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Marchesini MI, Spera JM, Comerci DJ. The 'ins and outs' of Brucella intracellular journey. Curr Opin Microbiol 2024; 78:102427. [PMID: 38309247 DOI: 10.1016/j.mib.2024.102427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 12/27/2023] [Accepted: 01/04/2024] [Indexed: 02/05/2024]
Abstract
Members of the genus Brucella are the causative agents of brucellosis, a worldwide zoonosis affecting wild and domestic animals and humans. These facultative intracellular pathogens cause long-lasting chronic infections by evolving sophisticated strategies to counteract, evade, or subvert host bactericidal mechanisms in order to establish a secure replicative niche necessary for their survival. In this review, we present recent findings on selected Brucella effectors to illustrate how this pathogen modulates host cell signaling pathways to gain control of the vacuole, promote the formation of a safe intracellular replication niche, alter host cell metabolism to its advantage, and exploit various cellular pathways to ensure egress from the infected cell.
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Affiliation(s)
- María I Marchesini
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín (UNSAM)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Escuela de Bio y Nanotecnologías (EByN), Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | - Juan M Spera
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín (UNSAM)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Escuela de Bio y Nanotecnologías (EByN), Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | - Diego J Comerci
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín (UNSAM)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Escuela de Bio y Nanotecnologías (EByN), Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina; Comisión Nacional de Energía Atómica, Grupo Pecuario, Centro Atómico Ezeiza, Buenos Aires, Argentina.
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2
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Riedel R, Commichau FM, Benndorf D, Hertel R, Holzer K, Hoelzle LE, Mardoukhi MSY, Noack LE, Martienssen M. Biodegradation of selected aminophosphonates by the bacterial isolate Ochrobactrum sp. BTU1. Microbiol Res 2024; 280:127600. [PMID: 38211497 DOI: 10.1016/j.micres.2024.127600] [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: 09/04/2023] [Revised: 12/19/2023] [Accepted: 01/02/2024] [Indexed: 01/13/2024]
Abstract
Aminophosphonates, like glyphosate (GS) or metal chelators such as ethylenediaminetetra(methylenephosphonic acid) (EDTMP), are released on a large scale worldwide. Here, we have characterized a bacterial strain capable of degrading synthetic aminophosphonates. The strain was isolated from LC/MS standard solution. Genome sequencing indicated that the strain belongs to the genus Ochrobactrum. Whole-genome classification using pyANI software to compute a pairwise ANI and other metrics between Brucella assemblies and Ochrobactrum contigs revealed that the bacterial strain is designated as Ochrobactrum sp. BTU1. Degradation batch tests with Ochrobactrum sp. BTU1 and the selected aminophosphonates GS, EDTMP, aminomethylphosphonic acid (AMPA), iminodi(methylene-phosphonic) (IDMP) and ethylaminobis(methylenephosphonic) acid (EABMP) showed that the strain can use all phosphonates as sole phosphorus source during phosphorus starvation. The highest growth rate was achieved with AMPA, while EDTMP and GS were least supportive for growth. Proteome analysis revealed that GS degradation is promoted by C-P lyase via the sarcosine pathway, i.e., initial cleavage at the C-P bond. We also identified C-P lyase to be responsible for degradation of EDTMP, EABMP, IDMP and AMPA. However, the identification of the metabolite ethylenediaminetri(methylenephosphonic acid) via LC/MS analysis in the test medium during EDTMP degradation indicates a different initial cleavage step as compared to GS. For EDTMP, it is evident that the initial cleavage occurs at the C-N bond. The detection of different key enzymes at regulated levels, form the bacterial proteoms during EDTMP exposure, further supports this finding. This study illustrates that widely used and structurally more complex aminophosphonates can be degraded by Ochrobactrum sp. BTU1 via the well-known degradation pathways but with different initial cleavage strategy compared to GS.
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Affiliation(s)
- Ramona Riedel
- Chair of Biotechnology of Water Treatment Brandenburg, Institute of Environmental Technology, BTU Cottbus-Senftenberg, Cottbus, Germany.
| | - Fabian M Commichau
- FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, Senftenberg, Germany; FG Molecular Microbiology, Institute for Biology, University of Hohenheim, Stuttgart, Germany
| | - Dirk Benndorf
- Applied Biosciences and Process Engineering, Anhalt University of Applied Sciences, Köthen, Germany; Chair of Bioprocess Engineering, Otto von Guericke University, Magdeburg, Germany; Bioprocess Engineering, Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany
| | - Robert Hertel
- FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, Senftenberg, Germany; Department of Genomic and Applied Microbiology, Institute of Microbiology and Genetics, Georg-August-University of Göttingen, Göttingen, Germany
| | - Katharina Holzer
- Department of Livestock Infectiology and Environmental Hygiene, Institute of Animal Science, University of Hohenheim, Stuttgart, Germany
| | - Ludwig E Hoelzle
- Department of Livestock Infectiology and Environmental Hygiene, Institute of Animal Science, University of Hohenheim, Stuttgart, Germany
| | - Mohammad Saba Yousef Mardoukhi
- Chair of Biotechnology of Water Treatment Brandenburg, Institute of Environmental Technology, BTU Cottbus-Senftenberg, Cottbus, Germany; FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, Senftenberg, Germany; FG Molecular Microbiology, Institute for Biology, University of Hohenheim, Stuttgart, Germany
| | - Laura Emelie Noack
- Chair of Biotechnology of Water Treatment Brandenburg, Institute of Environmental Technology, BTU Cottbus-Senftenberg, Cottbus, Germany
| | - Marion Martienssen
- Chair of Biotechnology of Water Treatment Brandenburg, Institute of Environmental Technology, BTU Cottbus-Senftenberg, Cottbus, Germany
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Yang J, Wang Y, Hou Y, Sun M, Xia T, Wu X. Evasion of host defense by Brucella. CELL INSIGHT 2024; 3:100143. [PMID: 38250017 PMCID: PMC10797155 DOI: 10.1016/j.cellin.2023.100143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 12/11/2023] [Accepted: 12/11/2023] [Indexed: 01/23/2024]
Abstract
Brucella , an adept intracellular pathogen, causes brucellosis, a zoonotic disease leading to significant global impacts on animal welfare and the economy. Regrettably, there is currently no approved and effective vaccine for human use. The ability of Brucella to evade host defenses is essential for establishing chronic infection and ensuring stable intracellular growth. Brucella employs various mechanisms to evade and undermine the innate and adaptive immune responses of the host through modulating the activation of pattern recognition receptors (PRRs), inflammatory responses, or the activation of immune cells like dendritic cells (DCs) to inhibit antigen presentation. Moreover, it regulates multiple cellular processes such as apoptosis, pyroptosis, and autophagy to establish persistent infection within host cells. This review summarizes the recently discovered mechanisms employed by Brucella to subvert host immune responses and research progress on vaccines, with the aim of advancing our understanding of brucellosis and facilitating the development of more effective vaccines and therapeutic approaches against Brucella .
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Affiliation(s)
- Jinke Yang
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730000, China
| | - Yue Wang
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730000, China
| | - Yuanpan Hou
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730000, China
| | - Mengyao Sun
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730000, China
| | - Tian Xia
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730000, China
| | - Xin Wu
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730000, China
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Zheng M, Lin R, Zhu J, Dong Q, Chen J, Jiang P, Zhang H, Liu J, Chen Z. Effector Proteins of Type IV Secretion System: Weapons of Brucella Used to Fight Against Host Immunity. Curr Stem Cell Res Ther 2024; 19:145-153. [PMID: 36809969 DOI: 10.2174/1574888x18666230222124529] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 11/15/2022] [Accepted: 12/29/2022] [Indexed: 02/24/2023]
Abstract
Brucella is an intracellular bacterial pathogen capable of long-term persistence in the host, resulting in chronic infections in livestock and wildlife. The type IV secretion system (T4SS) is an important virulence factor of Brucella and is composed of 12 protein complexes encoded by the VirB operon. T4SS exerts its function through its secreted 15 effector proteins. The effector proteins act on important signaling pathways in host cells, inducing host immune responses and promoting the survival and replication of Brucella in host cells to promote persistent infection. In this article, we describe the intracellular circulation of Brucella-infected cells and survey the role of Brucella VirB T4SS in regulating inflammatory responses and suppressing host immune responses during infection. In addition, the important mechanisms of these 15 effector proteins in resisting the host immune response during Brucella infection are elucidated. For example, VceC and VceA assist in achieving sustained survival of Brucella in host cells by affecting autophagy and apoptosis. BtpB, together with BtpA, controls the activation of dendritic cells during infection, induces inflammatory responses, and controls host immunity. This article reviews the effector proteins secreted by Brucella T4SS and their involvement in immune responses, which can provide a reliable theoretical basis for the subsequent mechanism of hijacking the host cell signaling pathway by bacteria and contribute to the development of better vaccines to effectively treat Brucella bacterial infection.
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Affiliation(s)
- Min Zheng
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, 110866, Shenyang, China
| | - Ruiqi Lin
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, 110866, Shenyang, China
| | - Jinying Zhu
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, 110866, Shenyang, China
| | - Qiao Dong
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, 110866, Shenyang, China
| | - Jingjing Chen
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, 110866, Shenyang, China
| | - Pengfei Jiang
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, 110866, Shenyang, China
| | - Huan Zhang
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, 110866, Shenyang, China
| | - Jinling Liu
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, 110866, Shenyang, China
| | - Zeliang Chen
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, 110866, Shenyang, China
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Lin R, Li A, Li Y, Shen R, Du F, Zheng M, Zhu J, Chen J, Jiang P, Zhang H, Liu J, Chen X, Chen Z. The Brucella Effector Protein BspF Regulates Apoptosis through the Crotonylation of p53. Microorganisms 2023; 11:2322. [PMID: 37764165 PMCID: PMC10534853 DOI: 10.3390/microorganisms11092322] [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: 08/09/2023] [Revised: 09/11/2023] [Accepted: 09/13/2023] [Indexed: 09/29/2023] Open
Abstract
The Brucella type IV secretion system (T4SS) can promote the intracellular survival and reproduction of Brucella. T4SS secretes effector proteins to act on cellular signaling pathways to inhibit the host's innate immune response and cause a chronic, persistent Brucella infection. Brucella can survive in host cells for a long time by inhibiting macrophage apoptosis and avoiding immune recognition. The effector protein, BspF, secreted by T4SS, can regulate host secretory transport and accelerate the intracellular replication of Brucella. BspF has an acetyltransferase domain of the GNAT (GCN5-related N-acetyltransferases) family, and in our previous crotonylation proteomics data, we have found that BspF has crotonyl transferase activity and crotonylation regulation of host cell protein in the proteomics data. Here, we found that BspF attenuates the crotonylation modification of the interacting protein p53, which reduces the p53 expression through the GNAT domain. BspF can inhibit the transcription and protein expression of downstream apoptotic genes, thereby inhibiting host cell apoptosis. Additionally, the Brucella ΔbspF mutant stain promotes apoptosis and reduces the survival rate of Brucella in the cells. In conclusion, we identified that the T4SS effector protein BspF can regulate host cell apoptosis to assist Brucella in its long-term survival by attenuating crotonylation modification of p53 and decreasing p53 expression. Our findings reveal a unique mechanism of elucidating how Brucella regulates host cell apoptosis and promotes its proliferation through the secretion of effector proteins.
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Affiliation(s)
- Ruiqi Lin
- Key Laboratory of Livestock Infectious Disease, Ministry of Education, Shenyang Agricultural University, Shenyang 110866, China; (R.L.); (A.L.); (R.S.); (F.D.); (M.Z.); (J.Z.); (J.C.); (P.J.); (J.L.); (X.C.)
- Key Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, Shenyang 110866, China
| | - Ang Li
- Key Laboratory of Livestock Infectious Disease, Ministry of Education, Shenyang Agricultural University, Shenyang 110866, China; (R.L.); (A.L.); (R.S.); (F.D.); (M.Z.); (J.Z.); (J.C.); (P.J.); (J.L.); (X.C.)
- Key Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, Shenyang 110866, China
| | - Yuzhuo Li
- Key Laboratory of Livestock Infectious Disease, Ministry of Education, Shenyang Agricultural University, Shenyang 110866, China; (R.L.); (A.L.); (R.S.); (F.D.); (M.Z.); (J.Z.); (J.C.); (P.J.); (J.L.); (X.C.)
- Key Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, Shenyang 110866, China
| | - Ruitong Shen
- Key Laboratory of Livestock Infectious Disease, Ministry of Education, Shenyang Agricultural University, Shenyang 110866, China; (R.L.); (A.L.); (R.S.); (F.D.); (M.Z.); (J.Z.); (J.C.); (P.J.); (J.L.); (X.C.)
- Key Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, Shenyang 110866, China
| | - Fangyuan Du
- Key Laboratory of Livestock Infectious Disease, Ministry of Education, Shenyang Agricultural University, Shenyang 110866, China; (R.L.); (A.L.); (R.S.); (F.D.); (M.Z.); (J.Z.); (J.C.); (P.J.); (J.L.); (X.C.)
- Key Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, Shenyang 110866, China
| | - Min Zheng
- Key Laboratory of Livestock Infectious Disease, Ministry of Education, Shenyang Agricultural University, Shenyang 110866, China; (R.L.); (A.L.); (R.S.); (F.D.); (M.Z.); (J.Z.); (J.C.); (P.J.); (J.L.); (X.C.)
- Key Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, Shenyang 110866, China
| | - Jinying Zhu
- Key Laboratory of Livestock Infectious Disease, Ministry of Education, Shenyang Agricultural University, Shenyang 110866, China; (R.L.); (A.L.); (R.S.); (F.D.); (M.Z.); (J.Z.); (J.C.); (P.J.); (J.L.); (X.C.)
- Key Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, Shenyang 110866, China
| | - Jingjing Chen
- Key Laboratory of Livestock Infectious Disease, Ministry of Education, Shenyang Agricultural University, Shenyang 110866, China; (R.L.); (A.L.); (R.S.); (F.D.); (M.Z.); (J.Z.); (J.C.); (P.J.); (J.L.); (X.C.)
- Key Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, Shenyang 110866, China
| | - Pengfei Jiang
- Key Laboratory of Livestock Infectious Disease, Ministry of Education, Shenyang Agricultural University, Shenyang 110866, China; (R.L.); (A.L.); (R.S.); (F.D.); (M.Z.); (J.Z.); (J.C.); (P.J.); (J.L.); (X.C.)
- Key Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, Shenyang 110866, China
| | - Huan Zhang
- Key Laboratory of Livestock Infectious Disease, Ministry of Education, Shenyang Agricultural University, Shenyang 110866, China; (R.L.); (A.L.); (R.S.); (F.D.); (M.Z.); (J.Z.); (J.C.); (P.J.); (J.L.); (X.C.)
- Key Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, Shenyang 110866, China
| | - Jinling Liu
- Key Laboratory of Livestock Infectious Disease, Ministry of Education, Shenyang Agricultural University, Shenyang 110866, China; (R.L.); (A.L.); (R.S.); (F.D.); (M.Z.); (J.Z.); (J.C.); (P.J.); (J.L.); (X.C.)
- Key Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, Shenyang 110866, China
| | - Xiaoyue Chen
- Key Laboratory of Livestock Infectious Disease, Ministry of Education, Shenyang Agricultural University, Shenyang 110866, China; (R.L.); (A.L.); (R.S.); (F.D.); (M.Z.); (J.Z.); (J.C.); (P.J.); (J.L.); (X.C.)
- Key Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, Shenyang 110866, China
| | - Zeliang Chen
- Key Laboratory of Livestock Infectious Disease, Ministry of Education, Shenyang Agricultural University, Shenyang 110866, China; (R.L.); (A.L.); (R.S.); (F.D.); (M.Z.); (J.Z.); (J.C.); (P.J.); (J.L.); (X.C.)
- Key Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, Shenyang 110866, China
- Department of Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou 510275, China
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Gómez LA, Molina RE, Soto RI, Flores MR, Coloma-Rivero RF, Montero DA, Oñate ÁA. Unraveling the Role of the Zinc-Dependent Metalloproteinase/HTH-Xre Toxin/Antitoxin (TA) System of Brucella abortus in the Oxidative Stress Response: Insights into the Stress Response and Virulence. Toxins (Basel) 2023; 15:536. [PMID: 37755962 PMCID: PMC10538038 DOI: 10.3390/toxins15090536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 08/24/2023] [Accepted: 08/28/2023] [Indexed: 09/28/2023] Open
Abstract
Toxin/antitoxin (TA) systems have been scarcely studied in Brucella abortus, the causative agent of brucellosis, which is one of the most prevalent zoonotic diseases worldwide. In this study, the roles of a putative type II TA system composed by a Zinc-dependent metalloproteinase (ZnMP) and a transcriptional regulator HTH-Xre were evaluated. The deletion of the open reading frame (ORF) BAB1_0270, coding for ZnMP, used to produce a mutant strain, allowed us to evaluate the survival and gene expression of B. abortus 2308 under oxidative conditions. Our results showed that the B. abortus mutant strain exhibited a significantly reduced capacity to survive under hydrogen peroxide-induced oxidative stress. Furthermore, this mutant strain showed a decreased expression of genes coding for catalase (katE), alkyl hydroperoxide reductase (ahpC) and transcriptional regulators (oxyR and oxyR-like), as well as genes involved in the general stress response, phyR and rpoE1, when compared to the wild-type strain. These findings suggest that this type II ZnMP/HTH-Xre TA system is required by B. abortus to resist oxidative stress. Additionally, previous evidence has demonstrated that this ZnMP also participates in the acidic stress resistance and virulence of B. abortus 2308. Therefore, we propose a hypothetical regulatory function for this ZnMP/HTH-Xre TA system, providing insight into the stress response and its potential roles in the pathogenesis of B. abortus.
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Affiliation(s)
- Leonardo A Gómez
- Laboratory of Molecular Immunology, Department of Microbiology, Faculty of Biological Sciences, University of Concepción, Concepción 4030000, Chile
| | - Raúl E Molina
- Laboratory of Molecular Immunology, Department of Microbiology, Faculty of Biological Sciences, University of Concepción, Concepción 4030000, Chile
| | - Rodrigo I Soto
- Laboratory of Molecular Immunology, Department of Microbiology, Faculty of Biological Sciences, University of Concepción, Concepción 4030000, Chile
| | - Manuel R Flores
- Laboratory of Molecular Immunology, Department of Microbiology, Faculty of Biological Sciences, University of Concepción, Concepción 4030000, Chile
| | - Roberto F Coloma-Rivero
- Laboratory of Molecular Immunology, Department of Microbiology, Faculty of Biological Sciences, University of Concepción, Concepción 4030000, Chile
| | - David A Montero
- Laboratory of Molecular Immunology, Department of Microbiology, Faculty of Biological Sciences, University of Concepción, Concepción 4030000, Chile
| | - Ángel A Oñate
- Laboratory of Molecular Immunology, Department of Microbiology, Faculty of Biological Sciences, University of Concepción, Concepción 4030000, Chile
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Verbeke J, Fayt Y, Martin L, Yilmaz O, Sedzicki J, Reboul A, Jadot M, Renard P, Dehio C, Renard H, Letesson J, De Bolle X, Arnould T. Host cell egress of Brucella abortus requires BNIP3L-mediated mitophagy. EMBO J 2023; 42:e112817. [PMID: 37232029 PMCID: PMC10350838 DOI: 10.15252/embj.2022112817] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 05/09/2023] [Accepted: 05/11/2023] [Indexed: 05/27/2023] Open
Abstract
The facultative intracellular pathogen Brucella abortus interacts with several organelles of the host cell to reach its replicative niche inside the endoplasmic reticulum. However, little is known about the interplay between the intracellular bacteria and the host cell mitochondria. Here, we showed that B. abortus triggers substantive mitochondrial network fragmentation, accompanied by mitophagy and the formation of mitochondrial Brucella-containing vacuoles during the late steps of cellular infection. Brucella-induced expression of the mitophagy receptor BNIP3L is essential for these events and relies on the iron-dependent stabilisation of the hypoxia-inducible factor 1α. Functionally, BNIP3L-mediated mitophagy appears to be advantageous for bacterial exit from the host cell as BNIP3L depletion drastically reduces the number of reinfection events. Altogether, these findings highlight the intricate link between Brucella trafficking and the mitochondria during host cell infection.
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Affiliation(s)
- Jérémy Verbeke
- Research Unit in Cell Biology (URBC)—Namur Research Institute for Life Sciences (NARILIS)University of NamurNamurBelgium
| | - Youri Fayt
- Research Unit in Cell Biology (URBC)—Namur Research Institute for Life Sciences (NARILIS)University of NamurNamurBelgium
| | - Lisa Martin
- Research Unit in Cell Biology (URBC)—Namur Research Institute for Life Sciences (NARILIS)University of NamurNamurBelgium
| | - Oya Yilmaz
- Research Unit in Cell Biology (URBC)—Namur Research Institute for Life Sciences (NARILIS)University of NamurNamurBelgium
| | | | - Angéline Reboul
- Research Unit in Microorganisms Biology (URBM)—Namur Research Institute for Life Sciences (NARILIS)University of NamurNamurBelgium
| | - Michel Jadot
- Research Unit in Molecular Physiology (URPhyM)—Namur Research Institute for Life Sciences (NARILIS)University of NamurNamurBelgium
| | - Patricia Renard
- Research Unit in Cell Biology (URBC)—Namur Research Institute for Life Sciences (NARILIS)University of NamurNamurBelgium
| | | | - Henri‐François Renard
- Research Unit in Cell Biology (URBC)—Namur Research Institute for Life Sciences (NARILIS)University of NamurNamurBelgium
| | - Jean‐Jacques Letesson
- Research Unit in Microorganisms Biology (URBM)—Namur Research Institute for Life Sciences (NARILIS)University of NamurNamurBelgium
| | - Xavier De Bolle
- Research Unit in Microorganisms Biology (URBM)—Namur Research Institute for Life Sciences (NARILIS)University of NamurNamurBelgium
| | - Thierry Arnould
- Research Unit in Cell Biology (URBC)—Namur Research Institute for Life Sciences (NARILIS)University of NamurNamurBelgium
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Verbeke J, De Bolle X, Arnould T. To eat or not to eat mitochondria? How do host cells cope with mitophagy upon bacterial infection? PLoS Pathog 2023; 19:e1011471. [PMID: 37410705 DOI: 10.1371/journal.ppat.1011471] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/08/2023] Open
Abstract
Mitochondria fulfil a plethora of cellular functions ranging from energy production to regulation of inflammation and cell death control. The fundamental role of mitochondria makes them a target of choice for invading pathogens, with either an intracellular or extracellular lifestyle. Indeed, the modulation of mitochondrial functions by several bacterial pathogens has been shown to be beneficial for bacterial survival inside their host. However, so far, relatively little is known about the importance of mitochondrial recycling and degradation pathways through mitophagy in the outcome (success or failure) of bacterial infection. On the one hand, mitophagy could be considered as a defensive response triggered by the host upon infection to maintain mitochondrial homeostasis. However, on the other hand, the pathogen itself may initiate the host mitophagy to escape from mitochondrial-mediated inflammation or antibacterial oxidative stress. In this review, we will discuss the diversity of various mechanisms of mitophagy in a general context, as well as what is currently known about the different bacterial pathogens that have developed strategies to manipulate the host mitophagy.
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Affiliation(s)
- Jérémy Verbeke
- Research Unit in Cell Biology, Laboratory of Biochemistry and Cell Biology URBC)-Namur Research Institute for Life Sciences (NARILIS), University of Namur, Namur, Belgium
| | - Xavier De Bolle
- Research Unit in Microorganisms Biology (URBM)-Namur Research Institute for Life Sciences (NARILIS), University of Namur, Namur, Belgium
| | - Thierry Arnould
- Research Unit in Cell Biology, Laboratory of Biochemistry and Cell Biology URBC)-Namur Research Institute for Life Sciences (NARILIS), University of Namur, Namur, Belgium
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Guo X, Zeng H, Li M, Xiao Y, Gu G, Song Z, Shuai X, Guo J, Huang Q, Zhou B, Chu Y, Jiao H. The mechanism of chronic intracellular infection with Brucella spp. Front Cell Infect Microbiol 2023; 13:1129172. [PMID: 37143745 PMCID: PMC10151771 DOI: 10.3389/fcimb.2023.1129172] [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: 12/21/2022] [Accepted: 03/31/2023] [Indexed: 05/06/2023] Open
Abstract
Globally, brucellosis is a widespread zoonotic disease. It is prevalent in more than 170 countries and regions. It mostly damages an animal's reproductive system and causes extreme economic losses to the animal husbandry industry. Once inside cells, Brucella resides in a vacuole, designated the BCV, which interacts with components of the endocytic and secretory pathways to ensure bacterial survival. Numerous studies conducted recently have revealed that Brucella's ability to cause a chronic infection depends on how it interacts with the host. This paper describes the immune system, apoptosis, and metabolic control of host cells as part of the mechanism of Brucella survival in host cells. Brucella contributes to both the body's non-specific and specific immunity during chronic infection, and it can aid in its survival by causing the body's immune system to become suppressed. In addition, Brucella regulates apoptosis to avoid being detected by the host immune system. The BvrR/BvrS, VjbR, BlxR, and BPE123 proteins enable Brucella to fine-tune its metabolism while also ensuring its survival and replication and improving its ability to adapt to the intracellular environment.
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Affiliation(s)
- Xiaoyi Guo
- The College of Veterinary Medicine, Southwest University, Chongqing, China
| | - Hui Zeng
- The College of Veterinary Medicine, Southwest University, Chongqing, China
| | - Mengjuan Li
- The College of Veterinary Medicine, Southwest University, Chongqing, China
| | - Yu Xiao
- The College of Veterinary Medicine, Southwest University, Chongqing, China
| | - Guojing Gu
- The College of Veterinary Medicine, Southwest University, Chongqing, China
| | - Zhenhui Song
- The College of Veterinary Medicine, Southwest University, Chongqing, China
| | - Xuehong Shuai
- The College of Veterinary Medicine, Southwest University, Chongqing, China
| | - Jianhua Guo
- The College of Veterinary Medicine, Southwest University, Chongqing, China
| | - Qingzhou Huang
- The College of Veterinary Medicine, Southwest University, Chongqing, China
| | - Bo Zhou
- Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, Jilin, China
- *Correspondence: Bo Zhou, ; Yuefeng Chu, ; Hanwei Jiao,
| | - Yuefeng Chu
- State Key Laboratory of Veterinary Etiological Biology, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
- *Correspondence: Bo Zhou, ; Yuefeng Chu, ; Hanwei Jiao,
| | - Hanwei Jiao
- The College of Veterinary Medicine, Southwest University, Chongqing, China
- The Immunology Research Center, Medical Research Institute, Southwest University, Chongqing, China
- *Correspondence: Bo Zhou, ; Yuefeng Chu, ; Hanwei Jiao,
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10
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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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11
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Villanueva JA, Crooks AL, Nagy TA, Quintana JLJ, Dalebroux ZD, Detweiler CS. Salmonella enterica Infections Are Disrupted by Two Small Molecules That Accumulate within Phagosomes and Differentially Damage Bacterial Inner Membranes. mBio 2022; 13:e0179022. [PMID: 36135367 PMCID: PMC9601186 DOI: 10.1128/mbio.01790-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 09/06/2022] [Indexed: 11/23/2022] Open
Abstract
Gram-negative bacteria have a robust cell envelope that excludes or expels many antimicrobial agents. However, during infection, host soluble innate immune factors permeabilize the bacterial outer membrane. We identified two small molecules that exploit outer membrane damage to access the bacterial cell. In standard microbiological media, neither compound inhibited bacterial growth nor permeabilized bacterial outer membranes. In contrast, at micromolar concentrations, JAV1 and JAV2 enabled the killing of an intracellular human pathogen, Salmonella enterica serovar Typhimurium. S. Typhimurium is a Gram-negative bacterium that resides within phagosomes of cells from the monocyte lineage. Under broth conditions that destabilized the lipopolysaccharide layer, JAV2 permeabilized the bacterial inner membrane and was rapidly bactericidal. In contrast, JAV1 activity was more subtle: JAV1 increased membrane fluidity, altered reduction potential, and required more time than JAV2 to disrupt the inner membrane barrier and kill bacteria. Both compounds interacted with glycerophospholipids from Escherichia coli total lipid extract-based liposomes. JAV1 preferentially interacted with cardiolipin and partially relied on cardiolipin production for activity, whereas JAV2 generally interacted with lipids and had modest affinity for phosphatidylglycerol. In mammalian cells, neither compound significantly altered mitochondrial membrane potential at concentrations that killed S. Typhimurium. Instead, JAV1 and JAV2 became trapped within acidic compartments, including macrophage phagosomes. Both compounds improved survival of S. Typhimurium-infected Galleria mellonella larvae. Together, these data demonstrate that JAV1 and JAV2 disrupt bacterial inner membranes by distinct mechanisms and highlight how small, lipophilic, amine-substituted molecules can exploit host soluble innate immunity to facilitate the killing of intravesicular pathogens. IMPORTANCE Innovative strategies for developing new antimicrobials are needed. Combining our knowledge of host-pathogen interactions and relevant drug characteristics has the potential to reveal new approaches to treating infection. We identified two compounds with antibacterial activity specific to infection and with limited host cell toxicity. These compounds appeared to exploit host innate immunity to access the bacterium and differentially damage the bacterial inner membrane. Further, both compounds accumulated within Salmonella-containing and other acidic vesicles, a process known as lysosomal trapping, which protects the host and harms the pathogen. The compounds also increased host survival in an insect infection model. This work highlights the ability of host innate immunity to enable small molecules to act as antibiotics and demonstrates the feasibility of antimicrobial targeting of the inner membrane. Additionally, this study features the potential use of lysosomal trapping to enhance the activities of compounds against intravesicular pathogens.
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Affiliation(s)
- Joseph A. Villanueva
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Amy L. Crooks
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Toni A. Nagy
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Joaquin L. J. Quintana
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Zachary D. Dalebroux
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Corrella S. Detweiler
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
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12
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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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13
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Zhang L, Yu S, Ning X, Fang H, Li J, Zhi F, Li J, Zhou D, Wang A, Jin Y. A LysR Transcriptional Regulator Manipulates Macrophage Autophagy Flux During Brucella Infection. Front Cell Infect Microbiol 2022; 12:858173. [PMID: 35392609 PMCID: PMC8980476 DOI: 10.3389/fcimb.2022.858173] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 02/24/2022] [Indexed: 11/22/2022] Open
Abstract
Brucella, the intracellular bacteria, have evolved subtle strategies to efficiently survive and replicate in macrophages. However, the virulence effector proteins involved are still unclear. LysR-type transcriptional regulators (lttrs) are the largest regulator family with diverse function in prokaryotes. However, very little is known about the role of LysR regulators in the Brucella spp. Here, a BSS2_II0858 gene, encoded as one of the LysR-type regulators, was studied. We successfully constructed a BSS2_II0858 deletion mutant, Δ0858, and complementation strain CΔ0858 in Brucella suis S2. The cell apoptosis induced by B. suis S2 and its derivatives were detected by flow cytometry. The autophagy was then assessed by immunoblot analysis using the IL3I/II and p62 makers. In addition, the autophagy flux was evaluated by double fluorescent labeling method for autophagy marker protein LC3. Our studies demonstrated that B. suis S2 and its derivatives inhibited the programmed cell death in early stage and promoted apoptosis in the later stage during infection in RAW264.7 cells. The BSS2_II0858 gene was found to play no role during apoptosis according to these results. Compared with the wild-type strain, Δ0858 mutant can stimulate the conversion of LC3-I to LC3-II and markedly inhibited the autophagy flux at early stage leading to obvious autophagosome accumulation. This study explored the function of BSS2_II0858 gene and may provide new insights for understanding the mechanisms involved in the survival of Brucella in macrophages.
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Affiliation(s)
- Lu Zhang
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Siyuan Yu
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Xinnuan Ning
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Hui Fang
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Jie Li
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Feijie Zhi
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Junmei Li
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Dong Zhou
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Aihua Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
- *Correspondence: Yaping Jin, ; Aihua Wang,
| | - Yaping Jin
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling, China
- *Correspondence: Yaping Jin, ; Aihua Wang,
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14
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Petit TJ, Lebreton A. Adaptations of intracellular bacteria to vacuolar or cytosolic niches. Trends Microbiol 2022; 30:736-748. [DOI: 10.1016/j.tim.2022.01.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 01/20/2022] [Accepted: 01/21/2022] [Indexed: 12/28/2022]
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15
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de la Garza-García JA, Ouahrani-Bettache S, Lyonnais S, Ornelas-Eusebio E, Freddi L, Al Dahouk S, Occhialini A, Köhler S. Comparative Genome-Wide Transcriptome Analysis of Brucella suis and Brucella microti Under Acid Stress at pH 4.5: Cold Shock Protein CspA and Dps Are Associated With Acid Resistance of B. microti. Front Microbiol 2021; 12:794535. [PMID: 34966374 PMCID: PMC8710502 DOI: 10.3389/fmicb.2021.794535] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 11/12/2021] [Indexed: 11/13/2022] Open
Abstract
Brucellae are facultative intracellular coccobacilli causing brucellosis, one of the most widespread bacterial zoonosis affecting wildlife animals, livestock and humans. The genus Brucella comprises classical and atypical species, such as Brucella suis and Brucella microti, respectively. The latter is characterized by increased metabolic activity, fast growth rates, and extreme acid resistance at pH 2.5, suggesting an advantage for environmental survival. In addition, B. microti is more acid-tolerant than B. suis at the intermediate pH of 4.5. This acid-resistant phenotype of B. microti may have major implications for fitness in soil, food products and macrophages. Our study focused on the identification and characterization of acid resistance determinants of B. suis and B. microti in Gerhardt's minimal medium at pH 4.5 and 7.0 for 20 min and 2 h by comparative RNA-Seq-based transcriptome analysis, validated by RT-qPCR. Results yielded a common core response in both species with a total of 150 differentially expressed genes, and acidic pH-dependent genes regulated specifically in each species. The identified core response mechanisms comprise proton neutralization or extrusion from the cytosol, participating in maintaining physiological intracellular pH values. Differential expression of 441 genes revealed species-specific mechanisms in B. microti with rapid physiological adaptation to acid stress, anticipating potential damage to cellular components and critical energy conditions. Acid stress-induced genes encoding cold shock protein CspA, pseudogene in B. suis, and stress protein Dps were associated with survival of B. microti at pH 4.5. B. suis response with 284 specifically regulated genes suggested increased acid stress-mediated protein misfolding or damaging, triggering the set-up of repair strategies countering the consequences rather than the origin of acid stress and leading to subsequent loss of viability. In conclusion, our work supports the hypothesis that increased acid stress resistance of B. microti is based on selective pressure for the maintenance of functionality of critical genes, and on specific differential gene expression, resulting in rapid adaptation.
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Affiliation(s)
- Jorge A de la Garza-García
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, University Montpellier, INSERM, Montpellier, France
| | - Safia Ouahrani-Bettache
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, University Montpellier, INSERM, Montpellier, France
| | | | - Erika Ornelas-Eusebio
- Unité des Zoonoses Bactériennes and Unité d'Epidémiologie, Laboratoire de Santé Animale, ANSES, University Paris-Est, Maisons-Alfort, France
| | - Luca Freddi
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, University Montpellier, INSERM, Montpellier, France
| | | | - Alessandra Occhialini
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, University Montpellier, INSERM, Montpellier, France
| | - Stephan Köhler
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS, University Montpellier, INSERM, Montpellier, France
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16
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Sauceda-Becerra R, Barrios-García H, Martínez-Burnes J, Arellano-Reynoso B, Benítez-Guzmán A, Hernández-Castro R, Alva-Pérez J. Brucella melitensis invA gene (BME_RS01060) transcription is promoted under acidic stress conditions. Arch Microbiol 2021; 204:52. [DOI: 10.1007/s00203-021-02664-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 10/08/2021] [Accepted: 10/14/2021] [Indexed: 10/19/2022]
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17
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Xiong X, Li B, Zhou Z, Gu G, Li M, Liu J, Jiao H. The VirB System Plays a Crucial Role in Brucella Intracellular Infection. Int J Mol Sci 2021; 22:ijms222413637. [PMID: 34948430 PMCID: PMC8707931 DOI: 10.3390/ijms222413637] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 12/09/2021] [Accepted: 12/15/2021] [Indexed: 01/18/2023] Open
Abstract
Brucellosis is a highly prevalent zoonotic disease caused by Brucella. Brucella spp. are gram-negative facultative intracellular parasitic bacteria. Its intracellular survival and replication depend on a functional virB system, an operon encoded by VirB1–VirB12. Type IV secretion system (T4SS) encoded by the virB operon is an important virulence factor of Brucella. It can subvert cellular pathway and induce host immune response by secreting effectors, which promotes Brucella replication in host cells and induce persistent infection. Therefore, this paper summarizes the function and significance of the VirB system, focusing on the structure of the VirB system where VirB T4SS mediates biogenesis of the endoplasmic reticulum (ER)-derived replicative Brucella-containing vacuole (rBCV), the effectors of T4SS and the cellular pathways it subverts, which will help better understand the pathogenic mechanism of Brucella and provide new ideas for clinical vaccine research and development.
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Affiliation(s)
- Xue Xiong
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
| | - Bowen Li
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
| | - Zhixiong Zhou
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
| | - Guojing Gu
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
| | - Mengjuan Li
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
| | - Jun Liu
- Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Yujinxiang Street 573, Changchun 130122, China
- Correspondence: (J.L.); (H.J.)
| | - Hanwei Jiao
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
- National Center of Technology Innovation for Pigs, Chongqing 402460, China
- Veterinary Scientific Engineering Research Center, Chongqing 402460, China
- Immunology Research Center, Medical Research Institute, Southwest University, Chongqing 402460, China
- Correspondence: (J.L.); (H.J.)
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18
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Vaughn B, Abu Kwaik Y. Idiosyncratic Biogenesis of Intracellular Pathogens-Containing Vacuoles. Front Cell Infect Microbiol 2021; 11:722433. [PMID: 34858868 PMCID: PMC8632064 DOI: 10.3389/fcimb.2021.722433] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 10/25/2021] [Indexed: 12/12/2022] Open
Abstract
While most bacterial species taken up by macrophages are degraded through processing of the bacteria-containing vacuole through the endosomal-lysosomal degradation pathway, intravacuolar pathogens have evolved to evade degradation through the endosomal-lysosomal pathway. All intra-vacuolar pathogens possess specialized secretion systems (T3SS-T7SS) that inject effector proteins into the host cell cytosol to modulate myriad of host cell processes and remodel their vacuoles into proliferative niches. Although intravacuolar pathogens utilize similar secretion systems to interfere with their vacuole biogenesis, each pathogen has evolved a unique toolbox of protein effectors injected into the host cell to interact with, and modulate, distinct host cell targets. Thus, intravacuolar pathogens have evolved clear idiosyncrasies in their interference with their vacuole biogenesis to generate a unique intravacuolar niche suitable for their own proliferation. While there has been a quantum leap in our knowledge of modulation of phagosome biogenesis by intravacuolar pathogens, the detailed biochemical and cellular processes affected remain to be deciphered. Here we discuss how the intravacuolar bacterial pathogens Salmonella, Chlamydia, Mycobacteria, Legionella, Brucella, Coxiella, and Anaplasma utilize their unique set of effectors injected into the host cell to interfere with endocytic, exocytic, and ER-to-Golgi vesicle traffic. However, Coxiella is the main exception for a bacterial pathogen that proliferates within the hydrolytic lysosomal compartment, but its T4SS is essential for adaptation and proliferation within the lysosomal-like vacuole.
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Affiliation(s)
- Bethany Vaughn
- Department of Microbiology and Immunology, University of Louisville, Louisville, KY, United States
| | - Yousef Abu Kwaik
- Department of Microbiology and Immunology, University of Louisville, Louisville, KY, United States.,Center for Predictive Medicine, College of Medicine, University of Louisville, Louisville, KY, United States
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19
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Borghesan E, Smith EP, Myeni S, Binder K, Knodler LA, Celli J. A Brucella effector modulates the Arf6-Rab8a GTPase cascade to promote intravacuolar replication. EMBO J 2021; 40:e107664. [PMID: 34423453 PMCID: PMC8488576 DOI: 10.15252/embj.2021107664] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 07/26/2021] [Accepted: 07/30/2021] [Indexed: 01/15/2023] Open
Abstract
Remodeling of host cellular membrane transport pathways is a common pathogenic trait of many intracellular microbes that is essential to their intravacuolar life cycle and proliferation. The bacterium Brucella abortus generates a host endoplasmic reticulum‐derived vacuole (rBCV) that supports its intracellular growth, via VirB Type IV secretion system‐mediated delivery of effector proteins, whose functions and mode of action are mostly unknown. Here, we show that the effector BspF specifically promotes Brucella replication within rBCVs by interfering with vesicular transport between the trans‐Golgi network (TGN) and recycling endocytic compartment. BspF targeted the recycling endosome, inhibited retrograde traffic to the TGN, and interacted with the Arf6 GTPase‐activating Protein (GAP) ACAP1 to dysregulate Arf6‐/Rab8a‐dependent transport within the recycling endosome, which resulted in accretion of TGN‐associated vesicles by rBCVs and enhanced bacterial growth. Altogether, these findings provide mechanistic insight into bacterial modulation of membrane transport used to promote their own proliferation within intracellular vacuoles.
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Affiliation(s)
- Elizabeth Borghesan
- Paul G. Allen School for Global Health, Washington State University, Pullman, WA, USA
| | - Erin P Smith
- Paul G. Allen School for Global Health, Washington State University, Pullman, WA, USA
| | - Sebenzile Myeni
- Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Kelsey Binder
- Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Leigh A Knodler
- Paul G. Allen School for Global Health, Washington State University, Pullman, WA, USA
| | - Jean Celli
- Paul G. Allen School for Global Health, Washington State University, Pullman, WA, USA.,Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
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20
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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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21
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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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22
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Turel O, Abdillah FK, Yozgat CY, Uzuner S, Duramaz BB, Dundar TT, Seyithanoglu MH, Yesilbas O, Kutlu NO. A Rare Presentation of Neurobrucellosis in a 6-Year-Old Pediatric Patient with Sagittal Sinus Thrombosis. Neuropediatrics 2021; 52:48-51. [PMID: 33017853 DOI: 10.1055/s-0040-1715482] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Brucellosis is one of the most common zoonosis worldwide. It is still endemic in many regions of the world. A 6-year-old female was admitted to the emergency department (ED) due to a sudden change in consciousness, urinary incontinence, vomiting, and difficulty in walking. Neurological examination demonstrated abducens nerve paralysis, mild-to-moderate motor deficit in hemiparesis in the left arm. Brain magnetic resonance imaging showed a hemorrhagic focus at the right frontal lobe and thrombosis in the superior sagittal sinus of the brain. The diagnosis of neurobrucellosis was confirmed by identifying Brucella spp. in the blood culture on the day 6 of pediatric intensive care unit admission; thus, trimethoprim-sulfamethoxazole and rifampicin, and ceftriaxone were promptly initiated. Despite neuroprotective management and acetazolamide, the patient's neurological problems and high intracranial pressure (ICP) persisted. An external ventricular drainage tube and a Codman ICP monitor were placed to be on the consent vigilance of the patient's neurological condition. The patient's ICP continued to increase despite the current treatment regimen; therefore, a decompressive bitemporal craniectomy was performed. The ICP level of the patient returned to its normal range immediately after the craniectomy. The patient did not have any notable neurologic sequelae at the first-year follow-up. Neurobrucellosis is a rare complication of systemic brucellosis and may present as meningitis, encephalitis, myelitis, radiculitis, and/or neuritis. Herein, we describe a six-year-old girl with brucellosis complicated with cerebral vein thrombosis. This case illustrates the need for close monitoring of patients with unexplained neurological signs or symptoms for brucellosis in endemic areas.
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Affiliation(s)
- Ozden Turel
- Department of Pediatric Infectious Diseases, Bezmialem Vakif University, Istanbul, Turkey
| | | | | | - Selcuk Uzuner
- Department of Pediatric Critical Care Medicine, Bezmialem Vakif University, Istanbul, Turkey
| | - Burcu Bursal Duramaz
- Department of Pediatric Infectious Diseases, Bezmialem Vakif University, Istanbul, Turkey
| | - Tolga Turan Dundar
- Department of Neurosurgery, Bezmialem Vakif University, Istanbul, Turkey
| | | | - Osman Yesilbas
- Department of Pediatric Critical Care Medicine, Bezmialem Vakif University, Istanbul, Turkey
| | - Nurettin Onur Kutlu
- Department of Pediatric Critical Care Medicine, Bezmialem Vakif University, Istanbul, Turkey
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23
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Zhang G, Zhong F, Chen L, Qin P, Li J, Zhi F, Tian L, Zhou D, Lin P, Chen H, Tang K, Liu W, Jin Y, Wang A. Integrated Proteomic and Transcriptomic Analyses Reveal the Roles of Brucella Homolog of BAX Inhibitor 1 in Cell Division and Membrane Homeostasis of Brucella suis S2. Front Microbiol 2021; 12:632095. [PMID: 33584633 PMCID: PMC7876416 DOI: 10.3389/fmicb.2021.632095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Accepted: 01/12/2021] [Indexed: 11/20/2022] Open
Abstract
BAX inhibitor 1 (BI-1) is an evolutionarily conserved transmembrane protein first identified in a screening process for human proteins that suppress BAX-induced apoptosis in yeast cells. Eukaryotic BI-1 is a cytoprotective protein that suppresses cell death induced by multiple stimuli in eukaryotes. Brucella, the causative agent of brucellosis that threatens public health and animal husbandry, contains a conserved gene that encodes BI-1-like protein. To explore the role of the Brucella homolog of BI-1, BrBI, in Brucella suis S2, we constructed the brbI deletion mutant strain and its complemented strain. brbI deletion altered the membrane properties of Brucella suis S2 and decreased its resistance to acidic pH, H2O2, polymyxin B, and lincomycin. Additionally, deleting brbI led to defective growth, cell division, and viability in Brucella suis S2. We then revealed the effect of brbI deletion on the physiological characteristics of Brucella suis S2 via integrated transcriptomic and proteomic analyses. The integrated analysis showed that brbI deletion significantly affected the expression of multiple genes at the mRNA and/or protein levels. Specifically, the affected divisome proteins, FtsB, FtsI, FtsL, and FtsQ, may be the molecular basis of the impaired cell division of the brbI mutant strain, and the extensively affected membrane proteins and transporter-associated proteins were consistent with the phenotype of the membrane properties’ alterations of the brbI mutant strain. In conclusion, our results revealed that BrBI is a bacterial cytoprotective protein involved in membrane homeostasis, cell division, and stress resistance in Brucella suis S2.
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Affiliation(s)
- Guangdong Zhang
- College of Veterinary Medicine, Northwest A&F University, Yangling, China.,Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Fangli Zhong
- College of Veterinary Medicine, Northwest A&F University, Yangling, China.,Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Lei Chen
- College of Veterinary Medicine, Northwest A&F University, Yangling, China.,Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Peipei Qin
- College of Veterinary Medicine, Northwest A&F University, Yangling, China.,Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Junmei Li
- College of Veterinary Medicine, Northwest A&F University, Yangling, China.,Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Feijie Zhi
- College of Veterinary Medicine, Northwest A&F University, Yangling, China.,Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Lulu Tian
- College of Veterinary Medicine, Northwest A&F University, Yangling, China.,Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Dong Zhou
- College of Veterinary Medicine, Northwest A&F University, Yangling, China.,Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Pengfei Lin
- College of Veterinary Medicine, Northwest A&F University, Yangling, China.,Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Huatao Chen
- College of Veterinary Medicine, Northwest A&F University, Yangling, China.,Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Keqiong Tang
- College of Veterinary Medicine, Northwest A&F University, Yangling, China.,Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Wei Liu
- College of Veterinary Medicine, Northwest A&F University, Yangling, China.,Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Yaping Jin
- College of Veterinary Medicine, Northwest A&F University, Yangling, China.,Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Aihua Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling, China.,Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University, Yangling, China
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24
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Ma Z, Li R, Hu R, Deng X, Xu Y, Zheng W, Yi J, Wang Y, Chen C. Brucella abortus BspJ Is a Nucleomodulin That Inhibits Macrophage Apoptosis and Promotes Intracellular Survival of Brucella. Front Microbiol 2020; 11:599205. [PMID: 33281799 PMCID: PMC7688787 DOI: 10.3389/fmicb.2020.599205] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 10/23/2020] [Indexed: 12/11/2022] Open
Abstract
To date, a variety of Brucella effector proteins have been found to mediate host cell secretion, autophagy, inflammation, and other signal pathways, but nuclear effector proteins have not yet been reported. We identified the first Brucella nucleomodulin, BspJ, and we screened out the BspJ interaction host proteins NME/NM23 nucleoside diphosphate kinase 2 (NME2) and creatine kinase B (CKB) through yeast two-hybrid and co-immunoprecipitation assays. These proteins are related to the host cell energy synthesis, metabolism, and apoptosis pathways. Brucella nucleomodulin BspJ will decrease the expression level of NME2 and CKB. In addition, BspJ gene deletion strains promoted the apoptosis of macrophages and reduced the intracellular survival of Brucella in host cells. In short, we found nucleomodulin BspJ may directly or indirectly regulate host cell apoptosis through the interaction with NME2 and CKB by mediating energy metabolism pathways in response to the intracellular circulation of Brucella infection, but the mechanism needs further study.
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Affiliation(s)
- Zhongchen Ma
- International Joint Research Center for Animal Health Breeding, College of Animal Science and Technology, Shihezi University, Shihezi, China
- Collaborative Innovation Center for Prevention and Control of High Incidence Zoonotic Infectious Diseases in Western China, College of Animal Science and Technology, Shihezi University, Shihezi, China
- Key Laboratory of Control and Prevention of Animal Disease, Xinjiang Production & Construction Corps, College of Animal Science and Technology, Shihezi University, Shihezi, China
| | - Ruirui Li
- International Joint Research Center for Animal Health Breeding, College of Animal Science and Technology, Shihezi University, Shihezi, China
- Collaborative Innovation Center for Prevention and Control of High Incidence Zoonotic Infectious Diseases in Western China, College of Animal Science and Technology, Shihezi University, Shihezi, China
- Key Laboratory of Control and Prevention of Animal Disease, Xinjiang Production & Construction Corps, College of Animal Science and Technology, Shihezi University, Shihezi, China
| | - Ruirui Hu
- College of Life Science, Shihezi University, Shihezi, China
| | - Xiaoyu Deng
- International Joint Research Center for Animal Health Breeding, College of Animal Science and Technology, Shihezi University, Shihezi, China
- Collaborative Innovation Center for Prevention and Control of High Incidence Zoonotic Infectious Diseases in Western China, College of Animal Science and Technology, Shihezi University, Shihezi, China
- Key Laboratory of Control and Prevention of Animal Disease, Xinjiang Production & Construction Corps, College of Animal Science and Technology, Shihezi University, Shihezi, China
| | - Yimei Xu
- Xinjiang Center for Disease Control and Prevention, Urumqi, China
| | - Wei Zheng
- International Joint Research Center for Animal Health Breeding, College of Animal Science and Technology, Shihezi University, Shihezi, China
- Collaborative Innovation Center for Prevention and Control of High Incidence Zoonotic Infectious Diseases in Western China, College of Animal Science and Technology, Shihezi University, Shihezi, China
- Key Laboratory of Control and Prevention of Animal Disease, Xinjiang Production & Construction Corps, College of Animal Science and Technology, Shihezi University, Shihezi, China
| | - Jihai Yi
- International Joint Research Center for Animal Health Breeding, College of Animal Science and Technology, Shihezi University, Shihezi, China
- Collaborative Innovation Center for Prevention and Control of High Incidence Zoonotic Infectious Diseases in Western China, College of Animal Science and Technology, Shihezi University, Shihezi, China
- Key Laboratory of Control and Prevention of Animal Disease, Xinjiang Production & Construction Corps, College of Animal Science and Technology, Shihezi University, Shihezi, China
| | - Yong Wang
- International Joint Research Center for Animal Health Breeding, College of Animal Science and Technology, Shihezi University, Shihezi, China
- Collaborative Innovation Center for Prevention and Control of High Incidence Zoonotic Infectious Diseases in Western China, College of Animal Science and Technology, Shihezi University, Shihezi, China
- Key Laboratory of Control and Prevention of Animal Disease, Xinjiang Production & Construction Corps, College of Animal Science and Technology, Shihezi University, Shihezi, China
| | - Chuangfu Chen
- International Joint Research Center for Animal Health Breeding, College of Animal Science and Technology, Shihezi University, Shihezi, China
- Collaborative Innovation Center for Prevention and Control of High Incidence Zoonotic Infectious Diseases in Western China, College of Animal Science and Technology, Shihezi University, Shihezi, China
- Key Laboratory of Control and Prevention of Animal Disease, Xinjiang Production & Construction Corps, College of Animal Science and Technology, Shihezi University, Shihezi, China
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25
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Kornspan D, Zahavi T, Salmon-Divon M. The Acidic Stress Response of the Intracellular Pathogen Brucella melitensis: New Insights from a Comparative, Genome-Wide Transcriptome Analysis. Genes (Basel) 2020; 11:genes11091016. [PMID: 32872264 PMCID: PMC7563570 DOI: 10.3390/genes11091016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/23/2020] [Accepted: 08/25/2020] [Indexed: 11/30/2022] Open
Abstract
The intracellular pathogenic bacteria belonging to the genus Brucella must cope with acidic stress as they penetrate the host via the gastrointestinal route, and again during the initial stages of intracellular infection. A transcription-level regulation has been proposed to explain this but the specific molecular mechanisms are yet to be determined. We recently reported a comparative transcriptomic analysis of the attenuated vaccine Brucella melitensis strain Rev.1 against the virulent strain 16M in cultures grown under either neutral or acidic conditions. Here, we re-analyze the RNA-seq data of 16M from our previous study and compare it to published transcriptomic data of this strain from both an in cellulo and an in vivo model. We identify 588 genes that are exclusively differentially expressed in 16M grown under acidic versus neutral pH conditions, including 286 upregulated genes and 302 downregulated genes that are not differentially expressed in either the in cellulo or the in vivo model. Of these, we highlight 13 key genes that are known to be associated with a bacterial response to acidic stress and, in our study, were highly upregulated under acidic conditions. These genes provide new molecular insights into the mechanisms underlying the acid-resistance of Brucella within its host.
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Affiliation(s)
- David Kornspan
- Department of Bacteriology, Kimron Veterinary Institute, Bet Dagan 50250, Israel
- Correspondence: ; Tel.: +972-3-968-1745
| | - Tamar Zahavi
- Genomic Bioinformatics Laboratory, Department of Molecular Biology, Ariel University, Ariel 40700, Israel; (T.Z.); (M.S.-D.)
| | - Mali Salmon-Divon
- Genomic Bioinformatics Laboratory, Department of Molecular Biology, Ariel University, Ariel 40700, Israel; (T.Z.); (M.S.-D.)
- Adelson School of Medicine, Ariel University, Ariel 40700, Israel
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26
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Cenens W, Andrade MO, Llontop E, Alvarez-Martinez CE, Sgro GG, Farah CS. Bactericidal type IV secretion system homeostasis in Xanthomonas citri. PLoS Pathog 2020; 16:e1008561. [PMID: 32453788 PMCID: PMC7286519 DOI: 10.1371/journal.ppat.1008561] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 06/10/2020] [Accepted: 04/18/2020] [Indexed: 11/19/2022] Open
Abstract
Several Xanthomonas species have a type IV secretion system (T4SS) that injects a cocktail of antibacterial proteins into neighbouring Gram-negative bacteria, often leading to rapid lysis upon cell contact. This capability represents an obvious fitness benefit since it can eliminate competition while the liberated contents of the lysed bacteria could provide an increase in the local availability of nutrients. However, the production of this Mega Dalton-sized molecular machine, with over a hundred subunits, also imposes a significant metabolic cost. Here we show that the chromosomal virB operon, which encodes the structural genes of this T4SS in X. citri, is regulated by the conserved global regulator CsrA. Relieving CsrA repression from the virB operon produced a greater number of T4SSs in the cell envelope and an increased efficiency in contact-dependent lysis of target cells. However, this was also accompanied by a physiological cost leading to reduced fitness when in co-culture with wild-type X. citri. We show that T4SS production is constitutive despite being downregulated by CsrA. Cells subjected to a wide range of rich and poor growth conditions maintain a constant density of T4SSs in the cell envelope and concomitant interbacterial competitiveness. These results show that CsrA provides a constant though partial repression on the virB operon, independent of the tested growth conditions, in this way controlling T4SS-related costs while at the same time maintaining X. citri's aggressive posture when confronted by competitors.
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Affiliation(s)
- William Cenens
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo (USP), Av. Prof. Lineu Prestes 748, São Paulo, SP, Brazil
| | - Maxuel O. Andrade
- Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais, R. Giuseppe Máximo Scolfaro, Campinas, SP, Brazil
| | - Edgar Llontop
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo (USP), Av. Prof. Lineu Prestes 748, São Paulo, SP, Brazil
| | - Cristina E. Alvarez-Martinez
- Departamento de Genética, Evolução, Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Rua Monteiro Lobato, Campinas, SP, Brazil
| | - Germán G. Sgro
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo (USP), Av. Prof. Lineu Prestes 748, São Paulo, SP, Brazil
| | - Chuck S. Farah
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo (USP), Av. Prof. Lineu Prestes 748, São Paulo, SP, Brazil
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27
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Salmon-Divon M, Kornspan D. Transcriptomic analysis of smooth versus rough Brucella melitensis Rev.1 vaccine strains reveals insights into virulence attenuation. Int J Med Microbiol 2019; 310:151363. [PMID: 31699441 DOI: 10.1016/j.ijmm.2019.151363] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 09/10/2019] [Accepted: 10/16/2019] [Indexed: 12/20/2022] Open
Abstract
Brucella melitensis Rev.1 is the live attenuated Elberg-originated vaccine strain of the facultative intracellular Brucella species, and is widely used to control brucellosis in small ruminants. However, Rev.1 may cause abortions in small ruminants that have been vaccinated during the last trimester of gestation, it is pathogenic to humans, and it induces antibodies directed at the O-polysaccharide (O-PS) of the smooth lipopolysaccharide, thus making it difficult to distinguish between vaccinated and infected animals. Rough Brucella strains, which lack O-PS and are considered less pathogenic, have been introduced to address these drawbacks; however, as Rev.1 confers a much better immunity than the rough mutants, it is still considered the reference vaccine for the prophylaxis of brucellosis in small ruminants. Therefore, developing an improved vaccine strain, which lacks the Rev.1 drawbacks, is a highly evaluated task, which requires a better understanding of the molecular mechanisms underlying the virulence attenuation of Rev.1 smooth strains and of natural Rev.1 rough strains, which are currently only partly understood. As the acidification of the Brucella-containing vacuole during the initial stages of infection is crucial for their survival, identifying the genes that contribute to their survival in an acidic environment versus a normal environment will greatly assist our understanding of the molecular pathogenic mechanisms and the attenuated virulence of the Rev.1 strain. Here, we compared the transcriptomes of the smooth and natural rough Rev.1 strains, each grown under either normal or acidic conditions. We found 12 key genes that are significantly downregulated in the Rev.1 rough strains under normal pH, as compared with Rev.1 smooth strains, and six highly important genes that are significantly upregulated in the smooth strains under acidic conditions, as compared with Rev.1 rough strains. All 18 differentially expressed genes are associated with bacterial virulence and survival and may explain the attenuated virulence of the rough Rev.1 strains versus smooth Rev.1 strains, thus providing new insights into the virulence attenuation mechanisms of Brucella. These highly important candidate genes may facilitate the design of new and improved brucellosis vaccines.
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Affiliation(s)
- Mali Salmon-Divon
- Genomic Bioinformatics Laboratory, Department of Molecular Biology, Ariel University, Ariel, Israel; Adelson School of Medicine, Ariel University, Israel.
| | - David Kornspan
- Department of Bacteriology, Kimron Veterinary Institute, Bet Dagan, Israel.
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28
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Deng H, Zhou J, Gong B, Xiao M, Zhang M, Pang Q, Zhang X, Zhao B, Zhou X. Screening and identification of a human domain antibody against Brucella abortus VirB5. Acta Trop 2019; 197:105026. [PMID: 31103700 DOI: 10.1016/j.actatropica.2019.05.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 04/02/2019] [Accepted: 05/15/2019] [Indexed: 01/18/2023]
Abstract
Brucellosis is caused by the genus Brucella. Brucella is widely distributed in cattle, swine, sheep, goat and other mammals including human. Animal brucellosis causes severe economic losses and affects related international transportation and trade. Human brucellosis causes both acute and chronic symptoms of multi-organ dysfunction. Brucella type IV secretion system (T4SS) VirB5 was required for macrophages infection and essential for virulence in mice. VirB5 is located on the cell surface and serves as a specific adhesin targeting host cell receptors. The aim of this study was to isolate and characterize a specific human domain antibody against Brucella abortus (B. abortus) VirB5 from human single domain antibody (sdAb or VHH) phage display library. Following five rounds of screening, an sdAb named as BaV5VH4 showed the highest affinity by enzyme-linked immunosorbent assay (ELISA). Its interaction with B. abortus VirB5 was verified by binding assay, dot blot and molecular docking. These findings in this paper could greatly help elucidate the molecular mechanisms of Brucella infection, and accelerate the development of sdAbs-based vaccines and neutralizing therapeutics of brucellosis.
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29
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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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30
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Patra S, Tellapragada C, Vandana KE, Mukhopadhyay C. Diagnostic utility of in-house loop-mediated isothermal amplification and real-time PCR targeting virB gene for direct detection of Brucella melitensis from clinical specimens. J Appl Microbiol 2019; 127:230-236. [PMID: 30897267 DOI: 10.1111/jam.14260] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 03/12/2019] [Accepted: 03/17/2019] [Indexed: 11/28/2022]
Abstract
AIMS In this present study, the utility of a newly developed loop-mediated isothermal amplification (LAMP) and real-time PCR assays designed to amplify the virB gene region of Brucella melitensis was evaluated from human clinical specimens. METHODS AND RESULTS Fifty-four culture-confirmed cases of brucellosis and 54 culture negative but clinically suspected cases of brucellosis were included in the study. Whole blood, serum and other nonblood specimens were collected and subjected to blood culture using automatic blood culture system, serological tests, LAMP assay and real-time PCR. Overall sensitivities of LAMP and real-time PCR assays were 67·5 and 68·3% respectively. For nonblood clinical specimens, we noticed a marked increase in the sensitivities of LAMP (88·9%) and real-time PCR (100%) assays. CONCLUSIONS Performance of LAMP and real-time PCR was not satisfactory for whole-blood specimens because of the low abundance of bacteria or DNA. On the other hand, using nonblood specimens, both the assays showed higher sensitivity and specificity which makes them a good alternative for the rapid diagnosis of human brucellosis. SIGNIFICANCE AND IMPACT OF THE STUDY The developed LAMP and real-time PCR assays are a specific and rapid diagnostic tool for direct and early detection of Brucella in clinical specimens.
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Affiliation(s)
- S Patra
- Department of Microbiology, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India
| | - C Tellapragada
- Department of Microbiology, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India
| | - K E Vandana
- Department of Microbiology, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India
| | - C Mukhopadhyay
- Department of Microbiology, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India
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A Chemical Genetics Screen Reveals Influence of p38 Mitogen-Activated Protein Kinase and Autophagy on Phagosome Development and Intracellular Replication of Brucella neotomae in Macrophages. Infect Immun 2019; 87:IAI.00044-19. [PMID: 31160361 DOI: 10.1128/iai.00044-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 05/24/2019] [Indexed: 11/20/2022] Open
Abstract
Brucella is an intracellular bacterial pathogen that causes chronic systemic infection in domesticated livestock and poses a zoonotic infectious risk to humans. The virulence of Brucella is critically dependent on its ability to replicate and survive within host macrophages. Brucella modulates host physiological pathways and cell biology in order to establish a productive intracellular replicative niche. Conversely, the host cell presumably activates pathways that limit infection. To identify host pathways contributing to this yin and yang during host cell infection, we performed a high-throughput chemical genetics screen of known inhibitors and agonists of host cell targets to identify host factors that contribute to intracellular growth of the model pathogen Brucella neotomae Using this approach, we identified the p38 mitogen-activated protein (MAP) kinase pathway and autophagy machinery as both a linchpin and an Achilles' heel in B. neotomae's ability to coopt host cell machinery and replicate within macrophages. Specifically, B. neotomae induced p38 MAP kinase phosphorylation and autophagy in a type IV secretion system-dependent fashion. Both p38 MAP kinase stimulation and an intact autophagy machinery in turn were required for phagosome maturation and intracellular replication. These findings contrasted with those for Legionella pneumophila, where chemical inhibition of the p38 MAP kinase pathway and autophagy factor depletion failed to block intracellular replication. Therefore, results from a chemical genetics screen suggest that intersections of the MAP kinase pathways and autophagy machinery are critical components of Brucella's intracellular life cycle.
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A Role for the VPS Retromer in Brucella Intracellular Replication Revealed by Genomewide siRNA Screening. mSphere 2019; 4:4/3/e00380-19. [PMID: 31243080 PMCID: PMC6595151 DOI: 10.1128/msphere.00380-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Brucella, the agent causing brucellosis, is a major zoonotic pathogen with worldwide distribution. Brucella resides and replicates inside infected host cells in membrane-bound compartments called Brucella-containing vacuoles (BCVs). Following uptake, Brucella resides in endosomal BCVs (eBCVs) that gradually mature from early to late endosomal features. Through a poorly understood process that is key to the intracellular lifestyle of Brucella, the eBCV escapes fusion with lysosomes by transitioning to the replicative BCV (rBCV), a replicative niche directly connected to the endoplasmic reticulum (ER). Despite the notion that this complex intracellular lifestyle must depend on a multitude of host factors, a holistic view on which of these components control Brucella cell entry, trafficking, and replication is still missing. Here we used a systematic cell-based small interfering RNA (siRNA) knockdown screen in HeLa cells infected with Brucella abortus and identified 425 components of the human infectome for Brucella infection. These include multiple components of pathways involved in central processes such as the cell cycle, actin cytoskeleton dynamics, or vesicular trafficking. Using assays for pathogen entry, knockdown complementation, and colocalization at single-cell resolution, we identified the requirement of the VPS retromer for Brucella to escape the lysosomal degradative pathway and to establish its intracellular replicative niche. We thus validated the VPS retromer as a novel host factor critical for Brucella intracellular trafficking. Further, our genomewide data shed light on the interplay between central host processes and the biogenesis of the Brucella replicative niche.IMPORTANCE With >300,000 new cases of human brucellosis annually, Brucella is regarded as one of the most important zoonotic bacterial pathogens worldwide. The agent causing brucellosis resides inside host cells within vacuoles termed Brucella-containing vacuoles (BCVs). Although a few host components required to escape the degradative lysosomal pathway and to establish the ER-derived replicative BCV (rBCV) have already been identified, the global understanding of this highly coordinated process is still partial, and many factors remain unknown. To gain deeper insight into these fundamental questions, we performed a genomewide RNA interference (RNAi) screen aiming at discovering novel host factors involved in the Brucella intracellular cycle. We identified 425 host proteins that contribute to Brucella cellular entry, intracellular trafficking, and replication. Together, this study sheds light on previously unknown host pathways required for the Brucella infection cycle and highlights the VPS retromer components as critical factors for the establishment of the Brucella intracellular replicative niche.
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Abstract
In this article, we explore the unique adaptations of intracellular bacterial pathogens that manipulate conserved cellular pathways, organelles, and cargo to convert the phagosome into a pathogen-containing vacuole (PCV). The phagosome is a degradative organelle that rapidly acidifies as it delivers cargo to the lysosome to destroy microbes and cellular debris. However, to avoid this fate, intracellular bacterial pathogens hijack the key molecular modulators of intracellular traffic: small GTPases, phospholipids, SNAREs, and their associated effectors. Following uptake, pathogens that reside in the phagosome either remain associated with the endocytic pathway or rapidly diverge from the preprogrammed route to the lysosome. Both groups rely on effector-mediated mechanisms to meet the common challenges of intracellular life, such as nutrient acquisition, vacuole expansion, and evasion of the host immune response. Mycobacteria, Salmonella, and Coxiella serve as a lens through which we explore regulators of the canonical endocytic route and pathogens that seek to subvert it. On the other hand, pathogens such as Chlamydia, Legionella, and Brucella disconnect from the canonical endocytic route. This bifurcation is linked to extensive hijacking of the secretory pathway and repurposing of the PCV into specialized compartments that resemble organelles in the secretory network. Finally, each pathogen devises specific strategies to counteract host immune responses, such as autophagy, which aim to destroy these aberrant organelles. Collectively, each unique intracellular niche and the pathogens that construct them reflect the outcome of an aggressive and ongoing molecular arms race at the host-pathogen interface. Improving our understanding of these well-adapted pathogens can help us refine our knowledge of conserved cell biological processes.
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Abstract
Bacteria of the genus Brucella colonize a wide variety of mammalian hosts, in which their infectious cycle and ability to cause disease predominantly rely on an intracellular lifestyle within phagocytes. Upon entry into host cells, Brucella organisms undergo a complex, multistage intracellular cycle in which they sequentially traffic through, and exploit functions of, the endocytic, secretory, and autophagic compartments via type IV secretion system (T4SS)-mediated delivery of bacterial effectors. These effectors modulate an array of host functions and machineries to first promote conversion of the initial endosome-like Brucella-containing vacuole (eBCV) into a replication-permissive organelle derived from the host endoplasmic reticulum (rBCV) and then to an autophagy-related vacuole (aBCV) that mediates bacterial egress. Here we detail and discuss our current knowledge of cellular and molecular events of the Brucella intracellular cycle. We discuss the importance of the endosomal stage in determining T4SS competency, the roles of autophagy in rBCV biogenesis and aBCV formation, and T4SS-driven mechanisms of modulation of host secretory traffic in rBCV biogenesis and bacterial egress.
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35
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Salmon-Divon M, Zahavi T, Kornspan D. Transcriptomic Analysis of the Brucella melitensis Rev.1 Vaccine Strain in an Acidic Environment: Insights Into Virulence Attenuation. Front Microbiol 2019; 10:250. [PMID: 30837973 PMCID: PMC6382750 DOI: 10.3389/fmicb.2019.00250] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 01/30/2019] [Indexed: 12/12/2022] Open
Abstract
The live attenuated Brucella melitensis Rev.1 (Elberg-originated) vaccine strain is widely used to control the zoonotic infection brucellosis in small ruminants, but the molecular mechanisms underlying the attenuation of this strain have not been fully characterized. Following their uptake by the host cell, Brucella replicate inside a membrane-bound compartment—the Brucella-containing vacuole—whose acidification is essential for the survival of the pathogen. Therefore, identifying the genes that contribute to the survival of Brucella in acidic environments will greatly assist our understanding of its molecular pathogenic mechanisms and of the attenuated virulence of the Rev.1 strain. Here, we conducted a comprehensive comparative transcriptome analysis of the Rev.1 vaccine strain against the virulent reference strain 16M in cultures grown under either normal or acidic conditions. We found 403 genes that respond differently to acidic conditions in the two strains (FDR < 0.05, fold change ≥ 2). These genes are involved in crucial cellular processes, including metabolic, biosynthetic, and transport processes. Among the highly enriched genes that were downregulated in Rev.1 under acidic conditions were acetyl-CoA synthetase, aldehyde dehydrogenase, cell division proteins, a cold-shock protein, GroEL, and VirB3. The downregulation of these genes may explain the attenuated virulence of Rev.1 and provide new insights into the virulence mechanisms of Brucella.
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Affiliation(s)
- Mali Salmon-Divon
- Genomic Bioinformatics Laboratory, Department of Molecular Biology, Ariel University, Ariel, Israel
| | - Tamar Zahavi
- Genomic Bioinformatics Laboratory, Department of Molecular Biology, Ariel University, Ariel, Israel
| | - David Kornspan
- Department of Bacteriology, Kimron Veterinary Institute, Bet Dagan, Israel
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Visser JG, Van Staden ADP, Smith C. Harnessing Macrophages for Controlled-Release Drug Delivery: Lessons From Microbes. Front Pharmacol 2019; 10:22. [PMID: 30740053 PMCID: PMC6355695 DOI: 10.3389/fphar.2019.00022] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 01/09/2019] [Indexed: 01/15/2023] Open
Abstract
With the effectiveness of therapeutic agents ever decreasing and the increased incidence of multi-drug resistant pathogens, there is a clear need for administration of more potent, potentially more toxic, drugs. Alternatively, biopharmaceuticals may hold potential but require specialized protection from premature in vivo degradation. Thus, a paralleled need for specialized drug delivery systems has arisen. Although cell-mediated drug delivery is not a completely novel concept, the few applications described to date are not yet ready for in vivo application, for various reasons such as drug-induced carrier cell death, limited control over the site and timing of drug release and/or drug degradation by the host immune system. Here, we present our hypothesis for a new drug delivery system, which aims to negate these limitations. We propose transport of nanoparticle-encapsulated drugs inside autologous macrophages polarized to M1 phenotype for high mobility and treated to induce transient phagosome maturation arrest. In addition, we propose a significant shift of existing paradigms in the study of host-microbe interactions, in order to study microbial host immune evasion and dissemination patterns for their therapeutic utilization in the context of drug delivery. We describe a system in which microbial strategies may be adopted to facilitate absolute control over drug delivery, and without sacrificing the host carrier cells. We provide a comprehensive summary of the lessons we can learn from microbes in the context of drug delivery and discuss their feasibility for in vivo therapeutic application. We then describe our proposed "synthetic microbe drug delivery system" in detail. In our opinion, this multidisciplinary approach may hold the solution to effective, controlled drug delivery.
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Affiliation(s)
- Johan Georg Visser
- Department of Physiological Sciences, Stellenbosch University, Matieland, South Africa
| | | | - Carine Smith
- Department of Physiological Sciences, Stellenbosch University, Matieland, South Africa
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Poncin K, Gillet S, De Bolle X. Learning from the master: targets and functions of the CtrA response regulator in Brucella abortus and other alpha-proteobacteria. FEMS Microbiol Rev 2018; 42:500-513. [PMID: 29733367 DOI: 10.1093/femsre/fuy019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 05/02/2018] [Indexed: 12/27/2022] Open
Abstract
The α-proteobacteria are a fascinating group of free-living, symbiotic and pathogenic organisms, including the Brucella genus, which is responsible for a worldwide zoonosis. One common feature of α-proteobacteria is the presence of a conserved response regulator called CtrA, first described in the model bacterium Caulobacter crescentus, where it controls gene expression at different stages of the cell cycle. Here, we focus on Brucella abortus and other intracellular α-proteobacteria in order to better assess the potential role of CtrA in the infectious context. Comparative genomic analyses of the CtrA control pathway revealed the conservation of specific modules, as well as the acquisition of new factors during evolution. The comparison of CtrA regulons also suggests that specific clades of α-proteobacteria acquired distinct functions under its control, depending on the essentiality of the transcription factor. Other CtrA-controlled functions, for instance motility and DNA repair, are proposed to be more ancestral. Altogether, these analyses provide an interesting example of the plasticity of a regulation network, subject to the constraints of inherent imperatives such as cell division and the adaptations to diversified environmental niches.
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Affiliation(s)
- Katy Poncin
- URBM-Biology, Université de Namur, Unité de recherche en biologie moléculaire, Belgium
| | - Sébastien Gillet
- URBM-Biology, Université de Namur, Unité de recherche en biologie moléculaire, Belgium
| | - Xavier De Bolle
- URBM-Biology, Université de Namur, Unité de recherche en biologie moléculaire, Belgium
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38
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Martinez E, Siadous FA, Bonazzi M. Tiny architects: biogenesis of intracellular replicative niches by bacterial pathogens. FEMS Microbiol Rev 2018; 42:425-447. [PMID: 29596635 DOI: 10.1093/femsre/fuy013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 03/26/2018] [Indexed: 11/13/2022] Open
Abstract
Co-evolution of bacterial pathogens with their hosts led to the emergence of a stunning variety of strategies aiming at the evasion of host defences, colonisation of host cells and tissues and, ultimately, the establishment of a successful infection. Pathogenic bacteria are typically classified as extracellular and intracellular; however, intracellular lifestyle comes in many different flavours: some microbes rapidly escape to the cytosol whereas other microbes remain within vacuolar compartments and harness membrane trafficking pathways to generate their host-derived, pathogen-specific replicative niche. Here we review the current knowledge on a variety of vacuolar lifestyles, the effector proteins used by bacteria as tools to take control of the host cell and the main membrane trafficking signalling pathways targeted by vacuolar pathogens as source of membranes and nutrients. Finally, we will also discuss how host cells have developed countermeasures to sense the biogenesis of the aberrant organelles harbouring bacteria. Understanding the dialogue between bacterial and eukaryotic proteins is the key to unravel the molecular mechanisms of infection and in turn, this may lead to the identification of new targets for the development of new antimicrobials.
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Affiliation(s)
- Eric Martinez
- IRIM, University of Montpellier, CNRS, 34293 Montpellier, France
| | | | - Matteo Bonazzi
- IRIM, University of Montpellier, CNRS, 34293 Montpellier, France
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39
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Hisham Y, Ashhab Y. Identification of Cross-Protective Potential Antigens against Pathogenic Brucella spp. through Combining Pan-Genome Analysis with Reverse Vaccinology. J Immunol Res 2018; 2018:1474517. [PMID: 30622973 PMCID: PMC6304850 DOI: 10.1155/2018/1474517] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Accepted: 11/04/2018] [Indexed: 01/18/2023] Open
Abstract
Brucellosis is a zoonotic infectious disease caused by bacteria of the genus Brucella. Brucella melitensis, Brucella abortus, and Brucella suis are the most pathogenic species of this genus causing the majority of human and domestic animal brucellosis. There is a need to develop a safe and potent subunit vaccine to overcome the serious drawbacks of the live attenuated Brucella vaccines. The aim of this work was to discover antigen candidates conserved among the three pathogenic species. In this study, we employed a reverse vaccinology strategy to compute the core proteome of 90 completed genomes: 55 B. melitensis, 17 B. abortus, and 18 B. suis. The core proteome was analyzed by a metasubcellular localization prediction pipeline to identify surface-associated proteins. The identified proteins were thoroughly analyzed using various in silico tools to obtain the most potential protective antigens. The number of core proteins obtained from analyzing the 90 proteomes was 1939 proteins. The surface-associated proteins were 177. The number of potential antigens was 87; those with adhesion score ≥ 0.5 were considered antigen with "high potential," while those with a score of 0.4-0.5 were considered antigens with "intermediate potential." According to a cumulative score derived from protein antigenicity, density of MHC-I and MHC-II epitopes, MHC allele coverage, and B-cell epitope density scores, a final list of 34 potential antigens was obtained. Remarkably, most of the 34 proteins are associated with bacterial adhesion, invasion, evasion, and adaptation to the hostile intracellular environment of macrophages which is adjusted to deprive Brucella of required nutrients. Our results provide a manageable list of potential protective antigens for developing a potent vaccine against brucellosis. Moreover, our elaborated analysis can provide further insights into novel Brucella virulence factors. Our next step is to test some of these antigens using an appropriate antigen delivery system.
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Affiliation(s)
- Yasmin Hisham
- Palestine-Korea Biotechnology Center, Palestine Polytechnic University, Hebron, State of Palestine
| | - Yaqoub Ashhab
- Palestine-Korea Biotechnology Center, Palestine Polytechnic University, Hebron, State of Palestine
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40
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Fernández I, Sycz G, Goldbaum FA, Carrica MDC. Acidic pH triggers the phosphorylation of the response regulator NtrX in alphaproteobacteria. PLoS One 2018; 13:e0194486. [PMID: 29634773 PMCID: PMC5892882 DOI: 10.1371/journal.pone.0194486] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 03/05/2018] [Indexed: 11/19/2022] Open
Abstract
Many signaling pathways that control cellular development, cell-cycle progression and nutritional versatility have been studied in Caulobacter crescentus. For example, it was suggested that the response regulator NtrX is conditionally essential for this bacterium and that it might be necessary for responding to a signal produced in phosphate-replete minimal medium. However, such signal has not been identified yet and the role of NtrX in C. crescentus biology remains elusive. Here, using wild-type C. crescentus and a strain with a chromosomally myc-tagged ntrX gene, we demonstrate that high concentrations of phosphate (10 mM) regulate ntrX transcription and the abundance of the protein. We also show that the pH of the medium acts as a switch able to regulate the phosphorylation status of NtrX, promoting its phosphorylation under mildly acidic conditions and its dephosphorylation at neutral pH. Moreover, we demonstrate that the ntrX gene is required for survival in environments with low pH and under acidic stress. Finally, we prove that NtrX phosphorylation is also triggered by low pH in Brucella abortus, a pathogenic alphaproteobacterium. Overall, our work contributes to deepen the general knowledge of this system and provides tools to elucidate the NtrX regulon.
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Affiliation(s)
- Ignacio Fernández
- Fundación Instituto Leloir, IIBBA-CONICET, Patricias Argentinas, Buenos Aires, Argentina
| | - Gabriela Sycz
- Fundación Instituto Leloir, IIBBA-CONICET, Patricias Argentinas, Buenos Aires, Argentina
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41
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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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Sedzicki J, Tschon T, Low SH, Willemart K, Goldie KN, Letesson JJ, Stahlberg H, Dehio C. 3D correlative electron microscopy reveals continuity of Brucella-containing vacuoles with the endoplasmic reticulum. J Cell Sci 2018; 131:jcs.210799. [PMID: 29361547 DOI: 10.1242/jcs.210799] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 01/04/2018] [Indexed: 01/17/2023] Open
Abstract
Entry of the facultative intracellular pathogen Brucella into host cells results in the formation of endosomal Brucella-containing vacuoles (eBCVs) that initially traffic along the endocytic pathway. eBCV acidification triggers the expression of a type IV secretion system that translocates bacterial effector proteins into host cells. This interferes with lysosomal fusion of eBCVs and supports their maturation to replicative Brucella-containing vacuoles (rBCVs). Bacteria replicate in rBCVs to large numbers, eventually occupying most of the cytoplasmic volume. As rBCV membranes tightly wrap each individual bacterium, they are constantly being expanded and remodeled during exponential bacterial growth. rBCVs are known to carry endoplasmic reticulum (ER) markers; however, the relationship of the vacuole to the genuine ER has remained elusive. Here, we have reconstructed the 3-dimensional ultrastructure of rBCVs and associated ER by correlative structured illumination microscopy (SIM) and focused ion beam/scanning electron microscopic tomography (FIB/SEM). Studying B. abortus-infected HeLa cells and trophoblasts derived from B. melitensis-infected mice, we demonstrate that rBCVs are complex and interconnected compartments that are continuous with neighboring ER cisternae, thus supporting a model that rBCVs are extensions of genuine ER.
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Affiliation(s)
- Jaroslaw Sedzicki
- Focal Area Infection Biology, Biozentrum, University of Basel, 4056 Basel, Switzerland.,Center for Cellular Imaging and NanoAnalytics (C-CINA), Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Therese Tschon
- Focal Area Infection Biology, Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Shyan Huey Low
- Focal Area Infection Biology, Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Kevin Willemart
- Microorganisms Biology Research Unit (URBM, Unité de Recherche en Biologie des Microorganismes), University of Namur, 5000 Namur, Belgium
| | - Kenneth N Goldie
- Center for Cellular Imaging and NanoAnalytics (C-CINA), Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Jean-Jacques Letesson
- Microorganisms Biology Research Unit (URBM, Unité de Recherche en Biologie des Microorganismes), University of Namur, 5000 Namur, Belgium
| | - Henning Stahlberg
- Center for Cellular Imaging and NanoAnalytics (C-CINA), Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Christoph Dehio
- Focal Area Infection Biology, Biozentrum, University of Basel, 4056 Basel, Switzerland
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43
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Weber MM, Faris R. Subversion of the Endocytic and Secretory Pathways by Bacterial Effector Proteins. Front Cell Dev Biol 2018; 6:1. [PMID: 29417046 PMCID: PMC5787570 DOI: 10.3389/fcell.2018.00001] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Accepted: 01/09/2018] [Indexed: 12/22/2022] Open
Abstract
Intracellular bacteria have developed numerous strategies to hijack host vesicular trafficking pathways to form their unique replicative niches. To promote intracellular replication, the bacteria must interact with host organelles and modulate host signaling pathways to acquire nutrients and membrane for the growing parasitophorous vacuole all while suppressing activation of the immune response. To facilitate host cell subversion, bacterial pathogens use specialized secretion systems to deliver bacterial virulence factors, termed effectors, into the host cell that mimic, agonize, and/or antagonize the function of host proteins. In this review we will discuss how bacterial effector proteins from Coxiella burnetii, Brucella abortus, Salmonella enterica serovar Typhimurium, Legionella pneumophila, Chlamydia trachomatis, and Orientia tsutsugamushi manipulate the endocytic and secretory pathways. Understanding how bacterial effector proteins manipulate host processes not only gives us keen insight into bacterial pathogenesis, but also enhances our understanding of how eukaryotic membrane trafficking is regulated.
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Affiliation(s)
- Mary M Weber
- Department of Microbiology and Immunology, University of Iowa, Iowa City, IA, United States
| | - Robert Faris
- Department of Microbiology and Immunology, University of Iowa, Iowa City, IA, United States
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Li P, Tian M, Bao Y, Hu H, Liu J, Yin Y, Ding C, Wang S, Yu S. Brucella Rough Mutant Induce Macrophage Death via Activating IRE1α Pathway of Endoplasmic Reticulum Stress by Enhanced T4SS Secretion. Front Cell Infect Microbiol 2017; 7:422. [PMID: 29021973 PMCID: PMC5623715 DOI: 10.3389/fcimb.2017.00422] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 09/14/2017] [Indexed: 11/21/2022] Open
Abstract
Brucella is a Gram-negative facultative intracellular pathogen that causes the worldwide zoonosis, known as brucellosis. Brucella virulence relies mostly on its ability to invade and replicate within phagocytic cells. The type IV secretion system (T4SS) and lipopolysaccharide are two major Brucella virulence factors. Brucella rough mutants reportedly induce the death of infected macrophages, which is T4SS dependent. However, the underlying molecular mechanism remains unclear. In this study, the T4SS secretion capacities of Brucella rough mutant and its smooth wild-type strain were comparatively investigated, by constructing the firefly luciferase fused T4SS effector, BPE123 and VceC. In addition, quantitative real-time PCR and western blotting were used to analyze the T4SS expression. The results showed that T4SS expression and secretion were enhanced significantly in the Brucella rough mutant. We also found that the activity of the T4SS virB operon promoter was notably increased in the Brucella rough mutant, which depends on quorum sensing-related regulators of VjbR upregulation. Cell infection and cell death assays revealed that deletion of vjbR in the Brucella rough mutant absolutely abolished cytotoxicity within macrophages by downregulating T4SS expression. This suggests that up-regulation of T4SS promoted by VjbR in rough mutant ΔrfbE contribute to macrophage death. In addition, we found that the Brucella rough mutant induce macrophage death via activating IRE1α pathway of endoplasmic reticulum stress. Taken together, our study provide evidence that in comparison to the Brucella smooth wild-type strain, VjbR upregulation in the Brucella rough mutant increases transcription of the virB operon, resulting in overexpression of the T4SS gene, accompanied by the over-secretion of effecter proteins, thereby causing the death of infected macrophages via activating IRE1α pathway of endoplasmic reticulum stress, suggesting novel insights into the molecular mechanisms associated with Brucella rough mutant-induced macrophage cytotoxicity.
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Affiliation(s)
- Peng Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Mingxing Tian
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Yanqing Bao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Hai Hu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Jiameng Liu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Yi Yin
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Chan Ding
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Shaohui Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Shengqing Yu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonosis, Yangzhou, China
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Multivalent Fusion DNA Vaccine against Brucella abortus. BIOMED RESEARCH INTERNATIONAL 2017; 2017:6535479. [PMID: 29082252 PMCID: PMC5610864 DOI: 10.1155/2017/6535479] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 07/05/2017] [Accepted: 08/06/2017] [Indexed: 12/22/2022]
Abstract
As an alternative brucellosis prevention method, we evaluated the immunogenicity induced by new multivalent DNA vaccines in BALB/c mice. We constructed the vaccines by fusion of BAB1_0273 and/or BAB1_0278 open reading frames (ORFs) from genomic island 3 (GI-3) and the Brucella abortus 2308 sodC gene with a link based on prolines and alanines (pV273-sod, pV278-sod, and pV273-278-sod, resp.). Results show that immunization with all tested multivalent DNA vaccines induced a specific humoral and cellular immune response. These novel multivalent vaccines significantly increased the production of IgM, IgG, and IgG2a antibodies as well as IFN-γ levels and the lymphoproliferative response of splenocytes. Although immunization with these multivalent vaccines induced a typical T-helper 1- (Th1-) dominated immune response, such immunogenicity conferred low protection levels in mice challenged with the B. abortus 2308 pathogenic strain. Our results demonstrated that the expression of BAB1_0273 and/or BABl_0278 antigens conjugated to SOD protein can polarize mice immunity to a Th1-type phenotype, conferring low levels of protection.
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Takenouchi T, Kitani H, Suzuki S, Nakai M, Fuchimoto DI, Tsukimoto M, Shinkai H, Sato M, Uenishi H. Immortalization and Characterization of Porcine Macrophages That Had Been Transduced with Lentiviral Vectors Encoding the SV40 Large T Antigen and Porcine Telomerase Reverse Transcriptase. Front Vet Sci 2017; 4:132. [PMID: 28871285 PMCID: PMC5566601 DOI: 10.3389/fvets.2017.00132] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 08/03/2017] [Indexed: 12/14/2022] Open
Abstract
The domestic pig is an important agricultural animal, and thus, infectious diseases that affect pigs can cause severe economic losses in the global swine industry. Various porcine pathogens target macrophages, which are classical innate immune cells. Although macrophages basically protect the host from pathogens, they also seem to contribute to infectious processes. Therefore, cultured macrophages can be used to develop in vitro models for studying not only genes associated with porcine innate immunity but also the infectious processes of porcine pathogens. However, the availability of porcine macrophage cell lines is limited. In this study, we describe a novel immortalized porcine kidney-derived macrophage (IPKM) cell line, which was generated by transferring the SV40 large T antigen (SV40LT) and porcine telomerase reverse transcriptase (pTERT) genes into primary porcine kidney-derived macrophages using lentiviral vectors. The IPKM displayed a typical macrophage morphology and was routinely passaged (doubling time: about 4 days). These cells were immunostained for macrophage markers. In addition, they exhibited substantial phagocytosis of polystyrene microbeads and released inflammatory cytokines upon lipopolysaccharide (LPS) stimulation. Furthermore, the maturation and secretion of interleukin-1β were observed after nigericin-induced inflammasome activation in LPS-primed IPKM. These findings suggest that IPKM exhibit the typical inflammatory characteristics of macrophages. By transferring the SV40LT and pTERT genes using lentiviral vectors, we also successfully immortalized macrophages derived from the peripheral blood of a low-density lipoprotein receptor-deficient pig. These results suggest that the co-expression of SV40LT and pTERT is an effective way of immortalizing porcine macrophages.
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Affiliation(s)
- Takato Takenouchi
- Division of Animal Sciences, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Hiroshi Kitani
- Division of Animal Sciences, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Shunichi Suzuki
- Division of Animal Sciences, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Michiko Nakai
- Division of Animal Sciences, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Dai-Ichiro Fuchimoto
- Division of Animal Sciences, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, Japan
| | | | - Hiroki Shinkai
- Division of Animal Sciences, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Mitsuru Sato
- Division of Animal Sciences, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Hirohide Uenishi
- Division of Animal Sciences, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, Japan
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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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Kleinman CL, Sycz G, Bonomi HR, Rodríguez RM, Zorreguieta A, Sieira R. ChIP-seq analysis of the LuxR-type regulator VjbR reveals novel insights into the Brucella virulence gene expression network. Nucleic Acids Res 2017; 45:5757-5769. [PMID: 28334833 PMCID: PMC5449634 DOI: 10.1093/nar/gkx165] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Revised: 02/27/2017] [Accepted: 03/01/2017] [Indexed: 01/31/2023] Open
Abstract
LuxR-type transcription factors control diverse physiological functions necessary for bacterial adaptation to environmental changes. In the intracellular pathogen Brucella, the LuxR homolog VjbR has been shown to regulate the expression of virulence factors acting at early stages of the intracellular infection and, directly or indirectly, hundreds of additional genes. However, the precise determination of VjbR direct targets has so far proved elusive. Here, we performed chromatin immunoprecipitation of VjbR followed by next-generation sequencing (ChIP-seq). We detected a large amount of VjbR-binding sites distributed across the Brucella genome and determined a markedly asymmetric binding consensus motif, an unusual feature among LuxR-type regulators. RNA-seq analysis performed under conditions mimicking the eukaryotic intracellular environment revealed that, among all loci associated to VjbR-binding, this regulator directly modulated the expression of only a subset of genes encoding functions consistent with an intracellular adaptation strategy for survival during the initial stages of the host cell infection. Other VjbR-binding events, however, showed to be dissociated from transcription and may require different environmental signals to produce a transcriptional output. Taken together, our results bring new insights into the extent and functionality of LuxR-type-related transcriptional networks.
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Affiliation(s)
| | - Gabriela Sycz
- Fundación Instituto Leloir, Ciudad de Buenos Aires C1405BWE, Argentina
| | - Hernán R. Bonomi
- Fundación Instituto Leloir, Ciudad de Buenos Aires C1405BWE, Argentina
| | | | | | - Rodrigo Sieira
- Fundación Instituto Leloir, Ciudad de Buenos Aires C1405BWE, Argentina
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Abdou E, Jiménez de Bagüés MP, Martínez-Abadía I, Ouahrani-Bettache S, Pantesco V, Occhialini A, Al Dahouk S, Köhler S, Jubier-Maurin V. RegA Plays a Key Role in Oxygen-Dependent Establishment of Persistence and in Isocitrate Lyase Activity, a Critical Determinant of In vivo Brucella suis Pathogenicity. Front Cell Infect Microbiol 2017; 7:186. [PMID: 28573107 PMCID: PMC5435760 DOI: 10.3389/fcimb.2017.00186] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 04/28/2017] [Indexed: 12/25/2022] Open
Abstract
For aerobic human pathogens, adaptation to hypoxia is a critical factor for the establishment of persistent infections, as oxygen availability is low inside the host. The two-component system RegB/A of Brucella suis plays a central role in the control of respiratory systems adapted to oxygen deficiency, and in persistence in vivo. Using an original "in vitro model of persistence" consisting in gradual oxygen depletion, we compared transcriptomes and proteomes of wild-type and ΔregA strains to identify the RegA-regulon potentially involved in the set-up of persistence. Consecutive to oxygen consumption resulting in growth arrest, 12% of the genes in B. suis were potentially controlled directly or indirectly by RegA, among which numerous transcriptional regulators were up-regulated. In contrast, genes or proteins involved in envelope biogenesis and in cellular division were repressed, suggesting a possible role for RegA in the set-up of a non-proliferative persistence state. Importantly, the greatest number of the RegA-repressed genes and proteins, including aceA encoding the functional IsoCitrate Lyase (ICL), were involved in energy production. A potential consequence of this RegA impact may be the slowing-down of the central metabolism as B. suis progressively enters into persistence. Moreover, ICL is an essential determinant of pathogenesis and long-term interactions with the host, as demonstrated by the strict dependence of B. suis on ICL activity for multiplication and persistence during in vivo infection. RegA regulates gene or protein expression of all functional groups, which is why RegA is a key regulator of B. suis in adaptation to oxygen depletion. This function may contribute to the constraint of bacterial growth, typical of chronic infection. Oxygen-dependent activation of two-component systems that control persistence regulons, shared by several aerobic human pathogens, has not been studied in Brucella sp. before. This work therefore contributes significantly to the unraveling of persistence mechanisms in this important zoonotic pathogen.
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Affiliation(s)
- Elias Abdou
- Institut de Recherche en Infectiologie de Montpellier UMR9004, Centre National de la Recherche Scientifique, Université de MontpellierMontpellier, France
| | - María P. Jiménez de Bagüés
- Unidad de Tecnología en Producción y Sanidad Animal, Centro de Investigación y Tecnología Agroalimentaria, Instituto Agroalimentario de Aragón (CITA-Universidad de Zaragoza)Zaragoza, Spain
| | - Ignacio Martínez-Abadía
- Institut de Recherche en Infectiologie de Montpellier UMR9004, Centre National de la Recherche Scientifique, Université de MontpellierMontpellier, France
| | - Safia Ouahrani-Bettache
- Institut de Recherche en Infectiologie de Montpellier UMR9004, Centre National de la Recherche Scientifique, Université de MontpellierMontpellier, France
| | - Véronique Pantesco
- Institut de Médecine Régénératrice et Biothérapie—U1183 Institut National de la Santé et de la Recherche MédicaleMontpellier, France
| | - Alessandra Occhialini
- Institut de Recherche en Infectiologie de Montpellier UMR9004, Centre National de la Recherche Scientifique, Université de MontpellierMontpellier, France
| | - Sascha Al Dahouk
- Department of Biological Safety, German Federal Institute for Risk AssessmentBerlin, Germany
| | - Stephan Köhler
- Institut de Recherche en Infectiologie de Montpellier UMR9004, Centre National de la Recherche Scientifique, Université de MontpellierMontpellier, France
| | - Véronique Jubier-Maurin
- Institut de Recherche en Infectiologie de Montpellier UMR9004, Centre National de la Recherche Scientifique, Université de MontpellierMontpellier, France
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Promotion and Rescue of Intracellular Brucella neotomae Replication during Coinfection with Legionella pneumophila. Infect Immun 2017; 85:IAI.00991-16. [PMID: 28264909 DOI: 10.1128/iai.00991-16] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 02/28/2017] [Indexed: 12/17/2022] Open
Abstract
We established a new Brucella neotomaein vitro model system for study of type IV secretion system-dependent (T4SS) pathogenesis in the Brucella genus. Importantly, B. neotomae is a rodent pathogen, and unlike B. abortus, B. melitensis, and B. suis, B. neotomae has not been observed to infect humans. It therefore can be handled more facilely using biosafety level 2 practices. More particularly, using a series of novel fluorescent protein and lux operon reporter systems to differentially label pathogens and track intracellular replication, we confirmed T4SS-dependent intracellular growth of B. neotomae in macrophage cell lines. Furthermore, B. neotomae exhibited early endosomal (LAMP-1) and late endoplasmic reticulum (calreticulin)-associated phagosome maturation. These findings recapitulate prior observations for human-pathogenic Brucella spp. In addition, during coinfection experiments with Legionella pneumophila, we found that defective intracellular replication of a B. neotomae T4SS virB4 mutant was rescued and baseline levels of intracellular replication of wild-type B. neotomae were significantly stimulated by coinfection with wild-type but not T4SS mutant L. pneumophila Using confocal microscopy, it was determined that intracellular colocalization of B. neotomae and L. pneumophila was required for rescue and that colocalization came at a cost to L. pneumophila fitness. These findings were not completely expected based on known temporal and qualitative differences in the intracellular life cycles of these two pathogens. Taken together, we have developed a new system for studying in vitroBrucella pathogenesis and found a remarkable T4SS-dependent interplay between Brucella and Legionella during macrophage coinfection.
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