1
|
Li J, Yuan N, Zhai Y, Wang M, Hao M, Liu X, Zhou D, Liu W, Jin Y, Wang A. Protein disulfide isomerase A4 binds to Brucella BtpB and mediates intracellular NAD +/NADH metabolism in RAW264.7 cells. Int Immunopharmacol 2024; 142:113046. [PMID: 39226825 DOI: 10.1016/j.intimp.2024.113046] [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: 07/06/2024] [Revised: 08/22/2024] [Accepted: 08/27/2024] [Indexed: 09/05/2024]
Abstract
The Toll/interleukin-1 receptor (TIR) signaling domain is distributed widely in mammalian Toll-like receptors and adaptors, plant nucleotide-binding leucine-rich repeat receptors, and specific bacterial virulence proteins. Proteins that possess TIR domain exhibit NADase activity which is distinct from the canonical signaling function of these domains. However, the effects of bacterial TIR domain proteins on host metabolic switches and the underlying mechanism of NADase activity in these proteins remain unclear. Here, we utilized Brucella TIR domain-containing type IV secretion system effector protein, BtpB, to explore the mechanism of NADase activity in host cells. We showed that using ectopic expression BtpB not only generates depletion of NAD+ but also loss of NADH and ATP in RAW264.7 macrophage cells. Moreover, immunoprecipitation-mass spectrometry, co-immunoprecipitation, and confocal microscope assays revealed that BtpB interacted with host protein disulfide isomerase A4 (PDIA4). The Brucella mutant strain deleted the gene for BtpB, significantly decreased PDIA4 expression. Furthermore, our data revealed that PDIA4 played an important role in regulating intracellular NAD+/NADH levels in macrophages, and PDIA4 overexpression restored the decline of intracellular NAD+ and NADH levels induced by Brucella BtpB. The results provide new insights into the metabolic regulatory activity of TIR domain proteins in the critical human and animal pathogen Brucella.
Collapse
Affiliation(s)
- Junmei Li
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China; Department of Veterinary Medicine, College of Coastal Agricultural Science, Guangdong Ocean University, Zhanjiang, 524088, China
| | - Ningqiu Yuan
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China
| | - Yunyi Zhai
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China
| | - Minghui Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China
| | - Mingyue Hao
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China
| | - Xiaofang Liu
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China
| | - Dong Zhou
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China
| | - Wei Liu
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China
| | - Yaping Jin
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling 712100, China
| | - Aihua Wang
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling 712100, China; Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China.
| |
Collapse
|
2
|
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.
Collapse
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.
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
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.
Collapse
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.
| |
Collapse
|
5
|
Achi SC, Karimilangi S, Lie D, Sayed IM, Das S. The WxxxE proteins in microbial pathogenesis. Crit Rev Microbiol 2023; 49:197-213. [PMID: 35287539 PMCID: PMC9737147 DOI: 10.1080/1040841x.2022.2046546] [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: 10/23/2021] [Revised: 02/10/2022] [Accepted: 02/19/2022] [Indexed: 12/14/2022]
Abstract
Effector proteins secreted by pathogens modulate various host cellular processes and help in bacterial pathogenesis. Some of these proteins, injected by enteric pathogens via Type Three Secretion System (T3SS) were grouped together based on a conserved signature motif (WxxxE) present in them. The presence of WxxxE motif is not limited to effectors released by enteric pathogens or the T3SS but has been detected in non-enteric pathogens, plant pathogens and in association with Type II and Type IV secretion systems. WxxxE effectors are involved in actin organization, inflammation regulation, vacuole or tubule formation, endolysosomal signalling regulation, tight junction disruption, and apoptosis. The WxxxE sequence has also been identified in TIR [Toll/interleukin-1 (IL-1) receptor] domains of bacteria and host. In the present review, we have focussed on the established and predicted functions of WxxxE effectors secreted by several pathogens, including enteric, non-enteric, and plant pathogens.
Collapse
Affiliation(s)
| | - Sareh Karimilangi
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Dominique Lie
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Ibrahim M. Sayed
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Soumita Das
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| |
Collapse
|
6
|
Manik MK, Shi Y, Li S, Zaydman MA, Damaraju N, Eastman S, Smith TG, Gu W, Masic V, Mosaiab T, Weagley JS, Hancock SJ, Vasquez E, Hartley-Tassell L, Kargios N, Maruta N, Lim BYJ, Burdett H, Landsberg MJ, Schembri MA, Prokes I, Song L, Grant M, DiAntonio A, Nanson JD, Guo M, Milbrandt J, Ve T, Kobe B. Cyclic ADP ribose isomers: Production, chemical structures, and immune signaling. Science 2022; 377:eadc8969. [PMID: 36048923 DOI: 10.1126/science.adc8969] [Citation(s) in RCA: 59] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Cyclic adenosine diphosphate (ADP)-ribose (cADPR) isomers are signaling molecules produced by bacterial and plant Toll/interleukin-1 receptor (TIR) domains via nicotinamide adenine dinucleotide (oxidized form) (NAD+) hydrolysis. We show that v-cADPR (2'cADPR) and v2-cADPR (3'cADPR) isomers are cyclized by O-glycosidic bond formation between the ribose moieties in ADPR. Structures of 2'cADPR-producing TIR domains reveal conformational changes that lead to an active assembly that resembles those of Toll-like receptor adaptor TIR domains. Mutagenesis reveals a conserved tryptophan that is essential for cyclization. We show that 3'cADPR is an activator of ThsA effector proteins from the bacterial antiphage defense system termed Thoeris and a suppressor of plant immunity when produced by the effector HopAM1. Collectively, our results reveal the molecular basis of cADPR isomer production and establish 3'cADPR in bacteria as an antiviral and plant immunity-suppressing signaling molecule.
Collapse
Affiliation(s)
- Mohammad K Manik
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Yun Shi
- Institute for Glycomics, Griffith University, Southport, QLD 4222, Australia
| | - Sulin Li
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Mark A Zaydman
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, St. Louis, MO 63100, USA
| | - Neha Damaraju
- Department of Developmental Biology, Washington University School of Medicine in St. Louis, St. Louis, MO 63100, USA
- Department of Genetics, Washington University School of Medicine in St. Louis, St. Louis, MO 63100, USA
| | - Samuel Eastman
- Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
| | - Thomas G Smith
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - Weixi Gu
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Veronika Masic
- Institute for Glycomics, Griffith University, Southport, QLD 4222, Australia
| | - Tamim Mosaiab
- Institute for Glycomics, Griffith University, Southport, QLD 4222, Australia
| | - James S Weagley
- Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Steven J Hancock
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Eduardo Vasquez
- Institute for Glycomics, Griffith University, Southport, QLD 4222, Australia
| | | | - Nestoras Kargios
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - Natsumi Maruta
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Bryan Y J Lim
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Hayden Burdett
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Michael J Landsberg
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Mark A Schembri
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Ivan Prokes
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK
| | - Lijiang Song
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK
| | - Murray Grant
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - Aaron DiAntonio
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, St. Louis, MO 63100, USA
- Department of Developmental Biology, Washington University School of Medicine in St. Louis, St. Louis, MO 63100, USA
| | - Jeffrey D Nanson
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Ming Guo
- Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
| | - Jeffrey Milbrandt
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, St. Louis, MO 63100, USA
| | - Thomas Ve
- Institute for Glycomics, Griffith University, Southport, QLD 4222, Australia
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD 4072, Australia
- The University of Queensland, Institute for Molecular Bioscience, Brisbane, QLD 4072, Australia
| |
Collapse
|
7
|
Mazumdar V, Joshi K, Nandi BR, Namani S, Gupta VK, Radhakrishnan G. 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 PMCID: PMC9119127 DOI: 10.1128/iai.00060-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 03/14/2022] [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.
Collapse
Affiliation(s)
- Varadendra Mazumdar
- Laboratory of Immunology and Microbial Pathogenesis, National Institute of Animal Biotechnology (NIAB), Hyderabad, Telangana, India
- Regional Centre for Biotechnology (RCB), Faridabad, Haryana, India
| | - Kiranmai Joshi
- Laboratory of Immunology and Microbial Pathogenesis, National Institute of Animal Biotechnology (NIAB), Hyderabad, Telangana, India
- Regional Centre for Biotechnology (RCB), Faridabad, Haryana, 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, Haryana, India
| | - Swapna Namani
- Laboratory of Immunology and Microbial Pathogenesis, National Institute of Animal Biotechnology (NIAB), Hyderabad, Telangana, India
| | - Vivek Kumar Gupta
- ICAR-Indian Veterinary Research Institute (ICAR-IVRI), Izatnagar, Bareilly, India
| | - Girish Radhakrishnan
- Laboratory of Immunology and Microbial Pathogenesis, National Institute of Animal Biotechnology (NIAB), Hyderabad, Telangana, India
| |
Collapse
|
8
|
Antibiogram Screening and Detection of Virulence-Associated Genes in Brucella Species Acquired from Cattle in South Africa's Eastern Cape Province. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19052813. [PMID: 35270507 PMCID: PMC8909984 DOI: 10.3390/ijerph19052813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 02/02/2022] [Accepted: 02/07/2022] [Indexed: 12/04/2022]
Abstract
Brucellosis is a widespread zoonotic illness, and it poses serious public health and economic risks. The purpose of this investigation is to look at the antimicrobial susceptibility of unpasteurized milk, blood, and lymph node specimens from cattle, goats, and sheep, as well as to identify virulence-associated genes. In this investigation, a total of 123 isolates were examined. The activity of 15 antimicrobials against Brucella pathogens were assessed using the Kirby−Bauer disk diffusion technique. Nine virulence factors were detected with polymerase chain reaction analysis. Five antibiotics were 100% effective against Brucella isolates. A high level of resistance (100%) was documented with streptomycin, penicillin, and seven more antibiotics. Doxycycline resistance was found in 12% of goat isolates, and tetracycline resistance was found in 21% and 44% of goat and sheep isolates, respectively. Multiple antibiotic resistance (MAR) index >0.2 was found in 38.2% (47/123) of Brucella isolates. VecC and BetB, two B. abortus genes, were confirmed to be comparable. The findings of this study suggests that Brucella spp. are reservoirs of antibiotic resistance in the Eastern Cape Province. As such, they represent a potential pool of antibiotic genes that might be transferred to other pathogens in the community, and thus continue to pose a healthcare hazard.
Collapse
|
9
|
Sayed IM, Ibeawuchi SR, Lie D, Anandachar MS, Pranadinata R, Raffatellu M, Das S. The interaction of enteric bacterial effectors with the host engulfment pathway control innate immune responses. Gut Microbes 2022; 13:1991776. [PMID: 34719317 PMCID: PMC8565811 DOI: 10.1080/19490976.2021.1991776] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Host engulfment protein ELMO1 generates intestinal inflammation following internalization of enteric bacteria. In Shigella, bacterial effector IpgB1 interacts with ELMO1 and promotes bacterial invasion. IpgB1 belongs to the WxxxE effector family, a motif found in several effectors of enteric pathogens. Here, we have studied the role of WxxxE effectors, with emphasis on Salmonella SifA and whether it interacts with ELMO1 to regulate inflammation. In-silico-analysis of WxxxE effectors was performed using BLAST search and Clustal W program. The interaction of ELMO1 with SifA was assessed by GST pulldown assay and co-immunoprecipitation. ELMO1 knockout mice, and ELMO1-depleted murine macrophage J774 cell lines were challenged with WT and SifA mutant Salmonella. Bacterial effectors containing the WxxxE motif were transfected in WT and ELMO1-depleted J774 cells to assess the inflammatory cytokines. ELMO1 generates differential pro-inflammatory cytokines between pathogenic and nonpathogenic bacteria. WxxxE motif is present in pathogens and in the TIR domain of host proteins. The C-terminal part of ELMO1 interacts with SifA where WxxxE motif is important for interaction. ELMO1-SifA interaction affects bacterial colonization, dissemination, and inflammatory cytokines in vivo. Moreover, ELMO1-SifA interaction increases TNF-α and IL-6 production from the macrophage cell line and is associated with enhanced Rac1 activity. ELMO1 also interacts with WxxxE effectors IpgB1, IpgB2, and Map and induces inflammation after challenge with microbes or microbial ligands. ELMO1 generates a differential response through interaction with the WxxxE motif, which is absent in commensals. ELMO1-WxxxE interaction plays a role in bacterial pathogenesis and induction of inflammatory response.
Collapse
Affiliation(s)
- Ibrahim M Sayed
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | | | - Dominique Lie
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | | | - Rama Pranadinata
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Manuela Raffatellu
- Department of Pediatrics, Division of Host-Microbe Systems and Therapeutics, University of California San Diego, LA Jolla, CA, USA,Center for Mucosal Immunology, Chiba University-UC San Diego, La Jolla, CAUSA
| | - Soumita Das
- Department of Pathology, University of California San Diego, La Jolla, CA, USA,CONTACT Soumita Das Department of Pathology, University of California, San Diego, 9500 Gilman Drive, Mc 0644, George Palade Laboratory, Office Rm 256, San Diego, Ca, 92093-0644, USA
| |
Collapse
|
10
|
Roussin M, Salcedo SP. NAD+-targeting by bacteria: an emerging weapon in pathogenesis. FEMS Microbiol Rev 2021; 45:6315328. [PMID: 34223888 DOI: 10.1093/femsre/fuab037] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 07/01/2021] [Indexed: 11/14/2022] Open
Abstract
Nicotinamide adenine dinucleotide (NAD+) is a major cofactor in redox reactions in all lifeforms. A stable level of NAD+ is vital to ensure cellular homeostasis. Some pathogens can modulate NAD+ metabolism to their advantage and even utilize or cleave NAD+ from the host using specialized effectors known as ADP-ribosyltransferase toxins and NADases, leading to energy store depletion, immune evasion, or even cell death. This review explores recent advances in the field of bacterial NAD+-targeting toxins, highlighting the relevance of NAD+ modulation as an emerging pathogenesis strategy. In addition, we discuss the role of specific NAD+-targeting toxins in niche colonization and bacterial lifestyle as components of Toxin/Antitoxin systems and key players in inter-bacterial competition. Understanding the mechanisms of toxicity, regulation, and secretion of these toxins will provide interesting leads in the search for new antimicrobial treatments in the fight against infectious diseases.
Collapse
Affiliation(s)
- Morgane Roussin
- Laboratory of Molecular Microbiology and Structural Biochemistry, Centre National de la Recherche Scientifique UMR5086, Université de Lyon, Lyon, France
| | - Suzana P Salcedo
- Laboratory of Molecular Microbiology and Structural Biochemistry, Centre National de la Recherche Scientifique UMR5086, Université de Lyon, Lyon, France
| |
Collapse
|
11
|
Whole-Genome Sequencing for Tracing the Genetic Diversity of Brucella abortus and Brucella melitensis Isolated from Livestock in Egypt. Pathogens 2021; 10:pathogens10060759. [PMID: 34208761 PMCID: PMC8235727 DOI: 10.3390/pathogens10060759] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 06/07/2021] [Accepted: 06/11/2021] [Indexed: 02/03/2023] Open
Abstract
Brucellosis is a highly contagious zoonosis that occurs worldwide. Whole-genome sequencing (WGS) has become a widely accepted molecular typing method for outbreak tracing and genomic epidemiology of brucellosis. Twenty-nine Brucella spp. (eight B. abortus biovar 1 and 21 B. melitensis biovar 3) were isolated from lymph nodes, milk, and fetal abomasal contents of infected cattle, buffaloes, sheep, and goats originating from nine districts in Egypt. The isolates were identified by microbiological methods and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Differentiation and genotyping were confirmed using multiplex PCR. Illumina MiSeq® was used to sequence the 29 Brucella isolates. Using MLST typing, ST11 and ST1 were identified among B. melitensis and B. abortus, respectively. Brucella abortus and B. melitensis isolates were divided into two main clusters (clusters 1 and 2) containing two and nine distinct genotypes by core-genome SNP analysis, respectively. The genotypes were irregularly distributed over time and space in the study area. Both Egyptian B. abortus and B. melitensis isolates proved to be genomically unique upon comparison with publicly available sequencing from strains of neighboring Mediterranean, African, and Asian countries. The antimicrobial resistance mechanism caused by mutations in rpoB, gyrA, and gyrB genes associated with rifampicin and ciprofloxacin resistance were identified. To the best of our knowledge, this is the first study investigating the epidemiology of Brucella isolates from livestock belonging to different localities in Egypt based on whole genome analysis.
Collapse
|
12
|
Mak H, Thurston TLM. Interesting Biochemistries in the Structure and Function of Bacterial Effectors. Front Cell Infect Microbiol 2021; 11:608860. [PMID: 33718265 PMCID: PMC7943720 DOI: 10.3389/fcimb.2021.608860] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 01/13/2021] [Indexed: 11/13/2022] Open
Abstract
Bacterial effector proteins, delivered into host cells by specialized multiprotein secretion systems, are a key mediator of bacterial pathogenesis. Following delivery, they modulate a range of host cellular processes and functions. Strong selective pressures have resulted in bacterial effectors evolving unique structures that can mimic host protein biochemical activity or enable novel and distinct biochemistries. Despite the protein structure-function paradigm, effectors from different bacterial species that share biochemical activities, such as the conjugation of ubiquitin to a substrate, do not necessarily share structural or sequence homology to each other or the eukaryotic proteins that carry out the same function. Furthermore, some bacterial effectors have evolved structural variations to known protein folds which enable different or additional biochemical and physiological functions. Despite the overall low occurrence of intrinsically disordered proteins or regions in prokaryotic proteomes compared to eukaryotes proteomes, bacterial effectors appear to have adopted intrinsically disordered regions that mimic the disordered regions of eukaryotic signaling proteins. In this review, we explore examples of the diverse biochemical properties found in bacterial effectors that enable effector-mediated interference of eukaryotic signaling pathways and ultimately support pathogenesis. Despite challenges in the structural and functional characterisation of effectors, recent progress has been made in understanding the often unusual and fascinating ways in which these virulence factors promote pathogenesis. Nevertheless, continued work is essential to reveal the array of remarkable activities displayed by effectors.
Collapse
Affiliation(s)
| | - Teresa L. M. Thurston
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| |
Collapse
|
13
|
Roop RM, Barton IS, Hopersberger D, Martin DW. Uncovering the Hidden Credentials of Brucella Virulence. Microbiol Mol Biol Rev 2021; 85:e00021-19. [PMID: 33568459 PMCID: PMC8549849 DOI: 10.1128/mmbr.00021-19] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Bacteria in the genus Brucella are important human and veterinary pathogens. The abortion and infertility they cause in food animals produce economic hardships in areas where the disease has not been controlled, and human brucellosis is one of the world's most common zoonoses. Brucella strains have also been isolated from wildlife, but we know much less about the pathobiology and epidemiology of these infections than we do about brucellosis in domestic animals. The brucellae maintain predominantly an intracellular lifestyle in their mammalian hosts, and their ability to subvert the host immune response and survive and replicate in macrophages and placental trophoblasts underlies their success as pathogens. We are just beginning to understand how these bacteria evolved from a progenitor alphaproteobacterium with an environmental niche and diverged to become highly host-adapted and host-specific pathogens. Two important virulence determinants played critical roles in this evolution: (i) a type IV secretion system that secretes effector molecules into the host cell cytoplasm that direct the intracellular trafficking of the brucellae and modulate host immune responses and (ii) a lipopolysaccharide moiety which poorly stimulates host inflammatory responses. This review highlights what we presently know about how these and other virulence determinants contribute to Brucella pathogenesis. Gaining a better understanding of how the brucellae produce disease will provide us with information that can be used to design better strategies for preventing brucellosis in animals and for preventing and treating this disease in humans.
Collapse
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
| |
Collapse
|
14
|
The TIR-domain containing effectors BtpA and BtpB from Brucella abortus impact NAD metabolism. PLoS Pathog 2020; 16:e1007979. [PMID: 32298382 PMCID: PMC7188309 DOI: 10.1371/journal.ppat.1007979] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 04/28/2020] [Accepted: 03/26/2020] [Indexed: 12/20/2022] Open
Abstract
Brucella species are facultative intracellular Gram-negative bacteria relevant to animal and human health. Their ability to establish an intracellular niche and subvert host cell pathways to their advantage depends on the delivery of bacterial effector proteins through a type IV secretion system. Brucella Toll/Interleukin-1 Receptor (TIR)-domain-containing proteins BtpA (also known as TcpB) and BtpB are among such effectors. Although divergent in primary sequence, they interfere with Toll-like receptor (TLR) signaling to inhibit the innate immune responses. However, the molecular mechanisms implicated still remain unclear. To gain insight into the functions of BtpA and BtpB, we expressed them in the budding yeast Saccharomyces cerevisiae as a eukaryotic cell model. We found that both effectors were cytotoxic and that their respective TIR domains were necessary and sufficient for yeast growth inhibition. Growth arrest was concomitant with actin depolymerization, endocytic block and a general decrease in kinase activity in the cell, suggesting a failure in energetic metabolism. Indeed, levels of ATP and NAD+ were low in yeast cells expressing BtpA and BtpB TIR domains, consistent with the recently described enzymatic activity of some TIR domains as NAD+ hydrolases. In human epithelial cells, both BtpA and BtpB expression reduced intracellular total NAD levels. In infected cells, both BtpA and BtpB contributed to reduction of total NAD, indicating that their NAD+ hydrolase functions are active intracellularly during infection. Overall, combining the yeast model together with mammalian cells and infection studies our results show that BtpA and BtpB modulate energy metabolism in host cells through NAD+ hydrolysis, assigning a novel role for these TIR domain-containing effectors in Brucella pathogenesis. Brucella is a genus of zoonotic bacteria that cause severe disease in a variety of mammals, ranging from farm animals (as bovines, swine and ovine) to marine mammals. Transmission to humans, often by ingestion of non-treated dairy products, leads to serious systemic infection. Brucella abortus invades host cells and replicates intracellularly. Such behavior relies on the injection of bacterial proteins into the host cytoplasm via specialized secretion systems. Our work focuses on the study of two of these factors, BtpA and BtpB, previously described to contain Toll/Interleukin-1 Receptor (TIR)-domains that modulate innate immunity. We use here two biological models: the yeast Saccharomyces cerevisiae and human cell lines. We found that the TIR domains of both Brucella proteins were necessary and sufficient to collapse energy metabolism in yeast by depleting ATP and NAD+. This result was translatable to higher cells and consistent with the recently described NADase activity of some TIR domains both in mammalian and bacterial proteins. Importantly, we demonstrate that Brucella down-regulates total NAD levels in host cells by using both BtpA and BtpB effectors. Our results show that NAD+ is targeted by Brucella during infection, which may constitute a novel mechanism for its pathogenicity.
Collapse
|
15
|
Hostile Takeover: Hijacking of Endoplasmic Reticulum Function by T4SS and T3SS Effectors Creates a Niche for Intracellular Pathogens. Microbiol Spectr 2020; 7. [PMID: 31198132 DOI: 10.1128/microbiolspec.psib-0027-2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
After entering a cell, intracellular pathogens must evade destruction and generate a niche for intracellular replication. A strategy shared by multiple intracellular pathogens is the deployment of type III secretion system (T3SS)- and type IV secretion system (T4SS)-injected proteins (effectors) that subvert cellular functions. A subset of these effectors targets activities of the host cell's endoplasmic reticulum (ER). Effectors are now appreciated to interfere with the ER in multiple ways, including capture of secretory vesicles, tethering of pathogen vacuoles to the ER, and manipulation of ER-based autophagy initiation and the unfolded-protein response. These strategies enable pathogens to generate a niche with access to cellular nutrients and to evade the host cell's defenses.
Collapse
|
16
|
Shirey KA, Lai W, Brown LJ, Blanco JCG, Beadenkopf R, Wang Y, Vogel SN, Snyder GA. Select targeting of intracellular Toll-interleukin-1 receptor resistance domains for protection against influenza-induced disease. Innate Immun 2020; 26:26-34. [PMID: 31955622 PMCID: PMC6974880 DOI: 10.1177/1753425919846281] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 03/01/2019] [Accepted: 03/22/2019] [Indexed: 12/20/2022] Open
Abstract
TLRs are a family of PRRs that respond to PAMPs or host-derived Danger-Associated Molecular Patterns (DAMPs) to initiate host inflammation and immune responses. TLR dimerization and recruitment of adapter molecules is critical for intracellular signaling and is mediated through intracellular Toll-Interleukin 1 Receptor Resistance (TIR) domain interactions. Human TIR domains, including reported structures of TIR1, TIR2, TIR6, TIR10, TIRAP, and MyD88, contain Cysteine (Cys) interactions or modifications that are disproportionally at, or near, reported biological TIR interfaces, or in close proximity to functionally important regions. Therefore, we hypothesized that intracellular TIR Cys regulation may have greater functional importance than previously appreciated. Expression of mutant TLR4-C747S or treatment of TLR4 reporter cells with a small molecule, Cys-binding inhibitor of TLR4, TAK-242, abrogated LPS signaling in vitro . Using TAK-242, mice were protected from lethal influenza challenge as previously reported for extracellular TLR4 antagonists. Molecular modeling and sequence analysis of the region surrounding TLR4-Cys747 indicate conservation of a WxxxE motif identified among bacterial and NAD+-consuming TIRs, as well as within the TIRs domains of surface TLRs 1, 2, 4, 6, and 10. Together, these data support the hypothesis that critical Cys within the TIR domain are essential for TLR4 functionality.
Collapse
Affiliation(s)
- Kari Ann Shirey
- Department of Microbiology and Immunology, University of
Maryland School of Medicine, USA
| | - Wendy Lai
- Department of Microbiology and Immunology, University of
Maryland School of Medicine, USA
| | - Lindsey J Brown
- Institute of Human Virology, Department of Medicine, University
of Maryland School of Medicine, USA
| | | | - Robert Beadenkopf
- Institute of Human Virology, Department of Medicine, University
of Maryland School of Medicine, USA
| | - Yajing Wang
- Institute of Human Virology, Department of Medicine, University
of Maryland School of Medicine, USA
- China Pharmaceutical University, Nanjing, P.R. China
| | - Stefanie N Vogel
- Department of Microbiology and Immunology, University of
Maryland School of Medicine, USA
| | - Greg A Snyder
- Department of Microbiology and Immunology, University of
Maryland School of Medicine, USA
- Institute of Human Virology, Department of Medicine, University
of Maryland School of Medicine, USA
| |
Collapse
|
17
|
Guzmán-Verri C, Suárez-Esquivel M, Ruíz-Villalobos N, Zygmunt MS, Gonnet M, Campos E, Víquez-Ruiz E, Chacón-Díaz C, Aragón-Aranda B, Conde-Álvarez R, Moriyón I, Blasco JM, Muñoz PM, Baker KS, Thomson NR, Cloeckaert A, Moreno E. Genetic and Phenotypic Characterization of the Etiological Agent of Canine Orchiepididymitis Smooth Brucella sp. BCCN84.3. Front Vet Sci 2019; 6:175. [PMID: 31231665 PMCID: PMC6568212 DOI: 10.3389/fvets.2019.00175] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Accepted: 05/20/2019] [Indexed: 01/14/2023] Open
Abstract
Members of the genus Brucella cluster in two phylogenetic groups: classical and non-classical species. The former group is composed of Brucella species that cause disease in mammals, including humans. A Brucella species, labeled as Brucella sp. BCCN84.3, was isolated from the testes of a Saint Bernard dog suffering orchiepididymitis, in Costa Rica. Following standard microbiological methods, the bacterium was first defined as “Brucella melitensis biovar 2.” Further molecular typing, identified the strain as an atypical “Brucella suis.” Distinctive Brucella sp. BCCN84.3 markers, absent in other Brucella species and strains, were revealed by fatty acid methyl ester analysis, high resolution melting PCR and omp25 and omp2a/omp2b gene diversity. Analysis of multiple loci variable number of tandem repeats and whole genome sequencing demonstrated that this isolate was different from the currently described Brucella species. The smooth Brucella sp. BCCN84.3 clusters together with the classical Brucella clade and displays all the genes required for virulence. Brucella sp. BCCN84.3 is a species nova taxonomical entity displaying pathogenicity; therefore, relevant for differential diagnoses in the context of brucellosis. Considering the debate on the Brucella species concept, there is a need to describe the extant taxonomical entities of these pathogens in order to understand the dispersion and evolution.
Collapse
Affiliation(s)
- Caterina Guzmán-Verri
- Programa de Investigación en Enfermedades Tropicales (PIET), Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica.,Facultad de Microbiología, Centro de Investigación en Enfermedades Tropicales, Universidad de Costa Rica, San José, Costa Rica
| | - Marcela Suárez-Esquivel
- Programa de Investigación en Enfermedades Tropicales (PIET), Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
| | - Nazareth Ruíz-Villalobos
- Programa de Investigación en Enfermedades Tropicales (PIET), Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
| | - Michel S Zygmunt
- ISP, INRA, Université François Rabelais de Tours, Nouzilly, France
| | - Mathieu Gonnet
- ISP, INRA, Université François Rabelais de Tours, Nouzilly, France
| | - Elena Campos
- Centro Nacional de Referencia en Bacteriología, Instituto Costarricense de Investigación y Enseñanza en Nutrición y Salud (INCIENSA), Cartago, Costa Rica
| | - Eunice Víquez-Ruiz
- Programa de Investigación en Enfermedades Tropicales (PIET), Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
| | - Carlos Chacón-Díaz
- Facultad de Microbiología, Centro de Investigación en Enfermedades Tropicales, Universidad de Costa Rica, San José, Costa Rica
| | - Beatriz Aragón-Aranda
- IDISNA and Departamento de Microbiología y Parasitología, Instituto de Salud Tropical, Universidad de Navarra, Pamplona, Spain
| | - Raquel Conde-Álvarez
- IDISNA and Departamento de Microbiología y Parasitología, Instituto de Salud Tropical, Universidad de Navarra, Pamplona, Spain
| | - Ignacio Moriyón
- IDISNA and Departamento de Microbiología y Parasitología, Instituto de Salud Tropical, Universidad de Navarra, Pamplona, Spain
| | - José María Blasco
- Unidad de Producción y Sanidad Animal, Instituto Agroalimentario de Aragón-IA2, CITA-Universidad de Zaragoza, Zaragoza, Spain
| | - Pilar M Muñoz
- Unidad de Producción y Sanidad Animal, Instituto Agroalimentario de Aragón-IA2, CITA-Universidad de Zaragoza, Zaragoza, Spain
| | - Kate S Baker
- Pathogen Genomics, Wellcome Trust Sanger Institute, Hinxton, United Kingdom.,Institute for Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Nicholas R Thomson
- Pathogen Genomics, Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Axel Cloeckaert
- ISP, INRA, Université François Rabelais de Tours, Nouzilly, France
| | - Edgardo Moreno
- Programa de Investigación en Enfermedades Tropicales (PIET), Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
| |
Collapse
|
18
|
Dehio C, Tsolis RM. Type IV Effector Secretion and Subversion of Host Functions by Bartonella and Brucella Species. Curr Top Microbiol Immunol 2019. [PMID: 29536363 DOI: 10.1007/978-3-319-75241-9_11] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2023]
Abstract
Bartonella and Brucella species comprise closely related genera of the order Rhizobiales within the class α-proteobacteria. Both groups of bacteria are mammalian pathogens with a facultative intracellular lifestyle and are capable of causing chronic infections, but members of each genus have evolved broadly different infection and transmission strategies. While Brucella spp. transmit in general via the reproductive tract in their natural hosts, the Bartonella spp. have evolved to transmit via arthropod vectors. However, a shared feature of both groups of pathogens is their reliance on type IV secretion systems (T4SSs) to interact with cells in their mammalian hosts. The genomes of Bartonella spp. encode three types of T4SS, Trw, Vbh/TraG, and VirB/VirD4, whereas those of Brucella spp. uniformly contain a single T4SS of the VirB type. The VirB systems of Bartonella and Brucella are associated with distinct groups of effector proteins that collectively mediate interactions with host cells. This chapter discusses recent findings on the role of T4SS in the biology of Bartonella spp. and Brucella spp. with emphasis on effector repertoires, on recent advances in our understanding of their evolution, how individual effectors function at the molecular level, and on the consequences of these interactions for cellular and immune responses in the host.
Collapse
Affiliation(s)
| | - Renée M Tsolis
- Medical Microbiology and Immunology, University of California at Davis, Davis, CA, 95616, USA.
| |
Collapse
|
19
|
Enterococcus faecium TIR-Domain Genes Are Part of a Gene Cluster Which Promotes Bacterial Survival in Blood. Int J Microbiol 2019; 2018:1435820. [PMID: 30631364 PMCID: PMC6304867 DOI: 10.1155/2018/1435820] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 10/14/2018] [Indexed: 11/29/2022] Open
Abstract
Enterococcus faecium has undergone a transition to a multidrug-resistant nosocomial pathogen. The population structure of E. faecium is characterized by a sharp distinction of clades, where the hospital-adapted lineage is primarily responsible for bacteremia. So far, factors that were identified in hospital-adapted strains and that promoted pathogenesis of nosocomial E. faecium mainly play a role in adherence and biofilm production, while less is known about factors contributing to survival in blood. This study identified a gene cluster, which includes genes encoding bacterial Toll/interleukin-1 receptor- (TIR-) domain-containing proteins (TirEs). The cluster was found to be unique to nosocomial strains and to be located on a putative mobile genetic element of phage origin. The three genes within the cluster appeared to be expressed as an operon. Expression was detected in bacterial culture media and in the presence of human blood. TirEs are released into the bacterial supernatant, and TirE2 is associated with membrane vesicles. Furthermore, the tirE-gene cluster promotes bacterial proliferation in human blood, indicating that TirE may contribute to the pathogenesis of bacteremia.
Collapse
|
20
|
Nanson JD, Rahaman MH, Ve T, Kobe B. Regulation of signaling by cooperative assembly formation in mammalian innate immunity signalosomes by molecular mimics. Semin Cell Dev Biol 2018; 99:96-114. [PMID: 29738879 DOI: 10.1016/j.semcdb.2018.05.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 03/18/2018] [Accepted: 05/04/2018] [Indexed: 12/16/2022]
Abstract
Innate immunity pathways constitute the first line of defense against infections and cellular damage. An emerging concept in these pathways is that signaling involves the formation of finite (e.g. rings in NLRs) or open-ended higher-order assemblies (e.g. filamentous assemblies by members of the death-fold family and TIR domains). This signaling by cooperative assembly formation (SCAF) mechanism allows rapid and strongly amplified responses to minute amounts of stimulus. While the characterization of the molecular mechanisms of SCAF has seen rapid progress, little is known about its regulation. One emerging theme involves proteins produced both in host cells and by pathogens that appear to mimic the signaling components. Recently characterized examples involve the capping of the filamentous assemblies formed by caspase-1 CARDs by the CARD-only protein INCA, and those formed by caspase-8 by the DED-containing protein MC159. By contrast, the CARD-only protein ICEBERG and the DED-containing protein cFLIP incorporate into signaling filaments and presumably interfere with proximity based activation of caspases. We review selected examples of SCAF in innate immunity pathways and focus on the current knowledge on signaling component mimics produced by mammalian and pathogen cells and what is known about their mechanisms of action.
Collapse
Affiliation(s)
- Jeffrey D Nanson
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Md Habibur Rahaman
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Thomas Ve
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD, 4072, Australia; Institute for Glycomics, Griffith University, Southport, QLD, 4222, Australia
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD, 4072, Australia.
| |
Collapse
|
21
|
Zhang Z, Luo Z, Min W, Zhang L, Wu Y, Hu X. An anti-cancer WxxxE-containing azurin polypeptide inhibits Rac1-dependent STAT3 and ERK/GSK-3β signaling in breast cancer cells. Oncotarget 2018; 8:43091-43103. [PMID: 28549350 PMCID: PMC5522130 DOI: 10.18632/oncotarget.17759] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 03/28/2017] [Indexed: 12/15/2022] Open
Abstract
In our previous study, we characterized a mycoplasmal small GTPase-like polypeptide of 240 amino acids that possesses an N-terminal WVLGE sequence. The N-terminal WVLGE sequence promotes activation of Rac1 and subsequent host cancer cell proliferation. To investigate the function of the WxxxE motif in the interaction with Rac1 and host tumor progression, we synthesized a 35-amino acid WVLGE-containing polypeptide derived from a cell-penetrating peptide derived from the azurin protein. We verified that the WVLGE-containing polypeptide targeted MCF-7 cells rather than MCF-10A cells. However, the WVLGE-containing polypeptide inhibited activation of Rac1 and induced cellular phenotypes that resulted from inhibition of Rac1. In addition, the WVLGE-containing polypeptide down-regulated phosphorylation of the STAT3 and ERK/GSK-3β signaling pathways, and this effect was abolished by either stimulation or inhibition of Rac1 activity. We also found that the WVLGE-containing polypeptide has a Rac1-dependent potential to suppress breast cancer growth in vitro and in vivo. We suggest that by acting as a Rac1 inhibitor, this novel polypeptide may be useful for the treatment of breast cancer.
Collapse
Affiliation(s)
- Zhe Zhang
- Department of Breast and Thyroid Surgery, Division of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Zhiyong Luo
- Department of Breast and Thyroid Surgery, Division of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Wenpu Min
- The First People's Hospital of Jingzhou, Jingzhou, People's Republic of China
| | - Lin Zhang
- Department of Breast and Thyroid Surgery, Division of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Yaqun Wu
- Department of Breast and Thyroid Surgery, Division of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Xiaopeng Hu
- Department of Breast and Thyroid Surgery, Division of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| |
Collapse
|
22
|
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.
Collapse
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
| |
Collapse
|
23
|
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
| |
Collapse
|
24
|
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.
Collapse
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.
| |
Collapse
|
25
|
The TIR Homologue Lies near Resistance Genes in Staphylococcus aureus, Coupling Modulation of Virulence and Antimicrobial Susceptibility. PLoS Pathog 2017; 13:e1006092. [PMID: 28060920 PMCID: PMC5218399 DOI: 10.1371/journal.ppat.1006092] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 11/28/2016] [Indexed: 01/04/2023] Open
Abstract
Toll/interleukin-1 receptor (TIR) domains in Toll-like receptors are essential for initiating and propagating the eukaryotic innate immune signaling cascade. Here, we investigate TirS, a Staphylococcus aureus TIR mimic that is part of a novel bacterial invasion mechanism. Its ectopic expression in eukaryotic cells inhibited TLR signaling, downregulating the NF-kB pathway through inhibition of TLR2, TLR4, TLR5, and TLR9. Skin lesions induced by the S. aureus knockout tirS mutant increased in a mouse model compared with wild-type and restored strains even though the tirS-mutant and wild-type strains did not differ in bacterial load. TirS also was associated with lower neutrophil and macrophage activity, confirming a central role in virulence attenuation through local inflammatory responses. TirS invariably localizes within the staphylococcal chromosomal cassettes (SCC) containing the fusC gene for fusidic acid resistance but not always carrying the mecA gene. Of note, sub-inhibitory concentration of fusidic acid increased tirS expression. Epidemiological studies identified no link between this effector and clinical presentation but showed a selective advantage with a SCCmec element with SCC fusC/tirS. Thus, two key traits determining the success and spread of bacterial infections are linked. Pathogenic microbes have evolved elaborate strategies to manipulate host defenses to establish and spread in the host population. One such mechanism involves disruption of the immune signaling cascade orchestrated by the Toll-like receptors (TLRs), which sense microbial attack. TLR signaling elicits a proinflammatory response that controls immune cell recruitment to infected tissues. Here, we show that Staphylococcus aureus, an opportunistic human pathogen, expresses a host defense–like protein, TirS, that actively perturbs the initial TLR activation stage. Results with isolated human cells and mouse models show that TirS is a broad innate immune inhibitor of TLR-dependent signaling and modulates bacterial virulence, attenuating local inflammation. Moreover, the tirS gene lies near antimicrobial resistance genes for an antibiotic that enhances TirS production, shifting the balance to favor the pathogen and promote disease. Understanding mechanisms by which S. aureus modulates the immune response may lead to novel approaches for preventing and treating infection.
Collapse
|
26
|
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.
Collapse
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)
| |
Collapse
|