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Krasemann S, Haferkamp U, Pfefferle S, Woo MS, Heinrich F, Schweizer M, Appelt-Menzel A, Cubukova A, Barenberg J, Leu J, Hartmann K, Thies E, Littau JL, Sepulveda-Falla D, Zhang L, Ton K, Liang Y, Matschke J, Ricklefs F, Sauvigny T, Sperhake J, Fitzek A, Gerhartl A, Brachner A, Geiger N, König EM, Bodem J, Franzenburg S, Franke A, Moese S, Müller FJ, Geisslinger G, Claussen C, Kannt A, Zaliani A, Gribbon P, Ondruschka B, Neuhaus W, Friese MA, Glatzel M, Pless O. The blood-brain barrier is dysregulated in COVID-19 and serves as a CNS entry route for SARS-CoV-2. Stem Cell Reports 2022; 17:307-320. [PMID: 35063125 PMCID: PMC8772030 DOI: 10.1016/j.stemcr.2021.12.011] [Citation(s) in RCA: 113] [Impact Index Per Article: 56.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 12/15/2021] [Accepted: 12/16/2021] [Indexed: 12/11/2022] Open
Abstract
Neurological complications are common in COVID-19. Although SARS-CoV-2 has been detected in patients’ brain tissues, its entry routes and resulting consequences are not well understood. Here, we show a pronounced upregulation of interferon signaling pathways of the neurovascular unit in fatal COVID-19. By investigating the susceptibility of human induced pluripotent stem cell (hiPSC)-derived brain capillary endothelial-like cells (BCECs) to SARS-CoV-2 infection, we found that BCECs were infected and recapitulated transcriptional changes detected in vivo. While BCECs were not compromised in their paracellular tightness, we found SARS-CoV-2 in the basolateral compartment in transwell assays after apical infection, suggesting active replication and transcellular transport of virus across the blood-brain barrier (BBB) in vitro. Moreover, entry of SARS-CoV-2 into BCECs could be reduced by anti-spike-, anti-angiotensin-converting enzyme 2 (ACE2)-, and anti-neuropilin-1 (NRP1)-specific antibodies or the transmembrane protease serine subtype 2 (TMPRSS2) inhibitor nafamostat. Together, our data provide strong support for SARS-CoV-2 brain entry across the BBB resulting in increased interferon signaling. IFNγ signaling is upregulated in COVID-19 human neurovascular unit SARS-CoV-2-infected hiPS-BCECs display similar upregulation of IFNγ signaling SARS-CoV-2 replicates in hiPS-BCECs and is released while barrier remains intact SARS-CoV-2 infection of hiPS-BCECs is decreased by antibodies and protease inhibitors
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2
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Nicholas B, Staples KJ, Moese S, Meldrum E, Ward J, Dennison P, Havelock T, Hinks TSC, Amer K, Woo E, Chamberlain M, Singh N, North M, Pink S, Wilkinson TMA, Djukanović R. A novel lung explant model for the ex vivo study of efficacy and mechanisms of anti-influenza drugs. J Immunol 2015; 194:6144-54. [PMID: 25934861 PMCID: PMC4456633 DOI: 10.4049/jimmunol.1402283] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 04/06/2015] [Indexed: 11/19/2022]
Abstract
Influenza A virus causes considerable morbidity and mortality largely because of a lack of effective antiviral drugs. Viral neuraminidase inhibitors, which inhibit viral release from the infected cell, are currently the only approved drugs for influenza, but have recently been shown to be less effective than previously thought. Growing resistance to therapies that target viral proteins has led to increased urgency in the search for novel anti-influenza compounds. However, discovery and development of new drugs have been restricted because of differences in susceptibility to influenza between animal models and humans and a lack of translation between cell culture and in vivo measures of efficacy. To circumvent these limitations, we developed an experimental approach based on ex vivo infection of human bronchial tissue explants and optimized a method of flow cytometric analysis to directly quantify infection rates in bronchial epithelial tissues. This allowed testing of the effectiveness of TVB024, a vATPase inhibitor that inhibits viral replication rather than virus release, and to compare efficacy with the current frontline neuraminidase inhibitor, oseltamivir. The study showed that the vATPase inhibitor completely abrogated epithelial cell infection, virus shedding, and the associated induction of proinflammatory mediators, whereas oseltamivir was only partially effective at reducing these mediators and ineffective against innate responses. We propose, therefore, that this explant model could be used to predict the efficacy of novel anti-influenza compounds targeting diverse stages of the viral replication cycle, thereby complementing animal models and facilitating progression of new drugs into clinical trials.
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Affiliation(s)
- Ben Nicholas
- Clinical and Experimental Sciences, University of Southampton Faculty of Medicine, Sir Henry Wellcome Laboratories, Southampton General Hospital, Southampton SO16 6YD, United Kingdom; Southampton National Institute for Health Research Respiratory Biomedical Research Unit, Southampton General Hospital, Southampton SO16 6YD, United Kingdom;
| | - Karl J Staples
- Clinical and Experimental Sciences, University of Southampton Faculty of Medicine, Sir Henry Wellcome Laboratories, Southampton General Hospital, Southampton SO16 6YD, United Kingdom; Southampton National Institute for Health Research Respiratory Biomedical Research Unit, Southampton General Hospital, Southampton SO16 6YD, United Kingdom
| | | | | | - Jon Ward
- Clinical and Experimental Sciences, University of Southampton Faculty of Medicine, Sir Henry Wellcome Laboratories, Southampton General Hospital, Southampton SO16 6YD, United Kingdom
| | - Patrick Dennison
- Clinical and Experimental Sciences, University of Southampton Faculty of Medicine, Sir Henry Wellcome Laboratories, Southampton General Hospital, Southampton SO16 6YD, United Kingdom; Southampton National Institute for Health Research Respiratory Biomedical Research Unit, Southampton General Hospital, Southampton SO16 6YD, United Kingdom
| | - Tom Havelock
- Clinical and Experimental Sciences, University of Southampton Faculty of Medicine, Sir Henry Wellcome Laboratories, Southampton General Hospital, Southampton SO16 6YD, United Kingdom; Southampton National Institute for Health Research Respiratory Biomedical Research Unit, Southampton General Hospital, Southampton SO16 6YD, United Kingdom
| | - Timothy S C Hinks
- Clinical and Experimental Sciences, University of Southampton Faculty of Medicine, Sir Henry Wellcome Laboratories, Southampton General Hospital, Southampton SO16 6YD, United Kingdom; Southampton National Institute for Health Research Respiratory Biomedical Research Unit, Southampton General Hospital, Southampton SO16 6YD, United Kingdom
| | - Khalid Amer
- Department of Cardiothoracic Surgery, Southampton General Hospital, Southampton SO16 6YD, United Kingdom; and
| | - Edwin Woo
- Department of Cardiothoracic Surgery, Southampton General Hospital, Southampton SO16 6YD, United Kingdom; and
| | - Martin Chamberlain
- Department of Cardiothoracic Surgery, Southampton General Hospital, Southampton SO16 6YD, United Kingdom; and
| | - Neeta Singh
- Department of Cellular Pathology, Southampton General Hospital, Southampton SO16 6YD, United Kingdom
| | - Malcolm North
- Southampton National Institute for Health Research Respiratory Biomedical Research Unit, Southampton General Hospital, Southampton SO16 6YD, United Kingdom
| | - Sandy Pink
- Southampton National Institute for Health Research Respiratory Biomedical Research Unit, Southampton General Hospital, Southampton SO16 6YD, United Kingdom
| | - Tom M A Wilkinson
- Clinical and Experimental Sciences, University of Southampton Faculty of Medicine, Sir Henry Wellcome Laboratories, Southampton General Hospital, Southampton SO16 6YD, United Kingdom; Southampton National Institute for Health Research Respiratory Biomedical Research Unit, Southampton General Hospital, Southampton SO16 6YD, United Kingdom
| | - Ratko Djukanović
- Clinical and Experimental Sciences, University of Southampton Faculty of Medicine, Sir Henry Wellcome Laboratories, Southampton General Hospital, Southampton SO16 6YD, United Kingdom; Southampton National Institute for Health Research Respiratory Biomedical Research Unit, Southampton General Hospital, Southampton SO16 6YD, United Kingdom
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Jurgeit A, McDowell R, Moese S, Meldrum E, Schwendener R, Greber UF. Niclosamide is a proton carrier and targets acidic endosomes with broad antiviral effects. PLoS Pathog 2012; 8:e1002976. [PMID: 23133371 PMCID: PMC3486884 DOI: 10.1371/journal.ppat.1002976] [Citation(s) in RCA: 166] [Impact Index Per Article: 13.8] [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: 06/30/2012] [Accepted: 09/04/2012] [Indexed: 12/15/2022] Open
Abstract
Viruses use a limited set of host pathways for infection. These pathways represent bona fide antiviral targets with low likelihood of viral resistance. We identified the salicylanilide niclosamide as a broad range antiviral agent targeting acidified endosomes. Niclosamide is approved for human use against helminthic infections, and has anti-neoplastic and antiviral effects. Its mode of action is unknown. Here, we show that niclosamide, which is a weak lipophilic acid inhibited infection with pH-dependent human rhinoviruses (HRV) and influenza virus. Structure-activity studies showed that antiviral efficacy and endolysosomal pH neutralization co-tracked, and acidification of the extracellular medium bypassed the virus entry block. Niclosamide did not affect the vacuolar H(+)-ATPase, but neutralized coated vesicles or synthetic liposomes, indicating a proton carrier mode-of-action independent of any protein target. This report demonstrates that physico-chemical interference with host pathways has broad range antiviral effects, and provides a proof of concept for the development of host-directed antivirals.
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Affiliation(s)
- Andreas Jurgeit
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Robert McDowell
- 3-V Biosciences Inc., Menlo Park, California, United States of America
| | - Stefan Moese
- 3-V Biosciences Inc., Menlo Park, California, United States of America
| | - Eric Meldrum
- 3-V Biosciences Inc., Menlo Park, California, United States of America
| | - Reto Schwendener
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Urs F. Greber
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
- * E-mail:
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Snijder B, Sacher R, Rämö P, Liberali P, Mench K, Wolfrum N, Burleigh L, Scott CC, Verheije MH, Mercer J, Moese S, Heger T, Theusner K, Jurgeit A, Lamparter D, Balistreri G, Schelhaas M, De Haan CAM, Marjomäki V, Hyypiä T, Rottier PJM, Sodeik B, Marsh M, Gruenberg J, Amara A, Greber U, Helenius A, Pelkmans L. Single-cell analysis of population context advances RNAi screening at multiple levels. Mol Syst Biol 2012; 8:579. [PMID: 22531119 PMCID: PMC3361004 DOI: 10.1038/msb.2012.9] [Citation(s) in RCA: 140] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
A large set of high-content RNAi screens investigating mammalian virus infection and multiple cellular activities is analysed to reveal the impact of population context on phenotypic variability and to identify indirect RNAi effects. ![]()
Cell population context determines phenotypes in RNAi screens of multiple cellular activities (including virus infection, cell size regulation, endocytosis, and lipid homeostasis), which can be accounted for by a combination of novel image analysis and multivariate statistical methods. Accounting for cell population context-mediated effects strongly changes the reproducibility and consistency of RNAi screens across cell lines as well as of siRNAs targeting the same gene. Such analyses can identify the perturbed regulation of population context dependent cell-to-cell variability, a novel perturbation phenotype. Overall, these methods advance the use of large-scale RNAi screening for a systems-level understanding of cellular processes.
Isogenic cells in culture show strong variability, which arises from dynamic adaptations to the microenvironment of individual cells. Here we study the influence of the cell population context, which determines a single cell's microenvironment, in image-based RNAi screens. We developed a comprehensive computational approach that employs Bayesian and multivariate methods at the single-cell level. We applied these methods to 45 RNA interference screens of various sizes, including 7 druggable genome and 2 genome-wide screens, analysing 17 different mammalian virus infections and four related cell physiological processes. Analysing cell-based screens at this depth reveals widespread RNAi-induced changes in the population context of individual cells leading to indirect RNAi effects, as well as perturbations of cell-to-cell variability regulators. We find that accounting for indirect effects improves the consistency between siRNAs targeted against the same gene, and between replicate RNAi screens performed in different cell lines, in different labs, and with different siRNA libraries. In an era where large-scale RNAi screens are increasingly performed to reach a systems-level understanding of cellular processes, we show that this is often improved by analyses that account for and incorporate the single-cell microenvironment.
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Affiliation(s)
- Berend Snijder
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
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Jurgeit A, Moese S, Roulin P, Dorsch A, Lötzerich M, Lee WM, Greber UF. An RNA replication-center assay for high content image-based quantifications of human rhinovirus and coxsackievirus infections. Virol J 2010; 7:264. [PMID: 20937137 PMCID: PMC2958916 DOI: 10.1186/1743-422x-7-264] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Accepted: 10/11/2010] [Indexed: 01/17/2023] Open
Abstract
Background Picornaviruses are common human and animal pathogens, including polio and rhinoviruses of the enterovirus family, and hepatits A or food-and-mouth disease viruses. There are no effective countermeasures against the vast majority of picornaviruses, with the exception of polio and hepatitis A vaccines. Human rhinoviruses (HRV) are the most prevalent picornaviruses comprising more than one hundred serotypes. The existing and also emerging HRVs pose severe health risks for patients with asthma or chronic obstructive pulmonary disease. Here, we developed a serotype-independent infection assay using a commercially available mouse monoclonal antibody (mabJ2) detecting double-strand RNA. Results Immunocytochemical staining for RNA replication centers using mabJ2 identified cells that were infected with either HRV1A, 2, 14, 16, 37 or coxsackievirus (CV) B3, B4 or A21. MabJ2 labeled-cells were immunocytochemically positive for newly synthesized viral capsid proteins from HRV1A, 14, 16, 37 or CVB3, 4. We optimized the procedure for detection of virus replication in settings for high content screening with automated fluorescence microscopy and single cell analysis. Our data show that the infection signal was dependent on multiplicity, time and temperature of infection, and the mabJ2-positive cell numbers correlated with viral titres determined in single step growth curves. The mabJ2 infection assay was adapted to determine the efficacy of anti-viral compounds and small interfering RNAs (siRNAs) blocking enterovirus infections. Conclusions We report a broadly applicable, rapid protocol to measure infection of cultured cells with enteroviruses at single cell resolution. This assay can be applied to a wide range of plus-sense RNA viruses, and hence allows comparative studies of viral infection biology without dedicated reagents or procedures. This protocol also allows to directly compare results from small compound or siRNA infection screens for different serotypes without the risk of assay specific artifacts.
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Affiliation(s)
- Andreas Jurgeit
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
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Moese S, Selbach M, Brinkmann V, Karlas A, Haimovich B, Backert S, Meyer TF. The Helicobacter pylori CagA protein disrupts matrix adhesion of gastric epithelial cells by dephosphorylation of vinculin. Cell Microbiol 2007; 9:1148-61. [PMID: 17217431 DOI: 10.1111/j.1462-5822.2006.00856.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Helicobacter pylori colonizes the human stomach, contributing to or causing several diseases. Translocation of the CagA bacterial protein into gastric epithelial cells has been linked to an increased risk of peptic ulcer disease and gastric carcinoma. Upon translocation, CagA is tyrosine phosphorylated by Src family kinases (SFKs), which themselves become inactivated via a negative feedback loop. Here, we show that tyrosine-phosphorylated CagA disrupts adhesion of AGS cells to the extracellular matrix. Owing to the inactivation of c-Src via CagA interaction, vinculin is dephosphorylated at tyrosine residues, 100 and 1065, by corresponding phosphatases. Vinculin dephosphorylation disturbs the interaction and recruitment of the actin-related protein 2/3 (Arp2/3) complex by p34Arc, resulting in a reduction of focal adhesion complexes. These defects can be mimicked by downregulating vinculin using RNA interference in non-infected cells. Tyrosine dephosphorylation of vinculin results in severe cellular deficiencies in cell-matrix adhesion, cell spreading and wound repair. We hypothesize that CagA-mediated inactivation of vinculin is a key step in the mechanism by which H. pylori induces damage to the gastric epithelium and represents an important step in disease development.
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Affiliation(s)
- Stefan Moese
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Charitéplatz 1, 10117 Berlin, Germany
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7
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Bauer B, Moese S, Bartfeld S, Meyer TF, Selbach M. Analysis of cell type-specific responses mediated by the type IV secretion system of Helicobacter pylori. Infect Immun 2005; 73:4643-52. [PMID: 16040977 PMCID: PMC1201271 DOI: 10.1128/iai.73.8.4643-4652.2005] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Helicobacter pylori persistently infects the human stomach and can cause gastritis, gastric ulceration, and gastric cancer. The type IV secretion system (TFSS) of virulent H. pylori strains translocates the CagA protein, inducing the dephosphorylation of host cell proteins and leading to changes in the morphology or shape of AGS gastric epithelial cells. Furthermore, the TFSS is involved in the induction of proinflammatory cytokines. While the H. pylori genes required for TFSS function have been investigated systematically, little is known about possible host cell factors involved. We infected 19 different mammalian cell lines individually with H. pylori and analyzed CagA translocation, dephosphorylation of host cell proteins, chemokine secretion (interleukin-8 and macrophage inflammatory protein 2), and changes in cellular phenotypes. Our results demonstrate that not only bacterial but also host cell factors determine the cellular response to infection. The identification of such unknown host cell factors will add to our understanding of host-pathogen interactions and might help in the development of new therapeutic strategies.
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Affiliation(s)
- Bianca Bauer
- Max-Planck-Institut für Infektionsbiologie, Abt. Molekulare Biologie, Schumannstr. 20/21, D-10117 Berlin, Germany
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Abstract
Helicobacter pylori is one of the most wide-spread bacterial pathogens and infects the human stomach to cause diseases, such as gastritis, gastric ulceration, and gastric cancer. A major virulence determinant is the H. pylori CagA protein (encoded by the cytotoxin-associated gene A) which is translocated from the bacteria into the cytoplasm of host cells by a type IV secretion system. In the host cell, CagA is phosphorylated on tyrosine residues and induces rearrangements of the actin cytoskeleton. We have previously shown that tyrosine-phosphorylated CagA inhibits the catalytic activity of Src family kinases and induces tyrosine dephosphorylation of several host cell proteins. Here, we identified one of these proteins as ezrin by a combination of preparative gel electrophoresis, two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS). Specific pharmacological inhibition of Src family kinases also induces ezrin dephosphorylation. Therefore, ezrin dephosphorylation appears to be induced by CagA-mediated Src inactivation. Ezrin is the founding member of the ezrin-radixin-moesin (ERM) family of proteins which are signalling integrators at the cell cortex. Since ezrin is a component of microvilli and a linker protein between actin filaments and membrane proteins, this observation has important implications for H. pylori pathogenesis and might also help to explain the development of gastric cancer.
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Affiliation(s)
- Matthias Selbach
- Max-Planck-Institut für Infektionsbiologie, Abt. Molekulare Biologie, Berlin, Germany
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9
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Moese S, Selbach M, Kwok T, Brinkmann V, König W, Meyer TF, Backert S. Helicobacter pylori induces AGS cell motility and elongation via independent signaling pathways. Infect Immun 2004; 72:3646-9. [PMID: 15155677 PMCID: PMC415712 DOI: 10.1128/iai.72.6.3646-3649.2004] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Helicobacter pylori induces motogenic and cytoskeletal responses in gastric epithelial cells. We demonstrate that these responses can be induced via independent signaling pathways that often occur in parallel. The cag pathogenicity island appears to be nonessential for induction of motility, whereas the elongation phenotype depends on translocation and phosphorylation of CagA.
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Affiliation(s)
- Stefan Moese
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
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10
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Selbach M, Moese S, Hurwitz R, Hauck CR, Meyer TF, Backert S. The Helicobacter pylori CagA protein induces cortactin dephosphorylation and actin rearrangement by c-Src inactivation. EMBO J 2003; 22:515-28. [PMID: 12554652 PMCID: PMC140734 DOI: 10.1093/emboj/cdg050] [Citation(s) in RCA: 187] [Impact Index Per Article: 8.9] [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] [Indexed: 12/14/2022] Open
Abstract
The gastric pathogen Helicobacter pylori translocates the CagA protein into epithelial cells by a type IV secretion process. Translocated CagA is tyrosine phosphorylated (CagA(P-Tyr)) on specific EPIYA sequence repeats by Src family tyrosine kinases. Phos phorylation of CagA induces the dephosphorylation of as yet unidentified cellular proteins, rearrangements of the host cell actin cytoskeleton and cell scattering. We show here that CagA(P-Tyr) inhibits the catalytic activity of c-Src in vivo and in vitro. c-Src inactivation leads to tyrosine dephosphorylation of the actin binding protein cortactin. Concomitantly, cortactin is specifically redistributed to actin-rich cellular protrusions. c-Src inactivation and cortactin dephosphorylation are required for rearrangements of the actin cytoskeleton. Moreover, CagA(P-Tyr)-mediated c-Src inhibition downregulates further CagA phosphorylation through a negative feedback loop. This is the first report of a bacterial virulence factor that inhibits signalling of a eukaryotic tyrosine kinase and on a role of c-Src inactivation in host cell cytoskeletal rearrangements.
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Affiliation(s)
| | | | | | - Christof R. Hauck
- Max-Planck-Institut für Infektionsbiologie, Abt. Molekulare Biologie, Schumannstrasse 20/21, D-10117 Berlin and
Zentrum für Infektionsforschung, Universität Würzburg, Röntgenring 11, D-97070 Würzburg, Germany Corresponding author e-mail:
| | - Thomas F. Meyer
- Max-Planck-Institut für Infektionsbiologie, Abt. Molekulare Biologie, Schumannstrasse 20/21, D-10117 Berlin and
Zentrum für Infektionsforschung, Universität Würzburg, Röntgenring 11, D-97070 Würzburg, Germany Corresponding author e-mail:
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Moese S, Selbach M, Meyer TF, Backert S. cag+ Helicobacter pylori induces homotypic aggregation of macrophage-like cells by up-regulation and recruitment of intracellular adhesion molecule 1 to the cell surface. Infect Immun 2002; 70:4687-91. [PMID: 12117984 PMCID: PMC128178 DOI: 10.1128/iai.70.8.4687-4691.2002] [Citation(s) in RCA: 25] [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] [Indexed: 01/29/2023] Open
Abstract
Infection with cag+ but not cag-negative Helicobacter pylori leads to the formation of large homotypic aggregates of macrophage-like cells. Intracellular adhesion molecule 1 is up-regulated and recruited to the cell surface of infected cells and mediates the aggregation via lymphocyte function-associated molecule 1. This signaling may regulate cell-cell interactions and inflammatory responses.
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Affiliation(s)
- Stefan Moese
- Abteilung Molekulare Biologie, Max-Planck-Institut für Infektionsbiologie, D-10117 Berlin, Germany
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12
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Abstract
The gastric pathogen Helicobacter pylori uses a type IV secretion system to inject the bacterial CagA protein into gastric epithelial cells. Within the host cell, CagA becomes phosphorylated on tyrosine residues and initiates cytoskeletal rearrangements. We demonstrate here that Src-like protein-tyrosine kinases mediate CagA phosphorylation in vitro and in vivo. First, the Src-specific tyrosine kinase inhibitor PP2 specifically blocks CagA phosphorylation and cytoskeletal rearrangements thereby inhibiting the CagA-induced hummingbird phenotype of gastric epithelial cells. Second, CagA is in vivo phosphorylated by transiently expressed c-Src. Third, recombinant c-Src and lysates derived from c-Src-expressing fibroblasts but not lysates derived from Src-, Yes-, and Fyn-deficient cells phosphorylated CagA in vitro. Fourth, a transfected CagA-GFP fusion protein is phosphorylated in vivo in Src-positive fibroblasts but not in Src-, Yes-, and Fyn-deficient cells. Because a CagA-GFP fusion protein mutated in an EPIYA motif is not efficiently phosphorylated in any of these fibroblast cells, the CagA EPIYA motif appears to constitute the major c-Src phosphorylation site conserved among CagA-positive Helicobacter strains.
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Affiliation(s)
- Matthias Selbach
- Max-Planck-Institut für Infektionsbiologie, Abt. Molekulare Biologie, Schumannstrasse 20/21, D-10117 Berlin, Germany
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13
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Selbach M, Moese S, Meyer TF, Backert S. Functional analysis of the Helicobacter pylori cag pathogenicity island reveals both VirD4-CagA-dependent and VirD4-CagA-independent mechanisms. Infect Immun 2002; 70:665-71. [PMID: 11796597 PMCID: PMC127714 DOI: 10.1128/iai.70.2.665-671.2002] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The type IV secretion machinery encoded by the cag pathogenicity island (PAI) of Helicobacter pylori has been implicated in a series of host responses during infection. Here, we analyzed the function of 12 cag PAI genes from both cag I and cag II loci, including the complete virB/D complex (virB4, virB7, virB8, virB9, virB10, virB11, and virD4). We monitored interleukin-8 (IL-8) secretion, CagA translocation and tyrosine phosphorylation, and induction of a scattering ("hummingbird") phenotype upon H. pylori infection of AGS gastric epithelial cells. For the first time, we have complemented individual cag PAI gene knockout mutants with their intact genes expressed from a shuttle vector and showed that complemented CagA and VirD4 restored wild-type function. Our results demonstrate that phenotypic changes and phosphorylation of CagA depended on all virB/D genes and several other genes of the cag PAI. Induction of IL-8 secretion depended largely on the same set of genes but was independent of CagA and VirD4. Thus, CagA translocation and induction of IL-8 secretion are regulated by VirD4-CagA-dependent and VirD4-CagA-independent mechanisms, respectively. The function of VirD4 as a possible adapter protein which guides CagA into the type IV secretion channel is presented in a model.
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Affiliation(s)
- Matthias Selbach
- Abteilung Molekulare Biologie, Max-Planck-Institut für Infektionsbiologie, D-10117 Berlin, Germany
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14
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Moese S, Selbach M, Zimny-Arndt U, Jungblut PR, Meyer TF, Backert S. Identification of a tyrosine-phosphorylated 35 kDa carboxy-terminal fragment (p35CagA) of the Helicobacter pylori CagA protein in phagocytic cells: processing or breakage? Proteomics 2001. [PMID: 11681214 DOI: 10.1002/1615-9861(200104)1:4<618::aid-prot618>3.0.co;2-c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Helicobacter pylori is a very common bacterial pathogen that causes gastric disease by inducing the infiltration of immune cells as an initial event. Virulent H. pylori strains express a type IV secretion system composed of several virulence (Vir) proteins encoded by the cag pathogenicity island (cag PAI). During infection of phagocytic cells (U937, Josk-M and J774A.1) we have detected a de novo tyrosine-phosphorylated protein (p35p-Tyr) with sizes of 30 kDa, 38 kDa or 40 kDa, depending on the H. pylori strain. p35p-Tyr occurrence required functional virB4, virB7, virB10, virB11, virD4 and cagA (cytotoxin-associated gene A) genes encoded by the cag PAI suggesting that p35p-Tyr is a bacterial protein of variable size. We have biochemically purified p35p-Tyr from infected U937 cells. Tryptic peptides of p35p-Tyr determined by matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) identified the carboxy (C)-terminal part of the H. pylori CagA protein. Subsequent analysis by two-dimensional electrophoresis (2-DE) and immunoblotting using anti-CagA antibodies revealed the presence of three stable CagA protein species in phagocytes: (i) 130-140 kDa full-length CagA (p135CagA), (ii) a 100-105 kDa fragment (p100CagA) and (iii) a 30-40 kDa fragment (p35CagA). Unlike p135CagA, p35CagA and p100CagA were also detected in much lower amounts in H. pylori without host cell contact. Therefore, breakage or processing leads to the production of p35CagA and p100CagA, a process that is enhanced after translocation into host cells. MALDI-MS data and the isoelectric point determined by both 2-DE and sequence analysis suggested that p35CagA represents the C-terminal part of CagA and p100CagA corresponds to the remaining amino (N)-terminal fragment. The possible function of CagA in host signal transduction and development of gastric disease is discussed.
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Affiliation(s)
- S Moese
- Max-Planck-Institut für Infektionsbiologie, Abt., Molekulare Biologie, Schumannstr. 20/21, D-10117 Berlin, Germany
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Backert S, Moese S, Selbach M, Brinkmann V, Meyer TF. Phosphorylation of tyrosine 972 of the Helicobacter pylori CagA protein is essential for induction of a scattering phenotype in gastric epithelial cells. Mol Microbiol 2001; 42:631-44. [PMID: 11722731 DOI: 10.1046/j.1365-2958.2001.02649.x] [Citation(s) in RCA: 187] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Helicobacter pylori colonizes the human stomach and is the causative agent of a variety of gastric diseases. After bacterial attachment, the H. pylori CagA protein is translocated into gastric epithelial cells and tyrosine phosphorylated. This process is associated with characteristic cytoskeletal rearrangements, resulting in a scatter factor-like ('hummingbird') phenotype. In this study, using a cagA mutant complemented with wild-type cagA and transiently expressing CagA in AGS cells, we have demonstrated that translocated CagA is necessary for rearrangements of the actin cytoskeleton to occur. Anti-phosphotyrosine immunoblotting studies and treatment of infected cells with phosphotyrosine kinase inhibitors suggested that not only translocation but also phosphorylation of CagA is important in this process. Transient expression of CagA-green fluorescent protein (GFP) fusion proteins and two-dimensional gel electrophoresis of CagA protein species demonstrated tyrosine phosphorylation in the C-terminus. Site-directed mutagenesis of CagA revealed that tyrosine residue 972 is essential for induction of the cellular phenotype. We have also demonstrated that translocation and phosphorylation of CagA is necessary but not sufficient for induction of the hummingbird phenotype in AGS cells, indicating the involvement of as yet unidentified bacterial factor(s).
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Affiliation(s)
- S Backert
- Max-Planck-Institut für Infektionsbiologie, Abt. Molekulare Biologie, Schumannstr. 20/21, D-10117 Berlin, Germany
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Moese S, Selbach M, Zimny-Arndt U, Jungblut PR, Meyer TF, Backert S. Identification of a tyrosine-phosphorylated 35 kDa carboxy-terminal fragment (p35CagA) of the Helicobacter pylori CagA protein in phagocytic cells: processing or breakage? Proteomics 2001; 1:618-29. [PMID: 11681214 DOI: 10.1002/1615-9861(200104)1:4<618::aid-prot618>3.0.co;2-c] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Helicobacter pylori is a very common bacterial pathogen that causes gastric disease by inducing the infiltration of immune cells as an initial event. Virulent H. pylori strains express a type IV secretion system composed of several virulence (Vir) proteins encoded by the cag pathogenicity island (cag PAI). During infection of phagocytic cells (U937, Josk-M and J774A.1) we have detected a de novo tyrosine-phosphorylated protein (p35p-Tyr) with sizes of 30 kDa, 38 kDa or 40 kDa, depending on the H. pylori strain. p35p-Tyr occurrence required functional virB4, virB7, virB10, virB11, virD4 and cagA (cytotoxin-associated gene A) genes encoded by the cag PAI suggesting that p35p-Tyr is a bacterial protein of variable size. We have biochemically purified p35p-Tyr from infected U937 cells. Tryptic peptides of p35p-Tyr determined by matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) identified the carboxy (C)-terminal part of the H. pylori CagA protein. Subsequent analysis by two-dimensional electrophoresis (2-DE) and immunoblotting using anti-CagA antibodies revealed the presence of three stable CagA protein species in phagocytes: (i) 130-140 kDa full-length CagA (p135CagA), (ii) a 100-105 kDa fragment (p100CagA) and (iii) a 30-40 kDa fragment (p35CagA). Unlike p135CagA, p35CagA and p100CagA were also detected in much lower amounts in H. pylori without host cell contact. Therefore, breakage or processing leads to the production of p35CagA and p100CagA, a process that is enhanced after translocation into host cells. MALDI-MS data and the isoelectric point determined by both 2-DE and sequence analysis suggested that p35CagA represents the C-terminal part of CagA and p100CagA corresponds to the remaining amino (N)-terminal fragment. The possible function of CagA in host signal transduction and development of gastric disease is discussed.
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Affiliation(s)
- S Moese
- Max-Planck-Institut für Infektionsbiologie, Abt., Molekulare Biologie, Schumannstr. 20/21, D-10117 Berlin, Germany
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