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Sanford TC, Tweten RK, Abrahamsen HL. Bacterial cholesterol-dependent cytolysins and their interaction with the human immune response. Curr Opin Infect Dis 2024; 37:164-169. [PMID: 38527455 PMCID: PMC11042984 DOI: 10.1097/qco.0000000000001010] [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] [Indexed: 03/27/2024]
Abstract
PURPOSE OF REVIEW Many cholesterol-dependent cytolysin (CDC)-producing pathogens pose a significant threat to human health. Herein, we review the pore-dependent and -independent properties CDCs possess to assist pathogens in evading the host immune response. RECENT FINDINGS Within the last 5 years, exciting new research suggests CDCs can act to inhibit important immune functions, disrupt critical cell signaling pathways, and have tissue-specific effects. Additionally, recent studies have identified a key region of CDCs that generates robust immunity, providing resources for the development of CDC-based vaccines. SUMMARY This review provides new information on how CDCs alter host immune responses to aid bacteria in pathogenesis. These studies can assist in the design of more efficient vaccines and therapeutics against CDCs that will enhance the immune response to CDC-producing pathogens while mitigating the dampening effects CDCs have on the host immune response.
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Affiliation(s)
- Tristan C. Sanford
- University of Oklahoma Health Sciences Center, Department of Microbiology and Immunology, Oklahoma City, OK 73104
| | - Rodney K. Tweten
- University of Oklahoma Health Sciences Center, Department of Microbiology and Immunology, Oklahoma City, OK 73104
| | - Hunter L. Abrahamsen
- University of Oklahoma Health Sciences Center, Department of Microbiology and Immunology, Oklahoma City, OK 73104
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2
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Hoffet MS, Tomov NS, Hupp S, Mitchell TJ, Iliev AI. Glucose and Oxygen Levels Modulate the Pore-Forming Effects of Cholesterol-Dependent Cytolysin Pneumolysin from Streptococcus pneumoniae. Toxins (Basel) 2024; 16:232. [PMID: 38922127 PMCID: PMC11209487 DOI: 10.3390/toxins16060232] [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: 03/08/2024] [Revised: 05/08/2024] [Accepted: 05/16/2024] [Indexed: 06/27/2024] Open
Abstract
A major Streptococcus pneumoniae pathogenic factor is the cholesterol-dependent cytolysin pneumolysin, binding membrane cholesterol and producing permanent lytic or transient pores. During brain infections, vascular damage with variable ischemia occurs. The role of ischemia on pneumolysin's pore-forming capacity remains unknown. In acute brain slice cultures and primary cultured glia, we studied acute toxin lysis (via propidium iodide staining and LDH release) and transient pore formation (by analyzing increases in the intracellular calcium). We analyzed normal peripheral tissue glucose conditions (80 mg%), normal brain glucose levels (20 mg%), and brain hypoglycemic conditions (3 mg%), in combinations either with normoxia (8% oxygen) or hypoxia (2% oxygen). At 80 mg% glucose, hypoxia enhanced cytolysis via pneumolysin. At 20 mg% glucose, hypoxia did not affect cell lysis, but impaired calcium restoration after non-lytic pore formation. Only at 3 mg% glucose, during normoxia, did pneumolysin produce stronger lysis. In hypoglycemic (3 mg% glucose) conditions, pneumolysin caused a milder calcium increase, but restoration was missing. Microglia bound more pneumolysin than astrocytes and demonstrated generally stronger calcium elevation. Thus, our work demonstrated that the toxin pore-forming capacity in cells continuously diminishes when oxygen is reduced, overlapping with a continuously reduced ability of cells to maintain homeostasis of the calcium influx once oxygen and glucose are reduced.
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Affiliation(s)
- Michelle Salomé Hoffet
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012 Bern, Switzerland; (M.S.H.); (N.S.T.); (S.H.)
| | - Nikola S. Tomov
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012 Bern, Switzerland; (M.S.H.); (N.S.T.); (S.H.)
| | - Sabrina Hupp
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012 Bern, Switzerland; (M.S.H.); (N.S.T.); (S.H.)
| | - Timothy J. Mitchell
- School of Immunity and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK;
| | - Asparouh I. Iliev
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012 Bern, Switzerland; (M.S.H.); (N.S.T.); (S.H.)
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3
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Jennert F, Schaaf D, Nau R, Kohler TP, Hammerschmidt S, Häusler D, Valentin-Weigand P, Seele J. Hydrogen peroxide is responsible for the cytotoxic effects of Streptococcus pneumoniae on primary microglia in the absence of pneumolysin. J Innate Immun 2024; 16:000536514. [PMID: 38569474 PMCID: PMC11060703 DOI: 10.1159/000536514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 01/25/2024] [Indexed: 04/05/2024] Open
Abstract
INTRODUCTION Streptococcus pneumoniae is the most common cause of bacterial meningitis and meningoencephalitis in humans. The bacterium produces numerous virulence determinants, among them hydrogen peroxide (H2O2) and pneumolysin (Ply), which contribute to bacterial cytotoxicity. Microglia, the resident phagocytes in the brain, are distinct from other macrophages, and we thus compared their susceptibility to pneumococcal toxicity and their ability to phagocytose pneumococci with those of bone marrow-derived macrophages (BMDM). METHODS Microglia and BMDM were co-incubated with S. pneumoniae D39 to analyze survival of phagocytes by fluorescence microscopy, bacterial growth by quantitative plating, and phagocytosis by an antibiotic protection assay. Ply was detected by hemolysis assay and Western blot analysis. RESULTS We found that microglia were killed during pneumococcal infection with a wild-type and an isogenic ply-deficient mutant, whereas viability of BMDM was not affected by pneumococci. Treatment with recombinant Ply showed a dose-dependent cytotoxic effect on microglia and BMDM. However, high concentrations of recombinant Ply were required and under the chosen experimental conditions, Ply was not detectable in the supernatant during infection of microglia. Inactivation of H2O2 by exogenously added catalase abolished its cytotoxic effect. Consequently, infection of microglia with pneumococci deficient for the pyruvate oxidase SpxB, primarily producing H2O2, resulted in reduced killing of microglia. CONCLUSION Taken together, in the absence of Ply, H2O2 caused cell death in primary phagocytes in concentrations produced by pneumococci.
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Affiliation(s)
- Franziska Jennert
- University of Veterinary Medicine Hannover, Institute for Microbiology, Center for Infection Medicine, Hannover, Germany
| | - Désirée Schaaf
- University of Veterinary Medicine Hannover, Institute for Microbiology, Center for Infection Medicine, Hannover, Germany
| | - Roland Nau
- University Medical Center Göttingen, Department of Neuropathology, Göttingen, Germany
- Evangelisches Krankenhaus Göttingen-Weende, Department of Geriatrics, Göttingen, Germany
| | - Thomas P. Kohler
- Greifswald University, Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Greifswald, Germany
| | - Sven Hammerschmidt
- Greifswald University, Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Greifswald, Germany
| | - Darius Häusler
- University Medical Center Göttingen, Department of Neuropathology, Göttingen, Germany
- Fraunhofer-Institute for Translational Medicine and Pharmacology ITMP, Göttingen, Germany
| | - Peter Valentin-Weigand
- University of Veterinary Medicine Hannover, Institute for Microbiology, Center for Infection Medicine, Hannover, Germany
| | - Jana Seele
- University Medical Center Göttingen, Department of Neuropathology, Göttingen, Germany
- Evangelisches Krankenhaus Göttingen-Weende, Department of Geriatrics, Göttingen, Germany
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4
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Mondemé M, Zeroual Y, Soulard D, Hennart B, Beury D, Saliou JM, Carnoy C, Sirard JC, Faveeuw C. Amoxicillin treatment of pneumococcal pneumonia impacts bone marrow neutrophil maturation and function. J Leukoc Biol 2024; 115:463-475. [PMID: 37837383 DOI: 10.1093/jleuko/qiad125] [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: 07/06/2023] [Revised: 09/08/2023] [Accepted: 09/26/2023] [Indexed: 10/16/2023] Open
Abstract
Pneumonia caused by Streptococcus pneumoniae is a leading cause of death worldwide. A growing body of evidence indicates that the successful treatment of bacterial infections results from synergy between antibiotic-mediated direct antibacterial activity and the host's immune defenses. However, the mechanisms underlying the protective immune responses induced by amoxicillin, a β-lactam antibiotic used as the first-line treatment of S. pneumoniae infections, have not been characterized. A better understanding of amoxicillin's effects on host-pathogen interactions might facilitate the development of other treatment options. Given the crucial role of neutrophils in the control of S. pneumoniae infections, we decided to investigate amoxicillin's impact on neutrophil development in a mouse model of pneumococcal superinfection. A single therapeutic dose of amoxicillin almost completely eradicated the bacteria and prevented local and systemic inflammatory responses. Interestingly, in this context, amoxicillin treatment did not impair the emergency granulopoiesis triggered in the bone marrow by S. pneumoniae. Importantly, treatment of pneumonia with amoxicillin was associated with a greater mature neutrophil count in the bone marrow; these neutrophils had specific transcriptomic and proteomic profiles. Furthermore, amoxicillin-conditioned, mature neutrophils in the bone marrow had a less activated phenotype and might be rapidly mobilized in peripheral tissues in response to systemic inflammation. Thus, by revealing a novel effect of amoxicillin on the development and functions of bone marrow neutrophils during S. pneumoniae pneumonia, our findings provide new insights into the impact of amoxicillin treatment on host immune responses.
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Affiliation(s)
- Mélanie Mondemé
- Université de Lille, CNRS, Inserm, Centre Hospitalier Universitaire de Lille, Institut Pasteur de Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, Lille F-59019, France
| | - Yasmine Zeroual
- Université de Lille, CNRS, Inserm, Centre Hospitalier Universitaire de Lille, Institut Pasteur de Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, Lille F-59019, France
| | - Daphnée Soulard
- Université de Lille, CNRS, Inserm, Centre Hospitalier Universitaire de Lille, Institut Pasteur de Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, Lille F-59019, France
| | - Benjamin Hennart
- Toxicology and Genopathy Unit, Centre Hospitalier Universitaire de Lille, Lille F-59000, France
| | - Delphine Beury
- Université de Lille, CNRS, Inserm, Centre Hospitalier Universitaire de Lille, Institut Pasteur de Lille, US 41 - UAR 2014 - Plateformes Lilloises de Biologie et Santé, Lille F-59000, France
| | - Jean-Michel Saliou
- Université de Lille, CNRS, Inserm, Centre Hospitalier Universitaire de Lille, Institut Pasteur de Lille, US 41 - UAR 2014 - Plateformes Lilloises de Biologie et Santé, Lille F-59000, France
| | - Christophe Carnoy
- Université de Lille, CNRS, Inserm, Centre Hospitalier Universitaire de Lille, Institut Pasteur de Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, Lille F-59019, France
| | - Jean-Claude Sirard
- Université de Lille, CNRS, Inserm, Centre Hospitalier Universitaire de Lille, Institut Pasteur de Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, Lille F-59019, France
| | - Christelle Faveeuw
- Université de Lille, CNRS, Inserm, Centre Hospitalier Universitaire de Lille, Institut Pasteur de Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, Lille F-59019, France
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5
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Targeting the Inside of Cells with Biologicals: Toxin Routes in a Therapeutic Context. BioDrugs 2023; 37:181-203. [PMID: 36729328 PMCID: PMC9893211 DOI: 10.1007/s40259-023-00580-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/12/2023] [Indexed: 02/03/2023]
Abstract
Numerous toxins translocate to the cytosol in order to fulfil their function. This demonstrates the existence of routes for proteins from the extracellular space to the cytosol. Understanding these routes is relevant to multiple aspects related to therapeutic applications. These include the development of anti-toxin treatments, the potential use of toxins as shuttles for delivering macromolecular cargo to the cytosol or the use of drugs based on toxins. Compared with other strategies for delivery, such as chemicals as carriers for macromolecular delivery or physical methods like electroporation, toxin routes present paths into the cell that potentially cause less damage and can be specifically targeted. The efficiency of delivery via toxin routes is limited. However, low-delivery efficiencies can be entirely sufficient, if delivered cargoes possess an amplification effect or if very few molecules are sufficient for inducing the desired effects. This is known for example from RNA-based vaccines that have been developed during the coronavirus disease 2019 pandemic as well as for other approved RNA-based drugs, which elicited the desired effect despite their typically low delivery efficiencies. The different mechanisms by which toxins enter cells may have implications for their technological utility. We review the mechanistic principles of the translocation pathway of toxins from the extracellular space to the cytosol, the delivery efficiencies, and therapeutic strategies or applications that exploit toxin routes for intracellular delivery.
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6
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Treatment of Bacterial Infections with β-Lactams: Cooperation with Innate Immunity. Infect Immun 2023; 91:e0050322. [PMID: 36695576 PMCID: PMC9933636 DOI: 10.1128/iai.00503-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
β-Lactams are the most widely prescribed antibiotics used for the control and treatment of bacterial infections. The direct effect of β-lactams on bacteria is well studied worldwide. In the context of infections and as a consequence of their direct activity against the pathogen, β-lactams also regulate antibacterial immune responses. This knowledge has led to the theorem that the effectiveness of β-lactam treatment results from the synergy between the drug and the immune response. Key players in this immune response, with an essential role in the clearance of live and dead bacteria, are the myeloid cells. In this review, we summarize the data that shed light on how β-lactams interact with myeloid cells during bacterial infection treatment.
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7
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Cho SJ, Pronko A, Yang J, Pagan K, Stout-Delgado H. Role of Cholesterol 25-Hydroxylase (Ch25h) in Mediating Innate Immune Responses to Streptococcus pneumoniae Infection. Cells 2023; 12:570. [PMID: 36831236 PMCID: PMC9953875 DOI: 10.3390/cells12040570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/02/2023] [Accepted: 02/09/2023] [Indexed: 02/12/2023] Open
Abstract
Alveolar macrophages (AM) are long-lived tissue-resident innate immune cells of the airways. AM are key effectors of recognition, initiation, and resolution of the host defense against microbes and play an essential role in mediating host responses to Streptococcus pneumoniae infection. Lipid metabolism in AM can significantly impact cellular function and biology. Dysregulated metabolism contributes to an accumulation of lipids, unfolded protein response induction, and inflammatory cytokine production. Our study was designed to investigate the impact of Ch25h on mediating innate immune responses by macrophages during S. pneumoniae infection. Using wild-type and Ch25-/- mice, we examined the role of cholesterol metabolism on inflammatory cytokine production and bacterial clearance. Our results demonstrate that Ch25h plays an important role in the initiation and intensity of cytokine and chemokine production in the lung during S. pneumoniae infection. In the absence of Ch25h, there was enhanced phagocytosis and bacterial clearance. Taken together, our findings demonstrate the important role of Ch25h in modulating host responsiveness to S. pneumoniae infection.
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8
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Oehmcke-Hecht S, Maletzki C, Surabhi S, Siemens N, Khaimov V, John LM, Peter SM, Hammerschmidt S, Kreikemeyer B. Procoagulant Activity of Blood and Microvesicles Is Disturbed by Pneumococcal Pneumolysin, Which Interacts with Coagulation Factors. J Innate Immun 2022; 15:136-152. [PMID: 35843205 PMCID: PMC10643893 DOI: 10.1159/000525479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 06/06/2022] [Indexed: 11/17/2023] Open
Abstract
The coagulation and contact systems are parts of the innate immune system as they prevent bleeding and dissemination of pathogens and also contribute to microbial killing by inflammatory reactions and the release of antimicrobial peptides. Here, we investigated the influence of Streptococcus pneumoniae on the coagulation and contact system. S. pneumoniae (pneumococci), but no other investigated streptococcal species, impairs coagulation of blood by autolysis and release of pneumolysin. Defective blood coagulation results from the lysis of tissue factor-producing mononuclear cells and their procoagulant microvesicles, which are the main trigger for blood coagulation during sepsis. In addition, pneumolysin binds coagulation and contact system factors, but this does not result in activation. Thus, pneumococci modulate activation of the coagulation system by releasing pneumolysin, which could potentiate lung injury during pneumonia.
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Affiliation(s)
- Sonja Oehmcke-Hecht
- Institute of Medical Microbiology, Virology and Hygiene, Rostock University Medical Center, Rostock, Germany
| | - Claudia Maletzki
- Department of Medicine, Clinic III-Hematology, Oncology, Palliative Medicine, Rostock University Medical Center, Rostock, Germany
| | - Surabhi Surabhi
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Nikolai Siemens
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Valeria Khaimov
- Institute for ImplantTechnology and Biomaterials e.V., Rostock, Germany
| | - Lisa Marie John
- Institute of Medical Microbiology, Virology and Hygiene, Rostock University Medical Center, Rostock, Germany
| | - Sina Mariella Peter
- Institute of Medical Microbiology, Virology and Hygiene, Rostock University Medical Center, Rostock, Germany
| | - Sven Hammerschmidt
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Bernd Kreikemeyer
- Institute of Medical Microbiology, Virology and Hygiene, Rostock University Medical Center, Rostock, Germany
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9
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Pereira JM, Xu S, Leong JM, Sousa S. The Yin and Yang of Pneumolysin During Pneumococcal Infection. Front Immunol 2022; 13:878244. [PMID: 35529870 PMCID: PMC9074694 DOI: 10.3389/fimmu.2022.878244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 03/23/2022] [Indexed: 12/15/2022] Open
Abstract
Pneumolysin (PLY) is a pore-forming toxin produced by the human pathobiont Streptococcus pneumoniae, the major cause of pneumonia worldwide. PLY, a key pneumococcal virulence factor, can form transmembrane pores in host cells, disrupting plasma membrane integrity and deregulating cellular homeostasis. At lytic concentrations, PLY causes cell death. At sub-lytic concentrations, PLY triggers host cell survival pathways that cooperate to reseal the damaged plasma membrane and restore cell homeostasis. While PLY is generally considered a pivotal factor promoting S. pneumoniae colonization and survival, it is also a powerful trigger of the innate and adaptive host immune response against bacterial infection. The dichotomy of PLY as both a key bacterial virulence factor and a trigger for host immune modulation allows the toxin to display both "Yin" and "Yang" properties during infection, promoting disease by membrane perforation and activating inflammatory pathways, while also mitigating damage by triggering host cell repair and initiating anti-inflammatory responses. Due to its cytolytic activity and diverse immunomodulatory properties, PLY is integral to every stage of S. pneumoniae pathogenesis and may tip the balance towards either the pathogen or the host depending on the context of infection.
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Affiliation(s)
- Joana M. Pereira
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Molecular and Cellular (MC) Biology PhD Program, ICBAS - Instituto de Ciência Biomédicas Abel Salazar, University of Porto, Porto, Portugal
| | - Shuying Xu
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, United States
- Graduate Program in Immunology, Tufts Graduate School of Biomedical Sciences, Boston, MA, United States
| | - John M. Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, United States
| | - Sandra Sousa
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
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10
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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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11
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Neutrophil-Derived Extracellular Vesicles Activate Platelets after Pneumolysin Exposure. Cells 2021; 10:cells10123581. [PMID: 34944089 PMCID: PMC8700313 DOI: 10.3390/cells10123581] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 12/13/2021] [Accepted: 12/14/2021] [Indexed: 12/12/2022] Open
Abstract
Pneumolysin (PLY) is a pore-forming toxin of Streptococcus pneumoniae that contributes substantially to the inflammatory processes underlying pneumococcal pneumonia and lung injury. Host responses against S. pneumoniae are regulated in part by neutrophils and platelets, both individually and in cooperative interaction. Previous studies have shown that PLY can target both neutrophils and platelets, however, the mechanisms by which PLY directly affects these cells and alters their interactions are not completely understood. In this study, we characterize the effects of PLY on neutrophils and platelets and explore the mechanisms by which PLY may induce neutrophil–platelet interactions. In vitro studies demonstrated that PLY causes the formation of neutrophil extracellular traps (NETs) and the release of extracellular vesicles (EVs) from both human and murine neutrophils. In vivo, neutrophil EV (nEV) levels were increased in mice infected with S. pneumoniae. In platelets, treatment with PLY induced the cell surface expression of P-selectin (CD62P) and binding to annexin V and caused a significant release of platelet EVs (pl-EVs). Moreover, PLY-induced nEVs but not NETs promoted platelet activation. The pretreatment of nEVs with proteinase K inhibited platelet activation, indicating that the surface proteins of nEVs play a role in this process. Our findings demonstrate that PLY activates neutrophils and platelets to release EVs and support an important role for neutrophil EVs in modulating platelet functions in pneumococcal infections.
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12
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Wiebe F, Handtke S, Wesche J, Schnarre A, Palankar R, Wolff M, Jahn K, Voß F, Weißmüller S, Schüttrumpf J, Greinacher A, Hammerschmidt S. Polyvalent immunoglobulin preparations inhibit pneumolysin-induced platelet destruction. Thromb Haemost 2021; 122:1147-1158. [PMID: 34918314 PMCID: PMC9385248 DOI: 10.1055/a-1723-1880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Platelets play an important role in the development and progression of respiratory distress. Functional platelets are known to seal inflammatory endothelial gaps and loss of platelet function has been shown to result in loss of integrity of pulmonary vessels. This leads to fluid accumulation in the pulmonary interstitium, eventually resulting in respiratory distress.
Streptococcus pneumoniae
is one of the major pathogens causing community-acquired pneumonia. Previously, we have shown that its major toxin pneumolysin forms pores in platelet membranes and renders them nonfunctional. In vitro, this process was inhibited by polyvalent intravenous immunoglobulins (IVIGs). In this study, we compared the efficacy of a standard IVIG preparation (IVIG, 98% immunoglobulin G [IgG]; Privigen, CSL Behring, United States) and an IgM/IgA-enriched immunoglobulin preparation (21% IgA, 23% IgM, 56% IgG; trimodulin, Biotest AG, Germany) to inhibit pneumolysin-induced platelet destruction. Platelet destruction and functionality were assessed by flow cytometry, intracellular calcium release, aggregometry, platelet viability, transwell, and flow chamber assays. Overall, both immunoglobulin preparations efficiently inhibited pneumolysin-induced platelet destruction. The capacity to antagonize pneumolysin mainly depended on the final IgG content. As both polyvalent immunoglobulin preparations efficiently prevent pneumolysin-induced platelet destruction and maintain platelet function in vitro, they represent promising candidates for clinical studies on supportive treatment of pneumococcal pneumonia to reduce progression of respiratory distress.
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Affiliation(s)
- Friederike Wiebe
- Department of Transfusion Medicine, Institute of Immunology and Transfusion Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Stefan Handtke
- Department of Transfusion Medicine, Institute of Immunology and Transfusion Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Jan Wesche
- Department of Transfusion Medicine, Institute of Immunology and Transfusion Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Annabel Schnarre
- Department of Transfusion Medicine, Institute of Immunology and Transfusion Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Raghavendra Palankar
- Department of Transfusion Medicine, Institute of Immunology and Transfusion Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Martina Wolff
- Department of Transfusion Medicine, Institute of Immunology and Transfusion Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Kristin Jahn
- Department of Molecular Genetics and Infection Biology, Universität Greifswald Mathematisch-Naturwissenschaftliche Fakultät, Greifswald, Germany
| | - Franziska Voß
- Department of Molecular Genetics and Infection Biology, Universität Greifswald Mathematisch-Naturwissenschaftliche Fakultät, Greifswald, Germany
| | | | - Jörg Schüttrumpf
- Department of Research & Development, Biotest AG, Dreieich, Germany
| | - Andreas Greinacher
- Department of Transfusion Medicine, Institute of Immunology and Transfusion Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Sven Hammerschmidt
- Department of Molecular Genetics and Infection Biology, Universität Greifswald Mathematisch-Naturwissenschaftliche Fakultät, Greifswald, Germany
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13
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Intracellularly Released Cholesterol from Polymer-Based Delivery Systems Alters Cellular Responses to Pneumolysin and Promotes Cell Survival. Metabolites 2021; 11:metabo11120821. [PMID: 34940579 PMCID: PMC8709088 DOI: 10.3390/metabo11120821] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/19/2021] [Accepted: 11/22/2021] [Indexed: 11/30/2022] Open
Abstract
Cholesterol is highly abundant within all human body cells and modulates critical cellular functions related to cellular plasticity, metabolism, and survival. The cholesterol-binding toxin pneumolysin represents an essential virulence factor of Streptococcus pneumoniae in establishing pneumonia and other pneumococcal infections. Thus, cholesterol scavenging of pneumolysin is a promising strategy to reduce S. pneumoniae induced lung damage. There may also be a second cholesterol-dependent mechanism whereby pneumococcal infection and the presence of pneumolysin increase hepatic sterol biosynthesis. Here we investigated a library of polymer particles varying in size and composition that allow for the cellular delivery of cholesterol and their effects on cell survival mechanisms following pneumolysin exposure. Intracellular delivery of cholesterol by nanocarriers composed of Eudragit E100–PLGA rescued pneumolysin-induced alterations of lipid homeostasis and enhanced cell survival irrespective of neutralization of pneumolysin.
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Miller RP, Berlouis ME, Hall AG, Simpson AHR, Smith IDM, Hall AC. Effects of Antibiotics on α-Toxin Levels during Staphylococcus aureus Culture: Implications for the Protection of Chondrocytes in a Model of Septic Arthritis. Cartilage 2021; 12:362-376. [PMID: 30762428 PMCID: PMC8236659 DOI: 10.1177/1947603519828433] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVE Septic arthritis results from joint infection by Staphylococcus aureus, which produces potent α-toxin causing cell death, potentially leading to permanent cartilage damage. Treatment is by joint irrigation and antibiotics, although it is unclear if, following treatment with antibiotics which cause bacterial lysis, there is release of additional stored α-toxin. DESIGN A rabbit erythrocyte hemolysis assay was optimised to assess biologically-active α-toxin from cultured S. aureus α-toxin strain DU5946. Hemoglobin release was measured spectrophotometrically following addition of a bacteriostatic antibiotic (linezolid) or a bacteriolytic antibiotic (penicillin). A bovine cartilage model of septic arthritis was used to test the protective effects of antibiotics against S. aureus infection. RESULTS During S. aureus culture, α-toxin levels increased rapidly but the rate of rise was quickly (within 20 minutes) suppressed by linezolid (25 μg/mL). Penicillin also reduced the increase in α-toxin levels; however, the time course was relatively slow compared to linezolid even at high concentrations (50,000 U/mL). The efficacy of penicillin (250,000 U/mL) at reducing the rise in α-toxin was approximately 8% less than that of linezolid (P < 0.05) suggesting the presence of additional toxin. This could be due to a delayed action of penicillin, and/or release of a small pool of stored α-toxin from dying bacteria. In a bovine cartilage model, however, there was no difference between the protection of in situ chondrocytes against S. aureus by penicillin or linezolid (P > 0.05). CONCLUSION The results suggested that equally effective protection of chondrocytes against S. aureus septic arthritis may be obtained by the bacteriostatic or bacteriolytic antibiotics tested.
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Affiliation(s)
- Robbie P. Miller
- Centre for Integrative Physiology, Deanery of Biomedical Sciences, University of Edinburgh, Edinburgh, Scotland, UK
| | - Marie E. Berlouis
- Centre for Integrative Physiology, Deanery of Biomedical Sciences, University of Edinburgh, Edinburgh, Scotland, UK
| | - Alan G. Hall
- Centre for Integrative Physiology, Deanery of Biomedical Sciences, University of Edinburgh, Edinburgh, Scotland, UK
| | - A. Hamish R.W. Simpson
- Musculoskeletal Research Unit, Department of Orthopaedic Surgery, University of Edinburgh, Edinburgh, Scotland, UK
| | - Innes D. M. Smith
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, Scotland, UK
| | - Andrew C. Hall
- Centre for Integrative Physiology, Deanery of Biomedical Sciences, University of Edinburgh, Edinburgh, Scotland, UK,Andrew C. Hall, Centre for Integrative Physiology, Deanery of Biomedical Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9AG, Scotland, UK
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15
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Pneumolysin induces platelet destruction, not platelet activation, which can be prevented by immunoglobulin preparations in vitro. Blood Adv 2021; 4:6315-6326. [PMID: 33351126 DOI: 10.1182/bloodadvances.2020002372] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 11/05/2020] [Indexed: 01/08/2023] Open
Abstract
Community-acquired pneumonia by primary or superinfections with Streptococcus pneumoniae can lead to acute respiratory distress requiring mechanical ventilation. The pore-forming toxin pneumolysin alters the alveolar-capillary barrier and causes extravasation of protein-rich fluid into the interstitial pulmonary tissue, which impairs gas exchange. Platelets usually prevent endothelial leakage in inflamed pulmonary tissue by sealing inflammation-induced endothelial gaps. We not only confirm that S pneumoniae induces CD62P expression in platelets, but we also show that, in the presence of pneumolysin, CD62P expression is not associated with platelet activation. Pneumolysin induces pores in the platelet membrane, which allow anti-CD62P antibodies to stain the intracellular CD62P without platelet activation. Pneumolysin treatment also results in calcium efflux, increase in light transmission by platelet lysis (not aggregation), loss of platelet thrombus formation in the flow chamber, and loss of pore-sealing capacity of platelets in the Boyden chamber. Specific anti-pneumolysin monoclonal and polyclonal antibodies inhibit these effects of pneumolysin on platelets as do polyvalent human immunoglobulins. In a post hoc analysis of the prospective randomized phase 2 CIGMA trial, we show that administration of a polyvalent immunoglobulin preparation was associated with a nominally higher platelet count and nominally improved survival in patients with severe S pneumoniae-related community-acquired pneumonia. Although, due to the low number of patients, no definitive conclusion can be made, our findings provide a rationale for investigation of pharmacologic immunoglobulin preparations to target pneumolysin by polyvalent immunoglobulin preparations in severe community-acquired pneumococcal pneumonia, to counteract the risk of these patients becoming ventilation dependent. This trial was registered at www.clinicaltrials.gov as #NCT01420744.
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16
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Streptococcus pneumoniae and Its Virulence Factors H 2O 2 and Pneumolysin Are Potent Mediators of the Acute Chest Syndrome in Sickle Cell Disease. Toxins (Basel) 2021; 13:toxins13020157. [PMID: 33671422 PMCID: PMC7922783 DOI: 10.3390/toxins13020157] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/08/2021] [Accepted: 02/11/2021] [Indexed: 01/27/2023] Open
Abstract
Sickle cell disease (SCD) is one of the most common autosomal recessive disorders in the world. Due to functional asplenia, a dysfunctional antibody response, antibiotic drug resistance and poor response to immunization, SCD patients have impaired immunity. A leading cause of hospitalization and death in SCD patients is the acute chest syndrome (ACS). This complication is especially manifested upon infection of SCD patients with Streptococcus pneumoniae (Spn)—a facultative anaerobic Gram-positive bacterium that causes lower respiratory tract infections. Spn has developed increased rates of antibiotics resistance and is particularly virulent in SCD patients. The primary defense against Spn is the generation of reactive oxygen species (ROS) during the oxidative burst of neutrophils and macrophages. Paradoxically, Spn itself produces high levels of the ROS hydrogen peroxide (H2O2) as a virulence strategy. Apart from H2O2, Spn also secretes another virulence factor, i.e., the pore-forming exotoxin pneumolysin (PLY), a potent mediator of lung injury in patients with pneumonia in general and particularly in those with SCD. PLY is released early on in infection either by autolysis or bacterial lysis following the treatment with antibiotics and has a broad range of biological activities. This review will discuss recent findings on the role of pneumococci in ACS pathogenesis and on strategies to counteract the devastating effects of its virulence factors on the lungs in SCD patients.
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17
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Nerlich A, von Wunsch Teruel I, Mieth M, Hönzke K, Rückert JC, Mitchell TJ, Suttorp N, Hippenstiel S, Hocke AC. Reversion of Pneumolysin-Induced Executioner Caspase Activation Redirects Cells to Survival. J Infect Dis 2020; 223:1973-1983. [PMID: 33045080 DOI: 10.1093/infdis/jiaa639] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 10/06/2020] [Indexed: 01/23/2023] Open
Abstract
Apoptosis is an indispensable mechanism for eliminating infected cells and activation of executioner caspases is considered to be a point of no return. Streptococcus pneumoniae, the most common bacterial pathogen causing community-acquired pneumonia, induces apoptosis via its pore-forming toxin pneumolysin, leading to rapid influxes of mitochondrial calcium [Ca2+]m as well as fragmentation, and loss of motility and membrane potential, which is accompanied by caspase-3/7 activation. Using machine-learning and quantitative live-cell microscopy, we identified a significant number of alveolar epithelial cells surviving such executioner caspase activation after pneumolysin attack. Precise single-cell analysis revealed the [Ca2+]m amplitude and efflux rate as decisive parameters for survival and death, which was verified by pharmacological inhibition of [Ca2+]m efflux shifting the surviving cells towards the dying fraction. Taken together, we identified the regulation of [Ca2+]m as critical for controlling the cellular fate under pneumolysin attack, which might be useful for therapeutic intervention during pneumococcal infection.
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Affiliation(s)
- Andreas Nerlich
- Department of Internal Medicine/Infectious Diseases and Respiratory Medicine, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Berlin, Germany.,Institute for Microbiology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Iris von Wunsch Teruel
- Department of Internal Medicine/Infectious Diseases and Respiratory Medicine, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Maren Mieth
- Department of Internal Medicine/Infectious Diseases and Respiratory Medicine, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Katja Hönzke
- Department of Internal Medicine/Infectious Diseases and Respiratory Medicine, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Jens C Rückert
- Department of General, Visceral, Vascular and Thoracic Surgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Timothy J Mitchell
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Norbert Suttorp
- Department of Internal Medicine/Infectious Diseases and Respiratory Medicine, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Stefan Hippenstiel
- Department of Internal Medicine/Infectious Diseases and Respiratory Medicine, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Andreas C Hocke
- Department of Internal Medicine/Infectious Diseases and Respiratory Medicine, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Berlin, Germany
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18
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Subramanian K, Iovino F, Tsikourkitoudi V, Merkl P, Ahmed S, Berry SB, Aschtgen MS, Svensson M, Bergman P, Sotiriou GA, Henriques-Normark B. Mannose receptor-derived peptides neutralize pore-forming toxins and reduce inflammation and development of pneumococcal disease. EMBO Mol Med 2020; 12:e12695. [PMID: 32985105 PMCID: PMC7645366 DOI: 10.15252/emmm.202012695] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 08/30/2020] [Accepted: 09/02/2020] [Indexed: 12/30/2022] Open
Abstract
Cholesterol‐dependent cytolysins (CDCs) are essential virulence factors for many human pathogens like Streptococcus pneumoniae (pneumolysin, PLY), Streptococcus pyogenes (streptolysin O, SLO), and Listeria monocytogenes (Listeriolysin, LLO) and induce cytolysis and inflammation. Recently, we identified that pneumococcal PLY interacts with the mannose receptor (MRC‐1) on specific immune cells thereby evoking an anti‐inflammatory response at sublytic doses. Here, we identified the interaction sites between MRC‐1 and CDCs using computational docking. We designed peptides from the CTLD4 domain of MRC‐1 that binds to PLY, SLO, and LLO, respectively. In vitro, the peptides blocked CDC‐induced cytolysis and inflammatory cytokine production by human macrophages. Also, they reduced PLY‐induced damage of the epithelial barrier integrity as well as blocked bacterial invasion into the epithelium in a 3D lung tissue model. Pre‐treatment of human DCs with peptides blocked bacterial uptake via MRC‐1 and reduced intracellular bacterial survival by targeting bacteria to autophagosomes. In order to use the peptides for treatment in vivo, we developed calcium phosphate nanoparticles (CaP NPs) as peptide nanocarriers for intranasal delivery of peptides and enhanced bioactivity. Co‐administration of peptide‐loaded CaP NPs during infection improved survival and bacterial clearance in both zebrafish and mice models of pneumococcal infection. We suggest that MRC‐1 peptides can be employed as adjunctive therapeutics with antibiotics to treat bacterial infections by countering the action of CDCs.
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Affiliation(s)
- Karthik Subramanian
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Federico Iovino
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Vasiliki Tsikourkitoudi
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Padryk Merkl
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Sultan Ahmed
- Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Samuel B Berry
- Department of Medicine, Center for Infectious Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden
| | | | - Mattias Svensson
- Department of Medicine, Center for Infectious Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden
| | - Peter Bergman
- Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden.,The Immunodeficiency Unit, Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Georgios A Sotiriou
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Birgitta Henriques-Normark
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.,Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden.,Lee Kong Chian School of Medicine (LKC) and Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore, Singapore
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19
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Fisher J, Pavan C, Ohlmeier LS, Nilson B, Lundgaard I, Linder A, Bentzer P. A functional observational battery for evaluation of neurological outcomes in a rat model of acute bacterial meningitis. Intensive Care Med Exp 2020; 8:40. [PMID: 32770475 PMCID: PMC7415049 DOI: 10.1186/s40635-020-00331-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 07/21/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Acute bacterial meningitis is a disease with a high mortality and a high incidence of neurological sequelae in survivors. There is an acute need to develop new adjuvant therapies. To ensure that new therapies evaluated in animal models are translatable to humans, studies must evaluate clinically relevant and patient-important outcomes, including neurological symptoms and sequelae. METHODS We developed and tested a functional observational battery to quantify the severity of a variety of relevant neurological and clinical symptoms in a rat model of bacterial meningitis. The functional observational battery included symptoms relating to general clinical signs, gait and posture abnormalities, involuntary motor movements, focal neurological signs, and neuromotor abnormalities which were scored according to severity and summed to obtain a combined clinical and neurological score. To test the functional observational battery, adult Sprague-Dawley rats were infected by intracisternal injection of a clinical isolate of Streptococcus pneumoniae. Rats were evaluated for 6 days following the infection. RESULTS Pneumococcal meningitis was not lethal in this model; however, it induced severe neurological symptoms. Most common symptoms were hearing loss (75% of infected vs 0% of control rats; p = 0.0003), involuntary motor movements (75% of infected vs 0% of control rats; p = 0.0003), and gait and posture abnormality (67% of infected vs 0% of control rats; p = 0.0013). Infected rats had a higher combined score when determined by the functional observational battery than control rats at all time points (24 h 12.7 ± 4.0 vs 4.0 ± 2.0; 48 h 17.3 ± 7.1 vs 3.4 ± 1.8; 6 days 17.8 ± 7.4 vs 1.7 ± 2.4; p < 0.0001 for all). CONCLUSIONS The functional observational battery described here detects clinically relevant neurological sequelae of bacterial meningitis and could be a useful tool when testing new therapeutics in rat models of meningitis.
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Affiliation(s)
- Jane Fisher
- Faculty of Medicine, Department of Clinical Sciences Lund, Division of Infection Medicine, Lund University, Lund, Sweden.
| | - Chiara Pavan
- Center for Translational Neuromedicine, Faculties of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Luisa S Ohlmeier
- Faculty of Medicine, Department of Clinical Sciences Lund, Division of Infection Medicine, Lund University, Lund, Sweden
| | - Bo Nilson
- Faculty of Medicine, Department of Laboratory Medicine, Division of Medical Microbiology Lund, Lund University, Lund, Sweden
- Clinical Microbiology, Labmedicin, Region Skåne, Lund, Sweden
| | - Iben Lundgaard
- Department of Experimental Medical Science, University of Lund, Lund, Sweden
- Wallenberg Center for Molecular Medicine, University of Lund, Lund, Sweden
| | - Adam Linder
- Faculty of Medicine, Department of Clinical Sciences Lund, Division of Infection Medicine, Lund University, Lund, Sweden
| | - Peter Bentzer
- Department of Anesthesia and Intensive Care, Helsingborg Hospital, Helsingborg, Sweden
- Division of Anesthesia and Intensive Care, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
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20
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Ye J, Chu AJ, Harper R, Chan ST, Shek TL, Zhang Y, Ip M, Sambir M, Artsimovitch I, Zuo Z, Yang X, Ma C. Discovery of Antibacterials That Inhibit Bacterial RNA Polymerase Interactions with Sigma Factors. J Med Chem 2020; 63:7695-7720. [PMID: 32633513 PMCID: PMC8091929 DOI: 10.1021/acs.jmedchem.0c00520] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Formation of a bacterial RNA polymerase (RNAP) holoenzyme by a catalytic core RNAP and a sigma (σ) initiation factor is essential for bacterial viability. As the primary binding site for the housekeeping σ factors, the RNAP clamp helix domain represents an attractive target for novel antimicrobial agent discovery. Previously, we designed a pharmacophore model based on the essential amino acids of the clamp helix, such as R278, R281, and I291 (Escherichia coli numbering), and identified hit compounds with antimicrobial activity that interfered with the core-σ interactions. In this work, we rationally designed and synthesized a class of triaryl derivatives of one hit compound and succeeded in drastically improving the antimicrobial activity against Streptococcus pneumoniae, with the minimum inhibitory concentration reduced from 256 to 1 μg/mL. Additional characterization of antimicrobial activity, inhibition of transcription, in vitro pharmacological properties, and cytotoxicity of the optimized compounds demonstrated their potential for further development.
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Affiliation(s)
- Jiqing Ye
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, People's Republic of China
| | - Adrian Jun Chu
- Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, People's Republic of China
| | - Rachel Harper
- Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, People's Republic of China
| | - Shu Ting Chan
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, People's Republic of China
| | - Tsun Lam Shek
- School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, People's Republic of China
| | - Yufeng Zhang
- School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, People's Republic of China
| | - Margaret Ip
- Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, People's Republic of China
| | - Mariya Sambir
- Department of Microbiology and the Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Irina Artsimovitch
- Department of Microbiology and the Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Zhong Zuo
- School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, People's Republic of China
| | - Xiao Yang
- Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, People's Republic of China
| | - Cong Ma
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, People's Republic of China
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21
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Pleckaityte M. Cholesterol-Dependent Cytolysins Produced by Vaginal Bacteria: Certainties and Controversies. Front Cell Infect Microbiol 2020; 9:452. [PMID: 31998661 PMCID: PMC6966277 DOI: 10.3389/fcimb.2019.00452] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 12/12/2019] [Indexed: 01/16/2023] Open
Abstract
Bacterial vaginosis (BV) is a vaginal anaerobic dysbiosis that affects women of reproductive age worldwide. BV is microbiologically characterized by the depletion of vaginal lactobacilli and the overgrowth of anaerobic bacterial species. Accumulated evidence suggests that Gardnerella spp. have a pivotal role among BV-associated bacteria in the initiation and development of BV. However, Gardnerella spp. often colonize healthy women. Lactobacillus iners is considered as a prevalent constituent of healthy vaginal microbiota, and is abundant in BV. Gardnerella spp. and L. iners secrete the toxins vaginolysin (VLY) and inerolysin (INY), which have structural and activity features attributed to cholesterol-dependent cytolysins (CDCs). CDCs are produced by many pathogenic bacteria as virulence factors that participate in various stages of disease progression by forming lytic and non-lytic pores in cell membranes or via pore-independent pathways. VLY is expressed in the majority of Gardnerella spp. isolates; less is known about the prevalence of the gene that encodes INY. INY is a classical CDC; membrane cholesterol acts a receptor for INY. VLY uses human CD59 as its receptor, although cholesterol remains indispensable for VLY pore-forming activity. INY-induced damage of artificial membranes is directly dependent on cholesterol concentration in the bilayer, whereas VLY-induced damage occurs with high levels of membrane cholesterol (>40 mol%). VLY primarily forms membrane-embedded complete rings in the synthetic bilayer, whereas INY forms arciform structures with smaller pore sizes. VLY activity is high at elevated pH, which is characteristic of BV, whereas INY activity is high at more acidic pH, which is specific for a healthy vagina. Increased VLY levels in vaginal mucosa in vivo were associated with clinical indicators of BV. However, experimental evidence is lacking for the specific roles of VLY and INY in BV. The interplay between vaginal bacterial species affects the expression of the gene encoding VLY, thereby modulating the virulence of Gardnerella spp. This review discusses the current evidence for VLY and INY cytolysins, including their structures and activities, factors affecting their expression, and their potential impacts on the progression of anaerobic dysbiosis.
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Affiliation(s)
- Milda Pleckaityte
- Laboratory of Immunology and Cell Biology, Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
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22
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Kietzman C, Tuomanen E. Acute Bacterial Meningitis: Challenges to Better Antibiotic Therapy. ACS Infect Dis 2019; 5:1987-1995. [PMID: 31268283 DOI: 10.1021/acsinfecdis.9b00122] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Bacterial meningitis is a medical emergency requiring highly bactericidal antibiotics to achieve cure. Many challenges exist to achieving optimal patient outcome. First, antibiotics must pass the blood brain barrier. Once in the subarachnoid space, achieving bactericidal therapy involves circumventing antibiotic resistance and, more commonly, antibiotic tolerance arising from the slow growth of bacteria in the nutrient poor cerebrospinal fluid. Finally, bactericidal therapy is most often bacteriolytic, and debris from lysis is highly inflammatory. Controlling damage from lytic products may require adjunctive therapy to prevent neuronal death. These challenges are an extreme example of the different requirements for treating infections in different body sites.
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Affiliation(s)
- Colin Kietzman
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, Tennessee 38105, United States
| | - Elaine Tuomanen
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, Tennessee 38105, United States
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23
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First-In-Class Inhibitors Targeting the Interaction between Bacterial RNA Polymerase and Sigma Initiation Factor Affect the Viability and Toxin Release of Streptococcus pneumoniae. Molecules 2019; 24:molecules24162902. [PMID: 31405060 PMCID: PMC6719014 DOI: 10.3390/molecules24162902] [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: 07/15/2019] [Revised: 08/07/2019] [Accepted: 08/08/2019] [Indexed: 11/16/2022] Open
Abstract
Novel antimicrobial classes are in desperate need for clinical management of infections caused by increasingly prevalent multi-drug resistant pathogens. The protein-protein interaction between bacterial RNA polymerase (RNAP) and the housekeeping sigma initiation factor is essential to transcription and bacterial viability. It also presents a potential target for antimicrobial discovery, for which a hit compound (C3) was previously identified from a pharmacophore model-based in silico screen. In this study, the hit compound was experimentally assessed with some rationally designed derivatives for the antimicrobial activities, in particular against Streptococcus pneumoniae and other pathogens. One compound, C3-005, shows dramatically improved activity against pneumococci compared to C3. C3-005 also attenuates S. pneumoniae toxin production more strongly than existing classes of antibiotics tested. Here we demonstrate a newly validated antimicrobial agent to address an overlooked target in the hit-to-lead process, which may pave the way for further antimicrobial development.
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Hupp S, Grandgirard D, Mitchell TJ, Leib SL, Hathaway LJ, Iliev AI. Pneumolysin and the bacterial capsule of Streptococcus pneumoniae cooperatively inhibit taxis and motility of microglia. J Neuroinflammation 2019; 16:105. [PMID: 31103037 PMCID: PMC6525981 DOI: 10.1186/s12974-019-1491-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 04/30/2019] [Indexed: 01/11/2023] Open
Abstract
Background Streptococcus pneumoniae is the cause of a highly lethal form of meningitis in humans. Microglial cells in the brain represent the first line of defense against pathogens, and they participate in the inflammatory response. The cholesterol-dependent cytolysin pneumolysin and the bacterial capsule are key pathogenic factors, known to exacerbate the course of pneumococcal meningitis. Methods We utilized live imaging and immunostaining of glial cells in dissociated and acute brain slice cultures to study the effect of pneumococcal factors, including the cholesterol-dependent cytolysin pneumolysin and the pneumococcal capsule, on microglial motility and taxis. Results In brain tissue, primary microglia cells showed an enhanced response towards lysates from bacteria lacking capsules and pneumolysin as they moved rapidly to areas with an abundance of bacterial factors. The presence of bacterial capsules and pneumolysin cumulatively inhibited microglial taxis. In mixed cultures of astrocytes and microglia, the motility of microglia was inhibited by capsular components within minutes after exposure. The reduced motility was partially reversed by mannan, a mannose receptor inhibitor. The effects on microglia were not mediated by astrocytes because pure microglial cells responded to various pneumococcal lysates similarly with distinct cell shape changes as seen in mixed cultures. Conclusions Our data indicate that microglia possess the capacity for a very agile response towards bacterial pathogens, but key pathogenic factors, such as pneumococcal capsules and pneumolysin, inhibited this response shortly after a bacterial challenge. Furthermore, we demonstrate for the first time that the bacterial capsule affects cellular behaviors such as motility and taxis. Electronic supplementary material The online version of this article (10.1186/s12974-019-1491-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sabrina Hupp
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012, Bern, Switzerland
| | - Denis Grandgirard
- Institute for Infectious Diseases, University of Bern, Friedbühlstrasse 51, 3010, Bern, Switzerland
| | - Timothy J Mitchell
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, Biosciences Building, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Stephen L Leib
- Institute for Infectious Diseases, University of Bern, Friedbühlstrasse 51, 3010, Bern, Switzerland
| | - Lucy J Hathaway
- Institute for Infectious Diseases, University of Bern, Friedbühlstrasse 51, 3010, Bern, Switzerland
| | - Asparouh I Iliev
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012, Bern, Switzerland.
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Barbero JM, Arranz A, Rebollar Á, Culebras A, García M, Agudo R, Pérez L, Montero E. [Antipseudomonic effect of macrolides. Experience in a case of nosocomial pneumonia caused by multidrug-resistant Pseudomonas aeruginosa without response to antibiotic therapy]. REVISTA ESPANOLA DE QUIMIOTERAPIA : PUBLICACION OFICIAL DE LA SOCIEDAD ESPANOLA DE QUIMIOTERAPIA 2018; 31:72-74. [PMID: 29390604 PMCID: PMC6159352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- José Mª Barbero
- Servicio de Medicina Interna. Hospital Príncipe de Asturias. Alcalá de Henares, Madrid,Departamento de Medicina y Especialidades Médicas. Universidad de Alcalá. Alcalá de Henares, Madrid
| | - Alberto Arranz
- Servicio de Medicina Interna. Hospital Príncipe de Asturias. Alcalá de Henares, Madrid,Departamento de Medicina y Especialidades Médicas. Universidad de Alcalá. Alcalá de Henares, Madrid
| | - Ángela Rebollar
- Servicio de Medicina Interna. Hospital Príncipe de Asturias. Alcalá de Henares, Madrid
| | - Ana Culebras
- Servicio de Medicina Interna. Hospital Príncipe de Asturias. Alcalá de Henares, Madrid
| | - Marta García
- Servicio de Medicina Interna. Hospital Príncipe de Asturias. Alcalá de Henares, Madrid
| | - Rosa Agudo
- Servicio de Medicina Interna. Hospital Príncipe de Asturias. Alcalá de Henares, Madrid
| | - Laura Pérez
- Servicio de Medicina Interna. Hospital Príncipe de Asturias. Alcalá de Henares, Madrid
| | - Eduardo Montero
- Servicio de Medicina Interna. Hospital Príncipe de Asturias. Alcalá de Henares, Madrid
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Hupp S, Ribes S, Seele J, Bischoff C, Förtsch C, Maier E, Benz R, Mitchell TJ, Nau R, Iliev AI. Magnesium therapy improves outcome in Streptococcus pneumoniae meningitis by altering pneumolysin pore formation. Br J Pharmacol 2017; 174:4295-4307. [PMID: 28888095 DOI: 10.1111/bph.14027] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 08/26/2017] [Accepted: 08/29/2017] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND AND PURPOSE Streptococcus pneumoniae is the most common cause of bacterial meningitis in adults and is characterized by high lethality and substantial cognitive disabilities in survivors. Here, we have studied the capacity of an established therapeutic agent, magnesium, to improve survival in pneumococcal meningitis by modulating the neurological effects of the major pneumococcal pathogenic factor, pneumolysin. EXPERIMENTAL APPROACH We used mixed primary glial and acute brain slice cultures, pneumolysin injection in infant rats, a mouse meningitis model and complementary approaches such as Western blot, a black lipid bilayer conductance assay and live imaging of primary glial cells. KEY RESULTS Treatment with therapeutic concentrations of magnesium chloride (500 mg·kg-1 in animals and 2 mM in cultures) prevented pneumolysin-induced brain swelling and tissue remodelling both in brain slices and in animal models. In contrast to other divalent ions, which diminish the membrane binding of pneumolysin in non-therapeutic concentrations, magnesium delayed toxin-driven pore formation without affecting its membrane binding or the conductance profile of its pores. Finally, magnesium prolonged the survival and improved clinical condition of mice with pneumococcal meningitis, in the absence of antibiotic treatment. CONCLUSIONS AND IMPLICATIONS Magnesium is a well-established and safe therapeutic agent that has demonstrated capacity for attenuating pneumolysin-triggered pathogenic effects on the brain. The improved animal survival and clinical condition in the meningitis model identifies magnesium as a promising candidate for adjunctive treatment of pneumococcal meningitis, together with antibiotic therapy.
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Affiliation(s)
- Sabrina Hupp
- Institute of Anatomy, University of Bern, Bern, Switzerland.,DFG Membrane/Cytoskeleton Interaction Group, Institute of Pharmacology and Toxicology & Rudolf Virchow Center for Experimental Medicine, University of Würzburg, Würzburg, Germany
| | - Sandra Ribes
- Department of Neuropathology, University Medical Center Göttingen, Göttingen, Germany.,Department of Geriatrics, Evangelisches Krankenhaus Göttingen-Weende, Göttingen, Germany
| | - Jana Seele
- Department of Neuropathology, University Medical Center Göttingen, Göttingen, Germany.,Department of Geriatrics, Evangelisches Krankenhaus Göttingen-Weende, Göttingen, Germany
| | - Carolin Bischoff
- DFG Membrane/Cytoskeleton Interaction Group, Institute of Pharmacology and Toxicology & Rudolf Virchow Center for Experimental Medicine, University of Würzburg, Würzburg, Germany
| | - Christina Förtsch
- DFG Membrane/Cytoskeleton Interaction Group, Institute of Pharmacology and Toxicology & Rudolf Virchow Center for Experimental Medicine, University of Würzburg, Würzburg, Germany
| | - Elke Maier
- Rudolf Virchow Center for Experimental Medicine, University of Würzburg, Würzburg, Germany
| | - Roland Benz
- Rudolf Virchow Center for Experimental Medicine, University of Würzburg, Würzburg, Germany
| | - Timothy J Mitchell
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Roland Nau
- Department of Neuropathology, University Medical Center Göttingen, Göttingen, Germany.,Department of Geriatrics, Evangelisches Krankenhaus Göttingen-Weende, Göttingen, Germany
| | - Asparouh I Iliev
- Institute of Anatomy, University of Bern, Bern, Switzerland.,DFG Membrane/Cytoskeleton Interaction Group, Institute of Pharmacology and Toxicology & Rudolf Virchow Center for Experimental Medicine, University of Würzburg, Würzburg, Germany
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Brown LA, Mitchell AM, Mitchell TJ. Streptococcus pneumoniae and lytic antibiotic therapy: are we adding insult to injury during invasive pneumococcal disease and sepsis? J Med Microbiol 2017; 66:1253-1256. [PMID: 28792379 DOI: 10.1099/jmm.0.000545] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Streptococcus pneumoniae (S. pneumoniae), otherwise known as 'the pneumococcus', is a fascinating microbe that continues to pose a significant problem to public health. Currently there are no specific National Institute for Clinical Excellence (NICE) or British Thoracic Society (BTS) clinical guidelines referring to the treatment of invasive pneumococcal infection. NICE clinical guidelines suggest the use of lytic β-lactam antibiotic regimens for the management of community-acquired pneumonia and bacterial meningitis; infections for which S. pneumoniae is a likely causative organism. Lytic antibiotics have been shown to increase the release of pneumolysin (the highly inflammatory and damaging toxin of the pneumococcus), thus theoretically increasing host damage, which may lead to a decline of clinical outcomes in vulnerable patients. In light of this information, should the use of non-lytic antibiotics, such as quinolones, rifamycins and macrolides, be considered for the treatment of invasive pneumococcal disease?
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Affiliation(s)
| | - Andrea M Mitchell
- Pneumococcal Research Group, Institute of Microbiology and Infection, College of Medical and Dental Sciences, The University of Birmingham, Birmingham, UK
| | - Tim J Mitchell
- Pneumococcal Research Group, Institute of Microbiology and Infection, College of Medical and Dental Sciences, The University of Birmingham, Birmingham, UK
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Combination therapy with ampicillin and azithromycin improved outcomes in a mouse model of group B streptococcal sepsis. PLoS One 2017; 12:e0182023. [PMID: 28759625 PMCID: PMC5536305 DOI: 10.1371/journal.pone.0182023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 07/11/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Evidence suggests that β-lactam monotherapy of streptococcal infections may incite stronger inflammation and is inferior to combination therapy with macrolides. We hypothesized that use of macrolides alone or in combination with a β-lactam for group B streptococcal (GBS) sepsis would improve outcomes by reducing inflammation. METHODS TNF-α was measured from supernatants of RAW 264.7 cells stimulated with GBS isolates, in presence of four treatment regimens: ampicillin alone, azithromycin alone, or combination of azithromycin plus ampicillin. Mouse model of GBS sepsis was developed and treated with same four regimens. Clinical sepsis scores were monitored; serum cytokines (TNF-α, IL-6, IL-10) and chemokines (MIP-1α) were measured at the end. RESULTS GBS isolates exposed to azithromycin or combination (compared to ampicillin alone) stimulated less TNF production in vitro. In the murine sepsis model, mortality was lower along with decreased sepsis scores in mice treated with combination therapy. Mean serum IL-6 was lower in mice treated with azithromycin alone (66±52 pg/ml) or combination of ampicillin plus azithromycin (52±22 pg/ml) compared to ampicillin alone (260±160 pg/ml) (p<0.005). CONCLUSIONS Combination therapy of ampicillin+azithromycin improved outcomes in a murine GBS sepsis model; this therapeutic approach deserves additional study.
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Zhao X, Zhou Y, Wang G, Shi D, Zha Y, Yi P, Wang J. Morin Moderates the Biotoxicity of Pneumococcal Pneumolysin by Weakening the Oligomers' Formation. Chem Pharm Bull (Tokyo) 2017; 65:538-544. [PMID: 28566646 DOI: 10.1248/cpb.c16-00999] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Streptococcus pneumoniae (pneumococcus) is an important causative agent of acute invasive and non-invasive infections. Pneumolysin is one of a considerable number of virulence traits produced by pneumococcus that exhibits a variety of biological activities, thus making it a target of small molecule drug development. In this study, we aimed to evaluate the effect of morin, a natural compound that has no antimicrobial activity against S. pneumonia, is a potent neutralizer of pneumolysin-mediated cytotoxicity and genotoxicity by impairing oligomer formation, and possesses the capability of mitigating tissue damage caused by pneumococcus. These findings indicate that morin could be a potent candidate for a novel therapeutic or auxiliary substance to treat infections for which there are inadequate vaccines and that are resistant to traditional antibiotics.
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Affiliation(s)
- Xiaoran Zhao
- Key Laboratory of Zoonosis, Ministry of Education, College of Veterinary Medicine, Jilin University
| | - Yonglin Zhou
- Key Laboratory of Zoonosis, Ministry of Education, College of Veterinary Medicine, Jilin University
| | - Guizhen Wang
- Department of Food Quality and Safety, Jilin University
| | - Dongxue Shi
- Key Laboratory of Zoonosis, Ministry of Education, College of Veterinary Medicine, Jilin University
| | - Yonghong Zha
- Key Laboratory of Zoonosis, Ministry of Education, College of Veterinary Medicine, Jilin University
| | - Pengfei Yi
- Key Laboratory of Zoonosis, Ministry of Education, College of Veterinary Medicine, Jilin University
| | - Jianfeng Wang
- Key Laboratory of Zoonosis, Ministry of Education, College of Veterinary Medicine, Jilin University
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Role of Rifampin in Reducing Inflammation and Neuronal Damage in Childhood Bacterial Meningitis: A Pilot Randomized Controlled Trial. Pediatr Infect Dis J 2017; 36:556-559. [PMID: 28027282 DOI: 10.1097/inf.0000000000001513] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Treatment of acute bacterial meningitis in children with bactericidal antibiotics causes cell wall lysis and a surge in inflammatory cascade, which in turn contributes to neuronal damage and morbidity. Pretreatment with a nonbacteriolytic antibiotic, such as rifampin, has been shown to attenuate the inflammatory response in experimental models of bacterial meningitis. In a pilot study, in children with bacterial meningitis, we have studied markers of inflammatory response and neuronal damage in 2 groups of children with bacterial meningitis; one group received rifampin pretreatment with ceftriaxone and the other group received ceftriaxone alone. PATIENTS AND METHODS Forty children with bacterial meningitis, who were 3 months to 12 years of age, were randomly assigned to receive either a single dose rifampin (20 mg/kg) 30 minutes before ceftriaxone or ceftriaxone alone was given. The primary outcome variables were cerebrospinal fluid (CSF) concentrations of tumor necrosis factor alpha (TNFα), S100B and neuron-specific enolase on day 1 and day 5, and secondary outcome variables were the values of TNFα and interleukin 6 in serum on day 1 and day 5; hearing and neurologic sequelae at 3 months after recovery from the illness. RESULTS Children in rifampin pretreatment group had significantly lower CSF TNFα concentrations [median (interquartile range [IQR]): 15.5 (7.2-22.0) vs. 53.0 (9.0-87.5) pg/mL, P = 0.019] and S100B [median (IQR): 145.0 (54.7-450.0) vs. 447.5 (221.0-804.6) pg/mL, P = 0.033] on day 1 and S100B [median (IQR): 109.7 (64.0-287.0) vs. 322 (106.7-578.0) pg/mL, P = 0.048] and neuron-specific enolase [median (IQR): 8.6 (5-14.75) vs. 18.2 (7.0-28.75) ng/mL, P = 0.035] on day 5 when compared with ceftriaxone alone group. The rifampin-treated group also had reduced morbidity and neurologic sequelae; however, these were not statistically significant. CONCLUSIONS Pretreatment with single dose rifampin 30 minutes before ceftriaxone administration reduced the CSF concentrations of markers of inflammation and neuronal damage in children with bacterial meningitis.
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31
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Shikonin alleviates the biotoxicity produced by pneumococcal pneumolysin. Life Sci 2017; 177:1-7. [DOI: 10.1016/j.lfs.2017.04.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/31/2017] [Accepted: 04/01/2017] [Indexed: 11/19/2022]
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Anderson R, Feldman C. Pneumolysin as a potential therapeutic target in severe pneumococcal disease. J Infect 2017; 74:527-544. [PMID: 28322888 DOI: 10.1016/j.jinf.2017.03.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 03/09/2017] [Accepted: 03/11/2017] [Indexed: 12/13/2022]
Abstract
Acute pulmonary and cardiac injury remain significant causes of morbidity and mortality in those afflicted with severe pneumococcal disease, with the risk for early mortality often persisting several years beyond clinical recovery. Although remaining to be firmly established in the clinical setting, a considerable body of evidence, mostly derived from murine models of experimental infection, has implicated the pneumococcal, cholesterol-binding, pore-forming toxin, pneumolysin (Ply), in the pathogenesis of lung and myocardial dysfunction. Topics covered in this review include the burden of pneumococcal disease, risk factors, virulence determinants of the pneumococcus, complications of severe disease, antibiotic and adjuvant therapies, as well as the structure of Ply and the role of the toxin in disease pathogenesis. Given the increasing recognition of the clinical potential of Ply-neutralisation strategies, the remaining sections of the review are focused on updates of the types, benefits and limitations of currently available therapies which may attenuate, directly and/or indirectly, the injurious actions of Ply. These include recently described experimental therapies such as various phytochemicals and lipids, and a second group of more conventional agents the members of which remain the subject of ongoing clinical evaluation. This latter group, which is covered more extensively, encompasses macrolides, statins, corticosteroids, and platelet-targeted therapies, particularly aspirin.
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Affiliation(s)
- Ronald Anderson
- Department of Immunology and Institute of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa.
| | - Charles Feldman
- Division of Pulmonology, Department of Internal Medicine, Charlotte Maxeke Johannesburg Academic Hospital and Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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33
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Maurer J, Hupp S, Bischoff C, Foertsch C, Mitchell TJ, Chakraborty T, Iliev AI. Distinct Neurotoxicity Profile of Listeriolysin O from Listeria monocytogenes. Toxins (Basel) 2017; 9:toxins9010034. [PMID: 28098781 PMCID: PMC5308266 DOI: 10.3390/toxins9010034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 01/09/2017] [Accepted: 01/10/2017] [Indexed: 11/16/2022] Open
Abstract
Cholesterol-dependent cytolysins (CDCs) are protein toxins that originate from Gram-positive bacteria and contribute substantially to their pathogenicity. CDCs bind membrane cholesterol and build prepores and lytic pores. Some effects of the toxins are observed in non-lytic concentrations. Two pathogens, Streptococcus pneumoniae and Listeria monocytogenes, cause fatal bacterial meningitis, and both produce toxins of the CDC family-pneumolysin and listeriolysin O, respectively. It has been demonstrated that pneumolysin produces dendritic varicosities (dendrite swellings) and dendritic spine collapse in the mouse neocortex, followed by synaptic loss and astrocyte cell shape remodeling without elevated cell death. We utilized primary glial cultures and acute mouse brain slices to examine the neuropathological effects of listeriolysin O and to compare it to pneumolysin with identical hemolytic activity. In cultures, listeriolysin O permeabilized cells slower than pneumolysin did but still initiated non-lytic astrocytic cell shape changes, just as pneumolysin did. In an acute brain slice culture system, listeriolysin O produced dendritic varicosities in an NMDA-dependent manner but failed to cause dendritic spine collapse and cortical astrocyte reorganization. Thus, listeriolysin O demonstrated slower cell permeabilization and milder glial cell remodeling ability than did pneumolysin and lacked dendritic spine collapse capacity but exhibited equivalent dendritic pathology.
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Affiliation(s)
- Jana Maurer
- DFG Membrane/Cytoskeleton Interaction Group, Institute of Pharmacology and Toxicology & Rudolf Virchow Center for Experimental Biomedical Science, University of Würzburg, Versbacherstr. 9, 97078 Würzburg, Germany.
- Institute of Physiology and Pathophysiology, Heidelberg University, Im Neuenheimer Feld 326, 69120 Heidelberg, Germany.
| | - Sabrina Hupp
- DFG Membrane/Cytoskeleton Interaction Group, Institute of Pharmacology and Toxicology & Rudolf Virchow Center for Experimental Biomedical Science, University of Würzburg, Versbacherstr. 9, 97078 Würzburg, Germany.
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012 Bern, Switzerland.
| | - Carolin Bischoff
- DFG Membrane/Cytoskeleton Interaction Group, Institute of Pharmacology and Toxicology & Rudolf Virchow Center for Experimental Biomedical Science, University of Würzburg, Versbacherstr. 9, 97078 Würzburg, Germany.
| | - Christina Foertsch
- DFG Membrane/Cytoskeleton Interaction Group, Institute of Pharmacology and Toxicology & Rudolf Virchow Center for Experimental Biomedical Science, University of Würzburg, Versbacherstr. 9, 97078 Würzburg, Germany.
| | - Timothy J Mitchell
- Chair of Microbial Infection and Immunity, Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
| | - Trinad Chakraborty
- Institute for Medical Microbiology, University of Giessen, Schubertstr. 81, 35392 Giessen, Germany.
| | - Asparouh I Iliev
- DFG Membrane/Cytoskeleton Interaction Group, Institute of Pharmacology and Toxicology & Rudolf Virchow Center for Experimental Biomedical Science, University of Würzburg, Versbacherstr. 9, 97078 Würzburg, Germany.
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012 Bern, Switzerland.
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Rai P, He F, Kwang J, Engelward BP, Chow VTK. Pneumococcal Pneumolysin Induces DNA Damage and Cell Cycle Arrest. Sci Rep 2016; 6:22972. [PMID: 27026501 PMCID: PMC4812240 DOI: 10.1038/srep22972] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 02/22/2016] [Indexed: 01/24/2023] Open
Abstract
Streptococcus pneumoniae produces pneumolysin toxin as a key virulence factor against host cells. Pneumolysin is a cholesterol-dependent cytolysin (CDC) toxin that forms lytic pores in host membranes and mediates pneumococcal disease pathogenesis by modulating inflammatory responses. Here, we show that pneumolysin, which is released during bacterial lysis, induces DNA double strand breaks (DSBs), as indicated by ataxia telangiectasia mutated (ATM)-mediated H2AX phosphorylation (γH2AX). Pneumolysin-induced γH2AX foci recruit mediator of DNA damage checkpoint 1 (MDC1) and p53 binding protein 1 (53BP1), to sites of DSBs. Importantly, results show that toxin-induced DNA damage precedes cell cycle arrest and causes apoptosis when DNA-dependent protein kinase (DNA-PK)-mediated non-homologous end joining is inhibited. Further, we observe that cells that were undergoing DNA replication harbored DSBs in greater frequency during pneumolysin treatment. This observation raises the possibility that DSBs might be arising as a result of replication fork breakdown. Additionally, neutralizing the oligomerization domain of pneumolysin with monoclonal antibody suppresses DNA damage and also cell cycle arrest, indicating that pneumolysin oligomerization is important for causing DNA damage. Taken together, this study reveals a previously unidentified ability of pneumolysin to induce cytotoxicity via DNA damage, with implications in the pathophysiology of S. pneumoniae infection.
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Affiliation(s)
- Prashant Rai
- Infectious Diseases Group, Singapore-MIT Alliance for Research &Technology, Singapore 138602.,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545
| | - Fang He
- Animal Health Biotechnology, Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604
| | - Jimmy Kwang
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545.,Animal Health Biotechnology, Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604
| | - Bevin P Engelward
- Infectious Diseases Group, Singapore-MIT Alliance for Research &Technology, Singapore 138602.,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Vincent T K Chow
- Infectious Diseases Group, Singapore-MIT Alliance for Research &Technology, Singapore 138602.,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545
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Nel JG, Theron AJ, Durandt C, Tintinger GR, Pool R, Mitchell TJ, Feldman C, Anderson R. Pneumolysin activates neutrophil extracellular trap formation. Clin Exp Immunol 2016; 184:358-67. [PMID: 26749379 DOI: 10.1111/cei.12766] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 12/14/2015] [Accepted: 12/23/2015] [Indexed: 02/06/2023] Open
Abstract
The primary objective of the current study was to investigate the potential of the pneumococcal toxin, pneumolysin (Ply), to activate neutrophil extracellular trap (NET) formation in vitro. Isolated human blood neutrophils were exposed to recombinant Ply (5-20 ng ml(-1) ) for 30-90 min at 37°C and NET formation measured using the following procedures to detect extracellular DNA: (i) flow cytometry using Vybrant® DyeCycle™ Ruby; (ii) spectrofluorimetry using the fluorophore, Sytox(®) Orange (5 μM); and (iii) NanoDrop(®) technology. These procedures were complemented by fluorescence microscopy using 4', 6-diamino-2-phenylindole (DAPI) (nuclear stain) in combination with anti-citrullinated histone monoclonal antibodies to visualize nets. Exposure of neutrophils to Ply resulted in relatively rapid (detected within 30-60 min), statistically significant (P < 0·05) dose- and time-related increases in the release of cellular DNA impregnated with both citrullinated histone and myeloperoxidase. Microscopy revealed that NETosis appeared to be restricted to a subpopulation of neutrophils, the numbers of NET-forming cells in the control and Ply-treated systems (10 and 20 ng ml(-1) ) were 4·3 (4·2), 14.3 (9·9) and 16·5 (7·5), respectively (n = 4, P < 0·0001 for comparison of the control with both Ply-treated systems). Ply-induced NETosis occurred in the setting of retention of cell viability, and apparent lack of involvement of reactive oxygen species and Toll-like receptor 4. In conclusion, Ply induces vital NETosis in human neutrophils, a process which may either contribute to host defence or worsen disease severity, depending on the intensity of the inflammatory response during pneumococcal infection.
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Affiliation(s)
| | - A J Theron
- Department of Immunology, Faculty of Health Sciences, University of Pretoria and Tshwane Academic Division of the National Health Laboratory Service.,South African Medical Research Council Unit for Stem Cell Research, Institute for Cellular and Molecular Medicine, Department of Immunology, Faculty of Health Sciences, University of Pretoria
| | - C Durandt
- South African Medical Research Council Unit for Stem Cell Research, Institute for Cellular and Molecular Medicine, Department of Immunology, Faculty of Health Sciences, University of Pretoria
| | - G R Tintinger
- Department of Internal Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - R Pool
- Department of Haematology
| | - T J Mitchell
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - C Feldman
- Division of Pulmonology, Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg and Charlotte Maxeke Academic Hospital, Johannesburg, South Africa
| | - R Anderson
- South African Medical Research Council Unit for Stem Cell Research, Institute for Cellular and Molecular Medicine, Department of Immunology, Faculty of Health Sciences, University of Pretoria
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36
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Microscale insights into pneumococcal antibiotic mutant selection windows. Nat Commun 2015; 6:8773. [PMID: 26514094 PMCID: PMC4632196 DOI: 10.1038/ncomms9773] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 09/30/2015] [Indexed: 11/26/2022] Open
Abstract
The human pathogen Streptococcus pneumoniae shows alarming rates of antibiotic resistance emergence. The basic requirements for de novo resistance emergence are poorly understood in the pneumococcus. Here we systematically analyse the impact of antibiotics on S. pneumoniae at concentrations that inhibit wild type cells, that is, within the mutant selection window. We identify discrete growth-inhibition profiles for bacteriostatic and bactericidal compounds, providing a predictive framework for distinction between the two classifications. Cells treated with bacteriostatic agents show continued gene expression activity, and real-time mutation assays link this activity to the development of genotypic resistance. Time-lapse microscopy reveals that antibiotic-susceptible pneumococci display remarkable growth and death bistability patterns in response to many antibiotics. We furthermore capture the rise of subpopulations with decreased susceptibility towards cell wall synthesis inhibitors (heteroresisters). We show that this phenomenon is epigenetically inherited, and that heteroresistance potentiates the accumulation of genotypic resistance. The emergence of antibiotic resistance in bacteria is driven by inhibitory but non-lethal antibiotic concentrations. Here, Sorg and Veening study the effects of different antibiotics on the pneumococcus, with a focus on inhibition dynamics, metabolic activity and processes at the single-cell level.
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Disentangling competence for genetic transformation and virulence in Streptococcus pneumoniae. Curr Genet 2015; 62:97-103. [PMID: 26403231 DOI: 10.1007/s00294-015-0520-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 09/10/2015] [Accepted: 09/11/2015] [Indexed: 10/23/2022]
Abstract
Horizontal gene transfer mediated by the competence regulon is a major driver of genome plasticity in Streptococcus pneumoniae. When pneumococcal cells enter the competent state, about 6% of the genes in the genome are up-regulated. Among these, some genes are essential for genetic transformation while others are dispensable for the process. Exhaustive deletion analyses show that some up-regulated genes dispensable for genetic transformation contribute to pneumococcal-mediated pneumonia and bacteremia infections. Interestingly, virulence functions of such genes are either dependent or independent of the competent state. Among the competent-state-dependent genes are those mediating allolysis, a process where small fraction of non-competent cells within the pneumococcal population are lysed by their competent counterparts, releasing DNA presumably for transformation. Inadvertently, the pore-forming toxin pneumolysin is also released during allolysis, contributing to virulence. In this review, we discuss recent advances in our understanding of pneumococcal virulence processes mediated by the competence regulon. We proposed that coupling of competence induction and bacterial fitness drives the natural selection to favor an intact competence regulon, which in turn, provides the long-term benefits of genetic plasticity.
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Rifampin use in acute community-acquired meningitis in intensive care units: the French retrospective cohort ACAM-ICU study. Crit Care 2015; 19:303. [PMID: 26306393 PMCID: PMC4549935 DOI: 10.1186/s13054-015-1021-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 08/04/2015] [Indexed: 11/29/2022] Open
Abstract
Introduction Bacterial meningitis among critically ill adult patients remains associated with both high mortality and frequent, persistent disability. Vancomycin was added to treatment with a third-generation cephalosporin as recommended by French national guidelines. Because animal model studies had suggested interest in the use of rifampin for treatment of bacterial meningitis, and after the introduction of early corticosteroid therapy (in 2002), there was a trend toward increasing rifampin use for intensive care unit (ICU) patients. The aim of this article is to report on this practice. Methods Five ICUs participated in the study. Baseline characteristics and treatment data were retrospectively collected from charts of patients admitted with a diagnosis of acute bacterial meningitis during a 5-year period (2004–2008). The ICU mortality was the main outcome measure; Glasgow Outcome Scale and 3-month mortality were also assessed. Results One hundred fifty-seven patients were included. Streptococcus pneumoniae and Neisseria meningitidis were the most prevalent causative microorganisms. The ICU mortality rate was 15 %. High doses of a cephalosporin were the most prevalent initial antimicrobial treatment. The delay between admission and administration of the first antibiotic dose was correlated with ICU mortality. Rifampin was used with a cephalosporin for 32 patients (ranging from 8 % of the cohort for 2004 to 30 % in 2008). Administration of rifampin within the first 24 h of hospitalization could be associated with a lower ICU survival. Statistical association between such an early rifampin treatment and ICU mortality reached significance only for patients with pneumococcal meningitis (p=0.031) in univariate analysis, but not in the logistic model. Conclusions We report on the role of rifampin use for patients with community-acquired meningitis, and the results of this study suggest that this practice may be associated with lower mortality in the ICU. Nevertheless, the only independent predictors of ICU mortality were organ failure and pneumococcal infection. Further studies are required to confirm these results and to explain how rifampin use would reduce mortality. Electronic supplementary material The online version of this article (doi:10.1186/s13054-015-1021-7) contains supplementary material, which is available to authorized users.
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Nau R, Djukic M, Spreer A, Ribes S, Eiffert H. Bacterial meningitis: an update of new treatment options. Expert Rev Anti Infect Ther 2015; 13:1401-23. [DOI: 10.1586/14787210.2015.1077700] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Alhamdi Y, Neill DR, Abrams ST, Malak HA, Yahya R, Barrett-Jolley R, Wang G, Kadioglu A, Toh CH. Circulating Pneumolysin Is a Potent Inducer of Cardiac Injury during Pneumococcal Infection. PLoS Pathog 2015; 11:e1004836. [PMID: 25973949 PMCID: PMC4431880 DOI: 10.1371/journal.ppat.1004836] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 03/26/2015] [Indexed: 11/19/2022] Open
Abstract
Streptococcus pneumoniae accounts for more deaths worldwide than any other single pathogen through diverse disease manifestations including pneumonia, sepsis and meningitis. Life-threatening acute cardiac complications are more common in pneumococcal infection compared to other bacterial infections. Distinctively, these arise despite effective antibiotic therapy. Here, we describe a novel mechanism of myocardial injury, which is triggered and sustained by circulating pneumolysin (PLY). Using a mouse model of invasive pneumococcal disease (IPD), we demonstrate that wild type PLY-expressing pneumococci but not PLY-deficient mutants induced elevation of circulating cardiac troponins (cTns), well-recognized biomarkers of cardiac injury. Furthermore, elevated cTn levels linearly correlated with pneumococcal blood counts (r=0.688, p=0.001) and levels were significantly higher in non-surviving than in surviving mice. These cTn levels were significantly reduced by administration of PLY-sequestering liposomes. Intravenous injection of purified PLY, but not a non-pore forming mutant (PdB), induced substantial increase in cardiac troponins to suggest that the pore-forming activity of circulating PLY is essential for myocardial injury in vivo. Purified PLY and PLY-expressing pneumococci also caused myocardial inflammatory changes but apoptosis was not detected. Exposure of cultured cardiomyocytes to PLY-expressing pneumococci caused dose-dependent cardiomyocyte contractile dysfunction and death, which was exacerbated by further PLY release following antibiotic treatment. We found that high PLY doses induced extensive cardiomyocyte lysis, but more interestingly, sub-lytic PLY concentrations triggered profound calcium influx and overload with subsequent membrane depolarization and progressive reduction in intracellular calcium transient amplitude, a key determinant of contractile force. This was coupled to activation of signalling pathways commonly associated with cardiac dysfunction in clinical and experimental sepsis and ultimately resulted in depressed cardiomyocyte contractile performance along with rhythm disturbance. Our study proposes a detailed molecular mechanism of pneumococcal toxin-induced cardiac injury and highlights the major translational potential of targeting circulating PLY to protect against cardiac complications during pneumococcal infections.
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Affiliation(s)
- Yasir Alhamdi
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Daniel R. Neill
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Simon T. Abrams
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Hesham A. Malak
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Reham Yahya
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Richard Barrett-Jolley
- Department of Musculoskeletal Biology, Institute of Aging and Chronic Diseases, University of Liverpool, Liverpool, United Kingdom
| | - Guozheng Wang
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Aras Kadioglu
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Cheng-Hock Toh
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
- Roald Dahl Haemostasis & Thrombosis Centre, Royal Liverpool University Hospital, Liverpool, United Kingdom
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Engineered liposomes sequester bacterial exotoxins and protect from severe invasive infections in mice. Nat Biotechnol 2014; 33:81-8. [PMID: 25362245 DOI: 10.1038/nbt.3037] [Citation(s) in RCA: 156] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 09/09/2014] [Indexed: 12/25/2022]
Abstract
Gram-positive bacterial pathogens that secrete cytotoxic pore-forming toxins, such as Staphylococcus aureus and Streptococcus pneumoniae, cause a substantial burden of disease. Inspired by the principles that govern natural toxin-host interactions, we have engineered artificial liposomes that are tailored to effectively compete with host cells for toxin binding. Liposome-bound toxins are unable to lyse mammalian cells in vitro. We use these artificial liposomes as decoy targets to sequester bacterial toxins that are produced during active infection in vivo. Administration of artificial liposomes within 10 h after infection rescues mice from septicemia caused by S. aureus and S. pneumoniae, whereas untreated mice die within 24-33 h. Furthermore, liposomes protect mice against invasive pneumococcal pneumonia. Composed exclusively of naturally occurring lipids, tailored liposomes are not bactericidal and could be used therapeutically either alone or in conjunction with antibiotics to combat bacterial infections and to minimize toxin-induced tissue damage that occurs during bacterial clearance.
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Nau R, Ribes S, Djukic M, Eiffert H. Strategies to increase the activity of microglia as efficient protectors of the brain against infections. Front Cell Neurosci 2014; 8:138. [PMID: 24904283 PMCID: PMC4033068 DOI: 10.3389/fncel.2014.00138] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 05/30/2014] [Indexed: 12/24/2022] Open
Abstract
In healthy individuals, infections of the central nervous system (CNS) are comparatively rare. Based on the ability of microglial cells to phagocytose and kill pathogens and on clinical findings in immunocompromised patients with CNS infections, we hypothesize that an intact microglial function is crucial to protect the brain from infections. Phagocytosis of pathogens by microglial cells can be stimulated by agonists of receptors of the innate immune system. Enhancing this pathway to increase the resistance of the brain to infections entails the risk of inducing collateral damage to the nervous tissue. The diversity of microglial cells opens avenue to selectively stimulate sub-populations responsible for the defence against pathogens without stimulating sub-populations which are responsible for collateral damage to the nervous tissue. Palmitoylethanolamide (PEA), an endogenous lipid, increased phagocytosis of bacteria by microglial cells in vitro without a measurable proinflammatory effect. It was tested clinically apparently without severe side effects. Glatiramer acetate increased phagocytosis of latex beads by microglia and monocytes, and dimethyl fumarate enhanced elimination of human immunodeficiency virus from infected macrophages without inducing a release of proinflammatory compounds. Therefore, the discovery of compounds which stimulate the elimination of pathogens without collateral damage of neuronal structures appears an achievable goal. PEA and, with limitations, glatiramer acetate and dimethyl fumarate appear promising candidates.
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Affiliation(s)
- Roland Nau
- Department of Neuropathology, University Medical Centre Göttingen Göttingen, Germany ; Department of Geriatrics, Evangelisches Krankenhaus Göttingen-Weende Göttingen, Germany
| | - Sandra Ribes
- Department of Neuropathology, University Medical Centre Göttingen Göttingen, Germany
| | - Marija Djukic
- Department of Neuropathology, University Medical Centre Göttingen Göttingen, Germany ; Department of Geriatrics, Evangelisches Krankenhaus Göttingen-Weende Göttingen, Germany
| | - Helmut Eiffert
- Department of Clinical Microbiology, University Medical Centre Göttingen Göttingen, Germany
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Imperi F, Leoni L, Visca P. Antivirulence activity of azithromycin in Pseudomonas aeruginosa. Front Microbiol 2014; 5:178. [PMID: 24795709 PMCID: PMC4001013 DOI: 10.3389/fmicb.2014.00178] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 03/31/2014] [Indexed: 11/13/2022] Open
Abstract
Antibiotics represent our bulwark to combat bacterial infections, but the spread of antibiotic resistance compromises their clinical efficacy. Alternatives to conventional antibiotics are urgently needed in order to complement the existing antibacterial arsenal. The macrolide antibiotic azithromycin (AZM) provides a paradigmatic example of an "unconventional" antibacterial drug. Besides its growth-inhibiting activity, AZM displays potent anti-inflammatory properties, as well as antivirulence activity on some intrinsically resistant bacteria, such as Pseudomonas aeruginosa. In this bacterium, the antivirulence activity of AZM mainly relies on its ability to interact with the ribosome, resulting in direct and/or indirect repression of specific subsets of genes involved in virulence, quorum sensing, biofilm formation, and intrinsic antibiotic resistance. Both clinical experience and clinical trials have shown the efficacy of AZM in the treatment of chronic pulmonary infections caused by P. aeruginosa. The aim of this review is to combine results from laboratory studies with evidence from clinical trials in order to unify the information on the in vivo mode of action of AZM in P. aeruginosa infection.
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Affiliation(s)
- Francesco Imperi
- Pasteur Institute-Cenci Bolognetti Foundation and Department of Biology and Biotechnology “C. Darwin”, “Sapienza” University of RomeRome, Italy
| | - Livia Leoni
- Department of Sciences, “Roma Tre” UniversityRome, Italy
| | - Paolo Visca
- Department of Sciences, “Roma Tre” UniversityRome, Italy
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McIntosh EDG. Treatment and prevention strategies to combat pediatric pneumococcal meningitis. Expert Rev Anti Infect Ther 2014; 3:739-50. [PMID: 16207165 DOI: 10.1586/14787210.3.5.739] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Pneumococcal meningitis is a severe, life-threatening infection of the nervous system affecting infants, children and adults alike. The incidence of pneumococcal meningitis in infants and children less than 2 years of age in Europe is approximately 10 out of 100,000 per year, rising to approximately 148 out of 100,000 per year in Gambian infants. The use of highly sensitive tests such as PCR may increase the likelihood of detecting the infection by 20% or more. Epidemics of serotype 1 pneumococcal meningitis in northern Ghana, have had many of the characteristics of meningococcal meningitis epidemics. Neurologic sequelae may occur in 28-63% of cases, and serotype 3 is associated with a 2.54 relative risk of death. The pathogenic process can be divided into invasion, inflammatory pathways, bacterial toxicity and damage; pneumolysin being particularly associated with apoptosis. In the future, neuroprotection may be achieved, targeting this process at all these levels. Therapeutic guidelines have been published by the Infectious Diseases Society of America. Standard empiric therapy, in those aged greater than or equal to 1 month, is a third-generation cephalosporin plus vancomycin. There is insufficient evidence relating to the use or otherwise of corticosteroids in pneumococcal meningitis to make a firm recommendation. The advent of a pneumococcal conjugate vaccine is the most powerful tool available for the prevention of pneumococcal meningitis in all parts of the world.
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Ferrand J, Ferrero RL. Recognition of Extracellular Bacteria by NLRs and Its Role in the Development of Adaptive Immunity. Front Immunol 2013; 4:344. [PMID: 24155747 PMCID: PMC3801148 DOI: 10.3389/fimmu.2013.00344] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 10/07/2013] [Indexed: 01/21/2023] Open
Abstract
Innate immune recognition of bacteria is the first requirement for mounting an effective immune response able to control infection. Over the previous decade, the general paradigm was that extracellular bacteria were only sensed by cell surface-expressed Toll-like receptors (TLRs), whereas cytoplasmic sensors, including members of the Nod-like receptor (NLR) family, were specific to pathogens capable of breaching the host cell membrane. It has become apparent, however, that intracellular innate immune molecules, such as the NLRs, play key roles in the sensing of not only intracellular, but also extracellular bacterial pathogens or their components. In this review, we will discuss the various mechanisms used by bacteria to activate NLR signaling in host cells. These mechanisms include bacterial secretion systems, pore-forming toxins, and outer membrane vesicles. We will then focus on the influence of NLR activation on the development of adaptive immune responses in different cell types.
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Affiliation(s)
- Jonathan Ferrand
- Centre for Innate Immunity and Infectious Diseases, Monash Institute of Medical Research, Monash University , Clayton, VIC , Australia
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Nau R, Djukic M, Spreer A, Eiffert H. Bacterial meningitis: new therapeutic approaches. Expert Rev Anti Infect Ther 2013; 11:1079-95. [PMID: 24073921 DOI: 10.1586/14787210.2013.839381] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Bacterial meningitis remains a disease with high mortality and long-term morbidity. Outcome critically depends on the rapid initiation of effective antibiotic therapy. Since a further increase of the incidence of pathogens resistant to antibacterials can be expected both in community-acquired and nosocomial bacterial meningitis, the choice of an optimum initial empirical antibiotic regimen will gain significance. In this context, the use of antibiotics which are bactericidal but do not lyse bacteria, may emerge as a therapeutic option. Conversely, the role of corticosteroids, which decrease the entry of hydrophilic antibacterials into the cerebrospinal fluid, as adjunctive therapy will probably decline as a consequence of the increasing antibiotic resistance of bacteria causing meningitis. Consequent vaccination of all children at present is the most efficient manner to reduce disease burden.
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Affiliation(s)
- Roland Nau
- Department of Geriatrics, Evangelisches Krankenhaus Göttingen-Weende, An der Lutter 24, 37075 Göttingen, Germany
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Los FCO, Randis TM, Aroian RV, Ratner AJ. Role of pore-forming toxins in bacterial infectious diseases. Microbiol Mol Biol Rev 2013; 77:173-207. [PMID: 23699254 PMCID: PMC3668673 DOI: 10.1128/mmbr.00052-12] [Citation(s) in RCA: 299] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Pore-forming toxins (PFTs) are the most common bacterial cytotoxic proteins and are required for virulence in a large number of important pathogens, including Streptococcus pneumoniae, group A and B streptococci, Staphylococcus aureus, Escherichia coli, and Mycobacterium tuberculosis. PFTs generally disrupt host cell membranes, but they can have additional effects independent of pore formation. Substantial effort has been devoted to understanding the molecular mechanisms underlying the functions of certain model PFTs. Likewise, specific host pathways mediating survival and immune responses in the face of toxin-mediated cellular damage have been delineated. However, less is known about the overall functions of PFTs during infection in vivo. This review focuses on common themes in the area of PFT biology, with an emphasis on studies addressing the roles of PFTs in in vivo and ex vivo models of colonization or infection. Common functions of PFTs include disruption of epithelial barrier function and evasion of host immune responses, which contribute to bacterial growth and spreading. The widespread nature of PFTs make this group of toxins an attractive target for the development of new virulence-targeted therapies that may have broad activity against human pathogens.
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Affiliation(s)
| | - Tara M. Randis
- Department of Pediatrics, Columbia University, New York, New York, USA
| | - Raffi V. Aroian
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, California, USA
| | - Adam J. Ratner
- Department of Pediatrics, Columbia University, New York, New York, USA
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Tillotson GS, Zinner SH. Paul Ehrlich, a prescient pioneer in the field of antimicrobial chemotherapy: what did he foresee a century ago? Expert Rev Anti Infect Ther 2013; 11:113-5. [DOI: 10.1586/eri.12.166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Steel HC, Theron AJ, Cockeran R, Anderson R, Feldman C. Pathogen- and host-directed anti-inflammatory activities of macrolide antibiotics. Mediators Inflamm 2012; 2012:584262. [PMID: 22778497 PMCID: PMC3388425 DOI: 10.1155/2012/584262] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 03/02/2012] [Indexed: 12/27/2022] Open
Abstract
Macrolide antibiotics possess several, beneficial, secondary properties which complement their primary antimicrobial activity. In addition to high levels of tissue penetration, which may counteract seemingly macrolide-resistant bacterial pathogens, these agents also possess anti-inflammatory properties, unrelated to their primary antimicrobial activity. Macrolides target cells of both the innate and adaptive immune systems, as well as structural cells, and are beneficial in controlling harmful inflammatory responses during acute and chronic bacterial infection. These secondary anti-inflammatory activities of macrolides appear to be particularly effective in attenuating neutrophil-mediated inflammation. This, in turn, may contribute to the usefulness of these agents in the treatment of acute and chronic inflammatory disorders of both microbial and nonmicrobial origin, predominantly of the airways. This paper is focused on the various mechanisms of macrolide-mediated anti-inflammatory activity which target both microbial pathogens and the cells of the innate and adaptive immune systems, with emphasis on their clinical relevance.
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Affiliation(s)
- Helen C Steel
- Medical Research Council Unit for Inflammation and Immunity, Department of Immunology, Faculty of Health Sciences, University of Pretoria and Tshwane Academic Division of the National Health Laboratory Service, P.O. Box 2034, Pretoria 0001, South Africa.
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Wall EC, Gordon SB, Hussain S, Goonetilleke URS, Gritzfeld J, Scarborough M, Kadioglu A. Persistence of pneumolysin in the cerebrospinal fluid of patients with pneumococcal meningitis is associated with mortality. Clin Infect Dis 2012; 54:701-5. [PMID: 22238165 PMCID: PMC3275762 DOI: 10.1093/cid/cir926] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Poor prognosis in Pneumococcal meningitis may be associated with high pneumolysin levels in cerebrospinal fluid (CSF). In patient samples we showed that pneumolysin levels in CSF remained high after 48 hours in nonsurvivors of meningitis compared with survivors. Selective antipneumolysin treatment may present a novel therapeutic option.
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Affiliation(s)
- Emma C Wall
- Clinical Research Group, Liverpool School of Tropical Medicine, United Kingdom
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