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Schneider VAF, Coorens M, Tjeerdsma-van Bokhoven JLM, Posthuma G, van Dijk A, Veldhuizen EJA, Haagsman HP. Imaging the Antistaphylococcal Activity of CATH-2: Mechanism of Attack and Regulation of Inflammatory Response. mSphere 2017; 2:e00370-17. [PMID: 29104934 PMCID: PMC5663982 DOI: 10.1128/msphere.00370-17] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 10/10/2017] [Indexed: 12/22/2022] Open
Abstract
Chicken cathelicidin-2 (CATH-2) is a broad-spectrum antimicrobial host defense peptide (HDP) that may serve as a paradigm for the development of new antimicrobial agents. While previous studies have elucidated the mechanism by which CATH-2 kills Escherichia coli, its mode of action against Gram-positive bacteria remains to be determined. In this study, we explored the underlying antibacterial mechanism of CATH-2 against a methicillin-resistant strain of Staphylococcus aureus and the effect of CATH-2-mediated S. aureus killing on immune activation. Visualization of the antimicrobial activity of CATH-2 against S. aureus with live-imaging confocal microscopy demonstrated that CATH-2 directly binds the bacteria, which is followed by membrane permeabilization and cell shrinkage. Transmission electron microscopy (TEM) studies further showed that CATH-2 initiated pronounced morphological changes of the membrane (mesosome formation) and ribosomal structures (clustering) in a dose-dependent manner. Immunolabeling of these sections demonstrated that CATH-2 binds and passes the bacterial membrane at subminimal bactericidal concentrations (sub-MBCs). Furthermore, competition assays and isothermal titration calorimetry (ITC) analysis provided evidence that CATH-2 directly interacts with lipoteichoic acid and cardiolipin. Finally, stimulation of macrophages with S. aureus and CATH-2 showed that CATH-2 not only kills S. aureus but also has the potential to limit S. aureus-induced inflammation at or above the MBC. Taken together, it is concluded that at sub-MBCs, CATH-2 perturbs the bacterial membrane and subsequently enters the cell and binds intracellular S. aureus components, while at or above the MBC, CATH-2 causes disruption of membrane integrity and inhibits S. aureus-induced macrophage activation. IMPORTANCE Due to the high use of antibiotics in both human and veterinary settings, many bacteria have become resistant to those antibiotics that we so heavily rely on. Methicillin-resistant S. aureus (MRSA) is one of these difficult-to-treat resistant pathogens for which novel antimicrobial therapies will be required in the near future. One novel approach could be the utilization of naturally occurring antimicrobial peptides, such as chicken CATH-2, which have been show to act against a wide variety of bacteria. However, before these peptides can be used clinically, more knowledge of their functions and mechanisms of action is required. In this study, we used live imaging and electron microscopy to visualize in detail how CATH-2 kills S. aureus, and we investigated how CATH-2 affects immune activation by S. aureus. Together, these results give a better understanding of how CATH-2 kills S. aureus and what the potential immunological consequences of this killing can be.
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Affiliation(s)
- Viktoria A. F. Schneider
- Department of Infectious Diseases and Immunology, Division of Molecular Host Defence, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Maarten Coorens
- Department of Infectious Diseases and Immunology, Division of Molecular Host Defence, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Johanna L. M. Tjeerdsma-van Bokhoven
- Department of Infectious Diseases and Immunology, Division of Molecular Host Defence, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - George Posthuma
- Department of Cell Biology, Cell Microscopy Core, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Albert van Dijk
- Department of Infectious Diseases and Immunology, Division of Molecular Host Defence, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Edwin J. A. Veldhuizen
- Department of Infectious Diseases and Immunology, Division of Molecular Host Defence, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Henk P. Haagsman
- Department of Infectious Diseases and Immunology, Division of Molecular Host Defence, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
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Kretschmer D, Hanzelmann D, Peschel A. Lipoprotein immunoproteomics question the potential of Staphylococcus aureus TLR2 agonists as vaccine antigens. Proteomics 2017; 16:2603-2604. [PMID: 27667303 DOI: 10.1002/pmic.201600351] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 09/23/2016] [Indexed: 12/27/2022]
Abstract
Toll-like receptor 2 (TLR2) is regarded as the major innate immunity sensor in infections caused by the Gram-positive bacterial pathogen Staphylococcus aureus. However, previous studies on the roles of TLR2 in S. aureus infections have been elusive and in part contradictory. It has remained particularly unclear if bacterial lipoproteins, the major TLR2 ligands, could serve as antigens with intrinsic adjuvant property for the development of protective vaccines. The study by Vu et al. published in this issue of Proteomics analyzed the antibody and T-cell responses in human sera against major S. aureus lipoproteins. Notably, even lipoproteins released to culture filtrates at similar levels as established immunodominant antigens elicited only very weak or no detectable antibody and T-cell responses, indicating that the potent TLR2-stimulating capacity of S. aureus lipoproteins does not promote and may rather impair robust immune responses so lipoprpteins. Among several potential explanations it is tempting to speculate that the role of TLR2 in S. aureus infections may be more complex and more ambiguous than previously thought. The study of Vu et al. may thus provoke more detailed investigations on the roles of lipoproteins and TLR2 in innate and adaptive immunity against bacterial pathogens.
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Affiliation(s)
- Dorothee Kretschmer
- Infection Biology Department, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, Germany
| | - Dennis Hanzelmann
- Infection Biology Department, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, Germany
| | - Andreas Peschel
- Infection Biology Department, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, Germany.
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Tuffs SW, James DBA, Bestebroer J, Richards AC, Goncheva MI, O’Shea M, Wee BA, Seo KS, Schlievert PM, Lengeling A, van Strijp JA, Torres VJ, Fitzgerald JR. The Staphylococcus aureus superantigen SElX is a bifunctional toxin that inhibits neutrophil function. PLoS Pathog 2017; 13:e1006461. [PMID: 28880920 PMCID: PMC5589267 DOI: 10.1371/journal.ppat.1006461] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 06/09/2017] [Indexed: 12/29/2022] Open
Abstract
Bacterial superantigens (SAgs) cause Vβ-dependent T-cell proliferation leading to immune dysregulation associated with the pathogenesis of life-threatening infections such as toxic shock syndrome, and necrotizing pneumonia. Previously, we demonstrated that staphylococcal enterotoxin-like toxin X (SElX) from Staphylococcus aureus is a classical superantigen that exhibits T-cell activation in a Vβ-specific manner, and contributes to the pathogenesis of necrotizing pneumonia. Here, we discovered that SElX can also bind to neutrophils from human and other mammalian species and disrupt IgG-mediated phagocytosis. Site-directed mutagenesis of the conserved sialic acid-binding motif of SElX abolished neutrophil binding and phagocytic killing, and revealed multiple glycosylated neutrophil receptors for SElX binding. Furthermore, the neutrophil binding-deficient mutant of SElX retained its capacity for T-cell activation demonstrating that SElX exhibits mechanistically independent activities on distinct cell populations associated with acquired and innate immunity, respectively. Finally, we demonstrated that the neutrophil-binding activity rather than superantigenicity is responsible for the SElX-dependent virulence observed in a necrotizing pneumonia rabbit model of infection. Taken together, we report the first example of a SAg, that can manipulate both the innate and adaptive arms of the human immune system during S. aureus pathogenesis. Staphylococcus aureus is a bacterial pathogen responsible for an array of disease types in healthcare and community settings. One of the keys to the success of this pathogen is its ability to subvert the immune system of the host. Here we demonstrate that the superantigen (SAg) staphylococcal enterotoxin-like toxin X (SElX) contributes to immune evasion by inducing unregulated T-cell proliferation, and by inhibition of phagocytosis by neutrophils. We observed that the capacity to bind neutrophils appears to be central to the SElX-dependent toxicity observed in a necrotising pneumonia infection model in rabbits. We report the first example of a staphylococcal SAg with two independent immunomodulatory functions acting on distinct immune cell types.
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Affiliation(s)
- Stephen W. Tuffs
- The Roslin Institute, University of Edinburgh, Easter Bush Campus, Midlothian, Scotland, United States of America
| | - David B. A. James
- Department of Microbiology, New York University School of Medicine, New York, NY, United Kingdom
| | - Jovanka Bestebroer
- Department Medical Microbiology, UMC Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Amy C. Richards
- The Roslin Institute, University of Edinburgh, Easter Bush Campus, Midlothian, Scotland, United States of America
| | - Mariya I. Goncheva
- The Roslin Institute, University of Edinburgh, Easter Bush Campus, Midlothian, Scotland, United States of America
| | - Marie O’Shea
- The Roslin Institute, University of Edinburgh, Easter Bush Campus, Midlothian, Scotland, United States of America
| | - Bryan A. Wee
- The Roslin Institute, University of Edinburgh, Easter Bush Campus, Midlothian, Scotland, United States of America
| | - Keun Seok Seo
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States
| | - Patrick M. Schlievert
- Department of Microbiology, University of Iowa, Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Andreas Lengeling
- The Roslin Institute, University of Edinburgh, Easter Bush Campus, Midlothian, Scotland, United States of America
| | - Jos A. van Strijp
- Department Medical Microbiology, UMC Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Victor J. Torres
- Department of Microbiology, New York University School of Medicine, New York, NY, United Kingdom
| | - J. Ross Fitzgerald
- The Roslin Institute, University of Edinburgh, Easter Bush Campus, Midlothian, Scotland, United States of America
- * E-mail:
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Ohto U. Conservation and Divergence of Ligand Recognition and Signal Transduction Mechanisms in Toll-Like Receptors. Chem Pharm Bull (Tokyo) 2017; 65:697-705. [PMID: 28768923 DOI: 10.1248/cpb.c17-00323] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Toll-like receptors (TLRs) play a central role in innate immunity as pathogen sensors. During the last decade, structural analyses of TLRs have revealed the mechanisms of ligand recognition and signal transduction. Each TLR recognizes its cognate ligand in a different manner, whereas signal transduction is achieved by a common mechanism. In this review, the mechanisms of ligand recognition and signal transduction by TLRs are summarized based on recent structural information.
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Affiliation(s)
- Umeharu Ohto
- Graduate School of Pharmaceutical Sciences, The University of Tokyo
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55
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Hsu SH, Hung CC, Chang MY, Ko YC, Yang HY, Hsu HH, Tian YC, Chou LF, Pan RL, Tseng FG, Yang CW. Active Components of Leptospira Outer Membrane Protein LipL32 to Toll-Like Receptor 2. Sci Rep 2017; 7:8363. [PMID: 28827637 PMCID: PMC5566480 DOI: 10.1038/s41598-017-08743-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 07/17/2017] [Indexed: 01/14/2023] Open
Abstract
Proteins belonging to the toll-like receptor (TLR) family, particularly TLR2, are the major components of innate immunity against Leptospira infection. The ligands for TLR2 harbor several conserved patterns such as lipidation molecules, leucine-rich repeat (LRR) domains, TLR2 binding motifs, and TLR2 binding structure. In Leptospira, LipL32 interacts with TLR2 on human kidney cells concomitantly stimulating inflammatory responses. However, the binding mechanism of LipL32 to TLR2 is unknown. The computational prediction suggests that β1β2, loop-α3-loop, and α4 domains of LipL32 play vital roles in LipL32-TLR2 complex formation. To test these predictions, protein truncation experiments revealed that LipL32ΔNβ1β2 significantly decreased the affinity to TLR2 while LipL32ΔCα4 slightly reduced it. Interestingly, LipL32ΔCenα3 retained affinity to TLR2 in the absence of Ca2+ ions, indicating that Cenα3 play a role preventing the interaction between LipL32 and TLR2. Furthermore, the critical residues of LipL32 involved in interacting with TLR2 suggested that V35S, L36S and L263S variants significantly decreased the affinity to TLR2. The results further confirm that LipL32 interacts with TLR2 through Nβ1β2 and Cα4 domains of LipL32 as well as LipL32-TLR2 complex formation results from hydrophobic interactions. This study provides a detailed mechanism of the interaction between LipL32 and TLR2 and the residues involved in complex formation.
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Affiliation(s)
- Shen-Hsing Hsu
- Department of Nephrology, Kidney Research Center, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, 33333, Taiwan, ROC
| | - Cheng-Chieh Hung
- Department of Nephrology, Kidney Research Center, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, 33333, Taiwan, ROC
| | - Ming-Yang Chang
- Department of Nephrology, Kidney Research Center, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, 33333, Taiwan, ROC
| | - Yi-Ching Ko
- Department of Nephrology, Kidney Research Center, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, 33333, Taiwan, ROC
| | - Huang-Yu Yang
- Department of Nephrology, Kidney Research Center, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, 33333, Taiwan, ROC
| | - Hsiang-Hao Hsu
- Department of Nephrology, Kidney Research Center, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, 33333, Taiwan, ROC
| | - Ya-Chung Tian
- Department of Nephrology, Kidney Research Center, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, 33333, Taiwan, ROC
| | - Li-Fang Chou
- Department of Nephrology, Kidney Research Center, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, 33333, Taiwan, ROC
| | - Rong-Long Pan
- Department of Life Science and Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, Hsin Chu, 30013, Taiwan, ROC
| | - Fan-Gang Tseng
- Department of Engineering and System Science, College of Nuclear Science, National Tsing Hua University, Hsin Chu, 30013, Taiwan, ROC
| | - Chih-Wei Yang
- Department of Nephrology, Kidney Research Center, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, 33333, Taiwan, ROC.
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Durai P, Shin HJ, Achek A, Kwon HK, Govindaraj RG, Panneerselvam S, Yesudhas D, Choi J, No KT, Choi S. Toll-like receptor 2 antagonists identified through virtual screening and experimental validation. FEBS J 2017; 284:2264-2283. [PMID: 28570013 DOI: 10.1111/febs.14124] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 05/08/2017] [Accepted: 05/30/2017] [Indexed: 12/23/2022]
Abstract
Toll-like receptor 2 (TLR2) antagonists are key therapeutic targets because they inhibit several inflammatory diseases caused by surplus TLR2 activation. In this study, we identified two novel nonpeptide TLR2 antagonists, C11 and C13, through pharmacophore-based virtual screening. At 10 μm, the level of interleukin (IL)-8 inhibition by C13 and C11 in human embryonic kidney TLR2 overexpressing cells was comparable to the commercially available TLR2 inhibitor CU-CPT22. In addition, C11 and C13 acted in mouse macrophage-like RAW 264.7 cells as TLR2-specific inhibitors and did not suppress the tumor necrosis factor-α induction by TLR3 and TLR4 activators. Moreover, the two identified compounds bound directly to the human recombinant TLR2 ectodomain, during surface plasmon resonance analysis, and did not affect cell viability in a 3-(4,5-dimethylthiazol-2-yl)-5(3-carboxymethonyphenol)-2-(4-sulfophenyl)-2H-tetrazolium assay. In total, two virtually screened molecules, C11 and C13, were experimentally proven to be effective as TLR2 antagonists, and thus will provide new insights into the structure of TLR2 antagonists, and pave the way for the development of TLR2-targeted drug molecules.
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Affiliation(s)
| | - Hyeon-Jun Shin
- Department of Molecular Science and Technology, Ajou University, Suwon, Korea
| | - Asma Achek
- Department of Molecular Science and Technology, Ajou University, Suwon, Korea
| | - Hyuk-Kwon Kwon
- Department of Molecular Science and Technology, Ajou University, Suwon, Korea
| | | | | | - Dhanusha Yesudhas
- Department of Molecular Science and Technology, Ajou University, Suwon, Korea
| | - Jiwon Choi
- Bioinformatics and Molecular Design Research Center, Seoul, Korea
| | - Kyoung Tai No
- Bioinformatics and Molecular Design Research Center, Seoul, Korea.,Department of Biotechnology, Yonsei University, Seoul, Korea
| | - Sangdun Choi
- Department of Molecular Science and Technology, Ajou University, Suwon, Korea
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57
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Guerra FE, Borgogna TR, Patel DM, Sward EW, Voyich JM. Epic Immune Battles of History: Neutrophils vs. Staphylococcus aureus. Front Cell Infect Microbiol 2017; 7:286. [PMID: 28713774 PMCID: PMC5491559 DOI: 10.3389/fcimb.2017.00286] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 06/12/2017] [Indexed: 12/23/2022] Open
Abstract
Neutrophils are the most abundant leukocytes in human blood and the first line of defense after bacteria have breached the epithelial barriers. After migration to a site of infection, neutrophils engage and expose invading microorganisms to antimicrobial peptides and proteins, as well as reactive oxygen species, as part of their bactericidal arsenal. Ideally, neutrophils ingest bacteria to prevent damage to surrounding cells and tissues, kill invading microorganisms with antimicrobial mechanisms, undergo programmed cell death to minimize inflammation, and are cleared away by macrophages. Staphylococcus aureus (S. aureus) is a prevalent Gram-positive bacterium that is a common commensal and causes a wide range of diseases from skin infections to endocarditis. Since its discovery, S. aureus has been a formidable neutrophil foe that has challenged the efficacy of this professional assassin. Indeed, proper clearance of S. aureus by neutrophils is essential to positive infection outcome, and S. aureus has developed mechanisms to evade neutrophil killing. Herein, we will review mechanisms used by S. aureus to modulate and evade neutrophil bactericidal mechanisms including priming, activation, chemotaxis, production of reactive oxygen species, and resolution of infection. We will also highlight how S. aureus uses sensory/regulatory systems to tailor production of virulence factors specifically to the triggering signal, e.g., neutrophils and defensins. To conclude, we will provide an overview of therapeutic approaches that may potentially enhance neutrophil antimicrobial functions.
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Affiliation(s)
- Fermin E Guerra
- Department of Microbiology and Immunology, Montana State UniversityBozeman, MT, United States
| | - Timothy R Borgogna
- Department of Microbiology and Immunology, Montana State UniversityBozeman, MT, United States
| | - Delisha M Patel
- Department of Microbiology and Immunology, Montana State UniversityBozeman, MT, United States
| | - Eli W Sward
- Department of Microbiology and Immunology, Montana State UniversityBozeman, MT, United States
| | - Jovanka M Voyich
- Department of Microbiology and Immunology, Montana State UniversityBozeman, MT, United States
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58
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Bitschar K, Wolz C, Krismer B, Peschel A, Schittek B. Keratinocytes as sensors and central players in the immune defense against Staphylococcus aureus in the skin. J Dermatol Sci 2017; 87:215-220. [PMID: 28655473 DOI: 10.1016/j.jdermsci.2017.06.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 06/02/2017] [Accepted: 06/07/2017] [Indexed: 02/08/2023]
Abstract
Healthy human skin provides an effective mechanical as well as immunologic barrier against pathogenic microorganisms with keratinocytes as the main cell type in the epidermis actively participating and orchestrating the innate immune response of the skin. As constituent of the outermost layer encountering potential pathogens they have to sense signals from the environment and must be able to initiate a differential immune response to harmless commensals and harmful pathogens. Staphylococci are among the most abundant colonizers of the skin: Whereas Staphylococcus epidermidis is part of the skin microbiota and ubiquitously colonizes human skin, Staphylococcus aureus is only rarely found on healthy human skin, but frequently colonizes the skin of atopic dermatitis (AD) patients. This review highlights recent advances in understanding how keratinocytes as sessile innate immune cells orchestrate an effective defense against S. aureus in healthy skin and the mechanisms leading to an impaired keratinocyte function in AD patients.
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Affiliation(s)
| | - Christiane Wolz
- Interfaculty Institute of Microbiology and Infection Medicine, Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany
| | - Bernhard Krismer
- Interfaculty Institute of Microbiology and Infection Medicine, Infection Biology, University of Tübingen, Tübingen, Germany
| | - Andreas Peschel
- Interfaculty Institute of Microbiology and Infection Medicine, Infection Biology, University of Tübingen, Tübingen, Germany
| | - Birgit Schittek
- Department of Dermatology, University of Tübingen, Tübingen, Germany.
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59
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Nemati M, Larussa T, Khorramdelazad H, Mahmoodi M, Jafarzadeh A. Toll-like receptor 2: An important immunomodulatory molecule during Helicobacter pylori infection. Life Sci 2017; 178:17-29. [PMID: 28427896 DOI: 10.1016/j.lfs.2017.04.006] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 04/06/2017] [Accepted: 04/11/2017] [Indexed: 12/11/2022]
Abstract
Toll like receptors (TLRs) are an essential subset of pathogen recognition receptors (PRRs) which identify the microbial components and contribute in the regulation of innate and adaptive immune responses against the infectious agents. The TLRs, especially TLR2, TLR4, TLR5 and TLR9, participate in the induction of immune response against H. pylori. TLR2 is expressed on a number of immune and non-immune cells and recognizes a vast broad of microbial components due to its potential to form heterodimers with other TLRs, including TLR1, TLR6 and TLR10. A number of H. pylori-related molecules may contribute to TLR2-dependent responses, including HP-LPS, HP-HSP60 and HP-NAP. TLR2 plays a pivotal role in regulation of immune response to H. pylori through activation of NF-κB and induction of cytokine expression in epithelial cells, monocytes/macrophages, dendritic cells, neutrophils and B cells. The TLR2-related immune response that is induced by H. pylori-derived components may play an important role regarding the outcome of the infection toward bacterial elimination, persistence or pathological reactions. The immunomodulatory and immunoregulatory roles of TLR2 during H. pylori infection were considered in this review. TLR2 could be considered as an interesting therapeutic target for treatment of H. pylori-related diseases.
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Affiliation(s)
- Maryam Nemati
- Department of Laboratory Sciences, School of Para-Medicine, Kerman University of Medical Sciences, Kerman, Iran; Department of Microbiology, School of Medicine, Islamic Azad University Branch of Kerman, Kerman, Iran
| | - Tiziana Larussa
- Department of Health Sciences, University of Catanzaro "Magna Graecia", 88100 Catanzaro, Italy
| | - Hossein Khorramdelazad
- Molecular Medicine Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
| | - Merat Mahmoodi
- Department of Immunology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Abdollah Jafarzadeh
- Immunology of Infectious Diseases Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran; Department of Immunology, School of Medicine, Rafsanjan University of Medical Sciences, Rafsanjan, Iran; Department of Immunology, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran.
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Itoh S, Takii T, Onozaki K, Tsuji T, Hida S. Identification of the blood coagulation factor interacting sequences in staphylococcal superantigen-like protein 10. Biochem Biophys Res Commun 2017; 485:201-208. [DOI: 10.1016/j.bbrc.2017.02.053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 02/09/2017] [Indexed: 02/03/2023]
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61
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Neutrophils and Immunity: From Bactericidal Action to Being Conquered. J Immunol Res 2017; 2017:9671604. [PMID: 28299345 PMCID: PMC5337389 DOI: 10.1155/2017/9671604] [Citation(s) in RCA: 136] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 01/29/2017] [Indexed: 12/19/2022] Open
Abstract
The neutrophil is the major phagocyte and the final effector cell of the innate immunity, with a primary role in the clearance of extracellular pathogens. Using the broad array of cytokines, extracellular traps, and effector molecules as the humoral arm, neutrophils play a crucial role in the host defense against pathogen infections. On the other hand, the pathogen has the capacity to overcome neutrophil-mediated host defense to establish infection causing human disease. Pathogens, such as S. aureus, have the potential to thwart neutrophil chemotaxis and phagocytosis and thereby succeed in evading killing by neutrophils. Furthermore, S. aureus surviving within neutrophils promotes neutrophil cytolysis, resulting in the release of host-derived molecules that promote local inflammation. Here, we provide a detailed overview of the mechanisms by which neutrophils kill the extracellular pathogens and how pathogens evade neutrophils degradation. This review will provide insights that might be useful for the development of novel therapies against infections caused by antibiotic resistant pathogens.
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62
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De Buck M, Gouwy M, Wang JM, Van Snick J, Opdenakker G, Struyf S, Van Damme J. Structure and Expression of Different Serum Amyloid A (SAA) Variants and their Concentration-Dependent Functions During Host Insults. Curr Med Chem 2017; 23:1725-55. [PMID: 27087246 PMCID: PMC5405626 DOI: 10.2174/0929867323666160418114600] [Citation(s) in RCA: 156] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 03/31/2016] [Accepted: 04/15/2016] [Indexed: 12/23/2022]
Abstract
Serum amyloid A (SAA) is, like C-reactive protein (CRP), an acute phase protein and can be used as a diagnostic, prognostic or therapy follow-up marker for many diseases. Increases in serum levels of SAA are triggered by physical insults to the host, including infection, trauma, inflammatory reactions and cancer. The order of magnitude of increase in SAA levels varies considerably, from a 10- to 100-fold during limited inflammatory events to a 1000-fold increase during severe bacterial infections and acute exacerbations of chronic inflammatory diseases. This broad response range is reflected by SAA gene duplications resulting in a cluster encoding several SAA variants and by multiple biological functions of SAA. SAA variants are single-domain proteins with simple structures and few post-translational modifications. SAA1 and SAA2 are inducible by inflammatory cytokines, whereas SAA4 is constitutively produced. We review here the regulated expression of SAA in normal and transformed cells and compare its serum levels in various disease states. At low concentrations (10-100 ng/ml), early in an inflammatory response, SAA induces chemokines or matrix degrading enzymes via Toll-like receptors and functions as an activator and chemoattractant through a G protein-coupled receptor. When an infectious or inflammatory stimulus persists, the liver continues to produce more SAA (> 1000 ng/ml) to become an antimicrobial agent by functioning as a direct opsonin of bacteria or by interference with virus infection of host cells. Thus, SAA regulates innate and adaptive immunity and this information may help to design better drugs to treat specific diseases.
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Affiliation(s)
| | | | | | | | | | | | - Jo Van Damme
- University of Leuven, Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Molecular Immunology, Minderbroedersstraat 10, 3000 Leuven, Belgium.
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63
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Balancing Inflammation: Computational Design of Small-Molecule Toll-like Receptor Modulators. Trends Pharmacol Sci 2017; 38:155-168. [DOI: 10.1016/j.tips.2016.10.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 10/10/2016] [Accepted: 10/12/2016] [Indexed: 12/25/2022]
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Pizzuto M, Gangloff M, Scherman D, Gay NJ, Escriou V, Ruysschaert JM, Lonez C. Toll-like receptor 2 promiscuity is responsible for the immunostimulatory activity of nucleic acid nanocarriers. J Control Release 2016; 247:182-193. [PMID: 28040465 PMCID: PMC5312493 DOI: 10.1016/j.jconrel.2016.12.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 12/23/2016] [Indexed: 12/14/2022]
Abstract
Lipopolyamines (LPAs) are cationic lipids; they interact spontaneously with nucleic acids to form lipoplexes used for gene delivery. The main hurdle to using lipoplexes in gene therapy lies in their immunostimulatory properties, so far attributed to the nucleic acid cargo, while cationic lipids were considered as inert to the immune system. Here we demonstrate for the first time that di-C18 LPAs trigger pro-inflammatory responses through Toll-like receptor 2 (TLR2) activation, and this whether they are bound to nucleic acids or not. Molecular docking experiments suggest potential TLR2 binding modes reminiscent of bacterial lipopeptide sensing. The di-C18 LPAs share the ability of burying their lipid chains in the hydrophobic cavity of TLR2 and, in some cases, TLR1, at the vicinity of the dimerization interface; the cationic headgroups form multiple hydrogen bonds, thus crosslinking TLRs into functional complexes. Unravelling the molecular basis of TLR1 and TLR6-driven heterodimerization upon LPA binding underlines the highly collaborative and promiscuous ligand binding mechanism. The prevalence of non-specific main chain-mediated interactions demonstrates that potentially any saturated LPA currently used or proposed as transfection agent is likely to activate TLR2 during transfection. Hence our study emphasizes the urgent need to test the inflammatory properties of transfection agents and proposes the use of docking analysis as a preliminary screening tool for the synthesis of new non-immunostimulatory nanocarriers.
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Affiliation(s)
- Malvina Pizzuto
- Structure and Function of Biological Membranes, Université Libre de Bruxelles, Boulevard du Triomphe, 1050 Brussels, Belgium.
| | - Monique Gangloff
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, UK.
| | - Daniel Scherman
- CNRS, Unité de Technologies Chimiques et Biologiques pour la Santé (UTCBS), UMR 8258, F-75006 Paris, France; INSERM, UTCBS U 1022, F-75006 Paris, France; Université Paris Descartes, Sorbonne-Paris-Cité University, UTCBS, F-75006 Paris, France; Chimie ParisTech, PSL Research University, UTCBS, F-75005 Paris, France
| | - Nicholas J Gay
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, UK
| | - Virginie Escriou
- CNRS, Unité de Technologies Chimiques et Biologiques pour la Santé (UTCBS), UMR 8258, F-75006 Paris, France; INSERM, UTCBS U 1022, F-75006 Paris, France; Université Paris Descartes, Sorbonne-Paris-Cité University, UTCBS, F-75006 Paris, France; Chimie ParisTech, PSL Research University, UTCBS, F-75005 Paris, France
| | - Jean-Marie Ruysschaert
- Structure and Function of Biological Membranes, Université Libre de Bruxelles, Boulevard du Triomphe, 1050 Brussels, Belgium
| | - Caroline Lonez
- Structure and Function of Biological Membranes, Université Libre de Bruxelles, Boulevard du Triomphe, 1050 Brussels, Belgium; Department of Veterinary Medicine, University of Cambridge, Madingley Rd, Cambridge CB3 0ES, UK
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65
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Lipoproteins of Gram-Positive Bacteria: Key Players in the Immune Response and Virulence. Microbiol Mol Biol Rev 2016; 80:891-903. [PMID: 27512100 DOI: 10.1128/mmbr.00028-16] [Citation(s) in RCA: 130] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Since the discovery in 1973 of the first of the bacterial lipoproteins (Lpp) in Escherichia coli, Braun's lipoprotein, the ever-increasing number of publications indicates the importance of these proteins. Bacterial Lpp belong to the class of lipid-anchored proteins that in Gram-negative bacteria are anchored in both the cytoplasmic and outer membranes and in Gram-positive bacteria are anchored only in the cytoplasmic membrane. In contrast to the case for Gram-negative bacteria, in Gram-positive bacteria lipoprotein maturation and processing are not vital. Physiologically, Lpp play an important role in nutrient and ion acquisition, allowing particularly pathogenic species to better survive in the host. Bacterial Lpp are recognized by Toll-like receptor 2 (TLR2) of the innate immune system. The important role of Lpp in Gram-positive bacteria, particularly in the phylum Firmicutes, as key players in the immune response and pathogenicity has emerged only in recent years. In this review, we address the role of Lpp in signaling and modulating the immune response, in inflammation, and in pathogenicity. We also address the potential of Lpp as promising vaccine candidates.
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66
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Hanzelmann D, Joo HS, Franz-Wachtel M, Hertlein T, Stevanovic S, Macek B, Wolz C, Götz F, Otto M, Kretschmer D, Peschel A. Toll-like receptor 2 activation depends on lipopeptide shedding by bacterial surfactants. Nat Commun 2016; 7:12304. [PMID: 27470911 PMCID: PMC4974576 DOI: 10.1038/ncomms12304] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 06/21/2016] [Indexed: 12/18/2022] Open
Abstract
Sepsis caused by Gram-positive bacterial pathogens is a major fatal disease but its molecular basis remains elusive. Toll-like receptor 2 (TLR2) has been implicated in the orchestration of inflammation and sepsis but its role appears to vary for different pathogen species and clones. Accordingly, Staphylococcus aureus clinical isolates differ substantially in their capacity to activate TLR2. Here we show that strong TLR2 stimulation depends on high-level production of phenol-soluble modulin (PSM) peptides in response to the global virulence activator Agr. PSMs are required for mobilizing lipoproteins, the TLR2 agonists, from the staphylococcal cytoplasmic membrane. Notably, the course of sepsis caused by PSM-deficient S. aureus is similar in wild-type and TLR2-deficient mice, but TLR2 is required for protection of mice against PSM-producing S. aureus. Thus, a crucial role of TLR2 depends on agonist release by bacterial surfactants. Modulation of this process may lead to new therapeutic strategies against Gram-positive infections. The role played by human protein TLR2 in inflammation and sepsis varies for different bacterial pathogens. Here, Hanzelmann et al. show that the differential abilities of Staphylococcus aureus strains to activate TLR2 depend on their production of peptides that release lipoproteins known to act as TLR2 agonists.
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Affiliation(s)
- Dennis Hanzelmann
- Department of Infection Biology, Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Mirita Franz-Wachtel
- Proteome Center Tübingen, Interfaculty Institute of Cell Biology, University of Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
| | - Tobias Hertlein
- Institute for Molecular Infection Biology, University of Würzburg, Josef-Schneider-Straße 2, Würzburg 97080, Germany
| | - Stefan Stevanovic
- Department of Immunology, Interfaculty Institute for Cell Biology, Eberhard Karls University, Auf der Morgenstelle 15, 72076 Tübingen, Germany
| | - Boris Macek
- Proteome Center Tübingen, Interfaculty Institute of Cell Biology, University of Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
| | - Christiane Wolz
- Department of Medical Microbiology and Hygiene, Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Friedrich Götz
- Department of Microbial Genetics, Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Dorothee Kretschmer
- Department of Infection Biology, Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany.,German Center for Infection Research, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - Andreas Peschel
- Department of Infection Biology, Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany.,German Center for Infection Research, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
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67
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Koymans KJ, Bisschop A, Vughs MM, van Kessel KPM, de Haas CJC, van Strijp JAG. Staphylococcal Superantigen-Like Protein 1 and 5 (SSL1 & SSL5) Limit Neutrophil Chemotaxis and Migration through MMP-Inhibition. Int J Mol Sci 2016; 17:E1072. [PMID: 27399672 PMCID: PMC4964448 DOI: 10.3390/ijms17071072] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 06/27/2016] [Accepted: 06/28/2016] [Indexed: 12/28/2022] Open
Abstract
Matrix metalloproteinases (MMPs) are endopeptidases that degrade components of the extracellular matrix, but also modulate inflammation. During bacterial infections, MMPs are important in the recruitment and migration of inflammatory cells. Besides facilitating cell migration by degrading extracellular matrix components, they potentiate the action of several inflammatory molecules, including cytokines, chemokines, and antimicrobial peptides. Staphylococcus aureus secretes an arsenal of immune evasion molecules that interfere with immune cell functioning and hamper proper immune responses. An earlier study identified staphylococcal superantigen-like protein 5 (SSL5) as an MMP9 inhibitor. Since multiple MMPs are involved in neutrophil recruitment, we set up an in-depth search for additional MMP inhibitors by testing a panel of over 70 secreted staphylococcal proteins on the inhibition of the two main neutrophil MMPs: MMP8 (neutrophil collagenase) and MMP9 (neutrophil gelatinase B). We identified SSL1 and SSL5 as potent inhibitors of both neutrophil MMPs and show that they are actually broad range MMP inhibitors. SSL1 and SSL5 prevent MMP-induced cleavage and potentiation of IL-8 and inhibit the migration of neutrophils through collagen. Thus, through MMP-inhibition, SSL1 and SSL5 interfere with neutrophil activation, chemotaxis, and migration, all vital neutrophil functions in bacterial clearance. Studies on MMP-SSL interactions can have therapeutic potential and SSL based derivatives might prove useful in treatment of cancer and destructive inflammatory diseases.
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Affiliation(s)
- Kirsten J Koymans
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands.
| | - Adinda Bisschop
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands.
| | - Mignon M Vughs
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands.
| | - Kok P M van Kessel
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands.
| | - Carla J C de Haas
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands.
| | - Jos A G van Strijp
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands.
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68
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Yun Z, Jianping P. [Progress on the role of Toll-like receptors in Candida albicans infections]. Zhejiang Da Xue Xue Bao Yi Xue Ban 2016; 45:302-7. [PMID: 27651197 PMCID: PMC10396928 DOI: 10.3785/j.issn.1008-9292.2016.05.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 01/20/2016] [Indexed: 06/06/2023]
Abstract
Toll like receptors (TLRs) are expressed mainly on innate immunocytes such as dendritic cells and macrophages, and may have the potential to recognize and bind to pathogen-associated molecular patterns (PAMPs) from Candida albicans, thereby triggering the downstream signals. The genetic polymorphism of TLRs is associated with susceptibility to Candida albicans. The activation of TLRs by PAMPs from Candida albicans can induce the production of proinflammatory cytokines that play key roles in the anti-infection of Candida albicans. However, in order to evade the immune response of host,Candida albicans can also change its bacterial phase. Understanding of the interaction between TLRs and Candida albicans will provide novel evidence to further clarify the mechanisms of anti-fungal immune response.
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Affiliation(s)
- Zhou Yun
- Zhejiang University City College School of Medicine, Hangzhou 310015, China;Department of Pathogen Biology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Pan Jianping
- Zhejiang University City College School of Medicine, Hangzhou 310015, China.
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69
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Patra MC, Choi S. Recent progress in the development of Toll-like receptor (TLR) antagonists. Expert Opin Ther Pat 2016; 26:719-30. [DOI: 10.1080/13543776.2016.1185415] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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70
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Xiong XY, Liu L, Yang QW. Functions and mechanisms of microglia/macrophages in neuroinflammation and neurogenesis after stroke. Prog Neurobiol 2016; 142:23-44. [PMID: 27166859 DOI: 10.1016/j.pneurobio.2016.05.001] [Citation(s) in RCA: 464] [Impact Index Per Article: 58.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 04/20/2016] [Accepted: 05/01/2016] [Indexed: 02/08/2023]
Abstract
Microglia/macrophages are the major immune cells involved in the defence against brain damage. Their morphology and functional changes are correlated with the release of danger signals induced by stroke. These cells are normally responsible for clearing away dead neural cells and restoring neuronal functions. However, when excessively activated by the damage-associated molecular patterns following stroke, they can produce a large number of proinflammatory cytokines that can disrupt neural cells and the blood-brain barrier and influence neurogenesis. These effects indicate the important roles of microglia/macrophages in the pathophysiological processes of stroke. However, the modifiable and adaptable nature of microglia/macrophages may also be beneficial for brain repair and not just result in damage. These distinct roles may be attributed to the different microglia/macrophage phenotypes because the M1 population is mainly destructive, while the M2 population is neuroprotective. Additionally, different gene expression signature changes in microglia/macrophages have been found in diverse inflammatory milieus. These biofunctional features enable dual roles for microglia/macrophages in brain damage and repair. Currently, it is thought that the proper inflammatory milieu may provide a suitable microenvironment for neurogenesis; however, detailed mechanisms underlying the inflammatory responses that initiate or inhibit neurogenesis remain unknown. This review summarizes recent progress concerning the mechanisms involved in brain damage, repair and regeneration related to microglia/macrophage activation and phenotype transition after stroke. We also argue that future translational studies should be targeting multiple key regulating molecules to improve brain repair, which should be accompanied by the concept of a "therapeutic time window" for sequential therapies.
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Affiliation(s)
- Xiao-Yi Xiong
- Department of Neurology, Xinqiao Hospital & The Second Affiliated Hospital, The Third Military Medical University, Xinqiao zhengjie No.183, Shapingba District Chongqing, 400037, China
| | - Liang Liu
- Department of Neurology, Xinqiao Hospital & The Second Affiliated Hospital, The Third Military Medical University, Xinqiao zhengjie No.183, Shapingba District Chongqing, 400037, China
| | - Qing-Wu Yang
- Department of Neurology, Xinqiao Hospital & The Second Affiliated Hospital, The Third Military Medical University, Xinqiao zhengjie No.183, Shapingba District Chongqing, 400037, China.
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71
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Koymans KJ, Vrieling M, Gorham RD, van Strijp JAG. Staphylococcal Immune Evasion Proteins: Structure, Function, and Host Adaptation. Curr Top Microbiol Immunol 2015; 409:441-489. [PMID: 26919864 DOI: 10.1007/82_2015_5017] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Staphylococcus aureus is a successful human and animal pathogen. Its pathogenicity is linked to its ability to secrete a large amount of virulence factors. These secreted proteins interfere with many critical components of the immune system, both innate and adaptive, and hamper proper immune functioning. In recent years, numerous studies have been conducted in order to understand the molecular mechanism underlying the interaction of evasion molecules with the host immune system. Structural studies have fundamentally contributed to our understanding of the mechanisms of action of the individual factors. Furthermore, such studies revealed one of the most striking characteristics of the secreted immune evasion molecules: their conserved structure. Despite high-sequence variability, most immune evasion molecules belong to a small number of structural categories. Another remarkable characteristic is that S. aureus carries most of these virulence factors on mobile genetic elements (MGE) or ex-MGE in its accessory genome. Coevolution of pathogen and host has resulted in immune evasion molecules with a highly host-specific function and prevalence. In this review, we explore how these shared structures and genomic locations relate to function and host specificity. This is discussed in the context of therapeutic options for these immune evasion molecules in infectious as well as in inflammatory diseases.
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Affiliation(s)
- Kirsten J Koymans
- Department of Medical Microbiology, University Medical Center Utrecht, G04-614, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.
| | - Manouk Vrieling
- Department of Medical Microbiology, University Medical Center Utrecht, G04-614, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Ronald D Gorham
- Department of Medical Microbiology, University Medical Center Utrecht, G04-614, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Jos A G van Strijp
- Department of Medical Microbiology, University Medical Center Utrecht, G04-614, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
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