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Palanisamy R, Zhang Y, Zhang G. Role of Type 4B Secretion System Protein, IcmE, in the Pathogenesis of Coxiella burnetii. Pathogens 2024; 13:405. [PMID: 38787259 PMCID: PMC11123719 DOI: 10.3390/pathogens13050405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 05/02/2024] [Accepted: 05/10/2024] [Indexed: 05/25/2024] Open
Abstract
Coxiella burnetii is an obligate intracellular Gram-negative bacterium that causes Q fever, a life-threatening zoonotic disease. C. burnetii replicates within an acidified parasitophorous vacuole derived from the host lysosome. The ability of C. burnetii to replicate and achieve successful intracellular life in the cell cytosol is vastly dependent on the Dot/Icm type 4B secretion system (T4SSB). Although several T4SSB effector proteins have been shown to be important for C. burnetii virulence and intracellular replication, the role of the icmE protein in the host-C. burnetii interaction has not been investigated. In this study, we generated a C. burnetii Nine Mile Phase II (NMII) mutant library and identified 146 transposon mutants with a single transposon insertion. Transposon mutagenesis screening revealed that disruption of icmE gene resulted in the attenuation of C. burnetii NMII virulence in SCID mice. ELISA analysis indicated that the levels of pro-inflammatory cytokines, including interleukin-1β, IFN-γ, TNF-α, and IL-12p70, in serum from Tn::icmE mutant-infected SCID mice were significantly lower than those in serum from wild-type (WT) NMII-infected mice. Additionally, Tn::icmE mutant bacteria were unable to replicate in mouse bone marrow-derived macrophages (MBMDM) and human macrophage-like cells (THP-1). Immunoblotting results showed that the Tn::icmE mutant failed to activate inflammasome components such as IL-1β, caspase 1, and gasdermin-D in THP-1 macrophages. Collectively, these results suggest that the icmE protein may play a vital role in C. burnetii virulence, intracellular replication, and activation of inflammasome mediators during NMII infection.
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Affiliation(s)
| | | | - Guoquan Zhang
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX 78249, USA
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2
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Fajardo-Lubian A, Venturini C. Use of Bacteriophages to Target Intracellular Pathogens. Clin Infect Dis 2023; 77:S423-S432. [PMID: 37932114 DOI: 10.1093/cid/ciad515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023] Open
Abstract
Bacteriophages (phages) have shown great potential as natural antimicrobials against extracellular pathogens (eg, Escherichia coli or Klebsiella pneumoniae), but little is known about how they interact with intracellular targets (eg, Shigella spp., Salmonella spp., Mycobacterium spp.) in the mammalian host. Recent research has demonstrated that phages can enter human cells. However, for the design of successful clinical applications, further investigation is required to define their subcellular behavior and to understand the complex biological processes that underlie the interaction with their bacterial targets. In this review, we summarize the molecular evidence of phage internalization in eucaryotic cells, with specific focus on proof of phage activity against their bacterial targets within the eucaryotic host, and the current proposed strategies to overcome poor penetrance issues that may impact therapeutic use against the most clinically relevant intracellular pathogens.
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Affiliation(s)
- Alicia Fajardo-Lubian
- Faculty of Medicine and Health, Sydney ID Institute, University of Sydney, Sydney, New South Wales, Australia
- Centre for Infectious Diseases and Microbiology, Westmead Institute for Medical Research, Westmead, New South Wales, Australia
| | - Carola Venturini
- Centre for Infectious Diseases and Microbiology, Westmead Institute for Medical Research, Westmead, New South Wales, Australia
- Faculty of Science, Sydney School of Veterinary Science, University of Sydney, Sydney, New South Wales, Australia
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3
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Boyer MA, Fischer NL, Shin S. TNF and type I IFN induction of the IRG1-itaconate pathway restricts Coxiella burnetii replication within mouse macrophages. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.07.548079. [PMID: 37461589 PMCID: PMC10350068 DOI: 10.1101/2023.07.07.548079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/23/2023]
Abstract
The intracellular Gram-negative bacterium Coxiella burnetii replicates within macrophages and causes a zoonotic disease known as Q fever. In murine macrophages, the cytokine tumor necrosis factor (TNF) is critical for restriction of intracellular C. burnetii replication. Here, we show that TNF collaborates with type I interferon (IFN) signaling for maximal control of C. burnetii. We found that TNF and type I IFN upregulate the expression of the metabolic enzyme immune responsive gene 1 (IRG1), also known as cis-aconitate decarboxylase 1 (ACOD1), and that IRG1 is required to restrict C. burnetii T4SS translocation and replication within macrophages. Further, we show that itaconic acid, the metabolic product of IRG1, restricts C. burnetii replication both intracellularly and in axenic culture. These data reveal that TNF and type I IFN upregulate the IRG1-itaconate pathway to restrict intracellular C. burnetii replication within murine macrophages.
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Affiliation(s)
- Mark A. Boyer
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104
| | - Natasha Lopes Fischer
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104
| | - Sunny Shin
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104
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4
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Riffaud CM, Rucks EA, Ouellette SP. Persistence of obligate intracellular pathogens: alternative strategies to overcome host-specific stresses. Front Cell Infect Microbiol 2023; 13:1185571. [PMID: 37284502 PMCID: PMC10239878 DOI: 10.3389/fcimb.2023.1185571] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 05/05/2023] [Indexed: 06/08/2023] Open
Abstract
In adapting to the intracellular niche, obligate intracellular bacteria usually undergo a reduction of genome size by eliminating genes not needed for intracellular survival. These losses can include, for example, genes involved in nutrient anabolic pathways or in stress response. Living inside a host cell offers a stable environment where intracellular bacteria can limit their exposure to extracellular effectors of the immune system and modulate or outright inhibit intracellular defense mechanisms. However, highlighting an area of vulnerability, these pathogens are dependent on the host cell for nutrients and are very sensitive to conditions that limit nutrient availability. Persistence is a common response shared by evolutionarily divergent bacteria to survive adverse conditions like nutrient deprivation. Development of persistence usually compromises successful antibiotic therapy of bacterial infections and is associated with chronic infections and long-term sequelae for the patients. During persistence, obligate intracellular pathogens are viable but not growing inside their host cell. They can survive for a long period of time such that, when the inducing stress is removed, reactivation of their growth cycles resumes. Given their reduced coding capacity, intracellular bacteria have adapted different response mechanisms. This review gives an overview of the strategies used by the obligate intracellular bacteria, where known, which, unlike model organisms such as E. coli, often lack toxin-antitoxin systems and the stringent response that have been linked to a persister phenotype and amino acid starvation states, respectively.
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5
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Matthiesen S, Christiansen B, Jahnke R, Zaeck LM, Karger A, Finke S, Franzke K, Knittler MR. TGF-β/IFN-γ Antagonism in Subversion and Self-Defense of Phase II Coxiella burnetii -Infected Dendritic Cells. Infect Immun 2023; 91:e0032322. [PMID: 36688662 PMCID: PMC9933720 DOI: 10.1128/iai.00323-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 12/20/2022] [Indexed: 01/24/2023] Open
Abstract
Dendritic cells (DCs) belong to the first line of innate defense and come into early contact with invading pathogens, including the zoonotic bacterium Coxiella burnetii, the causative agent of Q fever. However, the pathogen-host cell interactions in C. burnetii-infected DCs, particularly the role of mechanisms of immune subversion beyond virulent phase I lipopolysaccharide (LPS), as well as the contribution of cellular self-defense strategies, are not understood. Using phase II Coxiella-infected DCs, we show that impairment of DC maturation and MHC I downregulation is caused by autocrine release and action of immunosuppressive transforming growth factor-β (TGF-β). Our study demonstrates that IFN-γ reverses TGF-β impairment of maturation/MHC I presentation in infected DCs and activates bacterial elimination, predominantly by inducing iNOS/NO. Induced NO synthesis strongly affects bacterial growth and infectivity. Moreover, our studies hint that Coxiella-infected DCs might be able to protect themselves from mitotoxic NO by switching from oxidative phosphorylation to glycolysis, thus ensuring survival in self-defense against C. burnetii. Our results provide new insights into DC subversion by Coxiella and the IFN-γ-mediated targeting of C. burnetii during early steps in the innate immune response.
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Affiliation(s)
- Svea Matthiesen
- Institute of Immunology, Friedrich-Loeffler-Institut, Federal Research Institute of Animal Health, Isle of Riems, Germany
| | - Bahne Christiansen
- Institute of Immunology, Friedrich-Loeffler-Institut, Federal Research Institute of Animal Health, Isle of Riems, Germany
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute of Animal Health, Isle of Riems, Germany
| | - Rico Jahnke
- Institute of Immunology, Friedrich-Loeffler-Institut, Federal Research Institute of Animal Health, Isle of Riems, Germany
| | - Luca M. Zaeck
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute of Animal Health, Isle of Riems, Germany
| | - Axel Karger
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute of Animal Health, Isle of Riems, Germany
| | - Stefan Finke
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute of Animal Health, Isle of Riems, Germany
| | - Kati Franzke
- Institute of Infectology, Friedrich-Loeffler-Institut, Federal Research Institute of Animal Health, Isle of Riems, Germany
| | - Michael R. Knittler
- Institute of Immunology, Friedrich-Loeffler-Institut, Federal Research Institute of Animal Health, Isle of Riems, Germany
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6
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Sobotta K, Bonkowski K, Heydel C, Henning K, Menge C. Phenotype of Coxiella burnetii Strains of Different Sources and Genotypes in Bovine Mammary Gland Epithelial Cells. Pathogens 2022; 11:pathogens11121422. [PMID: 36558755 PMCID: PMC9786247 DOI: 10.3390/pathogens11121422] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 11/16/2022] [Accepted: 11/19/2022] [Indexed: 11/29/2022] Open
Abstract
Despite the high prevalence of C. burnetii in dairy herds and continuous shedding via milk by chronically infected cows, bovine milk is not recognized as a relevant source of human Q fever. We hypothesized that the bovine mammary gland epithelial cell line PS represents a suitable in vitro model for the identification of C. burnetii-strain-specific virulence properties that may account for this discrepancy. Fifteen C. burnetii strains were selected to represent different host species and multiple loci variable number of tandem repeat analysis (MLVA) genotypes (I, II, III and IV). The replication efficiencies of all strains were similar, even though strains of the MLVA-genotype II replicated significantly better than genotype I strains, and bovine and ovine isolates replicated better than caprine ones. Bovine milk isolates replicated with similar efficiencies to isolates from other bovine organs. One sheep isolate (Cb30/14, MLVA type I, isolated from fetal membranes) induced a remarkable up-regulation of IL-1β and TNF-α, whereas prototypic strains and bovine milk isolates tended to suppress pro-inflammatory responses. While infection with strain Nine Mile I rendered the cells partially refractory to re-stimulation with E. coli lipopolysaccharide, Cb30/14 exerted a selective suppressive effect which was restricted to IL-6 and TNF-α and spared IL-1β. PS cells support the replication of different strains of C. burnetii and respond in a strain-specific manner, but isolates from bovine milk did not display a common pattern, which distinguishes them from strains identified as a public health concern.
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Affiliation(s)
- Katharina Sobotta
- Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut, Naumburger Strasse 96a, 07743 Jena, Germany
| | - Katharina Bonkowski
- Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut, Naumburger Strasse 96a, 07743 Jena, Germany
| | - Carsten Heydel
- Institute for Hygiene and Infectious Diseases of Animals, Justus-Liebig-University (JLU), Frankfurter Strasse 85-89, 35392 Giessen, Germany
| | - Klaus Henning
- Institute of Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institut, Naumburger Strasse 96a, 07743 Jena, Germany
| | - Christian Menge
- Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut, Naumburger Strasse 96a, 07743 Jena, Germany
- Correspondence:
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7
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Developmental Transitions Coordinate Assembly of the Coxiella burnetii Dot/Icm Type IV Secretion System. Infect Immun 2022; 90:e0041022. [PMID: 36190257 PMCID: PMC9584302 DOI: 10.1128/iai.00410-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Coxiella burnetii is an obligate intracellular bacterial pathogen that has evolved a unique biphasic developmental cycle. The infectious form of C. burnetii is the dormant small cell variant (SCV), which transitions to a metabolically active large cell variant (LCV) that replicates inside the lysosome-derived host vacuole. A Dot/Icm type IV secretion system (T4SS), which can deliver over 100 effector proteins to host cells, is essential for the biogenesis of the vacuole and intracellular replication. How the distinct C. burnetii life cycle impacts the assembly and function of the Dot/Icm T4SS has remained unknown. Here, we combine advanced cryo-focused ion beam (cryo-FIB) milling and cryo-electron tomography (cryo-ET) imaging to visualize all developmental transitions and the assembly of the Dot/Icm T4SS in situ. Importantly, assembled Dot/Icm machines were not present in the infectious SCV. The appearance of the assembled Dot/Icm machine correlated with the transition of the SCV to the LCV intracellularly. Furthermore, temporal characterization of C. burnetii morphological changes revealed regions of the inner membrane that invaginate to form tightly packed stacks during the LCV-to-SCV transition at late stages of infection, which may enable the SCV-to-LCV transition that occurs upon infection of a new host cell. Overall, these data establish how C. burnetii developmental transitions control critical bacterial processes to promote intracellular replication and transmission.
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8
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Unger N, Eiserloh S, Nowak F, Zuchantke S, Liebler-Tenorio E, Sobotta K, Schnee C, Berens C, Neugebauer U. Looking Inside Non-Destructively: Label-Free, Raman-Based Visualization of Intracellular Coxiella burnetii. Anal Chem 2022; 94:4988-4996. [PMID: 35302749 PMCID: PMC8974703 DOI: 10.1021/acs.analchem.1c04754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The life cycle of intracellular pathogens is often complex and can include different morphoforms. Treatment of intracellular infections and unperturbed studying of the pathogen inside the host cell are frequently challenging. Here, we present a Raman-based, label-free, non-invasive, and non-destructive method to localize, visualize, and even quantify intracellular bacteria in 3D within intact host cells in a Coxiella burnetii infection model. C. burnetii is a zoonotic obligate intracellular pathogen that causes infections in ruminant livestock and humans with an acute disease known as Q fever. Using statistical data analysis, no isolation is necessary to gain detailed information on the intracellular pathogen's metabolic state. High-quality false color image stacks with diffraction-limited spatial resolution enable a 3D spatially resolved single host cell analysis that shows excellent agreement with results from transmission electron microscopy. Quantitative analysis at different time points post infection allows to follow the infection cycle with the transition from the large cell variant (LCV) to the small cell variant (SCV) at around day 6 and a gradual change in the lipid composition during vacuole maturation. Spectral characteristics of intracellular LCV and SCV reveal a higher lipid content of the metabolically active LCV.
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Affiliation(s)
- Nancy Unger
- Center for Sepsis Control and Care, Jena University Hospital, 07747 Jena, Germany.,Leibniz Institute of Photonic Technology, 07745 Jena, Germany
| | - Simone Eiserloh
- Center for Sepsis Control and Care, Jena University Hospital, 07747 Jena, Germany.,Leibniz Institute of Photonic Technology, 07745 Jena, Germany
| | - Frauke Nowak
- Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut─Federal Research Institute for Animal Health (FLI), 07743 Jena, Germany
| | - Sara Zuchantke
- Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut─Federal Research Institute for Animal Health (FLI), 07743 Jena, Germany
| | - Elisabeth Liebler-Tenorio
- Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut─Federal Research Institute for Animal Health (FLI), 07743 Jena, Germany
| | - Katharina Sobotta
- Institute of Medical Microbiology, Jena University Hospital, 07747 Jena, Germany
| | - Christiane Schnee
- Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut─Federal Research Institute for Animal Health (FLI), 07743 Jena, Germany
| | - Christian Berens
- Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut─Federal Research Institute for Animal Health (FLI), 07743 Jena, Germany
| | - Ute Neugebauer
- Center for Sepsis Control and Care, Jena University Hospital, 07747 Jena, Germany.,Leibniz Institute of Photonic Technology, 07745 Jena, Germany.,Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, 07743 Jena, Germany
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9
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Loterio RK, Zamboni DS, Newton HJ. Keeping the host alive - lessons from obligate intracellular bacterial pathogens. Pathog Dis 2021; 79:6424899. [PMID: 34755855 DOI: 10.1093/femspd/ftab052] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 11/04/2021] [Indexed: 01/20/2023] Open
Abstract
Mammals have evolved sophisticated host cell death signaling pathways as an important immune mechanism to recognize and eliminate cell intruders before they establish their replicative niche. However, intracellular bacterial pathogens that have co-evolved with their host have developed a multitude of tactics to counteract this defense strategy to facilitate their survival and replication. This requires manipulation of pro-death and pro-survival host signaling pathways during infection. Obligate intracellular bacterial pathogens are organisms that absolutely require an eukaryotic host to survive and replicate, and therefore they have developed virulence factors to prevent diverse forms of host cell death and conserve their replicative niche. This review encapsulates our current understanding of these host-pathogen interactions by exploring the most relevant findings of Anaplasma spp., Chlamydia spp., Rickettsia spp. and Coxiella burnetii modulating host cell death pathways. A detailed comprehension of the molecular mechanisms through which these obligate intracellular pathogens manipulate regulated host cell death will not only increase the current understanding of these difficult-to-study pathogens but also provide insights into new tools to study regulated cell death and the development of new therapeutic approaches to control infection.
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Affiliation(s)
- Robson Kriiger Loterio
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto Medical School, FMRP/USP. Av. Bandeirantes 3900, Ribeirão Preto, SP 14049-900, Brazil.,Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, 792 Elizabeth Street, Melbourne, 3000, Victoria, Australia
| | - Dario S Zamboni
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto Medical School, FMRP/USP. Av. Bandeirantes 3900, Ribeirão Preto, SP 14049-900, Brazil
| | - Hayley J Newton
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, 792 Elizabeth Street, Melbourne, 3000, Victoria, Australia
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10
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Kovacs-Simon A, Metters G, Norville I, Hemsley C, Titball RW. Coxiella burnetii replicates in Galleria mellonella hemocytes and transcriptome mapping reveals in vivo regulated genes. Virulence 2021; 11:1268-1278. [PMID: 32970966 PMCID: PMC7549970 DOI: 10.1080/21505594.2020.1819111] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Larvae of the greater wax moth (Galleria mellonella) are susceptible to infection with C. burnetii, an obligate intracellular bacterial pathogen. We show that bacteria are found in hemocytes after infection, and occupy vacuoles which are morphologically similar to Coxiella-containing vacuoles seen in infected mammalian phagocytes. We characterized the infection by transcriptome profiling of bacteria isolated from the hemocytes of infected larvae and identified 46 highly upregulated genes. The encoded proteins are predicted to be involved in translation, LPS biosynthesis, biotin synthesis, scavenging of reactive oxygen species, and included a T4SS effector and 30 hypothetical proteins. Some of these genes had previously been shown to be upregulated in buffalo green monkey (BGM) cells or in mice, whilst others appear to be regulated in a host-specific manner. Altogether, our results demonstrate the value of the G. mellonella model to study intracellular growth and identify potential virulence factors of C. burnetii.
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Affiliation(s)
- Andrea Kovacs-Simon
- College of Life and Environmental Sciences - Biosciences, University of Exeter , Exeter, UK
| | - Georgie Metters
- College of Life and Environmental Sciences - Biosciences, University of Exeter , Exeter, UK
| | - Isobel Norville
- CBR Division, Defence Science and Technology Laboratory , Porton Down,Salisbury, UK
| | - Claudia Hemsley
- College of Life and Environmental Sciences - Biosciences, University of Exeter , Exeter, UK
| | - Richard W Titball
- College of Life and Environmental Sciences - Biosciences, University of Exeter , Exeter, UK
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11
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Jaboulay C, Godeux AS, Doublet P, Vianney A. Regulatory Networks of the T4SS Control: From Host Cell Sensing to the Biogenesis and the Activity during the Infection. J Mol Biol 2021; 433:166892. [PMID: 33636165 DOI: 10.1016/j.jmb.2021.166892] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 02/17/2021] [Accepted: 02/17/2021] [Indexed: 02/03/2023]
Abstract
Delivery of effectors, DNA or proteins, that hijack host cell processes to the benefit of bacteria is a mechanism widely used by bacterial pathogens. It is achieved by complex effector injection devices, the secretion systems, among which Type 4 Secretion Systems (T4SSs) play a key role in bacterial virulence of numerous animal and plant pathogens. Considerable progress has recently been made in the structure-function analyses of T4SSs. Nevertheless, the signals and processes that trigger machine assembly and activity during infection, as well as those involved in substrate recognition and transfer, are complex and still poorly understood. In this review, we aim at summarizing the last updates of the knowledge on signaling pathways that regulate the biogenesis and the activity of T4SSs in important bacterial pathogens.
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Affiliation(s)
- C Jaboulay
- CIRI, Centre International de Recherche en Infectiologie, (Team: Legionella pathogenesis), Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, F-69007 Lyon, France.
| | - A S Godeux
- CIRI, Centre International de Recherche en Infectiologie, (Team: Horigene), Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, F-69007 Lyon, France
| | - P Doublet
- CIRI, Centre International de Recherche en Infectiologie, (Team: Legionella pathogenesis), Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, F-69007 Lyon, France
| | - A Vianney
- CIRI, Centre International de Recherche en Infectiologie, (Team: Legionella pathogenesis), Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, F-69007 Lyon, France
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12
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Fielden LF, Scott NE, Palmer CS, Khoo CA, Newton HJ, Stojanovski D. Proteomic Identification of Coxiella burnetii Effector Proteins Targeted to the Host Cell Mitochondria During Infection. Mol Cell Proteomics 2020; 20:100005. [PMID: 33177156 PMCID: PMC7950127 DOI: 10.1074/mcp.ra120.002370] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 11/11/2020] [Indexed: 11/06/2022] Open
Abstract
Modulation of the host cell is integral to the survival and replication of microbial pathogens. Several intracellular bacterial pathogens deliver bacterial proteins, termed "effector proteins" into the host cell during infection by sophisticated protein translocation systems, which manipulate cellular processes and functions. The functional contribution of individual effectors is poorly characterized, particularly in intracellular bacterial pathogens with large effector protein repertoires. Technical caveats have limited the capacity to study these proteins during a native infection, with many effector proteins having only been demonstrated to be translocated during over-expression of tagged versions. Here, we developed a novel strategy to examine effector proteins in the context of infection. We coupled a broad, unbiased proteomics-based screen with organelle purification to study the host-pathogen interactions occurring between the host cell mitochondrion and the Gram-negative, Q fever pathogen Coxiella burnetii. We identify four novel mitochondrially-targeted C. burnetii effector proteins, renamed Mitochondrial Coxiella effector protein (Mce) B to E. Examination of the subcellular localization of ectopically expressed proteins confirmed their mitochondrial localization, demonstrating the robustness of our approach. Subsequent biochemical analysis and affinity enrichment proteomics of one of these effector proteins, MceC, revealed the protein localizes to the inner membrane and can interact with components of the mitochondrial quality control machinery. Our study adapts high-sensitivity proteomics to study intracellular host-pathogen interactions, providing a robust strategy to examine the subcellular localization of effector proteins during native infection. This approach could be applied to a range of pathogens and host cell compartments to provide a rich map of effector dynamics throughout infection.
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Affiliation(s)
- Laura F Fielden
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Nichollas E Scott
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Catherine S Palmer
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Chen Ai Khoo
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Hayley J Newton
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia.
| | - Diana Stojanovski
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia.
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13
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Coxiella burnetii utilizes both glutamate and glucose during infection with glucose uptake mediated by multiple transporters. Biochem J 2020; 476:2851-2867. [PMID: 31527117 PMCID: PMC6792032 DOI: 10.1042/bcj20190504] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 09/02/2019] [Accepted: 09/16/2019] [Indexed: 12/25/2022]
Abstract
Coxiella burnetii is a Gram-negative bacterium which causes Q fever, a complex and life-threatening infection with both acute and chronic presentations. C. burnetii invades a variety of host cell types and replicates within a unique vacuole derived from the host cell lysosome. In order to understand how C. burnetii survives within this intracellular niche, we have investigated the carbon metabolism of both intracellular and axenically cultivated bacteria. Both bacterial populations were shown to assimilate exogenous [13C]glucose or [13C]glutamate, with concomitant labeling of intermediates in glycolysis and gluconeogenesis, and in the TCA cycle. Significantly, the two populations displayed metabolic pathway profiles reflective of the nutrient availabilities within their propagated environments. Disruption of the C. burnetii glucose transporter, CBU0265, by transposon mutagenesis led to a significant decrease in [13C]glucose utilization but did not abolish glucose usage, suggesting that C. burnetii express additional hexose transporters which may be able to compensate for the loss of CBU0265. This was supported by intracellular infection of human cells and in vivo studies in the insect model showing loss of CBU0265 had no impact on intracellular replication or virulence. Using this mutagenesis and [13C]glucose labeling approach, we identified a second glucose transporter, CBU0347, the disruption of which also showed significant decreases in 13C-label incorporation but did not impact intracellular replication or virulence. Together, these analyses indicate that C. burnetii may use multiple carbon sources in vivo and exhibits greater metabolic flexibility than expected.
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14
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Bitew MA, Wawegama NK, Newton HJ, Sansom FM. Meso-tartrate inhibits intracellular replication of Coxiella burnetii, the causative agent of the zoonotic disease Q fever. Pathog Dis 2020; 77:5679890. [PMID: 31845968 DOI: 10.1093/femspd/ftz066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 12/16/2019] [Indexed: 11/13/2022] Open
Abstract
The zoonotic disease Q fever caused by the intracellular bacterium Coxiella burnetii remains a global health threat due to its high infectivity, environmental stability, the debilitating nature and the long duration of treatment. Designing new and potent drugs that target previously unexplored pathways is essential to shorten treatment time and minimise antibiotic resistance. Nicotinamide adenine dinucleotide (NAD) is an essential and ubiquitous cofactor in all living organisms. NadB, an L-aspartate oxidase catalysing the first step of the prokaryotic-specific NAD de novo biosynthetic pathway, is required for C. burnetii growth and replication inside host cells. In this study, in vitro enzyme assays utilising recombinant glutathione S-transferase tagged NadB (GST-NadB) demonstrated inhibition of the L-aspartate oxidase activity of NadB by meso-tartrate. Furthermore, meso-tartrate inhibits intracellular growth and replication of C. burnetii inside host cells in a dose-dependent manner, and has no effect on the viability of mammalian cells. Unexpectedly, meso-tartrate also inhibited growth of C. burnetii in axenic medium, and further reduces replication of the nadB mutant inside host cells, suggesting it is acting more widely than simple inhibition of NadB. Overall, these results suggest that the antibacterial activity of meso-tartrate warrants further study, including investigation of its additional target(s).
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Affiliation(s)
- Mebratu A Bitew
- Asia-Pacific Centre for Animal Health, Veterinary Preclinical Centre, Melbourne Veterinary School, The University of Melbourne, Parkville 3010, Victoria, Australia
| | - Nadeeka K Wawegama
- Asia-Pacific Centre for Animal Health, Veterinary Preclinical Centre, Melbourne Veterinary School, The University of Melbourne, Parkville 3010, Victoria, Australia
| | - Hayley J Newton
- Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne 3000, Victoria, Australia
| | - Fiona M Sansom
- Asia-Pacific Centre for Animal Health, Veterinary Preclinical Centre, Melbourne Veterinary School, The University of Melbourne, Parkville 3010, Victoria, Australia
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15
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Abstract
Coxiella burnetii is a unique bacterial pathogen that replicates to high numbers in a lysosome-like intracellular niche. This study identified host proteins that contribute to the pathogen’s capacity to establish this niche and activate the Dot/Icm secretion system required for intracellular replication. Many host proteins were found to contribute to the establishment of C. burnetii virulence by aiding trafficking of the pathogen to the lysosome and creating the degradative lysosome environment. Pathogenic bacteria are able to sense and adapt to their environment by altering their gene expression profile. Here we demonstrated that C. burnetii detects specific amino acids present in the lysosome using a two-component system that up-regulates expression of genes required for Dot/Icm activity. Coxiella burnetii is an intracellular pathogen that replicates in a lysosome-like vacuole through activation of a Dot/Icm-type IVB secretion system and subsequent translocation of effectors that remodel the host cell. Here a genome-wide small interfering RNA screen and reporter assay were used to identify host proteins required for Dot/Icm effector translocation. Significant, and independently validated, hits demonstrated the importance of multiple protein families required for endocytic trafficking of the C. burnetii-containing vacuole to the lysosome. Further analysis demonstrated that the degradative activity of the lysosome created by proteases, such as TPP1, which are transported to the lysosome by receptors, such as M6PR and LRP1, are critical for C. burnetii virulence. Indeed, the C. burnetii PmrA/B regulon, responsible for transcriptional up-regulation of genes encoding the Dot/Icm apparatus and a subset of effectors, induced expression of a virulence-associated transcriptome in response to degradative products of the lysosome. Luciferase reporter strains, and subsequent RNA-sequencing analysis, demonstrated that particular amino acids activate the C. burnetii PmrA/B two-component system. This study has further enhanced our understanding of C. burnetii pathogenesis, the host–pathogen interactions that contribute to bacterial virulence, and the different environmental triggers pathogens can sense to facilitate virulence.
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16
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Siadous FA, Cantet F, Van Schaik E, Burette M, Allombert J, Lakhani A, Bonaventure B, Goujon C, Samuel J, Bonazzi M, Martinez E. Coxiella effector protein CvpF subverts RAB26-dependent autophagy to promote vacuole biogenesis and virulence. Autophagy 2020; 17:706-722. [PMID: 32116095 PMCID: PMC8032239 DOI: 10.1080/15548627.2020.1728098] [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] [Indexed: 11/04/2022] Open
Abstract
Coxiella burnetii, the etiological agent of the zoonosis Q fever, replicates inside host cells within a large vacuole displaying autolysosomal characteristics. The development of this compartment is mediated by bacterial effectors, which interfere with a number of host membrane trafficking pathways. By screening a Coxiella transposon mutant library, we observed that transposon insertions in cbu0626 led to intracellular replication and vacuole biogenesis defects. Here, we demonstrate that CBU0626 is a novel member of the Coxiella vacuolar protein (Cvp) family of effector proteins, which is translocated by the Dot/Icm secretion system and localizes to vesicles with autolysosomal features as well as Coxiella-containing vacuoles (CCVs). We thus renamed this effector CvpF for Coxiella vacuolar protein F. CvpF specifically interacts with the host small GTPase RAB26, leading to the recruitment of the autophagosomal marker MAP1LC3B/LC3B (microtubule associated protein 1 light chain 3 beta) to CCVs. Importantly, cvpF::Tn mutants were highly attenuated compared to wild-type bacteria in the SCID mouse model of infection, highlighting the importance of CvpF for Coxiella virulence. These results suggest that CvpF manipulates endosomal trafficking and macroautophagy/autophagy induction for optimal C. burnetii vacuole biogenesis. Abbreviations: ACCM: acidified citrate cystein medium; AP: adaptor related protein complex; CCV: Coxiella-containing vacuole; Cvp: Coxiella vacuolar protein; GDI: guanosine nucleotide dissociation inhibitor; GDF: GDI dissociation factor; GEF: guanine exchange factor; LAMP1: lysosomal associated membrane protein 1; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MTORC1: mechanistic target of rapamycin kinase MTOR complex 1; PBS: phosphate-buffered saline; PMA: phorbol myristate acetate; SQSTM1/p62: sequestosome 1; WT: wild-type.
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Affiliation(s)
- Fernande Ayenoue Siadous
- Institut de Recherche en Infectiologie de Montpellier (IRIM) UMR 9004 CNRS, Université de Montpellier, Montpellier, France
| | - Franck Cantet
- Institut de Recherche en Infectiologie de Montpellier (IRIM) UMR 9004 CNRS, Université de Montpellier, Montpellier, France
| | - Erin Van Schaik
- Department of Microbial and Molecular Pathogenesis, Texas A&M Health Science Center College of Medicine, Bryan, TX, USA
| | - Mélanie Burette
- Institut de Recherche en Infectiologie de Montpellier (IRIM) UMR 9004 CNRS, Université de Montpellier, Montpellier, France
| | - Julie Allombert
- Institut de Recherche en Infectiologie de Montpellier (IRIM) UMR 9004 CNRS, Université de Montpellier, Montpellier, France
| | - Anissa Lakhani
- Institut de Recherche en Infectiologie de Montpellier (IRIM) UMR 9004 CNRS, Université de Montpellier, Montpellier, France
| | - Boris Bonaventure
- Institut de Recherche en Infectiologie de Montpellier (IRIM) UMR 9004 CNRS, Université de Montpellier, Montpellier, France
| | - Caroline Goujon
- Institut de Recherche en Infectiologie de Montpellier (IRIM) UMR 9004 CNRS, Université de Montpellier, Montpellier, France
| | - James Samuel
- Department of Microbial and Molecular Pathogenesis, Texas A&M Health Science Center College of Medicine, Bryan, TX, USA
| | - Matteo Bonazzi
- Institut de Recherche en Infectiologie de Montpellier (IRIM) UMR 9004 CNRS, Université de Montpellier, Montpellier, France
| | - Eric Martinez
- Institut de Recherche en Infectiologie de Montpellier (IRIM) UMR 9004 CNRS, Université de Montpellier, Montpellier, France
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17
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Bitew MA, Hofmann J, De Souza DP, Wawegama NK, Newton HJ, Sansom FM. SdrA, an NADP(H)-regenerating enzyme, is crucial for Coxiella burnetii to resist oxidative stress and replicate intracellularly. Cell Microbiol 2020; 22:e13154. [PMID: 31872956 DOI: 10.1111/cmi.13154] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 11/24/2019] [Accepted: 12/10/2019] [Indexed: 11/27/2022]
Abstract
Coxiella burnetii, the causative agent of the zoonotic disease Q fever, is a Gram-negative bacterium that replicates inside macrophages within a highly oxidative vacuole. Screening of a transposon mutant library suggested that sdrA, which encodes a putative short-chain dehydrogenase, is required for intracellular replication. Short-chain dehydrogenases are NADP(H)-dependent oxidoreductases, and SdrA contains a predicted NADP+ binding site, suggesting it may facilitate NADP(H) regeneration by C. burnetii, a key process for surviving oxidative stress. Purified recombinant 6×His-SdrA was able to convert NADP+ to NADP(H) in vitro. Mutation to alanine of a conserved glycine residue at position 12 within the predicted NADP binding site abolished significant enzymatic activity. Complementation of the sdrA mutant (sdrA::Tn) with plasmid-expressed SdrA restored intracellular replication to wild-type levels, but expressing enzymatically inactive G12A_SdrA did not. The sdrA::Tn mutant was more susceptible in vitro to oxidative stress, and treating infected host cells with L-ascorbate, an anti-oxidant, partially rescued the intracellular growth defect of sdrA::Tn. Finally, stable isotope labelling studies demonstrated a shift in flux through metabolic pathways in sdrA::Tn consistent with the presence of increased oxidative stress, and host cells infected with sdrA::Tn had elevated levels of reactive oxygen species compared with C. burnetii NMII.
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Affiliation(s)
- Mebratu A Bitew
- Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, The University of Melbourne, Parkville, Australia
| | - Janine Hofmann
- Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, The University of Melbourne, Parkville, Australia
| | - David P De Souza
- Metabolomics Australia, Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, Parkville, Australia
| | - Nadeeka K Wawegama
- Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, The University of Melbourne, Parkville, Australia
| | - Hayley J Newton
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Australia
| | - Fiona M Sansom
- Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, The University of Melbourne, Parkville, Australia
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Ledbetter L, Cherla R, Chambers C, Zhang Y, Zhang G. Eosinophils Affect Antibody Isotype Switching and May Partially Contribute to Early Vaccine-Induced Immunity against Coxiella burnetii. Infect Immun 2019; 87:e00376-19. [PMID: 31427447 PMCID: PMC6803328 DOI: 10.1128/iai.00376-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 08/09/2019] [Indexed: 01/21/2023] Open
Abstract
Coxiella burnetii is an obligate intracellular Gram-negative bacterium which causes human Q fever. An acidified citrate cysteine medium (ACCM-2) has been developed which mimics the intracellular replicative niche of C. burnetii and allows axenic growth of the bacteria. To determine if C. burnetii cultured in ACCM-2 retains immunogenicity, we compared the protective efficacies of formalin-inactivated C. burnetii Nine Mile phase I (PIV) and phase II (PIIV) vaccines derived from axenic culture 7, 14, and 28 days postvaccination. PIV conferred significant protection against virulent C. burnetii as early as 7 days postvaccination, which suggests that ACCM-2-derived PIV retains immunogenicity and protectivity. We analyzed the cellular immune response in spleens from PIV- and PIIV-vaccinated mice by flow cytometry at 7 and 14 days postvaccination and found significantly more granulocytes in PIV-vaccinated mice than in PIIV-vaccinated mice. Interestingly, we found these infiltrating granulocytes to be SSChigh CD11b+ CD125+ Siglec-F+ (where SSChigh indicates a high side scatter phenotype) eosinophils. There was no change in the number of eosinophils in PIV-vaccinated CD4-deficient mice compared to the level in controls, which suggests that eosinophil accumulation is CD4+ T cell dependent. To evaluate the importance of eosinophils in PIV-mediated protection, we vaccinated and challenged eosinophil-deficient ΔdblGATA mice. ΔdblGATA mice had significantly worse disease than their wild-type counterparts when challenged 7 days postvaccination, while no significant difference was seen at 28 days postvaccination. Nevertheless, ΔdblGATA mice had elevated serum IgM with decreased IgG1 and IgG2a whether mice were challenged at 7 or 28 days postvaccination. These results suggest that eosinophils may play a role in early vaccine protection against C. burnetii and contribute to antibody isotype switching.
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Affiliation(s)
- Lindsey Ledbetter
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri, USA
| | - Rama Cherla
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri, USA
| | - Catherine Chambers
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri, USA
| | - Yan Zhang
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri, USA
| | - Guoquan Zhang
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri, USA
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19
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Dresler J, Klimentova J, Pajer P, Salovska B, Fucikova AM, Chmel M, Schmoock G, Neubauer H, Mertens-Scholz K. Quantitative Proteome Profiling of Coxiella burnetii Reveals Major Metabolic and Stress Differences Under Axenic and Cell Culture Cultivation. Front Microbiol 2019; 10:2022. [PMID: 31620097 PMCID: PMC6759588 DOI: 10.3389/fmicb.2019.02022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 08/19/2019] [Indexed: 12/14/2022] Open
Abstract
Coxiella burnetii is the causative agent of the zoonotic disease Q fever. To date, the lipopolysaccharide (LPS) is the only defined and characterized virulence determinant of C. burnetii. In this study, proteome profiles of C. burnetii Nine Mile phase I (RSA 493, NMI) and its isogenic Nine Mile phase II (RSA 439 NMII) isolate with a deep rough LPS were compared on L-929 mouse fibroblasts and in complex (ACCM-2), and defined (ACCM-D) media. Whole proteome extracts were analyzed using a label-free quantification approach. Between 659 and 1,046 C. burnetii proteins of the 2,132 annotated coding sequences (CDS) were identified in any particular experiment. Proteome profiles clustered according to the cultivation conditions used, indicating different regulation patterns. NMI proteome profiles compared to NMII in ACCM-D indicate transition from an exponential to a stationary phase. The levels of regulatory proteins such as RpoS, CsrA2, UspA1, and UspA2 were increased. Comparison of the oxidative stress response of NMI and NMII indicated that ACCM-2 represents a high oxidative stress environment. Expression of peroxidases, superoxide dismutases, as well as thioredoxins was increased for NMI. In contrast, in ACCM-D, only osmoregulation seems to be necessary. Proteome profiles of NMII do not differ and indicate that both axenic media represent similar oxidative stress environments. Deep rough LPS causes changes of the outer membrane stability and fluidity. This might be one reason for the observed differences. Proteins associated with the T4SS and Sec translocon as well as several effector proteins were detectable under all three conditions. Interestingly, none of these putatively secreted proteins are upregulated in ACCM-2 compared to ACCM-D, and L-929 mouse fibroblasts. Curiously, a higher similarity of proteomic patterns (overlapping up- and downregulated proteins) of ACCM-D and bacteria grown in cell culture was observed. Particularly, the proteins involved in a better adaptation or homeostasis in response to the harsh environment of the parasitophorous vacuole were demonstrated for NMI. This semi-quantitative proteomic analysis of C. burnetii compared axenically grown bacteria to those propagated in cell culture.
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Affiliation(s)
| | - Jana Klimentova
- Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czechia
| | - Petr Pajer
- Military Health Institute, Prague, Czechia
| | - Barbora Salovska
- Department of Genome Integrity, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | | | - Martin Chmel
- Department of Infectious Diseases, First Faculty of Medicine, Charles University and Military University Hospital Prague, Prague, Czechia
| | - Gernot Schmoock
- Institute of Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institut, Jena, Germany
| | - Heinrich Neubauer
- Institute of Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institut, Jena, Germany
| | - Katja Mertens-Scholz
- Institute of Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institut, Jena, Germany
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20
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Root A. Do cells use passwords in cell-state transitions? Is cell signaling sometimes encrypted? Theory Biosci 2019; 139:87-93. [PMID: 31175621 DOI: 10.1007/s12064-019-00295-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 06/03/2019] [Indexed: 11/28/2022]
Abstract
Organisms must maintain proper regulation including defense and healing. Life-threatening problems may be caused by pathogens or by a multicellular organism's own cells through cancer or autoimmune disorders. Life evolved solutions to these problems that can be conceptualized through the lens of information security, which is a well-developed field in computer science. Here I argue that taking an information security view of cells is not merely semantics, but useful to explain features of signaling, regulation, and defense. An information security perspective also offers a conduit for cross-fertilization of advanced ideas from computer science and the potential for biology to inform computer science. First, I consider whether cells use passwords, i.e., initiation sequences that are required for subsequent signals to have effects, by analyzing the concept of pioneer transcription factors in chromatin regulation and cellular reprogramming. Second, I consider whether cells may encrypt signal transduction cascades. Encryption could benefit cells by making it more difficult for pathogens or oncogenes to hijack cell networks. By using numerous molecules, cells may gain a security advantage in particular against viruses, whose genome sizes are typically under selection pressure. I provide a simple conceptual argument for how cells may perform encryption through posttranslational modifications, complex formation, and chromatin accessibility. I invoke information theory to provide a criterion of an entropy spike to assess whether a signaling cascade has encryption-like features. I discuss how the frequently invoked concept of context dependency may oversimplify more advanced features of cell signaling networks, such as encryption. Therefore, by considering that biochemical networks may be even more complex than commonly realized we may be better able to understand defenses against pathogens and pathologies.
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Affiliation(s)
- Alex Root
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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21
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Hemsley CM, O’Neill PA, Essex-Lopresti A, Norville IH, Atkins TP, Titball RW. Extensive genome analysis of Coxiella burnetii reveals limited evolution within genomic groups. BMC Genomics 2019; 20:441. [PMID: 31164106 PMCID: PMC6549354 DOI: 10.1186/s12864-019-5833-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 05/23/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Coxiella burnetii is a zoonotic pathogen that resides in wild and domesticated animals across the globe and causes a febrile illness, Q fever, in humans. An improved understanding of the genetic diversity of C. burnetii is essential for the development of diagnostics, vaccines and therapeutics, but genotyping data is lacking from many parts of the world. Sporadic outbreaks of Q fever have occurred in the United Kingdom, but the local genetic make-up of C. burnetii has not been studied in detail. RESULTS Here, we report whole genome data for nine C. burnetii sequences obtained in the UK. All four genomes of C. burnetii from cattle, as well as one sheep sample, belonged to Multi-spacer sequence type (MST) 20, whereas the goat samples were MST33 (three genomes) and MST32 (one genome), two genotypes that have not been described to be present in the UK to date. We established the phylogenetic relationship between the UK genomes and 67 publically available genomes based on single nucleotide polymorphisms (SNPs) in the core genome, which confirmed tight clustering of strains within genomic groups, but also indicated that sub-groups exist within those groups. Variation is mainly achieved through SNPs, many of which are non-synonymous, thereby confirming that evolution of C. burnetii is based on modification of existing genes. Finally, we discovered genomic-group specific genome content, which supports a model of clonal expansion of previously established genotypes, with large scale dissemination of some of these genotypes across continents being observed. CONCLUSIONS The genetic make-up of C. burnetii in the UK is similar to the one in neighboring European countries. As a species, C. burnetii has been considered a clonal pathogen with low genetic diversity at the nucleotide level. Here, we present evidence for significant variation at the protein level between isolates of different genomic groups, which mainly affects secreted and membrane-associated proteins. Our results thereby increase our understanding of the global genetic diversity of C. burnetii and provide new insights into the evolution of this emerging zoonotic pathogen.
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Affiliation(s)
- Claudia M. Hemsley
- College of Life and Environmental Sciences – Biosciences, University of Exeter, Exeter, UK
| | - Paul A. O’Neill
- College of Life and Environmental Sciences – Biosciences, University of Exeter, Exeter, UK
| | | | | | - Tim P. Atkins
- College of Life and Environmental Sciences – Biosciences, University of Exeter, Exeter, UK
- Defence Science and Technology Laboratory, Porton Down, Salisbury, UK
| | - Richard W. Titball
- College of Life and Environmental Sciences – Biosciences, University of Exeter, Exeter, UK
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22
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Sgro GG, Oka GU, Souza DP, Cenens W, Bayer-Santos E, Matsuyama BY, Bueno NF, dos Santos TR, Alvarez-Martinez CE, Salinas RK, Farah CS. Bacteria-Killing Type IV Secretion Systems. Front Microbiol 2019; 10:1078. [PMID: 31164878 PMCID: PMC6536674 DOI: 10.3389/fmicb.2019.01078] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 04/29/2019] [Indexed: 01/25/2023] Open
Abstract
Bacteria have been constantly competing for nutrients and space for billions of years. During this time, they have evolved many different molecular mechanisms by which to secrete proteinaceous effectors in order to manipulate and often kill rival bacterial and eukaryotic cells. These processes often employ large multimeric transmembrane nanomachines that have been classified as types I-IX secretion systems. One of the most evolutionarily versatile are the Type IV secretion systems (T4SSs), which have been shown to be able to secrete macromolecules directly into both eukaryotic and prokaryotic cells. Until recently, examples of T4SS-mediated macromolecule transfer from one bacterium to another was restricted to protein-DNA complexes during bacterial conjugation. This view changed when it was shown by our group that many Xanthomonas species carry a T4SS that is specialized to transfer toxic bacterial effectors into rival bacterial cells, resulting in cell death. This review will focus on this special subtype of T4SS by describing its distinguishing features, similar systems in other proteobacterial genomes, and the nature of the effectors secreted by these systems and their cognate inhibitors.
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Affiliation(s)
- Germán G. Sgro
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Gabriel U. Oka
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Diorge P. Souza
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - William Cenens
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Ethel Bayer-Santos
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Bruno Y. Matsuyama
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Natalia F. Bueno
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | | | - Cristina E. Alvarez-Martinez
- Departamento de Genética, Evolução, Microbiologia e Imunologia, Instituto de Biologia, University of Campinas (UNICAMP), Campinas, Brazil
| | - Roberto K. Salinas
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Chuck S. Farah
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
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23
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Christie PJ, Gomez Valero L, Buchrieser C. Biological Diversity and Evolution of Type IV Secretion Systems. Curr Top Microbiol Immunol 2019; 413:1-30. [PMID: 29536353 PMCID: PMC5912172 DOI: 10.1007/978-3-319-75241-9_1] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The bacterial type IV secretion systems (T4SSs) are a highly functionally and structurally diverse superfamily of secretion systems found in many species of Gram-negative and -positive bacteria. Collectively, the T4SSs can translocate DNA and monomeric and multimeric protein substrates to a variety of bacterial and eukaryotic cell types. Detailed phylogenomics analyses have established that the T4SSs evolved from ancient conjugation machines whose original functions were to disseminate mobile DNA elements within and between bacterial species. How members of the T4SS superfamily evolved to recognize and translocate specific substrate repertoires to prokaryotic or eukaryotic target cells is a fascinating question from evolutionary, biological, and structural perspectives. In this chapter, we will summarize recent findings that have shaped our current view of the biological diversity of the T4SSs. We focus mainly on two subtypes, designated as the types IVA (T4ASS) and IVB (T4BSS) systems that respectively are represented by the paradigmatic Agrobacterium tumefaciens VirB/VirD4 and Legionella pneumophila Dot/Icm T4SSs. We present current information about the composition and architectures of these representative systems. We also describe how these and a few related T4ASS and T4BSS members evolved as specialized nanomachines through acquisition of novel domains or subunits, a process that ultimately generated extensive genetic and structural mosaicism among this secretion superfamily. Finally, we present new phylogenomics information establishing that the T4BSSs are much more broadly distributed than initially envisioned.
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Affiliation(s)
- Peter J Christie
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, TX, 77030, USA.
| | - Laura Gomez Valero
- Institut Pasteur, Biologie des Bactéries Intracellulaires, 75724, Paris, France
- CNRS, UMR 3525, 75724, Paris, France
| | - Carmen Buchrieser
- Institut Pasteur, Biologie des Bactéries Intracellulaires, 75724, Paris, France
- CNRS, UMR 3525, 75724, Paris, France
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Martinez E, Siadous FA, Bonazzi M. Tiny architects: biogenesis of intracellular replicative niches by bacterial pathogens. FEMS Microbiol Rev 2018; 42:425-447. [PMID: 29596635 DOI: 10.1093/femsre/fuy013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 03/26/2018] [Indexed: 11/13/2022] Open
Abstract
Co-evolution of bacterial pathogens with their hosts led to the emergence of a stunning variety of strategies aiming at the evasion of host defences, colonisation of host cells and tissues and, ultimately, the establishment of a successful infection. Pathogenic bacteria are typically classified as extracellular and intracellular; however, intracellular lifestyle comes in many different flavours: some microbes rapidly escape to the cytosol whereas other microbes remain within vacuolar compartments and harness membrane trafficking pathways to generate their host-derived, pathogen-specific replicative niche. Here we review the current knowledge on a variety of vacuolar lifestyles, the effector proteins used by bacteria as tools to take control of the host cell and the main membrane trafficking signalling pathways targeted by vacuolar pathogens as source of membranes and nutrients. Finally, we will also discuss how host cells have developed countermeasures to sense the biogenesis of the aberrant organelles harbouring bacteria. Understanding the dialogue between bacterial and eukaryotic proteins is the key to unravel the molecular mechanisms of infection and in turn, this may lead to the identification of new targets for the development of new antimicrobials.
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Affiliation(s)
- Eric Martinez
- IRIM, University of Montpellier, CNRS, 34293 Montpellier, France
| | | | - Matteo Bonazzi
- IRIM, University of Montpellier, CNRS, 34293 Montpellier, France
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25
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Bitew MA, Khoo CA, Neha N, De Souza DP, Tull D, Wawegama NK, Newton HJ, Sansom FM. De novo NAD synthesis is required for intracellular replication of Coxiella burnetii, the causative agent of the neglected zoonotic disease Q fever. J Biol Chem 2018; 293:18636-18645. [PMID: 30315113 PMCID: PMC6290155 DOI: 10.1074/jbc.ra118.005190] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 10/08/2018] [Indexed: 01/22/2023] Open
Abstract
Coxiella burnetii is an intracellular Gram-negative bacterium responsible for the important zoonotic disease Q fever. Improved genetic tools and the ability to grow this bacterium in host cell-free media has advanced the study of C. burnetii pathogenesis, but the mechanisms that allow it to survive inside the hostile phagolysosome remain incompletely understood. Previous screening of a transposon mutant library for replication within HeLa cells has suggested that nadB, encoding a putative l-aspartate oxidase required for de novo NAD synthesis, is needed for intracellular replication. Here, using genetic complementation of two independent nadB mutants and intracellular replication assays, we confirmed this finding. Untargeted metabolite analyses demonstrated key changes in metabolites in the NAD biosynthetic pathway in the nadB mutant compared with the WT, confirming the involvement of NadB in de novo NAD synthesis. Bioinformatic analysis revealed the presence of a functionally conserved arginine residue at position 275. Using site-directed mutagenesis to substitute this residue with leucine, which abolishes the activity of Escherichia coli NadB, and expression of WT and R275L GST-NadB fusion proteins in E. coli JM109, we found that purified recombinant WT GST-NadB has l-aspartate oxidase activity and that the R275L NadB variant is inactive. Complementation of the C. burnetii nadB mutant with a plasmid expressing this inactive R275L NadB failed to restore replication to WT levels, confirming the link between de novo NAD synthesis and intracellular replication of C. burnetii This suggests that targeting this prokaryotic-specific pathway could advance the development of therapeutics to combat C. burnetii infections.
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Affiliation(s)
- Mebratu A Bitew
- From the Asia-Pacific Centre for Animal Health, Melbourne Veterinary School and
| | - Chen Ai Khoo
- the Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne 3000, Australia
| | - Nitika Neha
- From the Asia-Pacific Centre for Animal Health, Melbourne Veterinary School and
- Metabolomics Australia, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville 3010, Australia and
| | - David P De Souza
- Metabolomics Australia, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville 3010, Australia and
| | - Dedreia Tull
- Metabolomics Australia, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville 3010, Australia and
| | - Nadeeka K Wawegama
- From the Asia-Pacific Centre for Animal Health, Melbourne Veterinary School and
| | - Hayley J Newton
- the Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne 3000, Australia
| | - Fiona M Sansom
- From the Asia-Pacific Centre for Animal Health, Melbourne Veterinary School and
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Crabill E, Schofield WB, Newton HJ, Goodman AL, Roy CR. Dot/Icm-Translocated Proteins Important for Biogenesis of the Coxiella burnetii-Containing Vacuole Identified by Screening of an Effector Mutant Sublibrary. Infect Immun 2018; 86:e00758-17. [PMID: 29339460 PMCID: PMC5865027 DOI: 10.1128/iai.00758-17] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 01/05/2018] [Indexed: 01/25/2023] Open
Abstract
Coxiella burnetii is an intracellular pathogen that replicates in a lysosome-derived vacuole. A determinant necessary for C. burnetii virulence is the Dot/Icm type IVB secretion system (T4SS). The Dot/Icm system delivers more than 100 proteins, called type IV effectors (T4Es), across the vacuolar membrane into the host cell cytosol. Several T4Es have been shown to be important for vacuolar biogenesis. Here, transposon (Tn) insertion sequencing technology (INSeq) was used to identify C. burnetii Nine Mile phase II mutants in an arrayed library, which facilitated the identification and clonal isolation of mutants deficient in 70 different T4E proteins. These effector mutants were screened in HeLa cells for deficiencies in Coxiella-containing vacuole (CCV) biogenesis. This screen identified and validated seven new T4Es that were important for vacuole biogenesis. Loss-of-function mutations in cbu0414 (coxH1), cbu0513, cbu0978 (cem3), cbu1387 (cem6), cbu1524 (caeA), cbu1752, or cbu2028 resulted in a small-vacuole phenotype. These seven mutant strains produced small CCVs in all cells tested, which included macrophage-like cells. The cbu2028::Tn mutant, though unable to develop large CCVs, had intracellular replication rates similar to the rate of the parental strain of C. burnetii, whereas the other six effector mutants defective in CCV biogenesis displayed significant reductions in intracellular replication. Vacuoles created by the cbu0513::Tn mutant did not accumulate lipidated microtubule-associated protein 1A/1B light chain 3 (LC3-II), suggesting a failure in fusion of the CCV with autophagosomes. These seven T4E proteins add to the growing repertoire of C. burnetii factors that contribute to CCV biogenesis.
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Affiliation(s)
- Emerson Crabill
- Department of Microbial Pathogenesis, Yale University School of Medicine, Boyer Center for Molecular Medicine, New Haven, Connecticut, USA
| | - Whitman B Schofield
- Department of Microbial Pathogenesis, Yale University School of Medicine, Boyer Center for Molecular Medicine, New Haven, Connecticut, USA
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, USA
| | - Hayley J Newton
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Andrew L Goodman
- Department of Microbial Pathogenesis, Yale University School of Medicine, Boyer Center for Molecular Medicine, New Haven, Connecticut, USA
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, USA
| | - Craig R Roy
- Department of Microbial Pathogenesis, Yale University School of Medicine, Boyer Center for Molecular Medicine, New Haven, Connecticut, USA
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Coxiella burnetii Inhibits Neutrophil Apoptosis by Exploiting Survival Pathways and Antiapoptotic Protein Mcl-1. Infect Immun 2018; 86:IAI.00504-17. [PMID: 29311244 DOI: 10.1128/iai.00504-17] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 12/18/2017] [Indexed: 12/26/2022] Open
Abstract
Our previous study demonstrated that neutrophils play an important role in host defense against Coxiella burnetii infection in mice. In this study, avirulent strain C. burnetii Nine Mile phase II (NMII) was used to examine if C. burnetii can modulate mouse bone marrow-derived neutrophil apoptosis. The results indicated that NMII can inhibit neutrophil apoptosis. Western blotting demonstrated that caspase-3 cleavage was decreased in NMII-infected neutrophils, while phosphorylated mitogen-activated protein kinase (MAPK) p38 and extracellular signal-regulated kinase 1 (Erk1) were increased. Additionally, p38, Erk1/2, phosphoinositide 3-kinase (PI3K), or NF-κB inhibitors reduced the ability of NMII to inhibit neutrophil apoptosis. These results suggest that NMII-mediated inhibition of neutrophil apoptosis depends on its ability to activate neutrophil MAPK pathways. Antiapoptotic protein myeloid cell leukemia-1 (Mcl-1) was significantly increased in NMII-infected neutrophils, and an Mcl-1 inhibitor significantly reduced the ability of NMII to inhibit neutrophil apoptosis. Mcl-1 protein stability was enhanced by phosphorylation at Thr-163 by Erk, and the protein levels were regulated by p38, Erk, PI3K, and NF-κB. Furthermore, the observation that a type IV secretion system (T4SS)-deficient dotA mutant showed a significantly reduced ability to inhibit neutrophil apoptosis compared to wild-type (WT) NMII suggests that T4SS-secreted factors may be involved in NMII-induced inhibition of neutrophil apoptosis. Collectively, these results demonstrate that NMII inhibits neutrophil apoptosis through inhibition of caspase-3 cleavage and activation of MAPK survival pathways with subsequent expression and stabilization of antiapoptotic protein Mcl-1, a process that may partially require the T4SS.
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Grohmann E, Christie PJ, Waksman G, Backert S. Type IV secretion in Gram-negative and Gram-positive bacteria. Mol Microbiol 2018; 107:455-471. [PMID: 29235173 PMCID: PMC5796862 DOI: 10.1111/mmi.13896] [Citation(s) in RCA: 222] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/07/2017] [Accepted: 12/09/2017] [Indexed: 02/06/2023]
Abstract
Type IV secretion systems (T4SSs) are versatile multiprotein nanomachines spanning the entire cell envelope in Gram-negative and Gram-positive bacteria. They play important roles through the contact-dependent secretion of effector molecules into eukaryotic hosts and conjugative transfer of mobile DNA elements as well as contact-independent exchange of DNA with the extracellular milieu. In the last few years, many details on the molecular mechanisms of T4SSs have been elucidated. Exciting structures of T4SS complexes from Escherichia coli plasmids R388 and pKM101, Helicobacter pylori and Legionella pneumophila have been solved. The structure of the F-pilus was also reported and surprisingly revealed a filament composed of pilin subunits in 1:1 stoichiometry with phospholipid molecules. Many new T4SSs have been identified and characterized, underscoring the structural and functional diversity of this secretion superfamily. Complex regulatory circuits also have been shown to control T4SS machine production in response to host cell physiological status or a quorum of bacterial recipient cells in the vicinity. Here, we summarize recent advances in our knowledge of 'paradigmatic' and emerging systems, and further explore how new basic insights are aiding in the design of strategies aimed at suppressing T4SS functions in bacterial infections and spread of antimicrobial resistances.
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Affiliation(s)
- Elisabeth Grohmann
- Beuth University of Applied Sciences Berlin, Life Sciences and Technology, D-13347 Berlin, Germany
| | - Peter J. Christie
- Department of Microbiology and Molecular Genetics, The University of Texas Medical School at Houston, 6431 Fannin St, Houston, Texas 77030, USA
| | - Gabriel Waksman
- Institute of Structural and Molecular Biology, University College London and Birkbeck College, London WC1E 7HX, United Kingdom
| | - Steffen Backert
- Friedrich Alexander University Erlangen-Nuremberg, Department of Biology, Division of Microbiology, Staudtstrasse 5, D-91058 Erlangen, Germany
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Moura-Martiniano NO, Machado-Ferreira E, Gazêta GS, Soares CAG. Relative transcription of autophagy-related genes in Amblyomma sculptum and Rhipicephalus microplus ticks. EXPERIMENTAL & APPLIED ACAROLOGY 2017; 73:401-428. [PMID: 29181673 DOI: 10.1007/s10493-017-0193-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 11/17/2017] [Indexed: 06/07/2023]
Abstract
Ticks endure stressful off-host periods and perform as vectors of a diversity of infectious agents, thus engaging pathways that expectedly demand for autophagy. Little is known of ticks' autophagy, a conserved eukaryotic machinery assisting in homeostasis processes that also participates in tissue-dependent metabolic functions. Here, the autophagy-related ATG4 (autophagin-1), ATG6 (beclin-1) and ATG8 (LC3) mRNAs from the human diseases vector Amblyomma sculptum and the cattle-tick Rhipicephalus microplus were identified. Comparative qPCR quantifications evidenced different transcriptional status for the ATG genes in the salivary glands (SG), ovaries and intestines of actively feeding ticks. These ATGs had increased relative transcription under nutrient-deprivation, as determined by validation tests with R. microplus embryo-derivative cells BME26 and A. sculptum SG explants incubations in HBSS. Starvation lead to 4-31.8× and ~ 60-500× increments on the ATGs mRNA loads in BME26 and A. sculptum SG explants, respectively. PI3K inhibitor 3MA treatment also affected ATGs expression in BME26. Some ATGs were more transcribed in the SGs than in the ovaries of cattle-ticks. Amblyomma sculptum/R. microplus interspecific comparisons showed that ATG4 and ATG6 were 0.18× less expressed in A. sculptum SGs, but ~ 10-100× more expressed in their ovaries when compared to R. microplus organs. ATG4 and ATG8a transcript loads were ~ 120× and ~ 40× higher, respectively, in A. sculptum intestines when compared to cattle-ticks of similar weight category. ATGs expression in A. sculptum intestines increased with tick weight, indicating Atgs contribution to intracellular blood digestion. Possible roles of the autophagy machinery and their organ-specific expression profile on vector biology are discussed.
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Affiliation(s)
- Nicole O Moura-Martiniano
- Laboratório de Genética Molecular de Eucariontes e Simbiontes, Departamento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Erik Machado-Ferreira
- Laboratório de Genética Molecular de Eucariontes e Simbiontes, Departamento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Gilberto S Gazêta
- Laboratório de Referência Nacional em Vetores das Riquetsioses, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Carlos Augusto Gomes Soares
- Laboratório de Genética Molecular de Eucariontes e Simbiontes, Departamento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
- , Ilha do Fundão, CCS, Bloco A, Lab. A2-120. Rua Professor Rodolpho Paulo Rocco S/N, Rio de Janeiro, RJ, 21941-617, Brazil.
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30
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Díaz S, Rojas ME, Galleguillos M, Maturana C, Smith PI, Cifuentes F, Contreras I, Smith PA. Apoptosis inhibition of Atlantic salmon (Salmo salar) peritoneal macrophages by Piscirickettsia salmonis. JOURNAL OF FISH DISEASES 2017; 40:1895-1902. [PMID: 28699666 DOI: 10.1111/jfd.12660] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Revised: 04/27/2017] [Accepted: 04/30/2017] [Indexed: 06/07/2023]
Abstract
To improve the understanding of the piscirickettsiosis pathogenesis, the in vivo apoptosis modulation of peritoneal macrophages and lymphocytes was studied in juvenile Salmo salar intraperitoneally injected with Piscirickettsia salmonis. Five fish were sampled at post-exposure days 1, 5, 8 (preclinical), 20 (clinical) and 40 (post-clinical period of the disease), and the leucocytes of their coelomic washings were analysed by flow cytometry (using the JC-1 cationic dye), TUNEL and cytology to detect apoptotic cells. A selective and temporal pattern of apoptosis modulation by P. salmonis infection was observed. Apoptosis in lymphocytes was not affected, whereas it was inhibited in macrophages but only during the preclinical stage of the induced piscirickettsiosis. Hence, it is postulated that P. salmonis inhibits macrophage apoptosis at the beginning of the disease development to survive, multiply and probably be transported inside these phagocytes; once this process is complete, macrophage apoptosis is no longer inhibited, thus facilitating the exit of the bacteria from the infected cells for continuing their life cycle.
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Affiliation(s)
- S Díaz
- Facultad de Ciencias Veterinarias, Universidad de Chile, Santiago, Chile
| | - M E Rojas
- Facultad de Ciencias Veterinarias, Universidad de Chile, Santiago, Chile
| | - M Galleguillos
- Facultad de Ciencias Veterinarias, Universidad de Chile, Santiago, Chile
| | | | - P I Smith
- Universidad del Desarrollo, Santiago, Chile
| | - F Cifuentes
- Facultad de Ciencias Veterinarias, Universidad de Chile, Santiago, Chile
| | | | - P A Smith
- Facultad de Ciencias Veterinarias, Universidad de Chile, Santiago, Chile
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Wallqvist A, Wang H, Zavaljevski N, Memišević V, Kwon K, Pieper R, Rajagopala SV, Reifman J. Mechanisms of action of Coxiella burnetii effectors inferred from host-pathogen protein interactions. PLoS One 2017; 12:e0188071. [PMID: 29176882 PMCID: PMC5703456 DOI: 10.1371/journal.pone.0188071] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 10/31/2017] [Indexed: 02/06/2023] Open
Abstract
Coxiella burnetii is an obligate Gram-negative intracellular pathogen and the etiological agent of Q fever. Successful infection requires a functional Type IV secretion system, which translocates more than 100 effector proteins into the host cytosol to establish the infection, restructure the intracellular host environment, and create a parasitophorous vacuole where the replicating bacteria reside. We used yeast two-hybrid (Y2H) screening of 33 selected C. burnetii effectors against whole genome human and murine proteome libraries to generate a map of potential host-pathogen protein-protein interactions (PPIs). We detected 273 unique interactions between 20 pathogen and 247 human proteins, and 157 between 17 pathogen and 137 murine proteins. We used orthology to combine the data and create a single host-pathogen interaction network containing 415 unique interactions between 25 C. burnetii and 363 human proteins. We further performed complementary pairwise Y2H testing of 43 out of 91 C. burnetii-human interactions involving five pathogen proteins. We used the combined data to 1) perform enrichment analyses of target host cellular processes and pathways, 2) examine effectors with known infection phenotypes, and 3) infer potential mechanisms of action for four effectors with uncharacterized functions. The host-pathogen interaction profiles supported known Coxiella phenotypes, such as adapting cell morphology through cytoskeletal re-arrangements, protein processing and trafficking, organelle generation, cholesterol processing, innate immune modulation, and interactions with the ubiquitin and proteasome pathways. The generated dataset of PPIs-the largest collection of unbiased Coxiella host-pathogen interactions to date-represents a rich source of information with respect to secreted pathogen effector proteins and their interactions with human host proteins.
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Affiliation(s)
- Anders Wallqvist
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Fort Detrick, Maryland, United States of America
| | - Hao Wang
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Fort Detrick, Maryland, United States of America
| | - Nela Zavaljevski
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Fort Detrick, Maryland, United States of America
| | - Vesna Memišević
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Fort Detrick, Maryland, United States of America
| | - Keehwan Kwon
- J. Craig Venter Institute, Rockville, Maryland, United States of America
| | - Rembert Pieper
- J. Craig Venter Institute, Rockville, Maryland, United States of America
| | | | - Jaques Reifman
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Fort Detrick, Maryland, United States of America
- * E-mail:
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32
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Sil P, Muse G, Martinez J. A ravenous defense: canonical and non-canonical autophagy in immunity. Curr Opin Immunol 2017; 50:21-31. [PMID: 29125936 DOI: 10.1016/j.coi.2017.10.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 10/04/2017] [Indexed: 12/29/2022]
Abstract
While classically considered a survival mechanism employed during nutrient scarcity, the autophagy pathway operates in multiple scenarios wherein a return to homeostasis or degradative removal of an invader is required. Now recognized as a pathway with vast immunoregulatory power, autophagy can no longer serve as a 'one size fits all' term, as its machinery can be recruited to different pathogens, at different times, with different outcomes. Both canonical autophagy and the molecularly related, yet divergent pathways non-canonical autophagy are key players in proper host defense and allow us an opportunity to tailor infectious disease intervention and treatment to its specific pathway.
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Affiliation(s)
- Payel Sil
- Immunity, Inflammation, and Disease Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Ginger Muse
- Immunity, Inflammation, and Disease Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Jennifer Martinez
- Immunity, Inflammation, and Disease Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, NC 27709, USA.
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Häuslein I, Cantet F, Reschke S, Chen F, Bonazzi M, Eisenreich W. Multiple Substrate Usage of Coxiella burnetii to Feed a Bipartite Metabolic Network. Front Cell Infect Microbiol 2017; 7:285. [PMID: 28706879 PMCID: PMC5489692 DOI: 10.3389/fcimb.2017.00285] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 06/12/2017] [Indexed: 12/24/2022] Open
Abstract
The human pathogen Coxiella burnetii causes Q-fever and is classified as a category B bio-weapon. Exploiting the development of the axenic growth medium ACCM-2, we have now used 13C-labeling experiments and isotopolog profiling to investigate the highly diverse metabolic network of C. burnetii. To this aim, C. burnetii RSA 439 NMII was cultured in ACCM-2 containing 5 mM of either [U-13C3]serine, [U-13C6]glucose, or [U-13C3]glycerol until the late-logarithmic phase. GC/MS-based isotopolog profiling of protein-derived amino acids, methanol-soluble polar metabolites, fatty acids, and cell wall components (e.g., diaminopimelate and sugars) from the labeled bacteria revealed differential incorporation rates and isotopolog profiles. These data served to decipher the diverse usages of the labeled substrates and the relative carbon fluxes into the core metabolism of the pathogen. Whereas, de novo biosynthesis from any of these substrates could not be found for histidine, isoleucine, leucine, lysine, phenylalanine, proline and valine, the other amino acids and metabolites under study acquired 13C-label at specific rates depending on the nature of the tracer compound. Glucose was directly used for cell wall biosynthesis, but was also converted into pyruvate (and its downstream metabolites) through the glycolytic pathway or into erythrose 4-phosphate (e.g., for the biosynthesis of tyrosine) via the non-oxidative pentose phosphate pathway. Glycerol efficiently served as a gluconeogenetic substrate and could also be used via phosphoenolpyruvate and diaminopimelate as a major carbon source for cell wall biosynthesis. In contrast, exogenous serine was mainly utilized in downstream metabolic processes, e.g., via acetyl-CoA in a complete citrate cycle with fluxes in the oxidative direction and as a carbon feed for fatty acid biosynthesis. In summary, the data reflect multiple and differential substrate usages by C. burnetii in a bipartite-type metabolic network, resembling the overall topology of the related pathogen Legionella pneumophila. These strategies could benefit the metabolic capacities of the pathogens also as a trait to adapt for replication under intracellular conditions.
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Affiliation(s)
- Ina Häuslein
- Department of Chemistry, Chair of Biochemistry, Technische Universität MünchenGarching, Germany
| | - Franck Cantet
- IRIM-UMR 9004, Infectious Disease Research Institute of Montpellier, Université de Montpellier, Centre National de la Recherche ScientifiqueMontpellier, France
| | - Sarah Reschke
- Department of Chemistry, Chair of Biochemistry, Technische Universität MünchenGarching, Germany
| | - Fan Chen
- Department of Chemistry, Chair of Biochemistry, Technische Universität MünchenGarching, Germany
| | - Matteo Bonazzi
- IRIM-UMR 9004, Infectious Disease Research Institute of Montpellier, Université de Montpellier, Centre National de la Recherche ScientifiqueMontpellier, France
| | - Wolfgang Eisenreich
- Department of Chemistry, Chair of Biochemistry, Technische Universität MünchenGarching, Germany
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Host and Bacterial Factors Control Susceptibility of Drosophila melanogaster to Coxiella burnetii Infection. Infect Immun 2017; 85:IAI.00218-17. [PMID: 28438980 DOI: 10.1128/iai.00218-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 04/17/2017] [Indexed: 12/12/2022] Open
Abstract
Coxiella burnetii is the causative agent of Q fever, a zoonotic disease that threatens both human and animal health. Due to the paucity of experimental animal models, little is known about how host factors interface with bacterial components and affect pathogenesis. Here, we used Drosophila melanogaster, in conjunction with the biosafety level 2 (BSL2) Nine Mile phase II (NMII) clone 4 strain of C. burnetii, as a model to investigate host and bacterial components implicated in infection. We demonstrate that adult Drosophila flies are susceptible to C. burnetii NMII infection and that this bacterial strain, which activates the immune deficiency (IMD) pathway, is able to replicate and cause mortality in the animals. We show that in the absence of Eiger, the only known tumor necrosis factor (TNF) superfamily homolog in Drosophila, Coxiella-infected flies exhibit reduced mortality from infection. We also demonstrate that the Coxiella type 4 secretion system (T4SS) is critical for the formation of the Coxiella-containing vacuole and establishment of infection in Drosophila Altogether, our data reveal that the Drosophila TNF homolog Eiger and the Coxiella T4SS are implicated in the pathogenesis of C. burnetii in flies. The Drosophila/NMII model mimics relevant aspects of the infection in mammals, such as a critical role of host TNF and the bacterial T4SS in pathogenesis. Our work also demonstrates the usefulness of this BSL2 model to investigate both host and Coxiella components implicated in infection.
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Abstract
It is estimated that approximately one billion people are at risk of infection with obligate intracellular bacteria, but little is known about the underlying mechanisms that govern their life cycles. The difficulty in studying Chlamydia spp., Coxiella spp., Rickettsia spp., Anaplasma spp., Ehrlichia spp. and Orientia spp. is, in part, due to their genetic intractability. Recently, genetic tools have been developed; however, optimizing the genomic manipulation of obligate intracellular bacteria remains challenging. In this Review, we describe the progress in, as well as the constraints that hinder, the systematic development of a genetic toolbox for obligate intracellular bacteria. We highlight how the use of genetically manipulated pathogens has facilitated a better understanding of microbial pathogenesis and immunity, and how the engineering of obligate intracellular bacteria could enable the discovery of novel signalling circuits in host-pathogen interactions.
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Samanta D, Mulye M, Clemente TM, Justis AV, Gilk SD. Manipulation of Host Cholesterol by Obligate Intracellular Bacteria. Front Cell Infect Microbiol 2017; 7:165. [PMID: 28529926 PMCID: PMC5418226 DOI: 10.3389/fcimb.2017.00165] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 04/18/2017] [Indexed: 12/29/2022] Open
Abstract
Cholesterol is a multifunctional lipid that plays important metabolic and structural roles in the eukaryotic cell. Despite having diverse lifestyles, the obligate intracellular bacterial pathogens Chlamydia, Coxiella, Anaplasma, Ehrlichia, and Rickettsia all target cholesterol during host cell colonization as a potential source of membrane, as well as a means to manipulate host cell signaling and trafficking. To promote host cell entry, these pathogens utilize cholesterol-rich microdomains known as lipid rafts, which serve as organizational and functional platforms for host signaling pathways involved in phagocytosis. Once a pathogen gains entrance to the intracellular space, it can manipulate host cholesterol trafficking pathways to access nutrient-rich vesicles or acquire membrane components for the bacteria or bacteria-containing vacuole. To acquire cholesterol, these pathogens specifically target host cholesterol metabolism, uptake, efflux, and storage. In this review, we examine the strategies obligate intracellular bacterial pathogens employ to manipulate cholesterol during host cell colonization. Understanding how obligate intracellular pathogens target and use host cholesterol provides critical insight into the host-pathogen relationship.
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Affiliation(s)
- Dhritiman Samanta
- Department of Microbiology and Immunology, Indiana University School of MedicineIndianapolis, IN, USA
| | - Minal Mulye
- Department of Microbiology and Immunology, Indiana University School of MedicineIndianapolis, IN, USA
| | - Tatiana M Clemente
- Department of Microbiology and Immunology, Indiana University School of MedicineIndianapolis, IN, USA
| | - Anna V Justis
- Department of Microbiology and Immunology, Indiana University School of MedicineIndianapolis, IN, USA
| | - Stacey D Gilk
- Department of Microbiology and Immunology, Indiana University School of MedicineIndianapolis, IN, USA
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A Farnesylated Coxiella burnetii Effector Forms a Multimeric Complex at the Mitochondrial Outer Membrane during Infection. Infect Immun 2017; 85:IAI.01046-16. [PMID: 28242621 DOI: 10.1128/iai.01046-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 02/17/2017] [Indexed: 01/16/2023] Open
Abstract
Coxiella burnetii, the causative agent of Q fever, establishes a unique lysosome-derived intracellular niche termed the Coxiella-containing vacuole (CCV). The Dot/Icm-type IVB secretion system is essential for the biogenesis of the CCV and the intracellular replication of Coxiella Effector proteins, translocated into the host cell through this apparatus, act to modulate host trafficking and signaling processes to facilitate CCV development. Here we investigated the role of CBU0077, a conserved Coxiella effector that had previously been observed to localize to lysosomal membranes. CBU0077 was dispensable for the intracellular replication of Coxiella in HeLa and THP-1 cells and did not appear to participate in CCV biogenesis. Intriguingly, native and epitope-tagged CBU0077 produced by Coxiella displayed specific punctate localization at host cell mitochondria. As such, we designated CBU0077 MceA (mitochondrial Coxiellaeffector protein A). Analysis of ectopically expressed MceA truncations revealed that the capacity to traffic to mitochondria is encoded within the first 84 amino acids of this protein. MceA is farnesylated by the host cell; however, this does not impact mitochondrial localization. Examination of mitochondria isolated from infected cells revealed that MceA is specifically integrated into the mitochondrial outer membrane and forms a complex of approximately 120 kDa. Engineering Coxiella to express either MceA tagged with 3×FLAG or MceA tagged with 2×hemagglutinin allowed us to perform immunoprecipitation experiments that showed that MceA forms a homo-oligomeric species at the mitochondrial outer membrane during infection. This research reveals that mitochondria are a bona fide target of Coxiella effectors and MceA is a complex-forming effector at the mitochondrial outer membrane during Coxiella infection.
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Noroy C, Meyer DF. Comparative Genomics of the Zoonotic Pathogen Ehrlichia chaffeensis Reveals Candidate Type IV Effectors and Putative Host Cell Targets. Front Cell Infect Microbiol 2017; 6:204. [PMID: 28180111 PMCID: PMC5263134 DOI: 10.3389/fcimb.2016.00204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 12/21/2016] [Indexed: 12/04/2022] Open
Abstract
During infection, some intracellular pathogenic bacteria use a dedicated multiprotein complex known as the type IV secretion system to deliver type IV effector (T4E) proteins inside the host cell. These T4Es allow the bacteria to evade host defenses and to subvert host cell processes to their own advantage. Ehrlichia chaffeensis is a tick-transmitted obligate intracellular pathogenic bacterium, which causes human monocytic ehrlichiosis. Using comparative whole genome analysis, we identified the relationship between eight available E. chaffeensis genomes isolated from humans and show that these genomes are highly conserved. We identified the candidate core type IV effectome of E. chaffeensis and some conserved intracellular adaptive strategies. We assigned the West Paces strain to genetic group II and predicted the repertoires of T4Es encoded by E. chaffeensis genomes, as well as some putative host cell targets. We demonstrated that predicted T4Es are preferentially distributed in gene sparse regions of the genome. In addition to the identification of the two known type IV effectors of Anaplasmataceae, we identified two novel candidates T4Es, ECHLIB_RS02720 and ECHLIB_RS04640, which are not present in all E. chaffeensis strains and could explain some variations in inter-strain virulence. We also identified another novel candidate T4E, ECHLIB_RS02720, a hypothetical protein exhibiting EPIYA, and NLS domains as well as a classical type IV secretion signal, suggesting an important role inside the host cell. Overall, our results agree with current knowledge of Ehrlichia molecular pathogenesis, and reveal novel candidate T4Es that require experimental validation. This work demonstrates that comparative effectomics enables identification of important host pathways targeted by the bacterial pathogen. Our study, which focuses on the type IV effector repertoires among several strains of E. chaffeensis species, is an original approach and provides rational putative targets for the design of alternative therapeutics against intracellular pathogens. The collection of putative effectors of E. chaffeensis described in our paper could serve as a roadmap for future studies of the function and evolution of effectors.
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Affiliation(s)
- Christophe Noroy
- CIRAD, UMR ASTREGuadeloupe, France; INRA, UMR 1309 ASTREMontpellier, France; Université des AntillesGuadeloupe, France
| | - Damien F Meyer
- CIRAD, UMR ASTREGuadeloupe, France; INRA, UMR 1309 ASTREMontpellier, France
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Hijacking of Membrane Contact Sites by Intracellular Bacterial Pathogens. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 997:211-223. [DOI: 10.1007/978-981-10-4567-7_16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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41
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Hocke AC, Suttorp N, Hippenstiel S. Human lung ex vivo infection models. Cell Tissue Res 2016; 367:511-524. [PMID: 27999962 PMCID: PMC7087833 DOI: 10.1007/s00441-016-2546-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 11/24/2016] [Indexed: 12/21/2022]
Abstract
Pneumonia is counted among the leading causes of death worldwide. Viruses, bacteria and pathogen-related molecules interact with cells present in the human alveolus by numerous, yet poorly understood ways. Traditional cell culture models little reflect the cellular composition, matrix complexity and three-dimensional architecture of the human lung. Integrative animal models suffer from species differences, which are of particular importance for the investigation of zoonotic lung diseases. The use of cultured ex vivo infected human lung tissue may overcome some of these limitations and complement traditional models. The present review gives an overview of common bacterial lung infections, such as pneumococcal infection and of widely neglected pathogens modeled in ex vivo infected lung tissue. The role of ex vivo infected lung tissue for the investigation of emerging viral zoonosis including influenza A virus and Middle East respiratory syndrome coronavirus is discussed. Finally, further directions for the elaboration of such models are revealed. Overall, the introduced models represent meaningful and robust methods to investigate principles of pathogen-host interaction in original human lung tissue.
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Affiliation(s)
- Andreas C Hocke
- Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Norbert Suttorp
- Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Stefan Hippenstiel
- Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany.
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Murine Alveolar Macrophages Are Highly Susceptible to Replication of Coxiella burnetii Phase II In Vitro. Infect Immun 2016; 84:2439-48. [PMID: 27297388 DOI: 10.1128/iai.00411-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 06/07/2016] [Indexed: 12/18/2022] Open
Abstract
Coxiella burnetii is a Gram-negative bacterium that causes Q fever in humans. Q fever is an atypical pneumonia transmitted through inhalation of contaminated aerosols. In mammalian lungs, C. burnetii infects and replicates in several cell types, including alveolar macrophages (AMs). The innate immunity and signaling pathways operating during infection are still poorly understood, in part because of the lack of relevant host cell models for infection in vitro In the study described here, we investigated and characterized the infection of primary murine AMs by C. burnetii phase II in vitro Our data reveal that AMs show a pronounced M2 polarization and are highly permissive to C. burnetii multiplication in vitro Murine AMs present an increased susceptibility to infection in comparison to primary bone marrow-derived macrophages. AMs support more than 2 logs of bacterial replication during 12 days of infection in culture, similar to highly susceptible host cells, such as Vero and THP-1 cells. As a proof of principle that AMs are useful for investigation of C. burnetii replication, we performed experiments with AMs from Nos2(-/-) or Ifng(-/-) mice. In the absence of gamma interferon and nitric oxide synthase 2 (NOS2), AMs were significantly more permissive than wild-type cells. In contrast, AMs from Il4(-/-) mice were more restrictive to C. burnetii replication, supporting the importance of M2 polarization for the permissiveness of AMs to C. burnetii replication. Collectively, our data account for understanding the high susceptibility of alveolar macrophages to bacterial replication and support the use of AMs as a relevant model of C. burnetii growth in primary macrophages.
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Fielden LF, Kang Y, Newton HJ, Stojanovski D. Targeting mitochondria: how intravacuolar bacterial pathogens manipulate mitochondria. Cell Tissue Res 2016; 367:141-154. [PMID: 27515462 DOI: 10.1007/s00441-016-2475-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Accepted: 07/07/2016] [Indexed: 02/07/2023]
Abstract
Manipulation of host cell function by bacterial pathogens is paramount for successful invasion and creation of a niche conducive to bacterial replication. Mitochondria play a role in many important cellular processes including energy production, cellular calcium homeostasis, lipid metabolism, haeme biosynthesis, immune signalling and apoptosis. The sophisticated integration of host cell processes by the mitochondrion have seen it emerge as a key target during bacterial infection of human host cells. This review highlights the targeting and interaction of this dynamic organelle by intravacuolar bacterial pathogens and the way that the modulation of mitochondrial function might contribute to pathogenesis.
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Affiliation(s)
- Laura F Fielden
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Yilin Kang
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Hayley J Newton
- Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Parkville, VIC, 3000, Australia.
| | - Diana Stojanovski
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, 3010, Australia.
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44
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Justis AV, Hansen B, Beare PA, King KB, Heinzen RA, Gilk SD. Interactions between the Coxiella burnetii parasitophorous vacuole and the endoplasmic reticulum involve the host protein ORP1L. Cell Microbiol 2016; 19. [PMID: 27345457 DOI: 10.1111/cmi.12637] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 06/06/2016] [Accepted: 06/17/2016] [Indexed: 01/07/2023]
Abstract
Coxiella burnetii is a gram-negative intracellular bacterium that forms a large, lysosome-like parasitophorous vacuole (PV) essential for bacterial replication. Host membrane lipids are critical for the formation and maintenance of this intracellular niche, yet the mechanisms by which Coxiella manipulates host cell lipid metabolism, trafficking and signalling are unknown. Oxysterol-binding protein-related protein 1 long (ORP1L) is a mammalian lipid-binding protein that plays a dual role in cholesterol-dependent endocytic trafficking as well as interactions between endosomes and the endoplasmic reticulum (ER). We found that ORP1L localized to the Coxiella PV within 12 h of infection through a process requiring the Coxiella Dot/Icm Type 4B secretion system, which secretes effector proteins into the host cell cytoplasm where they manipulate trafficking and signalling pathways. The ORP1L N-terminal ankyrin repeats were necessary and sufficient for PV localization, indicating that ORP1L binds a PV membrane protein. Strikingly, ORP1L simultaneously co-localized with the PV and ER, and electron microscopy revealed membrane contact sites between the PV and ER membranes. In ORP1L-depleted cells, PVs were significantly smaller than PVs from control cells. These data suggest that ORP1L is specifically recruited by the bacteria to the Coxiella PV, where it influences PV membrane dynamics and interactions with the ER.
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Affiliation(s)
- Anna V Justis
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Bryan Hansen
- Research Technology Branch, National Institutes of Health, Hamilton, MT, USA
| | - Paul A Beare
- Laboratory of Bacteriology, Rocky Mountain Labs, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Kourtney B King
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Robert A Heinzen
- Laboratory of Bacteriology, Rocky Mountain Labs, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Stacey D Gilk
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA
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Gonzalez-Rivera C, Bhatty M, Christie PJ. Mechanism and Function of Type IV Secretion During Infection of the Human Host. Microbiol Spectr 2016; 4:10.1128/microbiolspec.VMBF-0024-2015. [PMID: 27337453 PMCID: PMC4920089 DOI: 10.1128/microbiolspec.vmbf-0024-2015] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Indexed: 02/07/2023] Open
Abstract
Bacterial pathogens employ type IV secretion systems (T4SSs) for various purposes to aid in survival and proliferation in eukaryotic hosts. One large T4SS subfamily, the conjugation systems, confers a selective advantage to the invading pathogen in clinical settings through dissemination of antibiotic resistance genes and virulence traits. Besides their intrinsic importance as principle contributors to the emergence of multiply drug-resistant "superbugs," detailed studies of these highly tractable systems have generated important new insights into the mode of action and architectures of paradigmatic T4SSs as a foundation for future efforts aimed at suppressing T4SS machine function. Over the past decade, extensive work on the second large T4SS subfamily, the effector translocators, has identified a myriad of mechanisms employed by pathogens to subvert, subdue, or bypass cellular processes and signaling pathways of the host cell. An overarching theme in the evolution of many effectors is that of molecular mimicry. These effectors carry domains similar to those of eukaryotic proteins and exert their effects through stealthy interdigitation of cellular pathways, often with the outcome not of inducing irreversible cell damage but rather of reversibly modulating cellular functions. This article summarizes the major developments for the actively studied pathogens with an emphasis on the structural and functional diversity of the T4SSs and the emerging common themes surrounding effector function in the human host.
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Affiliation(s)
- Christian Gonzalez-Rivera
- Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin St, Houston, Texas 77030, Phone: 713-500-5440 (P. J. Christie); 713-500-5441 (C. Gonzalez-Rivera, M. Bhatty)
| | - Minny Bhatty
- Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin St, Houston, Texas 77030, Phone: 713-500-5440 (P. J. Christie); 713-500-5441 (C. Gonzalez-Rivera, M. Bhatty)
| | - Peter J. Christie
- Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin St, Houston, Texas 77030, Phone: 713-500-5440 (P. J. Christie); 713-500-5441 (C. Gonzalez-Rivera, M. Bhatty)
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46
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Coxiella burnetii effector CvpB modulates phosphoinositide metabolism for optimal vacuole development. Proc Natl Acad Sci U S A 2016; 113:E3260-9. [PMID: 27226300 DOI: 10.1073/pnas.1522811113] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The Q fever bacterium Coxiella burnetii replicates inside host cells within a large Coxiella-containing vacuole (CCV) whose biogenesis relies on the Dot/Icm-dependent secretion of bacterial effectors. Several membrane trafficking pathways contribute membranes, proteins, and lipids for CCV biogenesis. These include the endocytic and autophagy pathways, which are characterized by phosphatidylinositol 3-phosphate [PI(3)P]-positive membranes. Here we show that the C. burnetii secreted effector Coxiella vacuolar protein B (CvpB) binds PI(3)P and phosphatidylserine (PS) on CCVs and early endosomal compartments and perturbs the activity of the phosphatidylinositol 5-kinase PIKfyve to manipulate PI(3)P metabolism. CvpB association to early endosome triggers vacuolation and clustering, leading to the channeling of large PI(3)P-positive membranes to CCVs for vacuole expansion. At CCVs, CvpB binding to early endosome- and autophagy-derived PI(3)P and the concomitant inhibition of PIKfyve favor the association of the autophagosomal machinery to CCVs for optimal homotypic fusion of the Coxiella-containing compartments. The importance of manipulating PI(3)P metabolism is highlighted by mutations in cvpB resulting in a multivacuolar phenotype, rescuable by gene complementation, indicative of a defect in CCV biogenesis. Using the insect model Galleria mellonella, we demonstrate the in vivo relevance of defective CCV biogenesis by highlighting an attenuated virulence phenotype associated with cvpB mutations.
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47
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Raghavan R. A repeat motif on a Coxiella effector protein facilitates apoptosis inhibition. Virulence 2016; 7:369-71. [PMID: 26949987 DOI: 10.1080/21505594.2016.1156834] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Affiliation(s)
- Rahul Raghavan
- a Department of Biology and Center for Life in Extreme Environments , Portland State University , Portland , OR , USA
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48
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Rab GTPases and the Autophagy Pathway: Bacterial Targets for a Suitable Biogenesis and Trafficking of Their Own Vacuoles. Cells 2016; 5:cells5010011. [PMID: 27005665 PMCID: PMC4810096 DOI: 10.3390/cells5010011] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 03/02/2016] [Accepted: 03/03/2016] [Indexed: 12/18/2022] Open
Abstract
Autophagy is an intracellular process that comprises degradation of damaged organelles, protein aggregates and intracellular pathogens, having an important role in controlling the fate of invading microorganisms. Intracellular pathogens are internalized by professional and non-professional phagocytes, localizing in compartments called phagosomes. To degrade the internalized microorganism, the microbial phagosome matures by fusion events with early and late endosomal compartments and lysosomes, a process that is regulated by Rab GTPases. Interestingly, in order to survive and replicate in the phagosome, some pathogens employ different strategies to manipulate vesicular traffic, inhibiting phagolysosomal biogenesis (e.g., Staphylococcus aureus and Mycobacterium tuberculosis) or surviving in acidic compartments and forming replicative vacuoles (e.g., Coxiellaburnetti and Legionella pneumophila). The bacteria described in this review often use secretion systems to control the host’s response and thus disseminate. To date, eight types of secretion systems (Type I to Type VIII) are known. Some of these systems are used by bacteria to translocate pathogenic proteins into the host cell and regulate replicative vacuole formation, apoptosis, cytokine responses, and autophagy. Herein, we have focused on how bacteria manipulate small Rab GTPases to control many of these processes. The growing knowledge in this field may facilitate the development of new treatments or contribute to the prevention of these types of bacterial infections.
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Schulze-Luehrmann J, Eckart RA, Ölke M, Saftig P, Liebler-Tenorio E, Lührmann A. LAMP proteins account for the maturation delay during the establishment of the Coxiella burnetii-containing vacuole. Cell Microbiol 2016; 18:181-94. [PMID: 26249821 DOI: 10.1111/cmi.12494] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 07/21/2015] [Accepted: 07/21/2015] [Indexed: 12/28/2022]
Abstract
The obligate intracellular pathogen Coxiella burnetii replicates in a large phagolysosomal-like vacuole. Currently, both host and bacterial factors required for creating this replicative parasitophorous C. burnetii-containing vacuole (PV) are poorly defined. Here, we assessed the contributions of the most abundant proteins of the lysosomal membrane, LAMP-1 and LAMP-2, to the establishment and maintenance of the PV. Whereas these proteins were not critical for uptake of C. burnetii, they influenced the intracellular replication of C. burnetii. In LAMP-1/2 double-deficient fibroblasts as well as in LAMP-1/2 knock-down cells, C. burnetii establishes a significantly smaller, yet faster maturing vacuole, which harboured more bacteria. The accelerated maturation of PVs in LAMP double-deficient fibroblasts, which was partially or fully reversed by ectopic expression of LAMP-1 or LAMP-2, respectively, was characterized by an increased fusion rate with endosomes, lysosomes and bead-containing phagosomes, but not by different fusion kinetics with autophagy vesicles. These findings establish that LAMP proteins are critical for the maturation delay of PVs. Unexpectedly, neither the creation of the spacious vacuole nor the delay in maturation was found to be prerequisites for the intracellular replication of C. burnetii.
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Affiliation(s)
- Jan Schulze-Luehrmann
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander Universität (FAU) Erlangen-Nürnberg, Germany
| | - Rita A Eckart
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander Universität (FAU) Erlangen-Nürnberg, Germany
| | - Martha Ölke
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander Universität (FAU) Erlangen-Nürnberg, Germany
| | - Paul Saftig
- Biochemical Institute, Christian Albrechts University of Kiel, Kiel, Germany
| | | | - Anja Lührmann
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander Universität (FAU) Erlangen-Nürnberg, Germany
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50
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Bisle S, Klingenbeck L, Borges V, Sobotta K, Schulze-Luehrmann J, Menge C, Heydel C, Gomes JP, Lührmann A. The inhibition of the apoptosis pathway by the Coxiella burnetii effector protein CaeA requires the EK repetition motif, but is independent of survivin. Virulence 2016; 7:400-12. [PMID: 26760129 DOI: 10.1080/21505594.2016.1139280] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
ABSRTACT Coxiella burnetii is an obligate intracellular bacterium that causes Query (Q) fever, a zoonotic disease. It requires a functional type IV secretion system (T4SS) which translocate bacterial effector proteins into the host cell cytoplasm and thereby facilitates bacterial replication. To date, more than 130 effector proteins have been identified, but their functions remain largely unknown. Recently, we demonstrated that one of these proteins, CaeA (CBU1524) localized to the host cell nucleus and inhibited intrinsic apoptosis of HEK293 or CHO cells. In the present study we addressed the question whether CaeA also affects the extrinsic apoptosis pathway. Ectopic expression of CaeA reduced extrinsic apoptosis and prevented the cleavage of the executioner caspase 7, but did not impair the activation of initiator caspase 9. CaeA expression resulted in an up-regulation of survivin (an inhibitor of activated caspases), which, however, was not causal for the anti-apoptotic effect of CaeA. Comparing the sequence of CaeA from 25 different C. burnetii isolates we identified an EK (glutamic acid/ lysine) repetition motif as a site of high genetic variability. The EK motif of CaeA was essential for the anti-apoptotic activity of CaeA. From these data, we conclude that the C. burnetii effector protein CaeA interferes with the intrinsic and extrinsic apoptosis pathway. The process requires the EK repetition motif of CaeA, but is independent of the upregulated expression of survivin.
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Affiliation(s)
- Stephanie Bisle
- a Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander Universität (FAU) Erlangen-Nürnberg , Erlangen , Germany
| | - Leonie Klingenbeck
- a Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander Universität (FAU) Erlangen-Nürnberg , Erlangen , Germany
| | - Vítor Borges
- b Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health , Lisbon , Portugal
| | - Katharina Sobotta
- c Friedrich-Loeffler-Institut, Institute of Molecular Pathogenesis , Jena , Germany
| | - Jan Schulze-Luehrmann
- a Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander Universität (FAU) Erlangen-Nürnberg , Erlangen , Germany
| | - Christian Menge
- c Friedrich-Loeffler-Institut, Institute of Molecular Pathogenesis , Jena , Germany
| | - Carsten Heydel
- d Institut für Hygiene und Infektionskrankheiten der Tiere, Justus Liebig Universität Gießen , Gießen , Germany
| | - João Paulo Gomes
- b Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health , Lisbon , Portugal
| | - Anja Lührmann
- a Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander Universität (FAU) Erlangen-Nürnberg , Erlangen , Germany
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