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Tabata A, Nagamune H. Diversity of β-hemolysins produced by the human opportunistic streptococci. Microbiol Immunol 2021; 65:512-529. [PMID: 34591320 DOI: 10.1111/1348-0421.12936] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/17/2021] [Accepted: 08/18/2021] [Indexed: 11/28/2022]
Abstract
The genus Streptococcus infects a broad range of hosts, including humans. Some species, such as S. pyogenes, S. agalactiae, S. pneumoniae, and S. mutans, are recognized as the major human pathogens, and their pathogenicity toward humans has been investigated. However, many of other streptococcal species have been recognized as opportunistic pathogens in humans, and their clinical importance has been underestimated. In our previous study, the Anginosus group streptococci (AGS) and Mitis group streptococci (MGS) showed clear β-hemolysis on blood agar, and the factors responsible for the hemolysis were homologs of two types of β-hemolysins, cholesterol-dependent cytolysin (CDC) and streptolysin S (SLS). In contrast to the regular β-hemolysins produced by streptococci (typical CDCs and SLSs), genetically, structurally, and functionally atypical β-hemolysins have been observed in AGS and MGS. These atypical β-hemolysins are thought to affect and contribute to the pathogenic potential of opportunistic streptococci mainly inhabiting the human oral cavity. In this review, we introduce the diverse characteristics of β-hemolysin produced by opportunistic streptococci, focusing on the species/strains belonging to AGS and MGS, and discuss their pathogenic potential.
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Affiliation(s)
- Atsushi Tabata
- Department of Bioengineering, Division of Bioscience and Bioindustry, Graduate School of Technology, Industrial and Social Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Hideaki Nagamune
- Department of Bioengineering, Division of Bioscience and Bioindustry, Graduate School of Technology, Industrial and Social Sciences, Tokushima University Graduate School, Tokushima, Japan
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Laborde RJ, Ishimura ME, Abreu-Butin L, Nogueira CV, Grubaugh D, Cruz-Leal Y, Luzardo MC, Fernández A, Mesa C, Pazos F, Álvarez C, Alonso ME, Starnbach MN, Higgins DE, Fernández LE, Longo-Maugéri IM, Lanio ME. Sticholysins, pore-forming proteins from a marine anemone can induce maturation of dendritic cells through a TLR4 dependent-pathway. Mol Immunol 2021; 131:144-154. [PMID: 33422341 DOI: 10.1016/j.molimm.2020.12.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 11/30/2020] [Accepted: 12/24/2020] [Indexed: 02/06/2023]
Abstract
Sticholysins (Sts) I and II (StI and StII) are pore-forming proteins (PFPs), purified from the Caribbean Sea anemone Stichodactyla helianthus. StII encapsulated into liposomes induces a robust antigen-specific cytotoxic CD8+ T lymphocytes (CTL) response and in its free form the maturation of bone marrow-derived dendritic cells (BM-DCs). It is probable that the latter is partially supporting in part the immunomodulatory effect on the CTL response induced by StII-containing liposomes. In the present work, we demonstrate that the StII's ability of inducing maturation of BM-DCs is also shared by StI, an isoform of StII. Using heat-denatured Sts we observed a significant reduction in the up-regulation of maturation markers indicating that both PFP's ability to promote maturation of BM-DCs is dependent on their conformational characteristics. StII-mediated DC maturation was abrogated in BM-DCs from toll-like receptor (TLR) 4 and myeloid differentiation primary response gene 88 (MyD88)-knockout mice but not in cells from TLR2-knockout mice. Furthermore, the antigen-specific CTL response induced by StII-containing liposomes was reduced in TLR4-knockout mice. These results indicate that StII, and probably by extension StI, has the ability to induce maturation of DCs through a TLR4/MyD88-dependent pathway, and that this activation contributes to the CTL response generated by StII-containing liposomes.
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Affiliation(s)
- Rady J Laborde
- Laboratory of Toxins and Liposomes, Center for Protein Studies, Faculty of Biology, University of Havana (UH), Lab UH-CIM, Havana, 10400, Cuba.
| | - Mayari E Ishimura
- Discipline of Immunology, Department of Microbiology, Immunology and Parasitology, Federal University of São Paulo (UNIFESP), 04023-062, São Paulo, Brazil.
| | - Lianne Abreu-Butin
- Discipline of Immunology, Department of Microbiology, Immunology and Parasitology, Federal University of São Paulo (UNIFESP), 04023-062, São Paulo, Brazil
| | - Catarina V Nogueira
- Department of Microbiology and Immunobiology of Harvard Medical School, Harvard University, MA, USA.
| | - Daniel Grubaugh
- Department of Microbiology and Immunobiology of Harvard Medical School, Harvard University, MA, USA.
| | - Yoelys Cruz-Leal
- Laboratory of Toxins and Liposomes, Center for Protein Studies, Faculty of Biology, University of Havana (UH), Lab UH-CIM, Havana, 10400, Cuba.
| | - María C Luzardo
- Laboratory of Toxins and Liposomes, Center for Protein Studies, Faculty of Biology, University of Havana (UH), Lab UH-CIM, Havana, 10400, Cuba.
| | - Audry Fernández
- Immunobiology Division, Center of Molecular Immunology (CIM), Havana, 11600, Cuba.
| | - Circe Mesa
- Immunobiology Division, Center of Molecular Immunology (CIM), Havana, 11600, Cuba.
| | - Fabiola Pazos
- Laboratory of Toxins and Liposomes, Center for Protein Studies, Faculty of Biology, University of Havana (UH), Lab UH-CIM, Havana, 10400, Cuba.
| | - Carlos Álvarez
- Laboratory of Toxins and Liposomes, Center for Protein Studies, Faculty of Biology, University of Havana (UH), Lab UH-CIM, Havana, 10400, Cuba.
| | - María E Alonso
- Laboratory of Toxins and Liposomes, Center for Protein Studies, Faculty of Biology, University of Havana (UH), Lab UH-CIM, Havana, 10400, Cuba
| | - Michael N Starnbach
- Department of Microbiology and Immunobiology of Harvard Medical School, Harvard University, MA, USA.
| | - Darren E Higgins
- Department of Microbiology and Immunobiology of Harvard Medical School, Harvard University, MA, USA.
| | - Luis E Fernández
- Immunobiology Division, Center of Molecular Immunology (CIM), Havana, 11600, Cuba.
| | - Ieda M Longo-Maugéri
- Discipline of Immunology, Department of Microbiology, Immunology and Parasitology, Federal University of São Paulo (UNIFESP), 04023-062, São Paulo, Brazil.
| | - María E Lanio
- Laboratory of Toxins and Liposomes, Center for Protein Studies, Faculty of Biology, University of Havana (UH), Lab UH-CIM, Havana, 10400, Cuba.
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Garcia MM, Goicoechea C, Molina-Álvarez M, Pascual D. Toll-like receptor 4: A promising crossroads in the diagnosis and treatment of several pathologies. Eur J Pharmacol 2020; 874:172975. [PMID: 32017939 DOI: 10.1016/j.ejphar.2020.172975] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 12/20/2019] [Accepted: 01/29/2020] [Indexed: 12/26/2022]
Abstract
Toll-like receptor 4 (TLR4) is expressed in a wide variety of cells and is the central component of the mammalian innate immune system. Since its discovery in 1997, TLR4 has been assigned an ever-increasing number of functions that extend from pathogen recognition to tissue damage identification and promotion of the intrinsic "damage repair response" in pain, intestinal, respiratory and vascular disorders. Precisely, the finding of conserved sequence homology among species along with the molecular and functional characterisation of the TLR4 gene enabled researchers to envisage a common operating system in the activation of innate immunity and the initiation of plastic changes at the onset of chronic pain. Malfunctioning in other conditions was conceived in parallel. In this respect, "pivot" proteins and pathway redundancy are not just evolutionary leftovers but essential for normal functioning or cell survival. Indeed, at present, TLR4 single nucleotide polymorphisms (SNP) and their association with certain dysfunctions and diseases are being confirmed in different pools of patients. However, despite its ability to trigger pathogen infection or alternatively tissue injury communications to immune system, TLR4 targeting might not be considered a panacea. This review article represents a compilation of what we know about TLR4 from clinics and basic research on the 20th anniversary of its discovery. Understanding how to fine-tune the interaction between TLR4 and its specific ligands may lead in the next decades to the development of promising new treatments, reducing polypharmacy and probably having an impact on drug use in numerous pathologies.
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Affiliation(s)
- Miguel M Garcia
- Area of Pharmacology, Nutrition and Bromatology, Department of Basic Health Sciences, Universidad Rey Juan Carlos, Avda, Atenas S/n, 28922, Alcorcón, Spain
| | - Carlos Goicoechea
- Area of Pharmacology, Nutrition and Bromatology, Department of Basic Health Sciences, Universidad Rey Juan Carlos, Avda, Atenas S/n, 28922, Alcorcón, Spain
| | - Miguel Molina-Álvarez
- Area of Pharmacology, Nutrition and Bromatology, Department of Basic Health Sciences, Universidad Rey Juan Carlos, Avda, Atenas S/n, 28922, Alcorcón, Spain
| | - David Pascual
- Area of Pharmacology, Nutrition and Bromatology, Department of Basic Health Sciences, Universidad Rey Juan Carlos, Avda, Atenas S/n, 28922, Alcorcón, Spain.
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Lavagna A, Auger JP, Dumesnil A, Roy D, Girardin SE, Gisch N, Segura M, Gottschalk M. Interleukin-1 signaling induced by Streptococcus suis serotype 2 is strain-dependent and contributes to bacterial clearance and inflammation during systemic disease in a mouse model of infection. Vet Res 2019; 50:52. [PMID: 31262357 PMCID: PMC6604435 DOI: 10.1186/s13567-019-0670-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 06/14/2019] [Indexed: 12/12/2022] Open
Abstract
Streptococcus suis serotype 2 is an important porcine pathogen and zoonotic agent causing sudden death, septic shock and meningitis, with exacerbated inflammation being a hallmark of the infection. A rapid, effective and balanced innate immune response against S. suis is critical to control bacterial growth without causing excessive inflammation. Even though interleukin (IL)-1 is one of the most potent and earliest pro-inflammatory mediators produced, its role in the S. suis pathogenesis has not been studied. We demonstrated that a classical virulent European sequence type (ST) 1 strain and the highly virulent ST7 strain induce important levels of IL-1 in systemic organs. Moreover, bone marrow-derived dendritic cells and macrophages contribute to its production, with the ST7 strain inducing higher levels. To better understand the underlying mechanisms involved, different cellular pathways were studied. Independently of the strain, IL-1β production required MyD88 and involved recognition via TLR2 and possibly TLR7 and TLR9. This suggests that the recognized bacterial components are similar and conserved between strains. However, very high levels of the pore-forming toxin suilysin, produced only by the ST7 strain, are required for efficient maturation of pro-IL-1β via activation of different inflammasomes resulting from pore formation and ion efflux. Using IL-1R−/− mice, we demonstrated that IL-1 signaling plays a beneficial role during S. suis systemic infection by modulating the inflammation required to control and clear bacterial burden, thus promoting host survival. Beyond a certain threshold, however, S. suis-induced inflammation cannot be counterbalanced by this signaling, making it difficult to discriminate its role.
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Affiliation(s)
- Agustina Lavagna
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - Jean-Philippe Auger
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - Audrey Dumesnil
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - David Roy
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - Stephen E Girardin
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Nicolas Gisch
- Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Mariela Segura
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - Marcelo Gottschalk
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada.
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Pan Q, Liu Y, Zhu X, Liu H. Chloral hydrate-dependent reduction in the peptidoglycan-induced inflammatory macrophage response is associated with lower expression levels of toll-like receptor 2. Exp Ther Med 2014; 7:1305-1310. [PMID: 24940429 PMCID: PMC3991540 DOI: 10.3892/etm.2014.1587] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 02/21/2014] [Indexed: 12/24/2022] Open
Abstract
The aim of this study was to investigate the effect and mechanism of action of chloral hydrate on the peptidoglycan (PGN)-induced inflammatory macrophage response. The effect of chloral hydrate on the production of tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) by murine peritoneal macrophages with PGN-stimulation was investigated. In addition, RAW264.7 cells transfected with a nuclear factor-κB (NF-κB) luciferase reporter plasmid stimulated by PGN were used to study the effect of chloral hydrate on the levels NF-κB activity. Flow cytometry and western blotting were performed to investigate the expression levels of toll-like receptor 2 (TLR2) in the treated RAW264.7 cells. It was identified that chloral hydrate reduced the levels of IL-6 and TNF-α produced by the peritoneal macrophages stimulated with PGN. The levels of NF-κB activity of the RAW264.7 cells stimulated by PGN decreased following treatment with chloral hydrate, which was associated with a reduction in the expression levels of TLR2 and reduced levels of TLR2 signal transduction. These data demonstrate that chloral hydrate reduced the magnitude of the PGN-induced inflammatory macrophage response associated with lower expression levels of TLR2.
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Affiliation(s)
- Qingjun Pan
- Institute of Nephrology, Affiliated Hospital of Guangdong Medical College, Zhangjiang, Guangdong 524001, P.R. China
| | - Yuan Liu
- Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, SAR 999077, P.R. China
| | - Xuezhi Zhu
- Guangdong Yuehai Feed Group Co. Ltd., Zhangjiang, Guangdong 524001, P.R. China
| | - Huafeng Liu
- Institute of Nephrology, Affiliated Hospital of Guangdong Medical College, Zhangjiang, Guangdong 524001, P.R. China
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Keyel PA, Roth R, Yokoyama WM, Heuser JE, Salter RD. Reduction of streptolysin O (SLO) pore-forming activity enhances inflammasome activation. Toxins (Basel) 2013; 5:1105-18. [PMID: 23744055 PMCID: PMC3717772 DOI: 10.3390/toxins5061105] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 05/29/2013] [Accepted: 06/03/2013] [Indexed: 12/21/2022] Open
Abstract
Pore-forming toxins are utilized by bacterial and mammalian cells to exert pathogenic effects and induce cell lysis. In addition to rapid plasma membrane repair, macrophages respond to pore-forming toxins through activation of the NLRP3 inflammasome, leading to IL-1β secretion and pyroptosis. The structural determinants of pore-forming toxins required for NLRP3 activation remain unknown. Here, we demonstrate using streptolysin O (SLO) that pore-formation controls IL-1β secretion and direct toxicity. An SLO mutant incapable of pore-formation did not promote direct killing, pyroptosis or IL-1β production. This indicated that pore formation is necessary for inflammasome activation. However, a partially active mutant (SLO N402C) that was less toxic to macrophages than wild-type SLO, even at concentrations that directly lysed an equivalent number of red blood cells, enhanced IL-1β production but did not alter pyroptosis. This suggests that direct lysis may attenuate immune responses by preventing macrophages from successfully repairing their plasma membrane and elaborating more robust cytokine production. We suggest that mutagenesis of pore-forming toxins represents a strategy to enhance adjuvant activity.
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Affiliation(s)
- Peter A. Keyel
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15260, USA; E-Mail:
| | - Robyn Roth
- Department of Cell Biology and Physiology, Washington University, St. Louis, MO 63110, USA; E-Mails: (R.R.); (J.E.H.)
| | - Wayne M. Yokoyama
- Howard Hughes Medical Institute and Rheumatology Division, Department of Medicine, Washington University, St. Louis, MO 63110, USA; E-Mail:
| | - John E. Heuser
- Department of Cell Biology and Physiology, Washington University, St. Louis, MO 63110, USA; E-Mails: (R.R.); (J.E.H.)
| | - Russell D. Salter
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15260, USA; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-412-648-9471; Fax: +1-412-383-8096
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Listeria monocytogenes-derived listeriolysin O has pathogen-associated molecular pattern-like properties independent of its hemolytic ability. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2012; 20:77-84. [PMID: 23136118 DOI: 10.1128/cvi.00488-12] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
There is a constant need for improved adjuvants to augment the induction of immune responses against tumor-associated antigens (TAA) during immunotherapy. Previous studies have established that listeriolysin O (LLO), a cholesterol-dependent cytolysin derived from Listeria monocytogenes, exhibits multifaceted effects to boost the stimulation of immune responses to a variety of antigens. However, the direct ability of LLO as an adjuvant and whether it acts as a pathogen-associated molecular pattern (PAMP) have not been demonstrated. In this paper, we show that a detoxified, nonhemolytic form of LLO (dtLLO) is an effective adjuvant in tumor immunotherapy and may activate innate and cellular immune responses by acting as a PAMP. Our investigation of the adjuvant activity demonstrates that dtLLO, either fused to or administered as a mixture with a human papillomavirus type 16 (HPV-16) E7 recombinant protein, can augment antitumor immune responses and facilitate tumor eradication. Further mechanistic studies using bone marrow-derived dendritic cells suggest that dtLLO acts as a PAMP by stimulating production of proinflammatory cytokines and inducing maturation of antigen-presenting cells (APC). We propose that dtLLO is an effective adjuvant for tumor immunotherapy, and likely for other therapeutic settings.
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Wang H, Wu Y, Ojcius DM, Yang XF, Zhang C, Ding S, Lin X, Yan J. Leptospiral hemolysins induce proinflammatory cytokines through Toll-like receptor 2-and 4-mediated JNK and NF-κB signaling pathways. PLoS One 2012; 7:e42266. [PMID: 22870312 PMCID: PMC3411626 DOI: 10.1371/journal.pone.0042266] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 07/02/2012] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Infection with pathogenic Leptospira species causes serious systemic inflammation in patients. Although a few leptospiral proinflammatory molecules have been identified, Leptospira likely encodes other unidentified strong inflammation stimulators. The pathogenic L. interrogans genome encodes numerous putative hemolysin genes. Since hemolysins from other bacteria can cause inflammatory reactions, we hypothesized that leptospiral hemolysins may function as proinflammatory stimulators that contribute to the strong inflammation associated with Leptospira infection. METHODOLOGY/PRINCIPAL FINDINGS We first used cytokine protein microarrays for systematic analysis of serum cytokine profiles in leptospirosis patients and leptospire-infected mice. We found that IL-1β, IL-6 and TNF-α were the main proinflammatory cytokines in the sera of both the patients and the mice. We then analyzed eight putative hemolysins in L. interrogans strain Lai. The results showed that five of them, Sph1, Sph2, Sph3, HlpA and TlyA were secreted and had hemolytic activity. More importantly, these five hemolysins induced the strong production of IL-1β, IL-6 and TNF-α in human and mouse macrophages (although a bit lower in the latter). Furthermore, blockade of TLR2 or TLR4 with either antibodies or inhibitors of the NF-κB or JNK signaling pathways significantly reduced the production of hemolysin-induced IL-1β, IL-6 and TNF-α. Macrophages isolated from TLR2-, TLR4-or double TLR2-and 4-deficient mice also confirmed that the leptospiral hemolysins that induce proinflammatory cytokines are both TLR2-and TLR4-dependent. CONCLUSIONS/SIGNIFICANCE Our findings demonstrate that L. interrogans secretes many hemolysins that function as powerful inducers of proinflammatory cytokines through both TLR2-and TLR4-dependent JNK and NF-κB pathways.
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Affiliation(s)
- Huan Wang
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Yifei Wu
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - David M. Ojcius
- Health Sciences Research Institute and Molecular Cell Biology, University of California, Merced, California, United States of America
| | - X. Frank Yang
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Chenglin Zhang
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Shibiao Ding
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xu’ai Lin
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- * E-mail: (JY); (XL)
| | - Jie Yan
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- * E-mail: (JY); (XL)
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Horowitz A, Stegmann KA, Riley EM. Activation of natural killer cells during microbial infections. Front Immunol 2012; 2:88. [PMID: 22566877 PMCID: PMC3342047 DOI: 10.3389/fimmu.2011.00088] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Accepted: 12/16/2011] [Indexed: 12/24/2022] Open
Abstract
Natural killer (NK) cells are large granular lymphocytes that express a diverse array of germline encoded inhibitory and activating receptors for MHC Class I and Class I-like molecules, classical co-stimulatory ligands, and cytokines. The ability of NK cells to be very rapidly activated by inflammatory cytokines, to secrete effector cytokines, and to kill infected or stressed host cells, suggests that they may be among the very early responders during infection. Recent studies have also identified a small number of pathogen-derived ligands that can bind to NK cell surface receptors and directly induce their activation. Here we review recent studies that have begun to elucidate the various pathways by which viral, bacterial, and parasite pathogens activate NK cells. We also consider two emerging themes of NK cell–pathogen interactions, namely their contribution to adaptive immune responses and their potential to take on regulatory and immunomodulatory functions.
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Affiliation(s)
- Amir Horowitz
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine London, UK
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Novosad BD, Astley RA, Callegan MC. Role of Toll-like receptor (TLR) 2 in experimental Bacillus cereus endophthalmitis. PLoS One 2011; 6:e28619. [PMID: 22163046 PMCID: PMC3232239 DOI: 10.1371/journal.pone.0028619] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Accepted: 11/11/2011] [Indexed: 12/24/2022] Open
Abstract
Bacillus cereus causes a uniquely rapid and blinding intraocular infection, endophthalmitis. B. cereus replicates in the eye, synthesizes numerous toxins, and incites explosive intraocular inflammation. The mechanisms involved in the rapid and explosive intraocular immune response have not been addressed. Because Toll-like receptors (TLRs) are integral to the initial recognition of organisms during infection, we hypothesized that the uniquely explosive immune response observed during B. cereus endophthalmitis is directly influenced by the presence of TLR2, a known gram-positive pathogen recognition receptor. To address this hypothesis, we compared the courses of experimental B. cereus endophthalmitis in wild type C57BL/6J mice to that of age-matched homozygous TLR2(-/-) mice. Output parameters included analysis of bacterial growth, inflammatory cell (PMN) infiltration, cytokine/chemokine kinetics, retinal function testing, and histology, with N≥4 eyes/assay/time point/mouse strain. B. cereus grew at similar rates to10(8) CFU/eye by 12 h, regardless of the mouse strain. Retinal function was preserved to a greater degree in infected TLR2(-/-) eyes compared to that of infected wild type eyes, but infected eyes of both mouse strains lost significant function. Retinal architecture was preserved in infected TLR2(-/-) eyes, with limited retinal and vitreal cellular infiltration compared to that of infected wild type eyes. Ocular myeloperoxidase activities corroborated these results. In general, TNFα, IFNγ, IL6, and KC were detected in greater concentrations in infected wild type eyes than in infected TLR2(-/-) eyes. The absence of TLR2 resulted in decreased intraocular proinflammatory cytokine/chemokine levels and altered recruitment of inflammatory cells into the eye, resulting in less intraocular inflammation and preservation of retinal architecture, and a slightly greater degree of retinal function. These results demonstrate TLR2 is an important component of the initial ocular response to B. cereus endophthalmitis.
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Affiliation(s)
- Billy D. Novosad
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Roger A. Astley
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Michelle C. Callegan
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- Dean A. McGee Eye Institute, Oklahoma City, Oklahoma, United States of America
- * E-mail:
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Tukhvatulin AI, Logunov DY, Shcherbinin DN, Shmarov MM, Naroditsky BS, Gudkov AV, Gintsburg AL. Toll-like receptors and their adapter molecules. BIOCHEMISTRY (MOSCOW) 2011; 75:1098-114. [PMID: 21077829 DOI: 10.1134/s0006297910090038] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Toll-like receptors (TLR) are among key receptors of the innate mammalian immune system. Receptors of this family are able to recognize specific highly conserved molecular regions (patterns) in pathogen structures, thus initiating reactions of both innate and acquired immune response finally resulting in the elimination of the pathogen. In this case every individual TLR type is able to bind a broad spectrum of molecules of microbial origin characterized by different chemical properties and structures. Recent data demonstrate the existence of a multistep mechanism of the TLR recognition of the pathogen in which, in addition to receptors proper, the involvement of different adapter molecules is necessary. However, functions of separate adapter molecules as well as the principles of formation of a multicomponent system of ligand-specific recognition are still not quite understandable. We describe all identified as well as possible (candidate) adapter TLR molecules by giving their brief characteristics, and we also propose generalized possible variants of the TLR ligand-specific recognition with involvement of adapter molecules.
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Affiliation(s)
- A I Tukhvatulin
- Gamaleya Institute of Epidemiology and Microbiology, Russian Academy of Medical Sciences, Moscow, 123098, Russia.
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Chu J, Thomas LM, Watkins SC, Franchi L, Núñez G, Salter RD. Cholesterol-dependent cytolysins induce rapid release of mature IL-1beta from murine macrophages in a NLRP3 inflammasome and cathepsin B-dependent manner. J Leukoc Biol 2009; 86:1227-38. [PMID: 19675207 DOI: 10.1189/jlb.0309164] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
CDC are exotoxins secreted by many Gram-positive bacteria that bind cholesterol and oligomerize to form pores in eukaryotic cell membranes. We demonstrate that CDC TLO induces caspase-1 cleavage and the rapid release of IL-1beta from LPS-primed murine BMDM. IL-1beta secretion depends on functional toxin pore formation, as free cholesterol, which prevents TLO binding to cell membranes, blocks the cytokine release. Secretion of the mature forms of IL-1beta and caspase-1 occurs only at lower TLO doses, whereas at a higher concentration, cells release the biologically inactive proforms. IL-1beta release at a low TLO dose requires potassium efflux, calcium influx, and the activities of calcium-independent PLA(2), caspase-1, and cathepsin B. Additionally, mature IL-1beta release induced by a low TLO dose is dependent on the NLRP3 inflammasome, and pro-IL-1beta release induced by a high TLO dose occurs independently of NLRP3. These results further elucidate a mechanism of CDC-induced IL-1beta release and suggest a novel, immune evasion strategy in which IL-1beta-containing macrophages might release primarily inactive cytokine following exposure to high doses of these toxins.
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Affiliation(s)
- Jessica Chu
- Immunology Graduate Program, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
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13
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Multiple mechanisms contribute to the robust rapid gamma interferon response by CD8+ T cells during Listeria monocytogenes infection. Infect Immun 2009; 77:1492-501. [PMID: 19179413 DOI: 10.1128/iai.01207-08] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A subset of CD8+ T cells can rapidly secrete gamma interferon (IFN-gamma) in an antigen-independent and interleukin-12 (IL-12)- and IL-18-dependent manner within 16 h of infection with the intracellular bacterial pathogen Listeria monocytogenes. This rapid IFN-gamma response is robust enough to be detected directly ex vivo and is not observed following infection with intracellular bacterial pathogens that remain sequestered within host cell vacuoles. We demonstrate here that three distinct pathways can lead to rapid secretion of IFN-gamma by CD8+ T cells during L. monocytogenes infection: (i) a direct cytokine-inducing activity encoded by the cholesterol-dependent cytolysin (CDC) listeriolysin O (LLO) acts within the infected cell, (ii) the pore-forming activity of LLO promotes cytosolic localization of bacterial products that trigger cytosol-specific signaling pathways, and (iii) the sustained presence of high concentrations of bacterial products can exogenously trigger cytokine production. Although it has been suggested that CDC protein toxins may act as Toll-like receptor 4 (TLR4) agonists to trigger proinflammatory cytokine secretion, we show in this report that TLR4 signaling is not required to induce a maximal rapid IFN-gamma response by CD8+ T cells. The results presented here indicate that multiple mechanisms contribute to the induction of rapid IFN-gamma secretion by CD8+ T cells during Listeria infection and that care must be taken when interpreting the results of in vitro assays, since the contribution of each pathway can vary depending on how the assay is performed.
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14
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Volcy K, Dewhurst S. Proteasome inhibitors enhance bacteriophage lambda (lambda) mediated gene transfer in mammalian cells. Virology 2008; 384:77-87. [PMID: 19064273 PMCID: PMC2654414 DOI: 10.1016/j.virol.2008.11.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2008] [Revised: 09/10/2008] [Accepted: 11/11/2008] [Indexed: 11/05/2022]
Abstract
Bacteriophage lambda vectors can transfer their genomes into mammalian cells, resulting in expression of phage-encoded genes. However, this process is inefficient. Experiments were therefore conducted to delineate the rate limiting step(s) involved, using a phage vector that contains a mammalian luciferase reporter gene cassette. The efficiency of phage-mediated gene transfer in mammalian cells was quantitated, in the presence or absence of pharmacologic inhibitors of cell uptake and degradation pathways. Inhibitors of lysosomal proteases and proteasome inhibitors strongly enhanced phage-mediated luciferase expression, suggesting that these pathways contribute to the destruction of intracellular phage particles. In contrast, inhibition of endosome acidification had no effect on phage-mediated gene transfer, presumably because phage lambda is tolerant to extended exposure to low pH. These findings provide insights into the pathways by which phage vectors enter and transduce mammalian cells, and suggest that it may be possible to pharmacologically enhance the efficiency of phage-mediated gene transfer in mammalian cells. Finally, the data also suggest that the proteasome complex may serve as an innate defense mechanism that restricts the infection of mammalian cells by diverse viral agents.
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Affiliation(s)
- Ketna Volcy
- Department of Microbiology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
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15
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Rosado CJ, Kondos S, Bull TE, Kuiper MJ, Law RHP, Buckle AM, Voskoboinik I, Bird PI, Trapani JA, Whisstock JC, Dunstone MA. The MACPF/CDC family of pore-forming toxins. Cell Microbiol 2008; 10:1765-74. [PMID: 18564372 PMCID: PMC2654483 DOI: 10.1111/j.1462-5822.2008.01191.x] [Citation(s) in RCA: 211] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pore-forming toxins (PFTs) are commonly associated with bacterial pathogenesis. In eukaryotes, however, PFTs operate in the immune system or are deployed for attacking prey (e.g. venoms). This review focuses upon two families of globular protein PFTs: the cholesterol-dependent cytolysins (CDCs) and the membrane attack complex/perforin superfamily (MACPF). CDCs are produced by Gram-positive bacteria and lyse or permeabilize host cells or intracellular organelles during infection. In eukaryotes, MACPF proteins have both lytic and non-lytic roles and function in immunity, invasion and development. The structure and molecular mechanism of several CDCs are relatively well characterized. Pore formation involves oligomerization and assembly of soluble monomers into a ring-shaped pre-pore which undergoes conformational change to insert into membranes, forming a large amphipathic transmembrane β-barrel. In contrast, the structure and mechanism of MACPF proteins has remained obscure. Recent crystallographic studies now reveal that although MACPF and CDCs are extremely divergent at the sequence level, they share a common fold. Together with biochemical studies, these structural data suggest that lytic MACPF proteins use a CDC-like mechanism of membrane disruption, and will help understand the roles these proteins play in immunity and development.
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Affiliation(s)
- Carlos J Rosado
- Department of Biochemistry, Monash University, Clayton, Victoria 3800, Australia
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16
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Critical involvement of pneumolysin in production of interleukin-1alpha and caspase-1-dependent cytokines in infection with Streptococcus pneumoniae in vitro: a novel function of pneumolysin in caspase-1 activation. Infect Immun 2008; 76:1547-57. [PMID: 18195026 DOI: 10.1128/iai.01269-07] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Pneumolysin is a pore-forming cytolysin known as a major virulence determinant of Streptococcus pneumoniae. This protein toxin has also been shown to activate the Toll-like receptor 4 (TLR4) signaling pathway. In this study, a mutant S. pneumoniae strain deficient in pneumolysin (Deltaply) and a recombinant pneumolysin protein (rPLY) were constructed. Upon infection of macrophages in vitro, the ability to induce the production of interleukin-1alpha (IL-1alpha), IL-1beta, and IL-18 was severely impaired in the Deltaply mutant, whereas there was no marked difference in the induction of tumor necrosis factor alpha (TNF-alpha) and IL-12p40 between the wild type and the Deltaply mutant of S. pneumoniae. When macrophages were stimulated with rPLY, the production of IL-1alpha, IL-1beta, and IL-18 was strongly induced in a TLR4-dependent manner, whereas lipopolysaccharide, a canonical TLR4 agonist, hardly induced these cytokines. In contrast, lipopolysaccharide was more potent than rPLY in inducing the production of TNF-alpha, IL-6, and IL-12p40, the cytokines requiring no caspase activation. Activation of caspase-1 was observed in macrophages stimulated with rPLY but not in those stimulated with lipopolysaccharide, and the level of activation was higher in macrophages infected with wild-type S. pneumoniae than in those infected with the Deltaply mutant. These results clearly indicate that pneumolysin plays a key role in the host response to S. pneumoniae, particularly in the induction of caspase-1-dependent cytokines.
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Newman KC, Riley EM. Whatever turns you on: accessory-cell-dependent activation of NK cells by pathogens. Nat Rev Immunol 2007; 7:279-91. [PMID: 17380157 DOI: 10.1038/nri2057] [Citation(s) in RCA: 185] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Natural killer (NK) cells have a crucial role in combating infections and cancers and their surface receptors can directly recognize and respond to damaged, transformed or non-self cells. Whereas some virus-infected cells are recognized by this same route, NK-cell responses to many pathogens are triggered by a different mechanism. Activation of NK cells by these pathogens requires the presence of accessory cells such as monocytes, macrophages and dendritic cells. Recent studies have identified numerous pathogen-recognition receptors that enable accessory cells to recognize different pathogens and subsequently transmit signals--both soluble and contact-dependent--to NK cells, which respond by upregulating their cytotoxic potential and the production of inflammatory cytokines.
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Affiliation(s)
- Kirsty C Newman
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
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18
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Gaudreault E, Fiola S, Olivier M, Gosselin J. Epstein-Barr virus induces MCP-1 secretion by human monocytes via TLR2. J Virol 2007; 81:8016-24. [PMID: 17522215 PMCID: PMC1951286 DOI: 10.1128/jvi.00403-07] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Epstein-Barr virus (EBV) is a gammaherpesvirus infecting the majority of the human adult population in the world. TLR2, a member of the Toll-like receptor (TLR) family, has been implicated in the immune responses to different viruses including members of the herpesvirus family, such as human cytomegalovirus, herpes simplex virus type 1, and varicella-zoster virus. In this report, we demonstrate that infectious and UV-inactivated EBV virions lead to the activation of NF-kappaB through TLR2 using HEK293 cells cotransfected with TLR2-expressing vector along with NF-kappaB-Luc reporter plasmid. NF-kappaB activation in HEK293-TLR2 cells (HEK293 cells transfected with TLR2) by EBV was not enhanced by the presence of CD14. The effect of EBV was abrogated by pretreating HEK293-TLR2 cells with blocking anti-TLR2 antibodies or by preincubating viral particles with neutralizing anti-EBV antibodies 72A1. In addition, EBV infection of primary human monocytes induced the release of MCP-1 (monocyte chemotactic protein 1), and the use of small interfering RNA targeting TLR2 significantly reduced such a chemokine response to EBV. Taken together, these results indicate that TLR2 may be an important pattern recognition receptor in the immune response directed against EBV infection.
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Affiliation(s)
- Eric Gaudreault
- Viral Immunology Laboratory, CHUL Research Center (CHUQ), 2705 boul. Laurier, Room T 1-49, Quebec, QC, Canada G1V 4G2
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Hara H, Kawamura I, Nomura T, Tominaga T, Tsuchiya K, Mitsuyama M. Cytolysin-dependent escape of the bacterium from the phagosome is required but not sufficient for induction of the Th1 immune response against Listeria monocytogenes infection: distinct role of Listeriolysin O determined by cytolysin gene replacement. Infect Immun 2007; 75:3791-801. [PMID: 17517863 PMCID: PMC1951982 DOI: 10.1128/iai.01779-06] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Listeria monocytogenes evades the antimicrobial mechanisms of macrophages by escaping from the phagosome into the cytosolic space via a unique cytolysin that targets the phagosomal membrane, listeriolysin O (LLO), encoded by hly. Gamma interferon (IFN-gamma), which is known to play a pivotal role in the induction of Th1-dependent protective immunity in mice, appears to be produced, depending on the bacterial virulence factor. To determine whether the LLO molecule (the major virulence factor of L. monocytogenes) is indispensable or the escape of bacteria from the phagosome is sufficient to induce IFN-gamma production, we first constructed an hly-deleted mutant of L. monocytogenes and then established isogenic L. monocytogenes mutants expressing LLO or ivanolysin O (ILO), encoded by ilo from Listeria ivanovii. LLO-expressing L. monocytogenes was highly capable of inducing IFN-gamma production and Listeria-specific protective immunity, while the hly-deleted mutant was not. In contrast, the level of IFN-gamma induced by ILO-expressing L. monocytogenes was significantly lower both in vitro and in vivo, despite the ability of this strain to escape the phagosome and the intracellular multiplication at a level equivalent to that of LLO-expressing L. monocytogenes. Only a negligible level of protective immunity was induced in mice against challenge with LLO- and ILO-expressing L. monocytogenes. These results clearly show that escape of the bacterium from the phagosome is a prerequisite but is not sufficient for the IFN-gamma-dependent Th1 response against L. monocytogenes, and some distinct molecular nature of LLO is indispensable for the final induction of IFN-gamma that is essentially required to generate a Th1-dependent immune response.
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Affiliation(s)
- Hideki Hara
- Department of Microbiology, Kyoto University Graduate School of Medicine, Yoshida-konoecho, Sakyo-ku, Kyoto 606-8501, Japan
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