developed a nonradioactive ligand blotting assay, which, together with high pressure liquid chromatography/SDS-polyacrylamide gel electrophoresis purification techniques, allowed us to isolate AMBP-1 to homogeneity. The purified protein was identified as human complement factor H. We show that AM/factor H interaction interferes with the established methodology for quantification of circulating AM. Our data suggest that this routine procedure does not take into account the AM bound to its binding protein. In addition, we show that factor H affects AM in vitro functions. It enhances AM-mediated induction of cAMP in fibroblasts, augments the AM-mediated growth of a cancer cell line, and suppresses the bactericidal capability of AM on Escherichia coli. Reciprocally, AM influences the complement regulatory function of factor H by enhancing the cleavage of C3b via factor I. In summary, we report on a potentially new regulatory mechanism of AM biology, the influence of factor H on radioimmunoassay quantification of AM, and the possible involvement of AM as a regulator of the complement cascade.
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Affiliation(s)
- R Pio
- Department of Cell and Cancer Biology, NCI, National Institutes of Health, Bethesda, Maryland 20892, USA
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Abstract
Most bacterial pathogens are resistant to cationic antimicrobial peptides (CAMPs) that are key components of the innate immunity of both vertebrates and invertebrates. In Gram-negative bacteria, the known CAMPs resistance mechanisms involve outer membrane (OM) modifications and specifically those in the lipopolysaccharide (LPS) molecule. Here we report, the characterization of a novel CAMPs resistance mechanism present in Yersinia that is dependent on an efflux pump/potassium antiporter system formed by the RosA and RosB proteins. The RosA/RosB system is activated by a temperature shift to 37 degrees C, but is also induced by the presence of the CAMPs, such as polymyxin B. This is the first report of a CAMPs resistance system that is induced by the presence of CAMPs. It is proposed that the RosA/RosB system protects the bacteria by both acidifying the cytoplasm to prevent the CAMPs action and pumping the CAMPs out of the cell.
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Affiliation(s)
- J A Bengoechea
- Department of Medical Biochemistry, Institute of Biomedicine, University of Turku, Kiinamyllynkatu 10, FIN-20520 Turku, Finland
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Velasco J, Bengoechea JA, Brandenburg K, Lindner B, Seydel U, González D, Zähringer U, Moreno E, Moriyón I. Brucella abortus and its closest phylogenetic relative, Ochrobactrum spp., differ in outer membrane permeability and cationic peptide resistance. Infect Immun 2000; 68:3210-8. [PMID: 10816465 PMCID: PMC97564 DOI: 10.1128/iai.68.6.3210-3218.2000] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The outer membrane (OM) of the intracellular parasite Brucella abortus is permeable to hydrophobic probes and resistant to destabilization by polycationic peptides and EDTA. The significance of these unusual properties was investigated in a comparative study with the opportunistic pathogens of the genus Ochrobactrum, the closest known Brucella relative. Ochrobactrum spp. OMs were impermeable to hydrophobic probes and sensitive to polymyxin B but resistant to EDTA. These properties were traced to lipopolysaccharide (LPS) because (i) insertion of B. abortus LPS, but not of Escherichia coli LPS, into Ochrobactrum OM increased its permeability; (ii) permeability and polymyxin B binding measured with LPS aggregates paralleled the results with live bacteria; and (iii) the predicted intermediate results were obtained with B. abortus-Ochrobactrum anthropi and E. coli-O. anthropi LPS hybrid aggregates. Although Ochrobactrum was sensitive to polymyxin, self-promoted uptake and bacterial lysis occurred without OM morphological changes, suggesting an unusual OM structural rigidity. Ochrobactrum and B. abortus LPSs showed no differences in phosphate, qualitative fatty acid composition, or acyl chain fluidity. However, Ochrobactrum LPS, but not B. abortus LPS, contained galacturonic acid. B. abortus and Ochrobactrum smooth LPS aggregates had similar size and zeta potential (-12 to -15 mV). Upon saturation with polymyxin, zeta potential became positive (1 mV) for Ochrobactrum smooth LPS while remaining negative (-5 mV) for B. abortus smooth LPS, suggesting hindered access to inner targets. These results show that although Ochrobactrum and Brucella share a basic OM pattern, subtle modifications in LPS core cause markedly different OM properties, possibly reflecting the adaptive evolution of B. abortus to pathogenicity.
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Affiliation(s)
- J Velasco
- Departamento de Microbiología, Universidad de Navarra, Pamplona, Spain
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43
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Freer E, Pizarro-Cerdá J, Weintraub A, Bengoechea JA, Moriyón I, Hultenby K, Gorvel JP, Moreno E. The outer membrane of Brucella ovis shows increased permeability to hydrophobic probes and is more susceptible to cationic peptides than are the outer membranes of mutant rough Brucella abortus strains. Infect Immun 1999; 67:6181-6. [PMID: 10531286 PMCID: PMC97012 DOI: 10.1128/iai.67.11.6181-6186.1999] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The permeability of the outer membrane (OM) to hydrophobic probes and its susceptibility to bactericidal cationic peptides were investigated for natural rough Brucella ovis and for mutant rough Brucella abortus strains. The OM of B. ovis displayed an abrupt and faster kinetic profile than rough B. abortus during the uptake of the hydrophobic probe N-phenyl-naphthylamine. B. ovis was more sensitive than rough B. abortus to the action of cationic peptides. Bactenecins 5 and 7 induced morphological alterations on the OMs of both rough Brucella strains. B. ovis lipopolysaccharide (LPS) captured considerably more polymyxin B than LPSs from both rough and smooth B. abortus strains. Polymyxin B, poly-L-lysine, and poly-L-ornithine produced a thick coating on the surfaces of both strains, which was more evident in B. ovis than in rough B. abortus. The distinct functional properties of the OMs of these two rough strains correlate with some structural differences of their OMs and with their different biological behaviors in animals and culture cells.
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Affiliation(s)
- E Freer
- Unidad de Microscopía Electrónica, Universidad de Costa Rica, San José, Heredia, Costa Rica
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Skurnik M, Venho R, Bengoechea JA, Moriyón I. The lipopolysaccharide outer core of Yersinia enterocolitica serotype O:3 is required for virulence and plays a role in outer membrane integrity. Mol Microbiol 1999; 31:1443-62. [PMID: 10200964 DOI: 10.1046/j.1365-2958.1999.01285.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Lipopolysaccharide (LPS) of Yersinia enterocolitica O:3 has an inner core linked to both the O-antigen and to an outer core hexasaccharide that forms a branch. The biological role of the outer core was studied using polar and non-polar mutants of the outer core biosynthetic operon. Analysis of O-antigen- and outer core-deficient strains suggested a critical role for the outer core in outer membrane properties relevant in resistance to antimicrobial peptides and permeability to hydrophobic agents, and indirectly relevant in resistance to killing by normal serum. Wild-type bacteria but not outer core mutants killed intragastrically infected mice, and the intravenous lethal dose was approximately 10(4)-fold higher for outer core mutants. After intragastric infection, outer core mutants colonized Peyer's patches and invaded mesenteric lymph nodes, spleen and liver, and induced protective immunity against wild-type bacteria. In mice co-infected intragastrically with an outer core mutant-wild type mixture, both strains colonized Peyer's patches similarly during the first 2 days, but the mutant was much less efficient in colonizing deeper organs and was cleared faster from Peyer's patches. The results demonstrate that outer core is required for Y. enterocolitica O:3 full virulence, and strongly suggest that it provides resistance against defence mechanisms (most probably those involving bactericidal peptides).
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Affiliation(s)
- M Skurnik
- Department of Medical Biochemistry, University of Turku, Finland.
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Páramo L, Lomonte B, Pizarro-Cerdá J, Bengoechea JA, Gorvel JP, Moreno E. Bactericidal activity of Lys49 and Asp49 myotoxic phospholipases A2 from Bothrops asper snake venom--synthetic Lys49 myotoxin II-(115-129)-peptide identifies its bactericidal region. Eur J Biochem 1998; 253:452-61. [PMID: 9654096 DOI: 10.1046/j.1432-1327.1998.2530452.x] [Citation(s) in RCA: 144] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mammalian group-II phospholipases A2 (PLA2) of inflammatory fluids display bactericidal properties, which are dependent on their enzymatic activity. This study shows that myotoxins II (Lys49) and III (Asp49), two group-II PLA2 isoforms from the venom of Bothrops asper, are lethal to a broad spectrum of bacteria. Since the catalytically inactive Lys49 myotoxin II isoform has similar bactericidal effects to its catalytically active Asp49 counterpart, a bactericidal mechanism that is independent of an intrinsic PLA2 activity is demonstrated. Moreover, a synthetic 13-residue peptide of myotoxin II, comprising residues 115-129 (common numbering system) near the C-terminal loop, reproduced the bactericidal effect of the intact protein. Following exposure to the peptide or the protein, accelerated uptake of the hydrophobic probe N-phenyl-N-naphthylamine was observed in susceptible but not in resistant bacteria, indicating that the lethal effect was initiated on the bacterial membrane. The outer membrane, isolated lipopolysaccharide (LPS), and lipid A of susceptible bacteria showed higher binding to the myotoxin II-(115-129)-peptide than the corresponding moieties of resistant strains. Bacterial LPS chimeras indicated that LPS is a relevant target for myotoxin II-(115-129)-peptide. When heterologous LPS of the resistant strain was present in the context of susceptible bacteria, the chimera became resistant, and vice versa. Myotoxin II represents a group-II PLA2 with a direct bactericidal effect that is independent of an intrinsic enzymatic activity, but adscribed to the presence of a short cluster of basic/hydrophobic amino acids near its C-terminal loop.
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Affiliation(s)
- L Páramo
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
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Bengoechea JA, Díaz R, Moriyón I. Outer membrane differences between pathogenic and environmental Yersinia enterocolitica biogroups probed with hydrophobic permeants and polycationic peptides. Infect Immun 1996; 64:4891-9. [PMID: 8945523 PMCID: PMC174465 DOI: 10.1128/iai.64.12.4891-4899.1996] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Sensitivities to polycationic peptides and EDTA were compared in Yersinia enterocolitica pathogenic and environmental biogroups. As shown by changes in permeability to the fluorescent hydrophobic probe N-phenylnaphthylamine (NPN), the outer membranes (OMs) of pathogenic and environmental strains grown at 26 degrees C in standard broth were more resistant to poly-L-lysine, poly-L-ornithine, melittin, cecropin P1, polymyxin B, and EDTA than Escherichia coli OMs. At 37 degrees C, OMs of pathogenic biogroups were resistant to EDTA and polycations and OMs of environmental strains were resistant to EDTA whereas E. coli OMs were sensitive to both EDTA and polycations. Similar results were found when testing deoxycholate sensitivity after polycation exposure or when isogenic pairs with or without virulence plasmid pYV were compared. With bacteria grown without Ca++ available, OM permeability to NPN was drastically increased in pathogenic but not in environmental strains or E. coli. Under these conditions, OMs of pYV+ and pYV- cells showed small differences in NPN permeability but differences in polycation sensitivity could not be detected by fluorimetry. O:1,6 (environmental type) lipopolysaccharide (LPS), but not O:3 or O:8 LPS, was markedly rough at 37 degrees C, and this could explain the differences in polycation sensitivity. LPSs from serotypes O:3 and O:8 grown at 37 degrees C were more permeable to NPN than O:1,6 LPS, and O:8 LPS was resistant to polycation-induced permeabilization. These data suggest that LPSs relate to some but not all the OM differences described. It is hypothesized that the different OM properties of environmental and pathogenic biogroups reflect the adaptation of the latter biogroups to pathogenicity.
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Affiliation(s)
- J A Bengoechea
- Departamento de Microbiologia, Universidad de Navarra, Pamplona, Spain
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