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Yin H, Zheng J, He Q, Zhang X, Li X, Ma Y, Liang X, Gao J, Kocsis BL, Li Z, Liu X, Alto NM, Li L, Zhang H. Insights into the GSDMB-mediated cellular lysis and its targeting by IpaH7.8. Nat Commun 2023; 14:61. [PMID: 36599845 PMCID: PMC9813358 DOI: 10.1038/s41467-022-35725-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 12/21/2022] [Indexed: 01/06/2023] Open
Abstract
The multifunctional GSDMB protein is an important molecule in human immunity. The pyroptotic and bactericidal activity of GSDMB is a host response to infection by the bacterial pathogen Shigella flexneri, which employs the virulence effector IpaH7.8 to ubiquitinate and target GSDMB for proteasome-dependent degradation. Furthermore, IpaH7.8 selectively targets human but not mouse GSDMD, suggesting a non-canonical mechanism of substrate selection. Here, we report the crystal structure of GSDMB in complex with IpaH7.8. Together with biochemical and functional studies, we identify the potential membrane engagement sites of GSDMB, revealing general and unique features of gasdermin proteins in membrane recognition. We further illuminate how IpaH7.8 interacts with GSDMB, and delineate the mechanism by which IpaH7.8 ubiquitinates and suppresses GSDMB. Notably, guided by our structural model, we demonstrate that two residues in the α1-α2 loop make the mouse GSDMD invulnerable to IpaH7.8-mediated degradation. These findings provide insights into the versatile functions of GSDMB, which could open new avenues for therapeutic interventions for diseases, including cancers and bacterial infections.
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Affiliation(s)
- Hang Yin
- The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Haihe Laboratory of Cell Ecosystem, Tianjin Institute of Immunology, Department of Pharmacology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, 430062, Wuhan, China
| | - Jian Zheng
- The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Haihe Laboratory of Cell Ecosystem, Tianjin Institute of Immunology, Department of Pharmacology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
- Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
| | - Qiuqiu He
- The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Haihe Laboratory of Cell Ecosystem, Tianjin Institute of Immunology, Department of Pharmacology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
| | - Xuan Zhang
- Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
| | - Xuzichao Li
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
| | - Yongjian Ma
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
| | - Xiao Liang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
| | - Jiaqi Gao
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
| | - Benjamin L Kocsis
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Zhuang Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, 430062, Wuhan, China
| | - Xiang Liu
- State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Center for Cell Responses, College of Life Sciences, Nankai University, 300071, Tianjin, China
| | - Neal M Alto
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Long Li
- The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Haihe Laboratory of Cell Ecosystem, Tianjin Institute of Immunology, Department of Pharmacology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China.
- Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China.
| | - Heng Zhang
- The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Haihe Laboratory of Cell Ecosystem, Tianjin Institute of Immunology, Department of Pharmacology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China.
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China.
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Maculins T, Verschueren E, Hinkle T, Choi M, Chang P, Chalouni C, Rao S, Kwon Y, Lim J, Katakam AK, Kunz RC, Erickson BK, Huang T, Tsai TH, Vitek O, Reichelt M, Senbabaoglu Y, Mckenzie B, Rohde JR, Dikic I, Kirkpatrick DS, Murthy A. Multiplexed proteomics of autophagy-deficient murine macrophages reveals enhanced antimicrobial immunity via the oxidative stress response. eLife 2021; 10:e62320. [PMID: 34085925 PMCID: PMC8177894 DOI: 10.7554/elife.62320] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 05/12/2021] [Indexed: 12/11/2022] Open
Abstract
Defective autophagy is strongly associated with chronic inflammation. Loss-of-function of the core autophagy gene Atg16l1 increases risk for Crohn's disease in part by enhancing innate immunity through myeloid cells such as macrophages. However, autophagy is also recognized as a mechanism for clearance of certain intracellular pathogens. These divergent observations prompted a re-evaluation of ATG16L1 in innate antimicrobial immunity. In this study, we found that loss of Atg16l1 in myeloid cells enhanced the killing of virulent Shigella flexneri (S.flexneri), a clinically relevant enteric bacterium that resides within the cytosol by escaping from membrane-bound compartments. Quantitative multiplexed proteomics of murine bone marrow-derived macrophages revealed that ATG16L1 deficiency significantly upregulated proteins involved in the glutathione-mediated antioxidant response to compensate for elevated oxidative stress, which simultaneously promoted S.flexneri killing. Consistent with this, myeloid-specific deletion of Atg16l1 in mice accelerated bacterial clearance in vitro and in vivo. Pharmacological induction of oxidative stress through suppression of cysteine import enhanced microbial clearance by macrophages. Conversely, antioxidant treatment of macrophages permitted S.flexneri proliferation. These findings demonstrate that control of oxidative stress by ATG16L1 and autophagy regulates antimicrobial immunity against intracellular pathogens.
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Affiliation(s)
- Timurs Maculins
- Department of Cancer Immunology, GenentechSouth San FranciscoUnited States
- Institute of Biochemistry II, Goethe UniversityFrankfurt am MainGermany
| | - Erik Verschueren
- Department of Microchemistry, Proteomics and Lipidomics, GenentechSouth San FranciscoUnited States
| | - Trent Hinkle
- Department of Microchemistry, Proteomics and Lipidomics, GenentechSouth San FranciscoUnited States
| | - Meena Choi
- Department of Microchemistry, Proteomics and Lipidomics, GenentechSouth San FranciscoUnited States
- Khoury College of Computer Sciences, Northeastern UniversityBostonUnited States
| | - Patrick Chang
- Department of Pathology, GenentechSouth San FranciscoUnited States
| | - Cecile Chalouni
- Department of Pathology, GenentechSouth San FranciscoUnited States
| | - Shilpa Rao
- Department of Oncology Bioinformatics, GenentechSouth San FranciscoUnited States
| | - Youngsu Kwon
- Department of Translational Immunology, GenentechSouth San FranciscoUnited States
| | - Junghyun Lim
- Department of Cancer Immunology, GenentechSouth San FranciscoUnited States
| | | | | | | | - Ting Huang
- Khoury College of Computer Sciences, Northeastern UniversityBostonUnited States
| | - Tsung-Heng Tsai
- Khoury College of Computer Sciences, Northeastern UniversityBostonUnited States
- Department of Mathematical Sciences, Kent State UniversityKentUnited States
| | - Olga Vitek
- Khoury College of Computer Sciences, Northeastern UniversityBostonUnited States
| | - Mike Reichelt
- Department of Pathology, GenentechSouth San FranciscoUnited States
| | - Yasin Senbabaoglu
- Department of Oncology Bioinformatics, GenentechSouth San FranciscoUnited States
| | - Brent Mckenzie
- Department of Translational Immunology, GenentechSouth San FranciscoUnited States
| | - John R Rohde
- Department of Microbiology and Immunology, Dalhousie UniversityHalifaxCanada
| | - Ivan Dikic
- Institute of Biochemistry II, Goethe UniversityFrankfurt am MainGermany
- Department of Infectious Diseases, GenentechSouth San FranciscoUnited States
| | | | - Aditya Murthy
- Interline TherapeuticsSouth San FranciscoUnited States
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3
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Kühn S, Bergqvist J, Gil M, Valenzuela C, Barrio L, Lebreton S, Zurzolo C, Enninga J. Actin Assembly around the Shigella-Containing Vacuole Promotes Successful Infection. Cell Rep 2021; 31:107638. [PMID: 32402280 PMCID: PMC7225751 DOI: 10.1016/j.celrep.2020.107638] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 03/10/2020] [Accepted: 04/21/2020] [Indexed: 12/13/2022] Open
Abstract
The enteroinvasive bacterium Shigella flexneri forces its uptake into non-phagocytic host cells through the translocation of T3SS effectors that subvert the actin cytoskeleton. Here, we report de novo actin polymerization after cellular entry around the bacterium-containing vacuole (BCV) leading to the formation of a dynamic actin cocoon. This cocoon is thicker than any described cellular actin structure and functions as a gatekeeper for the cytosolic access of the pathogen. Host CDC42, TOCA-1, N-WASP, WIP, the Arp2/3 complex, cortactin, coronin, and cofilin are recruited to the actin cocoon. They are subverted by T3SS effectors, such as IpgD, IpgB1, and IcsB. IcsB immobilizes components of the actin polymerization machinery at the BCV dependent on its fatty acyltransferase activity. This represents a unique microbial subversion strategy through localized entrapment of host actin regulators causing massive actin assembly. We propose that the cocoon promotes subsequent invasion steps for successful Shigella infection. A thick actin cocoon forms de novo around the Shigella-containing vacuole upon entry The effector IcsB entraps host actin regulators at the vacuole by lipidation Cdc42, N-WASP, and the Arp2/3 complex are major actin cocoon regulators Cocoon formation promotes subsequent Shigella niche formation and dissemination
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Affiliation(s)
- Sonja Kühn
- Institut Pasteur, Department of Cell Biology and Infection, Dynamics of Host-Pathogen Interactions Unit, 25 Rue du Dr. Roux, 75015 Paris, France; CNRS UMR3691, 25 Rue du Dr. Roux, 75015 Paris, France
| | - John Bergqvist
- Institut Pasteur, Department of Cell Biology and Infection, Dynamics of Host-Pathogen Interactions Unit, 25 Rue du Dr. Roux, 75015 Paris, France; CNRS UMR3691, 25 Rue du Dr. Roux, 75015 Paris, France
| | - Magdalena Gil
- Institut Pasteur, Department of Cell Biology and Infection, Dynamics of Host-Pathogen Interactions Unit, 25 Rue du Dr. Roux, 75015 Paris, France; CNRS UMR3691, 25 Rue du Dr. Roux, 75015 Paris, France
| | - Camila Valenzuela
- Institut Pasteur, Department of Cell Biology and Infection, Dynamics of Host-Pathogen Interactions Unit, 25 Rue du Dr. Roux, 75015 Paris, France; CNRS UMR3691, 25 Rue du Dr. Roux, 75015 Paris, France
| | - Laura Barrio
- Institut Pasteur, Department of Cell Biology and Infection, Dynamics of Host-Pathogen Interactions Unit, 25 Rue du Dr. Roux, 75015 Paris, France; CNRS UMR3691, 25 Rue du Dr. Roux, 75015 Paris, France
| | - Stéphanie Lebreton
- Institut Pasteur, Department of Cell Biology and Infection, Membrane Trafficking and Pathogenesis Unit, 28 Rue du Dr. Roux, 75015 Paris, France
| | - Chiara Zurzolo
- Institut Pasteur, Department of Cell Biology and Infection, Membrane Trafficking and Pathogenesis Unit, 28 Rue du Dr. Roux, 75015 Paris, France
| | - Jost Enninga
- Institut Pasteur, Department of Cell Biology and Infection, Dynamics of Host-Pathogen Interactions Unit, 25 Rue du Dr. Roux, 75015 Paris, France; CNRS UMR3691, 25 Rue du Dr. Roux, 75015 Paris, France.
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Nisa I, Qasim M, Driessen A, Nijland J, Adnan F, Shuja MN, Rahman H. Virulence profiling of Shigella flexneri and emergence of serotype 2b as a highly virulent shigellosis causing strain in Pakistan. Infect Genet Evol 2021; 93:104922. [PMID: 34000445 DOI: 10.1016/j.meegid.2021.104922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 03/02/2021] [Accepted: 05/13/2021] [Indexed: 11/20/2022]
Abstract
Bacillary diarrhea caused by Shigella flexneri is mediated by various virulence factors which make it the leading agent of diarrhea in developing countries. Previously, a high prevalence of S. flexneri, associated with diarrhea has been reported in Pakistan but no data is available on their virulence profile. The present study reports for the first time analysis of various virulence factors among S. flexneri serotypes isolated from clinical (diarrheal stool) and non-clinical (retail raw foods and drinking water) sources. A total of 199 S. flexneri (clinical: 155, raw foods: 22, water: 22) belonging to various serotypes were subjected to virulence genes detection and virulence profiling. The most frequent virulence gene was found to be ipaH (100%), followed by sat (98%), ial (71.3%), set1B (65.8%) and set1A (38.7%). A high level of virulence was detected in serotype 2b as compared to other serotypes as 32.3% of all serotype 2b have the entire set of five virulence genes including ipaH (100%), ial (100%), sat (37.7%), set1A (89.3%), and set1B (100%). Seven different virulence gene profiles (V1 - V7) were detected and the most frequently observed to be V1 (ipaH+, ial+, sat+, set1A+, set1B+) followed by V3 (ipaH+, ial+, sat+, set1B+). The predominant virulence gene pattern in serotype 2b isolated from clinical and non-clinical samples were V1 and V3. Furthermore, about 32% strains belonging to serotype 2b contain the complete set of five virulence genes isolated from patients with high disease severity. In conclusion, the current finding revealed for the first times that serotype 2b was the most virulent strains in both clinical and non-clinical samples in Pakistan. In addition, the virulence of serotype 2b was well correlated with high disease severity.
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Affiliation(s)
- Iqbal Nisa
- Department of Microbiology, Kohat University of Science and Technology, Kohat 26000, Pakistan
| | - Muhammad Qasim
- Department of Microbiology, Kohat University of Science and Technology, Kohat 26000, Pakistan.
| | - Arnold Driessen
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, Rijksuniversiteit Groningen Faculty of Science and Engineering, the Netherlands
| | - Jeroen Nijland
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, Rijksuniversiteit Groningen Faculty of Science and Engineering, the Netherlands
| | - Fazal Adnan
- Atta Ur Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology, Islamabad, Pakistan
| | - Malik Nawaz Shuja
- Department of Microbiology, Kohat University of Science and Technology, Kohat 26000, Pakistan
| | - Hazir Rahman
- Department of Microbiology, Abdul Wali Khan University, Mardan, Pakistan
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Shabani NRM, Mokhtar M, Leow CH, Lean QY, Chuah C, Singh KKB, Leow CY. Differential expression of cytokine genes in THP-1-derived macrophages infected with mild and virulence strains of Shigella flexneri 2a. Infect Genet Evol 2020; 85:104532. [PMID: 32911076 DOI: 10.1016/j.meegid.2020.104532] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/25/2020] [Accepted: 09/02/2020] [Indexed: 11/19/2022]
Abstract
Shigella is an intracellular bacterial pathogen that causes bacterial dysentery called shigellosis. The assessment of pro- and anti-inflammatory mediators produced by immune cells against this bacteria are vital in identifying the effectiveness of the immune reaction in protecting the host. In Malaysia, Shigella is ranked as the third most common bacteria causing diarrheal disease among children below 5 years old. In the present study, we aim to examine the differential cytokine gene expressions of macrophages in response to two types of clinical strains of Shigella flexneri 2a (S. flexneri 2a) isolated from patients admitted in Hospital Universiti Sains Malaysia, Kelantan, Malaysia. THP-1-derived macrophages, as the model of human macrophages, were infected separately with S. flexneri 2a mild (SH062) and virulence (SH057) strains for 6, 12, and 24 h, respectively. The gene expression level of inflammatory mediators was identified using real-time quantitative polymerase chain reaction (RT-qPCR). The production of nitric oxide (NO) by the macrophages was measured by using a commercialized NO assay kit. The ability of macrophages to kill the intracellular bacteria was assessed by intracellular killing assay. Induction of tumor necrosis factor-alpha (TNFα), interleukin (IL)-1β, IL-6, IL-12, inducible NO synthase (iNOS), and NO, confirmed the pro-inflammatory reaction of the THP-1-derived macrophages in response to S. flexneri 2a, especially against the SH507 strain. The SH057 also induced a marked increase in the expression levels of the anti-inflammatory cytokine mRNAs at 12 h and 24 h post-infection. In the intracellular killing assay, both strains showed less viable, indicating the generation of pro-inflammatory cytokines in the presence of iNOS and NO was crucial in the stimulation of macrophages for the host defense against shigellosis. Transcription analysis of THP-1-derived macrophages in this study identifies differentially expressed cytokine genes that correlated with the virulence factor of S. flexneri 2a.
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Affiliation(s)
- Nor Raihan Mohammad Shabani
- Institute for Research in Molecular Medicine, Universiti Sains Malaysia, Health Campus, 16150 Kubang Kerian, Kelantan, Malaysia; Faculty of Health Sciences, Universiti Teknologi MARA, Cawangan Pulau Pinang, Kampus Bertam, 13200 Kepala Batas, Penang, Malaysia
| | - Munirah Mokhtar
- Institute for Research in Molecular Medicine, Universiti Sains Malaysia, Health Campus, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Chiuan Herng Leow
- Institute for Research in Molecular Medicine, Universiti Sains Malaysia, 11800 Gelugor, Penang, Malaysia
| | - Qi Ying Lean
- Faculty of Pharmacy, Universiti Teknologi MARA, Cawangan Pulau Pinang, Kampus Bertam, 13200 Kepala Batas, Penang, Malaysia
| | - Candy Chuah
- School of Medical Sciences, Universiti Sains Malaysia, Health Campus, 16150 Kubang Kerian, Kelantan, Malaysia; Faculty of Medicine and Health Sciences, Universiti Tunku Abdul Rahman, Sungai Long Campus, Jalan Sungai Long, Bandar Sungai Long, 43200 Kajang, Selangor, Malaysia
| | - Kirnpal Kaur Banga Singh
- School of Medical Sciences, Universiti Sains Malaysia, Health Campus, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Chiuan Yee Leow
- Institute for Research in Molecular Medicine, Universiti Sains Malaysia, Health Campus, 16150 Kubang Kerian, Kelantan, Malaysia.
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Chang YY, Stévenin V, Duchateau M, Giai Gianetto Q, Hourdel V, Rodrigues CD, Matondo M, Reiling N, Enninga J. Shigella hijacks the exocyst to cluster macropinosomes for efficient vacuolar escape. PLoS Pathog 2020; 16:e1008822. [PMID: 32866204 PMCID: PMC7485983 DOI: 10.1371/journal.ppat.1008822] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 09/11/2020] [Accepted: 07/20/2020] [Indexed: 12/15/2022] Open
Abstract
Shigella flexneri invades host cells by entering within a bacteria-containing vacuole (BCV). In order to establish its niche in the host cytosol, the bacterium ruptures its BCV. Contacts between S. flexneri BCV and infection-associated macropinosomes (IAMs) formed in situ have been reported to enhance BCV disintegration. The mechanism underlying S. flexneri vacuolar escape remains however obscure. To decipher the molecular mechanism priming the communication between the IAMs and S. flexneri BCV, we performed mass spectrometry-based analysis of the magnetically purified IAMs from S. flexneri-infected cells. While proteins involved in host recycling and exocytic pathways were significantly enriched at the IAMs, we demonstrate more precisely that the S. flexneri type III effector protein IpgD mediates the recruitment of the exocyst to the IAMs through the Rab8/Rab11 pathway. This recruitment results in IAM clustering around S. flexneri BCV. More importantly, we reveal that IAM clustering subsequently facilitates an IAM-mediated unwrapping of the ruptured vacuole membranes from S. flexneri, enabling the naked bacterium to be ready for intercellular spread via actin-based motility. Taken together, our work untangles the molecular cascade of S. flexneri-driven host trafficking subversion at IAMs to develop its cytosolic lifestyle, a crucial step en route for infection progression at cellular and tissue level.
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Affiliation(s)
- Yuen-Yan Chang
- Dynamics of Host-Pathogen Interactions Unit and CNRS UMR3691, Institut Pasteur, Paris, France
| | - Virginie Stévenin
- Dynamics of Host-Pathogen Interactions Unit and CNRS UMR3691, Institut Pasteur, Paris, France
| | - Magalie Duchateau
- Mass Spectrometry for Biology Unit, Proteomics Platform, Institut Pasteur, USR CNRS, Paris, France
| | - Quentin Giai Gianetto
- Mass Spectrometry for Biology Unit, Proteomics Platform, Institut Pasteur, USR CNRS, Paris, France
- Hub Bioinformatics et Biostatistics, Computational Biology Department, USR CNRS, Institut Pasteur, Paris, France
| | - Veronique Hourdel
- Mass Spectrometry for Biology Unit, Proteomics Platform, Institut Pasteur, USR CNRS, Paris, France
| | - Cristina Dias Rodrigues
- Dynamics of Host-Pathogen Interactions Unit and CNRS UMR3691, Institut Pasteur, Paris, France
| | - Mariette Matondo
- Mass Spectrometry for Biology Unit, Proteomics Platform, Institut Pasteur, USR CNRS, Paris, France
| | - Norbert Reiling
- Microbial Interface Biology, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
- German Center for Infection Research (DZIF), Partner site Hamburg-Lübeck-Borstel, Borstel, Germany
| | - Jost Enninga
- Dynamics of Host-Pathogen Interactions Unit and CNRS UMR3691, Institut Pasteur, Paris, France
- * E-mail:
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Gonzales JC, Seribelli AA, Gomes CN, Dos Prazeres Rodrigues D, Campioni F, Passaglia J, da Silva P, Falcão JP. A high number of multidrug-resistant and predominant genetically related cluster of Shigella flexneri strains isolated over 34 years in Brazil. Braz J Microbiol 2020; 51:1563-1571. [PMID: 32710175 DOI: 10.1007/s42770-020-00332-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 06/29/2020] [Indexed: 11/26/2022] Open
Abstract
Shigella flexneri has been a major public health problem in developing countries. This work analyzed the frequency of 16 virulence genes, the genotypic diversity, and the antimicrobial resistance profiles of 130 S. flexneri strains isolated in Brazil. The ipaH gene was found in all the 130 strains. The frequencies of the other genes were variable ial (88.5%), sigA (82.3%), iuc (74.6%), virA (73%), pic (72.3%), virF (57.7%), sat (48.5%), ipaBCD (37%), sen (36%), set1A (35.4%), sepA (30%), set1B (30%), virB (14%), icsA (10%), and ipgD (5.4%). A total of 57 (43.8%) strains were multidrug-resistant. ERIC-PCR grouped 96 of the strains into a single cluster with ≥ 70.4% of similarity, 75 of these strains presented a similarity ≥ 80.9%. PFGE grouped 120 of the strains into a single cluster with 57.4% of similarity and 82 of these strains presented a similarity ≥ 70.6%. In conclusion, the high frequency of some virulence genes reinforces the pathogenic potential of the strains studied. The high rates of MDR strains are alarming once it may lead to failure when antimicrobial treatment is necessary. Genotype techniques reveled a major cluster with high genetic similarity including S. flexneri strains from the different Brazilian states and distinct years of isolation, showing that they probably emerged from a common ancestor.
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Affiliation(s)
- Júlia Cunha Gonzales
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo-USP, Av. do Café, s/no-Campus Universitário USP, Ribeirão Preto, SP, 14040-903, Brazil
| | - Amanda Aparecida Seribelli
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo-USP, Av. do Café, s/no-Campus Universitário USP, Ribeirão Preto, SP, 14040-903, Brazil
| | - Carolina Nogueira Gomes
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo-USP, Av. do Café, s/no-Campus Universitário USP, Ribeirão Preto, SP, 14040-903, Brazil
| | | | - Fábio Campioni
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo-USP, Av. do Café, s/no-Campus Universitário USP, Ribeirão Preto, SP, 14040-903, Brazil
| | - Jaqueline Passaglia
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo-USP, Av. do Café, s/no-Campus Universitário USP, Ribeirão Preto, SP, 14040-903, Brazil
| | - Paulo da Silva
- Instituto Adolfo Lutz de Ribeirão Preto, São Paulo, Brazil
| | - Juliana Pfrimer Falcão
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo-USP, Av. do Café, s/no-Campus Universitário USP, Ribeirão Preto, SP, 14040-903, Brazil.
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Sen T, Verma NK. Functional Annotation and Curation of Hypothetical Proteins Present in A Newly Emerged Serotype 1c of Shigella flexneri: Emphasis on Selecting Targets for Virulence and Vaccine Design Studies. Genes (Basel) 2020; 11:genes11030340. [PMID: 32210046 PMCID: PMC7141135 DOI: 10.3390/genes11030340] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/18/2020] [Accepted: 03/19/2020] [Indexed: 01/28/2023] Open
Abstract
Shigella flexneri is the principal cause of bacillary dysentery, contributing significantly to the global burden of diarrheal disease. The appearance and increase in the multi-drug resistance among Shigella strains, necessitates further genetic studies and development of improved/new drugs against the pathogen. The presence of an abundance of hypothetical proteins in the genome and how little is known about them, make them interesting genetic targets. The present study aims to carry out characterization of the hypothetical proteins present in the genome of a newly emerged serotype of S. flexneri (strain Y394), toward their novel regulatory functions using various bioinformatics databases/tools. Analysis of the genome sequence rendered 4170 proteins, out of which 721 proteins were annotated as hypothetical proteins (HPs) with no known function. The amino acid sequences of these HPs were evaluated using a combination of latest bioinformatics tools based on homology search against functionally identified proteins. Functional domains were considered as the basis to infer the biological functions of HPs in this case and the annotation helped in assigning various classes to the proteins such as signal transducers, lipoproteins, enzymes, membrane proteins, transporters, virulence, and binding proteins. This study contributes to a better understanding of growth, survival, and disease mechanism at molecular level and provides potential new targets for designing drugs against Shigella infection.
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9
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Russo BC, Duncan JK, Wiscovitch AL, Hachey AC, Goldberg MB. Activation of Shigella flexneri type 3 secretion requires a host-induced conformational change to the translocon pore. PLoS Pathog 2019; 15:e1007928. [PMID: 31725799 PMCID: PMC6879154 DOI: 10.1371/journal.ppat.1007928] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 11/26/2019] [Accepted: 09/30/2019] [Indexed: 12/17/2022] Open
Abstract
Type 3 secretion systems (T3SSs) are conserved bacterial nanomachines that inject virulence proteins (effectors) into eukaryotic cells during infection. Due to their ability to inject heterologous proteins into human cells, these systems are being developed as therapeutic delivery devices. The T3SS assembles a translocon pore in the plasma membrane and then docks onto the pore. Docking activates effector secretion through the pore and into the host cytosol. Here, using Shigella flexneri, a model pathogen for the study of type 3 secretion, we determined the molecular mechanisms by which host intermediate filaments trigger docking and enable effector secretion. We show that the interaction of intermediate filaments with the translocon pore protein IpaC changed the pore's conformation in a manner that was required for docking. Intermediate filaments repositioned residues of the Shigella pore protein IpaC that are located on the surface of the pore and in the pore channel. Restricting these conformational changes blocked docking in an intermediate filament-dependent manner. These data demonstrate that a host-induced conformational change to the pore enables T3SS docking and effector secretion, providing new mechanistic insight into the regulation of type 3 secretion.
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Affiliation(s)
- Brian C. Russo
- Center for Bacterial Pathogenesis, Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jeffrey K. Duncan
- Center for Bacterial Pathogenesis, Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Alexandra L. Wiscovitch
- Center for Bacterial Pathogenesis, Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Research Scholar Initiative, The Graduate School of Arts and Sciences, Harvard University, Cambridge, Massachusetts, United States of America
| | - Austin C. Hachey
- Center for Bacterial Pathogenesis, Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Marcia B. Goldberg
- Center for Bacterial Pathogenesis, Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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10
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Pizarro-Cerda J, Tran Van Nhieu G. Philippe Sansonetti and Cellular Microbiology. Cell Microbiol 2019; 21:e13134. [PMID: 31664785 DOI: 10.1111/cmi.13134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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11
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Karney MM, McKenna JA, Weatherspoon-Griffin N, Karabachev AD, Millar ME, Potocek EA, Wing HJ. Investigating the DNA-Binding Site for VirB, a Key Transcriptional Regulator of Shigella Virulence Genes, Using an In Vivo Binding Tool. Genes (Basel) 2019; 10:genes10020149. [PMID: 30781432 PMCID: PMC6410309 DOI: 10.3390/genes10020149] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 02/04/2019] [Accepted: 02/12/2019] [Indexed: 11/24/2022] Open
Abstract
The transcriptional anti-silencing and DNA-binding protein, VirB, is essential for the virulence of Shigella species and, yet, sequences required for VirB-DNA binding are poorly understood. While a 7-8 bp VirB-binding site has been proposed, it was derived from studies at a single VirB-dependent promoter, icsB. Our previous in vivo studies at a different VirB-dependent promoter, icsP, found that the proposed VirB-binding site was insufficient for regulation. Instead, the required site was found to be organized as a near-perfect inverted repeat separated by a single nucleotide spacer. Thus, the proposed 7-8 bp VirB-binding site needed to be re-evaluated. Here, we engineer and validate a molecular tool to capture protein-DNA binding interactions in vivo. Our data show that a sequence organized as a near-perfect inverted repeat is required for VirB-DNA binding interactions in vivo at both the icsB and icsP promoters. Furthermore, the previously proposed VirB-binding site and multiple sites found as a result of its description (i.e., sites located at the virB, virF, spa15, and virA promoters) are not sufficient for VirB to bind in vivo using this tool. The implications of these findings are discussed.
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Affiliation(s)
- Monika Ma Karney
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154-4004, USA.
| | - Joy A McKenna
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154-4004, USA.
| | | | | | - Makensie E Millar
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154-4004, USA.
| | - Eliese A Potocek
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154-4004, USA.
| | - Helen J Wing
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154-4004, USA.
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12
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Krokowski S, Lobato-Márquez D, Chastanet A, Pereira PM, Angelis D, Galea D, Larrouy-Maumus G, Henriques R, Spiliotis ET, Carballido-López R, Mostowy S. Septins Recognize and Entrap Dividing Bacterial Cells for Delivery to Lysosomes. Cell Host Microbe 2018; 24:866-874.e4. [PMID: 30543779 PMCID: PMC6299245 DOI: 10.1016/j.chom.2018.11.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 08/14/2018] [Accepted: 11/05/2018] [Indexed: 12/31/2022]
Abstract
The cytoskeleton occupies a central role in cellular immunity by promoting bacterial sensing and antibacterial functions. Septins are cytoskeletal proteins implicated in various cellular processes, including cell division. Septins also assemble into cage-like structures that entrap cytosolic Shigella, yet how septins recognize bacteria is poorly understood. Here, we discover that septins are recruited to regions of micron-scale membrane curvature upon invasion and division by a variety of bacterial species. Cardiolipin, a curvature-specific phospholipid, promotes septin recruitment to highly curved membranes of Shigella, and bacterial mutants lacking cardiolipin exhibit less septin cage entrapment. Chemically inhibiting cell separation to prolong membrane curvature or reducing Shigella cell growth respectively increases and decreases septin cage formation. Once formed, septin cages inhibit Shigella cell division upon recruitment of autophagic and lysosomal machinery. Thus, recognition of dividing bacterial cells by the septin cytoskeleton is a powerful mechanism to restrict the proliferation of intracellular bacterial pathogens.
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Affiliation(s)
- Sina Krokowski
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK; Department of Immunology & Infection, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
| | - Damián Lobato-Márquez
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK; Department of Immunology & Infection, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
| | - Arnaud Chastanet
- MICALIS, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas 78350, France
| | - Pedro Matos Pereira
- Quantitative Imaging and NanoBiophysics Group, MRC Laboratory for Molecular Cell Biology and Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Dimitrios Angelis
- Department of Biology, Drexel University, Philadelphia, PA 19104, USA
| | - Dieter Galea
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Gerald Larrouy-Maumus
- Faculty of Natural Sciences, Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Ricardo Henriques
- Quantitative Imaging and NanoBiophysics Group, MRC Laboratory for Molecular Cell Biology and Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Elias T Spiliotis
- Department of Biology, Drexel University, Philadelphia, PA 19104, USA
| | - Rut Carballido-López
- MICALIS, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas 78350, France
| | - Serge Mostowy
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK; Department of Immunology & Infection, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK.
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Liu W, Zhou Y, Peng T, Zhou P, Ding X, Li Z, Zhong H, Xu Y, Chen S, Hang HC, Shao F. N ε-fatty acylation of multiple membrane-associated proteins by Shigella IcsB effector to modulate host function. Nat Microbiol 2018; 3:996-1009. [PMID: 30061757 PMCID: PMC6466622 DOI: 10.1038/s41564-018-0215-6] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 06/27/2018] [Indexed: 11/09/2022]
Abstract
Shigella flexneri, an intracellular Gram-negative bacterium causative for shigellosis, employs a type III secretion system to deliver virulence effectors into host cells. One such effector, IcsB, is critical for S. flexneri intracellular survival and pathogenesis, but its mechanism of action is unknown. Here, we discover that IcsB is an 18-carbon fatty acyltransferase catalysing lysine Nε-fatty acylation. IcsB disrupted the actin cytoskeleton in eukaryotes, resulting from Nε-fatty acylation of RhoGTPases on lysine residues in their polybasic region. Chemical proteomic profiling identified about 60 additional targets modified by IcsB during infection, which were validated by biochemical assays. Most IcsB targets are membrane-associated proteins bearing a lysine-rich polybasic region, including members of the Ras, Rho and Rab families of small GTPases. IcsB also modifies SNARE proteins and other non-GTPase substrates, suggesting an extensive interplay between S. flexneri and host membrane trafficking. IcsB is localized on the Shigella-containing vacuole to fatty-acylate its targets. Knockout of CHMP5-one of the IcsB targets and a component of the ESCRT-III complex-specifically affected S. flexneri escape from host autophagy. The unique Nε-fatty acyltransferase activity of IcsB and its altering of the fatty acylation landscape of host membrane proteomes represent an unprecedented mechanism in bacterial pathogenesis.
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Affiliation(s)
- Wang Liu
- College of Life Science, Peking University, Beijing, China
- Peking University-Tsinghua University-National Institute of Biological Sciences Joint Graduate Program, National Institute of Biological Sciences, Beijing, China
- National Institute of Biological Sciences, Beijing, China
| | - Yan Zhou
- National Institute of Biological Sciences, Beijing, China
- College of Life Sciences, Beijing Normal University, Beijing, China
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang, China
| | - Tao Peng
- School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY, USA
| | - Ping Zhou
- National Institute of Biological Sciences, Beijing, China
| | - Xiaojun Ding
- National Institute of Biological Sciences, Beijing, China
| | - Zilin Li
- National Institute of Biological Sciences, Beijing, China
| | - Haoyu Zhong
- National Institute of Biological Sciences, Beijing, China
| | - Yue Xu
- National Institute of Biological Sciences, Beijing, China
| | - She Chen
- National Institute of Biological Sciences, Beijing, China
| | - Howard C Hang
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY, USA.
| | - Feng Shao
- National Institute of Biological Sciences, Beijing, China.
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China.
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14
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Weatherspoon-Griffin N, Picker MA, Pew KL, Park HS, Ginete DR, Karney MMA, Usufzy P, Castellanos MI, Duhart JC, Harrison DJ, Socea JN, Karabachev AD, Hensley CT, Howerton AJ, Ojeda-Daulo R, Immak JA, Wing HJ. Insights into transcriptional silencing and anti-silencing in Shigella flexneri: a detailed molecular analysis of the icsP virulence locus. Mol Microbiol 2018; 108:505-518. [PMID: 29453862 PMCID: PMC6311345 DOI: 10.1111/mmi.13932] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/14/2018] [Indexed: 11/28/2022]
Abstract
Transcriptional silencing and anti-silencing mechanisms modulate bacterial physiology and virulence in many human pathogens. In Shigella species, many virulence plasmid genes are silenced by the histone-like nucleoid structuring protein H-NS and anti-silenced by the virulence gene regulator VirB. Despite the key role that these regulatory proteins play in Shigella virulence, their mechanisms of transcriptional control remain poorly understood. Here, we characterize the regulatory elements and their relative spacing requirements needed for the transcriptional silencing and anti-silencing of icsP, a locus that requires remotely located regulatory elements for both types of transcriptional control. Our findings highlight the flexibility of the regulatory elements' positions with respect to each other, and yet, a molecular roadblock docked between the VirB binding site and the upstream H-NS binding region abolishes transcriptional anti-silencing by VirB, providing insight into transcriptional anti-silencing. Our study also raises the need to re-evaluate the currently proposed VirB binding site. Models of transcriptional silencing and anti-silencing at this genetic locus are presented, and the implications for understanding these regulatory mechanisms in bacteria are discussed.
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Affiliation(s)
| | | | - Krystle L. Pew
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV 89154-4004, USA
| | - Hiromichi S. Park
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV 89154-4004, USA
| | - Daren R. Ginete
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV 89154-4004, USA
| | - Monika MA. Karney
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV 89154-4004, USA
| | - Pashtana Usufzy
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV 89154-4004, USA
| | - Maria I. Castellanos
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV 89154-4004, USA
| | - Juan Carlos Duhart
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV 89154-4004, USA
| | - Dustin J. Harrison
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV 89154-4004, USA
| | - Jillian N. Socea
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV 89154-4004, USA
| | | | | | | | - Rosa Ojeda-Daulo
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV 89154-4004, USA
| | - Joy A. Immak
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV 89154-4004, USA
| | - Helen J. Wing
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV 89154-4004, USA
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15
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Bernard AR, Jessop TC, Kumar P, Dickenson NE. Deoxycholate-Enhanced Shigella Virulence Is Regulated by a Rare π-Helix in the Type Three Secretion System Tip Protein IpaD. Biochemistry 2017; 56:6503-6514. [PMID: 29134812 PMCID: PMC5761661 DOI: 10.1021/acs.biochem.7b00836] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Type three secretion systems (T3SS) are specialized nanomachines that support infection by injecting bacterial proteins directly into host cells. The Shigella T3SS has uniquely evolved to sense environmental levels of the bile salt deoxycholate (DOC) and upregulate virulence in response to DOC. In this study, we describe a rare i + 5 hydrogen bonding secondary structure element (π-helix) within the type three secretion system tip protein IpaD that plays a critical role in DOC-enhanced virulence. Specifically, engineered mutations within the π-helix altered the pathogen's response to DOC, with one mutant construct in particular exhibiting an unprecedented reduction in virulence following DOC exposure. Fluorescence polarization binding assays showed that these altered DOC responses are not the result of differences in affinity between IpaD and DOC, but rather differences in the DOC-dependent T3SS tip maturation resulting from binding of IpaD to translocator/effector protein IpaB. Together, these findings begin to uncover the complex mechanism of DOC-enhanced Shigella virulence while identifying an uncommon structural element that may provide a much needed target for non-antibiotic treatment of Shigella infection.
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Affiliation(s)
- Abram R. Bernard
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322, USA
| | - T. Carson Jessop
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322, USA
| | - Prashant Kumar
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS 66047, USA
| | - Nicholas E. Dickenson
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322, USA
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Pinaud L, Ferrari ML, Friedman R, Jehmlich N, von Bergen M, Phalipon A, Sansonetti PJ, Campbell-Valois FX. Identification of novel substrates of Shigella T3SA through analysis of its virulence plasmid-encoded secretome. PLoS One 2017; 12:e0186920. [PMID: 29073283 PMCID: PMC5658099 DOI: 10.1371/journal.pone.0186920] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 10/10/2017] [Indexed: 11/19/2022] Open
Abstract
Many human Gram-negative bacterial pathogens express a Type Three Secretion Apparatus (T3SA), including among the most notorious Shigella spp., Salmonella enterica, Yersinia enterocolitica and enteropathogenic Escherichia coli (EPEC). These bacteria express on their surface multiple copies of the T3SA that mediate the delivery into host cells of specific protein substrates critical to pathogenesis. Shigella spp. are Gram-negative bacterial pathogens responsible for human bacillary dysentery. The effector function of several Shigella T3SA substrates has largely been studied but their potential cellular targets are far from having been comprehensively delineated. In addition, it is likely that some T3SA substrates have escaped scrutiny as yet. Indeed, sequencing of the virulence plasmid of Shigella flexneri has revealed numerous open reading frames with unknown functions that could encode additional T3SA substrates. Taking advantage of label-free mass spectrometry detection of proteins secreted by a constitutively secreting strain of S. flexneri, we identified five novel substrates of the T3SA. We further confirmed their secretion through the T3SA and translocation into host cells using β-lactamase assays. The coding sequences of two of these novel T3SA substrates (Orf13 and Orf131a) have a guanine-cytosine content comparable to those of T3SA components and effectors. The three other T3SA substrates identified (Orf48, Orf86 and Orf176) have significant homology with antitoxin moieties of type II Toxin-Antitoxin systems usually implicated in the maintenance of low copy plasmids. While Orf13 and Orf131a might constitute new virulence effectors contributing to S. flexneri pathogenicity, potential roles for the translocation into host cells of antitoxins or antitoxin-like proteins during Shigella infection are discussed.
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Affiliation(s)
- Laurie Pinaud
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, Paris, France
- U1202, INSERM, Paris, France
| | - Mariana L. Ferrari
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, Paris, France
- U1202, INSERM, Paris, France
| | - Robin Friedman
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, Paris, France
- U1202, INSERM, Paris, France
- Laboratoire de Biologie Systémique & Centre de Bioinformatique, Biostatistique et Biologie Intégrative, Institut Pasteur, Paris, France
| | - Nico Jehmlich
- Department of Molecular Systems Biology, Helmholtz-Centre for Environmental Research-UFZ, Leipzig, Germany
| | - Martin von Bergen
- Department of Molecular Systems Biology, Helmholtz-Centre for Environmental Research-UFZ, Leipzig, Germany
- Institute of Biochemistry, University of Leipzig, Faculty of Biosciences, Pharmacy and Psychology, Leipzig, Germany
| | - Armelle Phalipon
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, Paris, France
- U1202, INSERM, Paris, France
| | - Philippe J. Sansonetti
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, Paris, France
- U1202, INSERM, Paris, France
- Chaire de Microbiologie et Maladies Infectieuses, Collège de France, Paris, France
| | - François-Xavier Campbell-Valois
- Department of Chemistry and Biomolecular Sciences, Centre for Chemical and Synthetic Biology, Faculty of Science, University of Ottawa, Ottawa, Ontario, Canada
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
- * E-mail:
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17
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Weiner A, Mellouk N, Lopez-Montero N, Chang YY, Souque C, Schmitt C, Enninga J. Macropinosomes are Key Players in Early Shigella Invasion and Vacuolar Escape in Epithelial Cells. PLoS Pathog 2016; 12:e1005602. [PMID: 27182929 PMCID: PMC4868309 DOI: 10.1371/journal.ppat.1005602] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 04/05/2016] [Indexed: 01/30/2023] Open
Abstract
Intracellular pathogens include all viruses, many bacteria and parasites capable of invading and surviving within host cells. Key to survival is the subversion of host cell pathways by the pathogen for the purpose of propagation and evading the immune system. The intracellular bacterium Shigella flexneri, the causative agent of bacillary dysentery, invades host cells in a vacuole that is subsequently ruptured to allow growth of the pathogen within the host cytoplasm. S. flexneri invasion has been classically described as a macropinocytosis-like process, however the underlying details and the role of macropinosomes in the intracellular bacterial lifestyle have remained elusive. We applied dynamic imaging and advanced large volume correlative light electron microscopy (CLEM) to study the highly transient events of S. flexneri's early invasion into host epithelial cells and elucidate some of its fundamental features. First, we demonstrate a clear distinction between two compartments formed during the first step of invasion: the bacterial containing vacuole and surrounding macropinosomes, often considered identical. Next, we report a functional link between macropinosomes and the process of vacuolar rupture, demonstrating that rupture timing is dependent on the availability of macropinosomes as well as the activity of the small GTPase Rab11 recruited directly to macropinosomes. We go on to reveal that the bacterial containing vacuole and macropinosomes come into direct contact at the onset of vacuolar rupture. Finally, we demonstrate that S. flexneri does not subvert pre-existing host endocytic vesicles during the invasion steps leading to vacuolar rupture, and propose that macropinosomes are the major compartment involved in these events. These results provide the basis for a new model of the early steps of S. flexneri epithelial cell invasion, establishing a different view of the enigmatic process of cytoplasmic access by invasive bacterial pathogens.
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Affiliation(s)
- Allon Weiner
- Institut Pasteur, Dynamics of Host-Pathogen interactions Unit, Paris, France
- * E-mail: (AW); (JE)
| | - Nora Mellouk
- Institut Pasteur, Dynamics of Host-Pathogen interactions Unit, Paris, France
| | | | - Yuen-Yan Chang
- Institut Pasteur, Dynamics of Host-Pathogen interactions Unit, Paris, France
| | - Célia Souque
- Institut Pasteur, Dynamics of Host-Pathogen interactions Unit, Paris, France
| | | | - Jost Enninga
- Institut Pasteur, Dynamics of Host-Pathogen interactions Unit, Paris, France
- * E-mail: (AW); (JE)
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18
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Zhang H, Si Y, Wang X, Gong P. Patterns of Bacillary Dysentery in China, 2005-2010. Int J Environ Res Public Health 2016; 13:164. [PMID: 26828503 PMCID: PMC4772184 DOI: 10.3390/ijerph13020164] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 01/19/2016] [Accepted: 01/21/2016] [Indexed: 02/06/2023]
Abstract
Although the incidence of bacillary dysentery in China has been declining progressively, a considerable disease burden still exists. Few studies have analyzed bacillary dysentery across China and knowledge gaps still exist in the aspects of geographic distribution and ecological drivers, seasonality and its association with meteorological factors, urban-rural disparity, prevalence and distribution of Shigella species. Here, we performed nationwide analyses to fill the above gaps. Geographically, we found that incidence increased along an east-west gradient which was inversely related to the economic conditions of China. Two large endemically high-risk regions in western China and their ecological drivers were identified for the first time. We characterized seasonality of bacillary dysentery incidence and assessed its association with meteorological factors, and saw that it exhibits north-south differences in peak duration, relative amplitude and key meteorological factors. Urban and rural incidences among China’s cities were compared, and disparity associated with urbanization level was invariant in most cities. Balanced decrease of urban and rural incidence was observed for all provinces except Hunan. S. flexneri and S. sonnei were identified as major causative species. Increasing prevalence of S. sonnei and geographic distribution of Shigella species were associated with economic status. Findings and inferences from this study draw broader pictures of bacillary dysentery in mainland China and could provide useful information for better interventions and public health planning.
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Affiliation(s)
- Han Zhang
- Ministry of Education Key Laboratory for Earth System Modeling, Center for Earth System Science, Institute for Global Change Studies, Tsinghua University, Beijing 100084, China.
| | - Yali Si
- Ministry of Education Key Laboratory for Earth System Modeling, Center for Earth System Science, Institute for Global Change Studies, Tsinghua University, Beijing 100084, China.
- Joint Center for Global Change Studies, Beijing 100875, China.
| | - Xiaofeng Wang
- Center for Disease Surveillance and Information Services, Chinese Center for Disease Control and Prevention, Beijing 102206, China.
| | - Peng Gong
- Ministry of Education Key Laboratory for Earth System Modeling, Center for Earth System Science, Institute for Global Change Studies, Tsinghua University, Beijing 100084, China.
- Joint Center for Global Change Studies, Beijing 100875, China.
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Lu R, Herrera BB, Eshleman HD, Fu Y, Bloom A, Li Z, Sacks DB, Goldberg MB. Shigella Effector OspB Activates mTORC1 in a Manner That Depends on IQGAP1 and Promotes Cell Proliferation. PLoS Pathog 2015; 11:e1005200. [PMID: 26473364 PMCID: PMC4608727 DOI: 10.1371/journal.ppat.1005200] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 09/10/2015] [Indexed: 12/12/2022] Open
Abstract
The intracellular bacterial pathogen Shigella infects and spreads through the human intestinal epithelium. Effector proteins delivered by Shigella into cells promote infection by modulating diverse host functions. We demonstrate that the effector protein OspB interacts directly with the scaffolding protein IQGAP1, and that the absence of either OspB or IQGAP1 during infection leads to larger areas of S. flexneri spread through cell monolayers. We show that the effect on the area of bacterial spread is due to OspB triggering increased cell proliferation at the periphery of infected foci, thereby replacing some of the cells that die within infected foci and restricting the area of bacterial spread. We demonstrate that OspB enhancement of cell proliferation results from activation of mTORC1, a master regulator of cell growth, and is blocked by the mTORC1-specific inhibitor rapamycin. OspB activation of mTORC1, and its effects on cell proliferation and bacterial spread, depends on IQGAP1. Our results identify OspB as a regulator of mTORC1 and mTORC1-dependent cell proliferation early during S. flexneri infection and establish a role for IQGAP1 in mTORC1 signaling. They also raise the possibility that IQGAP1 serves as a scaffold for the assembly of an OspB-mTORC1 signaling complex. During infection, Shigella spp. deliver into the cytoplasm of cells effector proteins that manipulate host cell processes in ways that promote infection and bacterial spread. We have discovered that the Shigella effector protein OspB interacts with the cellular scaffolding protein IQGAP1. OspB induces increased cell proliferation by activating mTORC1 kinase, a master regulator of cellular growth, in a manner that depends on IQGAP1. As IQGAP1 has been shown to interact with mTOR and with the mTORC1 activators ERK1/2, we propose that IQGAP1 serves as a scaffold for OspB activation of mTORC1. The presence of OspB and IQGAP1 lead to restricting the area of spread of S. flexneri in cell monolayers; our data support a model in which the effect of OspB and IQGAP1 on the area of S. flexneri spread is due to effects on cell proliferation locally within infected foci. As infection of cells and tissue by Shigella spp. leads to cell death, increased local cellular proliferation may serve to provide additional protective intracellular niches for the organism within infected tissue.
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Affiliation(s)
- Richard Lu
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Cambridge, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Bobby Brooke Herrera
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Cambridge, Massachusetts, United States of America
| | - Heather D. Eshleman
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Cambridge, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Yang Fu
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Cambridge, Massachusetts, United States of America
| | - Alexander Bloom
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Cambridge, Massachusetts, United States of America
| | - Zhigang Li
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
| | - David B. Sacks
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Marcia B. Goldberg
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Cambridge, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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Leuzzi A, Di Martino ML, Campilongo R, Falconi M, Barbagallo M, Marcocci L, Pietrangeli P, Casalino M, Grossi M, Micheli G, Colonna B, Prosseda G. Multifactor Regulation of the MdtJI Polyamine Transporter in Shigella. PLoS One 2015; 10:e0136744. [PMID: 26313003 PMCID: PMC4636849 DOI: 10.1371/journal.pone.0136744] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 08/06/2015] [Indexed: 01/19/2023] Open
Abstract
The polyamine profile of Shigella, the etiological agent of bacillary dysentery in humans, differs markedly from that of E. coli, its innocuous commensal ancestor. Pathoadaptive mutations such as the loss of cadaverine and the increase of spermidine favour the full expression of the virulent phenotype of Shigella. Spermidine levels affect the expression of the MdtJI complex, a recently identified efflux pump belonging to the small multi-drug resistance family of transporters. In the present study, we have addressed the regulation of the mdtJI operon in Shigella by asking which factors influence its expression as compared to E. coli. In particular, after identifying the mdtJI promoter by primer extension analysis, in vivo transcription assays and gel-retardation experiments were carried out to get insight on the silencing of mdtJI in E. coli. The results indicate that H-NS, a major nucleoid protein, plays a key role in repressing the mdtJI operon by direct binding to the regulatory region. In the Shigella background mdtJI expression is increased by the high levels of spermidine typically found in this microorganism and by VirF, the plasmid-encoded regulator of the Shigella virulence regulatory cascade. We also show that the expression of mdtJI is stimulated by bile components. Functional analyses reveal that MdtJI is able to promote the excretion of putrescine, the spermidine precursor. This leads us to consider the MdtJI complex as a possible safety valve allowing Shigella to maintain spermidine to a level optimally suited to survival within infected macrophages and, at the same time, prevent toxicity due to spermidine over-accumulation.
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Affiliation(s)
- Adriano Leuzzi
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Via dei Sardi 70, 00185, Roma, Italy
| | - Maria Letizia Di Martino
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Via dei Sardi 70, 00185, Roma, Italy
| | - Rosaria Campilongo
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Via dei Sardi 70, 00185, Roma, Italy
| | - Maurizio Falconi
- Laboratorio di Genetica Molecolare e dei Microrganismi, Scuola di Bioscienze e Medicina Veterinaria, Università di Camerino, Via Gentile III da Varano, Camerino, Italy
| | - Marialuisa Barbagallo
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Via dei Sardi 70, 00185, Roma, Italy
| | - Lucia Marcocci
- Dipartimento di Biochimica, Sapienza Università di Roma, P.le A. Moro 5, 00185, Roma, Italy
| | - Paola Pietrangeli
- Dipartimento di Biochimica, Sapienza Università di Roma, P.le A. Moro 5, 00185, Roma, Italy
| | - Mariassunta Casalino
- Dipartimento di Scienze, Università Roma Tre, Viale G. Marconi 446, 00146, Roma, Italy
| | - Milena Grossi
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Via dei Sardi 70, 00185, Roma, Italy
| | - Gioacchino Micheli
- Istituto di Biologia e Patologia molecolari CNR, P.le A. Moro 5, 00185, Roma, Italy
| | - Bianca Colonna
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Via dei Sardi 70, 00185, Roma, Italy
| | - Gianni Prosseda
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Via dei Sardi 70, 00185, Roma, Italy
- * E-mail:
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Gray MD, Lampel KA, Strockbine NA, Fernandez RE, Melton-Celsa AR, Maurelli AT. Clinical isolates of Shiga toxin 1a-producing Shigella flexneri with an epidemiological link to recent travel to Hispañiola. Emerg Infect Dis 2015; 20:1669-77. [PMID: 25271406 PMCID: PMC4193171 DOI: 10.3201/eid2010.140292] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Shiga toxins (Stx) are cytotoxins involved in severe human intestinal disease. These toxins are commonly found in Shigella dysenteriae serotype 1 and Shiga-toxin-producing Escherichia coli; however, the toxin genes have been found in other Shigella species. We identified 26 Shigella flexneri serotype 2 strains isolated by public health laboratories in the United States during 2001-2013, which encode the Shiga toxin 1a gene (stx1a). These strains produced and released Stx1a as measured by cytotoxicity and neutralization assays using anti-Stx/Stx1a antiserum. The release of Stx1a into culture supernatants increased ≈100-fold after treatment with mitomycin C, suggesting that stx1a is carried by a bacteriophage. Infectious phage were found in culture supernatants and increased ≈1,000-fold with mitomycin C. Whole-genome sequencing of several isolates and PCR analyses of all strains confirmed that stx1a was carried by a lambdoid bacteriophage. Furthermore, all patients who reported foreign travel had recently been to Hispañiola, suggesting that emergence of these novel strains is associated with that region.
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22
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George DT, Behm CA, Hall DH, Mathesius U, Rug M, Nguyen KCQ, Verma NK. Shigella flexneri infection in Caenorhabditis elegans: cytopathological examination and identification of host responses. PLoS One 2014; 9:e106085. [PMID: 25187942 PMCID: PMC4154869 DOI: 10.1371/journal.pone.0106085] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Accepted: 07/30/2014] [Indexed: 01/08/2023] Open
Abstract
The Gram-negative bacterium Shigella flexneri is the causative agent of shigellosis, a diarrhoeal disease also known as bacillary dysentery. S. flexneri infects the colonic and rectal epithelia of its primate host and induces a cascade of inflammatory responses that culminates in the destruction of the host intestinal lining. Molecular characterization of host-pathogen interactions in this infection has been challenging due to the host specificity of S. flexneri strains, as it strictly infects humans and non-human primates. Recent studies have shown that S. flexneri infects the soil dwelling nematode Caenorhabditis elegans, however, the interactions between S. flexneri and C. elegans at the cellular level and the cause of nematode death are unknown. Here we attempt to gain insight into the complex host-pathogen interactions between S. flexneri and C. elegans. Using transmission electron microscopy, we show that live S. flexneri cells accumulate in the nematode intestinal lumen, produce outer membrane vesicles and invade nematode intestinal cells. Using two-dimensional differential in-gel electrophoresis we identified host proteins that are differentially expressed in response to S. flexneri infection. Four of the identified genes, aco-1, cct-2, daf-19 and hsp-60, were knocked down using RNAi and ACO-1, CCT-2 and DAF-19, which were identified as up-regulated in response to S. flexneri infection, were found to be involved in the infection process. aco-1 RNAi worms were more resistant to S. flexneri infection, suggesting S. flexneri-mediated disruption of host iron homeostasis. cct-2 and daf-19 RNAi worms were more susceptible to infection, suggesting that these genes are induced as a protective mechanism by C. elegans. These observations further our understanding of the processes involved in S. flexneri infection of C. elegans, which is immensely beneficial to the routine use of this new in vivo model to study S. flexneri pathogenesis.
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Affiliation(s)
- Divya T. George
- Division of Biomedical Science and Biochemistry, Research School of Biology, The Australian National University, Canberra, Australia
| | - Carolyn A. Behm
- Division of Biomedical Science and Biochemistry, Research School of Biology, The Australian National University, Canberra, Australia
| | - David H. Hall
- Center for C. elegans Anatomy, Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Ulrike Mathesius
- Division of Plant Science, Research School of Biology, The Australian National University, Canberra, Australia
| | - Melanie Rug
- Centre for Advanced Microscopy, The Australian National University, Canberra, Australia
| | - Ken C. Q. Nguyen
- Center for C. elegans Anatomy, Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Naresh K. Verma
- Division of Biomedical Science and Biochemistry, Research School of Biology, The Australian National University, Canberra, Australia
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23
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Longet S, Vonarburg C, Lötscher M, Miescher S, Zuercher A, Corthésy B. Reconstituted human polyclonal plasma-derived secretory-like IgM and IgA maintain the barrier function of epithelial cells infected with an enteropathogen. J Biol Chem 2014; 289:21617-26. [PMID: 24951593 PMCID: PMC4118121 DOI: 10.1074/jbc.m114.549139] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 06/13/2014] [Indexed: 01/05/2023] Open
Abstract
Intravenous administration of polyclonal and monoclonal antibodies has proven to be a clinically valid approach in the treatment, or at least relief, of many acute and chronic pathologies, such as infection, immunodeficiency, and a broad range of autoimmune conditions. Plasma-derived IgG or recombinant IgG are most frequently used for intravenous or subcutaneous administration, whereas a few IgM-based products are available as well. We have established recently that secretory-like IgA and IgM can be produced upon association of plasma-derived polymeric IgA and IgM with a recombinant secretory component. As a next step toward potential future mucosal administration, we sought to unravel the mechanisms by which these secretory Igs protect epithelial cells located at the interface between the environment and the inside of the body. By using polarized epithelial Caco-2 cell monolayers and Shigella flexneri as a model enteropathogen, we found that polyspecific plasma-derived SIgA and SIgM fulfill many protective functions, including dose-dependent recognition of the antigen via formation of aggregated immune complexes, reduction of bacterial infectivity, maintenance of epithelial cell integrity, and inhibition of proinflammatory cytokine/chemokine production by epithelial cells. In this in vitro model devoid of other cellular or molecular interfering partners, IgM and secretory IgM showed stronger bacterial neutralization than secretory IgA. Together, these data suggest that mucosally delivered antibody preparations may be most effective when combining both secretory-like IgA and IgM, which, together, play a crucial role in preserving several levels of epithelial cell integrity.
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Affiliation(s)
- Stéphanie Longet
- From the R&D Laboratory of the Division of Immunology and Allergy, Centre Hospitalier Universitaire Vaudois, Rue du Bugnon, 1011 Lausanne, Switzerland and
| | | | - Marius Lötscher
- CSL Behring AG, Wankdorfstrasse 10, 3000 Bern 22, Switzerland
| | - Sylvia Miescher
- CSL Behring AG, Wankdorfstrasse 10, 3000 Bern 22, Switzerland
| | - Adrian Zuercher
- CSL Behring AG, Wankdorfstrasse 10, 3000 Bern 22, Switzerland
| | - Blaise Corthésy
- From the R&D Laboratory of the Division of Immunology and Allergy, Centre Hospitalier Universitaire Vaudois, Rue du Bugnon, 1011 Lausanne, Switzerland and CSL Behring AG, Wankdorfstrasse 10, 3000 Bern 22, Switzerland
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24
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Grishin AM, Condos TEC, Barber KR, Campbell-Valois FX, Parsot C, Shaw GS, Cygler M. Structural basis for the inhibition of host protein ubiquitination by Shigella effector kinase OspG. Structure 2014; 22:878-88. [PMID: 24856362 DOI: 10.1016/j.str.2014.04.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Revised: 03/19/2014] [Accepted: 04/09/2014] [Indexed: 11/30/2022]
Abstract
Shigella invasion of its human host is assisted by T3SS-delivered effector proteins. The OspG effector kinase binds ubiquitin and ubiquitin-loaded E2-conjugating enzymes, including UbcH5b and UbcH7, and attenuates the host innate immune NF-kB signaling. We present the structure of OspG bound to the UbcH7∼Ub conjugate. OspG has a minimal kinase fold lacking the activation loop of regulatory kinases. UbcH7∼Ub binds OspG at sites remote from the kinase active site, yet increases its kinase activity. The ubiquitin is positioned in the "open" conformation with respect to UbcH7 using its I44 patch to interact with the C terminus of OspG. UbcH7 binds to OspG using two conserved loops essential for E3 ligase recruitment. The interaction of the UbcH7∼Ub with OspG is remarkably similar to the interaction of an E2∼Ub with a HECT E3 ligase. OspG interferes with the interaction of UbcH7 with the E3 parkin and inhibits the activity of the E3.
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Affiliation(s)
- Andrey M Grishin
- Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK S7N 5E5, Canada
| | - Tara E C Condos
- Department of Biochemistry, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Kathryn R Barber
- Department of Biochemistry, University of Western Ontario, London, ON N6A 5C1, Canada
| | | | - Claude Parsot
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, 75724 Paris, France; INSERM, U786, 75015, Paris, France
| | - Gary S Shaw
- Department of Biochemistry, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Miroslaw Cygler
- Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK S7N 5E5, Canada; Department of Biochemistry, McGill University, Montreal, QC H3G 1Y6, Canada.
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Scribano D, Petrucca A, Pompili M, Ambrosi C, Bruni E, Zagaglia C, Prosseda G, Nencioni L, Casalino M, Polticelli F, Nicoletti M. Polar localization of PhoN2, a periplasmic virulence-associated factor of Shigella flexneri, is required for proper IcsA exposition at the old bacterial pole. PLoS One 2014; 9:e90230. [PMID: 24587292 PMCID: PMC3937361 DOI: 10.1371/journal.pone.0090230] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 01/27/2014] [Indexed: 12/18/2022] Open
Abstract
Proper protein localization is critical for bacterial virulence. PhoN2 is a virulence-associated ATP-diphosphohydrolase (apyrase) involved in IcsA-mediated actin-based motility of S. flexneri. Herein, by analyzing a ΔphoN2 mutant of the S. flexneri strain M90T and by generating phoN2::HA fusions, we show that PhoN2, is a periplasmic protein that strictly localizes at the bacterial poles, with a strong preference for the old pole, the pole where IcsA is exposed, and that it is required for proper IcsA exposition. PhoN2-HA was found to be polarly localized both when phoN2::HA was ectopically expressed in a Escherichia coli K-12 strain and in a S. flexneri virulence plasmid-cured mutant, indicating a conserved mechanism of PhoN2 polar delivery across species and that neither IcsA nor the expression of other virulence-plasmid encoded genes are involved in this process. To assess whether PhoN2 and IcsA may interact, two-hybrid and cross-linking experiments were performed. While no evidence was found of a PhoN2-IcsA interaction, unexpectedly the outer membrane protein A (OmpA) was shown to bind PhoN2-HA through its periplasmic-exposed C-terminal domain. Therefore, to identify PhoN2 domains involved in its periplasmic polar delivery as well as in the interaction with OmpA, a deletion and a set of specific amino acid substitutions were generated. Analysis of these mutants indicated that neither the (183)PAPAP(187) motif of OmpA, nor the N-terminal polyproline (43)PPPP(46) motif and the Y155 residue of PhoN2 are involved in this interaction while P45, P46 and Y155 residues were found to be critical for the correct folding and stability of the protein. The relative rapid degradation of these amino acid-substituted recombinant proteins was found to be due to unknown S. flexneri-specific protease(s). A model depicting how the PhoN2-OmpA interaction may contribute to proper polar IcsA exposition in S. flexneri is presented.
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Affiliation(s)
- Daniela Scribano
- Dipartimento di Scienze Sperimentali e Cliniche, Università “G. D'Annunzio”, Chieti, Italy
| | - Andrea Petrucca
- Dipartimento di Scienze Sperimentali e Cliniche, Università “G. D'Annunzio”, Chieti, Italy
| | - Monica Pompili
- Dipartimento di Sanità Pubblica e Malattie Infettive Università “Sapienza” di Roma, Rome, Italy
| | - Cecilia Ambrosi
- Dipartimento di Sanità Pubblica e Malattie Infettive Università “Sapienza” di Roma, Rome, Italy
| | - Elena Bruni
- Dipartimento di Sanità Pubblica e Malattie Infettive Università “Sapienza” di Roma, Rome, Italy
| | - Carlo Zagaglia
- Dipartimento di Sanità Pubblica e Malattie Infettive Università “Sapienza” di Roma, Rome, Italy
| | - Gianni Prosseda
- Dipartimento di Biologia e Biotecnologie “C. Darwin”, Università Sapienza di Roma, Rome, Italy
| | - Lucia Nencioni
- Dipartimento di Sanità Pubblica e Malattie Infettive Università “Sapienza” di Roma, Rome, Italy
| | | | - Fabio Polticelli
- Dipartimento di Scienze, Università di “Roma Tre”, Rome, Italy
- Istituto Nazionale di Fisica Nucleare, Sezione di “Roma Tre”, Rome, Italy
| | - Mauro Nicoletti
- Dipartimento di Scienze Sperimentali e Cliniche, Università “G. D'Annunzio”, Chieti, Italy
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Fiorentino M, Levine MM, Sztein MB, Fasano A. Effect of wild-type Shigella species and attenuated Shigella vaccine candidates on small intestinal barrier function, antigen trafficking, and cytokine release. PLoS One 2014; 9:e85211. [PMID: 24416363 PMCID: PMC3887025 DOI: 10.1371/journal.pone.0085211] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 11/27/2013] [Indexed: 01/22/2023] Open
Abstract
Bacterial dysentery due to Shigella species is a major cause of morbidity and mortality worldwide. The pathogenesis of Shigella is based on the bacteria's ability to invade and replicate within the colonic epithelium, resulting in severe intestinal inflammatory response and epithelial destruction. Although the mechanisms of pathogenesis of Shigella in the colon have been extensively studied, little is known on the effect of wild-type Shigella on the small intestine and the role of the host response in the development of the disease. Moreover, to the best of our knowledge no studies have described the effects of apically administered Shigella flexneri 2a and S. dysenteriae 1 vaccine strains on human small intestinal enterocytes. The aim of this study was to assess the coordinated functional and immunological human epithelial responses evoked by strains of Shigella and candidate vaccines on small intestinal enterocytes. To model the interactions of Shigella with the intestinal mucosa, we apically exposed monolayers of human intestinal Caco2 cells to increasing bacterial inocula. We monitored changes in paracellular permeability, examined the organization of tight-junctions and the pro-inflammatory response of epithelial cells. Shigella infection of Caco2 monolayers caused severe mucosal damage, apparent as a drastic increase in paracellular permeability and disruption of tight junctions at the cell-cell boundary. Secretion of pro-inflammatory IL-8 was independent of epithelial barrier dysfunction. Shigella vaccine strains elicited a pro-inflammatory response without affecting the intestinal barrier integrity. Our data show that wild-type Shigella infection causes a severe alteration of the barrier function of a small intestinal cell monolayer (a proxy for mucosa) and might contribute (along with enterotoxins) to the induction of watery diarrhea. Diarrhea may be a mechanism by which the host attempts to eliminate harmful bacteria and transport them from the small to the large intestine where they invade colonocytes inducing a strong inflammatory response.
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Affiliation(s)
- Maria Fiorentino
- Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Myron M. Levine
- Center for Vaccine Development and the Departments of Pediatrics and Medicine, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Marcelo B. Sztein
- Center for Vaccine Development and the Departments of Pediatrics and Medicine, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Alessio Fasano
- Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
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Su WL, Chen C, Wang ZQ, Li J, He X, Sun ZN, Yang Y, Liu JM, Qiu SF, Wang Y, Song HB. [Virulence genes and pathogenicity of Shigella flexneri Xv isolated in Beijing]. Zhonghua Liu Xing Bing Xue Za Zhi 2013; 34:57-60. [PMID: 23648252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
OBJECTIVE To understand the biochemical characteristics, virulence genes and pathogenicity of Shigella flexneri Xv isolated in Beijing. METHODS 61 strains of S. flexneri Xv isolated from diarrhea patients in Beijing were systematically determined through biochemical reactions and serological tests. Application of PCR technique in detection of virulence genes on ipaH, sen, virF, ial and pulsed-field gel electrophoresis (PFGE) was used to identify the related characteristics and on rat lung slices to determine its pathogenicity. RESULTS All of the S. flexneri Xv could ferment glucose, mannitol, melibiose and arabinose. Using serum agglutination, we found that the antigen structure was (IV: 7, 8). IpaH, sen, virF and ial that carried rates of virulence genes appeared to be 100%, 81.97%, 75.41% and 80.30%, respectively. Among 61 strains of S. flexneri Xv, the PFGE typing of Shigella bacteria could be divided into 25 belt types while the results from rat lung slices showed inflammatory change of Xv. CONCLUSION S. flexneri Xv was found that it carried high rate of Shigella virulence genes, exhibiting genetic polymorphism and highly invasive.
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Affiliation(s)
- Wen-li Su
- Institute of Disease Control and Prevention Academy of Military Medical Sciences, Beijing, China
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Faherty C, Harper JM, Shea-Donohue T, Barry EM, Kaper JB, Fasano A, Nataro JP. Chromosomal and plasmid-encoded factors of Shigella flexneri induce secretogenic activity ex vivo. PLoS One 2012; 7:e49980. [PMID: 23166804 PMCID: PMC3500342 DOI: 10.1371/journal.pone.0049980] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2012] [Accepted: 10/15/2012] [Indexed: 12/22/2022] Open
Abstract
Shigella flexneri is a Gram-negative, facultative intracellular pathogen that causes millions of cases of watery or bloody diarrhea annually, resulting in significant global mortality. Watery diarrhea is thought to arise in the jejunum, and subsequent bloody diarrhea occurs as a result of invasion of the colonic epithelium. Previous literature has demonstrated that Shigella encodes enterotoxins, both chromosomally and on the 220 kilobase virulence plasmid. The ShigellaEnterotoxins 1 and 2 (ShET1 and ShET2) have been shown to increase water accumulation in the rabbit ileal loop model. In addition, these toxins increase the short circuit current in rabbit tissue mounted in Ussing chambers, which is a model for the ion exchange that occurs during watery diarrhea. In this study, we sought to validate the use of mouse jejunum in Ussing chamber as an alternative, more versatile model to study bacterial pathogenesis. In the process, we also identified enterotoxins in addition to ShET1 and ShET2 encoded by S. flexneri. Through analysis of proteins secreted from wildtype bacteria and various deletion mutants, we have identified four factors responsible for enterotoxin activity: ShET1 and Pic, which are encoded on the chromosome; ShET2 (encoded by sen or ospD3), which requires the type-III secretion system for secretion; and SepA, an additional factor encoded on the virulence plasmid. The use of mouse jejunum serves as a reliable and reproducible model to identify the enterotoxins elaborated by enteric bacteria. Moreover, the identification of all Shigella proteins responsible for enterotoxin activity is vital to our understanding of Shigella pathogenicity and to our success in developing safe and effective vaccine candidates.
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Affiliation(s)
- Christina Faherty
- Department of Medicine, Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Jill M. Harper
- Mucosal Biology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Terez Shea-Donohue
- Mucosal Biology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Eileen M. Barry
- Department of Medicine, Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - James B. Kaper
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Alessio Fasano
- Mucosal Biology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
| | - James P. Nataro
- Department of Medicine, Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
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Ambrosi C, Pompili M, Scribano D, Zagaglia C, Ripa S, Nicoletti M. Outer membrane protein A (OmpA): a new player in shigella flexneri protrusion formation and inter-cellular spreading. PLoS One 2012; 7:e49625. [PMID: 23166731 PMCID: PMC3498225 DOI: 10.1371/journal.pone.0049625] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 10/11/2012] [Indexed: 11/24/2022] Open
Abstract
Outer membrane protein A (OmpA) is a multifaceted predominant outer membrane protein of Escherichia coli and other Enterobacteriaceae whose role in the pathogenesis of various bacterial infections has recently been recognized. Here, the role of OmpA on the virulence of Shigella flexneri has been investigated. An ompA mutant of wild-type S. flexneri 5a strain M90T was constructed (strain HND92) and it was shown to be severely impaired in cell-to-cell spreading since it failed to plaque on HeLa cell monolayers. The lack of OmpA significantly reduced the levels of IcsA while the levels of cell associated and released IcsP-cleaved 95 kDa amino-terminal portion of the mature protein were similar. Nevertheless, the ompA mutant displayed IcsA exposed across the entire bacterial surface. Surprisingly, the ompA mutant produced proper F-actin comet tails, indicating that the aberrant IcsA exposition at bacterial lateral surface did not affect proper activation of actin-nucleating proteins, suggesting that the absence of OmpA likely unmasks mature or cell associated IcsA at bacterial lateral surface. Moreover, the ompA mutant was able to invade and to multiply within HeLa cell monolayers, although internalized bacteria were found to be entrapped within the host cell cytoplasm. We found that the ompA mutant produced significantly less protrusions than the wild-type strain, indicating that this defect could be responsible of its inability to plaque. Although we could not definitely rule out that the ompA mutation might exert pleiotropic effects on other S. flexneri genes, complementation of the ompA mutation with a recombinant plasmid carrying the S. flexneri ompA gene clearly indicated that a functional OmpA protein is required and sufficient for proper IcsA exposition, plaque and protrusion formation. Moreover, an independent ompA mutant was generated. Since we found that both mutants displayed identical virulence profile, these results further supported the findings presented in this study.
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Affiliation(s)
- Cecilia Ambrosi
- Dip. di Scienze Sperimentali e Cliniche, Università “G. D’Annunzio’ di Chieti, Chieti, Italy
| | - Monica Pompili
- Dip. di Sanità Pubblica e Malattie Infettive Università “Sapienza” di Roma, Rome, Italy
| | | | - Carlo Zagaglia
- Dip. di Sanità Pubblica e Malattie Infettive Università “Sapienza” di Roma, Rome, Italy
| | - Sandro Ripa
- Dip. di Biologia Molecolare, Cellulare e Animale Università di Camerino, Camerino (MC), Italy
| | - Mauro Nicoletti
- Dip. di Scienze Sperimentali e Cliniche, Università “G. D’Annunzio’ di Chieti, Chieti, Italy
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Fu H, Liu L, Zhang X, Zhu Y, Zhao L, Peng J, He H, Jin Q. Common changes in global gene expression induced by RNA polymerase inhibitors in Shigella flexneri. PLoS One 2012; 7:e33240. [PMID: 22428000 PMCID: PMC3299763 DOI: 10.1371/journal.pone.0033240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Accepted: 02/06/2012] [Indexed: 11/22/2022] Open
Abstract
Characterization of expression profile of organisms in response to antimicrobials provides important information on the potential mechanism of action of the drugs. The special expression signature can be used to predict whether other drugs act on the same target. Here, the common response of Shigella flexneri to two inhibitors of RNA polymerase was examined using gene expression profiling. Consistent with similar effects of the two drugs, the gene expression profiles indicated that responses of the bacteria to these drugs were roughly the same, with 225 genes affected commonly. Of them, 88 were induced and 137 were repressed. Real-time PCR was performed for selected genes to verify the microarray results. Analysis of the expression data revealed that more than 30% of the plasmid-encoded genes on the array were up-regulated by the antibiotics including virF regulon, other virulence-related genes, and genes responsible for plasmid replication, maintenance, and transfer. In addition, some chromosome-encoded genes involved in virulence and genes acquired from horizontal transfer were also significantly up-regulated. However, the expression of genes encoding the beta-subunit of RNA polymerase was increased moderately. The repressed genes include those that code for products associated with the ribosome, citrate cycle, glycolysis, thiamine biosynthesis, purine metabolism, fructose metabolism, mannose metabolism, and cold shock proteins. This study demonstrates that the two antibiotics induce rapid cessation of RNA synthesis resulting in inhibition of translation components. It also indicates that the production of virulence factors involved in intercellular dissemination, tissue invasion and inflammatory destruction may be enhanced through derepressing horizontal transfer genes by the drugs.
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Affiliation(s)
- Hua Fu
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People's Republic of China
| | - Liguo Liu
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People's Republic of China
- National Research Center for Wildlife Born Diseases, Institute of Zoology, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Xiaobing Zhang
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People's Republic of China
| | - Yafang Zhu
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People's Republic of China
| | - Lina Zhao
- Department of Biological Engineering, College of Life Sciences, Hebei United University, Hebei, People's Republic of China
| | - Junping Peng
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People's Republic of China
| | - Hongxuan He
- National Research Center for Wildlife Born Diseases, Institute of Zoology, Chinese Academy of Sciences, Beijing, People's Republic of China
- * E-mail: (HH); (QJ)
| | - Qi Jin
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People's Republic of China
- * E-mail: (HH); (QJ)
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Cai X, Zhang J, Chen M, Wu Y, Wang X, Chen J, Zhang J, Shen X, Qu D, Jiang H. The effect of the potential PhoQ histidine kinase inhibitors on Shigella flexneri virulence. PLoS One 2011; 6:e23100. [PMID: 21853073 PMCID: PMC3154276 DOI: 10.1371/journal.pone.0023100] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Accepted: 07/11/2011] [Indexed: 02/03/2023] Open
Abstract
PhoQ/PhoP is an important two-component system that regulates Shigella virulence. We explored whether the PhoQ/PhoP system is a promising target for new antibiotics against S. flexneri infection. By using a high-throughput screen and enzymatic activity coupled assay, four compounds were found as potential PhoQ inhibitors. These compounds not only inhibited the activity of SF-PhoQc autophosphorylation but also displayed high binding affinities to the SF-PhoQc protein in the Surface Plasmon Resonance response. A S. flexneri cell invasion assay showed that three of these potential PhoQ inhibitors inhibit the invasion of HeLa cells by S. flexneri 9380. In a Mouse Sereny test, mice inoculated with S. flexneri 9380 pre-treated with the potential PhoQ inhibitors 1, 2, 3 or 4 displayed no inflammation, whereas mice inoculated with S. flexneri 9380 alone displayed severe keratoconjunctival inflammation. All four potential PhoQ inhibitors showed no significant cytotoxicity or hemolytic activity. These data suggest that the four potential PhoQ inhibitors inhibited the virulence of S. flexneri and that PhoQ/PhoP is a promising target for the development of drugs against S. flexneri infection.
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Affiliation(s)
- Xia Cai
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Institute of Medical Microbiology and Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Jian Zhang
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Mingliang Chen
- Shanghai Municipal Center for Disease Control and Prevention, Shanghai, China
| | - Yang Wu
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Institute of Medical Microbiology and Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Xueqing Wang
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Institute of Medical Microbiology and Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Jiayu Chen
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Institute of Medical Microbiology and Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Junqin Zhang
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Institute of Medical Microbiology and Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Xu Shen
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Di Qu
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Institute of Medical Microbiology and Institutes of Biomedical Sciences, Fudan University, Shanghai, China
- * E-mail: (DQ); (HJ)
| | - Hualiang Jiang
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
- * E-mail: (DQ); (HJ)
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Park H, Valencia-Gallardo C, Sharff A, Van Nhieu GT, Izard T. Novel vinculin binding site of the IpaA invasin of Shigella. J Biol Chem 2011; 286:23214-21. [PMID: 21525010 PMCID: PMC3123088 DOI: 10.1074/jbc.m110.184283] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2010] [Revised: 04/05/2011] [Indexed: 11/06/2022] Open
Abstract
Internalization of Shigella into host epithelial cells, where the bacteria replicates and spreads to neighboring cells, requires a type 3 secretion system (T3SS) effector coined IpaA. IpaA binds directly to and activates the cytoskeletal protein vinculin after injection in the host cell cytosol, and this was previously thought to be directed by two amphipathic α-helical vinculin-binding sites (VBS) found in the C-terminal tail domain of IpaA. Here, we report a third VBS, IpaA-VBS3, that is located N-terminal to the other two VBSs of IpaA and show that one IpaA molecule can bind up to three vinculin molecules. Biochemical in vitro Shigella invasion assays and the 1.6 Å crystal structure of the vinculin·IpaA-VBS3 complex showed that IpaA-VBS3 is functionally redundant with the other two IpaA-VBSs in cell invasion and in activating the latent F-actin binding functions of vinculin. Multiple VBSs in IpaA are reminiscent of talin, which harbors 11 VBSs. However, most of the talin VBSs have low affinity and are buried in helix bundles, whereas all three of the VBSs of IpaA are high affinity, readily available, and in close proximity to each other in the IpaA structure. Although deletion of IpaA-VBS3 has no detectable effects on Shigella invasion of epithelial cells, deletion of all three VBSs impaired bacterial invasion to levels found in an ipaA null mutant strain. Thus, IpaA-directed mimicry of talin in activating vinculin occurs through three high affinity VBSs that are essential for Shigella pathogenesis.
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Affiliation(s)
- HaJeung Park
- From the Cell Adhesion Laboratory, Department of Cancer Biology, Scripps Research Institute, Jupiter, Florida 33458
| | - Cesar Valencia-Gallardo
- the Unité de Communication Intercellulaire et Infections Microbiennes, Inserm U971, Collège de France, 75005 Paris Cedex, France, and
| | - Andrew Sharff
- Global Phasing Ltd., Sheraton House, Castle Park, Cambridge CB3 0AX, United Kingdom
| | - Guy Tran Van Nhieu
- the Unité de Communication Intercellulaire et Infections Microbiennes, Inserm U971, Collège de France, 75005 Paris Cedex, France, and
| | - Tina Izard
- From the Cell Adhesion Laboratory, Department of Cancer Biology, Scripps Research Institute, Jupiter, Florida 33458
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Mostowy S, Bonazzi M, Hamon MA, Tham TN, Mallet A, Lelek M, Gouin E, Demangel C, Brosch R, Zimmer C, Sartori A, Kinoshita M, Lecuit M, Cossart P. Entrapment of intracytosolic bacteria by septin cage-like structures. Cell Host Microbe 2011; 8:433-44. [PMID: 21075354 DOI: 10.1016/j.chom.2010.10.009] [Citation(s) in RCA: 190] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Revised: 09/23/2010] [Accepted: 10/07/2010] [Indexed: 11/16/2022]
Abstract
Actin-based motility is used by various pathogens for dissemination within and between cells. Yet host factors restricting this process have not been identified. Septins are GTP-binding proteins that assemble as filaments and are essential for cell division. However, their role during interphase has remained elusive. Here, we report that septin assemblies are recruited to different bacteria that polymerize actin. We observed that intracytosolic Shigella either become compartmentalized in septin cage-like structures or form actin tails. Inactivation of septin caging increases the number of Shigella with actin tails and enhances cell-to-cell spread. TNF-α, a host cytokine produced upon Shigella infection, stimulates septin caging and restricts actin tail formation and cell-to-cell spread. Finally, we show that septin cages entrap bacteria targeted to autophagy. Together, these results reveal an unsuspected mechanism of host defense that restricts dissemination of invasive pathogens.
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Affiliation(s)
- Serge Mostowy
- Unité des Interactions Bactéries-Cellules, Institut Pasteur, Paris F-75015, France.
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Hensley CT, Kamneva OK, Levy KM, Labahn SK, Africa LA, Wing HJ. Two promoters and two translation start sites control the expression of the Shigella flexneri outer membrane protease IcsP. Arch Microbiol 2011; 193:263-74. [PMID: 21225241 DOI: 10.1007/s00203-010-0669-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 12/10/2010] [Accepted: 12/15/2010] [Indexed: 11/26/2022]
Abstract
The Shigella flexneri outer membrane protease IcsP proteolytically cleaves the actin-based motility protein IcsA from the bacterial surface. The icsP gene is monocistronic and lies downstream of an unusually large intergenic region on the Shigella virulence plasmid. In silico analysis of this region predicts a second transcription start site 84 bp upstream of the first. Primer extension analyses and beta-galactosidase assays demonstrate that both transcription start sites are used. Both promoters are regulated by the Shigella virulence gene regulator VirB and both respond similarly to conditions known to influence Shigella virulence gene expression (iron concentration, pH, osmotic pressure, and phase of growth). The newly identified promoter lies upstream of a Shine-Dalgarno sequence and second 5'-ATG-3', which is in frame with the annotated icsP gene. The use of either translation start site leads to the production of IcsP capable of proteolytically cleaving IcsA. A bioinformatic scan of the Shigella genome reveals multiple occurrences of in-frame translation start sites associated with putative Shine-Dalgarno sequences, immediately upstream and downstream of annotated open reading frames. Taken together, our observations support the possibility that the use of in-frame translation start sites may generate different protein isoforms, thereby expanding the proteome encoded by bacterial genomes.
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Affiliation(s)
- Christopher T Hensley
- School of Life Sciences, University of Nevada, 4505 Maryland Parkway, Las Vegas, NV, 89154-4004, USA
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Birdi T, Daswani P, Brijesh S, Tetali P, Natu A, Antia N. Newer insights into the mechanism of action of Psidium guajava L. leaves in infectious diarrhoea. BMC Complement Altern Med 2010; 10:33. [PMID: 20584265 PMCID: PMC2911405 DOI: 10.1186/1472-6882-10-33] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Accepted: 06/28/2010] [Indexed: 11/20/2022]
Abstract
BACKGROUND Psidium guajava L., Myrtaceae, is used widely in traditional medicine for the treatment of diarrhoea, dysentery, gastroenteritis, stomachaches, and indigestion. However, the effect of the leaf extract of P. guajava on the pathogenesis of infectious diarrhoea has not been studied. The present study evaluates the effect of a hot aqueous extract (decoction) of dried leaves of P. guajava on parameters associated with pathogenicity of infectious diarrhoea. The aim was to understand its possible mechanism(s) of action in controlling infectious diarrhoea and compare it with quercetin, one of the most reported active constituents of P. guajava with antidiarrhoeal activity. METHODS The crude decoction and quercetin were studied for their antibacterial activity and effect on virulence features of common diarrhoeal pathogens viz. colonization of epithelial cells and production and action of enterotoxins. Colonization as measured by adherence of enteropathogenic Escherichia coli (EPEC) and invasion of enteroinvasive E. coli (EIEC) and Shigella flexneri was assessed using HEp-2 cell line. The production of E. coli heat labile toxin (LT) and cholera toxin (CT) and their binding to ganglioside monosialic acid (GM1) were studied by GM1-ELISA whereas the production and action of E. coli heat stable toxin (ST) was assessed by suckling mouse assay. RESULTS The decoction of P. guajava showed antibacterial activity towards S. flexneri and Vibrio cholerae. It decreased production of both LT and CT and their binding to GM1. However, it had no effect on production and action of ST. The decoction also inhibited the adherence of EPEC and invasion by both EIEC and S. flexneri to HEp-2 cells. Quercetin, on the other hand, had no antibacterial activity at the concentrations used nor did it affect any of the enterotoxins. Although it did not affect adherence of EPEC, it inhibited the invasion of both EIEC and S. flexneri to HEp-2 cells. CONCLUSION Collectively, the results indicate that the decoction of P. guajava leaves is an effective antidiarrhoeal agent and that the entire spectrum of its antidiarrhoeal activity is not due to quercetin alone.
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Affiliation(s)
- Tannaz Birdi
- The Foundation for Medical Research, 84A, RG Thadani Marg, Worli, Mumbai 400018, Maharashtra, India
| | - Poonam Daswani
- The Foundation for Medical Research, 84A, RG Thadani Marg, Worli, Mumbai 400018, Maharashtra, India
| | - S Brijesh
- The Foundation for Medical Research, 84A, RG Thadani Marg, Worli, Mumbai 400018, Maharashtra, India
| | - Pundarikakshudu Tetali
- Naoroji Godrej Centre for Plant Research, Lawkin Ltd. Campus, Shindewadi, Shirwal, Satara 412801, Maharashtra, India
| | - Arvind Natu
- Indian Institute of Science Education and Research, Central Tower, Sai Trinity, Garware Circle, Sutarwadi, Pashan, Pune 411021, Maharashtra, India
| | - Noshir Antia
- The Foundation for Medical Research, 84A, RG Thadani Marg, Worli, Mumbai 400018, Maharashtra, India
- The Foundation for Research in Community Health, 3-4, Trimiti-B Apartments, 85, Anand Park, Pune 411 007, Maharashtra, India
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Zhu L, Zhao G, Stein R, Zheng X, Hu W, Shang N, Bu X, Liu X, Wang J, Feng E, Wang B, Zhang X, Ye Q, Huang P, Zeng M, Wang H. The proteome of Shigella flexneri 2a 2457T grown at 30 and 37 degrees C. Mol Cell Proteomics 2010; 9:1209-20. [PMID: 20164057 PMCID: PMC2877981 DOI: 10.1074/mcp.m900446-mcp200] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Revised: 02/10/2010] [Indexed: 01/19/2023] Open
Abstract
To upgrade the proteome reference map of Shigella flexneri 2a 2457T, the protein expression profiles of log phase and stationary phase cells grown at 30 and 37 degrees C were thoroughly analyzed using multiple overlapping narrow pH range (between pH 4.0 and 11.0) two-dimensional gel electrophoresis. A total of 723 spots representing 574 protein entries were identified by MALDI-TOF/TOF MS, including the majority of known key virulence factors. 64 hypothetical proteins and six misannotated proteins were also experimentally identified. A comparison between the four proteome maps showed that most of the virulence-related proteins were up-regulated at 37 degrees C, and the differences were more notable in stationary phase cells, suggesting that the expressions of these virulence factors were not only controlled by temperature but also controlled by the nutrients available in the environment. The expression patterns of some virulence-related genes under the four different conditions suggested that they might also be regulated at the post-transcriptional level. A further significant finding was that the expression of the protein ArgT was dramatically up-regulated at 30 degrees C. The results of semiquantitative RT-PCR analysis showed that expression of argT was not regulated at the transcriptional level. Therefore, we carried out a series of experiments to uncover the mechanism regulating ArgT levels and found that the differential expression of ArgT was due to its degradation by a periplasmic protease, HtrA, whose activity, but not its synthesis, was affected by temperature. The cleavage site in ArgT was between position 160 (Val) and position 161 (Ala). These results may provide useful insights for understanding the physiology and pathogenesis of S. flexneri.
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Affiliation(s)
- Li Zhu
- From the ‡Beijing Institute of Biotechnology, State Key Laboratory of Pathogen and Biosecurity, 100071 Beijing, China
| | - Ge Zhao
- From the ‡Beijing Institute of Biotechnology, State Key Laboratory of Pathogen and Biosecurity, 100071 Beijing, China
- ¶Shandong Eye Institute, 266071 Qingdao, China
| | - Robert Stein
- ‖Informatics and Biology, D-12169 Berlin, Germany
| | - Xuexue Zheng
- From the ‡Beijing Institute of Biotechnology, State Key Laboratory of Pathogen and Biosecurity, 100071 Beijing, China
| | - Wei Hu
- From the ‡Beijing Institute of Biotechnology, State Key Laboratory of Pathogen and Biosecurity, 100071 Beijing, China
| | - Na Shang
- From the ‡Beijing Institute of Biotechnology, State Key Laboratory of Pathogen and Biosecurity, 100071 Beijing, China
| | - Xin Bu
- From the ‡Beijing Institute of Biotechnology, State Key Laboratory of Pathogen and Biosecurity, 100071 Beijing, China
| | - Xiankai Liu
- From the ‡Beijing Institute of Biotechnology, State Key Laboratory of Pathogen and Biosecurity, 100071 Beijing, China
| | - Jie Wang
- **National Center of Biomedical Analysis, 100850 Beijing, China
| | - Erling Feng
- From the ‡Beijing Institute of Biotechnology, State Key Laboratory of Pathogen and Biosecurity, 100071 Beijing, China
| | - Bin Wang
- ‡‡National Institute for the Control of Pharmaceutical and Biological Products, 100050 Beijing, China, and
| | - Xuemin Zhang
- **National Center of Biomedical Analysis, 100850 Beijing, China
| | - Qinong Ye
- From the ‡Beijing Institute of Biotechnology, State Key Laboratory of Pathogen and Biosecurity, 100071 Beijing, China
| | - Peitang Huang
- From the ‡Beijing Institute of Biotechnology, State Key Laboratory of Pathogen and Biosecurity, 100071 Beijing, China
| | - Ming Zeng
- ‡‡National Institute for the Control of Pharmaceutical and Biological Products, 100050 Beijing, China, and
| | - Hengliang Wang
- From the ‡Beijing Institute of Biotechnology, State Key Laboratory of Pathogen and Biosecurity, 100071 Beijing, China
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Giangrossi M, Prosseda G, Tran CN, Brandi A, Colonna B, Falconi M. A novel antisense RNA regulates at transcriptional level the virulence gene icsA of Shigella flexneri. Nucleic Acids Res 2010; 38:3362-75. [PMID: 20129941 PMCID: PMC2879508 DOI: 10.1093/nar/gkq025] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2009] [Revised: 12/30/2009] [Accepted: 01/11/2010] [Indexed: 12/26/2022] Open
Abstract
The virulence gene icsA of Shigella flexneri encodes an invasion protein crucial for host colonization by pathogenic bacteria. Within the intergenic region virA-icsA, we have discovered a new gene that encodes a non-translated antisense RNA (named RnaG), transcribed in cis on the complementary strand of icsA. In vitro transcription assays show that RnaG promotes premature termination of transcription of icsA mRNA. Transcriptional inhibition is also observed in vivo by monitoring the expression profile in Shigella by real-time polymerase chain reaction and when RnaG is provided in trans. Chemical and enzymatic probing of the leader region of icsA mRNA either free or bound to RnaG indicate that upon hetero-duplex formation an intrinsic terminator, leading to transcription block, is generated on the nascent icsA mRNA. Mutations in the hairpin structure of the proposed terminator impair the RnaG mediated-regulation of icsA transcription. This study represents the first evidence of transcriptional attenuation mechanism caused by a small RNA in Gram-negative bacteria. We also present data on the secondary structure of the antisense region of RnaG. In addition, alternatively silencing icsA and RnaG promoters, we find that transcription from the strong RnaG promoter reduces the activity of the weak convergent icsA promoter through the transcriptional interference regulation.
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Affiliation(s)
- Mara Giangrossi
- Laboratory of Molecular Genetics, Department of Biology MCA, University of Camerino, 62032 Camerino, MC, Italy
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38
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Newton HJ, Pearson JS, Badea L, Kelly M, Lucas M, Holloway G, Wagstaff KM, Dunstone MA, Sloan J, Whisstock JC, Kaper JB, Robins-Browne RM, Jans DA, Frankel G, Phillips AD, Coulson BS, Hartland EL. The type III effectors NleE and NleB from enteropathogenic E. coli and OspZ from Shigella block nuclear translocation of NF-kappaB p65. PLoS Pathog 2010; 6:e1000898. [PMID: 20485572 PMCID: PMC2869321 DOI: 10.1371/journal.ppat.1000898] [Citation(s) in RCA: 183] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Accepted: 04/05/2010] [Indexed: 11/19/2022] Open
Abstract
Many bacterial pathogens utilize a type III secretion system to deliver multiple effector proteins into host cells. Here we found that the type III effectors, NleE from enteropathogenic E. coli (EPEC) and OspZ from Shigella, blocked translocation of the p65 subunit of the transcription factor, NF-kappaB, to the host cell nucleus. NF-kappaB inhibition by NleE was associated with decreased IL-8 expression in EPEC-infected intestinal epithelial cells. Ectopically expressed NleE also blocked nuclear translocation of p65 and c-Rel, but not p50 or STAT1/2. NleE homologues from other attaching and effacing pathogens as well OspZ from Shigella flexneri 6 and Shigella boydii, also inhibited NF-kappaB activation and p65 nuclear import; however, a truncated form of OspZ from S. flexneri 2a that carries a 36 amino acid deletion at the C-terminus had no inhibitory activity. We determined that the C-termini of NleE and full length OspZ were functionally interchangeable and identified a six amino acid motif, IDSY(M/I)K, that was important for both NleE- and OspZ-mediated inhibition of NF-kappaB activity. We also established that NleB, encoded directly upstream from NleE, suppressed NF-kappaB activation. Whereas NleE inhibited both TNFalpha and IL-1beta stimulated p65 nuclear translocation and IkappaB degradation, NleB inhibited the TNFalpha pathway only. Neither NleE nor NleB inhibited AP-1 activation, suggesting that the modulatory activity of the effectors was specific for NF-kappaB signaling. Overall our data show that EPEC and Shigella have evolved similar T3SS-dependent means to manipulate host inflammatory pathways by interfering with the activation of selected host transcriptional regulators.
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Affiliation(s)
- Hayley J. Newton
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
| | - Jaclyn S. Pearson
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
| | - Luminita Badea
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
| | - Michelle Kelly
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
| | - Mark Lucas
- Centre for Pediatric Gastroenterology, UCL Medical School, Royal Free Campus, London, United Kingdom
| | - Gavan Holloway
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
| | - Kylie M. Wagstaff
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Michelle A. Dunstone
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Joan Sloan
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
| | - James C. Whisstock
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
- ARC Centre for Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria, Australia
| | - James B. Kaper
- Centre for Vaccine Development and Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Roy M. Robins-Browne
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
| | - David A. Jans
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Gad Frankel
- Centre for Molecular Microbiology and Infection, Division of Cell and Molecular Biology, Imperial College London, London, United Kingdom
| | - Alan D. Phillips
- Centre for Pediatric Gastroenterology, UCL Medical School, Royal Free Campus, London, United Kingdom
| | - Barbara S. Coulson
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
| | - Elizabeth L. Hartland
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
- * E-mail:
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Baghal SML, Gargari SLM, Rasooli I. Production and immunogenicity of recombinant ferric enterobactin protein (FepA). Int J Infect Dis 2010; 14 Suppl 3:e166-70. [PMID: 20418143 DOI: 10.1016/j.ijid.2009.12.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Revised: 12/18/2009] [Accepted: 12/20/2009] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVES Ferric siderophore complexes are produced by most bacteria to acquire iron, a vital element. These complexes are transported across the outer membrane by receptor proteins commonly known as FepA (ferric enterobactin protein). In this study we attempted to evaluate the immunogenicity of the membrane protein FepA, aiming at inhibition of iron uptake to protect invasion of the host by the bacterium. METHODS The genomic fepA gene was amplified from Escherichia coli O157:H7. The PCR product was ligated into pET28a and was then expressed in E. coli BL21(DE3). The recombinant protein purified by nickel-nitrilotriacetic acid (Ni-NTA) affinity chromatography was injected into BALB/C mice to induce immunity. Antibody titer was determined by ELISA. Mouse groups were challenged with various doses of E. coli O157:H7, Shigella flexneri, Klebsiella pneumoniae, and Salmonella typhi to study immune response. RESULTS An 85-kDa recombinant protein was expressed and purified. Immunogenicity of the recombinant protein was determined by injecting BALB/C mice. The antibody produced therein could efficiently recognize and bind ferric enterobactin binding protein. Immunized mice challenged with higher doses of selected bacteria survived. CONCLUSIONS Significant recognition by the antibody of ferric enterobactin binding protein may lead to its application in the restriction of Enterobacteriaceae propagation.
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Abstract
Shigella flexneri and other invasive bacteria rupture the phagosome membrane and escape to the host cytoplasm. Now, Dupont et al. address the fate and signaling functions of pathogen vacuole remnants and show that these membrane fragments trigger host-cell-signaling responses, including polyubiquitination, autophagy, and pyroptosis.
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Affiliation(s)
- Hubert Hilbi
- Institute of Zoology, University of Zurich, Winterthurerstrasse 190, Zurich CH-8057, Switzerland.
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41
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Mounier J, Popoff MR, Enninga J, Frame MC, Sansonetti PJ, Van Nhieu GT. The IpaC carboxyterminal effector domain mediates Src-dependent actin polymerization during Shigella invasion of epithelial cells. PLoS Pathog 2009; 5:e1000271. [PMID: 19165331 PMCID: PMC2621354 DOI: 10.1371/journal.ppat.1000271] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Accepted: 12/15/2008] [Indexed: 01/04/2023] Open
Abstract
Shigella, the causative agent of bacillary dysentery, invades epithelial cells by locally reorganizing the actin cytoskeleton. Shigella invasion requires actin polymerization dependent on the Src tyrosine kinase and a functional bacterial type III secretion (T3S) apparatus. Using dynamic as well as immunofluorescence microscopy, we show that the T3S translocon component IpaC allows the recruitment of the Src kinase required for actin polymerization at bacterial entry sites during the initial stages of Shigella entry. Src recruitment occurred at bacterial-cell contact sites independent of actin polymerization at the onset of the invasive process and was still observed in Shigella strains mutated for translocated T3S effectors of invasion. A Shigella strain with a polar mutation that expressed low levels of the translocator components IpaB and IpaC was fully proficient for Src recruitment and bacterial invasion. In contrast, a Shigella strain mutated in the IpaC carboxyterminal effector domain that was proficient for T3S effector translocation did not induce Src recruitment. Consistent with a direct role for IpaC in Src activation, cell incubation with the IpaC last 72 carboxyterminal residues fused to the Iota toxin Ia (IaC) component that translocates into the cell cytosol upon binding to the Ib component led to Src-dependent ruffle formation. Strikingly, IaC also induced actin structures resembling bacterial entry foci that were enriched in activated Src and were inhibited by the Src inhibitor PP2. These results indicate that the IpaC effector domain determines Src-dependent actin polymerization and ruffle formation during bacterial invasion. Type III secretion systems (T3SS) are present in a wide range of Gram-negative bacteria that are pathogenic to humans, animals, and plants. These molecular devices allow the injection of bacterial virulence factors into host cells to manipulate various cellular functions. T3SSs share similar functional features. Noticeably, host cell contact triggers the secretion of two T3SS substrates that insert into host cell membranes to form a so-called “translocator” required for the injection of T3SS effectors. Shigella, an enteroinvasive pathogen responsible for bacillary dysentery, uses a T3SS to transiently reorganize the actin cytoskeleton and to induce its internalization into epithelial cells. Some Shigella-injected T3SS effectors participate in cytoskeletal reorganization, but none of these effectors are totally necessary or sufficient to induce bacterial invasion. We show here that in addition to its role in the injection of bacterial effectors, the translocator component IpaC also induces the recruitment of Src and actin polymerization driving the formation of localized membrane ruffling. Our findings suggest that major signaling through T3S translocator components occurs during the initial steps of bacterial interaction with host cell membranes. Compounds that prevent membrane insertion of the Shigella T3S translocator would likely constitute ideal candidates for antimicrobial agents.
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Affiliation(s)
- Joëlle Mounier
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, Paris, France
- Inserm U786, Institut Pasteur, Paris, France
| | - Michel R. Popoff
- Unité de Recherche et d'Expertise Bactéries anaérobies et Toxines, Institut Pasteur, Paris, France
| | - Jost Enninga
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, Paris, France
- Inserm U786, Institut Pasteur, Paris, France
| | - Margaret C. Frame
- Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh Cancer Research Centre, Western General Hospital, Edinburgh, United Kingdom
| | - Philippe J. Sansonetti
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, Paris, France
- Inserm U786, Institut Pasteur, Paris, France
| | - Guy Tran Van Nhieu
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, Paris, France
- Inserm U786, Institut Pasteur, Paris, France
- * E-mail:
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Fukazawa A, Alonso C, Kurachi K, Gupta S, Lesser CF, McCormick BA, Reinecker HC. GEF-H1 mediated control of NOD1 dependent NF-kappaB activation by Shigella effectors. PLoS Pathog 2008; 4:e1000228. [PMID: 19043560 PMCID: PMC2583055 DOI: 10.1371/journal.ppat.1000228] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Accepted: 11/04/2008] [Indexed: 02/07/2023] Open
Abstract
Shigella flexneri has evolved the ability to modify host cell function with intracellular active effectors to overcome the intestinal barrier. The detection of these microbial effectors and the initiation of innate immune responses are critical for rapid mucosal defense activation. The guanine nucleotide exchange factor H1 (GEF-H1) mediates RhoA activation required for cell invasion by the enteroinvasive pathogen Shigella flexneri. Surprisingly, GEF-H1 is requisite for NF-κB activation in response to Shigella infection. GEF-H1 interacts with NOD1 and is required for RIP2 dependent NF-κB activation by H-Ala-D-γGlu-DAP (γTriDAP). GEF-H1 is essential for NF-κB activation by the Shigella effectors IpgB2 and OspB, which were found to signal in a NOD1 and RhoA Kinase (ROCK) dependent manner. Our results demonstrate that GEF-H1 is a critical component of cellular defenses forming an intracellular sensing system with NOD1 for the detection of microbial effectors during cell invasion by pathogens. Shigella is a bacterium that causes food poisoning and serious intestinal infections with diarrheal illness. Pathogens like Shigella utilize intracellular active effectors to overcome the intestinal barrier and invade the host. We demonstrate that intestinal epithelial cells can sense the disturbance of the tight junctional seal, which normally prevents access of microbes to the circulation. A signaling molecule, which is required for cell invasion by Shigella, also activates messengers that activate immune defenses. This pathway of intestinal pathogen detection is activated by Shigella products, which are injected into host cells by the pathogen and depends on intracellular microbial recognition receptors. The detection of altered cellular function by bacterial effectors may be important for the ability to rapidly respond to barrier disruption in the intestine with the attraction and activation of immune cells to defend against the intruders.
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Affiliation(s)
- Atsuko Fukazawa
- Department of Medicine, Gastrointestinal Unit and Center for the Study of Inflammatory Bowel Disease, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Carmen Alonso
- Department of Medicine, Gastrointestinal Unit and Center for the Study of Inflammatory Bowel Disease, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Kiyotaka Kurachi
- Department of Medicine, Gastrointestinal Unit and Center for the Study of Inflammatory Bowel Disease, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sonal Gupta
- Department of Medicine, Gastrointestinal Unit and Center for the Study of Inflammatory Bowel Disease, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Cammie F. Lesser
- Department of Microbiology and Molecular Genetics and Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Beth Ann McCormick
- Department of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Hans-Christian Reinecker
- Department of Medicine, Gastrointestinal Unit and Center for the Study of Inflammatory Bowel Disease, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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43
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Formal SB, Gemski P, Giannella RA, Takeuchi A. Studies on the pathogenesis of enteric infections caused by invasive bacteria. Ciba Found Symp 2008:27-43. [PMID: 62646 DOI: 10.1002/9780470720240.ch3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Salmonellae, shigellae and some Escherichia coli must invade the intestinal epithelial cell and multiply within the mucosa to cause disease. Although the bacterial cell most likely possesses several properties essential to this invasive ability, the nature of the cell envelope complex is at present the only characteristic which has been implicated in this process. While a number of pathophysiological events result from invasion, some of our recent efforts have concerned the site and mechanism of intestinal fluid loss in salmonellosis and shigellosis. In both these disorders, bacterial invasion of the colonic mucosa, associated with an acute inflammatory reaction and mucosal damage, is regularly seen and colonic salt and water transport is abnormal. These defects may account for mild diarrhoea in salmonellosis and the dysenteric stools of shigellosis. However, in salmonella-infected animals with severe watery diarrhoea and in shigella-infected animals with diarrhoea alone or in combination with dysentery, the jejunum is in a net secretory state. This secretion occurs in the absence of bacterial invasion or morphological abnormalities. Thus, the diarrhoea caused by invasive bacteria may result from the inability of the colon to reabsorb the increased volume of fluid entering it from the small intestine. Although colonic mucosal damage is a feature of invasive-type diarrhoeas, the permeability of both the colon and small intestine to small molecules, mannitol and erythritol, is not altered. Thus intestinal fluid loss cannot be ascribed to transudation. In addition, the results of our Ussing chamber experiments, employing salmonella-infected rabbit ileum, reveal that salt and water secretion is an active process. Since secretion occurs in the jejunum in the absence of bacterial invasion, this might suggest the participation of an enterotoxin. Shigella dysenteriae I is the best-studied invasive organism in which an enterotoxin has been found, yet mutant strains which do not invade but retain the ability to elaborate enterotoxin fail to cause disease in either monkeys or man. Thus, the physiological relevance of Shiga enterotoxin and the mechanism of jejunal secretion in these disorders remain unclear. Recent data suggest that invasive enteropathogens, like the enterotoxin-producing bacteria, activate the mucosal adenylate cyclase-cyclic AMP system and that this activation may play a role in intestinal fluid secretion.
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Emch M, Ali M, Yunus M. Risk areas and neighborhood-level risk factors for Shigella dysenteriae 1 and Shigella flexneri. Health Place 2008; 14:96-105. [PMID: 17602851 DOI: 10.1016/j.healthplace.2007.05.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2006] [Revised: 04/27/2007] [Accepted: 05/15/2007] [Indexed: 10/23/2022]
Abstract
Annually, there are 165 million cases of shigellosis resulting in 1.1 million deaths in the developing world. Two species of the causative agent, Shigella dysenteriae 1 and Shigella flexneri, are responsible for acute diarrheal illness. Vaccines are being developed against both but many questions remain about the disease burden, distribution of species in space and time, and community-level risk factors. This study answers two questions. What are the differences in neighborhood-level risk factors between S. dysenteriae 1 and S. flexneri? Does shigellosis caused by the two different species occur in the same neighborhoods and are those high-risk neighborhoods persistent in time? Cases from a hospital in rural Bangladesh were assigned to one of the two shigellosis types and age-matched individuals were randomly chosen from the community to be controls. Information was collected for neighborhood-level variables hypothesized to be related to shigellosis. During the 3-year study period, there were 161 cases of S. dysenteriae 1 and 225 cases of S. flexneri. Incidence of both types was highest in children under 2 followed by children from 2 to 5. The location of S. dysenteriae 1 risk varies in time but S. flexneri risk areas were persistent in time. Neighborhoods near bazaars with many non-septic latrines were at highest risk for S. dysenteriae 1. S. flexneri was most common in flood-controlled areas. S. dysenteriae 1 risk is more related to hygiene and sanitation and S. flexneri is more related to the environment.
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Affiliation(s)
- Michael Emch
- University of North Carolina at Chapel Hill, Geography & CPC 308 Saunders Hall, Campus Box 3220, Chapel Hill, NC 27599, USA.
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45
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Leung Y, Ally S, Goldberg MB. Bacterial actin assembly requires toca-1 to relieve N-wasp autoinhibition. Cell Host Microbe 2008; 3:39-47. [PMID: 18191793 DOI: 10.1016/j.chom.2007.10.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Revised: 09/27/2007] [Accepted: 10/26/2007] [Indexed: 01/25/2023]
Abstract
Actin polymerization in the mammalian cytosol can be locally activated by mechanisms that relieve the autoinhibited state of N-WASP, an initiator of actin assembly, a process that also requires the protein Toca-1. Several pathogenic bacteria, including Shigella, exploit this host feature to infect and disseminate efficiently. The Shigella outer membrane protein IcsA recruits N-WASP, which upon activation at the bacterial surface mediates localized actin polymerization. The molecular role of Toca-1 in N-WASP activation during physiological or pathological actin assembly processes in intact mammalian cells remains unclear. We show that actin tail initiation by S. flexneri requires Toca-1 for the conversion of N-WASP from a closed inactive conformation to an open active one. While N-WASP recruitment is dependent on IcsA, Toca-1 recruitment is instead mediated by S. flexneri type III secretion effectors. Thus, S. flexneri independently hijacks two nodes of the N-WASP actin assembly pathway to initiate localized actin tail assembly.
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Affiliation(s)
- Yiuka Leung
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Cambridge, MA 02139, USA
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46
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Zhu L, Liu XK, Zhao G, Zhi YD, Bu X, Ying TY, Feng EL, Wang J, Zhang XM, Huang PT, Wang HL. Dynamic proteome changes of Shigella flexneri 2a during transition from exponential growth to stationary phase. Genomics Proteomics Bioinformatics 2007; 5:111-20. [PMID: 17893076 PMCID: PMC5054097 DOI: 10.1016/s1672-0229(07)60021-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Shigella flexneri is an infectious pathogen that causes dysentery to human, which remains a serious threat to public health, particularly in developing countries. In this study, the global protein expression patterns of S. flexneri during transition from exponential growth to stationary phase in vitro were analyzed by using 2-D PAGE combined with MALDI-TOF MS. In a time-course experiment with five time points, the relative abundance of 49 protein spots varied significantly. Interestingly, a putative outer membrane protein YciD (OmpW) was almost not detected in the exponential growth phase but became one of the most abundant proteins in the whole stationary-phase proteome. Some proteins regulated by the global regulator FNR were also significantly induced (such as AnsB, AspA, FrdAB, and KatG) or repressed (such as AceEF, OmpX, SodA, and SucAB) during the growth phase transition. These proteins may be the key effectors of the bacterial cell cycle or play important roles in the cellular maintenance and stress responses. Our expression profile data provide valuable information for the study of bacterial physiology and form the basis for future proteomic analyses of this pathogen.
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Affiliation(s)
- Li Zhu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing 100071, China
| | - Xian-Kai Liu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing 100071, China
| | - Ge Zhao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing 100071, China
| | - Yi-Dan Zhi
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing 100071, China
| | - Xin Bu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing 100071, China
| | - Tian-Yi Ying
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing 100071, China
| | - Er-Ling Feng
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing 100071, China
| | - Jie Wang
- National Center of Biomedical Analysis, Beijing 100850, China
| | - Xue-Min Zhang
- National Center of Biomedical Analysis, Beijing 100850, China
| | - Pei-Tang Huang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing 100071, China
- Corresponding authors.
| | - Heng-Liang Wang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing 100071, China
- Corresponding authors.
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47
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Prunier AL, Schuch R, Fernández RE, Mumy KL, Kohler H, McCormick BA, Maurelli AT. nadA and nadB of Shigella flexneri 5a are antivirulence loci responsible for the synthesis of quinolinate, a small molecule inhibitor of Shigella pathogenicity. Microbiology (Reading) 2007; 153:2363-2372. [PMID: 17600080 DOI: 10.1099/mic.0.2007/006916-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The evolution of bacterial pathogens from commensal organisms involves virulence gene acquisition followed by pathoadaptation to the new host, including inactivation of antivirulence loci (AVL). AVL are core ancestral genes whose expression is incompatible with the pathogenic lifestyle. Previous studies identified cadA (encoding lysine decarboxylase) as an AVL of Shigella spp. In this study, AVL of Shigella were identified by examining a phenotypic difference from its non-pathogenic ancestor, Escherichia coli. Unlike most E. coli strains, Shigella spp. are nicotinic acid auxotrophs, the pathway for the de novo synthesis of NAD being uniformly defective. In Shigella flexneri, this defect is due to alterations in the nadA and/or nadB genes encoding the enzyme complex that converts L-aspartate to quinolinate, a precursor to NAD synthesis. Quinolinate was found to inhibit invasion and cell-to-cell spread of Sh. flexneri 5a and its ability to induce polymorphonuclear neutrophil transepithelial migration. Virulence of other Shigella species was also inhibited by quinolinate. Introduction of functional nadA and nadB genes from E. coli K-12 into Sh. flexneri 5a restored its ability to synthesize quinolinate but also resulted in strong attenuation of virulence in this strain. The results define nadA and nadB as AVL in Shigella and validate the concept of pathoadaptive evolution of bacteria from commensal ancestors by inactivation of AVL. They also suggest that studies focusing on this form of bacterial evolution can identify novel inhibitors of virulence in other bacterial pathogens.
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Affiliation(s)
- Anne-Laure Prunier
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD 20814-4799, USA
| | - Raymond Schuch
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD 20814-4799, USA
| | - Reinaldo E Fernández
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD 20814-4799, USA
| | - Karen L Mumy
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, MA 02115, USA
- Mucosal Immunology Laboratory, Department of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | - Henrik Kohler
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, MA 02115, USA
- Mucosal Immunology Laboratory, Department of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | - Beth A McCormick
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, MA 02115, USA
- Mucosal Immunology Laboratory, Department of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | - Anthony T Maurelli
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD 20814-4799, USA
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Schroeder GN, Jann NJ, Hilbi H. Intracellular type III secretion by cytoplasmic Shigella flexneri promotes caspase-1-dependent macrophage cell death. Microbiology (Reading) 2007; 153:2862-2876. [PMID: 17768231 DOI: 10.1099/mic.0.2007/007427-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The Gram-negative bacterium Shigella flexneri triggers pro-inflammatory apoptotic cell death in macrophages, which is crucial for the onset of an acute inflammatory diarrhoea termed bacillary dysentery. The Mxi-Spa type III secretion system promotes bacterial uptake and escape into the cytoplasm, where, dependent on the translocator/effector protein IpaB, caspase-1 [interleukin (IL)-1beta-converting enzyme] and its substrate IL-1beta are activated. Here, we show that in the course of a macrophage infection, IpaB is secreted intracellularly for more than 1 h post-infection and progressively accumulates in aggregates on the bacterial surface. Concomitantly, the bacterial pool of IpaB is gradually depleted. The protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) dose-dependently inhibited the Mxi-Spa-dependent secretion of IpaB triggered by the dye Congo red in vitro and abolished translocation of IpaB into the host-cell cytoplasm of S. flexneri-infected macrophages. CCCP specifically inhibited S. flexneri-triggered macrophage death in a dose-dependent manner, even if added up to 60 min post-infection. Addition of CCCP 15 min after infection blocked macrophage cell death, the activation of caspase-1 and the maturation of IL-1beta, without affecting uptake or escape of S. flexneri from the phagosome. By contrast, CCCP used at the same concentration had no effect on ATP-induced caspase-1 activation or staurosporine-induced apoptosis. Our results indicate that under the conditions used, CCCP rapidly and specifically blocks bacterial type III secretion, and thus, intracellular type III secretion promotes cytotoxicity of S. flexneri.
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Affiliation(s)
- Gunnar N Schroeder
- Institute of Microbiology, Swiss Federal Institute of Technology (ETH) Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland
| | - Naja J Jann
- Institute of Microbiology, Swiss Federal Institute of Technology (ETH) Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland
| | - Hubert Hilbi
- Institute of Microbiology, Swiss Federal Institute of Technology (ETH) Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland
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Huang LY, Shi ZX, Yuan J, Hu FQ. [Expression profile analysis of host HeLa cells invasived by Shigella flexneri 2a]. Wei Sheng Wu Xue Bao 2007; 47:810-816. [PMID: 18062254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The changes of genes expression in HeLa cell during the invasion with Shigella species for 1h and 3h were analyzed by cDNA microarrays. The data showed that the expression levels of 752 genes were altered twice or greater as compared with the control 509 of them were up-regulated, and 306 were down-regulated. It was supposed that some signal pathways in HeLa cell were activated, then many genes were induced, and at last comprehensive cell responses were produced, so that HeLa cell could prevent against Shigella species infection. Two striking difference cDNA fragments TNFR 1B and ERBB2, which were up-regulated in the host epithelial cell during Shigella infection, analyzed expression by real time RT-PCR as determined by cDNA arrays. We suggested they play important roles in response to the invasive S. flexneri 2457T. Based on the results of gene expression alterations, the molecular pathogenic mechanism of Shigella species could be greatly and deeply understood, and the strategy for prevention against and treatment for shigellosis would be formed.
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Affiliation(s)
- Liu-Yu Huang
- Department of Microbiology, Third Military Medical University, Chongqing 400038, China.
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Núñez-Samudio V, Landires I. El síndrome de Ekiri como una complicación de la shigellosis. Enferm Infecc Microbiol Clin 2007; 25:492-3. [PMID: 17692219 DOI: 10.1157/13108716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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