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Mangoni ML, Loffredo MR, Casciaro B, Ferrera L, Cappiello F. An Overview of Frog Skin-Derived Esc Peptides: Promising Multifunctional Weapons against Pseudomonas aeruginosa-Induced Pulmonary and Ocular Surface Infections. Int J Mol Sci 2024; 25:4400. [PMID: 38673985 PMCID: PMC11049899 DOI: 10.3390/ijms25084400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 04/08/2024] [Accepted: 04/13/2024] [Indexed: 04/28/2024] Open
Abstract
Antimicrobial resistance is a silent pandemic harming human health, and Pseudomonas aeruginosa is the most common bacterium responsible for chronic pulmonary and eye infections. Antimicrobial peptides (AMPs) represent promising alternatives to conventional antibiotics. In this review, the in vitro/in vivo activities of the frog skin-derived AMP Esc(1-21) are shown. Esc(1-21) rapidly kills both the planktonic and sessile forms of P. aeruginosa and stimulates migration of epithelial cells, likely favoring repair of damaged tissue. However, to undertake preclinical studies, some drawbacks of AMPs (cytotoxicity, poor biostability, and limited delivery to the target site) must be overcome. For this purpose, the stereochemistry of two amino acids of Esc(1-21) was changed to obtain the diastereomer Esc(1-21)-1c, which is more stable, less cytotoxic, and more efficient in treating P. aeruginosa-induced lung and cornea infections in mouse models. Incorporation of these peptides (Esc peptides) into nanoparticles or immobilization to a medical device (contact lens) was revealed to be an effective strategy to ameliorate and/or to prolong the peptides' antimicrobial efficacy. Overall, these data make Esc peptides encouraging candidates for novel multifunctional drugs to treat lung pathology especially in patients with cystic fibrosis and eye dysfunctions, characterized by both tissue injury and bacterial infection.
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Affiliation(s)
- Maria Luisa Mangoni
- Laboratory Affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, 00185 Rome, Italy
| | - Maria Rosa Loffredo
- Laboratory Affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, 00185 Rome, Italy
| | - Bruno Casciaro
- Laboratory Affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, 00185 Rome, Italy
| | - Loretta Ferrera
- UOC Genetica Medica, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy
| | - Floriana Cappiello
- Laboratory Affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, 00185 Rome, Italy
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2
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Grandy S, Scur M, Dolan K, Nickerson R, Cheng Z. Using model systems to unravel host-Pseudomonas aeruginosa interactions. Environ Microbiol 2023; 25:1765-1784. [PMID: 37290773 DOI: 10.1111/1462-2920.16440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 05/29/2023] [Indexed: 06/10/2023]
Abstract
Using model systems in infection biology has led to the discoveries of many pathogen-encoded virulence factors and critical host immune factors to fight pathogenic infections. Studies of the remarkable Pseudomonas aeruginosa bacterium that infects and causes disease in hosts as divergent as humans and plants afford unique opportunities to shed new light on virulence strategies and host defence mechanisms. One of the rationales for using model systems as a discovery tool to characterise bacterial factors driving human infection outcomes is that many P. aeruginosa virulence factors are required for pathogenesis in diverse different hosts. On the other side, many host signalling components, such as the evolutionarily conserved mitogen-activated protein kinases, are involved in immune signalling in a diverse range of hosts. Some model organisms that have less complex immune systems also allow dissection of the direct impacts of innate immunity on host defence without the interference of adaptive immunity. In this review, we start with discussing the occurrence of P. aeruginosa in the environment and the ability of this bacterium to cause disease in various hosts as a natural opportunistic pathogen. We then summarise the use of some model systems to study host defence and P. aeruginosa virulence.
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Affiliation(s)
- Shannen Grandy
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Michal Scur
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Kathleen Dolan
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Rhea Nickerson
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Zhenyu Cheng
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
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3
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Jordana-Lluch E, Barceló IM, Escobar-Salom M, Estévez MA, Zamorano L, Gómez-Zorrilla S, Sendra E, Oliver A, Juan C. The balance between antibiotic resistance and fitness/virulence in Pseudomonas aeruginosa: an update on basic knowledge and fundamental research. Front Microbiol 2023; 14:1270999. [PMID: 37840717 PMCID: PMC10569695 DOI: 10.3389/fmicb.2023.1270999] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 09/15/2023] [Indexed: 10/17/2023] Open
Abstract
The interplay between antibiotic resistance and bacterial fitness/virulence has attracted the interest of researchers for decades because of its therapeutic implications, since it is classically assumed that resistance usually entails certain biological costs. Reviews on this topic revise the published data from a general point of view, including studies based on clinical strains or in vitro-evolved mutants in which the resistance phenotype is seen as a final outcome, i.e., a combination of mechanisms. However, a review analyzing the resistance/fitness balance from the basic research perspective, compiling studies in which the different resistance pathways and respective biological costs are individually approached, was missing. Here we cover this gap, specifically focusing on Pseudomonas aeruginosa, a pathogen that stands out because of its extraordinary capacity for resistance development and for which a considerable number of recent and particular data on the interplay with fitness/virulence have been released. The revised information, split into horizontally-acquired vs. mutation-driven resistance, suggests a great complexity and even controversy in the resistance-fitness/virulence balance in the acute infection context, with results ranging from high costs linked to certain pathways to others that are seemingly cost-free or even cases of resistance mechanisms contributing to increased pathogenic capacities. The elusive mechanistic basis for some enigmatic data, knowledge gaps, and possibilities for therapeutic exploitation are discussed. The information gathered suggests that resistance-fitness/virulence interplay may be a source of potential antipseudomonal targets and thus, this review poses the elementary first step for the future development of these strategies harnessing certain resistance-associated biological burdens.
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Affiliation(s)
- Elena Jordana-Lluch
- Research Unit, University Hospital Son Espases-Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain
- Department of Microbiology, University Hospital Son Espases, Palma, Spain
- Centro de Investigación Biomédica en Red, Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
| | - Isabel Mª Barceló
- Research Unit, University Hospital Son Espases-Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain
- Department of Microbiology, University Hospital Son Espases, Palma, Spain
- Centro de Investigación Biomédica en Red, Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
| | - María Escobar-Salom
- Research Unit, University Hospital Son Espases-Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain
- Department of Microbiology, University Hospital Son Espases, Palma, Spain
- Centro de Investigación Biomédica en Red, Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
| | - Miguel A. Estévez
- Research Unit, University Hospital Son Espases-Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain
- Department of Microbiology, University Hospital Son Espases, Palma, Spain
| | - Laura Zamorano
- Research Unit, University Hospital Son Espases-Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain
- Department of Microbiology, University Hospital Son Espases, Palma, Spain
- Centro de Investigación Biomédica en Red, Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
| | - Silvia Gómez-Zorrilla
- Centro de Investigación Biomédica en Red, Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
- Infectious Diseases Service, Hospital del Mar, Hospital del Mar Research Institute, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Universitat Autònoma de Barcelóna (UAB), Barcelona, Spain
| | - Elena Sendra
- Infectious Diseases Service, Hospital del Mar, Hospital del Mar Research Institute, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Universitat Autònoma de Barcelóna (UAB), Barcelona, Spain
| | - Antonio Oliver
- Research Unit, University Hospital Son Espases-Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain
- Department of Microbiology, University Hospital Son Espases, Palma, Spain
- Centro de Investigación Biomédica en Red, Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
| | - Carlos Juan
- Research Unit, University Hospital Son Espases-Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain
- Department of Microbiology, University Hospital Son Espases, Palma, Spain
- Centro de Investigación Biomédica en Red, Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
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4
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Vines JH, Maib H, Buckley CM, Gueho A, Zhu Z, Soldati T, Murray DH, King JS. A PI(3,5)P2 reporter reveals PIKfyve activity and dynamics on macropinosomes and phagosomes. J Cell Biol 2023; 222:e202209077. [PMID: 37382666 PMCID: PMC10309190 DOI: 10.1083/jcb.202209077] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 05/12/2023] [Accepted: 06/13/2023] [Indexed: 06/30/2023] Open
Abstract
Phosphoinositide signaling lipids (PIPs) are key regulators of membrane identity and trafficking. Of these, PI(3,5)P2 is one of the least well-understood, despite key roles in many endocytic pathways including phagocytosis and macropinocytosis. PI(3,5)P2 is generated by the phosphoinositide 5-kinase PIKfyve, which is critical for phagosomal digestion and antimicrobial activity. However PI(3,5)P2 dynamics and regulation remain unclear due to lack of reliable reporters. Using the amoeba Dictyostelium discoideum, we identify SnxA as a highly selective PI(3,5)P2-binding protein and characterize its use as a reporter for PI(3,5)P2 in both Dictyostelium and mammalian cells. Using GFP-SnxA, we demonstrate that Dictyostelium phagosomes and macropinosomes accumulate PI(3,5)P2 3 min after engulfment but are then retained differently, indicating pathway-specific regulation. We further find that PIKfyve recruitment and activity are separable and that PIKfyve activation stimulates its own dissociation. SnxA is therefore a new tool for reporting PI(3,5)P2 in live cells that reveals key mechanistic details of the role and regulation of PIKfyve/PI(3,5)P2.
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Affiliation(s)
- James H. Vines
- School of Biosciences, University of Sheffield, Firth Court Western Bank, Sheffield, UK
| | - Hannes Maib
- Division of Molecular, Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Catherine M. Buckley
- School of Biosciences, University of Sheffield, Firth Court Western Bank, Sheffield, UK
| | - Aurelie Gueho
- Department of Biochemistry, Faculty of Science, University of Geneva, Geneva, Switzerland
| | - Zhou Zhu
- School of Biosciences, University of Sheffield, Firth Court Western Bank, Sheffield, UK
| | - Thierry Soldati
- Department of Biochemistry, Faculty of Science, University of Geneva, Geneva, Switzerland
| | - David H. Murray
- Division of Molecular, Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Jason S. King
- School of Biosciences, University of Sheffield, Firth Court Western Bank, Sheffield, UK
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5
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Budziaszek J, Pilarczyk-Zurek M, Dobosz E, Kozinska A, Nowicki D, Obszanska K, Szalewska-Pałasz A, Kern-Zdanowicz I, Sitkiewicz I, Koziel J. Studies of Streptococcus anginosus Virulence in Dictyostelium discoideum and Galleria mellonella Models. Infect Immun 2023; 91:e0001623. [PMID: 37097148 DOI: 10.1128/iai.00016-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023] Open
Abstract
For many years, Streptococcus anginosus has been considered a commensal colonizing the oral cavity, as well as the gastrointestinal and genitourinary tracts. However, recent epidemiological and clinical data designate this bacterium as an emerging opportunistic pathogen. Despite the reported pathogenicity of S. anginosus, the molecular mechanism underpinning its virulence is poorly described. Therefore, our goal was to develop and optimize efficient and simple infection models that can be applied to examine the virulence of S. anginosus and to study host-pathogen interactions. Using 23 S. anginosus isolates collected from different infections, including severe and superficial infections, as well as an attenuated strain devoid of CppA, we demonstrate for the first time that Dictyostelium discoideum is a suitable model for initial, fast, and large-scale screening of virulence. Furthermore, we found that another nonvertebrate animal model, Galleria mellonella, can be used to study the pathogenesis of S. anginosus infection, with an emphasis on the interactions between the pathogen and host innate immunity. Examining the profile of immune defense genes, including antimicrobial peptides, opsonins, regulators of nodulation, and inhibitors of proteases, by quantitative PCR (qPCR) we identified different immune response profiles depending on the S. anginosus strain. Using these models, we show that S. anginosus is resistant to the bactericidal activity of phagocytes, a phenomenon confirmed using human neutrophils. Notably, since we found that the data from these models corresponded to the clinical severity of infection, we propose their further application to studies of the virulence of S. anginosus.
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Affiliation(s)
- Joanna Budziaszek
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Magdalena Pilarczyk-Zurek
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Ewelina Dobosz
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Aleksandra Kozinska
- Department of Drug Biotechnology and Bioinformatics, National Medicines Institute, Warsaw, Poland
| | - Dariusz Nowicki
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
- Department of Molecular Biology, University of Gdańsk, Gdańsk, Poland
| | - Katarzyna Obszanska
- Department of Drug Biotechnology and Bioinformatics, National Medicines Institute, Warsaw, Poland
| | | | | | - Izabela Sitkiewicz
- Institute of Biology, Warsaw University of Life Sciences-SGGW, Warsaw, Poland
| | - Joanna Koziel
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
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6
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Associational Resistance to Predation by Protists in a Mixed Species Biofilm. Appl Environ Microbiol 2023; 89:e0174122. [PMID: 36656007 PMCID: PMC9972941 DOI: 10.1128/aem.01741-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Mixed species biofilms exhibit increased tolerance to numerous stresses compared to single species biofilms. The aim of this study was to examine the effect of grazing by the heterotrophic protist, Tetrahymena pyriformis, on a mixed species biofilm consisting of Pseudomonas aeruginosa, Pseudomonas protegens, and Klebsiella pneumoniae. Protozoan grazing significantly reduced the single species K. pneumoniae biofilm, and the single species P. protegens biofilm was also sensitive to grazing. In contrast, P. aeruginosa biofilms were resistant to predation. This resistance protected the otherwise sensitive members of the mixed species biofilm consortium. Rhamnolipids produced by P. aeruginosa were shown to be the primary toxic factor for T. pyriformis. However, a rhamnolipid-deficient mutant of P. aeruginosa (P. aeruginosa ΔrhlAB) maintained grazing resistance in the biofilm, suggesting the presence of at least one additional protective mechanism. P. aeruginosa with a deleted gene encoding the type III secretion system also resisted grazing. A transposon library was generated in the ΔrhlAB mutant to identify the additional factor involved in community biofilm protection. Results indicated that the Pseudomonas Quinolone Signal (PQS), a quorum sensing signaling molecule, was likely responsible for this effect. We confirmed this observation by showing that double mutants of ΔrhlAB and genes in the PQS biosynthetic operon lost grazing protection. We also showed that PQS was directly toxic to T. pyriformis. This study demonstrates that residing in a mixed species biofilm can be an advantageous strategy for grazing sensitive bacterial species, as P. aeruginosa confers community protection from protozoan grazing through multiple mechanisms. IMPORTANCE Biofilms have been shown to protect bacterial cells from predation by protists. Biofilm studies have traditionally used single species systems, which have provided information on the mechanisms and regulation of biofilm formation and dispersal, and the effects of predation on these biofilms. However, biofilms in nature are comprised of multiple species. To better understand how multispecies biofilms are impacted by predation, a model mixed-species biofilm was here exposed to protozoan predation. We show that the grazing sensitive strains K. pneumonia and P. protogens gained associational resistance from the grazing resistant P. aeruginosa. Resistance was due to the secretion of rhamnolipids and quorum sensing molecule PQS. This work highlights the importance of using mixed species systems.
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7
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Mansor MR, AL-Khalidi ZS, Almuhanna EH, Hussein HR, Almulla AF, Alnaji HA. Detection and Study nan1 and tox A genes of Pseudomonas aeruginosa in Isolates from Otitis Media Patients Considered as Virulence Factors. IRANIAN JOURNAL OF MEDICAL MICROBIOLOGY 2023. [DOI: 10.30699/ijmm.17.1.81] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
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8
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Ifrid E, Ouertatani-Sakouhi H, Jauslin T, Kicka S, Chiriano G, Harrison CF, Hilbi H, Scapozza L, Soldati T, Cosson P. 5-ethyl-2'-deoxyuridine fragilizes Klebsiella pneumoniae outer wall and facilitates intracellular killing by phagocytic cells. PLoS One 2022; 17:e0269093. [PMID: 36315510 PMCID: PMC9621411 DOI: 10.1371/journal.pone.0269093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 05/14/2022] [Indexed: 01/24/2023] Open
Abstract
Klebsiella pneumoniae is the causative agent of a variety of severe infections. Many K. pneumoniae strains are resistant to multiple antibiotics, and this situation creates a need for new antibacterial molecules. K. pneumoniae pathogenicity relies largely on its ability to escape phagocytosis and intracellular killing by phagocytic cells. Interfering with these escape mechanisms may allow to decrease bacterial virulence and to combat infections. In this study, we used Dictyostelium discoideum as a model phagocyte to screen a collection of 1,099 chemical compounds. Phg1A KO D. discoideum cells cannot feed upon K. pneumoniae bacteria, unless bacteria bear mutations decreasing their virulence. We identified 3 non-antibiotic compounds that restored growth of phg1A KO cells on K. pneumoniae, and we characterized the mode of action of one of them, 5-ethyl-2'-deoxyuridine (K2). K2-treated bacteria were more rapidly killed in D. discoideum phagosomes than non-treated bacteria. They were more sensitive to polymyxin and their outer membrane was more accessible to a hydrophobic fluorescent probe. These results suggest that K2 acts by rendering the membrane of K. pneumoniae accessible to antibacterial effectors. K2 was effective on three different K. pneumoniae strains, and acted at concentrations as low as 3 μM. K2 has previously been used to treat viral infections but its precise molecular mechanism of action in K. pneumoniae remains to be determined.
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Affiliation(s)
- Estelle Ifrid
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Centre Médical Universitaire, Geneva, Switzerland
| | - Hajer Ouertatani-Sakouhi
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Centre Médical Universitaire, Geneva, Switzerland
| | - Tania Jauslin
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Centre Médical Universitaire, Geneva, Switzerland
| | - Sebastien Kicka
- Department of Biochemistry, Faculty of Science, University of Geneva, Geneva, Switzerland
| | - Gianpaolo Chiriano
- Pharmaceutical Biochemistry, School of Pharmaceutical Sciences, University of Geneva, Geneva, Switzerland
| | - Christopher F. Harrison
- Max von Pettenkofer Institute, Department of Medicine, Ludwig-Maximilians University Munich, Munich, Germany
| | - Hubert Hilbi
- Institute of Medical Microbiology, Department of Medicine, University of Zürich, Zürich, Switzerland
| | - Leonardo Scapozza
- Pharmaceutical Biochemistry, School of Pharmaceutical Sciences, University of Geneva, Geneva, Switzerland
| | - Thierry Soldati
- Department of Biochemistry, Faculty of Science, University of Geneva, Geneva, Switzerland
| | - Pierre Cosson
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Centre Médical Universitaire, Geneva, Switzerland
- * E-mail:
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9
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Gdaniec BG, Bonini F, Prodon F, Braschler T, Köhler T, van Delden C. Pseudomonas aeruginosa rhamnolipid micelles deliver toxic metabolites and antibiotics into Staphylococcus aureus. iScience 2022; 25:103669. [PMID: 35028539 PMCID: PMC8741607 DOI: 10.1016/j.isci.2021.103669] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 11/05/2021] [Accepted: 12/17/2021] [Indexed: 02/07/2023] Open
Abstract
Efficient delivery of toxic compounds to bacterial competitors is essential during interspecies microbial warfare. Rhamnolipids (RLPs) are glycolipids produced by Pseudomonas and Burkholderia species involved in solubilization and uptake of environmental aliphatic hydrocarbons and perform as biosurfactants for swarming motility. Here, we show that RLPs produced by Pseudomonas aeruginosa associate to form micelles. Using high-resolution microscopy, we found that RLP micelles serve as carriers for self-produced toxic compounds, which they deliver to Staphylococcus aureus cells, thereby enhancing and accelerating S. aureus killing. RLPs also potentiated the activity of lincosamide antibiotics, suggesting that RLP micelles may transport not only self-produced but also heterologous compounds to target competing bacterial species Pseudomonas aeruginosa rhamnolipids form micelles Rhamnolipid micelles delivery pyochelin into S. aureus cells Rhamnolipid micelles potentiate activity of lincosamide antibiotics against S. aureus
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Affiliation(s)
- Bartosz Gerard Gdaniec
- Transplant Infectious Diseases Unit, University Hospitals Geneva, Rue Gabrielle-Perret-Gentil 4, 1205 Geneva, Switzerland.,Department of Microbiology and Molecular Medicine, University of Geneva, 1, Rue Michel Servet, 1211 Geneva, Switzerland.,Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, 1, Rue Michel Servet, 1211 Geneva, Switzerland
| | - Fabien Bonini
- Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, 1, Rue Michel Servet, 1211 Geneva, Switzerland
| | - François Prodon
- Bioimaging Core Facility, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland
| | - Thomas Braschler
- Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, 1, Rue Michel Servet, 1211 Geneva, Switzerland
| | - Thilo Köhler
- Transplant Infectious Diseases Unit, University Hospitals Geneva, Rue Gabrielle-Perret-Gentil 4, 1205 Geneva, Switzerland.,Department of Microbiology and Molecular Medicine, University of Geneva, 1, Rue Michel Servet, 1211 Geneva, Switzerland
| | - Christian van Delden
- Transplant Infectious Diseases Unit, University Hospitals Geneva, Rue Gabrielle-Perret-Gentil 4, 1205 Geneva, Switzerland.,Department of Microbiology and Molecular Medicine, University of Geneva, 1, Rue Michel Servet, 1211 Geneva, Switzerland
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10
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The genetic architecture underlying prey-dependent performance in a microbial predator. Nat Commun 2022; 13:319. [PMID: 35031602 PMCID: PMC8760311 DOI: 10.1038/s41467-021-27844-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 12/10/2021] [Indexed: 11/30/2022] Open
Abstract
Natural selection should favour generalist predators that outperform specialists across all prey types. Two genetic solutions could explain why intraspecific variation in predatory performance is, nonetheless, widespread: mutations beneficial on one prey type are costly on another (antagonistic pleiotropy), or mutational effects are prey-specific, which weakens selection, allowing variation to persist (relaxed selection). To understand the relative importance of these alternatives, we characterised natural variation in predatory performance in the microbial predator Dictyostelium discoideum. We found widespread nontransitive differences among strains in predatory success across different bacterial prey, which can facilitate stain coexistence in multi-prey environments. To understand the genetic basis, we developed methods for high throughput experimental evolution on different prey (REMI-seq). Most mutations (~77%) had prey-specific effects, with very few (~4%) showing antagonistic pleiotropy. This highlights the potential for prey-specific effects to dilute selection, which would inhibit the purging of variation and prevent the emergence of an optimal generalist predator. What prevents a generalist predator from evolving and outperforming specialist predators? By combing analyses of natural variation with experimental evolution, Stewart et al. suggest that predator variation persists because most mutations have prey-specific effects, which results in relaxed selection
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11
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Adaptation to an amoeba host leads to Pseudomonas aeruginosa isolates with attenuated virulence. Appl Environ Microbiol 2022; 88:e0232221. [PMID: 35020451 PMCID: PMC8904051 DOI: 10.1128/aem.02322-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The opportunistic pathogen Pseudomonas aeruginosa is ubiquitous in the environment, and in humans, it is capable of causing acute or chronic infections. In the natural environment, predation by bacterivorous protozoa represents a primary threat to bacteria. Here, we determined the impact of long-term exposure of P. aeruginosa to predation pressure. P. aeruginosa persisted when coincubated with the bacterivorous Acanthamoeba castellanii for extended periods and produced genetic and phenotypic variants. Sequencing of late-stage amoeba-adapted P. aeruginosa isolates demonstrated single nucleotide polymorphisms within genes that encode known virulence factors, and this correlated with a reduction in expression of virulence traits. Virulence for the nematode Caenorhabditis elegans was attenuated in late-stage amoeba-adapted P. aeruginosa compared to early-stage amoeba-adapted and nonadapted counterparts. Further, late-stage amoeba-adapted P. aeruginosa showed increased competitive fitness and enhanced survival in amoebae as well as in macrophage and neutrophils. Interestingly, our findings indicate that the selection imposed by amoebae resulted in P. aeruginosa isolates with reduced virulence and enhanced fitness, similar to those recovered from chronic cystic fibrosis infections. Thus, predation by protozoa and long-term colonization of the human host may represent similar environments that select for similar losses of gene function. IMPORTANCEPseudomonas aeruginosa is an opportunistic pathogen that causes both acute infections in plants and animals, including humans, and chronic infections in immunocompromised and cystic fibrosis patients. This bacterium is commonly found in soils and water, where bacteria are constantly under threat of being consumed by bacterial predators, e.g., protozoa. To escape being killed, bacteria have evolved a suite of mechanisms that protect them from being consumed or digested. Here, we examined the effect of long-term predation on the genotypes and phenotypes expressed by P. aeruginosa. We show that long-term coincubation with protozoa gave rise to mutations that resulted in P. aeruginosa becoming less pathogenic. This is particularly interesting as similar mutations arise in bacteria associated with chronic infections. Importantly, the genetic and phenotypic traits possessed by late-stage amoeba-adapted P. aeruginosa are similar to those observed in isolates obtained from chronic cystic fibrosis infections. This notable overlap in adaptation to different host types suggests similar selection pressures among host cell types as well as similar adaptation strategies.
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12
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de Oliveira AL, Barbieri NL, Newman DM, Young MM, Nolan LK, Logue CM. Characterizing the Type 6 Secretion System (T6SS) and its role in the virulence of avian pathogenic Escherichia coli strain APECO18. PeerJ 2021; 9:e12631. [PMID: 35003930 PMCID: PMC8686734 DOI: 10.7717/peerj.12631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 11/22/2021] [Indexed: 11/22/2022] Open
Abstract
Avian pathogenic E. coli is the causative agent of extra-intestinal infections in birds known as colibacillosis, which can manifest as localized or systemic infections. The disease affects all stages of poultry production, resulting in economic losses that occur due to morbidity, carcass condemnation and increased mortality of the birds. APEC strains have a diverse virulence trait repertoire, which includes virulence factors involved in adherence to and invasion of the host cells, serum resistance factors, and toxins. However, the pathogenesis of APEC infections remains to be fully elucidated. The Type 6 secretion (T6SS) system has recently gained attention due to its role in the infection process and protection of bacteria from host defenses in human and animal pathogens. Previous work has shown that T6SS components are involved in the adherence to and invasion of host cells, as well as in the formation of biofilm, and intramacrophage bacterial replication. Here, we analyzed the frequency of T6SS genes hcp, impK, evpB, vasK and icmF in a collection of APEC strains and their potential role in virulence-associated phenotypes of APECO18. The T6SS genes were found to be significantly more prevalent in APEC than in fecal E. coli isolates from healthy birds. Expression of T6SS genes was analyzed in culture media and upon contact with host cells. Mutants were generated for hcp, impK, evpB, and icmF and characterized for their impact on virulence-associated phenotypes, including adherence to and invasion of host model cells, and resistance to predation by Dictyostelium discoideum. Deletion of the aforementioned genes did not significantly affect adherence and invasion capabilities of APECO18. Deletion of hcp reduced resistance of APECO18 to predation by D. discoideum, suggesting that T6SS is involved in the virulence of APECO18.
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Affiliation(s)
- Aline L. de Oliveira
- Department of Population Health, University of Georgia, Athens, GA, United States of America
- Department of Microbiology, University of Georgia, Athens, GA, United States of America
| | - Nicolle L. Barbieri
- Department of Population Health, University of Georgia, Athens, GA, United States of America
| | - Darby M. Newman
- Department of Population Health, University of Georgia, Athens, GA, United States of America
| | - Meaghan M. Young
- Department of Population Health, University of Georgia, Athens, GA, United States of America
| | - Lisa K. Nolan
- Department of Infectious Diseases, University of Georgia, Athens, GA, United States of America
| | - Catherine M. Logue
- Department of Population Health, University of Georgia, Athens, GA, United States of America
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Pseudomonas aeruginosa mexR and mexEF Antibiotic Efflux Pump Variants Exhibit Increased Virulence. Antibiotics (Basel) 2021; 10:antibiotics10101164. [PMID: 34680745 PMCID: PMC8532662 DOI: 10.3390/antibiotics10101164] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/21/2021] [Accepted: 09/24/2021] [Indexed: 11/18/2022] Open
Abstract
Antibiotic-resistant Pseudomonas aeruginosa infections are the primary cause of mortality in people with cystic fibrosis (CF). Yet, it has only recently become appreciated that resistance mutations can also increase P. aeruginosa virulence, even in the absence of antibiotics. Moreover, the mechanisms by which resistance mutations increase virulence are poorly understood. In this study we tested the hypothesis that mutations affecting efflux pumps can directly increase P. aeruginosa virulence. Using genetics, physiological assays, and model infections, we show that efflux pump mutations can increase virulence. Mutations of the mexEF efflux pump system increased swarming, rhamnolipid production, and lethality in a mouse infection model, while mutations in mexR that increased expression of the mexAB-oprM efflux system increased virulence during an acute murine lung infection without affecting swarming or rhamnolipid gene expression. Finally, we show that an efflux pump inhibitor, which represents a proposed novel treatment approach for P. aeruginosa, increased rhamnolipid gene expression in a dose-dependent manner. This finding is important because rhamnolipids are key virulence factors involved in dissemination through epithelial barriers and cause neutrophil necrosis. Together, these data show how current and proposed future anti-Pseudomonal treatments may unintentionally make infections worse by increasing virulence. Therefore, treatments that target efflux should be pursued with caution.
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Amoebae as Targets for Toxins or Effectors Secreted by Mammalian Pathogens. Toxins (Basel) 2021; 13:toxins13080526. [PMID: 34437397 PMCID: PMC8402458 DOI: 10.3390/toxins13080526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 07/26/2021] [Accepted: 07/26/2021] [Indexed: 11/28/2022] Open
Abstract
Numerous microorganisms, pathogenic for mammals, come from the environment where they encounter predators such as free-living amoebae (FLA). The selective pressure due to this interaction could have generated virulence traits that are deleterious for amoebae and represents a weapon against mammals. Toxins are one of these powerful tools that are essential for bacteria or fungi to survive. Which amoebae are used as a model to study the effects of toxins? What amoeba functions have been reported to be disrupted by toxins and bacterial secreted factors? Do bacteria and fungi effectors affect eukaryotic cells similarly? Here, we review some studies allowing to answer these questions, highlighting the necessity to extend investigations of microbial pathogenicity, from mammals to the environmental reservoir that are amoebae.
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15
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Martín‐González J, Montero‐Bullón J, Lacal J. Dictyostelium discoideum as a non-mammalian biomedical model. Microb Biotechnol 2021; 14:111-125. [PMID: 33124755 PMCID: PMC7888446 DOI: 10.1111/1751-7915.13692] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 10/06/2020] [Accepted: 10/11/2020] [Indexed: 02/06/2023] Open
Abstract
Dictyostelium discoideum is one of eight non-mammalian model organisms recognized by the National Institute of Health for the study of human pathology. The use of this slime mould is possible owing to similarities in cell structure, behaviour and intracellular signalling with mammalian cells. Its haploid set of chromosomes completely sequenced amenable to genetic manipulation, its unique and short life cycle with unicellular and multicellular stages, and phenotypic richness encoding many human orthologues, make Dictyostelium a representative and simple model organism to unveil cellular processes in human disease. Dictyostelium studies within the biomedical field have provided fundamental knowledge in the areas of bacterial infection, immune cell chemotaxis, autophagy/phagocytosis and mitochondrial and neurological disorders. Consequently, Dictyostelium has been used to the development of related pharmacological treatments. Herein, we review the utilization of Dictyostelium as a model organism in biomedicine.
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Affiliation(s)
- Javier Martín‐González
- Molecular Genetics of Human Diseases GroupDepartment of Microbiology and GeneticsFaculty of BiologyUniversity of SalamancaCampus Miguel de UnamunoSalamancaE‐37007Spain
| | - Javier‐Fernando Montero‐Bullón
- Metabolic Engineering GroupDepartment of Microbiology and GeneticsUniversity of SalamancaCampus Miguel de UnamunoSalamancaE‐37007Spain
| | - Jesus Lacal
- Molecular Genetics of Human Diseases GroupDepartment of Microbiology and GeneticsFaculty of BiologyUniversity of SalamancaCampus Miguel de UnamunoSalamancaE‐37007Spain
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16
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Herzog M, Tiso T, Blank LM, Winter R. Interaction of rhamnolipids with model biomembranes of varying complexity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183431. [DOI: 10.1016/j.bbamem.2020.183431] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 07/26/2020] [Indexed: 12/25/2022]
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17
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Gdaniec BG, Allard PM, Queiroz EF, Wolfender JL, van Delden C, Köhler T. Surface sensing triggers a broad-spectrum antimicrobial response in Pseudomonas aeruginosa. Environ Microbiol 2020; 22:3572-3587. [PMID: 32573899 PMCID: PMC7496599 DOI: 10.1111/1462-2920.15139] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 06/15/2020] [Accepted: 06/21/2020] [Indexed: 12/14/2022]
Abstract
Interspecies bacterial competition may occur via cell‐associated or secreted determinants and is key to successful niche colonization. We previously evolved Pseudomonas aeruginosa in the presence of Staphylococcus aureus and identified mutations in the Wsp surface‐sensing signalling system. Surprisingly, a ΔwspF mutant, characterized by increased c‐di‐GMP levels and biofilm formation capacity, showed potent killing activity towards S. aureus in its culture supernatant. Here, we used an unbiased metabolomic analysis of culture supernatants to identify rhamnolipids, alkyl quinoline N‐oxides and two siderophores as members of four chemical clusters, which were more abundant in the ΔwspF mutant supernatants. Killing activities were quorum‐sensing controlled but independent of c‐di‐GMP levels. Based on the metabolomic analysis, we formulated a synthetic cocktail of four compounds, showing broad‐spectrum anti‐bacterial killing, including both Gram‐positive and Gram‐negative bacteria. The combination of quorum‐sensing‐controlled killing and Wsp‐system mediated biofilm formation endows P. aeruginosa with capacities essential for niche establishment and host colonization.
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Affiliation(s)
- Bartosz Gerard Gdaniec
- Transplant Infectious Diseases Unit, University Hospital Geneva, Geneva, Switzerland.,Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Pierre-Marie Allard
- School of Pharmaceutical Sciences, EPGL, University of Geneva, University of Lausanne, Geneva, Switzerland
| | - Emerson Ferreira Queiroz
- School of Pharmaceutical Sciences, EPGL, University of Geneva, University of Lausanne, Geneva, Switzerland
| | - Jean-Luc Wolfender
- School of Pharmaceutical Sciences, EPGL, University of Geneva, University of Lausanne, Geneva, Switzerland
| | - Christian van Delden
- Transplant Infectious Diseases Unit, University Hospital Geneva, Geneva, Switzerland.,Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Thilo Köhler
- Transplant Infectious Diseases Unit, University Hospital Geneva, Geneva, Switzerland.,Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
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18
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Sajid M, Ahmad Khan MS, Singh Cameotra S, Safar Al-Thubiani A. Biosurfactants: Potential applications as immunomodulator drugs. Immunol Lett 2020; 223:71-77. [DOI: 10.1016/j.imlet.2020.04.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 03/24/2020] [Accepted: 04/04/2020] [Indexed: 10/24/2022]
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Paraburkholderia Symbionts Display Variable Infection Patterns That Are Not Predictive of Amoeba Host Outcomes. Genes (Basel) 2020; 11:genes11060674. [PMID: 32575747 PMCID: PMC7349545 DOI: 10.3390/genes11060674] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/07/2020] [Accepted: 06/18/2020] [Indexed: 12/17/2022] Open
Abstract
Symbiotic interactions exist within a parasitism to mutualism continuum that is influenced, among others, by genes and context. Dynamics of intracellular invasion, replication, and prevalence may underscore both host survivability and symbiont stability. More infectious symbionts might exert higher corresponding costs to hosts, which could ultimately disadvantage both partners. Here, we quantify infection patterns of diverse Paraburkholderia symbiont genotypes in their amoeba host Dictyostelium discoideum and probe the relationship between these patterns and host outcomes. We exposed D. discoideum to thirteen strains of Paraburkholderia each belonging to one of the three symbiont species found to naturally infect D. discoideum: Paraburkholderia agricolaris, Paraburkholderia hayleyella, and Paraburkholderia bonniea. We quantified the infection prevalence and intracellular density of fluorescently labeled symbionts along with the final host population size using flow cytometry and confocal microscopy. We find that infection phenotypes vary across symbiont strains. Symbionts belonging to the same species generally display similar infection patterns but are interestingly distinct when it comes to host outcomes. This results in final infection loads that do not strongly correlate to final host outcomes, suggesting other genetic factors that are not a direct cause or consequence of symbiont abundance impact host fitness.
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20
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Lamrabet O, Melotti A, Burdet F, Hanna N, Perrin J, Nitschke J, Pagni M, Hilbi H, Soldati T, Cosson P. Transcriptional Responses of Dictyostelium discoideum Exposed to Different Classes of Bacteria. Front Microbiol 2020; 11:410. [PMID: 32210949 PMCID: PMC7078664 DOI: 10.3389/fmicb.2020.00410] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 02/27/2020] [Indexed: 12/19/2022] Open
Abstract
Dictyostelium discoideum amoebae feed by ingesting bacteria, then killing them in phagosomes. Ingestion and killing of different bacteria have been shown to rely on largely different molecular mechanisms. One would thus expect that D. discoideum adapts its ingestion and killing machinery when encountering different bacteria. In this study, we investigated by RNA sequencing if and how D. discoideum amoebae respond to the presence of different bacteria by modifying their gene expression patterns. Each bacterial species analyzed induced a specific modification of the transcriptome. Bacteria such as Bacillus subtilis, Klebsiella pneumoniae, or Mycobacterium marinum induced a specific and different transcriptional response, while Micrococcus luteus did not trigger a significant gene regulation. Although folate has been proposed to be one of the key molecules secreted by bacteria and recognized by hunting amoebae, it elicited a very specific and restricted transcriptional signature, distinct from that triggered by any bacteria analyzed here. Our results indicate that D. discoideum amoebae respond in a highly specific, almost non-overlapping manner to different species of bacteria. We additionally identify specific sets of genes that can be used as reporters of the response of D. discoideum to different bacteria.
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Affiliation(s)
- Otmane Lamrabet
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Astrid Melotti
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Frédéric Burdet
- Vital-IT Group, SIB, Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Nabil Hanna
- Department of Biochemistry, Faculty of Science, University of Geneva, Geneva, Switzerland
| | - Jackie Perrin
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Jahn Nitschke
- Department of Biochemistry, Faculty of Science, University of Geneva, Geneva, Switzerland
| | - Marco Pagni
- Vital-IT Group, SIB, Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Hubert Hilbi
- Faculty of Medicine, Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Thierry Soldati
- Department of Biochemistry, Faculty of Science, University of Geneva, Geneva, Switzerland
| | - Pierre Cosson
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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21
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Optimisation of External Factors for the Growth of Francisella novicida within Dictyostelium discoideum. BIOMED RESEARCH INTERNATIONAL 2020; 2020:6826983. [PMID: 32090107 PMCID: PMC6996686 DOI: 10.1155/2020/6826983] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 01/04/2020] [Indexed: 02/06/2023]
Abstract
The amoeba Dictyostelium discoideum has been used as a model organism to study host-pathogen interaction in many intracellular bacteria. Francisella tularensis is a Gram-negative, highly infectious bacterium that causes the zoonotic disease tularemia. The bacterium is able to replicate in different phagocytic and nonphagocytic cells including mammalian, amoebae, and arthropod cells. The aim of this study was to determine the optimal temperature and infection dose in the interaction of Francisella novicida with D. discoideum in order to establish a model of Francisella infection in the social amoeba. The amoeba cells were infected with a different multiplicity of infection (5, 10, and 100) and incubated at different temperatures (22, 25, 27, 30, and 37°C). The number of intracellular bacteria within D. discoideum, as well as cytotoxicity, was determined at 2, 4, 24, 48, and 72 hours after infection. Our results showed that the optimal temperature for Francisella intracellular replication within amoeba is 30°C with the MOI of 10. We can conclude that this MOI and temperature induced the optimal growth of bacteria in Dictyostelium with low cytotoxicity.
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22
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A predation assay using amoebae to screen for virulence factors unearthed the first W. chondrophila inclusion membrane protein. Sci Rep 2019; 9:19485. [PMID: 31862969 PMCID: PMC6925127 DOI: 10.1038/s41598-019-55511-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 11/11/2019] [Indexed: 01/21/2023] Open
Abstract
Waddlia chondrophila is an intracellular bacterium phylogenetically related to the well-studied human and animal pathogens of the Chlamydiaceae family. In the last decade, W. chondrophila was convincingly demonstrated to be associated with adverse pregnancy outcomes in humans and abortions in animals. All members of the phylum Chlamydiae possess a Type Three Secretion System that they use for delivering virulence proteins into the host cell cytosol to modulate their environment and create optimal conditions to complete their life cycle. To identify W. chondrophila virulence proteins, we used an original screening approach that combines a cosmid library with an assay monitoring resistance to predation by phagocytic amoebae. This technique combined with bioinformatic data allowed the identification of 28 candidate virulence proteins, including Wimp1, the first identified inclusion membrane protein of W. chondrophila.
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Bodinier R, Leiba J, Sabra A, Jauslin TN, Lamrabet O, Guilhen C, Marchetti A, Iwade Y, Kawata T, Lima WC, Cosson P. LrrkA, a kinase with leucine-rich repeats, links folate sensing with Kil2 activity and intracellular killing. Cell Microbiol 2019; 22:e13129. [PMID: 31652367 PMCID: PMC7003747 DOI: 10.1111/cmi.13129] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 09/20/2019] [Accepted: 10/03/2019] [Indexed: 12/14/2022]
Abstract
Phagocytic cells ingest bacteria by phagocytosis and kill them efficiently inside phagolysosomes. The molecular mechanisms involved in intracellular killing and their regulation are complex and still incompletely understood. Dictyostelium discoideum has been used as a model to discover and to study new gene products involved in intracellular killing of ingested bacteria. In this study, we performed random mutagenesis of Dictyostelium cells and isolated a mutant defective for growth on bacteria. This mutant is characterized by the genetic inactivation of the lrrkA gene, which encodes a protein with a kinase domain and leucine-rich repeats. LrrkA knockout (KO) cells kill ingested Klebsiella pneumoniae bacteria inefficiently. This defect is not additive to the killing defect observed in kil2 KO cells, suggesting that the function of Kil2 is partially controlled by LrrkA. Indeed, lrrkA KO cells exhibit a phenotype similar to that of kil2 KO cells: Intraphagosomal proteolysis is inefficient, and both intraphagosomal killing and proteolysis are restored upon exogenous supplementation with magnesium ions. Bacterially secreted folate stimulates intracellular killing in Dictyostelium cells, but this stimulation is lost in cells with genetic inactivation of kil2, lrrkA, or far1. Together, these results indicate that the stimulation of intracellular killing by folate involves Far1 (the cell surface receptor for folate), LrrkA, and Kil2. This study is the first identification of a signalling pathway regulating intraphagosomal bacterial killing in Dictyostelium cells.
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Affiliation(s)
- Romain Bodinier
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Jade Leiba
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Ayman Sabra
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Tania N Jauslin
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Otmane Lamrabet
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Cyril Guilhen
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Anna Marchetti
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Yumi Iwade
- Department of Biology, Faculty of Science, Toho University, Funabashi, Japan
| | - Takefumi Kawata
- Department of Biology, Faculty of Science, Toho University, Funabashi, Japan
| | - Wanessa C Lima
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Pierre Cosson
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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24
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Dai L, Wu TQ, Xiong YS, Ni HB, Ding Y, Zhang WC, Chu SP, Ju SQ, Yu J. Ibuprofen-mediated potential inhibition of biofilm development and quorum sensing in Pseudomonas aeruginosa. Life Sci 2019; 237:116947. [PMID: 31605708 DOI: 10.1016/j.lfs.2019.116947] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 09/28/2019] [Accepted: 10/08/2019] [Indexed: 01/01/2023]
Abstract
AIMS Pseudomonas aeruginosa is one of the leading causes of opportunistic and hospital-acquired infections worldwide, which is frequently linked with clinical treatment difficulties. Ibuprofen, a widely used non-steroidal anti-inflammatory drug, has been previously reported to exert antimicrobial activity with the specific mechanism. We hypothesized that inhibition of P. aeruginosa with ibuprofen is involved in the quorum sensing (QS) systems. MAIN METHODS CFU was utilized to assessed the growth condition of P. aeruginosa. Crystal violent staining and acridine orange staining was used to evaluate the biofilm formation and adherence activity. The detection of QS virulence factors such as pyocyanin, elastase, protease, and rhamnolipids were applied to investigation the anti-QS activity of ibuprofen against P. aeruginosa. The production of 3-oxo-C12-HSL and C4-HSL was confirmed by liquid chromatography/mass spectrometry analysis. qRT-PCR was used to identify the QS-related gene expression. Furthermore, we explored the binding effects between ibuprofen and QS-associated proteins with molecular docking. KEY FINDINGS Ibuprofen inhibits P. aeruginosa biofilm formation and adherence activity. And the inhibitory effects of ibuprofen on C4-HSL levels were concentration-dependent (p < 0.05), while it has no effect on 3-oxo-C12-HSL. Moreover, ibuprofen attenuates the production of virulence factors in P. aeruginosa (p < 0.05). In addition, the genes of QS system were decreased after the ibuprofen treatment (p < 0.05). Of note, ibuprofen was binding with LuxR, LasR, LasI, and RhlR at high binding scores. SIGNIFICANCE The antibiofilm and anti-QS activity of ibuprofen suggest that it can be a candidate drug for the treatment of clinical infections with P. aeruginosa.
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Affiliation(s)
- Lu Dai
- Department of Laboratory Medicine, Affiliated Hospital of Nantong University, 20 Xi Si Road, Nantong, 226001, PR China; Department of Laboratory Medicine, Kunshan affiliated Hospital of Nanjing University of Chinese Medicine, 189 Chao Yang Road, Kunshan, 215300, PR China
| | - Tian-Qi Wu
- Glenelg Country School, 12793 Folly Quarter Rd, Ellicott City, MD, 21042, USA
| | - Yi-Song Xiong
- Department of Laboratory Medicine, Chengdu Military General Hospital, 270 Tian Hui Road, Chengdu, 610000, PR China
| | - Hong-Bing Ni
- Department of Business and External Cooperation, Affiliated Hospital of Nantong University, 20 Xi Si Road, Nantong, 226001, PR China
| | - Ye Ding
- Department of Laboratory Medicine, Affiliated Hospital of Nantong University, 20 Xi Si Road, Nantong, 226001, PR China
| | - Wen-Chen Zhang
- Department of Clinical Laboratory, Wuxi Children's Hospita, No. 299 at Qingyang Road, Wuxi, 214023, PR China
| | - Shao-Peng Chu
- Department of Laboratory Medicine, Affiliated Hospital of Nantong University, 20 Xi Si Road, Nantong, 226001, PR China
| | - Shao-Qing Ju
- Department of Laboratory Medicine, Affiliated Hospital of Nantong University, 20 Xi Si Road, Nantong, 226001, PR China
| | - Juan Yu
- Department of Laboratory Medicine, Affiliated Hospital of Nantong University, 20 Xi Si Road, Nantong, 226001, PR China; Insitute of Public Health, Nantong University, 9 Se Yuan Road, Nantong, 226001, PR China.
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Sadeq Al-Namil D, Patra D. Green solid-state based curcumin mediated rhamnolipids stabilized silver nanoparticles: Interaction of silver nanoparticles with cystine and albumins towards fluorescence sensing. Colloids Surf B Biointerfaces 2019; 173:647-653. [DOI: 10.1016/j.colsurfb.2018.10.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 09/26/2018] [Accepted: 10/13/2018] [Indexed: 12/11/2022]
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Abstract
Inspection of the genomes of bacterial pathogens indicates that their pathogenic potential relies, at least in part, on the activity of different elements that have been acquired by horizontal gene transfer from other (usually unknown) microorganisms. Similarly, in the case of resistance to antibiotics, besides mutation-driven resistance, the incorporation of novel resistance genes is a widespread evolutionary procedure for the acquisition of this phenotype. Current information in the field supports the idea that most (if not all) genes acquired by horizontal gene transfer by bacterial pathogens and contributing to their virulence potential or to antibiotic resistance originate in environmental, not human-pathogenic, microorganisms. Herein I discuss the potential functions that the genes that are dubbed virulence or antibiotic resistance genes may have in their original hosts in nonclinical, natural ecosystems. In addition, I discuss the potential bottlenecks modulating the transfer of virulence and antibiotic resistance determinants and the consequences in terms of speciation of acquiring one or another of both categories of genes. Finally, I propose that exaptation, a process by which a change of function is achieved by a change of habitat and not by changes in the element with the new functionality, is the basis of the evolution of virulence determinants and of antibiotic resistance genes.
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27
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Perinbam K, Siryaporn A. A Rapid Image-based Bacterial Virulence Assay Using Amoeba. J Vis Exp 2018. [PMID: 30010653 DOI: 10.3791/57844] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Traditional bacterial virulence assays involve prolonged exposure of bacteria over the course of several hours to host cells. During this time, bacteria can undergo changes in the physiology due to the exposure to host growth environment and the presence of the host cells. We developed an assay to rapidly measure the virulence state of bacteria that minimize the extent to which bacteria grow in the presence of host cells. Bacteria and amoebae are mixed together and immobilized on a single imaging plane using an agar pad. The procedure uses single-cell fluorescence imaging with calcein-acetoxymethyl ester (calcein-AM) as an indicator of host cell health. The fluorescence of host cells is analyzed after 1 h of exposure of host cells to bacteria using epifluorescence microscopy. Image analysis software is used to compute a host killing index. This method has been used to measure virulence within planktonic and surface-attached Pseudomonas aeruginosa sub-populations during the initial stage of biofilm formation and may be adapted to other bacteria and other stages of biofilm growth. This protocol provides a rapid and robust method of measuring virulence and avoids many of the complexities associated with the growth and maintenance of mammalian cell lines. Virulence phenotypes measured here using amoebae have also been validated using mouse macrophages. In particular, this assay was used to establish that surface attachment upregulates virulence in P. aeruginosa.
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Affiliation(s)
- Kumar Perinbam
- Department of Physics and Astronomy, University of California
| | - Albert Siryaporn
- Department of Physics and Astronomy, University of California; Department of Molecular Biology and Biochemistry, University of California;
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Mion S, Rémy B, Plener L, Chabrière E, Daudé D. [Prevent bacteria from communicating: Divide to cure]. ANNALES PHARMACEUTIQUES FRANÇAISES 2018; 76:249-264. [PMID: 29598881 DOI: 10.1016/j.pharma.2018.02.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 02/14/2018] [Accepted: 02/16/2018] [Indexed: 02/07/2023]
Abstract
Quorum Sensing (QS) is a communication system used by numerous bacteria to synchronize their behavior according to the cell density. In this way, bacteria secrete and sense small mediating molecules, called autoinducers (AI), which concentration increases in the environment proportionally to bacterial cell number. QS induces major physiological and phenotypic changes such as virulence induction and biofilm formation. Biofilm represents a physical barrier which shelters bacteria poorly sensitive to antimicrobial treatments and favors the apparition of resistance mechanisms. Disturbing QS is referred to as quorum quenching (QQ). This strategy is used by microorganisms themselves to prevent the development of specific group behaviors. Two strategies are mainly employed: the use of quorum sensing inhibitors (QSI) and of quorum quenching enzymes (QQE) that degrades AI. Many studies have been dedicated to identifying QSI (natural or synthetic) as well as QQE and demonstrating their anti-virulence and anti-biofilm effects on numerous bacterial species. Synergistic effects between QQ and traditional treatments such as antibiotherapy or with reemerging phage therapy have been put forward. The efficiency of numerous QSI and QQE was thereby demonstrated either with in vitro or in vivo animal models leading to the development of medical devices containing QSI and QQE to improve already existing treatments.
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Affiliation(s)
- S Mion
- Aix-Marseille Université, IRD, APHM, MEPHI, IHU-Méditerranée Infection, 19-21, boulevard Jean-Moulin, 13005 Marseille, France
| | - B Rémy
- Aix-Marseille Université, IRD, APHM, MEPHI, IHU-Méditerranée Infection, 19-21, boulevard Jean-Moulin, 13005 Marseille, France; Gene&GreenTK, 19-21, boulevard Jean-Moulin, 13005 Marseille, France
| | - L Plener
- Gene&GreenTK, 19-21, boulevard Jean-Moulin, 13005 Marseille, France
| | - E Chabrière
- Aix-Marseille Université, IRD, APHM, MEPHI, IHU-Méditerranée Infection, 19-21, boulevard Jean-Moulin, 13005 Marseille, France
| | - D Daudé
- Gene&GreenTK, 19-21, boulevard Jean-Moulin, 13005 Marseille, France.
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Dhakshinamoorthy R, Bitzhenner M, Cosson P, Soldati T, Leippe M. The Saposin-Like Protein AplD Displays Pore-Forming Activity and Participates in Defense Against Bacterial Infection During a Multicellular Stage of Dictyostelium discoideum. Front Cell Infect Microbiol 2018; 8:73. [PMID: 29662839 PMCID: PMC5890168 DOI: 10.3389/fcimb.2018.00073] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 02/27/2018] [Indexed: 11/15/2022] Open
Abstract
Due to their archaic life style and microbivor behavior, amoebae may represent a source of antimicrobial peptides and proteins. The amoebic protozoon Dictyostelium discoideum has been a model organism in cell biology for decades and has recently also been used for research on host-pathogen interactions and the evolution of innate immunity. In the genome of D. discoideum, genes can be identified that potentially allow the synthesis of a variety of antimicrobial proteins. However, at the protein level only very few antimicrobial proteins have been characterized that may interact directly with bacteria and help in fighting infection of D. discoideum with potential pathogens. Here, we focus on a large group of gene products that structurally belong to the saposin-like protein (SAPLIP) family and which members we named provisionally Apls (amoebapore-like peptides) according to their similarity to a comprehensively studied antimicrobial and cytotoxic pore-forming protein of the protozoan parasite Entamoeba histolytica. We focused on AplD because it is the only Apl gene that is reported to be primarily transcribed further during the multicellular stages such as the mobile slug stage. Upon knock-out (KO) of the gene, aplD− slugs became highly vulnerable to virulent Klebsiella pneumoniae. AplD− slugs harbored bacterial clumps in their interior and were unable to slough off the pathogen in their slime sheath. Re-expression of AplD in aplD− slugs rescued the susceptibility toward K. pneumoniae. The purified recombinant protein rAplD formed pores in liposomes and was also capable of permeabilizing the membrane of live Bacillus megaterium. We propose that the multifarious Apl family of D. discoideum comprises antimicrobial effector polypeptides that are instrumental to interact with bacteria and their phospholipid membranes. The variety of its members would allow a complementary and synergistic action against a variety of microbes, which the amoeba encounters in its environment.
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Affiliation(s)
| | - Moritz Bitzhenner
- Zoological Institute, Comparative Immunobiology, University of Kiel, Kiel, Germany
| | - Pierre Cosson
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Thierry Soldati
- Department of Biochemistry, Faculty of Science, University of Geneva, Geneva, Switzerland
| | - Matthias Leippe
- Zoological Institute, Comparative Immunobiology, University of Kiel, Kiel, Germany
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Rémy B, Mion S, Plener L, Elias M, Chabrière E, Daudé D. Interference in Bacterial Quorum Sensing: A Biopharmaceutical Perspective. Front Pharmacol 2018; 9:203. [PMID: 29563876 PMCID: PMC5845960 DOI: 10.3389/fphar.2018.00203] [Citation(s) in RCA: 160] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 02/22/2018] [Indexed: 12/12/2022] Open
Abstract
Numerous bacteria utilize molecular communication systems referred to as quorum sensing (QS) to synchronize the expression of certain genes regulating, among other aspects, the expression of virulence factors and the synthesis of biofilm. To achieve this process, bacteria use signaling molecules, known as autoinducers (AIs), as chemical messengers to share information. Naturally occurring strategies that interfere with bacterial signaling have been extensively studied in recent years, examining their potential to control bacteria. To interfere with QS, bacteria use quorum sensing inhibitors (QSIs) to block the action of AIs and quorum quenching (QQ) enzymes to degrade signaling molecules. Recent studies have shown that these strategies are promising routes to decrease bacterial pathogenicity and decrease biofilms, potentially enhancing bacterial susceptibility to antimicrobial agents including antibiotics and bacteriophages. The efficacy of QSIs and QQ enzymes has been demonstrated in various animal models and are now considered in the development of new medical devices against bacterial infections, including dressings, and catheters for enlarging the therapeutic arsenal against bacteria.
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Affiliation(s)
- Benjamin Rémy
- IRD, APHM, MEPHI, IHU-Méditerranée Infection, Aix Marseille Université, Marseille, France
- Gene&GreenTK, Marseille, France
| | - Sonia Mion
- IRD, APHM, MEPHI, IHU-Méditerranée Infection, Aix Marseille Université, Marseille, France
| | | | - Mikael Elias
- Department of Biochemistry, Molecular Biology and Biophysics, Biotechnology Institute, University of Minnesota, St. Paul, MN, United States
| | - Eric Chabrière
- IRD, APHM, MEPHI, IHU-Méditerranée Infection, Aix Marseille Université, Marseille, France
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31
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Marcoleta AE, Varas MA, Ortiz-Severín J, Vásquez L, Berríos-Pastén C, Sabag AV, Chávez FP, Allende ML, Santiviago CA, Monasterio O, Lagos R. Evaluating Different Virulence Traits of Klebsiella pneumoniae Using Dictyostelium discoideum and Zebrafish Larvae as Host Models. Front Cell Infect Microbiol 2018; 8:30. [PMID: 29479519 PMCID: PMC5811510 DOI: 10.3389/fcimb.2018.00030] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 01/23/2018] [Indexed: 01/26/2023] Open
Abstract
Multiresistant and invasive hypervirulent Klebsiella pneumoniae strains have become one of the most urgent bacterial pathogen threats. Recent analyses revealed a high genomic plasticity of this species, harboring a variety of mobile genetic elements associated with virulent strains, encoding proteins of unknown function whose possible role in pathogenesis have not been addressed. K. pneumoniae virulence has been studied mainly in animal models such as mice and pigs, however, practical, financial, ethical and methodological issues limit the use of mammal hosts. Consequently, the development of simple and cost-effective experimental approaches with alternative host models is needed. In this work we described the use of both, the social amoeba and professional phagocyte Dictyostelium discoideum and the fish Danio rerio (zebrafish) as surrogate host models to study K. pneumoniae virulence. We compared three K. pneumoniae clinical isolates evaluating their resistance to phagocytosis, intracellular survival, lethality, intestinal colonization, and innate immune cells recruitment. Optical transparency of both host models permitted studying the infective process in vivo, following the Klebsiella-host interactions through live-cell imaging. We demonstrated that K. pneumoniae RYC492, but not the multiresistant strains 700603 and BAA-1705, is virulent to both host models and elicits a strong immune response. Moreover, this strain showed a high resistance to phagocytosis by D. discoideum, an increased ability to form biofilms and a more prominent and irregular capsule. Besides, the strain 700603 showed the unique ability to replicate inside amoeba cells. Genomic comparison of the K. pneumoniae strains showed that the RYC492 strain has a higher overall content of virulence factors although no specific genes could be linked to its phagocytosis resistance, nor to the intracellular survival observed for the 700603 strain. Our results indicate that both zebrafish and D. discoideum are advantageous host models to study different traits of K. pneumoniae that are associated with virulence.
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Affiliation(s)
- Andrés E Marcoleta
- Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Macarena A Varas
- Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Javiera Ortiz-Severín
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Leonardo Vásquez
- Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Camilo Berríos-Pastén
- Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Andrea V Sabag
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Francisco P Chávez
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Miguel L Allende
- Departamento de Biología, Facultad de Ciencias, Centro FONDAP de Regulación del Genoma, Universidad de Chile, Santiago, Chile
| | - Carlos A Santiviago
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Octavio Monasterio
- Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Rosalba Lagos
- Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
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Varas MA, Riquelme-Barrios S, Valenzuela C, Marcoleta AE, Berríos-Pastén C, Santiviago CA, Chávez FP. Inorganic Polyphosphate Is Essential for Salmonella Typhimurium Virulence and Survival in Dictyostelium discoideum. Front Cell Infect Microbiol 2018; 8:8. [PMID: 29441327 PMCID: PMC5797601 DOI: 10.3389/fcimb.2018.00008] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 01/09/2018] [Indexed: 01/26/2023] Open
Abstract
Inorganic polyphosphate (polyP) deficiency in enteric bacterial pathogens reduces their ability to invade and establish systemic infections in different hosts. For instance, inactivation of the polyP kinase gene (ppk) encoding the enzyme responsible for polyP biosynthesis reduces invasiveness and intracellular survival of Salmonella enterica serovar Typhimurium (S. Typhimurium) in epithelial cells and macrophages in vitro. In addition, the virulence in vivo of a S. Typhimurium Δppk mutant is significantly reduced in a murine infection model. In spite of these observations, the role played by polyP during the Salmonella-host interaction is not well understood. The social amoeba Dictyostelium discoideum has proven to be a useful model for studying relevant aspects of the host-pathogen interaction. In fact, many intracellular pathogens can survive within D. discoideum cells using molecular mechanisms also required to survive within macrophages. Recently, we established that S. Typhimurium is able to survive intracellularly in D. discoideum and identified relevant genes linked to virulence that are crucial for this process. The aim of this study was to determine the effect of a polyP deficiency in S. Typhimurium during its interaction with D. discoideum. To do this, we evaluated the intracellular survival of wild-type and Δppk strains of S. Typhimurium in D. discoideum and the ability of these strains to delay the social development of the amoeba. In contrast to the wild-type strain, the Δppk mutant was unable to survive intracellularly in D. discoideum and enabled the social development of the amoeba. Both phenotypes were complemented using a plasmid carrying a copy of the ppk gene. Next, we simultaneously evaluated the proteomic response of both S. Typhimurium and D. discoideum during host-pathogen interaction via global proteomic profiling. The analysis of our results allowed the identification of novel molecular signatures that give insight into Salmonella-Dictyostelium interaction. Altogether, our results indicate that inorganic polyP is essential for S. Typhimurium virulence and survival in D. discoideum. In addition, we have validated the use of global proteomic analyses to simultaneously evaluate the host-pathogen interaction of S. Typhimurium and D. discoideum. Furthermore, our infection assays using these organisms can be exploited to screen for novel anti-virulence molecules targeting inorganic polyP biosynthesis.
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Affiliation(s)
- Macarena A Varas
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Sebastián Riquelme-Barrios
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Camila Valenzuela
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Andrés E Marcoleta
- Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Camilo Berríos-Pastén
- Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Carlos A Santiviago
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Francisco P Chávez
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
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33
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Diversity of free-living amoebae in soils and their associated human opportunistic bacteria. Parasitol Res 2017; 116:3151-3162. [DOI: 10.1007/s00436-017-5632-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 09/21/2017] [Indexed: 02/06/2023]
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Brenz Y, Winther-Larsen HC, Hagedorn M. Expanding Francisella models: Pairing up the soil amoeba Dictyostelium with aquatic Francisella. Int J Med Microbiol 2017; 308:32-40. [PMID: 28843671 DOI: 10.1016/j.ijmm.2017.08.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 07/31/2017] [Accepted: 08/04/2017] [Indexed: 12/19/2022] Open
Abstract
The bacterial genus Francisella comprises highly pathogenic species that infect mammals, arthropods, fish and protists. Understanding virulence and host defense mechanisms of Francisella infection relies on multiple animal and cellular model systems. In this review, we want to summarize the most commonly used Francisella host model platforms and highlight novel, alternative model systems using aquatic Francisella species. Established mouse and macrophage models contributed extensively to our understanding of Francisella infection. However, murine and human cells display significant differences in their response to Francisella infection. The zebrafish and the amoeba Dictyostelium are well-established model systems for host-pathogen interactions and open up opportunities to investigate bacterial virulence and host defense. Comparisons between model systems using human and fish pathogenic Francisella species revealed shared virulence strategies and pathology between them. Hence, zebrafish and Dictyostelium might complement current model systems to find new vaccine candidates and contribute to our understanding of Francisella infection.
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Affiliation(s)
- Yannick Brenz
- Department of Parasitology, Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Straße 74, 20359 Hamburg, Germany.
| | - Hanne C Winther-Larsen
- Centre for Integrative Microbial Evolution (CIME) and Department of Pharmaceutical Biosciences, University of Oslo, Sem Sælands vei 3, 0371 Oslo, Norway.
| | - Monica Hagedorn
- Department of Life Sciences and Chemistry, Jacobs University, Campus Ring 1, 28759 Bremen, Germany.
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Moussa Z, Chebl M, Patra D. Fluorescence of tautomeric forms of curcumin in different pH and biosurfactant rhamnolipids systems: Application towards on-off ratiometric fluorescence temperature sensing. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2017. [DOI: 10.1016/j.jphotobiol.2017.06.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Metabolic Compensation of Fitness Costs Is a General Outcome for Antibiotic-Resistant Pseudomonas aeruginosa Mutants Overexpressing Efflux Pumps. mBio 2017; 8:mBio.00500-17. [PMID: 28743808 PMCID: PMC5527304 DOI: 10.1128/mbio.00500-17] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
It is generally assumed that the acquisition of antibiotic resistance is associated with a fitness cost. We have shown that overexpression of the MexEF-OprN efflux pump does not decrease the fitness of a resistant Pseudomonas aeruginosa strain compared to its wild-type counterpart. This lack of fitness cost was associated with a metabolic rewiring that includes increased expression of the anaerobic nitrate respiratory chain when cells are growing under fully aerobic conditions. It was not clear whether this metabolic compensation was exclusive to strains overexpressing MexEF-OprN or if it extended to other resistant strains that overexpress similar systems. To answer this question, we studied a set of P. aeruginosa mutants that independently overexpress the MexAB-OprM, MexCD-OprJ, or MexXY efflux pumps. We observed increased expression of the anaerobic nitrate respiratory chain in all cases, with a concomitant increase in NO3 consumption and NO production. These efflux pumps are proton/substrate antiporters, and their overexpression may lead to intracellular H+ accumulation, which may in turn offset the pH homeostasis. Indeed, all studied mutants showed a decrease in intracellular pH under anaerobic conditions. The fastest way to eliminate the excess of protons is by increasing oxygen consumption, a feature also displayed by all analyzed mutants. Taken together, our results support metabolic rewiring as a general mechanism to avoid the fitness costs derived from overexpression of P. aeruginosa multidrug efflux pumps. The development of drugs that block this metabolic “reaccommodation” might help in reducing the persistence and spread of antibiotic resistance elements among bacterial populations. It is widely accepted that the acquisition of resistance confers a fitness cost in such a way that in the absence of antibiotics, resistant populations will be outcompeted by susceptible ones. Based on this assumption, antibiotic cycling regimes have been proposed in the belief that they will reduce the persistence and spread of resistance among bacterial pathogens. Unfortunately, trials testing this possibility have frequently failed, indicating that resistant microorganisms are not always outcompeted by susceptible ones. Indeed, some mutations do not result in a fitness cost, and in case they do, the cost may be compensated for by a secondary mutation. Here we describe an alternative nonmutational mechanism for compensating for fitness costs, which consists of the metabolic rewiring of resistant mutants. Deciphering the mechanisms involved in the compensation of fitness costs of antibiotic-resistant mutants may help in the development of drugs that will reduce the persistence of resistance by increasing said costs.
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Geisinger E, Isberg RR. Interplay Between Antibiotic Resistance and Virulence During Disease Promoted by Multidrug-Resistant Bacteria. J Infect Dis 2017; 215:S9-S17. [PMID: 28375515 DOI: 10.1093/infdis/jiw402] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Diseases caused by antibiotic-resistant bacteria in hospitals are the outcome of complex relationships between several dynamic factors, including bacterial pathogenicity, the fitness costs of resistance in the human host, and selective forces resulting from interventions such as antibiotic therapy. The emergence and fate of mutations that drive antibiotic resistance are governed by these interactions. In this review, we will examine how different forms of antibiotic resistance modulate bacterial fitness and virulence potential, thus influencing the ability of pathogens to evolve in the context of nosocomial infections. We will focus on 3 important multidrug-resistant pathogens that are notoriously problematic in hospitals: Pseudomonas aeruginosa, Acinetobacter baumannii, and Staphylococcus aureus. An understanding of how antibiotic resistance mutations shape the pathobiology of multidrug-resistant infections has the potential to drive novel strategies that can control the development and spread of drug resistance.
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Affiliation(s)
- Edward Geisinger
- Howard Hughes Medical Institute, and.,Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts
| | - Ralph R Isberg
- Howard Hughes Medical Institute, and.,Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts
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38
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Fitness costs associated with the acquisition of antibiotic resistance. Essays Biochem 2017; 61:37-48. [PMID: 28258228 DOI: 10.1042/ebc20160057] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 12/20/2016] [Accepted: 01/03/2017] [Indexed: 01/09/2023]
Abstract
Acquisition of antibiotic resistance is a relevant problem for human health. The selection and spread of antibiotic-resistant organisms not only compromise the treatment of infectious diseases, but also the implementation of different therapeutic procedures as organ transplantation, advanced surgery or chemotherapy, all of which require proficient methods for avoiding infections. It has been generally accepted that the acquisition of antibiotic resistance will produce a general metabolic burden: in the absence of selection, the resistant organisms would be outcompeted by the susceptible ones. If that was always true, discontinuation of antibiotic use would render the disappearance of resistant microorganisms. However, several studies have shown that, once resistance emerges, the recovery of a fully susceptible population even in the absence of antibiotics is not easy. In the present study, we review updated information on the effect of the acquisition of antibiotic resistance in bacterial physiology as well as on the mechanisms that allow the compensation of the fitness costs associated with the acquisition of resistance.
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Leiba J, Sabra A, Bodinier R, Marchetti A, Lima WC, Melotti A, Perrin J, Burdet F, Pagni M, Soldati T, Lelong E, Cosson P. Vps13F links bacterial recognition and intracellular killing in Dictyostelium. Cell Microbiol 2017; 19. [PMID: 28076662 PMCID: PMC5484366 DOI: 10.1111/cmi.12722] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 01/06/2017] [Accepted: 01/06/2017] [Indexed: 12/22/2022]
Abstract
Bacterial sensing, ingestion, and killing by phagocytic cells are essential processes to protect the human body from infectious microorganisms. The cellular mechanisms involved in intracellular killing, their relative importance, and their specificity towards different bacteria are however poorly defined. In this study, we used Dictyostelium discoideum, a phagocytic cell model amenable to genetic analysis, to identify new gene products involved in intracellular killing. A random genetic screen led us to identify the role of Vps13F in intracellular killing of Klebsiella pneumoniae. Vps13F knock‐out (KO) cells exhibited a delayed intracellular killing of K. pneumoniae, although the general organization of the phagocytic and endocytic pathway appeared largely unaffected. Transcriptomic analysis revealed that vps13F KO cells may be functionally similar to previously characterized fspA KO cells, shown to be defective in folate sensing. Indeed, vps13F KO cells showed a decreased chemokinetic response to various stimulants, suggesting a direct or indirect role of Vps13F in intracellular signaling. Overstimulation with excess folate restored efficient killing in vps13F KO cells. Finally, genetic inactivation of Far1, the folate receptor, resulted in inefficient intracellular killing of K. pneumoniae. Together, these observations show that stimulation of Dictyostelium by bacterial folate is necessary for rapid intracellular killing of K. pneumoniae.
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Affiliation(s)
- Jade Leiba
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Ayman Sabra
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Romain Bodinier
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Anna Marchetti
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Wanessa C Lima
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Astrid Melotti
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Jackie Perrin
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Frederic Burdet
- Vital-IT, Swiss Institute of Bioinformatics, University of Lausanne, Lausanne, Switzerland
| | - Marco Pagni
- Vital-IT, Swiss Institute of Bioinformatics, University of Lausanne, Lausanne, Switzerland
| | - Thierry Soldati
- Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Emmanuelle Lelong
- Genomic Research Laboratory, Division of Infectious Diseases, Geneva University Hospitals, Geneva, Switzerland
| | - Pierre Cosson
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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40
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Bravo-Toncio C, Álvarez JA, Campos F, Ortíz-Severín J, Varas M, Cabrera R, Lagos CF, Chávez FP. Dictyostelium discoideum as a surrogate host–microbe model for antivirulence screening in Pseudomonas aeruginosa PAO1. Int J Antimicrob Agents 2016; 47:403-9. [DOI: 10.1016/j.ijantimicag.2016.02.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 02/14/2016] [Accepted: 02/20/2016] [Indexed: 11/25/2022]
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41
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Champion AC, Houston NK, Bradbury RS, Reid DWEC. Preliminary feasibility and modelling of a liquid matrix Dictyostelium discoideum virulence assay for Pseudomonas aeruginosa. Br J Biomed Sci 2016; 73:51-5. [PMID: 27181169 DOI: 10.1080/09674845.2016.1157249] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVES To develop and determine the feasibility of using a liquid matrix adaptation of the Dictyostelium discoideum bacterial virulence assay by testing on well-characterised clinical and environmental isolates of Pseudomonas aeruginosa. MATERIALS AND METHODS Axenic AX2 D. discoideum were co-cultured with clinical and environmental isolates of P. aeruginosa in costar 24-well tissue culture plates for 24 h. A P. aeruginosa PAO1 positive control was tested in biological quintuplicate. Wells were then inspected using an inverted microscope and the degree of cytotoxic changes (sparse growth compared to control combined with rounding of cells and cytoplasmic shrinkage) on the D. discoideum cells was observed. A Klebsiella aerogenes negative control was included with each assay series. RESULTS Sixty-five clinical and 20 environmental P. aeruginosa isolates were tested in the model. Cystic fibrosis respiratory isolates were found to be significantly (P < 0.05) less cytotoxic than P. aeruginosa from other sources. Limitations attached to the funding of this paper did not allow validation against previously employed models or animal models. DISCUSSION A liquid matrix D. discoideum model for the analysis of P. aeruginosa virulence in a eukaryotic host is feasible, but further validation of the model is required before it may be employed in routine setting.
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Affiliation(s)
- Alan Charles Champion
- a School of Medicine , University of Tasmania , Hobart , Australia.,b Faculty of Science, Medicine and Health , University of Wollongong , Wollongong , Australia
| | | | - Richard Stewart Bradbury
- c School of Medical & Applied Sciences , Central Queensland University , Rockhampton , Australia
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A Novel Glycolipid Biosurfactant Confers Grazing Resistance upon Pantoea ananatis BRT175 against the Social Amoeba Dictyostelium discoideum. mSphere 2016; 1:mSphere00075-15. [PMID: 27303689 PMCID: PMC4863597 DOI: 10.1128/msphere.00075-15] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 12/01/2015] [Indexed: 11/20/2022] Open
Abstract
Pantoea is a versatile genus of bacteria with both plant- and animal-pathogenic strains, some of which have been suggested to cause human infections. There is, however, limited knowledge on the potential determinants used for host association and pathogenesis in animal systems. In this study, we used the model host Dictyostelium discoideum to show that isolates of Pantoea ananatis exhibit differential grazing susceptibility, with some being resistant to grazing by the amoebae. We carried out a high-throughput genetic screen of one grazing-resistant isolate, P. ananatis BRT175, using the D. discoideum pathosystem to identify genes responsible for the resistance phenotype. Among the 26 candidate genes involved in grazing resistance, we identified rhlA and rhlB, which we show are involved in the biosynthesis of a biosurfactant that enables swarming motility in P. ananatis BRT175. Using liquid chromatography-mass spectrometry (LC-MS), the biosurfactant was shown to be a glycolipid with monohexose-C10-C10 as the primary congener. We show that this novel glycolipid biosurfactant is cytotoxic to the amoebae and is capable of compromising cellular integrity, leading to cell lysis. The production of this biosurfactant may be important for bacterial survival in the environment and could contribute to the establishment of opportunistic infections. IMPORTANCE The genetic factors used for host interaction by the opportunistic human pathogen Pantoea ananatis are largely unknown. We identified two genes that are important for the production of a biosurfactant that confers grazing resistance against the social amoeba Dictyostelium discoideum. We show that the biosurfactant, which exhibits cytotoxicity toward the amoebae, is a glycolipid that incorporates a hexose rather than rhamnose. The production of this biosurfactant may confer a competitive advantage in the environment and could potentially contribute to the establishment of opportunistic infections.
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Chen YY, Yang FL, Wu SH, Lin TL, Wang JT. Mycobacterium marinum mmar_2318 and mmar_2319 are Responsible for Lipooligosaccharide Biosynthesis and Virulence Toward Dictyostelium. Front Microbiol 2016; 6:1458. [PMID: 26779131 PMCID: PMC4703794 DOI: 10.3389/fmicb.2015.01458] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 12/04/2015] [Indexed: 12/15/2022] Open
Abstract
Resistance to phagocyte killing is an important virulence factor in mycobacteria. Dictyostelium has been used to study the interaction between phagocytes and bacteria, given its similarity to the mammalian macrophage. Here, we investigated the genes responsible for virulence to Dictyostelium by screening 1728 transposon mutants of the Mycobacterium marinum NTUH-M6094 strain. A total of 30 mutants that permissive for Dictyostelium growth were identified. These mutants revealed interruptions in 20 distinct loci. Of the 20 loci, six genes (losA, mmar_2318, mmar_2319, wecE, mmar_2323 and mmar_2353) were located in the lipooligosaccharide (LOS) synthesis cluster. LOS are antigenic glycolipids and the core LOS structure from LOS-I to LOS-IV have been reported to exist in M. marinum. Two-dimensional thin-layer chromatography (2D-TLC) glycolipid profiles revealed that deletion of mmar_2318 or mmar_2319 resulted in the accumulation of LOS-III and deficiency of LOS-IV. Deletion and complementation of mmar_2318 or mmar_2319 confirmed that these genes both contributed to virulence toward Dictyostelium but not entry and replication inside Dictyostelium. Co-incubation with a murine macrophage cell line J774a.1 or PMA-induced human monocytic cell line THP-1 demonstrated that mmar_2318 or mmar_2319 deletion mutant could grow in macrophages, and their initial entry rate was not affected in J774a.1 but significantly increased in THP-1. In conclusion, although mmar_2319 has been reported to involve LOS biosynthesis in a previous study, we identified a new gene, mmar_2318 that is also involved in the biosynthesis of LOS. Deletion of mmar_2318 or mmar_2319 both exhibits reduction of virulence toward Dictyostelium and increased entry into THP-1 cells.
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Affiliation(s)
- Yi-Yin Chen
- Department of Microbiology, National Taiwan University College of Medicine Taipei, Taiwan
| | - Feng-Ling Yang
- Institute of Biological Chemistry, Academia Sinica Taipei, Taiwan
| | - Shih-Hsiung Wu
- Institute of Biological Chemistry, Academia Sinica Taipei, Taiwan
| | - Tzu-Lung Lin
- Department of Microbiology, National Taiwan University College of Medicine Taipei, Taiwan
| | - Jin-Town Wang
- Department of Microbiology, National Taiwan University College of MedicineTaipei, Taiwan; Department of Internal Medicine, National Taiwan University HospitalTaipei, Taiwan
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Okano C, Kato N. Suppressive Effects of Self-Associated Triblock Copolymers on Quorum Sensing-Mediated Phenazine Antibiotic Production. ACTA ACUST UNITED AC 2016. [DOI: 10.14723/tmrsj.41.163] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
| | - Norihiro Kato
- Utsunomiya University
- CREST, Japan Science and Technology Agency
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Dissection of Francisella-Host Cell Interactions in Dictyostelium discoideum. Appl Environ Microbiol 2015; 82:1586-1598. [PMID: 26712555 DOI: 10.1128/aem.02950-15] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 12/22/2015] [Indexed: 12/31/2022] Open
Abstract
Francisella bacteria cause severe disease in both vertebrates and invertebrates and include one of the most infectious human pathogens. Mammalian cell lines have mainly been used to study the mechanisms by which Francisella manipulates its host to replicate within a large variety of hosts and cell types, including macrophages. Here, we describe the establishment of a genetically and biochemically tractable infection model: the amoeba Dictyostelium discoideum combined with the fish pathogen Francisella noatunensis subsp. noatunensis. Phagocytosed F. noatunensis subsp. noatunensis interacts with the endosomal pathway and escapes further phagosomal maturation by translocating into the host cell cytosol. F. noatunensis subsp. noatunensis lacking IglC, a known virulence determinant required for Francisella intracellular replication, follows the normal phagosomal maturation and does not grow in Dictyostelium. The attenuation of the F. noatunensis subsp. noatunensis ΔiglC mutant was confirmed in a zebrafish embryo model, where growth of F. noatunensis subsp. noatunensis ΔiglC was restricted. In Dictyostelium, F. noatunensis subsp. noatunensis interacts with the autophagic machinery. The intracellular bacteria colocalize with autophagic markers, and when autophagy is impaired (Dictyostelium Δatg1), F. noatunensis subsp. noatunensis accumulates within Dictyostelium cells. Altogether, the Dictyostelium-F. noatunensis subsp. noatunensis infection model recapitulates the course of infection described in other host systems. The genetic and biochemical tractability of the system allows new approaches to elucidate the dynamic interactions between pathogenic Francisella and its host organism.
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46
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Connelly BD, Dickinson KJ, Hammarlund SP, Kerr B. Negative niche construction favors the evolution of cooperation. Evol Ecol 2015. [DOI: 10.1007/s10682-015-9803-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Song C, Mazzola M, Cheng X, Oetjen J, Alexandrov T, Dorrestein P, Watrous J, van der Voort M, Raaijmakers JM. Molecular and chemical dialogues in bacteria-protozoa interactions. Sci Rep 2015; 5:12837. [PMID: 26246193 PMCID: PMC4542665 DOI: 10.1038/srep12837] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 07/10/2015] [Indexed: 12/23/2022] Open
Abstract
Protozoan predation of bacteria can significantly affect soil microbial community composition and ecosystem functioning. Bacteria possess diverse defense strategies to resist or evade protozoan predation. For soil-dwelling Pseudomonas species, several secondary metabolites were proposed to provide protection against different protozoan genera. By combining whole-genome transcriptome analyses with (live) imaging mass spectrometry (IMS), we observed multiple changes in the molecular and chemical dialogues between Pseudomonas fluorescens and the protist Naegleria americana. Lipopeptide (LP) biosynthesis was induced in Pseudomonas upon protozoan grazing and LP accumulation transitioned from homogeneous distributions across bacterial colonies to site-specific accumulation at the bacteria-protist interface. Also putrescine biosynthesis was upregulated in P. fluorescens upon predation. We demonstrated that putrescine induces protozoan trophozoite encystment and adversely affects cyst viability. This multifaceted study provides new insights in common and strain-specific responses in bacteria-protozoa interactions, including responses that contribute to bacterial survival in highly competitive soil and rhizosphere environments.
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Affiliation(s)
- Chunxu Song
- 1] Laboratory of Phytopathology, Wageningen University, 6708 PB Wageningen, the Netherlands [2] Microbial Ecology Department, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB Wageningen, the Netherlands
| | - Mark Mazzola
- USDA-ARS, 1104 N. Western Ave., Wenatchee, Washington 98801
| | - Xu Cheng
- Laboratory of Phytopathology, Wageningen University, 6708 PB Wageningen, the Netherlands
| | - Janina Oetjen
- Center for Industrial Mathematics, University of Bremen, 28359 Bremen, Germany
| | - Theodore Alexandrov
- 1] MALDI Imaging Lab, University of Bremen, 28359 Bremen, Germany [2] Center for Industrial Mathematics, University of Bremen, 28359 Bremen, Germany [3] SCiLS GmbH, 28359 Bremen, Germany [4] Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego , San Diego, California 92093, United States [5] Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
| | - Pieter Dorrestein
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego , San Diego, California 92093, United States
| | - Jeramie Watrous
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego , San Diego, California 92093, United States
| | - Menno van der Voort
- Laboratory of Phytopathology, Wageningen University, 6708 PB Wageningen, the Netherlands
| | - Jos M Raaijmakers
- 1] Laboratory of Phytopathology, Wageningen University, 6708 PB Wageningen, the Netherlands [2] Microbial Ecology Department, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB Wageningen, the Netherlands
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Dubern JF, Cigana C, De Simone M, Lazenby J, Juhas M, Schwager S, Bianconi I, Döring G, Eberl L, Williams P, Bragonzi A, Cámara M. Integrated whole-genome screening for Pseudomonas aeruginosa virulence genes using multiple disease models reveals that pathogenicity is host specific. Environ Microbiol 2015; 17:4379-93. [PMID: 25845292 PMCID: PMC4676916 DOI: 10.1111/1462-2920.12863] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 03/19/2015] [Accepted: 03/31/2015] [Indexed: 11/28/2022]
Abstract
Pseudomonas aeruginosa is a multi-host opportunistic pathogen causing a wide range of diseases because of the armoury of virulence factors it produces, and it is difficult to eradicate because of its intrinsic resistance to antibiotics. Using an integrated whole-genome approach, we searched for P. aeruginosa virulence genes with multi-host relevance. We constructed a random library of 57 360 Tn5 mutants in P. aeruginosa PAO1-L and screened it in vitro for those showing pleiotropic effects in virulence phenotypes (reduced swarming, exo-protease and pyocyanin production). A set of these pleiotropic mutants were assayed for reduced toxicity in Drosophila melanogaster, Caenorhabditis elegans, human cell lines and mice. Surprisingly, the screening revealed that the virulence of the majority of P. aeruginosa mutants varied between disease models, suggesting that virulence is dependent on the disease model used and hence the host environment. Genomic analysis revealed that these virulence-related genes encoded proteins from almost all functional classes, which were conserved among P. aeruginosa strains. Thus, we provide strong evidence that although P. aeruginosa is capable of infecting a wide range of hosts, many of its virulence determinants are host specific. These findings have important implication when searching for novel anti-virulence targets to develop new treatments against P. aeruginosa.
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Affiliation(s)
- Jean-Frédéric Dubern
- School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, UK
| | - Cristina Cigana
- Division of Immunology, Transplantation and Infectious Diseases, IRCCS, San Raffaele Scientific Institute, Milano, Italy
| | - Maura De Simone
- Division of Immunology, Transplantation and Infectious Diseases, IRCCS, San Raffaele Scientific Institute, Milano, Italy
| | - James Lazenby
- School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, UK
| | - Mario Juhas
- Department of Microbiology, Institute of Plant Biology, University of Zürich, Zürich, Switzerland
| | - Stephan Schwager
- Department of Microbiology, Institute of Plant Biology, University of Zürich, Zürich, Switzerland
| | - Irene Bianconi
- Division of Immunology, Transplantation and Infectious Diseases, IRCCS, San Raffaele Scientific Institute, Milano, Italy
| | - Gerd Döring
- Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany
| | - Leo Eberl
- Department of Microbiology, Institute of Plant Biology, University of Zürich, Zürich, Switzerland
| | - Paul Williams
- School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, UK
| | - Alessandra Bragonzi
- Division of Immunology, Transplantation and Infectious Diseases, IRCCS, San Raffaele Scientific Institute, Milano, Italy
| | - Miguel Cámara
- School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, UK
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Li XZ, Plésiat P, Nikaido H. The challenge of efflux-mediated antibiotic resistance in Gram-negative bacteria. Clin Microbiol Rev 2015; 28:337-418. [PMID: 25788514 PMCID: PMC4402952 DOI: 10.1128/cmr.00117-14] [Citation(s) in RCA: 891] [Impact Index Per Article: 99.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The global emergence of multidrug-resistant Gram-negative bacteria is a growing threat to antibiotic therapy. The chromosomally encoded drug efflux mechanisms that are ubiquitous in these bacteria greatly contribute to antibiotic resistance and present a major challenge for antibiotic development. Multidrug pumps, particularly those represented by the clinically relevant AcrAB-TolC and Mex pumps of the resistance-nodulation-division (RND) superfamily, not only mediate intrinsic and acquired multidrug resistance (MDR) but also are involved in other functions, including the bacterial stress response and pathogenicity. Additionally, efflux pumps interact synergistically with other resistance mechanisms (e.g., with the outer membrane permeability barrier) to increase resistance levels. Since the discovery of RND pumps in the early 1990s, remarkable scientific and technological advances have allowed for an in-depth understanding of the structural and biochemical basis, substrate profiles, molecular regulation, and inhibition of MDR pumps. However, the development of clinically useful efflux pump inhibitors and/or new antibiotics that can bypass pump effects continues to be a challenge. Plasmid-borne efflux pump genes (including those for RND pumps) have increasingly been identified. This article highlights the recent progress obtained for organisms of clinical significance, together with methodological considerations for the characterization of MDR pumps.
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Affiliation(s)
- Xian-Zhi Li
- Human Safety Division, Veterinary Drugs Directorate, Health Products and Food Branch, Health Canada, Ottawa, Ontario, Canada
| | - Patrick Plésiat
- Laboratoire de Bactériologie, Faculté de Médecine-Pharmacie, Centre Hospitalier Régional Universitaire, Université de Franche-Comté, Besançon, France
| | - Hiroshi Nikaido
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
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Type III secretion system and virulence markers highlight similarities and differences between human- and plant-associated pseudomonads related to Pseudomonas fluorescens and P. putida. Appl Environ Microbiol 2015; 81:2579-90. [PMID: 25636837 DOI: 10.1128/aem.04160-14] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Pseudomonas fluorescens is commonly considered a saprophytic rhizobacterium devoid of pathogenic potential. Nevertheless, the recurrent isolation of strains from clinical human cases could indicate the emergence of novel strains originating from the rhizosphere reservoir, which could be particularly resistant to the immune system and clinical treatment. The importance of type three secretion systems (T3SSs) in the related Pseudomonas aeruginosa nosocomial species and the occurrence of this secretion system in plant-associated P. fluorescens raise the question of whether clinical isolates may also harbor T3SSs. In this study, isolates associated with clinical infections and identified in hospitals as belonging to P. fluorescens were compared with fluorescent pseudomonads harboring T3SSs isolated from plants. Bacterial isolates were tested for (i) their genetic relationships based on their 16S rRNA phylogeny, (ii) the presence of T3SS genes by PCR, and (iii) their infectious potential on animals and plants under environmental or physiological temperature conditions. Two groups of bacteria were delineated among the clinical isolates. The first group encompassed thermotolerant (41°C) isolates from patients suffering from blood infections; these isolates were finally found to not belong to P. fluorescens but were closely related and harbored highly conserved T3SS genes belonging to the Ysc-T3SS family, like the T3SSs from P. aeruginosa. The second group encompassed isolates from patients suffering from cystic fibrosis; these isolates belonged to P. fluorescens and harbored T3SS genes belonging to the Hrp1-T3SS family found commonly in plant-associated P. fluorescens.
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