1
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Xu S, Tan S, Romanos P, Reedy JL, Zhang Y, Mansour MK, Vyas JM, Mecsas J, Mou H, Leong JM. Blocking HXA 3-mediated neutrophil elastase release during S. pneumoniae lung infection limits pulmonary epithelial barrier disruption and bacteremia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.25.600637. [PMID: 38979170 PMCID: PMC11230237 DOI: 10.1101/2024.06.25.600637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Streptococcus pneumoniae (Sp), a leading cause of community-acquired pneumonia, can spread from the lung into the bloodstream to cause septicemia and meningitis, with a concomitant three-fold increase in mortality. Limitations in vaccine efficacy and a rise in antimicrobial resistance have spurred searches for host-directed therapies that target pathogenic immune processes. Polymorphonuclear leukocytes (PMNs) are essential for infection control but can also promote tissue damage and pathogen spread. The major Sp virulence factor, pneumolysin (PLY), triggers acute inflammation by stimulating the 12-lipoxygenase (12-LOX) eicosanoid synthesis pathway in epithelial cells. This pathway is required for systemic spread in a mouse pneumonia model and produces a number of bioactive lipids, including hepoxilin A3 (HXA3), a hydroxy epoxide PMN chemoattractant that has been hypothesized to facilitate breach of mucosal barriers. To understand how 12-LOX-dependent inflammation promotes dissemination during Sp lung infection and dissemination, we utilized bronchial stem cell-derived air-liquid interface (ALI) cultures that lack this enzyme to show that HXA3 methyl ester (HXA3-ME) is sufficient to promote basolateral-to-apical PMN transmigration, monolayer disruption, and concomitant Sp barrier breach. In contrast, PMN transmigration in response to the non-eicosanoid chemoattractant fMLP did not lead to epithelial disruption or bacterial translocation. Correspondingly, HXA3-ME but not fMLP increased release of neutrophil elastase (NE) from Sp-infected PMNs. Pharmacologic blockade of NE secretion or activity diminished epithelial barrier disruption and bacteremia after pulmonary challenge of mice. Thus, HXA3 promotes barrier disrupting PMN transmigration and NE release, pathological events that can be targeted to curtail systemic disease following pneumococcal pneumonia.
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Affiliation(s)
- Shuying Xu
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA
- Graduate Program in Immunology, Tufts Graduate School of Biomedical Sciences, Boston, MA
| | - Shumin Tan
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA
| | - Patricia Romanos
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA
- Francisco de Vitoria University, Madrid, Spain
| | - Jennifer L. Reedy
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA
| | - Yihan Zhang
- Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Boston, MA
| | - Michael K. Mansour
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA
| | - Jatin M. Vyas
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA
| | - Joan Mecsas
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA
| | - Hongmei Mou
- Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Boston, MA
| | - John M. Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA
- Stuart B Levy Center for the Integrated Management of Antimicrobial Resistance, Tufts University, Boston, MA
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2
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Wang J, Hu L, Zhang Z, Sui C, Zhu X, Wu C, Zhang L, Lv M, Yang W, Zhou D, Shang Z. Mice fatal pneumonia model induced by less-virulent Streptococcus pneumoniae via intratracheal aerosolization. Future Microbiol 2024:1-16. [PMID: 38913747 DOI: 10.1080/17460913.2024.2355738] [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: 12/18/2023] [Accepted: 05/10/2024] [Indexed: 06/26/2024] Open
Abstract
Aim: Animal models of fatal pneumonia caused by Streptococcus pneumoniae (Spn) have not been reliably generated using many strains of less virulent serotypes. Materials & methods: Pulmonary infection of a less virulent Spn serotype1 strain in the immunocompetent mice was established via the intratracheal aerosolization (ITA) route. The survival, local and systemic bacterial spread, pathological changes and inflammatory responses of this model were compared with those of mice challenged via the intratracheal instillation, intranasal instillation and intraperitoneal injection routes. Results: ITA and intratracheal instillation both induced fatal pneumonia; however, ITA resulted in better lung bacterial deposition and distribution, pathological homogeneity and delivery efficiency. Conclusion: ITA is an optimal route for developing animal models of severe pulmonary infections.
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Affiliation(s)
- Jiazhen Wang
- Department of Immunology of Basic Medical College, Guizhou Medical University, Guian New Area, 561113, China
- State Key Laboratory of Pathogen & Biosecurity, Beijing Institute of Microbiology & Epidemiology, Academy of Military Medical Sciences, Beijing, 100071, China
| | - Lingfei Hu
- State Key Laboratory of Pathogen & Biosecurity, Beijing Institute of Microbiology & Epidemiology, Academy of Military Medical Sciences, Beijing, 100071, China
| | - Zhijun Zhang
- State Key Laboratory of Pathogen & Biosecurity, Beijing Institute of Microbiology & Epidemiology, Academy of Military Medical Sciences, Beijing, 100071, China
| | - Chengyu Sui
- State Key Laboratory of Pathogen & Biosecurity, Beijing Institute of Microbiology & Epidemiology, Academy of Military Medical Sciences, Beijing, 100071, China
- Department of Microbiology of Basic Medical College, Anhui Medical University, Hefei, 230032, China
| | - Xiaoyu Zhu
- State Key Laboratory of Pathogen & Biosecurity, Beijing Institute of Microbiology & Epidemiology, Academy of Military Medical Sciences, Beijing, 100071, China
| | - Chengxi Wu
- State Key Laboratory of Pathogen & Biosecurity, Beijing Institute of Microbiology & Epidemiology, Academy of Military Medical Sciences, Beijing, 100071, China
| | - Lili Zhang
- State Key Laboratory of Pathogen & Biosecurity, Beijing Institute of Microbiology & Epidemiology, Academy of Military Medical Sciences, Beijing, 100071, China
| | - Meng Lv
- State Key Laboratory of Pathogen & Biosecurity, Beijing Institute of Microbiology & Epidemiology, Academy of Military Medical Sciences, Beijing, 100071, China
| | - Wenhui Yang
- State Key Laboratory of Pathogen & Biosecurity, Beijing Institute of Microbiology & Epidemiology, Academy of Military Medical Sciences, Beijing, 100071, China
| | - Dongsheng Zhou
- State Key Laboratory of Pathogen & Biosecurity, Beijing Institute of Microbiology & Epidemiology, Academy of Military Medical Sciences, Beijing, 100071, China
| | - Zhengling Shang
- Department of Immunology of Basic Medical College, Guizhou Medical University, Guian New Area, 561113, China
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3
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Yesilkaya H, Oggioni MR, Andrew PW. Streptococcus pneumoniae: 'captain of the men of death' and financial burden. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 36748691 DOI: 10.1099/mic.0.001275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Streptococcus pneumoniae may inhabit the upper respiratory tract of humans without causing harm but it also causes diseases with high morbidity and mortality. It has excellent adaptive capabilities thanks to its ability to shuffle its genetic content by acquiring and incorporating DNA from other bacteria and is highly competent for genetic transformation. Sugar sensing, cleavage and transport ensure its fitness and survival in the host, and intracellular survival in macrophages has been linked to virulence. The polysaccharide capsule and toxin pneumolysin are the most important virulence determinants. Polysaccharide-based vaccines provide protection against the serotypes represented in vaccine formulations.
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Affiliation(s)
- Hasan Yesilkaya
- Department of Respiratory Sciences, University of Leicester, Leicester LE1 7RH, UK
| | - Marco R Oggioni
- Department of Genetics, University of Leicester, Leicester LE1 7RH, UK.,Dipartimento di Farmacia e Biotecnologie, University of Bologna, Bologna, Italy
| | - Peter W Andrew
- Department of Respiratory Sciences, University of Leicester, Leicester LE1 7RH, UK
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4
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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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5
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Hypervirulent pneumococcal serotype 1 harbours two pneumolysin variants with differential haemolytic activity. Sci Rep 2020; 10:17313. [PMID: 33057054 PMCID: PMC7560715 DOI: 10.1038/s41598-020-73454-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 09/14/2020] [Indexed: 12/13/2022] Open
Abstract
Streptococcus pneumoniae is a devastating global pathogen. Prevalent in sub-Saharan Africa, pneumococcal serotype 1 is atypical in that it is rarely found as a nasopharyngeal coloniser, yet is described as one of the most common causes of invasive pneumococcal disease. Clonal sequence type (ST)-306 and ST615 are representative of the two major serotype 1 lineages A and C, respectively. Here we investigated the virulence properties and haemolytic activities of these 2 clonal types using in vivo mouse models and in vitro assays. A lethal dose of ST615 administered intranasally to mice led to the rapid onset of disease symptoms and resulted in 90% mortality. In contrast, mice exposed to the same infection dose of ST306 or a pneumolysin (Ply)-deficient ST615 failed to develop any disease symptoms. Interestingly, the 2 strains did not differ in their ability to bind the immune complement or to undergo neutrophil-mediated phagocytosis. Upon comparative genomic analysis, we found higher within-ST sequence diversity in ST615 compared with ST306 and determined that ZmpA, ZmpD proteins, and IgA protease, were uniquely found in ST615. Using cell fractionation and cell contact-dependent assay, we made the unexpected finding that ST615 harbours the expression of two haemolytic variants of Ply: a cell-wall restricted fully haemolytic Ply, and a cytosolic pool of Ply void of any detectable haemolytic activity. This is the first time such a phenomenon has been described. We discuss the biological significance of our observation in relation to the aptitude of the pneumococcus for sustaining its human reservoir.
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6
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Qi Z, Guo Y, Zhang H, Yu Q, Zhang P. Betulin attenuates pneumolysin-induced cell injury and DNA damage. J Appl Microbiol 2020; 130:843-851. [PMID: 32621771 DOI: 10.1111/jam.14769] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 06/23/2020] [Accepted: 06/29/2020] [Indexed: 12/19/2022]
Abstract
AIMS Pneumolysin, a pore-forming toxin, is an important virulence factor of Streptococcus pneumoniae with multiple biological activity, such as cell lysis and DNA damage. Thus, targeting this toxin is alternative strategy for the treatment of S. pneumoniae infection. METHODS AND RESULTS Haemolysin assay was performed to identify the potential PLY inhibitor. The mechanism by which betulin, a natural compound from birch bark, against PLY was determined via MICs determination, western blot analysis and oligomerization analysis. Cytotoxicity and Immunofluorescence assays were further used to evaluate the protection of betulin against PLY-induced cell injury and DNA damage. Here, betulin, a natural compound from birch bark, was indentified as an effective inhibitor of PLY. Importantly, at the concentrations required for such inhibition, betulin has no influence on S. pneumoniae viability or PLY production. The interaction of betulin with PLY restrict the olgomerizaiton of this toxin and, thus, directly neutralizing the activity of PLY. Additionally, betulin treatment alleviate PLY induced cells injury and DNA damage in the co-culture system of PLY and A549 cells. CONCLUSIONS Betulin could be used as a promising leading compound against S. pneumoniae virulence by directly targeting PLY without antibacterial activity. SIGNIFICANCE AND IMPACT OF THE STUDY The results presented in this work provided a novel strategy and candidate for S. pneumoniae infection.
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Affiliation(s)
- Z Qi
- Department of Thoracic Surgery, the First Hospital of Jilin University, Changchun, Jilin, China.,Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, Jilin, China
| | - Y Guo
- Department of Thoracic Surgery, the First Hospital of Jilin University, Changchun, Jilin, China.,Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, Jilin, China
| | - H Zhang
- Department of Thoracic Surgery, the First Hospital of Jilin University, Changchun, Jilin, China.,Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, Jilin, China
| | - Q Yu
- Jilin Provincial Animal Disease Control Center, Changchun, China
| | - P Zhang
- Department of Thoracic Surgery, the First Hospital of Jilin University, Changchun, Jilin, China
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7
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Interaction of Macrophages and Cholesterol-Dependent Cytolysins: The Impact on Immune Response and Cellular Survival. Toxins (Basel) 2020; 12:toxins12090531. [PMID: 32825096 PMCID: PMC7551085 DOI: 10.3390/toxins12090531] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/13/2020] [Accepted: 08/15/2020] [Indexed: 02/07/2023] Open
Abstract
Cholesterol-dependent cytolysins (CDCs) are key virulence factors involved in many lethal bacterial infections, including pneumonia, necrotizing soft tissue infections, bacterial meningitis, and miscarriage. Host responses to these diseases involve myeloid cells, especially macrophages. Macrophages use several systems to detect and respond to cholesterol-dependent cytolysins, including membrane repair, mitogen-activated protein (MAP) kinase signaling, phagocytosis, cytokine production, and activation of the adaptive immune system. However, CDCs also promote immune evasion by silencing and/or destroying myeloid cells. While there are many common themes between the various CDCs, each CDC also possesses specific features to optimally benefit the pathogen producing it. This review highlights host responses to CDC pathogenesis with a focus on macrophages. Due to their robust plasticity, macrophages play key roles in the outcome of bacterial infections. Understanding the unique features and differences within the common theme of CDCs bolsters new tools for research and therapy.
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8
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Adams W, Bhowmick R, Bou Ghanem EN, Wade K, Shchepetov M, Weiser JN, McCormick BA, Tweten RK, Leong JM. Pneumolysin Induces 12-Lipoxygenase-Dependent Neutrophil Migration during Streptococcus pneumoniae Infection. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2020; 204:101-111. [PMID: 31776202 PMCID: PMC7195902 DOI: 10.4049/jimmunol.1800748] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 10/16/2019] [Indexed: 12/23/2022]
Abstract
Streptococcus pneumoniae is a major cause of pneumonia, wherein infection of respiratory mucosa drives a robust influx of neutrophils. We have previously shown that S. pneumoniae infection of the respiratory epithelium induces the production of the 12-lipoxygenase (12-LOX)-dependent lipid inflammatory mediator hepoxilin A3, which promotes recruitment of neutrophils into the airways, tissue damage, and lethal septicemia. Pneumolysin (PLY), a member of the cholesterol-dependent cytolysin (CDC) family, is a major S. pneumoniae virulence factor that generates ∼25-nm diameter pores in eukaryotic membranes and promotes acute inflammation, tissue damage, and bacteremia. We show that a PLY-deficient S. pneumoniae mutant was impaired in triggering human neutrophil transepithelial migration in vitro. Ectopic production of PLY endowed the nonpathogenic Bacillus subtilis with the ability to trigger neutrophil recruitment across human-cultured monolayers. Purified PLY, several other CDC family members, and the α-toxin of Clostridium septicum, which generates pores with cross-sectional areas nearly 300 times smaller than CDCs, reproduced this robust neutrophil transmigration. PLY non-pore-forming point mutants that are trapped at various stages of pore assembly did not recruit neutrophils. PLY triggered neutrophil recruitment in a 12-LOX-dependent manner in vitro. Instillation of wild-type PLY but not inactive derivatives into the lungs of mice induced robust 12-LOX-dependent neutrophil migration into the airways, although residual inflammation induced by PLY in 12-LOX-deficient mice indicates that 12-LOX-independent pathways also contribute to PLY-triggered pulmonary inflammation. These data indicate that PLY is an important factor in promoting hepoxilin A3-dependent neutrophil recruitment across pulmonary epithelium in a pore-dependent fashion.
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Affiliation(s)
- Walter Adams
- Department of Molecular Biology and Microbiology, Tufts University, Boston, MA 02111
- Department of Biological Sciences, San Jose State University, San Jose, CA 95192
| | - Rudra Bhowmick
- Department of Molecular Biology and Microbiology, Tufts University, Boston, MA 02111
| | - Elsa N Bou Ghanem
- Department of Molecular Biology and Microbiology, Tufts University, Boston, MA 02111
| | - Kristin Wade
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
| | - Mikhail Shchepetov
- Department of Microbiology, University of Pennsylvania, Philadelphia, PA 19104
| | - Jeffrey N Weiser
- Department of Microbiology, New York University School of Medicine, New York, NY 10016; and
| | - Beth A McCormick
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01655
| | - Rodney K Tweten
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
| | - John M Leong
- Department of Molecular Biology and Microbiology, Tufts University, Boston, MA 02111;
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9
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Effect of decreased BCAA synthesis through disruption of ilvC gene on the virulence of Streptococcus pneumoniae. Arch Pharm Res 2017; 40:921-932. [PMID: 28735462 DOI: 10.1007/s12272-017-0931-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 07/17/2017] [Indexed: 10/19/2022]
Abstract
Streptococcus pneumoniae (pneumococcus) is responsible for significant morbidity and mortality worldwide. It causes a variety of life-threatening infections such as pneumonia, bacteremia, and meningitis. In bacterial physiology, the metabolic pathway of branched-chain amino acids (BCAAs) plays an important role in virulence. Nonetheless, the function of IlvC, one of the enzymes involved in the biosynthesis of BCAAs, in S. pneumoniae remains unclear. Here, we demonstrated that downregulation of BCAA biosynthesis by ilvC ablation can diminish BCAA concentration and expression of pneumolysin (Ply) and LytA, and subsequently attenuate virulence. Infection with an ilvC mutant showed significantly reduced mortality and colonization in comparison with strain D39 (serotype 2, wild type), suggesting that ilvC can potentiate S. pneumoniae virulence due to adequate BCAA synthesis. Taken together, these results suggest that the function of ilvC in BCAA synthesis is essential for virulence factor and could play an important role in the pathogenesis of respiratory infections.
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10
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Andre GO, Converso TR, Politano WR, Ferraz LFC, Ribeiro ML, Leite LCC, Darrieux M. Role of Streptococcus pneumoniae Proteins in Evasion of Complement-Mediated Immunity. Front Microbiol 2017; 8:224. [PMID: 28265264 PMCID: PMC5316553 DOI: 10.3389/fmicb.2017.00224] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 01/31/2017] [Indexed: 12/14/2022] Open
Abstract
The complement system plays a central role in immune defense against Streptococcus pneumoniae. In order to evade complement attack, pneumococci have evolved a number of mechanisms that limit complement mediated opsonization and subsequent phagocytosis. This review focuses on the strategies employed by pneumococci to circumvent complement mediated immunity, both in vitro and in vivo. At last, since many of the proteins involved in interactions with complement components are vaccine candidates in different stages of validation, we explore the use of these antigens alone or in combination, as potential vaccine approaches that aim at elimination or drastic reduction in the ability of this bacterium to evade complement.
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Affiliation(s)
- Greiciely O Andre
- Laboratório de Biologia Celular e Molecular de Microrganismos, Universidade São Francisco Bragança Paulista, Brazil
| | - Thiago R Converso
- Centro de Biotecnologia, Instituto ButantanSão Paulo, Brazil; Programa de Pós-graduação Interunidades em Biotecnologia, Universidade de São PauloSão Paulo, Brazil
| | - Walter R Politano
- Laboratório de Biologia Celular e Molecular de Microrganismos, Universidade São Francisco Bragança Paulista, Brazil
| | - Lucio F C Ferraz
- Laboratório de Biologia Celular e Molecular de Microrganismos, Universidade São Francisco Bragança Paulista, Brazil
| | - Marcelo L Ribeiro
- Laboratório de Farmacologia, Universidade São Francisco Bragança Paulista, Brazil
| | | | - Michelle Darrieux
- Laboratório de Biologia Celular e Molecular de Microrganismos, Universidade São Francisco Bragança Paulista, Brazil
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11
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Mochan-Keef E, Swigon D, Ermentrout GB, Clermont G. A Three-Tiered Study of Differences in Murine Intrahost Immune Response to Multiple Pneumococcal Strains. PLoS One 2015; 10:e0134012. [PMID: 26244863 PMCID: PMC4526468 DOI: 10.1371/journal.pone.0134012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 07/03/2015] [Indexed: 11/18/2022] Open
Abstract
We apply a previously developed 4-variable ordinary differential equation model of in-host immune response to pneumococcal pneumonia to study the variability of the immune response of MF1 mice and to explore bacteria-driven differences in disease progression and outcome. In particular, we study the immune response to D39 strain of bacteria missing portions of the pneumolysin protein controlling either the hemolytic activity or complement-activating activity, the response to D39 bacteria deficient in either neuraminidase A or B, and the differences in the response to D39 (serotype 2), 0100993 (serotype 3), and TIGR4 (serotype 4) bacteria. The model accurately reproduces infection kinetics in all cases and provides information about which mechanisms in the immune response have the greatest effect in each case. Results suggest that differences in the ability of bacteria to defeat immune response are primarily due to the ability of the bacteria to elude nonspecific clearance in the lung tissue as well as the ability to create damage to the lung epithelium.
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Affiliation(s)
- Ericka Mochan-Keef
- Joint Carnegie Mellon University-University of Pittsburgh PhD Program in Computational Biology, Pittsburgh, PA, United States of America
- * E-mail:
| | - David Swigon
- Department of Mathematics, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - G. Bard Ermentrout
- Department of Mathematics, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Gilles Clermont
- Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America
- McGowan Institute for Regenerative Medicine, Center for Inflammation and Regenerative Modeling, University of Pittsburgh, Pittsburgh, PA, United States of America
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12
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Sun T, Hou H, Lu J, Xu M, Gu T, Wang D, Dong Y, Jiang C, Kong W, Wu Y. Detection and comparison of structure and function of wild-type pneumolysin and its novel mutant PlyM2. Chem Res Chin Univ 2015. [DOI: 10.1007/s40242-015-5105-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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13
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Cole J, Aberdein J, Jubrail J, Dockrell DH. The role of macrophages in the innate immune response to Streptococcus pneumoniae and Staphylococcus aureus: mechanisms and contrasts. Adv Microb Physiol 2014; 65:125-202. [PMID: 25476766 DOI: 10.1016/bs.ampbs.2014.08.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Macrophages are critical mediators of innate immune responses against bacteria. The Gram-positive bacteria Streptococcus pneumoniae and Staphylococcus aureus express a range of virulence factors, which challenge macrophages' immune competence. We review how macrophages respond to this challenge. Macrophages employ a range of strategies to phagocytose and kill each pathogen. When the macrophages capacity to clear bacteria is overwhelmed macrophages play important roles in orchestrating the inflammatory response through pattern recognition receptor-mediated responses. Macrophages also ensure the inflammatory response is tightly constrained, to avoid tissue damage, and play an important role in downregulating the inflammatory response once initial bacterial replication is controlled.
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Affiliation(s)
- Joby Cole
- Department of Infection and Immunity, University of Sheffield Medical School and Sheffield Teaching Hospitals, Sheffield, United Kingdom
| | - Jody Aberdein
- Department of Infection and Immunity, University of Sheffield Medical School and Sheffield Teaching Hospitals, Sheffield, United Kingdom
| | - Jamil Jubrail
- Department of Infection and Immunity, University of Sheffield Medical School and Sheffield Teaching Hospitals, Sheffield, United Kingdom
| | - David H Dockrell
- Department of Infection and Immunity, University of Sheffield Medical School and Sheffield Teaching Hospitals, Sheffield, United Kingdom.
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14
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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: 298] [Impact Index Per Article: 27.1] [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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Neill DR, Smeaton S, Bangert M, Kadioglu A. Nasopharyngeal carriage with Streptococcus pneumoniae augments the immunizing effect of pneumolysin toxoid B. J Allergy Clin Immunol 2012; 131:1433-5.e1. [PMID: 23260752 DOI: 10.1016/j.jaci.2012.11.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 10/17/2012] [Accepted: 11/05/2012] [Indexed: 11/18/2022]
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Hupp S, Förtsch C, Wippel C, Ma J, Mitchell TJ, Iliev AI. Direct transmembrane interaction between actin and the pore-competent, cholesterol-dependent cytolysin pneumolysin. J Mol Biol 2012; 425:636-46. [PMID: 23219469 PMCID: PMC3659287 DOI: 10.1016/j.jmb.2012.11.034] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 11/19/2012] [Accepted: 11/23/2012] [Indexed: 12/02/2022]
Abstract
The eukaryotic actin cytoskeleton is an evolutionarily well-established pathogen target, as a large number of bacterial factors disturb its dynamics to alter the function of the host cells. These pathogenic factors modulate or mimic actin effector proteins or they modify actin directly, leading to an imbalance of the precisely regulated actin turnover. Here, we show that the pore-forming, cholesterol-dependent cytolysin pneumolysin (PLY), a major neurotoxin of Streptococcus pneumoniae, has the capacity to bind actin directly and to enhance actin polymerisation in vitro. In cells, the toxin co-localised with F-actin shortly after exposure, and this direct interaction was verified by Förster resonance energy transfer. PLY was capable of exerting its effect on actin through the lipid bilayer of giant unilamellar vesicles, but only when its pore competence was preserved. The dissociation constant of G-actin binding to PLY in a biochemical environment was 170–190 nM, which is indicative of a high-affinity interaction, comparable to the affinity of other intracellular actin-binding factors. Our results demonstrate the first example of a direct interaction of a pore-forming toxin with cytoskeletal components, suggesting that the cross talk between pore-forming cytolysins and cells is more complex than previously thought.
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Affiliation(s)
- Sabrina Hupp
- DFG Membrane/Cytoskeleton Interaction Group, Institute of Pharmacology and Toxicology & Rudolf Virchow Centre for Experimental Biomedical Science, University of Würzburg, Versbacherstr. 9, 97078 Würzburg, Germany
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17
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Kamtchoua T, Bologa M, Hopfer R, Neveu D, Hu B, Sheng X, Corde N, Pouzet C, Zimmermann G, Gurunathan S. Safety and immunogenicity of the pneumococcal pneumolysin derivative PlyD1 in a single-antigen protein vaccine candidate in adults. Vaccine 2012; 31:327-33. [PMID: 23153437 DOI: 10.1016/j.vaccine.2012.11.005] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 10/24/2012] [Accepted: 11/04/2012] [Indexed: 10/27/2022]
Abstract
BACKGROUND Pneumococcal vaccines based on conserved protein antigens have the potential to offer expanded protection against Streptococcus pneumoniae. OBJECTIVE This study examined the safety and immunogenicity in adults of three doses of a pneumococcal single-antigen protein vaccine candidate formulated with aluminum hydroxide adjuvant and recombinantly derived, highly detoxified, genetically mutated pneumolysin protein (PlyD1). METHODS This phase I, randomized, placebo-controlled, observer-blinded, dose-escalating study enrolled adults (18-50 years). In a pilot safety study, participants received a single injection of 10 μg PlyD1 and were observed for 24 h. Following review of the pilot safety data, participants were randomized (2:1) to receive two injections of PlyD1 at one of three doses or placebo 30 days apart. Assignment of second injection and successive dose cohorts was made after blinded safety reviews after each injection at each dose level. Safety endpoints included rates of solicited injection site reactions, solicited systemic reactions, unsolicited adverse events (AEs), serious AEs (SAEs), and safety laboratory tests. Immunogenicity endpoints included geometric mean concentrations of anti-PlyD1 IgG as determined by ELISA and functional assessment in an in vitro toxin neutralization assay. RESULTS The study included a total of 100 participants, including 10 in the pilot study and 90 in the randomized study. None of the participants in the pilot study had SAEs, allergic reactions, or other safety concerns. Ninety participants received two doses of or placebo (n=30) or active vaccine candidate at 10 (n=20), 25 (n=20), or 50 μg (n=20). No vaccine-related SAE or discontinuation due to an AE occurred. Most solicited reactions were mild and transient. The most frequently reported solicited reactions were pain at the injection site and myalgia. Antigen-specific IgG levels and functional activity showed dose-related increases. When comparing the three dose levels, a plateau effect was observed at the 25 μg dose. CONCLUSIONS All dose levels were safe and immunogenic. Repeat vaccination significantly increased the level of anti-PlyD1 antibodies. Functional antibody activity was demonstrated in sera from vaccinated individuals (ClinicalTrials.gov no. NCT01444352).
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Affiliation(s)
- Thierry Kamtchoua
- Covance Clinical Research Unit AG, SPC 327-10, Lettenweg 118, CH-4123 Allschwil, Switzerland.
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Hoegen T, Tremel N, Klein M, Angele B, Wagner H, Kirschning C, Pfister HW, Fontana A, Hammerschmidt S, Koedel U. The NLRP3 inflammasome contributes to brain injury in pneumococcal meningitis and is activated through ATP-dependent lysosomal cathepsin B release. THE JOURNAL OF IMMUNOLOGY 2011; 187:5440-51. [PMID: 22003197 DOI: 10.4049/jimmunol.1100790] [Citation(s) in RCA: 164] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Streptococcus pneumoniae meningitis causes brain damage through inflammation-related pathways whose identity and mechanisms of action are yet unclear. We previously identified caspase-1, which activates precursor IL-1 type cytokines, as a central mediator of inflammation in pneumococcal meningitis. In this study, we demonstrate that lack of the inflammasome components ASC or NLRP3 that are centrally involved in caspase-1 activation decreases scores of clinical and histological disease severity as well as brain inflammation in murine pneumococcal meningitis. Using specific inhibitors (anakinra and rIL-18-binding protein), we further show that ASC- and NLRP3-dependent pathologic alterations are solely related to secretion of both IL-1β and IL-18. Moreover, using differentiated human THP-1 cells, we demonstrate that the pneumococcal pore-forming toxin pneumolysin is a key inducer of IL-1β expression and inflammasome activation upon pneumococcal challenge. The latter depends on the release of ATP, lysosomal destabilization (but not disruption), and cathepsin B activation. The in vivo importance of this pathway is supported by our observation that the lack of pneumolysin and cathepsin B inhibition is associated with a better clinical course and less brain inflammation in murine pneumococcal meningitis. Collectively, our study indicates a central role of the NLRP3 inflammasome in the pathology of pneumococcal meningitis. Thus, interference with inflammasome activation might be a promising target for adjunctive therapy of this disease.
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Affiliation(s)
- Tobias Hoegen
- Department of Neurology, Clinic of the University of Munich, D-81377 Munich, Germany
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Pneumolysin with low hemolytic activity confers an early growth advantage to Streptococcus pneumoniae in the blood. Infect Immun 2011; 79:4122-30. [PMID: 21788389 DOI: 10.1128/iai.05418-11] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus pneumoniae is a leading cause of human diseases such as pneumonia, bacteremia, meningitis, and otitis media. Pneumolysin (Ply) is an important virulence factor of S. pneumoniae and a promising future vaccine target. However, the expansion of clones carrying ply alleles with reduced hemolytic activity has been observed in serotypes associated with outbreaks of invasive disease and includes an allele identified in a highly virulent serotype 1 isolate (ply4496). The virulence of Ply-deficient and ply allelic-replacement derivatives of S. pneumoniae D39 was compared with that of wild-type D39. In addition, the protective immunogenicity of Ply against pneumococci with low versus high hemolytic activity was also investigated. Replacement of D39 ply with ply4496 resulted in a small but statistically significant reduction of virulence. However, both native Ply- and Ply4496-expressing strains were significantly more virulent than a Ply-deficient mutant. While the numbers of both Ply- and Ply4496-expressing isolate cells were higher in the blood than the numbers of Ply-deficient mutant cells, the growth of the Ply4496-expressing strain was superior to that of the wild type in the first 15 h postchallenge. Ply immunization provided protection regardless of the hemolytic activity of the challenge strain. In summary, we show that low-hemolytic-activity Ply alleles contribute to systemic virulence and may provide a survival advantage in the blood. Moreover, pneumococci expressing such alleles remain vulnerable to Ply-based vaccines.
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Sanders ME, Norcross EW, Moore QC, Onwubiko C, King LB, Fratkin J, Marquart ME. A comparison of pneumolysin activity and concentration in vitro and in vivo in a rabbit endophthalmitis model. Clin Ophthalmol 2011; 2:793-800. [PMID: 19668433 PMCID: PMC2699808 DOI: 10.2147/opth.s3941] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The purpose of this study was to determine whether the in vitro activity and concentration of Streptococcus pneumoniae pneumolysin correlated to the pathogenesis of S. pneumoniae endophthalmitis. Five S. pneumoniae clinical endophthalmitis strains were grown in media to similar optical densities (OD), and extracellular milieu was tested for pneumolysin activity by hemolysis of rabbit red blood cells. Pneumolysin concentration was determined using a sandwich ELISA. Rabbit vitreous was injected with 102 colony-forming units (CFU) of 1 of 2 different strains with low hemolytic activity (n = 10 and 12 for strains 4 and 5, respectively) or 1 of 3 different strains with high hemolytic activity (n = 12 per strain). Pathogenesis of endophthalmitis infection was graded by slit lamp examination (SLE) at 24 hours post-infection. Bacteria were recovered from infected vitreous and quantitated. The SLE scores of eyes infected with strains having high hemolytic activity were significantly higher than the scores of those infected with strains having low hemolytic activity (P < 0.05). Pneumolysin concentration in vitro, however, did not correlate with hemolysis or severity of endophthalmitis. Bacterial concentrations from the vitreous infected with 4 of the strains were not significantly different (P > 0.05). These data suggest that pneumolysin hemolytic activity in vitro directly correlates to the pathogenesis of S. pneumoniae endophthalmitis. The protein concentration of pneumolysin, however, is not a reliable indicator of pneumolysin activity.
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Prise en charge des pneumonies graves à pneumocoque — Pneumonies communautaires aiguës sévères à Streptococcus pneumoniae (PAC Sp): rôle de l’hôte et des facteurs de virulence bactérienne. MEDECINE INTENSIVE REANIMATION 2011. [DOI: 10.1007/s13546-010-0128-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Norcross EW, Tullos NA, Taylor SD, Sanders ME, Marquart ME. Assessment of Streptococcus pneumoniae capsule in conjunctivitis and keratitis in vivo neuraminidase activity increases in nonencapsulated pneumococci following conjunctival infection. Curr Eye Res 2010; 35:787-98. [PMID: 20795860 DOI: 10.3109/02713683.2010.492462] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
PURPOSE The pneumococcal capsule is required for pathogenesis in systemic infections, yet reports show most conjunctivitis outbreaks are caused by nonencapsulated pneumococci, while keratitis infections are caused by encapsulated strains. This study aims to determine the effect of capsule in pneumococcal keratitis and conjunctivitis in rabbit models of infection. METHODS A capsule-deficient isogenic mutant was created using homologous transformation. Parent and mutant strains were injected within the upper bulbar conjunctiva (conjunctivitis) or into the corneal stroma (keratitis) of New Zealand white rabbits. Clinical examinations were performed 24 and 48 hr post-infection at which time corneas or conjunctivae were removed, homogenized, and plated to determine the recovered bacterial load. Whole eyes were removed for histological examination. The neuraminidase activity was determined following in vitro and in vivo growth. RESULTS There were no significant differences in clinical scores between the eyes infected with the parent or mutant for either infection, nor was there a difference in the amount of bacteria recovered from the cornea. In the conjunctivae, however, the mutant strain was cleared by the host faster than the parent strain. Histological examination showed slightly more infiltrating polymorphonuclear leukocytes (PMN) and macrophages in the conjunctivae infected with the parent strain. The neuraminidase activity of both strains was not significantly different when the strains were grown in vitro. However, the neuraminidase activity of the parent was significantly less than that of the mutant at 3 and 12 hr post conjunctival infection. CONCLUSIONS Although more outbreaks of pneumococcal conjunctivitis are tied to nonencapsulated S. pneumoniae strains, this study showed that an encapsulated strain was capable of establishing conjunctivitis in a rabbit injection model and survive attack by the host immune system longer than its nonencapsulated isogenic mutant. Nonetheless, the nonencapsulated pneumococci had an increased neuraminidase activity level in vivo when compared to the parent strain.
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Affiliation(s)
- Erin W Norcross
- Department of Microbiology, University of Mississippi Medical Center, Jackson, Mississippi 39216, USA
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Sanders ME, Norcross EW, Moore QC, Fratkin J, Thompson H, Marquart ME. Immunization with pneumolysin protects against both retinal and global damage caused by Streptococcus pneumoniae endophthalmitis. J Ocul Pharmacol Ther 2010; 26:571-7. [PMID: 21034245 DOI: 10.1089/jop.2010.0077] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PURPOSE To determine whether immunization with pneumolysin (PLY) protects against pneumococcal endophthalmitis. METHODS New Zealand white rabbits were immunized with a mutant form of PLY that retains only 1% of its cytolytic activity until serum IgG titers were ≥51,200. For a negative control, rabbits were immunized with phosphate-buffered saline (mock). Each vitreous was injected with 10(2) colony-forming units of a clinical endophthalmitis isolate of Streptococcus pneumoniae. Severity of endophthalmitis was graded by slit lamp examination at 24 and 48 h postinfection (PI). Serial dilutions of vitreous were plated for bacterial colony-forming units quantitation, eyes were extracted for histology, and a whole blood survival assay was performed. RESULTS Immunized rabbits had a significantly lower mean slit lamp examination score at 24 and 48 h PI when compared to mock immunized rabbits (P ≤ 0.002). There was not a significant difference in bacterial load in the vitreous at 24 or 48 h PI. Histological sections showed that retinas of mock immunized rabbits appeared to be destroyed, whereas those of PLY immunized rabbits remained largely intact. Damage spread to the aqueous humor, stroma, and conjunctiva of mock immunized rabbits by 48 h PI. Minimal damage was observed in the vitreous of PLY immunized rabbits and did not spread to other parts of the eye. Whole blood from immunized rabbits inhibited the growth of bacteria better than whole blood from mock immunized rabbits. CONCLUSION Immunization with PLY helps protect the eye from damage caused by pneumococcal endophthalmitis.
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Affiliation(s)
- Melissa E Sanders
- Department of Microbiology, University of Mississippi Medical Center, Jackson, MS 39216, USA
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Detection of large numbers of pneumococcal virulence genes in streptococci of the mitis group. J Clin Microbiol 2010; 48:2762-9. [PMID: 20519466 DOI: 10.1128/jcm.01746-09] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Seven streptococcal isolates from the mitis group were analyzed for the presence of pneumococcal gene homologues by comparative genomic hybridization studies with microarrays based on open reading frames from the genomes of Streptococcus pneumoniae TIGR4 and R6. The diversity of pneumolysin (ply) and neuraminidase A (nanA) gene sequences was explored in more detail in a collection of 14 S. pseudopneumoniae and 29 mitis group isolates, respectively. The mitis group isolates used in the microarray experiments included a type strain (NCTC 12261), two S. mitis isolates from the nasopharynxes of children, one S. mitis isolate from a case of infective endocarditis, one S. mitis isolate from a dental abscess, and one S. oralis isolate and one S. pseudopneumoniae isolate from the nasopharynxes of children. The results of the microarray study showed that the 5 S. mitis isolates had homologues to between 67 and 82% of pneumococcal virulence genes, S. oralis hybridized to 83% of pneumococcal virulence genes, and S. pseudopneumoniae hybridized to 92% of identified pneumococcal virulence genes. Comparison of the pneumolysin, mitilysin (mly), and newly identified pseudopneumolysin (pply) gene sequences revealed that mly and pply genes are more closely related to each other than either is to ply. In contrast, the nanA gene sequences in the pneumococcus and streptococci from the mitis group are closely clustered together, sharing 99.4 to 99.7% sequence identity with pneumococcal nanA alleles.
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Abstract
Bacterial meningitis is still an important infectious disease with a high morbidity and mortality rate. Bacterial infection of the cerebrospinal fluid (CSF) space causes a powerful inflammatory reaction that is largely responsibly for meningitis-induced tissue damage and adverse outcome of the disease. In a landmark series of experiments in the mid-1980s, cell wall components including lipooligosaccharides and lipoteichoic acid were indicated to be the key bacterial elements that can trigger the host inflammatory response in the CSF. Ten years ago, the discovery of Toll-like receptor proteins (TLRs) that allow the detection of microbial components and initiate the host immune response opened up new horizons in research on the pathophysiology of meningitis. Cell culture approaches provided the first evidence for a crucial role of TLRs in sensing meningeal pathogens including Streptococcus pneumoniae, Neisseria meningitidis, Streptococcus agalactiae, and Listeria monocytogenes. Subsequently, studies in mice with single or combined deficiencies in TLRs demonstrated that TLR activation is a key event in meningeal inflammation and, even more interestingly, a pivotal factor for meningitis-associated tissue damage. A detailed understanding of the mechanisms of host-pathogen interactions in the CSF space may generate new opportunities for specific treatment strategies for bacterial meningitis.
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Abstract
SUMMARY Streptococcus pneumoniae is a colonizer of human nasopharynx, but it is also an important pathogen responsible for high morbidity, high mortality, numerous disabilities, and high health costs throughout the world. Major diseases caused by S. pneumoniae are otitis media, pneumonia, sepsis, and meningitis. Despite the availability of antibiotics and vaccines, pneumococcal infections still have high mortality rates, especially in risk groups. For this reason, there is an exceptionally extensive research effort worldwide to better understand the diseases caused by the pneumococcus, with the aim of developing improved therapeutics and vaccines. Animal experimentation is an essential tool to study the pathogenesis of infectious diseases and test novel drugs and vaccines. This article reviews both historical and innovative laboratory pneumococcal animal models that have vastly added to knowledge of (i) mechanisms of infection, pathogenesis, and immunity; (ii) efficacies of antimicrobials; and (iii) screening of vaccine candidates. A comprehensive description of the techniques applied to induce disease is provided, the advantages and limitations of mouse, rat, and rabbit models used to mimic pneumonia, sepsis, and meningitis are discussed, and a section on otitis media models is also included. The choice of appropriate animal models for in vivo studies is a key element for improved understanding of pneumococcal disease.
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Preston JA, Dockrell DH. Virulence factors in pneumococcal respiratory pathogenesis. Future Microbiol 2008; 3:205-21. [PMID: 18366340 DOI: 10.2217/17460913.3.2.205] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Streptococcus pneumoniae (the pneumococcus) is a major global cause of human disease. Since the publication of the entire sequence of TIGR4 in 2001, our understanding of this human pathogen has increased significantly. Genetic studies, and the use of mutant strains have refined our understanding of the pathogenic mechanisms of classic pneumococcal virulence factors, including the polysaccharide capsule, pneumolysin and surface-expressed proteins. Genetic screens are identifying novel virulence factors. Characterization of pili and bacteriocins, as well as genes associated with competence, metabolism and resistance to oxidative stress has provided new insights into the genetic diversity of the pneumococcus. Further appreciation of the molecular basis of pneumococcal pathogenesis will lead to more effective strategies for the prevention and management of pneumococcal disease.
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Affiliation(s)
- Julie A Preston
- Section of Infection, Inflammation & Immunity, L-Floor, University of Sheffield School of Medicine & Biomedical Sciences, Royal Hallamshire Hospital, Glossop Road, Sheffield S10 2JF, UK.
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Pneumolysin released during Streptococcus pneumoniae autolysis is a potent activator of intracellular oxygen radical production in neutrophils. Infect Immun 2008; 76:4079-87. [PMID: 18559434 DOI: 10.1128/iai.01747-07] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus pneumoniae is a major cause of otitis media, pneumonia, meningitis, and septicemia in humans. The host defense against this pathogen largely depends on bacterial killing by neutrophils. A peculiar property of pneumococci is their tendency to undergo autolysis, i.e., autoinduced disruption of the bacterial cell wall mediated by activation of the enzyme LytA, under stationary growth conditions. LytA is a virulence factor, but the molecular background for this has not been fully clarified. Here we examine how bacterial compounds released upon autolysis affect the production of reactive oxygen species (ROS) in neutrophils. We found that the S. pneumoniae strains A17 and D39 induced activation of the NADPH oxidase and the production of ROS in human neutrophils and that this activation was blocked when LytA was inactivated. The ROS-inducing bacterial substance released from autolyzed bacteria was identified as the cytoplasmic toxin pneumolysin. Further screening of clinical pneumococcal strains of various sero- and genotypes revealed that selected strains expressing toxins with reduced pneumolysin-dependent hemolytic activity had decreased abilities to induce ROS in neutrophils. Furthermore, a mutated form of purified pneumolysin lacking hemolytic and complement binding functions (PdT) did not induce any oxygen radical production. The ROS produced in response to pneumolysin formed mainly intracellularly, which may explain why this production was not detected previously. ROS released intracellularly may function as signaling molecules, modifying the function of neutrophils in bacterial defense.
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Kadioglu A, Weiser JN, Paton JC, Andrew PW. The role of Streptococcus pneumoniae virulence factors in host respiratory colonization and disease. Nat Rev Microbiol 2008; 6:288-301. [PMID: 18340341 DOI: 10.1038/nrmicro1871] [Citation(s) in RCA: 800] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Streptococcus pneumoniae is a Gram-positive bacterial pathogen that colonizes the mucosal surfaces of the host nasopharynx and upper airway. Through a combination of virulence-factor activity and an ability to evade the early components of the host immune response, this organism can spread from the upper respiratory tract to the sterile regions of the lower respiratory tract, which leads to pneumonia. In this Review, we describe how S. pneumoniae uses its armamentarium of virulence factors to colonize the upper and lower respiratory tracts of the host and cause disease.
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Affiliation(s)
- Aras Kadioglu
- Department of Infection, Immunity & Inflammation, University of Leicester, Leicester LE1 9HN, United Kingdom.
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30
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Witzenrath M, Gutbier B, Owen JS, Schmeck B, Mitchell TJ, Mayer K, Thomas MJ, Ishii S, Rosseau S, Suttorp N, Schütte H. Role of platelet-activating factor in pneumolysin-induced acute lung injury. Crit Care Med 2007; 35:1756-62. [PMID: 17522574 DOI: 10.1097/01.ccm.0000269212.84709.23] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Acute respiratory failure is a major complication of severe pneumococcal pneumonia, characterized by impairment of pulmonary microvascular barrier function and pulmonary hypertension. Both features can be evoked by pneumolysin (PLY), an important virulence factor of Streptococcus pneumoniae. We hypothesized that platelet-activating factor (PAF) and associated downstream signaling pathways play a role in the PLY-induced development of acute lung injury. DESIGN Controlled, ex vivo laboratory study. SUBJECTS Female Balb/C mice, 8-12 wks old. INTERVENTIONS Ventilated and blood-free-perfused lungs of wild-type and PAF receptor-deficient mice were challenged with recombinant PLY. MEASUREMENTS AND MAIN RESULTS Intravascular PLY, but not the pneumolysoid Pd-B (PLY with a Trp-Phe substitution at position 433), caused an impressive dose-dependent increase in pulmonary vascular resistance and increased PAF in lung homogenates, as detected by reversed-phase high-performance liquid chromatography coupled to tandem mass spectrometry. The pressor response was reduced in lungs of PAF receptor-deficient mice and after PAF receptor blockade by BN 50730. PLY and exogenous PAF increased thromboxane B2 in lung effluate, and thromboxane receptor inhibition by BM 13505 diminished the pressor response to PLY. Differential inhibition of intracellular signaling steps suggested significant contribution of phosphatidylcholine-specific phospholipase C and protein kinase C and of the Rho/Rho-kinase pathway to PLY-induced pulmonary vasoconstriction. Unrelated to the pulmonary arterial pressor response, microvascular leakage of PLY was diminished in lungs of PAF receptor-deficient mice as well. CONCLUSIONS PAF significantly contributed to PLY-induced acute injury in murine lungs. The PAF-mediated pressor response to PLY depends on thromboxane and on the downstream effectors phosphatidylcholine-specific phospholipase C, protein kinase C, and Rho-kinase.
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Affiliation(s)
- Martin Witzenrath
- Department of Internal Medicine/Infectious Diseases and Respiratory Medicine, Charité-Universitätsmedizin Berlin, Germany
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Marquart ME, Monds KS, McCormick CC, Dixon SN, Sanders ME, Reed JM, McDaniel LS, Caballero AR, O'Callaghan RJ. Cholesterol as treatment for pneumococcal keratitis: cholesterol-specific inhibition of pneumolysin in the cornea. Invest Ophthalmol Vis Sci 2007; 48:2661-6. [PMID: 17525197 PMCID: PMC2814300 DOI: 10.1167/iovs.07-0017] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The purpose of this study was to determine whether cholesterol, the host cell receptor for pneumolysin of Streptococcus pneumoniae, could effectively treat pneumococcal keratitis. METHODS New Zealand White rabbits were intrastromally injected with 10(5) colony-forming units (CFUs) of S. pneumoniae D39. Corneas were treated with topical drops of 1% cholesterol every 2 hours beginning 25 hours after infection and were examined by slit lamp microscopy 24, 36, and 48 hours after infection. Rabbits were killed, and CFUs were recovered from the corneas after the final slit lamp examination (SLE). Minimal inhibitory concentration (MIC) assays of cholesterol against bacteria were performed. Specific inhibition of pneumolysin by cholesterol in the rabbit cornea was tested by intrastromal injection of pneumolysin with or without cholesterol and was compared with cholesterol inhibition of pneumolysin in vitro using hemolysis assays with rabbit erythrocytes. RESULTS Corneas treated with cholesterol had significantly lower SLE scores 48 hours after infection than corneas treated with vehicle (P = 0.0015). Treated corneas also had significantly less log(10) CFUs than vehicle-treated corneas (P = 0.0006). Cholesterol at a 1% concentration was bactericidal to bacteria in vitro, and lower concentrations of cholesterol were partially inhibitory in a concentration-dependent manner. Cholesterol also specifically inhibited 1 mug pneumolysin in vivo and up to 50 ng pneumolysin in vitro. CONCLUSIONS Topical cholesterol is an effective treatment for S. pneumoniae keratitis. Cholesterol not only inhibits pneumolysin, it is also bactericidal.
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Affiliation(s)
- Mary E Marquart
- Department of Microbiology, University of Mississippi Medical Center, Jackson, Mississippi 39216, USA.
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Marks M, Burns T, Abadi M, Seyoum B, Thornton J, Tuomanen E, Pirofski LA. Influence of neutropenia on the course of serotype 8 pneumococcal pneumonia in mice. Infect Immun 2007; 75:1586-97. [PMID: 17296760 PMCID: PMC1865693 DOI: 10.1128/iai.01579-06] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Polymorphoneutrophils (PMNs) are important effector cells in host defense against pneumonia. However, PMNs can also induce inflammation and tissue damage. To investigate the contribution of PMNs to host defense against pneumococcal pneumonia, we determined the effect of the PMN-depleting rat monoclonal antibody RB6-8C5 (RB6) on survival and inflammatory and cellular response in the lungs to a lethal intranasal infection with a serotype 8 pneumococcus in BALB/c mice. Control mice received rat immunoglobulin G (rIgG). Strikingly, the survival of RB6-treated mice was significantly prolonged compared to that of rIgG-treated mice. Although the numbers of CFU in the lungs were statistically similar in both groups 4, 24, and 32 h after infection, rIgG-treated mice developed higher levels of bacteremia, and histopathological examination of the lungs of infected mice revealed marked differences between RB6- and rIgG-treated mice. RB6-treated mice had focal, perivascular lesions without accompanying parenchymal inflammation, and rIgG-treated mice had diffuse, interstitial parenchymal inflammation. Lung homogenates from the rIgG-treated mice had more leukocytes and significantly more total and apoptotic PMNs as determined by fluorescence-activated cell sorter analysis with Annexin V and terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling staining of lung tissue samples. Studies with a pneumolysin-deficient mutant of the serotype 8 strain we used also demonstrated the prolonged survival of RB6- compared to rIgG-treated mice. Taken together, our findings suggest that PMNs enhance the likelihood of early death and alter the pathological response to pneumococcal lung infection in BALB/c mice with serotype 8 pneumonia without significantly affecting bacterial clearance or the cytokine response.
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Affiliation(s)
- Matthew Marks
- Division of Infectious Diseases, Albert Einstein College of Medicine, Forchheimer Bldg., 1300 Morris Park Avenue, Bronx, NY 10461, USA
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García-Suárez MDM, Flórez N, Astudillo A, Vázquez F, Villaverde R, Fabrizio K, Pirofski LA, Méndez FJ. The role of pneumolysin in mediating lung damage in a lethal pneumococcal pneumonia murine model. Respir Res 2007; 8:3. [PMID: 17257395 PMCID: PMC1790890 DOI: 10.1186/1465-9921-8-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2006] [Accepted: 01/26/2007] [Indexed: 01/28/2023] Open
Abstract
Background Intranasal inoculation of Streptococcus pneumoniae D39 serotype 2 causes fatal pneumonia in mice. The cytotoxic and inflammatory properties of pneumolysin (PLY) have been implicated in the pathogenesis of pneumococcal pneumonia. Methods To examine the role of PLY in this experimental model we performed ELISA assays for PLY quantification. The distribution patterns of PLY and apoptosis were established by immunohistochemical detection of PLY, caspase-9 activity and TUNEL assay on tissue sections from mice lungs at various times, and the results were quantified with image analysis. Inflammatory and apoptotic cells were also quantified on lung tissue sections from antibody treated mice. Results In bronchoalveolar lavages (BAL), total PLY was found at sublytic concentrations which were located in alveolar macrophages and leukocytes. The bronchoalveolar epithelium was PLY-positive, while the vascular endothelium was not PLY reactive. The pattern and extension of cellular apoptosis was similar. Anti-PLY antibody treatment decreased the lung damage and the number of apoptotic and inflammatory cells in lung tissues. Conclusion The data strongly suggest that in vivo lung injury could be due to the pro-apoptotic and pro-inflammatory activity of PLY, rather than its cytotoxic activity. PLY at sublytic concentrations induces lethal inflammation in lung tissues and is involved in host cell apoptosis, whose effects are important to pathogen survival.
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Affiliation(s)
- María del Mar García-Suárez
- Área de Microbiología, Departamento de Biología Funcional, Instituto Universitario de Biotecnología de Asturias (IUBA), Universidad de Oviedo; 33006 Oviedo, Asturias, Spain
| | - Noelia Flórez
- Área de Microbiología, Departamento de Biología Funcional, Instituto Universitario de Biotecnología de Asturias (IUBA), Universidad de Oviedo; 33006 Oviedo, Asturias, Spain
| | - Aurora Astudillo
- Laboratorio de Anatomía Patológica, Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Universidad de Oviedo; 33006 Oviedo, Asturias, Spain
| | - Fernando Vázquez
- Área de Microbiología, Departamento de Biología Funcional, Instituto Universitario de Biotecnología de Asturias (IUBA), Universidad de Oviedo; 33006 Oviedo, Asturias, Spain
| | - Roberto Villaverde
- Área de Microbiología, Departamento de Biología Funcional, Instituto Universitario de Biotecnología de Asturias (IUBA), Universidad de Oviedo; 33006 Oviedo, Asturias, Spain
| | - Kevin Fabrizio
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA
| | - Liise-Anne Pirofski
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA
- Division of Infectious Diseases, Department of Medicine, Albert Einstein College of Medicine and Montefiore Medical Center, 1300 Morris Park Avenue, Bronx, New York 10461, USA
| | - Francisco J Méndez
- Área de Microbiología, Departamento de Biología Funcional, Instituto Universitario de Biotecnología de Asturias (IUBA), Universidad de Oviedo; 33006 Oviedo, Asturias, Spain
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Feterl M, Govan B, Engler C, Norton R, Ketheesan N. Activity of tigecycline in the treatment of acute Burkholderia pseudomallei infection in a murine model. Int J Antimicrob Agents 2007; 28:460-4. [PMID: 17046208 DOI: 10.1016/j.ijantimicag.2006.07.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2006] [Revised: 07/19/2006] [Accepted: 07/20/2006] [Indexed: 11/19/2022]
Abstract
Burkholderia pseudomallei is the causative agent of melioidosis. Standard therapy includes ceftazidime alone or in combination with co-trimoxazole. Tigecycline, a novel agent, has displayed activity against B. pseudomallei. We evaluated the in vivo efficacy of tigecycline using a murine model of melioidosis. Mice were infected with either a high or low virulence B. pseudomallei isolate followed by administration of antibiotics alone or in combination (tigecycline, ceftazidime, tigecycline plus ceftazidime) for 7 days. Bacterial loads were assessed up to 7 days and survival was determined up to 7 days post infection. Tigecycline in combination with ceftazidime was the most effective and conferred the lowest mortality, suggesting the use of this new agent in B. pseudomallei infection.
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Affiliation(s)
- Marshall Feterl
- School of Veterinary and Biomedical Sciences, James Cook University, Townsville, Qld 4811, Australia
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Feldman C, Anderson R. Controversies in the treatment of pneumococcal community-acquired pneumonia. Future Microbiol 2006; 1:271-81. [PMID: 17661640 DOI: 10.2217/17460913.1.3.271] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Community-acquired pneumonia remains an important cause of disease and death both in the developed and the developing worlds, despite the ready availability of potent antimicrobial agents to which the organisms remain susceptible. Furthermore, disease management is complicated by emerging resistance of the common pathogens to the various classes of commonly prescribed antimicrobial agents. Much recent research in the field of community-acquired pneumonia has focused attention on optimal treatment, evaluating the impact of antibiotic resistance, as well as of antimicrobial choices, on the outcome of these infections. In addition, efforts have been directed towards finding adjunctive therapies to antibiotics that may improve the prognosis of these patients. This article reviews some of these research areas, highlighting controversies that still exist with regard to final recommendations, and in particular with regard to infections with Streptococcus pneumoniae, the most common bacterial cause of community-acquired pneumonia.
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Affiliation(s)
- Charles Feldman
- University of the Witwatersrand Medical School, Division of Pulmonology, Department of Medicine, Parktown, Johannesburg, South Africa.
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Witzenrath M, Gutbier B, Hocke AC, Schmeck B, Hippenstiel S, Berger K, Mitchell TJ, de los Toyos JR, Rosseau S, Suttorp N, Schütte H. Role of pneumolysin for the development of acute lung injury in pneumococcal pneumonia. Crit Care Med 2006; 34:1947-54. [PMID: 16715037 DOI: 10.1097/01.ccm.0000220496.48295.a9] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Acute respiratory failure is a significant complication of severe pneumococcal pneumonia. In a mouse model, we observed early-onset lung microvascular leakage after pulmonary infection with Streptococcus pneumoniae, and we hypothesized that the important virulence factor pneumolysin may be the direct causative agent. DESIGN Controlled, in vivo, ex vivo, and in vitro laboratory study. SETTING Laboratory. SUBJECTS Female mice, 8-12 wks old. INTERVENTIONS Ventilated and blood-free perfused murine lungs were challenged with recombinant pneumolysin via the airways as well as via the vascular bed. In addition, we analyzed the impact of pneumolysin on electrical cell impedance and hydraulic conductivity of human umbilical vein endothelial cell (HUVEC) and alveolar epithelial cell (A549) monolayers. MEASUREMENTS AND MAIN RESULTS Aerosolized pneumolysin dose-dependently increased capillary permeability with formation of severe lung edema but did not affect pulmonary vascular resistance. Intravascular pneumolysin caused an impressive dose-dependent increase in pulmonary vascular resistance and in lung microvascular permeability. By immunohistochemistry, pneumolysin was detected mainly in endothelial cells of pulmonary arterial vessels, which concomitantly displayed strong vasoconstriction. Moreover, pneumolysin increased permeability of HUVEC and A549 monolayers. Interestingly, immunofluorescence of endothelial cell monolayers exposed to pneumolysin showed gap formation and moderate stress fiber generation. CONCLUSIONS Pneumolysin may play a central role for early-onset acute lung injury due to severe pneumococcal pneumonia by causing impairment of pulmonary microvascular barrier function and severe pulmonary hypertension.
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Affiliation(s)
- Martin Witzenrath
- Charité-Universitätsmedizin Berlin, Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine, Berlin, Germany
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Abstract
The innate immune system provides a non-specific first line of defence against microbes and is crucial both in the development and effector stages of subsequent adaptive immune responses. Consistent with its importance, study of the innate immune system is a broad and fast-moving field. Here we provide an overview of the recent key advances made in this area with relation to the important pathogen Streptococcus pneumoniae (the pneumococcus).
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Affiliation(s)
- Gavin K Paterson
- Division of Infection and Immunity, University of Glasgow, Glasgow G12 8QQ, UK
| | - Tim J Mitchell
- Division of Infection and Immunity, University of Glasgow, Glasgow G12 8QQ, UK
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Watanabe I, Nomura T, Tominaga T, Yamamoto K, Kohda C, Kawamura I, Mitsuyama M. Dependence of the lethal effect of pore-forming haemolysins of Gram-positive bacteria on cytolytic activity. J Med Microbiol 2006; 55:505-510. [PMID: 16585635 DOI: 10.1099/jmm.0.46333-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Among bacterial haemolysins, cholesterol-dependent cytolysins (CDCs) produced by various Gram-positive bacteria are known to exhibit a lethal activity in mice. In this study, recombinant CDCs of streptolysin O, pneumolysin, ivanolysin O, listeriolysin O and several listeriolysin O mutants were constructed and the relationship between cytolytic activity and the lethal activity of each recombinant protein in mice was examined. Specific activity for cytolysis was determined by a quantitative haemolytic assay. Each protein was injected intravenously into mice and the lethal activity was evaluated by measuring the time until death of the mice. The four full-length CDC proteins exhibited lethal activity and their activities were highly proportional to their cytolytic activities. Inhibition of haemolytic activity resulted in the loss of lethal activity and non-haemolytic mutants of listeriolysin O did not exhibit any lethal activity. These data clearly indicate that the lethal effect of CDC proteins is dependent on the cytolytic activity.
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Affiliation(s)
- Isao Watanabe
- Department of Microbiology, Kyoto University Graduate School of Medicine, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Takamasa Nomura
- Department of Microbiology, Kyoto University Graduate School of Medicine, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Takanari Tominaga
- Department of Microbiology, Kyoto University Graduate School of Medicine, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Kazuhiro Yamamoto
- Department of Microbiology, Kyoto University Graduate School of Medicine, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Chikara Kohda
- Department of Bacteriology, Showa University School of Medicine, Tokyo 142-8555, Japan
| | - Ikuo Kawamura
- Department of Microbiology, Kyoto University Graduate School of Medicine, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Masao Mitsuyama
- Department of Microbiology, Kyoto University Graduate School of Medicine, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
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Moreland JG, Bailey G. Neutrophil transendothelial migration in vitro to Streptococcus pneumoniae is pneumolysin dependent. Am J Physiol Lung Cell Mol Physiol 2005; 290:L833-40. [PMID: 16339781 DOI: 10.1152/ajplung.00333.2005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The recruitment of polymorphonuclear leukocytes (PMN) from the vascular space to the alveolar air space is an early event in host defense against pneumococcal pneumonia. Pneumolysin is a virulence factor for Streptococcus pneumoniae, but a specific role for pneumolysin in neutrophil-endothelial cell interactions has not been investigated. Using a Transwell system, we studied in vitro migration of PMNs across a monolayer of human pulmonary microvascular endothelial cells in response to wild-type S. pneumoniae (D39) and a pneumolysin-deficient mutant (plnA(-)) incubated on the abluminal surface of the monolayer. S. pneumoniae induction of PMN migration was dose dependent and elicited by > or =10(5) D39. Mutants lacking pneumolysin had dramatically reduced potency for eliciting PMN migration compared with the parent strain (5 x 10(6) plnA(-) elicits 18.6% PMN migration vs. 55.5% for 5 x 10(6) D39). The disparity between D39 and plnA(-) persisted in ethanol-fixed bacteria, consistent with the properties of pneumolysin. Neither conditioned medium from D39 nor purified pneumolysin elicited PMN migration to the same extent as the intact D39, suggesting that the role of pneumolysin in eliciting PMN migration requires a more complex interaction between the organism, the endothelium, and the PMN. Both D39 and plnA(-) adhered to, and translocated across, the endothelium in the abluminal to luminal direction and elicited similar levels of IL-8 production. Neither strain elicited upregulation of the endothelial adhesion molecules ICAM-1, VCAM-1, or E-selectin, and they did not cause translocation of NF-kappaB to the nucleus. These findings demonstrate a novel role for pneumolysin in pneumococcus-induced PMN recruitment across the pulmonary endothelium.
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Affiliation(s)
- Jessica G Moreland
- Division of Pediatric Critical Care, Department of Pediatrics/2JCP, The University of Iowa, Iowa City, IA 52242, USA.
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Srivastava A, Henneke P, Visintin A, Morse SC, Martin V, Watkins C, Paton JC, Wessels MR, Golenbock DT, Malley R. The apoptotic response to pneumolysin is Toll-like receptor 4 dependent and protects against pneumococcal disease. Infect Immun 2005; 73:6479-87. [PMID: 16177320 PMCID: PMC1230904 DOI: 10.1128/iai.73.10.6479-6487.2005] [Citation(s) in RCA: 137] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Pneumolysin, the cholesterol-dependent cytolysin of Streptococcus pneumoniae, induces inflammatory and apoptotic events in mammalian cells. Toll-like receptor 4 (TLR4) confers resistance to pneumococcal infection via its interaction with pneumolysin, but the underlying mechanisms remain to be identified. In the present study, we found that pneumolysin-induced apoptosis is also mediated by TLR4 and confers protection against invasive disease. The interaction between TLR4 and pneumolysin is direct and specific; ligand-binding studies demonstrated that pneumolysin binds to TLR4 but not to TLR2. Involvement of TLR4 in pneumolysin-induced apoptosis was demonstrated in several complementary experiments. First, macrophages from wild-type mice were significantly more prone to pneumolysin-induced apoptosis than cells from TLR4-defective mice. In gain-of-function experiments, we found that epithelial cells expressing TLR4 and stimulated with pneumolysin were more likely to undergo apoptosis than cells expressing TLR2. A specific TLR4 antagonist, B1287, reduced pneumolysin-mediated apoptosis in wild-type cells. This apoptotic response was also partially caspase dependent as preincubation of cells with the pan-caspase inhibitor zVAD-fmk reduced pneumolysin-induced apoptosis. Finally, in a mouse model of pneumococcal infection, pneumolysin-producing pneumococci elicited significantly more upper respiratory tract cell apoptosis in wild-type mice than in TLR4-defective mice, and blocking apoptosis by administration of zVAD-fmk to wild-type mice resulted in a significant increase in mortality following nasopharyngeal pneumococcal exposure. Overall, our results strongly suggest that protection against pneumococcal disease is dependent on the TLR4-mediated enhancement of pneumolysin-induced apoptosis.
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Affiliation(s)
- Amit Srivastava
- Division of Infectious Diseases, Department of Medicine, Children's Hospital, Boston, MA 02115, USA
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Thornton J, McDaniel LS. THP-1 monocytes up-regulate intercellular adhesion molecule 1 in response to pneumolysin from Streptococcus pneumoniae. Infect Immun 2005; 73:6493-8. [PMID: 16177322 PMCID: PMC1230928 DOI: 10.1128/iai.73.10.6493-6498.2005] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pneumolysin (PLY) is a major virulence factor of Streptococcus pneumoniae that elicits a variety of proinflammatory responses from cells of the host immune system. Intercellular adhesion molecule 1 (ICAM-1) is a cell adhesion molecule involved in leukocyte trafficking toward inflammatory stimuli in extravascular sites. In this study, we evaluated the effect of PLY on expression of ICAM-1 in THP-1 monocytic cells exposed to S. pneumoniae. Exposure of cells to PLY-expressing S. pneumoniae strain WU2 for 6 h led to significantly higher levels of ICAM-1 message than those in cells exposed to either medium alone or DeltaPLY1, a PLY-negative isogenic mutant of WU2. Cells exposed to purified recombinant PLY also showed a dose-dependent increase in ICAM-1 mRNA compared to cells exposed to medium alone. Exposure to recombinant PLY containing a single amino acid substitution (Trp433-->Phe) that decreases cytolytic activity did not increase ICAM-1 mRNA to levels seen with wild-type PLY. In addition, THP-1 cells exposed to wild-type strain WU2 or D39 had increased ICAM-1 on their surface compared to cells exposed to medium alone or their PLY-negative isogenic mutants DeltaPLY1 and DeltaPLY2, respectively. These data indicate that PLY induces transcription and production of a cell adhesion molecule involved in the inflammatory response that may play a role in pneumococcal infection.
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Affiliation(s)
- Justin Thornton
- Department of Microbiology, University of Mississippi Medical Center, Jackson, 39216, USA
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Jounblat R, Clark H, Eggleton P, Hawgood S, Andrew PW, Kadioglu A. The role of surfactant protein D in the colonisation of the respiratory tract and onset of bacteraemia during pneumococcal pneumonia. Respir Res 2005; 6:126. [PMID: 16255775 PMCID: PMC1282592 DOI: 10.1186/1465-9921-6-126] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2005] [Accepted: 10/28/2005] [Indexed: 01/02/2023] Open
Abstract
We have shown previously that surfactant protein D (SP-D) binds and agglutinates Streptococcus pneumoniae in vitro. In this study, the role of SP-D in innate immunity against S. pneumoniae was investigated in vivo, by comparing the outcome of intranasal infection in surfactant protein D deficient (SP-D-/-) to wildtype mice (SP-D+/+). Deficiency of SP-D was associated with enhanced colonisation and infection of the upper and lower respiratory tract and earlier onset and longer persistence of bacteraemia. Recruitment of neutrophils to inflammatory sites in the lung was similar in both strains mice in the first 24 hrs post-infection, but different by 48 hrs. T cell influx was greatly enhanced in SP-D-/- mice as compared to SP-D+/+ mice. Our data provides evidence that SP-D has a significant role to play in the clearance of pneumococci during the early stages of infection in both pulmonary sites and blood.
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Affiliation(s)
- R Jounblat
- MRC Immunochemistry Unit, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - H Clark
- MRC Immunochemistry Unit, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - P Eggleton
- Institute of Biomedical and Clinical Sciences, Peninsula Medical School, Exeter, EX1 2LU, UK
| | - S Hawgood
- Cardiovascular Research Institute and Department of Paediatrics, University of California, San Francisco, San Francisco, California, USA
| | - PW Andrew
- Department of Infection Immunity and Inflammation, University of Leicester, Leicester, LE1 9HN, UK
| | - A Kadioglu
- Department of Infection Immunity and Inflammation, University of Leicester, Leicester, LE1 9HN, UK
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Affiliation(s)
- Rodney K Tweten
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, 73104, USA.
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44
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Pracht D, Elm C, Gerber J, Bergmann S, Rohde M, Seiler M, Kim KS, Jenkinson HF, Nau R, Hammerschmidt S. PavA of Streptococcus pneumoniae modulates adherence, invasion, and meningeal inflammation. Infect Immun 2005; 73:2680-9. [PMID: 15845469 PMCID: PMC1087317 DOI: 10.1128/iai.73.5.2680-2689.2005] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pneumococcal adherence and virulence factor A (PavA) is displayed to the cell outer surface of Streptococcus pneumoniae and mediates pneumococcal binding to immobilized fibronectin. PavA, which lacks a typical gram-positive signal sequence and cell surface anchorage motif, is essential for pneumococcal virulence in a mouse infection model of septicemia. In this report the impact of PavA on pneumococcal adhesion to and invasion of eukaryotic cells and on experimental pneumococcal meningitis was investigated. In the experimental mouse meningitis model, the virulence of the pavA knockout mutant of S. pneumoniae D39, which did not show alterations of subcellular structures as indicated by electron microscopic studies, was strongly decreased. Pneumococcal strains deficient in PavA showed substantially reduced adherence to and internalization of epithelial cell lines A549 and HEp-2. Similar results were obtained with human brain-derived microvascular endothelial cells and human umbilical vein-derived endothelial cells. Attachment and internalization of pneumococci were not significantly affected by preincubation or cocultivations of pneumococci with anti-PavA antisera. Pneumococcal adherence was also not significantly affected by the addition of PavA protein. Complementation of the pavA knockout strain with exogenously added PavA polypeptide did not restore adherence of the mutant. These data suggest that PavA affects pneumococcal colonization by modulating expression or function of important virulence determinants of S. pneumoniae.
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Affiliation(s)
- Daniela Pracht
- Research Center for Infectious Diseases, University of Würzburg, Röntgenring 11, D-97070 Würzburg, Germany
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Fickl H, Cockeran R, Steel HC, Feldman C, Cowan G, Mitchell TJ, Anderson R. Pneumolysin-mediated activation of NFkappaB in human neutrophils is antagonized by docosahexaenoic acid. Clin Exp Immunol 2005; 140:274-81. [PMID: 15807851 PMCID: PMC1809376 DOI: 10.1111/j.1365-2249.2005.02757.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
This study was designed to investigate the relationship between influx of extracellular Ca(2+), activation of NFkappaB and synthesis of interleukin-8 (IL-8) following exposure of human neutrophils to subcytolytic concentrations (8.37 and 41.75 ng/ml) of the pneumococcal toxin, pneumolysin, as well as the potential of the omega-3 polyunsaturated fatty acid, docosahexaenoic acid, to antagonize these events. Activation and translocation of NFkappaB were measured using a radiometric electrophoretic mobility shift assay, while influx of extracellular Ca(2+) and synthesis of IL-8 were determined using a radioassay and an ELISA procedure, respectively. Exposure of neutrophils to pneumolysin was accompanied by influx of Ca(2+), activation of NFkappaB, and synthesis of IL-8, all of which were eliminated by inclusion of the Ca(2+)-chelating agent, EGTA (10 m m), in the cell-suspending medium, as well as by pretreatment of the cells with docosahexaenoic acid (5 and 10 microg/ml). The antagonistic effects of docosahexaenoic acid on these pro-inflammatory interactions of pneumolysin with neutrophils were not attributable to inactivation of the toxin, and required the continuous presence of the fatty acid. These observations demonstrate that activation of NFkappaB and synthesis of IL-8, following exposure of neutrophils to pneumolysin are dependent on toxin-mediated influx of Ca(2+) and that these potentially harmful activities of the toxin are antagonized by docosahexaenoic acid.
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Affiliation(s)
- H Fickl
- Medical Research Council Unit for Inflammation and Immunity, Department of Immunology, University of PretoriaPretoria
| | - R Cockeran
- Medical Research Council Unit for Inflammation and Immunity, Department of Immunology, University of PretoriaPretoria
| | - H C Steel
- Medical Research Council Unit for Inflammation and Immunity, Department of Immunology, University of PretoriaPretoria
| | - C Feldman
- Division of Pulmonology, Department of Medicine, Johannesburg Hospital and University of the WitwatersrandJohannesburg, South Africa
| | - G Cowan
- Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of GlasgowGlasgow, UK
| | - T J Mitchell
- Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of GlasgowGlasgow, UK
| | - R Anderson
- Medical Research Council Unit for Inflammation and Immunity, Department of Immunology, University of PretoriaPretoria
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Neeleman C, Klaassen CHW, Klomberg DM, de Valk HA, Mouton JW. Pneumolysin is a key factor in misidentification of macrolide-resistant Streptococcus pneumoniae and is a putative virulence factor of S. mitis and other streptococci. J Clin Microbiol 2004; 42:4355-7. [PMID: 15365043 PMCID: PMC516304 DOI: 10.1128/jcm.42.9.4355-4357.2004] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We evaluated the applicability of ply PCR for confirmation of the identification of Streptococcus pneumoniae. lytA PCR, 16S rRNA sequencing, and amplified-fragment length polymorphism were used as reference methods. In contrast to the lytA gene, the ply gene proved to be not specific for S. pneumoniae. The presence of the ply gene in other streptococci, in particular Streptococcus mitis, suggests that pneumolysin plays a pathogenic role.
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Affiliation(s)
- Chris Neeleman
- Department of Intensive Care Medicine, University Hospital St. Radboud, Nijmegen, The Netherlands
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Hirst RA, Kadioglu A, O'callaghan C, Andrew PW. The role of pneumolysin in pneumococcal pneumonia and meningitis. Clin Exp Immunol 2004; 138:195-201. [PMID: 15498026 PMCID: PMC1809205 DOI: 10.1111/j.1365-2249.2004.02611.x] [Citation(s) in RCA: 157] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Diseases caused by Streptococcus pneumoniae include pneumonia, septicaemia and meningitis. All these are associated with high morbidity and mortality. The pneumococcus can colonize the nasopharynx, and this can be a prelude to bronchopneumonia and invasion of the vasculature space. Proliferation in the blood can result in a breach of the blood-brain barrier and entry into the cerebrospinal fluid (CSF) where the bacteria cause inflammation of the meningeal membranes resulting in meningitis. The infected host may develop septicaemia and/or meningitis secondary to bronchopneumonia. Also septicaemia is a common precursor of meningitis. The mechanisms surrounding the sequence of infection are unknown, but will be dependent on the properties of both the host and bacterium. Treatment of these diseases with antibiotics leads to clearance of the bacteria from the infected tissues, but the bacteriolytic nature of antibiotics leads to an acute release of bacterial toxins and thus after antibiotic therapy the patients can be left with organ-specific deficits. One of the main toxins released from pneumococci is the membrane pore forming toxin pneumolysin. Here we review the extensive studies on the role of pneumolysin in the pathogenesis of pneumococcal diseases.
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Affiliation(s)
- R A Hirst
- Department of Infection, Inflamation and Immunity, University of Leicester, Leicester, UK.
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Cockeran R, Anderson R, Feldman C. Pneumolysin in the immunopathogenesis and treatment of pneumococcal disease. Expert Rev Anti Infect Ther 2004; 1:231-9. [PMID: 15482118 DOI: 10.1586/14787210.1.2.231] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Recent insights into the immunopathogenesis of pneumococcal infection, a common and significant cause of morbidity and mortality, have implicated pneumolysin as being a prominent virulence factor, which may play a role in microbial colonization, invasion and dissemination, as well as tissue inflammation. Being a highly immunogenic polypeptide produced by all clinically relevant pneumococcal isolates, pneumolysin is recognized as a potential carrier protein for polysaccharide conjugate vaccines, while in the setting of acute disease, promising pneumolysin-directed pharmacological strategies include, among others, macrolides and corticosteroids.
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Cockeran R, Theron AJ, Feldman C, Mitchell TJ, Anderson R. Docosahexaenoic acid and eicosapentaenoic acid antagonize the proinflammatory interactions of pneumolysin with human neutrophils. Infect Immun 2004; 72:4327-9. [PMID: 15213185 PMCID: PMC427396 DOI: 10.1128/iai.72.7.4327-4329.2004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pneumolysin (4.18 ng/ml)-mediated influx of Ca(2+) and augmentation of the chemoattractant-activated generation of reactive oxidants was antagonized by pretreatment of human neutrophils with the omega-3 polyunsaturated fatty acids docosahexaenoic acid and eicosapentaenoic acid (1.25 to 5 microg/ml). These agents may have potential in attenuating the proinflammatory properties of this pneumococcal toxin.
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Affiliation(s)
- Riana Cockeran
- Medical Research Council for Inflammation and Immunity, Department of Immunology, Faculty of Health Sciences, University of Pretoria, P.O. Box 2034, Pretoria 0001, South Africa.
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Kadioglu A, Coward W, Colston MJ, Hewitt CRA, Andrew PW. CD4-T-lymphocyte interactions with pneumolysin and pneumococci suggest a crucial protective role in the host response to pneumococcal infection. Infect Immun 2004; 72:2689-97. [PMID: 15102777 PMCID: PMC387852 DOI: 10.1128/iai.72.5.2689-2697.2004] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previously, we had shown that T cells accumulated in peribronchiolar and perivascular areas of lungs soon after intranasal infection with Streptococcus pneumoniae. We have now presented new evidence, using major histocompatibility class II-deficient mice, that CD4 cells are important for early protective immunity. In addition, we have also shown that a population of human CD4 cells migrates towards pneumococci and that in vivo-passaged pneumococci are substantially more potent at inducing migration than in vitro-grown bacteria. This migratory process is unique to a specific population of CD4 cells, is highly reproducible, and is independent of prior CD4 cell activation, and yet the migratory process results in a significant proportion of CD4 cells becoming activated. The production of pneumolysin is a key facet in the induction of migration of CD4 cells by in vivo bacteria, as pneumolysin-deficient bacteria do not induce migration, but the data also show that pneumolysin alone is not sufficient to explain the enhanced migration. Increased CD25 expression occurs during migration, and a higher percentage of cells in the migrated population express gamma interferon or interleukin 4 (IL-4) than in the population that did not migrate. There is evidence that the activation of IL-4 expression occurs during migration.
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Affiliation(s)
- Aras Kadioglu
- Department of Infection, Immunity & Inflammation, University of Leicester, Leicester LE1 9HN, United Kingdom.
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