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Zhi F, Liu K, Geng H, Su M, Xu J, Fu L, Ma K, Gao P, Yuan L, Chu Y. Copper sensing transcription factor ArsR2 regulates VjbR to sustain virulence in Brucella abortus. Emerg Microbes Infect 2024; 13:2406274. [PMID: 39295505 PMCID: PMC11425708 DOI: 10.1080/22221751.2024.2406274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2024] [Revised: 09/10/2024] [Accepted: 09/16/2024] [Indexed: 09/21/2024]
Abstract
Brucellosis, caused by the intracellular pathogen Brucella, is a major zoonotic infection that promotes reproductive disease in domestic animals and chronic debilitating conditions in humans. The ArsR family of transcriptional regulators plays key roles in diverse cellular processes, including metal ion homeostasis, responding to adverse conditions, and virulence. However, little is known about the function of ArsR family members in Brucella. Here, we identified ArsR2 as a nonclassical member of the family that lacks autoregulatory function, but which nevertheless plays a vital role in maintaining copper homeostasis in B. abortus. ArsR2 is a global regulator of 241 genes, including those involved in the VirB type IV secretion system (T4SS). Significantly, ArsR2 regulates T4SS production in B. abortus by targeting VjbR which encodes a LuxR-type family transcriptional regulator. Moreover, copper modulates transcriptional activity of ArsR2, but not of VjbR. Furthermore, deletion of arsR2 attenuated virulence in a mouse model. Collectively, these findings enhance understanding of the mechanism by which ArsR proteins regulate virulence gene expression in pathogenic Brucella species.
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Affiliation(s)
- Feijie Zhi
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou Veterinary Research Institute, Lanzhou University, Chinese Academy of Agricultural Sciences, Lanzhou, People’s Republic of China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou, People’s Republic of China
- Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Ruminant Disease Prevention and Control (West), Ministry of Agricultural and Rural Affairs, Lanzhou, People’s Republic of China
| | - Kemeng Liu
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou Veterinary Research Institute, Lanzhou University, Chinese Academy of Agricultural Sciences, Lanzhou, People’s Republic of China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou, People’s Republic of China
- Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Ruminant Disease Prevention and Control (West), Ministry of Agricultural and Rural Affairs, Lanzhou, People’s Republic of China
| | - Hao Geng
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou Veterinary Research Institute, Lanzhou University, Chinese Academy of Agricultural Sciences, Lanzhou, People’s Republic of China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou, People’s Republic of China
- Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Ruminant Disease Prevention and Control (West), Ministry of Agricultural and Rural Affairs, Lanzhou, People’s Republic of China
| | - Mengru Su
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou Veterinary Research Institute, Lanzhou University, Chinese Academy of Agricultural Sciences, Lanzhou, People’s Republic of China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou, People’s Republic of China
- Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Ruminant Disease Prevention and Control (West), Ministry of Agricultural and Rural Affairs, Lanzhou, People’s Republic of China
| | - Jian Xu
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou Veterinary Research Institute, Lanzhou University, Chinese Academy of Agricultural Sciences, Lanzhou, People’s Republic of China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou, People’s Republic of China
- Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Ruminant Disease Prevention and Control (West), Ministry of Agricultural and Rural Affairs, Lanzhou, People’s Republic of China
| | - Lei Fu
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou Veterinary Research Institute, Lanzhou University, Chinese Academy of Agricultural Sciences, Lanzhou, People’s Republic of China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou, People’s Republic of China
- Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Ruminant Disease Prevention and Control (West), Ministry of Agricultural and Rural Affairs, Lanzhou, People’s Republic of China
| | - Ke Ma
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou Veterinary Research Institute, Lanzhou University, Chinese Academy of Agricultural Sciences, Lanzhou, People’s Republic of China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou, People’s Republic of China
- Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Ruminant Disease Prevention and Control (West), Ministry of Agricultural and Rural Affairs, Lanzhou, People’s Republic of China
| | - Pengcheng Gao
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou Veterinary Research Institute, Lanzhou University, Chinese Academy of Agricultural Sciences, Lanzhou, People’s Republic of China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou, People’s Republic of China
- Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Ruminant Disease Prevention and Control (West), Ministry of Agricultural and Rural Affairs, Lanzhou, People’s Republic of China
| | - Lvfeng Yuan
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou Veterinary Research Institute, Lanzhou University, Chinese Academy of Agricultural Sciences, Lanzhou, People’s Republic of China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou, People’s Republic of China
- Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Ruminant Disease Prevention and Control (West), Ministry of Agricultural and Rural Affairs, Lanzhou, People’s Republic of China
| | - YueFeng Chu
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou Veterinary Research Institute, Lanzhou University, Chinese Academy of Agricultural Sciences, Lanzhou, People’s Republic of China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou, People’s Republic of China
- Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Ruminant Disease Prevention and Control (West), Ministry of Agricultural and Rural Affairs, Lanzhou, People’s Republic of China
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Barton IS, Ren Z, Cribb CB, Pitzer JE, Baglivo I, Martin DW, Wang X, Roop RM. Brucella MucR acts as an H-NS-like protein to silence virulence genes and structure the nucleoid. mBio 2023; 14:e0220123. [PMID: 37847580 PMCID: PMC10746212 DOI: 10.1128/mbio.02201-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 08/21/2023] [Indexed: 10/19/2023] Open
Abstract
IMPORTANCE Histone-like nucleoid structuring (H-NS) and H-NS-like proteins coordinate host-associated behaviors in many pathogenic bacteria, often through forming silencer/counter-silencer pairs with signal-responsive transcriptional activators to tightly control gene expression. Brucella and related bacteria do not encode H-NS or homologs of known H-NS-like proteins, and it is unclear if they have other proteins that perform analogous functions during pathogenesis. In this work, we provide compelling evidence for the role of MucR as a novel H-NS-like protein in Brucella. We show that MucR possesses many of the known functions attributed to H-NS and H-NS-like proteins, including the formation of silencer/counter-silencer pairs to control virulence gene expression and global structuring of the nucleoid. These results uncover a new role for MucR as a nucleoid structuring protein and support the importance of temporal control of gene expression in Brucella and related bacteria.
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Affiliation(s)
- Ian S. Barton
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Zhongqing Ren
- Department of Biology, Indiana University, Bloomington, Indiana, USA
| | - Connor B. Cribb
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Joshua E. Pitzer
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Ilaria Baglivo
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, Caserta, Italy
| | - Daniel W. Martin
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Xindan Wang
- Department of Biology, Indiana University, Bloomington, Indiana, USA
| | - R. Martin Roop
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
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The regulon of Brucella abortus two-component system BvrR/BvrS reveals the coordination of metabolic pathways required for intracellular life. PLoS One 2022; 17:e0274397. [PMID: 36129877 PMCID: PMC9491525 DOI: 10.1371/journal.pone.0274397] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 08/26/2022] [Indexed: 11/19/2022] Open
Abstract
Brucella abortus is a facultative intracellular pathogen causing a severe zoonotic disease worldwide. The two-component regulatory system (TCS) BvrR/BvrS of B. abortus is conserved in members of the Alphaproteobacteria class. It is related to the expression of genes required for host interaction and intracellular survival. Here we report that bvrR and bvrS are part of an operon composed of 16 genes encoding functions related to nitrogen metabolism, DNA repair and recombination, cell cycle arrest, and stress response. Synteny of this genomic region within close Alphaproteobacteria members suggests a conserved role in coordinating the expression of carbon and nitrogen metabolic pathways. In addition, we performed a ChIP-Seq analysis after exposure of bacteria to conditions that mimic the intracellular environment. Genes encoding enzymes at metabolic crossroads of the pentose phosphate shunt, gluconeogenesis, cell envelope homeostasis, nucleotide synthesis, cell division, and virulence are BvrR/BvrS direct targets. A 14 bp DNA BvrR binding motif was found and investigated in selected gene targets such as virB1, bvrR, pckA, omp25, and tamA. Understanding gene expression regulation is essential to elucidate how Brucella orchestrates a physiological response leading to a furtive pathogenic strategy.
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Bacterial Transcriptional Regulators: A Road Map for Functional, Structural, and Biophysical Characterization. Int J Mol Sci 2022; 23:ijms23042179. [PMID: 35216300 PMCID: PMC8879271 DOI: 10.3390/ijms23042179] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 02/11/2022] [Accepted: 02/11/2022] [Indexed: 12/12/2022] Open
Abstract
The different niches through which bacteria move during their life cycle require a fast response to the many environmental queues they encounter. The sensing of these stimuli and their correct response is driven primarily by transcriptional regulators. This kind of protein is involved in sensing a wide array of chemical species, a process that ultimately leads to the regulation of gene transcription. The allosteric-coupling mechanism of sensing and regulation is a central aspect of biological systems and has become an important field of research during the last decades. In this review, we summarize the state-of-the-art techniques applied to unravel these complex mechanisms. We introduce a roadmap that may serve for experimental design, depending on the answers we seek and the initial information we have about the system of study. We also provide information on databases containing available structural information on each family of transcriptional regulators. Finally, we discuss the recent results of research about the allosteric mechanisms of sensing and regulation involving many transcriptional regulators of interest, highlighting multipronged strategies and novel experimental techniques. The aim of the experiments discussed here was to provide a better understanding at a molecular level of how bacteria adapt to the different environmental threats they face.
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Jaboulay C, Godeux AS, Doublet P, Vianney A. Regulatory Networks of the T4SS Control: From Host Cell Sensing to the Biogenesis and the Activity during the Infection. J Mol Biol 2021; 433:166892. [PMID: 33636165 DOI: 10.1016/j.jmb.2021.166892] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 02/17/2021] [Accepted: 02/17/2021] [Indexed: 02/03/2023]
Abstract
Delivery of effectors, DNA or proteins, that hijack host cell processes to the benefit of bacteria is a mechanism widely used by bacterial pathogens. It is achieved by complex effector injection devices, the secretion systems, among which Type 4 Secretion Systems (T4SSs) play a key role in bacterial virulence of numerous animal and plant pathogens. Considerable progress has recently been made in the structure-function analyses of T4SSs. Nevertheless, the signals and processes that trigger machine assembly and activity during infection, as well as those involved in substrate recognition and transfer, are complex and still poorly understood. In this review, we aim at summarizing the last updates of the knowledge on signaling pathways that regulate the biogenesis and the activity of T4SSs in important bacterial pathogens.
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Affiliation(s)
- C Jaboulay
- CIRI, Centre International de Recherche en Infectiologie, (Team: Legionella pathogenesis), Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, F-69007 Lyon, France.
| | - A S Godeux
- CIRI, Centre International de Recherche en Infectiologie, (Team: Horigene), Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, F-69007 Lyon, France
| | - P Doublet
- CIRI, Centre International de Recherche en Infectiologie, (Team: Legionella pathogenesis), Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, F-69007 Lyon, France
| | - A Vianney
- CIRI, Centre International de Recherche en Infectiologie, (Team: Legionella pathogenesis), Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, F-69007 Lyon, France
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Roop RM, Barton IS, Hopersberger D, Martin DW. Uncovering the Hidden Credentials of Brucella Virulence. Microbiol Mol Biol Rev 2021; 85:e00021-19. [PMID: 33568459 PMCID: PMC8549849 DOI: 10.1128/mmbr.00021-19] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Bacteria in the genus Brucella are important human and veterinary pathogens. The abortion and infertility they cause in food animals produce economic hardships in areas where the disease has not been controlled, and human brucellosis is one of the world's most common zoonoses. Brucella strains have also been isolated from wildlife, but we know much less about the pathobiology and epidemiology of these infections than we do about brucellosis in domestic animals. The brucellae maintain predominantly an intracellular lifestyle in their mammalian hosts, and their ability to subvert the host immune response and survive and replicate in macrophages and placental trophoblasts underlies their success as pathogens. We are just beginning to understand how these bacteria evolved from a progenitor alphaproteobacterium with an environmental niche and diverged to become highly host-adapted and host-specific pathogens. Two important virulence determinants played critical roles in this evolution: (i) a type IV secretion system that secretes effector molecules into the host cell cytoplasm that direct the intracellular trafficking of the brucellae and modulate host immune responses and (ii) a lipopolysaccharide moiety which poorly stimulates host inflammatory responses. This review highlights what we presently know about how these and other virulence determinants contribute to Brucella pathogenesis. Gaining a better understanding of how the brucellae produce disease will provide us with information that can be used to design better strategies for preventing brucellosis in animals and for preventing and treating this disease in humans.
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Affiliation(s)
- R Martin Roop
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Ian S Barton
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Dariel Hopersberger
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Daniel W Martin
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
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Brucella abortus Senses the Intracellular Environment through the BvrR/BvrS Two-Component System, Which Allows B. abortus To Adapt to Its Replicative Niche. Infect Immun 2018; 86:IAI.00713-17. [PMID: 29378792 DOI: 10.1128/iai.00713-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 01/16/2018] [Indexed: 02/06/2023] Open
Abstract
Brucella abortus is a facultative extracellular-intracellular pathogen belonging to a group of Alphaproteobacteria that establishes close interactions with animal cells. This bacterium enters host cells in a membrane-bound compartment, avoiding the lysosomal route and reaching the endoplasmic reticulum through the action of the type IV secretion system, VirB. In this work, we demonstrate that the BvrR/BvrS two-component system senses the intracellular environment to mount the transcriptional response required for intracellular life adaptation. By combining a method to purify intracellularly extracted bacteria with a strategy that allows direct determination of BvrR phosphorylation, we showed that upon entrance to host cells, the regulatory protein BvrR was activated (BvrR-P) by phosphorylation at aspartate 58. This activation takes place in response to intracellular cues found in early compartments, such as low pH and nutrient deprivation. Furthermore, BvrR activation was followed by an increase in the expression of VjbR and VirB. The in vitro activation of this BvrR-P/VjbR/VirB virulence circuit rescued B. abortus from the inhibition of intracellular replication induced by bafilomycin treatment of cells, demonstrating the relevance of this mechanism for intracellular bacterial survival and replication. All together, our results indicate that B. abortus senses the transition from the extracellular to the intracellular milieu through BvrR/BvrS, allowing the bacterium to transit safely to its replicative niche. These results serve as a working model for understanding the role of this family of two-component systems in the adaptation to intracellular life of Alphaproteobacteria.
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Sieira R, Bialer MG, Roset MS, Ruiz-Ranwez V, Langer T, Arocena GM, Mancini E, Zorreguieta A. Combinatorial control of adhesion of Brucella abortus 2308 to host cells by transcriptional rewiring of the trimeric autotransporter btaE gene. Mol Microbiol 2016; 103:553-565. [PMID: 27862467 DOI: 10.1111/mmi.13576] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/07/2016] [Indexed: 11/28/2022]
Abstract
Regulatory network plasticity is a key attribute underlying changes in bacterial gene expression and a source of phenotypic diversity to interact with the surrounding environment. Here, we sought to study the transcriptional circuit of HutC, a regulator of both metabolic and virulence genes of the facultative intracellular pathogen Brucella. Using in silico and biochemical approaches, we identified a novel functional HutC-binding site upstream of btaE, a trimeric-autotransporter adhesin involved in the attachment of Brucella to host extracellular matrix components. Moreover, we identified two additional regulators, one of which, MdrA, acts in concert with HutC to exert a combinatorial control of both btaE promoter activity and attachment of Brucella to HeLa cells. Analysis of btaE promoter sequences of different species indicated that this HutC-binding site was generated de novo by a single point mutation in a virulent Brucella strain, indicative of a transcriptional rewiring event. In addition to major domain organization differences existing between BtaE proteins within the genus Brucella, our analyses revealed that sequences upstream of btaE display high variability probably associated to intrinsic promoter structural features, which may serve as a substrate for reciprocal selection during co-evolution between this pathogen and its mammalian host.
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Affiliation(s)
- Rodrigo Sieira
- Fundación Instituto Leloir, Av. Patricias Argentinas 435, Buenos Aires, C1405BWE, Argentina
| | - Magalí G Bialer
- Fundación Instituto Leloir, Av. Patricias Argentinas 435, Buenos Aires, C1405BWE, Argentina
| | - Mara S Roset
- IIB-INTECH, CONICET-UNSAM, San Martín, 1650, Argentina
| | - Verónica Ruiz-Ranwez
- Fundación Instituto Leloir, Av. Patricias Argentinas 435, Buenos Aires, C1405BWE, Argentina
| | - Tomás Langer
- Fundación Instituto Leloir, Av. Patricias Argentinas 435, Buenos Aires, C1405BWE, Argentina
| | - Gastón M Arocena
- Fundación Instituto Leloir, Av. Patricias Argentinas 435, Buenos Aires, C1405BWE, Argentina
| | - Estefanía Mancini
- Fundación Instituto Leloir, Av. Patricias Argentinas 435, Buenos Aires, C1405BWE, Argentina
| | - Angeles Zorreguieta
- Fundación Instituto Leloir, Av. Patricias Argentinas 435, Buenos Aires, C1405BWE, Argentina
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9
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Liu Q, Liu X, Yan F, He Y, Wei J, Zhang Y, Liu L, Sun Y. Comparative transcriptome analysis of Brucella melitensis in an acidic environment: Identification of the two-component response regulator involved in the acid resistance and virulence of Brucella. Microb Pathog 2015; 91:92-8. [PMID: 26691825 DOI: 10.1016/j.micpath.2015.11.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 11/06/2015] [Accepted: 11/09/2015] [Indexed: 01/01/2023]
Abstract
Brucella melitensis, encounters a very stressful environment in phagosomes, especially low pH levels. So identifying the genes that contribute to the replication and survival within an acidic environment is critical in understanding the pathogenesis of the Brucella bacteria. In our research, comparative transcriptome with RNA-seq were used to analyze the changes of genes in normal-medium culture and in pH4.4-medium culture. The results reveal that 113 genes expressed with significant differences (|log2Ratio| ≥ 3); about 44% genes expressed as up-regulated. With GO term analysis, structural constituent of the ribosome, rRNA binding, structural molecule activity, and cation-transporting ATPase activity were significantly enriched (p-value ≤ 0.05). These genes distributed in 51 pathways, in which ribosome and photosynthesis pathways were significantly enriched. Six pathways (oxidative phosphorylation, iron-transporting, bacterial secretion system, transcriptional regulation, two-component system, and ABC transporters pathways) tightly related to the intracellular survival and virulence of Brucella were analyzed. A two-component response regulator gene in the transcriptional regulation pathway, identified through gene deletion and complementary technologies, played an important role in the resistance to the acid-resistance and virulence of Brucella.
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Affiliation(s)
- Qianhong Liu
- Jilin Agricultural Science and Technology University, Jilin 132101, China.
| | - Xingyu Liu
- Guangzhou Airport Entry-Exit Inspection and Quarantine Brueau of P.R.C, Guangzhou 510470, China
| | - Feng Yan
- Jilin Agricultural Science and Technology University, Jilin 132101, China
| | - Yuhua He
- Jilin Agricultural Science and Technology University, Jilin 132101, China
| | - Jie Wei
- Jilin Agricultural Science and Technology University, Jilin 132101, China
| | - Yuanyuan Zhang
- Jilin Agricultural Science and Technology University, Jilin 132101, China
| | - Lu Liu
- Jilin Agricultural Science and Technology University, Jilin 132101, China
| | - Youpeng Sun
- Jilin Agricultural Science and Technology University, Jilin 132101, China
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10
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Moumène A, Meyer DF. Ehrlichia's molecular tricks to manipulate their host cells. Microbes Infect 2015; 18:172-9. [PMID: 26617397 DOI: 10.1016/j.micinf.2015.11.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 10/09/2015] [Accepted: 11/04/2015] [Indexed: 01/27/2023]
Abstract
Ehrlichia is a large genus of obligate intracellular Gram-negative bacteria transmitted by ticks that cause several emerging infectious diseases in humans and are pathogenic on rodents, ruminants, and dogs. Ehrlichia spp. invade and replicate either in endothelial cells, white blood cells, or within midgut cells and salivary glands of their vector ticks. In this review, we discuss the insights that functional studies are providing on how this group of bacteria exploits their host by subverting host innate immunity and hijacking cellular processes.
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Affiliation(s)
- Amal Moumène
- CIRAD, UMR CMAEE, Site de Duclos, Prise d'eau, F-97170 Petit-Bourg, Guadeloupe, France; INRA, UMR1309 CMAEE, F-34398 Montpellier, France; Université des Antilles et de la Guyane, 97159 Pointe-à-Pitre Cedex, Guadeloupe, France
| | - Damien F Meyer
- CIRAD, UMR CMAEE, Site de Duclos, Prise d'eau, F-97170 Petit-Bourg, Guadeloupe, France; INRA, UMR1309 CMAEE, F-34398 Montpellier, France.
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11
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Ke Y, Wang Y, Li W, Chen Z. Type IV secretion system of Brucella spp. and its effectors. Front Cell Infect Microbiol 2015; 5:72. [PMID: 26528442 PMCID: PMC4602199 DOI: 10.3389/fcimb.2015.00072] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Accepted: 09/28/2015] [Indexed: 11/13/2022] Open
Abstract
Brucella spp. are intracellular bacterial pathogens that cause infection in domestic and wild animals. They are often used as model organisms to study intracellular bacterial infections. Brucella VirB T4SS is a key virulence factor that plays important roles in mediating intracellular survival and manipulating host immune response to infection. In this review, we discuss the roles of Brucella VirB T4SS and 15 effectors that are proposed to be crucial for Brucella pathogenesis. VirB T4SS regulates the inflammation response and manipulates vesicle trafficking inside host cells. VirB T4SS also plays crucial roles in the inhibition of the host immune response and intracellular survival during infection. Here, we list the key molecular events in the intracellular life cycle of Brucella that are potentially targeted by the VirB T4SS effectors. Elucidating the functions of these effectors will help clarify the molecular role of T4SS during infection. Furthermore, studying the effectors secreted by Brucella spp. might provide insights into the mechanisms used by the bacteria to hijack the host signaling pathways and aid in the development of better vaccines and therapies against brucellosis.
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Affiliation(s)
- Yuehua Ke
- Institute of Disease Control and Prevention, AMMS Beijing, China
| | - Yufei Wang
- Department of Laboratory Medicine, General Hospital of Chinese People's Armed Police Forces Beijing, China
| | - Wengfeng Li
- Department of Orthopedics, The First Affiliated Hospital of General Hospital of People's Liberation Army Beijing, China
| | - Zeliang Chen
- Institute of Disease Control and Prevention, AMMS Beijing, China
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12
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Döhmer PH, Valguarnera E, Czibener C, Ugalde JE. Identification of a type IV secretion substrate of Brucella abortus that participates in the early stages of intracellular survival. Cell Microbiol 2014; 16:396-410. [PMID: 24119283 PMCID: PMC3945426 DOI: 10.1111/cmi.12224] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 09/03/2013] [Accepted: 10/05/2013] [Indexed: 01/19/2023]
Abstract
Brucella abortus, the aetiological agent of bovine brucellosis, is an intracellular pathogen whose virulence is completely dependent on a type IV secretion system. This secretion system translocates effector proteins into the host cell to modulate the intracellular fate of the bacterium in order to establish a secure niche were it actively replicates. Although much has been done in understanding how this secretion system participates in the virulence process, few effector proteins have been identified to date. We describe here the identification of a type IV secretion substrate (SepA) that is only present in Brucella spp. and has no detectable homology to known proteins. This protein is secreted in a virB-dependent manner in a two-step process involving a periplasmic intermediate and secretion is necessary for its function. The deletion mutant showed a defect in the early stages of intracellular replication in professional and non-professional phagocytes although it invades the cells more efficiently than the wild-type parental strain. Our results indicate that, even though the mutant was more invasive, it had a defect in excluding the lysosomal marker Lamp-1 and was inactivated more efficiently during the early phases of the intracellular life cycle.
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Affiliation(s)
- Peter H. Döhmer
- Instituto de Investigaciones Biotecnológicas “Dr. Rodolfo A. Ugalde”, Instituto Tecnológico de Chascomús, IIB-INTECH, CONICET, Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | | | - Cecilia Czibener
- Instituto de Investigaciones Biotecnológicas “Dr. Rodolfo A. Ugalde”, Instituto Tecnológico de Chascomús, IIB-INTECH, CONICET, Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | - Juan E. Ugalde
- Instituto de Investigaciones Biotecnológicas “Dr. Rodolfo A. Ugalde”, Instituto Tecnológico de Chascomús, IIB-INTECH, CONICET, Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
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Sieira R. Regulation of virulence in Brucella: an eclectic repertoire of transcription factors defines the complex architecture of the virB promoter. Future Microbiol 2013; 8:1193-208. [DOI: 10.2217/fmb.13.83] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Many intracellular bacterial pathogens use type IV secretion systems to deliver effector molecules and subvert the eukaryotic host cell defenses. The genus Brucella comprises facultative intracellular bacteria that cause brucellosis, a disease affecting a wide range of mammals including humans. The virB operon codes for a type IV secretion system that plays a central role in intracellular survival and replication of Brucella within the host. Expression of the virB genes is under the control of various transcription factors that allow this system to respond to different types of environmental signals, and display binding site structures and arrangements that define the intrinsic complexity of the virB promoter. This review focuses on summarizing the current state of research concerning regulation of the Brucella virB operon, with special emphasis on describing the nature and function of the implicated regulatory elements and examining the involved protein–DNA interactions.
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Affiliation(s)
- Rodrigo Sieira
- Fundación Instituto Leloir-IIBBA-CONICET, Av. Patricias Argentinas 435, Buenos Aires C1405BWE, Argentina
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