1
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Ilyas M, Purkait D, Atmakuri K. Genomic islands and their role in fitness traits of two key sepsis-causing bacterial pathogens. Brief Funct Genomics 2024; 23:55-68. [PMID: 36528816 DOI: 10.1093/bfgp/elac051] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 11/03/2022] [Accepted: 11/11/2022] [Indexed: 01/21/2024] Open
Abstract
To survive and establish a niche for themselves, bacteria constantly evolve. Toward that, they not only insert point mutations and promote illegitimate recombinations within their genomes but also insert pieces of 'foreign' deoxyribonucleic acid, which are commonly referred to as 'genomic islands' (GEIs). The GEIs come in several forms, structures and types, often providing a fitness advantage to the harboring bacterium. In pathogenic bacteria, some GEIs may enhance virulence, thus altering disease burden, morbidity and mortality. Hence, delineating (i) the GEIs framework, (ii) their encoded functions, (iii) the triggers that help them move, (iv) the mechanisms they exploit to move among bacteria and (v) identification of their natural reservoirs will aid in superior tackling of several bacterial diseases, including sepsis. Given the vast array of comparative genomics data, in this short review, we provide an overview of the GEIs, their types and the compositions therein, especially highlighting GEIs harbored by two important pathogens, viz. Acinetobacter baumannii and Klebsiella pneumoniae, which prominently trigger sepsis in low- and middle-income countries. Our efforts help shed some light on the challenges these pathogens pose when equipped with GEIs. We hope that this review will provoke intense research into understanding GEIs, the cues that drive their mobility across bacteria and the ways and means to prevent their transfer, especially across pathogenic bacteria.
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Affiliation(s)
- Mohd Ilyas
- Bacterial Pathogenesis Lab, Infection and Immunity Group, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana 121001, India
| | - Dyuti Purkait
- Bacterial Pathogenesis Lab, Infection and Immunity Group, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana 121001, India
| | - Krishnamohan Atmakuri
- Bacterial Pathogenesis Lab, Infection and Immunity Group, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana 121001, India
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2
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Han J, Aljahdali N, Zhao S, Tang H, Harbottle H, Hoffmann M, Frye JG, Foley SL. Infection biology of Salmonella enterica. EcoSal Plus 2024:eesp00012023. [PMID: 38415623 DOI: 10.1128/ecosalplus.esp-0001-2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 07/31/2023] [Indexed: 02/29/2024]
Abstract
Salmonella enterica is the leading cause of bacterial foodborne illness in the USA, with an estimated 95% of salmonellosis cases due to the consumption of contaminated food products. Salmonella can cause several different disease syndromes, with the most common being gastroenteritis, followed by bacteremia and typhoid fever. Among the over 2,600 currently identified serotypes/serovars, some are mostly host-restricted and host-adapted, while the majority of serotypes can infect a broader range of host species and are associated with causing both livestock and human disease. Salmonella serotypes and strains within serovars can vary considerably in the severity of disease that may result from infection, with some serovars that are more highly associated with invasive disease in humans, while others predominantly cause mild gastroenteritis. These observed clinical differences may be caused by the genetic make-up and diversity of the serovars. Salmonella virulence systems are very complex containing several virulence-associated genes with different functions that contribute to its pathogenicity. The different clinical syndromes are associated with unique groups of virulence genes, and strains often differ in the array of virulence traits they display. On the chromosome, virulence genes are often clustered in regions known as Salmonella pathogenicity islands (SPIs), which are scattered throughout different Salmonella genomes and encode factors essential for adhesion, invasion, survival, and replication within the host. Plasmids can also carry various genes that contribute to Salmonella pathogenicity. For example, strains from several serovars associated with significant human disease, including Choleraesuis, Dublin, Enteritidis, Newport, and Typhimurium, can carry virulence plasmids with genes contributing to attachment, immune system evasion, and other roles. The goal of this comprehensive review is to provide key information on the Salmonella virulence, including the contributions of genes encoded in SPIs and plasmids during Salmonella pathogenesis.
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Affiliation(s)
- Jing Han
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA
| | - Nesreen Aljahdali
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA
- Biological Science Department, College of Science, King Abdul-Aziz University, Jeddah, Saudi Arabia
| | - Shaohua Zhao
- Center for Veterinary Medicine, U.S. Food and Drug Administration, Rockville, Maryland, USA
| | - Hailin Tang
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA
| | - Heather Harbottle
- Center for Veterinary Medicine, U.S. Food and Drug Administration, Rockville, Maryland, USA
| | - Maria Hoffmann
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, College Park, Maryland, USA
| | - Jonathan G Frye
- Agricutlutral Research Service, U.S. Department of Agriculture, Athens, Georgia, USA
| | - Steven L Foley
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA
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3
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Mohammed BT. Identification and bioinformatic analysis of invA gene of Salmonella in free range chicken. BRAZ J BIOL 2024; 84:e263363. [DOI: 10.1590/1519-6984.263363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Accepted: 08/15/2022] [Indexed: 11/22/2022] Open
Abstract
Abstract Salmonella is a serious cause of the health issues in human and animal worldwide. Salmonella has been isolated from different biological samples and it considers as the key role in induction of inflammation of gastrointestinal tract which in turn cause diarrhoea in different species. To further understand the involvement of Salmonella in contaminating and infecting fresh eggs and meat of free-range chicken. This study aimed to establish the microbiological and molecular detections of Salmonella in the cloaca of the free-range chicken and to identify predicted biological functions using Kyoto Encyclopedia of Gene and Genomic (KEGG) pathways and protein-protein interaction. Cloacal swabs were collected from free range chicken raised in the local farm in Duhok city. The isolates were cultured and biochemical test performed using XLD and TSI, respectively. Molecular detection and functional annotation of invA gene was carried out using Conventional PCR and bioinformatics approaches. The present study found that Salmonella was detected in 36 out of 86 samples using microbiological methods. To confirm these findings, invA gene was utilised and 9 out of 36 Salmonella isolates have shown a positive signal of invA by agarose gel. In addition, bioinformatic analysis revealed that invA gene was mainly associated with bacterial secretion processes as well as their KEGG terms and Protein-Protein Interaction were involved in bacterial invasion and secretion pathways. These findings suggested that invA gene plays important role in regulating colonization and invasion processes of Salmonella within the gut host in the free range chicken.
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4
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Zhou G, Zhao Y, Ma Q, Li Q, Wang S, Shi H. Manipulation of host immune defenses by effector proteins delivered from multiple secretion systems of Salmonella and its application in vaccine research. Front Immunol 2023; 14:1152017. [PMID: 37081875 PMCID: PMC10112668 DOI: 10.3389/fimmu.2023.1152017] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 03/23/2023] [Indexed: 04/07/2023] Open
Abstract
Salmonella is an important zoonotic bacterial species and hazardous for the health of human beings and livestock globally. Depending on the host, Salmonella can cause diseases ranging from gastroenteritis to life-threatening systemic infection. In this review, we discuss the effector proteins used by Salmonella to evade or manipulate four different levels of host immune defenses: commensal flora, intestinal epithelial-mucosal barrier, innate and adaptive immunity. At present, Salmonella has evolved a variety of strategies against host defense mechanisms, among which various effector proteins delivered by the secretory systems play a key role. During its passage through the digestive system, Salmonella has to face the intact intestinal epithelial barrier as well as competition with commensal flora. After invasion of host cells, Salmonella manipulates inflammatory pathways, ubiquitination and autophagy processes with the help of effector proteins. Finally, Salmonella evades the adaptive immune system by interfering the migration of dendritic cells and interacting with T and B lymphocytes. In conclusion, Salmonella can manipulate multiple aspects of host defense to promote its replication in the host.
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Affiliation(s)
- Guodong Zhou
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
- Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Yuying Zhao
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
- Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Qifeng Ma
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
- Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Quan Li
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
- Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Shifeng Wang
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Huoying Shi
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
- Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou University (JIRLAAPS), Yangzhou, China
- *Correspondence: Huoying Shi,
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5
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Synthesis of resveratrol derivatives and their anti-virulence activity as T3SS inhibitors of Salmonella. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.134826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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6
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Shikov AE, Belousova ME, Belousov MV, Nizhnikov AA, Antonets KS. Salmonella-Based Biorodenticides: Past Applications and Current Contradictions. Int J Mol Sci 2022; 23:ijms232314595. [PMID: 36498920 PMCID: PMC9736839 DOI: 10.3390/ijms232314595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/03/2022] [Accepted: 11/14/2022] [Indexed: 11/24/2022] Open
Abstract
The idea of using pathogens to control pests has existed since the end of the 19th century. Enterobacteria from the genus Salmonella, discovered at that time, are the causative agents of many serious diseases in mammals often leading to death. Mostly, the strains of Salmonella are able to infect a wide spectrum of hosts belonging to vertebrates, but some of them show host restriction. Several strains of these bacteria have been used as biorodenticides due to the host restriction until they were banned in many countries in the second part of the 20th century. The main reason for the ban was their potential pathogenicity for some domestic animals and poultry and the outbreaks of gastroenteritis in humans. Since that time, a lot of data regarding the host specificity and host restriction of different strains of Salmonella have been accumulated, and the complexity of the molecular mechanisms affecting it has been uncovered. In this review, we summarize the data regarding the history of studying and application of Salmonella-based rodenticides, discuss molecular systems controlling the specificity of Salmonella interactions within its multicellular hosts at different stages of infection, and attempt to reconstruct the network of genes and their allelic variants which might affect the host-restriction mechanisms.
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Affiliation(s)
- Anton E. Shikov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), Pushkin, St. Petersburg 196608, Russia
- Faculty of Biology, St. Petersburg State University, St. Petersburg 199034, Russia
| | - Maria E. Belousova
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), Pushkin, St. Petersburg 196608, Russia
| | - Mikhail V. Belousov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), Pushkin, St. Petersburg 196608, Russia
- Faculty of Biology, St. Petersburg State University, St. Petersburg 199034, Russia
| | - Anton A. Nizhnikov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), Pushkin, St. Petersburg 196608, Russia
- Faculty of Biology, St. Petersburg State University, St. Petersburg 199034, Russia
| | - Kirill S. Antonets
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), Pushkin, St. Petersburg 196608, Russia
- Faculty of Biology, St. Petersburg State University, St. Petersburg 199034, Russia
- Correspondence:
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7
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Devlin JR, Santus W, Mendez J, Peng W, Yu A, Wang J, Alejandro-Navarreto X, Kiernan K, Singh M, Jiang P, Mechref Y, Behnsen J. Salmonella enterica serovar Typhimurium chitinases modulate the intestinal glycome and promote small intestinal invasion. PLoS Pathog 2022; 18:e1010167. [PMID: 35482787 PMCID: PMC9049507 DOI: 10.1371/journal.ppat.1010167] [Citation(s) in RCA: 5] [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: 12/03/2021] [Accepted: 03/23/2022] [Indexed: 11/19/2022] Open
Abstract
Salmonella enterica serovar Typhimurium (S. Typhimurium) is one of the leading causes of food-borne illnesses worldwide. To colonize the gastrointestinal tract, S. Typhimurium produces multiple virulence factors that facilitate cellular invasion. Chitinases have been recently emerging as virulence factors for various pathogenic bacterial species, and the S. Typhimurium genome contains two annotated chitinases: STM0018 (chiA) and STM0233. However, the role of these chitinases during S. Typhimurium pathogenesis is unknown. The putative chitinase STM0233 has not been studied previously, and only limited data exists on ChiA. Chitinases typically hydrolyze chitin polymers, which are absent in vertebrates. However, chiA expression was detected in infection models and purified ChiA cleaved carbohydrate subunits present on mammalian surface glycoproteins, indicating a role during pathogenesis. Here, we demonstrate that expression of chiA and STM0233 is upregulated in the mouse gut and that both chitinases facilitate epithelial cell adhesion and invasion. S. Typhimurium lacking both chitinases showed a 70% reduction in invasion of small intestinal epithelial cells in vitro. In a gastroenteritis mouse model, chitinase-deficient S. Typhimurium strains were also significantly attenuated in the invasion of small intestinal tissue. This reduced invasion resulted in significantly delayed S. Typhimurium dissemination to the spleen and the liver, but chitinases were not required for systemic survival. The invasion defect of the chitinase-deficient strain was rescued by the presence of wild-type S. Typhimurium, suggesting that chitinases are secreted. By analyzing N-linked glycans of small intestinal cells, we identified specific N-acetylglucosamine-containing glycans as potential extracellular targets of S. Typhimurium chitinases. This analysis also revealed a differential abundance of Lewis X/A-containing glycans that is likely a result of host cell modulation due to the detection of S. Typhimurium chitinases. Similar glycomic changes elicited by chitinase deficient strains indicate functional redundancy of the chitinases. Overall, our results demonstrate that S. Typhimurium chitinases contribute to intestinal adhesion and invasion through modulation of the host glycome.
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Affiliation(s)
- Jason R. Devlin
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, Illinois, United States of America
| | - William Santus
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, Illinois, United States of America
| | - Jorge Mendez
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, Illinois, United States of America
| | - Wenjing Peng
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, United States of America
| | - Aiying Yu
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, United States of America
| | - Junyao Wang
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, United States of America
| | - Xiomarie Alejandro-Navarreto
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, Illinois, United States of America
| | - Kaitlyn Kiernan
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, Illinois, United States of America
| | - Manmeet Singh
- Department of Pathology, University of Illinois Chicago, Chicago, Illinois, United States of America
| | - Peilin Jiang
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, United States of America
| | - Yehia Mechref
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, United States of America
| | - Judith Behnsen
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, Illinois, United States of America
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8
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Wang Y, Hou M, Kan Z, Zhang G, Li Y, Zhou L, Wang C. Identification of Novel Type Three Secretion System (T3SS) Inhibitors by Computational Methods and Anti- Salmonella Evaluations. Front Pharmacol 2021; 12:764191. [PMID: 34867388 PMCID: PMC8635108 DOI: 10.3389/fphar.2021.764191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 11/01/2021] [Indexed: 11/13/2022] Open
Abstract
Three type III secretion system (T3SS) inhibitors (compounds 5, 19, and 32) were identified by virtual screening and biological evaluation. These three compounds were evaluated against a panel of Salmonella species strains including S. enteritidis, S. typhi, S. typhimurium, S. paratyphi, and S. abortus equi, and their minimum inhibitory concentrations ranged from 1 to 53 μg/ml. Especially, these compounds showed comparable activity as the of the positive control gatifloxacin towards S. abortus equi. The present results suggest that these new T3SS inhibitors could be used as a potential lead molecule for drug development of anti-Salmonella.
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Affiliation(s)
- Yonghui Wang
- College of Agronomy, Liaocheng University, Liaocheng, China
| | - Meihui Hou
- Burns and Plastic Surgery Department, The 960th Hospital of the PLA Joint Logistics Support Force, Jinan, China
| | - Zhaodong Kan
- Laizhou City Laiyu Chemical Co., Ltd., Laizhou, China
| | | | - Yunxia Li
- Laizhou City Laiyu Chemical Co., Ltd., Laizhou, China
| | - Lei Zhou
- School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Changfa Wang
- College of Agronomy, Liaocheng University, Liaocheng, China
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9
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Cryo-EM structure of the needle filament tip complex of the Salmonella type III secretion injectisome. Proc Natl Acad Sci U S A 2021; 118:2114552118. [PMID: 34706941 DOI: 10.1073/pnas.2114552118] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2021] [Indexed: 11/18/2022] Open
Abstract
Type III secretion systems are multiprotein molecular machines required for the virulence of several important bacterial pathogens. The central element of these machines is the injectisome, a ∼5-Md multiprotein structure that mediates the delivery of bacterially encoded proteins into eukaryotic target cells. The injectisome is composed of a cytoplasmic sorting platform, and a membrane-embedded needle complex, which is made up of a multiring base and a needle-like filament that extends several nanometers from the bacterial surface. The needle filament is capped at its distal end by another substructure known as the tip complex, which is crucial for the translocation of effector proteins through the eukaryotic cell plasma membrane. Here we report the cryo-EM structure of the Salmonella Typhimurium needle tip complex docked onto the needle filament tip. Combined with a detailed analysis of structurally guided mutants, this study provides major insight into the assembly and function of this essential component of the type III secretion protein injection machine.
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10
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The type 3 secretion system requires actin polymerization to open translocon pores. PLoS Pathog 2021; 17:e1009932. [PMID: 34499700 PMCID: PMC8454972 DOI: 10.1371/journal.ppat.1009932] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 09/21/2021] [Accepted: 08/31/2021] [Indexed: 11/19/2022] Open
Abstract
Many bacterial pathogens require a type 3 secretion system (T3SS) to establish a niche. Host contact activates bacterial T3SS assembly of a translocon pore in the host plasma membrane. Following pore formation, the T3SS docks onto the translocon pore. Docking establishes a continuous passage that enables the translocation of virulence proteins, effectors, into the host cytosol. Here we investigate the contribution of actin polymerization to T3SS-mediated translocation. Using the T3SS model organism Shigella flexneri, we show that actin polymerization is required for assembling the translocon pore in an open conformation, thereby enabling effector translocation. Opening of the pore channel is associated with a conformational change to the pore, which is dependent upon actin polymerization and a coiled-coil domain in the pore protein IpaC. Analysis of an IpaC mutant that is defective in ruffle formation shows that actin polymerization-dependent pore opening is distinct from the previously described actin polymerization-dependent ruffles that are required for bacterial internalization. Moreover, actin polymerization is not required for other pore functions, including docking or pore protein insertion into the plasma membrane. Thus, activation of the T3SS is a multilayered process in which host signals are sensed by the translocon pore leading to the activation of effector translocation.
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11
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Fattinger SA, Sellin ME, Hardt WD. Salmonella effector driven invasion of the gut epithelium: breaking in and setting the house on fire. Curr Opin Microbiol 2021; 64:9-18. [PMID: 34492596 DOI: 10.1016/j.mib.2021.08.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 08/10/2021] [Accepted: 08/17/2021] [Indexed: 12/15/2022]
Abstract
Salmonella Typhimurium (S.Tm) is a major cause of diarrheal disease. The invasion into intestinal epithelial cells (IECs) is a central step in the infection cycle. It is associated with gut inflammation and thought to benefit S.Tm proliferation also in the intestinal lumen. Importantly, it is still not entirely clear how inflammation is elicited and to which extent it links to IEC invasion efficiency in vivo. In this review, we summarize recent findings explaining IEC invasion by type-three-secretion-system-1 (TTSS-1) effector proteins and discuss their effects on invasion and gut inflammation. In non-polarized tissue culture cells, the TTSS-1 effectors (mainly SopB/E/E2) elicit large membrane ruffles fueling cooperative invasion, and can directly trigger pro-inflammatory signaling. By contrast, in the murine gut, we observe discreet-invasion (mainly via the TTSS-1 effector SipA) and a prominent pro-inflammatory role of the host?"s epithelial inflammasome(s), which sense pathogen associated molecular patterns (PAMPs). We discuss why it has remained a major challenge to tease apart direct and indirect inflammatory effects of TTSS-1 effectors and explain why further research will be needed to fully determine their inflammation-modulating role(s).
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Affiliation(s)
- Stefan A Fattinger
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland; Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
| | - Mikael E Sellin
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
| | - Wolf-Dietrich Hardt
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland.
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12
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Hussain S, Ouyang P, Zhu Y, Khalique A, He C, Liang X, Shu G, Yin L. Type 3 secretion system 1 of Salmonella typhimurium and its inhibitors: a novel strategy to combat salmonellosis. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:34154-34166. [PMID: 33966165 DOI: 10.1007/s11356-021-13986-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 04/13/2021] [Indexed: 06/12/2023]
Abstract
Unsuccessful vaccination against Salmonella due to a large number of serovars, and antibiotic resistance, necessitates the development of novel therapeutics to treat salmonellosis. The development of anti-virulence agents against multi-drug-resistant bacteria is a novel strategy because of its non-bacterial feature. Hence, a thorough study of the type three secretion system (T3SS) of Salmonella would help us better understand its role in bacterial pathogenesis and development of anti-virulence agents. However, T3SS can be inhibited by different chemicals at different stages of infection and sequenced delivery of effectors can be blocked to restrict the progression of disease. This review highlights the role of T3SS-1 in the internalization, survival, and replication of Salmonella within the intestinal epithelium and T3SS inhibitors. We concluded that the better we understand the structures and functions of T3SS, the more we have chances to develop anti-virulence agents. Furthermore, greater insights into the T3SS inhibitors of Salmonella would help in the mitigation of the antibiotic resistance problem and would lead us to the era of new therapeutics against salmonellosis.
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Affiliation(s)
- Sajjad Hussain
- College of Veterinary Medicine, Sichuan Agriculture University, Huimin Road 211, Wenjiang, Chengdu, China
| | - Ping Ouyang
- College of Veterinary Medicine, Sichuan Agriculture University, Huimin Road 211, Wenjiang, Chengdu, China
| | - Yingkun Zhu
- College of Veterinary Medicine, Sichuan Agriculture University, Huimin Road 211, Wenjiang, Chengdu, China
| | - Abdul Khalique
- College of Veterinary Medicine, Sichuan Agriculture University, Huimin Road 211, Wenjiang, Chengdu, China
| | - Changliang He
- College of Veterinary Medicine, Sichuan Agriculture University, Huimin Road 211, Wenjiang, Chengdu, China
| | - Xiaoxia Liang
- College of Veterinary Medicine, Sichuan Agriculture University, Huimin Road 211, Wenjiang, Chengdu, China
| | - Gang Shu
- College of Veterinary Medicine, Sichuan Agriculture University, Huimin Road 211, Wenjiang, Chengdu, China
| | - Lizi Yin
- College of Veterinary Medicine, Sichuan Agriculture University, Huimin Road 211, Wenjiang, Chengdu, China.
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13
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Analysis of In Vivo Transcriptome of Intracellular Bacterial Pathogen Salmonella enterica serovar Typhmurium Isolated from Mouse Spleen. Pathogens 2021; 10:pathogens10070823. [PMID: 34209260 PMCID: PMC8308634 DOI: 10.3390/pathogens10070823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 06/28/2021] [Accepted: 06/28/2021] [Indexed: 11/16/2022] Open
Abstract
Salmonella enterica serovar Typhimurium (S. Typhimurium) is an important intracellular pathogen that poses a health threat to humans. This study tries to clarify the mechanism of Salmonella survival and reproduction in the host. In this study, high-throughput sequencing analysis was performed on RNA extracted from the strains isolated from infected mouse spleens and an S. Typhimurium reference strain (ATCC 14028) based on the BGISEQ-500 platform. A total of 1340 significant differentially expressed genes (DEGs) were screened. Functional annotation revealed DEGs associated with regulation, metabolism, transport and binding, pathogenesis, and motility. Through data mining and literature retrieval, 26 of the 58 upregulated DEGs (FPKM > 10) were not reported to be related to the adaptation to intracellular survival and were classified as candidate key genes (CKGs) for survival and proliferation in vivo. Our data contribute to our understanding of the mechanisms used by Salmonella to regulate virulence gene expression whilst replicating inside mammalian cells.
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14
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Hajra D, Nair AV, Chakravortty D. An elegant nano-injection machinery for sabotaging the host: Role of Type III secretion system in virulence of different human and animal pathogenic bacteria. Phys Life Rev 2021; 38:25-54. [PMID: 34090822 DOI: 10.1016/j.plrev.2021.05.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Accepted: 05/23/2021] [Indexed: 01/22/2023]
Abstract
Various Gram-negative bacteria possess a specialized membrane-bound protein secretion system known as the Type III secretion system (T3SS), which transports the bacterial effector proteins into the host cytosol thereby helping in bacterial pathogenesis. The T3SS has a special needle-like translocon that can sense the contact with the host cell membrane and translocate effectors. The export apparatus of T3SS recognizes these effector proteins bound to chaperones and translocates them into the host cell. Once in the host cell cytoplasm, these effector proteins result in modulation of the host system and promote bacterial localization and infection. Using molecular biology, bioinformatics, genetic techniques, electron microscopic studies, and mathematical modeling, the structure and function of the T3SS and the corresponding effector proteins in various bacteria have been studied. The strategies used by different human pathogenic bacteria to modulate the host system and thereby enhance their virulence mechanism using T3SS have also been well studied. Here we review the history, evolution, and general structure of the T3SS, highlighting the details of its comparison with the flagellar export machinery. Also, this article provides mechanistic details about the common role of T3SS in subversion and manipulation of host cellular processes. Additionally, this review describes specific T3SS apparatus and the role of their specific effectors in bacterial pathogenesis by considering several human and animal pathogenic bacteria.
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Affiliation(s)
- Dipasree Hajra
- Department of Microbiology & Cell Biology, Indian Institute of Science, India
| | - Abhilash Vijay Nair
- Department of Microbiology & Cell Biology, Indian Institute of Science, India
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High-Definition DIC Imaging Uncovers Transient Stages of Pathogen Infection Cycles on the Surface of Human Adult Stem Cell-Derived Intestinal Epithelium. mBio 2021; 13:e0002222. [PMID: 35100876 PMCID: PMC8805028 DOI: 10.1128/mbio.00022-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Interactions between individual pathogenic microbes and host tissues involve fast and dynamic processes that ultimately impact the outcome of infection. Using live-cell microscopy, these dynamics can be visualized to study, e.g., microbe motility, binding and invasion of host cells, and intrahost-cell survival. Such methodology typically employs confocal imaging of fluorescent tags in tumor-derived cell line infections on glass. This allows high-definition imaging but poorly reflects the host tissue's physiological architecture and may result in artifacts. We developed a method for live-cell imaging of microbial infection dynamics on human adult stem cell-derived intestinal epithelial cell (IEC) layers. These IEC layers are grown in apical imaging chambers, optimized for physiological cell arrangement and fast, but gentle, differential interference contrast (DIC) imaging. This allows subsecond visualization of both microbial and epithelial surface ultrastructure at high resolution without using fluorescent reporters. We employed this technology to probe the behavior of two model pathogens, Salmonella enterica serovar Typhimurium and Giardia intestinalis, at the intestinal epithelial surface. Our results reveal pathogen-specific swimming patterns on the epithelium and show that Salmonella lingers on the IEC surface for prolonged periods before host cell invasion, while Giardia uses circular swimming with intermittent attachments to scout for stable adhesion sites. The method even permits tracking of individual Giardia flagella, demonstrating that active flagellar beating and attachment to the IEC surface are not mutually exclusive. This work describes a generalizable and relatively inexpensive approach to resolving dynamic pathogen-IEC layer interactions, applicable even to genetically nontractable microorganisms. IMPORTANCE Knowledge of dynamic niche-specific interactions between single microbes and host cells is essential to understand infectious disease progression. However, advances in this field have been hampered by the inherent conflict between the technical requirements for high-resolution live-cell imaging on the one hand and conditions that best mimic physiological infection niche parameters on the other. Toward bridging this divide, we present a methodology for differential interference contrast (DIC) imaging of pathogen interactions at the apical surface of enteroid-derived intestinal epithelia, providing both high spatial and temporal resolution. This alleviates the need for fluorescent reporters in live-cell imaging and provides dynamic information about microbe interactions with a nontransformed, confluent, polarized, and microvilliated human gut epithelium. Using this methodology, we uncover previously unrecognized stages of Salmonella and Giardia infection cycles at the epithelial surface.
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16
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Birhanu BT, Lee EB, Lee SJ, Park SC. Targeting Salmonella Typhimurium Invasion and Intracellular Survival Using Pyrogallol. Front Microbiol 2021; 12:631426. [PMID: 33603727 PMCID: PMC7884331 DOI: 10.3389/fmicb.2021.631426] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 01/07/2021] [Indexed: 01/25/2023] Open
Abstract
Salmonella enterica serovar Typhimurium, an intracellular pathogen, evades the host immune response mechanisms to cause gastroenteritis in animals and humans. After invading the host cells, the bacteria proliferate in Salmonella-containing vacuole (SCV) and escapes from antimicrobial therapy. Moreover, Salmonella Typhimurium develops resistance to various antimicrobials including, fluoroquinolones. Treating intracellular bacteria and combating drug resistance is essential to limit the infection rate. One way of overcoming these challenges is through combination therapy. In this study, Pyrogallol (PG), a polyphenol, is combined with marbofloxacin (MAR) to investigate its effect on Salmonella Typhimurium invasion and intracellular survival inhibition. The Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of PG against Salmonella Typhimurium were 128 and 256 μg/mL, respectively. The lowest fractional inhibitory concentration (FIC) index for a combination of PG and MAR was 0.5. The gentamycin protection assay revealed that PG (30 μg/mL) alone and in combination with sub-MIC of MAR inhibited 72.75 and 76.18% of the invading bacteria in Caco-2 cells, respectively. Besides, the intracellular survival of Salmonella Typhimurium was reduced by 7.69 and 74.36% in treatment with PG alone and combined with sub-MIC of MAR, respectively, which was visualized by the confocal microscopy. PG has also shown to increase the intracellular accumulation of fluoroquinolone by 15.2 and 34.9% at 30 and 100 μg/mL concentration, respectively. Quantitative real-time PCR demonstrated PG suppressed the genetic expression of hilA, invF, sipB, and acrA by 14.6, 15.4, 13.6, and 36%, respectively. However, the downregulation of hilA, invF, sipB, and acrA increased to 80, 74.6, 78, and 70.1%, in combination with sub-MIC of MAR, respectively. Similarly, PG combined with MAR inhibited the expression of sdiA, srgE, and rck genes by 78.6, 62.8, and 61.8%, respectively. In conclusion, PG has shown antimicrobial activity against Salmonella Typhimurium alone and in combination with MAR. It also inhibited invasion and intracellular survival of the bacteria through downregulation of quorum sensing, invading virulence, and efflux pump genes. Hence, PG could be a potential antimicrobial candidate which could limit the intracellular survival and replication of Salmonella Typhimurium.
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Affiliation(s)
- Biruk Tesfaye Birhanu
- Laboratory of Veterinary Pharmacokinetics and Pharmacodynamics, College of Veterinary Medicine, Kyungpook National University, Daegu, South Korea
| | - Eon-Bee Lee
- Laboratory of Veterinary Pharmacokinetics and Pharmacodynamics, College of Veterinary Medicine, Kyungpook National University, Daegu, South Korea
| | - Seung-Jin Lee
- Development and Reproductive Toxicology Research Group, Korea Institute of Toxicology, Daejeon, South Korea
| | - Seung-Chun Park
- Laboratory of Veterinary Pharmacokinetics and Pharmacodynamics, College of Veterinary Medicine, Kyungpook National University, Daegu, South Korea
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17
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Zhong Q, Kobe B, Kappler U. Molybdenum Enzymes and How They Support Virulence in Pathogenic Bacteria. Front Microbiol 2020; 11:615860. [PMID: 33362753 PMCID: PMC7759655 DOI: 10.3389/fmicb.2020.615860] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 11/23/2020] [Indexed: 12/11/2022] Open
Abstract
Mononuclear molybdoenzymes are highly versatile catalysts that occur in organisms in all domains of life, where they mediate essential cellular functions such as energy generation and detoxification reactions. Molybdoenzymes are particularly abundant in bacteria, where over 50 distinct types of enzymes have been identified to date. In bacterial pathogens, all aspects of molybdoenzyme biology such as molybdate uptake, cofactor biosynthesis, and function of the enzymes themselves, have been shown to affect fitness in the host as well as virulence. Although current studies are mostly focused on a few key pathogens such as Escherichia coli, Salmonella enterica, Campylobacter jejuni, and Mycobacterium tuberculosis, some common themes for the function and adaptation of the molybdoenzymes to pathogen environmental niches are emerging. Firstly, for many of these enzymes, their role is in supporting bacterial energy generation; and the corresponding pathogen fitness and virulence defects appear to arise from a suboptimally poised metabolic network. Secondly, all substrates converted by virulence-relevant bacterial Mo enzymes belong to classes known to be generated in the host either during inflammation or as part of the host signaling network, with some enzyme groups showing adaptation to the increased conversion of such substrates. Lastly, a specific adaptation to bacterial in-host survival is an emerging link between the regulation of molybdoenzyme expression in bacterial pathogens and the presence of immune system-generated reactive oxygen species. The prevalence of molybdoenzymes in key bacterial pathogens including ESKAPE pathogens, paired with the mounting evidence of their central roles in bacterial fitness during infection, suggest that they could be important future drug targets.
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Affiliation(s)
- Qifeng Zhong
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD, Australia
| | - Bostjan Kobe
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD, Australia.,Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, Australia
| | - Ulrike Kappler
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD, Australia
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18
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Tambassi M, Berni M, Bracchi C, Scaltriti E, Morganti M, Bolzoni L, Tanner JR, Thilliez G, Kingsley RA, Pongolini S, Casadei G. Mutation of hilD in a Salmonella Derby lineage linked to swine adaptation and reduced risk to human health. Sci Rep 2020; 10:21539. [PMID: 33299016 PMCID: PMC7726570 DOI: 10.1038/s41598-020-78443-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 11/18/2020] [Indexed: 12/11/2022] Open
Abstract
AbstractSalmonella enterica variants exhibit diverse host adaptation, outcome of infection, and associated risk to food safety. Analysis of the distribution of Salmonella enterica serovar Derby (S. Derby) subtypes in human and swine identified isolates with a distinct PFGE profile that were significantly under-represented in human infections, consistent with further host adaptation to swine. Here we show that isolates with this PFGE profile form a distinct phylogenetic sub-clade within S. Derby and exhibit a profound reduction in invasion of human epithelial cells, and a relatively small reduction in swine epithelial cells. A single missense mutation in hilD, that encodes the master-regulator of the Salmonella Pathogenicity Island 1 (SPI-1), was present in the adapted lineage. The missense mutation resulted in a loss of function of HilD that accounted for reduced invasion in human epithelial cells. The relatively small impact of the mutation on interaction with swine cells was consistent with an alternative mechanism of invasion in this pathogen-host combination.
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19
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Bao H, Wang S, Zhao JH, Liu SL. Salmonella secretion systems: Differential roles in pathogen-host interactions. Microbiol Res 2020; 241:126591. [PMID: 32932132 DOI: 10.1016/j.micres.2020.126591] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 08/24/2020] [Accepted: 08/29/2020] [Indexed: 12/26/2022]
Abstract
The bacterial genus Salmonella includes a large group of food-borne pathogens that cause a variety of gastrointestinal or systemic diseases in hosts. Salmonella use several secretion devices to inject various effectors targeting eukaryotic hosts, or bacteria. In the past few years, considerable progress has been made towards understanding the structural features and molecular mechanisms of the secretion systems of Salmonella, particularly regarding their roles in host-pathogen interactions. In this review, we summarize the current advances about the main characteristics of the Salmonella secretion systems. Clarifying the roles of the secretion systems in the process of infecting various hosts will broaden our understanding of the importance of microbial interactions in maintaining human health and will provide information for developing novel therapeutic approaches.
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Affiliation(s)
- Hongxia Bao
- Genomics Research Center, College of Pharmacy, Harbin Medical University, Harbin, China; HMU-UCCSM Centre for Infection and Genomics, Harbin Medical University, Harbin, China; Translational Medicine Research and Cooperation Center of Northern China, Heilongjiang Academy of Medical Sciences, Harbin, China.
| | - Shuang Wang
- Department of Biopharmaceutical Sciences (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), College of Pharmacy, Harbin Medical University, Harbin, China
| | - Jian-Hua Zhao
- Genomics Research Center, College of Pharmacy, Harbin Medical University, Harbin, China; HMU-UCCSM Centre for Infection and Genomics, Harbin Medical University, Harbin, China; Translational Medicine Research and Cooperation Center of Northern China, Heilongjiang Academy of Medical Sciences, Harbin, China
| | - Shu-Lin Liu
- Genomics Research Center, College of Pharmacy, Harbin Medical University, Harbin, China; HMU-UCCSM Centre for Infection and Genomics, Harbin Medical University, Harbin, China; Translational Medicine Research and Cooperation Center of Northern China, Heilongjiang Academy of Medical Sciences, Harbin, China; Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Canada.
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20
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Furter M, Sellin ME, Hansson GC, Hardt WD. Mucus Architecture and Near-Surface Swimming Affect Distinct Salmonella Typhimurium Infection Patterns along the Murine Intestinal Tract. Cell Rep 2020; 27:2665-2678.e3. [PMID: 31141690 PMCID: PMC6547020 DOI: 10.1016/j.celrep.2019.04.106] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 04/01/2019] [Accepted: 04/24/2019] [Indexed: 12/22/2022] Open
Abstract
Mucus separates gut-luminal microbes from the tissue. It is unclear how pathogens like Salmonella Typhimurium (S.Tm) can overcome this obstacle. Using live microscopy, we monitored S.Tm interactions with native murine gut explants and studied how mucus affects the infection. A dense inner mucus layer covers the distal colon tissue, limiting direct tissue access. S.Tm performs near-surface swimming on this mucus layer, which allows probing for colon mucus heterogeneities, but can also entrap the bacterium in the dense inner colon mucus layer. In the cecum, dense mucus fills only the bottom of the intestinal crypts, leaving the epithelium between crypts unshielded and prone to access by motile and non-motile bacteria alike. This explains why the cecum is highly infection permissive and represents the primary site of S.Tm enterocolitis in the streptomycin mouse model. Our findings highlight the importance of mucus in intestinal defense and homeostasis. Live imaging of Salmonella near-surface swimming on mouse colon inner mucus layer Colon inner mucus layer traversal requires mucus breaches and flagellar propulsion The mouse cecum lacks a continuous mucus layer, leaving epithelium tips uncovered Exposed cecum epithelium tips are a hotspot for Salmonella infection
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Affiliation(s)
- Markus Furter
- Institute for Microbiology, ETH Zürich, 8093 Zürich, Switzerland
| | - Mikael E Sellin
- Institute for Microbiology, ETH Zürich, 8093 Zürich, Switzerland
| | - Gunnar C Hansson
- Department of Medical Biochemistry, University of Gothenburg, 40530 Gothenburg, Sweden
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21
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Verma S, Prescott RA, Ingano L, Nickerson KP, Hill E, Faherty CS, Fasano A, Senger S, Cherayil BJ. The YrbE phospholipid transporter of Salmonella enterica serovar Typhi regulates the expression of flagellin and influences motility, adhesion and induction of epithelial inflammatory responses. Gut Microbes 2020; 11:526-538. [PMID: 31829769 PMCID: PMC7527071 DOI: 10.1080/19490976.2019.1697593] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
serovar Typhi is the etiologic agent of typhoid fever, a major public health problem in the developing world. Moving toward and adhering to the intestinal epithelium represents key initial steps of infection by S. Typhi. We examined the role of the S. Typhi yrbE gene, which encodes an inner membrane phospholipid transporter, in these interactions with epithelial cells. Disruption of yrbE resulted in elevated expression of flagellin and a hypermotile phenotype. It also significantly reduced the ability of S. Typhi to adhere to the HeLa epithelial cell line and to polarized primary epithelial cells derived from human ileal organoids. Interestingly, the yrbE-deficient strain of S. Typhi induced higher production of interleukin-8 from the primary human ileal epithelial cell monolayers compared to the wild-type bacteria. Deletion of the flagellin gene (fliC) in the yrbE-deficient S. Typhi inhibited motility and attenuated interleukin-8 production, but it did not correct the defect in adhesion. We also disrupted yrbE in S. Typhimurium. In contrast to the results in S. Typhi, the deficiency of yrbE in S. Typhimurium had no significant effect on flagellin expression, motility or adhesion to HeLa cells. Correspondingly, the lack of yrbE also had no effect on association with the intestine or the severity of intestinal inflammation in the mouse model of S. Typhimurium infection. Thus, our results point to an important and serovar-specific role played by yrbE in the early stages of intestinal infection by S. Typhi.
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Affiliation(s)
- Smriti Verma
- Mucosal Immunology and Biology Research Center, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, USA,Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Rachel A. Prescott
- Mucosal Immunology and Biology Research Center, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Laura Ingano
- Mucosal Immunology and Biology Research Center, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Kourtney P. Nickerson
- Mucosal Immunology and Biology Research Center, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, USA,Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Emily Hill
- Mucosal Immunology and Biology Research Center, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Christina S. Faherty
- Mucosal Immunology and Biology Research Center, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, USA,Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Alessio Fasano
- Mucosal Immunology and Biology Research Center, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, USA,Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Stefania Senger
- Mucosal Immunology and Biology Research Center, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, USA,Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Bobby J. Cherayil
- Mucosal Immunology and Biology Research Center, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, USA,Department of Pediatrics, Harvard Medical School, Boston, MA, USA,CONTACT Bobby J. Cherayil Mucosal Immunology and Biology Research Center, Department of Pediatrics, Massachusetts General Hospital, Boston, MA, USA
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22
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M Campos JC, Antunes LCM, Ferreira RBR. Global priority pathogens: virulence, antimicrobial resistance and prospective treatment options. Future Microbiol 2020; 15:649-677. [DOI: 10.2217/fmb-2019-0333] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp. and Salmonella spp. are part of a group of pathogens that pose a major threat to human health due to the emergence of multidrug-resistant strains. Moreover, these bacteria have several virulence factors that allow them to successfully colonize their hosts, such as toxins and the ability to produce biofilms, resulting in an urgent need to develop new strategies to fight these pathogens. In this review, we compile the most up-to-date information on the epidemiology, virulence and resistance of these clinically important microorganisms. Additionally, we address new therapeutic alternatives, with a focus on molecules with antivirulence activity, which are considered promising to combat multidrug-resistant bacteria.
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Affiliation(s)
- Juliana C de M Campos
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Luis CM Antunes
- Escola Nacional de Saúde Pública Sergio Arouca, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia de Inovação em Doenças de Populações Negligenciadas, Centro de Desenvolvimento Tecnológico em Saúde, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Rosana BR Ferreira
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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23
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Azimi T, Zamirnasta M, Sani MA, Soltan Dallal MM, Nasser A. Molecular Mechanisms of Salmonella Effector Proteins: A Comprehensive Review. Infect Drug Resist 2020; 13:11-26. [PMID: 32021316 PMCID: PMC6954085 DOI: 10.2147/idr.s230604] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 12/20/2019] [Indexed: 12/27/2022] Open
Abstract
Salmonella can be categorized into many serotypes, which are specific to known hosts or broadhosts. It makes no difference which one of the serotypes would penetrate the gastrointestinal tract because they all face similar obstacles such as mucus and microbiome. However, following their penetration, some species remain in the gastrointestinal tract; yet, others spread to another organ like gallbladder. Salmonella is required to alter the immune response to sustain its intracellular life. Changing the host response requires particular effector proteins and vehicles to translocate them. To this end, a categorized gene called Salmonella pathogenicity island (SPI) was developed; genes like Salmonella pathogenicity island encode aggressive or modulating proteins. Initially, Salmonella needs to be attached and stabilized via adhesin factor, without which no further steps can be taken. In this review, an attempt has been made to elaborate on each factor attached to the host cell or to modulating and aggressive proteins that evade immune systems. This review includes four sections: (A) attachment factors or T3SS- independent entrance, (B) effector proteins or T3SS-dependent entrance, (c) regulation of invasive genes, and (D) regulation of immune responses.
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Affiliation(s)
- Taher Azimi
- Pediatric Infections Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Students Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Zamirnasta
- Clinical Microbiology Research Center, Ilam University of Medical Science, Ilam, Iran
| | - Mahmood Alizadeh Sani
- Food Safety and Hygiene Division, Environmental health Department, School of Public Health, Tehran University of medical sciences, Tehran, Iran
- Students Research Committee, Department of Food Sciences and Technology, Faculty of Nutrition and Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Ahmad Nasser
- Clinical Microbiology Research Center, Ilam University of Medical Science, Ilam, Iran
- Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
- Department of Medical Microbiology, School of Medicine, Ilam University of Medical Science, Ilam, Iran
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24
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Functional screenings reveal different requirements for host microRNAs in Salmonella and Shigella infection. Nat Microbiol 2019; 5:192-205. [DOI: 10.1038/s41564-019-0614-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 10/18/2019] [Indexed: 12/15/2022]
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25
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Russo BC, Duncan JK, Wiscovitch AL, Hachey AC, Goldberg MB. Activation of Shigella flexneri type 3 secretion requires a host-induced conformational change to the translocon pore. PLoS Pathog 2019; 15:e1007928. [PMID: 31725799 PMCID: PMC6879154 DOI: 10.1371/journal.ppat.1007928] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 11/26/2019] [Accepted: 09/30/2019] [Indexed: 12/17/2022] Open
Abstract
Type 3 secretion systems (T3SSs) are conserved bacterial nanomachines that inject virulence proteins (effectors) into eukaryotic cells during infection. Due to their ability to inject heterologous proteins into human cells, these systems are being developed as therapeutic delivery devices. The T3SS assembles a translocon pore in the plasma membrane and then docks onto the pore. Docking activates effector secretion through the pore and into the host cytosol. Here, using Shigella flexneri, a model pathogen for the study of type 3 secretion, we determined the molecular mechanisms by which host intermediate filaments trigger docking and enable effector secretion. We show that the interaction of intermediate filaments with the translocon pore protein IpaC changed the pore's conformation in a manner that was required for docking. Intermediate filaments repositioned residues of the Shigella pore protein IpaC that are located on the surface of the pore and in the pore channel. Restricting these conformational changes blocked docking in an intermediate filament-dependent manner. These data demonstrate that a host-induced conformational change to the pore enables T3SS docking and effector secretion, providing new mechanistic insight into the regulation of type 3 secretion.
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Affiliation(s)
- Brian C. Russo
- Center for Bacterial Pathogenesis, Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jeffrey K. Duncan
- Center for Bacterial Pathogenesis, Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Alexandra L. Wiscovitch
- Center for Bacterial Pathogenesis, Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Research Scholar Initiative, The Graduate School of Arts and Sciences, Harvard University, Cambridge, Massachusetts, United States of America
| | - Austin C. Hachey
- Center for Bacterial Pathogenesis, Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Marcia B. Goldberg
- Center for Bacterial Pathogenesis, Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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26
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Zhang Y, Gu T, Chen Y, Zhu G, Vongsangnak W, Xu Q, Chen G. Screening and identification of SipC-interacting proteins in Salmonella enteritidis using Gal4 yeast two-hybrid system in duck. PeerJ 2019; 7:e7663. [PMID: 31565575 PMCID: PMC6746301 DOI: 10.7717/peerj.7663] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 08/12/2019] [Indexed: 11/29/2022] Open
Abstract
The zoonotic pathogen Salmonella not only reduces the production performance in ducks, but also poses a serious threat to human health through eggs and pollutes water bodies through feces. SipC, an effector protein of type III secretion systems (T3SS) in Salmonella, mediates translocation of effectors into the eukaryotic host. However, the precise role of SipC effectors remains unknown in ducks. In this study, the SipC from duck granulosa cells (dGCs) was selected as bait, and the SipC-interacting proteins in Salmonella enteritidis (SE) were screened using Gal4 yeast two-hybrid system in duck. Twelve SipC-interacting proteins were identified. Among those, the p53-effector related to PMP-22 (PERP) and TGF-β activated kinase 1-binding protein 2 (TAB2) were selected to further confirm the function by GST pull-down in vitro. Over-expression of PERP resulted in not only increasing SE adhesion and invasion but also triggering the production of IL-1β and IFN-α in SE infected dGCs, while knock-down PERP showed the opposite tendency (P < 0.01). In addition, TAB2 significantly induced the production of IL-6, IL-1β, IFN-α, and INF-γ in SE infected dGCs (P < 0.05), but did not cause obvious changes in SE adhesion and invasion. When the sipC in SE was deleted, the activities of duck PERP and TAB2 were abolished because they could not bind to SipC. Taken together, although the protein of PERP and TAB2 can interact with SipC, their mechanisms were different in duck challenged by SE. Therefore, PERP was involved in SE invasion and inflammatory response of dGC ovaries, and TAB2 only contributed to dGCs inflammatory response, which provided critical insights about the mechanism in host- bacterium protein interactions during Salmonella invasion in duck.
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Affiliation(s)
- Yu Zhang
- Joint International Research Laboratory of Agriculture & Agri-Product Safety of Ministry of Education, Yangzhou University, Yangzhou, China.,Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, China
| | - Tiantian Gu
- Joint International Research Laboratory of Agriculture & Agri-Product Safety of Ministry of Education, Yangzhou University, Yangzhou, China
| | - Yang Chen
- Joint International Research Laboratory of Agriculture & Agri-Product Safety of Ministry of Education, Yangzhou University, Yangzhou, China
| | - Guoqiang Zhu
- Joint International Research Laboratory of Agriculture & Agri-Product Safety of Ministry of Education, Yangzhou University, Yangzhou, China
| | - Wanwipa Vongsangnak
- Department of Zoology, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Qi Xu
- Joint International Research Laboratory of Agriculture & Agri-Product Safety of Ministry of Education, Yangzhou University, Yangzhou, China
| | - Guohong Chen
- Joint International Research Laboratory of Agriculture & Agri-Product Safety of Ministry of Education, Yangzhou University, Yangzhou, China
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27
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Dey S, Chakravarty A, Guha Biswas P, De Guzman RN. The type III secretion system needle, tip, and translocon. Protein Sci 2019; 28:1582-1593. [PMID: 31301256 DOI: 10.1002/pro.3682] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 07/05/2019] [Accepted: 07/08/2019] [Indexed: 11/06/2022]
Abstract
Many Gram-negative bacteria pathogenic to plants and animals deploy the type III secretion system (T3SS) to inject virulence factors into their hosts. All bacteria that rely on the T3SS to cause infectious diseases in humans have developed antibiotic resistance. The T3SS is an attractive target for developing new antibiotics because it is essential in virulence, and part of its structural component is exposed on the bacterial surface. The structural component of the T3SS is the needle apparatus, which is assembled from over 20 different proteins and consists of a base, an extracellular needle, a tip, and a translocon. This review summarizes the current knowledge on the structure and assembly of the needle, tip, and translocon.
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Affiliation(s)
- Supratim Dey
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas
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28
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Lou L, Zhang P, Piao R, Wang Y. Salmonella Pathogenicity Island 1 (SPI-1) and Its Complex Regulatory Network. Front Cell Infect Microbiol 2019; 9:270. [PMID: 31428589 PMCID: PMC6689963 DOI: 10.3389/fcimb.2019.00270] [Citation(s) in RCA: 153] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 07/12/2019] [Indexed: 11/30/2022] Open
Abstract
Salmonella species can infect a diverse range of birds, reptiles, and mammals, including humans. The type III protein secretion system (T3SS) encoded by Salmonella pathogenicity island 1 (SPI-1) delivers effector proteins required for intestinal invasion and the production of enteritis. The T3SS is regarded as the most important virulence factor of Salmonella. SPI-1 encodes transcription factors that regulate the expression of some virulence factors of Salmonella, while other transcription factors encoded outside SPI-1 participate in the expression of SPI-1-encoded genes. SPI-1 genes are responsible for the invasion of host cells, regulation of the host immune response, e.g., the host inflammatory response, immune cell recruitment and apoptosis, and biofilm formation. The regulatory network of SPI-1 is very complex and crucial. Here, we review the function, effectors, and regulation of SPI-1 genes and their contribution to the pathogenicity of Salmonella.
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Affiliation(s)
- Lixin Lou
- Department of Infectious Diseases, First Hospital of Jilin University, Changchun, China
| | - Peng Zhang
- Department of Infectious Diseases, First Hospital of Jilin University, Changchun, China.,Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Rongli Piao
- Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Department of Gastroenterology, First Hospital of Jilin University, Changchun, China
| | - Yang Wang
- Department of Infectious Diseases, First Hospital of Jilin University, Changchun, China.,Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
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29
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Abstract
Type III protein secretion systems (T3SSs), or injectisomes, are multiprotein nanomachines present in many Gram-negative bacteria that have a sustained long-standing close relationship with a eukaryotic host. These secretion systems have evolved to modulate host cellular functions through the activity of the effector proteins they deliver. To reach their destination, T3SS effectors must cross the multibarrier bacterial envelope and the eukaryotic cell membrane. Passage through the bacterial envelope is mediated by the needle complex, a central component of T3SSs that expands both the inner and outer membranes of Gram-negative bacteria. A set of T3SS secreted proteins, known as translocators, form a channel in the eukaryotic plasma membrane through which the effector proteins are delivered to reach the host cell cytosol. While the effector proteins are tailored to the specific lifestyle of the bacterium that encodes them, the injectisome is conserved among the different T3SSs. The central role of T3SSs in pathogenesis and their high degree of conservation make them a desirable target for the development of antimicrobial therapies against several important bacterial pathogens.
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30
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Dillon A, Lo DD. M Cells: Intelligent Engineering of Mucosal Immune Surveillance. Front Immunol 2019; 10:1499. [PMID: 31312204 PMCID: PMC6614372 DOI: 10.3389/fimmu.2019.01499] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 06/14/2019] [Indexed: 12/25/2022] Open
Abstract
M cells are specialized intestinal epithelial cells that provide the main machinery for sampling luminal microbes for mucosal immune surveillance. M cells are usually found in the epithelium overlying organized mucosal lymphoid tissues, but studies have identified multiple distinct lineages of M cells that are produced under different conditions, including intestinal inflammation. Among these lineages there is a common morphology that helps explain the efficiency of M cells in capturing luminal bacteria and viruses; in addition, M cells recruit novel cellular mechanisms to transport the particles across the mucosal barrier into the lamina propria, a process known as transcytosis. These specializations used by M cells point to a novel engineering of cellular machinery to selectively capture and transport microbial particles of interest. Because of the ability of M cells to effectively violate the mucosal barrier, the circumstances of M cell induction have important consequences. Normal immune surveillance insures that transcytosed bacteria are captured by underlying myeloid/dendritic cells; in contrast, inflammation can induce development of new M cells not accompanied by organized lymphoid tissues, resulting in bacterial transcytosis with the potential to amplify inflammatory disease. In this review, we will discuss our own perspectives on the life history of M cells and also raise a few questions regarding unique aspects of their biology among epithelia.
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Affiliation(s)
- Andrea Dillon
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, United States
| | - David D Lo
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, United States
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31
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Guo EZ, Desrosiers DC, Zalesak J, Tolchard J, Berbon M, Habenstein B, Marlovits T, Loquet A, Galán JE. A polymorphic helix of a Salmonella needle protein relays signals defining distinct steps in type III secretion. PLoS Biol 2019; 17:e3000351. [PMID: 31260457 PMCID: PMC6625726 DOI: 10.1371/journal.pbio.3000351] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 07/12/2019] [Accepted: 06/18/2019] [Indexed: 12/22/2022] Open
Abstract
Type III protein-secretion machines are essential for the interactions of many pathogenic or symbiotic bacterial species with their respective eukaryotic hosts. The core component of these machines is the injectisome, a multiprotein complex that mediates the selection of substrates, their passage through the bacterial envelope, and ultimately their delivery into eukaryotic target cells. The injectisome is composed of a large cytoplasmic complex or sorting platform, a multiring base embedded in the bacterial envelope, and a needle-like filament that protrudes several nanometers from the bacterial surface and is capped at its distal end by the tip complex. A characteristic feature of these machines is that their activity is stimulated by contact with target host cells. The sensing of target cells, thought to be mediated by the distal tip of the needle filament, generates an activating signal that must be transduced to the secretion machine by the needle filament. Here, through a multidisciplinary approach, including solid-state NMR (SSNMR) and cryo electron microscopy (cryo-EM) analyses, we have identified critical residues of the needle filament protein of a Salmonella Typhimurium type III secretion system that are involved in the regulation of the activity of the secretion machine. We found that mutations in the needle filament protein result in various specific phenotypes associated with different steps in the type III secretion process. More specifically, these studies reveal an important role for a polymorphic helix of the needle filament protein and the residues that line the lumen of its central channel in the control of type III secretion.
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Affiliation(s)
- Emily Z. Guo
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Daniel C. Desrosiers
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Jan Zalesak
- Institute of Molecular Biotechnology (IMBA), Vienna Biocenter (VBC), Vienna, Austria
| | - James Tolchard
- Institute of Chemistry and Biology of Membranes and Nano-objects, CBMN-CNRS Université de Bordeaux, Pessac, France
| | - Mélanie Berbon
- Institute of Chemistry and Biology of Membranes and Nano-objects, CBMN-CNRS Université de Bordeaux, Pessac, France
| | - Birgit Habenstein
- Institute of Chemistry and Biology of Membranes and Nano-objects, CBMN-CNRS Université de Bordeaux, Pessac, France
| | - Thomas Marlovits
- Institute of Molecular Biotechnology (IMBA), Vienna Biocenter (VBC), Vienna, Austria
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
- Center for Structural Systems Biology (CSSB), University Medical Center Hamburg-Eppendorf (UKE) and German Electron Synchrotron Centre (DESY), Hamburg, Germany
| | - Antoine Loquet
- Institute of Chemistry and Biology of Membranes and Nano-objects, CBMN-CNRS Université de Bordeaux, Pessac, France
| | - Jorge E. Galán
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, United States of America
- * E-mail:
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Topological Analysis of the Type 3 Secretion System Translocon Pore Protein IpaC following Its Native Delivery to the Plasma Membrane during Infection. mBio 2019; 10:mBio.00877-19. [PMID: 31138750 PMCID: PMC6538787 DOI: 10.1128/mbio.00877-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The type 3 secretion system (T3SS) is a nanomachine required for virulence of many bacterial pathogens that infect humans. The system delivers bacterial virulence proteins into the cytosol of human cells, where the virulence proteins promote bacterial infection. The T3SS forms a translocon pore in the membranes of target cells. This pore is the portal through which bacterial virulence proteins are delivered by the T3SS into the eukaryotic cytosol. The pore also regulates secretion of these virulence proteins. Our work defines the topology of translocon pore proteins in their native context during infection, resolves previously conflicting reports about the topology of the Shigella translocon pore protein IpaC, and provides new insights into how interactions of the pore with the T3SS likely produce signals that activate secretion of virulence proteins. Many Gram-negative bacterial pathogens require a type 3 secretion system (T3SS) to deliver effector proteins into eukaryotic cells. Contact of the tip complex of the T3SS with a target eukaryotic cell initiates secretion of the two bacterial proteins that assemble into the translocon pore in the plasma membrane. The translocon pore functions to regulate effector protein secretion and is the conduit for effector protein translocation across the plasma membrane. To generate insights into how the translocon pore regulates effector protein secretion, we defined the topology of the Shigella translocon pore protein IpaC in the plasma membrane following its native delivery by the T3SS. Using single cysteine substitution mutagenesis and site-directed labeling with a membrane-impermeant chemical probe, we mapped residues accessible from the extracellular surface of the cell. Our data support a model in which the N terminus of IpaC is extracellular and the C terminus of IpaC is intracellular. These findings resolve previously conflicting data on IpaC topology that were based on nonnative delivery of IpaC to membranes. Salmonella enterica serovar Typhimurium also requires the T3SS for effector protein delivery into eukaryotic cells. Although the sequence of IpaC is closely related to the Salmonella translocon pore protein SipC, the two proteins have unique functional attributes during infection. We showed a similar overall topology for SipC and IpaC and identified subtle topological differences between their transmembrane α-helixes and C-terminal regions. Together, our data suggest that topological differences among distinct translocon pore proteins may dictate organism-specific functional differences of the T3SSs during infection.
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33
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Nauth T, Huschka F, Schweizer M, Bosse JB, Diepold A, Failla AV, Steffen A, Stradal TEB, Wolters M, Aepfelbacher M. Visualization of translocons in Yersinia type III protein secretion machines during host cell infection. PLoS Pathog 2018; 14:e1007527. [PMID: 30586431 PMCID: PMC6324820 DOI: 10.1371/journal.ppat.1007527] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 01/08/2019] [Accepted: 12/14/2018] [Indexed: 12/13/2022] Open
Abstract
Type III secretion systems (T3SSs) are essential virulence factors of numerous bacterial pathogens. Upon host cell contact the T3SS machinery—also named injectisome—assembles a pore complex/translocon within host cell membranes that serves as an entry gate for the bacterial effectors. Whether and how translocons are physically connected to injectisome needles, whether their phenotype is related to the level of effector translocation and which target cell factors trigger their formation have remained unclear. We employed the superresolution fluorescence microscopy techniques Stimulated Emission Depletion (STED) and Structured Illumination Microscopy (SIM) as well as immunogold electron microscopy to visualize Y. enterocolitica translocons during infection of different target cell types. Thereby we were able to resolve translocon and needle complex proteins within the same injectisomes and demonstrate that these fully assembled injectisomes are generated in a prevacuole, a PI(4,5)P2 enriched host cell compartment inaccessible to large extracellular proteins like antibodies. Furthermore, the operable translocons were produced by the yersiniae to a much larger degree in macrophages (up to 25% of bacteria) than in HeLa cells (2% of bacteria). However, when the Rho GTPase Rac1 was activated in the HeLa cells, uptake of the yersiniae into the prevacuole, translocon formation and effector translocation were strongly enhanced reaching the same levels as in macrophages. Our findings indicate that operable T3SS translocons can be visualized as part of fully assembled injectisomes with superresolution fluorescence microscopy techniques. By using this technology, we provide novel information about the spatiotemporal organization of T3SS translocons and their regulation by host cell factors. Many human, animal and plant pathogenic bacteria employ a molecular machine termed injectisome to inject their toxins into host cells. Because injectisomes are crucial for these bacteria’s infectious potential they have been considered as targets for antiinfective drugs. Injectisomes are highly similar between the different bacterial pathogens and most of their overall structure is well established at the molecular level. However, only little information is available for a central part of the injectisome named the translocon. This pore-like assembly integrates into host cell membranes and thereby serves as an entry gate for the bacterial toxins. We used state of the art fluorescence microscopy to watch translocons of the diarrheagenic pathogen Yersinia enterocolitica during infection of human host cells. Thereby we could for the first time—with fluorescence microscopy—visualize translocons connected to other parts of the injectisome. Furthermore, because translocons mark functional injectisomes we could obtain evidence that injectisomes only become active for secretion of translocators when the bacteria are almost completely enclosed by host cells. These findings provide a novel view on the organization and regulation of bacterial translocons and may thus open up new strategies to block the function of infectious bacteria.
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Affiliation(s)
- Theresa Nauth
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Franziska Huschka
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Michaela Schweizer
- Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Jens B. Bosse
- Heinrich-Pette-Institute (HPI), Leibniz-Institute for Experimental Virology, Hamburg, Germany
| | - Andreas Diepold
- Department of Ecophysiology, Max-Planck-Institute for Terrestrial Microbiology, Marburg, Germany
| | - Antonio Virgilio Failla
- UKE Microscopy Imaging Facility, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Anika Steffen
- Department of Cell Biology, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - Theresia E. B. Stradal
- Department of Cell Biology, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - Manuel Wolters
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Martin Aepfelbacher
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
- * E-mail:
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34
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Tawk C, Nigro G, Rodrigues Lopes I, Aguilar C, Lisowski C, Mano M, Sansonetti P, Vogel J, Eulalio A. Stress-induced host membrane remodeling protects from infection by non-motile bacterial pathogens. EMBO J 2018; 37:embj.201798529. [PMID: 30389666 PMCID: PMC6276891 DOI: 10.15252/embj.201798529] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 10/05/2018] [Accepted: 10/10/2018] [Indexed: 01/01/2023] Open
Abstract
While mucosal inflammation is a major source of stress during enteropathogen infection, it remains to be fully elucidated how the host benefits from this environment to clear the pathogen. Here, we show that host stress induced by different stimuli mimicking inflammatory conditions strongly reduces the binding of Shigella flexneri to epithelial cells. Mechanistically, stress activates acid sphingomyelinase leading to host membrane remodeling. Consequently, knockdown or pharmacological inhibition of the acid sphingomyelinase blunts the stress-dependent inhibition of Shigella binding to host cells. Interestingly, stress caused by intracellular Shigella replication also results in remodeling of the host cell membrane, in vitro and in vivo, which precludes re-infection by this and other non-motile pathogens. In contrast, Salmonella Typhimurium overcomes the shortage of permissive entry sites by gathering effectively at the remaining platforms through its flagellar motility. Overall, our findings reveal host membrane remodeling as a novel stress-responsive cell-autonomous defense mechanism that protects epithelial cells from infection by non-motile bacterial pathogens.
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Affiliation(s)
- Caroline Tawk
- Host RNA Metabolism Group, Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany.,RNA Biology Group, Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany
| | - Giulia Nigro
- Molecular Microbial Pathogenesis Laboratory, Institut Pasteur, Paris, France
| | - Ines Rodrigues Lopes
- Functional Genomics and RNA-based Therapeutics, UC-BIOTECH, Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal.,RNA & Infection Group, UC-BIOTECH, Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal
| | - Carmen Aguilar
- Host RNA Metabolism Group, Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany
| | - Clivia Lisowski
- Host RNA Metabolism Group, Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany
| | - Miguel Mano
- Functional Genomics and RNA-based Therapeutics, UC-BIOTECH, Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal
| | - Philippe Sansonetti
- Molecular Microbial Pathogenesis Laboratory, Institut Pasteur, Paris, France
| | - Jörg Vogel
- RNA Biology Group, Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany.,Helmholtz Institute for RNA-Based Infection Research (HIRI), Würzburg, Germany
| | - Ana Eulalio
- Host RNA Metabolism Group, Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany .,RNA & Infection Group, UC-BIOTECH, Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal
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35
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Shivcharan S, Yadav J, Qadri A. Host lipid sensing promotes invasion of cells with pathogenic Salmonella. Sci Rep 2018; 8:15501. [PMID: 30341337 PMCID: PMC6195605 DOI: 10.1038/s41598-018-33319-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 09/24/2018] [Indexed: 01/09/2023] Open
Abstract
Pathogenic Salmonella species initiate infection by invading non-phagocytic intestinal epithelial cells (IEC). This invasion is brought about by a number of Salmonella invasion promoting molecules (Sips) encoded by the Salmonella Pathogenicity Island - 1 (SPI-1). Intracellular delivery of some of these molecules also brings about caspase-1 - mediated pyroptotic cell death that contributes to pathogen clearance. These molecules are secreted and delivered inside cells upon contact of Salmonella with one or more host signals whose identity has not been established. We show that lysophosphatidylcholine (LPC) released following activation of caspase-1 in Salmonella - infected cells and abundant in plasma amplifies production of Sips from this pathogen and promotes its cellular invasion. LPC brings about adenylate cyclase and cAMP receptor protein (CRP) - dependent de novo synthesis of SipC that is accompanied by its translocation to bacterial cell surface and release into the outside milieu. Treatment of Salmonella with LPC produces sustained induction of SPI - 1 transcriptional regulator, hilA. Our findings reveal a novel host lipid sensing - driven regulatory mechanism for Salmonella invasion.
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Affiliation(s)
- Sonia Shivcharan
- Hybridoma Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Jitender Yadav
- Hybridoma Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Ayub Qadri
- Hybridoma Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India.
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36
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Park D, Lara-Tejero M, Waxham MN, Li W, Hu B, Galán JE, Liu J. Visualization of the type III secretion mediated Salmonella-host cell interface using cryo-electron tomography. eLife 2018; 7:39514. [PMID: 30281019 PMCID: PMC6175578 DOI: 10.7554/elife.39514] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 09/24/2018] [Indexed: 02/01/2023] Open
Abstract
Many important gram-negative bacterial pathogens use highly sophisticated type III protein secretion systems (T3SSs) to establish complex host-pathogen interactions. Bacterial-host cell contact triggers the activation of the T3SS and the subsequent insertion of a translocon pore into the target cell membrane, which serves as a conduit for the passage of effector proteins. Therefore the initial interaction between T3SS-bearing bacteria and host cells is the critical step in the deployment of the protein secretion machine, yet this process remains poorly understood. Here, we use high-throughput cryo-electron tomography (cryo-ET) to visualize the T3SS-mediated Salmonella-host cell interface. Our analysis reveals the intact translocon at an unprecedented level of resolution, its deployment in the host cell membrane, and the establishment of an intimate association between the bacteria and the target cells, which is essential for effector translocation. Our studies provide critical data supporting the long postulated direct injection model for effector translocation.
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Affiliation(s)
- Donghyun Park
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, United States.,Microbial Sciences Institute, Yale University School of Medicine, New Haven, United States
| | - Maria Lara-Tejero
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, United States
| | - M Neal Waxham
- Department of Neurobiology and Anatomy, McGovern Medical School, The University of Texas Health Science Center at Houston, Texas, United States
| | - Wenwei Li
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, United States.,Microbial Sciences Institute, Yale University School of Medicine, New Haven, United States
| | - Bo Hu
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Texas, United States.,Department of Pathology and Laboratory Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, Texas, United States
| | - Jorge E Galán
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, United States
| | - Jun Liu
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, United States.,Microbial Sciences Institute, Yale University School of Medicine, New Haven, United States.,Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Texas, United States
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37
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Patrick KL, Wojcechowskyj JA, Bell SL, Riba MN, Jing T, Talmage S, Xu P, Cabello AL, Xu J, Shales M, Jimenez-Morales D, Ficht TA, de Figueiredo P, Samuel JE, Li P, Krogan NJ, Watson RO. Quantitative Yeast Genetic Interaction Profiling of Bacterial Effector Proteins Uncovers a Role for the Human Retromer in Salmonella Infection. Cell Syst 2018; 7:323-338.e6. [PMID: 30077634 PMCID: PMC6160342 DOI: 10.1016/j.cels.2018.06.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 05/21/2018] [Accepted: 06/21/2018] [Indexed: 11/26/2022]
Abstract
Intracellular bacterial pathogens secrete a repertoire of effector proteins into host cells that are required to hijack cellular pathways and cause disease. Despite decades of research, the molecular functions of most bacterial effectors remain unclear. To address this gap, we generated quantitative genetic interaction profiles between 36 validated and putative effectors from three evolutionarily divergent human bacterial pathogens and 4,190 yeast deletion strains. Correlating effector-generated profiles with those of yeast mutants, we recapitulated known biology for several effectors with remarkable specificity and predicted previously unknown functions for others. Biochemical and functional validation in human cells revealed a role for an uncharacterized component of the Salmonella SPI-2 translocon, SseC, in regulating maintenance of the Salmonella vacuole through interactions with components of the host retromer complex. These results exhibit the power of genetic interaction profiling to discover and dissect complex biology at the host-pathogen interface.
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Affiliation(s)
- Kristin L Patrick
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan, TX 77802, USA
| | - Jason A Wojcechowskyj
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158, USA; Quantitative Biosciences Institute (QBI), University of California, San Francisco, CA 94158, USA; J. David Gladstone Institute, San Francisco, CA 94158, USA
| | - Samantha L Bell
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan, TX 77802, USA
| | - Morgan N Riba
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan, TX 77802, USA
| | - Tao Jing
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Sara Talmage
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan, TX 77802, USA
| | - Pengbiao Xu
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Ana L Cabello
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan, TX 77802, USA; Department of Veterinary Pathobiology, Texas A&M College of Veterinary Medicine and Biomedical Sciences, College Station, TX 77843, USA; Norman Borlaug Center, Texas A&M University, College Station, TX 77843, USA
| | - Jiewei Xu
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158, USA; Quantitative Biosciences Institute (QBI), University of California, San Francisco, CA 94158, USA
| | - Michael Shales
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158, USA; Quantitative Biosciences Institute (QBI), University of California, San Francisco, CA 94158, USA
| | - David Jimenez-Morales
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158, USA; Quantitative Biosciences Institute (QBI), University of California, San Francisco, CA 94158, USA; J. David Gladstone Institute, San Francisco, CA 94158, USA
| | - Thomas A Ficht
- Department of Veterinary Pathobiology, Texas A&M College of Veterinary Medicine and Biomedical Sciences, College Station, TX 77843, USA
| | - Paul de Figueiredo
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan, TX 77802, USA; Department of Veterinary Pathobiology, Texas A&M College of Veterinary Medicine and Biomedical Sciences, College Station, TX 77843, USA; Norman Borlaug Center, Texas A&M University, College Station, TX 77843, USA
| | - James E Samuel
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan, TX 77802, USA
| | - Pingwei Li
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Nevan J Krogan
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158, USA; Quantitative Biosciences Institute (QBI), University of California, San Francisco, CA 94158, USA; J. David Gladstone Institute, San Francisco, CA 94158, USA.
| | - Robert O Watson
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan, TX 77802, USA.
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38
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Barilli E, Bacci C, StellaVilla Z, Merialdi G, D’Incau M, Brindani F, Vismarra A. Antimicrobial resistance, biofilm synthesis and virulence genes in Salmonella isolated from pigs bred on intensive farms. Ital J Food Saf 2018; 7:7223. [PMID: 30046559 PMCID: PMC6036996 DOI: 10.4081/ijfs.2018.7223] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 02/19/2018] [Accepted: 02/28/2018] [Indexed: 11/23/2022] Open
Abstract
Salmonella is the second cause of food-borne infection in humans in the USA and Europe. Pigs represent the second most important reservoir for the pathogen and the consumption of pork meat is a major risk factor for human salmonellosis. Here, we evaluated the virulence patterns of eleven Salmonella isolated from pigs (carcasses and faces) bred in intensive farms in the north of Italy. The two serotypes identified were S. Typhimurium and its monophasic variant 1,4,5,12:i:-. None of the isolates was an ESBL producer, as confirmed also by PCR. However, the presence of a multi-drug resistant pattern was evident, with all the isolates being resistant to at least to five antimicrobial agents belonging to various classes. Moreover, six out of eleven isolates showed important resistance profiles, such as resistance against colistin and ciprofloxacin, with nine to twelve recorded resistances. The isolates were negative for the biofilm synthesis test, while four different virulotypes were characterized. All the isolates showed the presence of invA, hilA, stn, ssrA, sipC. One sample also harbored ssaR and spvC genes. One strain was positive for all the virulence genes tested and was resistant to 12 antimicrobial agents. The present study contributes new data to the surveillance program for antibiotic resistance. Furthermore, the presence of eleven highly virulent isolates poses concern for human health in relation to their diffusion in the environment.
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Affiliation(s)
- Elena Barilli
- Department of Veterinary Sciences, University of Parma
| | | | | | - Giuseppe Merialdi
- Istituto Zooprofilattico Sperimentale della Lombardia, Emilia Romagna, Bologna
| | - Mario D’Incau
- Istituto Zooprofilattico Sperimentale della Lombardia, Emilia Romagna, Brescia, Italy
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39
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Schultz BM, Salazar GA, Paduro CA, Pardo-Roa C, Pizarro DP, Salazar-Echegarai FJ, Torres J, Riedel CA, Kalergis AM, Álvarez-Lobos MM, Bueno SM. Persistent Salmonella enterica serovar Typhimurium Infection Increases the Susceptibility of Mice to Develop Intestinal Inflammation. Front Immunol 2018; 9:1166. [PMID: 29896196 PMCID: PMC5986922 DOI: 10.3389/fimmu.2018.01166] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 05/09/2018] [Indexed: 12/12/2022] Open
Abstract
Chronic intestinal inflammations are triggered by genetic and environmental components. However, it remains unclear how specific changes in the microbiota, host immunity, or pathogen exposure could promote the onset and exacerbation of these diseases. Here, we evaluated whether Salmonella enterica serovar Typhimurium (S. Typhimurium) infection increases the susceptibility to develop intestinal inflammation in mice. Two mouse models were used to evaluate the impact of S. Typhimurium infection: the chemical induction of colitis by dextran sulfate sodium (DSS) and interleukin (IL)-10−/− mice, which develop spontaneous intestinal inflammation. We observed that S. Typhimurium infection makes DSS-treated and IL-10−/− mice more susceptible to develop intestinal inflammation. Importantly, this increased susceptibility is associated to the ability of S. Typhimurium to persist in liver and spleen of infected mice, which depends on the virulence proteins secreted by Salmonella Pathogenicity Island 2-encoded type three secretion system (TTSS-2). Although immunization with a live attenuated vaccine resulted in a moderate reduction of the IL-10−/− mice susceptibility to develop intestinal inflammation due to previous S. Typhimurium infection, it did not prevent bacterial persistence. Our results suggest that persistent S. Typhimurium infection may increase the susceptibility of mice to develop inflammation in the intestine, which could be associated with virulence proteins secreted by TTSS-2.
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Affiliation(s)
- Bárbara M Schultz
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Geraldyne A Salazar
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Carolina A Paduro
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Catalina Pardo-Roa
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Daniela P Pizarro
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Francisco J Salazar-Echegarai
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Javiera Torres
- Departamento de Anatomía Patológica, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Claudia A Riedel
- Millennium Institute on Immunology and Immunotherapy, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Alexis M Kalergis
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Endocrinología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Manuel M Álvarez-Lobos
- Departamento de Gastroenterología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Susan M Bueno
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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40
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Ingram JP, Tursi S, Zhang T, Guo W, Yin C, A Wynosky-Dolfi M, van der Heijden J, Cai KQ, Yamamoto M, Finlay BB, Brodsky IE, Grivennikov SI, Tükel Ç, Balachandran S. A Nonpyroptotic IFN-γ-Triggered Cell Death Mechanism in Nonphagocytic Cells Promotes Salmonella Clearance In Vivo. THE JOURNAL OF IMMUNOLOGY 2018; 200:3626-3634. [PMID: 29654208 DOI: 10.4049/jimmunol.1701386] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 03/21/2018] [Indexed: 01/14/2023]
Abstract
The cytokine IFN-γ has well-established antibacterial properties against the bacterium Salmonella enterica in phagocytes, but less is known about the effects of IFN-γ on Salmonella-infected nonphagocytic cells, such as intestinal epithelial cells (IECs) and fibroblasts. In this article, we show that exposing human and murine IECs and fibroblasts to IFN-γ following infection with Salmonella triggers a novel form of cell death that is neither pyroptosis nor any of the major known forms of programmed cell death. Cell death required IFN-γ-signaling via STAT1-IRF1-mediated induction of guanylate binding proteins and the presence of live Salmonella in the cytosol. In vivo, ablating IFN-γ signaling selectively in murine IECs led to higher bacterial burden in colon contents and increased inflammation in the intestine of infected mice. Together, these results demonstrate that IFN-γ signaling triggers release of Salmonella from the Salmonella-containing vacuole into the cytosol of infected nonphagocytic cells, resulting in a form of nonpyroptotic cell death that prevents bacterial spread in the gut.
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Affiliation(s)
- Justin P Ingram
- Blood Cell Development and Function Program, Fox Chase Cancer Center, Philadelphia, PA 19111
| | - Sarah Tursi
- Department of Microbiology and Immunology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140
| | - Ting Zhang
- Blood Cell Development and Function Program, Fox Chase Cancer Center, Philadelphia, PA 19111
| | - Wei Guo
- Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, PA 19111.,Department of General Surgery, Qilu Hospital of Shandong University, Jinan 250012, China
| | - Chaoran Yin
- Blood Cell Development and Function Program, Fox Chase Cancer Center, Philadelphia, PA 19111
| | - Meghan A Wynosky-Dolfi
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104
| | - Joris van der Heijden
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T1Z4, Canada
| | - Kathy Q Cai
- Cancer Biology Program, Fox Chase Cancer Center, Philadelphia, PA 19111; and
| | - Masahiro Yamamoto
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka University Suita, Osaka 565-0871, Japan
| | - B Brett Finlay
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T1Z4, Canada
| | - Igor E Brodsky
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104
| | - Sergei I Grivennikov
- Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, PA 19111
| | - Çagla Tükel
- Department of Microbiology and Immunology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140
| | - Siddharth Balachandran
- Blood Cell Development and Function Program, Fox Chase Cancer Center, Philadelphia, PA 19111;
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41
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Miller KA, Garza-Mayers AC, Leung Y, Goldberg MB. Identification of interactions among host and bacterial proteins and evaluation of their role early during Shigella flexneri infection. MICROBIOLOGY-SGM 2018; 164:540-550. [PMID: 29488864 DOI: 10.1099/mic.0.000637] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Shigella species cause diarrhoea by invading and spreading through the epithelial layer of the human colon. The infection triggers innate immune responses in the host that the bacterium combats by translocating into the host cell cytosol via a type 3 secretion system bacterial effector proteins that interfere with host processes. We previously demonstrated that interaction of the Shigella type 3 secreted effector protein IcsB with the host protein Toca-1 inhibits the innate immune response microtubule-associated protein light-chain 3 (LC3)-associated phagocytosis, and that IcsB interaction with Toca-1 is required for inhibition of this host response. Here, we show that Toca-1 in vitro precipitated not only IcsB, but also the type 3 secreted proteins OspC3, IpgD and IpaB. OspC3 and IpgD precipitation with Toca-1 was dependent on IcsB. Early during infection, most of these proteins localized near intracellular Shigella. We examined whether interactions among these proteins restrict innate host cell responses other than LC3-associated phagocytosis. In infected cells, OspC3 blocks production and secretion of the mature pro-inflammatory cytokine IL-18; however, we found that interaction of OspC3 with IcsB, either directly or indirectly via Toca-1, was not required for OspC3-mediated restriction of IL-18 production. These results indicate that interactions of the host protein Toca-1 with a subset of type 3 effector proteins contribute to the established function of some, but not all involved, effector proteins.
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Affiliation(s)
- Kelly A Miller
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Cambridge, Massachusetts, USA.,Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Anna Cristina Garza-Mayers
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, USA.,Present address: Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Yiuka Leung
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA.,Present address: Department of Anesthesiology, The Hardin Memorial Hospital Foundation, Inc., Elizabethtown, Kentucky, USA
| | - Marcia B Goldberg
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Cambridge, Massachusetts, USA.,Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, USA
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42
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Controlled Activity of the Salmonella Invasion-Associated Injectisome Reveals Its Intracellular Role in the Cytosolic Population. mBio 2017; 8:mBio.01931-17. [PMID: 29208746 PMCID: PMC5717391 DOI: 10.1128/mbio.01931-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The Salmonella invasion-associated type III secretion system (T3SS1) is an essential virulence factor required for entry into nonphagocytic cells and consequent uptake into a Salmonella-containing vacuole (SCV). While Salmonella is typically regarded as a vacuolar pathogen, a subset of bacteria escape from the SCV in epithelial cells and eventually hyperreplicate in the cytosol. T3SS1 is downregulated following bacterial entry into mammalian cells, but cytosolic Salmonella cells are T3SS1 induced, suggesting prolonged or resurgent activity of T3SS1 in this population. In order to investigate the postinternalization contributions of T3SS1 to the Salmonella infectious cycle in epithelial cells, we bypassed its requirement for bacterial entry by tagging the T3SS1-energizing ATPase InvC at the C terminus with peptides that are recognized by bacterial tail-specific proteases. This caused a dramatic increase in InvC turnover which rendered even assembled injectisomes inactive. Bacterial strains conditionally expressing these unstable InvC variants were proficient for invasion but underwent rapid and sustained intracellular inactivation of T3SS1 activity when InvC expression ceased. This allowed us to directly implicate T3SS1 activity in cytosolic colonization and bacterial egress. We subsequently identified two T3SS1-delivered effectors, SopB and SipA, that are required for efficient colonization of the epithelial cell cytosol. Overall, our findings support a multifaceted, postinvasion role for T3SS1 and its effectors in defining the cytosolic population of intracellular Salmonella. A needle-like apparatus, the type III secretion system (T3SS) injectisome, is absolutely required for Salmonella enterica to enter epithelial cells; this requirement has hampered the analysis of its postentry contributions. To identify T3SS1-dependent intracellular activities, in this study we overcame this limitation by developing a conditional inactivation in the T3SS whereby T3SS activity is chemically induced during culture in liquid broth, permitting bacterial entry into epithelial cells, but is quickly and perpetually inactivated in the absence of inducer. In this sense, the mutant acts like wild-type bacteria when extracellular and as a T3SS mutant once it enters a host cell. This “conditional” mutant allowed us to directly link activity of this T3SS with nascent vacuole lysis, cytosolic proliferation, and cellular egress, demonstrating that the invasion-associated T3SS also contributes to essential intracellular stages of the S. enterica infectious cycle.
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43
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Métris A, Sudhakar P, Fazekas D, Demeter A, Ari E, Olbei M, Branchu P, Kingsley RA, Baranyi J, Korcsmáros T. SalmoNet, an integrated network of ten Salmonella enterica strains reveals common and distinct pathways to host adaptation. NPJ Syst Biol Appl 2017; 3:31. [PMID: 29057095 PMCID: PMC5647365 DOI: 10.1038/s41540-017-0034-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 09/19/2017] [Accepted: 09/22/2017] [Indexed: 12/31/2022] Open
Abstract
Salmonella enterica is a prominent bacterial pathogen with implications on human and animal health. Salmonella serovars could be classified as gastro-intestinal or extra-intestinal. Genome-wide comparisons revealed that extra-intestinal strains are closer relatives of gastro-intestinal strains than to each other indicating a parallel evolution of this trait. Given the complexity of the differences, a systems-level comparison could reveal key mechanisms enabling extra-intestinal serovars to cause systemic infections. Accordingly, in this work, we introduce a unique resource, SalmoNet, which combines manual curation, high-throughput data and computational predictions to provide an integrated network for Salmonella at the metabolic, transcriptional regulatory and protein-protein interaction levels. SalmoNet provides the networks separately for five gastro-intestinal and five extra-intestinal strains. As a multi-layered, multi-strain database containing experimental data, SalmoNet is the first dedicated network resource for Salmonella. It comprehensively contains interactions between proteins encoded in Salmonella pathogenicity islands, as well as regulatory mechanisms of metabolic processes with the option to zoom-in and analyze the interactions at specific loci in more detail. Application of SalmoNet is not limited to strain comparisons as it also provides a Salmonella resource for biochemical network modeling, host-pathogen interaction studies, drug discovery, experimental validation of novel interactions, uncovering new pathological mechanisms from emergent properties and epidemiological studies. SalmoNet is available at http://salmonet.org.
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Affiliation(s)
- Aline Métris
- Quadram Institute Bioscience, Norwich Research Park, Norwich, NR4 7UA UK.,Present Address: Safety and Environmental Assurance Centre, Unilever, Colworth Science Park, Sharnbrook, Bedfordshire UK
| | - Padhmanand Sudhakar
- Quadram Institute Bioscience, Norwich Research Park, Norwich, NR4 7UA UK.,Earlham Institute, Norwich Research Park, Norwich, NR4 7UZ UK
| | - David Fazekas
- Earlham Institute, Norwich Research Park, Norwich, NR4 7UZ UK.,Department of Genetics, Eötvös Loránd University, Pázmány P. s. 1C, H-1117 Budapest, Hungary
| | - Amanda Demeter
- Quadram Institute Bioscience, Norwich Research Park, Norwich, NR4 7UA UK.,Earlham Institute, Norwich Research Park, Norwich, NR4 7UZ UK.,Department of Genetics, Eötvös Loránd University, Pázmány P. s. 1C, H-1117 Budapest, Hungary
| | - Eszter Ari
- Department of Genetics, Eötvös Loránd University, Pázmány P. s. 1C, H-1117 Budapest, Hungary.,Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Marton Olbei
- Quadram Institute Bioscience, Norwich Research Park, Norwich, NR4 7UA UK.,Earlham Institute, Norwich Research Park, Norwich, NR4 7UZ UK
| | - Priscilla Branchu
- Quadram Institute Bioscience, Norwich Research Park, Norwich, NR4 7UA UK.,IRSD, Université de Toulouse, INSERM, INRA, ENVT, UPS, Toulouse, France
| | - Rob A Kingsley
- Quadram Institute Bioscience, Norwich Research Park, Norwich, NR4 7UA UK
| | - Jozsef Baranyi
- Quadram Institute Bioscience, Norwich Research Park, Norwich, NR4 7UA UK
| | - Tamas Korcsmáros
- Quadram Institute Bioscience, Norwich Research Park, Norwich, NR4 7UA UK.,Earlham Institute, Norwich Research Park, Norwich, NR4 7UZ UK
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44
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MacKenzie KD, Palmer MB, Köster WL, White AP. Examining the Link between Biofilm Formation and the Ability of Pathogenic Salmonella Strains to Colonize Multiple Host Species. Front Vet Sci 2017; 4:138. [PMID: 29159172 PMCID: PMC5581909 DOI: 10.3389/fvets.2017.00138] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Accepted: 08/09/2017] [Indexed: 12/11/2022] Open
Abstract
Salmonella are important pathogens worldwide and a predominant number of human infections are zoonotic in nature. The ability of strains to form biofilms, which is a multicellular behavior characterized by the aggregation of cells, is predicted to be a conserved strategy for increased persistence and survival. It may also contribute to the increasing number of infections caused by ingestion of contaminated fruits and vegetables. There is a correlation between biofilm formation and the ability of strains to colonize and replicate within the intestines of multiple host species. These strains predominantly cause localized gastroenteritis infections in humans. In contrast, there are salmonellae that cause systemic, disseminated infections in a select few host species; these “invasive” strains have a narrowed host range, and most are unable to form biofilms. This includes host-restricted Salmonella serovar Typhi, which are only able to infect humans, and atypical gastroenteritis strains associated with the opportunistic infection of immunocompromised patients. From the perspective of transmission, biofilm formation is advantageous for ensuring pathogen survival in the environment. However, from an infection point of view, biofilm formation may be an anti-virulence trait. We do not know if the capacity to form biofilms prevents a strain from accessing the systemic compartments within the host or if loss of the biofilm phenotype reflects a change in a strain’s interaction with the host. In this review, we examine the connections between biofilm formation, Salmonella disease states, degrees of host adaptation, and how this might relate to different transmission patterns. A better understanding of the dynamic lifecycle of Salmonella will allow us to reduce the burden of livestock and human infections caused by these important pathogens.
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Affiliation(s)
- Keith D MacKenzie
- Vaccine and Infectious Disease Organization-International Vaccine Centre, Saskatoon, SK, Canada.,Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Melissa B Palmer
- Vaccine and Infectious Disease Organization-International Vaccine Centre, Saskatoon, SK, Canada.,Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Wolfgang L Köster
- Vaccine and Infectious Disease Organization-International Vaccine Centre, Saskatoon, SK, Canada.,Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Aaron P White
- Vaccine and Infectious Disease Organization-International Vaccine Centre, Saskatoon, SK, Canada.,Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, Canada
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45
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Young AM, Palmer AE. Methods to Illuminate the Role of Salmonella Effector Proteins during Infection: A Review. Front Cell Infect Microbiol 2017; 7:363. [PMID: 28848721 PMCID: PMC5554337 DOI: 10.3389/fcimb.2017.00363] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 07/27/2017] [Indexed: 12/19/2022] Open
Abstract
Intracellular bacterial pathogens like Salmonella enterica use secretion systems, such as the Type III Secretion System, to deliver virulence factors into host cells in order to invade and colonize these cells. Salmonella virulence factors include a suite of effector proteins that remodel the host cell to facilitate bacterial internalization, replication, and evasion of host immune surveillance. A number of diverse and innovative approaches have been used to identify and characterize the role of effector proteins during infection. Recent techniques for studying infection using single cell and animal models have illuminated the contribution of individual effector proteins in infection. This review will highlight the techniques applied to study Salmonella effector proteins during infection. It will describe how different approaches have revealed mechanistic details for effectors in manipulating host cellular processes including: the dynamics of effector translocation into host cells, cytoskeleton reorganization, membrane trafficking, gene regulation, and autophagy.
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Affiliation(s)
- Alexandra M Young
- Department of Chemistry and Biochemistry, BioFrontiers Institute, University of Colorado BoulderBoulder, CO, United States
| | - Amy E Palmer
- Department of Chemistry and Biochemistry, BioFrontiers Institute, University of Colorado BoulderBoulder, CO, United States
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46
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Glasgow AA, Wong HT, Tullman-Ercek D. A Secretion-Amplification Role for Salmonella enterica Translocon Protein SipD. ACS Synth Biol 2017; 6:1006-1015. [PMID: 28301138 DOI: 10.1021/acssynbio.6b00335] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The bacterial type III secretion system (T3SS) is an important target for enabling high-titer production of proteins of biotechnological interest as well as for synthetic biology applications that rely on protein delivery to host cells. The T3SS forms a membrane-embedded needle complex that is capped by the translocon proteins and extends into the extracellular space. The needle tip complex in Salmonella enterica consists of three translocon proteins: SipB, SipC, and SipD. It is known that knocking out sipD disrupts T3SS regulation to cause constitutive secretion of native proteins. However, we discovered that complementation of SipD in trans via exogenous addition to T3SS-expressing cultures further improves heterologous protein secretion titers, suggesting a previously unknown but important role for this protein. Building on this knowledge, we have engineered a hyper-secreting strain of S. enterica for a greater than 100-fold improvement in the production of a variety of biotechnologically valuable heterologous proteins that are challenging to produce, such as toxic antimicrobial peptides and proteolysis-prone biopolymer proteins. We determined that transcription by several T3SS promoters is upregulated with the addition of SipD, that the N-terminal domain of SipD is sufficient to observe the increased secretion phenotype, and that the effect is post-transcriptional and post-translational. These results lend support to the use of bacterial secretion as a powerful protein production strategy, and the hypothesis that translocon proteins contribute to type III secretion regulation.
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Affiliation(s)
- Anum Azam Glasgow
- UC
Berkeley-UCSF Graduate Program in Bioengineering, University of California Berkeley, Berkeley, California 94720, United States
| | - Han Teng Wong
- Department
of Plant and Microbial Biology, University of California Berkeley, Berkeley, California 94720, United States
| | - Danielle Tullman-Ercek
- Department
of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States
- Center
for Synthetic Biology, Northwestern University, Evanston, Illinois 60208, United States
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47
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Finn CE, Chong A, Cooper KG, Starr T, Steele-Mortimer O. A second wave of Salmonella T3SS1 activity prolongs the lifespan of infected epithelial cells. PLoS Pathog 2017; 13:e1006354. [PMID: 28426838 PMCID: PMC5413073 DOI: 10.1371/journal.ppat.1006354] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 05/02/2017] [Accepted: 04/14/2017] [Indexed: 11/19/2022] Open
Abstract
Type III secretion system 1 (T3SS1) is used by the enteropathogen Salmonella enterica serovar Typhimurium to establish infection in the gut. Effector proteins translocated by this system across the plasma membrane facilitate invasion of intestinal epithelial cells. One such effector, the inositol phosphatase SopB, contributes to invasion and mediates activation of the pro-survival kinase Akt. Following internalization, some bacteria escape from the Salmonella-containing vacuole into the cytosol and there is evidence suggesting that T3SS1 is expressed in this subpopulation. Here, we investigated the post-invasion role of T3SS1, using SopB as a model effector. In cultured epithelial cells, SopB-dependent Akt phosphorylation was observed at two distinct stages of infection: during and immediately after invasion, and later during peak cytosolic replication. Single cell analysis revealed that cytosolic Salmonella deliver SopB via T3SS1. Although intracellular replication was unaffected in a SopB deletion mutant, cells infected with ΔsopB demonstrated a lack of Akt phosphorylation, earlier time to death, and increased lysis. When SopB expression was induced specifically in cytosolic Salmonella, these effects were restored to levels observed in WT infected cells, indicating that the second wave of SopB protects this infected population against cell death via Akt activation. Thus, T3SS1 has two, temporally distinct roles during epithelial cell colonization. Additionally, we found that delivery of SopB by cytosolic bacteria was translocon-independent, in contrast to canonical effector translocation across eukaryotic membranes, which requires formation of a translocon pore. This mechanism was also observed for another T3SS1 effector, SipA. These findings reveal the functional and mechanistic adaptability of a T3SS that can be harnessed in different microenvironments.
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Affiliation(s)
- Ciaran E. Finn
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Audrey Chong
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Kendal G. Cooper
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Tregei Starr
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Olivia Steele-Mortimer
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
- * E-mail:
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Sunkavalli U, Aguilar C, Silva RJ, Sharan M, Cruz AR, Tawk C, Maudet C, Mano M, Eulalio A. Analysis of host microRNA function uncovers a role for miR-29b-2-5p in Shigella capture by filopodia. PLoS Pathog 2017; 13:e1006327. [PMID: 28394930 PMCID: PMC5398735 DOI: 10.1371/journal.ppat.1006327] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 04/20/2017] [Accepted: 03/31/2017] [Indexed: 12/18/2022] Open
Abstract
MicroRNAs play an important role in the interplay between bacterial pathogens and host cells, participating as host defense mechanisms, as well as exploited by bacteria to subvert host cellular functions. Here, we show that microRNAs modulate infection by Shigella flexneri, a major causative agent of bacillary dysentery in humans. Specifically, we characterize the dual regulatory role of miR-29b-2-5p during infection, showing that this microRNA strongly favors Shigella infection by promoting both bacterial binding to host cells and intracellular replication. Using a combination of transcriptome analysis and targeted high-content RNAi screening, we identify UNC5C as a direct target of miR-29b-2-5p and show its pivotal role in the modulation of Shigella binding to host cells. MiR-29b-2-5p, through repression of UNC5C, strongly enhances filopodia formation thus increasing Shigella capture and promoting bacterial invasion. The increase of filopodia formation mediated by miR-29b-2-5p is dependent on RhoF and Cdc42 Rho-GTPases. Interestingly, the levels of miR-29b-2-5p, but not of other mature microRNAs from the same precursor, are decreased upon Shigella replication at late times post-infection, through degradation of the mature microRNA by the exonuclease PNPT1. While the relatively high basal levels of miR-29b-2-5p at the start of infection ensure efficient Shigella capture by host cell filopodia, dampening of miR-29b-2-5p levels later during infection may constitute a bacterial strategy to favor a balanced intracellular replication to avoid premature cell death and favor dissemination to neighboring cells, or alternatively, part of the host response to counteract Shigella infection. Overall, these findings reveal a previously unappreciated role of microRNAs, and in particular miR-29b-2-5p, in the interaction of Shigella with host cells.
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Affiliation(s)
- Ushasree Sunkavalli
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Carmen Aguilar
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Ricardo Jorge Silva
- UC-BIOTECH, Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Malvika Sharan
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Ana Rita Cruz
- UC-BIOTECH, Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Caroline Tawk
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Claire Maudet
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Miguel Mano
- UC-BIOTECH, Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Ana Eulalio
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
- UC-BIOTECH, Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- * E-mail:
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Tsou LK, Yount JS, Hang HC. Epigallocatechin-3-gallate inhibits bacterial virulence and invasion of host cells. Bioorg Med Chem 2017; 25:2883-2887. [PMID: 28325635 DOI: 10.1016/j.bmc.2017.03.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 11/28/2022]
Abstract
Increasing antibiotic resistance and beneficial effects of host microbiota has motivated the search for anti-infective agents that attenuate bacterial virulence rather than growth. For example, we discovered that specific flavonoids such as baicalein and quercetin from traditional medicinal plant extracts could attenuate Salmonella enterica serovar Typhimurium type III protein secretion and invasion of host cells. Here, we show epigallocatechin-3-gallate from green tea extracts also inhibits the activity of S. Typhimurium type III protein effectors and significantly reduces bacterial invasion into host cells. These results reveal additional dietary plant metabolites that can attenuate bacterial virulence and infection of host cells.
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Affiliation(s)
- Lun K Tsou
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY 10065, USA; Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Zhunan Town, Miaoli County 35053, Taiwan, ROC
| | - Jacob S Yount
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY 10065, USA; Department of Microbial Infection and Immunity, Center for Microbial Interface Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Howard C Hang
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY 10065, USA.
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Nazir R, Mazurier S, Yang P, Lemanceau P, van Elsas JD. The Ecological Role of Type Three Secretion Systems in the Interaction of Bacteria with Fungi in Soil and Related Habitats Is Diverse and Context-Dependent. Front Microbiol 2017; 8:38. [PMID: 28197129 PMCID: PMC5282467 DOI: 10.3389/fmicb.2017.00038] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 01/06/2017] [Indexed: 12/14/2022] Open
Abstract
Bacteria and fungi constitute important organisms in many ecosystems, in particular terrestrial ones. Both organismal groups contribute significantly to biogeochemical cycling processes. Ecological theory postulates that bacteria capable of receiving benefits from host fungi are likely to evolve efficient association strategies. The purpose of this review is to examine the mechanisms that underpin the bacterial interactions with fungi in soil and other systems, with special focus on the type III secretion system (T3SS). Starting with a brief description of the versatility of the T3SS as an interaction system with diverse eukaryotic hosts, we subsequently examine the recent advances made in our understanding of its contribution to interactions with soil fungi. The analysis used data sets ranging from circumstantial evidence to gene-knockout-based experimental data. The initial finding that the abundance of T3SSs in microbiomes is often enhanced in fungal-affected habitats like the mycosphere and the mycorrhizosphere is now substantiated with in-depth knowledge of the specific systems involved. Different fungal–interactive bacteria, in positive or negative associations with partner fungi, harbor and express T3SSs, with different ecological outcomes. In some particular cases, bacterial T3SSs have been shown to modulate the physiology of its fungal partner, affecting its ecological characteristics and consequently shaping its own habitat. Overall, the analyses of the collective data set revealed that diverse T3SSs have assumed diverse roles in the interactions of bacteria with host fungi, as driven by ecological and evolutionary niche requirements.
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Affiliation(s)
- Rashid Nazir
- Department of Environmental Sciences, COMSATS Institute of Information TechnologyAbbottabad, Pakistan; Department of Soil Environmental Science, Research Centre for Eco-environmental Sciences - Chinese Academy of SciencesBeijing, China
| | - Sylvie Mazurier
- Agroécologie, AgroSup Dijon, Institut National de la Recherche Agronomique, Université Bourgogne Franche-Comté Dijon, France
| | - Pu Yang
- Department of Microbial Ecology, GELIFES, University of Groningen Groningen, Netherlands
| | - Philippe Lemanceau
- Agroécologie, AgroSup Dijon, Institut National de la Recherche Agronomique, Université Bourgogne Franche-Comté Dijon, France
| | - Jan Dirk van Elsas
- Department of Microbial Ecology, GELIFES, University of Groningen Groningen, Netherlands
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