1
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Naturally-occurring serotype 3 Streptococcus pneumoniae strains that lack functional pneumolysin and autolysin have attenuated virulence but induce localized protective immune responses. PLoS One 2023; 18:e0282843. [PMID: 36897919 PMCID: PMC10004606 DOI: 10.1371/journal.pone.0282843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Accepted: 02/23/2023] [Indexed: 03/11/2023] Open
Abstract
Streptococcus pneumoniae is an important cause of fatal pneumonia in humans. These bacteria express virulence factors, such as the toxins pneumolysin and autolysin, that drive host inflammatory responses. In this study we confirm loss of pneumolysin and autolysin function in a group of clonal pneumococci that have a chromosomal deletion resulting in a pneumolysin-autolysin fusion gene Δ(lytA'-ply')593. The Δ(lytA'-ply')593 pneumococci strains naturally occur in horses and infection is associated with mild clinical signs. Here we use immortalized and primary macrophage in vitro models, which include pattern recognition receptor knock-out cells, and a murine acute pneumonia model to show that a Δ(lytA'-ply')593 strain induces cytokine production by cultured macrophages, however, unlike the serotype-matched ply+lytA+ strain, it induces less tumour necrosis factor α (TNFα) and no interleukin-1β production. The TNFα induced by the Δ(lytA'-ply')593 strain requires MyD88 but, in contrast to the ply+lytA+ strain, is not reduced in cells lacking TLR2, 4 or 9. In comparison to the ply+lytA+ strain in a mouse model of acute pneumonia, infection with the Δ(lytA'-ply')593 strain resulted in less severe lung pathology, comparable levels of interleukin-1α, but minimal release of other pro-inflammatory cytokines, including interferon-γ, interleukin-6 and TNFα. These results suggest a mechanism by which a naturally occurring Δ(lytA'-ply')593 mutant strain of S. pneumoniae that resides in a non-human host has reduced inflammatory and invasive capacity compared to a human S. pneumoniae strain. These data probably explain the relatively mild clinical disease in response to S. pneumoniae infection seen in horses in comparison to humans.
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2
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Periselneris J, Turner CT, Ercoli G, Szylar G, Weight CM, Thurston T, Whelan M, Tomlinson G, Noursadeghi M, Brown J. Pneumolysin suppresses the initial macrophage pro-inflammatory response to Streptococcus pneumoniae. Immunology 2022; 167:413-427. [PMID: 35835695 PMCID: PMC10497322 DOI: 10.1111/imm.13546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 07/04/2022] [Indexed: 12/01/2022] Open
Abstract
Published data for the Streptococcus pneumoniae virulence factor Pneumolysin (Ply) show contradictory effects on the host inflammatory response to infection. Ply has been shown to activate the inflammasome, but also can bind to MRC-1 resulting in suppression of dendritic cell inflammatory responses. We have used an in vitro infection model of human monocyte-derived macrophages (MDM), and a mouse model of pneumonia to clarify whether pro- or anti-inflammatory effects dominate the effects of Ply on the initial macrophage inflammatory response to S. pneumoniae, and the consequences during early lung infection. We found that infection with S. pneumoniae expressing Ply suppressed tumour necrosis factor (TNF) and interleukin-6 production by MDMs compared to cells infected with ply-deficient S. pneumoniae. This effect was independent of bacterial effects on cell death. Transcriptional analysis demonstrated S. pneumoniae expressing Ply caused a qualitatively similar but quantitatively lower MDM transcriptional response to S. pneumoniae compared to ply-deficient S. pneumoniae, with reduced expression of TNF and type I IFN inducible genes. Reduction of the MDM inflammatory response was prevented by inhibition of SOCS1. In the early lung infection mouse model, the TNF response to ply-deficient S. pneumoniae was enhanced and bacterial clearance increased compared to infection with wild-type S. pneumoniae. Overall, these data show Ply inhibits the initial macrophage inflammatory response to S. pneumoniae, probably mediated through SOCS1, and this was associated with improved immune evasion during early lung infection.
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Affiliation(s)
- Jimstan Periselneris
- Centre for Inflammation and Tissue Repair, Division of MedicineUniversity College Medical SchoolLondonUK
| | | | - Giuseppe Ercoli
- Centre for Inflammation and Tissue Repair, Division of MedicineUniversity College Medical SchoolLondonUK
| | - Gabriella Szylar
- Centre for Inflammation and Tissue Repair, Division of MedicineUniversity College Medical SchoolLondonUK
| | | | - Teresa Thurston
- MRC Centre for Molecular Bacteriology and InfectionImperial College LondonLondonUK
| | - Matthew Whelan
- Division of Infection and ImmunityUniversity College LondonLondonUK
| | | | | | - Jeremy Brown
- Centre for Inflammation and Tissue Repair, Division of MedicineUniversity College Medical SchoolLondonUK
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3
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Phagosomal Acidification Is Required to Kill Streptococcus pneumoniae in a Zebrafish Model. Cell Microbiol 2022. [DOI: 10.1155/2022/9429516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Streptococcus pneumoniae (the pneumococcus) is a major human pathogen causing invasive disease, including community-acquired bacteraemia, and remains a leading cause of global mortality. Understanding the role of phagocytes in killing bacteria is still limited, especially in vivo. In this study, we established a zebrafish model to study the interaction between intravenously administered pneumococci and professional phagocytes such as macrophages and neutrophils, to unravel bacterial killing mechanisms employed by these immune cells. Our model confirmed the key role of polysaccharide capsule in promoting pneumococcal virulence through inhibition of phagocytosis. Conversely, we show pneumococci lacking a capsule are rapidly internalised by macrophages. Low doses of encapsulated S. pneumoniae cause near 100% mortality within 48 hours postinfection (hpi), while 50 times higher doses of unencapsulated pneumococci are easily cleared. Time course analysis of in vivo bacterial numbers reveals that while encapsulated pneumococcus proliferates to levels exceeding 105 CFU at the time of host death, unencapsulated bacteria are unable to grow and are cleared within 20 hpi. Using genetically induced macrophage depletion, we confirmed an essential role for macrophages in bacterial clearance. Additionally, we show that upon phagocytosis by macrophages, phagosomes undergo rapid acidification. Genetic and chemical inhibition of vacuolar ATPase (v-ATPase) prevents intracellular bacterial killing and induces host death indicating a key role of phagosomal acidification in immunity to invading pneumococci. We also show that our model can be used to study the efficacy of antimicrobials against pneumococci in vivo. Collectively, our data confirm that larval zebrafish can be used to dissect killing mechanisms during pneumococcal infection in vivo and highlight key roles for phagosomal acidification in macrophages for pathogen clearance.
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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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Liang H, Wang B, Wang J, Ma B, Zhang W. Pyolysin of Trueperella pyogenes Induces Pyroptosis and IL-1β Release in Murine Macrophages Through Potassium/NLRP3/Caspase-1/Gasdermin D Pathway. Front Immunol 2022; 13:832458. [PMID: 35371034 PMCID: PMC8965163 DOI: 10.3389/fimmu.2022.832458] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 02/23/2022] [Indexed: 11/13/2022] Open
Abstract
Trueperella pyogenes (T. pyogenes) is a commensal and an opportunistic pathogen of animals. This organism can cause inflammatory diseases, such as pneumonia, mastitis and endometritis in hosts. However, the molecular basis for the pro-inflammatory properties of this organism is still largely unknown. In the current study, using murine macrophages as model, the ability of T. pyogenes to induce pyroptosis was first determined. Then, pyolysin (PLO), a cholesterol-dependent cytolysin secreted by T. pyogenes, was found to be closely related to T. pyogenes-induced pyroptosis. Next, our work showed that PLO can form pores in the cell membrane, leading to the efflux of potassium (K+), NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome-mediated caspase-1 activation, and gasdermin D (GSDMD) cleavage. Inhibition of the K+/NLRP3/caspase-1/GSDMD pathway abolished T. pyogenes and PLO-induced IL-1β release. Taken together, these results indicate T. pyogenes-induced inflammation is related to PLO-induced pyroptosis and IL-1β release. Our work shed light on the pathogenesis of T. pyogenes and the interaction between T. pyogenes and hosts' immune system.
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Affiliation(s)
- Hongmin Liang
- Laboratory of Veterinary Immunology, Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Northeastern Science Inspection Station, China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology, Harbin, China
| | - Bing Wang
- Laboratory of Veterinary Immunology, Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Northeastern Science Inspection Station, China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology, Harbin, China
| | - Junwei Wang
- Laboratory of Veterinary Immunology, Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Northeastern Science Inspection Station, China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology, Harbin, China
| | - Bo Ma
- Laboratory of Veterinary Immunology, Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Northeastern Science Inspection Station, China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology, Harbin, China
| | - Wenlong Zhang
- Laboratory of Veterinary Immunology, Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Northeastern Science Inspection Station, China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology, Harbin, China
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6
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Sun X, Wang D, Ding L, Xu Y, Qi W, Zhao D, Liu L, Yin C, Cui C, Wang Z, Sun L, Sun L. Activation of Autophagy Through the NLRP3/mTOR Pathway: A Potential Mechanism for Alleviation of Pneumonia by QingFei Yin. Front Pharmacol 2022; 12:763160. [PMID: 35111047 PMCID: PMC8802069 DOI: 10.3389/fphar.2021.763160] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 11/26/2021] [Indexed: 12/18/2022] Open
Abstract
QingFei Yin (QFY), a Chinese traditional medicine recipe, is known for its excellent therapeutic pharmacological effects for the treatment of bacterial lung infections, although its molecular mechanism of action remains unknown. Here, QFY chemical composition was determined using a High-Performance Liquid Chromatography-Mass (HPLC-MS/MS)-based method then QFY was evaluated for protective pharmacological effects against pneumonia using two models: a Streptococcus pneumoniae-induced in vivo mouse model and an in vitro pneumolysin (PLY)-induced murine lung alveolar-derived MH-S cell line-based model. Notably, QFY exerted prominent anti-pneumonia effects both in vivo and in vitro. To further explore QFY protective effects, 4D label-free proteomics analysis, pathologic evaluation, and immunohistochemical (IHC) analysis were conducted to identify cellular pathways involved in QFY protection. Notably, our results indicated that NF-κB/NLRP3 and autophagy pathways may contribute to pharmacological effects associated with QFY-based protection. Briefly, QFY triggered autophagy via down-regulation of upstream NLRP3/mTOR signaling pathway events, resulting in the amelioration of inflammatory injury. Collectively, our results revealed molecular mechanisms underlying QFY protection against pneumonia as a foundation for the future development of novel treatments to combat this disease and reduce antibiotic abuse.
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Affiliation(s)
- Xiaozhou Sun
- College of Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China
| | - Dandan Wang
- College of Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China.,Research Center of Traditional Chinese Medicine, The Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China
| | - Lizhong Ding
- College of Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China.,Center of Children's Clinic, The Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China
| | - Yan Xu
- College of Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China
| | - Wenxiu Qi
- Jilin Provincial Key Laboratory of Bio Macromolecules of Chinese Medicine, Jilin Ginseng Academy, Changchun University of Chinese Medicine, Changchun, China
| | - Daqing Zhao
- Jilin Provincial Key Laboratory of Bio Macromolecules of Chinese Medicine, Jilin Ginseng Academy, Changchun University of Chinese Medicine, Changchun, China
| | - Li Liu
- College of Pharmacy, Changchun University of Chinese Medicine, Changchun, China
| | - Chengcheng Yin
- College of Pharmacy, Changchun University of Chinese Medicine, Changchun, China
| | - Changsheng Cui
- College of Pharmacy, Changchun University of Chinese Medicine, Changchun, China
| | - Zhongtian Wang
- College of Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China
| | - Liwei Sun
- College of Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China.,Research Center of Traditional Chinese Medicine, The Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China
| | - Liping Sun
- College of Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China.,Center of Children's Clinic, The Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China
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7
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Lin W, Zhang J, Xu JF, Pi J. The Advancing of Selenium Nanoparticles Against Infectious Diseases. Front Pharmacol 2021; 12:682284. [PMID: 34393776 PMCID: PMC8361478 DOI: 10.3389/fphar.2021.682284] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 07/19/2021] [Indexed: 12/17/2022] Open
Abstract
Infectious diseases, caused by the direct exposure of cellular or acellular pathogens, are found to be closely associated with multiple inflammation and immune responses, keeping one of the top threats to human health. As an indispensable trace element, Selenium (Se) plays important roles in antioxidant defence and redox state regulation along with a variety of specific metabolic pathways. In recent decades, with the development of novel nanotechnology, Selenium nanoparticles (Se NPs) emerged as a promising agent for biomedical uses due to their low toxicity, degradability and high bioavailability. Taking the advantages of the strong ability to trigger apoptosis or autophagy by regulating reactive oxygen species (ROS), Se NPs have been widely used for direct anticancer treatments and pathogen killing/clearance in host cells. With excellent stability and drug encapsulation capacity, Se NPs are now serving as a kind of powerful nano-carriers for anti-cancer, anti-inflammation and anti-infection treatments. Notably, Se NPs are also found to play critical roles in immunity regulations, such as macrophage and T effector cell activation, which thus provides new possibilities to achieve novel nano-immune synergetic strategy for anti-cancer and anti-infection therapies. In this review, we summarized the progress of preparation methods for Se NPs, followed by the advances of their biological functions and mechanisms for biomedical uses, especially in the field of anti-infection treatments. Moreover, we further provide some prospects of Se NPs in anti-infectious diseases, which would be helpful for facilitating their future research progress for anti-infection therapy.
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Affiliation(s)
- Wensen Lin
- Department of Clinical Immunology, Institute of Laboratory Medicine, Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, School of Medical Technology, Guangdong Medical University, Dongguan, China
| | - Junai Zhang
- Department of Clinical Immunology, Institute of Laboratory Medicine, Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, School of Medical Technology, Guangdong Medical University, Dongguan, China
| | - Jun-Fa Xu
- Department of Clinical Immunology, Institute of Laboratory Medicine, Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, School of Medical Technology, Guangdong Medical University, Dongguan, China
| | - Jiang Pi
- Department of Clinical Immunology, Institute of Laboratory Medicine, Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, School of Medical Technology, Guangdong Medical University, Dongguan, China
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8
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Abstract
Extracellular vesicles (EVs) have recently garnered attention for their participation in host-microbe interactions in pneumococcal infections. However, the effect of EVs on the host immune system remain poorly understood. Our studies focus on EVs produced by Streptococcus pneumoniae (pEVs), and reveal that pEVs are internalized by macrophages, T cells, and epithelial cells. In vitro, pEVs induce NF-κB activation in a dosage-dependent manner and polarize human macrophages to an alternative (M2) phenotype. In addition, pEV pretreatment conditions macrophages to increase bacteria uptake and such macrophages may act as a reservoir for pneumococcal cells by increasing survival of the phagocytosed bacteria. When administered systemically in mice, pEVs induce cytokine release; when immobilized locally, they recruit lymphocytes and macrophages. Taken together, pEVs emerge as critical contributors to inflammatory responses and tissue damage in mammalian hosts.
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9
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Hirschmann S, Gómez-Mejia A, Kohler TP, Voß F, Rohde M, Brendel M, Hammerschmidt S. The Two-Component System 09 of Streptococcus pneumoniae Is Important for Metabolic Fitness and Resistance during Dissemination in the Host. Microorganisms 2021; 9:microorganisms9071365. [PMID: 34201716 PMCID: PMC8306541 DOI: 10.3390/microorganisms9071365] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/12/2021] [Accepted: 06/18/2021] [Indexed: 11/24/2022] Open
Abstract
The two-component regulatory system 09 of Streptococcus pneumoniae has been shown to modulate resistance against oxidative stress as well as capsule expression. These data and the implication of TCS09 in cell wall integrity have been shown for serotype 2 strain D39. Other data have suggested strain-specific regulatory effects of TCS09. Contradictory data are known on the impact of TCS09 on virulence, but all have been explored using only the rr09-mutant. In this study, we have therefore deleted one or both components of the TCS09 (SP_0661 and SP_0662) in serotype 4 S. pneumoniae TIGR4. In vitro growth assays in chemically defined medium (CDM) using sucrose or lactose as a carbon source indicated a delayed growth of nonencapsulated tcs09-mutants, while encapsulated wild-type TIGR4 and tcs09-mutants have reduced growth in CDM with glucose. Using a set of antigen-specific antibodies, immunoblot analysis showed that only the pilus 1 backbone protein RrgB is significantly reduced in TIGR4ΔcpsΔhk09. Electron microscopy, adherence and phagocytosis assays showed no impact of TCS09 on the TIGR4 cell morphology and interaction with host cells. In contrast, in vivo infections and in particular competitive co-infection experiments demonstrated that TCS09 enhances robustness during dissemination in the host by maintaining bacterial fitness.
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Affiliation(s)
- Stephanie Hirschmann
- Center for Functional Genomics of Microbes, Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, 17487 Greifswald, Germany; (S.H.); (A.G.-M.); (T.P.K.); (F.V.); (M.B.)
| | - Alejandro Gómez-Mejia
- Center for Functional Genomics of Microbes, Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, 17487 Greifswald, Germany; (S.H.); (A.G.-M.); (T.P.K.); (F.V.); (M.B.)
| | - Thomas P. Kohler
- Center for Functional Genomics of Microbes, Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, 17487 Greifswald, Germany; (S.H.); (A.G.-M.); (T.P.K.); (F.V.); (M.B.)
| | - Franziska Voß
- Center for Functional Genomics of Microbes, Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, 17487 Greifswald, Germany; (S.H.); (A.G.-M.); (T.P.K.); (F.V.); (M.B.)
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany;
| | - Max Brendel
- Center for Functional Genomics of Microbes, Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, 17487 Greifswald, Germany; (S.H.); (A.G.-M.); (T.P.K.); (F.V.); (M.B.)
| | - Sven Hammerschmidt
- Center for Functional Genomics of Microbes, Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, 17487 Greifswald, Germany; (S.H.); (A.G.-M.); (T.P.K.); (F.V.); (M.B.)
- Correspondence:
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10
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Cole J, Angyal A, Emes RD, Mitchell TJ, Dickman MJ, Dockrell DH. Pneumolysin Is Responsible for Differential Gene Expression and Modifications in the Epigenetic Landscape of Primary Monocyte Derived Macrophages. Front Immunol 2021; 12:573266. [PMID: 34046027 PMCID: PMC8145618 DOI: 10.3389/fimmu.2021.573266] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 04/16/2021] [Indexed: 12/17/2022] Open
Abstract
Epigenetic modifications regulate gene expression in the host response to a diverse range of pathogens. The extent and consequences of epigenetic modification during macrophage responses to Streptococcus pneumoniae, and the role of pneumolysin, a key Streptococcus pneumoniae virulence factor, in influencing these responses, are currently unknown. To investigate this, we infected human monocyte derived macrophages (MDMs) with Streptococcus pneumoniae and addressed whether pneumolysin altered the epigenetic landscape and the associated acute macrophage transcriptional response using a combined transcriptomic and proteomic approach. Transcriptomic analysis identified 503 genes that were differentially expressed in a pneumolysin-dependent manner in these samples. Pathway analysis highlighted the involvement of transcriptional responses to core innate responses to pneumococci including modules associated with metabolic pathways activated in response to infection, oxidative stress responses and NFκB, NOD-like receptor and TNF signalling pathways. Quantitative proteomic analysis confirmed pneumolysin-regulated protein expression, early after bacterial challenge, in representative transcriptional modules associated with innate immune responses. In parallel, quantitative mass spectrometry identified global changes in the relative abundance of histone post translational modifications (PTMs) upon pneumococcal challenge. We identified an increase in the relative abundance of H3K4me1, H4K16ac and a decrease in H3K9me2 and H3K79me2 in a PLY-dependent fashion. We confirmed that pneumolysin blunted early transcriptional responses involving TNF-α and IL-6 expression. Vorinostat, a histone deacetylase inhibitor, similarly downregulated TNF-α production, reprising the pattern observed with pneumolysin. In conclusion, widespread changes in the macrophage transcriptional response are regulated by pneumolysin and are associated with global changes in histone PTMs. Modulating histone PTMs can reverse pneumolysin-associated transcriptional changes influencing innate immune responses, suggesting that epigenetic modification by pneumolysin plays a role in dampening the innate responses to pneumococci.
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Affiliation(s)
- Joby Cole
- Department of Infection, Immunity and Cardiovascular Diseases, University of Sheffield, Sheffield, United Kingdom
- Sheffield Teaching Hospitals NHS FT, Sheffield, United Kingdom
- The Florey Institute, University of Sheffield, Sheffield, United Kingdom
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, United Kingdom
| | - Adrienn Angyal
- Department of Infection, Immunity and Cardiovascular Diseases, University of Sheffield, Sheffield, United Kingdom
| | - Richard D. Emes
- Advanced Data Analysis Centre, University of Nottingham, Nottingham, United Kingdom
- School of Veterinary Medicine and Science University of Nottingham, Nottingham, United Kingdom
| | - Tim John Mitchell
- Institute of Microbiology and Infection, University of Birmingham, Edinburgh, United Kingdom
| | - Mark J. Dickman
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, United Kingdom
| | - David H. Dockrell
- MRC Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
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11
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Tseng YW, Chang CC, Chang YC. Novel Virulence Role of Pneumococcal NanA in Host Inflammation and Cell Death Through the Activation of Inflammasome and the Caspase Pathway. Front Cell Infect Microbiol 2021; 11:613195. [PMID: 33777832 PMCID: PMC7991587 DOI: 10.3389/fcimb.2021.613195] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 02/05/2021] [Indexed: 01/15/2023] Open
Abstract
Streptococcus pneumoniae is one of most deadly Gram-positive bacterium that causes significant mortality and morbidity worldwide. Intense inflammation and cytotoxicity is a hallmark of invasive pneumococcal disease. Pneumococcal NanA has been shown to exaggerate the production of inflammatory cytokines via unmasking of inhibitory Siglec-5 from its sialyl cis-ligands. To further investigate the mechanistic role of NanA and Siglec-5 in pneumococccal diseases, we systemically analyzed genes and signaling pathways differentially regulated in macrophages infected with wild type and NanA-deficient pneumococcus. We found that NanA-mediated desialylation impairs the Siglec-5-TLR-2 interaction and reduces the recruitment of phosphatase SHP-1 to Siglec-5. This dysregulated crosstalk between TLR-2 and inhibitory Siglec-5 exaggerated multiple inflammatory and death signaling pathways and consequently caused excessive inflammation and cytotoxicity in the infected macrophage. Collectively, our results reveal a novel virulence role of NanA in pneumococcal pathogenesis and suggest that targeting NanA activity may ameliorate the pneumococcus-mediated inflammation and cytotoxicity in severe invasive pneumococcal diseases.
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Affiliation(s)
- Yu-Wen Tseng
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chun-Chi Chang
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yung-Chi Chang
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
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12
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Role of astroglial Connexin 43 in pneumolysin cytotoxicity and during pneumococcal meningitis. PLoS Pathog 2020; 16:e1009152. [PMID: 33370401 PMCID: PMC7793270 DOI: 10.1371/journal.ppat.1009152] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 01/08/2021] [Accepted: 11/11/2020] [Indexed: 12/19/2022] Open
Abstract
Streptococcus pneumoniae or pneumococcus (PN) is a major causative agent of bacterial meningitis with high mortality in young infants and elderly people worldwide. The mechanism underlying PN crossing of the blood brain barrier (BBB) and specifically, the role of non-endothelial cells of the neurovascular unit that control the BBB function, remains poorly understood. Here, we show that the astroglial connexin 43 (aCx43), a major gap junctional component expressed in astrocytes, plays a predominant role during PN meningitis. Following intravenous PN challenge, mice deficient for aCx43 developed milder symptoms and showed severely reduced bacterial counts in the brain. Immunofluorescence analysis of brain slices indicated that PN induces the aCx43–dependent destruction of the network of glial fibrillary acid protein (GFAP), an intermediate filament protein specifically expressed in astrocytes and up-regulated in response to brain injury. PN also induced nuclear shrinkage in astrocytes associated with the loss of BBB integrity, bacterial translocation across endothelial vessels and replication in the brain cortex. We found that aCx4-dependent astrocyte damages could be recapitulated using in vitro cultured cells upon challenge with wild-type PN but not with a ply mutant deficient for the pore-forming toxin pneumolysin (Ply). Consistently, we showed that purified Ply requires Cx43 to promote host cell plasma membrane permeabilization in a process involving the Cx43-dependent release of extracellular ATP and prolonged increase of cytosolic Ca2+ in host cells. These results point to a critical role for astrocytes during PN meningitis and suggest that the cytolytic activity of the major virulence factor Ply at concentrations relevant to bacterial infection requires co-opting of connexin plasma membrane channels. The role of non-endothelial cells constituting the neurovascular unit during infectious meningitis is poorly appreciated despite their key regulatory functions on the blood-brain barrier integrity. Here, we show that Streptococcus pneumoniae or pneumococcus, a major causative agent of bacterial meningitis, targets astroglial cells to translocate across brain endothelial vessels. We found that astroglial connexin 43, a gap junctional component, played a major role during PN meningitis in mice. PN translocation and replication in the brain cortex were associated with connexin-dependent fragmentation of astrocytic the GFAP network, a process associated with brain injury. These findings were recapitulated and extended in vitro using cultured primary astrocytes and the major PN virulence determinant Pneumolysin. Ply-mediated cytotoxicity was linked to Ca2+ increase and required aCx43, arguing against a direct toxin activity. The results reveal a key role for astroglial signaling during PN crossing of the BBB and shed light on the mechanism of Ply-mediated cytotoxicity during meningitis.
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Macrophage LC3-associated phagocytosis is an immune defense against Streptococcus pneumoniae that diminishes with host aging. Proc Natl Acad Sci U S A 2020; 117:33561-33569. [PMID: 33376222 PMCID: PMC7776987 DOI: 10.1073/pnas.2015368117] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Streptococcus pneumoniae is a leading cause of pneumonia and invasive disease, particularly, in the elderly. S. pneumoniae lung infection of aged mice is associated with high bacterial burdens and detrimental inflammatory responses. Macrophages can clear microorganisms and modulate inflammation through two distinct lysosomal trafficking pathways that involve 1A/1B-light chain 3 (LC3)-marked organelles, canonical autophagy, and LC3-associated phagocytosis (LAP). The S. pneumoniae pore-forming toxin pneumolysin (PLY) triggers an autophagic response in nonphagocytic cells, but the role of LAP in macrophage defense against S. pneumoniae or in age-related susceptibility to infection is unexplored. We found that infection of murine bone-marrow-derived macrophages (BMDMs) by PLY-producing S. pneumoniae triggered Atg5- and Atg7-dependent recruitment of LC3 to S. pneumoniae-containing vesicles. The association of LC3 with S. pneumoniae-containing phagosomes required components specific for LAP, such as Rubicon and the NADPH oxidase, but not factors, such as Ulk1, FIP200, or Atg14, required specifically for canonical autophagy. In addition, S. pneumoniae was sequestered within single-membrane compartments indicative of LAP. Importantly, compared to BMDMs from young (2-mo-old) mice, BMDMs from aged (20- to 22-mo-old) mice infected with S. pneumoniae were not only deficient in LAP and bacterial killing, but also produced higher levels of proinflammatory cytokines. Inhibition of LAP enhanced S. pneumoniae survival and cytokine responses in BMDMs from young but not aged mice. Thus, LAP is an important innate immune defense employed by BMDMs to control S. pneumoniae infection and concomitant inflammation, one that diminishes with age and may contribute to age-related susceptibility to this important pathogen.
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14
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Nagakannan P, Tabeshmehr P, Eftekharpour E. Oxidative damage of lysosomes in regulated cell death systems: Pathophysiology and pharmacologic interventions. Free Radic Biol Med 2020; 157:94-127. [PMID: 32259579 DOI: 10.1016/j.freeradbiomed.2020.04.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 03/31/2020] [Accepted: 04/01/2020] [Indexed: 12/16/2022]
Abstract
Lysosomes are small specialized organelles containing a variety of different hydrolase enzymes that are responsible for degradation of all macromolecules, entering the cells through the endosomal system or originated from the internal sources. This allows for transport and recycling of nutrients and internalization of surface proteins for antigen presentation as well as maintaining cellular homeostasis. Lysosomes are also important storage compartments for metal ions and nutrients. The integrity of lysosomal membrane is central to maintaining their normal function, but like other cellular membranes, lysosomal membrane is subject to damage mediated by reactive oxygen species. This results in spillage of lysosomal enzymes into the cytoplasm, leading to proteolytic damage to cellular systems and organelles. Several forms of lysosomal dependent cell death have been identified in diseases. Examination of these events are important for finding treatment strategies relevant to cancer or neurodegenerative diseases as well as autoimmune deficiencies. In this review, we have examined the current literature on involvement of lysosomes in induction of programed cell death and have provided an extensive list of therapeutic approaches that can modulate cell death. Exploitation of these mechanisms can lead to novel therapies for cancer and neurodegenerative diseases.
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Affiliation(s)
- Pandian Nagakannan
- Regenerative Medicine Program and Spinal Cord Research Centre, Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Parisa Tabeshmehr
- Regenerative Medicine Program and Spinal Cord Research Centre, Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Eftekhar Eftekharpour
- Regenerative Medicine Program and Spinal Cord Research Centre, Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada.
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15
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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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16
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Watson K, Russell CD, Baillie JK, Dhaliwal K, Fitzgerald JR, Mitchell TJ, Simpson AJ, Renshaw SA, Dockrell DH. Developing Novel Host-Based Therapies Targeting Microbicidal Responses in Macrophages and Neutrophils to Combat Bacterial Antimicrobial Resistance. Front Immunol 2020; 11:786. [PMID: 32582139 PMCID: PMC7289984 DOI: 10.3389/fimmu.2020.00786] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 04/07/2020] [Indexed: 12/11/2022] Open
Abstract
Antimicrobial therapy has provided the main component of chemotherapy against bacterial pathogens. The effectiveness of this strategy has, however, been increasingly challenged by the emergence of antimicrobial resistance which now threatens the sustained utility of this approach. Humans and animals are constantly exposed to bacteria and have developed effective strategies to control pathogens involving innate and adaptive immune responses. Impaired pathogen handling by the innate immune system is a key determinant of susceptibility to bacterial infection. However, the essential components of this response, specifically those which are amenable to re-calibration to improve host defense, remain elusive despite extensive research. We provide a mini-review focusing on therapeutic targeting of microbicidal responses in macrophages and neutrophils to de-stress reliance on antimicrobial therapy. We highlight pre-clinical and clinical data pointing toward potential targets and therapies. We suggest that developing focused host-directed therapeutic strategies to enhance "pauci-inflammatory" microbial killing in myeloid phagocytes that maximizes pathogen clearance while minimizing the harmful consequences of the inflammatory response merits particular attention. We also suggest the importance of One Health approaches in developing host-based approaches through model development and comparative medicine in informing our understanding of how to deliver this strategy.
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Affiliation(s)
- Katie Watson
- Department of Infection Medicine, University of Edinburgh, Edinburgh, United Kingdom.,Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Clark D Russell
- Department of Infection Medicine, University of Edinburgh, Edinburgh, United Kingdom.,Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom.,Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - J Kenneth Baillie
- Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Kev Dhaliwal
- Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
| | - J Ross Fitzgerald
- Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Timothy J Mitchell
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - A John Simpson
- Institute of Cellular Medicine, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Stephen A Renshaw
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom
| | - David H Dockrell
- Department of Infection Medicine, University of Edinburgh, Edinburgh, United Kingdom.,Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
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17
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Preston JA, Bewley MA, Marriott HM, McGarry Houghton A, Mohasin M, Jubrail J, Morris L, Stephenson YL, Cross S, Greaves DR, Craig RW, van Rooijen N, Bingle CD, Read RC, Mitchell TJ, Whyte MKB, Shapiro SD, Dockrell DH. Alveolar Macrophage Apoptosis-associated Bacterial Killing Helps Prevent Murine Pneumonia. Am J Respir Crit Care Med 2020; 200:84-97. [PMID: 30649895 DOI: 10.1164/rccm.201804-0646oc] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Rationale: Antimicrobial resistance challenges therapy of pneumonia. Enhancing macrophage microbicidal responses would combat this problem but is limited by our understanding of how alveolar macrophages (AMs) kill bacteria. Objectives: To define the role and mechanism of AM apoptosis-associated bacterial killing in the lung. Methods: We generated a unique CD68.hMcl-1 transgenic mouse with macrophage-specific overexpression of the human antiapoptotic Mcl-1 protein, a factor upregulated in AMs from patients at increased risk of community-acquired pneumonia, to address the requirement for apoptosis-associated killing. Measurements and Main Results: Wild-type and transgenic macrophages demonstrated comparable ingestion and initial phagolysosomal killing of bacteria. Continued ingestion (for ≥12 h) overwhelmed initial killing, and a second, late-phase microbicidal response killed viable bacteria in wild-type macrophages, but this response was blunted in CD68.hMcl-1 transgenic macrophages. The late phase of bacterial killing required both caspase-induced generation of mitochondrial reactive oxygen species and nitric oxide, the peak generation of which coincided with the late phase of killing. The CD68.hMcl-1 transgene prevented mitochondrial reactive oxygen species but not nitric oxide generation. Apoptosis-associated killing enhanced pulmonary clearance of Streptococcus pneumoniae and Haemophilus influenzae in wild-type mice but not CD68.hMcl-1 transgenic mice. Bacterial clearance was enhanced in vivo in CD68.hMcl-1 transgenic mice by reconstitution of apoptosis with BH3 mimetics or clodronate-encapsulated liposomes. Apoptosis-associated killing was not activated during Staphylococcus aureus lung infection. Conclusions: Mcl-1 upregulation prevents macrophage apoptosis-associated killing and establishes that apoptosis-associated killing is required to allow AMs to clear ingested bacteria. Engagement of macrophage apoptosis should be investigated as a novel, host-based antimicrobial strategy.
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Affiliation(s)
- Julie A Preston
- 1 The Florey Institute for Host-Pathogen Interactions and.,2 Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom
| | - Martin A Bewley
- 1 The Florey Institute for Host-Pathogen Interactions and.,2 Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom
| | - Helen M Marriott
- 1 The Florey Institute for Host-Pathogen Interactions and.,2 Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom
| | - A McGarry Houghton
- 3 Clinical Research Division, Fred Hutchinson Cancer Research Center, and.,4 Division of Pulmonary and Critical Care Medicine, University of Washington, Seattle, Washington
| | - Mohammed Mohasin
- 5 Department of Biochemistry and Molecular Biology, University of Dhaka, Dhaka, Bangladesh
| | | | - Lucy Morris
- 1 The Florey Institute for Host-Pathogen Interactions and.,2 Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom
| | - Yvonne L Stephenson
- 1 The Florey Institute for Host-Pathogen Interactions and.,2 Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom
| | - Simon Cross
- 1 The Florey Institute for Host-Pathogen Interactions and.,2 Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom.,7 Sheffield Teaching Hospitals, Sheffield, United Kingdom
| | - David R Greaves
- 8 Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Ruth W Craig
- 9 Department of Pharmacology and Toxicology, Geissel School of Medicine at Dartmouth, Hanover, New Hampshire
| | - Nico van Rooijen
- 10 Department of Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam, the Netherlands
| | - Colin D Bingle
- 1 The Florey Institute for Host-Pathogen Interactions and.,2 Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom
| | - Robert C Read
- 11 University of Southampton Medical School, Southampton, United Kingdom.,12 National Institute for Health Research Southampton Biomedical Research Centre, Southampton, United Kingdom
| | - Timothy J Mitchell
- 13 Institute of Microbiology and Infection, School of Immunity and Infection, University of Birmingham, Birmingham, United Kingdom; and
| | - Moira K B Whyte
- 6 MRC Centre for Inflammation Research.,14 Department of Respiratory Medicine, and
| | - Steven D Shapiro
- 15 Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - David H Dockrell
- 6 MRC Centre for Inflammation Research.,16 Infection Medicine, University of Edinburgh, Edinburgh, United Kingdom
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18
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Opening the OPK Assay Gatekeeper: Harnessing Multi-Modal Protection by Pneumococcal Vaccines. Pathogens 2019; 8:pathogens8040203. [PMID: 31652741 PMCID: PMC6963391 DOI: 10.3390/pathogens8040203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 10/14/2019] [Accepted: 10/21/2019] [Indexed: 11/16/2022] Open
Abstract
Pneumococcal vaccine development is driven by the achievement of high activity in a single gatekeeper assay: the bacterial opsonophagocytic killing (OPK) assay. New evidence challenges the dogma that anti-capsular antibodies have only a single function that predicts success. The emerging concept of multi-modal protection presents an array of questions that are fundamental to adopting a new vaccine design process. If antibodies have hidden non-opsonic functions that are protective, should these be optimized for better vaccines? What would protein antigens add to protective activity? Are cellular immune functions additive to antibodies for success? Do different organs benefit from different modes of protection? Can vaccine activities beyond OPK protect the immunocompromised host? This commentary raises these issues at a time when capsule-only OPK assay-based vaccines are increasingly seen as a limiting strategy.
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19
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Domain 4 of pneumolysin from Streptococcus pneumoniae is a multifunctional domain contributing TLR4 activating and hemolytic activity. Biochem Biophys Res Commun 2019; 517:596-602. [PMID: 31395343 DOI: 10.1016/j.bbrc.2019.07.063] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 07/18/2019] [Indexed: 11/21/2022]
Abstract
The pneumolysin (Ply) protein of Streptococcus pneumoniae is composed of four domains and possesses several different but related activities. In this study, recombinant Ply and two truncated forms, Ply domain 1-3 and Ply domain 4 (rPly4), were expressed and characterized regarding their participation in apoptosis, the stimulation of cytokine production, hemolytic activity and virulence. rPly4 activated murine bone marrow-derived dendritic cells in a Toll-like receptor (TLR) 4-dependent manner. The rPly4 alone was able to produce hemolytic activity at high concertation and penetrate the lipid bilayer. We further demonstrated that domain 4 of Ply involved in the virulence of the bacteria in mouse model. In the absence of apoptotic activity, the virulence level caused by rPly4 was similar to that of full length Ply. Our data suggested that domain 4 of Ply alone with TLR4 agonist and hemolytic activity may play roles in virulence of Streptococcus pneumoniae.
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20
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Abstract
Community-acquired pneumonia (CAP) is a leading cause of morbidity and mortality worldwide. Despite broad literature including basic and translational scientific studies, many gaps in our understanding of host-pathogen interactions remain. In this review, pathogen virulence factors that drive lung infection and injury are discussed in relation to their associated host immune pathways. CAP epidemiology is considered, with a focus on Staphylococcus aureus and Streptococcus pneumoniae as primary pathogens. Bacterial factors involved in nasal colonization and subsequent virulence are illuminated. A particular emphasis is placed on bacterial pore-forming toxins, host cell death, and inflammasome activation. Identified host-pathogen interactions are then examined by linking pathogen factors to aberrant host response pathways in the context of acute lung injury in both primary and secondary infection. While much is known regarding bacterial virulence and host immune responses, CAP management is still limited to mostly supportive care. It is likely that improvements in therapy will be derived from combinatorial targeting of both pathogen virulence factors and host immunomodulation.
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21
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Wang F, Gómez-Sintes R, Boya P. Lysosomal membrane permeabilization and cell death. Traffic 2018; 19:918-931. [DOI: 10.1111/tra.12613] [Citation(s) in RCA: 198] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Revised: 08/15/2018] [Accepted: 08/15/2018] [Indexed: 12/12/2022]
Affiliation(s)
- Fengjuan Wang
- Unit Biotechnology and Cell Signaling/Laboratory of Excellence Medalis, CNRS/Université de Strasbourg; Illkirch France
| | - Raquel Gómez-Sintes
- Departament of Cellular and Molecular Biology; Centro de Investigaciones Biológicas, CSIC; Madrid Spain
| | - Patricia Boya
- Departament of Cellular and Molecular Biology; Centro de Investigaciones Biológicas, CSIC; Madrid Spain
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22
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De Leon-Rodriguez CM, Rossi DCP, Fu MS, Dragotakes Q, Coelho C, Guerrero Ros I, Caballero B, Nolan SJ, Casadevall A. The Outcome of the Cryptococcus neoformans-Macrophage Interaction Depends on Phagolysosomal Membrane Integrity. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2018; 201:583-603. [PMID: 29858266 PMCID: PMC6245949 DOI: 10.4049/jimmunol.1700958] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 05/08/2018] [Indexed: 01/15/2023]
Abstract
Cryptococcus neoformans is a fungal pathogen with worldwide distribution. C. neoformans resides within mature phagolysosomes where it often evades killing and replicates. C. neoformans induces phagolysosomal membrane permeabilization (PMP), but the mechanism for this phenomenon and its consequences for macrophage viability are unknown. In this study, we used flow cytometry methodology in combination with cell viability markers and LysoTracker to measure PMP in J774.16 and murine bone marrow-derived macrophages infected with C. neoformans Our results showed that cells manifesting PMP were positive for apoptotic markers, indicating an association between PMP and apoptosis. We investigated the role of phospholipase B1 in C. neoformans induction of PMP. Macrophages infected with a C. neoformans Δplb1 mutant had reduced PMP compared with those infected with wild-type and phospholipase B1-complemented strains, suggesting a mechanism of action for this virulence factor. Capsular enlargement inside macrophages was identified as an additional likely mechanism for phagolysosomal membrane damage. Macrophages undergoing apoptosis did not maintain an acidic phagolysosomal pH. Induction of PMP with ciprofloxacin enhanced macrophages to trigger lytic exocytosis whereas nonlytic exocytosis was common in those without PMP. Our results suggest that modulation of PMP is a critical event in determining the outcome of C. neoformans-macrophage interaction.
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Affiliation(s)
| | - Diego C P Rossi
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205
| | - Man Shun Fu
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205
| | - Quigly Dragotakes
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205
| | - Carolina Coelho
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205
| | - Ignacio Guerrero Ros
- Department of Pathology, Albert Einstein College of Medicine, New York, NY 10461; and
| | - Benjamin Caballero
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, New York, NY 10461
| | - Sabrina J Nolan
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205
| | - Arturo Casadevall
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY 10461;
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205
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23
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Santos G, Lai X, Eberhardt M, Vera J. Bacterial Adherence and Dwelling Probability: Two Drivers of Early Alveolar Infection by Streptococcus pneumoniae Identified in Multi-Level Mathematical Modeling. Front Cell Infect Microbiol 2018; 8:159. [PMID: 29868515 PMCID: PMC5962665 DOI: 10.3389/fcimb.2018.00159] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 04/25/2018] [Indexed: 01/31/2023] Open
Abstract
Pneumococcal infection is the most frequent cause of pneumonia, and one of the most prevalent diseases worldwide. The population groups at high risk of death from bacterial pneumonia are infants, elderly and immunosuppressed people. These groups are more vulnerable because they have immature or impaired immune systems, the efficacy of their response to vaccines is lower, and antibiotic treatment often does not take place until the inflammatory response triggered is already overwhelming. The immune response to bacterial lung infections involves dynamic interactions between several types of cells whose activation is driven by intracellular molecular networks. A feasible approach to the integration of knowledge and data linking tissue, cellular and intracellular events and the construction of hypotheses in this area is the use of mathematical modeling. For this paper, we used a multi-level computational model to analyse the role of cellular and molecular interactions during the first 10 h after alveolar invasion of Streptococcus pneumoniae bacteria. By “multi-level” we mean that we simulated the interplay between different temporal and spatial scales in a single computational model. In this instance, we included the intracellular scale of processes driving lung epithelial cell activation together with the scale of cell-to-cell interactions at the alveolar tissue. In our analysis, we combined systematic model simulations with logistic regression analysis and decision trees to find genotypic-phenotypic signatures that explain differences in bacteria strain infectivity. According to our simulations, pneumococci benefit from a high dwelling probability and a high proliferation rate during the first stages of infection. In addition to this, the model predicts that during the very early phases of infection the bacterial capsule could be an impediment to the establishment of the alveolar infection because it impairs bacterial colonization.
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Affiliation(s)
- Guido Santos
- Laboratory of Systems Tumor Immunology, Department of Dermatology, Universitätsklinikum Erlangen and Faculty of Medicine, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Xin Lai
- Laboratory of Systems Tumor Immunology, Department of Dermatology, Universitätsklinikum Erlangen and Faculty of Medicine, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Martin Eberhardt
- Laboratory of Systems Tumor Immunology, Department of Dermatology, Universitätsklinikum Erlangen and Faculty of Medicine, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Julio Vera
- Laboratory of Systems Tumor Immunology, Department of Dermatology, Universitätsklinikum Erlangen and Faculty of Medicine, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
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24
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Ercoli G, Fernandes VE, Chung WY, Wanford JJ, Thomson S, Bayliss CD, Straatman K, Crocker PR, Dennison A, Martinez-Pomares L, Andrew PW, Moxon ER, Oggioni MR. Intracellular replication of Streptococcus pneumoniae inside splenic macrophages serves as a reservoir for septicaemia. Nat Microbiol 2018; 3:600-610. [PMID: 29662129 PMCID: PMC6207342 DOI: 10.1038/s41564-018-0147-1] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 03/08/2018] [Indexed: 01/21/2023]
Abstract
Bacterial septicaemia is a major cause of mortality, but its pathogenesis remains poorly understood. In experimental pneumococcal murine intravenous infection, an initial reduction of bacteria in the blood is followed hours later by a fatal septicaemia. These events represent a population bottleneck driven by efficient clearance of pneumococci by splenic macrophages and neutrophils, but as we show in this study, accompanied by occasional intracellular replication of bacteria that are taken up by a subset of CD169+ splenic macrophages. In this model, proliferation of these sequestered bacteria provides a reservoir for dissemination of pneumococci into the bloodstream, as demonstrated by its prevention using an anti-CD169 monoclonal antibody treatment. Intracellular replication of pneumococci within CD169+ splenic macrophages was also observed in an ex vivo porcine spleen, where the microanatomy is comparable with humans. We also showed that macrolides, which effectively penetrate macrophages, prevented septicaemia, whereas beta-lactams, with inefficient intracellular penetration, failed to prevent dissemination to the blood. Our findings define a shift in our understanding of the pneumococcus from an exclusively extracellular pathogen to one with an intracellular phase. These findings open the door to the development of treatments that target this early, previously unrecognized intracellular phase of bacterial sepsis.
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Affiliation(s)
- Giuseppe Ercoli
- Department of Genetics and Genome Biology, University of Leicester, Leicester, UK
| | - Vitor E Fernandes
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - Wen Y Chung
- Hepato-Pancreato-Biliary Unit, Leicester General Hospital, University of Hospitals of Leicester, NHS Trust, Leicester, UK
| | - Joseph J Wanford
- Department of Genetics and Genome Biology, University of Leicester, Leicester, UK
| | - Sarah Thomson
- Division of Cell Signalling and Immunology, School of Life Sciences, University of Dundee, Dundee, UK
| | | | - Kornelis Straatman
- Centre for Core Biotechnology Services, University of Leicester, Leicester, UK
| | - Paul R Crocker
- Division of Cell Signalling and Immunology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Ashley Dennison
- Hepato-Pancreato-Biliary Unit, Leicester General Hospital, University of Hospitals of Leicester, NHS Trust, Leicester, UK
| | - Luisa Martinez-Pomares
- School of Life Sciences, Faculty of Medicine & Health Sciences, University of Nottingham, Nottingham, UK
| | - Peter W Andrew
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | | | - Marco R Oggioni
- Department of Genetics and Genome Biology, University of Leicester, Leicester, UK.
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25
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Lysosomal membrane permeabilization as a cell death mechanism in cancer cells. Biochem Soc Trans 2018; 46:207-215. [DOI: 10.1042/bst20170130] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2017] [Revised: 01/12/2018] [Accepted: 01/15/2018] [Indexed: 12/11/2022]
Abstract
Lysosomes are acidic organelles that contain hydrolytic enzymes that mediate the intracellular degradation of macromolecules. Damage of these organelles often results in lysosomal membrane permeabilization (LMP) and the release into the cytoplasm of the soluble lysosomal contents, which include proteolytic enzymes of the cathepsin family. This, in turn, activates several intracellular cascades that promote a type of regulated cell death, called lysosome-dependent cell death (LDCD). LDCD can be inhibited by pharmacological or genetic blockade of cathepsin activity, or by protecting the lysosomal membrane, thereby stabilizing the organelle. Lysosomal alterations are common in cancer cells and may increase the sensitivity of these cells to agents that promote LMP. In this review, we summarize recent findings supporting the use of LDCD as a means of killing cancer cells.
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Cell Invasion and Pyruvate Oxidase-Derived H 2O 2 Are Critical for Streptococcus pneumoniae-Mediated Cardiomyocyte Killing. Infect Immun 2017; 86:IAI.00569-17. [PMID: 29061707 DOI: 10.1128/iai.00569-17] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 10/17/2017] [Indexed: 01/19/2023] Open
Abstract
Streptococcus pneumoniae (the pneumococcus) is the leading cause of community-acquired pneumonia and is now recognized to be a direct contributor to adverse acute cardiac events. During invasive pneumococcal disease, S. pneumoniae can gain access to the myocardium, kill cardiomyocytes, and form bacterium-filled "microlesions" causing considerable acute and long-lasting cardiac damage. While the molecular mechanisms responsible for bacterial translocation into the heart have been elucidated, the initial interactions of heart-invaded S. pneumoniae with cardiomyocytes remain unclear. In this study, we used a model of low multiplicity of S. pneumoniae infection with HL-1 mouse cardiomyocytes to investigate these early events. Using adhesion/invasion assays and immunofluorescent and transmission electron microscopy, we showed that S. pneumoniae rapidly adhered to and invaded cardiomyocytes. What is more, pneumococci existed as intravacuolar bacteria or escaped into the cytoplasm. Pulse-chase assays with BrdU confirmed intracellular replication of pneumococci within HL-1 cells. Using endocytosis inhibitors, bacterial isogenic mutants, and neutralizing antibodies against host proteins recognized by S. pneumoniae adhesins, we showed that S. pneumoniae uptake by cardiomyocytes is not through the well-studied canonical interactions identified for vascular endothelial cells. Indeed, S. pneumoniae invasion of HL-1 cells occurred through clathrin-mediated endocytosis (CME) and independently of choline binding protein A (CbpA)/laminin receptor, CbpA/polymeric immunoglobulin receptor, or cell wall phosphorylcholine/platelet-activating factor receptor. Subsequently, we determined that pneumolysin and streptococcal pyruvate oxidase-derived H2O2 production were required for cardiomyocyte killing. Finally, we showed that this cytotoxicity could be abrogated using CME inhibitors or antioxidants, attesting to intracellular replication of S. pneumoniae as a key first step in pneumococcal pathogenesis within the heart.
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Zou J, Zhou L, Hu C, Jing P, Guo X, Liu S, Lei Y, Yang S, Deng J, Zhang H. IL-8 and IP-10 expression from human bronchial epithelial cells BEAS-2B are promoted by Streptococcus pneumoniae endopeptidase O (PepO). BMC Microbiol 2017; 17:187. [PMID: 28836948 PMCID: PMC5571634 DOI: 10.1186/s12866-017-1081-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 07/31/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The bronchial epithelium serves as the first defendant line of host against respiratory inhaled pathogens, mainly through releasing chemokines (e.g. interleukin-8 (IL-8), interferon-induced protein 10 (IP-10) etc.) responsible for neutrophil or lymphocyte recruitment to promote the clearance of inhaled pathogens including Streptococcus pneumoniae (S. pneumoniae). Previous studies have shown that IL-8 expression is induced by pneumococcal virulence factors (e.g. pneumolysin, peptidoglycan-polysaccharides, pneumococcal surface protein A (PspA) etc.), which contributes to the pathogenesis of pneumonia. Whether other pneumococcal virulence factors are involved in inducing chemokines expression in epithelium is still unknown. RESULTS We studied the effect of PepO, a widely expressed and newly discovered pneumococcal virulence protein, on the release of proinflammatory cytokines, IL-8 and IP-10, from human bronchial epithelial cell line BEAS-2B and identified the relevant signaling pathways. Incubation of BEAS-2B with PepO resulted in increased synthesis and release of IL-8 and IP-10 in a dose and time independent manner. We also detected the increased and sustained expression of TLR2 and TLR4 transcripts in BEAS-2B stimulated by PepO. PepO activation leaded to the phosphorylation of MAPKs, Akt and p65. Pharmacologic inhibitors of MAPKs, PI3K and IκB-α phosphorylation attenuated IL-8 release, while IP-10 production was just suppressed by inhibitors of IκB-α phosphorylation, PI3K and P38 MAPK. CONCLUSION These results suggest that PepO enhances IL-8 and IP-10 production in BEAS-2B in a MAPKs-PI3K/Akt-p65 dependent manner, which may play critical roles in the pathogenesis of pneumonia.
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Affiliation(s)
- Jiaqiong Zou
- Department of Laboratory Medicine, The Affiliated Hospital of North Sichuan Medical College, 63 Wenhua Road, Shunqing District, Nanchong, Sichuan, 637000, China.,Department of Laboratory Medicine, North Sichuan Medical College; Translational Medicine Research Center, North Sichuan Medical College, Nanchong, Sichuan, China
| | - Long Zhou
- Department of Laboratory Medicine, Chongqing Three Gorges Central Hospital, Wanzhou, Chongqing, 404100, China
| | - Chunlan Hu
- Department of General Medicine, Chongqing Three Gorges Central Hospital, Wanzhou, Chongqing, 404100, China
| | - Peng Jing
- Department of Laboratory Medicine, The Affiliated Hospital of North Sichuan Medical College, 63 Wenhua Road, Shunqing District, Nanchong, Sichuan, 637000, China.,Department of Laboratory Medicine, North Sichuan Medical College; Translational Medicine Research Center, North Sichuan Medical College, Nanchong, Sichuan, China
| | - Xiaolan Guo
- Department of Pediatric Surgery, The Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan, China
| | - Sulan Liu
- Department of Laboratory Medicine, The Affiliated Hospital of North Sichuan Medical College, 63 Wenhua Road, Shunqing District, Nanchong, Sichuan, 637000, China.,Department of Laboratory Medicine, North Sichuan Medical College; Translational Medicine Research Center, North Sichuan Medical College, Nanchong, Sichuan, China
| | - Yan Lei
- Department of Laboratory Medicine, The Affiliated Hospital of North Sichuan Medical College, 63 Wenhua Road, Shunqing District, Nanchong, Sichuan, 637000, China.,Department of Laboratory Medicine, North Sichuan Medical College; Translational Medicine Research Center, North Sichuan Medical College, Nanchong, Sichuan, China
| | - Shangyu Yang
- Department of Laboratory Medicine, The Affiliated Hospital of North Sichuan Medical College, 63 Wenhua Road, Shunqing District, Nanchong, Sichuan, 637000, China.,Department of Laboratory Medicine, North Sichuan Medical College; Translational Medicine Research Center, North Sichuan Medical College, Nanchong, Sichuan, China
| | - Jiankang Deng
- Department of Laboratory Medicine, The Affiliated Hospital of North Sichuan Medical College, 63 Wenhua Road, Shunqing District, Nanchong, Sichuan, 637000, China. .,Department of Laboratory Medicine, North Sichuan Medical College; Translational Medicine Research Center, North Sichuan Medical College, Nanchong, Sichuan, China.
| | - Hong Zhang
- Department of Laboratory Medicine, The Affiliated Hospital of North Sichuan Medical College, 63 Wenhua Road, Shunqing District, Nanchong, Sichuan, 637000, China. .,Department of Laboratory Medicine, North Sichuan Medical College; Translational Medicine Research Center, North Sichuan Medical College, Nanchong, Sichuan, China.
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Rolhion N, Cossart P. How the study of Listeria monocytogenes has led to new concepts in biology. Future Microbiol 2017; 12:621-638. [PMID: 28604108 DOI: 10.2217/fmb-2016-0221] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The opportunistic intracellular bacterial pathogen Listeria monocytogenes has in 30 years emerged as an exceptional bacterial model system in infection biology. Research on this bacterium has provided considerable insight into how pathogenic bacteria adapt to mammalian hosts, invade eukaryotic cells, move intracellularly, interfere with host cell functions and disseminate within tissues. It also contributed to unveil features of normal host cell pathways and unsuspected functions of previously known cellular proteins. This review provides an updated overview of our knowledge on this pathogen. In many examples, findings on L. monocytogenes provided the basis for new concepts in bacterial regulation, cell biology and infection processes.
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Affiliation(s)
- Nathalie Rolhion
- Département de Biologie Cellulaire et Infection, Unité des Interactions Bactéries-Cellules, Institut Pasteur, F-75015 Paris, France.,INSERM, U604, F-75015 Paris, France.,INRA, Unité sous-contrat 2020, F-75015 Paris, France
| | - Pascale Cossart
- Département de Biologie Cellulaire et Infection, Unité des Interactions Bactéries-Cellules, Institut Pasteur, F-75015 Paris, France.,INSERM, U604, F-75015 Paris, France.,INRA, Unité sous-contrat 2020, F-75015 Paris, France
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29
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Kwon IS, Kim J, Rhee DK, Kim BO, Pyo S. Pneumolysin induces cellular senescence by increasing ROS production and activation of MAPK/NF-κB signal pathway in glial cells. Toxicon 2017; 129:100-112. [DOI: 10.1016/j.toxicon.2017.02.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 02/15/2017] [Accepted: 02/17/2017] [Indexed: 02/01/2023]
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30
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Anderson R, Feldman C. Pneumolysin as a potential therapeutic target in severe pneumococcal disease. J Infect 2017; 74:527-544. [PMID: 28322888 DOI: 10.1016/j.jinf.2017.03.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 03/09/2017] [Accepted: 03/11/2017] [Indexed: 12/13/2022]
Abstract
Acute pulmonary and cardiac injury remain significant causes of morbidity and mortality in those afflicted with severe pneumococcal disease, with the risk for early mortality often persisting several years beyond clinical recovery. Although remaining to be firmly established in the clinical setting, a considerable body of evidence, mostly derived from murine models of experimental infection, has implicated the pneumococcal, cholesterol-binding, pore-forming toxin, pneumolysin (Ply), in the pathogenesis of lung and myocardial dysfunction. Topics covered in this review include the burden of pneumococcal disease, risk factors, virulence determinants of the pneumococcus, complications of severe disease, antibiotic and adjuvant therapies, as well as the structure of Ply and the role of the toxin in disease pathogenesis. Given the increasing recognition of the clinical potential of Ply-neutralisation strategies, the remaining sections of the review are focused on updates of the types, benefits and limitations of currently available therapies which may attenuate, directly and/or indirectly, the injurious actions of Ply. These include recently described experimental therapies such as various phytochemicals and lipids, and a second group of more conventional agents the members of which remain the subject of ongoing clinical evaluation. This latter group, which is covered more extensively, encompasses macrolides, statins, corticosteroids, and platelet-targeted therapies, particularly aspirin.
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Affiliation(s)
- Ronald Anderson
- Department of Immunology and Institute of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa.
| | - Charles Feldman
- Division of Pulmonology, Department of Internal Medicine, Charlotte Maxeke Johannesburg Academic Hospital and Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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31
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Gómez-Sintes R, Ledesma MD, Boya P. Lysosomal cell death mechanisms in aging. Ageing Res Rev 2016; 32:150-168. [PMID: 26947122 DOI: 10.1016/j.arr.2016.02.009] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Revised: 02/22/2016] [Accepted: 02/29/2016] [Indexed: 12/14/2022]
Abstract
Lysosomes are degradative organelles essential for cell homeostasis that regulate a variety of processes, from calcium signaling and nutrient responses to autophagic degradation of intracellular components. Lysosomal cell death is mediated by the lethal effects of cathepsins, which are released into the cytoplasm following lysosomal damage. This process of lysosomal membrane permeabilization and cathepsin release is observed in several physiopathological conditions and plays a role in tissue remodeling, the immune response to intracellular pathogens and neurodegenerative diseases. Many evidences indicate that aging strongly influences lysosomal activity by altering the physical and chemical properties of these organelles, rendering them more sensitive to stress. In this review we focus on how aging alters lysosomal function and increases cell sensitivity to lysosomal membrane permeabilization and lysosomal cell death, both in physiological conditions and age-related pathologies.
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Affiliation(s)
- Raquel Gómez-Sintes
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biologicas, CIB-CSIC, C/Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - María Dolores Ledesma
- Department of Molecular Neurobiology, Centro Biologia Molecular Severo Ochoa, CSIC-UAM, C/Nicolás Cabrera 1, 28049 Madrid, Spain
| | - Patricia Boya
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biologicas, CIB-CSIC, C/Ramiro de Maeztu 9, 28040 Madrid, Spain.
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32
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Streptococcus pneumoniae disrupts pulmonary immune defence via elastase release following pneumolysin-dependent neutrophil lysis. Sci Rep 2016; 6:38013. [PMID: 27892542 PMCID: PMC5125098 DOI: 10.1038/srep38013] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 11/04/2016] [Indexed: 11/08/2022] Open
Abstract
Streptococcus pneumoniae is a leading cause of bacterial pneumonia and is the principal cause of morbidity and mortality worldwide. Previous studies suggested that excessive activation of neutrophils results in the release of neutrophil elastase, which contributes to lung injury in severe pneumonia. Although both pneumococcal virulence factors and neutrophil elastase contribute to the development and progression of pneumonia, there are no studies analysing relationships between these factors. Here, we showed that pneumolysin, a pneumococcal pore-forming toxin, induced cell lysis in primary isolated human neutrophils, leading to the release of neutrophil elastase. Pneumolysin exerted minimal cytotoxicity against alveolar epithelial cells and macrophages, whereas neutrophil elastase induced detachment of alveolar epithelial cells and impaired phagocytic activity in macrophages. Additionally, activation of neutrophil elastase did not exert bactericidal activity against S. pneumoniae in vitro. P2X7 receptor, which belongs to a family of purinergic receptors, was involved in pneumolysin-induced cell lysis. These findings suggested that infiltrated neutrophils are the primary target cells of pneumolysin, and that S. pneumoniae exploits neutrophil-elastase leakage to induce the disruption of pulmonary immune defences, thereby causing lung injury.
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33
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Malet JK, Cossart P, Ribet D. Alteration of epithelial cell lysosomal integrity induced by bacterial cholesterol-dependent cytolysins. Cell Microbiol 2016; 19. [PMID: 27739224 PMCID: PMC5347955 DOI: 10.1111/cmi.12682] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 10/07/2016] [Accepted: 10/07/2016] [Indexed: 12/14/2022]
Abstract
Bacterial pathogens can interfere during infection with host cell organelles, such as mitochondria, the endoplasmic reticulum‐Golgi system or nuclei. As important cellular functions are often compartmentalized in these organelles, their targeting allows pathogens to manipulate key host functions during infection. Here, we identify lysosomes as a new class of organelles targeted by the pathogenic bacterium Listeria monocytogenes. We demonstrate that extracellular Listeria, via secretion of the pore‐forming toxin listeriolysin O, alters lysosomal integrity in epithelial cells but not in macrophages. Listeriolysin O induces lysosomal membrane permeabilization and release of lysosomal content, such as cathepsins proteases, which remain transiently active in the host cytosol. We furthermore show that other bacterial pore‐forming toxins, such as perfringolysin O and pneumolysin, also induce lysosomes alteration. Together, our data unveil a novel activity of bacterial cholesterol‐dependent cytolysins.
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Affiliation(s)
- Julien Karim Malet
- Unité des Interactions Bactéries-Cellules, Institut Pasteur, F-75015, Paris, France.,Inserm, U604, F-75015, Paris, France.,INRA, USC2020, F-75015, Paris, France.,Univ. Paris Diderot, Sorbonne Paris Cité, F-75015, Paris, France
| | - Pascale Cossart
- Unité des Interactions Bactéries-Cellules, Institut Pasteur, F-75015, Paris, France.,Inserm, U604, F-75015, Paris, France.,INRA, USC2020, F-75015, Paris, France
| | - David Ribet
- Unité des Interactions Bactéries-Cellules, Institut Pasteur, F-75015, Paris, France.,Inserm, U604, F-75015, Paris, France.,INRA, USC2020, F-75015, Paris, France
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34
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Jim KK, Engelen-Lee J, van der Sar AM, Bitter W, Brouwer MC, van der Ende A, Veening JW, van de Beek D, Vandenbroucke-Grauls CMJE. Infection of zebrafish embryos with live fluorescent Streptococcus pneumoniae as a real-time pneumococcal meningitis model. J Neuroinflammation 2016; 13:188. [PMID: 27542968 PMCID: PMC4992281 DOI: 10.1186/s12974-016-0655-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 07/08/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Streptococcus pneumoniae is one of the most important causes of bacterial meningitis, an infection where unfavourable outcome is driven by bacterial and host-derived toxins. In this study, we developed and characterized a pneumococcal meningitis model in zebrafish embryos that allows for real-time investigation of early host-microbe interaction. METHODS Zebrafish embryos were infected in the caudal vein or hindbrain ventricle with green fluorescent wild-type S. pneumoniae D39 or a pneumolysin-deficient mutant. The kdrl:mCherry transgenic zebrafish line was used to visualize the blood vessels, whereas phagocytic cells were visualized by staining with far red anti-L-plastin or in mpx:GFP/mpeg1:mCherry zebrafish, that have green fluorescent neutrophils and red fluorescent macrophages. Imaging was performed by fluorescence confocal and time-lapse microscopy. RESULTS After infection by caudal vein, we saw focal clogging of the pneumococci in the blood vessels and migration of bacteria through the blood-brain barrier into the subarachnoid space and brain tissue. Infection with pneumolysin-deficient S. pneumoniae in the hindbrain ventricle showed attenuated growth and migration through the brain as compared to the wild-type strain. Time-lapse and confocal imaging revealed that the initial innate immune response to S. pneumoniae in the subarachnoid space mainly consisted of neutrophils and that pneumolysin-mediated cytolytic activity caused a marked reduction of phagocytes. CONCLUSIONS This new meningitis model permits detailed analysis and visualization of host-microbe interaction in pneumococcal meningitis in real time and is a very promising tool to further our insights in the pathogenesis of pneumococcal meningitis.
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Affiliation(s)
- Kin Ki Jim
- Department of Medical Microbiology and Infection Control, VU University Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
- Department of Neurology, Center of Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - JooYeon Engelen-Lee
- Department of Neurology, Center of Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Astrid M van der Sar
- Department of Medical Microbiology and Infection Control, VU University Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Wilbert Bitter
- Department of Medical Microbiology and Infection Control, VU University Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Matthijs C Brouwer
- Department of Neurology, Center of Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Arie van der Ende
- Department of Medical Microbiology, Center of Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
- The Netherlands Reference Laboratory for Bacterial Meningitis, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Jan-Willem Veening
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Diederik van de Beek
- Department of Neurology, Center of Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Christina M J E Vandenbroucke-Grauls
- Department of Medical Microbiology and Infection Control, VU University Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands.
- Department of Medical Microbiology and Infection Control, VU University Medical Center, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands.
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35
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Abstract
Streptococcus pneumoniae is an opportunistic pathogen globally associated with significant morbidity and mortality. It is capable of causing a wide range of diseases including sinusitis, conjunctivitis, otitis media, pneumonia, bacteraemia, sepsis, and meningitis. While its capsular polysaccharide is indispensible for invasive disease, and opsonising antibodies against the capsule are the basis for the current vaccines, a long history of biomedical research indicates that other components of this Gram-positive bacterium are also critical for virulence. Herein we review the contribution of pneumococcal virulence determinants to survival and persistence in the context of distinct anatomical sites. We discuss how these determinants allow the pneumococcus to evade mucociliary clearance during colonisation, establish lower respiratory tract infection, resist complement deposition and opsonophagocytosis in the bloodstream, and invade secondary tissues such as the central nervous system leading to meningitis. We do so in a manner that highlights both the critical role of the capsular polysaccharide and the accompanying and necessary protein determinants. Understanding the complex interplay between host and pathogen is necessary to find new ways to prevent pneumococcal infection. This review is an attempt to do so with consideration for the latest research findings.
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36
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Zhang H, Kang L, Yao H, He Y, Wang X, Xu W, Song Z, Yin Y, Zhang X. Streptococcus pneumoniae Endopeptidase O (PepO) Elicits a Strong Innate Immune Response in Mice via TLR2 and TLR4 Signaling Pathways. Front Cell Infect Microbiol 2016; 6:23. [PMID: 26973817 PMCID: PMC4770053 DOI: 10.3389/fcimb.2016.00023] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 02/12/2016] [Indexed: 11/13/2022] Open
Abstract
Interaction between virulence factors of Streptococcus pneumoniae and innate immune receptors elicits host responses through specific signaling pathways during infection. Insights into the signaling events may provide a better knowledge of the starting events for host-pathogen interaction. Here we demonstrated a significant induction of innate immune response elicited by recombinant S. pneumoniae endopeptidase O (rPepO), a newer pneumococcal virulence protein, both in vivo and in vitro. Intratracheal instillation of rPepO protein resulted in significant increase of cytokines production and neutrophils infiltration in mouse lungs. TLR2 or TLR4 deficient mice subjected to rPepO treatment showed decreased cytokines production, reduced neutrophils infiltration and intensified tissue injury as compared with WT mice. Upon stimulation, cytokines TNF-α, IL-6, CXCL1, and CXCL10 were produced by peritoneal exudate macrophages (PEMs) in a TLR2 and TLR4 dependent manner. rPepO-induced cytokines production was markedly decreased in TLR2 or TLR4 deficient PEMs. Further study revealed that cytokines induction relied on the rapid phosphorylation of p38, Akt and p65, not the activation of ERK or JNK. While in TLR2 or TLR4 deficient PEMs the activation of p65 was undetectable. Taken together, these results indicate for the first time that the newer pneumococcal virulence protein PepO activates host innate immune response partially through TLR2 and TLR4 signaling pathways.
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Affiliation(s)
- Hong Zhang
- Department of Laboratory Medicine, Key Laboratory of Diagnostic Medicine (Ministry of Education), Chongqing Medical University Chongqing, China
| | - Lihua Kang
- Department of Laboratory Medicine, Key Laboratory of Diagnostic Medicine (Ministry of Education), Chongqing Medical University Chongqing, China
| | - Hua Yao
- Department of Laboratory Medicine, Key Laboratory of Diagnostic Medicine (Ministry of Education), Chongqing Medical University Chongqing, China
| | - Yujuan He
- Department of Laboratory Medicine, Key Laboratory of Diagnostic Medicine (Ministry of Education), Chongqing Medical University Chongqing, China
| | - Xiaofang Wang
- Department of Laboratory Medicine, Key Laboratory of Diagnostic Medicine (Ministry of Education), Chongqing Medical University Chongqing, China
| | - Wenchun Xu
- Department of Laboratory Medicine, Key Laboratory of Diagnostic Medicine (Ministry of Education), Chongqing Medical University Chongqing, China
| | - Zhixin Song
- Department of Laboratory Medicine, Key Laboratory of Diagnostic Medicine (Ministry of Education), Chongqing Medical University Chongqing, China
| | - Yibing Yin
- Department of Laboratory Medicine, Key Laboratory of Diagnostic Medicine (Ministry of Education), Chongqing Medical University Chongqing, China
| | - Xuemei Zhang
- Department of Laboratory Medicine, Key Laboratory of Diagnostic Medicine (Ministry of Education), Chongqing Medical University Chongqing, China
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37
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Chen M, Xing Y, Lu A, Fang W, Sun B, Chen C, Liao W, Meng G. Internalized Cryptococcus neoformans Activates the Canonical Caspase-1 and the Noncanonical Caspase-8 Inflammasomes. THE JOURNAL OF IMMUNOLOGY 2015; 195:4962-72. [PMID: 26466953 DOI: 10.4049/jimmunol.1500865] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 09/18/2015] [Indexed: 12/15/2022]
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen that causes cryptococcosis in immunocompromised patients as well as immunocompetent individuals. Host cell surface receptors that recognize C. neoformans have been widely studied. However, intracellular sensing of this pathogen is still poorly understood. Our previous studies have demonstrated that both biofilm and acapsular mutant of C. neoformans are able to activate the NOD-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome. In the current study, it was found that opsonization-mediated internalization of encapsulated C. neoformans also activated the canonical NLRP3-apoptosis-associated speck-like protein containing a CARD (ASC)-caspase-1 inflammasome. In addition, the internalized C. neoformans activated the noncanonical NLRP3-ASC-caspase-8 inflammasome as well, which resulted in robust IL-1β secretion and cell death from caspase-1-deficient primary dendritic cells. Interestingly, we found that caspase-1 was inhibitory for the activation of caspase-8 in dendritic cells upon C. neorformans challenge. Further mechanistic studies showed that both phagolysosome membrane permeabilization and potassium efflux were responsible for C. neoformans-induced activation of either the canonical NLRP3-ASC-caspase-1 inflammasome or the noncanonical NLRP3-ASC-caspase-8 inflammasome. Moreover, challenge with zymosan also led to the activation of the noncanonical NLRP3-ASC-caspase-8 inflammasome in cells absent for caspase-1. Collectively, these findings uncover a number of novel signaling pathways for the innate immune response of host cells to C. neoformans infection and suggest that manipulating NLRP3 signaling may help to control fungal challenge.
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Affiliation(s)
- Mingkuan Chen
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; and
| | - Yue Xing
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; and
| | - Ailing Lu
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; and
| | - Wei Fang
- Shanghai Key Laboratory of Molecular Medical Mycology, Changzheng Hospital, Shanghai 200003, China
| | - Bing Sun
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; and
| | - Changbin Chen
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; and
| | - Wanqing Liao
- Shanghai Key Laboratory of Molecular Medical Mycology, Changzheng Hospital, Shanghai 200003, China
| | - Guangxun Meng
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; and
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38
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Jubrail J, Morris P, Bewley MA, Stoneham S, Johnston SA, Foster SJ, Peden AA, Read RC, Marriott HM, Dockrell DH. Inability to sustain intraphagolysosomal killing of Staphylococcus aureus predisposes to bacterial persistence in macrophages. Cell Microbiol 2015; 18:80-96. [PMID: 26248337 PMCID: PMC4778410 DOI: 10.1111/cmi.12485] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 07/07/2015] [Indexed: 12/25/2022]
Abstract
Macrophages are critical effectors of the early innate response to bacteria in tissues. Phagocytosis and killing of bacteria are interrelated functions essential for bacterial clearance but the rate-limiting step when macrophages are challenged with large numbers of the major medical pathogen Staphylococcus aureus is unknown. We show that macrophages have a finite capacity for intracellular killing and fail to match sustained phagocytosis with sustained microbial killing when exposed to large inocula of S. aureus (Newman, SH1000 and USA300 strains). S. aureus ingestion by macrophages is associated with a rapid decline in bacterial viability immediately after phagocytosis. However, not all bacteria are killed in the phagolysosome, and we demonstrate reduced acidification of the phagolysosome, associated with failure of phagolysosomal maturation and reduced activation of cathepsin D. This results in accumulation of viable intracellular bacteria in macrophages. We show macrophages fail to engage apoptosis-associated bacterial killing. Ultittop mately macrophages with viable bacteria undergo cell lysis, and viable bacteria are released and can be internalized by other macrophages. We show that cycles of lysis and reuptake maintain a pool of viable intracellular bacteria over time when killing is overwhelmed and demonstrate intracellular persistence in alveolar macrophages in the lungs in a murine model.
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Affiliation(s)
- Jamil Jubrail
- Department of Infection and Immunity, University of Sheffield, Sheffield, UK.,The Florey Institute, University of Sheffield, Sheffield, UK
| | - Paul Morris
- Department of Infection and Immunity, University of Sheffield, Sheffield, UK.,The Florey Institute, University of Sheffield, Sheffield, UK
| | - Martin A Bewley
- Department of Infection and Immunity, University of Sheffield, Sheffield, UK.,The Florey Institute, University of Sheffield, Sheffield, UK
| | - Simon Stoneham
- Department of Infection and Immunity, University of Sheffield, Sheffield, UK.,The Florey Institute, University of Sheffield, Sheffield, UK
| | - Simon A Johnston
- Department of Infection and Immunity, University of Sheffield, Sheffield, UK.,The Florey Institute, University of Sheffield, Sheffield, UK.,Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | - Simon J Foster
- The Florey Institute, University of Sheffield, Sheffield, UK.,Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | - Andrew A Peden
- Department of Biomedical Sciences, University of Sheffield, Sheffield, UK
| | - Robert C Read
- Academic Unit of Clinical and Experimental Sciences, University of Southampton Medical School, Southampton, UK
| | - Helen M Marriott
- Department of Infection and Immunity, University of Sheffield, Sheffield, UK.,The Florey Institute, University of Sheffield, Sheffield, UK
| | - David H Dockrell
- Department of Infection and Immunity, University of Sheffield, Sheffield, UK.,The Florey Institute, University of Sheffield, Sheffield, UK.,Academic Directorate of Communicable Diseases, Sheffield Teaching Hospitals, Sheffield, UK
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39
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Serotype 1 and 8 Pneumococci Evade Sensing by Inflammasomes in Human Lung Tissue. PLoS One 2015; 10:e0137108. [PMID: 26317436 PMCID: PMC4552725 DOI: 10.1371/journal.pone.0137108] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Accepted: 08/12/2015] [Indexed: 01/08/2023] Open
Abstract
Streptococcus pneumoniae is a major cause of pneumonia, sepsis and meningitis. The pore-forming toxin pneumolysin is a key virulence factor of S. pneumoniae, which can be sensed by the NLRP3 inflammasome. Among the over 90 serotypes, serotype 1 pneumococci (particularly MLST306) have emerged across the globe as a major cause of invasive disease. The cause for its particularity is, however, incompletely understood. We therefore examined pneumococcal infection in human cells and a human lung organ culture system mimicking infection of the lower respiratory tract. We demonstrate that different pneumococcal serotypes differentially activate inflammasome-dependent IL-1β production in human lung tissue and cells. Whereas serotype 2, 3, 6B, 9N pneumococci expressing fully haemolytic pneumolysins activate NLRP3 inflammasome-dependent responses, serotype 1 and 8 strains expressing non-haemolytic toxins are poor activators of IL-1β production. Accordingly, purified haemolytic pneumolysin but not serotype 1-associated non-haemolytic toxin activates strong IL-1β production in human lungs. Our data suggest that the evasion of inflammasome-dependent innate immune responses by serotype 1 pneumococci might contribute to their ability to cause invasive diseases in humans.
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40
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Hu DK, Liu Y, Li XY, Qu Y. In vitro expression of Streptococcus pneumoniae ply gene in human monocytes and pneumocytes. Eur J Med Res 2015; 20:52. [PMID: 25943628 PMCID: PMC4426643 DOI: 10.1186/s40001-015-0142-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 04/27/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Streptococcus pneumoniae is one major cause of pneumonia in human and contains various virulence factors that contribute to pathogenesis of pneumococcal disease. This study investigated the role of pneumolysin, Ply, in facilitating S. pneumoniae invasion into the host blood stream. METHODS S. pneumoniae strains were isolated from clinical blood and sputum samples and confirmed by PCR. Expression of ply gene was assessed by infecting human monocytes and pneumocytes. RESULTS A total of 23 strains of S. pneumoniae isolated from blood (n = 11) and sputum (n = 12) along with S. pneumoniae ATCC49619 were used to infect human monocyte (THP-1) and Type II pneumocyte (A549) cell lines. All clinical strains of S. pneumoniae showed higher expression of ply mRNA than the American Type Culture Collection (ATCC) strain. Among the clinical strains, blood isolates showed higher expression of ply genes than sputum isolates, i.e., 2(1.5)- to 2(1.6)-folds in THP-1 and 2(0.4)- to 2(4.9)-folds in A549 cell lines. CONCLUSIONS The data from the current study demonstrated that ply gene of blood- and sputum-derived S. pneumoniae is differentially expressed in two different cell lines. Under survival pressure, ply is highly expressed in these two cell lines for blood-derived S. pneumoniae, indicating that ply gene may facilitate S. pneumoniae invasion into the host blood system.
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Affiliation(s)
- Da-Kang Hu
- Department of Laboratory Medicine, Taizhou Municipal Hospital, 381# Zhongshan East Road, Taizhou, 318000, China.
| | - Yang Liu
- Department of Laboratory Medicine, The First Affiliated Hospital of Nanchang University, 17# Yong Wai Zheng Street, Nanchang, 330006, China.
| | - Xiang-Yang Li
- Department of Laboratory Medicine, The Second Affiliated Hospital of Wenzhou Medical University, 109# College West Road, Wenzhou, 325027, China.
| | - Ying Qu
- Department of Laboratory Medicine, Taizhou Municipal Hospital, 381# Zhongshan East Road, Taizhou, 318000, China.
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41
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Degradation products of the extracellular pathogen Streptococcus pneumoniae access the cytosol via its pore-forming toxin. mBio 2015; 6:mBio.02110-14. [PMID: 25604786 PMCID: PMC4313911 DOI: 10.1128/mbio.02110-14] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Streptococcus pneumoniae is a leading pathogen with an extracellular lifestyle; however, it is detected by cytosolic surveillance systems of macrophages. The innate immune response that follows cytosolic sensing of cell wall components results in recruitment of additional macrophages, which subsequently clear colonizing organisms from host airways. In this study, we monitored cytosolic access by following the transit of the abundant bacterial surface component capsular polysaccharide, which is linked to the cell wall. Confocal and electron microscopy visually characterized the location of cell wall components in murine macrophages outside membrane-bound organelles. Quantification of capsular polysaccharide through cellular fractionation demonstrated that cytosolic access of bacterial cell wall components is dependent on phagocytosis, bacterial sensitivity to the host’s degradative enzyme lysozyme, and release of the pore-forming toxin pneumolysin. Activation of p38 mitogen-activated protein kinase (MAPK) signaling is important for limiting access to the cytosol; however, ultimately, these are catastrophic events for both the bacteria and the macrophage, which undergoes cell death. Our results show how expression of a pore-forming toxin ensures the death of phagocytes that take up the organism, although cytosolic sensing results in innate immune detection that eventually allows for successful host defense. These findings provide an example of how cytosolic access applies to an extracellular microbe and contributes to its pathogenesis. Importance Streptococcus pneumoniae (the pneumococcus) is a bacterial pathogen that is a leading cause of pneumonia. Pneumococcal disease is preceded by colonization of the nasopharynx, which lasts several weeks before being cleared by the host’s immune system. Although S. pneumoniae is an extracellular microbe, intracellular detection of pneumococcal components is critical for bacterial clearance. In this study, we show that following bacterial uptake and degradation by phagocytes, pneumococcal products access the host cell cytosol via its pore-forming toxin. This phenomenon of cytosolic access results in phagocyte death and may serve to combat the host cells responsible for clearing the organism. Our results provide an example of how intracellular access and subsequent immune detection occurs during infection with an extracellular pathogen. Streptococcus pneumoniae (the pneumococcus) is a bacterial pathogen that is a leading cause of pneumonia. Pneumococcal disease is preceded by colonization of the nasopharynx, which lasts several weeks before being cleared by the host’s immune system. Although S. pneumoniae is an extracellular microbe, intracellular detection of pneumococcal components is critical for bacterial clearance. In this study, we show that following bacterial uptake and degradation by phagocytes, pneumococcal products access the host cell cytosol via its pore-forming toxin. This phenomenon of cytosolic access results in phagocyte death and may serve to combat the host cells responsible for clearing the organism. Our results provide an example of how intracellular access and subsequent immune detection occurs during infection with an extracellular pathogen.
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42
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Bong Y, Shin SG, Koh SH, Lim JH. Interleukin-1β Participates in the Development of Pneumococcal Acute Lung Injury and Death by Promoting Alveolar Microvascular Leakage. ACTA ACUST UNITED AC 2015. [DOI: 10.4167/jbv.2015.45.2.93] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Younghoon Bong
- College of Veterinary Medicine, Chonnam National University, Gwangju, Korea
| | - Seul Gi Shin
- Department of Microbiology, Ewha Womans University School of Medicine, Seoul, Korea
| | - Seo Hyun Koh
- Department of Microbiology, Ewha Womans University School of Medicine, Seoul, Korea
| | - Jae Hyang Lim
- Department of Microbiology, Ewha Womans University School of Medicine, Seoul, Korea
- Gonda Department of Cell and Molecular Biology, House Ear Institute, University of Southern California, Los Angeles, CA, USA
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43
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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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