1
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Jagau H, Packirisamy S, Brandon K, Herwald H. Plasma Protein Layer Concealment Protects Streptococcus pyogenes From Innate Immune Attack. Front Cell Infect Microbiol 2021; 11:633394. [PMID: 34094995 PMCID: PMC8173628 DOI: 10.3389/fcimb.2021.633394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 05/04/2021] [Indexed: 11/13/2022] Open
Abstract
Early recognition and elimination of invading pathogens by the innate immune system, is one of the most efficient host defense mechanisms preventing the induction of systemic complications from infection. To this end the host can mobilize endogenous antimicrobials capable of killing the intruder by perforating the microbial cell wall. Here, we show that Streptococcus pyogenes can shield its outer surface with a layer of plasma proteins. This mechanism protects the bacteria from an otherwise lytic attack by LL-37 and extracellular histones, allowing the bacteria to adjust their gene regulation to an otherwise hostile environment.
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Affiliation(s)
- Hilger Jagau
- Division of Infection Medicine, Department of Clinical Sciences, Lund, Lund University, Lund, Sweden
| | - Swathi Packirisamy
- Division of Infection Medicine, Department of Clinical Sciences, Lund, Lund University, Lund, Sweden
| | - Kyle Brandon
- Division of Infection Medicine, Department of Clinical Sciences, Lund, Lund University, Lund, Sweden.,UCD School of Medicine, University College Dublin, Dublin, Ireland
| | - Heiko Herwald
- Division of Infection Medicine, Department of Clinical Sciences, Lund, Lund University, Lund, Sweden
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2
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Neumann A, Happonen L, Karlsson C, Bahnan W, Frick IM, Björck L. Streptococcal protein SIC activates monocytes and induces inflammation. iScience 2021; 24:102339. [PMID: 33855284 PMCID: PMC8027542 DOI: 10.1016/j.isci.2021.102339] [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: 12/07/2020] [Revised: 02/21/2021] [Accepted: 03/16/2021] [Indexed: 02/08/2023] Open
Abstract
Streptococcus pyogenes is a major bacterial pathogen in the human population and isolates of the clinically important M1 serotype secrete protein Streptococcal inhibitor of complement (SIC) known to interfere with human innate immunity. Here we find that SIC from M1 bacteria interacts with TLR2 and CD14 on monocytes leading to the activation of the NF-κB and p38 MAPK pathways and the release of several pro-inflammatory cytokines (e.g. TNFα and INFγ). In human plasma, SIC binds clusterin and histidine-rich glycoprotein, and whole plasma, and these two purified plasma proteins enhanced the activation of monocytes by SIC. Isolates of the M55 serotype secrete an SIC homolog, but this protein did not activate monocytes. M1 isolates are common in cases of invasive S. pyogenes infections characterized by massive inflammation, and the results of this study indicate that the pro-inflammatory property of SIC contributes to the pathology of these severe clinical conditions.
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Affiliation(s)
- Ariane Neumann
- Division of Infection Medicine, Department of Clinical Sciences, BMC, Lund University, 22184, Lund, Sweden
| | - Lotta Happonen
- Division of Infection Medicine, Department of Clinical Sciences, BMC, Lund University, 22184, Lund, Sweden
| | - Christofer Karlsson
- Division of Infection Medicine, Department of Clinical Sciences, BMC, Lund University, 22184, Lund, Sweden
| | - Wael Bahnan
- Division of Infection Medicine, Department of Clinical Sciences, BMC, Lund University, 22184, Lund, Sweden
| | - Inga-Maria Frick
- Division of Infection Medicine, Department of Clinical Sciences, BMC, Lund University, 22184, Lund, Sweden
| | - Lars Björck
- Division of Infection Medicine, Department of Clinical Sciences, BMC, Lund University, 22184, Lund, Sweden
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3
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Tan LKK, Reglinski M, Teo D, Reza N, Lamb LEM, Nageshwaran V, Turner CE, Wikstrom M, Frick IM, Bjorck L, Sriskandan S. Vaccine-induced, but not natural immunity, against the Streptococcal inhibitor of complement protects against invasive disease. NPJ Vaccines 2021; 6:62. [PMID: 33888727 PMCID: PMC8062509 DOI: 10.1038/s41541-021-00326-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Accepted: 03/23/2021] [Indexed: 01/25/2023] Open
Abstract
Highly pathogenic emm1 Streptococcus pyogenes strains secrete the multidomain Streptococcal inhibitor of complement (SIC) that binds and inactivates components of the innate immune response. We aimed to determine if naturally occurring or vaccine-induced antibodies to SIC are protective against invasive S. pyogenes infection. Immunisation with full-length SIC protected mice against systemic bacterial dissemination following intranasal or intramuscular infection with emm1 S. pyogenes. Vaccine-induced rabbit anti-SIC antibodies, but not naturally occurring human anti-SIC antibodies, enhanced bacterial clearance in an ex vivo whole-blood assay. SIC vaccination of both mice and rabbits resulted in antibody recognition of all domains of SIC, whereas naturally occurring human anti-SIC antibodies recognised the proline-rich region of SIC only. We, therefore, propose a model whereby natural infection with S. pyogenes generates non-protective antibodies against the proline-rich region of SIC, while vaccination with full-length SIC permits the development of protective antibodies against all SIC domains.
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Affiliation(s)
- Lionel K K Tan
- Section of Adult Infectious Disease, Department of Infectious Disease, Imperial College London, London, UK
| | - Mark Reglinski
- Section of Adult Infectious Disease, Department of Infectious Disease, Imperial College London, London, UK.,School of Life Sciences, University of Dundee, Dundee, UK
| | - Daryl Teo
- Section of Adult Infectious Disease, Department of Infectious Disease, Imperial College London, London, UK
| | - Nada Reza
- Section of Adult Infectious Disease, Department of Infectious Disease, Imperial College London, London, UK
| | - Lucy E M Lamb
- Section of Adult Infectious Disease, Department of Infectious Disease, Imperial College London, London, UK.,Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK
| | - Vaitehi Nageshwaran
- Section of Adult Infectious Disease, Department of Infectious Disease, Imperial College London, London, UK
| | - Claire E Turner
- Section of Adult Infectious Disease, Department of Infectious Disease, Imperial College London, London, UK.,The Florey Institute, University of Sheffield, Sheffield, UK
| | - Mats Wikstrom
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark.,Amgen Inc, Attribute Sciences, Thousand Oaks, CA, USA
| | - Inga-Maria Frick
- Department of Clinical Sciences, Division of Infection Medicine, Lund University, Lund, Sweden
| | - Lars Bjorck
- Department of Clinical Sciences, Division of Infection Medicine, Lund University, Lund, Sweden
| | - Shiranee Sriskandan
- Section of Adult Infectious Disease, Department of Infectious Disease, Imperial College London, London, UK.
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4
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Siemens N, Snäll J, Svensson M, Norrby-Teglund A. Pathogenic Mechanisms of Streptococcal Necrotizing Soft Tissue Infections. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1294:127-150. [PMID: 33079367 DOI: 10.1007/978-3-030-57616-5_9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Necrotizing skin and soft tissue infections (NSTIs) are severe life-threatening and rapidly progressing infections. Beta-hemolytic streptococci, particularly S. pyogenes (group A streptococci (GAS)) but also S. dysgalactiae subsp. equisimilis (SDSE, most group G and C streptococcus), are the main causative agents of monomicrobial NSTIs and certain types, such as emm1 and emm3, are over-represented in NSTI cases. An arsenal of bacterial virulence factors contribute to disease pathogenesis, which is a complex and multifactorial process. In this chapter, we summarize data that have provided mechanistic and immuno-pathologic insight into host-pathogens interactions that contribute to tissue pathology in streptococcal NSTIs. The role of streptococcal surface associated and secreted factors contributing to the hyper-inflammatory state and immune evasion, bacterial load in the tissue and persistence strategies, including intracellular survival and biofilm formation, as well as strategies to mimic NSTIs in vitro are discussed.
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Affiliation(s)
- Nikolai Siemens
- Department of Molecular Genetics and Infection Biology, University of Greifswald, Greifswald, Germany.
| | - Johanna Snäll
- Department of Medicine, Center for Infectious Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Mattias Svensson
- Department of Medicine, Center for Infectious Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Anna Norrby-Teglund
- Department of Medicine, Center for Infectious Medicine, Karolinska Institutet, Huddinge, Sweden
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5
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Frick IM, Shannon O, Neumann A, Karlsson C, Wikström M, Björck L. Streptococcal inhibitor of complement (SIC) modulates fibrinolysis and enhances bacterial survival within fibrin clots. J Biol Chem 2018; 293:13578-13591. [PMID: 30002122 PMCID: PMC6120194 DOI: 10.1074/jbc.ra118.001988] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 07/11/2018] [Indexed: 11/06/2022] Open
Abstract
Some strains of the bacterial pathogen Streptococcus pyogenes secrete protein SIC (streptococcal inhibitor of complement), including strains of the clinically relevant M1 serotype. SIC neutralizes the effect of a number of antimicrobial proteins/peptides and interferes with the function of the host complement system. Previous studies have shown that some S. pyogenes proteins bind and modulate coagulation and fibrinolysis factors, raising the possibility that SIC also may interfere with the activity of these factors. Here we show that SIC interacts with both human thrombin and plasminogen, key components of coagulation and fibrinolysis. We found that during clot formation, SIC binds fibrin through its central region and that SIC inhibits fibrinolysis by interacting with plasminogen. Flow cytometry results indicated that SIC and plasminogen bind simultaneously to S. pyogenes bacteria, and fluorescence microscopy revealed co-localization of the two proteins at the bacterial surface. As a consequence, SIC-expressing bacteria entrapped in clots inhibit fibrinolysis, leading to delayed bacterial escape from the clots as compared with mutant bacteria lacking SIC. Moreover, within the clots SIC-expressing bacteria were protected against killing. In an animal model of subcutaneous infection, SIC-expressing bacteria exhibited a delayed systemic spread. These results demonstrate that the bacterial protein SIC interferes with coagulation and fibrinolysis and thereby enhances bacterial survival, a finding that has significant implications for S. pyogenes virulence.
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Affiliation(s)
- Inga-Maria Frick
- From the Department of Clinical Sciences, Lund, Division of Infection Medicine, Lund University, SE-22184 Lund, Sweden and
| | - Oonagh Shannon
- From the Department of Clinical Sciences, Lund, Division of Infection Medicine, Lund University, SE-22184 Lund, Sweden and
| | - Ariane Neumann
- From the Department of Clinical Sciences, Lund, Division of Infection Medicine, Lund University, SE-22184 Lund, Sweden and
| | - Christofer Karlsson
- From the Department of Clinical Sciences, Lund, Division of Infection Medicine, Lund University, SE-22184 Lund, Sweden and
| | - Mats Wikström
- the University of Copenhagen, Protein Function and Interactions Group, Novo Nordisk Foundation Center for Protein Research, DK-2200 Copenhagen, Denmark
| | - Lars Björck
- From the Department of Clinical Sciences, Lund, Division of Infection Medicine, Lund University, SE-22184 Lund, Sweden and
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6
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Novel Two-Component System of Streptococcus sanguinis Affecting Functions Associated with Viability in Saliva and Biofilm Formation. Infect Immun 2018; 86:IAI.00942-17. [PMID: 29339459 DOI: 10.1128/iai.00942-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 01/08/2018] [Indexed: 02/07/2023] Open
Abstract
Streptococcus sanguinis is a pioneer species of teeth and a common opportunistic pathogen of infective endocarditis. In this study, we identified a two-component system, S. sanguinis SptRS (SptRS Ss ), affecting S. sanguinis survival in saliva and biofilm formation. Isogenic mutants of sptRSs (SKsptR) and sptSSs (SKsptS) showed reduced cell counts in ex vivo assays of viability in saliva compared to those of parent strain SK36 and complemented mutants. Reduced counts of the mutants in saliva were associated with reduced growth rates in nutrient-poor medium (RPMI) and increased susceptibility to the deposition of C3b and the membrane attach complex (MAC) of the complement system, a defense component of saliva and serum. Conversely, sptRSs and sptSSs mutants showed increased biofilm formation associated with higher levels of production of H2O2 and extracellular DNA. Reverse transcription-quantitative PCR (RT-qPCR) comparisons of strains indicated a global role of SptRS Ss in repressing genes for H2O2 production (2.5- to 15-fold upregulation of spxB, spxR, vicR, tpk, and ackA in sptRSs and sptSSs mutants), biofilm formation, and/or evasion of host immunity (2.1- to 11.4-fold upregulation of srtA, pcsB, cwdP, iga, and nt5e). Compatible with the homology of SptR Ss with AraC-type regulators, duplicate to multiple conserved repeats were identified in 1,000-bp regulatory regions of downstream genes, suggesting that SptR Ss regulates transcription by DNA looping. Significant transcriptional changes in the regulatory genes vicR, spxR, comE, comX, and mecA in the sptRSs and sptSSs mutants further indicated that SptRS Ss is part of a regulatory network that coordinates cell wall homeostasis, H2O2 production, and competence. This study reveals that SptRS Ss is involved in the regulation of crucial functions for S. sanguinis persistence in the oral cavity.
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7
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Westman J, Chakrakodi B, Snäll J, Mörgelin M, Bruun Madsen M, Hyldegaard O, Neumann A, Frick IM, Norrby-Teglund A, Björck L, Herwald H. Protein SIC Secreted from Streptococcus pyogenes Forms Complexes with Extracellular Histones That Boost Cytokine Production. Front Immunol 2018. [PMID: 29520265 PMCID: PMC5827136 DOI: 10.3389/fimmu.2018.00236] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Innate immunity relies on an effective recognition of the pathogenic microorganism as well as on endogenous danger signals. While bacteria in concert with their secreted virulence factors can cause a number of inflammatory reactions, danger signals released at the site of infection may in addition determine the amplitude of such responses and influence the outcome of the disease. Here, we report that protein SIC, Streptococcal Inhibitor of Complement, an abundant secreted protein from Streptococcus pyogenes, binds to extracellular histones, a group of danger signals released during necrotizing tissue damage. This interaction leads to the formation of large aggregates in vitro. Extracellular histones and SIC are abundantly expressed and seen colocalized in biopsies from patients with necrotizing soft-tissue infections caused by S. pyogenes. In addition, binding of SIC to histones neutralized their antimicrobial activity. Likewise, the ability of histones to induce hemolysis was inhibited in the presence of SIC. However, when added to whole blood, SIC was not able to block the pro-inflammatory effect of histones. Instead SIC boosted the histone-triggered release of a broad range of cytokines and chemokines, including IL-6, TNF-α, IL-8, IL-1β, IL-1ra, G-CSF, and IFN-γ. These results demonstrate that the interaction between SIC and histones has multiple effects on the host response to S. pyogenes infection.
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Affiliation(s)
- Johannes Westman
- Program in Cell Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Bhavya Chakrakodi
- Department of Medicine, Karolinska Institutet, Center for Infectious Medicine, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Johanna Snäll
- Department of Medicine, Karolinska Institutet, Center for Infectious Medicine, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Matthias Mörgelin
- Department of Clinical Sciences, Faculty of Medicine, Division of Infection Medicine, Lund University, Lund, Sweden
| | - Martin Bruun Madsen
- Rigshospitalet, Department of Intensive Care, Copenhagen University Hospital, Copenhagen, Denmark
| | - Ole Hyldegaard
- Rigshospitalet, Hyperbaric Unit, Department of Anesthesia, Center of Head and Orthopedics, Copenhagen, Denmark
| | - Ariane Neumann
- Department of Clinical Sciences, Faculty of Medicine, Division of Infection Medicine, Lund University, Lund, Sweden
| | - Inga-Maria Frick
- Department of Clinical Sciences, Faculty of Medicine, Division of Infection Medicine, Lund University, Lund, Sweden
| | - Anna Norrby-Teglund
- Department of Medicine, Karolinska Institutet, Center for Infectious Medicine, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Lars Björck
- Department of Clinical Sciences, Faculty of Medicine, Division of Infection Medicine, Lund University, Lund, Sweden
| | - Heiko Herwald
- Department of Clinical Sciences, Faculty of Medicine, Division of Infection Medicine, Lund University, Lund, Sweden
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8
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Delabranche X, Helms J, Meziani F. Immunohaemostasis: a new view on haemostasis during sepsis. Ann Intensive Care 2017; 7:117. [PMID: 29197958 PMCID: PMC5712298 DOI: 10.1186/s13613-017-0339-5] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 11/20/2017] [Indexed: 12/12/2022] Open
Abstract
Host infection by a micro-organism triggers systemic inflammation, innate immunity and complement pathways, but also haemostasis activation. The role of thrombin and fibrin generation in host defence is now recognised, and thrombin has become a partner for survival, while it was seen only as one of the "principal suspects" of multiple organ failure and death during septic shock. This review is first focused on pathophysiology. The role of contact activation system, polyphosphates and neutrophil extracellular traps has emerged, offering new potential therapeutic targets. Interestingly, newly recognised host defence peptides (HDPs), derived from thrombin and other "coagulation" factors, are potent inhibitors of bacterial growth. Inhibition of thrombin generation could promote bacterial growth, while HDPs could become novel therapeutic agents against pathogens when resistance to conventional therapies grows. In a second part, we focused on sepsis-induced coagulopathy diagnostic challenge and stratification from "adaptive" haemostasis to "noxious" disseminated intravascular coagulation (DIC) either thrombotic or haemorrhagic. Besides usual coagulation tests, we discussed cellular haemostasis assessment including neutrophil, platelet and endothelial cell activation. Then, we examined therapeutic opportunities to prevent or to reduce "excess" thrombin generation, while preserving "adaptive" haemostasis. The fail of international randomised trials involving anticoagulants during septic shock may modify the hypothesis considering the end of haemostasis as a target to improve survival. On the one hand, patients at low risk of mortality may not be treated to preserve "immunothrombosis" as a defence when, on the other hand, patients at high risk with patent excess thrombin and fibrin generation could benefit from available (antithrombin, soluble thrombomodulin) or ongoing (FXI and FXII inhibitors) therapies. We propose to better assess coagulation response during infection by an improved knowledge of pathophysiology and systematic testing including determination of DIC scores. This is one of the clues to allocate the right treatment for the right patient at the right moment.
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Affiliation(s)
- Xavier Delabranche
- Université de Strasbourg, Faculté de Médecine & Hôpitaux Universitaires de Strasbourg, Service de Réanimation, Nouvel Hôpital Civil, Strasbourg, France
- INSERM (French National Institute of Health and Medical Research), UMR 1260, Regenerative Nanomedicine (RNM), FMTS, Université de Strasbourg, Strasbourg, France
| | - Julie Helms
- Université de Strasbourg, Faculté de Médecine & Hôpitaux Universitaires de Strasbourg, Service de Réanimation, Nouvel Hôpital Civil, Strasbourg, France
- INSERM, EFS Grand Est, BPPS UMR-S 949, Université de Strasbourg, Strasbourg, France
| | - Ferhat Meziani
- Université de Strasbourg, Faculté de Médecine & Hôpitaux Universitaires de Strasbourg, Service de Réanimation, Nouvel Hôpital Civil, Strasbourg, France
- INSERM (French National Institute of Health and Medical Research), UMR 1260, Regenerative Nanomedicine (RNM), FMTS, Université de Strasbourg, Strasbourg, France
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9
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Zhong G. Chlamydial Plasmid-Dependent Pathogenicity. Trends Microbiol 2016; 25:141-152. [PMID: 27712952 DOI: 10.1016/j.tim.2016.09.006] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 09/11/2016] [Accepted: 09/19/2016] [Indexed: 10/20/2022]
Abstract
Most Chlamydia species carry a 7.5kb plasmid encoding eight open reading frames conventionally called plasmid glycoproteins 1-8 or pGP1-8. Although the plasmid is not critical for chlamydial growth in vitro, its role in chlamydial pathogenesis is clearly demonstrated in the genital tracts of mice infected with Chlamydia muridarum, a model for investigating the human pathogen Chlamydia trachomatis. Plasmid-free C. trachomatis is also attenuated in both the mouse genital tract and nonhuman primate ocular tissue. Deficiency in pGP3 alone, which is regulated by pGP4, largely reproduced the in vivo but not in vitro phenotypes of the plasmid-free organisms, suggesting that pGP3 is a key in vivo virulence factor. The positive and negative regulations of some chromosomal genes by pGP4 and pGP5, respectively, may allow the plasmid to promote chlamydial adaptation to varied animal tissue environments. The focus of this review is to summarize the progress on the pathogenic functions of the plasmid-encoded open reading frames, which may motivate further investigation of the molecular mechanisms of chlamydial pathogenicity and development of medical utility of the chlamydial plasmid system.
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Affiliation(s)
- Guangming Zhong
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA.
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10
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Yang Z, Tang L, Zhou Z, Zhong G. Neutralizing antichlamydial activity of complement by chlamydia-secreted protease CPAF. Microbes Infect 2016; 18:669-674. [PMID: 27436813 DOI: 10.1016/j.micinf.2016.07.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 06/22/2016] [Accepted: 07/05/2016] [Indexed: 01/19/2023]
Abstract
Ascending infection by sexually transmitted Chlamydia trachomatis is required for chlamydial induction of tubal pathology. To achieve ascension, the C. trachomatis organisms may have to spread from cell to cell, which inevitably exposes the organisms to extracellular mucosal effectors such as complement factors that are known to possess strong antichlamydial activities. Here, we report that the chlamydia-secreted protease CPAF efficiently neutralized complement factor C3-dependent antichlamydial activity. The neutralization was dependent on the proteolytic activity of CPAF and correlated with the CPAF-mediated degradation of complement factor C3 and factor B. As a result, CPAF preferentially inhibited the alternative complement activation pathway. The significance and limitation of these observations were discussed.
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Affiliation(s)
- Zhangsheng Yang
- Department of Microbiology & Immunology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Lingli Tang
- Department of Clinic Diagnosis, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Zhiguang Zhou
- Department of Endocrinology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Guangming Zhong
- Department of Microbiology & Immunology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA.
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11
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Chlamydial plasmid-encoded virulence factor Pgp3 neutralizes the antichlamydial activity of human cathelicidin LL-37. Infect Immun 2015; 83:4701-9. [PMID: 26416907 DOI: 10.1128/iai.00746-15] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 09/16/2015] [Indexed: 11/20/2022] Open
Abstract
Chlamydia trachomatis infection in the lower genital tract can ascend to and cause pathologies in the upper genital tract, potentially leading to severe complications, such as tubal infertility. However, chlamydial organisms depleted of plasmid or deficient in the plasmid-encoded Pgp3 are attenuated in ascending infection and no longer are able to induce the upper genital tract pathologies, indicating a significant role of Pgp3 in chlamydial pathogenesis. We now report that C. trachomatis Pgp3 can neutralize the antichlamydial activity of human cathelicidin LL-37, a host antimicrobial peptide secreted by both genital tract epithelial cells and infiltrating neutrophils. Pgp3 bound to and formed stable complexes with LL-37. We further showed that the middle region of Pgp3 (Pgp3m) was responsible for both the binding to and neutralization of LL-37, suggesting that Pgp3m can be targeted for attenuating chlamydial pathogenicity or developed for blocking LL-37-involved non-genital-tract pathologies, such as rosacea and psoriasis. Thus, the current study has provided significant information for both understanding the mechanisms of chlamydial pathogenesis and developing novel therapeutic agents.
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12
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Streptococcus pyogenes triggers activation of the human contact system by streptokinase. Infect Immun 2015; 83:3035-42. [PMID: 25987706 DOI: 10.1128/iai.00180-15] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Severe invasive infectious diseases remain a major and life-threatening health problem. In serious cases, a systemic activation of the coagulation cascade is a critical complication that is associated with high mortality rates. We report here that streptokinase, a group A streptococcal plasminogen activator, triggers the activation of the human contact system. Activation of contact system factors at the surface of the Streptococcus pyogenes serotype M49 is dependent on streptokinase and plasminogen. Our results also show that secreted streptokinase is an efficient contact system activator, independent from a contact surface. This results in the processing of high-molecular-weight kininogen and the release of bradykinin, a potent vascular mediator. We further investigated whether the ability of 50 different clinical S. pyogenes isolates to activate the contact system is associated with an invasive phenotype. The data reveal that isolates from invasive infections trigger an activation of the contact system more potently than strains isolated from noninvasive infections. The present study gives new insights into the mechanisms by which S. pyogenes triggers the human contact system and stresses the function of soluble and surface located plasmin exploited as a group A streptococcal virulence factor through the action of streptokinase.
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13
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Berends ETM, Kuipers A, Ravesloot MM, Urbanus RT, Rooijakkers SHM. Bacteria under stress by complement and coagulation. FEMS Microbiol Rev 2014; 38:1146-71. [PMID: 25065463 DOI: 10.1111/1574-6976.12080] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 06/23/2014] [Accepted: 07/14/2014] [Indexed: 02/03/2023] Open
Abstract
The complement and coagulation systems are two related protein cascades in plasma that serve important roles in host defense and hemostasis, respectively. Complement activation on bacteria supports cellular immune responses and leads to direct killing of bacteria via assembly of the Membrane Attack Complex (MAC). Recent studies have indicated that the coagulation system also contributes to mammalian innate defense since coagulation factors can entrap bacteria inside clots and generate small antibacterial peptides. In this review, we will provide detailed insights into the molecular interplay between these protein cascades and bacteria. We take a closer look at how these pathways are activated on bacterial surfaces and discuss the mechanisms by which they directly cause stress to bacterial cells. The poorly understood mechanism for bacterial killing by the MAC will be reevaluated in light of recent structural insights. Finally, we highlight the strategies used by pathogenic bacteria to modulate these protein networks. Overall, these insights will contribute to a better understanding of the host defense roles of complement and coagulation against bacteria.
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Affiliation(s)
- Evelien T M Berends
- Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
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14
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Wollein Waldetoft K, Svensson L, Mörgelin M, Olin AI, Nitsche-Schmitz DP, Björck L, Frick IM. Streptococcal surface proteins activate the contact system and control its antibacterial activity. J Biol Chem 2012; 287:25010-8. [PMID: 22648411 PMCID: PMC3408149 DOI: 10.1074/jbc.m112.373217] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Group G streptococci (GGS) are important bacterial pathogens in humans. Here, we investigated the interactions between GGS and the contact system, a procoagulant and proinflammatory proteolytic cascade that, upon activation, also generates antibacterial peptides. Two surface proteins of GGS, protein FOG and protein G (PG), were found to bind contact system proteins. Experiments utilizing contact protein-deficient human plasma and isogenic GGS mutant strains lacking FOG or PG showed that FOG and PG both activate the procoagulant branch of the contact system. In contrast, only FOG induced cleavage of high molecular weight kininogen, generating the proinflammatory bradykinin peptide and additional high molecular weight kininogen fragments containing the antimicrobial peptide NAT-26. On the other hand, PG protected the bacteria against the antibacterial effect of NAT-26. These findings underline the significance of the contact system in innate immunity and demonstrate that GGS have evolved surface proteins to exploit and modulate its effects.
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Frick IM, Nordin SL, Baumgarten M, Mörgelin M, Sørensen OE, Olin AI, Egesten A. Constitutive and inflammation-dependent antimicrobial peptides produced by epithelium are differentially processed and inactivated by the commensal Finegoldia magna and the pathogen Streptococcus pyogenes. THE JOURNAL OF IMMUNOLOGY 2011; 187:4300-9. [PMID: 21918193 DOI: 10.4049/jimmunol.1004179] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Epithelial linings serve as physical barriers and produce antimicrobial peptides (AMPs) to maintain host integrity. Examples are the bactericidal proteins midkine (MK) and BRAK/CXCL14 that are constitutively produced in the skin epidermal layer, where the anaerobic Gram-positive coccoid commensal Finegoldia magna resides. Consequently, this bacterium is likely to encounter both MK and BRAK/CXCL14, making these molecules possible threats to its habitat. In this study, we show that MK expression is upregulated during inflammation, concomitant with a strong downregulation of BRAK/CXCL14, resulting in changed antibacterial conditions. MK, BRAK/CXCL14, and the inflammation-dependent antimicrobial β-defensins human β-defensin (hBD)-2 and hBD-3 all showed bactericidal activity against both F. magna and the virulent pathogen Streptococcus pyogenes at similar concentrations. SufA, a released protease of F. magna, degraded MK and BRAK/CXCL14 but not hBD-2 nor hBD-3. Cleavage was seen at lysine and arginine residues, amino acids characteristic of AMPs. Intermediate SufA-degraded fragments of MK and BRAK/CXCL14 showed stronger bactericidal activity against S. pyogenes than F. magna, thus promoting survival of the latter. In contrast, the cysteine-protease SpeB of S. pyogenes rapidly degraded all AMPs investigated. The proteins FAF and SIC, released by F. magna and S. pyogenes, respectively, neutralized the antibacterial activity of MK and BRAK/CXCL14, protein FAF being the most efficient. Quantitation and colocalization by immunoelectron microscopy demonstrated significant levels and interactions of the molecules in in vivo and ex vivo samples. The findings reflect strategies used by a permanently residing commensal and a virulent pathogen, the latter operating during the limited time course of invasive disease.
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Affiliation(s)
- Inga-Maria Frick
- Section for Infection Medicine, Department of Clinical Sciences, Lund University, Skåne University Hospital, SE-221 85 Lund, Sweden
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Veneskoski M, Turunen SP, Kummu O, Nissinen A, Rannikko S, Levonen AL, Hörkkö S. Specific recognition of malondialdehyde and malondialdehyde acetaldehyde adducts on oxidized LDL and apoptotic cells by complement anaphylatoxin C3a. Free Radic Biol Med 2011; 51:834-43. [PMID: 21683785 DOI: 10.1016/j.freeradbiomed.2011.05.029] [Citation(s) in RCA: 225] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 05/23/2011] [Accepted: 05/24/2011] [Indexed: 10/18/2022]
Abstract
Oxidatively modified low-density lipoproteins (Ox-LDL) and complement anaphylatoxins C3a and C5a are colocalized in atherosclerotic lesions. Anaphylatoxin C3a also binds and breaks bacterial lipid membranes and phosphatidylcholine liposomes. The role of oxidized lipid adducts in C3a binding to Ox-LDL and apoptotic cells was investigated. Recombinant human C3a bound specifically to low-density lipoprotein and bovine serum albumin modified with malondialdehyde (MDA) and malondialdehyde acetaldehyde (MAA) in chemiluminescence immunoassays. No binding was observed to native proteins, LDL oxidized with copper ions (CuOx-LDL), or phosphocholine. C3a binding to MAA-LDL was inhibited by two monoclonal antibodies specific for MAA-LDL. On agarose gel electrophoresis, C3a comigrated with MDA-LDL and MAA-LDL, but not with native LDL or CuOx-LDL. C3a bound to apoptotic cells in flow cytometry. C3a opsonized MAA-LDL and was taken up by J774A.1 macrophages in immunofluorescence analysis. Complement-activated human serum samples (n=30) showed increased C3a binding to MAA-LDL (P<0.001) and MDA-LDL (P<0.001) compared to nonactivated samples. The amount of C3a bound to MAA-LDL was associated with total complement activity, C3a desArg concentration, and IgG antibody levels to MAA-LDL. Proteins containing MDA adducts or MAA adducts may bind C3a in vivo and contribute to inflammatory processes involving activation of the complement system in atherosclerosis.
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Affiliation(s)
- Marja Veneskoski
- Institute of Diagnostics, Department of Medical Microbiology and Immunology, University of Oulu, 90014 Oulu, Finland
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