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Batani G, Vezzani G, Lashchuk S, Allaoui A, Cardamone D, Raso MM, Boero E, Roscioli E, Ridelfi M, Gasperini G, Pizza M, Rossi O, Berlanda Scorza F, Micoli F, Rappuoli R, Sala C. Development of a visual Adhesion/Invasion Inhibition Assay to assess the functionality of Shigella-specific antibodies. Front Immunol 2024; 15:1374293. [PMID: 38680489 PMCID: PMC11045934 DOI: 10.3389/fimmu.2024.1374293] [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: 01/21/2024] [Accepted: 04/01/2024] [Indexed: 05/01/2024] Open
Abstract
Introduction Shigella is the etiologic agent of a bacillary dysentery known as shigellosis, which causes millions of infections and thousands of deaths worldwide each year due to Shigella's unique lifestyle within intestinal epithelial cells. Cell adhesion/invasion assays have been extensively used not only to identify targets mediating host-pathogen interaction, but also to evaluate the ability of Shigella-specific antibodies to reduce virulence. However, these assays are time-consuming and labor-intensive and fail to assess differences at the single-cell level. Objectives and methods Here, we developed a simple, fast and high-content method named visual Adhesion/Invasion Inhibition Assay (vAIA) to measure the ability of anti-Shigellaantibodies to inhibit bacterial adhesion to and invasion of epithelial cells by using the confocal microscope Opera Phenix. Results We showed that vAIA performed well with a pooled human serum from subjects challenged with S. sonnei and that a specific anti-IpaD monoclonal antibody effectively reduced bacterial virulence in a dose-dependent manner. Discussion vAIA can therefore inform on the functionality of polyclonal and monoclonal responses thereby supporting the discovery of pathogenicity mechanisms and the development of candidate vaccines and immunotherapies. Lastly, this assay is very versatile and may be easily applied to other Shigella species or serotypes and to different pathogens.
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Affiliation(s)
- Giampiero Batani
- Monoclonal Antibody Discovery Laboratory, Fondazione Toscana Life Sciences, Siena, Italy
| | - Giacomo Vezzani
- GlaxoSmithKline (GSK) Vaccines Institute for Global Health (GVGH), Siena, Italy
| | - Sabrina Lashchuk
- Monoclonal Antibody Discovery Laboratory, Fondazione Toscana Life Sciences, Siena, Italy
| | - Abdelmounaaim Allaoui
- The Microbiology Laboratory, University Mohammed VI Polytechnic, Ben, Guerir, Morocco
| | - Dario Cardamone
- Data Science for Health Laboratory, Fondazione Toscana Life Sciences, Siena, Italy
| | | | - Elena Boero
- GlaxoSmithKline (GSK) Vaccines Institute for Global Health (GVGH), Siena, Italy
| | - Emanuele Roscioli
- Monoclonal Antibody Discovery Laboratory, Fondazione Toscana Life Sciences, Siena, Italy
| | - Matteo Ridelfi
- Monoclonal Antibody Discovery Laboratory, Fondazione Toscana Life Sciences, Siena, Italy
| | - Gianmarco Gasperini
- GlaxoSmithKline (GSK) Vaccines Institute for Global Health (GVGH), Siena, Italy
| | - Mariagrazia Pizza
- Department of Life Sciences, Imperial College, London, United Kingdom
| | - Omar Rossi
- GlaxoSmithKline (GSK) Vaccines Institute for Global Health (GVGH), Siena, Italy
| | | | - Francesca Micoli
- GlaxoSmithKline (GSK) Vaccines Institute for Global Health (GVGH), Siena, Italy
| | | | - Claudia Sala
- Monoclonal Antibody Discovery Laboratory, Fondazione Toscana Life Sciences, Siena, Italy
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Valenzuela-Valderas KN, Farrashzadeh E, Chang YY, Shi Y, Raudonis R, Leung BM, Rohde JR, Enninga J, Cheng Z. RACK1 promotes Shigella flexneri actin-mediated invasion, motility, and cell-to-cell spreading. iScience 2023; 26:108216. [PMID: 37953961 PMCID: PMC10637933 DOI: 10.1016/j.isci.2023.108216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 08/19/2023] [Accepted: 10/11/2023] [Indexed: 11/14/2023] Open
Abstract
Shigella flexneri is an intracellular bacterium that hijacks the host actin cytoskeleton to invade and disseminate within the colonic epithelium. Shigella's virulence factors induce actin polymerization, leading to bacterial uptake, actin tail formation, actin-mediated motility, and cell-to-cell spreading. Many host factors involved in the Shigella-prompted actin rearrangements remain elusive. Here, we studied the role of a host protein receptor for activated C kinase 1 (RACK1) in actin cytoskeleton dynamics and Shigella infection. We used time-lapse imaging to demonstrate that RACK1 facilitates Shigella-induced actin cytoskeleton remodeling at multiple levels during infection of epithelial cells. Silencing RACK1 expression impaired Shigella-induced rapid polymerizing structures, reducing host cell invasion, bacterial motility, and cell-to-cell spreading. In uninfected cells, RACK1 silencing reduced jasplakinolide-mediated filamentous actin aggregate formation and negatively affected actin turnover in fast polymerizing structures, such as membrane ruffles. Our findings provide a role of RACK1 in actin cytoskeleton dynamics and Shigella infection.
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Affiliation(s)
| | - Elmira Farrashzadeh
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Yuen-Yan Chang
- Unité Dynamique des interactions hôtes-pathogènes, Institut Pasteur and CNRS UMR3691, Université de Paris-Cité, 75724 Paris, France
| | - Yunnuo Shi
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Renee Raudonis
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Brendan M. Leung
- Department of Applied Oral Sciences, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - John R. Rohde
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Jost Enninga
- Unité Dynamique des interactions hôtes-pathogènes, Institut Pasteur and CNRS UMR3691, Université de Paris-Cité, 75724 Paris, France
| | - Zhenyu Cheng
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada
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3
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Wu J, Cai J, Tang Y, Lu B. The noncanonical inflammasome-induced pyroptosis and septic shock. Semin Immunol 2023; 70:101844. [PMID: 37778179 DOI: 10.1016/j.smim.2023.101844] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 09/10/2023] [Accepted: 09/22/2023] [Indexed: 10/03/2023]
Abstract
Sepsis remains one of the most common and lethal conditions globally. Currently, no proposed target specific to sepsis improves survival in clinical trials. Thus, an in-depth understanding of the pathogenesis of sepsis is needed to propel the discovery of effective treatment. Recently attention to sepsis has intensified because of a growing recognition of a non-canonical inflammasome-triggered lytic mode of cell death termed pyroptosis upon sensing cytosolic lipopolysaccharide (LPS). Although the consequences of activation of the canonical and non-canonical inflammasome are similar, the non-canonical inflammasome formation requires caspase-4/5/11, which enzymatically cleave the pore-forming protein gasdermin D (GSDMD) and thereby cause pyroptosis. The non-canonical inflammasome assembly triggers such inflammatory cell death by itself; or leverages a secondary activation of the canonical NLRP3 inflammasome pathway. Excessive cell death induced by oligomerization of GSDMD and NINJ1 leads to cytokine release and massive tissue damage, facilitating devastating consequences and death. This review summarized the updated mechanisms that initiate and regulate non-canonical inflammasome activation and pyroptosis and highlighted various endogenous or synthetic molecules as potential therapeutic targets for treating sepsis.
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Affiliation(s)
- Junru Wu
- Department of Cardiology, The 3rd Xiangya Hospital, Central South University, Changsha 410000, PR China
| | - Jingjing Cai
- Department of Cardiology, The 3rd Xiangya Hospital, Central South University, Changsha 410000, PR China
| | - Yiting Tang
- Department of Physiology, School of Basic Medical Science, Central South University, Changsha 410000, PR China
| | - Ben Lu
- Department of Critical Care Medicine and Hematology, The 3rd Xiangya Hospital, Central South University, Changsha 410000, PR China; Key Laboratory of Sepsis Translational Medicine of Hunan, Central South University, Changsha 410000, PR China.
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4
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Pakbin B, Brück WM, Brück TB. Molecular Mechanisms of Shigella Pathogenesis; Recent Advances. Int J Mol Sci 2023; 24:ijms24032448. [PMID: 36768771 PMCID: PMC9917014 DOI: 10.3390/ijms24032448] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/21/2023] [Accepted: 01/23/2023] [Indexed: 01/28/2023] Open
Abstract
Shigella species are the main cause of bacillary diarrhoea or shigellosis in humans. These organisms are the inhabitants of the human intestinal tract; however, they are one of the main concerns in public health in both developed and developing countries. In this study, we reviewed and summarised the previous studies and recent advances in molecular mechanisms of pathogenesis of Shigella Dysenteriae and non-Dysenteriae species. Regarding the molecular mechanisms of pathogenesis and the presence of virulence factor encoding genes in Shigella strains, species of this bacteria are categorised into Dysenteriae and non-Dysenteriae clinical groups. Shigella species uses attachment, invasion, intracellular motility, toxin secretion and host cell interruption mechanisms, causing mild diarrhoea, haemorrhagic colitis and haemolytic uremic syndrome diseases in humans through the expression of effector delivery systems, protein effectors, toxins, host cell immune system evasion and iron uptake genes. The investigation of these genes and molecular mechanisms can help us to develop and design new methods to detect and differentiate these organisms in food and clinical samples and determine appropriate strategies to prevent and treat the intestinal and extraintestinal infections caused by these enteric pathogens.
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Affiliation(s)
- Babak Pakbin
- Werner Siemens Chair of Synthetic Biotechnology, Department of Chemistry, Technical University of Munich (TUM), Lichtenberg Str. 4, 85748 Garching bei München, Germany
- Institute for Life Technologies, University of Applied Sciences Western Switzerland Valais-Wallis, 1950 Sion, Switzerland
| | - Wolfram Manuel Brück
- Institute for Life Technologies, University of Applied Sciences Western Switzerland Valais-Wallis, 1950 Sion, Switzerland
- Correspondence: (W.M.B.); (T.B.B.)
| | - Thomas B. Brück
- Werner Siemens Chair of Synthetic Biotechnology, Department of Chemistry, Technical University of Munich (TUM), Lichtenberg Str. 4, 85748 Garching bei München, Germany
- Correspondence: (W.M.B.); (T.B.B.)
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Abstract
Enteric bacterial infections contribute substantially to global disease burden and mortality, particularly in the developing world. In vitro 2D monolayer cultures have provided critical insights into the fundamental virulence mechanisms of a multitude of pathogens, including Salmonella enterica serovars Typhimurium and Typhi, Vibrio cholerae, Shigella spp., Escherichia coli and Campylobacter jejuni, which have led to the identification of novel targets for antimicrobial therapy and vaccines. In recent years, the arsenal of experimental systems to study intestinal infections has been expanded by a multitude of more complex models, which have allowed to evaluate the effects of additional physiological and biological parameters on infectivity. Organoids recapitulate the cellular complexity of the human intestinal epithelium while 3D bioengineered scaffolds and microphysiological devices allow to emulate oxygen gradients, flow and peristalsis, as well as the formation and maintenance of stable and physiologically relevant microbial diversity. Additionally, advancements in ex vivo cultures and intravital imaging have opened new possibilities to study the effects of enteric pathogens on fluid secretion, barrier integrity and immune cell surveillance in the intact intestine. This review aims to present a balanced and updated overview of current intestinal in vitro and ex vivo methods for modeling of enteric bacterial infections. We conclude that the different paradigms are complements rather than replacements and their combined use promises to further our understanding of host-microbe interactions and their impacts on intestinal health.
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Affiliation(s)
- Nayere Taebnia
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- CONTACT Ute Römling Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 77, Stockholm, Sweden
| | - Volker M. Lauschke
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
- Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart, Germany
- University of Tübingen, Tübingen, Germany
- Volker M. Lauschke Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77, Stockholm, Sweden
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Helminiak L, Mishra S, Keun Kim H. Pathogenicity and virulence of Rickettsia. Virulence 2022; 13:1752-1771. [PMID: 36208040 PMCID: PMC9553169 DOI: 10.1080/21505594.2022.2132047] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 09/16/2022] [Accepted: 09/29/2022] [Indexed: 12/24/2022] Open
Abstract
Rickettsiae include diverse Gram-negative microbial species that exhibit obligatory intracellular lifecycles between mammalian hosts and arthropod vectors. Human infections with arthropod-borne Rickettsia continue to cause significant morbidity and mortality as recent environmental changes foster the proliferation of arthropod vectors and increased exposure to humans. However, the technical difficulties in working with Rickettsia have delayed our progress in understanding the molecular mechanisms involved in rickettsial pathogenesis and disease transmission. Recent advances in developing genetic tools for Rickettsia have enabled investigators to identify virulence genes, uncover molecular functions, and characterize host responses to rickettsial determinants. Therefore, continued efforts to determine virulence genes and their biological functions will help us understand the underlying mechanisms associated with arthropod-borne rickettsioses.
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Affiliation(s)
| | | | - Hwan Keun Kim
- Center for Infectious Diseases, Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY, USA
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7
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Qiu S, Liu K, Yang C, Xiang Y, Min K, Zhu K, Liu H, Du X, Yang M, Wang L, Sun Y, Zhou H, Mahe M, Zhao J, Li S, Yu D, Hawkey J, Holt KE, Baker S, Yang J, Xu X, Song H. A Shigella sonnei clone with extensive drug resistance associated with waterborne outbreaks in China. Nat Commun 2022; 13:7365. [PMID: 36450777 PMCID: PMC9709761 DOI: 10.1038/s41467-022-35136-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 11/21/2022] [Indexed: 12/05/2022] Open
Abstract
Antimicrobial resistance of Shigella sonnei has become a global concern. Here, we report a phylogenetic group of S. sonnei with extensive drug resistance, including a combination of multidrug resistance, coresistance to ceftriaxone and azithromycin (cefRaziR), reduced susceptibility to fluoroquinolones, and even colistin resistance (colR). This distinct clone caused six waterborne shigellosis outbreaks in China from 2015 to 2020. We collect 155 outbreak isolates and 152 sporadic isolates. The cefRaziR isolates, including outbreak strains, are mainly distributed in a distinct clade located in global Lineage III. The outbreak strains form a recently derived monophyletic group that may have emerged circa 2010. The cefRaziR and colR phenotypes are attributed to the acquisition of different plasmids, particularly the IncB/O/K/Z plasmid coharboring the blaCTX-M-14, mphA, aac(3)-IId, dfrA17, aadA5, and sul1 genes and the IncI2 plasmid with an mcr-1 gene. Genetic analyses identify 92 accessory genes and 60 single-nucleotide polymorphisms associated with the cefRaziR phenotype. Surveillance of this clone is required to determine its dissemination and threat to global public health.
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Affiliation(s)
- Shaofu Qiu
- grid.488137.10000 0001 2267 2324The Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Kangkang Liu
- grid.488137.10000 0001 2267 2324The Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Chaojie Yang
- grid.488137.10000 0001 2267 2324The Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Ying Xiang
- grid.488137.10000 0001 2267 2324The Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Kaiyuan Min
- grid.506261.60000 0001 0706 7839State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Kunpeng Zhu
- grid.488137.10000 0001 2267 2324The Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Hongbo Liu
- grid.488137.10000 0001 2267 2324The Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Xinying Du
- grid.488137.10000 0001 2267 2324The Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Mingjuan Yang
- grid.488137.10000 0001 2267 2324The Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Ligui Wang
- grid.488137.10000 0001 2267 2324The Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Yong Sun
- grid.410620.10000 0004 1757 8298Anhui Provincial Center for Disease Control and Prevention, Hefei, China
| | - Haijian Zhou
- grid.198530.60000 0000 8803 2373National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention and State Key Laboratory for Infectious Disease Prevention and Control, Beijing, China
| | - Muti Mahe
- Center for Disease Control and Prevention of Xinjiang Uygur Autonomous Region, Urumqi, China
| | - Jiayong Zhao
- grid.418504.cHenan Provincial Center for Disease Control and Prevention, Zhengzhou, China
| | - Shijun Li
- Guizhou Provincial Center for Disease Control and Prevention, Guiyang, China
| | - Deshan Yu
- grid.508057.fGansu Provincial Center for Disease Control and Prevention, Lanzhou, China
| | - Jane Hawkey
- grid.1002.30000 0004 1936 7857Department of Infectious Diseases, Monash University, Melbourne, VIC Australia
| | - Kathryn E. Holt
- grid.1002.30000 0004 1936 7857Department of Infectious Diseases, Monash University, Melbourne, VIC Australia
| | - Stephen Baker
- grid.5335.00000000121885934University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Juntao Yang
- grid.506261.60000 0001 0706 7839State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Xuebin Xu
- grid.430328.eShanghai Municipal Center for Disease Control and Prevention, Shanghai, China
| | - Hongbin Song
- grid.488137.10000 0001 2267 2324The Chinese PLA Center for Disease Control and Prevention, Beijing, China
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Wang M, Zhan X, Ma X, Wang R, Guo D, Zhang Y, Yu J, Chang Y, Lü X, Shi C. Antibacterial Activity of Thymoquinone Against Shigella flexneri and Its Effect on Biofilm Formation. Foodborne Pathog Dis 2022; 19:767-778. [PMID: 36367548 DOI: 10.1089/fpd.2022.0056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Thymoquinone (TQ) has been demonstrated to have anti-cancer, anti-inflammatory, antioxidant, and anti-diabetic activities. Shigella flexneri is the main pathogen causing shigellosis in developing countries. In this study, the antibacterial activity of TQ against S. flexneri and its possible antibacterial mechanism were studied. In addition, the inhibitory effect of TQ on the formation of S. flexneri biofilm was also investigated. The results showed that both the minimum inhibitory concentration and the minimum bactericidal concentration of TQ against S. flexneri ATCC 12022 were 0.2 mg/mL. After treatment with TQ at 0.4 mg/mL in Luria-Bertani broth for 3 h, or treatment with 0.2 mg/mL TQ in phosphate-buffered saline for 60 min, the number of S. flexneri (initial number is 6.5 log colony-forming units/mL) dropped below the detection limit. TQ also displayed good antibacterial activity in contaminated lettuce juice. TQ caused an increase in intracellular reactive oxygen species level, a decrease in intracellular adenosine triphosphate (ATP) concentration, a change in the intracellular protein, damage to cell membrane integrity and changes in cell morphology. In addition, TQ showed the ability to inhibit the formation of S. flexneri biofilm; treatment resulted in a decrease in the amount of biofilm and extracellular polysaccharides, and the destruction of biofilm structure. These findings indicated that TQ had strong antimicrobial and antibiofilm activities and a potential to be applied in the fruit and vegetable processing industry or other food industries to control S. flexneri.
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Affiliation(s)
- Muxue Wang
- College of Food Science and Engineering, Northwest A&F University, Yangling, China
| | - Xiangjun Zhan
- College of Food Science and Engineering, Northwest A&F University, Yangling, China
| | - Xiao Ma
- College of Food Science and Engineering, Northwest A&F University, Yangling, China
| | - Ruixia Wang
- College of Food Science and Engineering, Northwest A&F University, Yangling, China
| | - Du Guo
- College of Food Science and Engineering, Northwest A&F University, Yangling, China
| | - Yingying Zhang
- College of Food Science and Engineering, Northwest A&F University, Yangling, China
| | - Jiangtao Yu
- Yangling Hesheng Irradiation Technologies Co., Ltd., Yangling, China
| | - Yunhe Chang
- Food and Pharmaceutical Engineering Institute, Guiyang University, Guiyang, China
| | - Xin Lü
- College of Food Science and Engineering, Northwest A&F University, Yangling, China
| | - Chao Shi
- College of Food Science and Engineering, Northwest A&F University, Yangling, China
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Invading Bacterial Pathogens Activate Transcription Factor EB in Epithelial Cells through the Amino Acid Starvation Pathway of mTORC1 Inhibition. Mol Cell Biol 2022; 42:e0024122. [PMID: 36005752 PMCID: PMC9476939 DOI: 10.1128/mcb.00241-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Upon pathogen infection, intricate innate signaling cascades are induced to initiate the transcription of immune effectors, including cytokines and chemokines. Transcription factor EB (TFEB), a master regulator of lysosomal biogenesis and autophagy genes, was found recently to be a novel regulator of innate immunity in both Caenorhabditis elegans and mammals. Despite TFEB participating in critical mechanisms of pathogen recognition and in the transcriptional response to infection in mammalian macrophages, little is known about its roles in the infected epithelium or infected nonimmune cells in general. Here, we demonstrate that TFEB is activated in nonimmune cells upon infection with bacterial pathogens through a pathway dependent on mTORC1 inhibition and RAG-GTPase activity, reflecting the importance of membrane damage and amino acid starvation responses during infection. Additionally, we present data demonstrating that although TFEB does not affect bacterial killing or load in nonimmune cells, it alters the host transcriptome upon infection, thus promoting an antibacterial transcriptomic landscape. Elucidating the roles of TFEB in infected nonimmune cells and the upstream signaling cascade provides critical insight into understanding how cells recognize and respond to bacterial pathogens.
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Khatua A, Prasad A, Behuria HG, Patel AK, Singh M, Yasasve M, Saravanan M, Meena R. Evaluation of antimicrobial, anticancer potential and Flippase induced leakage in model membrane of Centella asiatica fabricated MgONPs. BIOMATERIALS ADVANCES 2022; 138:212855. [PMID: 35913247 DOI: 10.1016/j.bioadv.2022.212855] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 04/24/2022] [Accepted: 05/09/2022] [Indexed: 12/26/2022]
Abstract
The use of chemically synthesized nanoparticles and crude plant extracts as antimicrobial -anticancer agents have many limitations. In this study, we have used Centella asiatica extract (CaE) having relatively less explored but tremendous medicinal properties, as reducing and stabilizing agents to green synthesize magnesium oxide nanoparticles (MgONPs) using magnesium nitrate. In comparison to the bulk material, capabilities of Ca-MgONPs as an improved antibacterial, antifungal, and anticancer agent in human prostatic carcinoma cells (PC3), as well as membranolytic capability in model cell membrane, were studied. The phyto-functionalized Ca-MgONPs were characterized using UV-Visible spectroscopy (UV-Vis), Transmission Electron Microscopy (TEM), Energy Dispersive X-Ray Spectroscopy (EDX), X-ray Diffraction (XRD), Fourier Transform Infra-Red Spectroscopy (FT-IR) and Atomic Force Microscopy (AFM). Observation of characteristic peaks by spectroscopic and microscopic analysis confirmed the synthesis of Ca-MgONPs. The Ca-MgONPs showed broad spectrum of bactericidal activity against both gram-positive and gram-negative bacteria and fungicidal activity against two species of the Candida fungus. The Ca-MgONPs also exhibited dose-dependent and selective inhibition of proliferating PC3 cells with IC50 of 123.65 ± 4.82 μg/mL at 24 h, however, without having any cytotoxicity toward non-cancerous HEK293 cells. Further studies aimed at understanding the probable mechanism of toxicity of Ca-MgONPs in PC3 cells, the results indicated a significant reduction in cell migration capacities, increment in cytosolic ROS, loss of mitochondrial transmembrane potential, DNA damage and S-phase cell cycle arrest. Ca-MgONPs also induced pore formation in a synthetic large unilamellar vesicle. Thus, Ca-MgONPs might be useful in the effective management of several human pathogens of concern and some more cancer types.
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Affiliation(s)
- Ashapurna Khatua
- Nanotoxicology Laboratory, Lab#312, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Abhinav Prasad
- Biochemistry and Environmental Toxicology Laboratory, Lab#103, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Himadri Gourav Behuria
- Department of Biotechnology, North Orissa University, Mayurbhanj, Baripada, Odisha 757003, India
| | - Amiya Kumar Patel
- School of Biotechnology and Bioinformatics, Sambalpur University, Sambalpur, Odisha 768019, India
| | - Mani Singh
- Department of Environmental Sciences, Lakshmibai College, University of Delhi, New Delhi 110052, India
| | - Madhavan Yasasve
- Department of Oral Medicine and Radiology, Faculty of Dental Sciences, Sri Ramachandra Institute of Higher Education and Research, Chennai 600116, India
| | - Muthupandian Saravanan
- AMR and Nanomedicine Laboratory, Department of Pharmacology, Saveetha Dental College, Saveetha Institute of Medical and Technical Sciences (SIMATS), Chennai 600077, India.
| | - Ramovatar Meena
- Nanotoxicology Laboratory, Lab#312, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
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Wood TE, Westervelt KA, Yoon JM, Eshleman HD, Levy R, Burnes H, Slade DJ, Lesser CF, Goldberg MB. The Shigella Spp. Type III Effector Protein OspB Is a Cysteine Protease. mBio 2022; 13:e0127022. [PMID: 35638611 PMCID: PMC9239218 DOI: 10.1128/mbio.01270-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 05/05/2022] [Indexed: 11/20/2022] Open
Abstract
The type III secretion system is required for virulence of many pathogenic bacteria. Bacterial effector proteins delivered into target host cells by this system modulate host signaling pathways and processes in a manner that promotes infection. Here, we define the activity of the effector protein OspB of the human pathogen Shigella spp., the etiological agent of shigellosis and bacillary dysentery. Using the yeast Saccharomyces cerevisiae as a model organism, we show that OspB sensitizes cells to inhibition of TORC1, the central regulator of growth and metabolism. In silico analyses reveal that OspB bears structural homology to bacterial cysteine proteases that target mammalian cell processes, and we define a conserved cysteine-histidine catalytic dyad required for OspB function. Using yeast genetic screens, we identify a crucial role for the arginine N-degron pathway in the yeast growth inhibition phenotype and show that inositol hexakisphosphate is an OspB cofactor. We find that a yeast substrate for OspB is the TORC1 component Tco89p, proteolytic cleavage of which generates a C-terminal fragment that is targeted for degradation via the arginine N-degron pathway; processing and degradation of Tco89p is required for the OspB phenotype. In all, we demonstrate that the Shigella T3SS effector OspB is a cysteine protease and decipher its interplay with eukaryotic cell processes. IMPORTANCEShigella spp. are important human pathogens and among the leading causes of diarrheal mortality worldwide, especially in children. Virulence depends on the Shigella type III secretion system (T3SS). Definition of the roles of the bacterial effector proteins secreted by the T3SS is key to understanding Shigella pathogenesis. The effector protein OspB contributes to a range of phenotypes during infection, yet the mechanism of action is unknown. Here, we show that S. flexneri OspB possesses cysteine protease activity in both yeast and mammalian cells, and that enzymatic activity of OspB depends on a conserved cysteine-histidine catalytic dyad. We determine how its protease activity sensitizes cells to TORC1 inhibition in yeast, finding that OspB cleaves a component of yeast TORC1, and that the degradation of the C-terminal cleavage product is responsible for OspB-mediated hypersensitivity to TORC1 inhibitors. Thus, OspB is a cysteine protease that depends on a conserved cysteine-histidine catalytic dyad.
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Affiliation(s)
- Thomas E. Wood
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Kathleen A. Westervelt
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Jessica M. Yoon
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Heather D. Eshleman
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Roie Levy
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Henry Burnes
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Daniel J. Slade
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
| | - Cammie F. Lesser
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Marcia B. Goldberg
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA
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12
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Dhanda AS, Guttman JA. Localization of host endocytic and actin-associated proteins during Shigella flexneri intracellular motility and intercellular spreading. Anat Rec (Hoboken) 2022; 306:1088-1110. [PMID: 35582740 DOI: 10.1002/ar.24955] [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: 02/28/2022] [Revised: 04/24/2022] [Accepted: 04/27/2022] [Indexed: 11/10/2022]
Abstract
Shigella flexneri (S. flexneri), the causative agent of bacillary dysentery, uses an effector-mediated strategy to hijack host cells and cause disease. To propagate and spread within human tissues, S. flexneri bacteria commandeer the host actin cytoskeleton to generate slender actin-rich comet tails to move intracellularly, and later, plasma membrane actin-based protrusions to move directly between adjacent host cells. To facilitate intercellular bacterial spreading, large micron-sized endocytic-like membrane invaginations form at the periphery of neighboring host cells that come into contact with S. flexneri-containing membrane protrusions. While S. flexneri comet tails and membrane protrusions consist primarily of host actin cytoskeletal proteins, S. flexneri membrane invaginations remain poorly understood with only clathrin and the clathrin adapter epsin-1 localized to the structures. Tangentially, we recently reported that Listeria monocytogenes, another actin-hijacking pathogen, exploits an assortment of caveolar and actin-bundling proteins at their micron-sized membrane invaginations formed during their cell-to-cell movement. Thus, to further characterize the S. flexneri disease process, we set out to catalog the distribution of a variety of actin-associated and caveolar proteins during S. flexneri actin-based motility and cell-to-cell spreading. Here we show that actin-associated proteins found at L. monocytogenes comet tails and membrane protrusions mimic those present at S. flexneri comet tails with the exception of α-actinins 1 and 4, which were shed from S. flexneri membrane protrusions. We also demonstrate that all known host endocytic components found at L. monocytogenes membrane invaginations are also present at those formed during S. flexneri infections.
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Affiliation(s)
- Aaron Singh Dhanda
- Department of Biological Sciences, Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Julian Andrew Guttman
- Department of Biological Sciences, Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, British Columbia, Canada
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13
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Köseoğlu VK, Jones MK, Agaisse H. The type 3 secretion effector IpgD promotes S. flexneri dissemination. PLoS Pathog 2022; 18:e1010324. [PMID: 35130324 PMCID: PMC8853559 DOI: 10.1371/journal.ppat.1010324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 02/17/2022] [Accepted: 01/31/2022] [Indexed: 12/15/2022] Open
Abstract
The bacterial pathogen Shigella flexneri causes 270 million cases of bacillary dysentery worldwide every year, resulting in more than 200,000 deaths. S. flexneri pathogenic properties rely on its ability to invade epithelial cells and spread from cell to cell within the colonic epithelium. This dissemination process relies on actin-based motility in the cytosol of infected cells and formation of membrane protrusions that project into adjacent cells and resolve into double-membrane vacuoles (DMVs) from which the pathogen escapes, thereby achieving cell-to-cell spread. S. flexneri dissemination is facilitated by the type 3 secretion system (T3SS) through poorly understood mechanisms. Here, we show that the T3SS effector IpgD facilitates the resolution of membrane protrusions into DMVs during S. flexneri dissemination. The phosphatidylinositol 4-phosphatase activity of IpgD decreases PtdIns(4,5)P2 levels in membrane protrusions, thereby counteracting de novo cortical actin formation in protrusions, a process that restricts the resolution of protrusions into DMVs. Finally, using an infant rabbit model of shigellosis, we show that IpgD is required for efficient cell-to-cell spread in vivo and contributes to the severity of dysentery. The intracellular pathogen Shigella flexneri is the causative agent of bacillary dysentery (blood in stool). Invasion of epithelial cells and cell-to-cell spread are critical determinants of S. flexneri pathogenesis. Cell-to-cell spread relies on the formation of membrane protrusions that project into adjacent cells and resolve into vacuoles. The molecular mechanisms supporting this dissemination process are poorly understood. In this study, we show that S. flexneri employs the phosphatidylinositol phosphatase activity of the T3SS effector protein IpgD to manipulate phosphoinositides in the protrusion membrane. Manipulation of phosphoinositide signaling restricts the formation of actin networks underneath the protrusion membrane, which would otherwise prevent the scission of protrusions into vacuoles. We also demonstrate that IpgD is required for efficient dissemination in the colon of infant rabbits and contributes to the severity of disease. This study exemplifies how manipulation of phosphoinositide signaling by intracellular pathogens supports bacterial pathogenesis.
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Affiliation(s)
- Volkan K. Köseoğlu
- Department of Microbiology, Immunology, and Cancer Biology, School of Medicine, University of Virginia, Charlottesville, Virginia, United States of America
| | - Marieke K. Jones
- Claude Moore Health Sciences Library, University of Virginia, Charlottesville, Virginia, United States of America
| | - Hervé Agaisse
- Department of Microbiology, Immunology, and Cancer Biology, School of Medicine, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail:
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14
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Song Y, Ma F, Sun M, Mu G, Tuo Y. The Chemical Structure Properties and Promoting Biofilm Activity of Exopolysaccharide Produced by Shigella flexneri. Front Microbiol 2022; 12:807397. [PMID: 35185832 PMCID: PMC8854994 DOI: 10.3389/fmicb.2021.807397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 12/23/2021] [Indexed: 11/17/2022] Open
Abstract
Shigella flexneri is a waterborne and foodborne pathogen that can damage human health. The exopolysaccharides (S-EPS) produced by S. flexneri CMCC51574 were found to promote biofilm formation and virulence. In this research, the crude S-EPS produced by S. flexneri CMCC51574 were separated into three main different fractions, S-EPS 1-1, S-EPS 2-1, and S-EPS 3-1. The structure of the S-ESP 2-1 was identified by FT-IR, ion chromatography analysis, methylation analysis, and NMR analysis. The main chain of S-EPS 2-1 was α-Manp-(1 → 3)-α-Manp-[(1 → 2,6)-α-Manp]15-[(1 → 2)-Manf-(1→]8; there were two branched-chain R1 and R2 with a ratio of 4:1, R1: α-Manp-(1 → 6)- and R2: α-Manp-(1 → 6)- Glc-(1 → 6)- were linked with (1 → 2,6)-α-Manp. It was found that S-EPS 2-1 exhibited the highest promoting effect on biofilm formation of S. flexneri. The S-EPS 2-1 was identified to interact with extracellular DNA (eDNA) of S. flexneri, indicating that the S-EPS 2-1 was the specific polysaccharide in the spatial structure of biofilm formation. Our research found the important role of S-EPS in S. flexneri biofilm formation, which will help us to understand the underlining mechanisms of the biofilm formation and find effective ways to prevent S. flexneri biofilm infection.
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Affiliation(s)
- Yinglong Song
- School of Food Science and Technology, Dalian Polytechnic University, Dalian, China
| | - Fenglian Ma
- School of Food Science and Technology, Dalian Polytechnic University, Dalian, China
| | - Mengying Sun
- School of Food Science and Technology, Dalian Polytechnic University, Dalian, China
| | - Guangqing Mu
- School of Food Science and Technology, Dalian Polytechnic University, Dalian, China
- Dalian Probiotics Function Research Key Laboratory, Dalian Polytechnic University, Dalian, China
| | - Yanfeng Tuo
- School of Food Science and Technology, Dalian Polytechnic University, Dalian, China
- *Correspondence: Yanfeng Tuo,
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15
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The type three secretion system effector protein IpgB1 promotes Shigella flexneri cell-to-cell spread through double-membrane vacuole escape. PLoS Pathog 2022; 18:e1010380. [PMID: 35202448 PMCID: PMC8903249 DOI: 10.1371/journal.ppat.1010380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 03/08/2022] [Accepted: 02/18/2022] [Indexed: 12/11/2022] Open
Abstract
S. flexneri is an important human pathogen that causes bacillary dysentery. During infection, S. flexneri invades colonic epithelial cells, hijacks the host cell cytoskeleton to move in the cytosol of infected cells, and spreads from cell to cell through formation of membrane protrusions that project into adjacent cells and resolve into double membrane vacuoles (DMVs). S. flexneri cell-to-cell spread requires the integrity of the bacterial type three secretion system (T3SS). However, the exact role of the T3SS effector proteins in the dissemination process remains poorly understood. Here, we investigated the role of the T3SS effector protein IpgB1 in S. flexneri dissemination. IpgB1 was previously characterized as a guanine nucleotide exchange factor (GEF) that contributes to invasion. In addition to the invasion defect, we showed that the ipgB1 mutant formed smaller infection foci in HT-29 cells. Complementation of this phenotype required the GEF activity of IpgB1. Using live confocal microscopy, we showed that the ipgB1 mutant is specifically impaired in DMV escape. Depletion of Rac1, the host cell target of IpgB1 during invasion, as well as pharmacological inhibition of Rac1 signaling, reduced cell-to-cell spread and DMV escape. In a targeted siRNA screen, we uncovered that RhoA depletion restored ipgB1 cell-to-cell spread and DMV escape, revealing a critical role for the IpgB1-Rac1 axis in antagonizing RhoA-mediated restriction of DMV escape. Using an infant rabbit model of shigellosis, we showed that the ipgB1 mutant formed fewer and smaller infection foci in the colon of infected animals, which correlated with attenuated symptoms of disease, including epithelial fenestration and bloody diarrhea. Our results demonstrate that, in addition to its role during invasion, IpgB1 modulates Rho family small GTPase signaling to promote cell-to-cell spread, DMV escape, and S. flexneri pathogenesis.
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16
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Herath TUB, Roy A, Gianfelice A, Ireton K. Shigella flexneri subverts host polarized exocytosis to enhance cell-to-cell spread. Mol Microbiol 2021; 116:1328-1346. [PMID: 34608697 DOI: 10.1111/mmi.14827] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 09/21/2021] [Accepted: 10/01/2021] [Indexed: 11/28/2022]
Abstract
Shigella flexneri is a gram-negative bacterial pathogen that causes dysentery. Critical for disease is the ability of Shigella to use an actin-based motility (ABM) process to spread between cells of the colonic epithelium. ABM transports bacteria to the periphery of host cells, allowing the formation of plasma membrane protrusions that mediate spread to adjacent cells. Here we demonstrate that efficient protrusion formation and cell-to-cell spread of Shigella involves bacterial stimulation of host polarized exocytosis. Using an exocytic probe, we found that exocytosis is locally upregulated in bacterial protrusions in a manner that depends on the Shigella type III secretion system. Experiments involving RNA interference (RNAi) indicate that efficient bacterial protrusion formation and spread require the exocyst, a mammalian multi-protein complex known to mediate polarized exocytosis. In addition, the exocyst component Exo70 and the exocyst regulator RalA were recruited to Shigella protrusions, suggesting that bacteria manipulate exocyst function. Importantly, RNAi-mediated depletion of exocyst proteins or RalA reduced the frequency of protrusion formation and also the lengths of protrusions, demonstrating that the exocyst controls both the initiation and elongation of protrusions. Collectively, our results reveal that Shigella co-opts the exocyst complex to disseminate efficiently in host cell monolayers.
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Affiliation(s)
- Thilina U B Herath
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Arpita Roy
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Antonella Gianfelice
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Keith Ireton
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
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17
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Kutsch M, González-Prieto C, Lesser CF, Coers J. The GBP1 microcapsule interferes with IcsA-dependent septin cage assembly around Shigella flexneri. Pathog Dis 2021; 79:6246431. [PMID: 33885766 DOI: 10.1093/femspd/ftab023] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 04/08/2021] [Indexed: 12/20/2022] Open
Abstract
Many cytosolic bacterial pathogens hijack the host actin polymerization machinery to form actin tails that promote direct cell-to-cell spread, enabling these pathogens to avoid extracellular immune defenses. However, these pathogens are still susceptible to intracellular cell-autonomous immune responses that restrict bacterial actin-based motility. Two classes of cytosolic antimotility factors, septins and guanylate-binding proteins (GBPs), have recently been established to block actin tail formation by the human-adapted bacterial pathogen Shigella flexneri. Both septin cages and GBP1 microcapsules restrict S. flexneri cell-to-cell spread by blocking S. flexneri actin-based motility. While septins assemble into cage-like structures around immobile S. flexneri, GBP1 forms microcapsules around both motile and immobile bacteria. The interplay between these two defense programs remains elusive. Here, we demonstrate that GBP1 microcapsules block septin cage assembly, likely by interfering with the function of S. flexneri IcsA, the outer membrane protein that promotes actin-based motility, as this protein is required for septin cage formation. However, S. flexneri that escape from GBP1 microcapsules via the activity of IpaH9.8, a type III secreted effector that promotes the degradation of GBPs, are often captured within septin cages. Thus, our studies reveal how septin cages and GBP1 microcapsules represent complementary host cell antimotility strategies.
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Affiliation(s)
- Miriam Kutsch
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Coral González-Prieto
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA 02115, USA.,Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Cammie F Lesser
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA 02115, USA.,Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Jörn Coers
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA.,Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
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18
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The Shigella Type III Secretion System: An Overview from Top to Bottom. Microorganisms 2021; 9:microorganisms9020451. [PMID: 33671545 PMCID: PMC7926512 DOI: 10.3390/microorganisms9020451] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 02/16/2021] [Accepted: 02/18/2021] [Indexed: 12/16/2022] Open
Abstract
Shigella comprises four species of human-restricted pathogens causing bacillary dysentery. While Shigella possesses multiple genetic loci contributing to virulence, a type III secretion system (T3SS) is its primary virulence factor. The Shigella T3SS nanomachine consists of four major assemblies: the cytoplasmic sorting platform; the envelope-spanning core/basal body; an exposed needle; and a needle-associated tip complex with associated translocon that is inserted into host cell membranes. The initial subversion of host cell activities is carried out by the effector functions of the invasion plasmid antigen (Ipa) translocator proteins, with the cell ultimately being controlled by dedicated effector proteins that are injected into the host cytoplasm though the translocon. Much of the information now available on the T3SS injectisome has been accumulated through collective studies on the T3SS from three systems, those of Shigella flexneri, Salmonella typhimurium and Yersinia enterocolitica/Yersinia pestis. In this review, we will touch upon the important features of the T3SS injectisome that have come to light because of research in the Shigella and closely related systems. We will also briefly highlight some of the strategies being considered to target the Shigella T3SS for disease prevention.
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19
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Dhanda AS, Yang D, Guttman JA. Localization of alpha-actinin-4 during infections by actin remodeling bacteria. Anat Rec (Hoboken) 2020; 304:1400-1419. [PMID: 33099893 DOI: 10.1002/ar.24548] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 08/13/2020] [Accepted: 09/12/2020] [Indexed: 11/12/2022]
Abstract
Bacterial pathogens cause disease by subverting the structure and function of their target host cells. Several foodborne agents such as Listeria monocytogenes (L. monocytogenes), Shigella flexneri (S. flexneri), Salmonella enterica serovar Typhimurium (S. Typhimurium) and enteropathogenic Escherichia coli (EPEC) manipulate the host actin cytoskeleton to cause diarrheal (and systemic) infections. During infections, these invasive and adherent pathogens hijack the actin filaments of their host cells and rearrange them into discrete actin-rich structures that promote bacterial adhesion (via pedestals), invasion (via membrane ruffles and endocytic cups), intracellular motility (via comet/rocket tails) and/or intercellular dissemination (via membrane protrusions and invaginations). We have previously shown that actin-rich structures generated by L. monocytogenes contain the host actin cross-linker α-actinin-4. Here we set out to examine α-actinin-4 during other key steps of the L. monocytogenes infectious cycle as well as characterize the subcellular distribution of α-actinin-4 during infections with other model actin-hijacking bacterial pathogens (S. flexneri, S. Typhimurium and EPEC). Although α-actinin-4 is absent at sites of initial L. monocytogenes invasion, we show that it is a new component of the membrane invaginations formed during secondary infections of neighboring host cells. Importantly, we reveal that α-actinin-4 also localizes to the major actin-rich structures generated during cell culture infections with S. flexneri (comet/rocket tails and membrane protrusions), S. Typhimurium (membrane ruffles) and EPEC (pedestals). Taken together, these findings suggest that α-actinin-4 is a host factor that is exploited by an assortment of actin-hijacking bacterial pathogens.
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Affiliation(s)
- Aaron S Dhanda
- Department of Biological Sciences, Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Diana Yang
- Department of Biological Sciences, Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Julian A Guttman
- Department of Biological Sciences, Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, British Columbia, Canada
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20
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Liu Y, Shen W, Sun Y, Lv N, Sun K, Hu L, Ye Y, Gao Y, Li J. Virulence-Related Gene Distribution Among Shigella Isolates in Anhui, China: The Association with Antimicrobial Resistance. Infect Drug Resist 2020; 13:3637-3647. [PMID: 33116683 PMCID: PMC7585282 DOI: 10.2147/idr.s274862] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 09/26/2020] [Indexed: 12/27/2022] Open
Abstract
Objective The aim of this study was to investigate the antimicrobial resistance profiles and distribution of virulence-related genes (VRGs) among Shigella isolates in Anhui, China, and to identify the correlation between the VRGs and antimicrobial resistance. Materials and Methods A total of 525 non-duplicate Shigella isolates (449 S. flexneri, 68 S. sonnei, 3 S. boydii, and 5 S. dysenteriae) were collected in Anhui Province, China between September 2011 and September 2015. The antimicrobial resistance of the strains was determined by the agar dilution method according to CLSI guidelines. The presence of 16 VRGs, including ipaH, ipaA-D, ial, virB, virF, set, sen, icsA, icsB, sigA, sat, pic, and sepA, was evaluated using PCR amplification and sequencing. Results Shigella flexneri was the most abundant (85.5%), followed by S. sonnei (13.0%). The proportion of males with S. flexneri was higher than that of females (57% vs 43%; P<0.0001). The most common resistance pattern was the combination of ampicillin, nalidixic acid, and tetracycline for S. flexneri (90.2%) and S. sonnei (94.1%). Resistance to ciprofloxacin and levofloxacin was more common among S. flexneri than among S. sonnei (49.7% vs.19.1%, P<0.0001; 30.5% vs 10.3%, P=0.001, respectively). All the isolates were positive for the ipaH gene, while the set, sat, pic, and sepA genes were not detected among the S. sonnei isolates. Except for sigA and sen, resistance to chloramphenicol and ciprofloxacin was more common among VRG-positive S. flexneri than among VRG-negative S. flexneri (P<0.05). Furthermore, resistance to ceftriaxone and ceftazidime was more frequently detected among sat- and set-positive S. flexneri than among sat- and set-negative S. flexneri (P<0.05). However, gentamicin resistance was more prevalent among VRG-negative (ial, virF, set, sat, pic, and sepA) S. flexneri than among VRG-positive S. flexneri (P<0.05). Conclusion Shigella flexneri remains the predominant species in Anhui, China, and the resistance to fluoroquinolones was more widespread among S. flexneri than among S. sonnei. Shigella flexneri strains harboring specific VRGs were associated with antimicrobial resistance. To the best of our knowledge, this is the first report of the correlation between the VRGs and antimicrobial resistance in Anhui, China.
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Affiliation(s)
- Yanyan Liu
- Department of Infectious Diseases, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, People's Republic of China.,Anhui Center for Surveillance of Bacterial Resistance, Hefei, Anhui, People's Republic of China.,Institute of Bacterial Resistance, Anhui Medical University, Hefei, Anhui, People's Republic of China
| | - Weihua Shen
- Department of Special Clinic, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, People's Republic of China
| | - Yating Sun
- Department of Infectious Diseases, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, People's Republic of China
| | - Na Lv
- Department of Infectious Diseases, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, People's Republic of China
| | - Kaili Sun
- Department of Infectious Diseases, The Chaohu Affiliated Hospital of Anhui Medical University, Hefei, Anhui, People's Republic of China
| | - Lifen Hu
- Department of Infectious Diseases, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, People's Republic of China
| | - Ying Ye
- Department of Infectious Diseases, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, People's Republic of China.,Anhui Center for Surveillance of Bacterial Resistance, Hefei, Anhui, People's Republic of China.,Institute of Bacterial Resistance, Anhui Medical University, Hefei, Anhui, People's Republic of China
| | - Yufeng Gao
- Department of Infectious Diseases, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, People's Republic of China.,Anhui Center for Surveillance of Bacterial Resistance, Hefei, Anhui, People's Republic of China.,Institute of Bacterial Resistance, Anhui Medical University, Hefei, Anhui, People's Republic of China
| | - Jiabin Li
- Department of Infectious Diseases, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, People's Republic of China.,Anhui Center for Surveillance of Bacterial Resistance, Hefei, Anhui, People's Republic of China.,Institute of Bacterial Resistance, Anhui Medical University, Hefei, Anhui, People's Republic of China.,Department of Infectious Diseases, The Chaohu Affiliated Hospital of Anhui Medical University, Hefei, Anhui, People's Republic of China
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21
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Desvaux M, Dalmasso G, Beyrouthy R, Barnich N, Delmas J, Bonnet R. Pathogenicity Factors of Genomic Islands in Intestinal and Extraintestinal Escherichia coli. Front Microbiol 2020; 11:2065. [PMID: 33101219 PMCID: PMC7545054 DOI: 10.3389/fmicb.2020.02065] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 08/05/2020] [Indexed: 12/20/2022] Open
Abstract
Escherichia coli is a versatile bacterial species that includes both harmless commensal strains and pathogenic strains found in the gastrointestinal tract in humans and warm-blooded animals. The growing amount of DNA sequence information generated in the era of "genomics" has helped to increase our understanding of the factors and mechanisms involved in the diversification of this bacterial species. The pathogenic side of E. coli that is afforded through horizontal transfers of genes encoding virulence factors enables this bacterium to become a highly diverse and adapted pathogen that is responsible for intestinal or extraintestinal diseases in humans and animals. Many of the accessory genes acquired by horizontal transfers form syntenic blocks and are recognized as genomic islands (GIs). These genomic regions contribute to the rapid evolution, diversification and adaptation of E. coli variants because they are frequently subject to rearrangements, excision and transfer, as well as to further acquisition of additional DNA. Here, we review a subgroup of GIs from E. coli termed pathogenicity islands (PAIs), a concept defined in the late 1980s by Jörg Hacker and colleagues in Werner Goebel's group at the University of Würzburg, Würzburg, Germany. As with other GIs, the PAIs comprise large genomic regions that differ from the rest of the genome by their G + C content, by their typical insertion within transfer RNA genes, and by their harboring of direct repeats (at their ends), integrase determinants, or other mobility loci. The hallmark of PAIs is their contribution to the emergence of virulent bacteria and to the development of intestinal and extraintestinal diseases. This review summarizes the current knowledge on the structure and functional features of PAIs, on PAI-encoded E. coli pathogenicity factors and on the role of PAIs in host-pathogen interactions.
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Affiliation(s)
- Mickaël Desvaux
- Université Clermont Auvergne, INRAE, MEDiS, Clermont-Ferrand, France
| | - Guillaume Dalmasso
- UMR Inserm 1071, USC-INRAE 2018, M2iSH, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Racha Beyrouthy
- UMR Inserm 1071, USC-INRAE 2018, M2iSH, Université Clermont Auvergne, Clermont-Ferrand, France
- Laboratoire de Bactériologie, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - Nicolas Barnich
- UMR Inserm 1071, USC-INRAE 2018, M2iSH, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Julien Delmas
- UMR Inserm 1071, USC-INRAE 2018, M2iSH, Université Clermont Auvergne, Clermont-Ferrand, France
- Laboratoire de Bactériologie, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - Richard Bonnet
- UMR Inserm 1071, USC-INRAE 2018, M2iSH, Université Clermont Auvergne, Clermont-Ferrand, France
- Laboratoire de Bactériologie, CHU Clermont-Ferrand, Clermont-Ferrand, France
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22
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Invasion of Epithelial Cells Is Correlated with Secretion of Biosurfactant via the Type 3 Secretion System (T3SS) of Shigella flexneri. J Pathog 2020; 2020:3062821. [PMID: 32802515 PMCID: PMC7411461 DOI: 10.1155/2020/3062821] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 06/30/2020] [Indexed: 11/17/2022] Open
Abstract
Biosurfactants are amphipathic molecules produced by many microorganisms, usually bacteria, fungi, and yeasts. They possess the property of reducing the tension of the membrane interfaces. No studies have been conducted on Shigella species showing the role of biosurfactant-like molecules (BLM) in pathogenicity. The aim of this study is to assess the ability of Shigella environmental and clinical strains to produce BLM and investigate the involvement of biosurfactants in pathogenicity. Our study has shown that BLM are secreted in the extracellular medium with EI24 ranging from 80% to 100%. The secretion is depending on the type III secretion system (T3SS). Moreover, our results have shown that S. flexneri, S. boydii, and S. sonnei are able to interact with hydrophobic areas with 17.64%, 21.42%, and 22.22% hydrophobicity, respectively. BLM secretion is totally prevented due to inhibition of T3SS by 100 mM benzoic and 1.5 mg/ml salicylic acids. P. aeruginosa harboring T3SS is able to produce 100% of BLM in the presence or in the absence of both T3SS inhibitors. The secreted BLM are extractable with an organic solvent such as chloroform, and this could entirely be considered a lipopeptide or polypeptide compound. Secretion of BLM allows some Shigella strains to induce multicellular phenomena like "swarming."
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23
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Whelan R, McVicker G, Leo JC. Staying out or Going in? The Interplay between Type 3 and Type 5 Secretion Systems in Adhesion and Invasion of Enterobacterial Pathogens. Int J Mol Sci 2020; 21:E4102. [PMID: 32521829 PMCID: PMC7312957 DOI: 10.3390/ijms21114102] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/03/2020] [Accepted: 06/05/2020] [Indexed: 12/12/2022] Open
Abstract
Enteric pathogens rely on a variety of toxins, adhesins and other virulence factors to cause infections. Some of the best studied pathogens belong to the Enterobacterales order; these include enteropathogenic and enterohemorrhagic Escherichia coli, Shigella spp., and the enteropathogenic Yersiniae. The pathogenesis of these organisms involves two different secretion systems, a type 3 secretion system (T3SS) and type 5 secretion systems (T5SSs). The T3SS forms a syringe-like structure spanning both bacterial membranes and the host cell plasma membrane that translocates toxic effector proteins into the cytoplasm of the host cell. T5SSs are also known as autotransporters, and they export part of their own polypeptide to the bacterial cell surface where it exerts its function, such as adhesion to host cell receptors. During infection with these enteropathogens, the T3SS and T5SS act in concert to bring about rearrangements of the host cell cytoskeleton, either to invade the cell, confer intracellular motility, evade phagocytosis or produce novel structures to shelter the bacteria. Thus, in these bacteria, not only the T3SS effectors but also T5SS proteins could be considered "cytoskeletoxins" that bring about profound alterations in host cell cytoskeletal dynamics and lead to pathogenic outcomes.
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Affiliation(s)
| | | | - Jack C. Leo
- Antimicrobial Resistance, Omics and Microbiota Group, Department of Biosciences, Nottingham Trent University, Nottingham NG1 4FQ, UK; (R.W.); (G.M.)
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24
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Kutsch M, Sistemich L, Lesser CF, Goldberg MB, Herrmann C, Coers J. Direct binding of polymeric GBP1 to LPS disrupts bacterial cell envelope functions. EMBO J 2020; 39:e104926. [PMID: 32510692 PMCID: PMC7327485 DOI: 10.15252/embj.2020104926] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 04/27/2020] [Accepted: 04/29/2020] [Indexed: 12/13/2022] Open
Abstract
In the outer membrane of gram‐negative bacteria, O‐antigen segments of lipopolysaccharide (LPS) form a chemomechanical barrier, whereas lipid A moieties anchor LPS molecules. Upon infection, human guanylate binding protein‐1 (hGBP1) colocalizes with intracellular gram‐negative bacterial pathogens, facilitates bacterial killing, promotes activation of the lipid A sensor caspase‐4, and blocks actin‐driven dissemination of the enteric pathogen Shigella. The underlying molecular mechanism for hGBP1's diverse antimicrobial functions is unknown. Here, we demonstrate that hGBP1 binds directly to LPS and induces “detergent‐like” LPS clustering through protein polymerization. Binding of polymerizing hGBP1 to the bacterial surface disrupts the O‐antigen barrier, thereby unmasking lipid A, eliciting caspase‐4 recruitment, enhancing antibacterial activity of polymyxin B, and blocking the function of the Shigella outer membrane actin motility factor IcsA. These findings characterize hGBP1 as an LPS‐binding surfactant that destabilizes the rigidity of the outer membrane to exert pleiotropic effects on the functionality of gram‐negative bacterial cell envelopes.
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Affiliation(s)
- Miriam Kutsch
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA
| | - Linda Sistemich
- Department of Physical Chemistry I, Ruhr-University Bochum, Bochum, Germany
| | - Cammie F Lesser
- Division of Infectious Diseases, Center for Bacterial Pathogenesis, Massachusetts General Hospital, Boston, MA, USA.,Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Marcia B Goldberg
- Division of Infectious Diseases, Center for Bacterial Pathogenesis, Massachusetts General Hospital, Boston, MA, USA.,Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Christian Herrmann
- Department of Physical Chemistry I, Ruhr-University Bochum, Bochum, Germany
| | - Jörn Coers
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA.,Department of Immunology, Duke University Medical Center, Durham, NC, USA
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25
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Abstract
The bacterial pathogen Shigella flexneri causes more than 250 million cases of bacillary dysentery (blood in stool) every year across the world. This human-specific disease is characterized by profuse bloody diarrhea, dramatic ulceration of the colonic epithelium and immune cell infiltration of the colonic tissue. A major challenge in understanding the mechanisms supporting bacillary dysentery is the reliance on animal models that do not fully recapitulate the symptoms observed in humans, including bloody diarrhea. Here we outline advances provided by a recently developed infant rabbit model of bacillary dysentery. The infant rabbit model defines bacillary dysentery as a critical combination of massive vascular lesions and dramatic epithelial fenestration due to intracellular infection and cell-to-cell spread, respectively. The infant rabbit model provides an unprecedented framework for understanding how the cell biology of Shigella flexneri infection relates to pathogenesis.
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Affiliation(s)
- Lauren K. Yum
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Hervé Agaisse
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA, USA,CONTACT Hervé Agaisse Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia22908, USA
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26
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Jiang L, Lee HW, Loo SCJ. Therapeutic lipid-coated hybrid nanoparticles against bacterial infections. RSC Adv 2020; 10:8497-8517. [PMID: 35497832 PMCID: PMC9050015 DOI: 10.1039/c9ra10921h] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 02/14/2020] [Indexed: 12/26/2022] Open
Abstract
One of the most important health concerns in society is the development of pathogen-causing nosocomial infections. Since the first discovery of antibiotics, bacterial infections have been highly treatable. However, with evolution and the nondiscretionary usage of antibiotics, pathogens have also found new ways to survive the onslaught of antibiotics by surviving intracellularly or through the formation of obstinate biofilms, and through these, the outcomes of regular antibiotic treatments may now be unsatisfactory. Lipid-coated hybrid nanoparticles (LCHNPs) are the next-generation core–shell structured nanodelivery system, where an inorganic or organic core, loaded with antimicrobials, is enveloped by lipid layers. This core–shell structure, with multifarious decorations, not only improves the loading capabilities of therapeutics but also has the potential to improve therapeutic delivery, especially for targeting biofilm-based and intracellular bacterial infections. Although there has been significant interest in the development of LCHNPs, they have yet to be widely exploited for bacterial infections. In this review, we will provide an overview on the latest development of LCHNPs and the various approaches in synthesizing this nano-delivery system. In addition, a discussion on future perspectives of LCHNPs, in combination with other novel anti-bacterial technologies, will be provided towards the end of this review. Lipid-coated hybrid nanoparticles are next-generation core–shell structured nanodelivery systems, which improve the loading capabilities of therapeutics and can improve therapeutic delivery, especially for targeting biofilm-based and intracellular bacterial infections.![]()
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Affiliation(s)
- Lai Jiang
- School of Materials Science & Engineering
- Nanyang Technological University
- Singapore
| | - Hiang Wee Lee
- School of Materials Science & Engineering
- Nanyang Technological University
- Singapore
| | - Say Chye Joachim Loo
- School of Materials Science & Engineering
- Nanyang Technological University
- Singapore
- Singapore Centre for Environmental Life Sciences Engineering
- Nanyang Technological University
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27
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A Novel Mouse Model of Enteric Vibrio parahaemolyticus Infection Reveals that the Type III Secretion System 2 Effector VopC Plays a Key Role in Tissue Invasion and Gastroenteritis. mBio 2019; 10:mBio.02608-19. [PMID: 31848276 PMCID: PMC6918077 DOI: 10.1128/mbio.02608-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The Gram-negative marine bacterium Vibrio parahaemolyticus is a common cause of infectious gastroenteritis due to the ingestion of contaminated seafood. Most virulent V. parahaemolyticus strains encode two type III secretion systems (T3SS1 and T3SS2); however, the roles they and their translocated effectors play in causing intestinal disease remain unclear. While studies have identified T3SS1 effectors as responsible for killing epithelial cells in culture, the T3SS2 effectors caused massive epithelial cell disruption in a rabbit ileal loop model. Additional models are thus needed to clarify the pathogen-host interactions that drive V. parahaemolyticus-associated gastroenteritis. Germfree mice were infected with a pathogenic clinical isolate of V. parahaemolyticus, RIMD2210633 (RIMD). The pathogen was found to adhere to as well as invade the cecal mucosa, accompanied by severe inflammation and dramatic mucosal damage, including widespread sloughing of infected epithelial cells. Mice infected with a V. parahaemolyticus strain lacking the T3SS1 (POR2) also developed severe pathology, similar to that seen with RIMD. In contrast, the ΔT3SS2 strain (POR3) appeared unable to invade the intestinal mucosa or cause any mucosal pathology. Confirming a role for TS332 effectors, a strain expressing the T3SS2 but lacking VopC (POR2ΔvopC), a T3SS2 effector implicated in epithelial cell invasion in culture, was strongly attenuated in invading the intestinal mucosa and in causing gastroenteritis, although infection with this mutant resulted in more pathology than the ΔT3SS2 strain. We thus present an experimental system that enables further characterization of T3SS effectors as well as the corresponding host inflammatory response involved in the gastroenteritis caused by invasive V. parahaemolyticus IMPORTANCE Vibrio parahaemolyticus causes severe gastroenteritis following consumption of contaminated seafood. Global warming has allowed this pathogen to spread worldwide, contributing to recent outbreaks. Clinical isolates are known to harbor an array of virulence factors, including T3SS1 and T3SS2; however, the precise role these systems play in intestinal disease remains unclear. There is an urgent need to improve our understanding of how V. parahaemolyticus infects hosts and causes disease. We present a novel mouse model for this facultative intracellular pathogen and observe that the T3SS2 is essential to pathogenicity. Moreover, we show that the T3SS2 effector VopC, previously shown to be a Rac and Cdc42 deamidase that facilitates bacterial uptake by nonphagocytic cells, also plays a key role in the ability of V. parahaemolyticus to invade the intestinal mucosa and cause gastroenteritis. This experimental model thus provides a valuable tool for future elucidation of virulence mechanisms used by this facultative intracellular pathogen during in vivo infection.
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28
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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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29
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Michard C, Yum LK, Agaisse H. WIPF2 promotesShigella flexneriactin‐based motility and cell‐to‐cell spread. Cell Microbiol 2019; 21:e13098. [DOI: 10.1111/cmi.13098] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 08/08/2019] [Accepted: 08/10/2019] [Indexed: 11/28/2022]
Affiliation(s)
- Céline Michard
- Department of Microbiology, Immunology, and Cancer BiologyUniversity of Virginia Charlottesville Virginia
| | - Lauren K. Yum
- Department of Microbiology, Immunology, and Cancer BiologyUniversity of Virginia Charlottesville Virginia
| | - Hervé Agaisse
- Department of Microbiology, Immunology, and Cancer BiologyUniversity of Virginia Charlottesville Virginia
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30
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The Autotransporter IcsA Promotes Shigella flexneri Biofilm Formation in the Presence of Bile Salts. Infect Immun 2019; 87:IAI.00861-18. [PMID: 30988059 DOI: 10.1128/iai.00861-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 04/09/2019] [Indexed: 12/25/2022] Open
Abstract
Shigella flexneri is an intracellular bacterial pathogen that invades epithelial cells in the colonic mucosa, leading to bloody diarrhea. A previous study showed that S. flexneri forms biofilms in the presence of bile salts, through an unknown mechanism. Here, we investigated the potential role of adhesin-like autotransporter proteins in S. flexneri biofilm formation. BLAST search analysis revealed that the S. flexneri 2457T genome harbors 4 genes, S1242, S1289, S2406, and icsA, encoding adhesin-like autotransporter proteins. Deletion mutants of the S1242, S1289, S2406 and icsA genes were generated and tested for biofilm formation. Phenotypic analysis of the mutant strains revealed that disruption of icsA abolished bile salt-induced biofilm formation. IcsA is an outer membrane protein secreted at the bacterial pole that is required for S. flexneri actin-based motility during intracellular infection. In extracellular biofilms, IcsA was also secreted at the bacterial pole and mediated bacterial cell-cell contacts and aggregative growth in the presence of bile salts. Dissecting individual roles of bile salts showed that deoxycholate is a robust biofilm inducer compared to cholate. The release of the extracellular domain of IcsA through IcsP-mediated cleavage was greater in the presence of cholate, suggesting that the robustness of biofilm formation was inversely correlated with IcsA processing. Accordingly, deletion of icsP abrogated IcsA processing in biofilms and enhanced biofilm formation.
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31
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32
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De Souza Santos M, Orth K. The Role of the Type III Secretion System in the Intracellular Lifestyle of Enteric Pathogens. Microbiol Spectr 2019; 7:10.1128/microbiolspec.bai-0008-2019. [PMID: 31152523 PMCID: PMC11026088 DOI: 10.1128/microbiolspec.bai-0008-2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Indexed: 11/20/2022] Open
Abstract
Several pathogens have evolved to infect host cells from within, which requires subversion of many host intracellular processes. In the case of Gram-negative pathogenic bacteria, adaptation to an intracellular life cycle relies largely on the activity of type III secretion systems (T3SSs), an apparatus used to deliver effector proteins into the host cell, from where these effectors regulate important cellular functions such as vesicular trafficking, cytoskeleton reorganization, and the innate immune response. Each bacterium is equipped with a unique suite of these T3SS effectors, which aid in the development of an individual intracellular lifestyle for their respective pathogens. Some bacteria adapt to reside and propagate within a customized vacuole, while others establish a replicative niche in the host cytosol. In this article, we review the mechanisms by which T3SS effectors contribute to these different lifestyles. To illustrate the formation of a vacuolar and a cytosolic lifestyle, we discuss the intracellular habitats of the enteric pathogens Salmonella enterica serovar Typhimurium and Shigella flexneri, respectively. These represent well-characterized systems that function as informative models to contribute to our understanding of T3SS-dependent subversion of intracellular processes. Additionally, we present Vibrio parahaemolyticus, another enteric Gram-negative pathogen, as an emerging model for future studies of the cytosolic lifestyle.
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Affiliation(s)
- Marcela De Souza Santos
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Kim Orth
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Department of Biochemistry and
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390
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33
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Yum LK, Byndloss MX, Feldman SH, Agaisse H. Critical role of bacterial dissemination in an infant rabbit model of bacillary dysentery. Nat Commun 2019; 10:1826. [PMID: 31015451 PMCID: PMC6478941 DOI: 10.1038/s41467-019-09808-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 03/28/2019] [Indexed: 11/09/2022] Open
Abstract
The bacterial pathogen Shigella flexneri causes 270 million cases of bacillary dysentery (blood in stool) worldwide every year, resulting in more than 200,000 deaths. A major challenge in combating bacillary dysentery is the lack of a small-animal model that recapitulates the symptoms observed in infected individuals, including bloody diarrhea. Here, we show that similar to humans, infant rabbits infected with S. flexneri experience severe inflammation, massive ulceration of the colonic mucosa, and bloody diarrhea. T3SS-dependent invasion of epithelial cells is necessary and sufficient for mediating immune cell infiltration and vascular lesions. However, massive ulceration of the colonic mucosa, bloody diarrhea, and dramatic weight loss are strictly contingent on the ability of the bacteria to spread from cell to cell. The infant rabbit model features bacterial dissemination as a critical determinant of S. flexneri pathogenesis and provides a unique small-animal model for research and development of therapeutic interventions.
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Affiliation(s)
- Lauren K Yum
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Mariana X Byndloss
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Sanford H Feldman
- Center for Comparative Medicine, University of Virginia, Charlottesville, VA, USA
| | - Hervé Agaisse
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA.
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Abstract
ABSTRACT
Shigella
is a genus of Gram-negative enteropathogens that have long been, and continue to be, an important public health concern worldwide. Over the past several decades,
Shigella
spp. have also served as model pathogens in the study of bacterial pathogenesis, and
Shigella flexneri
has become one of the best-studied pathogens on a molecular, cellular, and tissue level. In the arms race between
Shigella
and the host immune system,
Shigella
has developed highly sophisticated mechanisms to subvert host cell processes in order to promote infection, escape immune detection, and prevent bacterial clearance. Here, we give an overview of
Shigella
pathogenesis while highlighting innovative techniques and methods whose application has significantly advanced our understanding of
Shigella
pathogenesis in recent years.
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35
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Spatial, Temporal, and Functional Assessment of LC3-Dependent Autophagy in Shigella flexneri Dissemination. Infect Immun 2018; 86:IAI.00134-18. [PMID: 29844234 DOI: 10.1128/iai.00134-18] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 05/22/2018] [Indexed: 12/21/2022] Open
Abstract
Shigella flexneri disseminates within the colonic mucosa by displaying actin-based motility in the cytosol of epithelial cells. Motile bacteria form membrane protrusions that project into adjacent cells and resolve into double-membrane vacuoles (DMVs) from which the bacteria escape, thereby achieving cell-to-cell spread. During dissemination, S. flexneri is targeted by LC3-dependent autophagy, a host cell defense mechanism against intracellular pathogens. The S. flexneri type III secretion system effector protein IcsB was initially proposed to counteract the recruitment of the LC3-dependent autophagy machinery to cytosolic bacteria. However, a recent study proposed that LC3 was recruited to bacteria in DMVs formed during cell-to-cell spread. To resolve the controversy and clarify the role of autophagy in S. flexneri infection, we tracked dissemination using live confocal microscopy and determined the spatial and temporal recruitment of LC3 to bacteria. This approach demonstrated that (i) LC3 was exclusively recruited to wild-type or icsB bacteria located in DMVs and (ii) the icsB mutant was defective in cell-to-cell spread due to failure to escape LC3-positive as well as LC3-negative DMVs. Failure of S. flexneri to escape DMVs correlated with late LC3 recruitment, suggesting that LC3 recruitment is the consequence and not the cause of DMV escape failure. Inhibition of autophagy had no positive impact on the spreading of wild-type or icsB mutant bacteria. Our results unambiguously demonstrate that IcsB is required for DMV escape during cell-to-cell spread, regardless of LC3 recruitment, and do not support the previously proposed notion that autophagy counters S. flexneri dissemination.
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36
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Case HB, Dickenson NE. MxiN Differentially Regulates Monomeric and Oligomeric Species of the Shigella Type Three Secretion System ATPase Spa47. Biochemistry 2018; 57:2266-2277. [PMID: 29595954 DOI: 10.1021/acs.biochem.8b00070] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Shigella rely entirely on the action of a single type three secretion system (T3SS) to support cellular invasion of colonic epithelial cells and to circumvent host immune responses. The ATPase Spa47 resides at the base of the Shigella needle-like type three secretion apparatus (T3SA), supporting protein secretion through the apparatus and providing a likely means for native virulence regulation by Shigella and a much needed target for non-antibiotic therapeutics to treat Shigella infections. Here, we show that MxiN is a differential regulator of Spa47 and that its regulatory impact is determined by the oligomeric state of the Spa47 ATPase, with which it interacts. In vitro and in vivo characterization shows that interaction of MxiN with Spa47 requires the six N-terminal residues of Spa47 that are also necessary for stable Spa47 oligomer formation and activation. This interaction with MxiN negatively influences the activity of Spa47 oligomers while upregulating the ATPase activity of monomeric Spa47. Detailed kinetic analyses of monomeric and oligomeric Spa47 in the presence and absence of MxiN uncover additional mechanistic insights into the regulation of Spa47 by MxiN, suggesting that the MxiN/Spa47 species resulting from interaction with monomeric and oligomeric Spa47 are functionally distinct and that both could be involved in Shigella T3SS regulation. Uncovering regulation of Spa47 by MxiN addresses an important gap in the current understanding of how Shigella controls T3SA activity and provides the first description of differential T3SS ATPase regulation by a native T3SS protein.
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Affiliation(s)
- Heather B Case
- Department of Chemistry and Biochemistry , Utah State University , Logan , Utah 84322 , United States
| | - Nicholas E Dickenson
- Department of Chemistry and Biochemistry , Utah State University , Logan , Utah 84322 , United States
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37
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Abstract
Cardiolipin, an anionic phospholipid that resides at the poles of the inner and outer membranes, is synthesized primarily by the putative cardiolipin synthase ClsA in Shigella flexneri. An S. flexneri clsA mutant had no cardiolipin detected within its membrane, grew normally in vitro, and invaded cultured epithelial cells, but it failed to form plaques in epithelial cell monolayers, indicating that cardiolipin is required for virulence. The clsA mutant was initially motile within the host cell cytoplasm but formed filaments and lost motility during replication and failed to spread efficiently to neighboring cells. Mutation of pbgA, which encodes the transporter for cardiolipin from the inner membrane to the outer membrane, also resulted in loss of plaque formation. The S. flexneri pbgA mutant had normal levels of cardiolipin in the inner membrane, but no cardiolipin was detected in the outer membrane. The pbgA mutant invaded and replicated normally within cultured epithelial cells but failed to localize the actin polymerization protein IcsA properly on the bacterial surface and was unable to spread to neighboring cells. The clsA mutant, but not the pbgA mutant, had increased phosphatidylglycerol in the outer membrane. This appeared to compensate partially for the loss of cardiolipin in the outer membrane, allowing some IcsA localization in the outer membrane of the clsA mutant. We propose a dual function for cardiolipin in S. flexneri pathogenesis. In the inner membrane, cardiolipin is essential for proper cell division during intracellular growth. In the outer membrane, cardiolipin facilitates proper presentation of IcsA on the bacterial surface. The human pathogen Shigella flexneri causes bacterial dysentery by invading colonic epithelial cells, rapidly multiplying within their cytoplasm, and then spreading intercellularly to neighboring cells. Worldwide, Shigella spp. infect hundreds of millions of people annually, with fatality rates up to 15%. Antibiotic treatment of Shigella infections is compromised by increasing antibiotic resistance, and there is no approved vaccine to prevent future infections. This has created a growing need to understand Shigella pathogenesis and identify new targets for antimicrobial therapeutics. Here we show a previously unknown role of phospholipids in S. flexneri pathogenesis. We demonstrate that cardiolipin is required in the outer membrane for proper surface localization of IcsA and in the inner membrane for cell division during growth in the host cell cytoplasm.
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38
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Giangrossi M, Giuliodori AM, Tran CN, Amici A, Marchini C, Falconi M. VirF Relieves the Transcriptional Attenuation of the Virulence Gene icsA of Shigella flexneri Affecting the icsA mRNA-RnaG Complex Formation. Front Microbiol 2017; 8:650. [PMID: 28458662 PMCID: PMC5394118 DOI: 10.3389/fmicb.2017.00650] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 03/29/2017] [Indexed: 12/31/2022] Open
Abstract
VirF is the master activator of virulence genes of Shigella and its expression is required for the invasion of the human intestinal mucosa by pathogenic bacteria. VirF was shown to directly activate the transcription of virB and icsA, which encode two essential proteins involved in the pathogenicity process, by binding their promoter regions. In this study, we demonstrate by band shift, enzymatic probing and cross-linking experiments that VirF, in addition to DNA, can also bind the icsA transcript and RnaG, an antisense non-coding small RNA that promotes the premature termination of icsA mRNA through a transcriptional attenuation mechanism. Furthermore, we show that VirF binds in vitro also other species of RNAs, although with lower specificity. The existence of VirF–RnaG and VirF-icsA mRNA complexes is confirmed in a pulldown assay carried out under experimental conditions that very close reproduce the in vivo conditions and that allows immobilized VirF to “fish” out RnaG and icsA mRNA from a total RNA extract. The VirF binding sites identified on both icsA mRNA and RnaG contain a 13 nucleotides stretch (5′-UUUUaGYcUuUau-3′) that is the RNA-converted consensus sequence previously proposed for the VirF–DNA interaction. Band-shift assays with a synthetic RNA molecule whose sequence perfectly matches the consensus indicate that this signature plays a key role also in the VirF–RNA interaction, in particular when exposed in a stem–loop structure. To further explore the icsA-RnaG-VirF regulatory system, we developed an in vitro test (RNA–RNA Pairing Assay) in which pairing between icsA mRNA and synthetic RNAs that reproduce the individual stem–loop motifs of RnaG, was analyzed in the presence of VirF. This assay shows that this protein can prevent the formation of the kissing complex, defined as the initial nucleation points for RNA heteroduplex formation, between RnaG and icsA mRNA. Consistently, VirF alleviates the RnaG-mediated repression of icsA transcription in vitro. Therefore VirF, by hindering the icsA transcript-RnaG interaction, exhibits an activity opposed to that usually displayed by proteins, which generally assist the RNA–RNA interaction; this quite uncommon and new function and the regulatory implications of VirF as a potential RNA-binding protein are discussed.
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Affiliation(s)
- Mara Giangrossi
- School of Bioscience and Veterinary Medicine, University of CamerinoCamerino, Italy
| | - Anna M Giuliodori
- School of Bioscience and Veterinary Medicine, University of CamerinoCamerino, Italy
| | - Chi N Tran
- Food Science Department, Can Tho Technical - Economic CollegeCan Tho, Vietnam
| | - Augusto Amici
- School of Bioscience and Veterinary Medicine, University of CamerinoCamerino, Italy
| | - Cristina Marchini
- School of Bioscience and Veterinary Medicine, University of CamerinoCamerino, Italy
| | - Maurizio Falconi
- School of Bioscience and Veterinary Medicine, University of CamerinoCamerino, Italy
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39
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Wallace N, Zani A, Abrams E, Sun Y. The Impact of Oxygen on Bacterial Enteric Pathogens. ADVANCES IN APPLIED MICROBIOLOGY 2016; 95:179-204. [PMID: 27261784 DOI: 10.1016/bs.aambs.2016.04.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Bacterial enteric pathogens are responsible for a tremendous amount of foodborne illnesses every year through the consumption of contaminated food products. During their transit from contaminated food sources to the host gastrointestinal tract, these pathogens are exposed and must adapt to fluctuating oxygen levels to successfully colonize the host and cause diseases. However, the majority of enteric infection research has been conducted under aerobic conditions. To raise awareness of the importance in understanding the impact of oxygen, or lack of oxygen, on enteric pathogenesis, we describe in this review the metabolic and physiological responses of nine bacterial enteric pathogens exposed to environments with different oxygen levels. We further discuss the effects of oxygen levels on virulence regulation to establish potential connections between metabolic adaptations and bacterial pathogenesis. While not providing an exhaustive list of all bacterial pathogens, we highlight key differences and similarities among nine facultative anaerobic and microaerobic pathogens in this review to argue for a more in-depth understanding of the diverse impact oxygen levels have on enteric pathogenesis.
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Affiliation(s)
- N Wallace
- University of Dayton, Dayton, OH, United States
| | - A Zani
- University of Dayton, Dayton, OH, United States
| | - E Abrams
- University of Dayton, Dayton, OH, United States
| | - Y Sun
- University of Dayton, Dayton, OH, United States
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