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Yao X, Rudensky E, Martin PK, Miller BM, Vargas I, Zwack EE, Lacey KA, He Z, Furtado GC, Lira SA, Torres VJ, Shopsin B, Cadwell K. Heterozygosity for Crohn's disease risk allele of ATG16L1 promotes unique protein interactions and protects against bacterial infection. Immunity 2025:S1074-7613(25)00186-4. [PMID: 40373771 DOI: 10.1016/j.immuni.2025.04.023] [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: 03/08/2024] [Revised: 11/25/2024] [Accepted: 04/17/2025] [Indexed: 05/17/2025]
Abstract
The T300A substitution in ATG16L1 associated with Crohn's disease impairs autophagy, yet up to 50% of humans are heterozygous for this allele. Here, we demonstrate that heterozygosity for the analogous substitution in mice (Atg16L1T316A), but not homozygosity, protects against lethal Salmonella enterica Typhimurium infection. One copy of Atg16L1T316A was sufficient to enhance cytokine production through inflammasome activation, which was necessary for protection. In contrast, two copies of Atg16L1T316A inhibited the autophagy-related process of LC3-associated phagocytosis (LAP) and increased susceptibility. Macrophages from human donors heterozygous for ATG16L1T300A displayed elevated inflammasome activation while homozygosity impaired LAP, similar to mice. These results clarify how the T300A substitution impacts ATG16L1 function and suggest it can be beneficial to heterozygous carriers, providing an explanation for its prevalence within the human population.
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Affiliation(s)
- Xiaomin Yao
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Eugene Rudensky
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Patricia K Martin
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Brittany M Miller
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Isabel Vargas
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Erin E Zwack
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Keenan A Lacey
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Zhengxiang He
- Precision Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Glaucia C Furtado
- Precision Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Sérgio A Lira
- Precision Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Victor J Torres
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY 10016, USA; Antimicrobial-Resistant Pathogens Program, New York University Langone Health, New York, NY 10016, USA; Department of Host-Microbe Interactions, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Bo Shopsin
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY 10016, USA; Antimicrobial-Resistant Pathogens Program, New York University Langone Health, New York, NY 10016, USA; Department of Medicine, Division of Infectious Diseases, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Ken Cadwell
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104, USA.
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2
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Zuo H, Yang Y, Su M, Huang W, Wang J, Lei G, Kong X, Chen P, Leng Y, Yuan Q, Zhao Y, Miao Y, Li M, Xu X, Lu S, Yang H, Tian L. Comparative genomic and antimicrobial resistance profiles of Salmonella strains isolated from pork and human sources in Sichuan, China. Front Microbiol 2025; 16:1515576. [PMID: 40099182 PMCID: PMC11911478 DOI: 10.3389/fmicb.2025.1515576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2024] [Accepted: 02/17/2025] [Indexed: 03/19/2025] Open
Abstract
Introduction Salmonella detection in retail pork is increasing, yet studies on its antimicrobial resistance (AMR) profiles and genomic characteristics remain limited. Moreover, it is still unclear whether certain Salmonella sequence types (STs) are consistently or rarely associated with pork as a transmission source. Sichuan province, the largest pork-production region in China, provides a critical setting to investigate these dynamics. Methods In this study, 213 Salmonella strains isolated from pork and human sources (2019-2021) underwent phenotypic AMR testing and whole-genome sequencing (WGS). Results Resistance profiling revealed a higher prevalence of AMR in the pork-derived strains, particularly in veterinary-associated antibiotics. We identified STs not observed in pork in this study, such as ST23 (S. Oranienburg) and the poultry-commonly associated ST32 (S. Infantis), suggesting potential non-pork transmission routes for these Salmonella STs. To quantify sequence type diversity within each sample source, we introduced the sequencing type index (ST index = number of different STs/ total isolates). The ST index was 32% (49/153) for human-derived isolates and 20% (12/60) for pork-derived isolates. PERMANOVA analysis revealed significant differences in the structural composition of sequence types between human- and pork-derived isolates (p = 0.001), indicating that pork may harbor specific Salmonella STs more frequently. Discussion These findings highlight the role of pork as a reservoir for certain Salmonella STs, while also implying potential non-pork transmission pathways. The ST index represents a novel metric for assessing Salmonella diversity across different sample sources, offering a better understanding of genetic variation and transmission dynamics.
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Affiliation(s)
- Haojiang Zuo
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China
- West China-PUMC C.C. Chen Institute of Health, Sichuan University, Chengdu, China
- Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province, Chengdu, China
| | - Yang Yang
- Chengdu Centre for Disease Control and Prevention, Chengdu, China
| | - Minchuan Su
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China
- West China-PUMC C.C. Chen Institute of Health, Sichuan University, Chengdu, China
| | - Weifeng Huang
- Sichuan Provincial Centre for Disease Control and Prevention, Chengdu, China
| | - Jian Wang
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China
| | - Gaopeng Lei
- Sichuan Provincial Centre for Disease Control and Prevention, Chengdu, China
| | - Ximei Kong
- Chengdu Centre for Disease Control and Prevention, Chengdu, China
| | - Peng Chen
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China
| | - Yun Leng
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China
- Chenghua Centre for Disease Control and Prevention, Chengdu, China
| | - Qiwu Yuan
- Chengdu Centre for Disease Control and Prevention, Chengdu, China
| | - Yuanyuan Zhao
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China
| | - Yanfang Miao
- Chengdu Centre for Disease Control and Prevention, Chengdu, China
| | - Ming Li
- Chengdu Centre for Disease Control and Prevention, Chengdu, China
| | - Xin Xu
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China
| | - Shihui Lu
- College of Pharmacy, Youjiang Medical University for Nationalities, Baise, China
| | - Hui Yang
- West China School of Stomatology, Sichuan University, Chengdu, China
| | - Lvbo Tian
- Sichuan Entry-Exit Inspection and Quarantine Bureau, Chengdu, China
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3
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Na-Phatthalung P, Sun S, Xie E, Wang J, Min J, Wang F. The zinc transporter Slc30a1 (ZnT1) in macrophages plays a protective role against attenuated Salmonella. eLife 2024; 13:e89509. [PMID: 39475776 PMCID: PMC11524588 DOI: 10.7554/elife.89509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 09/05/2024] [Indexed: 11/02/2024] Open
Abstract
The zinc transporter Slc30a1 plays an essential role in maintaining cellular zinc homeostasis. Despite this, its functional role in macrophages remains largely unknown. Here, we examine the function of Slc30a1 in host defense using mice models infected with an attenuated stain of Salmonella enterica Typhimurium and primary macrophages infected with the attenuated Salmonella. Bulk transcriptome sequencing in primary macrophages identifies Slc30a1 as a candidate in response to Salmonella infection. Whole-mount immunofluorescence and confocal microscopy imaging of primary macrophage and spleen from Salmonella-infected Slc30a1flag-EGFP mice demonstrate Slc30a1 expression is increased in infected macrophages with localization at the plasma membrane and in the cytosol. Lyz2-Cre-driven Slc30a1 conditional knockout mice (Slc30a1fl/fl;Lyz2-Cre) exhibit increased susceptibility to Salmonella infection compared to control littermates. We demonstrate that Slc30a1-deficient macrophages are defective in intracellular killing, which correlated with reduced activation of nuclear factor kappa B and reduction in nitric oxide (NO) production. Notably, the model exhibits intracellular zinc accumulation, demonstrating that Slc30a1 is required for zinc export. We thus conclude that zinc export enables the efficient NO-mediated antibacterial activity of macrophages to control invading Salmonella.
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Affiliation(s)
- Pinanong Na-Phatthalung
- The Second Affiliated Hospital, School of Public Health, State Key Laboratory of Experimental Hematology, Zhejiang University School of MedicineHangzhouChina
- The First Affiliated Hospital, Institute of Translational Medicine, Zhejiang University School of MedicineHangzhouChina
| | - Shumin Sun
- The Second Affiliated Hospital, School of Public Health, State Key Laboratory of Experimental Hematology, Zhejiang University School of MedicineHangzhouChina
| | - Enjun Xie
- The Second Affiliated Hospital, School of Public Health, State Key Laboratory of Experimental Hematology, Zhejiang University School of MedicineHangzhouChina
| | - Jia Wang
- School of Public Health, Zhengzhou UniversityZhengzhouChina
| | - Junxia Min
- The Second Affiliated Hospital, School of Public Health, State Key Laboratory of Experimental Hematology, Zhejiang University School of MedicineHangzhouChina
| | - Fudi Wang
- The Second Affiliated Hospital, School of Public Health, State Key Laboratory of Experimental Hematology, Zhejiang University School of MedicineHangzhouChina
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4
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Deng Q, Yang S, Huang K, Zhu Y, Sun L, Cao Y, Dong K, Li Y, Wu S, Huang R. NLRP6 induces RIP1 kinase-dependent necroptosis via TAK1-mediated p38 MAPK/MK2 phosphorylation in S. typhimurium infection. iScience 2024; 27:109339. [PMID: 38500819 PMCID: PMC10945251 DOI: 10.1016/j.isci.2024.109339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 11/16/2023] [Accepted: 02/22/2024] [Indexed: 03/20/2024] Open
Abstract
Programmed cell death (PCD) is tightly orchestrated by molecularly defined executors and signaling pathways. NLRP6, a member of cytoplasmic pattern recognition receptors, has a multifaceted role in host resistance to bacterial infection. However, whether and how NLRP6 may contribute to regulate host PCD during Gram-negative bacterial infection remain to be illuminated. Here, we report that NLRP6 promotes RIP1 kinase-mediated necroptosis, a form of lytic PCD, in both an in vitro and in vivo model of Salmonella typhimurium infection. By downregulating TAK1-mediated p38MAPK/MK2 phosphorylation, NLRP6 decreased RIP1 phosphorylation at residue S321 and subsequently increased RIP1 kinase-dependent MLKL phosphorylation. Suppression of p38MAPK/MK2 cascade not only reduced the number of dead cells caused by NLRP6 but also decreased the systemic dissemination of S. typhimurium resulting from NLRP6. Taken together, our findings provide new insights into the role and regulatory mechanism of NLRP6-associated antimicrobial responses by revealing a function for NLRP6 in regulating necroptosis.
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Affiliation(s)
- Qifeng Deng
- Department of Medical Microbiology, MOE Key Laboratory of Geriatric Diseases and Immunology, Suzhou Key Laboratory of Pathogen Bioscience and Anti-infective Medicine, School of Biology & Basic Medical Sciences, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, Guangdong 510275, P.R. China
| | - Sidi Yang
- Guangzhou National Laboratory, Guangzhou International Bio Island, Guangzhou, Guangdong 510005, P.R. China
| | - Kai Huang
- Orthopaedic Institute, Wuxi 9th People’s Hospital Affiliated to Soochow University, Wuxi, Jiangsu 214062, P.R. China
| | - Yuan Zhu
- Department of Medical Microbiology, MOE Key Laboratory of Geriatric Diseases and Immunology, Suzhou Key Laboratory of Pathogen Bioscience and Anti-infective Medicine, School of Biology & Basic Medical Sciences, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China
- Department of Laboratory Medicine, The First Affiliated Hospital of Ningbo University, Ningbo, Zhejiang 315010, P.R. China
| | - Lanqing Sun
- Department of Medical Microbiology, MOE Key Laboratory of Geriatric Diseases and Immunology, Suzhou Key Laboratory of Pathogen Bioscience and Anti-infective Medicine, School of Biology & Basic Medical Sciences, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China
- Department of Laboratory Medicine, Affiliated Hospital of Jiangnan University, Wuxi, Jiangsu 214000, P.R. China
| | - Yu Cao
- Department of Medical Microbiology, MOE Key Laboratory of Geriatric Diseases and Immunology, Suzhou Key Laboratory of Pathogen Bioscience and Anti-infective Medicine, School of Biology & Basic Medical Sciences, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Kedi Dong
- Department of Medical Microbiology, MOE Key Laboratory of Geriatric Diseases and Immunology, Suzhou Key Laboratory of Pathogen Bioscience and Anti-infective Medicine, School of Biology & Basic Medical Sciences, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China
- Department of Blood Transfusion, The First Affiliated Hospital of Ningbo University, Ningbo, Zhejiang 315010, P.R. China
| | - Yuanyuan Li
- Experimental Center, Suzhou Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, Jiangsu 215123, P.R. China
| | - Shuyan Wu
- Department of Medical Microbiology, MOE Key Laboratory of Geriatric Diseases and Immunology, Suzhou Key Laboratory of Pathogen Bioscience and Anti-infective Medicine, School of Biology & Basic Medical Sciences, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Rui Huang
- Department of Medical Microbiology, MOE Key Laboratory of Geriatric Diseases and Immunology, Suzhou Key Laboratory of Pathogen Bioscience and Anti-infective Medicine, School of Biology & Basic Medical Sciences, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China
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5
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Castanheira S, García-Del Portillo F. Evidence of two differentially regulated elongasomes in Salmonella. Commun Biol 2023; 6:923. [PMID: 37689828 PMCID: PMC10492807 DOI: 10.1038/s42003-023-05308-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 09/01/2023] [Indexed: 09/11/2023] Open
Abstract
Cell shape is genetically inherited by all forms of life. Some unicellular microbes increase niche adaptation altering shape whereas most show invariant morphology. A universal system of peptidoglycan synthases guided by cytoskeletal scaffolds defines bacterial shape. In rod-shaped bacteria, this system consists of two supramolecular complexes, the elongasome and divisome, which insert cell wall material along major and minor axes. Microbes with invariant shape are thought to use a single morphogenetic system irrespective of the occupied niche. Here, we provide evidence for two elongasomes that generate (rod) shape in the same bacterium. This phenomenon was unveiled in Salmonella, a pathogen that switches between extra- and intracellular lifestyles. The two elongasomes can be purified independently, respond to different environmental cues, and are directed by distinct peptidoglycan synthases: the canonical PBP2 and the pathogen-specific homologue PBP2SAL. The PBP2-elongasome responds to neutral pH whereas that directed by PBP2SAL assembles in acidic conditions. Moreover, the PBP2SAL-elongasome moves at a lower speed. Besides Salmonella, other human, animal, and plant pathogens encode alternative PBPs with predicted morphogenetic functions. Therefore, contrasting the view of morphological plasticity facilitating niche adaptation, some pathogens may have acquired alternative systems to preserve their shape in the host.
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Affiliation(s)
- Sónia Castanheira
- Laboratory of Intracellular Bacterial Pathogens, National Centre for Biotechnology (CNB)-CSIC, Darwin 3, 28049, Madrid, Spain
| | - Francisco García-Del Portillo
- Laboratory of Intracellular Bacterial Pathogens, National Centre for Biotechnology (CNB)-CSIC, Darwin 3, 28049, Madrid, Spain.
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6
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Jiang L, Li W, Hou X, Ma S, Wang X, Yan X, Yang B, Huang D, Liu B, Feng L. Nitric oxide is a host cue for Salmonella Typhimurium systemic infection in mice. Commun Biol 2023; 6:501. [PMID: 37161082 PMCID: PMC10169850 DOI: 10.1038/s42003-023-04876-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 04/26/2023] [Indexed: 05/11/2023] Open
Abstract
Nitric oxide (NO) is produced as an innate immune response against microbial infections. Salmonella Typhimurium (S. Typhimurium), the major causative pathogen of human gastroenteritis, induces more severe systemic disease in mice. However, host factors contributing to the difference in species-related virulence are unknown. Here, we report that host NO production promotes S. Typhimurium replication in mouse macrophages at the early infection stage by activating Salmonella pathogenicity island-2 (SPI-2). The NO signaling-induced SPI-2 activation is mediated by Fnr and PhoP/Q two-component system. NO significantly induced fnr transcription, while Fnr directly activated phoP/Q transcription. Mouse infection assays revealed a NO-dependent increase in bacterial burden in systemic organs during the initial days of infection, indicating an early contribution of host NO to virulence. This study reveals a host signaling-mediated virulence activation pathway in S. Typhimurium that contributes significantly to its systemic infection in mice, providing further insights into Salmonella pathogenesis and host-pathogen interaction.
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Affiliation(s)
- Lingyan Jiang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Wanwu Li
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Xi Hou
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Shuai Ma
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Xinyue Wang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Xiaolin Yan
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Bin Yang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Di Huang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Bin Liu
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China
| | - Lu Feng
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China.
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin, China.
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7
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Sonika S, Singh S, Mishra S, Verma S. Toxin-antitoxin systems in bacterial pathogenesis. Heliyon 2023; 9:e14220. [PMID: 37101643 PMCID: PMC10123168 DOI: 10.1016/j.heliyon.2023.e14220] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 02/27/2023] [Indexed: 03/06/2023] Open
Abstract
Toxin-Antitoxin (TA) systems are abundant in prokaryotes and play an important role in various biological processes such as plasmid maintenance, phage inhibition, stress response, biofilm formation, and dormant persister cell generation. TA loci are abundant in pathogenic intracellular micro-organisms and help in their adaptation to the harsh host environment such as nutrient deprivation, oxidation, immune response, and antimicrobials. Several studies have reported the involvement of TA loci in establishing successful infection, intracellular survival, better colonization, adaptation to host stresses, and chronic infection. Overall, the TA loci play a crucial role in bacterial virulence and pathogenesis. Nonetheless, there are some controversies about the role of TA system in stress response, biofilm and persister formation. In this review, we describe the role of the TA systems in bacterial virulence. We discuss the important features of each type of TA system and the recent discoveries identifying key contributions of TA loci in bacterial pathogenesis.
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Affiliation(s)
- Sonika Sonika
- Centre of Experimental Medicine and Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi, 221005, Uttar Pradesh, India
| | - Samer Singh
- Centre of Experimental Medicine and Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi, 221005, Uttar Pradesh, India
| | - Saurabh Mishra
- Department of Biochemistry, Institute of Sciences, Banaras Hindu University, Varanasi, 221005, Uttar Pradesh, India
| | - Shashikala Verma
- Centre of Experimental Medicine and Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi, 221005, Uttar Pradesh, India
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8
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Wellawa DH, Lam PKS, White AP, Gomis S, Allan B, Köster W. High Affinity Iron Acquisition Systems Facilitate but Are Not Essential for Colonization of Chickens by Salmonella Enteritidis. Front Microbiol 2022; 13:824052. [PMID: 35308377 PMCID: PMC8928163 DOI: 10.3389/fmicb.2022.824052] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 01/24/2022] [Indexed: 01/02/2023] Open
Abstract
The roles of TonB mediated Fe3+ (ferric iron) uptake via enterobactin (involving biosynthesis genes entABCDEF) and Fe2+ (ferrous iron) uptake through the FeoABC transporter are poorly defined in the context of chicken-Salmonella interactions. Both uptake systems are believed to be the major contributors of iron supply in the Salmonella life cycle. Current evidence suggests that these iron uptake systems play a major role in pathogenesis in mammals and as such, they represent promising antibacterial targets with therapeutic potential. We investigated the role of these iron uptake mechanisms regarding the ability of Salmonella Enteritidis (SEn) strains to colonize in a chicken infection model. Further we constructed a bioluminescent reporter to sense iron limitation during gastrointestinal colonization of Salmonella in chicken via ex vivo imaging. Our data indicated that there is some redundancy between the ferric and ferrous iron uptake mechanisms regarding iron acquisition during SEn pathogenesis in chicken. We believe that this redundancy of iron acquisition in the host reservoir may be the consequence of adaptation to unique avian environments, and thus warrants further investigation. To our knowledge, this the first report providing direct evidence that both enterobactin synthesis and FeoABC mediated iron uptake contribute to the virulence of SEn in chickens.
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Affiliation(s)
- Dinesh H Wellawa
- Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, SK, Canada.,Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Po-King S Lam
- Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, SK, Canada
| | - Aaron P White
- Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, SK, Canada.,Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Susantha Gomis
- Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Brenda Allan
- Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, SK, Canada.,Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Wolfgang Köster
- Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, SK, Canada.,Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
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9
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A detrimental role of NLRP6 in host iron metabolism during Salmonella infection. Redox Biol 2021; 49:102217. [PMID: 34942528 PMCID: PMC8695358 DOI: 10.1016/j.redox.2021.102217] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 12/17/2021] [Accepted: 12/17/2021] [Indexed: 11/27/2022] Open
Abstract
Maintaining host iron homeostasis is an essential component of nutritional immunity responsible for sequestrating iron from pathogens and controlling infection. Nucleotide-oligomerization domain-like receptors (NLRs) contribute to cytoplasmic sensing and antimicrobial response orchestration. However, it remains unknown whether and how NLRs may regulate host iron metabolism, an important component of nutritional immunity. Here, we demonstrated that NLRP6, a member of the NLR family, has an unconventional role in regulating host iron metabolism that perturbs host resistance to bacterial infection. NLRP6 deficiency is advantageous for maintaining cellular iron homeostasis in both macrophages and enterocytes through increasing the unique iron exporter ferroportin-mediated iron efflux in a nuclear factor erythroid-derived 2–related factor 2 (NRF2)-dependent manner. Additional studies uncovered a novel mechanism underlying NRF2 regulation and operating through NLRP6/AKT interaction and that causes a decrease in AKT phosphorylation, which in turn reduces NRF2 nuclear translocation. In the absence of NLRP6, increased AKT activation promotes NRF2/KEAP1 dissociation via increasing mTOR-mediated p62 phosphorylation and downregulates KEAP1 transcription by promoting FOXO3A phosphorylation. Together, our observations provide new insights into the mechanism of nutritional immunity by revealing a novel function of NLRP6 in regulating iron metabolism, and suggest NLRP6 as a therapeutic target for limiting bacterial iron acquisition.
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10
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Roche SM, Holbert S, Le Vern Y, Rossignol C, Rossignol A, Velge P, Virlogeux-Payant I. A large panel of chicken cells are invaded in vivo by Salmonella Typhimurium even when depleted of all known invasion factors. Open Biol 2021; 11:210117. [PMID: 34784793 PMCID: PMC8596019 DOI: 10.1098/rsob.210117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Poultry are the main source of human infection by Salmonella. As infected poultry are asymptomatic, identifying infected poultry farms is difficult, thus controlling animal infections is of primary importance. As cell tropism is known to govern disease, our aim was therefore to identify infected host-cell types in the organs of chicks known to be involved in Salmonella infection and investigate the role of the three known invasion factors in this process (T3SS-1, Rck and PagN). Chicks were inoculated with wild-type or isogenic fluorescent Salmonella Typhimurium mutants via the intracoelomic route. Our results show that liver, spleen, gall bladder and aortic vessels could be foci of infection, and that phagocytic and non-phagocytic cells, including immune, epithelial and endothelial cells, are invaded in vivo in each organ. Moreover, a mutant defective for the T3SS-1, Rck and PagN remained able to colonize organs like the wild-type strain and invaded non-phagocytic cells in each organ studied. As the infection of the gall bladder had not previously been described in chicks, invasion of gall bladder cells was confirmed by immunohistochemistry and infection was shown to last several weeks after inoculation. Altogether, for the first time these findings provide insights into cell tropism of Salmonella in relevant organs involved in Salmonella infection in chicks and also demonstrate that the known invasion factors are not required for entry into these cell types.
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Affiliation(s)
- S. M. Roche
- INRAE, Université de Tours, ISP, 37380 Nouzilly, France
| | - S. Holbert
- INRAE, Université de Tours, ISP, 37380 Nouzilly, France
| | - Y. Le Vern
- INRAE, Université de Tours, ISP, 37380 Nouzilly, France
| | - C. Rossignol
- INRAE, Université de Tours, ISP, 37380 Nouzilly, France
| | - A. Rossignol
- INRAE, Université de Tours, ISP, 37380 Nouzilly, France
| | - P. Velge
- INRAE, Université de Tours, ISP, 37380 Nouzilly, France
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11
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Foster N, Tang Y, Berchieri A, Geng S, Jiao X, Barrow P. Revisiting Persistent Salmonella Infection and the Carrier State: What Do We Know? Pathogens 2021; 10:1299. [PMID: 34684248 PMCID: PMC8537056 DOI: 10.3390/pathogens10101299] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 09/28/2021] [Accepted: 09/29/2021] [Indexed: 11/17/2022] Open
Abstract
One characteristic of the few Salmonella enterica serovars that produce typhoid-like infections is that disease-free persistent infection can occur for months or years in a small number of individuals post-convalescence. The bacteria continue to be shed intermittently which is a key component of the epidemiology of these infections. Persistent chronic infection occurs despite high levels of circulating specific IgG. We have reviewed the information on the basis for persistence in S. Typhi, S. Dublin, S. Gallinarum, S. Pullorum, S. Abortusovis and also S. Typhimurium in mice as a model of persistence. Persistence appears to occur in macrophages in the spleen and liver with shedding either from the gall bladder and gut or the reproductive tract. The involvement of host genetic background in defining persistence is clear from studies with the mouse but less so with human and poultry infections. There is increasing evidence that the organisms (i) modulate the host response away from the typical Th1-type response normally associated with immune clearance of an acute infection to Th2-type or an anti-inflammatory response, and that (ii) the bacteria modulate transformation of macrophage from M1 to M2 type. The bacterial factors involved in this are not yet fully understood. There are early indications that it might be possible to remodulate the response back towards a Th1 response by using cytokine therapy.
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Affiliation(s)
- Neil Foster
- SRUC Aberdeen Campus, Craibstone Estate, Ferguson Building, Aberdeen AB21 9YA, UK
| | - Ying Tang
- Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen 518055, China;
| | - Angelo Berchieri
- Departamento de Patologia Veterinária, Faculdade de Ciências Agrárias e Veterinárias, Univ Estadual Paulista, Via de Acesso Paulo Donato Castellane, s/n, 14884-900 Jaboticabal, SP, Brazil;
| | - Shizhong Geng
- Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China; (S.G.); (X.J.)
| | - Xinan Jiao
- Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China; (S.G.); (X.J.)
| | - Paul Barrow
- School of Veterinary Medicine, University of Surrey, Daphne Jackson Road, Guildford GU2 7AL, UK;
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12
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Abstract
Polysaccharides are often the most abundant antigens found on the extracellular surfaces of bacterial cells. These polysaccharides play key roles in interactions with the outside world, and for many bacterial pathogens, they represent what is presented to the human immune system. As a result, many vaccines have been or currently are being developed against carbohydrate antigens. In this review, we explore the diversity of capsular polysaccharides (CPS) in Salmonella and other selected bacterial species and explain the classification and function of CPS as vaccine antigens. Despite many vaccines being developed using carbohydrate antigens, the low immunogenicity and the diversity of infecting strains and serovars present an antigen formulation challenge to manufacturers. Vaccines tend to focus on common serovars or have changing formulations over time, reflecting the trends in human infection, which can be costly and time-consuming. We summarize the approaches to generate carbohydrate-based vaccines for Salmonella, describe vaccines that are in development and emphasize the need for an effective vaccine against non-typhoidal Salmonella strains.
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13
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Kanvatirth P, Rossi O, Restif O, Blacklaws BA, Tonks P, Grant AJ, Mastroeni P. Dual role of splenic mononuclear and polymorphonuclear cells in the outcome of ciprofloxacin treatment of Salmonella enterica infections. J Antimicrob Chemother 2021; 75:2914-2918. [PMID: 32613238 DOI: 10.1093/jac/dkaa249] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 04/29/2020] [Accepted: 05/11/2020] [Indexed: 01/27/2023] Open
Abstract
OBJECTIVES To determine the immune cell populations associated with Salmonella enterica serovar Typhimurium before and after ciprofloxacin treatment using a murine model of systemic infection. The effect of depletion of immune cells associating with Salmonella on treatment outcome was also determined. METHODS We infected mice with a Salmonella enterica serovar Typhimurium strain expressing GFP and used multicolour flow cytometry to identify splenic immune cell populations associating with GFP-positive Salmonella before and after treatment with ciprofloxacin. This was followed by depletion of different immune cell populations using antibodies and liposomes. RESULTS Our results identified CD11b+CD11chi/lo (dendritic cells/macrophages) and Ly6G+CD11b+ (neutrophils) leucocytes as the main host cell populations that are associated with Salmonella after ciprofloxacin treatment. We therefore proceeded to test the effects of depletion of such populations during treatment. We show that depletion of Ly6G+CD11b+ populations resulted in an increase in the number of viable bacterial cells in the spleen at the end of ciprofloxacin treatment. Conversely, treatment with clodronate liposomes during antimicrobial treatment, which depleted the CD11b+CD11chi/lo populations, resulted in lower numbers of viable bacteria in the tissues. CONCLUSIONS Our study identified host cells where Salmonella bacteria persist during ciprofloxacin treatment and revealed a dual and opposing effect of removal of Ly6G+CD11b+ and CD11b+CD11chi/lo host cells on the efficacy of antimicrobial treatment. This suggests a dichotomy in the role of these populations in clearance/persistence of Salmonella during antimicrobial treatment.
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Affiliation(s)
- P Kanvatirth
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
| | - O Rossi
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
| | - O Restif
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
| | - B A Blacklaws
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
| | - P Tonks
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
| | - A J Grant
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
| | - P Mastroeni
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
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14
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Agbayani G, Clark K, Sandhu JK, Hewitt M, Sad S, Murphy SP, Krishnan L. IFN-alpha receptor deficiency enhances host resistance to oral Salmonella enterica serovar Typhimurium infection during murine pregnancy. Am J Reprod Immunol 2021; 86:e13454. [PMID: 33991140 DOI: 10.1111/aji.13454] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/09/2021] [Accepted: 05/10/2021] [Indexed: 12/22/2022] Open
Abstract
PROBLEM Maternal tolerance during pregnancy increases the risk of infection with certain intracellular pathogens. Systemic Salmonella enterica serovar Typhimurium (S.Tm) infection during pregnancy in normally resistant 129X1/SvJ mice leads to severe placental infection, as well as fetal and maternal deaths. However, the effect of oral infection with S.Tm in pregnant mice and the roles of infection-induced inflammation and cell death pathways in contributing to susceptibility to infection are unclear. METHOD OF STUDY Non-pregnant and pregnant C57BL/6J wild-type (WT) and cell death pathway-altered mice (IFNAR1-/- , Caspase-1, 11-/- , RIP3-/- ) were infected orally with S.Tm. Host survival and fetal resorption were determined. Bacterial burden in mesenteric lymph nodes (MLNs), spleen, liver, and placentas was enumerated at various time points post-infection. Serum cytokine expression was measured through cytometric bead array. RESULTS Oral infection of WT mice with S.Tm on days 9-10 of gestation resulted in systemic dissemination of the bacteria, substantial placental colonization, and fetal loss 5 days post-infection. Histopathological examination of the placentas indicated that infection-induced widespread focal necrosis and neutrophil infiltration throughout the spongiotrophoblast (SpT) layer. In the non-pregnant state, IFNAR1-/- mice exhibited increased survival following oral S.Tm infection relative to Caspase-1, 11-/- , RIP3-/- , and WT mice. The increased resistance to S.Tm infection in IFNAR1-/- mice was seen during pregnancy as well, with decreased bacterial burden within MLNs, spleen, and placenta, which correlated with the decreased resorptions relative to WT and Caspase-1, 11-/- mice. CONCLUSION Oral S.Tm exposure leads to placental infection, inflammation, and resorption, whereas IFNAR1 deficiency enhances host resistance both in the non-pregnant and pregnant states.
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Affiliation(s)
- Gerard Agbayani
- Division of Life Sciences, Human Health Therapeutics, National Research Council Canada, Ottawa, ON, Canada
| | - Kristina Clark
- Division of Life Sciences, Human Health Therapeutics, National Research Council Canada, Ottawa, ON, Canada
| | - Jagdeep K Sandhu
- Division of Life Sciences, Human Health Therapeutics, National Research Council Canada, Ottawa, ON, Canada
| | - Melissa Hewitt
- Division of Life Sciences, Human Health Therapeutics, National Research Council Canada, Ottawa, ON, Canada
| | - Subash Sad
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Shawn P Murphy
- Department of Obstetrics and Gynecology, University of Rochester, Rochester, NY, USA.,Department of Microbiology and Immunology, University of Rochester, Rochester, NY, USA
| | - Lakshmi Krishnan
- Division of Life Sciences, Human Health Therapeutics, National Research Council Canada, Ottawa, ON, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
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15
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Erazo AB, Wang N, Standke L, Semeniuk AD, Fülle L, Cengiz SC, Thiem M, Weighardt H, Strugnell RA, Förster I. CCL17-expressing dendritic cells in the intestine are preferentially infected by Salmonella but CCL17 plays a redundant role in systemic dissemination. IMMUNITY INFLAMMATION AND DISEASE 2021; 9:891-904. [PMID: 33945673 PMCID: PMC8342217 DOI: 10.1002/iid3.445] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/10/2021] [Accepted: 04/13/2021] [Indexed: 12/14/2022]
Abstract
Introduction Salmonella spp. are a recognized and global cause of serious health issues from gastroenteritis to invasive disease. The mouse model of human typhoid fever, which uses Salmonella enterica serovar Typhimurium (STM) in susceptible mouse strains, has revealed that the bacteria gain access to extraintestinal tissues from the gastrointestinal tract to cause severe systemic disease. Previous analysis of the immune responses against Salmonella spp. revealed the crucial role played by dendritic cells (DCs) in carrying STM from the intestinal mucosa to the mesenteric lymph nodes (mLNs), a key site for antigen presentation and T cell activation. In this study, we investigated the influence of chemokine CCL17 on the dissemination of STM. Methods WT, CCL17/EGFP reporter, or CCL17‐deficient mice were infected orally with STM (SL1344) or mCherry‐expressing STM for 1–3 days. Colocalization of STM with CCL17‐expressing DCs in Peyer's patches (PP) and mLN was analyzed by fluorescence microscopy. In addition, DCs and myeloid cell populations from naïve and Salmonella‐infected mice were analyzed by flow cytometry. Bacterial load was determined in PP, mLN, spleen, and liver 1 and 3 days after infection. Results Histological analysis revealed that CCL17‐expressing cells are located in close proximity to STM in the dome area of PP. We show that, in mLN, STM were preferentially located within CCL17+ rather than CCL17− DCs, besides other mononuclear phagocytes, and identified the CD103+ CD11b− DC subset as the main STM‐carrying DC population in the intestine. STM infection triggered upregulation of CCL17 expression in specific intestinal DC subsets in a tissue‐specific manner. The dissemination of STM from the gut to the mLN, however, was only moderately influenced by the presence of CCL17. Conclusion CCL17‐expressing DCs were preferentially infected by Salmonella in the intestine in comparison to other DC. Nevertheless, the production of CCL17 was not essential for the early dissemination of Salmonella from the gut to systemic organs.
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Affiliation(s)
- Anna B Erazo
- Immunology and Environment, Life and Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany.,Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Nancy Wang
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Lena Standke
- Department for Innate Immunity and Metaflammation, Institute of Innate Immunity, University Hospital Bonn, Medical Faculty, Bonn, Germany
| | - Adrian D Semeniuk
- Immunology and Environment, Life and Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany.,Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Lorenz Fülle
- Immunology and Environment, Life and Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Sevgi C Cengiz
- Immunology and Environment, Life and Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Manja Thiem
- Immunology and Environment, Life and Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Heike Weighardt
- Immunology and Environment, Life and Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Richard A Strugnell
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Irmgard Förster
- Immunology and Environment, Life and Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
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16
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Hui WW, Emerson LE, Clapp B, Sheppe AE, Sharma J, del Castillo J, Ou M, Maegawa GHB, Hoffman C, Larkin, III J, Pascual DW, Ferraro MJ. Antigen-encapsulating host extracellular vesicles derived from Salmonella-infected cells stimulate pathogen-specific Th1-type responses in vivo. PLoS Pathog 2021; 17:e1009465. [PMID: 33956909 PMCID: PMC8101724 DOI: 10.1371/journal.ppat.1009465] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 03/10/2021] [Indexed: 01/22/2023] Open
Abstract
Salmonella Typhimurium is a causative agent of nontyphoidal salmonellosis, for which there is a lack of a clinically approved vaccine in humans. As an intracellular pathogen, Salmonella impacts many cellular pathways. However, the intercellular communication mechanism facilitated by host-derived small extracellular vesicles (EVs), such as exosomes, is an overlooked aspect of the host responses to this infection. We used a comprehensive proteome-based network analysis of exosomes derived from Salmonella-infected macrophages to identify host molecules that are trafficked via these EVs. This analysis predicted that the host-derived small EVs generated during macrophage infection stimulate macrophages and promote activation of T helper 1 (Th1) cells. We identified that exosomes generated during infection contain Salmonella proteins, including unique antigens previously shown to stimulate protective immune responses against Salmonella in murine studies. Furthermore, we showed that host EVs formed upon infection stimulate a mucosal immune response against Salmonella infection when delivered intranasally to BALB/c mice, a route of antigen administration known to initiate mucosal immunity. Specifically, the administration of these vesicles to animals stimulated the production of anti-Salmonella IgG antibodies, such as anti-OmpA antibodies. Exosomes also stimulated antigen-specific cell-mediated immunity. In particular, splenic mononuclear cells isolated from mice administered with exosomes derived from Salmonella-infected antigen-presenting cells increased CD4+ T cells secreting Th1-type cytokines in response to Salmonella antigens. These results demonstrate that small EVs, formed during infection, contribute to Th1 cell bias in the anti-Salmonella responses. Collectively, this study helps to unravel the role of host-derived small EVs as vehicles transmitting antigens to induce Th1-type immunity against Gram-negative bacteria. Understanding the EV-mediated defense mechanisms will allow the development of future approaches to combat bacterial infections.
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Affiliation(s)
- Winnie W. Hui
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, United States of America
- Department of Medicine, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Lisa E. Emerson
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, United States of America
| | - Beata Clapp
- Department of Infectious Diseases & Immunology, College of Veterinary Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Austin E. Sheppe
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, United States of America
| | - Jatin Sharma
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, United States of America
| | - Johanna del Castillo
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, United States of America
| | - Mark Ou
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, United States of America
| | - Gustavo H. B. Maegawa
- Department of Pediatrics, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Carol Hoffman
- Department of Infectious Diseases & Immunology, College of Veterinary Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Joseph Larkin, III
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, United States of America
| | - David W. Pascual
- Department of Infectious Diseases & Immunology, College of Veterinary Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Mariola J. Ferraro
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, United States of America
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17
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Ma S, Jiang L, Wang J, Liu X, Li W, Ma S, Feng L. Downregulation of a novel flagellar synthesis regulator AsiR promotes intracellular replication and systemic pathogenicity of Salmonella typhimurium. Virulence 2021; 12:298-311. [PMID: 33410728 PMCID: PMC7808427 DOI: 10.1080/21505594.2020.1870331] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The intracellular pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium) exploits host macrophage as a crucial survival and replicative niche. To minimize host immune response stimulated by flagellin, the expression of flagellar genes is downregulated during S. Typhimurium growth within host macrophages. However, the underlying mechanisms are largely unknown. In this study, we show that STM14_1285 (named AsiR), a putative RpiR-family transcriptional regulator, which is downregulated within macrophages as previously reported and also confirmed here, positively regulates the expression of flagellar genes by directly binding to the promoter of flhDC. By generating an asiR mutant strain and a strain that persistently expresses asiR gene within macrophages, we confirmed that the downregulation of asiR contributes positively to S. Typhimurium replication in macrophages and systemic infection in mice, which could be attributed to decreased flagellar gene expression and therefore reduced flagellin-stimulated secretion of pro-inflammatory cytokines IL-1β and TNF-α. Furthermore, the acidic pH in macrophages is identified as a signal for the downregulation of asiR and therefore flagellar genes. Collectively, our results reveal a novel acidic pH signal-mediated regulatory pathway that is utilized by S. Typhimurium to promote intracellular replication and systemic pathogenesis by repressing flagellar gene expression.
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Affiliation(s)
- Shuangshuang Ma
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University , Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University , Tianjin, China
| | - Lingyan Jiang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University , Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University , Tianjin, China
| | - Jingting Wang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University , Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University , Tianjin, China
| | - Xiaoqian Liu
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University , Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University , Tianjin, China
| | - Wanwu Li
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University , Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University , Tianjin, China
| | - Shuai Ma
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University , Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University , Tianjin, China
| | - Lu Feng
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University , Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University , Tianjin, China
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18
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Salas JR, Jaberi-Douraki M, Wen X, Volkova VV. Mathematical modeling of the 'inoculum effect': six applicable models and the MIC advancement point concept. FEMS Microbiol Lett 2020; 367:5710933. [PMID: 31960902 PMCID: PMC7317156 DOI: 10.1093/femsle/fnaa012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 01/17/2020] [Indexed: 01/09/2023] Open
Abstract
Antimicrobial treatment regimens against bacterial pathogens are designed using the drug's minimum inhibitory concentration (MIC) measured at a bacterial density of 5.7 log10(colony-forming units (CFU)/mL) in vitro. However, MIC changes with pathogen density, which varies among infectious diseases and during treatment. Incorporating this into treatment design requires realistic mathematical models of the relationships. We compared the MIC–density relationships for Gram-negative Escherichia coli and non-typhoidal Salmonella enterica subsp. enterica and Gram-positive Staphylococcus aureus and Streptococcus pneumonia (for n = 4 drug-susceptible strains per (sub)species and 1–8 log10(CFU/mL) densities), for antimicrobial classes with bactericidal activity against the (sub)species: β-lactams (ceftriaxone and oxacillin), fluoroquinolones (ciprofloxacin), aminoglycosides (gentamicin), glycopeptides (vancomycin) and oxazolidinones (linezolid). Fitting six candidate mathematical models to the log2(MIC) vs. log10(CFU/mL) curves did not identify one model best capturing the relationships across the pathogen–antimicrobial combinations. Gompertz and logistic models (rather than a previously proposed Michaelis–Menten model) fitted best most often. Importantly, the bacterial density after which the MIC sharply increases (an MIC advancement-point density) and that density's intra-(sub)species range evidently depended on the antimicrobial mechanism of action. Capturing these dependencies for the disease–pathogen–antimicrobial combination could help determine the MICs for which bacterial densities are most informative for treatment regimen design.
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Affiliation(s)
- Jessica R Salas
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS 66506, USA
| | - Majid Jaberi-Douraki
- Department of Mathematics, Kansas State University, Manhattan, KS 66506, USA.,Institute of Computational Comparative Medicine, Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, USA
| | - Xuesong Wen
- Institute of Computational Comparative Medicine, Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, USA.,Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, USA
| | - Victoriya V Volkova
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS 66506, USA.,Center for Outcomes Research and Epidemiology, Kansas State University, Manhattan, KS 66506, USA
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19
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Elnaggar MG, Jiang K, Eldesouky HE, Pei Y, Park J, Yuk SA, Meng F, Dieterly AM, Mohammad HT, Hegazy YA, Tawfeek HM, Abdel-Rahman AA, Aboutaleb AE, Seleem MN, Yeo Y. Antibacterial nanotruffles for treatment of intracellular bacterial infection. Biomaterials 2020; 262:120344. [PMID: 32905902 DOI: 10.1016/j.biomaterials.2020.120344] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 08/13/2020] [Accepted: 08/21/2020] [Indexed: 01/05/2023]
Abstract
Bacterial pathogens residing in host macrophages in intracellular infections are hard to eradicate because traditional antibiotics do not readily enter the cells or get eliminated via efflux pumps. To overcome this challenge, we developed a new particle formulation with a size amenable to selective macrophage uptake, loaded with two antibacterial agents - pexiganan and silver (Ag) nanoparticles. Here, pexiganan was loaded in 600 nm poly(lactic-co-glycolic acid) (PLGA) particles (NP), and the particle surface was modified with an iron-tannic acid supramolecular complex (pTA) that help attach Ag nanoparticles. PLGA particles coated with Ag (NP-pTA-Ag) were taken up by macrophages, but not by non-phagocytic cells, such as fibroblasts, reducing non-specific toxicity associated with Ag nanoparticles. NP-pTA-Ag loaded with pexiganan (Pex@NP-pTA-Ag) showed more potent antibacterial activity against various intracellular pathogens than NP-pTA-Ag or Pex@NP (pexiganan-loaded NP with no Ag), suggesting a collaborative function between pexiganan and Ag nanoparticles. Mouse whole-body imaging demonstrated that, upon intravenous injection, NP-pTA-Ag quickly accumulated in the liver and spleen, where intracellular bacteria tend to reside. These results support that Pex@NP-pTA-Ag is a promising strategy for the treatment of intracellular bacterial infection.
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Affiliation(s)
- Marwa G Elnaggar
- Department of Industrial and Physical Pharmacy, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN, 47907, USA; Department of Industrial Pharmacy, Faculty of Pharmacy, Assiut University, Assiut, 71526, Egypt
| | - Kunyu Jiang
- Department of Industrial and Physical Pharmacy, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN, 47907, USA; Department of Pharmaceutics, School of Pharmacy, China Medical University, 77 Puhe Road Shenyang, Liaoning, 110122, China
| | - Hassan E Eldesouky
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, 47907, USA
| | - Yihua Pei
- Department of Industrial and Physical Pharmacy, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN, 47907, USA
| | - Jinho Park
- Department of Industrial and Physical Pharmacy, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN, 47907, USA
| | - Simseok A Yuk
- Department of Industrial and Physical Pharmacy, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN, 47907, USA
| | - Fanfei Meng
- Department of Industrial and Physical Pharmacy, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN, 47907, USA
| | - Alexandra M Dieterly
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, 47907, USA
| | - Haroon T Mohammad
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, 47907, USA
| | - Youssef A Hegazy
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, 47907, USA
| | - Hesham M Tawfeek
- Department of Industrial Pharmacy, Faculty of Pharmacy, Assiut University, Assiut, 71526, Egypt
| | - Aly A Abdel-Rahman
- Department of Industrial Pharmacy, Faculty of Pharmacy, Assiut University, Assiut, 71526, Egypt
| | - Ahmed E Aboutaleb
- Department of Industrial Pharmacy, Faculty of Pharmacy, Assiut University, Assiut, 71526, Egypt
| | - Mohamed N Seleem
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, 47907, USA; Purdue Institute of Inflammation, Immunology and Infectious Disease, West Lafayette, IN, 47907, USA
| | - Yoon Yeo
- Department of Industrial and Physical Pharmacy, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN, 47907, USA; Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA.
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20
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Guo Y, Gu D, Huang T, Cao L, Zhu X, Zhou Y, Wang K, Kang X, Meng C, Jiao X, Pan Z. Essential role of Salmonella Enteritidis DNA adenine methylase in modulating inflammasome activation. BMC Microbiol 2020; 20:226. [PMID: 32723297 PMCID: PMC7389876 DOI: 10.1186/s12866-020-01919-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 07/21/2020] [Indexed: 01/08/2023] Open
Abstract
Background Salmonella Enteritidis (SE) is one of the major foodborne zoonotic pathogens of worldwide importance which can induce activation of NLRC4 and NLRP3 inflammasomes during infection. Given that the inflammasomes play an essential role in resisting bacterial infection, Salmonella has evolved various strategies to regulate activation of the inflammasome, most of which largely remain unclear. Results A transposon mutant library in SE strain C50336 was screened for the identification of the potential factors that regulate inflammasome activation. We found that T3SS-associated genes invC, prgH, and spaN were required for inflammasome activation in vitro. Interestingly, C50336 strains with deletion or overexpression of Dam were both defective in activation of caspase-1, secretion of IL-1β and phosphorylation of c-Jun N-terminal kinase (Jnk). Transcriptome sequencing (RNA-seq) results showed that most of the differentially expressed genes and enriched KEGG pathways between the C50336-VS-C50336Δdam and C50336-VS-C50336::dam groups overlapped, which includes multiple signaling pathways related to the inflammasome. C50336Δdam and C50336::dam were both found to be defective in suppressing the expression of several anti-inflammasome factors. Moreover, overexpression of Dam in macrophages by lentiviral infection could specifically enhance the activation of NLRP3 inflammasome independently via promoting the Jnk pathway. Conclusions These data indicated that Dam was essential for modulating inflammasome activation during SE infection, there were complex and dynamic interplays between Dam and the inflammasome under different conditions. New insights were provided about the battle between SE and host innate immunological mechanisms.
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Affiliation(s)
- Yaxin Guo
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China.,Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of A griculture of China, Yangzhou University, Yangzhou, Jiangsu, China.,Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, China
| | - Dan Gu
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China.,Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of A griculture of China, Yangzhou University, Yangzhou, Jiangsu, China.,Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, China
| | - Tingting Huang
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China.,Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of A griculture of China, Yangzhou University, Yangzhou, Jiangsu, China.,Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, China
| | - Liyan Cao
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China.,Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of A griculture of China, Yangzhou University, Yangzhou, Jiangsu, China.,Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, China
| | - Xinyu Zhu
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China.,Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of A griculture of China, Yangzhou University, Yangzhou, Jiangsu, China.,Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, China
| | - Yi Zhou
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China.,Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of A griculture of China, Yangzhou University, Yangzhou, Jiangsu, China.,Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, China
| | - Kangru Wang
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China.,Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of A griculture of China, Yangzhou University, Yangzhou, Jiangsu, China.,Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, China
| | - Xilong Kang
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China.,Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of A griculture of China, Yangzhou University, Yangzhou, Jiangsu, China.,Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, China
| | - Chuang Meng
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China.,Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of A griculture of China, Yangzhou University, Yangzhou, Jiangsu, China.,Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, China
| | - Xinan Jiao
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China. .,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China. .,Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of A griculture of China, Yangzhou University, Yangzhou, Jiangsu, China. .,Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, China.
| | - Zhiming Pan
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China. .,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China. .,Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of A griculture of China, Yangzhou University, Yangzhou, Jiangsu, China. .,Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, China.
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21
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Carruthers J, Lythe G, López-García M, Gillard J, Laws TR, Lukaszewski R, Molina-París C. Stochastic dynamics of Francisella tularensis infection and replication. PLoS Comput Biol 2020; 16:e1007752. [PMID: 32479491 PMCID: PMC7304631 DOI: 10.1371/journal.pcbi.1007752] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 06/19/2020] [Accepted: 02/27/2020] [Indexed: 12/12/2022] Open
Abstract
We study the pathogenesis of Francisella tularensis infection with an experimental mouse model, agent-based computation and mathematical analysis. Following inhalational exposure to Francisella tularensis SCHU S4, a small initial number of bacteria enter lung host cells and proliferate inside them, eventually destroying the host cell and releasing numerous copies that infect other cells. Our analysis of disease progression is based on a stochastic model of a population of infectious agents inside one host cell, extending the birth-and-death process by the occurrence of catastrophes: cell rupture events that affect all bacteria in a cell simultaneously. Closed expressions are obtained for the survival function of an infected cell, the number of bacteria released as a function of time after infection, and the total bacterial load. We compare our mathematical analysis with the results of agent-based computation and, making use of approximate Bayesian statistical inference, with experimental measurements carried out after murine aerosol infection with the virulent SCHU S4 strain of the bacterium Francisella tularensis, that infects alveolar macrophages. The posterior distribution of the rate of replication of intracellular bacteria is consistent with the estimate that the time between rounds of bacterial division is less than 6 hours in vivo. Infecting a host cell is required for the replication of many types of bacteria and viruses. In some cases, infected cells release new infectious agents continuously over their lifetime. In others, such as the Francisella tularensis bacterium studied here, they are released in a single burst that coincides with the cell’s death. We show how a stochastic model, the birth-and-death process with catastrophe, can be used to characterise infection in a single cell, thereby allowing us to account for burst events and quantify the kinetics of pathogenesis in the lung, the initial site of infection, as well as in other organs that the infection spreads to. We learn about the parameters of the mathematical model of Francisella tularensis infection making use of the experimental measurements of bacterial loads, together with approximate Bayesian statistical inference methods. The most important parameter describing the pathogenesis is the rate of replication of intracellular bacteria.
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Affiliation(s)
- Jonathan Carruthers
- Department of Applied Mathematics, University of Leeds, Leeds, United Kingdom
| | - Grant Lythe
- Department of Applied Mathematics, University of Leeds, Leeds, United Kingdom
| | - Martín López-García
- Department of Applied Mathematics, University of Leeds, Leeds, United Kingdom
| | - Joseph Gillard
- CBR Division, Defence Science and Technology Laboratory, Salisbury, United Kingdom
| | - Thomas R. Laws
- CBR Division, Defence Science and Technology Laboratory, Salisbury, United Kingdom
| | - Roman Lukaszewski
- CBR Division, Defence Science and Technology Laboratory, Salisbury, United Kingdom
| | - Carmen Molina-París
- Department of Applied Mathematics, University of Leeds, Leeds, United Kingdom
- * E-mail:
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22
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Chakraborty S, Liu L, Fitzsimmons L, Porwollik S, Kim JS, Desai P, McClelland M, Vazquez-Torres A. Glycolytic reprograming in Salmonella counters NOX2-mediated dissipation of ΔpH. Nat Commun 2020; 11:1783. [PMID: 32286292 PMCID: PMC7156505 DOI: 10.1038/s41467-020-15604-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 03/09/2020] [Indexed: 01/16/2023] Open
Abstract
The microbial adaptations to the respiratory burst remain poorly understood, and establishing how the NADPH oxidase (NOX2) kills microbes has proven elusive. Here we demonstrate that NOX2 collapses the ΔpH of intracellular Salmonella Typhimurium. The depolarization experienced by Salmonella undergoing oxidative stress impairs folding of periplasmic proteins. Depolarization in respiring Salmonella mediates intense bactericidal activity of reactive oxygen species (ROS). Salmonella adapts to the challenges oxidative stress imposes on membrane bioenergetics by shifting redox balance to glycolysis and fermentation, thereby diminishing electron flow through the membrane, meeting energetic requirements and anaplerotically generating tricarboxylic acid intermediates. By diverting electrons away from the respiratory chain, glycolysis also enables thiol/disulfide exchange-mediated folding of bacterial cell envelope proteins during periods of oxidative stress. Thus, primordial metabolic pathways, already present in bacteria before aerobic respiration evolved, offer a solution to the stress ROS exert on molecular targets at the bacterial cell envelope. Chakraborty et al. show that phagocyte NADPH oxidase (NOX2) collapses the ΔpH of intracellular Salmonella Typhimurium, leading to oxidative damage of cell envelope proteins. Salmonella responds by shifting redox balance from respiration to glycolysis and fermentation, thereby facilitating folding of periplasmic functions.
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Affiliation(s)
- Sangeeta Chakraborty
- Department of Immunology & Microbiology, University of Colorado School of Medicine, 12800 E. 19th Ave, Mail Box 8333, Aurora, CO, 80045, USA
| | - Lin Liu
- Department of Immunology & Microbiology, University of Colorado School of Medicine, 12800 E. 19th Ave, Mail Box 8333, Aurora, CO, 80045, USA
| | - Liam Fitzsimmons
- Department of Immunology & Microbiology, University of Colorado School of Medicine, 12800 E. 19th Ave, Mail Box 8333, Aurora, CO, 80045, USA
| | - Steffen Porwollik
- Department of Microbiology and Molecular Genetics, University of California Irvine School of Medicine, 240 Med Sci Bldg., Irvine, CA, 92697, USA
| | - Ju-Sim Kim
- Department of Immunology & Microbiology, University of Colorado School of Medicine, 12800 E. 19th Ave, Mail Box 8333, Aurora, CO, 80045, USA
| | - Prerak Desai
- Department of Microbiology and Molecular Genetics, University of California Irvine School of Medicine, 240 Med Sci Bldg., Irvine, CA, 92697, USA
| | - Michael McClelland
- Department of Microbiology and Molecular Genetics, University of California Irvine School of Medicine, 240 Med Sci Bldg., Irvine, CA, 92697, USA
| | - Andres Vazquez-Torres
- Department of Immunology & Microbiology, University of Colorado School of Medicine, 12800 E. 19th Ave, Mail Box 8333, Aurora, CO, 80045, USA. .,Veterans Affairs Eastern Colorado Health Care System, Denver, CO, USA.
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23
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Luo G, Sun Y, Huang L, Su Y, Zhao L, Qin Y, Xu X, Yan Q. Time-resolved dual RNA-seq of tissue uncovers Pseudomonas plecoglossicida key virulence genes in host-pathogen interaction with Epinephelus coioides. Environ Microbiol 2019; 22:677-693. [PMID: 31797531 DOI: 10.1111/1462-2920.14884] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 12/02/2019] [Indexed: 01/19/2023]
Abstract
Bacterial pathogen-host interactions are highly dynamic, regulated processes that have been primarily investigated using in vitro assays. The dynamics of bacterial pathogen-host interplay in vivo are poorly understood. Using time-resolved dual RNA-seq in a Pseudomonas plecoglossicida-Epinephelus coioides infection model, we observed that bacterial genes encoding classical virulence factors and host genes involved in immune regulation were dynamically expressed during infection. Using network inferencing, we were able to predict interspecies regulatory networks linking bacterial virulence genes to host immune genes. Together with gene co-expression network analysis of the pathogen, secY was predicted to be a key virulence gene for P. plecoglossicida pathogenicity in the host, fliN was predicted to be a less important virulence gene. The results of bioinformatics prediction were confirmed by animal infection experiments. Our work provides the first paradigm to study dynamic alterations of bacterial pathogen and host interactions based on the elucidation of time-resolved interactive transcriptomes in vivo, and may be developed into a novel and universal method for revealing the true complexity of the bacterial infection process.
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Affiliation(s)
- Gang Luo
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, PR China
| | - Yujia Sun
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, PR China
| | - Lixing Huang
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, PR China
| | - Yongquan Su
- State Key Laboratory of Large Yellow Croaker Breeding, Ningde, Fujian, 352000, PR China
| | - Lingmin Zhao
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, PR China
| | - Yingxue Qin
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, PR China
| | - Xiaojin Xu
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, PR China
| | - Qingpi Yan
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, PR China.,State Key Laboratory of Large Yellow Croaker Breeding, Ningde, Fujian, 352000, PR China
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24
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Song X, Zhang H, Liu X, Yuan J, Wang P, Lv R, Yang B, Huang D, Jiang L. The putative transcriptional regulator STM14_3563 facilitates Salmonella Typhimurium pathogenicity by activating virulence-related genes. Int Microbiol 2019; 23:381-390. [PMID: 31832871 DOI: 10.1007/s10123-019-00110-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 11/24/2019] [Accepted: 11/28/2019] [Indexed: 11/30/2022]
Abstract
Salmonella enterica serovar Typhimurium (S. Typhimurium) is an important gram-negative intracellular pathogen that infects humans and animals. More than 50 putative regulatory proteins have been identified in the S. Typhimurium genome, but few have been clearly defined. In this study, the physiological function and regulatory role of STM14_3563, which encodes a ParD family putative transcriptional regulator in S. Typhimurium, were investigated. Macrophage replication assays and mice experiments revealed that S. Typhimurium showed reduced growth in murine macrophages and attenuated virulence in mice owing to deletion of STM14_3563 gene. RNA sequencing (RNA-Seq) data showed that STM14_3563 exerts wide-ranging effects on gene expression in S. Typhimurium. STM14_3563 activates the expression of several genes encoded in Salmonella pathogenicity island (SPI)-6, SPI-12, and SPI-13, which are required for intracellular replication of S. Typhimurium. Additionally, the global transcriptional regulator Fis was found to directly activate STM14_3563 expression by binding to the STM14_3563 promoter. These results indicate that STM14_3563 is involved in the regulation of a variety of virulence-related genes in S. Typhimurium that contribute to its growth in macrophages and virulence in mice.
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Affiliation(s)
- Xiaorui Song
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, 300457, China.,The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, 300071, China.,Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin, 300457, China.,College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Huan Zhang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, 300457, China.,The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, 300071, China.,Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin, 300457, China.,College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Xiaoqian Liu
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, 300457, China.,The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, 300071, China.,Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin, 300457, China
| | - Jian Yuan
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, 300457, China.,The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, 300071, China.,Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin, 300457, China
| | - Peisheng Wang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, 300457, China.,The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, 300071, China.,Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin, 300457, China.,College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Runxia Lv
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, 300457, China.,The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, 300071, China.,Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin, 300457, China
| | - Bin Yang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, 300457, China.,The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, 300071, China.,Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin, 300457, China
| | - Di Huang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, 300457, China.,The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, 300071, China.,Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin, 300457, China
| | - Lingyan Jiang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, 300457, China. .,The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, 300071, China. .,Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin, 300457, China.
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25
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Rosenkilde CEH, Munck C, Porse A, Linkevicius M, Andersson DI, Sommer MOA. Collateral sensitivity constrains resistance evolution of the CTX-M-15 β-lactamase. Nat Commun 2019; 10:618. [PMID: 30728359 PMCID: PMC6365502 DOI: 10.1038/s41467-019-08529-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 01/15/2019] [Indexed: 11/25/2022] Open
Abstract
Antibiotic resistance is a major challenge to global public health. Discovery of new antibiotics is slow and to ensure proper treatment of bacterial infections new strategies are needed. One way to curb the development of antibiotic resistance is to design drug combinations where the development of resistance against one drug leads to collateral sensitivity to the other drug. Here we study collateral sensitivity patterns of the globally distributed extended-spectrum β-lactamase CTX-M-15, and find three non-synonymous mutations with increased resistance against mecillinam or piperacillin-tazobactam that simultaneously confer full susceptibility to several cephalosporin drugs. We show in vitro and in mice that a combination of mecillinam and cefotaxime eliminates both wild-type and resistant CTX-M-15. Our results indicate that mecillinam and cefotaxime in combination constrain resistance evolution of CTX-M-15, and illustrate how drug combinations can be rationally designed to limit the resistance evolution of horizontally transferred genes by exploiting collateral sensitivity patterns.
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Affiliation(s)
- Carola E H Rosenkilde
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, DK-2800, Lyngby, Denmark
| | - Christian Munck
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, DK-2800, Lyngby, Denmark
- Department of Systems Biology, Columbia University, New York, NY, USA
| | - Andreas Porse
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, DK-2800, Lyngby, Denmark
| | - Marius Linkevicius
- Department of Medical Biochemistry and Microbiology, Uppsala University, Box 582, SE-751 23, Uppsala, Sweden
| | - Dan I Andersson
- Department of Medical Biochemistry and Microbiology, Uppsala University, Box 582, SE-751 23, Uppsala, Sweden
| | - Morten O A Sommer
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, DK-2800, Lyngby, Denmark.
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26
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Salmonella-induced thrombi in mice develop asynchronously in the spleen and liver and are not effective bacterial traps. Blood 2018; 133:600-604. [PMID: 30401709 DOI: 10.1182/blood-2018-08-867267] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Accepted: 10/28/2018] [Indexed: 11/20/2022] Open
Abstract
Thrombosis is a frequent, life-threatening complication of systemic infection associated with multiple organ damage. We have previously described a novel mechanism of inflammation-driven thrombosis induced by Salmonella Typhimurium infection of mice. Thrombosis in the liver develops 7 days after infection, persisting after the infection resolves, and is monocytic cell dependent. Unexpectedly, thrombosis was not prominent in the spleen at this time, despite carrying a similar bacterial burden as the liver. In this study, we show that thrombosis does occur in the spleen but with strikingly accelerated kinetics compared with the liver, being evident by 24 hours and resolving rapidly thereafter. The distinct kinetics of thrombosis and bacterial burden provides a test of the hypothesis that thrombi form in healthy vessels to trap or remove bacteria from the circulation, often termed immunothrombosis. Remarkably, despite bacteria being detected throughout infected spleens and livers in the early days of infection, immunohistological analysis of tissue sections show that thrombi contain very low numbers of bacteria. In contrast, bacteria are present throughout platelet aggregates induced by Salmonella in vitro. Therefore, we show that thrombosis develops with organ-specific kinetics and challenge the universality of immunothrombosis as a mechanism to capture bacteria in vivo.
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27
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Ercoli G, Fernandes VE, Chung WY, Wanford JJ, Thomson S, Bayliss CD, Straatman K, Crocker PR, Dennison A, Martinez-Pomares L, Andrew PW, Moxon ER, Oggioni MR. Intracellular replication of Streptococcus pneumoniae inside splenic macrophages serves as a reservoir for septicaemia. Nat Microbiol 2018; 3:600-610. [PMID: 29662129 PMCID: PMC6207342 DOI: 10.1038/s41564-018-0147-1] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 03/08/2018] [Indexed: 01/21/2023]
Abstract
Bacterial septicaemia is a major cause of mortality, but its pathogenesis remains poorly understood. In experimental pneumococcal murine intravenous infection, an initial reduction of bacteria in the blood is followed hours later by a fatal septicaemia. These events represent a population bottleneck driven by efficient clearance of pneumococci by splenic macrophages and neutrophils, but as we show in this study, accompanied by occasional intracellular replication of bacteria that are taken up by a subset of CD169+ splenic macrophages. In this model, proliferation of these sequestered bacteria provides a reservoir for dissemination of pneumococci into the bloodstream, as demonstrated by its prevention using an anti-CD169 monoclonal antibody treatment. Intracellular replication of pneumococci within CD169+ splenic macrophages was also observed in an ex vivo porcine spleen, where the microanatomy is comparable with humans. We also showed that macrolides, which effectively penetrate macrophages, prevented septicaemia, whereas beta-lactams, with inefficient intracellular penetration, failed to prevent dissemination to the blood. Our findings define a shift in our understanding of the pneumococcus from an exclusively extracellular pathogen to one with an intracellular phase. These findings open the door to the development of treatments that target this early, previously unrecognized intracellular phase of bacterial sepsis.
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Affiliation(s)
- Giuseppe Ercoli
- Department of Genetics and Genome Biology, University of Leicester, Leicester, UK
| | - Vitor E Fernandes
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - Wen Y Chung
- Hepato-Pancreato-Biliary Unit, Leicester General Hospital, University of Hospitals of Leicester, NHS Trust, Leicester, UK
| | - Joseph J Wanford
- Department of Genetics and Genome Biology, University of Leicester, Leicester, UK
| | - Sarah Thomson
- Division of Cell Signalling and Immunology, School of Life Sciences, University of Dundee, Dundee, UK
| | | | - Kornelis Straatman
- Centre for Core Biotechnology Services, University of Leicester, Leicester, UK
| | - Paul R Crocker
- Division of Cell Signalling and Immunology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Ashley Dennison
- Hepato-Pancreato-Biliary Unit, Leicester General Hospital, University of Hospitals of Leicester, NHS Trust, Leicester, UK
| | - Luisa Martinez-Pomares
- School of Life Sciences, Faculty of Medicine & Health Sciences, University of Nottingham, Nottingham, UK
| | - Peter W Andrew
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | | | - Marco R Oggioni
- Department of Genetics and Genome Biology, University of Leicester, Leicester, UK.
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28
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Immunological bases of increased susceptibility to invasive nontyphoidal Salmonella infection in children with malaria and anaemia. Microbes Infect 2017; 20:589-598. [PMID: 29248635 PMCID: PMC6250906 DOI: 10.1016/j.micinf.2017.11.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 11/17/2017] [Accepted: 11/20/2017] [Indexed: 01/01/2023]
Abstract
Malaria and anaemia are key underlying factors for iNTS disease in African children. Knowledge of clinical and epidemiological risk-factors for iNTS disease has not been paralleled by an in-depth knowledge of the immunobiology of the disease. Herein, we review human and animal studies on mechanisms of increased susceptibility to iNTS in children.
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29
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miR-143 inhibits intracellular salmonella growth by targeting ATP6V1A in macrophage cells in pig. Res Vet Sci 2017; 117:138-143. [PMID: 29274513 DOI: 10.1016/j.rvsc.2017.12.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 10/16/2017] [Accepted: 12/14/2017] [Indexed: 12/27/2022]
Abstract
Salmonella infects many vertebrate species, and animals such as pigs can be colonized with Salmonella and become established carriers. Analyzing the roles of microRNA in intracellular proliferation is important for understanding the process of Salmonella infection. The objective of this study is to verify the regulation effect of miR-143 on ATP6V1A and its functions in the intracellular growth of Salmonella. A new miR-143 binding site was discovered in the 3' UTR of ATP6V1A using a newly developed prediction tool. The binding site was confirmed by binding site deletion assay. Real-time PCR results indicated that ATP6V1A was predominantly expressed in bone-marrow-derived macrophages, and the expression of miR-143 in different tissues was negatively correlated with ATP6V1A. The Salmonella proliferation assay showed that the expression of miR-143 could inhibit intracellular Salmonella growth in macrophages by target ATP6V1A. The results strongly suggest that miR-143 plays important regulatory roles in the development of Salmonella infection in animals.
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30
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Price DJ, Breuzé A, Dybowski R, Mastroeni P, Restif O. An efficient moments-based inference method for within-host bacterial infection dynamics. PLoS Comput Biol 2017; 13:e1005841. [PMID: 29155811 PMCID: PMC5714343 DOI: 10.1371/journal.pcbi.1005841] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 12/04/2017] [Accepted: 10/22/2017] [Indexed: 11/18/2022] Open
Abstract
Over the last ten years, isogenic tagging (IT) has revolutionised the study of bacterial infection dynamics in laboratory animal models. However, quantitative analysis of IT data has been hindered by the piecemeal development of relevant statistical models. The most promising approach relies on stochastic Markovian models of bacterial population dynamics within and among organs. Here we present an efficient numerical method to fit such stochastic dynamic models to in vivo experimental IT data. A common approach to statistical inference with stochastic dynamic models relies on producing large numbers of simulations, but this remains a slow and inefficient method for all but simple problems, especially when tracking bacteria in multiple locations simultaneously. Instead, we derive and solve the systems of ordinary differential equations for the two lower-order moments of the stochastic variables (mean, variance and covariance). For any given model structure, and assuming linear dynamic rates, we demonstrate how the model parameters can be efficiently and accurately estimated by divergence minimisation. We then apply our method to an experimental dataset and compare the estimates and goodness-of-fit to those obtained by maximum likelihood estimation. While both sets of parameter estimates had overlapping confidence regions, the new method produced lower values for the division and death rates of bacteria: these improved the goodness-of-fit at the second time point at the expense of that of the first time point. This flexible framework can easily be applied to a range of experimental systems. Its computational efficiency paves the way for model comparison and optimal experimental design.
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Affiliation(s)
- David J. Price
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Alexandre Breuzé
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
- ENSTA-ParisTech, Palaiseau, France
| | - Richard Dybowski
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Piero Mastroeni
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Olivier Restif
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
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31
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Fels U, Gevaert K, Van Damme P. Proteogenomics in Aid of Host-Pathogen Interaction Studies: A Bacterial Perspective. Proteomes 2017; 5:E26. [PMID: 29019919 PMCID: PMC5748561 DOI: 10.3390/proteomes5040026] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 10/02/2017] [Accepted: 10/08/2017] [Indexed: 12/17/2022] Open
Abstract
By providing useful tools to study host-pathogen interactions, next-generation omics has recently enabled the study of gene expression changes in both pathogen and infected host simultaneously. However, since great discriminative power is required to study pathogen and host simultaneously throughout the infection process, the depth of quantitative gene expression profiling has proven to be unsatisfactory when focusing on bacterial pathogens, thus preferentially requiring specific strategies or the development of novel methodologies based on complementary omics approaches. In this review, we focus on the difficulties encountered when making use of proteogenomics approaches to study bacterial pathogenesis. In addition, we review different omics strategies (i.e., transcriptomics, proteomics and secretomics) and their applications for studying interactions of pathogens with their host.
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Affiliation(s)
- Ursula Fels
- VIB-UGent Center for Medical Biotechnology, Albert Baertsoenkaai 3, B-9000 Ghent, Belgium.
- Department of Biochemistry, Ghent University, B-9000 Ghent, Belgium.
| | - Kris Gevaert
- VIB-UGent Center for Medical Biotechnology, Albert Baertsoenkaai 3, B-9000 Ghent, Belgium.
- Department of Biochemistry, Ghent University, B-9000 Ghent, Belgium.
| | - Petra Van Damme
- VIB-UGent Center for Medical Biotechnology, Albert Baertsoenkaai 3, B-9000 Ghent, Belgium.
- Department of Biochemistry, Ghent University, B-9000 Ghent, Belgium.
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32
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Palmer AD, Slauch JM. Mechanisms of Salmonella pathogenesis in animal models. HUMAN AND ECOLOGICAL RISK ASSESSMENT : HERA 2017; 23:1877-1892. [PMID: 31031557 PMCID: PMC6484827 DOI: 10.1080/10807039.2017.1353903] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Animal models play an important role in understanding the mechanisms of bacterial pathogenesis. Here we review recent studies of Salmonella infection in various animal models. Although mice are a classic animal model for Salmonella, mice do not normally get diarrhea, raising the question of how well the model represents normal human infection. However, pretreatment of mice with oral streptomycin, which apparently reduces the normal microbiota, leads to an inflammatory diarrheal response upon oral infection with Salmonella. This has led to a re-evaluation of the role of various Salmonella virulence factors in colonization of the intestine and induction of diarrhea. Indeed, it is now clear that Salmonella purposefully induces inflammation, which leads to the production of both carbon sources and terminal electron acceptors by the host that allow Salmonella to outgrow the normal intestinal microbiota. Overall use of this modified mouse model provides a more nuanced understanding of Salmonella intestinal infection in the context of the microbiota with implications for the ability to predict human risk.
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Affiliation(s)
- Alexander D Palmer
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - James M Slauch
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
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33
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Pucciarelli MG, García-Del Portillo F. Salmonella Intracellular Lifestyles and Their Impact on Host-to-Host Transmission. Microbiol Spectr 2017; 5:10.1128/microbiolspec.mtbp-0009-2016. [PMID: 28730976 PMCID: PMC11687531 DOI: 10.1128/microbiolspec.mtbp-0009-2016] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Indexed: 12/11/2022] Open
Abstract
More than a century ago, infections by Salmonella were already associated with foodborne enteric diseases with high morbidity in humans and cattle. Intestinal inflammation and diarrhea are hallmarks of infections caused by nontyphoidal Salmonella serovars, and these pathologies facilitate pathogen transmission to the environment. In those early times, physicians and microbiologists also realized that typhoid and paratyphoid fever caused by some Salmonella serovars could be transmitted by "carriers," individuals outwardly healthy or at most suffering from some minor chronic complaint. In his pioneering study of the nontyphoidal serovar Typhimurium in 1967, Takeuchi published the first images of intracellular bacteria enclosed by membrane-bound vacuoles in the initial stages of the intestinal epithelium penetration. These compartments, called Salmonella-containing vacuoles, are highly dynamic phagosomes with differing biogenesis depending on the host cell type. Single-cell studies involving real-time imaging and gene expression profiling, together with new approaches based on genetic reporters sensitive to growth rate, have uncovered unprecedented heterogeneous responses in intracellular bacteria. Subpopulations of intracellular bacteria displaying fast, reduced, or no growth, as well as cytosolic and intravacuolar bacteria, have been reported in both in vitro and in vivo infection models. Recent investigations, most of them focused on the serovar Typhimurium, point to the selection of persisting bacteria inside macrophages or following an autophagy attack in fibroblasts. Here, we discuss these heterogeneous intracellular lifestyles and speculate on how these disparate behaviors may impact host-to-host transmissibility of Salmonella serovars.
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Affiliation(s)
- M Graciela Pucciarelli
- Laboratory of Intracellular Bacterial Pathogens, Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid, Spain
- Centro de Biología Molecular Severo Ochoa (CBMSO-CSIC), Departamento de Biología Molecular, Universidad Autónoma de Madrid, Madrid, Spain
| | - Francisco García-Del Portillo
- Laboratory of Intracellular Bacterial Pathogens, Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid, Spain
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Abstract
Inflammasomes are macromolecular cytoplasmic complexes that act as signaling platforms for the activation of inflammatory caspases. Their activation triggers the processing and secretion of the pro-inflammatory cytokines IL-1β and IL-18, as well as the induction of a specialized form of inflammatory cell death termed pyroptosis. Here, we review the mechanisms of inflammasome activation triggered by the intracellular pathogen Salmonella enterica serovar Typhimurium. We highlight the different inflammasome subfamilies utilized by macrophages, neutrophils, dendritic cells, and intestinal epithelial cells response to a Salmonella infection as well as the Salmonella ligands that trigger each inflammasome's formation. We also discuss the evasion strategies utilized by Salmonella to avoid inflammasome detection. Overall, inflammasomes play a key and multilayered role at distinct stages of host cell defense against Salmonella infection.
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Bile Acid Administration Elicits an Intestinal Antimicrobial Program and Reduces the Bacterial Burden in Two Mouse Models of Enteric Infection. Infect Immun 2017; 85:IAI.00942-16. [PMID: 28348052 DOI: 10.1128/iai.00942-16] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 03/20/2017] [Indexed: 12/18/2022] Open
Abstract
In addition to their chemical antimicrobial nature, bile acids are thought to have other functions in the homeostatic control of gastrointestinal immunity. However, those functions have remained largely undefined. In this work, we used ileal explants and mouse models of bile acid administration to investigate the role of bile acids in the regulation of the intestinal antimicrobial response. Mice fed on a diet supplemented with 0.1% chenodeoxycholic acid (CDCA) showed an upregulated expression of Paneth cell α-defensins as well as an increased synthesis of the type-C lectins Reg3b and Reg3g by the ileal epithelium. CDCA acted on several epithelial cell types, by a mechanism independent from farnesoid X receptor (FXR) and not involving STAT3 or β-catenin activation. CDCA feeding did not change the relative abundance of major commensal bacterial groups of the ileum, as shown by 16S analyses. However, administration of CDCA increased the expression of ileal Muc2 and induced a change in the composition of the mucosal immune cell repertoire, decreasing the proportion of Ly6G+ and CD68+ cells, while increasing the relative amount of IgGκ+ B cells. Oral administration of CDCA to mice attenuated infections with the bile-resistant pathogens Salmonella enterica serovar Typhimurium and Citrobacter rodentium, promoting lower systemic colonization and faster bacteria clearance, respectively. Our results demonstrate that bile acid signaling in the ileum triggers an antimicrobial program that can be potentially used as a therapeutic option against intestinal bacterial infections.
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Barrila J, Yang J, Crabbé A, Sarker SF, Liu Y, Ott CM, Nelman-Gonzalez MA, Clemett SJ, Nydam SD, Forsyth RJ, Davis RR, Crucian BE, Quiriarte H, Roland KL, Brenneman K, Sams C, Loscher C, Nickerson CA. Three-dimensional organotypic co-culture model of intestinal epithelial cells and macrophages to study Salmonella enterica colonization patterns. NPJ Microgravity 2017; 3:10. [PMID: 28649632 PMCID: PMC5460263 DOI: 10.1038/s41526-017-0011-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 11/23/2016] [Accepted: 12/12/2016] [Indexed: 12/21/2022] Open
Abstract
Three-dimensional models of human intestinal epithelium mimic the differentiated form and function of parental tissues often not exhibited by two-dimensional monolayers and respond to Salmonella in key ways that reflect in vivo infections. To further enhance the physiological relevance of three-dimensional models to more closely approximate in vivo intestinal microenvironments encountered by Salmonella, we developed and validated a novel three-dimensional co-culture infection model of colonic epithelial cells and macrophages using the NASA Rotating Wall Vessel bioreactor. First, U937 cells were activated upon collagen-coated scaffolds. HT-29 epithelial cells were then added and the three-dimensional model was cultured in the bioreactor until optimal differentiation was reached, as assessed by immunohistochemical profiling and bead uptake assays. The new co-culture model exhibited in vivo-like structural and phenotypic characteristics, including three-dimensional architecture, apical-basolateral polarity, well-formed tight/adherens junctions, mucin, multiple epithelial cell types, and functional macrophages. Phagocytic activity of macrophages was confirmed by uptake of inert, bacteria-sized beads. Contribution of macrophages to infection was assessed by colonization studies of Salmonella pathovars with different host adaptations and disease phenotypes (Typhimurium ST19 strain SL1344 and ST313 strain D23580; Typhi Ty2). In addition, Salmonella were cultured aerobically or microaerobically, recapitulating environments encountered prior to and during intestinal infection, respectively. All Salmonella strains exhibited decreased colonization in co-culture (HT-29-U937) relative to epithelial (HT-29) models, indicating antimicrobial function of macrophages. Interestingly, D23580 exhibited enhanced replication/survival in both models following invasion. Pathovar-specific differences in colonization and intracellular co-localization patterns were observed. These findings emphasize the power of incorporating a series of related three-dimensional models within a study to identify microenvironmental factors important for regulating infection.
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Affiliation(s)
- Jennifer Barrila
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ USA
| | - Jiseon Yang
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ USA
| | - Aurélie Crabbé
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ USA
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Shameema F. Sarker
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ USA
| | - Yulong Liu
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ USA
| | - C. Mark Ott
- Biomedical Research and Environmental Sciences Division, NASA Johnson Space Center, Houston, TX USA
| | | | | | - Seth D. Nydam
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ USA
| | - Rebecca J. Forsyth
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ USA
| | - Richard R. Davis
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ USA
| | - Brian E. Crucian
- Biomedical Research and Environmental Sciences Division, NASA Johnson Space Center, Houston, TX USA
| | | | - Kenneth L. Roland
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ USA
| | - Karen Brenneman
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ USA
| | - Clarence Sams
- Biomedical Research and Environmental Sciences Division, NASA Johnson Space Center, Houston, TX USA
| | - Christine Loscher
- Immunomodulation Research Group, School of Biotechnology, Dublin City University, Glasnevin, Ireland
| | - Cheryl A. Nickerson
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ USA
- School of Life Sciences, Arizona State University, Tempe, AZ USA
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37
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Ahmed W, Zheng K, Liu ZF. Small Non-Coding RNAs: New Insights in Modulation of Host Immune Response by Intracellular Bacterial Pathogens. Front Immunol 2016; 7:431. [PMID: 27803700 PMCID: PMC5067535 DOI: 10.3389/fimmu.2016.00431] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2016] [Accepted: 10/03/2016] [Indexed: 12/20/2022] Open
Abstract
Pathogenic bacteria possess intricate regulatory networks that temporally control the production of virulence factors and enable the bacteria to survive and proliferate within host cell. Small non-coding RNAs (sRNAs) have been identified as important regulators of gene expression in diverse biological contexts. Recent research has shown bacterial sRNAs involved in growth and development, cell proliferation, differentiation, metabolism, cell signaling, and immune response through regulating protein–protein interactions or via their ability to base pair with RNA and DNA. In this review, we provide a brief overview of mechanism of action employed by immune-related sRNAs, their known functions in immunity, and how they can be integrated into regulatory circuits that govern virulence, which will facilitate our understanding of pathogenesis and the development of novel, more effective therapeutic approaches to treat infections caused by intracellular bacterial pathogens.
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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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38
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Mastroeni P, Rossi O. Immunology, epidemiology and mathematical modelling towards a better understanding of invasive non-typhoidal Salmonella disease and rational vaccination approaches. Expert Rev Vaccines 2016; 15:1545-1555. [PMID: 27171941 DOI: 10.1080/14760584.2016.1189330] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Invasive non-typhoidal Salmonella (iNTS) infections cause a high burden of lethal sepsis in young children and HIV patients, often associated with malaria, anaemia, malnutrition and sickle-cell disease. Vaccines against iNTS are urgently needed but none are licensed yet. Areas covered: This review illustrates how immunology, epidemiology and within-host pathogen behaviour affect invasive Salmonella infections and highlights how this knowledge can assist the improvement and choice of vaccines. Expert Commentary: Control of iNTS disease requires approaches that reduce transmission and improve diagnosis and treatment. These are often difficult to implement due to the fragile ecology and economies in endemic countries. Vaccines will be key tools in the fight against iNTS disease. To optimise vaccine design, we need to better define protective antigens and mechanisms of resistance to disease in susceptible populations even in those individuals where innate immunity may be impaired by widespread comorbidities.
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Affiliation(s)
- Pietro Mastroeni
- a Department of Veterinary Medicine , University of Cambridge , Cambridge , United Kingdom
| | - Omar Rossi
- a Department of Veterinary Medicine , University of Cambridge , Cambridge , United Kingdom
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39
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Kaiser P, Regoes RR, Hardt WD. Population Dynamics Analysis of Ciprofloxacin-Persistent S. Typhimurium Cells in a Mouse Model for Salmonella Diarrhea. Methods Mol Biol 2016; 1333:189-203. [PMID: 26468110 DOI: 10.1007/978-1-4939-2854-5_16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In vivo, antibiotics are often surprisingly inefficient at eliminating bacterial pathogens. In the case of ciprofloxacin therapy in a Salmonella enterica subspecies 1 serovar Typhimurium (S. Typhimurium, S. Tm) mouse infection model, this has been traced to tolerant bacterial cells surviving in lymph node monocytes (i.e., classical dendritic cells). To analyze the growth characteristics of these persisters, we have developed a population dynamics approach using mixtures of wild-type isogenic tagged strains (WITS) and a computational model. Here, we are providing a detailed description of the inoculum, the infection experiments, the computational analysis of the WITS data, and a computer simulation for assessing the quality of the growth parameters of the persistent S. Typhimurium cells. This approach is generic. It may be adapted to any organ infected and to any bacterial pathogen, provided that tools exist for generating, retrieving, and quantifying isogenic tagged strains.
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Affiliation(s)
- Patrick Kaiser
- Institute of Microbiology, D-BIOL, Eidgenössische Technische Hochschule ETH Zurich, Office HCI G417, Vladimir-Prelog-Weg 4, Zürich, 8093, Switzerland
| | - Roland R Regoes
- Institute of Integrative Biology, D-USYS, Eidgenössische Technische Hochschule ETH Zurich, CHN H76.2 Universitätsstr. 16, Zürich, 8092, Switzerland.
| | - Wolf-Dietrich Hardt
- Institute of Microbiology, D-BIOL, Eidgenössische Technische Hochschule ETH Zurich, Office HCI G417, Vladimir-Prelog-Weg 4, Zürich, 8093, Switzerland.
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40
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Goh YS, Armour KL, Clark MR, Grant AJ, Mastroeni P. Igg Subclasses Targeting the Flagella of Salmonella enterica Serovar Typhimurium Can Mediate Phagocytosis and Bacterial Killing. ACTA ACUST UNITED AC 2016; 7. [PMID: 27366588 DOI: 10.4172/2157-7560.1000322] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Invasive non-typhoidal Salmonella are a common cause of invasive disease in immuno-compromised individuals and in children. Multi-drug resistance poses challenges to disease control, with a critical need for effective vaccines. Flagellin is an attractive vaccine candidate due to surface exposure and high epitope copy number, but its potential as a target for opsonophacytic antibodies is unclear. We examined the effect of targeting flagella with different classes of IgG on the interaction between Salmonella Typhimurium and a human phagocyte-like cell line, THP-1. We tagged the FliC flagellar protein with a foreign CD52 mimotope (TSSPSAD) and bacteria were opsonized with a panel of humanised CD52 antibodies with the same antigen-binding V-region, but different constant regions. We found that IgG binding to flagella increases bacterial phagocytosis and reduces viable intracellular bacterial numbers. Opsonisation with IgG3, followed by IgG1, IgG4, and IgG2, resulted in the highest level of bacterial uptake and in the highest reduction in the intracellular load of viable bacteria. Taken together, our data provide proof-of-principle evidence that targeting flagella with antibodies can increase the antibacterial function of host cells, with IgG3 being the most potent subclass. These data will assist the rational design of urgently needed, optimised vaccines against iNTS disease.
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Affiliation(s)
- Yun Shan Goh
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom
| | - Kathryn L Armour
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, United Kingdom
| | - Michael R Clark
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, United Kingdom
| | - Andrew J Grant
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom
| | - Pietro Mastroeni
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom
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41
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Lei L, Wang W, Xia C, Liu F. Salmonella Virulence Factor SsrAB Regulated Factor Modulates Inflammatory Responses by Enhancing the Activation of NF-κB Signaling Pathway. THE JOURNAL OF IMMUNOLOGY 2015; 196:792-802. [PMID: 26673132 DOI: 10.4049/jimmunol.1500679] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 11/14/2015] [Indexed: 12/20/2022]
Abstract
Effector proteins encoded by Salmonella pathogenicity islands play a key role in promoting bacterial intracellular survival, colonization, and pathogenesis. In this study, we investigated the function of the virulence-associated effector SrfA (SsrAB regulated factor) both in macrophages in vitro and in infected mice in vivo. SrfA was secreted into the cytoplasm during S. Typhimurium infection and disassociated IL-1R-associated kinase-1 (IRAK-1) from the IRAK-1-Toll interacting protein (Tollip) complex by interacting with Tollip. The released IRAK-1 was phosphorylated and subsequently activated the NF-κB signaling pathway, which enhanced the LPS-induced expression of inflammatory cytokines, such as IL-8, IL-1β, and TNF-α. The coupling of ubiquitin to endoplasmic reticulum degradation aa 183-219 domain of Tollip is the binding region for SrfA, and both the MDaa207-226 and CTaa357-377 regions of SrfA mediate binding to Tollip and NF-κB signaling activation. Deletion of SrfA in S. Typhimurium had no notable effects on its replication but impaired the induction of NF-κB activation in infected macrophages. The mice infected with srfA-deficient bacteria exhibited a decreased inflammatory response and an increased survival rate compared with those infected with wild-type S. Typhimurium. We conclude that SrfA is a novel Salmonella virulence effector that helps modulate host inflammatory responses by promoting NF-κB signaling activation.
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Affiliation(s)
- Lei Lei
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China; and
| | - Wenbiao Wang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China; and
| | - Chuan Xia
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China; and
| | - Fenyong Liu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China; and Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, Berkeley, CA 94720
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Srikumar S, Kröger C, Hébrard M, Colgan A, Owen SV, Sivasankaran SK, Cameron ADS, Hokamp K, Hinton JCD. RNA-seq Brings New Insights to the Intra-Macrophage Transcriptome of Salmonella Typhimurium. PLoS Pathog 2015; 11:e1005262. [PMID: 26561851 PMCID: PMC4643027 DOI: 10.1371/journal.ppat.1005262] [Citation(s) in RCA: 184] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Accepted: 10/17/2015] [Indexed: 11/18/2022] Open
Abstract
Salmonella enterica serovar Typhimurium is arguably the world’s best-understood bacterial pathogen. However, crucial details about the genetic programs used by the bacterium to survive and replicate in macrophages have remained obscure because of the challenge of studying gene expression of intracellular pathogens during infection. Here, we report the use of deep sequencing (RNA-seq) to reveal the transcriptional architecture and gene activity of Salmonella during infection of murine macrophages, providing new insights into the strategies used by the pathogen to survive in a bactericidal immune cell. We characterized 3583 transcriptional start sites that are active within macrophages, and highlight 11 of these as candidates for the delivery of heterologous antigens from Salmonella vaccine strains. A majority (88%) of the 280 S. Typhimurium sRNAs were expressed inside macrophages, and SPI13 and SPI2 were the most highly expressed pathogenicity islands. We identified 31 S. Typhimurium genes that were strongly up-regulated inside macrophages but expressed at very low levels during in vitro growth. The SalComMac online resource allows the visualisation of every transcript expressed during bacterial replication within mammalian cells. This primary transcriptome of intra-macrophage S.-Typhimurium describes the transcriptional start sites and the transcripts responsible for virulence traits, and catalogues the sRNAs that may play a role in the regulation of gene expression during infection. The burden of Salmonellosis remains unacceptably high throughout the world and control measures have had limited success. Because Salmonella bacteria can be transmitted from the wider environment to animals and humans, the bacteria encounter diverse environments that include food, water, plant surfaces and the extracellular and intracellular phases of infection of eukaryotic hosts. An intricate transcriptional network has evolved to respond to a variety of environmental signals and control the “right time/ right place” expression of virulence genes. To understand how transcription is rewired during intracellular infection, we determined the primary transcriptome of Salmonella enterica serovar Typhimurium within murine macrophages. We report the coding genes, sRNAs and transcriptional start sites that are expressed within macrophages at 8 hours after infection, and use these to infer gene function. We identified gene promoters that are specifically expressed within macrophages and could drive the intracellular delivery of antigens by S. Typhimurium vaccine strains. These data contribute to our understanding of the mechanisms used by Salmonella to regulate virulence gene expression whilst replicating inside mammalian cells.
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Affiliation(s)
- Shabarinath Srikumar
- Department of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, Ireland
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Carsten Kröger
- Department of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, Ireland
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Magali Hébrard
- Department of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, Ireland
| | - Aoife Colgan
- Department of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, Ireland
| | - Siân V. Owen
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Sathesh K. Sivasankaran
- Department of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, Ireland
| | | | - Karsten Hokamp
- Department of Genetics, School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College, Dublin, Ireland
| | - Jay C. D. Hinton
- Department of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, Ireland
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
- * E-mail:
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43
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Barquist L, Vogel J. Accelerating Discovery and Functional Analysis of Small RNAs with New Technologies. Annu Rev Genet 2015; 49:367-94. [PMID: 26473381 DOI: 10.1146/annurev-genet-112414-054804] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Over the past decade, bacterial small RNAs (sRNAs) have gone from a biological curiosity to being recognized as a major class of regulatory molecules. High-throughput methods for sampling the transcriptional output of bacterial cells demonstrate that sRNAs are universal features of bacterial transcriptomes, are plentiful, and appear to vary extensively over evolutionary time. With ever more bacteria coming under study, the question becomes how can we accelerate the discovery and functional characterization of sRNAs in diverse organisms. New technologies built on high-throughput sequencing are emerging that can rapidly provide global insight into the numbers and functions of sRNAs in bacteria of interest, providing information that can shape hypotheses and guide research. In this review, we describe recent developments in transcriptomics (RNA-seq) and functional genomics that we expect to help us develop an integrated, systems-level view of sRNA biology in bacteria.
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Affiliation(s)
- Lars Barquist
- RNA Biology Group, Institute for Molecular Infection Biology, University of Würzburg, D-97080 Würzburg, Germany; ,
| | - Jörg Vogel
- RNA Biology Group, Institute for Molecular Infection Biology, University of Würzburg, D-97080 Würzburg, Germany; ,
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Gilchrist JJ, MacLennan CA, Hill AVS. Genetic susceptibility to invasive Salmonella disease. Nat Rev Immunol 2015; 15:452-63. [PMID: 26109132 DOI: 10.1038/nri3858] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Invasive Salmonella disease, in the form of enteric fever and invasive non-typhoidal Salmonella (iNTS) disease, causes substantial morbidity and mortality in children and adults in the developing world. The study of genetic variations in humans and mice that influence susceptibility of the host to Salmonella infection provides important insights into immunity to Salmonella. In this Review, we discuss data that have helped to elucidate the host genetic determinants of human enteric fever and iNTS disease, alongside data from the mouse model of Salmonella infection. Considered together, these studies provide a detailed picture of the immunobiology of human invasive Salmonella disease.
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Affiliation(s)
- James J Gilchrist
- Wellcome Trust Centre for Human Genetics, Roosevelt Drive, University of Oxford, Oxford OX3 7BN, UK
| | - Calman A MacLennan
- 1] Jenner Institute, Nuffield Department of Medicine, Old Road Campus Research Building, Roosevelt Drive, University of Oxford, Oxford, OX3 7DQ, UK. [2] Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Adrian V S Hill
- 1] Wellcome Trust Centre for Human Genetics, Roosevelt Drive, University of Oxford, Oxford OX3 7BN, UK. [2] Jenner Institute, Nuffield Department of Medicine, Old Road Campus Research Building, Roosevelt Drive, University of Oxford, Oxford, OX3 7DQ, UK
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45
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Orf K, Cunnington AJ. Infection-related hemolysis and susceptibility to Gram-negative bacterial co-infection. Front Microbiol 2015; 6:666. [PMID: 26175727 PMCID: PMC4485309 DOI: 10.3389/fmicb.2015.00666] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 06/18/2015] [Indexed: 01/05/2023] Open
Abstract
Increased susceptibility to co-infection with enteric Gram-negative bacteria, particularly non-typhoidal Salmonella, is reported in malaria and Oroya fever (Bartonella bacilliformis infection), and can lead to increased mortality. Accumulating epidemiological evidence indicates a causal association with risk of bacterial co-infection, rather than just co-incidence of common risk factors. Both malaria and Oroya fever are characterized by hemolysis, and observations in humans and animal models suggest that hemolysis causes the susceptibility to bacterial co-infection. Evidence from animal models implicates hemolysis in the impairment of a variety of host defense mechanisms, including macrophage dysfunction, neutrophil dysfunction, and impairment of adaptive immune responses. One mechanism supported by evidence from animal models and human data, is the induction of heme oxygenase-1 in bone marrow, which impairs the ability of developing neutrophils to mount a competent oxidative burst. As a result, dysfunctional neutrophils become a new niche for replication of intracellular bacteria. Here we critically appraise and summarize the key evidence for mechanisms which may contribute to these very specific combinations of co-infections, and propose interventions to ameliorate this risk.
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Affiliation(s)
- Katharine Orf
- Section of Paediatrics, Imperial College London London, UK
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46
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Korhonen TK. Fibrinolytic and procoagulant activities of Yersinia pestis and Salmonella enterica. J Thromb Haemost 2015; 13 Suppl 1:S115-20. [PMID: 26149012 DOI: 10.1111/jth.12932] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Pla of the plague bacterium Yersinia pestis and PgtE of the enteropathogen Salmonella enterica are surface-exposed, transmembrane β-barrel proteases of the omptin family that exhibit a complex array of interactions with the hemostatic systems in vitro, and both proteases are established virulence factors. Pla favors fibrinolysis by direct activation of plasminogen, inactivation of the serpins plasminogen activator inhibitor-1 and α2-antiplasmin, inactivation of the thrombin-activable fibrinolysis inhibitor, and activation of single-chain urokinase. PgtE is structurally very similar but exhibits partially different functions and differ in expression control. PgtE proteolysis targets control aspects of fibrinolysis, and mimicry of matrix metalloproteinases enhances cell migration that should favor the intracellular spread of the bacterium. Enzymatic activity of both proteases is strongly influenced by the environment-induced variations in lipopolysaccharide that binds to the β-barrel. Both proteases cleave the tissue factor pathway inhibitor and thus also express procoagulant activity.
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Affiliation(s)
- T K Korhonen
- General Microbiology, Department of Biosciences, University of Helsinki, Helsinki, Finland
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Distinct type I and type II toxin-antitoxin modules control Salmonella lifestyle inside eukaryotic cells. Sci Rep 2015; 5:9374. [PMID: 25792384 PMCID: PMC4366850 DOI: 10.1038/srep09374] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 03/02/2015] [Indexed: 02/02/2023] Open
Abstract
Toxin-antitoxin (TA) modules contribute to the generation of non-growing cells in response to stress. These modules abound in bacterial pathogens although the bases for this profusion remain largely unknown. Using the intracellular bacterial pathogen Salmonella enterica serovar Typhimurium as a model, here we show that a selected group of TA modules impact bacterial fitness inside eukaryotic cells. We characterized in this pathogen twenty-seven TA modules, including type I and type II TA modules encoding antisense RNA and proteinaceous antitoxins, respectively. Proteomic and gene expression analyses revealed that the pathogen produces numerous toxins of TA modules inside eukaryotic cells. Among these, the toxins HokST, LdrAST, and TisBST, encoded by type I TA modules and T4ST and VapC2ST, encoded by type II TA modules, promote bacterial survival inside fibroblasts. In contrast, only VapC2ST shows that positive effect in bacterial fitness when the pathogen infects epithelial cells. These results illustrate how S. Typhimurium uses distinct type I and type II TA modules to regulate its intracellular lifestyle in varied host cell types. This function specialization might explain why the number of TA modules increased in intracellular bacterial pathogens.
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Toll-Like receptor 2 (TLR2) and TLR9 play opposing roles in host innate immunity against Salmonella enterica serovar Typhimurium infection. Infect Immun 2015; 83:1641-9. [PMID: 25667264 DOI: 10.1128/iai.02870-14] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Toll-like receptors (TLRs) are evolutionarily conserved host proteins that are essential for effective host defense against pathogens. However, recent studies suggest that some TLRs can negatively regulate immune responses. We observed here that TLR2 and TLR9 played opposite roles in regulating innate immunity against oral infection of Salmonella enterica serovar Typhimurium in mice. While TLR9-/- mice exhibited shortened survival, an increased cytokine storm, and more severe Salmonella hepatitis than wild-type (WT) mice, TLR2-/- mice exhibited the opposite phenomenon. Further studies demonstrated that TLR2 deficiency and TLR9 deficiency in macrophages both disrupted NK cell cytotoxicity against S. Typhimurium-infected macrophages by downregulating NK cell degranulation and gamma interferon (IFN-γ) production through decreased macrophage expression of the RAE-1 NKG2D ligand. But more importantly, we found that S. Typhimurium-infected TLR2-/- macrophages upregulated inducible nitric oxide synthase (iNOS) expression, resulting in a lower bacterial load than that in WT macrophages in vitro and livers in vivo as well as low proinflammatory cytokine levels. In contrast, TLR9-/- macrophages showed decreased reactive oxygen species (ROS) expression concomitant with a high bacterial load in the macrophages and in livers of TLR9-/- mice. TLR9-/- macrophages were also more susceptible than WT macrophages to S. Typhimurium-induced necroptosis in vitro, likely contributing to bacterial spread and transmission in vivo. Collectively, these findings indicate that TLR2 negatively regulates anti-S. Typhimurium immunity, whereas TLR9 is vital to host defense and survival against S. Typhimurium invasion. TLR2 antagonists or TLR9 agonists may thus serve as potential anti-S. Typhimurium therapeutic agents.
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Riva R, Korhonen TK, Meri S. The outer membrane protease PgtE of Salmonella enterica interferes with the alternative complement pathway by cleaving factors B and H. Front Microbiol 2015; 6:63. [PMID: 25705210 PMCID: PMC4319491 DOI: 10.3389/fmicb.2015.00063] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 01/18/2015] [Indexed: 11/21/2022] Open
Abstract
The virulence factor PgtE is an outer membrane protease (omptin) of the zoonotic pathogen Salmonella enterica that causes diseases ranging from gastroenteritis to severe enteric fever. It is surface exposed in bacteria that have a short-chain, i.e., rough LPS, as observed e.g., in bacteria residing inside macrophages or just emerging from them. We investigated whether PgtE cleaves the complement factors B (B) and H (H), key proteins controlling formation and inactivation of the complement protein C3b and thereby the activity of the complement system. S. enterica serovar Typhimurium or omptin-expressing recombinant E. coli bacteria were incubated with purified human complement proteins or recombinant H fragments. PgtE cleaved both B and H, whereas its close homolog Pla of Yersinia pestis cleaved only H. H was cleaved at both N- and C-termini, while the central region resisted proteolysis. Because of multiple effects of PgtE on complement components (cleavage of C3, C3b, B, and H) we assessed its effect on the opsonophagocytosis of Salmonella. In human serum, C3 cleavage was dependent on proteolytically active PgtE. Human neutrophils interacted less with serum-opsonized FITC-stained S. enterica 14028R than with the isogenic ΔpgtE strain, as analyzed by flow cytometry. In conclusion, cleavage of B and H by PgtE, together with C3 cleavage, affects the C3-mediated recognition of S. enterica by human neutrophils, thus thwarting the immune protection against Salmonella.
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Affiliation(s)
- Rauna Riva
- Immunobiology Research Program, Research Program Unit, University of HelsinkiHelsinki, Finland
- Department of Bacteriology and Immunology, Haartman Institute, University of HelsinkiHelsinki, Finland
| | - Timo K. Korhonen
- General Microbiology, Department of Biosciences, University of HelsinkiHelsinki, Finland
| | - Seppo Meri
- Immunobiology Research Program, Research Program Unit, University of HelsinkiHelsinki, Finland
- Department of Bacteriology and Immunology, Haartman Institute, University of HelsinkiHelsinki, Finland
- HUSLAB, Hospital District of Helsinki and UusimaaHelsinki, Finland
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50
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MacLennan CA. Antibodies and protection against invasive salmonella disease. Front Immunol 2014; 5:635. [PMID: 25566248 PMCID: PMC4273658 DOI: 10.3389/fimmu.2014.00635] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 11/27/2014] [Indexed: 11/29/2022] Open
Affiliation(s)
- Calman A MacLennan
- Novartis Vaccines Institute for Global Health , Siena , Italy ; School of Immunity and Infection, College of Medicine and Dental Sciences, University of Birmingham , Birmingham , UK
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