1
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Aziz UBA, Saoud A, Bermudez M, Mieth M, Atef A, Rudolf T, Arkona C, Trenkner T, Böttcher C, Ludwig K, Hoelzemer A, Hocke AC, Wolber G, Rademann J. Targeted small molecule inhibitors blocking the cytolytic effects of pneumolysin and homologous toxins. Nat Commun 2024; 15:3537. [PMID: 38670939 PMCID: PMC11053136 DOI: 10.1038/s41467-024-47741-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 04/08/2024] [Indexed: 04/28/2024] Open
Abstract
Pneumolysin (PLY) is a cholesterol-dependent cytolysin (CDC) from Streptococcus pneumoniae, the main cause for bacterial pneumonia. Liberation of PLY during infection leads to compromised immune system and cytolytic cell death. Here, we report discovery, development, and validation of targeted small molecule inhibitors of PLY (pore-blockers, PB). PB-1 is a virtual screening hit inhibiting PLY-mediated hemolysis. Structural optimization provides PB-2 with improved efficacy. Cryo-electron tomography reveals that PB-2 blocks PLY-binding to cholesterol-containing membranes and subsequent pore formation. Scaffold-hopping delivers PB-3 with superior chemical stability and solubility. PB-3, formed in a protein-templated reaction, binds to Cys428 adjacent to the cholesterol recognition domain of PLY with a KD of 256 nM and a residence time of 2000 s. It acts as anti-virulence factor preventing human lung epithelial cells from PLY-mediated cytolysis and cell death during infection with Streptococcus pneumoniae and is active against the homologous Cys-containing CDC perfringolysin (PFO) as well.
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Affiliation(s)
- Umer Bin Abdul Aziz
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Str. 2+4, 14195, Berlin, Germany
| | - Ali Saoud
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Str. 2+4, 14195, Berlin, Germany
| | - Marcel Bermudez
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Str. 2+4, 14195, Berlin, Germany
- Institute for Pharmaceutical and Medicinal Chemistry, University of Münster, Corrensstr. 48, 48149, Münster, Germany
| | - Maren Mieth
- Department of Infectious Diseases, Respiratory Medicine, and Critical Care, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Amira Atef
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Str. 2+4, 14195, Berlin, Germany
- Department of Medicinal Chemistry, Faculty of Pharmacy, Assuit University, Assiut, 71526, Egypt
| | - Thomas Rudolf
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Str. 2+4, 14195, Berlin, Germany
| | - Christoph Arkona
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Str. 2+4, 14195, Berlin, Germany
| | - Timo Trenkner
- Leibniz Institute of Virology, Hamburg, 20251, Germany
| | - Christoph Böttcher
- Institute of Chemistry and Biochemistry, Research Center of Electron Microscopy (FZEM), Freie Universität Berlin, Fabeckstraße 36A, 14195, Berlin, Germany
| | - Kai Ludwig
- Institute of Chemistry and Biochemistry, Research Center of Electron Microscopy (FZEM), Freie Universität Berlin, Fabeckstraße 36A, 14195, Berlin, Germany
| | - Angelique Hoelzemer
- Leibniz Institute of Virology, Hamburg, 20251, Germany
- First Department of Medicine, University Medical Center Hamburg-Eppendorf (UKE), 20251, Hamburg, Germany
| | - Andreas C Hocke
- Department of Infectious Diseases, Respiratory Medicine, and Critical Care, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Gerhard Wolber
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Str. 2+4, 14195, Berlin, Germany
| | - Jörg Rademann
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Str. 2+4, 14195, Berlin, Germany.
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2
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Hathaway A, Qian G, King J, McGuinness S, Maskell N, Oliver J, Finn A, Danon L, Challen R, Toye AM, Hyams C. Association of ABO and Rhesus blood groups with severe outcomes from non-SARS-CoV-2 respiratory infection: A prospective observational cohort study in Bristol, UK 2020-2022. Br J Haematol 2024; 204:826-838. [PMID: 38009561 PMCID: PMC7616671 DOI: 10.1111/bjh.19234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 11/15/2023] [Accepted: 11/16/2023] [Indexed: 11/29/2023]
Abstract
Despite significant global morbidity associated with respiratory infection, there is a paucity of data examining the association between severity of non-SARS-CoV-2 respiratory infection and blood group. We analysed a prospective cohort of adults hospitalised in Bristol, UK, from 1 August 2020 to 31 July 2022, including patients with acute respiratory infection (pneumonia [n = 1934] and non-pneumonic lower respiratory tract infection [NP-LRTI] [n = 1184]), a negative SARS-CoV-2 test and known blood group status. The likelihood of cardiovascular complication, survival and hospital admission length was assessed using regression models with group O and RhD-negative status as reference groups. Group A and RhD-positive were over-represented in both pneumonia and NP-LRTI compared to a first-time donor population (p < 0.05 in all); contrastingly, group O was under-represented. ABO group did not influence cardiovascular complication risk; however, RhD-positive patients with pneumonia had a reduced odds ratio (OR) for cardiovascular complications (OR = 0.77 [95% CI = 0.59-0.98]). Compared to group O, group A individuals with NP-LRTI were more likely to be discharged within 60 days (hazard ratio [HR] = 1.17 [95% CI = 1.03-1.33]), while group B with pneumonia was less likely (HR = 0.8 [95% CI = 0.66-0.96]). This analysis provides some evidence that blood group status may influence clinical outcome following respiratory infection, with group A having increased risk of hospitalisation and RhD-positive patients having reduced cardiovascular complications.
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Affiliation(s)
- Alice Hathaway
- School of Biochemistry, University of Bristol, Bristol, UK
| | - George Qian
- Engineering Mathematics, University of Bristol, Bristol, UK
| | - Jade King
- Clinical Research and Imaging Centre, UHBW NHS Trust, Bristol, UK
| | - Serena McGuinness
- Bristol Vaccine Centre and Population Health Sciences, University of Bristol, Bristol, UK
| | - Nick Maskell
- Academic Respiratory Unit, University of Bristol, Southmead Hospital, Bristol, UK
| | - Jennifer Oliver
- Bristol Vaccine Centre and Population Health Sciences, University of Bristol, Bristol, UK
| | - Adam Finn
- Bristol Vaccine Centre, Cellular and Molecular Medicine and Population Health Sciences, University of Bristol, Bristol, UK
| | - Leon Danon
- Engineering Mathematics, University of Bristol, Bristol, UK
| | - Robert Challen
- Engineering Mathematics, University of Bristol, Bristol, UK
| | - Ashley M Toye
- School of Biochemistry, University of Bristol, Bristol, UK
| | - Catherine Hyams
- Bristol Vaccine Centre, Cellular and Molecular Medicine and Population Health Sciences, University of Bristol, Bristol, UK
- Academic Respiratory Unit and Bristol Vaccine Centre, University of Bristol, Bristol, UK
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3
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Alfano DN, Miller MJ, Bubeck Wardenburg J. Endothelial ADAM10 utilization defines a molecular pathway of vascular injury in mice with bacterial sepsis. J Clin Invest 2023; 133:e168450. [PMID: 37788087 PMCID: PMC10688991 DOI: 10.1172/jci168450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 09/28/2023] [Indexed: 10/05/2023] Open
Abstract
The endothelium plays a critical role in the host response to infection and has been a focus of investigation in sepsis. While it is appreciated that intravascular thrombus formation, severe inflammation, and loss of endothelial integrity impair tissue oxygenation during sepsis, the precise molecular mechanisms that lead to endothelial injury remain poorly understood. We demonstrate here that endothelial ADAM10 was essential for the pathogenesis of Staphylococcus aureus sepsis, contributing to α-toxin-mediated (Hla-mediated) microvascular thrombus formation and lethality. As ADAM10 is essential for endothelial development and homeostasis, we examined whether other major human sepsis pathogens also rely on ADAM10-dependent pathways in pathogenesis. Mice harboring an endothelium-specific knockout of ADAM10 were protected against lethal Pseudomonas aeruginosa and Streptococcus pneumoniae sepsis, yet remained fully susceptible to group B streptococci and Candida albicans sepsis. These studies illustrate a previously unknown role for ADAM10 in sepsis-associated endothelial injury and suggest that understanding pathogen-specific divergent host pathways in sepsis may enable more precise targeting of disease.
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Affiliation(s)
| | - Mark J. Miller
- Division of Infectious Diseases, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
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4
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Kopenhagen A, Ramming I, Camp B, Hammerschmidt S, Fulde M, Müsken M, Steinert M, Bergmann S. Streptococcus pneumoniae Affects Endothelial Cell Migration in Microfluidic Circulation. Front Microbiol 2022; 13:852036. [PMID: 35401456 PMCID: PMC8990767 DOI: 10.3389/fmicb.2022.852036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 02/04/2022] [Indexed: 01/12/2023] Open
Abstract
Bloodstream infections caused by Streptococcus pneumoniae induce strong inflammatory and procoagulant cellular responses and affect the endothelial barrier of the vascular system. Bacterial virulence determinants, such as the cytotoxic pore-forming pneumolysin, increase the endothelial barrier permeability by inducing cell apoptosis and cell damage. As life-threatening consequences, disseminated intravascular coagulation followed by consumption coagulopathy and low blood pressure is described. With the aim to decipher the role of pneumolysin in endothelial damage and leakage of the vascular barrier in more detail, we established a chamber-separation cell migration assay (CSMA) used to illustrate endothelial wound healing upon bacterial infections. We used chambered inlets for cell cultivation, which, after removal, provide a cell-free area of 500 μm in diameter as a defined gap in primary endothelial cell layers. During the process of wound healing, the size of the cell-free area is decreasing due to cell migration and proliferation, which we quantitatively determined by microscopic live cell monitoring. In addition, differential immunofluorescence staining combined with confocal microscopy was used to morphologically characterize the effect of bacterial attachment on cell migration and the velocity of gap closure. In all assays, the presence of wild-type pneumococci significantly inhibited endothelial gap closure. Remarkably, even in the presence of pneumolysin-deficient pneumococci, cell migration was significantly retarded. Moreover, the inhibitory effect of pneumococci on the proportion of cell proliferation versus cell migration within the process of endothelial gap closure was assessed by implementation of a fluorescence-conjugated nucleoside analogon. We further combined the endothelial CSMA with a microfluidic pump system, which for the first time enabled the microscopic visualization and monitoring of endothelial gap closure in the presence of circulating bacteria at defined vascular shear stress values for up to 48 h. In accordance with our CSMA results under static conditions, the gap remained cell free in the presence of circulating pneumococci in flow. Hence, our combined endothelial cultivation technique represents a complex in vitro system, which mimics the vascular physiology as close as possible by providing essential parameters of the blood flow to gain new insights into the effect of pneumococcal infection on endothelial barrier integrity in flow.
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Affiliation(s)
- Anna Kopenhagen
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany
| | - Isabell Ramming
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany.,Department of Infectious Diseases, Robert Koch Institute, Wernigerode, Germany
| | - Belinda Camp
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany.,Department of Pneumology, University Hospital Magdeburg, Magdeburg, Germany
| | - Sven Hammerschmidt
- Institute for Genetics and Functional Genomics, Department of Molecular Genetics and Infection Biology, Universität Greifswald, Greifswald, Germany
| | - Marcus Fulde
- Institute of Microbiology and Epizootics, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Mathias Müsken
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Michael Steinert
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany.,Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Simone Bergmann
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany
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5
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The Role of Von Willebrand Factor in the Pathogenesis of Pulmonary Vascular Thrombosis in COVID-19. Viruses 2022; 14:v14020211. [PMID: 35215805 PMCID: PMC8874644 DOI: 10.3390/v14020211] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/14/2022] [Accepted: 01/18/2022] [Indexed: 02/07/2023] Open
Abstract
The increased plasma levels of von Willebrand factor (VWF) in patients with COVID-19 was reported in many studies, and its correlation with disease severity and mortality suggest its important role in the pathogenesis of thrombosis in COVID-19. We performed histological and immunohistochemical studies of the lungs of 29 patients who died from COVID-19. We found a significant increase in the intensity of immunohistochemical reaction for VWF in the pulmonary vascular endothelium when the disease duration was more than 10 days. In the patients who had thrombotic complications, the VWF immunostaining in the pulmonary vascular endothelium was significantly more intense than in nonsurvivors without thrombotic complications. Duration of disease and thrombotic complications were found to be independent predictors of increased VWF immunostaining in the endothelium of pulmonary vessels. We also revealed that bacterial pneumonia was associated with increased VWF staining intensity in pulmonary arterial, arteriolar, and venular endothelium, while lung ventilation was an independent predictor of increased VWF immunostaining in arterial endothelium. The results of the study demonstrated an important role of endothelial VWF in the pathogenesis of thrombus formation in COVID-19.
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6
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Steinert M, Ramming I, Bergmann S. Impact of Von Willebrand Factor on Bacterial Pathogenesis. Front Med (Lausanne) 2020; 7:543. [PMID: 33015097 PMCID: PMC7494747 DOI: 10.3389/fmed.2020.00543] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 07/30/2020] [Indexed: 12/31/2022] Open
Abstract
Von Willebrand factor (VWF) is a mechano-sensitive protein with crucial functions in normal hemostasis, which are strongly dependant on the shear-stress mediated defolding and multimerization of VWF in the blood stream. Apart from bleeding disorders, higher plasma levels of VWF are often associated with a higher risk of cardiovascular diseases. Herein, the disease symptoms are attributed to the inflammatory response of the activated endothelium and share high similarities to the reaction of the host vasculature to systemic infections caused by pathogenic bacteria such as Staphylococcus aureus and Streptococcus pneumoniae. The bacteria recruit circulating VWF, and by binding to immobilized VWF on activated endothelial cells in blood flow, they interfere with the physiological functions of VWF, including platelet recruitment and coagulation. Several bacterial VWF binding proteins have been identified and further characterized by biochemical analyses. Moreover, the development of a combination of sophisticated cell culture systems simulating shear stress levels of the blood flow with microscopic visualization also provided valuable insights into the interaction mechanism between bacteria and VWF-strings. In vivo studies using mouse models of bacterial infection and zebrafish larvae provided evidence that the interaction between bacteria and VWF promotes bacterial attachment, coagulation, and thrombus formation, and thereby contributes to the pathophysiology of severe infectious diseases such as infective endocarditis and bacterial sepsis. This mini-review summarizes the current knowledge of the interaction between bacteria and the mechano-responsive VWF, and corresponding pathophysiological disease symptoms.
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Affiliation(s)
- Michael Steinert
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany.,Department of Infection Biology, Helmholtz Center for Infection Diseases, Braunschweig, Germany
| | - Isabell Ramming
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany
| | - Simone Bergmann
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany
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7
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Gutbier B, Neuhauß AK, Reppe K, Ehrler C, Santel A, Kaufmann J, Scholz M, Weissmann N, Morawietz L, Mitchell TJ, Aliberti S, Hippenstiel S, Suttorp N, Witzenrath M. Prognostic and Pathogenic Role of Angiopoietin-1 and -2 in Pneumonia. Am J Respir Crit Care Med 2019; 198:220-231. [PMID: 29447449 DOI: 10.1164/rccm.201708-1733oc] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
RATIONALE During pneumonia, pathogen-host interaction evokes inflammation and lung barrier dysfunction. Tie2 activation by angiopoietin-1 reduces, whereas Tie2 blockade by angiopoietin-2 increases, inflammation and permeability during sepsis. The role of angiopoietin-1/-2 in pneumonia remains unidentified. OBJECTIVES To investigate the prognostic and pathogenic impact of angiopoietins in regulating pulmonary vascular barrier function and inflammation in bacterial pneumonia. METHODS Serum angiopoietin levels were quantified in pneumonia patients of two independent cohorts (n = 148, n = 395). Human postmortem lung tissue, pneumolysin- or angiopoietin-2-stimulated endothelial cells, isolated perfused and ventilated mouse lungs, and mice with pneumococcal pneumonia were investigated. MEASUREMENTS AND MAIN RESULTS In patients with pneumonia, decreased serum angiopoietin-1 and increased angiopoietin-2 levels were observed as compared with healthy subjects. Higher angiopoietin-2 serum levels were found in patients with community-acquired pneumonia who died within 28 days of diagnosis compared with survivors. Receiver operating characteristic analysis revealed improved prognostic accuracy of CURB-65 for 28-day survival, intensive care treatment, and length of hospital stay if combined with angiopoietin-2 serum levels. In vitro, pneumolysin enhanced endothelial angiopoietin-2 release, angiopoietin-2 increased endothelial permeability, and angiopoietin-1 reduced pneumolysin-evoked endothelial permeability. Ventilated and perfused lungs of mice with angiopoietin-2 knockdown showed reduced permeability on pneumolysin stimulation. Increased pulmonary angiopoietin-2 and reduced angiopoietin-1 mRNA expression were observed in Streptococcus pneumoniae-infected mice. Finally, angiopoietin-1 therapy reduced inflammation and permeability in murine pneumonia. CONCLUSIONS These data suggest a central role of angiopoietin-1/-2 in pneumonia-evoked inflammation and permeability. Increased angiopoietin-2 serum levels predicted mortality and length of hospital stay, and angiopoietin-1 may provide a therapeutic target for severe pneumonia.
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Affiliation(s)
- Birgitt Gutbier
- 1 Division of Pulmonary Inflammation and.,2 Department of Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Anne-Kathrin Neuhauß
- 2 Department of Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Katrin Reppe
- 1 Division of Pulmonary Inflammation and.,2 Department of Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Carolin Ehrler
- 2 Department of Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | | | | | - Markus Scholz
- 4 Institute for Medical Informatics, Statistics and Epidemiology, University of Leipzig, Leipzig, Germany
| | - Norbert Weissmann
- 5 Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center, member of the German Center for Lung Research, Justus-Liebig-University, Giessen, Germany
| | - Lars Morawietz
- 6 Pathology, Healthcare Center Fuerstenberg-Karree, Berlin, Germany
| | - Timothy J Mitchell
- 7 Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Stefano Aliberti
- 8 Department of Pathophysiology and Transplantation, University of Milan, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Cà Granda Ospedale Maggiore Policlinico, Milan, Italy; and
| | - Stefan Hippenstiel
- 2 Department of Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Norbert Suttorp
- 2 Department of Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,9 CAPNETZ STIFTUNG, Hannover, Germany
| | - Martin Witzenrath
- 1 Division of Pulmonary Inflammation and.,2 Department of Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,9 CAPNETZ STIFTUNG, Hannover, Germany
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8
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Jagau H, Behrens IK, Lahme K, Lorz G, Köster RW, Schneppenheim R, Obser T, Brehm MA, König G, Kohler TP, Rohde M, Frank R, Tegge W, Fulde M, Hammerschmidt S, Steinert M, Bergmann S. Von Willebrand Factor Mediates Pneumococcal Aggregation and Adhesion in Blood Flow. Front Microbiol 2019; 10:511. [PMID: 30972039 PMCID: PMC6443961 DOI: 10.3389/fmicb.2019.00511] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 02/27/2019] [Indexed: 12/24/2022] Open
Abstract
Streptococcus pneumoniae is a major cause of community acquired pneumonia and septicaemia in humans. These diseases are frequently associated with thromboembolic cardiovascular complications. Pneumococci induce the exocytosis of endothelial Weibel-Palade Bodies and thereby actively stimulate the release of von Willebrand factor (VWF), which is an essential glycoprotein of the vascular hemostasis. Both, the pneumococcus induced pulmonary inflammation and the thromboembolytic complications are characterized by a dysbalanced hemostasis including a marked increase in VWF plasma concentrations. Here, we describe for the first time VWF as a novel interaction partner of capsulated and non-encapsulated pneumococci. Moreover, cell culture infection analyses with primary endothelial cells characterized VWF as bridging molecule that mediates bacterial adherence to endothelial cells in a heparin-sensitive manner. Due to the mechanoresponsive changes of the VWF protein conformation and multimerization status, which occur in the blood stream, we used a microfluidic pump system to generate shear flow-induced multimeric VWF strings on endothelial cell surfaces and analyzed attachment of RFP-expressing pneumococci in flow. By applying immunofluorescence visualization and additional electron microscopy, we detected a frequent and enduring bacterial attachment to the VWF strings. Bacterial attachment to the endothelium was confirmed in vivo using a zebrafish infection model, which is described in many reports and acknowledged as suitable model to study hemostasis mechanisms and protein interactions of coagulation factors. Notably, we visualized the recruitment of zebrafish-derived VWF to the surface of pneumococci circulating in the blood stream and detected a VWF-dependent formation of bacterial aggregates within the vasculature of infected zebrafish larvae. Furthermore, we identified the surface-exposed bacterial enolase as pneumococcal VWF binding protein, which interacts with the VWF domain A1 and determined the binding kinetics by surface plasmon resonance. Subsequent epitope mapping using an enolase peptide array indicates that the peptide 181YGAEIFHALKKILKS195 might serve as a possible core sequence of the VWF interaction site. In conclusion, we describe a VWF-mediated mechanism for pneumococcal anchoring within the bloodstream via surface-displayed enolase, which promotes intravascular bacterial aggregation.
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Affiliation(s)
- Hilger Jagau
- Institute of Microbiology, Technische Universität Braunschweig, Braunschweig, Germany
| | - Ina-Kristin Behrens
- Institute of Microbiology, Technische Universität Braunschweig, Braunschweig, Germany
| | - Karen Lahme
- Institute of Microbiology, Technische Universität Braunschweig, Braunschweig, Germany
| | - Georgina Lorz
- Institute of Microbiology, Technische Universität Braunschweig, Braunschweig, Germany
| | - Reinhard W Köster
- Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
| | - Reinhard Schneppenheim
- Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf (UKE Hamburg), Hamburg, Germany
| | - Tobias Obser
- Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf (UKE Hamburg), Hamburg, Germany
| | - Maria A Brehm
- Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf (UKE Hamburg), Hamburg, Germany
| | - Gesa König
- Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf (UKE Hamburg), Hamburg, Germany
| | - Thomas P Kohler
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Universität Greifswald, Greifswald, Germany
| | - Manfred Rohde
- Helmholtz Centre for Infection Research, Central Facility for Microscopy, Braunschweig, Germany
| | - Ronald Frank
- Department of Chemical Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Werner Tegge
- Department of Chemical Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Marcus Fulde
- Centre for Infection Medicine, Institute of Microbiology and Epizootics, Freie Universität Berlin, Berlin, Germany
| | - Sven Hammerschmidt
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Universität Greifswald, Greifswald, Germany
| | - Michael Steinert
- Institute of Microbiology, Technische Universität Braunschweig, Braunschweig, Germany.,Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Simone Bergmann
- Institute of Microbiology, Technische Universität Braunschweig, Braunschweig, Germany
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9
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Michels A, Swystun LL, Mewburn J, Albánez S, Lillicrap D. Investigating von Willebrand Factor Pathophysiology Using a Flow Chamber Model of von Willebrand Factor-platelet String Formation. J Vis Exp 2017. [PMID: 28829426 DOI: 10.3791/55917] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Von Willebrand factor (VWF) is a multimeric glycoprotein coagulation factor that mediates platelet adhesion and aggregation at sites of endothelial damage and that carries factor VIII in the circulation. VWF is synthesized by endothelial cells and is either released constitutively into the plasma or is stored in specialized organelles, called Weibel-Palade bodies (WPBs), for on-demand release in response to hemostatic challenge. Procoagulant and proinflammatory stimuli can rapidly induce WPB exocytosis and VWF release. The majority of VWF released by endothelial cells circulates in the plasma; however, a proportion of VWF is anchored to the endothelial cell surface. Under conditions of physiological shear, endothelial-anchored VWF can bind to platelets, forming a VWF-platelet string that may represent the nidus of thrombus formation. A flow chamber system can be used to visually observe the release of VWF from endothelial cells and the subsequent platelet capture in a manner that is reproducible and relevant to the pathophysiology of VWF-mediated thrombus formation. Using this methodology, endothelial cells are cultured in a flow chamber and are subsequently stimulated with secretagogues to induce WPB exocytosis. Washed platelets are then perfused over the activated endothelium. The platelets are activated and subsequently bind to elongated VWF strings in the direction of fluid flow. Using extracellular histones as a procoagulant and proinflammatory stimulus, we observed increased VWF-platelet string formation on histone-treated endothelial cells compared to untreated endothelial cells. This protocol describes a quantitative, visual, and real-time assessment of the activation of VWF-platelet interactions in models of thrombosis and hemostasis.
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Affiliation(s)
- Alison Michels
- Department of Pathology and Molecular Medicine, Queen's University
| | - Laura L Swystun
- Department of Pathology and Molecular Medicine, Queen's University
| | | | - Silvia Albánez
- Department of Pathology and Molecular Medicine, Queen's University
| | - David Lillicrap
- Department of Pathology and Molecular Medicine, Queen's University;
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10
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Berube BJ, Rangel SM, Hauser AR. Pseudomonas aeruginosa: breaking down barriers. Curr Genet 2015; 62:109-13. [PMID: 26407972 DOI: 10.1007/s00294-015-0522-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 09/15/2015] [Accepted: 09/16/2015] [Indexed: 12/26/2022]
Abstract
Many bacterial pathogens have evolved ingenious ways to escape from the lung during pneumonia to cause bacteremia. Unfortunately, the clinical consequences of this spread to the bloodstream are frequently dire. It is therefore important to understand the molecular mechanisms used by pathogens to breach the lung barrier. We have recently shown that Pseudomonas aeruginosa, one of the leading causes of hospital-acquired pneumonia, utilizes the type III secretion system effector ExoS to intoxicate pulmonary epithelial cells. Injection of these cells leads to localized disruption of the pulmonary-vascular barrier and dissemination of P. aeruginosa to the bloodstream. We put these data in the context of previous studies to provide a holistic model of P. aeruginosa dissemination from the lung. Finally, we compare P. aeruginosa dissemination to that of other bacteria to highlight the complexity of bacterial pneumonia. Although respiratory pathogens use distinct and intricate strategies to escape from the lungs, a thorough understanding of these processes can lay the foundation for new therapeutic approaches for bacterial pneumonia.
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Affiliation(s)
- Bryan J Berube
- Department of Microbiology-Immunology, Northwestern University, 303 E. Chicago Ave., Chicago, IL, 60611, USA
| | - Stephanie M Rangel
- Department of Microbiology-Immunology, Northwestern University, 303 E. Chicago Ave., Chicago, IL, 60611, USA
| | - Alan R Hauser
- Department of Microbiology-Immunology, Northwestern University, 303 E. Chicago Ave., Chicago, IL, 60611, USA. .,Department of Medicine, Northwestern University, Chicago, IL, USA.
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Bergmann S, Steinert M. From Single Cells to Engineered and Explanted Tissues: New Perspectives in Bacterial Infection Biology. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 319:1-44. [PMID: 26404465 DOI: 10.1016/bs.ircmb.2015.06.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cell culture techniques are essential for studying host-pathogen interactions. In addition to the broad range of single cell type-based two-dimensional cell culture models, an enormous amount of coculture systems, combining two or more different cell types, has been developed. These systems enable microscopic visualization and molecular analyses of bacterial adherence and internalization mechanisms and also provide a suitable setup for various biochemical, immunological, and pharmacological applications. The implementation of natural or synthetical scaffolds elevated the model complexity to the level of three-dimensional cell culture. Additionally, several transwell-based cell culture techniques are applied to study bacterial interaction with physiological tissue barriers. For keeping highly differentiated phenotype of eukaryotic cells in ex vivo culture conditions, different kinds of microgravity-simulating rotary-wall vessel systems are employed. Furthermore, the implementation of microfluidic pumps enables constant nutrient and gas exchange during cell cultivation and allows the investigation of long-term infection processes. The highest level of cell culture complexity is reached by engineered and explanted tissues which currently pave the way for a more comprehensive view on microbial pathogenicity mechanisms.
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Affiliation(s)
- Simone Bergmann
- Institute of Microbiology, Technische Universität Braunschweig, Braunschweig, Lower Saxony, Germany
| | - Michael Steinert
- Institute of Microbiology, Technische Universität Braunschweig, Braunschweig, Lower Saxony, Germany
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Streptococcus pneumoniae induces autophagy through the inhibition of the PI3K-I/Akt/mTOR pathway and ROS hypergeneration in A549 cells. PLoS One 2015; 10:e0122753. [PMID: 25803050 PMCID: PMC4372526 DOI: 10.1371/journal.pone.0122753] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 02/12/2015] [Indexed: 01/21/2023] Open
Abstract
The present study focused on the action mechanism of S. pneumoniae (Sp) in inducing autophagy in human alveolar epithelial cells. Sp, a gram-positive extracellular bacterium, activates autophagy with considerably increased microtuble-associated protein light chain 3 (LC3) punctation in A549 cells. The accumulation of typical autophagosomes and conjugation of LC3 to phosphatidylethanolamine were observed in Sp-infected cells as an indication of autophagy. Using the pneumolysin (PLY) mutant, we successfully demonstrated that PLY is involved in initiating autophagy without affecting the expression levels of PI3K-III and Beclin1. PLY-mediated autophagy depends on the inhibition of the phosphoinositide 3-kinase/Akt/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway. Furthermore, Sp could also lead to the reactive oxygen species (ROS) hypergeneration in A549 cells. Taken together, Sp infection-induced autophagy is PLY-mediated through ROS hypergeneration and mTOR inhibition. PI3K-I and rapamycin (autophagy inducers) enhanced bacterial clearance, whereas wortmannin (autophagy inhibitor) and acetylcysteine (ROS inhibitor) reduced intracellular bacteria clearance. Thus, Sp-induced autophagy represents a host-protective mechanism, providing new insight into the pathogenesis of respiratory tract Sp infection.
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Abstract
Cholesterol dependent cytolysins are important in the ability of some bacteria to cause disease in man and animals. Pneumolysin (PLY) plays a key role in the diseases caused by Streptococcus pneumoniae (the pneumococcus). This chapter describes the role of PLY in some of the key process in disease. These include induction of cell death by pore formation and toxin-induced apoptosis as well as more subtle effects on gene expression of host cells including epigenetic effects of the toxin. The use of bacterial mutants that either do not express the toxin or express altered versions in biological systems is described. Use of isolated tissue and whole animal systems to dissect the structure/function relationships of the toxin as well as the role played by different activities in the pathogenesis of infection are described. The role of PLY in meningitis and the associated deafness is discussed as well as the role of the toxin in promoting increased lung permeability and inflammation during pneumococcal pneumonia. Different clinical strains of the pneumococcus produce different forms of PLY and the impact of this on disease caused by these strains is discussed. Finally, the impact of this knowledge on the development of treatment and prevention strategies for pneumococcal disease is discussed.
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Kramko N, Sinitski D, Seebach J, Löffler B, Dieterich P, Heilmann C, Peters G, Schnittler HJ. Early Staphylococcus aureus-induced changes in endothelial barrier function are strain-specific and unrelated to bacterial translocation. Int J Med Microbiol 2013; 303:635-44. [DOI: 10.1016/j.ijmm.2013.09.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 08/26/2013] [Accepted: 09/01/2013] [Indexed: 12/14/2022] Open
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