1
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Joseph D, Theron AJ, Feldman C, Anderson R, Tintinger GR. Pro-inflammatory interactions of streptolysin O toxin with human neutrophils in vitro. J Immunotoxicol 2024; 21:2345152. [PMID: 38659406 DOI: 10.1080/1547691x.2024.2345152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 04/15/2024] [Indexed: 04/26/2024] Open
Abstract
The recent global resurgence of severe infections caused by the Group A streptococcus (GAS) pathogen, Streptococcus pyogenes, has focused attention on this microbial pathogen, which produces an array of virulence factors, such as the pore-forming toxin, streptolysin O (SOT). Importantly, the interactions of SOT with human neutrophils (PMN), are not well understood. The current study was designed to investigate the effects of pretreatment of isolated human PMN with purified SOT on several pro-inflammatory activities, including generation of reactive oxygen species (ROS), degranulation (elastase release), influx of extracellular calcium (Ca2+) and release of extracellular DNA (NETosis), using chemiluminescence, spectrophotometric and fluorimetric procedures, respectively. Exposure of PMN to SOT alone caused modest production of ROS and elastase release, while pretreatment with the toxin caused significant augmentation of chemoattractant (fMLP)-activated ROS generation and release of elastase by activated PMN. These effects of treatment of PMN with SOT were associated with both a marked and sustained elevation of cytosolic Ca2+concentrations and significant increases in the concentrations of extracellular DNA, indicative of NETosis. The current study has identified a potential role for SOT in augmenting the Ca2+-dependent pro-inflammatory interactions of PMN, which, if operative in a clinical setting, may contribute to hyper-activation of PMN and GAS-mediated tissue injury.
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Affiliation(s)
- D Joseph
- Department of Internal Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - A J Theron
- Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - C Feldman
- Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - R Anderson
- Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - G R Tintinger
- Department of Internal Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
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2
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Zhang L, Hu Z, Yang L, Liu T, Xun J, Zhang Q, Wang X, Gao H, Jin Z. Saikosaponin a promotes neutrophil extracellular trap formation and bactericidal activity. Nat Prod Res 2024:1-8. [PMID: 38635418 DOI: 10.1080/14786419.2024.2343918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 02/26/2024] [Indexed: 04/20/2024]
Abstract
This study aimed to investigate the effects of SSa, one of the major triterpenoid saponins extracted from Radix bupleuri, on neutrophil extracellular trap (NET) formation and the mechanism associated with this process. Using Sytox green and immunofluorescence assays, we found SSa rapidly induced NET formation, which depended on NADPH oxidase (NOX)-independent ROS production and autophagy. Pharmacologic inhibitor studies indicated that ERK and PI3K/AKT signalling were also required for SSa-induced NET formation, whereas protein arginine deiminase 4 (PAD4) was not required. Furthermore, we found that SSa promoted neutrophil bactericidal activity mainly through NET formation. Based on flow cytometry and the Cell Counting Kit-8 (CCK-8) assays, the results demonstrated that SSa-induced NET formation occurred without neutrophil death. Taken together, these findings indicated that SSa could be a potential natural product to boost innate immune defense against pathogen attack via NET formation.
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Affiliation(s)
- Lanqiu Zhang
- Tianjin Nankai Hospital, Tianjin Medical University, Tianjin, China
| | - Zhengwei Hu
- Graduate School, Tianjin Medical University, Tianjin, China
| | - Lei Yang
- Tianjin Nankai Hospital, Tianjin Medical University, Tianjin, China
| | - Tianyu Liu
- Graduate School, Tianjin Medical University, Tianjin, China
| | - Jing Xun
- Tianjin Nankai Hospital, Tianjin Medical University, Tianjin, China
| | - Qi Zhang
- Tianjin Nankai Hospital, Tianjin Medical University, Tianjin, China
| | - Ximo Wang
- Tianjin Haihe Hospital, Tianjin University, Tianjin, China
| | - Hejun Gao
- Department of Anesthesiology, Shenzhen Hospital, Southern Medical University, Shenzhen, China
- The Third School of Clinical Medicine, Southern Medical University, Guangzhou, China
| | - Zhongkui Jin
- Tianjin Nankai Hospital, Tianjin Medical University, Tianjin, China
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3
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González-Jiménez P, Méndez R, Latorre A, Mengot N, Piqueras M, Reyes S, Moscardó A, Alonso R, Amara-Elori I, Menéndez R. Endothelial Damage, Neutrophil Extracellular Traps and Platelet Activation in COVID-19 vs. Community-Acquired Pneumonia: A Case-Control Study. Int J Mol Sci 2023; 24:13194. [PMID: 37686001 PMCID: PMC10488034 DOI: 10.3390/ijms241713194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 08/18/2023] [Accepted: 08/22/2023] [Indexed: 09/10/2023] Open
Abstract
COVID-19 has been a diagnostic and therapeutic challenge. It has marked a paradigm shift when considering other types of pneumonia etiology. We analyzed the biomarkers related to endothelial damage and immunothrombosis in COVID-19 in comparison to community-acquired pneumonia (CAP) through a case-control study of 358 patients with pneumonia (179 hospitalized with COVID-19 vs. 179 matched hospitalized with CAP). Endothelial damage markers (endothelin and proadrenomedullin), neutrophil extracellular traps (NETs) (citrullinated-3 histone, cell-free DNA), and platelet activation (soluble P-selectin) were measured. In-hospital and 1-year follow-up outcomes were evaluated. Endothelial damage, platelet activation, and NET biomarkers are significantly higher in CAP compared to COVID-19. In-hospital mortality in COVID-19 was higher compared to CAP whereas 1-year mortality and cardiovascular complications were higher in CAP. In the univariate analysis (OR 95% CIs), proADM and endothelin were associated with in-hospital mortality (proADM: CAP 3.210 [1.698-6.070], COVID-19 8.977 [3.413-23.609]; endothelin: CAP 1.014 [1.006-1.022], COVID-19 1.024 [1.014-1.034]), in-hospital CVE (proADM: CAP 1.623 [1.080-2.439], COVID-19 2.146 [1.186-3.882]; endothelin: CAP 1.005 [1.000-1.010], COVID-19 1.010 [1.003-1.018]), and 1-year mortality (proADM: CAP 2.590 [1.644-4.080], COVID-19 13.562 [4.872-37.751]; endothelin: CAP 1.008 [1.003-1.013], COVID-19 1.026 [1.016-1.037]). In conclusion, COVID-19 and CAP showed different expressions of endothelial damage and NETs. ProADM and endothelin are associated with short- and long-term mortality.
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Affiliation(s)
- Paula González-Jiménez
- Pneumology Department, La Fe University and Polytechnic Hospital, 46026 Valencia, Spain; (P.G.-J.); (N.M.); (S.R.); (I.A.-E.); (R.M.)
- Respiratory Infections, Health Research Institute La Fe (IISLAFE), 46026 Valencia, Spain;
- Medicine Department, University of Valencia, 46010 Valencia, Spain;
| | - Raúl Méndez
- Pneumology Department, La Fe University and Polytechnic Hospital, 46026 Valencia, Spain; (P.G.-J.); (N.M.); (S.R.); (I.A.-E.); (R.M.)
- Respiratory Infections, Health Research Institute La Fe (IISLAFE), 46026 Valencia, Spain;
- Medicine Department, University of Valencia, 46010 Valencia, Spain;
- Center for Biomedical Research Network in Respiratory Diseases (CIBERES), 28029 Madrid, Spain
| | - Ana Latorre
- Respiratory Infections, Health Research Institute La Fe (IISLAFE), 46026 Valencia, Spain;
| | - Noé Mengot
- Pneumology Department, La Fe University and Polytechnic Hospital, 46026 Valencia, Spain; (P.G.-J.); (N.M.); (S.R.); (I.A.-E.); (R.M.)
| | - Mónica Piqueras
- Medicine Department, University of Valencia, 46010 Valencia, Spain;
- Laboratory Department, La Fe University and Polytechnic Hospital, 46026 Valencia, Spain;
| | - Soledad Reyes
- Pneumology Department, La Fe University and Polytechnic Hospital, 46026 Valencia, Spain; (P.G.-J.); (N.M.); (S.R.); (I.A.-E.); (R.M.)
- Respiratory Infections, Health Research Institute La Fe (IISLAFE), 46026 Valencia, Spain;
| | - Antonio Moscardó
- Hemostasis and Thrombosis Unit, La Fe University and Polytechnic Hospital, 46026 Valencia, Spain;
| | - Ricardo Alonso
- Laboratory Department, La Fe University and Polytechnic Hospital, 46026 Valencia, Spain;
| | - Isabel Amara-Elori
- Pneumology Department, La Fe University and Polytechnic Hospital, 46026 Valencia, Spain; (P.G.-J.); (N.M.); (S.R.); (I.A.-E.); (R.M.)
- Respiratory Infections, Health Research Institute La Fe (IISLAFE), 46026 Valencia, Spain;
- Medicine Department, University of Valencia, 46010 Valencia, Spain;
| | - Rosario Menéndez
- Pneumology Department, La Fe University and Polytechnic Hospital, 46026 Valencia, Spain; (P.G.-J.); (N.M.); (S.R.); (I.A.-E.); (R.M.)
- Respiratory Infections, Health Research Institute La Fe (IISLAFE), 46026 Valencia, Spain;
- Medicine Department, University of Valencia, 46010 Valencia, Spain;
- Center for Biomedical Research Network in Respiratory Diseases (CIBERES), 28029 Madrid, Spain
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Pramitasuri TI, Susilawathi NM, Tarini NMA, Sudewi AAR, Evans MC. Cholesterol dependent cytolysins and the brain: Revealing a potential therapeutic avenue for bacterial meningitis. AIMS Microbiol 2023; 9:647-667. [PMID: 38173970 PMCID: PMC10758573 DOI: 10.3934/microbiol.2023033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 07/24/2023] [Accepted: 08/14/2023] [Indexed: 01/05/2024] Open
Abstract
Bacterial meningitis is a catastrophic nervous system disorder with high mortality and wide range of morbidities. Some of the meningitis-causing bacteria occupy cholesterol dependent cytolysins (CDCs) to increase their pathogenicity and arrange immune-evasion strategy. Studies have observed that the relationship between CDCs and pathogenicity in these meningitides is complex and involves interactions between CDC, blood-brain barrier (BBB), glial cells and neurons. In BBB, these CDCs acts on capillary endothelium, tight junction (TJ) proteins and neurovascular unit (NVU). CDCs also observed to elicit intriguing effects on brain inflammation which involves microglia and astrocyte activations, along with neuronal damage as the end-point of pathological pathways in bacterial meningitis. As some studies mentioned potential advantage of CDC-targeted therapeutic mechanisms to combat CNS infections, it might be a fruitful avenue to deepen our understanding of CDC as a candidate for adjuvant therapy to combat bacterial meningitis.
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Affiliation(s)
- Tjokorda Istri Pramitasuri
- Doctoral Program in Medical Science, Faculty of Medicine, Universitas Udayana, Bali, Indonesia
- Postgraduate Research Student, Faculty of Medicine, Imperial College London, United Kingdom
| | - Ni Made Susilawathi
- Department of Neurology, Faculty of Medicine, Universitas Udayana, Bali, Indonesia
| | - Ni Made Adi Tarini
- Department of Microbiology, Faculty of Medicine, Universitas Udayana-Rumah Sakit Umum Pusat Prof Dr dr IGNG Ngoerah, Bali, Indonesia
| | - AA Raka Sudewi
- Department of Neurology, Faculty of Medicine, Universitas Udayana, Bali, Indonesia
| | - Matthew C Evans
- Pain Research, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, United Kingdom
- Department of Brain Sciences, Care Research and Technology Centre, UK Dementia Research Institute, London, United Kingdom
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5
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Anderson R, Feldman C. The Global Burden of Community-Acquired Pneumonia in Adults, Encompassing Invasive Pneumococcal Disease and the Prevalence of Its Associated Cardiovascular Events, with a Focus on Pneumolysin and Macrolide Antibiotics in Pathogenesis and Therapy. Int J Mol Sci 2023; 24:11038. [PMID: 37446214 DOI: 10.3390/ijms241311038] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 06/26/2023] [Accepted: 06/30/2023] [Indexed: 07/15/2023] Open
Abstract
Despite innovative advances in anti-infective therapies and vaccine development technologies, community-acquired pneumonia (CAP) remains the most persistent cause of infection-related mortality globally. Confronting the ongoing threat posed by Streptococcus pneumoniae (the pneumococcus), the most common bacterial cause of CAP, particularly to the non-immune elderly, remains challenging due to the propensity of the elderly to develop invasive pneumococcal disease (IPD), together with the predilection of the pathogen for the heart. The resultant development of often fatal cardiovascular events (CVEs), particularly during the first seven days of acute infection, is now recognized as a relatively common complication of IPD. The current review represents an update on the prevalence and types of CVEs associated with acute bacterial CAP, particularly IPD. In addition, it is focused on recent insights into the involvement of the pneumococcal pore-forming toxin, pneumolysin (Ply), in subverting host immune defenses, particularly the protective functions of the alveolar macrophage during early-stage disease. This, in turn, enables extra-pulmonary dissemination of the pathogen, leading to cardiac invasion, cardiotoxicity and myocardial dysfunction. The review concludes with an overview of the current status of macrolide antibiotics in the treatment of bacterial CAP in general, as well as severe pneumococcal CAP, including a consideration of the mechanisms by which these agents inhibit the production of Ply by macrolide-resistant strains of the pathogen.
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Affiliation(s)
- Ronald Anderson
- Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria 0001, South Africa
| | - Charles Feldman
- Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand Medical School, 7 York Road, Johannesburg 2193, South Africa
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6
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Zuabi T, Scheuerman O, Dizitzer Y, Amarilyo G, Abu M, Goldberg L, Goldberg B, Shirman N, Vardi Y, Levinsky Y. Elevated C-Reactive Protein With Normal Leukocytes Count Among Children With Fever. Pediatrics 2022; 150:190103. [PMID: 36416012 DOI: 10.1542/peds.2022-057843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/29/2022] [Indexed: 11/24/2022] Open
Abstract
Approximately 40% of patients with highly elevated C-reactive protein had a normal white blood cell count. The majority of them had a bacterial infection.
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Affiliation(s)
- Tarek Zuabi
- Department of Pediatrics B.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Oded Scheuerman
- Department of Pediatrics B.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yotam Dizitzer
- Department of Pediatrics C.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Gil Amarilyo
- Pediatric Rheumatology Unit, Schneider Children's Medical Center of Israel, Petach Tikva, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Mor Abu
- Department of Pediatrics B.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Lotem Goldberg
- Department of Pediatrics B.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Bar Goldberg
- Department of Pediatrics B.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Nina Shirman
- Department of Pediatrics B.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yoav Vardi
- Department of Pediatrics B.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yoel Levinsky
- Department of Pediatrics B.,Pediatric Rheumatology Unit, Schneider Children's Medical Center of Israel, Petach Tikva, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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7
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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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8
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Streptococcus pneumoniae exerts oxidative stress, subverts antioxidant signaling and autophagy in human corneal epithelial cells that is alleviated by tert-Butylhydroquinone. Med Microbiol Immunol 2022; 211:119-132. [PMID: 35325292 DOI: 10.1007/s00430-022-00731-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 03/07/2022] [Indexed: 10/18/2022]
Abstract
Streptococcus pneumoniae is one of the leading causes of bacterial keratitis in the developing world and globally. In the current study, we have determined oxidative stress as pathogenesis of S. pneumoniae infection in corneal tissues and human corneal epithelial cells (HCEC) and explored host immune response of HCEC towards S. pneumoniae. We also determined whether treatment with tert-Butylhydroquinone (tBHQ), a Nrf2 inducer, could alleviate oxidative stress and reduce bacterial cytotoxicity in these cells. Oxidative stress was determined in corneal tissues of patients and HCEC by immunohistochemistry and immunofluorescence analysis, respectively. The expression of antioxidant genes, cytokines and antimicrobial peptides was determined by quantitative PCR. Infection of HCEC by S. pneumoniae was determined by colony-forming units. The autophagy and cell death were determined by fluorescence microscopy. The phosphorylation of signaling proteins was evaluated by immunoblot analysis. S. pneumoniae induced oxidative stress during corneal infections and inhibited antioxidant signaling pathways and immune responses like autophagy. tBHQ aided in restoring Nrf2 activation, reduced reactive oxygen species generation and prevented cytotoxicity and cell death in S. pneumoniae-infected HCEC. tBHQ also induced autophagy in a Nrf2-dependent manner and reduced bacterial survival in HCEC. Increased expression of antimicrobial peptides by tBHQ might have contributed to a reduction of bacterial load and cytotoxicity, as exemplified in LL-37 depleted corneal epithelial cells exposed to S. pneumoniae compared to control siRNA-transfected cells. tBHQ mediates alleviation of oxidative stress induced by S. pneumoniae by activating Nrf2-mediated antioxidant signaling in corneal epithelial cells. tBHQ also enhances expression of antimicrobial peptides in corneal cells and aids in inhibition of bacterial survival and cytotoxicity of HCEC.
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9
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Ulhuq FR, Mariano G. Bacterial pore-forming toxins. MICROBIOLOGY (READING, ENGLAND) 2022; 168:001154. [PMID: 35333704 PMCID: PMC9558359 DOI: 10.1099/mic.0.001154] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 02/03/2022] [Indexed: 12/11/2022]
Abstract
Pore-forming toxins (PFTs) are widely distributed in both Gram-negative and Gram-positive bacteria. PFTs can act as virulence factors that bacteria utilise in dissemination and host colonisation or, alternatively, they can be employed to compete with rival microbes in polymicrobial niches. PFTs transition from a soluble form to become membrane-embedded by undergoing large conformational changes. Once inserted, they perforate the membrane, causing uncontrolled efflux of ions and/or nutrients and dissipating the protonmotive force (PMF). In some instances, target cells intoxicated by PFTs display additional effects as part of the cellular response to pore formation. Significant progress has been made in the mechanistic description of pore formation for the different PFTs families, but in several cases a complete understanding of pore structure remains lacking. PFTs have evolved recognition mechanisms to bind specific receptors that define their host tropism, although this can be remarkably diverse even within the same family. Here we summarise the salient features of PFTs and highlight where additional research is necessary to fully understand the mechanism of pore formation by members of this diverse group of protein toxins.
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Affiliation(s)
- Fatima R. Ulhuq
- Microbes in Health and Disease Theme, Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Giuseppina Mariano
- Microbes in Health and Disease Theme, Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
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10
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Neutrophil-Derived Extracellular Vesicles Activate Platelets after Pneumolysin Exposure. Cells 2021; 10:cells10123581. [PMID: 34944089 PMCID: PMC8700313 DOI: 10.3390/cells10123581] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 12/13/2021] [Accepted: 12/14/2021] [Indexed: 12/12/2022] Open
Abstract
Pneumolysin (PLY) is a pore-forming toxin of Streptococcus pneumoniae that contributes substantially to the inflammatory processes underlying pneumococcal pneumonia and lung injury. Host responses against S. pneumoniae are regulated in part by neutrophils and platelets, both individually and in cooperative interaction. Previous studies have shown that PLY can target both neutrophils and platelets, however, the mechanisms by which PLY directly affects these cells and alters their interactions are not completely understood. In this study, we characterize the effects of PLY on neutrophils and platelets and explore the mechanisms by which PLY may induce neutrophil–platelet interactions. In vitro studies demonstrated that PLY causes the formation of neutrophil extracellular traps (NETs) and the release of extracellular vesicles (EVs) from both human and murine neutrophils. In vivo, neutrophil EV (nEV) levels were increased in mice infected with S. pneumoniae. In platelets, treatment with PLY induced the cell surface expression of P-selectin (CD62P) and binding to annexin V and caused a significant release of platelet EVs (pl-EVs). Moreover, PLY-induced nEVs but not NETs promoted platelet activation. The pretreatment of nEVs with proteinase K inhibited platelet activation, indicating that the surface proteins of nEVs play a role in this process. Our findings demonstrate that PLY activates neutrophils and platelets to release EVs and support an important role for neutrophil EVs in modulating platelet functions in pneumococcal infections.
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11
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Clarithromycin Inhibits Pneumolysin Production via Downregulation of ply Gene Transcription despite Autolysis Activation. Microbiol Spectr 2021; 9:e0031821. [PMID: 34468195 PMCID: PMC8557819 DOI: 10.1128/spectrum.00318-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus pneumoniae, the most common cause of community-acquired pneumonia, causes severe invasive infections, including meningitis and bacteremia. The widespread use of macrolides has been reported to increase the prevalence of macrolide-resistant S. pneumoniae (MRSP), thereby leading to treatment failure in patients with pneumococcal pneumonia. However, previous studies have demonstrated that several macrolides and lincosamides have beneficial effects on MRSP infection since they inhibit the production and release of pneumolysin, a pneumococcal pore-forming toxin released during autolysis. In this regard, we previously demonstrated that the mechanisms underlying the inhibition of pneumolysin release by erythromycin involved both the transcriptional downregulation of the gene encoding pneumolysin and the impairment of autolysis in MRSP. Here, using a cell supernatant of the culture, we have shown that clarithromycin inhibits pneumolysin release in MRSP. However, contrary to previous observations in erythromycin-treated MRSP, clarithromycin upregulated the transcription of the pneumococcal autolysis-related lytA gene and enhanced autolysis, leading to the leakage of pneumococcal DNA. On the other hand, compared to erythromycin, clarithromycin significantly downregulated the gene encoding pneumolysin. In a mouse model of MRSP pneumonia, the administration of both clarithromycin and erythromycin significantly decreased the pneumolysin protein level in bronchoalveolar lavage fluid and improved lung injury and arterial oxygen saturation without affecting bacterial load. Collectively, these in vitro and in vivo data reinforce the benefits of macrolides on the clinical outcomes of patients with pneumococcal pneumonia. IMPORTANCE Pneumolysin is a potent intracellular toxin possessing multiple functions that augment pneumococcal virulence. For over 10 years, sub-MICs of macrolides, including clarithromycin, have been recognized to decrease pneumolysin production and release from pneumococcal cells. However, this study indicates that macrolides significantly slowed pneumococcal growth, which may be related to decreased pneumolysin release recorded by previous studies. In this study, we demonstrated that clarithromycin decreases pneumolysin production through downregulation of ply gene transcription, regardless of its inhibitory activity against bacterial growth. Additionally, administration of clarithromycin resulted in the amelioration of lung injury in a mouse model of pneumonia induced by macrolide-resistant pneumococci. Therefore, therapeutic targeting of pneumolysin offers a good strategy to treat pneumococcal pneumonia.
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12
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Domon H, Terao Y. The Role of Neutrophils and Neutrophil Elastase in Pneumococcal Pneumonia. Front Cell Infect Microbiol 2021; 11:615959. [PMID: 33796475 PMCID: PMC8008068 DOI: 10.3389/fcimb.2021.615959] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 03/01/2021] [Indexed: 12/11/2022] Open
Abstract
Streptococcus pneumoniae, also known as pneumococcus, is a Gram-positive diplococcus and a major human pathogen. This bacterium is a leading cause of bacterial pneumonia, otitis media, meningitis, and septicemia, and is a major cause of morbidity and mortality worldwide. To date, studies on S. pneumoniae have mainly focused on the role of its virulence factors including toxins, cell surface proteins, and capsules. However, accumulating evidence indicates that in addition to these studies, knowledge of host factors and host-pathogen interactions is essential for understanding the pathogenesis of pneumococcal diseases. Recent studies have demonstrated that neutrophil accumulation, which is generally considered to play a critical role in host defense during bacterial infections, can significantly contribute to lung injury and immune subversion, leading to pneumococcal invasion of the bloodstream. Here, we review bacterial and host factors, focusing on the role of neutrophils and their elastase, which contribute to the progression of pneumococcal pneumonia.
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Affiliation(s)
- Hisanori Domon
- Division of Microbiology and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.,Research Center for Advanced Oral Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Yutaka Terao
- Division of Microbiology and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.,Research Center for Advanced Oral Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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13
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Algowhary M. Association between age and infection in patients with acute ST-elevation myocardial infarction. Egypt Heart J 2021; 73:12. [PMID: 33515355 PMCID: PMC7847417 DOI: 10.1186/s43044-021-00137-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 01/21/2021] [Indexed: 12/13/2022] Open
Abstract
Background ST-elevation myocardial infarction (STEMI) in young patients has a unique risk profile. We aimed to detect bacteria in aspirate of infarct artery in young versus old patients. Results Aspirates of consecutive 140 patients who underwent a primary coronary intervention were taken for bacteriological, microscopical, and immunohistochemical (for bacterial pneumolysin) examinations. Their results were calculated in young (≤ 50 years) versus old (> 50 years) patients. Median age (interquartile range) was 45 (38–48) years in young (60 patients) and 59 (55–65) years in old (80 patients) patients, p < 0.0001. Both groups had similar baseline data except age, males, diabetes, hyperlipidemia, family history, lesion length, and ectatic vessel. Different bacteria were cultured in 11.3% of all patients involving 22.6% of young and 2.8% of old patients [hazard ratio 8.03 (95% CI 1.83–51.49), p = 0.002]. By multivariate analyses, age groups and leukocytic count were independent predictors of infection (bacteria and pneumolysin), p = 0.027 and p < 0.0001, respectively. Optimal cutoff value of leukocytic count was 12,250 cells/μl [ROC curve sensitivity 85.7%, specificity 86.4%, and AUC 0.97 (95% CI 0.95–1.0), p < 0.001]. Infection was an independent predictor of STEMI in young versus old patients, p < 0.001. Nevertheless, in-hospital events occurred insignificantly different and neither age groups nor infection was predictor of in-hospital events. Conclusions Young patients had significantly higher percentage of bacteria in their infarcted artery than old patients. High leukocytic count in patients below 50 predicts infection that causes acute myocardial infarction. Antibacterial trials directed toward this group are required for secondary prevention.
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Affiliation(s)
- Magdy Algowhary
- Department of Cardiovascular Medicine, Assiut University Heart Hospital, Assiut University, Asyut, 71515, Egypt.
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14
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Feldman C, Anderson R. Platelets and Their Role in the Pathogenesis of Cardiovascular Events in Patients With Community-Acquired Pneumonia. Front Immunol 2020; 11:577303. [PMID: 33042161 PMCID: PMC7527494 DOI: 10.3389/fimmu.2020.577303] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 08/24/2020] [Indexed: 12/21/2022] Open
Abstract
Community-acquired pneumonia (CAP) remains an important cause of morbidity and mortality throughout the world with much recent and ongoing research focused on the occurrence of cardiovascular events (CVEs) during the infection, which are associated with adverse short-term and long-term survival. Much of the research directed at unraveling the pathogenesis of these events has been undertaken in the settings of experimental and clinical CAP caused by the dangerous, bacterial respiratory pathogen, Streptococcus pneumoniae (pneumococcus), which remains the most common bacterial cause of CAP. Studies of this type have revealed that although platelets play an important role in host defense against infection, there is also increasing recognition that hyperactivation of these cells contributes to a pro-inflammatory, prothrombotic systemic milieu that contributes to the etiology of CVEs. In the case of the pneumococcus, platelet-driven myocardial damage and dysfunction is exacerbated by the direct cardiotoxic actions of pneumolysin, a major pore-forming toxin of this pathogen, which also acts as potent activator of platelets. This review is focused on the role of platelets in host defense against infection, including pneumococcal infection in particular, and reviews the current literature describing the potential mechanisms by which platelet activation contributes to cardiovascular complications in CAP. This is preceded by an evaluation of the burden of pneumococcal infection in CAP, the clinical features and putative pathogenic mechanisms of the CVE, and concludes with an evaluation of the potential utility of the anti-platelet activity of macrolides and various adjunctive therapies.
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Affiliation(s)
- Charles Feldman
- Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Ronald Anderson
- Department of Immunology, Faculty of Health Sciences, Institute of Cellular and Molecular Medicine, University of Pretoria, Pretoria, South Africa
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15
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16
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Hennig-Pauka I, Imker R, Mayer L, Brügmann M, Werckenthin C, Weber H, Menrath A, de Buhr N. From Stable to Lab-Investigating Key Factors for Sudden Deaths Caused by Streptococcus suis. Pathogens 2019; 8:pathogens8040249. [PMID: 31756894 PMCID: PMC6963698 DOI: 10.3390/pathogens8040249] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/13/2019] [Accepted: 11/16/2019] [Indexed: 11/16/2022] Open
Abstract
Swine stocks are endemically infected with the major porcine pathogen Streptococcus (S.) suis. The factors governing the transition from colonizing S. suis residing in the tonsils and the exacerbation of disease have not yet been elucidated. We analyzed the sudden death of fattening pigs kept under extensive husbandry conditions in a zoo. The animals died suddenly of septic shock and showed disseminated intravascular coagulopathy. Genotypic and phenotypic characterizations of the isolated S. suis strains, a tonsillar isolate and an invasive cps type 2 strain, were conducted. Isolated S. suis from dead pigs belonged to cps type 2 strain ST28, whereas one tonsillar S. suis isolate harvested from a healthy animal belonged to ST1173. Neither S. suis growth, induction of neutrophil extracellular traps, nor survival in blood could explain the sudden deaths. Reconstituted blood assays with serum samples from pigs of different age groups from the zoo stock suggested varying protection of individuals against pathogenic cps type 2 strains especially in younger pigs. These findings highlight the benefit of further characterization of the causative strains in each case by sequence typing before autologous vaccine candidate selection.
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Affiliation(s)
- Isabel Hennig-Pauka
- Field Station for Epidemiology, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; (I.H.-P.); (A.M.)
| | - Rabea Imker
- Department of Physiological Chemistry, University of Veterinary Medicine Hannover, 30559 Hannover, Germany;
- Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, 30559 Hannover, Germany
| | - Leonie Mayer
- Institute of Bacteriology and Mycology, Centre for Infectious Diseases, Veterinary Faculty, University of Leipzig, 04109 Leipzig, Germany;
| | - Michael Brügmann
- Food and Veterinary Institute Oldenburg, Lower Saxony State Office for Consumer Protection and Food Safety, 26029 Oldenburg, Germany; (M.B.); (C.W.)
| | - Christiane Werckenthin
- Food and Veterinary Institute Oldenburg, Lower Saxony State Office for Consumer Protection and Food Safety, 26029 Oldenburg, Germany; (M.B.); (C.W.)
| | | | - Andrea Menrath
- Field Station for Epidemiology, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; (I.H.-P.); (A.M.)
| | - Nicole de Buhr
- Department of Physiological Chemistry, University of Veterinary Medicine Hannover, 30559 Hannover, Germany;
- Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, 30559 Hannover, Germany
- Correspondence: ; Tel.: +49-511-953-6119
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17
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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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18
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Zharkova O, Tay SH, Lee HY, Shubhita T, Ong WY, Lateef A, MacAry PA, Lim LHK, Connolly JE, Fairhurst AM. A Flow Cytometry-Based Assay for High-Throughput Detection and Quantification of Neutrophil Extracellular Traps in Mixed Cell Populations. Cytometry A 2018; 95:268-278. [PMID: 30549398 PMCID: PMC6590256 DOI: 10.1002/cyto.a.23672] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 09/26/2018] [Accepted: 10/16/2018] [Indexed: 12/16/2022]
Abstract
Neutrophil extracellular traps (NETs) are web‐like structures composed of decondensed chromatin and antimicrobial proteins that are released into the extracellular space during microbial infections. This active cell death program is known as NETosis. To date, florescence microscopy is the widely accepted method for visualization and quantification of NETs. However, this method is subjective, time consuming and yields low numbers of analyzed polymorphonuclear cells (PMNs) per sample. Increasing interest has emerged on the identification of NETs using flow cytometry techniques. However, flow cytometry analysis of NETs requires particular precautions for sample preparation to obtain reproducible data. Herein, we describe a flow cytometry‐based assay for high‐throughput detection and quantification of NETosis in mixed cell populations. We used fluorescent‐labeled antibodies against cell markers on PMNs together with a combination of nucleic acid stains to measure NETosis in whole blood (WB) and purified PMNs. Using plasma membrane‐impermeable DNA‐binding dye, SYTOX Orange (SO), we found that cell‐appendant DNA of NETting PMNs were positive for SO and DAPI. The combination of optimally diluted antibody and nucleic acid dyes required no washing and yielded low background fluorescence. Significant correlations were found for NETosis from WB and purified PMNs. We then validated the assay by comparing with time‐lapse live cell fluorescence microscopy and determined very good intraassay and interassay variances. The assay was then applied to a disease associated with NETosis, systemic lupus erythematosus (SLE). We examined PMA‐induced NETosis in peripheral PMNs from SLE patients and controls and in bone marrow PMNs from multiple murine models. In summary, this assay is observer‐independent and allows for rapid assessment of a large number of PMNs per sample. Use of this assay does not require sophisticated microscopic equipment like imaging flow cytometers and may be a starting point to analyze extracellular trap formation from immune cells other than PMNs. © 2018 The Authors. Cytometry Part A published by Wiley Periodicals, Inc. on behalf of International Society for Advancement of Cytometry.
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Affiliation(s)
- Olga Zharkova
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Sen Hee Tay
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Department of Medicine, National University Health System, Singapore.,Division of Rheumatology, Department of Medicine, National University Hospital, National University Health System, Singapore.,Singapore Immunology Network, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Hui Yin Lee
- Singapore Immunology Network, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Tripathi Shubhita
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Singapore Immunology Network, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Wei Yee Ong
- Institute for Molecular and Cellular Biology, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Aisha Lateef
- Department of Medicine, National University Health System, Singapore.,Division of Rheumatology, Department of Medicine, National University Hospital, National University Health System, Singapore
| | - Paul Anthony MacAry
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Lina Hsiu Kim Lim
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - John Edward Connolly
- Institute for Molecular and Cellular Biology, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Anna-Marie Fairhurst
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Singapore Immunology Network, Agency for Science, Technology and Research (A*STAR), Singapore
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19
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Anderson R, Nel JG, Feldman C. Multifaceted Role of Pneumolysin in the Pathogenesis of Myocardial Injury in Community-Acquired Pneumonia. Int J Mol Sci 2018; 19:E1147. [PMID: 29641429 PMCID: PMC5979279 DOI: 10.3390/ijms19041147] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 03/14/2018] [Accepted: 03/21/2018] [Indexed: 12/14/2022] Open
Abstract
Pneumolysin (PLY), a member of the family of Gram-positive bacterial, cholesterol-dependent, β-barrel pore-forming cytolysins, is the major protein virulence factor of the dangerous respiratory pathogen, Streptococcus pneumoniae (pneumococcus). PLY plays a major role in the pathogenesis of community-acquired pneumonia (CAP), promoting colonization and invasion of the upper and lower respiratory tracts respectively, as well as extra-pulmonary dissemination of the pneumococcus. Notwithstanding its role in causing acute lung injury in severe CAP, PLY has also been implicated in the development of potentially fatal acute and delayed-onset cardiovascular events, which are now recognized as being fairly common complications of this condition. This review is focused firstly on updating mechanisms involved in the immunopathogenesis of PLY-mediated myocardial damage, specifically the direct cardiotoxic and immunosuppressive activities, as well as the indirect pro-inflammatory/pro-thrombotic activities of the toxin. Secondly, on PLY-targeted therapeutic strategies including, among others, macrolide antibiotics, natural product antagonists, cholesterol-containing liposomes, and fully humanized monoclonal antibodies, as well as on vaccine-based preventive strategies. These sections are preceded by overviews of CAP in general, the role of the pneumococcus as the causative pathogen, the occurrence and types of CAP-associated cardiac complication, and the structure and biological activities of PLY.
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Affiliation(s)
- Ronald Anderson
- Department of Immunology and Institute for Cellular and Molecular Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria 0001, South Africa.
| | - Jan G Nel
- Department of Haematology, Faculty of Health Sciences, University of Pretoria and Tshwane Academic Division of the National Health Laboratory Service, Pretoria 0001, 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 0002, South Africa.
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20
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Influence of Different Bacteria Strains Isolated from Septic Children on Release and Degradation of Extracellular Traps by Neutrophils from Healthy Adults. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1108:1-12. [DOI: 10.1007/5584_2018_245] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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21
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Law SM, Gray RD. Neutrophil extracellular traps and the dysfunctional innate immune response of cystic fibrosis lung disease: a review. J Inflamm (Lond) 2017; 14:29. [PMID: 29299029 PMCID: PMC5745605 DOI: 10.1186/s12950-017-0176-1] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 12/14/2017] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Cystic Fibrosis (CF) is a devastating genetic disease characterised primarily by unrelenting lung inflammation and infection resulting in premature death and significant morbidity. Neutrophil Extracellular Traps (NETs) are possibly key to inflammation in the disease. This review aims to draw together existing research investigating NETs in the context of a dysfunctional innate immune system in CF. MAIN BODY NETs have a limited anti-microbial role in CF and studies have shown they are present in higher numbers in CF airways and their protein constituents correlate with lung function decline. Innate immune system cells express CFTR and myeloid-specific CFTR KO mice have greater neutrophil recruitment and higher pro-inflammatory cytokine production to both sterile and bacterial inflammatory challenges. CFTR KO neutrophils have impaired anti-microbial capacity and intrinsic abnormalities in the pH of their cytoplasm, abnormal protein trafficking, increased neutrophil elastase and myeloperoxidase function, and decreased hypochlorite concentrations in their phagolysosomes. Furthermore, neutrophils from CF patients have less intrinsic apoptosis and may be therefore more likely to make NETs. CFTR KO macrophages have high intraphagolysosomal pH and increased toll-like receptor 4 on their cell surface membranes, which inhibit their anti-microbial capacity and render them hyper-responsive to inflammatory stimuli, respectively. Pharmacological treatments for CF target these intrinsic abnormalities of immune dysfunction. Emerging evidence suggests that the absence of CFTR from neutrophils affects NETosis and the interaction of NETs with macrophages. CONCLUSION Current evidence suggests that NETs contribute to inflammation and lung destruction rather than working effectively in their anti-microbial capacity. Further studies focussing on the pro-inflammatory nature of NET constituents are required to identify the exact mechanistic role of NETs in CF and potential therapeutic interventions.
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Affiliation(s)
- Sheonagh M. Law
- MRC Centre for Inflammation Research, The Queen’s Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ UK
| | - Robert D. Gray
- MRC Centre for Inflammation Research, The Queen’s Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ UK
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22
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Ullah I, Ritchie ND, Evans TJ. The interrelationship between phagocytosis, autophagy and formation of neutrophil extracellular traps following infection of human neutrophils by Streptococcus pneumoniae. Innate Immun 2017; 23:413-423. [PMID: 28399692 PMCID: PMC5505230 DOI: 10.1177/1753425917704299] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 02/15/2017] [Accepted: 02/21/2017] [Indexed: 11/24/2022] Open
Abstract
Neutrophils play an important role in the innate immune response to infection with Streptococcus pneumoniae, the pneumococcus. Pneumococci are phagocytosed by neutrophils and undergo killing after ingestion. Other cellular processes may also be induced, including autophagy and the formation of neutrophil extracellular traps (NETs), which may play a role in bacterial eradication. We set out to determine how these different processes interacted following pneumococcal infection of neutrophils, and the role of the major pneumococcal toxin pneumolysin in these various pathways. We found that pneumococci induced autophagy in neutrophils in a type III phosphatidylinositol-3 kinase dependent fashion that also required the autophagy gene Atg5. Pneumolysin did not affect this process. Phagocytosis was inhibited by pneumolysin but enhanced by autophagy, while killing was accelerated by pneumolysin but inhibited by autophagy. Pneumococci induced extensive NET formation in neutrophils that was not influenced by pneumolysin but was critically dependent on autophagy. While pneumolysin did not affect NET formation, it had a potent inhibitory effect on bacterial trapping within NETs. These findings show a complex interaction between phagocytosis, killing, autophagy and NET formation in neutrophils following pneumococcal infection that contribute to host defence against this pathogen.
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Affiliation(s)
| | - Neil D Ritchie
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow Biomedical research Centre, Glasgow, UK
| | - Tom J Evans
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow Biomedical research Centre, Glasgow, UK
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23
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Bandara M, Skehel JM, Kadioglu A, Collinson I, Nobbs AH, Blocker AJ, Jenkinson HF. The accessory Sec system (SecY2A2) in Streptococcus pneumoniae is involved in export of pneumolysin toxin, adhesion and biofilm formation. Microbes Infect 2017; 19:402-412. [PMID: 28456649 PMCID: PMC5526788 DOI: 10.1016/j.micinf.2017.04.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 03/27/2017] [Accepted: 04/17/2017] [Indexed: 01/04/2023]
Abstract
In Streptococcus pneumoniae TIGR4, genes encoding a SecY2A2 accessory Sec system are present within a locus encoding a serine-rich repeat surface protein PsrP. Mutant strains deleted in secA2 or psrP were deficient in biofilm formation, while the ΔsecA2 mutant was reduced in binding to airway epithelial cells. Cell wall protein (CWP) fractions from the ΔsecA2 mutant, but not from the ΔpsrP mutant, were reduced in haemolytic (pneumolysin) activity. Contact-dependent pneumolysin (Ply) activity of wild type TIGR4 cells was ten-fold greater than that of ΔsecA2 mutant cells suggesting that Ply was not active at the ΔsecA2 cell surface. Ply protein was found to be present in the CWP fraction from the ΔsecA2 mutant, but showed aberrant electrophoretic migration indicative of protein modification. Proteomic analyses led to the discovery that the ΔsecA2 mutant CWP fraction was deficient in two glycosidases as well as other enzymes involved in carbohydrate metabolism. Taken collectively the results suggest that positioning of Ply into the cell wall compartment in active form, together with glycosyl hydrolases and adhesins, requires a functional accessory Sec system.
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Affiliation(s)
- Mikaila Bandara
- School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol, BS1 2LY, UK; School of Cellular & Molecular Medicine, University of Bristol, University Walk, Bristol, BS8 1TD, UK; School of Biochemistry, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - J Mark Skehel
- Biological Mass Spectrometry and Proteomics, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Aras Kadioglu
- Department of Clinical Infection, Microbiology & Immunology, Institute of Infection and Global Health, University of Liverpool, 8 West Derby Street, Liverpool L69 7BE, UK
| | - Ian Collinson
- School of Biochemistry, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Angela H Nobbs
- School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol, BS1 2LY, UK
| | - Ariel J Blocker
- School of Cellular & Molecular Medicine, University of Bristol, University Walk, Bristol, BS8 1TD, UK; School of Biochemistry, University of Bristol, University Walk, Bristol, BS8 1TD, UK.
| | - Howard F Jenkinson
- School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol, BS1 2LY, UK.
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24
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Björnsdottir H, Dahlstrand Rudin A, Klose FP, Elmwall J, Welin A, Stylianou M, Christenson K, Urban CF, Forsman H, Dahlgren C, Karlsson A, Bylund J. Phenol-Soluble Modulin α Peptide Toxins from Aggressive Staphylococcus aureus Induce Rapid Formation of Neutrophil Extracellular Traps through a Reactive Oxygen Species-Independent Pathway. Front Immunol 2017; 8:257. [PMID: 28337204 PMCID: PMC5343011 DOI: 10.3389/fimmu.2017.00257] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 02/21/2017] [Indexed: 12/11/2022] Open
Abstract
Neutrophils have the ability to capture and kill microbes extracellularly through the formation of neutrophil extracellular traps (NETs). These are DNA and protein structures that neutrophils release extracellularly and are believed to function as a defense mechanism against microbes. The classic NET formation process, triggered by, e.g., bacteria, fungi, or by direct stimulation of protein kinase C through phorbol myristate acetate, is an active process that takes several hours and relies on the production of reactive oxygen species (ROS) that are further modified by myeloperoxidase (MPO). We show here that NET-like structures can also be formed by neutrophils after interaction with phenol-soluble modulin α (PSMα) that are cytotoxic membrane-disturbing peptides, secreted from community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA). The PSMα-induced NETs contained the typical protein markers and were able to capture microbes. The PSMα-induced NET structures were disintegrated upon prolonged exposure to DNase-positive S. aureus but not on exposure to DNase-negative Candida albicans. Opposed to classic NETosis, PSMα-triggered NET formation occurred very rapidly, independently of ROS or MPO, and was also manifest at 4°C. These data indicate that rapid NETs release may result from cytotoxic membrane disturbance by PSMα peptides, a process that may be of importance for CA-MRSA virulence.
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Affiliation(s)
- Halla Björnsdottir
- Department of Oral Microbiology and Immunology, Institute of Odontology, Sahlgrenska Academy at University of Gothenburg , Gothenburg , Sweden
| | - Agnes Dahlstrand Rudin
- Department of Oral Microbiology and Immunology, Institute of Odontology, Sahlgrenska Academy at University of Gothenburg , Gothenburg , Sweden
| | - Felix P Klose
- Department of Oral Microbiology and Immunology, Institute of Odontology, Sahlgrenska Academy at University of Gothenburg , Gothenburg , Sweden
| | - Jonas Elmwall
- The Phagocyte Research Laboratory, Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy at University of Gothenburg , Gothenburg , Sweden
| | - Amanda Welin
- The Phagocyte Research Laboratory, Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy at University of Gothenburg , Gothenburg , Sweden
| | - Marios Stylianou
- Antifungal Immunity Group, Department of Clinical Microbiology, Umeå University , Umeå , Sweden
| | - Karin Christenson
- Department of Oral Microbiology and Immunology, Institute of Odontology, Sahlgrenska Academy at University of Gothenburg , Gothenburg , Sweden
| | - Constantin F Urban
- Antifungal Immunity Group, Department of Clinical Microbiology, Umeå University , Umeå , Sweden
| | - Huamei Forsman
- The Phagocyte Research Laboratory, Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy at University of Gothenburg , Gothenburg , Sweden
| | - Claes Dahlgren
- The Phagocyte Research Laboratory, Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy at University of Gothenburg , Gothenburg , Sweden
| | - Anna Karlsson
- The Phagocyte Research Laboratory, Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy at University of Gothenburg , Gothenburg , Sweden
| | - Johan Bylund
- Department of Oral Microbiology and Immunology, Institute of Odontology, Sahlgrenska Academy at University of Gothenburg , Gothenburg , Sweden
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25
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Andre GO, Converso TR, Politano WR, Ferraz LFC, Ribeiro ML, Leite LCC, Darrieux M. Role of Streptococcus pneumoniae Proteins in Evasion of Complement-Mediated Immunity. Front Microbiol 2017; 8:224. [PMID: 28265264 PMCID: PMC5316553 DOI: 10.3389/fmicb.2017.00224] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 01/31/2017] [Indexed: 12/14/2022] Open
Abstract
The complement system plays a central role in immune defense against Streptococcus pneumoniae. In order to evade complement attack, pneumococci have evolved a number of mechanisms that limit complement mediated opsonization and subsequent phagocytosis. This review focuses on the strategies employed by pneumococci to circumvent complement mediated immunity, both in vitro and in vivo. At last, since many of the proteins involved in interactions with complement components are vaccine candidates in different stages of validation, we explore the use of these antigens alone or in combination, as potential vaccine approaches that aim at elimination or drastic reduction in the ability of this bacterium to evade complement.
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Affiliation(s)
- Greiciely O Andre
- Laboratório de Biologia Celular e Molecular de Microrganismos, Universidade São Francisco Bragança Paulista, Brazil
| | - Thiago R Converso
- Centro de Biotecnologia, Instituto ButantanSão Paulo, Brazil; Programa de Pós-graduação Interunidades em Biotecnologia, Universidade de São PauloSão Paulo, Brazil
| | - Walter R Politano
- Laboratório de Biologia Celular e Molecular de Microrganismos, Universidade São Francisco Bragança Paulista, Brazil
| | - Lucio F C Ferraz
- Laboratório de Biologia Celular e Molecular de Microrganismos, Universidade São Francisco Bragança Paulista, Brazil
| | - Marcelo L Ribeiro
- Laboratório de Farmacologia, Universidade São Francisco Bragança Paulista, Brazil
| | | | - Michelle Darrieux
- Laboratório de Biologia Celular e Molecular de Microrganismos, Universidade São Francisco Bragança Paulista, Brazil
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