1
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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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Yu H, Gu X, Wang D, Wang Z. Brucella infection and Toll-like receptors. Front Cell Infect Microbiol 2024; 14:1342684. [PMID: 38533384 PMCID: PMC10963510 DOI: 10.3389/fcimb.2024.1342684] [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: 11/22/2023] [Accepted: 01/17/2024] [Indexed: 03/28/2024] Open
Abstract
Brucella consists of gram-negative bacteria that have the ability to invade and replicate in professional and non-professional phagocytes, and its prolonged persistence in the host leads to brucellosis, a serious zoonosis. Toll-like receptors (TLRs) are the best-known sensors of microorganisms implicated in the regulation of innate and adaptive immunity. In particular, TLRs are transmembrane proteins with a typical structure of an extracellular leucine-rich repeat (LRR) region and an intracellular Toll/interleukin-1 receptor (TIR) domain. In this review, we discuss Brucella infection and the aspects of host immune responses induced by pathogens. Furthermore, we summarize the roles of TLRs in Brucella infection, with substantial emphasis on the molecular insights into its mechanisms of action.
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Affiliation(s)
- Hui Yu
- Inner Mongolia Key Laboratory of Disease-Related Biomarkers, The Second Affiliated Hospital, Baotou Medical College, Baotou, China
- School of Basic Medicine, Baotou Medical College, Baotou, China
| | - Xinyi Gu
- The College of Medical Technology, Shanghai University of Medicine & Health Sciences, Shanghai, China
| | - Danfeng Wang
- The College of Medical Technology, Shanghai University of Medicine & Health Sciences, Shanghai, China
| | - Zhanli Wang
- Inner Mongolia Key Laboratory of Disease-Related Biomarkers, The Second Affiliated Hospital, Baotou Medical College, Baotou, China
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3
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Joshi K, Mazumdar V, Nandi BR, Radhakrishnan GK. Brucella targets the host ubiquitin-specific protease, Usp8, through the effector protein, TcpB, for facilitating infection of macrophages. Infect Immun 2024; 92:e0028923. [PMID: 38174929 PMCID: PMC10863413 DOI: 10.1128/iai.00289-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 11/12/2023] [Indexed: 01/05/2024] Open
Abstract
Brucella species are Gram-negative intracellular bacterial pathogens that cause the worldwide zoonotic disease brucellosis. Brucella can infect many mammals, including humans and domestic and wild animals. Brucella manipulates various host cellular processes to invade and multiply in professional and non-professional phagocytic cells. However, the host targets and their modulation by Brucella to facilitate the infection process remain obscure. Here, we report that the host ubiquitin-specific protease, USP8, negatively regulates the invasion of Brucella into macrophages through the plasma membrane receptor, CXCR4. Upon silencing or chemical inhibition of USP8, the membrane localization of the CXCR4 receptor was enriched, which augmented the invasion of Brucella into macrophages. Activation of USP8 through chemical inhibition of 14-3-3 protein affected the invasion of Brucella into macrophages. Brucella suppressed the expression of Usp8 at its early stage of infection in the infected macrophages. Furthermore, we found that only live Brucella could negatively regulate the expression of Usp8, suggesting the role of secreted effector protein of Brucella in modulating the gene expression. Subsequent studies revealed that the Brucella effector protein, TIR-domain containing protein from Brucella, TcpB, plays a significant role in downregulating the expression of Usp8 by targeting the cyclic-AMP response element-binding protein pathway. Treatment of mice with USP8 inhibitor resulted in enhanced survival of B. melitensis, whereas mice treated with CXCR4 or 14-3-3 antagonists showed a diminished bacterial load. Our experimental data demonstrate a novel role of Usp8 in the host defense against microbial intrusion. The present study provides insights into the microbial subversion of host defenses, and this information may ultimately help to develop novel therapeutic interventions for infectious diseases.
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Affiliation(s)
- Kiranmai Joshi
- Laboratory of Immunology and Microbial Pathogenesis, National Institute of Animal Biotechnology (NIAB), Hyderabad, Telangana, India
- Regional Centre for Biotechnology (RCB), Faridabad, India
| | - Varadendra Mazumdar
- Laboratory of Immunology and Microbial Pathogenesis, National Institute of Animal Biotechnology (NIAB), Hyderabad, Telangana, India
- Regional Centre for Biotechnology (RCB), Faridabad, India
| | - Binita Roy Nandi
- Laboratory of Immunology and Microbial Pathogenesis, National Institute of Animal Biotechnology (NIAB), Hyderabad, Telangana, India
- Regional Centre for Biotechnology (RCB), Faridabad, India
| | - Girish K. Radhakrishnan
- Laboratory of Immunology and Microbial Pathogenesis, National Institute of Animal Biotechnology (NIAB), Hyderabad, Telangana, India
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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: 2] [Impact Index Per Article: 2.0] [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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Klontz E, Obi JO, Wang Y, Glendening G, Carr J, Tsibouris C, Buddula S, Nallar S, Soares AS, Beckett D, Redzic JS, Eisenmesser E, Palm C, Schmidt K, Scudder AH, Obiorah T, Essuman K, Milbrandt J, Diantonio A, Ray K, Snyder MLD, Deredge D, Snyder GA. The structure of NAD + consuming protein Acinetobacter baumannii TIR domain shows unique kinetics and conformations. J Biol Chem 2023; 299:105290. [PMID: 37758001 PMCID: PMC10641520 DOI: 10.1016/j.jbc.2023.105290] [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: 05/25/2023] [Revised: 09/05/2023] [Accepted: 09/13/2023] [Indexed: 09/29/2023] Open
Abstract
Toll-like and interleukin-1/18 receptor/resistance (TIR) domain-containing proteins function as important signaling and immune regulatory molecules. TIR domain-containing proteins identified in eukaryotic and prokaryotic species also exhibit NAD+ hydrolase activity in select bacteria, plants, and mammalian cells. We report the crystal structure of the Acinetobacter baumannii TIR domain protein (AbTir-TIR) with confirmed NAD+ hydrolysis and map the conformational effects of its interaction with NAD+ using hydrogen-deuterium exchange-mass spectrometry. NAD+ results in mild decreases in deuterium uptake at the dimeric interface. In addition, AbTir-TIR exhibits EX1 kinetics indicative of large cooperative conformational changes, which are slowed down upon substrate binding. Additionally, we have developed label-free imaging using the minimally invasive spectroscopic method 2-photon excitation with fluorescence lifetime imaging, which shows differences in bacteria expressing native and mutant NAD+ hydrolase-inactivated AbTir-TIRE208A protein. Our observations are consistent with substrate-induced conformational changes reported in other TIR model systems with NAD+ hydrolase activity. These studies provide further insight into bacterial TIR protein mechanisms and their varying roles in biology.
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Affiliation(s)
- Erik Klontz
- Division of Vaccine Research, Institute of Human Virology, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Juliet O Obi
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA
| | - Yajing Wang
- Division of Vaccine Research, Institute of Human Virology, School of Medicine, University of Maryland, Baltimore, Maryland, USA; Department of Physiology, School of Basic Medical Sciences and Clinical Pharmacy, China Pharmaceutical University, Nanjing, P.R. China
| | - Gabrielle Glendening
- Division of Vaccine Research, Institute of Human Virology, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Jahid Carr
- Division of Vaccine Research, Institute of Human Virology, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Constantine Tsibouris
- Division of Vaccine Research, Institute of Human Virology, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Sahthi Buddula
- Division of Vaccine Research, Institute of Human Virology, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Shreeram Nallar
- Division of Vaccine Research, Institute of Human Virology, School of Medicine, University of Maryland, Baltimore, Maryland, USA; Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Alexei S Soares
- Brookhaven National Laboratory, National Synchrotron Light Source II, Structural Biology Program, Upton, New York, USA
| | - Dorothy Beckett
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland, USA
| | - Jasmina S Redzic
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado Denver, School of Medicine, Aurora, Colorado, USA
| | - Elan Eisenmesser
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado Denver, School of Medicine, Aurora, Colorado, USA
| | - Cheyenne Palm
- Department of Biological Sciences, Towson University, Towson, Maryland, USA
| | - Katrina Schmidt
- Department of Biological Sciences, Towson University, Towson, Maryland, USA
| | - Alexis H Scudder
- Department of Biological Sciences, Towson University, Towson, Maryland, USA
| | - Trinity Obiorah
- Department of Biological Sciences, Towson University, Towson, Maryland, USA
| | - Kow Essuman
- Department of Developmental Biology, Washington University School of Medicine, St Louis, Missouri, USA; Department of Neurosurgery, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Jeffrey Milbrandt
- Department of Developmental Biology, Washington University School of Medicine, St Louis, Missouri, USA
| | - Aaron Diantonio
- Department of Developmental Biology, Washington University School of Medicine, St Louis, Missouri, USA
| | - Krishanu Ray
- Division of Vaccine Research, Institute of Human Virology, School of Medicine, University of Maryland, Baltimore, Maryland, USA; Department of Biochemistry and Molecular Biology at the University of Maryland, School of Medicine, Baltimore, Maryland, USA
| | | | - Daniel Deredge
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA
| | - Greg A Snyder
- Division of Vaccine Research, Institute of Human Virology, School of Medicine, University of Maryland, Baltimore, Maryland, USA; Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, Maryland, USA.
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Prakash JAJ, Jacob JJ, Rachel T, Vasudevan K, Amladi A, Iyadurai R, Manesh A, Veeraraghavan B. Genomic analysis of Brucella melitensis reveals new insights into phylogeny and evolutionary divergence. Indian J Med Microbiol 2023; 44:100360. [PMID: 37356834 DOI: 10.1016/j.ijmmb.2023.02.003] [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: 08/17/2022] [Revised: 01/17/2023] [Accepted: 02/08/2023] [Indexed: 06/27/2023]
Abstract
PURPOSE Brucellosis is a bacterial zoonotic disease caused by genus Brucella. The disease is often transmitted to humans by direct or indirect contact with infected livestock or from laboratory exposure. In this study two clinical isolates of Brucella melitensis were subjected to whole genome sequencing (WGS) using Ion Torrent PGM and Oxford Nanopore MinIon platform. METHODS The two hybrid complete genomes were subjected to core gene SNP analysis to identify the relative evolutionary position. To distinguish between the various lineages of B. melitensis, Pangenome analysis was carried out. RESULTS Phylogenetic analysis revealed that both the study isolates (ST8) clustered along the other Asian isolates that formed genotype II. Genome wide analyses of 326 B melitensis isolates suggests 2171 gene clusters were shared across all the genomes while 3552 gene clusters were considered as accessory genes. CONCLUSION Here we attempted to provide the gain and loss of six unique genes that defined the phylogenetic lineages and complex evolutionary process. As the severity and prevalence of human brucellosis is increasing a better understanding of Brucella genomics and transmission dynamics is needed.
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Affiliation(s)
- John Antony Jude Prakash
- Department of Clinical Microbiology, Christian Medical College, Vellore 632004, Tamil Nadu, India.
| | - Jobin John Jacob
- Department of Clinical Microbiology, Christian Medical College, Vellore 632004, Tamil Nadu, India.
| | - Tanya Rachel
- Department of Clinical Microbiology, Christian Medical College, Vellore 632004, Tamil Nadu, India.
| | - Karthick Vasudevan
- Department of Clinical Microbiology, Christian Medical College, Vellore 632004, Tamil Nadu, India.
| | - Anushree Amladi
- Department of Clinical Microbiology, Christian Medical College, Vellore 632004, Tamil Nadu, India.
| | - Ramya Iyadurai
- Department of General Medicine Unit V, Christian Medical College and Hospital, Vellore 632004, Tamil Nadu, India.
| | - Abi Manesh
- Department of Infectious Diseases, Christian Medical College, Vellore 632004, Tamil Nadu, India.
| | - Balaji Veeraraghavan
- Department of Clinical Microbiology, Christian Medical College, Vellore 632004, Tamil Nadu, India.
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Host F-Box Protein 22 Enhances the Uptake of Brucella by Macrophages and Drives a Sustained Release of Proinflammatory Cytokines through Degradation of the Anti-Inflammatory Effector Proteins of Brucella. Infect Immun 2022; 90:e0006022. [PMID: 35420446 DOI: 10.1128/iai.00060-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Brucella species are intracellular bacterial pathogens, causing the worldwide zoonotic disease brucellosis. Brucella invades professional and nonprofessional phagocytic cells, followed by resisting intracellular killing and establishing a replication permissive niche. Brucella also modulates the innate and adaptive immune responses of the host for its chronic persistence. The complex intracellular cycle of Brucella depends in a major way on multiple host factors, but limited information is available on host and bacterial proteins that play an essential role in the invasion, intracellular replication, and modulation of host immune responses. By employing a small interfering RNA (siRNA) screening, we identified a role for the host protein FBXO22 in the Brucella-macrophage interaction. FBXO22 is the key element in the SCF E3 ubiquitination complex, where it determines the substrate specificity for ubiquitination and degradation of various host proteins. Downregulation of FBXO22 by siRNA or the CRISPR-Cas9 system resulted in diminished uptake of Brucella into macrophages, which was dependent on NF-κB-mediated regulation of phagocytic receptors. FBXO22 expression was upregulated in Brucella-infected macrophages, which resulted in induction of phagocytic receptors and enhanced production of proinflammatory cytokines through NF-κB. Furthermore, we found that FBXO22 recruits the effector proteins of Brucella, including the anti-inflammatory proteins TcpB and OMP25, for degradation through the SCF complex. We did not observe any role for another F-box-containing protein of the SCF complex, β-TrCP, in the Brucella-macrophage interaction. Our findings unravel novel functions of FBXO22 in host-pathogen interaction and its contribution to pathogenesis of infectious diseases.
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Zhang Q, Zhang Y, Wang S, Hao L, Wang S, Xu C, Jiang F, Li T. Characterization of genome-wide microRNAs and their roles in development and biotic stress in pear. PLANTA 2019; 249:693-707. [PMID: 30368557 DOI: 10.1007/s00425-018-3027-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Accepted: 10/04/2018] [Indexed: 06/08/2023]
Abstract
Using a genome-wide analysis of miRNAs in 'Yali' pear (Pyrus bretschneideri) via the next-generation high-throughput sequencing of small RNAs with a bioinformatics analysis, we found that pbr-miR156, pbr-miR164, pbr-miR399, and pbr-miR482 and their target genes function in viral defense in 'Duli' and 'Hongbaoshi'. pbr-miR160, pbr-miR168, pbr-miR171, and pbr-miR319 and their targets function in auxin signaling pathways in 'Zhongai 4' and 'Zhongai 5'. Successful fruit production in pear (Pyrus spp.) depends on the use of optimal combinations of rootstocks and scions. Deciphering plant-pathogen defense mechanisms and hormone signaling pathways is an important step towards developing pear rootstocks and varieties with improved qualities. In the current study, we combined next-generation sequencing of small RNAs with a bioinformatics analysis to systematically identify and characterize 298 miRNAs in the pear scion cultivar 'Yali' (Pyrus bretschneideri). We also analyzed miRNAs in three rootstock varieties ('Duli', 'Zhongai 4', and 'Zhongai 5') and one scion cultivar ('Hongbaoshi'). We found that pbr-miR156, pbr-miR164, pbr-miR399, and pbr-miR482 are induced following infection with the pear virus Apple stem pitting virus (ASPV), and identified their target genes (pbRPS6, pbNAC, pbTLR, and pbRX-CC, respectively), which participate in viral defense pathways in 'Duli' and 'Hongbaoshi'. Furthermore, we identified pbr-miR160, pbr-miR168, pbr-miR171, and pbr-miR319, and found that the production of these miRNAs was suppressed under low levels of synthetic auxin. The targets of these miRNAs (pbARF, pbAEC, pbSCL, and pbTCP4) respond to auxin signaling pathways in 'Zhongai 4' and 'Zhongai 5'. Our results lay the foundation for breeding improved pear cultivars.
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Affiliation(s)
- Qiulei Zhang
- Laboratory of Fruit Cell and Molecular Breeding, China Agricultural University, Beijing, 100193, China
| | - Yi Zhang
- Laboratory of Fruit Cell and Molecular Breeding, China Agricultural University, Beijing, 100193, China
| | - Shengnan Wang
- Laboratory of Fruit Cell and Molecular Breeding, China Agricultural University, Beijing, 100193, China
| | - Li Hao
- Laboratory of Fruit Cell and Molecular Breeding, China Agricultural University, Beijing, 100193, China
| | - Shengyuan Wang
- Laboratory of Fruit Cell and Molecular Breeding, China Agricultural University, Beijing, 100193, China
| | - Chaoran Xu
- Laboratory of Fruit Cell and Molecular Breeding, China Agricultural University, Beijing, 100193, China
| | - Feng Jiang
- Laboratory of Fruit Cell and Molecular Breeding, China Agricultural University, Beijing, 100193, China.
| | - Tianzhong Li
- Laboratory of Fruit Cell and Molecular Breeding, China Agricultural University, Beijing, 100193, China.
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Jakka P, Bhargavi B, Namani S, Murugan S, Splitter G, Radhakrishnan G. Cytoplasmic Linker Protein CLIP170 Negatively Regulates TLR4 Signaling by Targeting the TLR Adaptor Protein TIRAP. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2018; 200:704-714. [PMID: 29222167 PMCID: PMC5760445 DOI: 10.4049/jimmunol.1601559] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 11/05/2017] [Indexed: 02/06/2023]
Abstract
Cytoplasmic linker protein 170 (CLIP170) is a CAP-Gly domain-containing protein that is associated with the plus end of growing microtubules and implicated in various cellular processes, including the regulation of microtubule dynamics, cell migration, and intracellular transport. Our studies revealed a previously unrecognized property and role of CLIP170. We identified CLIP170 as one of the interacting partners of Brucella effector protein TcpB that negatively regulates TLR2 and TLR4 signaling. In this study, we demonstrate that CLIP170 interacts with the TLR2 and TLR4 adaptor protein TIRAP. Furthermore, our studies revealed that CLIP170 induces ubiquitination and subsequent degradation of TIRAP to negatively regulate TLR4-mediated proinflammatory responses. Overexpression of CLIP170 in mouse macrophages suppressed the LPS-induced expression of IL-6 and TNF-α whereas silencing of endogenous CLIP170 potentiated the levels of proinflammatory cytokines. In vivo silencing of CLIP170 in C57BL/6 mice by CLIP170-specific small interfering RNA enhanced LPS-induced IL-6 and TNF-α expression. Furthermore, we found that LPS modulates the expression of CLIP170 in mouse macrophages. Overall, our experimental data suggest that CLIP170 serves as an intrinsic negative regulator of TLR4 signaling that targets TIRAP.
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Affiliation(s)
- Padmaja Jakka
- National Institute of Animal Biotechnology, Hyderabad, Telangana 500049, India
- Graduate Studies, Manipal University, Manipal, Karnataka 576104, India; and
| | - Bindu Bhargavi
- National Institute of Animal Biotechnology, Hyderabad, Telangana 500049, India
| | - Swapna Namani
- National Institute of Animal Biotechnology, Hyderabad, Telangana 500049, India
| | - Subathra Murugan
- National Institute of Animal Biotechnology, Hyderabad, Telangana 500049, India
| | - Gary Splitter
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI 53706
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Jakka P, Namani S, Murugan S, Rai N, Radhakrishnan G. The Brucella effector protein TcpB induces degradation of inflammatory caspases and thereby subverts non-canonical inflammasome activation in macrophages. J Biol Chem 2017; 292:20613-20627. [PMID: 29061850 DOI: 10.1074/jbc.m117.815878] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 10/08/2017] [Indexed: 12/20/2022] Open
Abstract
The inflammasome contains intracellular receptors that recognize various pathogen-associated molecular patterns and play crucial roles in innate immune responses to invading pathogens. Non-canonical inflammasome activation is mediated by caspase-4/11, which recognizes intracellular LPS and promotes pyroptosis and secretion of proinflammatory cytokines. Brucella species are infectious intracellular pathogens that replicate in professional and non-professional phagocytic cells and subvert immune responses for chronic persistence in the host. The Brucella effector protein TcpB suppresses Toll-like receptor 2 (TLR2)- and TLR4-mediated innate immune responses by targeted degradation of the Toll/interleukin-1 receptor (TIR) domain-containing adaptor protein. TcpB is a cell-permeable protein with multiple functions, and its intracellular targets other than TIR domain-containing adaptor protein remain unclear. Here, we report that TcpB induces ubiquitination and degradation of the inflammatory caspases 1, 4, and 11. Furthermore, in both mouse and human macrophages, TcpB attenuated LPS-induced non-canonical inflammasome activation and suppressed pyroptosis and secretion of IL-1α and IL-1β induced by intracellular LPS delivery. The intact TIR domain was essential for TcpB to subvert the non-canonical inflammasome activation as a TcpB(G158A) mutant failed to suppress pyroptotic cell death and inflammatory responses. Brucella-infected macrophages exhibited minimal pyroptosis but secreted IL-1β, which was suppressed by TcpB. We also demonstrated that TcpB protein can efficiently attenuate Salmonella enterica serovar Typhimurium-induced pyroptosis and proinflammatory cytokine secretion in macrophages. Because TcpB suppresses both TLR4- and caspase-4/11-mediated inflammation, TcpB might be a candidate target for developing drugs against LPS-induced septicemia.
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Affiliation(s)
- Padmaja Jakka
- From the Laboratory of Immunology and Microbial Pathogenesis, National Institute of Animal Biotechnology, Hyderabad, Telangana 500049, India and.,Graduate Studies, Manipal University, Manipal, Karnataka 576104, India
| | - Swapna Namani
- From the Laboratory of Immunology and Microbial Pathogenesis, National Institute of Animal Biotechnology, Hyderabad, Telangana 500049, India and
| | - Subathra Murugan
- From the Laboratory of Immunology and Microbial Pathogenesis, National Institute of Animal Biotechnology, Hyderabad, Telangana 500049, India and
| | - Nivedita Rai
- From the Laboratory of Immunology and Microbial Pathogenesis, National Institute of Animal Biotechnology, Hyderabad, Telangana 500049, India and
| | - Girish Radhakrishnan
- From the Laboratory of Immunology and Microbial Pathogenesis, National Institute of Animal Biotechnology, Hyderabad, Telangana 500049, India and
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11
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Imbert PR, Louche A, Luizet JB, Grandjean T, Bigot S, Wood TE, Gagné S, Blanco A, Wunderley L, Terradot L, Woodman P, Garvis S, Filloux A, Guery B, Salcedo SP. A Pseudomonas aeruginosa TIR effector mediates immune evasion by targeting UBAP1 and TLR adaptors. EMBO J 2017; 36:1869-1887. [PMID: 28483816 PMCID: PMC5494471 DOI: 10.15252/embj.201695343] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 03/29/2017] [Accepted: 04/05/2017] [Indexed: 12/11/2022] Open
Abstract
Bacterial pathogens often subvert the innate immune system to establish a successful infection. The direct inhibition of downstream components of innate immune pathways is particularly well documented but how bacteria interfere with receptor proximal events is far less well understood. Here, we describe a Toll/interleukin 1 receptor (TIR) domain‐containing protein (PumA) of the multi‐drug resistant Pseudomonas aeruginosa PA7 strain. We found that PumA is essential for virulence and inhibits NF‐κB, a property transferable to non‐PumA strain PA14, suggesting no additional factors are needed for PumA function. The TIR domain is able to interact with the Toll‐like receptor (TLR) adaptors TIRAP and MyD88, as well as the ubiquitin‐associated protein 1 (UBAP1), a component of the endosomal‐sorting complex required for transport I (ESCRT‐I). These interactions are not spatially exclusive as we show UBAP1 can associate with MyD88, enhancing its plasma membrane localization. Combined targeting of UBAP1 and TLR adaptors by PumA impedes both cytokine and TLR receptor signalling, highlighting a novel strategy for innate immune evasion.
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Affiliation(s)
- Paul Rc Imbert
- Laboratory of Molecular Microbiology and Structural Biochemistry, Centre National de la Recherche Scientifique, University of Lyon, Lyon, France
| | - Arthur Louche
- Laboratory of Molecular Microbiology and Structural Biochemistry, Centre National de la Recherche Scientifique, University of Lyon, Lyon, France
| | - Jean-Baptiste Luizet
- Laboratory of Molecular Microbiology and Structural Biochemistry, Centre National de la Recherche Scientifique, University of Lyon, Lyon, France
| | - Teddy Grandjean
- EA 7366 Recherche Translationelle Relations Hôte-Pathogènes, Faculté de Médecine Pôle Recherche, Université Lille 2, Lille, France
| | - Sarah Bigot
- Laboratory of Molecular Microbiology and Structural Biochemistry, Centre National de la Recherche Scientifique, University of Lyon, Lyon, France
| | - Thomas E Wood
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Stéphanie Gagné
- Laboratory of Molecular Microbiology and Structural Biochemistry, Centre National de la Recherche Scientifique, University of Lyon, Lyon, France
| | - Amandine Blanco
- Laboratory of Molecular Microbiology and Structural Biochemistry, Centre National de la Recherche Scientifique, University of Lyon, Lyon, France
| | - Lydia Wunderley
- School of Biological Sciences, Faculty of Biology Medicine and Health University of Manchester Manchester Academic Health Science Centre, Manchester, UK†
| | - Laurent Terradot
- Laboratory of Molecular Microbiology and Structural Biochemistry, Centre National de la Recherche Scientifique, University of Lyon, Lyon, France
| | - Philip Woodman
- School of Biological Sciences, Faculty of Biology Medicine and Health University of Manchester Manchester Academic Health Science Centre, Manchester, UK†
| | - Steve Garvis
- Laboratoire de Biologie et Modelisation, Ecole Normal Supérieur, UMR5239, Lyon, France
| | - Alain Filloux
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Benoit Guery
- EA 7366 Recherche Translationelle Relations Hôte-Pathogènes, Faculté de Médecine Pôle Recherche, Université Lille 2, Lille, France
| | - Suzana P Salcedo
- Laboratory of Molecular Microbiology and Structural Biochemistry, Centre National de la Recherche Scientifique, University of Lyon, Lyon, France
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12
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Kaplan-Türköz B. A putative Toll/interleukin-1 receptor domain protein fromHelicobacter pyloriis dimeric in solution and interacts with human Toll-like receptor adaptor myeloid differentiation primary response 88. Microbiol Immunol 2017; 61:85-91. [DOI: 10.1111/1348-0421.12469] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 02/03/2017] [Accepted: 02/10/2017] [Indexed: 12/26/2022]
Affiliation(s)
- Burcu Kaplan-Türköz
- Department of Food Engineering; Faculty of Engineering; Ege University; 35100, Bornova İzmir Turkey
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13
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Hashemifar I, Yadegar A, Jazi FM, Amirmozafari N. Molecular prevalence of putative virulence-associated genes in Brucella melitensis and Brucella abortus isolates from human and livestock specimens in Iran. Microb Pathog 2017; 105:334-339. [PMID: 28284850 DOI: 10.1016/j.micpath.2017.03.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 03/03/2017] [Accepted: 03/06/2017] [Indexed: 01/08/2023]
Abstract
Molecular prevalence of nine putative virulence factors in two more prevalent Brucella species in Iranian patients and livestock was investigated. During five years (2010-2015), 120 human and animal specimens were collected from three geographical areas of Iran. All samples were cultured in blood culture media and subcultured into Brucella agar medium. Nine primer pairs were designed for detection of VirB2, VirB5, VceC, BtpA, BtpB, PrpA, BetB, BPE275 and BSPB virulence factors using PCR and sequence analysis. Totally, 68 Brucella isolates including 60 B. melitensis and 8 B. abortus were isolated from the human and animal specimens examined. Approximately, all B. melitensis and B. abortus strains were positive (100%) regarding btpA, btpB, virB5, vceC, bpe275, bspB, and virB2 genes except for prpA and betB that were detected in 86% and 97% of the strains, respectively. Significant relationships were found between the presence of prpA and human B. melitensis isolates (P = 0.04), and also between the presence of betB and human isolates of B. abortus (P = 0.03). In conclusion, our results revealed that Iranian Brucella strains, regardless of human or animal sources, are extremely virulent due to high prevalence of virulence attributes in almost all strains studied.
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Affiliation(s)
- Iman Hashemifar
- Microbiology Department, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Abbas Yadegar
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Faramarz Masjedian Jazi
- Microbiology Department, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Nour Amirmozafari
- Microbiology Department, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
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14
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Carlsson E, Thwaite JE, Jenner DC, Spear AM, Flick-Smith H, Atkins HS, Byrne B, Ding JL. Bacillus anthracis TIR Domain-Containing Protein Localises to Cellular Microtubule Structures and Induces Autophagy. PLoS One 2016; 11:e0158575. [PMID: 27391310 PMCID: PMC4938393 DOI: 10.1371/journal.pone.0158575] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 06/17/2016] [Indexed: 02/06/2023] Open
Abstract
Toll-like receptors (TLRs) recognise invading pathogens and mediate downstream immune signalling via Toll/IL-1 receptor (TIR) domains. TIR domain proteins (Tdps) have been identified in multiple pathogenic bacteria and have recently been implicated as negative regulators of host innate immune activation. A Tdp has been identified in Bacillus anthracis, the causative agent of anthrax. Here we present the first study of this protein, designated BaTdp. Recombinantly expressed and purified BaTdp TIR domain interacted with several human TIR domains, including that of the key TLR adaptor MyD88, although BaTdp expression in cultured HEK293 cells had no effect on TLR4- or TLR2- mediated immune activation. During expression in mammalian cells, BaTdp localised to microtubular networks and caused an increase in lipidated cytosolic microtubule-associated protein 1A/1B-light chain 3 (LC3), indicative of autophagosome formation. In vivo intra-nasal infection experiments in mice showed that a BaTdp knockout strain colonised host tissue faster with higher bacterial load within 4 days post-infection compared to the wild type B. anthracis. Taken together, these findings indicate that BaTdp does not play an immune suppressive role, but rather, its absence increases virulence. BaTdp present in wild type B. anthracis plausibly interact with the infected host cell, which undergoes autophagy in self-defence.
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Affiliation(s)
- Emil Carlsson
- Department of Life Sciences, Imperial College London, London, United Kingdom
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore
| | - Joanne E. Thwaite
- Defence Science and Technology Laboratory, Porton Down, Salisbury, United Kingdom
| | - Dominic C. Jenner
- Defence Science and Technology Laboratory, Porton Down, Salisbury, United Kingdom
| | - Abigail M. Spear
- Defence Science and Technology Laboratory, Porton Down, Salisbury, United Kingdom
| | - Helen Flick-Smith
- Defence Science and Technology Laboratory, Porton Down, Salisbury, United Kingdom
| | - Helen S. Atkins
- Defence Science and Technology Laboratory, Porton Down, Salisbury, United Kingdom
| | - Bernadette Byrne
- Department of Life Sciences, Imperial College London, London, United Kingdom
- * E-mail: (JLD); (BB)
| | - Jeak Ling Ding
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore
- * E-mail: (JLD); (BB)
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15
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Brucella TIR-like protein TcpB/Btp1 specifically targets the host adaptor protein MAL/TIRAP to promote infection. Biochem Biophys Res Commun 2016; 477:509-14. [PMID: 27311859 DOI: 10.1016/j.bbrc.2016.06.064] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 06/13/2016] [Indexed: 02/06/2023]
Abstract
Brucella spp. are known to avoid host immune recognition and weaken the immune response to infection. Brucella like accomplish this by employing two clever strategies, called the stealth strategy and hijacking strategy. The TIR domain-containing protein (TcpB/Btp1) of Brucella melitensis is thought to be involved in inhibiting host NF-κB activation by binding to adaptors downstream of Toll-like receptors. However, of the five TIR domain-containing adaptors conserved in mammals, whether MyD88 or MAL, even other three adaptors, are specifically targeted by TcpB has not been identified. Here, we confirmed the effect of TcpB on B.melitensis virulence in mice and found that TcpB selectively targets MAL. By using siRNA against MAL, we found that TcpB from B.melitensis is involved in intracellular survival and that MAL affects intracellular replication of B.melitensis. Our results confirm that TcpB specifically targets MAL/TIRAP to disrupt downstream signaling pathways and promote intra-host survival of Brucella spp.
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16
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Ahmed W, Zheng K, Liu ZF. Establishment of Chronic Infection: Brucella's Stealth Strategy. Front Cell Infect Microbiol 2016; 6:30. [PMID: 27014640 PMCID: PMC4791395 DOI: 10.3389/fcimb.2016.00030] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 02/29/2016] [Indexed: 01/18/2023] Open
Abstract
Brucella is a facultative intracellular pathogen that causes zoonotic infection known as brucellosis which results in abortion and infertility in natural host. Humans, especially in low income countries, can acquire infection by direct contact with infected animal or by consumption of animal products and show high morbidity, severe economic losses and public health problems. However for survival, host cells develop complex immune mechanisms to defeat and battle against attacking pathogens and maintain a balance between host resistance and Brucella virulence. On the other hand as a successful intracellular pathogen, Brucella has evolved multiple strategies to evade immune response mechanisms to establish persistent infection and replication within host. In this review, we mainly summarize the "Stealth" strategies employed by Brucella to modulate innate and the adaptive immune systems, autophagy, apoptosis and possible role of small noncoding RNA in the establishment of chronic infection. The purpose of this review is to give an overview for recent understanding how this pathogen evades immune response mechanisms of host, which will facilitate to understanding the pathogenesis of brucellosis and the development of novel, more effective therapeutic approaches to treat brucellosis.
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Affiliation(s)
- Waqas Ahmed
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China
| | - Ke Zheng
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China
| | - Zheng-Fei Liu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China
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17
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Ke Y, Wang Y, Li W, Chen Z. Type IV secretion system of Brucella spp. and its effectors. Front Cell Infect Microbiol 2015; 5:72. [PMID: 26528442 PMCID: PMC4602199 DOI: 10.3389/fcimb.2015.00072] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Accepted: 09/28/2015] [Indexed: 11/13/2022] Open
Abstract
Brucella spp. are intracellular bacterial pathogens that cause infection in domestic and wild animals. They are often used as model organisms to study intracellular bacterial infections. Brucella VirB T4SS is a key virulence factor that plays important roles in mediating intracellular survival and manipulating host immune response to infection. In this review, we discuss the roles of Brucella VirB T4SS and 15 effectors that are proposed to be crucial for Brucella pathogenesis. VirB T4SS regulates the inflammation response and manipulates vesicle trafficking inside host cells. VirB T4SS also plays crucial roles in the inhibition of the host immune response and intracellular survival during infection. Here, we list the key molecular events in the intracellular life cycle of Brucella that are potentially targeted by the VirB T4SS effectors. Elucidating the functions of these effectors will help clarify the molecular role of T4SS during infection. Furthermore, studying the effectors secreted by Brucella spp. might provide insights into the mechanisms used by the bacteria to hijack the host signaling pathways and aid in the development of better vaccines and therapies against brucellosis.
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Affiliation(s)
- Yuehua Ke
- Institute of Disease Control and Prevention, AMMS Beijing, China
| | - Yufei Wang
- Department of Laboratory Medicine, General Hospital of Chinese People's Armed Police Forces Beijing, China
| | - Wengfeng Li
- Department of Orthopedics, The First Affiliated Hospital of General Hospital of People's Liberation Army Beijing, China
| | - Zeliang Chen
- Institute of Disease Control and Prevention, AMMS Beijing, China
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18
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Patterson NJ, Günther J, Gibson AJ, Offord V, Coffey TJ, Splitter G, Monk I, Seyfert HM, Werling D. Two TIR-like domain containing proteins in a newly emerging zoonotic Staphylococcus aureus strain sequence type 398 are potential virulence factors by impacting on the host innate immune response. Front Microbiol 2014; 5:662. [PMID: 25538689 PMCID: PMC4260764 DOI: 10.3389/fmicb.2014.00662] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 11/14/2014] [Indexed: 12/24/2022] Open
Abstract
Staphylococcus aureus, sequence type (ST) 398, is an emerging pathogen and the leading cause of livestock-associated methicillin-resistant S. aureus infections in Europe and North America. This strain is characterized by high promiscuity in terms of host-species and also lacks several traditional S. aureus virulence factors. This does not, however, explain the apparent ease with which it crosses species-barriers. Recently, TIR-domain containing proteins (Tcps) which inhibit the innate immune response were identified in some Gram-negative bacteria. Here we report the presence of two proteins, S. aureus TIR-like Protein 1 (SaTlp1) and S. aureus TIR-like Protein 2 (SaTlp2), expressed by ST398 which contain domain of unknown function 1863 (DUF1863), similar to the Toll/IL-1 receptor (TIR) domain. In contrast to the Tcps in Gram-negative bacteria, our data suggest that SaTlp1 and SaTlp2 increase activation of the transcription factor NF-κB as well as downstream pro-inflammatory cytokines and immune effectors. To assess the role of both proteins as potential virulence factors knock-out mutants were created. These showed a slightly enhanced survival rate in a murine infectious model compared to the wild-type strain at one dose. Our data suggest that both proteins may act as factors contributing to the enhanced ability of ST398 to cross species-barriers.
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Affiliation(s)
- Nicholas J Patterson
- Molecular Immunology Group, Department of Pathology and Pathogen Biology, Royal Veterinary College Hatfield, UK
| | - Juliane Günther
- Leibniz Institute for Farm Animal Biology Dummerstorf, Germany
| | - Amanda J Gibson
- Molecular Immunology Group, Department of Pathology and Pathogen Biology, Royal Veterinary College Hatfield, UK
| | - Victoria Offord
- Molecular Immunology Group, Department of Pathology and Pathogen Biology, Royal Veterinary College Hatfield, UK
| | - Tracey J Coffey
- School of Veterinary Medicine and Sciences, Faculty of Medicine and Health Sciences, University of Nottingham Sutton Bonington, UK
| | - Gary Splitter
- Department of Pathobiological Sciences, University of Wisconsin-Madison Madison, WI, USA
| | - Ian Monk
- Department of Microbiology and Immunology, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne Melbourne, VIC, Australia
| | | | - Dirk Werling
- Molecular Immunology Group, Department of Pathology and Pathogen Biology, Royal Veterinary College Hatfield, UK
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19
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Zou J, Baghdayan AS, Payne SJ, Shankar N. A TIR domain protein from E. faecalis attenuates MyD88-mediated signaling and NF-κB activation. PLoS One 2014; 9:e112010. [PMID: 25369374 PMCID: PMC4219826 DOI: 10.1371/journal.pone.0112010] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 10/12/2014] [Indexed: 12/13/2022] Open
Abstract
Toll-like receptor signaling, mediated by functional Toll/interleukin-1 receptor (TIR) domains, plays a critical role in activating the innate immune response responsible for controlling and clearing infection. Bacterial protein mimics of components of this signaling pathway have been identified and function through inhibition of interactions between Toll-like receptors (TLRs) and their adaptor proteins, mediated by TIR domains. A previously uncharacterized gene, which we have named tcpF (for TIR domain-containing protein in E. faecalis) was identified in the genome of Enterococcus faecalis V583, and predicted to encode a protein resembling mammalian and bacterial TIR proteins. We overexpressed and purified TcpF from E. coli and found that the recombinant protein could bind to phosphatidylinositol phosphates in vitro, suggesting a mechanism by which TcpF may be anchored to the plasma membrane in close proximity to TIR domains of TLRs and adaptor proteins. Purified TcpF was also found to interact specifically with the TIR adaptor protein MyD88, and this interaction was dependent on the BB loop domain in the Box 2 region of TcpF. Despite no evidence of TcpF being a secreted protein, recombinant TcpF was effectively able to enter RAW264.7 cells in vitro although the mechanism by which this occurs remains to be determined. Overexpression of TcpF in mammalian cells suppressed the NF-κB activation induced by bacterial lipoteichoic acid. A mutant lacking the tcpF gene was attenuated for survival in macrophages, with increased ability to activate NF-κB compared to the wild type strain. Complementation in trans restored growth, and inhibition of NF-κB, to that of wild type levels. No appreciable difference in bacterial persistence, dissemination or pathogenesis was observed between the wild type and mutant in a mouse peritonitis model however, which suggested either a subtle role for TcpF or functional overlap with other redundant factor(s) in this virulence model.
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Affiliation(s)
- Jun Zou
- Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Arto S. Baghdayan
- Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Sarah J. Payne
- Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Nathan Shankar
- Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- * E-mail:
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20
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Felix C, Kaplan Türköz B, Ranaldi S, Koelblen T, Terradot L, O'Callaghan D, Vergunst AC. The Brucella TIR domain containing proteins BtpA and BtpB have a structural WxxxE motif important for protection against microtubule depolymerisation. Cell Commun Signal 2014; 12:53. [PMID: 25304327 PMCID: PMC4203976 DOI: 10.1186/s12964-014-0053-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 08/27/2014] [Indexed: 01/12/2023] Open
Abstract
Background The TIR domain-containing proteins BtpA/Btp1/TcpB and BtpB are translocated into host cells by the facultative intracellular bacterial pathogen Brucella. Here, they interfere with Toll like receptor signalling to temper the host inflammatory response. BtpA has also been found to modulate microtubule dynamics. In both proteins we identified a WxxxE motif, previously shown to be an essential structural component in a family of bacterial type III secretion system effectors that modulate host actin dynamics by functioning as guanine nucleotide exchange factors of host GTPases. We analysed a role for the WxxxE motif in association of BtpA and BtpB with the cytoskeleton. Results Unlike BtpA, ectopically expressed BtpB did not show a tubular localisation, but was found ubiquitously in the cytoplasm and the nucleus, and often appeared in discrete punctae in HeLa cells. BtpB was able to protect microtubules from drug-induced destabilisation similar to BtpA. The WxxxE motif was important for the ability of BtpA and BtpB to protect microtubules against destabilising drugs. Surprisingly, ectopic expression of BtpA, although not BtpB, in HeLa cells induced the formation of filopodia. This process was invariably dependent of the WxxxE motif. Our recent resolution of the crystal structure of the BtpA TIR domain reveals that the motif positions a glycine residue that has previously been shown to be essential for interaction of BtpA with microtubules. Conclusions Our results suggest a structural role for the WxxxE motif in the association of BtpA and BtpB with microtubules, as with the WxxxE GEF family proteins where the motif positions an adjacent catalytic loop important for interaction with specific Rho GTPases. In addition, the ability of ectopically expressed BtpA to induce filopodia in a WxxxE-dependent manner suggests a novel property for BtpA. A conserved WxxxE motif is found in most bacterial and several eukaryotic TIR domain proteins. Despite the similarity between ectopically expressed BtpA and WxxxE GEFs to modulate host actin dynamics, our results suggest that BtpA is not part of this WxxxE GEF family. The WxxxE motif may therefore be a more common structural motif than thus far described. BtpA may provide clues to cross-talk between the TLR and GTPase signalling pathways. Electronic supplementary material The online version of this article (doi:10.1186/s12964-014-0053-y) contains supplementary material, which is available to authorized users.
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21
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The TIR Domain Containing Locus of Enterococcus faecalis Is Predominant among Urinary Tract Infection Isolates and Downregulates Host Inflammatory Response. Int J Microbiol 2014; 2014:918143. [PMID: 25147569 PMCID: PMC4131471 DOI: 10.1155/2014/918143] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 06/11/2014] [Accepted: 06/30/2014] [Indexed: 12/18/2022] Open
Abstract
Based on Toll/interleukin-1 receptor (TIR) domain structure homology, we detected a previously uncharacterized gene encoding for a TIR domain containing protein (Tcp) in the genome of Enterococcus faecalis. We assigned this gene the name tcpF (as in Tcp of E. faecalis). Screening of E. faecalis samples revealed that tcpF is more common in isolates from urinary tract infections (UTIs) than in human faecal flora. tcpF alleles showed moderate single nucleotide polymorphism (SNP) among UTI isolates. Infection of mouse RAW264.7 macrophages with a tcpF knock-out mutant led to elevated cytokine response compared to the isogenic wild type E. faecalis strain. In silico analysis predicted significant tertiary structure homology to the TIR domain of human TLR1 (TLR1-TIR). When transiently expressed in cultured eukaryotic cells, TcpF caused suppression of TLR2-dependent NF-κB activation suggesting for TcpF a role as a factor in E. faecalis that benefits colonization by modulating the host's immune responses.
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22
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Wattam AR, Foster JT, Mane SP, Beckstrom-Sternberg SM, Beckstrom-Sternberg JM, Dickerman AW, Keim P, Pearson T, Shukla M, Ward DV, Williams KP, Sobral BW, Tsolis RM, Whatmore AM, O'Callaghan D. Comparative phylogenomics and evolution of the Brucellae reveal a path to virulence. J Bacteriol 2014; 196:920-30. [PMID: 24336939 PMCID: PMC3957692 DOI: 10.1128/jb.01091-13] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 12/04/2013] [Indexed: 11/20/2022] Open
Abstract
Brucella species include important zoonotic pathogens that have a substantial impact on both agriculture and human health throughout the world. Brucellae are thought of as "stealth pathogens" that escape recognition by the host innate immune response, modulate the acquired immune response, and evade intracellular destruction. We analyzed the genome sequences of members of the family Brucellaceae to assess its evolutionary history from likely free-living soil-based progenitors into highly successful intracellular pathogens. Phylogenetic analysis split the genus into two groups: recently identified and early-dividing "atypical" strains and a highly conserved "classical" core clade containing the major pathogenic species. Lateral gene transfer events brought unique genomic regions into Brucella that differentiated them from Ochrobactrum and allowed the stepwise acquisition of virulence factors that include a type IV secretion system, a perosamine-based O antigen, and systems for sequestering metal ions that are absent in progenitors. Subsequent radiation within the core Brucella resulted in lineages that appear to have evolved within their preferred mammalian hosts, restricting their virulence to become stealth pathogens capable of causing long-term chronic infections.
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Affiliation(s)
- Alice R. Wattam
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, USA
| | - Jeffrey T. Foster
- Center for Microbial Genetics & Genomics, Northern Arizona University, Flagstaff, Arizona, USA
| | | | - Stephen M. Beckstrom-Sternberg
- Center for Microbial Genetics & Genomics, Northern Arizona University, Flagstaff, Arizona, USA
- Translational Genomics Research Institute, Pathogen Genomics Division, Phoenix, Arizona, USA
| | - James M. Beckstrom-Sternberg
- Center for Microbial Genetics & Genomics, Northern Arizona University, Flagstaff, Arizona, USA
- Translational Genomics Research Institute, Pathogen Genomics Division, Phoenix, Arizona, USA
| | - Allan W. Dickerman
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, USA
| | - Paul Keim
- Center for Microbial Genetics & Genomics, Northern Arizona University, Flagstaff, Arizona, USA
- Translational Genomics Research Institute, Pathogen Genomics Division, Phoenix, Arizona, USA
| | - Talima Pearson
- Center for Microbial Genetics & Genomics, Northern Arizona University, Flagstaff, Arizona, USA
| | - Maulik Shukla
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, USA
| | - Doyle V. Ward
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Kelly P. Williams
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, USA
| | - Bruno W. Sobral
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, USA
| | - Renee M. Tsolis
- Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, California, USA
| | - Adrian M. Whatmore
- Department of Bacteriology, Animal Health & Veterinary Laboratories Agency, Addlestone, United Kingdom
| | - David O'Callaghan
- INSERM U1047, UFR Médecine, Nîmes, France
- Université Montpellier 1, UFR Médecine, Nîmes, France
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Askarian F, van Sorge NM, Sangvik M, Beasley FC, Henriksen JR, Sollid JUE, van Strijp JAG, Nizet V, Johannessen M. A Staphylococcus aureus TIR domain protein virulence factor blocks TLR2-mediated NF-κB signaling. J Innate Immun 2014; 6:485-98. [PMID: 24481289 DOI: 10.1159/000357618] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 11/25/2013] [Indexed: 01/05/2023] Open
Abstract
Signaling through Toll-like receptors (TLRs), crucial molecules in the induction of host defense responses, requires adaptor proteins that contain a Toll/interleukin-1 receptor (TIR) domain. The pathogen Staphylococcus aureus produces several innate immune-evasion molecules that interfere with the host's innate immune response. A database search analysis suggested the presence of a gene encoding a homologue of the human TIR domain in S. aureus MSSA476 which was named staphylococcal TIR domain protein (TirS). Ectopic expression of TirS in human embryonic kidney, macrophage and keratinocyte cell lines interfered with signaling through TLR2, including MyD88 and TIRAP, NF-κB and/or mitogen-activated protein kinase pathways. Moreover, the presence of TirS reduced the levels of cytokines MCP-1 and G-CSF secreted in response to S. aureus. The effects on NF-κB pathway were confirmed using S. aureus MSSA476 wild type, an isogenic mutant MSSA476ΔtirS, and complemented MSSA476ΔtirS +pTirS in a Transwell system where bacteria and host cells were physically separated. Finally, in a systematic mouse infection model, TirS promoted bacterial accumulation in several organs 4 days postinfection. The results of this study reveal a new S. aureus virulence factor that can interfere with PAMP-induced innate immune signaling in vitro and bacterial survival in vivo.
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Affiliation(s)
- Fatemeh Askarian
- Research Group of Host-Microbe Interactions, Department of Medical Biology, Faculty of Health Sciences, UiT The Artic University of Norway, Tromsø, Norway
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24
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Snyder GA, Deredge D, Waldhuber A, Fresquez T, Wilkins DZ, Smith PT, Durr S, Cirl C, Jiang J, Jennings W, Luchetti T, Snyder N, Sundberg EJ, Wintrode P, Miethke T, Xiao TS. Crystal structures of the Toll/Interleukin-1 receptor (TIR) domains from the Brucella protein TcpB and host adaptor TIRAP reveal mechanisms of molecular mimicry. J Biol Chem 2013; 289:669-79. [PMID: 24275656 DOI: 10.1074/jbc.m113.523407] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Toll/IL-1 receptor (TIR) domains are crucial innate immune signaling modules. Microbial TIR domain-containing proteins inhibit Toll-like receptor (TLR) signaling through molecular mimicry. The TIR domain-containing protein TcpB from Brucella inhibits TLR signaling through interaction with host adaptor proteins TIRAP/Mal and MyD88. To characterize the microbial mimicry of host proteins, we have determined the X-ray crystal structures of the TIR domains from the Brucella protein TcpB and the host adaptor protein TIRAP. We have further characterized homotypic interactions of TcpB using hydrogen/deuterium exchange mass spectrometry and heterotypic TcpB and TIRAP interaction by co-immunoprecipitation and NF-κB reporter assays. The crystal structure of the TcpB TIR domain reveals the microtubule-binding site encompassing the BB loop as well as a symmetrical dimer mediated by the DD and EE loops. This dimerization interface is validated by peptide mapping through hydrogen/deuterium exchange mass spectrometry. The human TIRAP TIR domain crystal structure reveals a unique N-terminal TIR domain fold containing a disulfide bond formed by Cys(89) and Cys(134). A comparison between the TcpB and TIRAP crystal structures reveals substantial conformational differences in the region that encompasses the BB loop. These findings underscore the similarities and differences in the molecular features found in the microbial and host TIR domains, which suggests mechanisms of bacterial mimicry of host signaling adaptor proteins, such as TIRAP.
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Affiliation(s)
- Greg A Snyder
- From the Laboratory of Immunology, NIAID, National Institutes of Health, Bethesda, Maryland 20892
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25
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Alaidarous M, Ve T, Ullah MO, Valkov E, Mansell A, Schembri MA, Sweet MJ, Kobe B. Cloning, expression, purification, crystallization and preliminary X-ray crystallographic analysis of the TIR domain from the Brucella melitensis TIR-domain-containing protein TcpB. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:1167-70. [PMID: 24100574 PMCID: PMC3792682 DOI: 10.1107/s1744309113024408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 09/02/2013] [Indexed: 01/23/2023]
Abstract
In mammals, Toll-like receptors (TLRs) recognize conserved microbial molecular signatures and induce an early innate immune response in the host. TLR signalling is mediated by interactions between the cytosolic TIR (Toll/interleukin-1 receptor) domains of the receptor and the adaptor proteins. Increasingly, it is apparent that pathogens target this interaction via pathogen-expressed TIR-domain-containing proteins to modulate immune responses. A TIR-domain-containing protein TcpB has been reported in the pathogenic bacterium Brucella melitensis. Studies have shown that TcpB interferes with the TLR2 and TLR4 signalling pathways to inhibit TLR-mediated inflammatory responses. Such interference may involve TIR-TIR-domain interactions between bacterial and mammalian proteins, but there is a lack of information about these interactions at the molecular level. In this study, the cloning, expression, purification, crystallization and preliminary X-ray crystallographic analysis of the protein construct corresponding to the TIR domain of TcpB (residues 120-250) are reported. The crystals diffracted to 2.6 Å resolution, have the symmetry of the monoclinic space group P2₁ and are most likely to contain four molecules in the asymmetric unit. The structure should help in understanding the molecular basis of how TcpB affects the innate immunity of the host.
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Affiliation(s)
- Mohammed Alaidarous
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia
| | - Thomas Ve
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia
| | - M. Obayed Ullah
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia
| | - Eugene Valkov
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, England
| | - Ashley Mansell
- Centre for Innate Immunity and Infectious Diseases, Monash Institute of Medical Research, Monash University, Melbourne, VIC 3168, Australia
| | - Mark A. Schembri
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia
| | - Matthew J. Sweet
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia
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26
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Patterson NJ, Werling D. To con protection: TIR-domain containing proteins (Tcp) and innate immune evasion. Vet Immunol Immunopathol 2013; 155:147-54. [PMID: 23871438 DOI: 10.1016/j.vetimm.2013.06.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Revised: 06/17/2013] [Accepted: 06/26/2013] [Indexed: 01/07/2023]
Abstract
The innate immune system provides the host's first line of defence against invading pathogens. Key to the stimulation of the innate immune response is pattern-recognition receptors (PRRs), such as Toll-like receptors (TLRs), which recognize microbial-associated molecular patterns (MAMPs). Binding of MAMPs to TLRs triggers a signalling cascade resulting in the production of pro-inflammatory mediators. Central to this TLR signalling pathway are heterotypic protein-protein interactions mediated through Toll/interleukin-1 receptor (TIR) domains found in both the cytoplasmic regions of TLRs and several key adaptor proteins. Interestingly, TIR-domain containing proteins (Tcps) do not seem to be unique to the mammalian TLR system, but occurs in abundance in many biological forms. Recent evidence suggests that pathogenic bacteria have developed a range of ingenuous strategies to evade the host immune mechanisms involving Tcps. There is increasing evidence to suggest that these pathogen-encoded Tcps interfere directly with the TLR signalling pathway and thus inhibit the activation of NF-κB, with different modes of action and roles in virulence. Here, we review the current state of knowledge on the possible roles and mechanisms of action of bacterial encoded Tcp.
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Affiliation(s)
- Nicholas J Patterson
- Molecular Immunology Group, Department of Pathology and Pathogen Biology, Royal Veterinary College, Hawkshead Lane, Hatfield AL9 7TA, UK
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27
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Nandety RS, Caplan JL, Cavanaugh K, Perroud B, Wroblewski T, Michelmore RW, Meyers BC. The role of TIR-NBS and TIR-X proteins in plant basal defense responses. PLANT PHYSIOLOGY 2013; 162:1459-72. [PMID: 23735504 PMCID: PMC3707564 DOI: 10.1104/pp.113.219162] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Accepted: 06/01/2013] [Indexed: 05/02/2023]
Abstract
Toll/interleukin receptor (TIR) domain-containing proteins encoded in the Arabidopsis (Arabidopsis thaliana) genome include the TIR-nucleotide binding site (TN) and TIR-unknown site/domain (TX) families. We investigated the function of these proteins. Transient overexpression of five TX and TN genes in tobacco (Nicotiana benthamiana) induced chlorosis. This induced chlorosis was dependent on ENHANCED DISEASE RESISTANCE1, a dependency conserved in both tobacco and Arabidopsis. Stable overexpression transgenic lines of TX and TN genes in Arabidopsis produced a variety of phenotypes associated with basal innate immune responses; these were correlated with elevated levels of salicylic acid. The TN protein AtTN10 interacted with the chloroplastic protein phosphoglycerate dehydrogenase in a yeast (Saccharomyces cerevisiae) two-hybrid screen; other TX and TN proteins interacted with nucleotide binding-leucine-rich repeat proteins and effector proteins, suggesting that TN proteins might act in guard complexes monitoring pathogen effectors.
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Affiliation(s)
| | - Jeffery L. Caplan
- Department of Plant and Soil Sciences (R.S.N., B.C.M.), and Delaware Biotechnology Institute (R.S.N., J.L.C., B.C.M.), University of Delaware, Newark, Delaware 19711; and
- UC Davis Genome Center, University of California, Davis, California 95616 (K.C., B.P., T.W., R.W.M.)
| | - Keri Cavanaugh
- Department of Plant and Soil Sciences (R.S.N., B.C.M.), and Delaware Biotechnology Institute (R.S.N., J.L.C., B.C.M.), University of Delaware, Newark, Delaware 19711; and
- UC Davis Genome Center, University of California, Davis, California 95616 (K.C., B.P., T.W., R.W.M.)
| | - Bertrand Perroud
- Department of Plant and Soil Sciences (R.S.N., B.C.M.), and Delaware Biotechnology Institute (R.S.N., J.L.C., B.C.M.), University of Delaware, Newark, Delaware 19711; and
- UC Davis Genome Center, University of California, Davis, California 95616 (K.C., B.P., T.W., R.W.M.)
| | - Tadeusz Wroblewski
- Department of Plant and Soil Sciences (R.S.N., B.C.M.), and Delaware Biotechnology Institute (R.S.N., J.L.C., B.C.M.), University of Delaware, Newark, Delaware 19711; and
- UC Davis Genome Center, University of California, Davis, California 95616 (K.C., B.P., T.W., R.W.M.)
| | - Richard W. Michelmore
- Department of Plant and Soil Sciences (R.S.N., B.C.M.), and Delaware Biotechnology Institute (R.S.N., J.L.C., B.C.M.), University of Delaware, Newark, Delaware 19711; and
- UC Davis Genome Center, University of California, Davis, California 95616 (K.C., B.P., T.W., R.W.M.)
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28
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Rana RR, Zhang M, Spear AM, Atkins HS, Byrne B. Bacterial TIR-containing proteins and host innate immune system evasion. Med Microbiol Immunol 2012; 202:1-10. [PMID: 22772799 DOI: 10.1007/s00430-012-0253-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Accepted: 06/21/2012] [Indexed: 12/29/2022]
Abstract
The innate immune system provides the first line of host defence against invading pathogens. Key to upregulation of the innate immune response are Toll-like receptors (TLRs), which recognize pathogen-associated molecular patterns (PAMPs) and trigger a signaling pathway culminating in the production of inflammatory mediators. Central to this TLR signaling pathway are heterotypic protein-protein interactions mediated through Toll/interleukin-1 receptor (TIR) domains found in both the cytoplasmic regions of TLRs and adaptor proteins. Pathogenic bacteria have developed a range of ingenuous strategies to evade the host immune mechanisms. Recent work has identified a potentially novel evasion mechanism involving bacterial TIR domain proteins. Such domains have been identified in a wide range of pathogenic bacteria, and there is evidence to suggest that they interfere directly with the TLR signaling pathway and thus inhibit the activation of NF-κB. The individual TIR domains from the pathogenic bacteria Salmonella enterica serovar Enteritidis, Brucella sp, uropathogenic E. coli and Yersinia pestis have been analyzed in detail. The individual bacterial TIR domains from these pathogenic bacteria seem to differ in their modes of action and their roles in virulence. Here, we review the current state of knowledge on the possible roles and mechanisms of action of the bacterial TIR domains.
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Affiliation(s)
- Rohini R Rana
- Division of Molecular Biosciences, Imperial College London, South Kensington, London, UK
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29
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Active evasion of CTL mediated killing and low quality responding CD8+ T cells contribute to persistence of brucellosis. PLoS One 2012; 7:e34925. [PMID: 22558103 PMCID: PMC3338818 DOI: 10.1371/journal.pone.0034925] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 03/09/2012] [Indexed: 02/02/2023] Open
Abstract
Brucellosis is a common zoonotic disease that remains endemic in many parts of the world. Dissecting the host immune response during this disease provides insight as to why brucellosis is often difficult to resolve. We used a Brucella epitope specific in vivo killing assay to investigate the ability of CD8+ T cells to kill targets treated with purified pathogenic protein. Importantly, we found the pathogenic protein TcpB to be a novel effector of adaptive immune evasion by inhibiting CD8+ T cell killing of Brucella epitope specific target cells in mice. Further, BALB/c mice show active Brucella melitensis infection beyond one year, many with previously unreported focal infection of the urogenital area. A fraction of CD8+ T cells show a CD8+ Tmem phenotype of LFA-1hi, CD127hi, KLRG-1lo during the course of chronic brucellosis, while the CD8+ T cell pool as a whole had a very weak polyfunctional cytokine response with diminished co-expression of IFN-γ with TNFα and/or IL-2, a hallmark of exhaustion. When investigating the expression of these 3 cytokines individually, we observed significant IFN-γ expression at 90 and 180 days post-infection. TNFα expression did not significantly exceed or fall below background levels at any time. IL-2 expression did not significantly exceeded background, but, interestingly, did fall significantly below that of uninfected mice at 180 days post-infection. Brucella melitensis evades and blunts adaptive immunity during acute infection and our findings provide potential mechanisms for the deficit observed in responding CD8+ T cells during chronic brucellosis.
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30
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Deep sequencing-based expression transcriptional profiling changes during Brucella infection. Microb Pathog 2012; 52:267-77. [PMID: 22342430 DOI: 10.1016/j.micpath.2012.02.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2011] [Revised: 01/27/2012] [Accepted: 02/02/2012] [Indexed: 01/18/2023]
Abstract
Brucellosis is a worldwide zoonotic infectious disease that has significant economic effects on animal production and human health. The host macrophage -Brucella interaction is critical to the establishment of infections. Thus, the kinetic transcriptional profile of gene expression in macrophages infected with the Brucella melitensis strain 16M was investigated in the current study using a technology based on deep sequencing. The total RNA was extracted from macrophages 0, 4, and 24 h post-infection. Data analysis showed that in the gene ontology term, the expression of genes in the endoplasmic reticulum, lysosomes, as well as those involved in programmed cell death and apoptosis significantly changed during the first 24 h post-infection. Pathway enrichment analysis indicated that the genes in the apoptosis pathway, NOD-like receptor signaling pathway, Fc gamma R-mediated phagocytosis, lysosome pathway, p53 signaling pathway, and protein processing in the endoplasmic reticulum significantly changed during the first 24 h post-infection. The B-cell receptor and toll-like receptor signaling pathways were also significantly changed 24 h post-infection compared with those 4 h post-infection. The results of the current study can contribute to an improved understanding of the manner by which host cell responses may be manipulated to prevent Brucella infection.
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31
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Modulation of microtubule dynamics by a TIR domain protein from the intracellular pathogen Brucella melitensis. Biochem J 2011; 439:79-83. [PMID: 21692747 DOI: 10.1042/bj20110577] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
TIR (Toll/interleukin-1 receptor) domain-containing proteins play a crucial role in innate immunity in eukaryotes. Brucella is a highly infectious intracellular bacterium that encodes a TIR domain protein (TcpB) to subvert host innate immune responses to establish a beneficial niche for pathogenesis. TcpB inhibits NF-κB (nuclear factor κB) activation and pro-inflammatory cytokine secretions mediated by TLR (Toll-like receptor) 2 and TLR4. In the present study, we have demonstrated that TcpB modulates microtubule dynamics by acting as a stabilization factor. TcpB increased the rate of nucleation as well as the polymerization phases of microtubule formation in a similar manner to paclitaxel. TcpB could efficiently inhibit nocodazole- or cold-induced microtubule disassembly. Microtubule stabilization by TcpB is attributed to the BB-loop region of the TIR domain, and a point mutation affected the microtubule stabilization as well as the TLR-suppression properties of TcpB.
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32
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Martirosyan A, Moreno E, Gorvel JP. An evolutionary strategy for a stealthy intracellular Brucella pathogen. Immunol Rev 2011; 240:211-34. [PMID: 21349096 DOI: 10.1111/j.1600-065x.2010.00982.x] [Citation(s) in RCA: 162] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Brucella is an intracellular bacterial pathogen that causes abortion and infertility in mammals and leads to a debilitating febrile illness that can progress into a long lasting disease with severe complications in humans. Its virulence depends on survival and replication properties in host cells. In this review, we describe the stealthy strategy used by Brucella to escape recognition of the innate immunity and the means by which this bacterium evades intracellular destruction. We also discuss the development of adaptive immunity and its modulation during brucellosis that in course leads to chronic infections. Brucella has developed specific strategies to influence antigen presentation mediated by cells. There is increasing evidence that Brucella also modulates signaling events during host adaptive immune responses.
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Affiliation(s)
- Anna Martirosyan
- Faculté de Sciences de Luminy, Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Marseille, France
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Oliveira SC, de Almeida LA, Carvalho NB, Oliveira FS, Lacerda TLS. Update on the role of innate immune receptors during Brucella abortus infection. Vet Immunol Immunopathol 2011; 148:129-35. [PMID: 21700343 DOI: 10.1016/j.vetimm.2011.05.036] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Revised: 03/24/2011] [Accepted: 05/31/2011] [Indexed: 02/06/2023]
Abstract
The innate immune system constitutes an efficient defense mechanism against invading microbial pathogens. Recent studies have revealed the intracellular signaling cascades involved in the TLR-initiated immune response to Brucella spp. infection. However, there is a piece of the puzzle missing that is the role of non-TLR receptors in innate immunity. The involvement of TLR receptors in brucellosis has been investigated by different research groups. It was demonstrated that TLR2 clearly does not play any role in controlling Brucella abortus infection in vivo, whereas TLR9 has been shown to be required for clearance of this bacterium in infected mice. The participation of adaptor molecules, such as MyD88 and TRIF has also been discussed. Recently, we and others have reported the critical role of MyD88- and not TRIF-mediated signaling in dendritic cell maturation and in vivo resistance during B. abortus infection. However, the relationship between specific Brucella molecules and non-TLR receptors and signal transduction pathways needs to be better understood. It is now clear that the interaction between TLRs and recently identified cytosolic innate immune sensors is crucial for mounting effective immune responses. Finally, this review discusses the mechanisms used by Brucella to escape detection by the host innate immune system.
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Affiliation(s)
- Sérgio C Oliveira
- Department of Biochemistry and Immunology, Federal University of Minas Gerais, Av. Antonio Carlos 6627, Pampulha, Belo Horizonte, MG, Brazil.
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