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Garrigues RJ, Thomas S, Leong JM, Garcia BL. Outer surface lipoproteins from the Lyme disease spirochete exploit the molecular switch mechanism of the complement protease C1s. J Biol Chem 2022; 298:102557. [PMID: 36183830 PMCID: PMC9637899 DOI: 10.1016/j.jbc.2022.102557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/23/2022] [Accepted: 09/26/2022] [Indexed: 10/14/2022] Open
Abstract
Proteolytic cascades comprise several important physiological systems, including a primary arm of innate immunity called the complement cascade. To safeguard against complement-mediated attack, the etiologic agent of Lyme disease, Borreliella burgdorferi, produces numerous outer surface-localized lipoproteins that contribute to successful complement evasion. Recently, we discovered a pair of B. burgdorferi surface lipoproteins of the OspEF-related protein family-termed ElpB and ElpQ-that inhibit antibody-mediated complement activation. In this study, we investigate the molecular mechanism of ElpB and ElpQ complement inhibition using an array of biochemical and biophysical approaches. In vitro assays of complement activation show that an independently folded homologous C-terminal domain of each Elp protein maintains full complement inhibitory activity and selectively inhibits the classical pathway. Using binding assays and complement component C1s enzyme assays, we show that binding of Elp proteins to activated C1s blocks complement component C4 cleavage by competing with C1s-C4 binding without occluding the active site. C1s-mediated C4 cleavage is dependent on activation-induced binding sites, termed exosites. To test whether these exosites are involved in Elp-C1s binding, we performed site-directed mutagenesis, which showed that ElpB and ElpQ binding require C1s residues in the anion-binding exosite located on the serine protease domain of C1s. Based on these results, we propose a model whereby ElpB and ElpQ exploit activation-induced conformational changes that are normally important for C1s-mediated C4 cleavage. Our study expands the known complement evasion mechanisms of microbial pathogens and reveals a novel molecular mechanism for selective C1s inhibition by Lyme disease spirochetes.
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2
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Chopra D, Arens RA, Amornpairoj W, Lowes MA, Tomic-Canic M, Strbo N, Lev-Tov H, Pastar I. Innate immunity and microbial dysbiosis in hidradenitis suppurativa – vicious cycle of chronic inflammation. Front Immunol 2022; 13:960488. [PMID: 35967376 PMCID: PMC9368759 DOI: 10.3389/fimmu.2022.960488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 07/01/2022] [Indexed: 11/29/2022] Open
Abstract
Hidradenitis Suppurativa (HS) is a chronic multifactorial inflammatory skin disease with incompletely understood mechanisms of disease pathology. HS is characterized by aberrant activation of the innate immune system, resulting in activation of pathways that aim to protect against pathogenic microorganisms, and also contribute to failure to resolve inflammation. Imbalance in innate immunity is evident in deregulation of host antimicrobial peptides (AMPs) and the complement system associated with the microbiome dysbiosis. The pathology is further complicated by ability of pathogens associated with HS to overcome host immune response. Potential roles of major AMPs, cathelicidin, defensins, dermcidin, S100 proteins, RNAse 7 and complement proteins are discussed. Dysregulated expression pattern of innate immunity components in conjunction with bacterial component of the disease warrants consideration of novel treatment approaches targeting both host immunity and pathogenic microbiome in HS.
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Affiliation(s)
- Divya Chopra
- Wound Healing and Regenerative Medicine Research Program, Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Rachel A. Arens
- College of Medicine, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Watcharee Amornpairoj
- Wound Healing and Regenerative Medicine Research Program, Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Michelle A. Lowes
- Laboratory for Investigative Dermatology, The Rockefeller University, New York, NY, United States
| | - Marjana Tomic-Canic
- Wound Healing and Regenerative Medicine Research Program, Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Natasa Strbo
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Hadar Lev-Tov
- Wound Healing and Regenerative Medicine Research Program, Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, United States
- *Correspondence: Irena Pastar, ; Hadar Lev-Tov,
| | - Irena Pastar
- Wound Healing and Regenerative Medicine Research Program, Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, United States
- *Correspondence: Irena Pastar, ; Hadar Lev-Tov,
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3
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Dunphy RW, Wahid AA, Back CR, Martin RL, Watts AG, Dodson CA, Crennell SJ, van den Elsen JMH. Staphylococcal Complement Evasion Protein Sbi Stabilises C3d Dimers by Inducing an N-Terminal Helix Swap. Front Immunol 2022; 13:892234. [PMID: 35693766 PMCID: PMC9174452 DOI: 10.3389/fimmu.2022.892234] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 04/25/2022] [Indexed: 11/25/2022] Open
Abstract
Staphylococcus aureus is an opportunistic pathogen that is able to thwart an effective host immune response by producing a range of immune evasion molecules, including S. aureus binder of IgG (Sbi) which interacts directly with the central complement component C3, its fragments and associated regulators. Recently we reported the first structure of a disulfide-linked human C3d17C dimer and highlighted its potential role in modulating B-cell activation. Here we present an X-ray crystal structure of a disulfide-linked human C3d17C dimer, which undergoes a structurally stabilising N-terminal 3D domain swap when in complex with Sbi. These structural studies, in combination with circular dichroism and fluorescence spectroscopic analyses, reveal the mechanism underpinning this unique helix swap event and could explain the origins of a previously discovered N-terminally truncated C3dg dimer isolated from rat serum. Overall, our study unveils a novel staphylococcal complement evasion mechanism which enables the pathogen to harness the ability of dimeric C3d to modulate B-cell activation.
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Affiliation(s)
- Rhys W Dunphy
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Ayla A Wahid
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Catherine R Back
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Rebecca L Martin
- Department of Pharmacy and Pharmacology, University of Bath, Bath, United Kingdom
| | - Andrew G Watts
- Department of Pharmacy and Pharmacology, University of Bath, Bath, United Kingdom
| | - Charlotte A Dodson
- Department of Pharmacy and Pharmacology, University of Bath, Bath, United Kingdom
| | - Susan J Crennell
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Jean M H van den Elsen
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom.,Centre for Therapeutic Innovation, University of Bath, Bath, United Kingdom
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4
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Xu X, Marffy ALL, Keightley A, McCarthy AJ, Geisbrecht BV. Group B Streptococcus Surface Protein β: Structural Characterization of a Complement Factor H-Binding Motif and Its Contribution to Immune Evasion. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 208:1232-1247. [PMID: 35110419 PMCID: PMC8881398 DOI: 10.4049/jimmunol.2101078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 12/10/2021] [Indexed: 11/19/2022]
Abstract
The β protein from group B Streptococcus (GBS) is a ∼132-kDa, cell-surface exposed molecule that binds to multiple host-derived ligands, including complement factor H (FH). Many details regarding this interaction and its significance to immune evasion by GBS remain unclear. In this study, we identified a three-helix bundle domain within the C-terminal half of the B75KN region of β as the major FH-binding determinant and determined its crystal structure at 2.5 Å resolution. Analysis of this structure suggested a role in FH binding for a loop region connecting helices α1 and α2, which we confirmed by mutagenesis and direct binding studies. Using a combination of protein cross-linking and mass spectrometry, we observed that B75KN bound to complement control protein (CCP)3 and CCP4 domains of FH. Although this binding site lies within a complement regulatory region of FH, we determined that FH bound by β retained its decay acceleration and cofactor activities. Heterologous expression of β by Lactococcus lactis resulted in recruitment of FH to the bacterial surface and a significant reduction of C3b deposition following exposure to human serum. Surprisingly, we found that FH binding by β was not required for bacterial resistance to phagocytosis by neutrophils or killing of bacteria by whole human blood. However, loss of the B75KN region significantly diminished bacterial survival in both assays. Although our results show that FH recruited to the bacterial surface through a high-affinity interaction maintains key complement-regulatory functions, they raise questions about the importance of FH binding to immune evasion by GBS as a whole.
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Affiliation(s)
- Xin Xu
- Department of Biochemistry & Molecular Biophysics, Kansas State University; Manhattan, KS U.S.A
| | - Alexander L. Lewis Marffy
- Department of Infectious Diseases, Section of Molecular Microbiology, MRC Centre for Molecular Bacteriology & Infection, Imperial College London; London, U.K
| | - Andrew Keightley
- Department of Opthamology, School of Medicine, University of Missouri-Kansas City; Kansas City, MO U.S.A
| | - Alex J. McCarthy
- Department of Infectious Diseases, Section of Molecular Microbiology, MRC Centre for Molecular Bacteriology & Infection, Imperial College London; London, U.K
| | - Brian V. Geisbrecht
- Department of Biochemistry & Molecular Biophysics, Kansas State University; Manhattan, KS U.S.A.,To whom correspondence should be addressed: Brian V. Geisbrecht, Ph.D., Kansas State University, 141 Chalmers Hall, 1711 Claflin Road, Manhattan, KS 66506, PH: 785.532.3154,
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5
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Le Huyen KB, Gonzalez CD, Pascreau G, Bordeau V, Cattoir V, Liu W, Bouloc P, Felden B, Chabelskaya S. A small regulatory RNA alters Staphylococcus aureus virulence by titrating RNAIII activity. Nucleic Acids Res 2021; 49:10644-10656. [PMID: 34554192 PMCID: PMC8501977 DOI: 10.1093/nar/gkab782] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 08/25/2021] [Accepted: 09/02/2021] [Indexed: 01/17/2023] Open
Abstract
Staphylococcus aureus is an opportunistic human and animal pathogen with an arsenal of virulence factors that are tightly regulated during bacterial infection. The latter is achieved through a sophisticated network of regulatory proteins and regulatory RNAs. Here, we describe the involvement of a novel prophage-carried small regulatory S. aureus RNA, SprY, in the control of virulence genes. An MS2-affinity purification assay reveals that SprY forms a complex in vivo with RNAIII, a major regulator of S. aureus virulence genes. SprY binds to the 13th stem-loop of RNAIII, a key functional region involved in the repression of multiple mRNA targets. mRNAs encoding the repressor of toxins Rot and the extracellular complement binding protein Ecb are among the targets whose expression is increased by SprY binding to RNAIII. Moreover, SprY decreases S. aureus hemolytic activity and virulence. Our results indicate that SprY titrates RNAIII activity by targeting a specific stem loop. Thus, we demonstrate that a prophage-encoded sRNA reduces the pathogenicity of S. aureus through RNA sponge activity.
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Affiliation(s)
- Kim Boi Le Huyen
- Inserm, BRM [Bacterial Regulatory RNAs and Medicine] - UMR_S 1230, 35033 Rennes, France
| | | | - Gaëtan Pascreau
- Inserm, BRM [Bacterial Regulatory RNAs and Medicine] - UMR_S 1230, 35033 Rennes, France
| | - Valérie Bordeau
- Inserm, BRM [Bacterial Regulatory RNAs and Medicine] - UMR_S 1230, 35033 Rennes, France
| | - Vincent Cattoir
- Inserm, BRM [Bacterial Regulatory RNAs and Medicine] - UMR_S 1230, 35033 Rennes, France
| | - Wenfeng Liu
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Philippe Bouloc
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Brice Felden
- Inserm, BRM [Bacterial Regulatory RNAs and Medicine] - UMR_S 1230, 35033 Rennes, France
| | - Svetlana Chabelskaya
- Inserm, BRM [Bacterial Regulatory RNAs and Medicine] - UMR_S 1230, 35033 Rennes, France
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6
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Wahid AA, Dunphy RW, Macpherson A, Gibson BG, Kulik L, Whale K, Back C, Hallam TM, Alkhawaja B, Martin RL, Meschede I, Laabei M, Lawson ADG, Holers VM, Watts AG, Crennell SJ, Harris CL, Marchbank KJ, van den Elsen JMH. Insights Into the Structure-Function Relationships of Dimeric C3d Fragments. Front Immunol 2021; 12:714055. [PMID: 34434196 PMCID: PMC8381054 DOI: 10.3389/fimmu.2021.714055] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 07/21/2021] [Indexed: 11/13/2022] Open
Abstract
Cleavage of C3 to C3a and C3b plays a central role in the generation of complement-mediated defences. Although the thioester-mediated surface deposition of C3b has been well-studied, fluid phase dimers of C3 fragments remain largely unexplored. Here we show C3 cleavage results in the spontaneous formation of C3b dimers and present the first X-ray crystal structure of a disulphide-linked human C3d dimer. Binding studies reveal these dimers are capable of crosslinking complement receptor 2 and preliminary cell-based analyses suggest they could modulate B cell activation to influence tolerogenic pathways. Altogether, insights into the physiologically-relevant functions of C3d(g) dimers gained from our findings will pave the way to enhancing our understanding surrounding the importance of complement in the fluid phase and could inform the design of novel therapies for immune system disorders in the future.
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Affiliation(s)
- Ayla A. Wahid
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Rhys W. Dunphy
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Alex Macpherson
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
- UCB Pharma, Slough, United Kingdom
| | - Beth G. Gibson
- Translational and Clinical Research Institute, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Liudmila Kulik
- Division of Rheumatology, University of Colorado, Aurora, CO, United States
| | | | - Catherine Back
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Thomas M. Hallam
- Translational and Clinical Research Institute, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Bayan Alkhawaja
- Department of Pharmacy and Pharmacology, University of Bath, Bath, United Kingdom
| | - Rebecca L. Martin
- Department of Pharmacy and Pharmacology, University of Bath, Bath, United Kingdom
| | | | - Maisem Laabei
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | | | - V. Michael Holers
- Division of Rheumatology, University of Colorado, Aurora, CO, United States
| | - Andrew G. Watts
- Department of Pharmacy and Pharmacology, University of Bath, Bath, United Kingdom
- Centre for Therapeutic Innovation, University of Bath, Bath, United Kingdom
| | - Susan J. Crennell
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Claire L. Harris
- Translational and Clinical Research Institute, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Kevin J. Marchbank
- Translational and Clinical Research Institute, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Jean M. H. van den Elsen
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
- Centre for Therapeutic Innovation, University of Bath, Bath, United Kingdom
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7
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Knowles A, Campbell S, Cross N, Stafford P. Bacterial Manipulation of the Integrated Stress Response: A New Perspective on Infection. Front Microbiol 2021; 12:645161. [PMID: 33967983 PMCID: PMC8100032 DOI: 10.3389/fmicb.2021.645161] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 02/16/2021] [Indexed: 11/13/2022] Open
Abstract
Host immune activation forms a vital line of defence against bacterial pathogenicity. However, just as hosts have evolved immune responses, bacteria have developed means to escape, hijack and subvert these responses to promote survival. In recent years, a highly conserved group of signalling cascades within the host, collectively termed the integrated stress response (ISR), have become increasingly implicated in immune activation during bacterial infection. Activation of the ISR leads to a complex web of cellular reprogramming, which ultimately results in the paradoxical outcomes of either cellular homeostasis or cell death. Therefore, any pathogen with means to manipulate this pathway could induce a range of cellular outcomes and benefit from favourable conditions for long-term survival and replication. This review aims to outline what is currently known about bacterial manipulation of the ISR and present key hypotheses highlighting areas for future research.
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Affiliation(s)
- Alex Knowles
- Biomolecular Sciences Research Centre, Department of Biosciences and Chemistry, Faculty of Health and Wellbeing, Sheffield Hallam University, Sheffield, United Kingdom
| | - Susan Campbell
- Biomolecular Sciences Research Centre, Department of Biosciences and Chemistry, Faculty of Health and Wellbeing, Sheffield Hallam University, Sheffield, United Kingdom
| | - Neil Cross
- Biomolecular Sciences Research Centre, Department of Biosciences and Chemistry, Faculty of Health and Wellbeing, Sheffield Hallam University, Sheffield, United Kingdom
| | - Prachi Stafford
- Biomolecular Sciences Research Centre, Department of Biosciences and Chemistry, Faculty of Health and Wellbeing, Sheffield Hallam University, Sheffield, United Kingdom
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8
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de Morais SD, Kak G, Menousek JP, Kielian T. Immunopathogenesis of Craniotomy Infection and Niche-Specific Immune Responses to Biofilm. Front Immunol 2021; 12:625467. [PMID: 33708216 PMCID: PMC7940520 DOI: 10.3389/fimmu.2021.625467] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/05/2021] [Indexed: 02/06/2023] Open
Abstract
Bacterial infections in the central nervous system (CNS) can be life threatening and often impair neurological function. Biofilm infection is a complication following craniotomy, a neurosurgical procedure that involves the removal and replacement of a skull fragment (bone flap) to access the brain for surgical intervention. The incidence of infection following craniotomy ranges from 1% to 3% with approximately half caused by Staphylococcus aureus (S. aureus). These infections present a significant therapeutic challenge due to the antibiotic tolerance of biofilm and unique immune properties of the CNS. Previous studies have revealed a critical role for innate immune responses during S. aureus craniotomy infection. Experiments using knockout mouse models have highlighted the importance of the pattern recognition receptor Toll-like receptor 2 (TLR2) and its adaptor protein MyD88 for preventing S. aureus outgrowth during craniotomy biofilm infection. However, neither molecule affected bacterial burden in a mouse model of S. aureus brain abscess highlighting the distinctions between immune regulation of biofilm vs. planktonic infection in the CNS. Furthermore, the immune responses elicited during S. aureus craniotomy infection are distinct from biofilm infection in the periphery, emphasizing the critical role for niche-specific factors in dictating S. aureus biofilm-leukocyte crosstalk. In this review, we discuss the current knowledge concerning innate immunity to S. aureus craniotomy biofilm infection, compare this to S. aureus biofilm infection in the periphery, and discuss the importance of anatomical location in dictating how biofilm influences inflammatory responses and its impact on bacterial clearance.
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Affiliation(s)
- Sharon Db de Morais
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Gunjan Kak
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Joseph P Menousek
- Department of Neurosurgery, University of Nebraska Medical Center, Omaha, NE, United States
| | - Tammy Kielian
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, United States
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9
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Minasyan H, Flachsbart F. Blood coagulation: a powerful bactericidal mechanism of human innate immunity. Int Rev Immunol 2019; 38:3-17. [DOI: 10.1080/08830185.2018.1533009] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Hayk Minasyan
- Private laboratory, Immunology Microbiology, Yerevan, Armenia
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10
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Buchan KD, Foster SJ, Renshaw SA. Staphylococcus aureus: setting its sights on the human innate immune system. MICROBIOLOGY-SGM 2019; 165:367-385. [PMID: 30625113 DOI: 10.1099/mic.0.000759] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Staphylococcus aureus has colonized humans for at least 10 000 years, and today inhabits roughly a third of the population. In addition, S. aureus is a major pathogen that is responsible for a significant disease burden, ranging in severity from mild skin and soft-tissue infections to life-threatening endocarditis and necrotizing pneumonia, with treatment often hampered by resistance to commonly available antibiotics. Underpinning its versatility as a pathogen is its ability to evade the innate immune system. S. aureus specifically targets innate immunity to establish and sustain infection, utilizing a large repertoire of virulence factors to do so. Using these factors, S. aureus can resist phagosomal killing, impair complement activity, disrupt cytokine signalling and target phagocytes directly using proteolytic enzymes and cytolytic toxins. Although most of these virulence factors are well characterized, their importance during infection is less clear, as many display species-specific activity against humans or against animal hosts, including cows, horses and chickens. Several staphylococcal virulence factors display species specificity for components of the human innate immune system, with as few as two amino acid changes reducing binding affinity by as much as 100-fold. This represents a major issue for studying their roles during infection, which cannot be examined without the use of humanized infection models. This review summarizes the major factors S. aureus uses to impair the innate immune system, and provides an in-depth look into the host specificity of S. aureus and how this problem is being approached.
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Affiliation(s)
- Kyle D Buchan
- 1The Bateson Centre and Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Simon J Foster
- 2Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Stephen A Renshaw
- 1The Bateson Centre and Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
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11
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Ivain L, Bordeau V, Eyraud A, Hallier M, Dreano S, Tattevin P, Felden B, Chabelskaya S. An in vivo reporter assay for sRNA-directed gene control in Gram-positive bacteria: identifying a novel sRNA target in Staphylococcus aureus. Nucleic Acids Res 2017; 45:4994-5007. [PMID: 28369640 PMCID: PMC5416835 DOI: 10.1093/nar/gkx190] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 03/11/2017] [Indexed: 12/15/2022] Open
Abstract
Bacterial small regulatory RNAs (sRNAs) play a major role in the regulation of various cellular functions. Most sRNAs interact with mRNA targets via an antisense mechanism, modifying their translation and/or degradation. Despite considerable progresses in discovering sRNAs in Gram-positive bacteria, their functions, for the most part, are unknown. This is mainly due to difficulties in identifying their targets. To aid in the identification of sRNA targets in Gram-positive bacteria, we set up an in vivo method for fast analysis of sRNA-mediated post-transcriptional control at the 5΄ regions of target mRNAs. The technology is based on the co-expression of an sRNA and a 5΄ sequence of an mRNA target fused to a green fluorescent protein (GFP) reporter. The system was challenged on Staphylococcus aureus, an opportunistic Gram-positive pathogen. We analyzed several established sRNA–mRNA interactions, and in addition, we identified the ecb mRNA as a novel target for SprX2 sRNA. Using our in vivo system in combination with in vitro experiments, we demonstrated that SprX2 uses an antisense mechanism to prevent ecb mRNA translation initiation. Furthermore, we used our reporter assay to validate sRNA regulations in other Gram-positive organisms, Bacillus subtilis and Listeria monocytogenes. Overall, our method is broadly applicable to challenge the predicted sRNA–mRNA interactions in Gram-positive bacteria.
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Affiliation(s)
- Lorraine Ivain
- Université de Rennes 1, Inserm U1230-UPRES EA 2311, Biochimie Pharmaceutique, Regulatory RNA and Medicine (RMM), 2 avenue du Prof. Léon Bernard, 35043 Rennes, France
| | - Valérie Bordeau
- Université de Rennes 1, Inserm U1230-UPRES EA 2311, Biochimie Pharmaceutique, Regulatory RNA and Medicine (RMM), 2 avenue du Prof. Léon Bernard, 35043 Rennes, France
| | - Alex Eyraud
- Université de Rennes 1, Inserm U1230-UPRES EA 2311, Biochimie Pharmaceutique, Regulatory RNA and Medicine (RMM), 2 avenue du Prof. Léon Bernard, 35043 Rennes, France
| | - Marc Hallier
- Université de Rennes 1, Inserm U1230-UPRES EA 2311, Biochimie Pharmaceutique, Regulatory RNA and Medicine (RMM), 2 avenue du Prof. Léon Bernard, 35043 Rennes, France
| | - Stéphane Dreano
- Université de Rennes 1, CNRS UMR 6290 IGDR, BIOSIT, Molecular Bases of Tumorigenesis: VHL Disease Team, 35043 Rennes, France
| | - Pierre Tattevin
- Université de Rennes 1, Inserm U1230-UPRES EA 2311, Biochimie Pharmaceutique, Regulatory RNA and Medicine (RMM), 2 avenue du Prof. Léon Bernard, 35043 Rennes, France
| | - Brice Felden
- Université de Rennes 1, Inserm U1230-UPRES EA 2311, Biochimie Pharmaceutique, Regulatory RNA and Medicine (RMM), 2 avenue du Prof. Léon Bernard, 35043 Rennes, France
| | - Svetlana Chabelskaya
- Université de Rennes 1, Inserm U1230-UPRES EA 2311, Biochimie Pharmaceutique, Regulatory RNA and Medicine (RMM), 2 avenue du Prof. Léon Bernard, 35043 Rennes, France
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12
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Amdahl H, Haapasalo K, Tan L, Meri T, Kuusela PI, van Strijp JA, Rooijakkers S, Jokiranta TS. Staphylococcal protein Ecb impairs complement receptor-1 mediated recognition of opsonized bacteria. PLoS One 2017; 12:e0172675. [PMID: 28273167 PMCID: PMC5342210 DOI: 10.1371/journal.pone.0172675] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 02/08/2017] [Indexed: 01/01/2023] Open
Abstract
Staphyloccus aureus is a major human pathogen leading frequently to sepsis and soft tissue infections with abscesses. Multiple virulence factors including several immune modulating molecules contribute to its survival in the host. When S. aureus invades the human body, one of the first line defenses is the complement system, which opsonizes the bacteria with C3b and attract neutrophils by release of chemotactic peptides. Neutrophils express Complement receptor-1 [CR1, CD35) that interacts with the C3b-opsonized particles and thereby plays an important role in pathogen recognition by phagocytic cells. In this study we observed that a fraction of S. aureus culture supernatant prevented binding of C3b to neutrophils. This fraction consisted of S. aureus leukocidins and Efb. The C-terminus of Efb is known to bind C3b and shares significant sequence homology to the extracellular complement binding protein [Ecb). Here we show that S. aureus Ecb displays various mechanisms to block bacterial recognition by neutrophils. The presence of Ecb blocked direct interaction between soluble CR1 and C3b and reduced the cofactor activity of CR1 in proteolytic inactivation of C3b. Furthermore, Ecb could dose-dependently prevent recognition of C3b by cell-bound CR1 that lead to impaired phagocytosis of NHS-opsonized S. aureus. Phagocytosis was furthermore reduced in the presence of soluble CR1 [sCR1). These data indicate that the staphylococcal protein Ecb prevents recognition of C3b opsonized bacteria by neutrophil CR1 leading to impaired killing by phagocytosis and thereby contribute to immune evasion of S. aureus.
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Affiliation(s)
- Hanne Amdahl
- Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki, Helsinki, Finland
- Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
| | - Karita Haapasalo
- Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki, Helsinki, Finland
- Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
| | - Lydia Tan
- Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Taru Meri
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Pentti I. Kuusela
- Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki, Helsinki, Finland
- Division of Clinical Microbiology, Helsinki University Central Hospital Laboratory, Helsinki, Finland
| | - Jos A. van Strijp
- Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Suzan Rooijakkers
- Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
- * E-mail: (SR); (TSJ)
| | - T. Sakari Jokiranta
- Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki, Helsinki, Finland
- Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
- * E-mail: (SR); (TSJ)
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13
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Hovingh ES, van den Broek B, Jongerius I. Hijacking Complement Regulatory Proteins for Bacterial Immune Evasion. Front Microbiol 2016; 7:2004. [PMID: 28066340 PMCID: PMC5167704 DOI: 10.3389/fmicb.2016.02004] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 11/30/2016] [Indexed: 12/11/2022] Open
Abstract
The human complement system plays an important role in the defense against invading pathogens, inflammation and homeostasis. Invading microbes, such as bacteria, directly activate the complement system resulting in the formation of chemoattractants and in effective labeling of the bacteria for phagocytosis. In addition, formation of the membrane attack complex is responsible for direct killing of Gram-negative bacteria. In turn, bacteria have evolved several ways to evade complement activation on their surface in order to be able to colonize and invade the human host. One important mechanism of bacterial escape is attraction of complement regulatory proteins to the microbial surface. These molecules are present in the human body for tight regulation of the complement system to prevent damage to host self-surfaces. Therefore, recruitment of complement regulatory proteins to the bacterial surface results in decreased complement activation on the microbial surface which favors bacterial survival. This review will discuss recent advances in understanding the binding of complement regulatory proteins to the bacterial surface at the molecular level. This includes, new insights that have become available concerning specific conserved motives on complement regulatory proteins that are favorable for microbial binding. Finally, complement evasion molecules are of high importance for vaccine development due to their dominant role in bacterial survival, high immunogenicity and homology as well as their presence on the bacterial surface. Here, the use of complement evasion molecules for vaccine development will be discussed.
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Affiliation(s)
- Elise S. Hovingh
- Department of Medical Microbiology, University Medical Center UtrechtUtrecht, Netherlands
- Centre for Infectious Disease Control, National Institute for Public Health and the EnvironmentBilthoven, Netherlands
| | - Bryan van den Broek
- Department of Medical Microbiology, University Medical Center UtrechtUtrecht, Netherlands
| | - Ilse Jongerius
- Department of Medical Microbiology, University Medical Center UtrechtUtrecht, Netherlands
- Centre for Infectious Disease Control, National Institute for Public Health and the EnvironmentBilthoven, Netherlands
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14
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Ricklin D, Reis ES, Mastellos DC, Gros P, Lambris JD. Complement component C3 - The "Swiss Army Knife" of innate immunity and host defense. Immunol Rev 2016; 274:33-58. [PMID: 27782325 PMCID: PMC5427221 DOI: 10.1111/imr.12500] [Citation(s) in RCA: 265] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
As a preformed defense system, complement faces a delicate challenge in providing an immediate, forceful response to pathogens even at first encounter, while sparing host cells in the process. For this purpose, it engages a tightly regulated network of plasma proteins, cell surface receptors, and regulators. Complement component C3 plays a particularly versatile role in this process by keeping the cascade alert, acting as a point of convergence of activation pathways, fueling the amplification of the complement response, exerting direct effector functions, and helping to coordinate downstream immune responses. In recent years, it has become evident that nature engages the power of C3 not only to clear pathogens but also for a variety of homeostatic processes ranging from tissue regeneration and synapse pruning to clearing debris and controlling tumor cell progression. At the same time, its central position in immune surveillance makes C3 a target for microbial immune evasion and, if improperly engaged, a trigger point for various clinical conditions. In our review, we look at the versatile roles and evolutionary journey of C3, discuss new insights into the molecular basis for C3 function, provide examples of disease involvement, and summarize the emerging potential of C3 as a therapeutic target.
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Affiliation(s)
- Daniel Ricklin
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | - Edimara S Reis
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Dimitrios C Mastellos
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
- National Center for Scientific Research 'Demokritos', Athens, Greece
| | - Piet Gros
- Utrecht University, Utrecht, The Netherlands
| | - John D Lambris
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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15
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Li X, Liu P, Gan S, Zhang C, Zheng Y, Jiang Y, Yuan Y. Mechanisms of Host-Pathogen Protein Complex Formation and Bacterial Immune Evasion of Streptococcus suis Protein Fhb. J Biol Chem 2016; 291:17122-32. [PMID: 27342778 DOI: 10.1074/jbc.m116.719443] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Indexed: 12/26/2022] Open
Abstract
Streptococcus suis serotype 2 (S. suis 2)-induced sepsis and meningitis are often accompanied by bacteremia. The evasion of polymorphonuclear leukocyte-mediated phagocytic clearance is central to the establishment of bacteremia caused by S. suis 2 and is facilitated by the ability of factor H (FH)-binding protein (Fhb) to bind FH on the bacterial surface, thereby impeding alternative pathway complement activation and phagocytic clearance. Here, C3b/C3d was found to bind to Fhb, along with FH, forming a large immune complex. The formation of this immune complex was mediated by domain II of Fhb via electrostatic and hydrophobic interactions, which, to our knowledge, is a new type of interaction. Interestingly, Fhb was found to be associated with the cell envelope and also present in the culture supernatant, where secreted Fhb inhibited complement activation via interactions with domain II, thereby enhancing antiphagocytic clearance by polymorphonuclear leukocytes. Thus, Fhb is a multifunctional bacterial protein, which binds host complement component C3 as well as FH and interferes with innate immune recognition in a secret protein manner. S. suis 2 therefore appears to have developed a new strategy to combat host innate immunity and enhance survival in host blood.
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Affiliation(s)
- Xueqin Li
- From the State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071 and the Central Laboratory of Yijishan Hospital, Wannan Medical College, Wuhu 241001, China
| | - Peng Liu
- From the State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071 and
| | - Shuzhen Gan
- From the State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071 and
| | - Chunmao Zhang
- From the State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071 and
| | - Yuling Zheng
- From the State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071 and
| | - Yongqiang Jiang
- From the State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071 and
| | - Yuan Yuan
- From the State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071 and
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16
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Sass LA, Hair PS, Perkins AM, Shah TA, Krishna NK, Cunnion KM. Complement Effectors of Inflammation in Cystic Fibrosis Lung Fluid Correlate with Clinical Measures of Disease. PLoS One 2015; 10:e0144723. [PMID: 26642048 PMCID: PMC4671727 DOI: 10.1371/journal.pone.0144723] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 11/23/2015] [Indexed: 01/28/2023] Open
Abstract
In cystic fibrosis (CF), lung damage is mediated by a cycle of obstruction, infection, and inflammation. Here we explored complement inflammatory effectors in CF lung fluid. In this study soluble fractions (sols) from sputum samples of 15 CF patients were assayed for complement effectors and analyzed with clinical measurements. The pro-inflammatory peptide C5a was increased 4.8-fold (P = 0.04) in CF sols compared with controls. Incubation of CF sols with P. aeruginosa or S. aureus increased C5a concentration 2.3-fold (P = 0.02). A peptide inhibitor of complement C1 (PIC1) completely blocked the increase in C5a concentration from P. aeruginosa in CF sol in vitro (P = 0.001). C5a concentration in CF sol correlated inversely with body mass index (BMI) percentile in children (r = -0.77, P = 0.04). C3a, which has anti-inflammatory effects, correlated positively with FEV1% predicted (rs = 0.63, P = 0.02). These results suggest that complement effectors may significantly impact inflammation in CF lung fluid.
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Affiliation(s)
- Laura A. Sass
- Department of Pediatrics, Eastern Virginia Medical School, 700 West Olney Road, Norfolk, Virginia, United States of America
- Children's Specialty Group, 811 Redgate Avenue, Norfolk, Virginia, United States of America
- Children’s Hospital of The King’s Daughters, 601 Children’s Lane, Norfolk, Virginia, United States of America
| | - Pamela S. Hair
- Department of Pediatrics, Eastern Virginia Medical School, 700 West Olney Road, Norfolk, Virginia, United States of America
| | - Amy M. Perkins
- Department of Pediatrics, Eastern Virginia Medical School, 700 West Olney Road, Norfolk, Virginia, United States of America
- Children’s Hospital of The King’s Daughters, 601 Children’s Lane, Norfolk, Virginia, United States of America
| | - Tushar A. Shah
- Department of Pediatrics, Eastern Virginia Medical School, 700 West Olney Road, Norfolk, Virginia, United States of America
- Children's Specialty Group, 811 Redgate Avenue, Norfolk, Virginia, United States of America
- Children’s Hospital of The King’s Daughters, 601 Children’s Lane, Norfolk, Virginia, United States of America
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, 700 West Olney Road, Norfolk, Virginia, United States of America
| | - Neel K. Krishna
- Department of Pediatrics, Eastern Virginia Medical School, 700 West Olney Road, Norfolk, Virginia, United States of America
- Children's Specialty Group, 811 Redgate Avenue, Norfolk, Virginia, United States of America
| | - Kenji M. Cunnion
- Department of Pediatrics, Eastern Virginia Medical School, 700 West Olney Road, Norfolk, Virginia, United States of America
- Children's Specialty Group, 811 Redgate Avenue, Norfolk, Virginia, United States of America
- Children’s Hospital of The King’s Daughters, 601 Children’s Lane, Norfolk, Virginia, United States of America
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, 700 West Olney Road, Norfolk, Virginia, United States of America
- * E-mail:
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17
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Thammavongsa V, Kim HK, Missiakas D, Schneewind O. Staphylococcal manipulation of host immune responses. Nat Rev Microbiol 2015; 13:529-43. [PMID: 26272408 DOI: 10.1038/nrmicro3521] [Citation(s) in RCA: 368] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Staphylococcus aureus, a bacterial commensal of the human nares and skin, is a frequent cause of soft tissue and bloodstream infections. A hallmark of staphylococcal infections is their frequent recurrence, even when treated with antibiotics and surgical intervention, which demonstrates the bacterium's ability to manipulate innate and adaptive immune responses. In this Review, we highlight how S. aureus virulence factors inhibit complement activation, block and destroy phagocytic cells and modify host B cell and T cell responses, and we discuss how these insights might be useful for the development of novel therapies against infections with antibiotic resistant strains such as methicillin-resistant S. aureus.
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Affiliation(s)
- Vilasack Thammavongsa
- 1] Department of Microbiology, University of Chicago, 920 East 58th Street, Chicago, Illinois 60637, USA. [2] Regeneron Pharmaceuticals, 755 Old Saw Mill River Road, Tarrytown, New York 10591, USA
| | - Hwan Keun Kim
- Department of Microbiology, University of Chicago, 920 East 58th Street, Chicago, Illinois 60637, USA
| | - Dominique Missiakas
- Department of Microbiology, University of Chicago, 920 East 58th Street, Chicago, Illinois 60637, USA
| | - Olaf Schneewind
- Department of Microbiology, University of Chicago, 920 East 58th Street, Chicago, Illinois 60637, USA
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18
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Aribi M, Meziane W, Habi S, Boulatika Y, Marchandin H, Aymeric JL. Macrophage Bactericidal Activities against Staphylococcus aureus Are Enhanced In Vivo by Selenium Supplementation in a Dose-Dependent Manner. PLoS One 2015; 10:e0135515. [PMID: 26340099 PMCID: PMC4560415 DOI: 10.1371/journal.pone.0135515] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Accepted: 07/22/2015] [Indexed: 11/27/2022] Open
Abstract
Background Dietary selenium is of fundamental importance to maintain optimal immune function and enhance immunity during infection. To this end, we examined the effect of selenium on macrophage bactericidal activities against Staphylococcus aureus. Methods Assays were performed in golden Syrian hamsters and peritoneal macrophages cultured with S. aureus and different concentrations of selenium. Results Infected and selenium-supplemented animals have significantly decreased levels of serum nitric oxide (NO) production when compared with infected but non-selenium-supplemented animals at day 7 post-infection (p < 0.05). A low dose of 5 ng/mL selenium induced a significant decrease in macrophage NO production, but significant increase in hydrogen peroxide (H2O2) levels (respectively, p = 0.009, p < 0.001). The NO production and H2O2 levels were significantly increased with increasing concentrations of selenium; the optimal macrophage activity levels were reached at 20 ng/mL. The concentration of 5 ng/mL of selenium induced a significant decrease in the bacterial arginase activity but a significant increase in the macrophage arginase activity. The dose of 20 ng/mL selenium induced a significant decrease of bacterial growth (p < 0.0001) and a significant increase in macrophage phagocytic activity, NO production/arginase balance and S. aureus killing (for all comparisons, p < 0.001). Conclusions Selenium acts in a dose-dependent manner on macrophage activation, phagocytosis and bacterial killing suggesting that inadequate doses may cause a loss of macrophage bactericidal activities and that selenium supplementation could enhance the in vivo control of immune response to S. aureus.
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Affiliation(s)
- Mourad Aribi
- Laboratory of Applied Molecular Biology and Immunology, Department of Biology, University of Tlemcen, 13000, Tlemcen, Algeria
- * E-mail:
| | - Warda Meziane
- Laboratory of Applied Molecular Biology and Immunology, Department of Biology, University of Tlemcen, 13000, Tlemcen, Algeria
| | - Salim Habi
- Laboratory of Applied Molecular Biology and Immunology, Department of Biology, University of Tlemcen, 13000, Tlemcen, Algeria
| | - Yasser Boulatika
- Laboratory of Applied Molecular Biology and Immunology, Department of Biology, University of Tlemcen, 13000, Tlemcen, Algeria
| | - Hélène Marchandin
- Université Montpellier 1, UMR 5569 HydroSciences Montpellier, Équipe Pathogènes Hydriques Santé Environnements, 34093, Montpellier, Cedex 5, France
- Centre Hospitalier Régional Universitaire, Laboratoire de Bactériologie, 34295, Montpellier, Cedex 5, France
| | - Jean-Luc Aymeric
- UM2-INRA, UMR1333, Laboratoire Diversité, Génomes et Interactions Microorganismes Insectes, Université de Montpellier, Bataillon, 34095, Montpellier, Cedex 05, France
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19
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Evasion and interactions of the humoral innate immune response in pathogen invasion, autoimmune disease, and cancer. Clin Immunol 2015; 160:244-54. [PMID: 26145788 DOI: 10.1016/j.clim.2015.06.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 06/22/2015] [Accepted: 06/26/2015] [Indexed: 02/07/2023]
Abstract
The humoral innate immune system is composed of three major branches, complement, coagulation, and natural antibodies. To persist in the host, pathogens, such as bacteria, viruses, and cancers must evade parts of the innate humoral immune system. Disruptions in the humoral innate immune system also play a role in the development of autoimmune diseases. This review will examine how Gram positive bacteria, viruses, cancer, and the autoimmune conditions systemic lupus erythematosus and anti-phospholipid syndrome, interact with these immune system components. Through examining evasion techniques it becomes clear that an interplay between these three systems exists. By exploring the interplay and the evasion/disruption of the humoral innate immune system, we can develop a better understanding of pathogenic infections, cancer, and autoimmune disease development.
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20
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Identification of peptidic inhibitors of the alternative complement pathway based on Staphylococcus aureus SCIN proteins. Mol Immunol 2015; 67:193-205. [PMID: 26052070 DOI: 10.1016/j.molimm.2015.05.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 05/11/2015] [Accepted: 05/13/2015] [Indexed: 12/14/2022]
Abstract
The complement system plays a central role in a number of human inflammatory diseases, and there is a significant need for development of complement-directed therapies. The discovery of an arsenal of anti-complement proteins secreted by the pathogen Staphylococcus aureus brought with it the potential for harnessing the powerful inhibitory properties of these molecules. One such family of inhibitors, the SCINs, interact with a functional "hot-spot" on the surface of C3b. SCINs not only stabilize an inactive form of the alternative pathway (AP) C3 convertase (C3bBb), but also overlap the C3b binding site of complement factors B and H. Here we determined that a conserved Arg residue in SCINs is critical for function of full-length SCIN proteins. Despite this, we also found SCIN-specific differences in the contributions of other residues found at the C3b contact site, which suggested that a more diverse repertoire of residues might be able to recognize this region of C3b. To investigate this possibility, we conducted a phage display screen aimed at identifying SCIN-competitive 12-mer peptides. In total, seven unique sequences were identified and all exhibited direct C3b binding. A subset of these specifically inhibited the AP in assays of complement function. The mechanism of AP inhibition by these peptides was probed through surface plasmon resonance approaches, which revealed that six of the seven peptides disrupted C3bBb formation by interfering with factor B/C3b binding. To our knowledge this study has identified the first small molecules that retain inhibitory properties of larger staphylococcal immune evasion proteins.
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21
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Li MF, Sun L, Li J. Edwardsiella tarda evades serum killing by preventing complement activation via the alternative pathway. FISH & SHELLFISH IMMUNOLOGY 2015; 43:325-329. [PMID: 25575477 DOI: 10.1016/j.fsi.2014.12.037] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 12/01/2014] [Accepted: 12/26/2014] [Indexed: 06/04/2023]
Abstract
Edwardsiella tarda is a Gram-negative bacterium with a broad host range that includes a wide variety of farmed fish as well as humans. E. tarda has long been known to be able to survive in host serum, but the relevant mechanism is unclear. In this study, we investigated the fundamental question, i.e. whether E. tarda activated serum complement or not. We found that (i) when incubated with flounder serum, E. tarda exhibited a high survival rate (87.6%), which was slightly but significantly reduced in the presence of Mg(2+); (ii) E. tarda-incubated serum possessed strong hemolytic activity and bactericidal activity, (iii) compared to the serum incubated with a complement-sensitive laboratory Escherichia coli strain, E. tarda-incubated serum exhibited much less chemotactic activity, (iv) in contrast to the serum incubated with live E. tarda, the serum incubated with heat-inactivated E. tarda exhibited no apparent hemolytic capacity. Taken together, these results indicate for the first time that E. tarda circumvents serum attack by preventing, to a large extent, complement activation via the alternative pathway, and that heat-labile surface structures likely play an essential role in the complement evasion of E. tarda.
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Affiliation(s)
- Mo-fei Li
- Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; Graduate University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Li Sun
- Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China.
| | - Jun Li
- School of Biological Sciences, Lake Superior State University, 650 W. Easterday Ave., Sault Ste Marie, MI 49783, USA.
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22
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Panelius J, Meri S. Complement system in dermatological diseases - fire under the skin. Front Med (Lausanne) 2015; 2:3. [PMID: 25688346 PMCID: PMC4310328 DOI: 10.3389/fmed.2015.00003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 01/09/2015] [Indexed: 12/03/2022] Open
Abstract
The complement system plays a key role in several dermatological diseases. Overactivation, deficiency, or abnormality of the control proteins are often related to a skin disease. Autoimmune mechanisms with autoantibodies and a cytotoxic effect of the complement membrane attack complex on epidermal or vascular cells can cause direct tissue damage and inflammation, e.g., in systemic lupus erythematosus (SLE), phospholipid antibody syndrome, and bullous skin diseases like pemphigoid. By evading complement attack, some microbes like Borrelia spirochetes and staphylococci can persist in the skin and cause prolonged symptoms. In this review, we present the most important skin diseases connected to abnormalities in the function of the complement system. Drugs having an effect on the complement system are also briefly described. On one hand, drugs with free hydroxyl on amino groups (e.g., hydralazine, procainamide) could interact with C4A, C4B, or C3 and cause an SLE-like disease. On the other hand, progress in studies on complement has led to novel anti-complement drugs (recombinant C1-inhibitor and anti-C5 antibody, eculizumab) that could alleviate symptoms in diseases associated with excessive complement activation. The main theme of the manuscript is to show how relevant the complement system is as an immune effector system in contributing to tissue injury and inflammation in a broad range of skin disorders.
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Affiliation(s)
- Jaana Panelius
- Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki , Helsinki , Finland ; Department of Dermatology and Allergology, Skin and Allergy Hospital, Helsinki University Central Hospital , Helsinki , Finland
| | - Seppo Meri
- Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki , Helsinki , Finland ; Huslab, Helsinki University Central Hospital , Helsinki , Finland ; Research Programs Unit, Immunobiology, University of Helsinki , Helsinki , Finland
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23
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Mohan S, Hertweck C, Dudda A, Hammerschmidt S, Skerka C, Hallström T, Zipfel PF. Tuf of Streptococcus pneumoniae is a surface displayed human complement regulator binding protein. Mol Immunol 2014; 62:249-64. [PMID: 25046156 DOI: 10.1016/j.molimm.2014.06.029] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 06/21/2014] [Accepted: 06/23/2014] [Indexed: 11/15/2022]
Abstract
Streptococcus pneumoniae is a Gram-positive bacterium, causing acute sinusitis, otitis media, and severe diseases such as pneumonia, bacteraemia, meningitis and sepsis. Here we identify elongation factor Tu (Tuf) as a new Factor H binding protein of S. pneumoniae. The surface protein PspC which also binds a series of other human immune inhibitors, was the first identified pneumococcal Factor H binding protein of S. pneumoniae. Pneumococcal Tuf, a 55 kDa pneumococcal moonlighting protein which is displayed on the surface of pneumococci, is also located in the cytoplasm and is detected in the culture supernatant. Tuf binds the human complement inhibitors Factor H, FHL-1, CFHR1 and also the proenzyme plasminogen. Factor H and FHL-1 bound to Tuf, retain their complement regulatory activities. Similarly, plasminogen bound to Tuf was accessible for the activator uPA and activated plasmin cleaved the synthetic chromogenic substrate S-2251 as well as the natural substrates fibrinogen and the complement proteins C3 and C3b. Taken together, Tuf of S. pneumoniae is a new multi-functional bacterial virulence factor that helps the pathogen in complement escape and likely also in ECM degradation.
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Affiliation(s)
- Sarbani Mohan
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knöll-Institute, Jena, Germany
| | - Christian Hertweck
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knöll-Institute, Jena, Germany
| | - Antje Dudda
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knöll-Institute, Jena, Germany
| | - Sven Hammerschmidt
- Department Genetics of Microorganisms, Interfaculty Institute for Genetics and Functional Genomics, Ernst Moritz Arndt University, Greifswald, Germany
| | - Christine Skerka
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knöll-Institute, Jena, Germany
| | - Teresia Hallström
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knöll-Institute, Jena, Germany
| | - Peter F Zipfel
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knöll-Institute, Jena, Germany; Faculty of Biology, Friedrich Schiller University, Jena, Germany.
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