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Li P, Wang H, Sun W, Ding J. Impact of MgtC on the Fitness of Yersinia pseudotuberculosis. Pathogens 2023; 12:1428. [PMID: 38133312 PMCID: PMC10747817 DOI: 10.3390/pathogens12121428] [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: 11/09/2023] [Revised: 12/03/2023] [Accepted: 12/06/2023] [Indexed: 12/23/2023] Open
Abstract
Yersinia pseudotuberculosis is an extracellular foodborne pathogen and usually causes self-limiting diarrhea in healthy humans. MgtC is known as a key subversion factor that contributes to intramacrophage adaptation and intracellular survival in certain important pathogens. Whether MgtC influences the fitness of Y. pseudotuberculosis is unclear. According to in silico analysis, MgtC in Y. pseudotuberculosis might share similar functions with other bacterial pathogens, such as Salmonella. Studies indicated that MgtC was clearly required for Y. pseudotuberculosis growth in vitro and bacterial survival in macrophages under Mg2+ starvation. Transcriptome analysis by RNA-seq indicated that 127 differentially expressed genes (DEGs) (fold change > 2 and p < 0.001) were discovered between wild-type PB1+ and mgtC mutant inside macrophages. However, a lack of MgtC only moderately, albeit significantly, reduced the virulence of Y. pseudotuberculosis in mice. Overall, this study provides additional insights for the role of MgtC in Y. pseudotuberculosis.
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Affiliation(s)
- Peng Li
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China;
| | - Hengtai Wang
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China;
| | - Wei Sun
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY 12208, USA;
| | - Jiabo Ding
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China;
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2
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Yang R, Atkinson S, Chen Z, Cui Y, Du Z, Han Y, Sebbane F, Slavin P, Song Y, Yan Y, Wu Y, Xu L, Zhang C, Zhang Y, Hinnebusch BJ, Stenseth NC, Motin VL. Yersinia pestis and Plague: some knowns and unknowns. ZOONOSES (BURLINGTON, MASS.) 2023; 3:5. [PMID: 37602146 PMCID: PMC10438918 DOI: 10.15212/zoonoses-2022-0040] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/22/2023]
Abstract
Since its first identification in 1894 during the third pandemic in Hong Kong, there has been significant progress of understanding the lifestyle of Yersinia pestis, the pathogen that is responsible for plague. Although we now have some understanding of the pathogen's physiology, genetics, genomics, evolution, gene regulation, pathogenesis and immunity, there are many unknown aspects of the pathogen and its disease development. Here, we focus on some of the knowns and unknowns relating to Y. pestis and plague. We notably focus on some key Y. pestis physiological and virulence traits that are important for its mammal-flea-mammal life cycle but also its emergence from the enteropathogen Yersinia pseudotuberculosis. Some aspects of the genetic diversity of Y. pestis, the distribution and ecology of plague as well as the medical countermeasures to protect our population are also provided. Lastly, we present some biosafety and biosecurity information related to Y. pestis and plague.
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Affiliation(s)
- Ruifu Yang
- Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing 100071, China
| | - Steve Atkinson
- School of Life Sciences, Centre for Biomolecular Science, University of Nottingham, Nottingham, United Kingdom
| | - Ziqi Chen
- Vanke School of Public Health, Tsinghua University, Beijing 100084, China
| | - Yujun Cui
- Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing 100071, China
| | - Zongmin Du
- Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing 100071, China
| | - Yanping Han
- Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing 100071, China
| | - Florent Sebbane
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, U1019-UMR 9017-CIIL-Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Philip Slavin
- Division of History and Politics, University of Stirling, Stirling FK9 4LJ, UK
| | - Yajun Song
- Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing 100071, China
| | - Yanfeng Yan
- Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing 100071, China
| | - Yarong Wu
- Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing 100071, China
| | - Lei Xu
- Vanke School of Public Health, Tsinghua University, Beijing 100084, China
| | - Chutian Zhang
- College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China
| | - Yun Zhang
- Vanke School of Public Health, Tsinghua University, Beijing 100084, China
| | - B. Joseph Hinnebusch
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, NIH, Hamilton, Montana, USA
| | - Nils Chr. Stenseth
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, N-0316 Oslo, Norway
| | - Vladimir L. Motin
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA
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3
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What do we know about osmoadaptation of Yersinia pestis? Arch Microbiol 2021; 204:11. [PMID: 34878588 DOI: 10.1007/s00203-021-02610-1] [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: 05/28/2021] [Revised: 11/23/2021] [Accepted: 11/24/2021] [Indexed: 10/19/2022]
Abstract
The plague agent Yersinia pestis mainly spreads among mammalian hosts and their associated fleas. Production of a successful mammal-flea-mammal life cycle implies that Y. pestis senses and responds to distinct cues in both host and vector. Among these cues, osmolarity is a fundamental parameter. The plague bacillus lives in a tightly regulated environment in the mammalian host, while osmolarity fluctuates in the flea gut (300-550 mOsM). Here, we review the mechanisms that enable Y. pestis to perceive fluctuations in osmolarity, as well as genomic plasticity and physiological adaptation of the bacterium to this stress.
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Groisman EA, Duprey A, Choi J. How the PhoP/PhoQ System Controls Virulence and Mg 2+ Homeostasis: Lessons in Signal Transduction, Pathogenesis, Physiology, and Evolution. Microbiol Mol Biol Rev 2021; 85:e0017620. [PMID: 34191587 PMCID: PMC8483708 DOI: 10.1128/mmbr.00176-20] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The PhoP/PhoQ two-component system governs virulence, Mg2+ homeostasis, and resistance to a variety of antimicrobial agents, including acidic pH and cationic antimicrobial peptides, in several Gram-negative bacterial species. Best understood in Salmonella enterica serovar Typhimurium, the PhoP/PhoQ system consists o-regulated gene products alter PhoP-P amounts, even under constant inducing conditions. PhoP-P controls the abundance of hundreds of proteins both directly, by having transcriptional effects on the corresponding genes, and indirectly, by modifying the abundance, activity, or stability of other transcription factors, regulatory RNAs, protease regulators, and metabolites. The investigation of PhoP/PhoQ has uncovered novel forms of signal transduction and the physiological consequences of regulon evolution.
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Affiliation(s)
- Eduardo A. Groisman
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
- Yale Microbial Sciences Institute, West Haven, Connecticut, USA
| | - Alexandre Duprey
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
| | - Jeongjoon Choi
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
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5
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The Diverse Roles of the Global Transcriptional Regulator PhoP in the Lifecycle of Yersinia pestis. Pathogens 2020; 9:pathogens9121039. [PMID: 33322274 PMCID: PMC7764729 DOI: 10.3390/pathogens9121039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 11/30/2020] [Accepted: 12/04/2020] [Indexed: 11/18/2022] Open
Abstract
Yersinia pestis, the causative agent of plague, has a complex infectious cycle that alternates between mammalian hosts (rodents and humans) and insect vectors (fleas). Consequently, it must adapt to a wide range of host environments to achieve successful propagation. Y. pestis PhoP is a response regulator of the PhoP/PhoQ two-component signal transduction system that plays a critical role in the pathogen’s adaptation to hostile conditions. PhoP is activated in response to various host-associated stress signals detected by the sensor kinase PhoQ and mediates changes in global gene expression profiles that lead to cellular responses. Y. pestis PhoP is required for resistance to antimicrobial peptides, as well as growth under low Mg2+ and other stress conditions, and controls a number of metabolic pathways, including an alternate carbon catabolism. Loss of phoP function in Y. pestis causes severe defects in survival inside mammalian macrophages and neutrophils in vitro, and a mild attenuation in murine plague models in vivo, suggesting its role in pathogenesis. A Y. pestisphoP mutant also exhibits reduced ability to form biofilm and to block fleas in vivo, indicating that the gene is also important for establishing a transmissible infection in this vector. Additionally, phoP promotes the survival of Y. pestis inside the soil-dwelling amoeba Acanthamoeba castellanii, a potential reservoir while the pathogen is quiescent. In this review, we summarize our current knowledge on the mechanisms of PhoP-mediated gene regulation in Y. pestis and examine the significance of the roles played by the PhoP regulon at each stage of the Y. pestis life cycle.
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Role of OB-Fold Protein YdeI in Stress Response and Virulence of Salmonella enterica Serovar Enteritidis. J Bacteriol 2020; 203:JB.00237-20. [PMID: 33106344 DOI: 10.1128/jb.00237-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 10/01/2020] [Indexed: 01/11/2023] Open
Abstract
An essential feature of the pathogenesis of the Salmonella enterica serovar Enteritidis wild type (WT) is its ability to survive under diverse microenvironmental stress conditions, such as encountering antimicrobial peptides (AMPs) or glucose and micronutrient starvation. These stress factors trigger virulence genes carried on Salmonella pathogenicity islands (SPIs) and determine the efficiency of enteric infection. Although the oligosaccharide/oligonucleotide binding-fold (OB-fold) family of proteins has been identified as an important stress response and virulence determinant, functional information on members of this family is currently limited. In this study, we decipher the role of YdeI, which belongs to OB-fold family of proteins, in stress response and virulence of S Enteritidis. When ydeI was deleted, the ΔydeI mutant showed reduced survival during exposure to AMPs or glucose and Mg2+ starvation stress compared to the WT. Green fluorescent protein (GFP) reporter and quantitative real-time PCR (qRT-PCR) assays showed ydeI was transcriptionally regulated by PhoP, which is a major regulator of stress and virulence. Furthermore, the ΔydeI mutant displayed ∼89% reduced invasion into HCT116 cells, ∼15-fold-reduced intramacrophage survival, and downregulation of several SPI-1 and SPI-2 genes encoding the type 3 secretion system apparatus and effector proteins. The mutant showed attenuated virulence compared to the WT, confirmed by its reduced bacterial counts in feces, mesenteric lymph node (mLN), spleen, and liver of C57BL/6 mice. qRT-PCR analyses of the ΔydeI mutant displayed differential expression of 45 PhoP-regulated genes, which were majorly involved in metabolism, transport, membrane remodeling, and drug resistance under different stress conditions. YdeI is, therefore, an important protein that modulates S Enteritidis virulence and adaptation to stress during infection.IMPORTANCE S Enteritidis during its life cycle encounters diverse stress factors inside the host. These intracellular conditions allow activation of specialized secretion systems to cause infection. We report a conserved membrane protein, YdeI, and elucidate its role in protection against various intracellular stress conditions. A key aspect of the study of a pathogen's stress response mechanism is its clinical relevance during host-pathogen interaction. Bacterial adaptation to stress plays a vital role in evolution of a pathogen's resistance to therapeutic agents. Therefore, investigation of the role of YdeI is vital for understanding the molecular basis of regulation of Salmonella pathogenesis. In conclusion, our findings may contribute to finding potential targets to develop new intervention strategies for treatment and prevention of enteric diseases.
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Zhang Y, Liu H, Gu D, Lu X, Zhou X, Xia X. Transcriptomic analysis of PhoR reveals its role in regulation of swarming motility and T3SS expression in Vibrio parahaemolyticus. Microbiol Res 2020; 235:126448. [PMID: 32114363 DOI: 10.1016/j.micres.2020.126448] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 02/21/2020] [Accepted: 02/22/2020] [Indexed: 01/14/2023]
Abstract
Vibrio parahaemolyticus is a common foodborne pathogen in seafood and represents a major threat to human health worldwide. In this study, we identified that PhoR, a histidine kinase, is involved in the regulation of swarming and flagella assembly. RNA sequencing analysis showed that 1122 genes were differentially expressed in PhoR mutant, including 394 upregulated and 728 downregulated genes. KEGG enrichment and heatmap analysis demonstrated that the bacterial secretion system, flagella assembly and chemotaxis pathways were significantly downregulated in PhoR mutant, while the microbial metabolism in diverse environments and carbon metabolism pathways were upregulated in PhoR mutant. qRT-PCR further confirmed that genes responsible for the type III secretion system (T3SS), swarming and the thermostable direct hemolysin were positively regulated by PhoR. Phosphorylation assays suggested that PhoR was highly activated in BHI medium compared to LB medium. Taken together, these data suggested that activated PhoR contributes to the expression of swarming motility and secretion system genes in Vibrio parahaemolyticus.
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Affiliation(s)
- Yibei Zhang
- College of Food Science and Engineering, Sino-US Joint Research Center, Northwest A&F University, Yangling, Shaanxi, 712100, China; Department of Pathobiology and Veterinary Science, University of Connecticut, Storrs, CT 06269-3089, USA
| | - Huanhuan Liu
- College of Food Science and Engineering, Sino-US Joint Research Center, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Dan Gu
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Xingxu Lu
- Department of Materials Science and Engineering and Institute of Materials Science, University of Connecticut, Storrs, CT 06269-3136, USA
| | - Xiaohui Zhou
- Department of Pathobiology and Veterinary Science, University of Connecticut, Storrs, CT 06269-3089, USA.
| | - Xiaodong Xia
- College of Food Science and Engineering, Sino-US Joint Research Center, Northwest A&F University, Yangling, Shaanxi, 712100, China; School of Food Science and Technology, National Engineering Research Center of Seafood, Dalian Polytechnic University, 1 Qinggongyuan, Ganjingzi District, Dalian, Liaoning, 116034 China.
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8
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Synthetic hydrophobic peptides derived from MgtR weaken Salmonella pathogenicity and work with a different mode of action than endogenously produced peptides. Sci Rep 2019; 9:15253. [PMID: 31649255 PMCID: PMC6813294 DOI: 10.1038/s41598-019-51760-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Accepted: 09/24/2019] [Indexed: 12/03/2022] Open
Abstract
Due to the antibiotic resistance crisis, novel therapeutic strategies need to be developed against bacterial pathogens. Hydrophobic bacterial peptides (small proteins under 50 amino acids) have emerged as regulatory molecules that can interact with bacterial membrane proteins to modulate their activity and/or stability. Among them, the Salmonella MgtR peptide promotes the degradation of MgtC, a virulence factor involved in Salmonella intramacrophage replication, thus providing the basis for an antivirulence strategy. We demonstrate here that endogenous overproduction of MgtR reduced Salmonella replication inside macrophages and lowered MgtC protein level, whereas a peptide variant of MgtR (MgtR-S17I), which does not interact with MgtC, had no effect. We then used synthetic peptides to evaluate their action upon exogenous addition. Unexpectedly, upon addition of synthetic peptides, both MgtR and its variant MgtR-S17I reduced Salmonella intramacrophage replication and lowered MgtC and MgtB protein levels, suggesting a different mechanism of action of exogenously added peptides versus endogenously produced peptides. The synthetic peptides did not act by reducing bacterial viability. We next tested their effect on various recombinant proteins produced in Escherichia coli and showed that the level of several inner membrane proteins was strongly reduced upon addition of both peptides, whereas cytoplasmic or outer membrane proteins remained unaffected. Moreover, the α-helical structure of synthetic MgtR is important for its biological activity, whereas helix-helix interacting motif is dispensable. Cumulatively, these results provide perspectives for new antivirulence strategies with the use of peptides that act by reducing the level of inner membrane proteins, including virulence factors.
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Spyrou MA, Keller M, Tukhbatova RI, Scheib CL, Nelson EA, Andrades Valtueña A, Neumann GU, Walker D, Alterauge A, Carty N, Cessford C, Fetz H, Gourvennec M, Hartle R, Henderson M, von Heyking K, Inskip SA, Kacki S, Key FM, Knox EL, Later C, Maheshwari-Aplin P, Peters J, Robb JE, Schreiber J, Kivisild T, Castex D, Lösch S, Harbeck M, Herbig A, Bos KI, Krause J. Phylogeography of the second plague pandemic revealed through analysis of historical Yersinia pestis genomes. Nat Commun 2019; 10:4470. [PMID: 31578321 PMCID: PMC6775055 DOI: 10.1038/s41467-019-12154-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 08/15/2019] [Indexed: 12/30/2022] Open
Abstract
The second plague pandemic, caused by Yersinia pestis, devastated Europe and the nearby regions between the 14th and 18th centuries AD. Here we analyse human remains from ten European archaeological sites spanning this period and reconstruct 34 ancient Y. pestis genomes. Our data support an initial entry of the bacterium through eastern Europe, the absence of genetic diversity during the Black Death, and low within-outbreak diversity thereafter. Analysis of post-Black Death genomes shows the diversification of a Y. pestis lineage into multiple genetically distinct clades that may have given rise to more than one disease reservoir in, or close to, Europe. In addition, we show the loss of a genomic region that includes virulence-related genes in strains associated with late stages of the pandemic. The deletion was also identified in genomes connected with the first plague pandemic (541-750 AD), suggesting a comparable evolutionary trajectory of Y. pestis during both events.
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Affiliation(s)
- Maria A Spyrou
- Max Planck Institute for the Science of Human History, 07745, Jena, Germany.
- Institute for Archaeological Sciences, University of Tübingen, 72070, Tübingen, Germany.
| | - Marcel Keller
- Max Planck Institute for the Science of Human History, 07745, Jena, Germany
- SNSB, State Collection for Anthropology and Palaeoanatomy Munich, 80333, Munich, Germany
| | - Rezeda I Tukhbatova
- Max Planck Institute for the Science of Human History, 07745, Jena, Germany
- Laboratory of Structural Biology, Kazan Federal University, Kazan, Russian Federation, 420008
| | | | - Elizabeth A Nelson
- Max Planck Institute for the Science of Human History, 07745, Jena, Germany
- Institute for Archaeological Sciences, University of Tübingen, 72070, Tübingen, Germany
| | | | - Gunnar U Neumann
- Max Planck Institute for the Science of Human History, 07745, Jena, Germany
| | - Don Walker
- MOLA (Museum of London Archaeology), London, N1 7ED, UK
| | - Amelie Alterauge
- Department of Physical Anthropology, Institute for Forensic Medicine, University of Bern, 3007, Bern, Switzerland
| | - Niamh Carty
- MOLA (Museum of London Archaeology), London, N1 7ED, UK
| | - Craig Cessford
- Department of Archaeology, University of Cambridge, Downing St, Cambridge, CB2 3ER, UK
| | - Hermann Fetz
- Archaeological Service, State Archive Nidwalden, 6371, Nidwalden, Switzerland
| | - Michaël Gourvennec
- Archeodunum SAS, Agency Toulouse, 8 allée Michel de Montaigne, 31770, Colomiers, France
| | - Robert Hartle
- MOLA (Museum of London Archaeology), London, N1 7ED, UK
| | | | - Kristin von Heyking
- SNSB, State Collection for Anthropology and Palaeoanatomy Munich, 80333, Munich, Germany
| | - Sarah A Inskip
- McDonald Institute for Archaeological Research, University of Cambridge, Downing St, Cambridge, CB2 3ER, UK
| | - Sacha Kacki
- PACEA, CNRS Institute, Université de Bordeaux, 33615, Pessac, France
- Department of Archaeology, Durham University, South Rd, Durham, DH1 3LE, UK
| | - Felix M Key
- Institute for Medical Engineering and Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | | | - Christian Later
- Bavarian State Department of Monuments and Sites, 80539, Munich, Germany
| | | | - Joris Peters
- SNSB, State Collection for Anthropology and Palaeoanatomy Munich, 80333, Munich, Germany
- ArchaeoBioCenter and Department of Veterinary Sciences, Institute of Palaeoanatomy, Domestication Research and the History of Veterinary Medicine, Ludwig Maximilian University Munich, Kaulbachstr. 37/III, 80539, Munich, Germany
| | - John E Robb
- Department of Archaeology, University of Cambridge, Downing St, Cambridge, CB2 3ER, UK
| | | | - Toomas Kivisild
- Institute of Genomics, University of Tartu, Riia 23b, 51010, Tartu, Estonia
- Department of Human Genetics, Katholieke Universiteit Leuven, 3000, Leuven, Belgium
| | - Dominique Castex
- PACEA, CNRS Institute, Université de Bordeaux, 33615, Pessac, France
| | - Sandra Lösch
- Department of Physical Anthropology, Institute for Forensic Medicine, University of Bern, 3007, Bern, Switzerland
| | - Michaela Harbeck
- SNSB, State Collection for Anthropology and Palaeoanatomy Munich, 80333, Munich, Germany
| | - Alexander Herbig
- Max Planck Institute for the Science of Human History, 07745, Jena, Germany
| | - Kirsten I Bos
- Max Planck Institute for the Science of Human History, 07745, Jena, Germany.
| | - Johannes Krause
- Max Planck Institute for the Science of Human History, 07745, Jena, Germany.
- Institute for Archaeological Sciences, University of Tübingen, 72070, Tübingen, Germany.
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The Salmonella virulence protein MgtC promotes phosphate uptake inside macrophages. Nat Commun 2019; 10:3326. [PMID: 31346161 PMCID: PMC6658541 DOI: 10.1038/s41467-019-11318-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Accepted: 07/05/2019] [Indexed: 02/06/2023] Open
Abstract
The MgtC virulence protein from the intracellular pathogen Salmonella enterica is required for its intramacrophage survival and virulence in mice and this requirement of MgtC is conserved in several intracellular pathogens including Mycobacterium tuberculosis. Despite its critical role in survival within macrophages, only a few molecular targets of the MgtC protein have been identified. Here, we report that MgtC targets PhoR histidine kinase and activates phosphate transport independently of the available phosphate concentration. A single amino acid substitution in PhoR prevents its binding to MgtC, thus abrogating MgtC-mediated phosphate transport. Surprisingly, the removal of MgtC’s effect on the ability to transport phosphate renders Salmonella hypervirulent and decreases a non-replicating population inside macrophages, indicating that MgtC-mediated phosphate transport is required for normal Salmonella pathogenesis. This provides an example of a virulence protein directly activating a pathogen’s phosphate transport inside host. The virulence factor MgtC is essential for intracellular macrophage survival of Salmonella enterica. Here, the authors show that MgtC targets the PhoB/PhoR regulatory system leading to phosphate uptake inside macrophages and that both phoR mutation and phoB deletion renders Salmonella hypervirulent in mice.
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11
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Song X, Hou M, Tu J, Xue M, Shao Y, Jiang H, Liu H, Xue T, Wang G, Qi K. Outer membrane proteins YbjX and PagP co-regulate motility in Escherichia coli via the bacterial chemotaxis pathway. Res Vet Sci 2019; 125:279-284. [PMID: 31326704 DOI: 10.1016/j.rvsc.2019.07.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 05/25/2019] [Accepted: 07/10/2019] [Indexed: 02/08/2023]
Abstract
Mutation of the PhoP/Q two-component system decreases the expression of ybjX and pagP encoding outer membrane proteins, and mutation of ybjX or pagP attenuates avian pathogenic Escherichia coli (APEC) pathogenicity. However, whether ybjX/pagP mutation (double-deletion mutant) has a synergistic effect on pathogenicity remains unknown. Herein, electrophoresis mobility shift assay (EMSA) experiments showed that the PhoP/Q system regulated ybjX and pagP transcription indirectly. The APECΔybjX/pagP mutant strain, constructed using the Red recombination method, exhibited reduced invasion of chicken embryo fibroblast (DF-1) cells, but had no effect on virulence in a chicken model. Using RNA sequencing to identify differential mRNAs in APECΔybjXΔpagP and native strains, we revealed up-regulation of genes involved in the bacterial chemotaxis pathway. The ybjX/pagP mutant strain displayed significantly increased motility, suggesting that double deletion of ybjX and pagP enhances motility via the bacterial chemotaxis pathway.
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Affiliation(s)
- Xiangjun Song
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Manman Hou
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Jian Tu
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Mei Xue
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Ying Shao
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Huyan Jiang
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Hongmei Liu
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Ting Xue
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Guijun Wang
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Kezong Qi
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China.
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12
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Zhang Q, Xin Y, Zhao H, Liu R, Xu X, Yan Y, Kong Z, Wang T, Qi Z, Zhang Q, You Y, Song Y, Cui Y, Yang R, Zhang X, Du Z. Human Macrophages Clear the Biovar Microtus Strain of Yersinia pestis More Efficiently Than Murine Macrophages. Front Cell Infect Microbiol 2019; 9:111. [PMID: 31069175 PMCID: PMC6491462 DOI: 10.3389/fcimb.2019.00111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 03/29/2019] [Indexed: 12/20/2022] Open
Abstract
Yersinia pestis is the etiological agent of the notorious plague that has claimed millions of deaths in history. Of the four known Y. pestis biovars (Antiqua, Medievalis, Orientalis, and Microtus), Microtus strains are unique for being highly virulent in mice but avirulent in humans. Here, human peripheral lymphocytes were infected with the fully virulent 141 strain or the Microtus strain 201, and their transcriptomes were determined and compared. The most notable finding was that robust responses in the pathways for cytokine-cytokine receptor interaction, chemokine signaling pathway, Toll-like receptor signaling and Jak-STAT signaling were induced at 2 h post infection (hpi) in the 201- but not the 141-infected lymphocytes, suggesting that human lymphocytes might be able to constrain infections caused by strain 201 but not 141. Consistent with the transcriptome results, much higher IFN-γ and IL-1β were present in the supernatants from the 201-infected lymphocytes, while inflammatory inhibitory IL-10 levels were higher in the 141-infected lymphocytes. The expressions of CSTD and SLC11A1, both of which are functional components of the lysosome, increased in the 201-infected human macrophage-like U937 cells. Further assessment of the survival rate of the 201 bacilli in the U937 cells and murine macrophage RAW 264.7 cells revealed no viable bacteria in the U937 cells at 32 hpi.; however, about 5–10% of the bacteria were still alive in the RAW264.7 cells. Our results indicate that human macrophages can clear the intracellular Y. pestis 201 bacilli more efficiently than murine macrophages, probably by interfering with critical host immune responses, and this could partially account for the host-specific pathogenicity of Y. pestis Microtus strains.
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Affiliation(s)
- Qingwen Zhang
- Qinghai Institute for Endemic Disease Prevention and Control, Xining, China
| | - Youquan Xin
- Qinghai Institute for Endemic Disease Prevention and Control, Xining, China
| | - Haihong Zhao
- Qinghai Institute for Endemic Disease Prevention and Control, Xining, China
| | - Rongjiao Liu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Xiaoqing Xu
- Qinghai Institute for Endemic Disease Prevention and Control, Xining, China
| | - Yanfeng Yan
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Zhipeng Kong
- Qinghai Institute for Endemic Disease Prevention and Control, Xining, China
| | - Tong Wang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Zhizhen Qi
- Qinghai Institute for Endemic Disease Prevention and Control, Xining, China
| | - Qi Zhang
- Qinghai Institute for Endemic Disease Prevention and Control, Xining, China
| | - Yang You
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Yajun Song
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Yujun Cui
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Ruifu Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Xuefei Zhang
- Qinghai Institute for Endemic Disease Prevention and Control, Xining, China
| | - Zongmin Du
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
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13
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Moussouni M, Nogaret P, Garai P, Ize B, Vivès E, Blanc-Potard AB. Activity of a Synthetic Peptide Targeting MgtC on Pseudomonas aeruginosa Intramacrophage Survival and Biofilm Formation. Front Cell Infect Microbiol 2019; 9:84. [PMID: 31001488 PMCID: PMC6454036 DOI: 10.3389/fcimb.2019.00084] [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: 12/20/2018] [Accepted: 03/11/2019] [Indexed: 01/29/2023] Open
Abstract
Antivirulence strategies aim to target pathogenicity factors while bypassing the pressure on the bacterium to develop resistance. The MgtC membrane protein has been proposed as an attractive target that is involved in the ability of several major bacterial pathogens, including Pseudomonas aeruginosa, to survive inside macrophages. In liquid culture, P. aeruginosa MgtC acts negatively on biofilm formation. However, a putative link between these two functions of MgtC in P. aeruginosa has not been experimentally addressed. In the present study, we first investigated the contribution of exopolysaccharides (EPS) in the intramacrophage survival defect and biofilm increase of mgtC mutant. Within infected macrophages, expression of EPS genes psl and alg was increased in a P. aeruginosa mgtC mutant strain comparatively to wild-type strain. However, the intramacrophage survival defect of mgtC mutant was not rescued upon introduction of psl or alg mutation, suggesting that MgtC intramacrophage role is unrelated to EPS production, whereas the increased biofilm formation of mgtC mutant was partially suppressed by introduction of psl mutation. We aimed to develop an antivirulence strategy targeting MgtC, by taking advantage of a natural antagonistic peptide, MgtR. Heterologous expression of mgtR in P. aeruginosa PAO1 was shown to reduce its ability to survive within macrophages. We investigated for the first time the biological effect of a synthetic MgtR peptide on P. aeruginosa. Exogenously added synthetic MgtR peptide lowered the intramacrophage survival of wild-type P. aeruginosa PAO1, thus mimicking the phenotype of an mgtC mutant as well as the effect of endogenously produced MgtR peptide. In correlation with this finding, addition of MgtR peptide to bacterial culture strongly reduced MgtC protein level, without reducing bacterial growth or viability, thus differing from classical antimicrobial peptides. On the other hand, the addition of exogenous MgtR peptide did not affect significantly biofilm formation, indicating an action toward EPS-independent phenotype rather than EPS-related phenotype. Cumulatively, our results show an antivirulence action of synthetic MgtR peptide, which may be more potent against acute infection, and provide a proof of concept for further exploitation of anti-Pseudomonas strategies.
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Affiliation(s)
- Malika Moussouni
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université Montpellier, Montpellier, France.,CNRS, UMR5235, Montpellier, France
| | - Pauline Nogaret
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université Montpellier, Montpellier, France.,CNRS, UMR5235, Montpellier, France
| | - Preeti Garai
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université Montpellier, Montpellier, France.,CNRS, UMR5235, Montpellier, France
| | - Bérengère Ize
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie de la Méditerranée, CNRS & Aix-Marseille University of Marseille, Marseille, France
| | - Eric Vivès
- Centre de Recherche en Biologie cellulaire de Montpellier, CNRS UMR 5237, Montpellier, France
| | - Anne-Béatrice Blanc-Potard
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université Montpellier, Montpellier, France.,CNRS, UMR5235, Montpellier, France
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14
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Yang K, He Y, Park CG, Kang YS, Zhang P, Han Y, Cui Y, Bulgheresi S, Anisimov AP, Dentovskaya SV, Ying X, Jiang L, Ding H, Njiri OA, Zhang S, Zheng G, Xia L, Kan B, Wang X, Jing H, Yan M, Li W, Wang Y, Xiamu X, Chen G, Ma D, Bartra SS, Plano GV, Klena JD, Yang R, Skurnik M, Chen T. Yersinia pestis Interacts With SIGNR1 (CD209b) for Promoting Host Dissemination and Infection. Front Immunol 2019; 10:96. [PMID: 30915064 PMCID: PMC6422942 DOI: 10.3389/fimmu.2019.00096] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Accepted: 01/14/2019] [Indexed: 01/01/2023] Open
Abstract
Yersinia pestis, a Gram-negative bacterium and the etiologic agent of plague, has evolved from Yersinia pseudotuberculosis, a cause of a mild enteric disease. However, the molecular and biological mechanisms of how Y. pseudotuberculosis evolved to such a remarkably virulent pathogen, Y. pestis, are not clear. The ability to initiate a rapid bacterial dissemination is a characteristic hallmark of Y. pestis infection. A distinguishing characteristic between the two Yersinia species is that Y. pseudotuberculosis strains possess an O-antigen of lipopolysaccharide (LPS) while Y. pestis has lost the O-antigen during evolution and therefore exposes its core LPS. In this study, we showed that Y. pestis utilizes its core LPS to interact with SIGNR1 (CD209b), a C-type lectin receptor on antigen presenting cells (APCs), leading to bacterial dissemination to lymph nodes, spleen and liver, and the initiation of a systemic infection. We therefore propose that the loss of O-antigen represents a critical step in the evolution of Y. pseudotuberculosis into Y. pestis in terms of hijacking APCs, promoting bacterial dissemination and causing the plague.
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Affiliation(s)
- Kun Yang
- Department of Clinical Immunology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department of Pathogen Biology and Immunology, Shihezi University School of Medicine, Shihezi, China
| | - Yingxia He
- Department of Clinical Immunology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chae Gyu Park
- Laboratory of Immunology, Brain Korea 21 PLUS Project for Medical Science, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, South Korea
| | - Young Sun Kang
- Laboratory of Immunology, Brain Korea 21 PLUS Project for Medical Science, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, South Korea
| | - Pei Zhang
- Department of Biomedical Sciences, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States
| | - Yanping Han
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Yujun Cui
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Silvia Bulgheresi
- Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria
| | - Andrey P Anisimov
- State Research Center for Applied Microbiology and Biotechnology, Obolensk, Russia
| | | | - Xiaoling Ying
- Department of Clinical Immunology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Lingyu Jiang
- Department of Clinical Immunology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Honghui Ding
- Department of Clinical Immunology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Olivia Adhiambo Njiri
- Department of Clinical Immunology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department of Biological Sciences, Faculty of Science, Technology and Engineering, Chuka University, Chuka, Kenya
| | - Shusheng Zhang
- Department of Biomedical Sciences, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States
| | - Guoxing Zheng
- Department of Biomedical Sciences, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States
| | - Lianxu Xia
- National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Biao Kan
- National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Xin Wang
- National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Huaiqi Jing
- National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Meiying Yan
- National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Wei Li
- National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Yuanzhi Wang
- Department of Pathogen Biology and Immunology, Shihezi University School of Medicine, Shihezi, China
| | - Xiding Xiamu
- Department of Pathogen Biology and Immunology, Shihezi University School of Medicine, Shihezi, China
| | - Gang Chen
- Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ding Ma
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Sara Schesser Bartra
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Gregory V Plano
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL, United States
| | - John D Klena
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Ruifu Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Mikael Skurnik
- Department of Bacteriology and Immunology, Haartman Institute, Helsinki University Central Hospital Laboratory Diagnostics, University of Helsinki, Helsinki, Finland
| | - Tie Chen
- Department of Clinical Immunology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department of Pathogen Biology and Immunology, Shihezi University School of Medicine, Shihezi, China
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15
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Transcriptional Regulation Between the Two Global Regulators RovA and CRP in Yersinia pestis biovar Microtus. Curr Microbiol 2018; 75:1634-1641. [PMID: 30291406 DOI: 10.1007/s00284-018-1571-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 09/18/2018] [Indexed: 12/19/2022]
Abstract
Yersinia pestis is a dangerous bacterial pathogen that can cause plague. Both RovA and cyclic AMP receptor protein (cAMP-CRP) are required for regulating biofilm- and virulence-related genes in Y. pestis. In this study, the transcriptional regulation between RovA and cAMP-CRP were analyzed by using primer extension, quantitative RT-PCR, LacZ fusion, and electrophoretic mobility shift assay. The results indicated that RovA repressed crp transcription in an indirect manner, while that RovA had no regulatory action on cyaA at the transcriptional level. In addition, cAMP-CRP did not regulate the transcription of rovA. Taken together with our previous results, complex regulatory interactions of RovA, cAMP-CRP, and PhoP/PhoQ in Y. pestis were revealed, which would promote us gain deeper understanding about coordinative modulation of biofilm- and virulence-related regulator genes.
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16
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A rule governing the FtsH-mediated proteolysis of the MgtC virulence protein from Salmonella enterica serovar Typhimurium. J Microbiol 2018; 56:565-570. [PMID: 30047085 DOI: 10.1007/s12275-018-8245-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 06/11/2018] [Accepted: 06/15/2018] [Indexed: 12/24/2022]
Abstract
A tightly controlled turnover of membrane proteins is required for lipid bilayer stability, cell metabolism, and cell viability. Among the energy-dependent AAA+ proteases in Salmonella, FtsH is the only membrane-bound protease that contributes to the quality control of membrane proteins. FtsH preferentially degrades the C-terminus or N-terminus of misfolded, misassembled, or damaged proteins to maintain physiological functions. We found that FtsH hydrolyzes the Salmonella MgtC virulence protein when we substitute the MgtC 226th Trp, which is well conserved in other intracellular pathogens and normally protects MgtC from the FtsH-mediated proteolysis. Here we investigate a rule determining the FtsH-mediated proteolysis of the MgtC protein at Trp226 residue. Substitution of MgtC tryptophan 226th residue to alanine, glycine, or tyrosine leads to MgtC proteolysis in a manner dependent on the FtsH protease whereas substitution to phenylalanine, methionine, isoleucine, leucine, or valine resists MgtC degradation by FtsH. These data indicate that a large and hydrophobic side chain at 226th residue is required for protection from the FtsH-mediated MgtC proteolysis.
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17
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Yeom J, Pontes MH, Choi J, Groisman EA. A protein that controls the onset of a Salmonella virulence program. EMBO J 2018; 37:embj.201796977. [PMID: 29858228 DOI: 10.15252/embj.201796977] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 04/11/2018] [Accepted: 04/18/2018] [Indexed: 12/16/2022] Open
Abstract
The mechanism of action and contribution to pathogenesis of many virulence genes are understood. By contrast, little is known about anti-virulence genes, which contribute to the start, progression, and outcome of an infection. We now report how an anti-virulence factor in Salmonella enterica serovar Typhimurium dictates the onset of a genetic program that governs metabolic adaptations and pathogen survival in host tissues. Specifically, we establish that the anti-virulence protein CigR directly restrains the virulence protein MgtC, thereby hindering intramacrophage survival, inhibition of ATP synthesis, stabilization of cytoplasmic pH, and gene transcription by the master virulence regulator PhoP. We determine that, like MgtC, CigR localizes to the bacterial inner membrane and that its C-terminal domain is critical for inhibition of MgtC. As in many toxin/anti-toxin genes implicated in antibiotic tolerance, the mgtC and cigR genes are part of the same mRNA. However, cigR is also transcribed from a constitutive promoter, thereby creating a threshold of CigR protein that the inducible MgtC protein must overcome to initiate a virulence program critical for pathogen persistence in host tissues.
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Affiliation(s)
- Jinki Yeom
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT, USA
| | - Mauricio H Pontes
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT, USA.,Yale Microbial Sciences Institute, West Haven, CT, USA
| | - Jeongjoon Choi
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT, USA
| | - Eduardo A Groisman
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT, USA .,Yale Microbial Sciences Institute, West Haven, CT, USA
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18
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Fukuto HS, Vadyvaloo V, McPhee JB, Poinar HN, Holmes EC, Bliska JB. A Single Amino Acid Change in the Response Regulator PhoP, Acquired during Yersinia pestis Evolution, Affects PhoP Target Gene Transcription and Polymyxin B Susceptibility. J Bacteriol 2018; 200:e00050-18. [PMID: 29440252 PMCID: PMC5892123 DOI: 10.1128/jb.00050-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 02/06/2018] [Indexed: 11/20/2022] Open
Abstract
Yersinia pestis, the causative agent of plague, evolved from the closely related pathogen Yersinia pseudotuberculosis During its emergence, Y. pestis is believed to have acquired its unique pathogenic characteristics through numerous gene gains/losses, genomic rearrangements, and single nucleotide polymorphism (SNP) changes. One such SNP creates a single amino acid variation in the DNA binding domain of PhoP, the response regulator in the PhoP/PhoQ two-component system. Y. pseudotuberculosis and the basal human-avirulent strains of Y. pestis harbor glycines at position 215 of PhoP, whereas the modern human-virulent strains (e.g., KIM and CO92) harbor serines at this residue. Since PhoP plays multiple roles in the adaptation of Y. pestis to stressful host conditions, we tested whether this amino acid substitution affects PhoP activity or the ability of Y. pestis to survive in host environments. Compared to the parental KIM6+ strain carrying the modern allele of phoP (phoP-S215), a derivative carrying the basal allele (phoP-G215) exhibited slightly defective growth under a low-Mg2+ condition and decreased transcription of a PhoP target gene, ugd, as well as an ∼8-fold increase in the susceptibility to the antimicrobial peptide polymyxin B. The phoP-G215 strain showed no apparent defect in flea colonization, although a phoP-null mutant showed decreased flea infectivity in competition experiments. Our results suggest that the amino acid variation at position 215 of PhoP causes subtle changes in the PhoP activity and raise the possibility that the change in this residue have contributed to the evolution of increased virulence in Y. pestisIMPORTANCEY. pestis acquired a single nucleotide polymorphism (SNP) in phoP when the highly human-virulent strains diverged from less virulent basal strains, resulting in an amino acid substitution in the DNA binding domain of the PhoP response regulator. We show that Y. pestis carrying the modern phoP allele has an increased ability to induce the PhoP-regulated ugd gene and resist antimicrobial peptides compared to an isogenic strain carrying the basal allele. Given the important roles PhoP plays in host adaptation, the results raise an intriguing possibility that this amino acid substitution contributed to the evolution of increased virulence in Y. pestis Additionally, we present the first evidence that phoP confers a survival fitness advantage to Y. pestis inside the flea midgut.
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Affiliation(s)
- Hana S Fukuto
- Center for Infectious Diseases, Stony Brook University, Stony Brook, New York, USA
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, USA
- Clinical Laboratory Sciences Program, School of Health Technology and Management, Stony Brook University, Stony Brook, New York, USA
| | - Viveka Vadyvaloo
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, USA
| | - Joseph B McPhee
- Department of Chemistry and Biology, Ryerson University, Toronto, Canada
| | - Hendrik N Poinar
- McMaster Ancient DNA Center, Department of Anthropology, McMaster University, Hamilton, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
- Humans and the Microbiome Program, Canadian Institute for Advanced Research, Toronto, Ontario, Canada
| | - Edward C Holmes
- Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Sydney, Australia
- Charles Perkins Centre, School of Life and Environmental Sciences, The University of Sydney, Sydney, Australia
- Sydney Medical School, The University of Sydney, Sydney, Australia
| | - James B Bliska
- Center for Infectious Diseases, Stony Brook University, Stony Brook, New York, USA
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, USA
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19
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Song X, Li C, Qi K, Tu J, Liu H, Xue T. The role of the outer membrane protein gene ybjX in the pathogenicity of avian pathogenic Escherichia coli. Avian Pathol 2018. [DOI: 10.1080/03079457.2018.1448053] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Xiangjun Song
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei, People’s Republic of China
| | - Chunxiao Li
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei, People’s Republic of China
| | - Kezong Qi
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei, People’s Republic of China
| | - Jian Tu
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei, People’s Republic of China
| | - Hongmei Liu
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei, People’s Republic of China
| | - Ting Xue
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei, People’s Republic of China
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20
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Yersinia pestis Targets the Host Endosome Recycling Pathway during the Biogenesis of the Yersinia-Containing Vacuole To Avoid Killing by Macrophages. mBio 2018; 9:mBio.01800-17. [PMID: 29463656 PMCID: PMC5821078 DOI: 10.1128/mbio.01800-17] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Yersinia pestis has evolved many strategies to evade the innate immune system. One of these strategies is the ability to survive within macrophages. Upon phagocytosis, Y. pestis prevents phagolysosome maturation and establishes a modified compartment termed the Yersinia-containing vacuole (YCV). Y. pestis actively inhibits the acidification of this compartment, and eventually, the YCV transitions from a tight-fitting vacuole into a spacious replicative vacuole. The mechanisms to generate the YCV have not been defined. However, we hypothesized that YCV biogenesis requires Y. pestis interactions with specific host factors to subvert normal vesicular trafficking. In order to identify these factors, we performed a genome-wide RNA interference (RNAi) screen to identify host factors required for Y. pestis survival in macrophages. This screen revealed that 71 host proteins are required for intracellular survival of Y. pestis. Of particular interest was the enrichment for genes involved in endosome recycling. Moreover, we demonstrated that Y. pestis actively recruits Rab4a and Rab11b to the YCV in a type three secretion system-independent manner, indicating remodeling of the YCV by Y. pestis to resemble a recycling endosome. While recruitment of Rab4a was necessary to inhibit YCV acidification and lysosomal fusion early during infection, Rab11b appeared to contribute to later stages of YCV biogenesis. We also discovered that Y. pestis disrupts global host endocytic recycling in macrophages, possibly through sequestration of Rab11b, and this process is required for bacterial replication. These data provide the first evidence that Y. pestis targets the host endocytic recycling pathway to avoid phagolysosomal maturation and generate the YCV. Yersinia pestis can infect and survive within macrophages. However, the mechanisms that the bacterium use to subvert killing by these phagocytes have not been defined. To provide a better understanding of these mechanisms, we used an RNAi approach to identify host factors required for intracellular Y. pestis survival. This approach revealed that the host endocytic recycling pathway is essential for Y. pestis to avoid clearance by the macrophage. We further demonstrate that Y. pestis remodels the phagosome to resemble a recycling endosome, allowing the bacterium to avoid the normal phagolysosomal maturation pathway. Moreover, we show that infection with Y. pestis disrupts normal recycling in the macrophage and that disruption is required for bacterial replication. These findings provide the first evidence that Y. pestis targets the host endocytic recycling pathway in order to evade killing by macrophages.
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21
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Markman DW, Antolin MF, Bowen RA, Wheat WH, Woods M, Gonzalez-Juarrero M, Jackson M. Yersinia pestis Survival and Replication in Potential Ameba Reservoir. Emerg Infect Dis 2018; 24:294-302. [PMID: 29350155 PMCID: PMC5782900 DOI: 10.3201/eid2402.171065] [Citation(s) in RCA: 18] [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] [Indexed: 11/19/2022] Open
Abstract
Plague ecology is characterized by sporadic epizootics, then periods of dormancy. Building evidence suggests environmentally ubiquitous amebae act as feral macrophages and hosts to many intracellular pathogens. We conducted environmental genetic surveys and laboratory co-culture infection experiments to assess whether plague bacteria were resistant to digestion by 5 environmental ameba species. First, we demonstrated that Yersinia pestis is resistant or transiently resistant to various ameba species. Second, we showed that Y. pestis survives and replicates intracellularly within Dictyostelium discoideum amebae for ˃48 hours postinfection, whereas control bacteria were destroyed in <1 hour. Finally, we found that Y. pestis resides within ameba structures synonymous with those found in infected human macrophages, for which Y. pestis is a competent pathogen. Evidence supporting amebae as potential plague reservoirs stresses the importance of recognizing pathogen-harboring amebae as threats to public health, agriculture, conservation, and biodefense.
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22
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Lin Z, Cai X, Chen M, Ye L, Wu Y, Wang X, Lv Z, Shang Y, Qu D. Virulence and Stress Responses of Shigella flexneri Regulated by PhoP/PhoQ. Front Microbiol 2018; 8:2689. [PMID: 29379483 PMCID: PMC5775216 DOI: 10.3389/fmicb.2017.02689] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 12/26/2017] [Indexed: 12/31/2022] Open
Abstract
The two-component signal transduction system PhoP/PhoQ is an important regulator for stress responses and virulence in most Gram-negative bacteria, but characterization of PhoP/PhoQ in Shigella has not been thoroughly investigated. In the present study, we found that deletion of phoPQ (ΔphoPQ) from Shigella flexneri 2a 301 (Sf301) resulted in a significant decline (reduced by more than 15-fold) in invasion of HeLa cells and Caco-2 cells, and less inflammation (− or +) compared to Sf301 (+++) in the guinea pig Sereny test. In low Mg2+ (10 μM) medium or pH 5 medium, the ΔphoPQ strain exhibited a growth deficiency compared to Sf301. The ΔphoPQ strain was more sensitive than Sf301 to polymyxin B, an important antimicrobial agent for treating multi-resistant Gram-negative infections. By comparing the transcriptional profiles of ΔphoPQ and Sf301 using DNA microarrays, 117 differentially expressed genes (DEGs) were identified, which were involved in Mg2+ transport, lipopolysaccharide modification, acid resistance, bacterial virulence, respiratory, and energy metabolism. Based on the reported PhoP box motif [(T/G) GTTTA-5nt-(T/G) GTTTA], we screened 38 suspected PhoP target operons in S. flexneri, and 11 of them (phoPQ, mgtA, slyB, yoaE, yrbL, icsA, yhiWX, rstA, hdeAB, pagP, and shf–rfbU-virK-msbB2) were demonstrated to be PhoP-regulated genes based on electrophoretic mobility shift assays and β-galactosidase assays. One of these PhoP-regulated genes, icsA, is a well-known virulence factor in S. flexneri. In conclusion, our data suggest that the PhoP/PhoQ system modulates S. flexneri virulence (in an icsA-dependent manner) and stress responses of Mg2+, pH and antibacterial peptides.
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Affiliation(s)
- Zhiwei Lin
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Science and Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Xia Cai
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Science and Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Mingliang Chen
- Shanghai Municipal Center for Disease Control and Prevention, Shanghai, China
| | - Lina Ye
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Science and Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Yang Wu
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Science and Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Xiaofei Wang
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Science and Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Zhihui Lv
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Science and Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Yongpeng Shang
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Science and Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Di Qu
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Science and Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
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Dong F, Xia L, Lu R, Zhao X, Zhang Y, Zhang Y, Huang X. The malS-5'UTR weakens the ability of Salmonella enterica serovar Typhi to survive in macrophages by increasing intracellular ATP levels. Microb Pathog 2018; 115:321-331. [PMID: 29306008 DOI: 10.1016/j.micpath.2017.12.072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Revised: 11/29/2017] [Accepted: 12/30/2017] [Indexed: 10/18/2022]
Abstract
Bacterial non-coding RNAs (ncRNAs), as important regulatory factors, are involved in many cellular processes, including virulence and protection against environmental stress. The 5' untranslated region (UTR) of malS (named malS-5'UTR), a regulatory ncRNA, increases the invasive capacity and influences histidine biosynthesis in Salmonella enterica serovar Typhi (S. Typhi). In this study, we found that overexpression of the malS-5'UTR decreased S. Typhi survival within macrophages. A microarray analysis of a strain overexpressing the malS-5'UTR revealed a significant increase in the mRNA levels of the atp operon. The intracellular ATP levels were elevated in the malS-5'UTR overexpression strain. Quantitative real-time polymerase chain reaction results showed that the malS-5'UTR downregulated the mRNA levels of phoP, phoQ, and mgtC. MgtC, its expression is regulated by PhoP/PhoQ two-component regulatory system, inhibits the F1F0 ATP synthase, thereby preventing the accumulation of ATP to non-physiological levels and the acidification of the cytoplasm within macrophages. Thus, we propose that the malS-5'UTR weakens the ability of S. Typhi to survive in macrophages, probably because of the accumulation of ATP within macrophages, by regulating the mRNA levels of mgtC and the atp operon in a phoP-dependent manner.
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Affiliation(s)
- Fang Dong
- Department of Biochemistry and Molecular Biology, Jiangsu University School of Medicine, Zhenjiang, Jiangsu 212013, China
| | - Lin Xia
- Department of Clinical Laboratory, Affiliated Hospital, Jiangsu University, Zhenjiang, Jiangsu 212001, China
| | - Renfei Lu
- Department of Biochemistry and Molecular Biology, Jiangsu University School of Medicine, Zhenjiang, Jiangsu 212013, China
| | - Xin Zhao
- Department of Biochemistry and Molecular Biology, Jiangsu University School of Medicine, Zhenjiang, Jiangsu 212013, China
| | - Yiquan Zhang
- Department of Biochemistry and Molecular Biology, Jiangsu University School of Medicine, Zhenjiang, Jiangsu 212013, China
| | - Ying Zhang
- Department of Biochemistry and Molecular Biology, Jiangsu University School of Medicine, Zhenjiang, Jiangsu 212013, China.
| | - Xinxiang Huang
- Department of Biochemistry and Molecular Biology, Jiangsu University School of Medicine, Zhenjiang, Jiangsu 212013, China.
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24
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VanCleave TT, Pulsifer AR, Connor MG, Warawa JM, Lawrenz MB. Impact of Gentamicin Concentration and Exposure Time on Intracellular Yersinia pestis. Front Cell Infect Microbiol 2017; 7:505. [PMID: 29312891 PMCID: PMC5732358 DOI: 10.3389/fcimb.2017.00505] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 11/22/2017] [Indexed: 11/27/2022] Open
Abstract
The study of intracellular bacterial pathogens in cell culture hinges on inhibiting extracellular growth of the bacteria in cell culture media. Aminoglycosides, like gentamicin, were originally thought to poorly penetrate eukaryotic cells, and thus, while inhibiting extracellular bacteria, these antibiotics had limited effect on inhibiting the growth of intracellular bacteria. This property led to the development of the antibiotic protection assay to study intracellular pathogens in vitro. More recent studies have demonstrated that aminoglycosides slowly penetrate eukaryotic cells and can even reach intracellular concentrations that inhibit intracellular bacteria. Therefore, important considerations, such as antibiotic concentration, incubation time, and cell type need to be made when designing the antibiotic protection assay to avoid potential false positive/negative observations. Yersinia pestis, which causes the human disease known as the plague, is a facultative intracellular pathogen that can infect and replicate in macrophages. Y. pestis is sensitive to gentamicin and this antibiotic is often employed in the antibiotic protection assay to study the Y. pestis intracellular life cycle. However, a large variety of gentamicin concentrations and incubation periods have been reported in the Y. pestis literature without a clear characterization of the potential influences that variations in the gentamicin protection assay could have on intracellular growth of this pathogen. This raised concerns that variations in the gentamicin protection assay could influence phenotypes and reproducibility of data. To provide a better understanding of the potential consequences that variations in the gentamicin protection assay could have on Y. pestis, we systematically examined the impact of multiple variables of the gentamicin protection assay on Y. pestis intracellular survival in macrophages. We found that prolonged incubation periods with low concentrations of gentamicin, or short incubation periods with higher concentrations of the antibiotic, have a dramatic impact on intracellular growth. Furthermore, the degree of sensitivity of intracellular Y. pestis to gentamicin was also cell type dependent. These data highlight the importance to empirically establish cell type specific gentamicin protection assays to avoid potential artificial data in Y. pestis intracellular studies.
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Affiliation(s)
- Tiva T VanCleave
- Department of Microbiology and Immunology and Center for Predictive Medicine for Biodefense and Emerging Infectious Diseases, University of Louisville School of Medicine, Louisville, KY, United States
| | - Amanda R Pulsifer
- Department of Microbiology and Immunology and Center for Predictive Medicine for Biodefense and Emerging Infectious Diseases, University of Louisville School of Medicine, Louisville, KY, United States
| | - Michael G Connor
- Department of Microbiology and Immunology and Center for Predictive Medicine for Biodefense and Emerging Infectious Diseases, University of Louisville School of Medicine, Louisville, KY, United States
| | - Jonathan M Warawa
- Department of Microbiology and Immunology and Center for Predictive Medicine for Biodefense and Emerging Infectious Diseases, University of Louisville School of Medicine, Louisville, KY, United States
| | - Matthew B Lawrenz
- Department of Microbiology and Immunology and Center for Predictive Medicine for Biodefense and Emerging Infectious Diseases, University of Louisville School of Medicine, Louisville, KY, United States
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25
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Induction of Type I Interferon through a Noncanonical Toll-Like Receptor 7 Pathway during Yersinia pestis Infection. Infect Immun 2017; 85:IAI.00570-17. [PMID: 28847850 PMCID: PMC5649010 DOI: 10.1128/iai.00570-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 08/21/2017] [Indexed: 12/12/2022] Open
Abstract
Yersinia pestis causes bubonic, pneumonic, and septicemic plague, diseases that are rapidly lethal to most mammals, including humans. Plague develops as a consequence of bacterial neutralization of the host's innate immune response, which permits uncontrolled growth and causes the systemic hyperactivation of the inflammatory response. We previously found that host type I interferon (IFN) signaling is induced during Y. pestis infection and contributes to neutrophil depletion and disease. In this work, we show that type I IFN expression is derived from the recognition of intracellular Y. pestis by host Toll-like receptor 7 (TLR7). Type I IFN expression proceeded independent of myeloid differentiation factor 88 (MyD88), which is the only known signaling adaptor for TLR7, suggesting that a noncanonical mechanism occurs in Y. pestis-infected macrophages. In the murine plague model, TLR7 was a significant contributor to the expression of serum IFN-β, whereas MyD88 was not. Furthermore, like the type I IFN response, TLR7 contributed to the lethality of septicemic plague and was associated with the suppression of neutrophilic inflammation. In contrast, TLR7 was important for defense against disease in the lungs. Together, these data demonstrate that an atypical TLR7 signaling pathway contributes to type I IFN expression during Y. pestis infection and suggest that the TLR7-driven type I IFN response plays an important role in determining the outcome of plague.
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26
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Ilyas B, Tsai CN, Coombes BK. Evolution of Salmonella-Host Cell Interactions through a Dynamic Bacterial Genome. Front Cell Infect Microbiol 2017; 7:428. [PMID: 29034217 PMCID: PMC5626846 DOI: 10.3389/fcimb.2017.00428] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 09/19/2017] [Indexed: 11/13/2022] Open
Abstract
Salmonella Typhimurium has a broad arsenal of genes that are tightly regulated and coordinated to facilitate adaptation to the various host environments it colonizes. The genome of Salmonella Typhimurium has undergone multiple gene acquisition events and has accrued changes in non-coding DNA that have undergone selection by regulatory evolution. Together, at least 17 horizontally acquired pathogenicity islands (SPIs), prophage-associated genes, and changes in core genome regulation contribute to the virulence program of Salmonella. Here, we review the latest understanding of these elements and their contributions to pathogenesis, emphasizing the regulatory circuitry that controls niche-specific gene expression. In addition to an overview of the importance of SPI-1 and SPI-2 to host invasion and colonization, we describe the recently characterized contributions of other SPIs, including the antibacterial activity of SPI-6 and adhesion and invasion mediated by SPI-4. We further discuss how these fitness traits have been integrated into the regulatory circuitry of the bacterial cell through cis-regulatory evolution and by a careful balance of silencing and counter-silencing by regulatory proteins. Detailed understanding of regulatory evolution within Salmonella is uncovering novel aspects of infection biology that relate to host-pathogen interactions and evasion of host immunity.
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Affiliation(s)
- Bushra Ilyas
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada.,Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
| | - Caressa N Tsai
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada.,Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
| | - Brian K Coombes
- Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
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27
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Yersinia pestis Resists Predation by Acanthamoeba castellanii and Exhibits Prolonged Intracellular Survival. Appl Environ Microbiol 2017; 83:AEM.00593-17. [PMID: 28455335 DOI: 10.1128/aem.00593-17] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Accepted: 04/10/2017] [Indexed: 12/13/2022] Open
Abstract
Plague is a flea-borne rodent-associated zoonotic disease caused by Yersinia pestis The disease is characterized by epizootics with high rodent mortalities, punctuated by interepizootic periods when the bacterium persists in an unknown reservoir. This study investigates the interaction between Y. pestis and the ubiquitous soil free-living amoeba (FLA) Acanthamoeba castellanii to assess if the bacterium can survive within soil amoebae and whether intracellular mechanisms are conserved between infection of mammalian macrophages and soil amoebae. The results demonstrate that during coculture with amoebae, representative Y. pestis strains of epidemic biovars Medievalis, Orientalis, and Antiqua are phagocytized and able to survive within amoebae for at least 5 days. Key Y. pestis determinants of the intracellular interaction of Y. pestis and phagocytic macrophages, PhoP and the type three secretion system (T3SS), were then tested for their roles in the Y. pestis-amoeba interaction. Consistent with a requirement for the PhoP transcriptional activator in the intracellular survival of Y. pestis in macrophages, a PhoP mutant is unable to survive when cocultured with amoebae. Additionally, induction of the T3SS blocks phagocytic uptake of Y. pestis by amoebae, similar to that which occurs during macrophage infection. Electron microscopy revealed that in A. castellanii, Y. pestis resides intact within spacious vacuoles which were characterized using lysosomal trackers as being separated from the lysosomal compartment. This evidence for prolonged survival and subversion of intracellular digestion of Y. pestis within FLA suggests that protozoa may serve as a protective soil reservoir for Y. pestisIMPORTANCEYersinia pestis is a reemerging flea-borne zoonotic disease. Sylvatic plague cycles are characterized by an epizootic period during which the disease spreads rapidly, causing high rodent mortality, and an interepizootic period when the bacterium quiescently persists in an unknown reservoir. An understanding of the ecology of Y. pestis in the context of its persistence in the environment and its reactivation to initiate a new epizootic cycle is key to implementing novel surveillance strategies to more effectively predict and prevent new disease outbreaks. Here, we demonstrate prolonged survival and subversion of intracellular digestion of Y. pestis within a soil free-living amoeba. This suggests the potential role for protozoa as a protective soil reservoir for Y. pestis, which may help explain the recrudescence of plague epizootics.
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28
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Nam D, Choi E, Shin D, Lee EJ. tRNA Pro -mediated downregulation of elongation factor P is required for mgtCBR expression during Salmonella infection. Mol Microbiol 2016; 102:221-232. [PMID: 27350030 DOI: 10.1111/mmi.13454] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/27/2016] [Indexed: 12/31/2022]
Abstract
Bacterial ribosome requires elongation factor P to translate fragments harbouring consecutive proline codons. Given the abundance of ORFs with potential EF-P regulated sites, EF-P was assumed to be constitutively expressed. Here, we report that the intracellular pathogen Salmonella enterica serovar Typhimurium decreases efp mRNA levels during course of infection. We determined that the decrease in efp mRNA is triggered by low levels of charged tRNAPro , a condition that Salmonella experiences when inside a macrophage phagosome. Surprisingly, downregulation of EF-P selectively promotes expression of the virulence mgtC gene and contributes to Salmonella's ability to survive inside macrophages. The decrease in EF-P levels induces ribosome stalling at the consecutive proline codons of the mgtP open reading frame in the mgtCBR leader RNA, and thus allows formation of a stem-loop structure promoting transcription of the mgtC gene. The substitution of proline codons in the mgtP gene eliminates EF-P-mediated mgtC expression and thus Salmonella's survival inside macrophages. Our findings indicate that Salmonella benefits virulence genes by decreasing EF-P levels and inducing the stringent response inside host.
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Affiliation(s)
- Daesil Nam
- Division of Microbiology, Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, 16419, South Korea
| | - Eunna Choi
- Department of Genetic Engineering and Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Yongin, 17104, South Korea
| | - Dongwoo Shin
- Division of Microbiology, Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, 16419, South Korea
| | - Eun-Jin Lee
- Department of Genetic Engineering and Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Yongin, 17104, South Korea.
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29
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Belon C, Blanc-Potard AB. Intramacrophage Survival for Extracellular Bacterial Pathogens: MgtC As a Key Adaptive Factor. Front Cell Infect Microbiol 2016; 6:52. [PMID: 27242970 PMCID: PMC4869558 DOI: 10.3389/fcimb.2016.00052] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 04/26/2016] [Indexed: 01/06/2023] Open
Affiliation(s)
- Claudine Belon
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier (DIMNP Centre National de la Recherche Scientifique-UMR5235) Montpellier, France
| | - Anne-Béatrice Blanc-Potard
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier (DIMNP Centre National de la Recherche Scientifique-UMR5235) Montpellier, France
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30
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Liu L, Fang H, Yang H, Zhang Y, Han Y, Zhou D, Yang R. CRP Is an Activator of Yersinia pestis Biofilm Formation that Operates via a Mechanism Involving gmhA and waaAE-coaD. Front Microbiol 2016; 7:295. [PMID: 27014218 PMCID: PMC4782182 DOI: 10.3389/fmicb.2016.00295] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 02/23/2016] [Indexed: 01/28/2023] Open
Abstract
gmhA encodes a phosphoheptose isomerase that catalyzes the biosynthesis of heptose, a conserved component of lipopolysaccharide (LPS). GmhA plays an important role in Yersinia pestis biofilm blockage in the flea gut. waaA, waaE, and coaD constitute a three-gene operon waaAE-coaD in Y. pestis. waaA encodes a transferase that is responsible for binding lipid-A to the core oligosaccharide of LPS. WaaA is a key determinant in Y. pestis biofilm formation, and the waaA expression is positively regulated by the two-component regulatory system PhoP/PhoQ. WaaE is involved in LPS modification and is necessary for Y. pestis biofilm production. In this study, the biofilm-related phenotypic assays indicate that the global regulator CRP stimulates Y. pestis biofilm formation in vitro and on nematodes, while it has no regulatory effect on the biosynthesis of the biofilm-signaling molecular 3',5'-cyclic diguanosine monophosphate. Further gene regulation experiments disclose that CRP does not regulate the hms genes at the transcriptional level but directly promotes the gmhA transcription and indirectly activates the waaAE-coaD transcription through directly acting on phoPQ-YPO1632. Thus, it is speculated that CRP-mediated carbon catabolite regulation of Y. pestis biofilm formation depends on the CRP-dependent carbon source metabolic pathways of the biosynthesis, modification, and transportation of biofilm exopolysaccharide.
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Affiliation(s)
- Lei Liu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
| | - Haihong Fang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
| | - Huiying Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
| | - Yiquan Zhang
- Department of Biochemistry, School of Medicine, Jiangsu University Zhenjiang, China
| | - Yanping Han
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
| | - Dongsheng Zhou
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
| | - Ruifu Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
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31
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Chen S, Thompson KM, Francis MS. Environmental Regulation of Yersinia Pathophysiology. Front Cell Infect Microbiol 2016; 6:25. [PMID: 26973818 PMCID: PMC4773443 DOI: 10.3389/fcimb.2016.00025] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 02/15/2016] [Indexed: 12/26/2022] Open
Abstract
Hallmarks of Yersinia pathogenesis include the ability to form biofilms on surfaces, the ability to establish close contact with eukaryotic target cells and the ability to hijack eukaryotic cell signaling and take over control of strategic cellular processes. Many of these virulence traits are already well-described. However, of equal importance is knowledge of both confined and global regulatory networks that collaborate together to dictate spatial and temporal control of virulence gene expression. This review has the purpose to incorporate historical observations with new discoveries to provide molecular insight into how some of these regulatory mechanisms respond rapidly to environmental flux to govern tight control of virulence gene expression by pathogenic Yersinia.
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Affiliation(s)
- Shiyun Chen
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences Wuhan, China
| | - Karl M Thompson
- Department of Microbiology, College of Medicine, Howard University Washington, DC, USA
| | - Matthew S Francis
- Umeå Centre for Microbial Research, Umeå UniversityUmeå, Sweden; Department of Molecular Biology, Umeå UniversityUmeå, Sweden
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32
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Belon C, Rosas Olvera M, Vives E, Kremer L, Gannoun-Zaki L, Blanc-Potard AB. Use of the Salmonella MgtR peptide as an antagonist of the Mycobacterium MgtC virulence factor. Future Microbiol 2016; 11:215-25. [DOI: 10.2217/fmb.15.134] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Background: The MgtC virulence factor has been proposed as an attractive target for antivirulence strategies because it is shared by several important bacterial pathogens, including Salmonella enterica and Mycobacterium tuberculosis (Mtb). Aim: A natural antagonistic peptide, MgtR, which interacts with MgtC and modulates its stability, has been identified in Salmonella, and we investigated its efficiency to target MgtC in another pathogen. Materials & methods: We evaluated the interaction between Salmonella MgtR peptide and the Mtb MgtC protein using an in vivo bacterial two-hybrid system and we addressed the effect of exogenously added synthetic MgtR and endogenously expressed peptide. Results: MgtR peptide strongly interacted with Mtb MgtC protein and exogenously added synthetic MgtR peptide-reduced Mtb MgtC level and interfered with the dimerization of Mtb MgtC. Importantly, heterologous expression of MgtR in Mycobacterium bovis BCG resulted in increased phagocytosis and reduced intramacrophage survival. Conclusion: MgtR peptide can target Mtb MgtC protein and reduce mycobacterial macrophage resistance, thus providing a promising new scaffold for the development of antivirulence compounds.
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Affiliation(s)
- Claudine Belon
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France
- CNRS, UMR5235, 34095 Montpellier Cedex 05, France
| | - Mariana Rosas Olvera
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France
- CNRS, UMR5235, 34095 Montpellier Cedex 05, France
| | - Eric Vives
- Université de Montpellier, Montpellier, F-34090, France
| | - Laurent Kremer
- INSERM, DIMNP, CNRS-UMR5235, Montpellier, France
- Centre d’études d'agents Pathogènes et Biotechnologies pour la Santé (CPBS - FRE 3689), 1919 route de Mende, 34293 Montpellier, France
| | - Laila Gannoun-Zaki
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France
- CNRS, UMR5235, 34095 Montpellier Cedex 05, France
| | - Anne-Béatrice Blanc-Potard
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France
- CNRS, UMR5235, 34095 Montpellier Cedex 05, France
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Abstract
Y. pestis exhibits dramatically different traits of pathogenicity and transmission, albeit their close genetic relationship with its ancestor-Y. pseudotuberculosis, a self-limiting gastroenteric pathogen. Y. pestis is evolved into a deadly pathogen and transmitted to mammals and/or human beings by infected flea biting or directly contacting with the infected animals. Various kinds of environmental changes are implicated into its complex life cycle and pathogenesis. Dynamic regulation of gene expression is critical for environmental adaptation or survival, primarily reflected by genetic regulation mediated by transcriptional factors and small regulatory RNAs at the transcriptional and posttranscriptional level, respectively. The effects of genetic regulation have been shown to profoundly influence Y. pestis physiology and pathogenesis such as stress resistance, biofilm formation, intracellular survival, and replication. In this chapter, we mainly summarize the progresses on popular methods of genetic regulation and on regulatory patterns and consequences of many key transcriptional and posttranscriptional regulators, with a particular emphasis on how genetic regulation influences the biofilm and virulence of Y. pestis.
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34
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Role of Tellurite Resistance Operon in Filamentous Growth of Yersinia pestis in Macrophages. PLoS One 2015; 10:e0141984. [PMID: 26536670 PMCID: PMC4633105 DOI: 10.1371/journal.pone.0141984] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 10/15/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Yersinia pestis initiates infection by parasitism of host macrophages. In response to macrophage infections, intracellular Y. pestis can assume a filamentous cellular morphology which may mediate resistance to host cell innate immune responses. We previously observed the expression of Y. pestis tellurite resistance proteins TerD and TerE from the terZABCDE operon during macrophage infections. Others have observed a filamentous response associated with expression of tellurite resistance operon in Escherichia coli exposed to tellurite. Therefore, in this study we examine the potential role of Y. pestis tellurite resistance operon in filamentous cellular morphology during macrophage infections. PRINCIPAL FINDINGS In vitro treatment of Y. pestis culture with sodium tellurite (Na2TeO3) caused the bacterial cells to assume a filamentous phenotype similar to the filamentous phenotype observed during macrophage infections. A deletion mutant for genes terZAB abolished the filamentous morphologic response to tellurite exposure or intracellular parasitism, but without affecting tellurite resistance. However, a terZABCDE deletion mutant abolished both filamentous morphologic response and tellurite resistance. Complementation of the terZABCDE deletion mutant with terCDE, but not terZAB, partially restored tellurite resistance. When the terZABCDE deletion mutant was complemented with terZAB or terCDE, Y. pestis exhibited filamentous morphology during macrophage infections as well as while these complemented genes were being expressed under an in vitro condition. Further in E. coli, expression of Y. pestis terZAB, but not terCDE, conferred a filamentous phenotype. CONCLUSIONS These findings support the role of Y. pestis terZAB mediation of the filamentous response phenotype; whereas, terCDE confers tellurite resistance. Although the beneficial role of filamentous morphological responses by Y. pestis during macrophage infections is yet to be fully defined, it may be a bacterial adaptive strategy to macrophage associated stresses.
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Connor MG, Pulsifer AR, Price CT, Abu Kwaik Y, Lawrenz MB. Yersinia pestis Requires Host Rab1b for Survival in Macrophages. PLoS Pathog 2015; 11:e1005241. [PMID: 26495854 PMCID: PMC4619670 DOI: 10.1371/journal.ppat.1005241] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 09/30/2015] [Indexed: 11/18/2022] Open
Abstract
Yersinia pestis is a facultative intracellular pathogen that causes the disease known as plague. During infection of macrophages Y. pestis actively evades the normal phagosomal maturation pathway to establish a replicative niche within the cell. However, the mechanisms used by Y. pestis to subvert killing by the macrophage are unknown. Host Rab GTPases are central mediators of vesicular trafficking and are commonly targeted by bacterial pathogens to alter phagosome maturation and killing by macrophages. Here we demonstrate for the first time that host Rab1b is required for Y. pestis to effectively evade killing by macrophages. We also show that Rab1b is specifically recruited to the Yersinia containing vacuole (YCV) and that Y. pestis is unable to subvert YCV acidification when Rab1b expression is knocked down in macrophages. Furthermore, Rab1b knockdown also altered the frequency of association between the YCV with the lysosomal marker Lamp1, suggesting that Rab1b recruitment to the YCV directly inhibits phagosome maturation. Finally, we show that Rab1b knockdown also impacts the pH of the Legionella pneumophila containing vacuole, another pathogen that recruits Rab1b to its vacuole. Together these data identify a novel role for Rab1b in the subversion of phagosome maturation by intracellular pathogens and suggest that recruitment of Rab1b to the pathogen containing vacuole may be a conserved mechanism to control vacuole pH. Yersinia pestis is the bacterial agent that causes the human disease known as plague. While often considered a historic disease, Y. pestis is endemic in rodent populations on several continents and the World Health Organization considers plague to be a reemerging disease. Much of the success of this pathogen comes from its ability to evade clearance by the innate immune system of its host. One weapon in the Y. pestis arsenal is its ability to resist killing when engulfed by macrophages. Upon invasion of macrophages, Y. pestis actively manipulates the cell to generate a protective vacuolar compartment, called the Yersinia containing vacuole (YCV) that allows the bacterium to evade the normal pathogen killing mechanisms of the macrophage. Here we demonstrate that the host protein Rab1b is recruited to the YCV and is required for Y. pestis to inhibit both the acidification and normal maturation of the phagosome to establish a protective niche within the cell. Rab1b is the first protein, either from the host or Y. pestis, shown to contribute to the biogenesis of the YCV. Furthermore, our data suggest a previously unknown impact of Rab1b recruitment in the phagosome maturation pathway.
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Affiliation(s)
- Michael G. Connor
- Department of Microbiology and Immunology and the Center for Predictive Medicine for Biodefense and Emerging Infectious Diseases, University of Louisville School of Medicine, Louisville, Kentucky, United States of America
| | - Amanda R. Pulsifer
- Department of Microbiology and Immunology and the Center for Predictive Medicine for Biodefense and Emerging Infectious Diseases, University of Louisville School of Medicine, Louisville, Kentucky, United States of America
| | - Christopher T. Price
- Department of Microbiology and Immunology and the Center for Predictive Medicine for Biodefense and Emerging Infectious Diseases, University of Louisville School of Medicine, Louisville, Kentucky, United States of America
| | - Yousef Abu Kwaik
- Department of Microbiology and Immunology and the Center for Predictive Medicine for Biodefense and Emerging Infectious Diseases, University of Louisville School of Medicine, Louisville, Kentucky, United States of America
| | - Matthew B. Lawrenz
- Department of Microbiology and Immunology and the Center for Predictive Medicine for Biodefense and Emerging Infectious Diseases, University of Louisville School of Medicine, Louisville, Kentucky, United States of America
- * E-mail:
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Erhardt M, Dersch P. Regulatory principles governing Salmonella and Yersinia virulence. Front Microbiol 2015; 6:949. [PMID: 26441883 PMCID: PMC4563271 DOI: 10.3389/fmicb.2015.00949] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 08/27/2015] [Indexed: 11/13/2022] Open
Abstract
Enteric pathogens such as Salmonella and Yersinia evolved numerous strategies to survive and proliferate in different environmental reservoirs and mammalian hosts. Deciphering common and pathogen-specific principles for how these bacteria adjust and coordinate spatiotemporal expression of virulence determinants, stress adaptation, and metabolic functions is fundamental to understand microbial pathogenesis. In order to manage sudden environmental changes, attacks by the host immune systems and microbial competition, the pathogens employ a plethora of transcriptional and post-transcriptional control elements, including transcription factors, sensory and regulatory RNAs, RNAses, and proteases, to fine-tune and control complex gene regulatory networks. Many of the contributing global regulators and the molecular mechanisms of regulation are frequently conserved between Yersinia and Salmonella. However, the interplay, arrangement, and composition of the control elements vary between these closely related enteric pathogens, which generate phenotypic differences leading to distinct pathogenic properties. In this overview we present common and different regulatory networks used by Salmonella and Yersinia to coordinate the expression of crucial motility, cell adhesion and invasion determinants, immune defense strategies, and metabolic adaptation processes. We highlight evolutionary changes of the gene regulatory circuits that result in different properties of the regulatory elements and how this influences the overall outcome of the infection process.
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Affiliation(s)
- Marc Erhardt
- Young Investigator Group Infection Biology of Salmonella, Helmholtz Centre for Infection Research Braunschweig, Germany
| | - Petra Dersch
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research Braunschweig, Germany
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Bahnan W, Boettner DR, Westermark L, Fällman M, Schesser K. Pathogenic Yersinia Promotes Its Survival by Creating an Acidic Fluid-Accessible Compartment on the Macrophage Surface. PLoS One 2015; 10:e0133298. [PMID: 26275291 PMCID: PMC4537277 DOI: 10.1371/journal.pone.0133298] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 06/25/2015] [Indexed: 11/29/2022] Open
Abstract
Microbial pathogens and host immune cells each initiate events following their interaction in an attempt to drive the outcome to their respective advantage. Here we show that the bacterial pathogen Yersinia pseudotuberculosis sustains itself on the surface of a macrophage by forming acidic fluid-accessible compartments that are partially bounded by the host cell plasma membrane. These Yersinia-containing acidic compartments (YACs) are bereft of the early endosomal marker EEA1 and the lysosomal antigen LAMP1 and readily form on primary macrophages as well as macrophage-like cell lines. YAC formation requires the presence of the Yersinia virulence plasmid which encodes a type III secretion system. Unexpectedly, we found that the initial formation of YACs did not require translocation of the type III effectors into the host cell cytosol; however, the duration of YACs was markedly greater in infections using translocation-competent Y. pseudotuberculosis strains as well as strains expressing the effector YopJ. Furthermore, it was in this translocation- and YopJ-dependent phase of infection that the acidic environment was critical for Y. pseudotuberculosis survival during its interaction with macrophages. Our findings indicate that during its extracellular phase of infection Y. pseudotuberculosis initiates and then, by a separate mechanism, stabilizes the formation of a highly intricate structure on the surface of the macrophage that is disengaged from the endocytic pathway.
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Affiliation(s)
- Wael Bahnan
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Douglas R. Boettner
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | | | - Maria Fällman
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Kurt Schesser
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
- * E-mail:
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38
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Regulation and function of the Salmonella MgtC virulence protein. J Microbiol 2015; 53:667-72. [DOI: 10.1007/s12275-015-5283-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 07/02/2015] [Accepted: 07/03/2015] [Indexed: 10/23/2022]
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When Too Much ATP Is Bad for Protein Synthesis. J Mol Biol 2015; 427:2586-2594. [PMID: 26150063 DOI: 10.1016/j.jmb.2015.06.021] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 06/30/2015] [Accepted: 06/30/2015] [Indexed: 01/17/2023]
Abstract
Adenosine triphosphate (ATP) is the energy currency of living cells. Even though ATP powers virtually all energy-dependent activities, most cellular ATP is utilized in protein synthesis via tRNA aminoacylation and guanosine triphosphate regeneration. Magnesium (Mg(2+)), the most common divalent cation in living cells, plays crucial roles in protein synthesis by maintaining the structure of ribosomes, participating in the biochemistry of translation initiation and functioning as a counterion for ATP. A non-physiological increase in ATP levels hinders growth in cells experiencing Mg(2+) limitation because ATP is the most abundant nucleotide triphosphate in the cell, and Mg(2+) is also required for the stabilization of the cytoplasmic membrane and as a cofactor for essential enzymes. We propose that organisms cope with Mg(2+) limitation by decreasing ATP levels and ribosome production, thereby reallocating Mg(2+) to indispensable cellular processes.
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40
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Belon C, Soscia C, Bernut A, Laubier A, Bleves S, Blanc-Potard AB. A Macrophage Subversion Factor Is Shared by Intracellular and Extracellular Pathogens. PLoS Pathog 2015; 11:e1004969. [PMID: 26080006 PMCID: PMC4469704 DOI: 10.1371/journal.ppat.1004969] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 05/21/2015] [Indexed: 01/03/2023] Open
Abstract
Pathogenic bacteria have developed strategies to adapt to host environment and resist host immune response. Several intracellular bacterial pathogens, including Salmonella enterica and Mycobacterium tuberculosis, share the horizontally-acquired MgtC virulence factor that is important for multiplication inside macrophages. MgtC is also found in pathogenic Pseudomonas species. Here we investigate for the first time the role of MgtC in the virulence of an extracellular pathogen, Pseudomonas aeruginosa. A P. aeruginosa mgtC mutant is attenuated in the systemic infection model of zebrafish embryos, and strikingly, the attenuated phenotype is dependent on the presence of macrophages. In ex vivo experiments, the P. aeruginosa mgtC mutant is more sensitive to macrophage killing than the wild-type strain. However, wild-type and mutant strains behave similarly toward macrophage killing when macrophages are treated with an inhibitor of the vacuolar proton ATPase. Importantly, P. aeruginosa mgtC gene expression is strongly induced within macrophages and phagosome acidification contributes to an optimal expression of the gene. Thus, our results support the implication of a macrophage intracellular stage during P. aeruginosa acute infection and suggest that Pseudomonas MgtC requires phagosome acidification to play its intracellular role. Moreover, we demonstrate that P. aeruginosa MgtC is required for optimal growth in Mg2+ deprived medium, a property shared by MgtC factors from intracellular pathogens and, under Mg2+ limitation, P. aeruginosa MgtC prevents biofilm formation. We propose that MgtC shares a similar function in intracellular and extracellular pathogens, which contributes to macrophage resistance and fine-tune adaptation to host immune response in relation to the different bacterial lifestyles. In addition, the phenotypes observed with the mgtC mutant in infection models can be mimicked in wild-type P. aeruginosa strain by producing a MgtC antagonistic peptide, thus highlighting MgtC as a promising new target for anti-virulence strategies. Pathogenic bacteria have to resist host immune response and MgtC is used by several intracellular pathogens to promote bacterial multiplication inside macrophages. Here we investigated MgtC’s role in the virulence of an extracellular pathogen, Pseudomonas aeruginosa. A P. aeruginosa mgtC mutant is attenuated in zebrafish embryos, but only in the presence of macrophages. Moreover, this mutant is more rapidly killed by macrophages than the wild-type strain. Both phenotypes can be mimicked upon production of a MgtC antagonistic peptide in wild-type Pseudomonas strain. MgtC thus provides a singular example of a virulence determinant that promotes strategies to subvert the antimicrobial behavior of macrophages, in both intracellular and extracellular pathogens and our results support an intramacrophage stage during in P. aeruginosa acute infection, as well as an interplay between MgtC role and phagosome acidification. In addition, P. aeruginosa MgtC is required for growth in Mg2+ deprived medium, a property shared by MgtC factors from intracellular pathogens, and limits biofilm formation. MgtC may share a similar function in intracellular and extracellular pathogens, with an outcome adapted to the different bacterial lifestyles
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Affiliation(s)
- Claudine Belon
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS-UMR5235, Montpellier, France
| | - Chantal Soscia
- CNRS & Aix-Marseille Université, Laboratoire d’Ingénierie des Systèmes Macromoléculaires (UMR7255), Marseille, France
| | - Audrey Bernut
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS-UMR5235, Montpellier, France
| | - Aurélie Laubier
- CNRS & Aix-Marseille Université, Laboratoire d’Ingénierie des Systèmes Macromoléculaires (UMR7255), Marseille, France
| | - Sophie Bleves
- CNRS & Aix-Marseille Université, Laboratoire d’Ingénierie des Systèmes Macromoléculaires (UMR7255), Marseille, France
- * E-mail: (SB); (ABBP)
| | - Anne-Béatrice Blanc-Potard
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS-UMR5235, Montpellier, France
- * E-mail: (SB); (ABBP)
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41
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Salmonella promotes virulence by repressing cellulose production. Proc Natl Acad Sci U S A 2015; 112:5183-8. [PMID: 25848006 DOI: 10.1073/pnas.1500989112] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cellulose is the most abundant organic polymer on Earth. In bacteria, cellulose confers protection against environmental insults and is a constituent of biofilms typically formed on abiotic surfaces. We report that, surprisingly, Salmonella enterica serovar Typhimurium makes cellulose when inside macrophages. We determine that preventing cellulose synthesis increases virulence, whereas stimulation of cellulose synthesis inside macrophages decreases virulence. An attenuated mutant lacking the mgtC gene exhibited increased cellulose levels due to increased expression of the cellulose synthase gene bcsA and of cyclic diguanylate, the allosteric activator of the BcsA protein. Inactivation of bcsA restored wild-type virulence to the Salmonella mgtC mutant, but not to other attenuated mutants displaying a wild-type phenotype regarding cellulose. Our findings indicate that a virulence determinant can promote pathogenicity by repressing a pathogen's antivirulence trait. Moreover, they suggest that controlling antivirulence traits increases long-term pathogen fitness by mediating a trade-off between acute virulence and transmission.
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42
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Vadyvaloo V, Viall AK, Jarrett CO, Hinz AK, Sturdevant DE, Joseph Hinnebusch B. Role of the PhoP-PhoQ gene regulatory system in adaptation of Yersinia pestis to environmental stress in the flea digestive tract. MICROBIOLOGY-SGM 2015; 161:1198-1210. [PMID: 25804213 PMCID: PMC4635514 DOI: 10.1099/mic.0.000082] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The Yersinia pestis PhoPQ gene regulatory system is induced during infection of the flea digestive tract and is required to produce adherent biofilm in the foregut, which greatly enhances bacterial transmission during a flea bite. To understand the in vivo context of PhoPQ induction and to determine PhoP-regulated targets in the flea, we undertook whole-genome comparative transcriptional profiling of Y. pestis WT and ΔphoP strains isolated from infected fleas and from temperature-matched in vitro planktonic and flow-cell biofilm cultures. In the absence of PhoP regulation, the gene expression program indicated that the bacteria experienced diverse physiological stresses and were in a metabolically less active state. Multiple stress response genes, including several toxin–antitoxin loci and YhcN family genes responsible for increased acid tolerance, were upregulated in the phoP mutant during flea infection. The data implied that PhoPQ was induced by low pH in the flea gut, and that PhoP modulated physiological adaptation to acid and other stresses encountered during infection of the flea. This adaptive response, together with PhoP-dependent modification of the bacterial outer surface that includes repression of pH 6 antigen fimbriae, supports stable biofilm development in the flea foregut.
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Affiliation(s)
- Viveka Vadyvaloo
- 1Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA, 99164, USA
| | - Austin K Viall
- 2Plague Section, Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Clayton O Jarrett
- 2Plague Section, Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Angela K Hinz
- 1Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA, 99164, USA
| | - Daniel E Sturdevant
- 3Genomics Unit, Research Technologies Section, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA
| | - B Joseph Hinnebusch
- 2Plague Section, Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA
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Belon C, Gannoun-Zaki L, Lutfalla G, Kremer L, Blanc-Potard AB. Mycobacterium marinum MgtC plays a role in phagocytosis but is dispensable for intracellular multiplication. PLoS One 2014; 9:e116052. [PMID: 25545682 PMCID: PMC4278808 DOI: 10.1371/journal.pone.0116052] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 12/04/2014] [Indexed: 01/04/2023] Open
Abstract
MgtC is a virulence factor involved in intramacrophage growth that has been reported in several intracellular pathogens, including Mycobacterium tuberculosis and Salmonella enterica serovar Typhimurium. MgtC participates also in adaptation to Mg2+ deprivation. Herein, we have constructed a mgtC mutant in Mycobacterium marinum to further investigate the role of MgtC in mycobacteria. We show that the M. marinum mgtC gene (Mma mgtC) is strongly induced upon Mg2+ deprivation and is required for optimal growth in Mg2+-deprived medium. The behaviour of the Mma mgtC mutant has been investigated in the Danio rerio infection model using a transgenic reporter zebrafish line that specifically labels neutrophils. Although the mgtC mutant is not attenuated in the zebrafish embryo model based on survival curves, our results indicate that phagocytosis by neutrophils is enhanced with the mgtC mutant compared to the wild-type strain following subcutaneous injection. Increased phagocytosis of the mutant strain is also observed ex vivo with the murine J774 macrophage cell line. On the other hand, no difference was found between the mgtC mutant and the wild-type strain in bacterial adhesion to macrophages and in the internalization into epithelial cells. Unlike the role reported for MgtC in other intracellular pathogens, Mma MgtC does not contribute significantly to intramacrophage replication. Taken together, these results indicate an unanticipated function of Mma MgtC at early step of infection within phagocytic cells. Hence, our results indicate that although the MgtC function is conserved among pathogens regarding adaptation to Mg2+ deprivation, its role towards phagocytic cells can differ, possibly in relation with the specific pathogen's lifestyles.
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Affiliation(s)
- Claudine Belon
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Universités Montpellier 2 et 1, Place Eugène Bataillon, 34095, Montpellier, Cedex 05, France
- Centre National de la Recherche Scientifique, UMR5235, Montpellier, France
| | - Laïla Gannoun-Zaki
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Universités Montpellier 2 et 1, Place Eugène Bataillon, 34095, Montpellier, Cedex 05, France
- Centre National de la Recherche Scientifique, UMR5235, Montpellier, France
| | - Georges Lutfalla
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Universités Montpellier 2 et 1, Place Eugène Bataillon, 34095, Montpellier, Cedex 05, France
- Centre National de la Recherche Scientifique, UMR5235, Montpellier, France
| | - Laurent Kremer
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Universités Montpellier 2 et 1, Place Eugène Bataillon, 34095, Montpellier, Cedex 05, France
- Centre National de la Recherche Scientifique, UMR5235, Montpellier, France
- Institut national de la santé et de la recherche médicale, Montpellier, France
| | - Anne-Béatrice Blanc-Potard
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Universités Montpellier 2 et 1, Place Eugène Bataillon, 34095, Montpellier, Cedex 05, France
- Centre National de la Recherche Scientifique, UMR5235, Montpellier, France
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CRP Acts as a Transcriptional Repressor of the YPO1635-phoPQ-YPO1632 Operon in Yersinia pestis. Curr Microbiol 2014; 70:398-403. [DOI: 10.1007/s00284-014-0736-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 10/16/2014] [Indexed: 11/25/2022]
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Heroven AK, Dersch P. Coregulation of host-adapted metabolism and virulence by pathogenic yersiniae. Front Cell Infect Microbiol 2014; 4:146. [PMID: 25368845 PMCID: PMC4202721 DOI: 10.3389/fcimb.2014.00146] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 09/30/2014] [Indexed: 01/07/2023] Open
Abstract
Deciphering the principles how pathogenic bacteria adapt their metabolism to a specific host microenvironment is critical for understanding bacterial pathogenesis. The enteric pathogenic Yersinia species Yersinia pseudotuberculosis and Yersinia enterocolitica and the causative agent of plague, Yersinia pestis, are able to survive in a large variety of environmental reservoirs (e.g., soil, plants, insects) as well as warm-blooded animals (e.g., rodents, pigs, humans) with a particular preference for lymphatic tissues. In order to manage rapidly changing environmental conditions and interbacterial competition, Yersinia senses the nutritional composition during the course of an infection by special molecular devices, integrates this information and adapts its metabolism accordingly. In addition, nutrient availability has an impact on expression of virulence genes in response to C-sources, demonstrating a tight link between the pathogenicity of yersiniae and utilization of nutrients. Recent studies revealed that global regulatory factors such as the cAMP receptor protein (Crp) and the carbon storage regulator (Csr) system are part of a large network of transcriptional and posttranscriptional control strategies adjusting metabolic changes and virulence in response to temperature, ion and nutrient availability. Gained knowledge about the specific metabolic requirements and the correlation between metabolic and virulence gene expression that enable efficient host colonization led to the identification of new potential antimicrobial targets.
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Affiliation(s)
- Ann Kathrin Heroven
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Institut für Mikrobiology, Technische Universität Braunschweig Braunschweig, Germany
| | - Petra Dersch
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Institut für Mikrobiology, Technische Universität Braunschweig Braunschweig, Germany
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Ford DC, Joshua GWP, Wren BW, Oyston PCF. The importance of the magnesium transporter MgtB for virulence of Yersinia pseudotuberculosis and Yersinia pestis. MICROBIOLOGY-SGM 2014; 160:2710-2717. [PMID: 25234474 DOI: 10.1099/mic.0.080556-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Mg(2+) has been shown to be an important signal controlling gene regulation via the PhoPQ two-component regulatory system for a range of Gram-negative bacteria, including Yersinia pestis and Yersinia pseudotuberculosis. The magnesium ion transporter MgtB is part of the complex PhoPQ regulon, being upregulated in response to low Mg(2+). Despite the presence of other Mg(2+) transport systems in Yersinia, inactivation of mgtB had a significant effect on the ability of the bacteria to scavenge this crucial ion. Whereas inactivation of PhoPQ is reported to adversely affect intracellular survival, we show that Y. pestis and Y. pseudotuberculosis ΔmgtB mutants survived equally as well as the respective parent strain within macrophages, although they were more sensitive to killing in the Galleria model of infection. Surprisingly, despite MgtB being only one member of the Mg(2+) stimulon and PhoPQ controlling the expression levels of a range of genes including mgtB, the Yersinia ΔmgtB mutants were more highly attenuated than the equivalent Yersinia ΔphoP mutants in mouse models of infection. MgtB may be a suitable target for development of novel antimicrobials, and investigation of its role may help elucidate the contribution of this component of the PhoPQ regulon to pathogenesis.
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Affiliation(s)
- Donna C Ford
- Biomedical Sciences, Dstl Porton Down, Salisbury SP4 0JQ, UK
| | - George W P Joshua
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Brendan W Wren
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
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Influence of PhoP and intra-species variations on virulence of Yersinia pseudotuberculosis during the natural oral infection route. PLoS One 2014; 9:e103541. [PMID: 25075520 PMCID: PMC4116203 DOI: 10.1371/journal.pone.0103541] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 07/03/2014] [Indexed: 01/02/2023] Open
Abstract
The two-component regulatory system PhoP/PhoQ has been shown to (i) control expression of virulence-associated traits, (ii) confer survival and growth within macrophages and (iii) play a role in Yersinia infections. However, the influence of PhoP on virulence varied greatly between different murine models of infection and its role in natural oral infections with frequently used representative isolates of Y. pseudotuberculosis was unknown. To address this issue, we constructed an isogenic set of phoP+ and phoP− variants of strain IP32953 and YPIII and analyzed the impact of PhoP using in vitro functionality experiments and a murine oral infection model, whereby we tested for bacterial dissemination and influence on the host immune response. Our results revealed that PhoP has a low impact on virulence, lymphatic and systemic organ colonization, and on immune response modulation by IP32953 and YPIII, indicating that PhoP is not absolutely essential for oral infections but may be involved in fine-tuning the outcome. Our work further revealed certain strain-specific differences in virulence properties, which do not strongly rely on the function of PhoP, but affect tissue colonization, dissemination and/or persistence of the bacteria. Highlighted intra-species variations may provide a potential means to rapidly adjust to environmental changes inside and outside of the host.
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Nuss AM, Schuster F, Kathrin Heroven A, Heine W, Pisano F, Dersch P. A direct link between the global regulator PhoP and the Csr regulon in Y. pseudotuberculosis through the small regulatory RNA CsrC. RNA Biol 2014; 11:580-93. [PMID: 24786463 DOI: 10.4161/rna.28676] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
In this study we investigated the influence of the global response regulator PhoP on the complex regulatory cascade controlling expression of early stage virulence genes of Yersinia pseudotuberculosis via the virulence regulator RovA. Our analysis revealed the following novel features: (1) PhoP activates expression of the CsrC RNA in Y. pseudotuberculosis, leading to activation of RovA synthesis through the CsrABC-RovM cascade, (2) activation of csrC transcription is direct and PhoP is shown to bind to two separate PhoP box-like sites, (3) PhoP-mediated activation results in transcription from two different promoters closely downstream of the PhoP binding sites, leading to two distinct CsrC RNAs, and (4) the stability of the CsrC RNAs differs significantly between the Y. pseudotuberculosis strains YPIII and IP32953 due to a 20 nucleotides insertion in CsrC(IP32953), which renders the transcript more susceptible to degradation. In summary, our study showed that PhoP-mediated influence on the regulatory cascade controlling the Csr system and RovA in Y. pseudotuberculosis varies within the species, suggesting that the Csr system is a focal point to readjust and adapt the genus to different hosts and reservoirs.
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Affiliation(s)
- Aaron M Nuss
- Department of Molecular Infection Biology; Helmholtz Centre for Infection Research; Braunschweig, Germany
| | - Franziska Schuster
- Department of Molecular Infection Biology; Helmholtz Centre for Infection Research; Braunschweig, Germany
| | - Ann Kathrin Heroven
- Department of Molecular Infection Biology; Helmholtz Centre for Infection Research; Braunschweig, Germany
| | - Wiebke Heine
- Department of Molecular Infection Biology; Helmholtz Centre for Infection Research; Braunschweig, Germany
| | - Fabio Pisano
- Department of Molecular Infection Biology; Helmholtz Centre for Infection Research; Braunschweig, Germany
| | - Petra Dersch
- Department of Molecular Infection Biology; Helmholtz Centre for Infection Research; Braunschweig, Germany
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Control of a Salmonella virulence operon by proline-charged tRNA(Pro). Proc Natl Acad Sci U S A 2014; 111:3140-5. [PMID: 24516160 DOI: 10.1073/pnas.1316209111] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The intracellular pathogen Salmonella enterica serovar Typhimurium requires the mgtC gene to cause disease. The mgtC transcript includes a long leader region that harbors a short proline codon-rich ORF--termed mgtP--the translation of which is predicted to favor formation of one of two alternative stem-loop structures. We now report that the mgtP proline codons are critical for expression of the mgtC coding region inside host cells, for Salmonella survival inside macrophages, and for virulence in mice. We determine that the mgtP proline codons mediate the response to proline-charged tRNA(Pro), the levels of which decrease under proline limitation and/or hyperosmotic stress. The host compartment harboring Salmonella appears to be limited in proline because proline auxotrophs were defective for intramacrophage survival and virulence in mice. Salmonella seems to experience hyperosmotic stress during infection because osmotically regulated genes were highly induced inside phagocytic cells. Replacing mgtP proline codons with codons specifying threonine converted the mgtC leader into a threonine-responding element. Our findings indicate that an attenuation-like mechanism governs transcription elongation into the mgtCBR coding region. Moreover, they highlight how pathogens construe host signals by the effect they have on bacterial constituents.
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Ke Y, Chen Z, Yang R. Yersinia pestis: mechanisms of entry into and resistance to the host cell. Front Cell Infect Microbiol 2013; 3:106. [PMID: 24400226 PMCID: PMC3871965 DOI: 10.3389/fcimb.2013.00106] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 12/10/2013] [Indexed: 12/28/2022] Open
Abstract
During infection, Yersinia, a facultative intracellular bacterial species, exhibits the ability to first invade host cells and then counteract phagocytosis by the host cells. During these two distinct stages, invasion or antiphagocytic factors assist bacteria in manipulating host cells to accomplish each of these functions; however, the mechanism through which Yersinia regulates these functions during each step remains unclear. Here, we discuss those factors that seem to function reversely and give some hypothesis about how bacteria switch between the two distinct status.
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Affiliation(s)
- Yuehua Ke
- Institute of Disease Control and Prevention, Academy of Military Medical Sciences Beijing, China ; Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences Beijing, China
| | - Zeliang Chen
- Institute of Disease Control and Prevention, Academy of Military Medical Sciences Beijing, China
| | - Ruifu Yang
- Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences Beijing, China
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