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Kang L, You J, Li Y, Huang R, Wu S. Effects and mechanisms of Salmonella plasmid virulence gene spv on host-regulated cell death. Curr Microbiol 2024; 81:86. [PMID: 38305917 DOI: 10.1007/s00284-024-03612-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 01/04/2024] [Indexed: 02/03/2024]
Abstract
Salmonella is responsible for the majority of food poisoning outbreaks around the world. Pathogenic Salmonella mostly carries a virulence plasmid that contains the Salmonella plasmid virulence gene (spv), a highly conserved sequence encoding effector proteins that can manipulate host cells. Intestinal epithelial cells are crucial components of the innate immune system, acting as the first barrier of defense against infection. When the barrier is breached, Salmonella encounters the underlying macrophages in lamina propria, triggering inflammation and engaging in combat with immune cells recruited by inflammatory factors. Host regulated cell death (RCD) provides a variety of means to fight against or favour Salmonella infection. However, Salmonella releases effector proteins to regulate RCD, evading host immune killing and neutralizing host antimicrobial effects. This review provides an overview of pathogen-host interactions in terms of (1) pathogenicity of Salmonella spv on intestinal epithelial cells and macrophages, (2) mechanisms of host RCD to limit or promote pathogenic Salmonella expansion, and (3) effects and mechanisms of Salmonella spv gene on host RCD.
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Affiliation(s)
- Li Kang
- Department of Medical Microbiology, School of Biology & Basic Medical Science, Suzhou Medical College of Soochow University, Suzhou, 215123, Jiangsu Province, China
- 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, 215123, Jiangsu Province, China
| | - Jiayi You
- Department of Medical Microbiology, School of Biology & Basic Medical Science, Suzhou Medical College of Soochow University, Suzhou, 215123, Jiangsu Province, China
- 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, 215123, Jiangsu Province, China
| | - Yuanyuan Li
- Experimental Center, Suzhou Medical College of Soochow University, Suzhou, 215123, Jiangsu Province, China
- 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, 215123, Jiangsu Province, China
| | - Rui Huang
- Department of Medical Microbiology, School of Biology & Basic Medical Science, Suzhou Medical College of Soochow University, Suzhou, 215123, Jiangsu Province, China
- 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, 215123, Jiangsu Province, China
| | - Shuyan Wu
- Department of Medical Microbiology, School of Biology & Basic Medical Science, Suzhou Medical College of Soochow University, Suzhou, 215123, Jiangsu Province, China.
- 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, 215123, Jiangsu Province, China.
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2
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Li W, Ren Q, Ni T, Zhao Y, Sang Z, Luo R, Li Z, Li S. Strategies adopted by Salmonella to survive in host: a review. Arch Microbiol 2023; 205:362. [PMID: 37904066 DOI: 10.1007/s00203-023-03702-w] [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: 09/01/2023] [Revised: 09/30/2023] [Accepted: 10/05/2023] [Indexed: 11/01/2023]
Abstract
Salmonella, a Gram-negative bacterium that infects humans and animals, causes diseases ranging from gastroenteritis to severe systemic infections. Here, we discuss various strategies used by Salmonella against host cell defenses. Epithelial cell invasion largely depends on a Salmonella pathogenicity island (SPI)-1-encoded type 3 secretion system, a molecular syringe for injecting effector proteins directly into host cells. The internalization of Salmonella into macrophages is primarily driven by phagocytosis. After entering the host cell cytoplasm, Salmonella releases many effectors to achieve intracellular survival and replication using several secretion systems, primarily an SPI-2-encoded type 3 secretion system. Salmonella-containing vacuoles protect Salmonella from contacting bactericidal substances in epithelial cells and macrophages. Salmonella modulates the immunity, metabolism, cell cycle, and viability of host cells to expand its survival in the host, and the intracellular environment of Salmonella-infected cells promotes its virulence. This review provides insights into how Salmonella subverts host cell defenses for survival.
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Affiliation(s)
- Wanwu Li
- College of Basic Medicine and Forensic Medicine, Henan University of Science and Technology, Luoyang, China
| | - Qili Ren
- College of Basic Medicine and Forensic Medicine, Henan University of Science and Technology, Luoyang, China
| | - Ting Ni
- College of Basic Medicine and Forensic Medicine, Henan University of Science and Technology, Luoyang, China
| | - Yifei Zhao
- College of Basic Medicine and Forensic Medicine, Henan University of Science and Technology, Luoyang, China
| | - Zichun Sang
- College of Basic Medicine and Forensic Medicine, Henan University of Science and Technology, Luoyang, China
| | - Renli Luo
- College of Basic Medicine and Forensic Medicine, Henan University of Science and Technology, Luoyang, China
| | - Zhongjie Li
- College of Basic Medicine and Forensic Medicine, Henan University of Science and Technology, Luoyang, China.
| | - Sanqiang Li
- College of Basic Medicine and Forensic Medicine, Henan University of Science and Technology, Luoyang, China.
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3
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Research Progress on Small Molecular Inhibitors of the Type 3 Secretion System. Molecules 2022; 27:molecules27238348. [PMID: 36500441 PMCID: PMC9740592 DOI: 10.3390/molecules27238348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/22/2022] [Accepted: 11/23/2022] [Indexed: 12/05/2022] Open
Abstract
The overuse of antibiotics has led to severe bacterial drug resistance. Blocking pathogen virulence devices is a highly effective approach to combating bacterial resistance worldwide. Type three secretion systems (T3SSs) are significant virulence factors in Gram-negative pathogens. Inhibition of these systems can effectively weaken infection whilst having no significant effect on bacterial growth. Therefore, T3SS inhibitors may be a powerful weapon against resistance in Gram-negative bacteria, and there has been increasing interest in the research and development of T3SS inhibitors. This review outlines several reported small-molecule inhibitors of the T3SS, covering those of synthetic and natural origin, including their sources, structures, and mechanisms of action.
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4
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Tahir H, Basit A, Tariq H, Haider Z, Ullah A, Hayat Z, Rehman SU. Coupling CRISPR/Cas9 and Lambda Red Recombineering System for Genome Editing of Salmonella Gallinarum and the Effect of ssaU Knock-Out Mutant on the Virulence of Bacteria. Biomedicines 2022; 10:biomedicines10123028. [PMID: 36551784 PMCID: PMC9776377 DOI: 10.3390/biomedicines10123028] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/13/2022] [Accepted: 11/15/2022] [Indexed: 11/25/2022] Open
Abstract
The poultry industry in developing countries still faces a significant threat from fowl typhoid, a disease caused by Salmonella Gallinarum that has been well contained in more economically developed countries. In addition to the virulence exhibited by large virulence plasmid (85 kb), Salmonella Pathogenicity Island 2 in S. Gallinarum plays a key role in mediating disease through its type III secretion systems (TTSS). The TTSS secrete effector protein across the Salmonella containing vacuoles and mediate the internalization of bacteria by modulating vesicular passage. In this study, candidate virulent ssaU gene (~1 kb) encoding type III secretion system was successfully deleted from indigenously isolated S. Gallinarum genome through homology-directed repair using CRISPR/Cas9 and lambda recombination systems. CRISPR/Cas9-based genome editing of poultry-derived Salmonella Gallinarum has not been previously reported, which might be linked to a lack of efficiency in its genetic tools. This is the first study which demonstrates a complete CRISPR/Cas9-based gene deletion from this bacterial genome. More importantly, a poultry experimental model was employed to assess the virulence potential of this mutant strain (ΔssaU_SG18) which was unable to produce any mortality in the experimentally challenged birds as compared to the wild type strain. No effect on weight gain was observed whereas bacteria were unable to colonize the intestine and liver in our challenge model. This in vivo loss of virulence in mutant strain provides an excellent functionality of this system to be useful in live vaccine development against this resistant and patho genic bacteria.
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Affiliation(s)
- Hamza Tahir
- Institute of Microbiology and Molecular Genetics, University of the Punjab, Lahore 54590, Pakistan
| | - Abdul Basit
- Institute of Microbiology and Molecular Genetics, University of the Punjab, Lahore 54590, Pakistan
- School of Biology, University of St Andrews, St Andrews KY16 9AJ, UK
| | - Hafsa Tariq
- Institute of Microbiology and Molecular Genetics, University of the Punjab, Lahore 54590, Pakistan
| | - Zulquernain Haider
- Institute of Microbiology and Molecular Genetics, University of the Punjab, Lahore 54590, Pakistan
| | - Asim Ullah
- Institute of Microbiology and Molecular Genetics, University of the Punjab, Lahore 54590, Pakistan
- Division of Infection and Immunity, The Roslin Institute, University of Edinbrugh, Edinburgh EH8 9YL, UK
| | - Zafar Hayat
- Department of Animal Nutrition, University of Veterinary and Animal Sciences, Lahore 54000, Pakistan
- Department of Animal Sciences, University of Sargodha, Sargodha 40100, Pakistan
| | - Shafiq Ur Rehman
- Division of Infection and Immunity, The Roslin Institute, University of Edinbrugh, Edinburgh EH8 9YL, UK
- Correspondence: ; Tel.: +92-3214905423
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5
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Ramatla TA, Mphuthi N, Ramaili T, Taioe M, Thekisoe O, Syakalima M. Molecular detection of zoonotic pathogens causing gastroenteritis in humans:
Salmonella
spp.,
Shigella
spp. and
Escherichia coli
isolated from
Rattus
species inhabiting chicken farms in North West Province, South Africa. J S Afr Vet Assoc 2022; 93:63-69. [DOI: 10.36303/jsava.83] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023] Open
Affiliation(s)
- TA Ramatla
- Unit for Environmental Sciences and Management, North-West University,
South Africa
- Department of Animal Health, Faculty of Natural and Agricultural Sciences, North-West University,
South Africa
| | - N Mphuthi
- Department of Animal Health, Faculty of Natural and Agricultural Sciences, North-West University,
South Africa
| | - T Ramaili
- Department of Animal Health, Faculty of Natural and Agricultural Sciences, North-West University,
South Africa
| | - M Taioe
- Unit for Environmental Sciences and Management, North-West University,
South Africa
- Epidemiology, Parasites and Vectors, Agriculture Research Council, Onderstepoort Veterinary Research,
South Africa
| | - O Thekisoe
- Unit for Environmental Sciences and Management, North-West University,
South Africa
| | - M Syakalima
- Department of Animal Health, Faculty of Natural and Agricultural Sciences, North-West University,
South Africa
- University of Zambia, School of Veterinary Medicine, Department of Disease Control,
Zambia
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6
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Fang Z, Méresse S. Endomembrane remodeling and dynamics in Salmonella infection. MICROBIAL CELL (GRAZ, AUSTRIA) 2022; 9:24-41. [PMID: 35127930 PMCID: PMC8796136 DOI: 10.15698/mic2022.02.769] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 12/08/2021] [Accepted: 12/10/2021] [Indexed: 11/13/2022]
Abstract
Salmonellae are bacteria that cause moderate to severe infections in humans, depending on the strain and the immune status of the infected host. These pathogens have the particularity of residing in the cells of the infected host. They are usually found in a vacuolar compartment that the bacteria shape with the help of effector proteins. Following invasion of a eukaryotic cell, the bacterial vacuole undergoes maturation characterized by changes in localization, composition and morphology. In particular, membrane tubules stretching over the microtubule cytoskeleton are formed from the bacterial vacuole. Although these tubules do not occur in all infected cells, they are functionally important and promote intracellular replication. This review focuses on the role and significance of membrane compartment remodeling observed in infected cells and the bacterial and host cell pathways involved.
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Affiliation(s)
- Ziyan Fang
- Aix Marseille University, CNRS, INSERM, CIML, Marseille, France
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7
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Deng Q, Yang S, Sun L, Dong K, Li Y, Wu S, Huang R. Salmonella effector SpvB aggravates dysregulation of systemic iron metabolism via modulating the hepcidin-ferroportin axis. Gut Microbes 2022; 13:1-18. [PMID: 33475464 PMCID: PMC7833757 DOI: 10.1080/19490976.2020.1849996] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Iron withholding, an essential component of nutritional immunity, plays a fundamental role in host resistance to Salmonella infection. Our previous study showed that SpvB, an important pSLT-encoded cytotoxic effector, facilitated Salmonella pathogenesis within macrophages via perturbing cellular iron metabolism. However, the underlying mechanisms of SpvB in Salmonella-relevant disorders of systemic iron metabolism have not yet been identified. Here, we demonstrated that SpvB facilitated Salmonella to scavenge iron from the host by modulating the hepcidin-ferroportin axis, a key regulator of systemic iron metabolism. We observed that SpvB enhanced hepatic hepcidin synthesis in a STAT3-dependent manner, but not the BMP/SMAD pathway. This subsequently resulted in a reduction of the unique cellular iron exporter ferroportin, which facilitated hypoferremia and hepatic iron accumulation and ultimately countered the limitation of iron availability, thereby improving the chances of Salmonella survival and replication. Moreover, SpvB promoted the production of proinflammatory molecules associated with the infiltration of inflammatory cells via highly upregulating TREM-1 signaling. Our data supported a role of TREM-1 in SpvB-related dysregulation of host iron metabolism and suggested that targeting TREM-1 might provide a potential therapeutic strategy to prevent or alleviate Salmonella pathogenesis.
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Affiliation(s)
- Qifeng Deng
- Department of Medical Microbiology, School of Biology & Basic Medical Sciences, Medical College of Soochow University, Suzhou, Jiangsu, PR China,CONTACT Shuyan Wu Department of Medical Microbiology, School of Biology & Basic Medical Sciences, Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, Jiangsu 215123, PR China
| | - Sidi Yang
- Department of Medical Microbiology, School of Biology & Basic Medical Sciences, Medical College of Soochow University, Suzhou, Jiangsu, PR China,Rui Huang Department of Medical Microbiology, School of Biology & Basic Medical Sciences, Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, Jiangsu 215123, PR China
| | - Lanqing Sun
- Department of Medical Microbiology, School of Biology & Basic Medical Sciences, Medical College of Soochow University, Suzhou, Jiangsu, PR China
| | - Kedi Dong
- Department of Medical Microbiology, School of Biology & Basic Medical Sciences, Medical College of Soochow University, Suzhou, Jiangsu, PR China
| | - Yuanyuan Li
- Department of Medical Microbiology, School of Biology & Basic Medical Sciences, Medical College of Soochow University, Suzhou, Jiangsu, PR China
| | - Shuyan Wu
- Department of Medical Microbiology, School of Biology & Basic Medical Sciences, Medical College of Soochow University, Suzhou, Jiangsu, PR China,CONTACT Shuyan Wu Department of Medical Microbiology, School of Biology & Basic Medical Sciences, Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, Jiangsu 215123, PR China
| | - Rui Huang
- Department of Medical Microbiology, School of Biology & Basic Medical Sciences, Medical College of Soochow University, Suzhou, Jiangsu, PR China,Rui Huang Department of Medical Microbiology, School of Biology & Basic Medical Sciences, Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, Jiangsu 215123, PR China
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8
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Abstract
Salmonella enterica invade the host via the intestinal tract. There are ~ 2 thousand distinct serovars of non-typhoidal Salmonella (NTS) that can cause gastroenteritis in normal hosts, but bacteremia is an uncommon complication of gastroenteritis except at the extremes of age [1]. In contrast, enteric fever and invasive NTS infections (iNTS) are each caused by only a few serovars of S. enterica (Table 1), and bacteremia not gastroenteritis is their principal manifestation.
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Affiliation(s)
- Joshua Fierer
- Department of Medicine, Division of Infectious Diseases, University of California, San Diego School of Medicine, La Jolla, California, USA
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9
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Herod A, Emond-Rheault JG, Tamber S, Goodridge L, Lévesque RC, Rohde J. Genomic and phenotypic analysis of SspH1 identifies a new Salmonella effector, SspH3. Mol Microbiol 2021; 117:770-789. [PMID: 34942035 DOI: 10.1111/mmi.14871] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 12/19/2021] [Accepted: 12/19/2021] [Indexed: 11/28/2022]
Abstract
Salmonella is a major foodborne pathogen and is responsible for a range of diseases. Not all Salmonella contribute to severe health outcomes as there is a large degree of genetic heterogeneity among the 2600 serovars within the genus. This variability across Salmonella serovars is linked to numerous genetic elements that dictate virulence. While several genetic elements encode virulence factors with well documented contributions to pathogenesis, many genetic elements implicated in Salmonella virulence remain uncharacterized. Many pathogens encode a family of E3 ubiquitin ligases that are delivered into the cells that they infect using a Type 3 Secretion System (T3SS). These effectors, known as NEL-domain E3s, were first characterized in Salmonella. Most Salmonella encode the NEL-effectors sspH2 and slrP, whereas only a subset of Salmonella encode sspH1. SspH1 has been shown to ubiquitinate the mammalian protein kinase PKN1, which has been reported to negatively regulate the pro-survival program Akt. We discovered that SspH1 mediates the degradation of PKN1 during infection of a macrophage cell line but that this degradation does not impact Akt signaling. Genomic analysis of a large collection of Salmonella genomes identified a putative new gene, sspH3, with homology to sspH1. SspH3 is a novel NEL-domain effector.
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Affiliation(s)
- Adrian Herod
- Department of Microbiology and Immunology, Dalhousie University Halifax, Halifax, NS, B3H 4R2, Canada
| | | | - Sandeep Tamber
- Microbiology Research Division, Bureau of Microbial Hazards, Health Canada, Ottawa, ON, Canada
| | - Lawrence Goodridge
- Food Science Department, University of Guelph, East Guelph, ON, N1G 2W1, Canada
| | - Roger C Lévesque
- Institute for Integrative and Systems Biology, Université Laval, Québec City, QC, G1V 0A6, Canada
| | - John Rohde
- Department of Microbiology and Immunology, Dalhousie University Halifax, Halifax, NS, B3H 4R2, Canada
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10
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Askoura M, Almalki AJ, Lila ASA, Almansour K, Alshammari F, Khafagy ES, Ibrahim TS, Hegazy WAH. Alteration of Salmonella enterica Virulence and Host Pathogenesis through Targeting sdiA by Using the CRISPR-Cas9 System. Microorganisms 2021; 9:microorganisms9122564. [PMID: 34946165 PMCID: PMC8707642 DOI: 10.3390/microorganisms9122564] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 12/08/2021] [Accepted: 12/09/2021] [Indexed: 01/31/2023] Open
Abstract
Salmonella enterica is a common cause of many enteric infections worldwide and is successfully engineered to deliver heterologous antigens to be used as vaccines. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs) RNA-guided Cas9 endonuclease is a promising genome editing tool. In the current study, a CRISPR-Cas9 system was used to target S.enterica sdiA that encodes signal molecule receptor SdiA and responds to the quorum sensing (QS) signaling compounds N-acylhomoserine lactones (AHLs). For this purpose, sdiA was targeted in both S.enterica wild type (WT) and the ΔssaV mutant strain, where SsaV has been reported to be an essential component of SPI2-T3SS. The impact of sdiA mutation on S. enterica virulence was evaluated at both early invasion and later intracellular replication in both the presence and absence of AHL. Additionally, the influence of sdiA mutation on the pathogenesis S. enterica WT and mutants was investigated in vivo, using mice infection model. Finally, the minimum inhibitory concentrations (MICs) of various antibiotics against S. enterica strains were determined. Present findings show that mutation in sdiA significantly affects S.enterica biofilm formation, cell adhesion and invasion. However, sdiA mutation did not affect bacterial intracellular survival. Moreover, in vivo bacterial pathogenesis was markedly lowered in S.enterica ΔsdiA in comparison with the wild-type strain. Significantly, double-mutant sdiA and ssaV attenuated the S. enterica virulence and in vivo pathogenesis. Moreover, mutations in selected genes increased Salmonella susceptibility to tested antibiotics, as revealed by determining the MICs and MBICs of these antibiotics. Altogether, current results clearly highlight the importance of the CRISPR-Cas9 system as a bacterial genome editing tool and the valuable role of SdiA in S.enterica virulence. The present findings extend the understanding of virulence regulation and host pathogenesis of Salmonellaenterica.
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Affiliation(s)
- Momen Askoura
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt
- Correspondence: (M.A.); (W.A.H.H.); Tel.: +20-1125226642 (M.A.); +20-1101188800 (W.A.H.H.)
| | - Ahmad J. Almalki
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (A.J.A.); (T.S.I.)
- Center of Excellence for Drug Research and Pharmaceutical Industries, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Amr S. Abu Lila
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt;
- Department of Pharmaceutics, College of Pharmacy, University of Hail, Hail 81442, Saudi Arabia; (K.A.); (F.A.)
| | - Khaled Almansour
- Department of Pharmaceutics, College of Pharmacy, University of Hail, Hail 81442, Saudi Arabia; (K.A.); (F.A.)
| | - Farhan Alshammari
- Department of Pharmaceutics, College of Pharmacy, University of Hail, Hail 81442, Saudi Arabia; (K.A.); (F.A.)
| | - El-Sayed Khafagy
- Department of Pharmaceutics, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Al-kharj 11942, Saudi Arabia;
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Suez Canal University, Ismailia 41552, Egypt
| | - Tarek S. Ibrahim
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (A.J.A.); (T.S.I.)
| | - Wael A. H. Hegazy
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt
- Correspondence: (M.A.); (W.A.H.H.); Tel.: +20-1125226642 (M.A.); +20-1101188800 (W.A.H.H.)
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11
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Isolation and molecular characterization of multidrug-resistant Salmonella enterica serovars. J Infect Public Health 2021; 14:1767-1776. [PMID: 34690097 DOI: 10.1016/j.jiph.2021.10.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 10/04/2021] [Accepted: 10/10/2021] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Salmonellosis is a foodborne zoonosis leaving gastrointestinal illness and drug-resistant genes to the consumers. To prevent Salmonella contamination associated health issues in the chicken meat sold in Riyadh city in Saudi Arabia. The evaluation of the Salmonella isolates from the meat sample needs to be screened for the composition of Salmonella serotypes and antimicrobial resistance pattern at the molecular level. METHODS AND RESULTS Using specific growth media for Salmonella spp., swabs taken from the whole-body surfaces of 200 chilled broiler chickens from different vendors in the city of Riyadh, were screened for Salmonella contamination. Biochemical and molecular characterization of the isolates showed the presence of the serovars, Salmonella enterica, Salmonella Enteritidis, S. Typhimurium, S. Kentucky, and S. Tennessee. The isolated serovars exhibited multidrug resistance [MDR] resistance to antibiotics. Molecular characterization of the different serovars shows the presence of sixteen drug-resistant genes. The drug resistance mechanism at the molecular level varied with serotypes according to the nature of the antibiotics they encountered. A comparative study of the nature of the drug-resistant gene and the common antibiotics used in poultry farming in that province matches much, indicating adaptive variation in S. enterica serotypes to survive in the host's gut biome. The resistance genes from the chicken meat have every chance to get into the human system. The native microbes in consumers may acquire drug-resistant genes from S. entericus serovars. Such conditions may lead to treatment complications in the hosts. CONCLUSIONS The results indicated that Salmonella infections constituted a potential risk to consumers through chicken flocks and noted that the genotypic resistance pattern to antibiotics draws attention in terms of both human and animal health. Also, promote other options for poultry farming, avoiding antibiotics supplementation.
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Selvaraj C, Vierra M, Dinesh DC, Abhirami R, Singh SK. Structural insights of macromolecules involved in bacteria-induced apoptosis in the pathogenesis of human diseases. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2021; 126:1-38. [PMID: 34090612 DOI: 10.1016/bs.apcsb.2021.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Numbers of pathogenic bacteria can induce apoptosis in human host cells and modulate the cellular pathways responsible for inducing or inhibiting apoptosis. These pathogens are significantly recognized by host proteins and provoke the multitude of several signaling pathways and alter the cellular apoptotic stimuli. This process leads the bacterial entry into the mammalian cells and evokes a variety of responses like phagocytosis, release of mitochondrial cytochrome c, secretion of bacterial effectors, release of both apoptotic and inflammatory cytokines, and the triggering of apoptosis. Several mechanisms are involved in bacteria-induced apoptosis including, initiation of the endogenous death machinery, pore-forming proteins, and secretion of superantigens. Either small molecules or proteins may act as a binding partner responsible for forming the protein complexes and regulate enzymatic activity via protein-protein interactions. The bacteria induce apoptosis, attack the human cell and gain control over various types of cells and tissue. Since these processes are intricate in the defense mechanisms of host organisms against pathogenic bacteria and play an important function in host-pathogen interactions. In this chapter, we focus on the various bacterial-induced apoptosis mechanisms in host cells and discuss the important proteins and bacterial effectors that trigger the host cell apoptosis. The structural characterization of bacterial effector proteins and their interaction with human host cells are also considered.
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Affiliation(s)
- Chandrabose Selvaraj
- Computer Aided Drug Design and Molecular Modeling Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi, Tamil Nadu, India.
| | - Marisol Vierra
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI, United States
| | | | - Rajaram Abhirami
- Computer Aided Drug Design and Molecular Modeling Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi, Tamil Nadu, India
| | - Sanjeev Kumar Singh
- Computer Aided Drug Design and Molecular Modeling Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi, Tamil Nadu, India.
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13
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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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Askoura M, Hegazy WAH. Ciprofloxacin interferes with Salmonella Typhimurium intracellular survival and host virulence through repression of Salmonella pathogenicity island-2 (SPI-2) genes expression. Pathog Dis 2020; 78:5743416. [PMID: 32083661 DOI: 10.1093/femspd/ftaa011] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 02/19/2020] [Indexed: 01/12/2023] Open
Abstract
Current study aims to characterize the influence of sub-minimum inhibitory concentration (sub-MIC) of ciprofloxacin on Salmonella intracellular survival and host virulence. Herein, Salmonella resistance patterns to various antibiotics were in agreement with those reported in previous studies. Moreover, intracellular survival of both ciprofloxacin-sensitive and -resistant Salmonella was markedly reduced upon treatment with sub-MIC of ciprofloxacin as determined by gentamicin protection assay. These findings were further confirmed using immunostaining indicating an inhibitory effect of sub-MIC of ciprofloxacin on Salmonella intracellular survival. RT-qPCR revealed that expression of genes encoding Salmonella type three secretion system (TTSS) decreased upon bacterial exposure to sub-MIC of ciprofloxacin. Furthermore, bacterial exposure to sub-MIC of ciprofloxacin significantly reduced expression of both sifA and sifB, which are important for Salmonella filaments formation within the host. Treatment of Salmonella with sub-MIC of ciprofloxacin reduced bacterial capacity to kill mice infection models. A lower mortality rate was observed in mice injected with Salmonella treated with sub-MIC of ciprofloxacin as compared with mice inoculated with untreated bacteria. Collectively, current findings indicate that, in addition to its bactericidal potential, sub-MIC of ciprofloxacin could inhibit Salmonella intracellular survival, virulence genes expression as well as host pathogenesis, providing another mechanism for ciprofloxacin in limiting Salmonella host infection.
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Affiliation(s)
- Momen Askoura
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
| | - Wael Abdel Halim Hegazy
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt.,Department of Pharmaceutics, College of Pharmacy, University of Florida, USA
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Hotinger JA, May AE. Animal Models of Type III Secretion System-Mediated Pathogenesis. Pathogens 2019; 8:pathogens8040257. [PMID: 31766664 PMCID: PMC6963218 DOI: 10.3390/pathogens8040257] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 11/18/2019] [Accepted: 11/20/2019] [Indexed: 01/22/2023] Open
Abstract
The type III secretion system (T3SS) is a conserved virulence factor used by many Gram-negative pathogenic bacteria and has become an important target for anti-virulence drugs. Most T3SS inhibitors to date have been discovered using in vitro screening assays. Pharmacokinetics and other important characteristics of pharmaceuticals cannot be determined with in vitro assays alone. In vivo assays are required to study pathogens in their natural environment and are an important step in the development of new drugs and vaccines. Animal models are also required to understand whether T3SS inhibition will enable the host to clear the infection. This review covers selected animal models (mouse, rat, guinea pig, rabbit, cat, dog, pig, cattle, primates, chicken, zebrafish, nematode, wax moth, flea, fly, and amoeba), where T3SS activity and infectivity have been studied in relation to specific pathogens (Escherichia coli, Salmonella spp., Pseudomonas spp., Shigella spp., Bordetella spp., Vibrio spp., Chlamydia spp., and Yersinia spp.). These assays may be appropriate for those researching T3SS inhibition.
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Staes I, Passaris I, Cambré A, Aertsen A. Population heterogeneity tactics as driving force in Salmonella virulence and survival. Food Res Int 2019; 125:108560. [DOI: 10.1016/j.foodres.2019.108560] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 07/05/2019] [Accepted: 07/12/2019] [Indexed: 01/28/2023]
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17
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Yang S, Deng Q, Sun L, Dong K, Li Y, Wu S, Huang R. Salmonella effector SpvB interferes with intracellular iron homeostasis via regulation of transcription factor NRF2. FASEB J 2019; 33:13450-13464. [PMID: 31569998 DOI: 10.1096/fj.201900883rr] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Iron is a necessary nutrient for humans and nearly all bacterial species. During Salmonella infection, macrophages limit the availability of iron to intracellular pathogens in one of the central components of nutritional immunity. However, Salmonella also have mechanisms to interfere with the antimicrobial effect of host iron withdrawal and meet their own nutrient requirements by scavenging iron from the host. Here, we provide what is, to our knowledge, the first report that SpvB, a pSLT-encoded cytotoxic protein whose function is associated with the intracellular stage of salmonellosis, perturbs macrophage iron metabolism, thereby facilitating Salmonella survival and intracellular replication. In investigating the underlying mechanism, we observed that the Salmonella effector SpvB down-regulated nuclear factor erythroid-derived 2-related factor 2 (NRF2), and its C-terminal domain was necessary and sufficient for NRF2 degradation via the proteasome pathway. Decreased NRF2 expression in the nucleus resulted in a decrease in its transcriptional target ferroportin, encoding the sole macrophage iron exporter, thus ultimately decreasing iron efflux and increasing the intracellular iron content. Additionally, SpvB contributes to the pathogenesis of Salmonella including severe serum hypoferremia, increased splenic and hepatic bacterial burden, and inflammatory injury in vivo. Together, our observations uncovered a novel contribution of SpvB to Salmonella pathology via interference with host intracellular iron metabolism.-Yang, S., Deng, Q., Sun, L., Dong, K., Li, Y., Wu, S., Huang, R. Salmonella effector SpvB interferes with intracellular iron homeostasis via regulation of transcription factor NRF2.
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Affiliation(s)
- Sidi Yang
- Department of Medical Microbiology, Medical College, Soochow University, Suzhou, China
| | - Qifeng Deng
- Department of Medical Microbiology, Medical College, Soochow University, Suzhou, China
| | - Lanqing Sun
- Department of Medical Microbiology, Medical College, Soochow University, Suzhou, China
| | - Kedi Dong
- Department of Medical Microbiology, Medical College, Soochow University, Suzhou, China
| | - Yuanyuan Li
- Department of Medical Microbiology, Medical College, Soochow University, Suzhou, China
| | - Shuyan Wu
- Department of Medical Microbiology, Medical College, Soochow University, Suzhou, China
| | - Rui Huang
- Department of Medical Microbiology, Medical College, Soochow University, Suzhou, China
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Passaris I, Cambré A, Govers SK, Aertsen A. Bimodal Expression of the Salmonella Typhimurium spv Operon. Genetics 2018; 210:621-635. [PMID: 30143595 PMCID: PMC6216589 DOI: 10.1534/genetics.118.300822] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 08/14/2018] [Indexed: 02/03/2023] Open
Abstract
The well-studied spv operon of Salmonellatyphimurium is important for causing full virulence in mice and both the regulation and function of the Spv proteins have been characterized extensively over the past several decades. Using quantitative single-cell fluorescence microscopy, we demonstrate the spv regulon to display a bimodal expression pattern that originates in the bimodal expression of the SpvR activator. The spv expression pattern is influenced by growth conditions and the specific Styphimurium strain used, but does not require Salmonella-specific virulence regulators. By monitoring real-time promoter kinetics, we reveal that SpvA has the ability to impart negative feedback on spvABCD expression without affecting spvR expression. Together, our data suggest that the SpvA protein counteracts the positive feedback loop imposed by SpvR, and could thus be responsible for dampening spvABCD expression and coordinating virulence protein production in time. The results presented here yield new insights in the intriguing regulation of the spv operon and adds this operon to the growing list of virulence factors exhibiting marked expression heterogeneity in Styphimurium.
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Affiliation(s)
- Ioannis Passaris
- Department of Microbial and Molecular Systems (MS), Katholieke Universiteit Leuven, 3001 Leuven, Belgium
| | - Alexander Cambré
- Department of Microbial and Molecular Systems (MS), Katholieke Universiteit Leuven, 3001 Leuven, Belgium
| | - Sander K Govers
- Department of Microbial and Molecular Systems (MS), Katholieke Universiteit Leuven, 3001 Leuven, Belgium
| | - Abram Aertsen
- Department of Microbial and Molecular Systems (MS), Katholieke Universiteit Leuven, 3001 Leuven, Belgium
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19
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Jennings E, Thurston TL, Holden DW. Salmonella SPI-2 Type III Secretion System Effectors: Molecular Mechanisms And Physiological Consequences. Cell Host Microbe 2017; 22:217-231. [DOI: 10.1016/j.chom.2017.07.009] [Citation(s) in RCA: 202] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 06/14/2017] [Accepted: 07/19/2017] [Indexed: 11/30/2022]
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Corthésy B, Bioley G. Gas-filled microbubbles: Novel mucosal antigen-delivery system for induction of anti-pathogen's immune responses in the gut. Gut Microbes 2017; 8:511-519. [PMID: 28541767 PMCID: PMC5628650 DOI: 10.1080/19490976.2017.1334032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Despite important success in protecting individuals against many pathogenic infections, parenteral vaccination is not optimal to induce immunity at the site of pathogen entry, i.e. mucosal surfaces. Moreover, designing adequate delivery systems and safe adjuvants to overcome the inherent tolerogenic environment of the mucosal tissue is challenging, in particular in the gastrointestinal tract prone to antigen degradation. We recently demonstrated that intranasal administration of a Salmonella-derived antigen associated with gas-filled microbubbles induced specific Ab and T cell responses in the gut and was associated with a reduction in local and systemic bacterial load after oral Salmonella infection. Building on these promising data, the adequate choice of antigen(s) to be administered and how to make it suitable for possible human application are discussed. We additionally present novel data dealing with oral administration of microbubbles and describe research strategies to direct them to mucosal sampling/inductive sites.
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Affiliation(s)
- Blaise Corthésy
- R&D Laboratory, Division of Immunology and Allergy, University State Hospital (CHUV), Epalinges, Switzerland
| | - Gilles Bioley
- R&D Laboratory, Division of Immunology and Allergy, University State Hospital (CHUV), Epalinges, Switzerland,CONTACT Dr. Gilles Bioley R&D Laboratory, Division of Immunology and Allergy, University State Hospital (CHUV), CLE-D2–205, Chemin des Boveresses 155, 1066 Epalinges, Switzerland
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21
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Wael AHH, Hisham AA. Evaluation of the role of SsaV Salmonella pathogenicity island-2 dependent type III secretion system components on the virulence behavior of Salmonella enterica serovar Typhimurium. ACTA ACUST UNITED AC 2017. [DOI: 10.5897/ajb2016.15852] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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22
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Ubah O, Palliyil S. Monoclonal Antibodies and Antibody Like Fragments Derived from Immunised Phage Display Libraries. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1053:99-117. [PMID: 29549637 PMCID: PMC7120432 DOI: 10.1007/978-3-319-72077-7_6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Morbidity and mortality associated with infectious diseases are always on the rise, especially in poorer countries and in the aging population. The inevitable, but unpredictable emergence of new infectious diseases has become a global threat. HIV/AIDS, severe acute respiratory syndrome (SARS), and the more recent H1N1 influenza are only a few of the numerous examples of emerging infectious diseases in the modern era. However despite advances in diagnostics, therapeutics and vaccines, there is need for more specific, efficacious, cost-effective and less toxic treatment and preventive drugs. In this chapter, we discuss a powerful combinatorial technology in association with animal immunisation that is capable of generating biologic drugs with high affinity, efficacy and limited off-site toxicity, and diagnostic tools with great precision. Although time consuming, immunisation still remains the preferred route for the isolation of high-affinity antibodies and antibody-like fragments. Phage display is a molecular diversity technology that allows the presentation of large peptide and protein libraries on the surface of filamentous phage. The selection of binding fragments from phage display libraries has proven significant for routine isolation of invaluable peptides, antibodies, and antibody-like domains for diagnostic and therapeutic applications. Here we highlight the many benefits of combining immunisation with phage display in combating infectious diseases, and how our knowledge of antibody engineering has played a crucial role in fully exploiting these platforms in generating therapeutic and diagnostic biologics towards antigenic targets of infectious organisms.
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Affiliation(s)
- Obinna Ubah
- Scottish Biologics Facility, Elasmogen Ltd, Aberdeen, UK
| | - Soumya Palliyil
- Scottish Biologics Facility, University of Aberdeen, Aberdeen, UK.
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23
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Chu Y, Gao S, Wang T, Yan J, Xu G, Li Y, Niu H, Huang R, Wu S. A novel contribution of spvB to pathogenesis of Salmonella Typhimurium by inhibiting autophagy in host cells. Oncotarget 2016; 7:8295-309. [PMID: 26811498 PMCID: PMC4884993 DOI: 10.18632/oncotarget.6989] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 01/13/2016] [Indexed: 12/31/2022] Open
Abstract
Salmonella plasmid virulence genes (spv) are highly conserved in strains of clinically important Salmonella serovars. It is essential for Salmonella plasmid-correlated virulence, although the exact mechanism remains to be elucidated. Autophagy has been reported to play an important role in host immune responses limiting Salmonella infection. Our previous studies demonstrated that Salmonella conjugative plasmid harboring spv genes could enhance bacterial cytotoxicity by inhibiting autophagy. In the present study, we investigated whether spvB, which is one of the most important constituents of spv ORF could intervene in autophagy pathway. Murine macrophage-like cells J774A.1, human epithelial HeLa cells, and BALB/c mice infected with Salmonella Typhimurium wild type, mutant and complementary strains (carrying or free spvB or complemented only with ADP-ribosyltransferase activity of SpvB) were used in vitro and in vivo assay, respectively. To further explore the molecular mechanisms, both SpvB ectopic eukaryotic expression system and cells deficient in essential autophagy components by siRNA were generated. Results indicated that spvB could suppress autophagosome formation through its function in depolymerizing actin, and aggravate inflammatory injury of the host in response to S. Typhimurium infection. Our studies demonstrated virulence of spvB involving in inhibition of autophagic flux for the first time, which could provide novel insights into Salmonella pathogenesis, and have potential application to develop new antibacterial strategies for Salmonellosis.
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Affiliation(s)
- Yuanyuan Chu
- Department of Microbiology, Medical College of Soochow University, Suzhou, P. R. China
| | - Song Gao
- Department of Microbiology, Medical College of Soochow University, Suzhou, P. R. China
| | - Ting Wang
- Department of Microbiology, Medical College of Soochow University, Suzhou, P. R. China
| | - Jing Yan
- Department of Microbiology, Medical College of Soochow University, Suzhou, P. R. China
| | - Guangmei Xu
- Department of Microbiology, Medical College of Soochow University, Suzhou, P. R. China
| | - Yuanyuan Li
- Department of Microbiology, Medical College of Soochow University, Suzhou, P. R. China
| | - Hua Niu
- Department of Microbiology, Medical College of Soochow University, Suzhou, P. R. China
| | - Rui Huang
- Department of Microbiology, Medical College of Soochow University, Suzhou, P. R. China
| | - Shuyan Wu
- Department of Microbiology, Medical College of Soochow University, Suzhou, P. R. China
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24
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Li YY, Wang T, Gao S, Xu GM, Niu H, Huang R, Wu SY. Salmonella plasmid virulence gene spvB enhances bacterial virulence by inhibiting autophagy in a zebrafish infection model. FISH & SHELLFISH IMMUNOLOGY 2016; 49:252-259. [PMID: 26723267 DOI: 10.1016/j.fsi.2015.12.033] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 11/26/2015] [Accepted: 12/21/2015] [Indexed: 06/05/2023]
Abstract
Salmonella enterica serovar typhimurium (S. typhimurium) is a facultative intracellular pathogen that can cause gastroenteritis and systemic infection in a wide range of hosts. Salmonella plasmid virulence gene spvB is closely related to bacterial virulence in different cells and animal models, and the encoded protein acts as an intracellular toxin required for ADP-ribosyl transferase activity. However, until now there is no report about the pathogenecity of spvB gene on zebrafish. Due to the outstanding advantages of zebrafish in analyzing bacteria-host interactions, a S. typhimurium infected zebrafish model was set up here to study the effect of spvB on autophagy and intestinal pathogenesis in vivo. We found that spvB gene could decrease the LD50 of S. typhimurium, and the strain carrying spvB promoted bacterial proliferation and aggravated the intestinal damage manifested by the narrowed intestines, fallen microvilli, blurred epithelium cell structure and infiltration of inflammatory cells. Results demonstrated the enhanced virulence induced by spvB in zebrafish. In spvB-mutant strain infected zebrafish, the levels of Lc3 turnover and Beclin1 expression increased, and the double-membraned autophagosome structures were observed, suggesting that spvB can inhibit autophagy activity. In summary, our results indicate that S. typhimurium strain containing spvB displays more virulence, triggering an increase in bacterial survival and intestine injuries by suppressing autophagy for the first time. This model provides novel insights into the role of Salmonella plasmid virulence gene in bacterial pathogenesis, and can help to further elucidate the relationship between bacteria and host immune response.
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Affiliation(s)
- Yuan-Yuan Li
- School of Biology & Basic Medical Sciences, Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, Jiangsu 215123, PR China
| | - Ting Wang
- School of Biology & Basic Medical Sciences, Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, Jiangsu 215123, PR China
| | - Song Gao
- School of Biology & Basic Medical Sciences, Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, Jiangsu 215123, PR China
| | - Guang-Mei Xu
- School of Biology & Basic Medical Sciences, Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, Jiangsu 215123, PR China
| | - Hua Niu
- School of Biology & Basic Medical Sciences, Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, Jiangsu 215123, PR China
| | - Rui Huang
- School of Biology & Basic Medical Sciences, Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, Jiangsu 215123, PR China
| | - Shu-Yan Wu
- School of Biology & Basic Medical Sciences, Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, Jiangsu 215123, PR China.
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Abstract
Salmonellae invasion and intracellular replication within host cells result in a range of diseases, including gastroenteritis, bacteraemia, enteric fever and focal infections. In recent years, considerable progress has been made in our understanding of the molecular mechanisms that salmonellae use to alter host cell physiology; through the delivery of effector proteins with specific activities and through the modulation of defence and stress response pathways. In this Review, we summarize our current knowledge of the complex interplay between bacterial and host factors that leads to inflammation, disease and, in most cases, control of the infection by its animal hosts, with a particular focus on Salmonella enterica subsp. enterica serovar Typhimurium. We also highlight gaps in our knowledge of the contributions of salmonellae and the host to disease pathogenesis, and we suggest future avenues for further study.
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Affiliation(s)
- Doris L. LaRock
- Department of Microbiology, University of Washington, Seattle, WA 98195
| | - Anu Chaudhary
- Department of Microbiology, University of Washington, Seattle, WA 98195
| | - Samuel I. Miller
- Department of Microbiology, University of Washington, Seattle, WA 98195
- Department of Genome Sciences, University of Washington, Seattle, WA 98195
- Department of Immunology, University of Washington, Seattle, WA 98195
- Department of Medicine, University of Washington, Seattle, WA 98195
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26
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Wall DM, McCormick BA. Bacterial secreted effectors and caspase-3 interactions. Cell Microbiol 2014; 16:1746-56. [PMID: 25262664 PMCID: PMC4257569 DOI: 10.1111/cmi.12368] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 09/10/2014] [Accepted: 09/15/2014] [Indexed: 12/29/2022]
Abstract
Apoptosis is a critical process that intrinsically links organism survival to its ability to induce controlled death. Thus, functional apoptosis allows organisms to remove perceived threats to their survival by targeting those cells that it determines pose a direct risk. Central to this process are apoptotic caspases, enzymes that form a signalling cascade, converting danger signals via initiator caspases into activation of the executioner caspase, caspase-3. This enzyme begins disassembly of the cell by activating DNA degrading enzymes and degrading the cellular architecture. Interaction of pathogenic bacteria with caspases, and in particular, caspase-3, can therefore impact both host cell and bacterial survival. With roles outside cell death such as cell differentiation, control of signalling pathways and immunomodulation also being described for caspase-3, bacterial interactions with caspase-3 may be of far more significance in infection than previously recognized. In this review, we highlight the ways in which bacterial pathogens have evolved to subvert caspase-3 both through effector proteins that directly interact with the enzyme or by modulating pathways that influence its activation and activity.
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Affiliation(s)
- Daniel M Wall
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, G12 8QQ, UK
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Mesa-Pereira B, Medina C, Camacho EM, Flores A, Santero E. Novel tools to analyze the function of Salmonella effectors show that SvpB ectopic expression induces cell cycle arrest in tumor cells. PLoS One 2013; 8:e78458. [PMID: 24205236 PMCID: PMC3804527 DOI: 10.1371/journal.pone.0078458] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 09/12/2013] [Indexed: 01/26/2023] Open
Abstract
In order to further characterize its role in pathogenesis and to establish whether its overproduction can lead to eukaryotic tumor cell death, Salmonella strains able to express its virulence factor SpvB (an ADP-ribosyl transferase enzyme) in a salicylate-inducible way have been constructed and analyzed in different eukaryotic tumor cell lines. To do so, the bacterial strains bearing the expression system have been constructed in a ∆purD background, which allows control of bacterial proliferation inside the eukaryotic cell. In the absence of bacterial proliferation, salicylate-induced SpvB production resulted in activation of caspases 3 and 7 and apoptotic cell death. The results clearly indicated that controlled SpvB production leads to F-actin depolimerization and either G1/S or G2/M phase arrest in all cell lines tested, thus shedding light on the function of SpvB in Salmonella pathogenesis. In the first place, the combined control of protein production by salicylate regulated vectors and bacterial growth by adenine concentration offers the possibility to study the role of Salmonella effectors during eukaryotic cells infection. In the second place, the salicylate-controlled expression of SpvB by the bacterium provides a way to evaluate the potential of other homologous or heterologous proteins as antitumor agents, and, eventually to construct novel potential tools for cancer therapy, given that Salmonella preferentially proliferates in tumors.
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Affiliation(s)
- Beatriz Mesa-Pereira
- Centro Andaluz de Biología del Desarrollo/ CSIC/ Universidad Pablo de Olavide/ Junta de Andalucía. Departamento de Biología Molecular e Ingeniería Bioquímica, Seville, Spain
| | - Carlos Medina
- Centro Andaluz de Biología del Desarrollo/ CSIC/ Universidad Pablo de Olavide/ Junta de Andalucía. Departamento de Biología Molecular e Ingeniería Bioquímica, Seville, Spain
| | - Eva María Camacho
- Centro Andaluz de Biología del Desarrollo/ CSIC/ Universidad Pablo de Olavide/ Junta de Andalucía. Departamento de Biología Molecular e Ingeniería Bioquímica, Seville, Spain
| | - Amando Flores
- Centro Andaluz de Biología del Desarrollo/ CSIC/ Universidad Pablo de Olavide/ Junta de Andalucía. Departamento de Biología Molecular e Ingeniería Bioquímica, Seville, Spain
- * E-mail:
| | - Eduardo Santero
- Centro Andaluz de Biología del Desarrollo/ CSIC/ Universidad Pablo de Olavide/ Junta de Andalucía. Departamento de Biología Molecular e Ingeniería Bioquímica, Seville, Spain
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28
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Kidwai AS, Mushamiri I, Niemann GS, Brown RN, Adkins JN, Heffron F. Diverse secreted effectors are required for Salmonella persistence in a mouse infection model. PLoS One 2013; 8:e70753. [PMID: 23950998 PMCID: PMC3741292 DOI: 10.1371/journal.pone.0070753] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2013] [Accepted: 06/26/2013] [Indexed: 01/08/2023] Open
Abstract
Salmonella enterica serovar Typhimurium causes typhoid-like disease in mice and is a model of typhoid fever in humans. One of the hallmarks of typhoid is persistence, the ability of the bacteria to survive in the host weeks after infection. Virulence factors called effectors facilitate this process by direct transfer to the cytoplasm of infected cells thereby subverting cellular processes. Secretion of effectors to the cell cytoplasm takes place through multiple routes, including two separate type III secretion (T3SS) apparati as well as outer membrane vesicles. The two T3SS are encoded on separate pathogenicity islands, SPI-1 and -2, with SPI-1 more strongly associated with the intestinal phase of infection, and SPI-2 with the systemic phase. Both T3SS are required for persistence, but the effectors required have not been systematically evaluated. In this study, mutations in 48 described effectors were tested for persistence. We replaced each effector with a specific DNA barcode sequence by allelic exchange and co-infected with a wild-type reference to calculate the ratio of wild-type parent to mutant at different times after infection. The competitive index (CI) was determined by quantitative PCR in which primers that correspond to the barcode were used for amplification. Mutations in all but seven effectors reduced persistence demonstrating that most effectors were required. One exception was CigR, a recently discovered effector that is widely conserved throughout enteric bacteria. Deletion of cigR increased lethality, suggesting that it may be an anti-virulence factor. The fact that almost all Salmonella effectors are required for persistence argues against redundant functions. This is different from effector repertoires in other intracellular pathogens such as Legionella.
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Affiliation(s)
- Afshan S. Kidwai
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Ivy Mushamiri
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - George S. Niemann
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Roslyn N. Brown
- Center for Bioproducts and Bioenergy, Washington State University, Richland, Washington, United States of America
| | - Joshua N. Adkins
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | - Fred Heffron
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, United States of America
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29
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Identification of salmonella pathogenicity island-2 type III secretion system effectors involved in intramacrophage replication of S. enterica serovar typhimurium: implications for rational vaccine design. mBio 2013; 4:e00065. [PMID: 23592259 PMCID: PMC3634603 DOI: 10.1128/mbio.00065-13] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
Salmonella enterica serovars cause severe diseases in humans, such as gastroenteritis and typhoid fever. The development of systemic disease is dependent on a type III secretion system (T3SS) encoded by Salmonella pathogenicity island-2 (SPI-2). Translocation of effector proteins across the Salmonella-containing vacuole, via the SPI-2 T3SS, enables bacterial replication within host cells, including macrophages. Here, we investigated the contribution of these effectors to intramacrophage replication of Salmonella enterica serovar Typhimurium using Fluorescence Dilution, a dual-fluorescence tool which allows direct measurement of bacterial replication. Of 32 strains, each carrying single mutations in genes encoding effectors, 10 (lacking sifA, sseJ, sopD2, sseG, sseF, srfH, sseL, spvD, cigR, or steD) were attenuated in replication in mouse bone marrow-derived macrophages. The replication profiles of strains combining deletions in effector genes were also investigated: a strain lacking the genes sseG, sopD2, and srfH showed an increased replication defect compared to single-mutation strains and was very similar to SPI-2 T3SS-deficient bacteria with respect to its replication defect. This strain was substantially attenuated in virulence in vivo and yet retained intracellular vacuole integrity and a functional SPI-2 T3SS. Moreover, this strain was capable of SPI-2 T3SS-mediated delivery of a model antigen for major histocompatibility complex (MHC) class I-dependent T-cell activation. This work establishes a basis for the use of a poly-effector mutant strain as an attenuated vaccine carrier for delivery of heterologous antigens directly into the cytoplasm of host cells. Live attenuated strains of Salmonella enterica serotype Typhi have generated much interest in the search for improved vaccines against typhoid fever and as vaccine vectors for the delivery of heterologous antigens. A promising vaccine candidate is the ΔaroC ΔssaV S. Typhi strain, which owes its attenuation mainly to lack of a type III secretion system (SPI-2 T3SS). The SPI-2 T3SS is important for bacterial proliferation inside macrophages, but not all of the effectors involved in this process have been identified. Here, we show that 10 effectors of the related strain S. Typhimurium contribute to intracellular replication in macrophages. Moreover, we establish that a poly-effector mutant strain of S. Typhimurium can have a severe replication defect and maintain a functional SPI-2 T3SS, which can be exploited for delivery of heterologous antigens.
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Diard M, Garcia V, Maier L, Remus-Emsermann MNP, Regoes RR, Ackermann M, Hardt WD. Stabilization of cooperative virulence by the expression of an avirulent phenotype. Nature 2013; 494:353-6. [PMID: 23426324 DOI: 10.1038/nature11913] [Citation(s) in RCA: 222] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2012] [Accepted: 01/16/2013] [Indexed: 12/13/2022]
Abstract
Pathogens often infect hosts through collective actions: they secrete growth-promoting compounds or virulence factors, or evoke host reactions that fuel the colonization of the host. Such behaviours are vulnerable to the rise of mutants that benefit from the collective action without contributing to it; how these behaviours can be evolutionarily stable is not well understood. We address this question using the intestinal pathogen Salmonella enterica serovar Typhimurium (hereafter termed S. typhimurium), which manipulates its host to induce inflammation, and thereby outcompetes the commensal microbiota. Notably, the virulence factors needed for host manipulation are expressed in a bistable fashion, leading to a slow-growing subpopulation that expresses virulence genes, and a fast-growing subpopulation that is phenotypically avirulent. Here we show that the expression of the genetically identical but phenotypically avirulent subpopulation is essential for the evolutionary stability of virulence in this pathogen. Using a combination of mathematical modelling, experimental evolution and competition experiments we found that within-host evolution leads to the emergence of mutants that are genetically avirulent and fast-growing. These mutants are defectors that exploit inflammation without contributing to it. In infection experiments initiated with wild-type S. typhimurium, defectors increase only slowly in frequency. In a genetically modified S. typhimurium strain in which the phenotypically avirulent subpopulation is reduced in size, defectors rise more rapidly, inflammation ceases prematurely, and S. typhimurium is quickly cleared from the gut. Our results establish that host manipulation by S. typhimurium is a cooperative trait that is vulnerable to the rise of avirulent defectors; the expression of a phenotypically avirulent subpopulation that grows as fast as defectors slows down this process, and thereby promotes the evolutionary stability of virulence. This points to a key role of bistable virulence gene expression in stabilizing cooperative virulence and may lead the way to new approaches for controlling pathogens.
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Affiliation(s)
- Médéric Diard
- Institute of Microbiology, ETH Zurich, Wolfgang-Pauli-Str. 10, 8093 Zurich, Switzerland
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31
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Ramos-Morales F. Impact of Salmonella enterica Type III Secretion System Effectors on the Eukaryotic Host Cell. ACTA ACUST UNITED AC 2012. [DOI: 10.5402/2012/787934] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Type III secretion systems are molecular machines used by many Gram-negative bacterial pathogens to inject proteins, known as effectors, directly into eukaryotic host cells. These proteins manipulate host signal transduction pathways and cellular processes to the pathogen’s advantage. Salmonella enterica possesses two virulence-related type III secretion systems that deliver more than forty effectors. This paper reviews our current knowledge about the functions, biochemical activities, host targets, and impact on host cells of these effectors. First, the concerted action of effectors at the cellular level in relevant aspects of the interaction between Salmonella and its hosts is analyzed. Then, particular issues that will drive research in the field in the near future are discussed. Finally, detailed information about each individual effector is provided.
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Affiliation(s)
- Francisco Ramos-Morales
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes 6, 41012 Sevilla, Spain
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Shniffer A, Visschedyk DD, Ravulapalli R, Suarez G, Turgeon ZJ, Petrie AA, Chopra AK, Merrill AR. Characterization of an actin-targeting ADP-ribosyltransferase from Aeromonas hydrophila. J Biol Chem 2012; 287:37030-41. [PMID: 22969084 DOI: 10.1074/jbc.m112.397612] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The mono-ADP-ribosyltransferase (mART) toxins are contributing factors to a number of human diseases, including cholera, diphtheria, traveler's diarrhea, and whooping cough. VahC is a cytotoxic, actin-targeting mART from Aeromonas hydrophila PPD134/91. This bacterium is implicated primarily in diseases among freshwater fish species but also contributes to gastrointestinal and extraintestinal infections in humans. VahC was shown to ADP-ribosylate Arg-177 of actin, and the kinetic parameters were K(m)(NAD(+)) = 6 μM, K(m)(actin) = 24 μM, and k(cat) = 22 s(-1). VahC activity caused depolymerization of actin filaments, which induced caspase-mediated apoptosis in HeLa Tet-Off cells. Alanine-scanning mutagenesis of predicted catalytic residues showed the predicted loss of in vitro mART activity and cytotoxicity. Bioinformatic and kinetic analysis also identified three residues in the active site loop that were critical for the catalytic mechanism. A 1.9 Å crystal structure supported the proposed roles of these residues and their conserved nature among toxin homologues. Several small molecules were characterized as inhibitors of in vitro VahC mART activity and suramin was the best inhibitor (IC(50) = 20 μM). Inhibitor activity was also characterized against two other actin-targeting mART toxins. Notably, these inhibitors represent the first report of broad spectrum inhibition of actin-targeting mART toxins.
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Affiliation(s)
- Adin Shniffer
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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Persson S, Jacobsen T, Olsen JE, Olsen KEP, Hansen F. A new real-time PCR method for the identification of Salmonella Dublin. J Appl Microbiol 2012; 113:615-21. [PMID: 22747740 DOI: 10.1111/j.1365-2672.2012.05378.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 06/13/2012] [Accepted: 06/20/2012] [Indexed: 11/28/2022]
Abstract
AIMS Development of a real-time PCR method for the specific detection of Salmonella Dublin. METHODS AND RESULTS The method was directed towards a Salm. Dublin-specific sequence of the vagC gene on the Salmonella virulence plasmid (pSDV) and towards Salmonella genus-specific sequence of the invA gene, serving as an internal amplification control. The method showed 100% inclusivity and exclusivity when tested on a strain collection containing 50 serotyped S . Dublin strains, 20 strains of other Salmonella serotypes and 10 non- Salmonella strains. The method also showed 100% inclusivity and 99% exclusivity in a collaborative study comprising eight laboratories, where each laboratory received ten different S . Dublin strains and 10 other Salmonella serotypes. CONCLUSIONS The method showed excellent performance both when validated in the laboratory and in the collaborative study. SIGNIFICANCE AND IMPACT OF THE STUDY Application of the present method in food control, for example at slaughterhouses, can improve the contamination control of this veterinary and clinically important Salmonella serotype.
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Affiliation(s)
- S Persson
- Department of Microbiological Diagnostics, Statens Serum Institut, Copenhagen, Denmark.
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Diarrhea and colitis in mice require the Salmonella pathogenicity island 2-encoded secretion function but not SifA or Spv effectors. Infect Immun 2012; 80:3360-70. [PMID: 22778101 DOI: 10.1128/iai.00404-12] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
We investigated the roles of Salmonella pathogenicity island 2 (SPI-2) and two SPI-2 effectors in Salmonella colitis and diarrhea in genetically resistant BALB/c.D2(Slc11a1) congenic mice with the wild-type Nramp1 locus. Wild-type Salmonella enterica serovar Typhimurium 14028s caused a pan-colitis, and the infected mice developed frank diarrhea with a doubling of the fecal water content. An ssaV mutant caused only a 26% increase in fecal water content, without producing the pathological changes of colitis, and it did not cause weight loss over a 1-week period of observation. However, two SPI-2 effector mutants, the spvB and sifA mutants, and a double spvB sifA mutant caused diarrhea and colitis, even though the sifA mutant was sensitive to killing by bone marrow-derived macrophages from BALB/c.D2 mice and was severely impaired in extraintestinal growth but not in growth in the cecum. These results demonstrate that systemic S. enterica infection and diarrhea/colitis are distinct pathogenic processes and that only the former requires spvB and sifA.
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35
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Garai P, Gnanadhas DP, Chakravortty D. Salmonella enterica serovars Typhimurium and Typhi as model organisms: revealing paradigm of host-pathogen interactions. Virulence 2012; 3:377-88. [PMID: 22722237 PMCID: PMC3478240 DOI: 10.4161/viru.21087] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The lifestyle of intracellular pathogens has always questioned the skill of a microbiologist in the context of finding the permanent cure to the diseases caused by them. The best tool utilized by these pathogens is their ability to reside inside the host cell, which enables them to easily bypass the humoral immunity of the host, such as the complement system. They further escape from the intracellular immunity, such as lysosome and inflammasome, mostly by forming a protective vacuole-bound niche derived from the host itself. Some of the most dreadful diseases are caused by these vacuolar pathogens, for example, tuberculosis by Mycobacterium or typhoid fever by Salmonella. To deal with such successful pathogens therapeutically, the knowledge of a host-pathogen interaction system becomes primarily essential, which further depends on the use of a model system. A well characterized pathogen, namely Salmonella, suits the role of a model for this purpose, which can infect a wide array of hosts causing a variety of diseases. This review focuses on various such aspects of research on Salmonella which are useful for studying the pathogenesis of other intracellular pathogens.
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Affiliation(s)
- Preeti Garai
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research and Biosafety Laboratories, Indian Institute of Science, Bangalore, India
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36
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Figueira R, Holden DW. Functions of the Salmonella pathogenicity island 2 (SPI-2) type III secretion system effectors. Microbiology (Reading) 2012; 158:1147-1161. [DOI: 10.1099/mic.0.058115-0] [Citation(s) in RCA: 253] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Affiliation(s)
- Rita Figueira
- Section of Microbiology, Centre for Molecular Microbiology and Infection, Imperial College London, Armstrong Road, London SW7 2AZ, UK
| | - David W. Holden
- Section of Microbiology, Centre for Molecular Microbiology and Infection, Imperial College London, Armstrong Road, London SW7 2AZ, UK
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37
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Kaiser P, Diard M, Stecher B, Hardt WD. The streptomycin mouse model for Salmonella diarrhea: functional analysis of the microbiota, the pathogen's virulence factors, and the host's mucosal immune response. Immunol Rev 2012; 245:56-83. [PMID: 22168414 DOI: 10.1111/j.1600-065x.2011.01070.x] [Citation(s) in RCA: 137] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The mammalian intestine is colonized by a dense microbial community, the microbiota. Homeostatic and symbiotic interactions facilitate the peaceful co-existence between the microbiota and the host, and inhibit colonization by most incoming pathogens ('colonization resistance'). However, if pathogenic intruders overcome colonization resistance, a fierce, innate inflammatory defense can be mounted within hours, the adaptive arm of the immune system is initiated, and the pathogen is fought back. The molecular nature of the homeostatic interactions, the pathogen's ability to overcome colonization resistance, and the triggering of native and adaptive mucosal immune responses are still poorly understood. To study these mechanisms, the streptomycin mouse model for Salmonella diarrhea is of great value. Here, we review how S. Typhimurium triggers mucosal immune responses by active (virulence factor elicited) and passive (MyD88-dependent) mechanisms and introduce the S. Typhimurium mutants available for focusing on either response. Interestingly, mucosal defense turns out to be a double-edged sword, limiting pathogen burdens in the gut tissue but enhancing pathogen growth in the gut lumen. This model allows not only studying the molecular pathogenesis of Salmonella diarrhea but also is ideally suited for analyzing innate defenses, microbe handling by mucosal phagocytes, adaptive secretory immunoglobulin A responses, probing microbiota function, and homeostatic microbiota-host interactions. Finally, we discuss the general need for defined assay conditions when using animal models for enteric infections and the central importance of littermate controls.
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Affiliation(s)
- Patrick Kaiser
- Institute of Microbiology, D-BIOL, ETH Zürich, Zürich, Switzerland
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38
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Morrison CM, Dial SM, Day WA, Joens LA. Investigations of Salmonella enterica serovar newport infections of oysters by using immunohistochemistry and knockout mutagenesis. Appl Environ Microbiol 2012; 78:2867-73. [PMID: 22307286 PMCID: PMC3318786 DOI: 10.1128/aem.07456-11] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Accepted: 01/23/2012] [Indexed: 11/20/2022] Open
Abstract
The consumption of raw oysters is an important risk factor in the acquisition of food-borne disease, with Salmonella being one of a number of pathogens that have been found in market oysters. Previous work by our lab found that Salmonella was capable of surviving in oysters for over 2 months under laboratory conditions, and this study sought to further investigate Salmonella's tissue affinity and mechanism of persistence within the oysters. Immunohistochemistry was used to show that Salmonella was capable of breaching the epithelial barriers, infecting the deeper connective tissues of the oysters, and evading destruction by the oysters' phagocytic hemocytes. To further investigate the mechanism of these infections, genes vital to the function of Salmonella's two main type III secretion systems were disrupted and the survivability of these knockout mutants within oysters was assayed. When the Salmonella pathogenicity island 1 and 2 mutant strains were exposed to oysters, there were no detectable deficiencies in their abilities to survive, suggesting that Salmonella's long-term infection of oysters does not rely upon these two important pathogenicity islands and must be due to some other, currently unknown, mechanism.
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Affiliation(s)
- Christopher M Morrison
- Department of Veterinary Science and Microbiology, The University of Arizona, Tucson, Arizona, USA
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39
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Guiney DG, Fierer J. The Role of the spv Genes in Salmonella Pathogenesis. Front Microbiol 2011; 2:129. [PMID: 21716657 PMCID: PMC3117207 DOI: 10.3389/fmicb.2011.00129] [Citation(s) in RCA: 137] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 05/25/2011] [Indexed: 11/30/2022] Open
Abstract
Salmonella strains cause three main types of diseases in people: gastroenteritis, enteric (typhoid) fever, and non-typhoid extra-intestinal disease with bacteremia. Genetic analysis indicates that each clinical syndrome requires distinct sets of virulence genes, and Salmonella isolates differ in their constellation of virulence traits. The spv locus is strongly associated with strains that cause non-typhoid bacteremia, but are not present in typhoid strains. The spv region contains three genes required for the virulence phenotype in mice: the positive transcriptional regulator spvR and two structural genes spvB and spvC. SpvB and SpvC are translocated into the host cell by the Salmonella pathogenicity island-2 type-three secretion system. SpvB prevents actin polymerization by ADP-ribosylation of actin monomers, while SpvC has phosphothreonine lyase activity and has been shown to inhibit MAP kinase signaling. The exact mechanisms by which SpvB and SpvC act in concert to enhance virulence are still unclear. SpvB exhibits a cytotoxic effect on host cells and is required for delayed cell death by apoptosis following intracellular infection. Strains isolated from systemic infections of immune compromised patients, particularly HIV patients, usually carry the spv locus, strongly suggesting that CD4 T cells are required to control disease due to Salmonella that are spv positive. This association is not seen with typhoid fever, indicating that the pathogenesis and immunology of typhoid have fundamental differences from the syndrome of non-typhoid bacteremia.
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Affiliation(s)
- Donald G Guiney
- Department of Medicine, University of California San Diego School of Medicine La Jolla, CA, USA
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40
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Buckner MMC, Croxen MA, Arena ET, Finlay BB. A comprehensive study of the contribution of Salmonella enterica serovar Typhimurium SPI2 effectors to bacterial colonization, survival, and replication in typhoid fever, macrophage, and epithelial cell infection models. Virulence 2011; 2:208-16. [PMID: 21540636 DOI: 10.4161/viru.2.3.15894] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Salmonella enterica serovars are Gram-negative bacterial pathogens responsible for human diseases including gastroenteritis and typhoid fever. After ingestion, Salmonella cross the intestinal epithelial barrier, where they are phagocytosed by macrophages and dendritic cells, which then enables their spread to systemic sites during cases of typhoid fever. Salmonella use two type 3 secretion systems encoded by Salmonella pathogenicity islands (SPI) 1 and 2 to inject virulence proteins into host cells to modify cellular functions. SPI1 is involved in host cell invasion and inflammation, whereas SPI2 is required for intracellular survival and replication within phagocytes, and systemic spread. In this study the contribution of nearly all known SPI2 effectors was examined in an in vivo model of murine typhoid fever and cell culture models of macrophage and epithelial cell infection. Unmarked, in-frame deletions of SPI2 effectors were engineered in S. enterica serovar Typhimurium and the ability of the 16 different mutants to colonize and replicate was examined. In the typhoid model, we found that ΔspvB and ΔspiC mutants were attenuated for colonization of intestinal and systemic sites, while the ΔsseF mutant was attenuated in systemic organs. In epithelial cells, all mutants replicated to the same extent as the wild-type. In macrophages, ΔspiC, ΔsteC, ΔspvB, ΔssseK1/K2/K3, ΔsifA, and ΔsifB strains replicated poorly in comparison to wild-type Salmonella. This study provides a thorough screen of the majority of the known SPI2 effectors evaluated under the same conditions in various models of infection, providing a foundation for comparative examination of the roles and interactions of these effectors.
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Affiliation(s)
- Michelle M C Buckner
- Department of Microbiology and Immunology and Michael Smith Laboratories, University of British Columbia, Canada
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Alzogaray V, Danquah W, Aguirre A, Urrutia M, Berguer P, García Véscovi E, Haag F, Koch-Nolte F, Goldbaum FA. Single-domain llama antibodies as specific intracellular inhibitors of SpvB, the actin ADP-ribosylating toxin of Salmonella typhimurium. FASEB J 2010; 25:526-34. [PMID: 20940265 DOI: 10.1096/fj.10-162958] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
ADP-ribosylation of host cell proteins is a common mode of cell intoxication by pathogenic bacterial toxins. Antibodies induced by immunization with inactivated ADP-ribosylating toxins provide efficient protection in case of some secreted toxins, e.g., diphtheria and pertussis toxins. However, other ADP-ribosylating toxins, such as Salmonella SpvB toxin, are secreted directly from the Salmonella-containing vacuole into the cytosol of target cells via the SPI-2 encoded bacterial type III secretion system, and thus are inaccessible to conventional antibodies. Small-molecule ADP-ribosylation inhibitors are fraught with potential side effects caused by inhibition of endogenous ADP-ribosyltransferases. Here, we report the development of a single-domain antibody from an immunized llama that blocks the capacity of SpvB to ADP-ribosylate actin at a molar ratio of 1:1. The single-domain antibody, when expressed as an intrabody, effectively protected cells from the cytotoxic activity of a translocation-competent chimeric C2IN-C/SpvB toxin. Transfected cells were also protected against cytoskeletal alterations induced by wild-type SpvB-expressing strains of Salmonella. This proof of principle paves the way for developing new antidotes against intracellular toxins.
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Affiliation(s)
- Vanina Alzogaray
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires–Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires, Argentina
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42
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The inflammatory cytokine tumor necrosis factor modulates the expression of Salmonella typhimurium effector proteins. JOURNAL OF INFLAMMATION-LONDON 2010; 7:42. [PMID: 20704730 PMCID: PMC2925363 DOI: 10.1186/1476-9255-7-42] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Accepted: 08/12/2010] [Indexed: 01/26/2023]
Abstract
Tumor necrosis factor alpha (TNF-alpha)is a host inflammatory factor. Bacteria increase TNF-alpha expression in a variety of human diseases including infectious diseases, inflammatory bowel diseases, and cancer. It is unknown, however, how TNF-alpha directly modulates bacterial protein expression during intestinal infection and chronic inflammation. In the current study, we hypothesize that Salmonella typhimurium senses TNF-alpha and show that TNF-alpha treatment modulates Salmonella virulent proteins (called effectors), thus changing the host-bacterial interaction in intestinal epithelial cells. We investigated the expression of 23 Salmonella effectors after TNF-alpha exposure. We found that TNF-alpha treatment led to differential effector expression: effector SipA was increased by TNF-alpha treatment, whereas the expression levels of other effectors, including gogB and spvB, decreased in the presence of TNF-alpha. We verified the protein expression of Salmonella effectors AvrA and SipA by Western blots. Furthermore, we used intestinal epithelial cells as our experimental model to explore the response of human intestinal cells to TNF-alpha pretreated Salmonella. More bacterial invasion was found in host cells colonized with Salmonella strains pretreated with TNF-alpha compared to Salmonella without TNF-alpha treatment. TNF-alpha pretreated Salmonella induced higher proinflammatory JNK signalling responses compared to the Salmonella strains without TNF-alpha exposure. Exposure to TNF-alpha made Salmonella to induce more inflammatory cytokine IL-8 in intestinal epithelial cells. JNK inhibitor treatment was able to suppress the effects of TNF-pretreated-Salmonella in enhancing expressions of phosphorylated-JNK and c-jun and secretion of IL-8. Overall, our study provides new insights into Salmonella-host interactions in intestinal inflammation.
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Wu S, Li Y, Xu Y, Li Q, Chu Y, Huang R, Qin Z. A Salmonella enterica serovar Typhi plasmid induces rapid and massive apoptosis in infected macrophages. Cell Mol Immunol 2010; 7:271-8. [PMID: 20473323 DOI: 10.1038/cmi.2010.17] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
pR(ST98) is a chimeric plasmid isolated from Salmonella enterica serovar Typhi (S. typhi) that mediates the functions of drug resistance and virulence. Previously, we reported that Salmonella plasmid virulence (spv) genes were present in S. typhi. In our current study, we investigated whether plasmid pR(ST98) exhibits significant cytotoxicity in macrophages. pR(ST98) was transferred into the avirulent Salmonella enterica serovar Typhimurium (S. typhimurium) strain RIA to create the transconjugant pR(ST98)/RIA. The standard S. typhimurium virulent strain SR-11, which carries a 100-kb virulence plasmid, was used as a positive control. The bacterial strains were incubated with a murine macrophage-like cell line (J774A.1) in vitro. Apoptosis of J774A.1 cells was examined by electron microscopy and flow cytometry after annexin-V/propidium iodide labeling, and the survival of Salmonella strains in J774A.1 cells was determined. Results showed that macrophages infected with strain pR(ST98)/RIA displayed greater levels of apoptosis than those infected with RIA and that pR(ST98 )may increase bacterial survival in macrophages. Further studies showed that the pR(ST98)-induced death of macrophages was associated with the loss of mitochondrial membrane potential and that pR(ST98 )may activate caspase-9 and then caspase-3. The research data indicate that the virulence of bacteria that contain the pR(ST98) plasmid is enhanced; the presence of this plasmid increases the survival of the bacterial pathogen and acts through the mitochondrial pathway to mediate macrophage apoptosis.
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Affiliation(s)
- Shuyan Wu
- Medical College of Soochow University, Suzhou, China
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44
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Visschedyk DD, Perieteanu AA, Turgeon ZJ, Fieldhouse RJ, Dawson JF, Merrill AR. Photox, a novel actin-targeting mono-ADP-ribosyltransferase from Photorhabdus luminescens. J Biol Chem 2010; 285:13525-34. [PMID: 20181945 DOI: 10.1074/jbc.m109.077339] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Photorhabdus luminescens is a pathogenic bacterium that produces many toxic proteins. The mono-ADP-ribosyltransferases (mARTs) are an enzyme class produced by numerous pathogenic bacteria and participate in disease in plants and animals, including humans. Herein we report a novel mART from P. luminescens called Photox. This 46-kDa toxin shows high homology to other actin-targeting mARTs in hallmark catalytic regions and a similar core catalytic fold. Furthermore, Photox shows in vivo cytotoxic activity against yeast, with protection occurring when catalytic residues are substituted with alanine. In vitro, enzymatic activity (k(cat), 1680 +/- 75 min(-1)) is higher than that of the related iota toxin, and diminishes by nearly 14,000-fold following substitution of the catalytic Glu (E355A). This toxin specifically ADP-ribosylates monomeric alpha-skeletal actin and nonmuscle beta- and gamma-actin at Arg(177), inhibiting regular polymerization of actin filaments. These results indicate that Photox is indeed an ADP-ribosyltransferase, making it the newest member of the actin-targeting mART family.
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Affiliation(s)
- Danielle D Visschedyk
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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Ibarra JA, Steele-Mortimer O. Salmonella--the ultimate insider. Salmonella virulence factors that modulate intracellular survival. Cell Microbiol 2009; 11:1579-86. [PMID: 19775254 PMCID: PMC2774479 DOI: 10.1111/j.1462-5822.2009.01368.x] [Citation(s) in RCA: 211] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Salmonella enterica serovar Typhimurium is a common facultative intracellular pathogen that causes food-borne gastroenteritis in millions of people worldwide. Intracellular survival and replication are important virulence determinants and the bacteria can be found in a variety of phagocytic and non-phagocytic cells in vivo. Invasion of host cells and intracellular survival are dependent on two type III secretion systems, T3SS1 and T3SS2, each of which translocates a distinct set of effector proteins. However, other virulence factors including ion transporters, superoxide dismutase, flagella and fimbriae are also involved in accessing and utilizing the intracellular niche.
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Affiliation(s)
- J Antonio Ibarra
- Laboratory of Intracellular Parasites, NIAID, NIH, Rocky Mountain Laboratories, Hamilton, MT, USA
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Shi L, Ansong C, Smallwood H, Rommereim L, McDermott JE, Brewer HM, Norbeck AD, Taylor RC, Gustin JK, Heffron F, Smith RD, Adkins JN. Proteome of Salmonella Enterica Serotype Typhimurium Grown in a Low Mg/pH Medium. ACTA ACUST UNITED AC 2009; 2:388-397. [PMID: 19953200 DOI: 10.4172/jpb.1000099] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
To determine the impact of a low Mg(2+)/pH defined growth medium (MgM) on the proteome of Salmonella enterica serotype Typhimurium, we cultured S. Typhimurium cells in the medium under two different conditions termed MgM Shock and MgM Dilution and then comparatively analyzed the bacterial cells harvested from these conditions by a global proteomic approach. Proteomic results showed that MgM Shock and MgM Dilution differentially affected the S. Typhimurium proteome. MgM Shock induced a group of proteins whose induction usually occurred at low O(2) level, while MgM Dilution induced those related to the type III secretion system (T3SS) of Salmonella Pathogenicity Island 2 (SPI2) and those involved in thiamine or biotin biosynthesis. The metabolic state of the S. Typhimurium cells grown under MgM Shock condition also differed significantly from that under MgM Dilution condition. Western blot analysis not only confirmed the proteomic results, but also showed that the abundances of SPI2-T3SS proteins SsaQ and SseE and biotin biosynthesis proteins BioB and BioD increased after S. Typhimurium infection of RAW 264.7 macrophages. Deletion of the gene encoding BioB reduced the bacterial ability to replicate inside the macrophages, suggesting a biotin-limited environment encountered by S. Typhimurium within RAW 264.7 macrophages.
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Affiliation(s)
- Liang Shi
- Pacific Northwest National Laboratory, Richland, Washington 99352
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McGhie EJ, Brawn LC, Hume PJ, Humphreys D, Koronakis V. Salmonella takes control: effector-driven manipulation of the host. Curr Opin Microbiol 2009; 12:117-24. [PMID: 19157959 PMCID: PMC2647982 DOI: 10.1016/j.mib.2008.12.001] [Citation(s) in RCA: 240] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Revised: 11/27/2008] [Accepted: 12/01/2008] [Indexed: 01/20/2023]
Abstract
Salmonella pathogenesis relies upon the delivery of over thirty specialised effector proteins into the host cell via two distinct type III secretion systems. These effectors act in concert to subvert the host cell cytoskeleton, signal transduction pathways, membrane trafficking and pro-inflammatory responses. This allows Salmonella to invade non-phagocytic epithelial cells, establish and maintain an intracellular replicative niche and, in some cases, disseminate to cause systemic disease. This review focuses on the actions of the effectors on their host cell targets during each stage of Salmonella infection.
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