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Scharte F, Franzkoch R, Hensel M. Flagella-mediated cytosolic motility of Salmonella enterica Paratyphi A aids in evasion of xenophagy but does not impact egress from host cells. Mol Microbiol 2024; 121:413-430. [PMID: 37278220 DOI: 10.1111/mmi.15104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 05/19/2023] [Accepted: 05/23/2023] [Indexed: 06/07/2023]
Abstract
Salmonella enterica is a common foodborne, facultative intracellular enteropathogen. Typhoidal serovars like Paratyphi A (SPA) are human restricted and cause severe systemic diseases, while many serovars like Typhimurium (STM) have a broad host range, and usually lead to self-limiting gastroenteritis. There are key differences between typhoidal and non-typhoidal Salmonella in pathogenesis, but underlying mechanisms remain largely unknown. Transcriptomes and phenotypes in epithelial cells revealed induction of motility, flagella and chemotaxis genes for SPA but not STM. SPA exhibited cytosolic motility mediated by flagella. In this study, we applied single-cell microscopy to analyze triggers and cellular consequences of cytosolic motility. Live-cell imaging (LCI) revealed that SPA invades host cells in a highly cooperative manner. Extensive membrane ruffling at invasion sites led to increased membrane damage in nascent Salmonella-containing vacuole, and subsequent cytosolic release. After release into the cytosol, motile bacteria showed the same velocity as under culture conditions in media. Reduced capture of SPA by autophagosomal membranes was observed by LCI and electron microscopy. Prior work showed that SPA does not use flagella-mediated motility for cell exit via the intercellular spread. However, cytosolic motile SPA was invasion-primed if released from host cells. Our results reveal flagella-mediated cytosolic motility as a possible xenophagy evasion mechanism that could drive disease progression and contributes to the dissemination of systemic infection.
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Affiliation(s)
- Felix Scharte
- Abteilung Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
| | - Rico Franzkoch
- Abteilung Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
- Universität Osnabrück, iBiOs-Integrated Bioimaging Facility, Osnabrück, Germany
| | - Michael Hensel
- Abteilung Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
- Universität Osnabrück, CellNanOs-Center of Cellular Nanoanalytics, Osnabrück, Germany
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2
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Han J, Aljahdali N, Zhao S, Tang H, Harbottle H, Hoffmann M, Frye JG, Foley SL. Infection biology of Salmonella enterica. EcoSal Plus 2024:eesp00012023. [PMID: 38415623 DOI: 10.1128/ecosalplus.esp-0001-2023] [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: 02/17/2023] [Accepted: 07/31/2023] [Indexed: 02/29/2024]
Abstract
Salmonella enterica is the leading cause of bacterial foodborne illness in the USA, with an estimated 95% of salmonellosis cases due to the consumption of contaminated food products. Salmonella can cause several different disease syndromes, with the most common being gastroenteritis, followed by bacteremia and typhoid fever. Among the over 2,600 currently identified serotypes/serovars, some are mostly host-restricted and host-adapted, while the majority of serotypes can infect a broader range of host species and are associated with causing both livestock and human disease. Salmonella serotypes and strains within serovars can vary considerably in the severity of disease that may result from infection, with some serovars that are more highly associated with invasive disease in humans, while others predominantly cause mild gastroenteritis. These observed clinical differences may be caused by the genetic make-up and diversity of the serovars. Salmonella virulence systems are very complex containing several virulence-associated genes with different functions that contribute to its pathogenicity. The different clinical syndromes are associated with unique groups of virulence genes, and strains often differ in the array of virulence traits they display. On the chromosome, virulence genes are often clustered in regions known as Salmonella pathogenicity islands (SPIs), which are scattered throughout different Salmonella genomes and encode factors essential for adhesion, invasion, survival, and replication within the host. Plasmids can also carry various genes that contribute to Salmonella pathogenicity. For example, strains from several serovars associated with significant human disease, including Choleraesuis, Dublin, Enteritidis, Newport, and Typhimurium, can carry virulence plasmids with genes contributing to attachment, immune system evasion, and other roles. The goal of this comprehensive review is to provide key information on the Salmonella virulence, including the contributions of genes encoded in SPIs and plasmids during Salmonella pathogenesis.
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Affiliation(s)
- Jing Han
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA
| | - Nesreen Aljahdali
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA
- Biological Science Department, College of Science, King Abdul-Aziz University, Jeddah, Saudi Arabia
| | - Shaohua Zhao
- Center for Veterinary Medicine, U.S. Food and Drug Administration, Rockville, Maryland, USA
| | - Hailin Tang
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA
| | - Heather Harbottle
- Center for Veterinary Medicine, U.S. Food and Drug Administration, Rockville, Maryland, USA
| | - Maria Hoffmann
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, College Park, Maryland, USA
| | - Jonathan G Frye
- Agricutlutral Research Service, U.S. Department of Agriculture, Athens, Georgia, USA
| | - Steven L Foley
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA
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3
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Park S, Cho E, Senevirathne A, Chung HJ, Ha S, Kim CH, Kang S, Lee JH. Salmonella vector induces protective immunity against Lawsonia and Salmonella in murine model using prokaryotic expression system. J Vet Sci 2024; 25:e4. [PMID: 38311319 PMCID: PMC10839175 DOI: 10.4142/jvs.23219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 11/18/2023] [Accepted: 11/24/2023] [Indexed: 02/07/2024] Open
Abstract
BACKGROUND Lawsonia intracellularis is the causative agent of proliferative enteropathy and is associated with several outbreaks, causing substantial economic loss to the porcine industry. OBJECTIVES In this study, we focused on demonstrating the protective effect in the mouse model through the immunological bases of two vaccine strains against porcine proliferative enteritis. METHODS We used live-attenuated Salmonella Typhimurium (ST) secreting two selected immunogenic LI antigens (Lawsonia autotransporter A epitopes and flagellin [FliC]-peptidoglycan-associated lipoprotein-FliC) as the vaccine carrier. The constructs were cloned into a Salmonella expression vector (pJHL65) and transformed into the ST strain (JOL912). The expression of immunogenic proteins within Salmonella was evaluated via immunoblotting. RESULTS Immunizing BALB/c mice orally and subcutaneously induced high levels of LI-specific systemic immunoglobulin G and mucosal secretory immunoglobulin A. In immunized mice, there was significant upregulation of interferon-γ and interleukin-4 cytokine mRNA and an increase in the subpopulations of cluster of differentiation (CD) 4+ and CD 8+ T lymphocytes upon splenocytes re-stimulation with LI antigens. We observed significant protection in C57BL/6 mice against challenge with 106.9 times the median tissue culture infectious dose of LI or 2 × 109 colony-forming units of the virulent ST strain. Immunizing mice with either individual vaccine strains or co-mixture inhibited bacterial proliferation, with a marked reduction in the percentage of mice shedding Lawsonia in their feces. CONCLUSIONS Salmonella-mediated LI gene delivery induces robust humoral and cellular immune reactions, leading to significant protection against LI and salmonellosis.
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Affiliation(s)
- Sungwoo Park
- College of Veterinary Medicine, Jeonbuk National University, Iksan Campus, Iksan 54596, Korea
- Swine Science Division, National Institute of Animal Science, Cheonan 31000, Korea
| | - Eunseok Cho
- Swine Science Division, National Institute of Animal Science, Cheonan 31000, Korea
| | - Amal Senevirathne
- College of Veterinary Medicine, Jeonbuk National University, Iksan Campus, Iksan 54596, Korea
- College of Veterinary Medicine and Research Institute of Veterinary Medicine, Chungnam National University, Daejeon 34134, Korea
| | - Hak-Jae Chung
- Swine Science Division, National Institute of Animal Science, Cheonan 31000, Korea
| | - Seungmin Ha
- Dairy Science Division, National Institute of Animal Science, Cheonan 31000, Korea
| | - Chae-Hyun Kim
- Swine Science Division, National Institute of Animal Science, Cheonan 31000, Korea
| | - Seogjin Kang
- Dairy Science Division, National Institute of Animal Science, Cheonan 31000, Korea.
| | - John Hwa Lee
- College of Veterinary Medicine, Jeonbuk National University, Iksan Campus, Iksan 54596, Korea.
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4
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Worley MJ. Salmonella Bloodstream Infections. Trop Med Infect Dis 2023; 8:487. [PMID: 37999606 PMCID: PMC10675298 DOI: 10.3390/tropicalmed8110487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 10/23/2023] [Accepted: 10/24/2023] [Indexed: 11/25/2023] Open
Abstract
Salmonella is a major foodborne pathogen of both animals and humans. This bacterium is responsible for considerable morbidity and mortality world-wide. Different serovars of this genus cause diseases ranging from self-limiting gastroenteritis to a potentially fatal systemic disease known as enteric fever. Gastrointestinal infections with Salmonella are usually self-limiting and rarely require medical intervention. Bloodstream infections, on the other hand, are often fatal even with hospitalization. This review describes the routes and underlying mechanisms of the extraintestinal dissemination of Salmonella and the chronic infections that sometimes result. It includes information on the pathogenicity islands and individual virulence factors involved in systemic dissemination as well as a discussion of the host factors that mediate susceptibility. Also, the major outbreaks of invasive Salmonella disease in the tropics are described.
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Affiliation(s)
- Micah J Worley
- Department of Biology, University of Louisville, Louisville, KY 40292, USA
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5
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Hamblin M, Schade R, Narasimhan R, Monack DM. Salmonella enterica serovar Typhi uses two type 3 secretion systems to replicate in human macrophages and colonize humanized mice. mBio 2023; 14:e0113723. [PMID: 37341487 PMCID: PMC10470537 DOI: 10.1128/mbio.01137-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 05/04/2023] [Indexed: 06/22/2023] Open
Abstract
Salmonella enterica serovar Typhi (S. Typhi) is a human-restricted pathogen that replicates in macrophages. In this study, we investigated the roles of the S. Typhi type 3 secretion systems (T3SSs) encoded on Salmonella pathogenicity islands (SPI)-1 (T3SS-1) and SPI-2 (T3SS-2) during human macrophage infection. We found that mutants of S. Typhi deficient for both T3SSs were defective for intramacrophage replication as measured by flow cytometry, viable bacterial counts, and live time-lapse microscopy. T3SS-secreted proteins PipB2 and SifA contributed to S. Typhi replication and were translocated into the cytosol of human macrophages through both T3SS-1 and T3SS-2, demonstrating functional redundancy for these secretion systems. Importantly, an S. Typhi mutant strain that is deficient for both T3SS-1 and T3SS-2 was severely attenuated in the ability to colonize systemic tissues in a humanized mouse model of typhoid fever. Overall, this study establishes a critical role for S. Typhi T3SSs during its replication within human macrophages and during systemic infection of humanized mice. IMPORTANCE Salmonella enterica serovar Typhi is a human-restricted pathogen that causes typhoid fever. Understanding the key virulence mechanisms that facilitate S. Typhi replication in human phagocytes will enable rational vaccine and antibiotic development to limit the spread of this pathogen. While S. Typhimurium replication in murine models has been studied extensively, there is limited information available about S. Typhi replication in human macrophages, some of which directly conflict with findings from S. Typhimurium murine models. This study establishes that both of S. Typhi's two type 3 secretion systems (T3SS-1 and T3SS-2) contribute to intramacrophage replication and virulence.
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Affiliation(s)
- Meagan Hamblin
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Ruth Schade
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Ramya Narasimhan
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Denise M. Monack
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
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6
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Hamblin M, Schade R, Narasimhan R, Monack DM. Salmonella enterica serovar Typhi uses two type 3 secretion systems to replicate in human macrophages and to colonize humanized mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.06.543980. [PMID: 37333307 PMCID: PMC10274799 DOI: 10.1101/2023.06.06.543980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Salmonella enterica serovar Typhi ( S. Typhi) is a human-restricted pathogen that replicates in macrophages. In this study, we investigated the roles of the S. Typhi Type 3 secretion systems (T3SSs) encoded on Salmonella Pathogenicity Islands (SPI) -1 (T3SS-1) and -2 (T3SS-2) during human macrophage infection. We found that mutants of S . Typhi deficient for both T3SSs were defective for intramacrophage replication as measured by flow cytometry, viable bacterial counts, and live time-lapse microscopy. T3SS-secreted proteins PipB2 and SifA contributed to S. Typhi replication and were translocated into the cytosol of human macrophages through both T3SS-1 and -2, demonstrating functional redundancy for these secretion systems. Importantly, an S . Typhi mutant strain that is deficient for both T3SS-1 and -2 was severely attenuated in the ability to colonize systemic tissues in a humanized mouse model of typhoid fever. Overall, this study establishes a critical role for S. Typhi T3SSs during its replication within human macrophages and during systemic infection of humanized mice. Importance Salmonella enterica serovar Typhi is a human-restricted pathogen that causes typhoid fever. Understanding the key virulence mechanisms that facilitate S. Typhi replication in human phagocytes will enable rational vaccine and antibiotic development to limit spread of this pathogen. While S. Typhimurium replication in murine models has been studied extensively, there is limited information available about S. Typhi replication in human macrophages, some of which directly conflicts with findings from S. Typhimurium murine models. This study establishes that both of S. Typhi's two Type 3 Secretion Systems (T3SS-1 and -2) contribute to intramacrophage replication and virulence.
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7
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Pillay TD, Hettiarachchi SU, Gan J, Diaz-Del-Olmo I, Yu XJ, Muench JH, Thurston TL, Pearson JS. Speaking the host language: how Salmonella effector proteins manipulate the host. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001342. [PMID: 37279149 PMCID: PMC10333799 DOI: 10.1099/mic.0.001342] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Accepted: 05/10/2023] [Indexed: 06/08/2023]
Abstract
Salmonella injects over 40 virulence factors, termed effectors, into host cells to subvert diverse host cellular processes. Of these 40 Salmonella effectors, at least 25 have been described as mediating eukaryotic-like, biochemical post-translational modifications (PTMs) of host proteins, altering the outcome of infection. The downstream changes mediated by an effector's enzymatic activity range from highly specific to multifunctional, and altogether their combined action impacts the function of an impressive array of host cellular processes, including signal transduction, membrane trafficking, and both innate and adaptive immune responses. Salmonella and related Gram-negative pathogens have been a rich resource for the discovery of unique enzymatic activities, expanding our understanding of host signalling networks, bacterial pathogenesis as well as basic biochemistry. In this review, we provide an up-to-date assessment of host manipulation mediated by the Salmonella type III secretion system injectosome, exploring the cellular effects of diverse effector activities with a particular focus on PTMs and the implications for infection outcomes. We also highlight activities and functions of numerous effectors that remain poorly characterized.
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Affiliation(s)
- Timesh D. Pillay
- Centre for Bacterial Resistance Biology, Department of Infectious Disease, Imperial College, London SW7 2AZ, UK
- The Francis Crick Institute, London NW1 1AT, UK
| | - Sahampath U. Hettiarachchi
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Jiyao Gan
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Ines Diaz-Del-Olmo
- Centre for Bacterial Resistance Biology, Department of Infectious Disease, Imperial College, London SW7 2AZ, UK
| | - Xiu-Jun Yu
- Centre for Bacterial Resistance Biology, Department of Infectious Disease, Imperial College, London SW7 2AZ, UK
| | - Janina H. Muench
- Centre for Bacterial Resistance Biology, Department of Infectious Disease, Imperial College, London SW7 2AZ, UK
- The Francis Crick Institute, London NW1 1AT, UK
| | - Teresa L.M. Thurston
- Centre for Bacterial Resistance Biology, Department of Infectious Disease, Imperial College, London SW7 2AZ, UK
- The Francis Crick Institute, London NW1 1AT, UK
| | - Jaclyn S. Pearson
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
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8
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Wang BX, Butler DS, Hamblin M, Monack DM. One species, different diseases: the unique molecular mechanisms that underlie the pathogenesis of typhoidal Salmonella infections. Curr Opin Microbiol 2023; 72:102262. [PMID: 36640585 PMCID: PMC10023398 DOI: 10.1016/j.mib.2022.102262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 12/07/2022] [Accepted: 12/16/2022] [Indexed: 01/15/2023]
Abstract
Salmonella enterica is one of the most widespread bacterial pathogens found worldwide, resulting in approximately 100 million infections and over 200 000 deaths per year. Salmonella isolates, termed 'serovars', can largely be classified as either nontyphoidal or typhoidal Salmonella, which differ in regard to disease manifestation and host tropism. Nontyphoidal Salmonella causes gastroenteritis in many hosts, while typhoidal Salmonella is human-restricted and causes typhoid fever, a systemic disease with a mortality rate of up to 30% without treatment. There has been considerable interest in understanding how different Salmonella serovars cause different diseases, but the molecular details that underlie these infections have not yet been fully characterized, especially in the case of typhoidal Salmonella. In this review, we highlight the current state of research into understanding the pathogenesis of both nontyphoidal and typhoidal Salmonella, with a specific interest in serovar-specific traits that allow human-adapted strains of Salmonella to cause enteric fever. Overall, a more detailed molecular understanding of how different Salmonella isolates infect humans will provide critical insights into how we can eradicate these dangerous enteric pathogens.
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Affiliation(s)
- Benjamin X Wang
- Department of Microbiology & Immunology, Stanford University, Stanford, CA, USA
| | - Daniel Sc Butler
- Department of Microbiology & Immunology, Stanford University, Stanford, CA, USA
| | - Meagan Hamblin
- Department of Microbiology & Immunology, Stanford University, Stanford, CA, USA
| | - Denise M Monack
- Department of Microbiology & Immunology, Stanford University, Stanford, CA, USA.
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9
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Cappable-Seq Reveals Specific Patterns of Metabolism and Virulence for Salmonella Typhimurium Intracellular Survival within Acanthamoeba castellanii. Int J Mol Sci 2021; 22:ijms22169077. [PMID: 34445780 PMCID: PMC8396566 DOI: 10.3390/ijms22169077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 08/16/2021] [Accepted: 08/19/2021] [Indexed: 01/21/2023] Open
Abstract
The bacterial pathogen Salmonella enterica, which causes enteritis, has a broad host range and extensive environmental longevity. In water and soil, Salmonella interacts with protozoa and multiplies inside their phagosomes. Although this relationship resembles that between Salmonella and mammalian phagocytes, the interaction mechanisms and bacterial genes involved are unclear. Here, we characterized global gene expression patterns of S. enterica serovar Typhimurium within Acanthamoeba castellanii at the early stage of infection by Cappable-Seq. Gene expression features of S. Typhimurium within A. castellanii were presented with downregulation of glycolysis-related, and upregulation of glyoxylate cycle-related genes. Expression of Salmonella Pathogenicity Island-1 (SPI-1), chemotaxis system, and flagellar apparatus genes was upregulated. Furthermore, expression of genes mediating oxidative stress response and iron uptake was upregulated within A. castellanii as well as within mammalian phagocytes. Hence, global S. Typhimurium gene expression patterns within A. castellanii help better understand the molecular mechanisms of Salmonella adaptation to an amoeba cell and intracellular persistence in protozoa inhabiting water and soil ecosystems.
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10
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The zinc transporter ZnuABC is critical for the virulence of Chromobacterium violaceum and contributes to diverse zinc-dependent physiological processes. Infect Immun 2021; 89:e0031121. [PMID: 34370507 DOI: 10.1128/iai.00311-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chromobacterium violaceum is a ubiquitous environmental bacterium that causes sporadic life-threatening infections in humans. How C. violaceum acquires zinc to colonize environmental and host niches is unknown. In this work, we demonstrated that C. violaceum employs the zinc uptake system ZnuABC to overcome zinc limitation in the host, ensuring the zinc supply for several physiological demands. Our data indicated that the C. violaceum ZnuABC transporter is encoded in a zur-CV_RS15045-CV_RS15040-znuCBA operon. This operon was repressed by the zinc uptake regulator Zur and derepressed in the presence of the host protein calprotectin (CP) and the synthetic metal chelator EDTA. A ΔznuCBA mutant strain showed impaired growth under these zinc-chelated conditions. Moreover, the deletion of znuCBA provoked a reduction in violacein production, swimming motility, biofilm formation, and bacterial competition. Remarkably, the ΔznuCBA mutant strain was highly attenuated for virulence in an in vivo mouse infection model and showed a low capacity to colonize the liver, grow in the presence of CP, and resist neutrophil killing. Overall, our findings demonstrate that ZnuABC is essential for C. violaceum virulence, contributing to subvert the zinc-based host nutritional immunity.
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11
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Hussain S, Ouyang P, Zhu Y, Khalique A, He C, Liang X, Shu G, Yin L. Type 3 secretion system 1 of Salmonella typhimurium and its inhibitors: a novel strategy to combat salmonellosis. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:34154-34166. [PMID: 33966165 DOI: 10.1007/s11356-021-13986-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 04/13/2021] [Indexed: 06/12/2023]
Abstract
Unsuccessful vaccination against Salmonella due to a large number of serovars, and antibiotic resistance, necessitates the development of novel therapeutics to treat salmonellosis. The development of anti-virulence agents against multi-drug-resistant bacteria is a novel strategy because of its non-bacterial feature. Hence, a thorough study of the type three secretion system (T3SS) of Salmonella would help us better understand its role in bacterial pathogenesis and development of anti-virulence agents. However, T3SS can be inhibited by different chemicals at different stages of infection and sequenced delivery of effectors can be blocked to restrict the progression of disease. This review highlights the role of T3SS-1 in the internalization, survival, and replication of Salmonella within the intestinal epithelium and T3SS inhibitors. We concluded that the better we understand the structures and functions of T3SS, the more we have chances to develop anti-virulence agents. Furthermore, greater insights into the T3SS inhibitors of Salmonella would help in the mitigation of the antibiotic resistance problem and would lead us to the era of new therapeutics against salmonellosis.
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Affiliation(s)
- Sajjad Hussain
- College of Veterinary Medicine, Sichuan Agriculture University, Huimin Road 211, Wenjiang, Chengdu, China
| | - Ping Ouyang
- College of Veterinary Medicine, Sichuan Agriculture University, Huimin Road 211, Wenjiang, Chengdu, China
| | - Yingkun Zhu
- College of Veterinary Medicine, Sichuan Agriculture University, Huimin Road 211, Wenjiang, Chengdu, China
| | - Abdul Khalique
- College of Veterinary Medicine, Sichuan Agriculture University, Huimin Road 211, Wenjiang, Chengdu, China
| | - Changliang He
- College of Veterinary Medicine, Sichuan Agriculture University, Huimin Road 211, Wenjiang, Chengdu, China
| | - Xiaoxia Liang
- College of Veterinary Medicine, Sichuan Agriculture University, Huimin Road 211, Wenjiang, Chengdu, China
| | - Gang Shu
- College of Veterinary Medicine, Sichuan Agriculture University, Huimin Road 211, Wenjiang, Chengdu, China
| | - Lizi Yin
- College of Veterinary Medicine, Sichuan Agriculture University, Huimin Road 211, Wenjiang, Chengdu, China.
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12
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Schultz BM, Melo-Gonzalez F, Salazar GA, Porto BN, Riedel CA, Kalergis AM, Bueno SM. New Insights on the Early Interaction Between Typhoid and Non-typhoid Salmonella Serovars and the Host Cells. Front Microbiol 2021; 12:647044. [PMID: 34276584 PMCID: PMC8282409 DOI: 10.3389/fmicb.2021.647044] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 06/08/2021] [Indexed: 11/13/2022] Open
Abstract
Salmonella enterica is a common source of food and water-borne infections, causing a wide range of clinical ailments in both human and animal hosts. Immunity to Salmonella involves an interplay between different immune responses, which are rapidly initiated to control bacterial burden. However, Salmonella has developed several strategies to evade and modulate the host immune responses. In this sense, the main knowledge about the pathogenicity of this bacterium has been obtained by the study of mouse models with non-typhoidal serovars. However, this knowledge is not representative of all the pathologies caused by non-typhoidal serovars in the human. Here we review the most important features of typhoidal and non-typhoidal serovars and the diseases they cause in the human host, describing the virulence mechanisms used by these pathogens that have been identified in different models of infection.
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Affiliation(s)
- Bárbara M Schultz
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Felipe Melo-Gonzalez
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Geraldyne A Salazar
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Bárbara N Porto
- Laboratory of Clinical and Experimental Immunology, School of Medicine, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil.,Program in Translational Medicine, Hospital for Sick Children, Toronto, ON, Canada
| | - Claudia A Riedel
- Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Millennium Institute on Immunology and Immunotherapy, Universidad Andrés Bello, Santiago, Chile
| | - Alexis M Kalergis
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Endocrinología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Susan M Bueno
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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13
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Zarkani AA, Schikora A. Mechanisms adopted by Salmonella to colonize plant hosts. Food Microbiol 2021; 99:103833. [PMID: 34119117 DOI: 10.1016/j.fm.2021.103833] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 11/16/2022]
Abstract
Fruits and vegetables consumed fresh or as minimally-processed produce, have multiple benefits for our diet. Unfortunately, they bring a risk of food-borne diseases, for example salmonellosis. Interactions between Salmonella and crop plants are indeed a raising concern for the global health. Salmonella uses multiple strategies to manipulate the host defense system, including plant's defense responses. The main focus of this review are strategies used by this bacterium during the interaction with crop plants. Emphasis was put on how Salmonella avoids the plant defense responses and successfully colonizes plants. In addition, several factors were reviewed assessing their impact on Salmonella persistence and physiological adaptation to plants and plant-related environment. The understanding of those mechanisms, their regulation and use by the pathogen, while in contact with plants, has significant implication on the growth, harvest and processing steps in plant production system. Consequently, it requires both the authorities and science to advance and definite methods aiming at prevention of crop plants contamination. Thus, minimizing and/or eliminating the potential of human diseases.
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Affiliation(s)
- Azhar A Zarkani
- Julius Kühn Institute (JKI) - Federal Research Centre for Cultivated Plants, Institute for Epidemiology and Pathogen Diagnostics, Messeweg 11/12, 38104, Braunschweig, Germany; University of Baghdad, Department of Biotechnology, 10071, Baghdad, Iraq.
| | - Adam Schikora
- Julius Kühn Institute (JKI) - Federal Research Centre for Cultivated Plants, Institute for Epidemiology and Pathogen Diagnostics, Messeweg 11/12, 38104, Braunschweig, Germany.
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14
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Shin E, Park J, Jeong HJ, Park AK, Na K, Lee H, Chun JH, Hwang KJ, Kim CJ, Kim J. Emerging high-level ciprofloxacin-resistant Salmonella enterica serovar typhi haplotype H58 in travelers returning to the Republic of Korea from India. PLoS Negl Trop Dis 2021; 15:e0009170. [PMID: 33651791 PMCID: PMC7987170 DOI: 10.1371/journal.pntd.0009170] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 03/23/2021] [Accepted: 01/22/2021] [Indexed: 11/19/2022] Open
Abstract
In Korea, typhoid fever is a rare disease due to improved living standards. However, typhoid fever remains a major burden in developing countries and regions, such as India and Southeast Asia. In this study, we isolated Salmonella Typhi (S. Typhi) from eight patients with typhoid fever who were travelers returning from India. The strains isolated were characterized by antimicrobial susceptibility profiling and whole-genome sequencing (WGS) analysis. All strains were resistant to nalidixic acid and azithromycin. Among them, four isolates were highly resistant to ciprofloxacin (MIC ≥32 μg/ml); these strains have not been confirmed in Korea PulseNet DB. According to WGS, the ciprofloxacin-resistant strains belong to the global dominant multidrug-resistant (MDR) haplotype H58 (SNP glpA C1047T, SptP protein Q185* (premature stop codon)) and do not harbor the MDR plasmid. H58-associated SNPs in membrane and metabolism genes, including yhdA, yajI, hyaE, tryE, rlpB and metH, are present. Additionally, phylogenetic analysis assigned the H58 strains to sublineage II, whereas the non-H58 strains are closely related to haplotype H50. The presence of high-level ciprofloxacin-resistant S. Typhi haplotype H58 in Korea was first confirmed as due to influx from overseas via travelers. This study provides information about intercontinental drug-resistant transmission between countries and suggests that travelers need to be careful about personal hygiene. Typhoid fever is a systemic human disease that involves gastroenteritis, fever, and severe diarrhea caused by Salmonella enterica serotype Typhi (S. Typhi) and requires prompt antibiotic treatment. Due to improved living standards, it has become a rare disease but is still prevalent in developing countries such as India and Southeast Asia. Most reported cases are related to travelers or immigrants from these regions. Because of treatment failure, serious morbidity, and economic loss, there is a global health issue with the emergence of antimicrobial-resistant strains associated with fluoroquinolones and third-generation cephalosporins. Of antimicrobial-resistant S. Typhi, haplotype H58 is a dominant multidrug-resistant lineage that has been reported in endemic regions over the past two decades. We identified fluoroquinolone resistance in cases of S. Typhi infection after travel to India. Among them, some strains highly resistant to ciprofloxacin were confirmed to have characteristics of haplotype H58. In Korea, S. Typhi haplotype H58 from travelers has not been confirmed before. This study provides information about intercontinental drug-resistant transmission between countries and suggests that travelers need to be careful about personal hygiene.
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Affiliation(s)
- Eunkyung Shin
- Division of Bacterial Diseases, Korea Centers for Diseases Control and Prevention, Cheongju, Republic of Korea
- College of Veterinary Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Jungsun Park
- Division of Bacterial Diseases, Korea Centers for Diseases Control and Prevention, Cheongju, Republic of Korea
| | - Hyun Ju Jeong
- Division of Bacterial Diseases, Korea Centers for Diseases Control and Prevention, Cheongju, Republic of Korea
| | - Ae Kyung Park
- Division of Bacterial Diseases, Korea Centers for Diseases Control and Prevention, Cheongju, Republic of Korea
| | - Kyoungin Na
- Division of Infectious Diseases Control, Korea Centers for Diseases Control and Prevention, Cheongju, Republic of Korea
| | - Hyerim Lee
- Division of Infectious Diseases Control, Korea Centers for Diseases Control and Prevention, Cheongju, Republic of Korea
| | - Jeong-hoon Chun
- Division of Bacterial Diseases, Korea Centers for Diseases Control and Prevention, Cheongju, Republic of Korea
| | - Kyu Jam Hwang
- Division of Bacterial Diseases, Korea Centers for Diseases Control and Prevention, Cheongju, Republic of Korea
| | - Chul-Joong Kim
- College of Veterinary Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Junyoung Kim
- Division of Bacterial Diseases, Korea Centers for Diseases Control and Prevention, Cheongju, Republic of Korea
- * E-mail:
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15
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Hotinger JA, Pendergrass HA, May AE. Molecular Targets and Strategies for Inhibition of the Bacterial Type III Secretion System (T3SS); Inhibitors Directly Binding to T3SS Components. Biomolecules 2021; 11:biom11020316. [PMID: 33669653 PMCID: PMC7922566 DOI: 10.3390/biom11020316] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/16/2021] [Accepted: 02/17/2021] [Indexed: 01/01/2023] Open
Abstract
The type III secretion system (T3SS) is a virulence apparatus used by many Gram-negative pathogenic bacteria to cause infections. Pathogens utilizing a T3SS are responsible for millions of infections yearly. Since many T3SS knockout strains are incapable of causing systemic infection, the T3SS has emerged as an attractive anti-virulence target for therapeutic design. The T3SS is a multiprotein molecular syringe that enables pathogens to inject effector proteins into host cells. These effectors modify host cell mechanisms in a variety of ways beneficial to the pathogen. Due to the T3SS’s complex nature, there are numerous ways in which it can be targeted. This review will be focused on the direct targeting of components of the T3SS, including the needle, translocon, basal body, sorting platform, and effector proteins. Inhibitors will be considered a direct inhibitor if they have a binding partner that is a T3SS component, regardless of the inhibitory effect being structural or functional.
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16
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Mylona E, Sanchez-Garrido J, Hoang Thu TN, Dongol S, Karkey A, Baker S, Shenoy AR, Frankel G. Very long O-antigen chains of Salmonella Paratyphi A inhibit inflammasome activation and pyroptotic cell death. Cell Microbiol 2021; 23:e13306. [PMID: 33355403 PMCID: PMC8609438 DOI: 10.1111/cmi.13306] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 12/02/2020] [Accepted: 12/18/2020] [Indexed: 11/28/2022]
Abstract
Salmonella Paratyphi A (SPtA) remains one of the leading causes of enteric (typhoid) fever. Yet, despite the recent increased rate of isolation from patients in Asia, our understanding of its pathogenesis is incomplete. Here we investigated inflammasome activation in human macrophages infected with SPtA. We found that SPtA induces GSDMD‐mediated pyroptosis via activation of caspase‐1, caspase‐4 and caspase‐8. Although we observed no cell death in the absence of a functional Salmonella pathogenicity island‐1 (SPI‐1) injectisome, HilA‐mediated overexpression of the SPI‐1 regulon enhances pyroptosis. SPtA expresses FepE, an LPS O‐antigen length regulator, which induces the production of very long O‐antigen chains. Using a ΔfepE mutant we established that the very long O‐antigen chains interfere with bacterial interactions with epithelial cells and impair inflammasome‐mediated macrophage cell death. Salmonella Typhimurium (STm) serovar has a lower FepE expression than SPtA, and triggers higher pyroptosis, conversely, increasing FepE expression in STm reduced pyroptosis. These results suggest that differential expression of FepE results in serovar‐specific inflammasome modulation, which mirrors the pro‐ and anti‐inflammatory strategies employed by STm and SPtA, respectively. Our studies point towards distinct mechanisms of virulence of SPtA, whereby it attenuates inflammasome‐mediated detection through the elaboration of very long LPS O‐polysaccharides.
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Affiliation(s)
- Elli Mylona
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK.,Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Department of Medicine, University of Cambridge, Cambridge, UK
| | - Julia Sanchez-Garrido
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Trang Nguyen Hoang Thu
- Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Sabina Dongol
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Abhilasha Karkey
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Stephen Baker
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Department of Medicine, University of Cambridge, Cambridge, UK
| | - Avinash R Shenoy
- Department of Infectious Disease, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Gad Frankel
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
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17
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Pan P, Zou F, He C, He Q, Yin J. Characterization and protective efficacy of a sptP mutant of Salmonella Paratyphi A. IMMUNITY INFLAMMATION AND DISEASE 2020; 8:774-781. [PMID: 33135379 PMCID: PMC7654428 DOI: 10.1002/iid3.369] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 10/15/2020] [Accepted: 10/21/2020] [Indexed: 01/24/2023]
Abstract
Background Salmonella Paratyphi A causes paratyphoid A, a severe systemic disease of people and remains a major public health problem in many parts of the world. In the interest of researching the roles of sptP on Salmonella Paratyphi A and developing a live‐attenuated vaccine candidate, an sptP mutant of Salmonella Paratyphi A SPA017 (SPA017ΔsptP) was constructed, and then its characterization, immunogenicity, and protective ability were evaluated. Results The deletion of sptP had no effect on growth and biochemical properties. Adhesion and invasion assays showed that the lack of sptP did not affect the adhesion of Salmonella Paratyphi A, but the invasive ability of the mutant strain was significantly decreased, the half‐lethal dose (LD50) of the mutant strain was 1.43 × 104 times of the parent strain in intraperitoneally injected mice. Single intraperitoneal vaccination with SPA017ΔsptP (1 × 105 CFU) in mice did not affect the body weight or elicit clinical symptoms relative to the control group, SPA017ΔsptP bacteria were isolated from livers and spleens of vaccinated mice at 14 days postvaccination. Notably, specific humoral and cellular immune responses were significantly induced. The protective assessment showed that the mutant strain could provide high‐level protection against subsequent challenge with the wild‐type SPA017 strain. Conclusions These results demonstrated that SptP plays an essential role in the pathogenicity of Salmonella Paratyphi A, and Salmonella Paratyphi A lacking sptP is immunogenic and protective in mice.
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Affiliation(s)
- Pengtao Pan
- Medical College, Xinxiang University, Xinxiang, China
| | - Fanyu Zou
- Medical College, Xinxiang University, Xinxiang, China
| | - Chuanshan He
- Second Hospital, Shanxi Medical University, Taiyuan, China
| | - Qunli He
- Medical College, Zhengzhou University of Industrial Technology, Zhengzhou, China
| | - Junlei Yin
- Medical College, Xinxiang University, Xinxiang, China
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18
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Wang M, Qazi IH, Wang L, Zhou G, Han H. Salmonella Virulence and Immune Escape. Microorganisms 2020; 8:microorganisms8030407. [PMID: 32183199 PMCID: PMC7143636 DOI: 10.3390/microorganisms8030407] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/02/2020] [Accepted: 03/10/2020] [Indexed: 02/07/2023] Open
Abstract
Salmonella genus represents the most common foodborne pathogens causing morbidity, mortality, and burden of disease in all regions of the world. The introduction of antimicrobial agents and Salmonella-specific phages has been considered as an effective intervention strategy to reduce Salmonella contamination. However, data from the United States, European countries, and low- and middle-income countries indicate that Salmonella cases are still a commonly encountered cause of bacterial foodborne diseases globally. The control programs have not been successful and even led to the emergence of some multidrug-resistant Salmonella strains. It is known that the host immune system is able to effectively prevent microbial invasion and eliminate microorganisms. However, Salmonella has evolved mechanisms of resisting host physical barriers and inhibiting subsequent activation of immune response through their virulence factors. There has been a high interest in understanding how Salmonella interacts with the host. Therefore, in the present review, we characterize the functions of Salmonella virulence genes and particularly focus on the mechanisms of immune escape in light of evidence from the emerging mainstream literature.
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Affiliation(s)
- Mengyao Wang
- Beijing Key Laboratory for Animal Genetic Improvement, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (M.W.); (L.W.)
- Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Izhar Hyder Qazi
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China;
- Department of Veterinary Anatomy and Histology, Shaheed Benazir Bhutto University of Veterinary and Animal Sciences, Sakrand 67210, Pakistan
| | - Linli Wang
- Beijing Key Laboratory for Animal Genetic Improvement, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (M.W.); (L.W.)
- Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Guangbin Zhou
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China;
- Correspondence: (H.H.); (G.Z.)
| | - Hongbing Han
- Beijing Key Laboratory for Animal Genetic Improvement, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (M.W.); (L.W.)
- Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
- Correspondence: (H.H.); (G.Z.)
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19
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Azimi T, Zamirnasta M, Sani MA, Soltan Dallal MM, Nasser A. Molecular Mechanisms of Salmonella Effector Proteins: A Comprehensive Review. Infect Drug Resist 2020; 13:11-26. [PMID: 32021316 PMCID: PMC6954085 DOI: 10.2147/idr.s230604] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 12/20/2019] [Indexed: 12/27/2022] Open
Abstract
Salmonella can be categorized into many serotypes, which are specific to known hosts or broadhosts. It makes no difference which one of the serotypes would penetrate the gastrointestinal tract because they all face similar obstacles such as mucus and microbiome. However, following their penetration, some species remain in the gastrointestinal tract; yet, others spread to another organ like gallbladder. Salmonella is required to alter the immune response to sustain its intracellular life. Changing the host response requires particular effector proteins and vehicles to translocate them. To this end, a categorized gene called Salmonella pathogenicity island (SPI) was developed; genes like Salmonella pathogenicity island encode aggressive or modulating proteins. Initially, Salmonella needs to be attached and stabilized via adhesin factor, without which no further steps can be taken. In this review, an attempt has been made to elaborate on each factor attached to the host cell or to modulating and aggressive proteins that evade immune systems. This review includes four sections: (A) attachment factors or T3SS- independent entrance, (B) effector proteins or T3SS-dependent entrance, (c) regulation of invasive genes, and (D) regulation of immune responses.
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Affiliation(s)
- Taher Azimi
- Pediatric Infections Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Students Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Zamirnasta
- Clinical Microbiology Research Center, Ilam University of Medical Science, Ilam, Iran
| | - Mahmood Alizadeh Sani
- Food Safety and Hygiene Division, Environmental health Department, School of Public Health, Tehran University of medical sciences, Tehran, Iran
- Students Research Committee, Department of Food Sciences and Technology, Faculty of Nutrition and Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Ahmad Nasser
- Clinical Microbiology Research Center, Ilam University of Medical Science, Ilam, Iran
- Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
- Department of Medical Microbiology, School of Medicine, Ilam University of Medical Science, Ilam, Iran
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20
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Lou L, Zhang P, Piao R, Wang Y. Salmonella Pathogenicity Island 1 (SPI-1) and Its Complex Regulatory Network. Front Cell Infect Microbiol 2019; 9:270. [PMID: 31428589 PMCID: PMC6689963 DOI: 10.3389/fcimb.2019.00270] [Citation(s) in RCA: 163] [Impact Index Per Article: 32.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 07/12/2019] [Indexed: 11/30/2022] Open
Abstract
Salmonella species can infect a diverse range of birds, reptiles, and mammals, including humans. The type III protein secretion system (T3SS) encoded by Salmonella pathogenicity island 1 (SPI-1) delivers effector proteins required for intestinal invasion and the production of enteritis. The T3SS is regarded as the most important virulence factor of Salmonella. SPI-1 encodes transcription factors that regulate the expression of some virulence factors of Salmonella, while other transcription factors encoded outside SPI-1 participate in the expression of SPI-1-encoded genes. SPI-1 genes are responsible for the invasion of host cells, regulation of the host immune response, e.g., the host inflammatory response, immune cell recruitment and apoptosis, and biofilm formation. The regulatory network of SPI-1 is very complex and crucial. Here, we review the function, effectors, and regulation of SPI-1 genes and their contribution to the pathogenicity of Salmonella.
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Affiliation(s)
- Lixin Lou
- Department of Infectious Diseases, First Hospital of Jilin University, Changchun, China
| | - Peng Zhang
- Department of Infectious Diseases, First Hospital of Jilin University, Changchun, China.,Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Rongli Piao
- Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Department of Gastroenterology, First Hospital of Jilin University, Changchun, China
| | - Yang Wang
- Department of Infectious Diseases, First Hospital of Jilin University, Changchun, China.,Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
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21
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McDowell MA, Byrne AM, Mylona E, Johnson R, Sagfors A, Crepin VF, Lea S, Frankel G. The S. Typhi effector StoD is an E3/E4 ubiquitin ligase which binds K48- and K63-linked diubiquitin. Life Sci Alliance 2019; 2:2/3/e201800272. [PMID: 31142637 PMCID: PMC6545606 DOI: 10.26508/lsa.201800272] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 05/03/2019] [Accepted: 05/07/2019] [Indexed: 11/24/2022] Open
Abstract
Salmonella Typhi is estimated to cause 100,000–200,000 deaths annually, yet its infection strategy remains elusive. This article reports of the first Typhi-specific effector, which has an E3/E4 ubiquitin ligase activity and can uniquely bind K48- and K63-linked diubiquitin. Salmonella enterica (e.g., serovars Typhi and Typhimurium) relies on translocation of effectors via type III secretion systems (T3SS). Specialization of typhoidal serovars is thought to be mediated via pseudogenesis. Here, we show that the Salmonella Typhi STY1076/t1865 protein, named StoD, a homologue of the enteropathogenic Escherichia coli/enterohemorrhagic E. coli/Citrobacter rodentium NleG, is a T3SS effector. The StoD C terminus (StoD-C) is a U-box E3 ubiquitin ligase, capable of autoubiquitination in the presence of multiple E2s. The crystal structure of the StoD N terminus (StoD-N) at 2.5 Å resolution revealed a ubiquitin-like fold. In HeLa cells expressing StoD, ubiquitin is redistributed into puncta that colocalize with StoD. Binding assays showed that StoD-N and StoD-C bind the same exposed surface of the β-sheet of ubiquitin, suggesting that StoD could simultaneously interact with two ubiquitin molecules. Consistently, StoD interacted with both K63- (KD = 5.6 ± 1 μM) and K48-linked diubiquitin (KD = 15 ± 4 μM). Accordingly, we report the first S. Typhi–specific T3SS effector. We suggest that StoD recognizes and ubiquitinates pre-ubiquitinated targets, thus subverting intracellular signaling by functioning as an E4 enzyme.
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Affiliation(s)
| | - Alexander Mp Byrne
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, UK
| | - Elli Mylona
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, UK
| | - Rebecca Johnson
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, UK
| | - Agnes Sagfors
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, UK
| | - Valerie F Crepin
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, UK
| | - Susan Lea
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Gad Frankel
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, UK
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22
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Rakov AV, Mastriani E, Liu SL, Schifferli DM. Association of Salmonella virulence factor alleles with intestinal and invasive serovars. BMC Genomics 2019; 20:429. [PMID: 31138114 PMCID: PMC6540521 DOI: 10.1186/s12864-019-5809-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 05/20/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The role of Salmonella virulence factor (VF) allelic variation in modulating pathogenesis or host specificity has only been demonstrated in a few cases, mostly through serendipitous findings. Virulence factor (VF) alleles from Salmonella enterica subsp. enterica genomes were compared to identify potential associations with the host-adapted invasive serovars Typhi, Dublin, Choleraesuis, and Gallinarum, and with the broad host-range intestinal serovars Typhimurium, Enteritidis, and Newport. RESULTS Through a bioinformatics analysis of 500 Salmonella genomes, we have identified allelic variants of 70 VFs, many of which are associated with either one of the four host-adapted invasive Salmonella serovars or one of the three broad host-range intestinal serovars. In addition, associations between specific VF alleles and intra-serovar clusters, sequence types (STs) and/or host-adapted FimH adhesins were identified. Moreover, new allelic VF associations with non-typhoidal S. Enteritidis and S. Typhimurium (NTS) or invasive NTS (iNTS) were detected. CONCLUSIONS By analogy to the previously shown association of specific FimH adhesin alleles with optimal binding by host adapted Salmonella serovars, lineages or strains, we predict that some of the identified association of other VF alleles with host-adapted serovars, lineages or strains will reflect specific contributions to host adaptation and/or pathogenesis. The identification of these allelic associations will support investigations of the biological impact of VF alleles and better characterize the role of allelic variation in Salmonella pathogenesis. Most relevant functional experiments will test the potential causal contribution of the detected FimH-associated VF variants in host adapted virulence.
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Affiliation(s)
- Alexey V. Rakov
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania USA
- Present Address: Somov Institute of Epidemiology and Microbiology, Vladivostok, Russia
| | - Emilio Mastriani
- Systemomics Center, College of Pharmacy, Genomics Research Center, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Harbin Medical University, Harbin, China
- HMU-UCCSM Centre for Infection and Genomics, Harbin Medical University, Harbin, China
| | - Shu-Lin Liu
- Systemomics Center, College of Pharmacy, Genomics Research Center, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Harbin Medical University, Harbin, China
- HMU-UCCSM Centre for Infection and Genomics, Harbin Medical University, Harbin, China
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Canada
| | - Dieter M. Schifferli
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania USA
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23
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Dhroso A, Eidson S, Korkin D. Genome-wide prediction of bacterial effector candidates across six secretion system types using a feature-based statistical framework. Sci Rep 2018; 8:17209. [PMID: 30464223 PMCID: PMC6249201 DOI: 10.1038/s41598-018-33874-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 10/06/2018] [Indexed: 01/12/2023] Open
Abstract
Gram-negative bacteria are responsible for hundreds of millions infections worldwide, including the emerging hospital-acquired infections and neglected tropical diseases in the third-world countries. Finding a fast and cheap way to understand the molecular mechanisms behind the bacterial infections is critical for efficient diagnostics and treatment. An important step towards understanding these mechanisms is the discovery of bacterial effectors, the proteins secreted into the host through one of the six common secretion system types. Unfortunately, current prediction methods are designed to specifically target one of three secretion systems, and no accurate "secretion system-agnostic" method is available. Here, we present PREFFECTOR, a computational feature-based approach to discover effector candidates in Gram-negative bacteria, without prior knowledge on bacterial secretion system(s) or cryptic secretion signals. Our approach was first evaluated using several assessment protocols on a manually curated, balanced dataset of experimentally determined effectors across all six secretion systems, as well as non-effector proteins. The evaluation revealed high accuracy of the top performing classifiers in PREFFECTOR, with the small false positive discovery rate across all six secretion systems. Our method was also applied to six bacteria that had limited knowledge on virulence factors or secreted effectors. PREFFECTOR web-server is freely available at: http://korkinlab.org/preffector .
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Affiliation(s)
- Andi Dhroso
- Department of Computer Science, and Bioinformatics and Computational Biology Program, Worcester Polytechnic Institute, Worcester, MA, USA
| | - Samantha Eidson
- Mathematics and Computer Science Department, Fontbonne University, St. Louis, MO, USA
| | - Dmitry Korkin
- Department of Computer Science, and Bioinformatics and Computational Biology Program, Worcester Polytechnic Institute, Worcester, MA, USA.
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BoseDasgupta S, Pieters J. Macrophage-microbe interaction: lessons learned from the pathogen Mycobacterium tuberculosis. Semin Immunopathol 2018; 40:577-591. [PMID: 30306257 DOI: 10.1007/s00281-018-0710-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 09/17/2018] [Indexed: 02/07/2023]
Abstract
Macrophages, being the cornerstone of the immune system, have adapted the ancient nutrient acquisition mechanism of phagocytosis to engulf various infectious organisms thereby helping to orchestrate an appropriate host response. Phagocytosis refers to the process of internalization and degradation of particulate material, damaged and senescent cells and microorganisms by specialized cells, after which the vesicle containing the ingested particle, the phagosome, matures into acidic phagolysosomes upon fusion with hydrolytic enzyme-containing lysosomes. The destructive power of the macrophage is further exacerbated through the induction of macrophage activation upon a variety of inflammatory stimuli. Despite being the end-point for many phagocytosed microbes, the macrophage can also serve as an intracellular survival niche for a number of intracellular microorganisms. One microbe that is particularly successful at surviving within macrophages is the pathogen Mycobacterium tuberculosis, which can efficiently manipulate the macrophage at several levels, including modulation of the phagocytic pathway as well as interfering with a number of immune activation pathways that normally would lead to eradication of the internalized bacilli. M. tuberculosis excels at circumventing destruction within macrophages, thus establishing itself successfully for prolonged times within the macrophage. In this contribution, we describe a number of general features of macrophages in the context of their function to clear an infection, and highlight the strategies employed by M. tuberculosis to counter macrophage attack. Interestingly, research on the evasion tactics employed by M. tuberculosis within macrophages not only helps to design strategies to curb tuberculosis, but also allows a better understanding of host cell biology.
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Affiliation(s)
- Somdeb BoseDasgupta
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, 721302, India.
| | - Jean Pieters
- Department of Biochemistry, Biozentrum, University of Basel, 50-70 Klingelbergstrasse, 4056, Basel, Switzerland.
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Johnson R, Mylona E, Frankel G. TyphoidalSalmonella: Distinctive virulence factors and pathogenesis. Cell Microbiol 2018; 20:e12939. [DOI: 10.1111/cmi.12939] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/06/2018] [Accepted: 07/13/2018] [Indexed: 01/13/2023]
Affiliation(s)
- Rebecca Johnson
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences; Imperial College London; London UK
| | - Elli Mylona
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences; Imperial College London; London UK
| | - Gad Frankel
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences; Imperial College London; London UK
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Why Is Eradicating Typhoid Fever So Challenging: Implications for Vaccine and Therapeutic Design. Vaccines (Basel) 2018; 6:vaccines6030045. [PMID: 30042307 PMCID: PMC6160957 DOI: 10.3390/vaccines6030045] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 07/19/2018] [Accepted: 07/23/2018] [Indexed: 01/22/2023] Open
Abstract
Salmonella enterica serovar Typhi (S. Typhi) and S. Paratyphi, namely typhoidal Salmonellae, are the cause of (para) typhoid fever, which is a devastating systemic infectious disease in humans. In addition, the spread of multidrug-resistant (MDR) and extensively drug-resistant (XDR) S. Typhi in many low and middle-income countries poses a significant risk to human health. While currently available typhoid vaccines and therapeutics are efficacious, they have some limitations. One important limitation is the lack of controlling individuals who chronically carry S. Typhi. However, due to the strict host specificity of S. Typhi to humans, S. Typhi research is hampered. As a result, our understanding of S. Typhi pathogenesis is incomplete, thereby delaying the development and improvement of prevention and treatment strategies. Nonetheless, to better combat and contain S. Typhi, it is vital to develop a vaccine and therapy for controlling both acutely and chronically infected individuals. This review discusses how scientists are trying to combat typhoid fever, why it is so challenging to do so, which approaches show promise, and what we know about the pathogenesis of S. Typhi chronic infection.
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Nickerson KP, Senger S, Zhang Y, Lima R, Patel S, Ingano L, Flavahan WA, Kumar DKV, Fraser CM, Faherty CS, Sztein MB, Fiorentino M, Fasano A. Salmonella Typhi Colonization Provokes Extensive Transcriptional Changes Aimed at Evading Host Mucosal Immune Defense During Early Infection of Human Intestinal Tissue. EBioMedicine 2018; 31:92-109. [PMID: 29735417 PMCID: PMC6013756 DOI: 10.1016/j.ebiom.2018.04.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 04/02/2018] [Accepted: 04/05/2018] [Indexed: 12/29/2022] Open
Abstract
Commensal microorganisms influence a variety of host functions in the gut, including immune response, glucose homeostasis, metabolic pathways and oxidative stress, among others. This study describes how Salmonella Typhi, the pathogen responsible for typhoid fever, uses similar strategies to escape immune defense responses and survive within its human host. To elucidate the early mechanisms of typhoid fever, we performed studies using healthy human intestinal tissue samples and "mini-guts," organoids grown from intestinal tissue taken from biopsy specimens. We analyzed gene expression changes in human intestinal specimens and bacterial cells both separately and after colonization. Our results showed mechanistic strategies that S. Typhi uses to rearrange the cellular machinery of the host cytoskeleton to successfully invade the intestinal epithelium, promote polarized cytokine release and evade immune system activation by downregulating genes involved in antigen sampling and presentation during infection. This work adds novel information regarding S. Typhi infection pathogenesis in humans, by replicating work shown in traditional cell models, and providing new data that can be applied to future vaccine development strategies.
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Affiliation(s)
- K P Nickerson
- Department of Pediatric Gastroenterology, Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Boston, MA, United States; Department of Pediatrics, Harvard Medical School, Harvard University, Boston, MA, United States.
| | - S Senger
- Department of Pediatric Gastroenterology, Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Boston, MA, United States; Department of Pediatrics, Harvard Medical School, Harvard University, Boston, MA, United States
| | - Y Zhang
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, United States
| | - R Lima
- Department of Pediatric Gastroenterology, Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Boston, MA, United States
| | - S Patel
- Department of Pediatric Gastroenterology, Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Boston, MA, United States
| | - L Ingano
- Department of Pediatric Gastroenterology, Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Boston, MA, United States
| | - W A Flavahan
- Department of Pathology, Massachusetts General Hospital, Boston, MA, United States
| | - D K V Kumar
- Department for the Neuroscience of Genetics and Aging, Massachusetts General Hospital, Boston, MA, United States
| | - C M Fraser
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, United States
| | - C S Faherty
- Department of Pediatric Gastroenterology, Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Boston, MA, United States; Department of Pediatrics, Harvard Medical School, Harvard University, Boston, MA, United States
| | - M B Sztein
- Center for Vaccine Development, Department of Pediatrics, University of Maryland, Baltimore, MD, United States
| | - M Fiorentino
- Department of Pediatric Gastroenterology, Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Boston, MA, United States; Department of Pediatrics, Harvard Medical School, Harvard University, Boston, MA, United States
| | - A Fasano
- Department of Pediatric Gastroenterology, Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Boston, MA, United States; Department of Pediatrics, Harvard Medical School, Harvard University, Boston, MA, United States.
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Abstract
Background Like many members of the Enterobacteriaceae family, Yersinia ruckeri has the ability to invade non professional phagocytic cells. Intracellular location is advantageous for the bacterium because it shields it from the immune system and can help it cross epithelial membranes and gain entry into the host. In the present manuscript, we report on our investigation regarding the mechanisms of Y. ruckeri’s invasion of host cells. Results A gentamycin assay was applied to two isolates, belonging to both the biotype 1 (ATCC 29473) and biotype 2 (A7959–11) and using several cell culture types: Atlantic Salmon Kidney, Salmon Head Kidney and, Chinook salmon embryos cells at both low and high passage numbers. Varying degrees of sensitivity to Y. ruckeri infection were found between the cell types and the biotype 1 strain was found to be more invasive than the non-motile biotype 2 isolate. Furthermore, the effect of six chemical compounds (Cytochalasin D, TAE 226, vinblastine, genistein, colchicine and, N-acetylcysteine), known to interfere with bacterial invasion strategies, were investigated. All of these compounds had a significant impact on the ability of the bacterium to invade host cells. Changes in the concentration of bacterial cells over time were investigated and the results suggested that neither isolate could survive intracellularly for sustained periods. Conclusions These results suggest that Y. ruckeri can gain entrance into host cells through several mechanisms, and might take advantage of both the actin and microtubule cytoskeletal systems.
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Comparison of Salmonella enterica Serovars Typhi and Typhimurium Reveals Typhoidal Serovar-Specific Responses to Bile. Infect Immun 2018; 86:IAI.00490-17. [PMID: 29229736 PMCID: PMC5820949 DOI: 10.1128/iai.00490-17] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 12/06/2017] [Indexed: 01/19/2023] Open
Abstract
Salmonella enterica serovars Typhi and Typhimurium cause typhoid fever and gastroenteritis, respectively. A unique feature of typhoid infection is asymptomatic carriage within the gallbladder, which is linked with S. Typhi transmission. Despite this, S. Typhi responses to bile have been poorly studied. Transcriptome sequencing (RNA-Seq) of S. Typhi Ty2 and a clinical S. Typhi isolate belonging to the globally dominant H58 lineage (strain 129-0238), as well as S. Typhimurium 14028, revealed that 249, 389, and 453 genes, respectively, were differentially expressed in the presence of 3% bile compared to control cultures lacking bile. fad genes, the actP-acs operon, and putative sialic acid uptake and metabolism genes (t1787 to t1790) were upregulated in all strains following bile exposure, which may represent adaptation to the small intestine environment. Genes within the Salmonella pathogenicity island 1 (SPI-1), those encoding a type IIII secretion system (T3SS), and motility genes were significantly upregulated in both S. Typhi strains in bile but downregulated in S. Typhimurium. Western blots of the SPI-1 proteins SipC, SipD, SopB, and SopE validated the gene expression data. Consistent with this, bile significantly increased S. Typhi HeLa cell invasion, while S. Typhimurium invasion was significantly repressed. Protein stability assays demonstrated that in S. Typhi the half-life of HilD, the dominant regulator of SPI-1, is three times longer in the presence of bile; this increase in stability was independent of the acetyltransferase Pat. Overall, we found that S. Typhi exhibits a specific response to bile, especially with regard to virulence gene expression, which could impact pathogenesis and transmission.
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Duncan SA, Baganizi DR, Sahu R, Singh SR, Dennis VA. SOCS Proteins as Regulators of Inflammatory Responses Induced by Bacterial Infections: A Review. Front Microbiol 2017; 8:2431. [PMID: 29312162 PMCID: PMC5733031 DOI: 10.3389/fmicb.2017.02431] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Accepted: 11/23/2017] [Indexed: 12/31/2022] Open
Abstract
Severe bacterial infections can lead to both acute and chronic inflammatory conditions. Innate immunity is the first defense mechanism employed against invading bacterial pathogens through the recognition of conserved molecular patterns on bacteria by pattern recognition receptors (PRRs), especially the toll-like receptors (TLRs). TLRs recognize distinct pathogen-associated molecular patterns (PAMPs) that play a critical role in innate immune responses by inducing the expression of several inflammatory genes. Thus, activation of immune cells is regulated by cytokines that use the Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling pathway and microbial recognition by TLRs. This system is tightly controlled by various endogenous molecules to allow for an appropriately regulated and safe host immune response to infections. Suppressor of cytokine signaling (SOCS) family of proteins is one of the central regulators of microbial pathogen-induced signaling of cytokines, principally through the inhibition of the activation of JAK/STAT signaling cascades. This review provides recent knowledge regarding the role of SOCS proteins during bacterial infections, with an emphasis on the mechanisms involved in their induction and regulation of antibacterial immune responses. Furthermore, the implication of SOCS proteins in diverse processes of bacteria to escape host defenses and in the outcome of bacterial infections are discussed, as well as the possibilities offered by these proteins for future targeted antimicrobial therapies.
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Affiliation(s)
- Skyla A Duncan
- Center for NanoBiotechnology Research, Alabama State University, Montgomery, AL, United States
| | - Dieudonné R Baganizi
- Center for NanoBiotechnology Research, Alabama State University, Montgomery, AL, United States
| | - Rajnish Sahu
- Center for NanoBiotechnology Research, Alabama State University, Montgomery, AL, United States
| | - Shree R Singh
- Center for NanoBiotechnology Research, Alabama State University, Montgomery, AL, United States
| | - Vida A Dennis
- Center for NanoBiotechnology Research, Alabama State University, Montgomery, AL, United States
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