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Chaves-Olarte E, Meza-Torres J, Herrera-Rodríguez F, Lizano-González E, Suárez-Esquivel M, Baker KS, Rivas-Solano O, Ruiz-Villalobos N, Villalta-Romero F, Cheng HP, Walker GC, Cloeckaert A, Thomson NR, Frisan T, Moreno E, Guzmán-Verri C. A sensor histidine kinase from a plant-endosymbiont bacterium restores the virulence of a mammalian intracellular pathogen. Microb Pathog 2023; 185:106442. [PMID: 37944675 PMCID: PMC10740080 DOI: 10.1016/j.micpath.2023.106442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 07/22/2023] [Accepted: 11/03/2023] [Indexed: 11/12/2023]
Abstract
Alphaproteobacteria include organisms living in close association with plants or animals. This interaction relies partly on orthologous two-component regulatory systems (TCS), with sensor and regulator proteins modulating the expression of conserved genes related to symbiosis/virulence. We assessed the ability of the exoS+Sm gene, encoding a sensor protein from the plant endosymbiont Sinorhizobium meliloti to substitute its orthologous bvrS in the related animal/human pathogen Brucella abortus. ExoS phosphorylated the B. abortus regulator BvrR in vitro and in cultured bacteria, showing conserved biological function. Production of ExoS in a B. abortus bvrS mutant reestablished replication in host cells and the capacity to infect mice. Bacterial outer membrane properties, the production of the type IV secretion system VirB, and its transcriptional regulators VjbR and BvrR were restored as compared to parental B. abortus. These results indicate that conserved traits of orthologous TCS from bacteria living in and sensing different environments are sufficient to achieve phenotypic plasticity and support bacterial survival. The knowledge of bacterial genetic networks regulating host interactions allows for an understanding of the subtle differences between symbiosis and parasitism. Rewiring these networks could provide new alternatives to control and prevent bacterial infection.
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Affiliation(s)
- Esteban Chaves-Olarte
- Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica; Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
| | - Jazmín Meza-Torres
- Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Fabiola Herrera-Rodríguez
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
| | - Esteban Lizano-González
- Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica; Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
| | - Marcela Suárez-Esquivel
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
| | - Kate S Baker
- Parasites and Microbes from Pathogen Genomics, Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, UK
| | - Olga Rivas-Solano
- Centro de Investigación en Biotecnología, Escuela de Biología, Instituto Tecnológico de Costa Rica, Cartago, Costa Rica
| | - Nazareth Ruiz-Villalobos
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
| | - Fabián Villalta-Romero
- Centro de Investigación en Biotecnología, Escuela de Biología, Instituto Tecnológico de Costa Rica, Cartago, Costa Rica
| | - Hai-Ping Cheng
- Biological Sciences Department, Lehman College, The City University of New York, New York, USA
| | - Graham C Walker
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - Nicholas R Thomson
- Parasites and Microbes from Pathogen Genomics, Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, UK
| | - Teresa Frisan
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Edgardo Moreno
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
| | - Caterina Guzmán-Verri
- Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica; Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica.
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2
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Chen X, Alakavuklar MA, Fiebig A, Crosson S. Cross-regulation in a three-component cell envelope stress signaling system of Brucella. mBio 2023; 14:e0238723. [PMID: 38032291 PMCID: PMC10746171 DOI: 10.1128/mbio.02387-23] [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: 09/06/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
IMPORTANCE As intracellular pathogens, Brucella must contend with a variety of host-derived stressors when infecting a host cell. The inner membrane, cell wall, and outer membrane, i.e. the cell envelope, of Brucella provide a critical barrier to host assault. A conserved regulatory mechanism known as two-component signaling (TCS) commonly controls transcription of genes that determine the structure and biochemical composition of the cell envelope during stress. We report the identification of previously uncharacterized TCS genes that determine Brucella ovis fitness in the presence of cell envelope disruptors and within infected mammalian host cells. Our study reveals a new molecular mechanism of TCS-dependent gene regulation, and thereby advances fundamental understanding of transcriptional regulatory processes in bacteria.
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Affiliation(s)
- Xingru Chen
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Melene A. Alakavuklar
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Aretha Fiebig
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Sean Crosson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
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3
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Wiesmann CL, Wang NR, Zhang Y, Liu Z, Haney CH. Origins of symbiosis: shared mechanisms underlying microbial pathogenesis, commensalism and mutualism of plants and animals. FEMS Microbiol Rev 2023; 47:fuac048. [PMID: 36521845 PMCID: PMC10719066 DOI: 10.1093/femsre/fuac048] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 12/07/2022] [Accepted: 12/09/2022] [Indexed: 12/17/2023] Open
Abstract
Regardless of the outcome of symbiosis, whether it is pathogenic, mutualistic or commensal, bacteria must first colonize their hosts. Intriguingly, closely related bacteria that colonize diverse hosts with diverse outcomes of symbiosis have conserved host-association and virulence factors. This review describes commonalities in the process of becoming host associated amongst bacteria with diverse lifestyles. Whether a pathogen, commensal or mutualist, bacteria must sense the presence of and migrate towards a host, compete for space and nutrients with other microbes, evade the host immune system, and change their physiology to enable long-term host association. We primarily focus on well-studied taxa, such as Pseudomonas, that associate with diverse model plant and animal hosts, with far-ranging symbiotic outcomes. Given the importance of opportunistic pathogens and chronic infections in both human health and agriculture, understanding the mechanisms that facilitate symbiotic relationships between bacteria and their hosts will help inform the development of disease treatments for both humans, and the plants we eat.
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Affiliation(s)
- Christina L Wiesmann
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Nicole R Wang
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Yue Zhang
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Zhexian Liu
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Cara H Haney
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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4
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Murugan S, Nandi BR, Mazumdar V, Joshi K, Nandini P, Namani S, Jakka P, Radhakrishnan GK. Outer membrane protein 25 of Brucella suppresses TLR-mediated expression of proinflammatory cytokines through degradation of TLRs and adaptor proteins. J Biol Chem 2023; 299:105309. [PMID: 37778729 PMCID: PMC10641269 DOI: 10.1016/j.jbc.2023.105309] [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: 02/08/2023] [Revised: 08/30/2023] [Accepted: 09/21/2023] [Indexed: 10/03/2023] Open
Abstract
Toll-like receptors (TLRs) are essential components of innate immunity that serves as the first line of defense against the invaded microorganisms. However, successful infectious pathogens subvert TLR signaling to suppress the activation of innate and adaptive responses. Brucella species are infectious intracellular bacterial pathogens causing the worldwide zoonotic disease, brucellosis, that impacts economic growth of many countries. Brucella species are considered as stealthy bacterial pathogens as they efficiently evade or suppress host innate and adaptive immune responses for their chronic persistence. However, the bacterial effectors and their host targets for modulating the immune responses remain obscure. Brucella encodes various outer membrane proteins (Omps) that facilitate their invasion, intracellular replication, and immunomodulation. Outer membrane protein 25 (Omp25) of Brucella plays an important role in the immune modulation through suppression of proinflammatory cytokines. However, the mechanism and the signaling pathways that are targeted by Omp25 to attenuate the production of proinflammatory cytokines remain obscure. Here, we report that Omp25 and its variants, viz. Omp25b, Omp25c, and Omp25d, suppress production of proinflammatory cytokines that are mediated by various TLRs. Furthermore, we demonstrate that Omp25 and its variants promote enhanced ubiquitination and degradation of TLRs and their adaptor proteins to attenuate the expression of proinflammatory cytokines. Targeting multiple TLRs and adaptor proteins enables Omp25 to effectively suppress the expression of proinflammatory cytokines that are induced by diverse pathogen-associated molecular patterns. This can contribute to the defective adaptive immune response and the chronic persistence of Brucella in the host.
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Affiliation(s)
- Subathra Murugan
- Laboratory of Immunology and Microbial Pathogenesis, National Institute of Animal Biotechnology, Hyderabad, Telangana, India; Centre for Biotechnology, Institute of Science and Technology, Jawaharlal Nehru Technological University, Hyderabad, India
| | - Binita Roy Nandi
- Laboratory of Immunology and Microbial Pathogenesis, National Institute of Animal Biotechnology, Hyderabad, Telangana, India; Regional Centre for Biotechnology (RCB), Faridabad, India
| | - Varadendra Mazumdar
- Laboratory of Immunology and Microbial Pathogenesis, National Institute of Animal Biotechnology, Hyderabad, Telangana, India; Regional Centre for Biotechnology (RCB), Faridabad, India
| | - Kiranmai Joshi
- Laboratory of Immunology and Microbial Pathogenesis, National Institute of Animal Biotechnology, Hyderabad, Telangana, India; Regional Centre for Biotechnology (RCB), Faridabad, India
| | - Prachita Nandini
- Laboratory of Immunology and Microbial Pathogenesis, National Institute of Animal Biotechnology, Hyderabad, Telangana, India; Regional Centre for Biotechnology (RCB), Faridabad, India
| | - Swapna Namani
- Laboratory of Immunology and Microbial Pathogenesis, National Institute of Animal Biotechnology, Hyderabad, Telangana, India
| | - Padmaja Jakka
- Laboratory of Immunology and Microbial Pathogenesis, National Institute of Animal Biotechnology, Hyderabad, Telangana, India
| | - Girish K Radhakrishnan
- Laboratory of Immunology and Microbial Pathogenesis, National Institute of Animal Biotechnology, Hyderabad, Telangana, India.
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5
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Chen X, Alakavuklar MA, Fiebig A, Crosson S. Cross regulation in a three-component cell envelope stress signaling system of Brucella. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.15.536747. [PMID: 37873345 PMCID: PMC10592609 DOI: 10.1101/2023.04.15.536747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
A multi-layered structure known as the cell envelope separates the controlled interior of bacterial cells from a fluctuating physical and chemical environment. The transcription of genes that determine cell envelope structure and function is commonly regulated by two-component signaling systems (TCS), comprising a sensor histidine kinase and a cognate response regulator. To identify TCS genes that contribute to cell envelope function in the intracellular mammalian pathogen, Brucella ovis, we subjected a collection of non-essential TCS deletion mutants to compounds that disrupt cell membranes and the peptidoglycan cell wall. Our screen led to the discovery of three TCS proteins that coordinately function to confer resistance to cell envelope stressors and to support B. ovis replication in the intracellular niche. This tripartite regulatory system includes the known cell envelope regulator, CenR, and a previously uncharacterized TCS, EssR-EssS, which is widely conserved in Alphaproteobacteria. The CenR and EssR response regulators bind a shared set of sites on the B. ovis chromosomes to control transcription of an overlapping set of genes with cell envelope functions. CenR directly interacts with EssR and functions to stimulate phosphoryl transfer from the EssS kinase to EssR, while CenR and EssR control the cellular levels of each other via a post-transcriptional mechanism. Our data provide evidence for a new mode of TCS cross-regulation in which a non-cognate response regulator affects both the activity and protein levels of a cognate TCS protein pair.
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Affiliation(s)
- Xingru Chen
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan USA
| | - Melene A Alakavuklar
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan USA
| | - Aretha Fiebig
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan USA
| | - Sean Crosson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan USA
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6
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Greenwich JL, Heckel BC, Alakavuklar MA, Fuqua C. The ChvG-ChvI Regulatory Network: A Conserved Global Regulatory Circuit Among the Alphaproteobacteria with Pervasive Impacts on Host Interactions and Diverse Cellular Processes. Annu Rev Microbiol 2023; 77:131-148. [PMID: 37040790 DOI: 10.1146/annurev-micro-120822-102714] [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] [Indexed: 04/13/2023]
Abstract
The ChvG-ChvI two-component system is conserved among multiple Alphaproteobacteria. ChvG is a canonical two-component system sensor kinase with a single large periplasmic loop. Active ChvG directs phosphotransfer to its cognate response regulator ChvI, which controls transcription of target genes. In many alphaproteobacteria, ChvG is regulated by a third component, a periplasmic protein called ExoR, that maintains ChvG in an inactive state through direct interaction. Acidic pH stimulates proteolysis of ExoR, unfettering ChvG-ChvI to control its regulatory targets. Activated ChvI among different alphaproteobacteria controls a broad range of cellular processes, including symbiosis and virulence, exopolysaccharide production, biofilm formation, motility, type VI secretion, cellular metabolism, envelope composition, and growth. Low pH is a virulence signal in Agrobacterium tumefaciens, but in other systems, conditions that cause envelope stress may also generally activate ChvG-ChvI. There is mounting evidence that these regulators influence diverse aspects of bacterial physiology, including but not limited to host interactions.
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Affiliation(s)
| | - Brynn C Heckel
- Department of Biology, Indiana University, Bloomington, Indiana, USA; ,
- Current affiliation: California State University, Dominguez Hills, California, USA;
| | - Melene A Alakavuklar
- Department of Biology, Indiana University, Bloomington, Indiana, USA; ,
- Current affiliation: Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA;
| | - Clay Fuqua
- Department of Biology, Indiana University, Bloomington, Indiana, USA; ,
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7
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Alakavuklar MA, Fiebig A, Crosson S. The Brucella Cell Envelope. Annu Rev Microbiol 2023; 77:233-253. [PMID: 37104660 PMCID: PMC10787603 DOI: 10.1146/annurev-micro-032521-013159] [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] [Indexed: 04/29/2023]
Abstract
The cell envelope is a multilayered structure that insulates the interior of bacterial cells from an often chaotic outside world. Common features define the envelope across the bacterial kingdom, but the molecular mechanisms by which cells build and regulate this critical barrier are diverse and reflect the evolutionary histories of bacterial lineages. Intracellular pathogens of the genus Brucella exhibit marked differences in cell envelope structure, regulation, and biogenesis when compared to more commonly studied gram-negative bacteria and therefore provide an excellent comparative model for study of the gram-negative envelope. We review distinct features of the Brucella envelope, highlighting a conserved regulatory system that links cell cycle progression to envelope biogenesis and cell division. We further discuss recently discovered structural features of the Brucella envelope that ensure envelope integrity and that facilitate cell survival in the face of host immune stressors.
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Affiliation(s)
- Melene A Alakavuklar
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA;
| | - Aretha Fiebig
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA;
| | - Sean Crosson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA;
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8
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Castillo-Zeledón A, Rivas-Solano O, Villalta-Romero F, Gómez-Espinoza O, Moreno E, Chaves-Olarte E, Guzmán-Verri C. The Brucella abortus two-component system response regulator BvrR binds to three DNA regulatory boxes in the upstream region of omp25. Front Microbiol 2023; 14:1241143. [PMID: 37779712 PMCID: PMC10538546 DOI: 10.3389/fmicb.2023.1241143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 08/15/2023] [Indexed: 10/03/2023] Open
Abstract
Brucella abortus is a facultative extracellular-intracellular bacterial zoonotic pathogen worldwide. It is also a major cause of abortion in bovines, generating economic losses. The two-component regulatory system BvrR/BvrS modulates the expression of genes required to transition from extracellular to intracellular lifestyles. However, few regulatory regions of BvrR direct target genes have been studied. In this study, we characterized the regulatory region of omp25, a gene encoding an outer membrane protein that is positively regulated by TCS BvrR/BvrS. By omp25-lacZ reporter fusions and β-galactosidase activity assays, we found that the region between-262 and + 127 is necessary for transcriptional activity, particularly a 111-bp long fragment located from-262 to -152. In addition, we demonstrated the binding of P-BvrR to three sites within the -140 to +1 region. Two of these sites were delimited between -18 to +1 and - 99 to -76 by DNase I footprinting and called DNA regulatory boxes 1 and 2, respectively. The third binding site (box 3) was delimited from -140 to -122 by combining EMSA and fluorescence anisotropy results. A molecular docking analysis with HDOCK predicted BvrR-DNA interactions between 11, 13, and 12 amino acid residue-nucleotide pairs in boxes 1, 2, and 3, respectively. A manual sequence alignment of the three regulatory boxes revealed the presence of inverted and non-inverted repeats of five to eight nucleotides, partially matching DNA binding motifs previously described for BvrR. We propose that P-BvrR binds directly to up to three regulatory boxes and probably interacts with other transcription factors to regulate omp25 expression. This gene regulation model could apply to other BvrR target genes and to orthologs of the TCS BvrR/BvrS and Omp25 in phylogenetically closed Rhizobiales.
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Affiliation(s)
- Amanda Castillo-Zeledón
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional de Costa Rica, Heredia, Costa Rica
| | - Olga Rivas-Solano
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional de Costa Rica, Heredia, Costa Rica
- Centro de Investigación en Biotecnología, Escuela de Biología, Instituto Tecnológico de Costa Rica, Campus Tecnológico Central Cartago, Cartago, Costa Rica
| | - Fabián Villalta-Romero
- Centro de Investigación en Biotecnología, Escuela de Biología, Instituto Tecnológico de Costa Rica, Campus Tecnológico Central Cartago, Cartago, Costa Rica
| | - Olman Gómez-Espinoza
- Centro de Investigación en Biotecnología, Escuela de Biología, Instituto Tecnológico de Costa Rica, Campus Tecnológico Central Cartago, Cartago, Costa Rica
| | - Edgardo Moreno
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional de Costa Rica, Heredia, Costa Rica
| | - Esteban Chaves-Olarte
- Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Caterina Guzmán-Verri
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional de Costa Rica, Heredia, Costa Rica
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9
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Rivas-Solano O, Núñez-Montero K, Altamirano-Silva P, Ruiz-Villalobos N, Barquero-Calvo E, Moreno E, Chaves-Olarte E, Guzmán-Verri C. A bvrR/bvrS Non-Polar Brucella abortus Mutant Confirms the Role of the Two-Component System BvrR/BvrS in Virulence and Membrane Integrity. Microorganisms 2023; 11:2014. [PMID: 37630574 PMCID: PMC10459465 DOI: 10.3390/microorganisms11082014] [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: 06/28/2023] [Revised: 07/25/2023] [Accepted: 08/02/2023] [Indexed: 08/27/2023] Open
Abstract
Brucella abortus is a bacterial pathogen causing bovine brucellosis worldwide. This facultative extracellular-intracellular pathogen can be transmitted to humans, leading to a zoonotic disease. The disease remains a public health concern, particularly in regions where livestock farming is present. The two-component regulatory system BvrR/BvrS was described by isolating the attenuated transposition mutants bvrR::Tn5 and bvrS::Tn5, whose characterization led to the understanding of the role of the system in bacterial survival. However, a phenotypic comparison with deletion mutants has not been performed because their construction has been unsuccessful in brucellae and difficult in phylogenetically related Rhizobiales with BvrR/BvrS orthologs. Here, we used an unmarked gene excision strategy to generate a B. abortus mutant strain lacking both genes, called B. abortus ∆bvrRS. The deletion was verified through PCR, Southern blot, Western blot, Sanger sequencing, and whole-genome sequencing, confirming a clean mutation without further alterations at the genome level. B. abortus ∆bvrRS shared attenuated phenotypic traits with both transposition mutants, confirming the role of BvrR/BvrS in pathogenesis and membrane integrity. This B. abortus ∆bvrRS with a non-antimicrobial marker is an excellent tool for continuing studies on the role of BvrR/BvrS in the B. abortus lifestyle.
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Affiliation(s)
- Olga Rivas-Solano
- Centro de Investigación en Biotecnología, Instituto Tecnológico de Costa Rica, Cartago 30109, Costa Rica
| | - Kattia Núñez-Montero
- Laboratorio Facultad Ciencias de la Salud, Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Temuco 4813003, Chile;
| | - Pamela Altamirano-Silva
- Centro de Investigación en Enfermedades Tropicales, Universidad de Costa Rica, San Pedro de Montes de Oca, San José 2060, Costa Rica; (P.A.-S.); (E.C.-O.)
| | - Nazareth Ruiz-Villalobos
- Programa de Investigación en Enfermedades Tropicales, Universidad Nacional, Heredia 40104, Costa Rica; (N.R.-V.); (E.B.-C.); (E.M.); (C.G.-V.)
| | - Elías Barquero-Calvo
- Programa de Investigación en Enfermedades Tropicales, Universidad Nacional, Heredia 40104, Costa Rica; (N.R.-V.); (E.B.-C.); (E.M.); (C.G.-V.)
| | - Edgardo Moreno
- Programa de Investigación en Enfermedades Tropicales, Universidad Nacional, Heredia 40104, Costa Rica; (N.R.-V.); (E.B.-C.); (E.M.); (C.G.-V.)
| | - Esteban Chaves-Olarte
- Centro de Investigación en Enfermedades Tropicales, Universidad de Costa Rica, San Pedro de Montes de Oca, San José 2060, Costa Rica; (P.A.-S.); (E.C.-O.)
| | - Caterina Guzmán-Verri
- Programa de Investigación en Enfermedades Tropicales, Universidad Nacional, Heredia 40104, Costa Rica; (N.R.-V.); (E.B.-C.); (E.M.); (C.G.-V.)
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10
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Altamirano-Silva P, Meza-Torres J, Zúñiga-Pereira AM, Zamora-Jaen S, Pietrosemoli N, Cantos G, Peltier J, Pizarro-Cerdá J, Moreno E, Chacón-Díaz C, Guzmán-Verri C, Chaves-Olarte E. Phenotypes controlled by the Brucella abortus two component system BvrR/BvrS are differentially impacted by BvrR phosphorylation. Front Microbiol 2023; 14:1148233. [PMID: 37234533 PMCID: PMC10206243 DOI: 10.3389/fmicb.2023.1148233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 04/14/2023] [Indexed: 05/28/2023] Open
Abstract
Brucella abortus is a zoonotic pathogen whose virulence depends on its ability to survive intracellularly at the endoplasmic reticulum derived compartment. The two-component system BvrR/BvrS (BvrRS) is essential for intracellular survival due to the transcriptional control of the type IV secretion system VirB and its transcriptional regulator VjbR. It is a master regulator of several traits including membrane homeostasis by controlling gene expression of membrane components, such as Omp25. BvrR phosphorylation is related to DNA binding at target regions, thereby repressing or activating gene transcription. To understand the role of BvrR phosphorylation we generated dominant positive and negative versions of this response regulator, mimicking phosphorylated and non-phosphorylated BvrR states and, in addition to the wild-type version, these variants were introduced in a BvrR negative background. We then characterized BvrRS-controlled phenotypes and assessed the expression of proteins regulated by the system. We found two regulatory patterns exerted by BvrR. The first pattern was represented by resistance to polymyxin and expression of Omp25 (membrane conformation) which were restored to normal levels by the dominant positive and the wild-type version, but not the dominant negative BvrR. The second pattern was represented by intracellular survival and expression of VjbR and VirB (virulence) which were, again, complemented by the wild-type and the dominant positive variants of BvrR but were also significantly restored by complementation with the dominant negative BvrR. These results indicate a differential transcriptional response of the genes controlled to the phosphorylation status of BvrR and suggest that unphosphorylated BvrR binds and impacts the expression of a subset of genes. We confirmed this hypothesis by showing that the dominant negative BvrR did not interact with the omp25 promoter whereas it could interact with vjbR promoter. Furthermore, a global transcriptional analysis revealed that a subset of genes responds to the presence of the dominant negative BvrR. Thus, BvrR possesses diverse strategies to exert transcriptional control on the genes it regulates and, consequently, impacting on the phenotypes controlled by this response regulator.
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Affiliation(s)
- Pamela Altamirano-Silva
- Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Jazmín Meza-Torres
- Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Ana Mariel Zúñiga-Pereira
- Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Sigrid Zamora-Jaen
- Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Natalia Pietrosemoli
- Bioinformatics and Biostatistics Hub, CNRS USR3756, Institut Pasteur, Université Paris Cité, Paris, France
| | - Gabriela Cantos
- Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Johann Peltier
- Laboratoire Pathogenèse des Bactéries Anaérobies, CNRS UMR6047, Institut Pasteur, Université Paris Cité, Paris, France
- CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, Gif-sur-Yvette, France
| | - Javier Pizarro-Cerdá
- Yersinia Research Unit, CNRS UMR6047, Institut Pasteur, Université Paris Cité, Paris, France
| | - Edgardo Moreno
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
| | - Carlos Chacón-Díaz
- Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Caterina Guzmán-Verri
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
| | - Esteban Chaves-Olarte
- Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
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11
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Wiesmann CL, Zhang Y, Alford M, Hamilton CD, Dosanjh M, Thoms D, Dostert M, Wilson A, Pletzer D, Hancock REW, Haney CH. The ColR/S two-component system is a conserved determinant of host association across Pseudomonas species. THE ISME JOURNAL 2023; 17:286-296. [PMID: 36424517 PMCID: PMC9859794 DOI: 10.1038/s41396-022-01343-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 11/07/2022] [Accepted: 11/09/2022] [Indexed: 11/27/2022]
Abstract
Members of the bacterial genus Pseudomonas form mutualistic, commensal, and pathogenic associations with diverse hosts. The prevalence of host association across the genus suggests that symbiosis may be a conserved ancestral trait and that distinct symbiotic lifestyles may be more recently evolved. Here we show that the ColR/S two-component system, part of the Pseudomonas core genome, is functionally conserved between Pseudomonas aeruginosa and Pseudomonas fluorescens. Using plant rhizosphere colonization and virulence in a murine abscess model, we show that colR is required for commensalism with plants and virulence in animals. Comparative transcriptomics revealed that the ColR regulon has diverged between P. aeruginosa and P. fluorescens and deleting components of the ColR regulon revealed strain-specific, but not host-specific, requirements for ColR-dependent genes. Collectively, our results suggest that ColR/S allows Pseudomonas to sense and respond to a host, but that the ColR-regulon has diverged between Pseudomonas strains with distinct lifestyles. This suggests that conservation of two-component systems, coupled with life-style dependent diversification of the regulon, may play a role in host association and lifestyle transitions.
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Affiliation(s)
- Christina L Wiesmann
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Yue Zhang
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Morgan Alford
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
- 2259 Lower Mall Research Station, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Corri D Hamilton
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Manisha Dosanjh
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - David Thoms
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Melanie Dostert
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
- 2259 Lower Mall Research Station, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Andrew Wilson
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Daniel Pletzer
- 2259 Lower Mall Research Station, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Microbiology and Immunology, University of Otago, 720 Cumberland St., 9054, Dunedin, New Zealand
| | - Robert E W Hancock
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
- 2259 Lower Mall Research Station, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Cara H Haney
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
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12
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Orsini M, Ianni A, Zinzula L. Brucella ceti and Brucella pinnipedialis genome characterization unveils genetic features that highlight their zoonotic potential. Microbiologyopen 2022; 11:e1329. [PMID: 36314752 PMCID: PMC9597259 DOI: 10.1002/mbo3.1329] [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: 05/13/2022] [Revised: 10/07/2022] [Accepted: 10/07/2022] [Indexed: 11/06/2022] Open
Abstract
The Gram-negative bacteria Brucella ceti and Brucella pinnipedialis circulate in marine environments primarily infecting marine mammals, where they cause an often-fatal disease named brucellosis. The increase of brucellosis among several species of cetaceans and pinnipeds, together with the report of sporadic human infections, raises concerns about the zoonotic potential of these pathogens on a large scale and may pose a threat to coastal communities worldwide. Therefore, the characterization of the B. ceti and B. pinnipedialis genetic features is a priority to better understand the pathological factors that may impact global health. Moreover, an in-depth functional analysis of the B. ceti and B. pinnipedialis genome in the context of virulence and pathogenesis was not undertaken so far. Within this picture, here we present the comparative whole-genome characterization of all B. ceti and B. pinnipedialis genomes available in public resources, uncovering a collection of genetic tools possessed by these aquatic bacterial species compared to their zoonotic terrestrial relatives. We show that B. ceti and B. pinnipedialis genomes display a wide host-range infection capability and a polyphyletic phylogeny within the genus, showing a genomic structure that fits the canonical definition of closeness. Functional genome annotation led to identifying genes related to several pathways involved in mechanisms of infection, others conferring pan-susceptibility to antimicrobials and a set of virulence genes that highlight the similarity of B. ceti and B. pinnipedialis genotypes to those of Brucella spp. displaying human-infecting phenotypes.
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Affiliation(s)
- Massimiliano Orsini
- Istituto Zooprofilattico Sperimentale delle Venezie, Laboratory of Microbial Ecology and GenomicsLegnaroItaly
| | - Andrea Ianni
- Research Unit in Hygiene, Statistics and Public HealthCampus Bio‐Medico di Roma UniversityRomeItaly
| | - Luca Zinzula
- Department of Molecular Structural BiologyMax Planck Institute of BiochemistryMartinsriedGermany,Centro di Educazione Ambientale e alla Sostenibilità (CEAS) Laguna di NoraPulaItaly
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13
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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: 0] [Impact Index Per Article: 0] [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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14
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Genome-wide transcription start site mapping in the facultative intracellular pathogen Brucella melitensis by Capping-seq. Gene 2022; 844:146827. [PMID: 35995114 DOI: 10.1016/j.gene.2022.146827] [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: 04/11/2022] [Revised: 07/01/2022] [Accepted: 08/16/2022] [Indexed: 11/20/2022]
Abstract
Brucella melitensis (B. melitensis) is an important facultative intracellular bacterium that causes global zoonotic diseases. Continuous intracellular survival and replication are the main obstruction responsible for the accessibility of prevention and treatment of brucellosis. Bacteria respond to complex environment by regulating gene expression. Many regulatory factors function at loci where RNA polymerase initiates messenger RNA synthesis. However, limited gene annotation is a current obstacle for the research on expression regulation in bacteria. To improve annotation and explore potential functional sites, we proposed a novel genome-wide method called Capping-seq for transcription start site (TSS) mapping in B. melitensis. This technique combines capture of capped primary transcripts with Single Molecule Real-Time (SMRT) sequencing technology. We identified 2,369 TSSs at single nucleotide resolution by Capping-seq. TSSs analysis of Brucella transcripts showed a preference of purine on the TSS positions. Our results revealed that -35 and -10 elements of promoter contained consensus sequences of TTGNNN and TATNNN, respectively. The 5' ends analysis showed that 57% genes are associated with more than one TSS and 47% genes contain long leader regions, suggested potential complex regulation at the 5' ends of genes in B. melitensis. Moreover, we identified 52 leaderless genes that are mainly involved in the metabolic processes. Overall, Capping-seq technology provides a unique solution for TSS determination in prokaryotes. Our findings develop a systematic insight into the primary transcriptome characterization of B. melitensis. This study represents a critical basis for investigating gene regulation and pathogenesis of Brucella.
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15
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Tian M, Li Z, Qu J, Fang T, Yin Y, Zuo D, Abdelgawad HA, Hu H, Wang S, Qi J, Wang G, Yu S. The novel LysR-family transcriptional regulator BvtR is involved in the resistance of Brucella abortus to nitrosative stress, detergents and virulence through the genetic regulation of diverse pathways. Vet Microbiol 2022; 267:109393. [PMID: 35259600 DOI: 10.1016/j.vetmic.2022.109393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 01/22/2022] [Accepted: 02/28/2022] [Indexed: 11/22/2022]
Abstract
Brucella is a facultative intracellular bacterium lacking classical virulence factors; its virulence instead depends on its ability to invade and proliferate within host cells. After entering cells, Brucella rapidly modulates the expression of a series of genes involved in metabolism and immune evasion. Here, a novel LysR-family transcriptional regulator, designated Brucellavirulence-related transcriptional regulator (BvtR), was found to be associated with Brucella abortus virulence. We first successfully constructed a BvtR mutant, ΔbvtR, and a complemented strain, ΔbvtR-Com. Subsequently, we performed cell infection experiments, which indicated that the ΔbvtR strain exhibited similar adhesion, invasion and survival within HeLa cells or RAW264.7 macrophages to those of the wild-type strain. In stress resistance tests, the ΔbvtR strain showed enhanced sensitivity to sodium nitroprusside and sodium dodecyl sulfate, but not to hydrogen peroxide, cumene hydroperoxide, polymyxin B and natural serum. Mouse infection experiments indicated that the virulence of the ΔbvtR strain significantly decreased at 4 weeks post-infection. Finally, we analyzed differentially expressed genes regulated by BvtR with RNA-seq, COG classification and KEGG pathway analysis. Nitrogen metabolism, siderophore biosynthesis and oligopeptide transport were found to be the predominantly altered functions, and key metabolic and regulatory networks were delineated in the ΔbvtR mutant. Thus, we identified a novel Brucella virulence-related regulator, BvtR, and demonstrated that BvtR regulation affects Brucella resistance to killing by sodium nitroprusside and sodium dodecyl sulfate. The differentially expressed genes responding to BvtR are involved in diverse functions or pathways in Brucella, thus, suggesting the breadth of BvtR's regulatory functions. This study provides novel clues regarding Brucella pathogenesis.
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Affiliation(s)
- Mingxing Tian
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Zichen Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Jing Qu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China; Songjiang District Center for Animal Disease Control and Prevention, Shanghai 201699, China
| | - Tian Fang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China; College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, China
| | - Yi Yin
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Dong Zuo
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Hosny Ahmed Abdelgawad
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Hai Hu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Shaohui Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Jingjing Qi
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Guijun Wang
- College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, China
| | - Shengqing Yu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China.
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16
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Li Z, Wang S, Wei S, Yang G, Zhang C, Xi L, Zhang J, Cui Y, Hao J, Zhang H, Zhang H. Immunization with a combination of recombinant Brucella abortus proteins induces T helper immune response and confers protection against wild-type challenge in BALB/c mice. Microb Biotechnol 2022; 15:1811-1823. [PMID: 35166028 PMCID: PMC9151338 DOI: 10.1111/1751-7915.14015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 01/26/2022] [Accepted: 01/28/2022] [Indexed: 11/30/2022] Open
Abstract
Protective efficiency of a combination of four recombinant Brucella abortus (B. abortus) proteins, namely, ribosomal protein L7/L12, outer membrane protein (OMP) 22, OMP25 and OMP31, was evaluated as a combined subunit vaccine (CSV) against B. abortus infection in RAW 264.7 cell line and murine model. Four proteins were cloned, expressed and purified, and their immunocompetence was analysed. BALB/c mice were immunized subcutaneously with single subunit vaccines (SSVs) or CSV. Cellular and humoral immune responses were determined by ELISA. Results of immunoreactivity showed that these four recombinant proteins reacted with Brucella‐positive serum individually but not with Brucella‐negative serum. A massive production of IFN‐γ and IL‐2 but low degree of IL‐10 was observed in mice immunized with SSVs or CSV. In addition, the titres of IgG2a were heightened compared with IgG1 in SSV‐ or CSV‐immunized mice, which indicated that SSVs and CSV induced a typical T‐helper‐1‐dominated immune response in vivo. Further investigation of the CSV showed a superior protective effect in mice against brucellosis. The protection level induced by CSV was significantly higher than that induced by SSVs, which was not significantly different compared with a group immunized with RB51. Collectively, these antigens of Brucella could be potential candidates to develop subunit vaccines, and the CSV used in this study could be a potential candidate therapy for the prevention of brucellosis.
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Affiliation(s)
- Zhiqiang Li
- College of Biology and Food, Shangqiu Normal University, Shangqiu, Henan Provence, 476000, China
| | - Shuli Wang
- College of Biology and Food, Shangqiu Normal University, Shangqiu, Henan Provence, 476000, China
| | - Shujuan Wei
- College of Life Sciences, Henan Normal University, Xinxiang, Henan Province, 453007, China
| | - Guangli Yang
- College of Biology and Food, Shangqiu Normal University, Shangqiu, Henan Provence, 476000, China
| | - Chunmei Zhang
- College of Biology and Food, Shangqiu Normal University, Shangqiu, Henan Provence, 476000, China
| | - Li Xi
- College of Biology and Food, Shangqiu Normal University, Shangqiu, Henan Provence, 476000, China
| | - Jinliang Zhang
- College of Biology and Food, Shangqiu Normal University, Shangqiu, Henan Provence, 476000, China
| | - Yanyan Cui
- College of Biology and Food, Shangqiu Normal University, Shangqiu, Henan Provence, 476000, China
| | - Junfang Hao
- College of Biology and Food, Shangqiu Normal University, Shangqiu, Henan Provence, 476000, China
| | - Huan Zhang
- College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang Provence, 832003, China
| | - Hui Zhang
- College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang Provence, 832003, China
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17
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Yurgel SN, Qu Y, Rice JT, Ajeethan N, Zink EM, Brown JM, Purvine S, Lipton MS, Kahn ML. Specialization in a Nitrogen-Fixing Symbiosis: Proteome Differences Between Sinorhizobium medicae Bacteria and Bacteroids. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:1409-1422. [PMID: 34402628 DOI: 10.1094/mpmi-07-21-0180-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Using tandem mass spectrometry (MS/MS), we analyzed the proteome of Sinorhizobium medicae WSM419 growing as free-living cells and in symbiosis with Medicago truncatula. In all, 3,215 proteins were identified, over half of the open reading frames predicted from the genomic sequence. The abundance of 1,361 proteins displayed strong lifestyle bias. In total, 1,131 proteins had similar levels in bacteroids and free-living cells, and the low levels of 723 proteins prevented statistically significant assignments. Nitrogenase subunits comprised approximately 12% of quantified bacteroid proteins. Other major bacteroid proteins included symbiosis-specific cytochromes and FixABCX, which transfer electrons to nitrogenase. Bacteroids had normal levels of proteins involved in amino acid biosynthesis, glycolysis or gluconeogenesis, and the pentose phosphate pathway; however, several amino acid degradation pathways were repressed. This suggests that bacteroids maintain a relatively independent anabolic metabolism. Tricarboxylic acid cycle proteins were highly expressed in bacteroids and no other catabolic pathway emerged as an obvious candidate to supply energy and reductant to nitrogen fixation. Bacterial stress response proteins were induced in bacteroids. Many WSM419 proteins that are not encoded in S. meliloti Rm1021 were detected, and understanding the functions of these proteins might clarify why S. medicae WSM419 forms a more effective symbiosis with M. truncatula than S. meliloti Rm1021.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Svetlana N Yurgel
- Department of Plant, Food and Environmental Sciences, Faculty of Agriculture, Dalhousie University, P.O. Box 550, Truro, Nova Scotia, B2N 5E3, Canada
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, U.S.A
| | - Yi Qu
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, U.S.A
| | - Jennifer T Rice
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, U.S.A
| | - Nivethika Ajeethan
- Department of Plant, Food and Environmental Sciences, Faculty of Agriculture, Dalhousie University, P.O. Box 550, Truro, Nova Scotia, B2N 5E3, Canada
- Faculty of Technology, University of Jaffna, Sri Lanka
| | - Erika M Zink
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, U.S.A
| | - Joseph M Brown
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, U.S.A
| | - Sam Purvine
- Environmental Molecular Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, U.S.A
| | - Mary S Lipton
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, U.S.A
| | - Michael L Kahn
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, U.S.A
- School of Molecular Biosciences, Washington State University, Pullman, WA 99164-6340, U.S.A
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18
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Castillo-Zeledón A, Ruiz-Villalobos N, Altamirano-Silva P, Chacón-Díaz C, Barquero-Calvo E, Chaves-Olarte E, Guzmán-Verri C. A Sinorhizobium meliloti and Agrobacterium tumefaciens ExoR ortholog is not crucial for Brucella abortus virulence. PLoS One 2021; 16:e0254568. [PMID: 34388167 PMCID: PMC8362948 DOI: 10.1371/journal.pone.0254568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 06/29/2021] [Indexed: 11/19/2022] Open
Abstract
Brucella is a facultative extracellular-intracellular pathogen that belongs to the Alphaproteobacteria class. Precise sensing of environmental changes and a proper response mediated by a gene expression regulatory network are essential for this pathogen to survive. The plant-related Alphaproteobacteria Sinorhizobium meliloti and Agrobacterium tumefaciens also alternate from a free to a host-associated life, where a regulatory invasion switch is needed for this transition. This switch is composed of a two-component regulatory system (TCS) and a global inhibitor, ExoR. In B. abortus, the BvrR/BvrS TCS is essential for intracellular survival. However, the presence of a TCS inhibitor, such as ExoR, in Brucella is still unknown. In this work, we identified a genomic sequence similar to S. meliloti exoR in the B. abortus 2308W genome, constructed an exoR mutant strain, and performed its characterization through ex vivo and in vivo assays. Our findings indicate that ExoR is related to the BvrR phosphorylation state, and is related to the expression of known BvrR/BrvS gene targets, such as virB8, vjbR, and omp25 when grown in rich medium or starving conditions. Despite this, the exoR mutant strain showed no significant differences as compared to the wild-type strain, related to resistance to polymyxin B or human non-immune serum, intracellular replication, or infectivity in a mice model. ExoR in B. abortus is related to BvrR/BvrS as observed in other Rhizobiales; however, its function seems different from that observed for its orthologs described in A. tumefaciens and S. meliloti.
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Affiliation(s)
- Amanda Castillo-Zeledón
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional de Costa Rica, Heredia, Costa Rica
| | - Nazareth Ruiz-Villalobos
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional de Costa Rica, Heredia, Costa Rica
| | - Pamela Altamirano-Silva
- Centro de Investigación en Enfermedades Tropicales, Universidad de Costa Rica, San José, Costa Rica
| | - Carlos Chacón-Díaz
- Centro de Investigación en Enfermedades Tropicales, Universidad de Costa Rica, San José, Costa Rica
| | - Elías Barquero-Calvo
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional de Costa Rica, Heredia, Costa Rica
| | - Esteban Chaves-Olarte
- Centro de Investigación en Enfermedades Tropicales, Universidad de Costa Rica, San José, Costa Rica
| | - Caterina Guzmán-Verri
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional de Costa Rica, Heredia, Costa Rica
- * E-mail:
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19
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The ChvG-ChvI and NtrY-NtrX Two-Component Systems Coordinately Regulate Growth of Caulobacter crescentus. J Bacteriol 2021; 203:e0019921. [PMID: 34124942 DOI: 10.1128/jb.00199-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Two-component signaling systems (TCSs) are comprised of a sensory histidine kinase and a response regulator protein. In response to environmental changes, sensor kinases directly phosphorylate their cognate response regulator to affect gene expression. Bacteria typically express multiple TCSs that are insulated from one another and regulate distinct physiological processes. There are examples of cross-regulation between TCSs, but this phenomenon remains relatively unexplored. We have identified regulatory links between the ChvG-ChvI (ChvGI) and NtrY-NtrX (NtrYX) TCSs, which control important and often overlapping processes in alphaproteobacteria, including maintenance of the cell envelope. Deletion of chvG and chvI in Caulobacter crescentus limited growth in defined medium, and a selection for genetic suppressors of this growth phenotype uncovered interactions among chvGI, ntrYX, and ntrZ, which encodes a previously uncharacterized periplasmic protein. Significant overlap in the experimentally defined ChvI and NtrX transcriptional regulons provided support for the observed genetic connections between ntrYX and chvGI. Moreover, we present evidence that the growth defect of strains lacking chvGI is influenced by the phosphorylation state of NtrX and, to some extent, by levels of the TonB-dependent receptor ChvT. Measurements of NtrX phosphorylation in vivo indicated that NtrZ is an upstream regulator of NtrY and that NtrY primarily functions as an NtrX phosphatase. We propose a model in which NtrZ functions in the periplasm to inhibit NtrY phosphatase activity; regulation of phosphorylated NtrX levels by NtrZ and NtrY provides a mechanism to modulate and balance expression of the NtrX and ChvI regulons under different growth conditions. IMPORTANCE TCSs enable bacteria to regulate gene expression in response to physiochemical changes in their environment. The ChvGI and NtrYX TCSs regulate diverse pathways associated with pathogenesis, growth, and cell envelope function in many alphaproteobacteria. We used Caulobacter crescentus as a model to investigate regulatory connections between ChvGI and NtrYX. Our work defined the ChvI transcriptional regulon in C. crescentus and revealed a genetic interaction between ChvGI and NtrYX, whereby modulation of NtrYX signaling affects the survival of cells lacking ChvGI. In addition, we identified NtrZ as a periplasmic inhibitor of NtrY phosphatase activity in vivo. Our work establishes C. crescentus as an excellent model to investigate multilevel regulatory connections between ChvGI and NtrYX in alphaproteobacteria.
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20
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Li R, Liu W, Yin X, Zheng F, Wang Z, Wu X, Zhang X, Du Q, Huang Y, Tong D. Brucella spp. Omp25 Promotes Proteasome-Mediated cGAS Degradation to Attenuate IFN-β Production. Front Microbiol 2021; 12:702881. [PMID: 34394047 PMCID: PMC8358459 DOI: 10.3389/fmicb.2021.702881] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/22/2021] [Indexed: 11/13/2022] Open
Abstract
Type I interferons (IFN), a family of cytokines widely expressed in various tissues, play important roles in anti-infection immunity. Nevertheless, it is not known whether Brucella spp. could interfere with IFN-I production induced by other pathogens. This study investigated the regulatory roles of Brucella outer membrane protein (Omp)25 on the IFN-I signaling pathway and found that Omp25 inhibited the production of IFN-β and its downstream IFN-stimulated genes induced by various DNA viruses or IFN-stimulatory DNA in human, murine, porcine, bovine, and ovine monocyte/macrophages or peripheral blood mononuclear cells. Brucella Omp25 suppressed the phosphorylation of stimulator of IFN genes (STINGs) and IFN regulatory factor 3 and nuclear translocation of phosphorylated IFN regulatory factor 3 in pseudorabies virus- or herpes simplex virus-1-infected murine, human, or porcine macrophages. Furthermore, we found that Brucella Omp25 promoted cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS) degradation via the proteasome-dependent pathway, resulting in a decreased cyclic guanosine monophosphate-adenosine monophosphate production and downstream signaling activation upon DNA virus infection or IFN-stimulatory DNA stimulation. Mapping the predominant function domain of Omp25 showed that the amino acids 161 to 184 of Omp25 were required for Omp25-induced cGAS degradation, among which five amino acid residues (R176, Y179, R180, Y181, and Y184) were required for the inhibitory effect of Omp25 on IFN-β induction. Altogether, our results demonstrated that Brucella Omp25 inhibits cGAS STING signaling pathway-induced IFN-β via facilitating the ubiquitin-proteasome-dependent degradation of cGAS in various mammalian monocyte/macrophages.
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Affiliation(s)
- Ruizhen Li
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Wenli Liu
- School Hospital, Northwest A&F University, Yangling, China
| | - Xiangrui Yin
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Fangfang Zheng
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Zhenyu Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Xingchen Wu
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Xiaohua Zhang
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Qian Du
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Yong Huang
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Dewen Tong
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
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21
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Shirdast H, Ebrahimzadeh F, Taromchi AH, Mortazavi Y, Esmaeilzadeh A, Sekhavati MH, Nedaei K, Mirabzadeh E. Recombinant Lactococcus Lactis Displaying Omp31 Antigen of Brucella melitensis Can Induce an Immunogenic Response in BALB/c Mice. Probiotics Antimicrob Proteins 2021; 13:80-89. [PMID: 32661939 DOI: 10.1007/s12602-020-09684-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Since Brucella infection mostly occurs through the mucosal surfaces, immune response induced by vaccine that is delivered by a way of mucosal route can be drastically enhanced to control the brucellosis. Omp31is the major outer membrane protein of Brucella, and is considered as a protective antigen against Brucella infection. Accordingly, Lactococcus lactis has been used as an antigen-delivering vector to develop a vaccine-induced mucosal response for having a safer vaccination against brucellosis. A designed omp31 gene fused to the usp45 signal peptide and M6 cell wall anchor was sub cloned in the pNZ7021 expression vector, and a recombinant L. lactis displaying Omp31 was constructed. Omp31 protein expression was confirmed using Western blotting and immunofluorescence analysis. Animals were orally and intraperitoneally immunized with live or killed L. lactis expressing Omp31, respectively. The humoral and cellular immune responses were evaluated by measuring the specific cytokines and antibodies. sIgA, serum IgA, IgM, and total IgG antibodies significantly increased in the mice immunized with live recombinant L. lactis expressing Omp31 and also serum IgM, and total IgG antibodies significantly increased in mice immunized with killed recombinant L. lactis expressing Omp31. Among IgG subtypes, IgG2a response was significantly higher in both groups compared to IgG1. In mice groups immunized with recombinant L. lactis, the IFN-γ and IL-10 level elevated; however, there was no change in the level of IL-4. These results indicated that recombinants L. lactis induce both humoral and cellular immune responses in mice, and also vaccines based on L. lactis-derived live carriers are promising interventions against Brucella melitensis infections.
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Affiliation(s)
- Hoda Shirdast
- Department of Medical Biotechnology, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Fatemeh Ebrahimzadeh
- Department of Medical Biotechnology, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Amir Hossein Taromchi
- Department of Medical Biotechnology, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran. .,Cancer Gene Therapy Research Center, Zanjan University of Medical Sciences, Zanjan, Iran.
| | - Yousef Mortazavi
- Department of Medical Biotechnology, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran.,Cancer Gene Therapy Research Center, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Abdolreza Esmaeilzadeh
- Cancer Gene Therapy Research Center, Zanjan University of Medical Sciences, Zanjan, Iran.,Department of Immunology, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
| | | | - Keivan Nedaei
- Department of Medical Biotechnology, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Esmat Mirabzadeh
- Department of Molecular Medicine, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
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22
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Canine brucellosis in Costa Rica reveals widespread Brucella canis infection and the recent introduction of foreign strains. Vet Microbiol 2021; 257:109072. [PMID: 33965789 DOI: 10.1016/j.vetmic.2021.109072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 04/13/2021] [Indexed: 01/31/2023]
Abstract
Brucellosis is a prevalent disease in Costa Rica (CR), with an increasing number of human infections. Close to half of homes in CR have one or more dogs, corresponding to ∼1.4 million canines, most of them in the Central Valley within or near the cities of San José, Heredia, and Alajuela. From 302 dog sera collected from this region, 19 were positive for Brucella canis antigens, and five had antibodies against smooth lipopolysaccharide, suggesting infections by both B. canis and other Brucella species. B. canis strains were isolated in the Central Valley from 26 kennel dogs and three pet dogs, all displaying clinical signs of canine brucellosis. We detected three recent introductions of different B. canis strains in kennels: two traced from Mexico and one from Panama. Multiple locus-variable number tandem repeats (MLVA-16) and whole-genome sequencing (WGSA) analyses showed that B. canis CR strains comprise three main lineages. The tree topologies obtained by WGSA and MLVA-16 just partially agreed, indicating that the latter analysis is not suitable for phylogenetic studies. The fatty acid methyl ester analysis resolved five different B. canis groups, showing less resolution power than the MLVA-16 and WGSA. Lactobacillic acid was absent in linages I and II but present in linage III, supporting the recent introductions of B. canis strains from Mexico. B. canis displaying putative functional cyclopropane synthase for the synthesis of lactobacillic acid are phylogenetically intertwined with B. canis with non-functional protein, indicating that mutations have occurred independently in the various lineages.
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23
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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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24
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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: 45] [Impact Index Per Article: 15.0] [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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25
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González-Espinoza G, Arce-Gorvel V, Mémet S, Gorvel JP. Brucella: Reservoirs and Niches in Animals and Humans. Pathogens 2021; 10:pathogens10020186. [PMID: 33572264 PMCID: PMC7915599 DOI: 10.3390/pathogens10020186] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 02/02/2021] [Accepted: 02/05/2021] [Indexed: 01/18/2023] Open
Abstract
Brucella is an intracellular bacterium that causes abortion, reproduction failure in livestock and leads to a debilitating flu-like illness with serious chronic complications if untreated in humans. As a successful intracellular pathogen, Brucella has developed strategies to avoid recognition by the immune system of the host and promote its survival and replication. In vivo, Brucellae reside mostly within phagocytes and other cells including trophoblasts, where they establish a preferred replicative niche inside the endoplasmic reticulum. This process is central as it gives Brucella the ability to maintain replicating-surviving cycles for long periods of time, even at low bacterial numbers, in its cellular niches. In this review, we propose that Brucella takes advantage of the environment provided by the cellular niches in which it resides to generate reservoirs and disseminate to other organs. We will discuss how the favored cellular niches for Brucella infection in the host give rise to anatomical reservoirs that may lead to chronic infections or persistence in asymptomatic subjects, and which may be considered as a threat for further contamination. A special emphasis will be put on bone marrow, lymph nodes, reproductive and for the first time adipose tissues, as well as wildlife reservoirs.
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26
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Jiao H, Luo Y, Zhou Z, Gu G, Li B, Li W, Liu Y, Wang Y, Wang X, Zhao Y, Wu L, Chen J, Shuai X, Huang Q. Integrative Bioinformatics Indentification of the Autophagic Pathway-Associated miRNA-mRNA Networks in RAW264.7 Macrophage Cells Infected with ∆Omp25 Brucella melitensis. Inflammation 2021; 43:532-539. [PMID: 31807961 DOI: 10.1007/s10753-019-01135-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Brucellosis is a zoonotic infectious disease caused by Brucella infection. Outer membrane protein 25 (Omp25) is closely related to the virulence and immunogenicity of Brucella. However, the molecular mechanism of Omp25 affecting Brucella-mediated macrophage autophagy remains unclear. Our previous study reported that four miRNAs (the upregulation of mmu-miR-146a-5p and mmu-miR-155-5p and downregulation of mmu-miR-149-3p and mmu-miR-5126) were confirmed and revealed the differentially expressed genes (DEGs) profile in RAW264.7 macrophage cells infected with Brucella melitensis Omp25 deletion mutant (∆Omp25 B. melitensis). Here, we predicted the target genes of the four miRNAs by TargetScan, miRanda, and PicTar. GO and KEGG were used for functional enrichment analysis of DEGs profile to reveal the autophagic pathway-associated genes. The overlapped genes, which drawn the autophagic pathway-associated miRNA-mRNA networks by cytoscape software, were identified by intersecting with the predicted target genes and autophagic pathway-associated DEGs. qRT-PCR was performed to validate the mRNAs of networks. The results showed that the autophagic pathway-associated networks of mmu-miR-149-3p-Ptpn5, mmu-miR-149-3p-Ppp2r3c, and mmu-miR-146a-5p-Dusp16 were identified in RAW264.7 macrophage cells infected with ∆Omp25 B. melitensis. Our findings are of great significance in elucidating the function of Omp25, revealing the infection mechanism of Brucella and prophylaxising and treating brucellosis.
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Affiliation(s)
- Hanwei Jiao
- Veterinary Scientific Engineering Research Center, College of Animal Science, Southwest University, Chongqing, 402460, People's Republic of China.
| | - Yichen Luo
- Veterinary Scientific Engineering Research Center, College of Animal Science, Southwest University, Chongqing, 402460, People's Republic of China
| | - Zhixiong Zhou
- Veterinary Scientific Engineering Research Center, College of Animal Science, Southwest University, Chongqing, 402460, People's Republic of China
| | - Guojing Gu
- Veterinary Scientific Engineering Research Center, College of Animal Science, Southwest University, Chongqing, 402460, People's Republic of China
| | - Bowen Li
- Veterinary Scientific Engineering Research Center, College of Animal Science, Southwest University, Chongqing, 402460, People's Republic of China
| | - Wenjie Li
- Veterinary Scientific Engineering Research Center, College of Animal Science, Southwest University, Chongqing, 402460, People's Republic of China
| | - Yuxuan Liu
- Veterinary Scientific Engineering Research Center, College of Animal Science, Southwest University, Chongqing, 402460, People's Republic of China
| | - Yidan Wang
- Veterinary Scientific Engineering Research Center, College of Animal Science, Southwest University, Chongqing, 402460, People's Republic of China
| | - Xinglong Wang
- Veterinary Scientific Engineering Research Center, College of Animal Science, Southwest University, Chongqing, 402460, People's Republic of China
| | - Yu Zhao
- Veterinary Scientific Engineering Research Center, College of Animal Science, Southwest University, Chongqing, 402460, People's Republic of China
| | - Li Wu
- Veterinary Scientific Engineering Research Center, College of Animal Science, Southwest University, Chongqing, 402460, People's Republic of China
| | - Jixuan Chen
- Veterinary Scientific Engineering Research Center, College of Animal Science, Southwest University, Chongqing, 402460, People's Republic of China
| | - Xuehong Shuai
- Veterinary Scientific Engineering Research Center, College of Animal Science, Southwest University, Chongqing, 402460, People's Republic of China
| | - Qingzhou Huang
- Veterinary Scientific Engineering Research Center, College of Animal Science, Southwest University, Chongqing, 402460, People's Republic of China
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27
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Ji X, Lu P, Xue J, Zhao N, Zhang Y, Dong L, Zhang X, Li P, Hu Y, Wang J, Zhang B, Liu J, Lv H, Wang S. The lipoprotein NlpD in Cronobacter sakazakii responds to acid stress and regulates macrophage resistance and virulence by maintaining membrane integrity. Virulence 2021; 12:415-429. [PMID: 33459158 PMCID: PMC7834084 DOI: 10.1080/21505594.2020.1870336] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Cronobacter sakazakii, an emerging opportunistic pathogen, is implicated in severe foodborne outbreak infections in premature and full-term infants. Generally, acid tolerance is vital for the pathogenesis of foodborne pathogens; however, its role in C. sakazakii virulence remains largely unknown. To screen out acid-tolerance determinants from transposon mutants, anovel counterselection method using gentamicin and acid was developed. Using the counterselection method and growth assay, we screened several acid-sensitive mutants and found that nlpD encodes an acid-resistance factor in C. sakazakii. Compared to the wild-type strain, the nlpD mutant exhibited attenuated virulence in a rat model. Using macrophage THP-1 cells and a pH probe, we verified that nlpD enables bacteria to resist macrophages by resisting acidification. Finally, we confirmed that nlpD maintains C. sakazakii membrane integrity in acid using propidium iodide permeabilization assays via flow cytometry. Our results confirm that nlpD is a novel virulence factor that permits C. sakazakii to survive under acid stress conditions. Considering that NlpD is a conserved lipoprotein located in the bacterial outer membrane, NlpD could be used as a target for drug development.
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Affiliation(s)
- Xuemeng Ji
- Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University , Tianjin, China
| | - Ping Lu
- Institute of Radiation Medicine, Chinese Academy of Medical Science and Peking Union Medical Collage , Tianjin, China
| | - Juan Xue
- Institute of Infection and Immunity, Taihe Hospital, Hubei University of Medicine , Shiyan, China
| | - Ning Zhao
- Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University , Tianjin, China
| | - Yan Zhang
- Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University , Tianjin, China
| | - Lu Dong
- Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University , Tianjin, China
| | - Xuejiao Zhang
- Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University , Tianjin, China
| | - Ping Li
- Key Laboratory of Food Nutrition and Safety, Ministry of Education, Tianjin University of Science and Technology , Tianjin, China
| | - Yaozhong Hu
- Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University , Tianjin, China
| | - Jin Wang
- Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University , Tianjin, China
| | - Bowei Zhang
- Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University , Tianjin, China
| | - Jingmin Liu
- Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University , Tianjin, China
| | - Huan Lv
- Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University , Tianjin, China
| | - Shuo Wang
- Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University , Tianjin, China
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Rajendhran J. Genomic insights into Brucella. INFECTION GENETICS AND EVOLUTION 2020; 87:104635. [PMID: 33189905 DOI: 10.1016/j.meegid.2020.104635] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 11/09/2020] [Accepted: 11/11/2020] [Indexed: 01/21/2023]
Abstract
Brucellosis is a zoonotic disease caused by certain species of Brucella. Each species has its preferred host animal, though it can infect other animals too. For a longer period, only six classical species were recognized in the genus Brucella. No vaccine is available for human brucellosis. Therefore, human brucellosis can be controlled only by controlling brucellosis in animals. The genus is now expanding with the newly isolated atypical strains from various animals, including marine mammals. Presently, 12 species of Brucella have been recognized. The first genome of Brucella was released in 2002, and today, we have more than 1500 genomes of Brucella spp. isolated worldwide. Multiple genome sequences are available for the major zoonotic species, B. abortus, B. melitensis, and B. suis. The Brucella genome has two chromosomes with the approximate sizes of 2.1 and 1.2 Mbp. The genome of Brucella is highly conserved across all the species at the nucleotide level. One of the unanswered questions is what makes host preference in different species of Brucella. Here, I summarize the recent advancements in the Brucella genomics research.
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Affiliation(s)
- Jeyaprakash Rajendhran
- Department of Genetics, School of Biological Sciences, Madurai Kamaraj University, Madurai 625021, Tamil Nadu, India.
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29
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Brucella abortus Depends on l-Serine Biosynthesis for Intracellular Proliferation. Infect Immun 2020; 88:IAI.00840-19. [PMID: 31740531 DOI: 10.1128/iai.00840-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 11/11/2019] [Indexed: 01/15/2023] Open
Abstract
l-Serine is a nonessential amino acid and a key intermediate in several relevant metabolic pathways. In bacteria, the major source of l-serine is the phosphorylated pathway, which comprises three enzymes: d-3-phosphoglycerate dehydrogenase (PGDH; SerA), phosphoserine amino transferase (PSAT; SerC), and l-phosphoserine phosphatase (PSP; SerB). The Brucella abortus genome encodes two PGDHs (SerA-1 and SerA-2), involved in the first step in l-serine biosynthesis, and one PSAT and one PSP, responsible for the second and third steps, respectively. In this study, we demonstrate that the serA1 serA2 double mutant and the serC and serB single mutants are auxotrophic for l-serine. These auxotrophic mutants can be internalized but are unable to replicate in HeLa cells and in J774A.1 macrophage-like cells. Replication defects of auxotrophic mutants can be reverted by cell medium supplementation with l-serine at early times postinfection. In addition, the serB mutant is attenuated in the murine intraperitoneal infection model and has an altered lipid composition, since the lack of l-serine abrogates phosphatidylethanolamine synthesis in this strain. Taken together, these results reveal that limited availability of l-serine within the host cell impairs proliferation of the auxotrophic strains, highlighting the relevance of this biosynthetic pathway in Brucella pathogenicity.
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30
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Ramírez-González EA, Moreno-Lafont MC, Méndez-Tenorio A, Cancino-Díaz ME, Estrada-García I, López-Santiago R. Prediction of Structure and Molecular Interaction with DNA of BvrR, a Virulence-Associated Regulatory Protein of Brucella. Molecules 2019; 24:E3137. [PMID: 31470504 PMCID: PMC6749498 DOI: 10.3390/molecules24173137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 08/10/2019] [Accepted: 08/23/2019] [Indexed: 11/28/2022] Open
Abstract
Brucellosis, also known as "undulant fever" is a zoonotic disease caused by Brucella, which is a facultative intracellular bacterium. Despite efforts to eradicate this disease, infection in uncontrolled domestic animals persists in several countries and therefore transmission to humans is common. Brucella evasion of the innate immune system depends on its ability to evade the mechanisms of intracellular death in phagocytic cells. The BvrR-BvrS two-component system allows the bacterium to detect adverse conditions in the environment. The BvrS protein has been associated with genes of virulence factors, metabolism, and membrane transport. In this study, we predicted the DNA sequence recognized by BvrR with Gibbs Recursive Sampling and identified the three-dimensional structure of BvrR using I-TASSER suite, and the interaction mechanism between BvrR and DNA with Protein-DNA docking and molecular dynamics (MD) simulation. Based on the Gibbs recursive Sampling analysis, we found the motif AAHTGC (H represents A, C, and T nucleotides) as a possible sequence recognized by BvrR. The docking and EMD simulation results showed that C-terminal effector domain of BvrR protein is likely to interact with AAHTGC sequence. In conclusion, we predicted the structure, recognition motif, and interaction of BvrR with DNA.
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Affiliation(s)
- Edgar A Ramírez-González
- Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México 11340, Mexico
| | - Martha C Moreno-Lafont
- Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México 11340, Mexico
| | - Alfonso Méndez-Tenorio
- Laboratorio de Biotecnología y Bioinformática Genómica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México 11340, Mexico
| | - Mario E Cancino-Díaz
- Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México 11340, Mexico
| | - Iris Estrada-García
- Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México 11340, Mexico
| | - Rubén López-Santiago
- Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México 11340, Mexico.
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31
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López-Santiago R, Sánchez-Argáez AB, De Alba-Núñez LG, Baltierra-Uribe SL, Moreno-Lafont MC. Immune Response to Mucosal Brucella Infection. Front Immunol 2019; 10:1759. [PMID: 31481953 PMCID: PMC6710357 DOI: 10.3389/fimmu.2019.01759] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 07/11/2019] [Indexed: 01/18/2023] Open
Abstract
Brucellosis is one of the most prevalent bacterial zoonosis of worldwide distribution. The disease is caused by Brucella spp., facultative intracellular pathogens. Brucellosis in animals results in abortion of fetuses, while in humans, it frequently manifests flu-like symptoms and a typical undulant fever, being osteoarthritis a common complication of the chronic infection. The two most common ways to acquire the infection in humans are through the ingestion of contaminated dairy products or by inhalation of contaminated aerosols. Brucella spp. enter the body mainly through the gastrointestinal and respiratory mucosa; however, most studies of immune response to Brucella spp. are performed analyzing models of systemic immunity. It is necessary to better understand the mucosal immune response induced by Brucella infection since this is the main entry site for the bacterium. In this review, some virulence factors and the mechanisms needed for pathogen invasion and persistence are discussed. Furthermore, some aspects of local immune responses induced during Brucella infection will be reviewed. With this knowledge, better vaccines can be designed focused on inducing protective mucosal immune response.
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Affiliation(s)
- Rubén López-Santiago
- Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Ana Beatriz Sánchez-Argáez
- Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Liliana Gabriela De Alba-Núñez
- Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | | | - Martha Cecilia Moreno-Lafont
- Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
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Herrou J, Willett JW, Fiebig A, Varesio LM, Czyż DM, Cheng JX, Ultee E, Briegel A, Bigelow L, Babnigg G, Kim Y, Crosson S. Periplasmic protein EipA determines envelope stress resistance and virulence in Brucella abortus. Mol Microbiol 2019; 111:637-661. [PMID: 30536925 DOI: 10.1111/mmi.14178] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/30/2018] [Indexed: 12/17/2022]
Abstract
Molecular components of the Brucella abortus cell envelope play a major role in its ability to infect, colonize and survive inside mammalian host cells. In this study, we have defined a role for a conserved gene of unknown function in B. abortus envelope stress resistance and infection. Expression of this gene, which we name eipA, is directly activated by the essential cell cycle regulator, CtrA. eipA encodes a soluble periplasmic protein that adopts an unusual eight-stranded β-barrel fold. Deletion of eipA attenuates replication and survival in macrophage and mouse infection models, and results in sensitivity to treatments that compromise the cell envelope integrity. Transposon disruption of genes required for LPS O-polysaccharide biosynthesis is synthetically lethal with eipA deletion. This genetic connection between O-polysaccharide and eipA is corroborated by our discovery that eipA is essential in Brucella ovis, a naturally rough species that harbors mutations in several genes required for O-polysaccharide production. Conditional depletion of eipA expression in B. ovis results in a cell chaining phenotype, providing evidence that eipA directly or indirectly influences cell division in Brucella. We conclude that EipA is a molecular determinant of Brucella virulence that functions to maintain cell envelope integrity and influences cell division.
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Affiliation(s)
- Julien Herrou
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Jonathan W Willett
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Aretha Fiebig
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Lydia M Varesio
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Daniel M Czyż
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, USA
| | - Jason X Cheng
- Department of Pathology, The University of Chicago, Chicago, IL, USA
| | - Eveline Ultee
- Department of Biology, Universiteit Leiden, Leiden, Netherlands
| | - Ariane Briegel
- Department of Biology, Universiteit Leiden, Leiden, Netherlands
| | - Lance Bigelow
- Biosciences Division, Argonne National Laboratory, Argonne, IL, USA
| | - Gyorgy Babnigg
- Biosciences Division, Argonne National Laboratory, Argonne, IL, USA
| | - Youngchang Kim
- Biosciences Division, Argonne National Laboratory, Argonne, IL, USA
| | - Sean Crosson
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
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Chen B, Liu B, Zhao Z, Wang G. Evaluation of a DNA vaccine encoding Brucella BvrR in BALB/c mice. Mol Med Rep 2018; 19:1302-1308. [PMID: 30569140 DOI: 10.3892/mmr.2018.9735] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 07/06/2018] [Indexed: 11/05/2022] Open
Abstract
Brucellosis is an important neglected zoonotic disease, and the pathogens responsible are Brucellae. In order to evaluate the immunogenicity and protective efficacy of a DNA vaccine encoding Brucella BvrR, the recombinant plasmid pCDNA‑BvrR was constructed by inserting the BvrR gene fragment into a pCDNA3.0 vector. The His6‑tagged BvrR was purified with His‑trap FF crude affinity chromatography and verified with an anti‑histidine monoclonal antibody by western blot analysis. The specific immunoglobulin antigens and their isotypes were detected by indirect ELISA. The recombinant His6‑BvrR protein was expressed and purified by affinity chromatography. The optical density 450 value of immunoglobulin G (IgG) in the pCDNA‑BvrR group was significantly increased compared with the pCDNA3.0 vector or PBS groups (P<0.05), and the pCDNA3.0 vector and PBS groups exhibited no significant difference (P>0.05). BvrR induced specific antibodies with a dominance of IgG2a over IgG1 and the T cell‑proliferative response, in addition to a typical T helper‑1 (Th1)‑dominated immune response in mice. The splenocytes from mice of the pCDNA‑BvrR group demonstrated significant proliferative activity compared with the pCDNA3.0 vector group. The present results indicated that immunization with BvrR induced a specific Th1‑type immune response in mice. Subsequent to challenging with B. abortus S19, it was identified that the DNA vaccine pCDNA‑BvrR induced a significant level of protection in BALB/c mice by evaluating systemic bacterial clearance. These results suggested that BvrR may be a good candidate for a DNA vaccine against brucellosis.
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Affiliation(s)
- Bo Chen
- Department of Pathogenic Biology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Baoshan Liu
- College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, Liaoning 110866, P.R. China
| | - Zhina Zhao
- Department of Microbiology and Cell Biology, College of Life Science and Pharmaceuticals, Shenyang Pharmaceutical University, Shenyang, Liaoning 110016, P.R. China
| | - Guizhen Wang
- Department of Pathogenic Biology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning 110122, P.R. China
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Molecular mechanisms of polymyxin resistance and detection of mcr genes. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2018; 163:28-38. [PMID: 30439931 DOI: 10.5507/bp.2018.070] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 10/26/2018] [Indexed: 12/12/2022] Open
Abstract
Antibiotic resistance is an ever-increasing global problem. Major commercial antibiotics often fail to fight common bacteria, and some pathogens have become multi-resistant. Polymyxins are potent bactericidal antibiotics against gram-negative bacteria. Known resistance to polymyxin includes intrinsic, mutational and adaptive mechanisms, with the recently described horizontally acquired resistance mechanisms. In this review, we present several strategies for bacteria to develop enhanced resistance to polymyxins, focusing on changes in the outer membrane, efflux and other resistance determinants. Better understanding of the genes involved in polymyxin resistance may pave the way for the development of new and effective antimicrobial agents. We also report novel in silico tested primers for PCR assay that may be able distinguish colistin-resistant isolates carrying the plasmid-encoded mcr genes and will assist in combating the spread of colistin resistance in bacteria.
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Maarsingh JD, Haydel SE. Mycobacterium smegmatis PrrAB two-component system influences triacylglycerol accumulation during ammonium stress. Microbiology (Reading) 2018; 164:1276-1288. [DOI: 10.1099/mic.0.000705] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Affiliation(s)
- Jason D. Maarsingh
- 1School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Shelley E. Haydel
- 2Biodesign Institute Center for Immunotherapy, Vaccines and Virotherapy, Arizona State University, Tempe, AZ 85287, USA
- 1School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
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Park WB, Im YB, Shim S, Yoo HS. Analysis of protein expression in Brucella abortus mutants with different growth rates by two-dimensional gel electrophoresis and LC-MS/MS peptide analysis. J Vet Sci 2018; 19:216-231. [PMID: 29032658 PMCID: PMC5879070 DOI: 10.4142/jvs.2018.19.2.216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 09/12/2017] [Accepted: 09/22/2017] [Indexed: 11/20/2022] Open
Abstract
Brucella abortus is a bacterium that causes brucellosis and is the causative agent of worldwide zoonoses. Pathogenesis of the B. abortus infection is complicated, and several researchers have attempted to elucidate the infection mechanism of B. abortus. While several proteins have been revealed as pathogenic factors by previous researchers, the underlying mechanism of B. abortus infection is unresolved. In this study, we identified proteins showing different expression levels in B. abortus mutants with different biological characteristics that were generated by random insertion of a transposon. Five mutants were selected based on biological characteristics, in particular, their growth features. Total proteins of mutant and wild-type B. abortus were purified and subjected to two-dimensional gel electrophoresis. Thirty protein spots of each mutant with expression increases or decreases were selected; those with a change of more than 2-fold were compared with the wild-type. Selected spots underwent liquid chromatography tandem mass spectrometry for peptide analysis. DnaK and ClpB, involved in protein aggregation, increased. SecA and GAPDH, associated with energy metabolism, decreased in some mutants with a growth rate slower than that of the wild-type. Mutants with slower growth showed a decrease in energy metabolism-related proteins, while mutants with faster growth showed an increase in pathogenicity-related proteins.
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Affiliation(s)
- Woo Bin Park
- Department of Infectious Diseases, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
| | - Young Bin Im
- Department of Infectious Diseases, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
| | - Soojin Shim
- Department of Infectious Diseases, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
| | - Han Sang Yoo
- Department of Infectious Diseases, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea.,Institute of Green-Bio Science and Technology, Seoul National University, Pyeongchang 25354, Korea
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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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Dual phosphorylation in response regulator protein PrrA is crucial for intracellular survival of mycobacteria consequent upon transcriptional activation. Biochem J 2017; 474:4119-4136. [PMID: 29101285 DOI: 10.1042/bcj20170596] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 11/02/2017] [Accepted: 11/03/2017] [Indexed: 01/05/2023]
Abstract
The remarkable ability of Mycobacterium tuberculosis (Mtb) to survive inside human macrophages is attributed to the presence of a complex sensory and regulatory network. PrrA is a DNA-binding regulatory protein, belonging to an essential two-component system (TCS), PrrA/B, which is required for early phase intracellular replication of Mtb. Despite its importance, the mechanism of PrrA/B-mediated signaling is not well understood. In the present study, we demonstrate that the binding of PrrA on the promoter DNA and its consequent activation is cumulatively controlled via dual phosphorylation of the protein. We have further characterized the role of terminal phospho-acceptor domain in the physical interaction of PrrA with its cognate kinase PrrB. The genetic deletion of prrA/B in Mycobacterium smegmatis was possible only in the presence of ectopic copies of the genes, suggesting the essentiality of this TCS in fast-growing mycobacterial strains as well. The overexpression of phospho-mimetic mutant (T6D) altered the growth of M. smegmatis in an in vitro culture and affected the replication of Mycobacterium bovis BCG in mouse peritoneal macrophages. Interestingly, the Thr6 site was found to be conserved in Mtb complex, whereas it was altered in some fast-growing mycobacterial strains, indicating that this unique phosphorylation might be predominant in employing the regulatory circuit in M. bovis BCG and presumably also in Mtb complex.
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Hop HT, Arayan LT, Reyes AWB, Huy TXN, Min W, Lee HJ, Son JS, Kim S. Simultaneous RNA-seq based transcriptional profiling of intracellular Brucella abortus and B. abortus-infected murine macrophages. Microb Pathog 2017; 113:57-67. [PMID: 29054743 DOI: 10.1016/j.micpath.2017.10.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Revised: 10/15/2017] [Accepted: 10/16/2017] [Indexed: 02/06/2023]
Abstract
Brucella is a zoonotic pathogen that survives within macrophages; however the replicative mechanisms involved are not fully understood. We describe the isolation of sufficient Brucella abortus RNA from primary host cell environment using modified reported methods for RNA-seq analysis, and simultaneously characterize the transcriptional profiles of intracellular B. abortus and bone marrow-derived macrophages (BMM) from BALB/c mice at 24 h (replicative phase) post-infection. Our results revealed that 25.12% (801/3190) and 16.16% (515/3190) of the total B. abortus genes were up-regulated and down-regulated at >2-fold, respectively as compared to the free-living B. abortus. Among >5-fold differentially expressed genes, the up-regulated genes are mostly involved in DNA, RNA manipulations as well as protein biosynthesis and secretion while the down-regulated genes are mainly involved in energy production and metabolism. On the other hand, the host responses during B. abortus infection revealed that 14.01% (6071/43,346) of BMM genes were reproducibly transcribed at >5-fold during infection. Transcription of cytokines, chemokines and transcriptional factors, such as tumor necrosis factor (Tnf), interleukin-1α (Il1α), interleukin-1β (Il1β), interleukin-6 (Il6), interleukin-12 (Il12), chemokine C-X-C motif (CXCL) family, nuclear factor kappa B (Nf-κb), signal transducer and activator of transcription 1 (Stat1), that may contribute to host defense were markedly induced while transcription of various genes involved in cell proliferation and metabolism were suppressed upon B. abortus infection. In conclusion, these data suggest that Brucella modulates gene expression in hostile intracellular environment while simultaneously alters the host pathways that may lead to the pathogen's intracellular survival and infection.
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Affiliation(s)
- Huynh Tan Hop
- Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju 660-701, Republic of Korea
| | - Lauren Togonon Arayan
- Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju 660-701, Republic of Korea
| | | | - Tran Xuan Ngoc Huy
- Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju 660-701, Republic of Korea
| | - WonGi Min
- Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju 660-701, Republic of Korea
| | - Hu Jang Lee
- Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju 660-701, Republic of Korea
| | - Jee Soo Son
- iNtRON Biotechnology, Inc., Room 903, JungAng Induspia, 137, Sagimakgol-ro, Jungwon-gu, Seongnam, Gyeonggi-do 13202, Republic of Korea
| | - Suk Kim
- Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju 660-701, Republic of Korea; Institute of Agriculture and Life Science, Gyeongsang National University, Jinju 660-701, Republic of Korea.
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Rossetti CA, Drake KL, Lawhon SD, Nunes JS, Gull T, Khare S, Adams LG. Systems Biology Analysis of Temporal In vivo Brucella melitensis and Bovine Transcriptomes Predicts host:Pathogen Protein-Protein Interactions. Front Microbiol 2017; 8:1275. [PMID: 28798726 PMCID: PMC5529337 DOI: 10.3389/fmicb.2017.01275] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 06/26/2017] [Indexed: 01/13/2023] Open
Abstract
To date, fewer than 200 gene-products have been identified as Brucella virulence factors, and most were characterized individually without considering how they are temporally and coordinately expressed or secreted during the infection process. Here, we describe and analyze the in vivo temporal transcriptional profile of Brucella melitensis during the initial 4 h interaction with cattle. Pathway analysis revealed an activation of the "Two component system" providing evidence that the in vivo Brucella sense and actively regulate their metabolism through the transition to an intracellular lifestyle. Contrarily, other Brucella pathways involved in virulence such as "ABC transporters" and "T4SS system" were repressed suggesting a silencing strategy to avoid stimulation of the host innate immune response very early in the infection process. Also, three flagellum-encoded loci (BMEII0150-0168, BMEII1080-1089, and BMEII1105-1114), the "flagellar assembly" pathway and the cell components "bacterial-type flagellum hook" and "bacterial-type flagellum" were repressed in the tissue-associated B. melitensis, while RopE1 sigma factor, a flagellar repressor, was activated throughout the experiment. These results support the idea that Brucella employ a stealthy strategy at the onset of the infection of susceptible hosts. Further, through systems-level in silico host:pathogen protein-protein interactions simulation and correlation of pathogen gene expression with the host gene perturbations, we identified unanticipated interactions such as VirB11::MAPK8IP1; BtaE::NFKBIA, and 22 kDa OMP precursor::BAD and MAP2K3. These findings are suggestive of new virulence factors and mechanisms responsible for Brucella evasion of the host's protective immune response and the capability to maintain a dormant state. The predicted protein-protein interactions and the points of disruption provide novel insights that will stimulate advanced hypothesis-driven approaches toward revealing a clearer understanding of new virulence factors and mechanisms influencing the pathogenesis of brucellosis.
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Affiliation(s)
- Carlos A Rossetti
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Science, Texas A&M UniversityCollege Station, TX, United States
| | | | - Sara D Lawhon
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Science, Texas A&M UniversityCollege Station, TX, United States
| | - Jairo S Nunes
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Science, Texas A&M UniversityCollege Station, TX, United States
| | - Tamara Gull
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Science, Texas A&M UniversityCollege Station, TX, United States
| | - Sangeeta Khare
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Science, Texas A&M UniversityCollege Station, TX, United States
| | - Leslie G Adams
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Science, Texas A&M UniversityCollege Station, TX, United States
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Barbier T, Zúñiga-Ripa A, Moussa S, Plovier H, Sternon JF, Lázaro-Antón L, Conde-Álvarez R, De Bolle X, Iriarte M, Moriyón I, Letesson JJ. Brucella central carbon metabolism: an update. Crit Rev Microbiol 2017; 44:182-211. [PMID: 28604247 DOI: 10.1080/1040841x.2017.1332002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The brucellae are facultative intracellular pathogens causing brucellosis, an important zoonosis. Here, we review the nutritional, genetic, proteomic and transcriptomic studies on Brucella carbon uptake and central metabolism, information that is needed for a better understanding of Brucella virulence. There is no uniform picture across species but the studies suggest primary and/or secondary transporters for unknown carbohydrates, lactate, glycerol phosphate, erythritol, xylose, ribose, glucose and glucose/galactose, and routes for their incorporation to central metabolism, including an erythritol pathway feeding the pentose phosphate cycle. Significantly, all brucellae lack phosphoenolpyruvate synthase and phosphofructokinase genes, which confirms previous evidence on glycolysis absence, but carry all Entner-Doudoroff (ED) pathway and Krebs cycle (and glyoxylate pathway) genes. However, glucose catabolism proceeds through the pentose phosphate cycle in the classical species, and the ED pathway operates in some rodent-associated brucellae, suggesting an ancestral character for this pathway in this group. Gluconeogenesis is functional but does not rely exclusively on classical fructose bisphosphatases. Evidence obtained using infection models is fragmentary but suggests the combined or sequential use of hexoses/pentoses, amino acids and gluconeogenic substrates. We also discuss the role of the phosphotransferase system, stringent reponse, quorum sensing, BvrR/S and sRNAs in metabolism control, an essential aspect of the life style of facultative intracellular parasites.
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Affiliation(s)
- T Barbier
- a Unité de Recherche en Biologie des Microorganismes , Laboratoire d'Immunologie et de Microbiologie, NARILIS, Université de Namur , Namur , Belgium
| | - A Zúñiga-Ripa
- b Instituto de Salud Tropical (ISTUN), Instituto de Investigación Sanitaria de Navarra (IdISNA) and Depto. Microbiología y Parasitología , Universidad de Navarra, Edificio de Investigación , Pamplona , Spain
| | - S Moussa
- a Unité de Recherche en Biologie des Microorganismes , Laboratoire d'Immunologie et de Microbiologie, NARILIS, Université de Namur , Namur , Belgium
| | - H Plovier
- a Unité de Recherche en Biologie des Microorganismes , Laboratoire d'Immunologie et de Microbiologie, NARILIS, Université de Namur , Namur , Belgium
| | - J F Sternon
- a Unité de Recherche en Biologie des Microorganismes , Laboratoire d'Immunologie et de Microbiologie, NARILIS, Université de Namur , Namur , Belgium
| | - L Lázaro-Antón
- b Instituto de Salud Tropical (ISTUN), Instituto de Investigación Sanitaria de Navarra (IdISNA) and Depto. Microbiología y Parasitología , Universidad de Navarra, Edificio de Investigación , Pamplona , Spain
| | - R Conde-Álvarez
- b Instituto de Salud Tropical (ISTUN), Instituto de Investigación Sanitaria de Navarra (IdISNA) and Depto. Microbiología y Parasitología , Universidad de Navarra, Edificio de Investigación , Pamplona , Spain
| | - X De Bolle
- a Unité de Recherche en Biologie des Microorganismes , Laboratoire d'Immunologie et de Microbiologie, NARILIS, Université de Namur , Namur , Belgium
| | - M Iriarte
- b Instituto de Salud Tropical (ISTUN), Instituto de Investigación Sanitaria de Navarra (IdISNA) and Depto. Microbiología y Parasitología , Universidad de Navarra, Edificio de Investigación , Pamplona , Spain
| | - I Moriyón
- b Instituto de Salud Tropical (ISTUN), Instituto de Investigación Sanitaria de Navarra (IdISNA) and Depto. Microbiología y Parasitología , Universidad de Navarra, Edificio de Investigación , Pamplona , Spain
| | - J J Letesson
- b Instituto de Salud Tropical (ISTUN), Instituto de Investigación Sanitaria de Navarra (IdISNA) and Depto. Microbiología y Parasitología , Universidad de Navarra, Edificio de Investigación , Pamplona , Spain
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Mirnejad R, Jazi FM, Mostafaei S, Sedighi M. Molecular investigation of virulence factors of Brucella melitensis and Brucella abortus strains isolated from clinical and non-clinical samples. Microb Pathog 2017; 109:8-14. [PMID: 28506887 DOI: 10.1016/j.micpath.2017.05.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Revised: 05/06/2017] [Accepted: 05/11/2017] [Indexed: 01/18/2023]
Abstract
Brucella is zoonotic pathogen that induces abortion and sterility in domestic mammals and chronic infections in humans called Malta fever. It is a facultative intracellular potential pathogen with high infectivity. The virulence of Brucella is dependent upon its potential virulence factors such as enzymes and cell envelope associated virulence genes. The aim of this study was to investigate the Brucella virulence factors among strains isolated from humans and animals in different parts of Iran. Seventy eight strains of Brucella species isolated from suspected human and animal cases from several provinces of Iran during 2015-2016 and identified by phenotypic and molecular methods. The multiplex-PCR (M-PCR) assay was performed in order to detect the ure, wbkA, omp19, mviN, manA and perA genes by using gene specific primers. Out of 78 isolates of Brucella spp., 57 (73%) and 21 (27%) isolates were detected as B. melitensis and B. abortus, respectively, by molecular method. The relative frequency of virulence genes ure, wbkA, omp19, mviN, manA and perA were 74.4%, 89.7%, 93.6%, 94.9%, 100% and 92.3%, respectively. Our results indicate that the most of Brucella strains isolated from this region possess high percent of virulence factor genes (ure, wbkA, omp19, mviN, manA and perA) in their genome. So, each step of infection can be mediated by a number of virulence factors and each strain may have a unique combination of these factors that affected the rate of bacterial pathogenesis.
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Affiliation(s)
- Reza Mirnejad
- Molecular Biology Research Center, Baqiyatallah University of Medical Sciences, Tehran, IR Iran.
| | - Faramarz Masjedian Jazi
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, IR Iran.
| | - Shayan Mostafaei
- Researcher in the Rheumatology Research Center, Tehran University of Medical Sciences, IR Iran; Department of Biostatistics, School of Medical Sciences, Tarbiat-Modares University, Tehran, IR Iran.
| | - Mansour Sedighi
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, IR Iran.
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Goodwin ZI, Pascual DW. Brucellosis vaccines for livestock. Vet Immunol Immunopathol 2016; 181:51-58. [DOI: 10.1016/j.vetimm.2016.03.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 03/11/2016] [Accepted: 03/14/2016] [Indexed: 01/18/2023]
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Ducrotoy MJ, Conde-Álvarez R, Blasco JM, Moriyón I. A review of the basis of the immunological diagnosis of ruminant brucellosis. Vet Immunol Immunopathol 2016; 171:81-102. [DOI: 10.1016/j.vetimm.2016.02.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 01/07/2016] [Accepted: 02/02/2016] [Indexed: 01/18/2023]
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Goolab S, Roth RL, van Heerden H, Crampton MC. Analyzing the molecular mechanism of lipoprotein localization in Brucella. Front Microbiol 2015; 6:1189. [PMID: 26579096 PMCID: PMC4623201 DOI: 10.3389/fmicb.2015.01189] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 10/12/2015] [Indexed: 01/18/2023] Open
Abstract
Bacterial lipoproteins possess diverse structure and functionality, ranging from bacterial physiology to pathogenic processes. As such many lipoproteins, originating from Brucella are exploited as potential vaccines to countermeasure brucellosis infection in the host. These membrane proteins are translocated from the cytoplasm to the cell membrane where they are anchored peripherally by a multifaceted targeting mechanism. Although much research has focused on the identification and classification of Brucella lipoproteins and their potential use as vaccine candidates for the treatment of Brucellosis, the underlying route for the translocation of these lipoproteins to the outer surface of the Brucella (and other pathogens) outer membrane (OM) remains mostly unknown. This is partly due to the complexity of the organism and evasive tactics used to escape the host immune system, the variation in biological structure and activity of lipoproteins, combined with the complex nature of the translocation machinery. The biosynthetic pathway of Brucella lipoproteins involves a distinct secretion system aiding translocation from the cytoplasm, where they are modified by lipidation, sorted by the lipoprotein localization machinery pathway and thereafter equipped for export to the OM. Surface localized lipoproteins in Brucella may employ a lipoprotein flippase or the β-barrel assembly complex for translocation. This review provides an overview of the characterized Brucella OM proteins that form part of the OM, including a handful of other characterized bacterial lipoproteins and their mechanisms of translocation. Lipoprotein localization pathways in gram negative bacteria will be used as a model to identify gaps in Brucella lipoprotein localization and infer a potential pathway. Of particular interest are the dual topology lipoproteins identified in Escherichia coli and Haemophilus influenza. The localization and topology of these lipoproteins from other gram negative bacteria are well characterized and may be useful to infer a solution to better understand the translocation process in Brucella.
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Affiliation(s)
- Shivani Goolab
- Protein Technologies, Biosciences, Council for Scientific and Industrial ResearchPretoria, South Africa
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of PretoriaPretoria, South Africa
| | - Robyn L. Roth
- Protein Technologies, Biosciences, Council for Scientific and Industrial ResearchPretoria, South Africa
| | - Henriette van Heerden
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of PretoriaPretoria, South Africa
| | - Michael C. Crampton
- Protein Technologies, Biosciences, Council for Scientific and Industrial ResearchPretoria, South Africa
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46
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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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47
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Heavner ME, Qiu WG, Cheng HP. Phylogenetic Co-Occurrence of ExoR, ExoS, and ChvI, Components of the RSI Bacterial Invasion Switch, Suggests a Key Adaptive Mechanism Regulating the Transition between Free-Living and Host-Invading Phases in Rhizobiales. PLoS One 2015; 10:e0135655. [PMID: 26309130 PMCID: PMC4550343 DOI: 10.1371/journal.pone.0135655] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 07/23/2015] [Indexed: 11/18/2022] Open
Abstract
Both bacterial symbionts and pathogens rely on their host-sensing mechanisms to activate the biosynthetic pathways necessary for their invasion into host cells. The Gram-negative bacterium Sinorhizobium meliloti relies on its RSI (ExoR-ExoS-ChvI) Invasion Switch to turn on the production of succinoglycan, an exopolysaccharide required for its host invasion. Recent whole-genome sequencing efforts have uncovered putative components of RSI-like invasion switches in many other symbiotic and pathogenic bacteria. To explore the possibility of the existence of a common invasion switch, we have conducted a phylogenomic survey of orthologous ExoR, ExoS, and ChvI tripartite sets in more than ninety proteobacterial genomes. Our analyses suggest that functional orthologs of the RSI invasion switch co-exist in Rhizobiales, an order characterized by numerous invasive species, but not in the order’s close relatives. Phylogenomic analyses and reconstruction of orthologous sets of the three proteins in Alphaproteobacteria confirm Rhizobiales-specific gene synteny and congruent RSI evolutionary histories. Evolutionary analyses further revealed site-specific substitutions correlated specifically to either animal-bacteria or plant-bacteria associations. Lineage restricted conservation of any one specialized gene is in itself an indication of species adaptation. However, the orthologous phylogenetic co-occurrence of all interacting partners within this single signaling pathway strongly suggests that the development of the RSI switch was a key adaptive mechanism. The RSI invasion switch, originally found in S. meliloti, is a characteristic of the Rhizobiales, and potentially a conserved crucial activation step that may be targeted to control host invasion by pathogenic bacterial species.
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Affiliation(s)
- Mary Ellen Heavner
- Biochemistry Program, The Graduate Center, City University of New York, New York, New York, United States of America
| | - Wei-Gang Qiu
- Biological Sciences Department, Hunter College, City University of New York, New York, New York, United States of America
| | - Hai-Ping Cheng
- Biochemistry Program, The Graduate Center, City University of New York, New York, New York, United States of America
- Biological Sciences Department, Lehman College, City University of New York, Bronx, New York, United States of America
- * E-mail:
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48
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Yu D, Hui Y, Zai X, Xu J, Liang L, Wang B, Yue J, Li S. Comparative genomic analysis of Brucella abortus vaccine strain 104M reveals a set of candidate genes associated with its virulence attenuation. Virulence 2015; 6:745-54. [PMID: 26039674 DOI: 10.1080/21505594.2015.1038015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
The Brucella abortus strain 104M, a spontaneously attenuated strain, has been used as a vaccine strain in humans against brucellosis for 6 decades in China. Despite many studies, the molecular mechanisms that cause the attenuation are still unclear. Here, we determined the whole-genome sequence of 104M and conducted a comprehensive comparative analysis against the whole genome sequences of the virulent strain, A13334, and other reference strains. This analysis revealed a highly similar genome structure between 104M and A13334. The further comparative genomic analysis between 104M and A13334 revealed a set of genes missing in 104M. Some of these genes were identified to be directly or indirectly associated with virulence. Similarly, a set of mutations in the virulence-related genes was also identified, which may be related to virulence alteration. This study provides a set of candidate genes associated with virulence attenuation in B.abortus vaccine strain 104M.
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Affiliation(s)
- Dong Yu
- a Beijing Institute of Biotechnology ; Beijing , PR China
| | - Yiming Hui
- b LanZhou Institute of Biological Products ; Lanzhou , PR China
| | - Xiaodong Zai
- a Beijing Institute of Biotechnology ; Beijing , PR China
| | - Junjie Xu
- a Beijing Institute of Biotechnology ; Beijing , PR China
| | - Long Liang
- a Beijing Institute of Biotechnology ; Beijing , PR China
| | - Bingxiang Wang
- b LanZhou Institute of Biological Products ; Lanzhou , PR China
| | - Junjie Yue
- a Beijing Institute of Biotechnology ; Beijing , PR China
| | - Shanhu Li
- a Beijing Institute of Biotechnology ; Beijing , PR China
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Wiech EM, Cheng HP, Singh SM. Molecular modeling and computational analyses suggests that the Sinorhizobium meliloti periplasmic regulator protein ExoR adopts a superhelical fold and is controlled by a unique mechanism of proteolysis. Protein Sci 2015; 24:319-27. [PMID: 25492513 PMCID: PMC4353358 DOI: 10.1002/pro.2616] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 11/26/2014] [Accepted: 12/01/2014] [Indexed: 12/12/2022]
Abstract
The Sinorhizobium meliloti periplasmic ExoR protein and the ExoS/ChvI two-component system form a regulatory mechanism that directly controls the transformation of free-living to host-invading cells. In the absence of crystal structures, understanding the molecular mechanism of interaction between ExoR and the ExoS sensor, which is believed to drive the key regulatory step in the invasion process, remains a major challenge. In this study, we present a theoretical structural model of the active form of ExoR protein, ExoRm , generated using computational methods. Our model suggests that ExoR possesses a super-helical fold comprising 12 α-helices forming six Sel1-like repeats, including two that were unidentified in previous studies. This fold is highly conducive to mediating protein-protein interactions and this is corroborated by the identification of putative protein binding sites on the surface of the ExoRm protein. Our studies reveal two novel insights: (a) an extended conformation of the third Sel1-like repeat that might be important for ExoR regulatory function and (b) a buried proteolytic site that implies a unique proteolytic mechanism. This study provides new and interesting insights into the structure of S. meliloti ExoR, lays the groundwork for elaborating the molecular mechanism of ExoRm cleavage, ExoRm -ExoS interactions, and studies of ExoR homologs in other bacterial host interactions.
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Affiliation(s)
- Eliza M Wiech
- Department of Biology, The Graduate Center of the City University of New YorkNew York, New York, 10016
- Department of Biology, Brooklyn College, The City University of New YorkBrooklyn, New York, 11210
| | - Hai-Ping Cheng
- Department of Biology, The Graduate Center of the City University of New YorkNew York, New York, 10016
- Biological Sciences Department, Lehman College, The City University of New YorkBronx, New York, 10468
| | - Shaneen M Singh
- Department of Biology, The Graduate Center of the City University of New YorkNew York, New York, 10016
- Department of Biology, Brooklyn College, The City University of New YorkBrooklyn, New York, 11210
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50
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Ortiz-Román L, Riquelme-Neira R, RobertoVidal, Oñate A. Roles of genomic island 3 (GI-3) BAB1_0267 and BAB1_0270 open reading frames (ORFs) in the virulence of Brucella abortus 2308. Vet Microbiol 2014; 172:279-84. [DOI: 10.1016/j.vetmic.2014.05.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 04/29/2014] [Accepted: 05/04/2014] [Indexed: 12/25/2022]
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