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Krangvichian P, Techawiwattanaboon T, Palaga T, Ritprajak P, Kueanjinda P, Kaewraemruaen C, Patarakul K. Impaired functions of human monocyte-derived dendritic cells and induction of regulatory T cells by pathogenic Leptospira. PLoS Negl Trop Dis 2023; 17:e0011781. [PMID: 37983293 PMCID: PMC10695387 DOI: 10.1371/journal.pntd.0011781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 12/04/2023] [Accepted: 11/08/2023] [Indexed: 11/22/2023] Open
Abstract
Leptospirosis is a global zoonosis caused by pathogenic Leptospira. The disease outcome is influenced by the interplay between innate and adaptive immune responses. Dendritic cells (DCs) play a crucial role in shaping the adaptive immune response. A recent study revealed that pathogenic Leptospira limited the activation of human monocyte-derived dendritic cells (MoDCs) compared to non-pathogenic Leptospira, but their impact on T-cell responses has not been investigated. Our study is the first to explore how viable pathogenic and non-pathogenic Leptospira affect the interaction between human MoDCs and T cells. We found that MoDCs infected with pathogenic leptospires (L. interrogans serovar Pomona and a clinical isolate, MoDCs-P) exhibited lower levels of CD80 and CD83 expression, suggesting partially impaired MoDC maturation, induced regulatory T cells (Tregs) while failing to induce CD4+ T cell proliferation, compared to MoDCs infected with non-pathogenic leptospires (L. biflexa serovar Patoc and L. meyeri serovar Ranarum, MoDCs-NP). In contrast, non-pathogenic leptospires enhanced MoDC maturation and induced higher T cell proliferation including IFN-γ-producing CD4+ T cells, indicative of a Th1-type response. Furthermore, pathogenic leptospires induced higher MoDC apoptosis through a cysteine aspartic acid-specific protease-3 (caspase-3)-dependent pathway and upregulated expression of the prostaglandin-endoperoxide synthase 2 (PTGS2) gene. Notably, prostaglandin E2 (PGE2), a product of the PTGS2 pathway, was found at higher levels in the sera of patients with acute leptospirosis and in the supernatant of MoDCs-P, possibly contributing to Treg induction, compared to those of healthy donors and MoDCs-NP, respectively. In conclusion, this study reveals a novel immunosuppressive strategy employed by pathogenic Leptospira to evade host immunity by partially impairing MoDC maturation and inducing Tregs. These findings deepen our understanding of leptospirosis pathogenesis in humans and may provide a novel strategy to modulate DCs for the prevention and treatment of the disease.
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Affiliation(s)
- Pratomporn Krangvichian
- Medical Microbiology, Interdisciplinary Program, Graduate School, Chulalongkorn University, Bangkok, Thailand
| | - Teerasit Techawiwattanaboon
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Bangkok, Thailand
- Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Bangkok, Thailand
| | - Tanapat Palaga
- Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Bangkok, Thailand
- Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Patcharee Ritprajak
- Research Unit in Integrative Immuno-Microbial Biochemistry and Bioresponsive Nanomaterials, Department of Microbiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - Patipark Kueanjinda
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Bangkok, Thailand
| | - Chamraj Kaewraemruaen
- Department of Science and Bioinnovation, Faculty of Liberal Arts and Science, Kasetsart University, Kamphaeng Saen Campus, Nakhon Pathom, Thailand
| | - Kanitha Patarakul
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Bangkok, Thailand
- Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Bangkok, Thailand
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2
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Pereira JM, Xu S, Leong JM, Sousa S. The Yin and Yang of Pneumolysin During Pneumococcal Infection. Front Immunol 2022; 13:878244. [PMID: 35529870 PMCID: PMC9074694 DOI: 10.3389/fimmu.2022.878244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 03/23/2022] [Indexed: 12/15/2022] Open
Abstract
Pneumolysin (PLY) is a pore-forming toxin produced by the human pathobiont Streptococcus pneumoniae, the major cause of pneumonia worldwide. PLY, a key pneumococcal virulence factor, can form transmembrane pores in host cells, disrupting plasma membrane integrity and deregulating cellular homeostasis. At lytic concentrations, PLY causes cell death. At sub-lytic concentrations, PLY triggers host cell survival pathways that cooperate to reseal the damaged plasma membrane and restore cell homeostasis. While PLY is generally considered a pivotal factor promoting S. pneumoniae colonization and survival, it is also a powerful trigger of the innate and adaptive host immune response against bacterial infection. The dichotomy of PLY as both a key bacterial virulence factor and a trigger for host immune modulation allows the toxin to display both "Yin" and "Yang" properties during infection, promoting disease by membrane perforation and activating inflammatory pathways, while also mitigating damage by triggering host cell repair and initiating anti-inflammatory responses. Due to its cytolytic activity and diverse immunomodulatory properties, PLY is integral to every stage of S. pneumoniae pathogenesis and may tip the balance towards either the pathogen or the host depending on the context of infection.
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Affiliation(s)
- Joana M. Pereira
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Molecular and Cellular (MC) Biology PhD Program, ICBAS - Instituto de Ciência Biomédicas Abel Salazar, University of Porto, Porto, Portugal
| | - Shuying Xu
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, United States
- Graduate Program in Immunology, Tufts Graduate School of Biomedical Sciences, Boston, MA, United States
| | - John M. Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, United States
| | - Sandra Sousa
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
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3
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Selvaraj C, Vierra M, Dinesh DC, Abhirami R, Singh SK. Structural insights of macromolecules involved in bacteria-induced apoptosis in the pathogenesis of human diseases. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2021; 126:1-38. [PMID: 34090612 DOI: 10.1016/bs.apcsb.2021.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Numbers of pathogenic bacteria can induce apoptosis in human host cells and modulate the cellular pathways responsible for inducing or inhibiting apoptosis. These pathogens are significantly recognized by host proteins and provoke the multitude of several signaling pathways and alter the cellular apoptotic stimuli. This process leads the bacterial entry into the mammalian cells and evokes a variety of responses like phagocytosis, release of mitochondrial cytochrome c, secretion of bacterial effectors, release of both apoptotic and inflammatory cytokines, and the triggering of apoptosis. Several mechanisms are involved in bacteria-induced apoptosis including, initiation of the endogenous death machinery, pore-forming proteins, and secretion of superantigens. Either small molecules or proteins may act as a binding partner responsible for forming the protein complexes and regulate enzymatic activity via protein-protein interactions. The bacteria induce apoptosis, attack the human cell and gain control over various types of cells and tissue. Since these processes are intricate in the defense mechanisms of host organisms against pathogenic bacteria and play an important function in host-pathogen interactions. In this chapter, we focus on the various bacterial-induced apoptosis mechanisms in host cells and discuss the important proteins and bacterial effectors that trigger the host cell apoptosis. The structural characterization of bacterial effector proteins and their interaction with human host cells are also considered.
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Affiliation(s)
- Chandrabose Selvaraj
- Computer Aided Drug Design and Molecular Modeling Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi, Tamil Nadu, India.
| | - Marisol Vierra
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI, United States
| | | | - Rajaram Abhirami
- Computer Aided Drug Design and Molecular Modeling Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi, Tamil Nadu, India
| | - Sanjeev Kumar Singh
- Computer Aided Drug Design and Molecular Modeling Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi, Tamil Nadu, India.
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4
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Hosomi K, Shibata N, Shimoyama A, Uto T, Nagatake T, Tojima Y, Nishino T, Takeyama H, Fukase K, Kiyono H, Kunisawa J. Lymphoid Tissue-Resident Alcaligenes Establish an Intracellular Symbiotic Environment by Creating a Unique Energy Shift in Dendritic Cells. Front Microbiol 2020; 11:561005. [PMID: 33101234 PMCID: PMC7545135 DOI: 10.3389/fmicb.2020.561005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 09/07/2020] [Indexed: 12/03/2022] Open
Abstract
Lymphoid-tissue–resident commensal bacteria (LRCs), including Alcaligenes faecalis, are present in intestinal lymphoid tissue including the Peyer’s patches (PPs) of mammals and modulate the host immune system. Although LRCs can colonize within dendritic cells (DCs), the mechanisms through which LRCs persist in DCs and the symbiotic relationships between LRCs and DCs remain to be investigated. Here, we show an intracellular symbiotic system in which the LRC Alcaligenes creates a unique energy shift in DCs. Whereas DCs showed low mitochondrial respiration when they were co-cultured with Escherichia coli, DCs carrying A. faecalis maintained increased mitochondrial respiration. Furthermore, E. coli induced apoptosis of DCs but A. faecalis did not. Regarding an underlying mechanism, A. faecalis—unlike E. coli—did not induce intracellular nitric oxide (NO) production in DCs due to the low activity of its lipopolysaccharide (LPS). Therefore, A. faecalis, an example of LRCs, may persist within intestinal lymphoid tissue because they elicit little NO production in DCs. In addition, the symbiotic DCs exhibit characteristic physiologic changes, including a low rate of apoptosis and increased mitochondrial respiration.
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Affiliation(s)
- Koji Hosomi
- Laboratory of Vaccine Materials, Center for Vaccine and Adjuvant Research, Ibaraki, Japan.,Laboratory of Gut Environmental System, National Institutes of Biomedical Innovation, Health, and Nutrition (NIBIOHN), Ibaraki, Japan
| | - Naoko Shibata
- Laboratory of Vaccine Materials, Center for Vaccine and Adjuvant Research, Ibaraki, Japan.,Laboratory of Gut Environmental System, National Institutes of Biomedical Innovation, Health, and Nutrition (NIBIOHN), Ibaraki, Japan.,International Research and Development Center for Mucosal Vaccines, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan.,Research Organization for Nano and Life Innovation, Waseda University, Tokyo, Japan
| | | | - Tomoya Uto
- Graduate School of Science, Osaka University, Toyonaka, Japan
| | - Takahiro Nagatake
- Laboratory of Vaccine Materials, Center for Vaccine and Adjuvant Research, Ibaraki, Japan.,Laboratory of Gut Environmental System, National Institutes of Biomedical Innovation, Health, and Nutrition (NIBIOHN), Ibaraki, Japan
| | - Yoko Tojima
- Laboratory of Vaccine Materials, Center for Vaccine and Adjuvant Research, Ibaraki, Japan.,Laboratory of Gut Environmental System, National Institutes of Biomedical Innovation, Health, and Nutrition (NIBIOHN), Ibaraki, Japan
| | - Tomomi Nishino
- Laboratory of Vaccine Materials, Center for Vaccine and Adjuvant Research, Ibaraki, Japan.,Laboratory of Gut Environmental System, National Institutes of Biomedical Innovation, Health, and Nutrition (NIBIOHN), Ibaraki, Japan
| | - Haruko Takeyama
- Research Organization for Nano and Life Innovation, Waseda University, Tokyo, Japan.,Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan
| | - Koichi Fukase
- Graduate School of Science, Osaka University, Toyonaka, Japan
| | - Hiroshi Kiyono
- International Research and Development Center for Mucosal Vaccines, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan.,IMSUT Distinguished Professor Unit, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan.,Graduate School of Medicine, Chiba University, Chuo City, Japan.,Department of Medicine, School of Medicine and Chiba University - UC San Diego Center for Mucosal Immunology, Allergy, and Vaccine, University of California, San Diego, San Diego, CA, United States
| | - Jun Kunisawa
- Laboratory of Vaccine Materials, Center for Vaccine and Adjuvant Research, Ibaraki, Japan.,Laboratory of Gut Environmental System, National Institutes of Biomedical Innovation, Health, and Nutrition (NIBIOHN), Ibaraki, Japan.,International Research and Development Center for Mucosal Vaccines, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan.,Research Organization for Nano and Life Innovation, Waseda University, Tokyo, Japan.,IMSUT Distinguished Professor Unit, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan.,Graduate School of Medicine, Chiba University, Chuo City, Japan.,Department of Medicine, School of Medicine and Chiba University - UC San Diego Center for Mucosal Immunology, Allergy, and Vaccine, University of California, San Diego, San Diego, CA, United States.,Graduate School of Medicine, Osaka University, Suita, Japan.,Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan.,Graduate School of Density, Osaka University, Suita, Japan.,Graduate School of Medicine, Kobe University, Kobe, Japan
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5
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Visweshwaran SP, Maritzen T. A simple 3D cellular chemotaxis assay and analysis workflow suitable for a wide range of migrating cells. MethodsX 2019; 6:2807-2821. [PMID: 31871915 PMCID: PMC6909357 DOI: 10.1016/j.mex.2019.11.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 11/04/2019] [Indexed: 12/30/2022] Open
Abstract
Cellular migration plays a crucial role within multicellular organisms enabling organ development, wound healing and efficient immune responses, but also metastasis. Therefore, it is crucial to dissect the underlying mechanisms. Directed migration and invasion are most efficient in response to chemotactic signals. To study cell migration and chemotactic responses, current experimental setups use either simplified 2D, tissue-mimetic 3D (e.g. collagen matrices) or in vivo environments. While the in vivo experiments are closest to the real physiological situation, they require animal experiments and are thus ill-suited for screening purposes. 3D matrices, on the other hand, can mimic in vivo conditions in many respects thus serving as instructive settings for the initial dissection of cell migration and chemotaxis. However, performing 3D chemotaxis assays has its limitations due to the delicate nature of most available setups and the tedious and time-consuming manual quantification process. Here, we present •A method for the easy construction of a chemotaxis chamber suitable for the analysis of large cell numbers.•A procedure to quantify their migration automatically with minimal input required by the experimenter.•Both successfully validated by analyzing the 3D chemotaxis of highly migratory primary dendritic cells and the invasive MDA-MB-231 cancer cells.
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Affiliation(s)
- Sai P Visweshwaran
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Tanja Maritzen
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Straße 10, 13125 Berlin, Germany
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6
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Domain 4 of pneumolysin from Streptococcus pneumoniae is a multifunctional domain contributing TLR4 activating and hemolytic activity. Biochem Biophys Res Commun 2019; 517:596-602. [PMID: 31395343 DOI: 10.1016/j.bbrc.2019.07.063] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 07/18/2019] [Indexed: 11/21/2022]
Abstract
The pneumolysin (Ply) protein of Streptococcus pneumoniae is composed of four domains and possesses several different but related activities. In this study, recombinant Ply and two truncated forms, Ply domain 1-3 and Ply domain 4 (rPly4), were expressed and characterized regarding their participation in apoptosis, the stimulation of cytokine production, hemolytic activity and virulence. rPly4 activated murine bone marrow-derived dendritic cells in a Toll-like receptor (TLR) 4-dependent manner. The rPly4 alone was able to produce hemolytic activity at high concertation and penetrate the lipid bilayer. We further demonstrated that domain 4 of Ply involved in the virulence of the bacteria in mouse model. In the absence of apoptotic activity, the virulence level caused by rPly4 was similar to that of full length Ply. Our data suggested that domain 4 of Ply alone with TLR4 agonist and hemolytic activity may play roles in virulence of Streptococcus pneumoniae.
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7
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Viseshakul N, Dechkhajorn W, Benjathummarak S, Nuamtanong S, Maneerat Y. Excretory-secretory product of third-stage Gnathostoma spinigerum larvae induces apoptosis in human peripheral blood mononuclear cells. Parasitol Res 2017; 116:2783-2794. [PMID: 28836111 DOI: 10.1007/s00436-017-5589-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 08/09/2017] [Indexed: 11/24/2022]
Abstract
Human gnathostomiasis caused by third-stage Gnathostoma spinigerum larvae (G. spinigerum L3) is an important zoonotic disease in tropical areas of the world. The excretory-secretory products (ES) that are excreted by infective larva play a significant role in host immune evasion and tissue destruction. To investigate the poorly understood mechanisms of G. spinigerum L3 pathogenesis, we focused on the potential effect of ES on inducing apoptosis in human immune cells by using human peripheral blood mononuclear cells (PBMCs) as a model. Early and late apoptosis of PBMCs were assessed following the exposure of these cells to G. spinigerum L3 ES (0.1, 0.5, and 1.0 μg/ml) for 6-48 h. The apoptotic cells were identified by flow cytometric staining of PBMC with FITC-annexin V and propidium iodide. The expression of regulatory genes related to apoptosis mechanisms in ES-treated PBMCs was investigated using a Human Apoptosis RT2 Profiler™ PCR Array. The results showed significant levels of early phase apoptosis at 18 h and of late phase apoptosis at 24 h. We speculate that this apoptosis in PBMCs occurs via the extrinsic pathway. Apoptosis in the ES-induced PBMCs was observed as quickly as 90 min after exposure, and the highest effect was observed at 18-24 h. Furthermore, ES can trigger apoptosis lasting for 48 h. Our findings expand the understanding of one of the mechanisms involved, immune-evasive strategy mechanism used by G. spinigerum larvae during human gnathostomiasis.
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Affiliation(s)
- Nareerat Viseshakul
- Parasitology Unit, Department of Pathology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Wilanee Dechkhajorn
- Department of Tropical Pathology, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand
| | - Surachet Benjathummarak
- Center of Excellence for Antibody Research, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand
| | - Supaporn Nuamtanong
- Department of Helminthology, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand
| | - Yaowapa Maneerat
- Department of Tropical Pathology, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand.
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8
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Kubicka-Sierszen A, Grzegorczyk JŁ. The influence of infectious factors on dendritic cell apoptosis. Arch Med Sci 2015; 11:1044-51. [PMID: 26528349 PMCID: PMC4624750 DOI: 10.5114/aoms.2015.54860] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 06/04/2013] [Accepted: 10/02/2013] [Indexed: 12/23/2022] Open
Abstract
Pathogens can have a negative influence on dendritic cells (DCs), causing their apoptosis, which prevents active presentation of foreign antigens. It results in a state of immunosuppression which makes the body susceptible to secondary infections. Infected immature DCs have lower expression of co-stimulatory and adhesion molecules, reduced ability to secrete cytokines and an inhibited maturation process and are incapable of effective antigen presentation and activation of T-lymphocytes. In some cases, the ability of DCs to undergo rapid apoptosis is important for the body defense, which is probably because of DCs' ability to cross-present and cooperate with other cells. Apoptotic bodies released from the infected DCs are phagocytosed by other DCs, which then stimulate the effector cells and present antigens more efficiently than infected cells. The aim of this article is to review how the DCs respond to viral and bacterial factors and which biochemical mechanisms are responsible for their apoptosis.
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Affiliation(s)
- Agata Kubicka-Sierszen
- Department of Microbiology and Laboratory Medical Immunology, Faculty of Medicine, Medical University of Lodz, Lodz, Poland
| | - Janina Ł Grzegorczyk
- Department of Microbiology and Laboratory Medical Immunology, Faculty of Medicine, Medical University of Lodz, Lodz, Poland
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9
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Vashishta M, Khan N, Mehto S, Sehgal D, Natarajan K. Pneumococal Surface Protein A (PspA) Regulates Programmed Death Ligand 1 Expression on Dendritic Cells in a Toll-Like Receptor 2 and Calcium Dependent Manner. PLoS One 2015. [PMID: 26214513 PMCID: PMC4516265 DOI: 10.1371/journal.pone.0133601] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Pneumonia leads to high mortality in children under the age of five years worldwide, resulting in close to 20 percent of all deaths in this age group. Therefore, investigations into host-pathogen interactions during Streptococcus pneumoniae infection are key in devising strategies towards the development of better vaccines and drugs. To that end, in this study we investigated the role of S. pneumoniae and its surface antigen Pneumococcal surface protein A (PspA) in modulating the expression of co-stimulatory molecule Programmed Death Ligand 1 (PD-L1) expression on dendritic cells (DCs) and the subsequent effects of increased PD-L1 on key defence responses. Our data indicate that stimulation of DCs with PspA increases the surface expression of PD-L1 in a time and dose dependent manner. Characterization of mechanisms involved in PspA induced expression of PD-L1 indicate the involvement of Toll-Like Receptor 2 (TLR2) and calcium homeostasis. While calcium release from intracellular stores positively regulated PD-L1 expression, calcium influx from external milieu negatively regulated PD-L1 expression. Increase in PD-L1 expression, when costimulated with PspA and through TLR2 was higher than when stimulated with PspA or through TLR2. Further, knockdown of TLR2 and the intermediates in the TLR signaling machinery pointed towards the involvement of a MyD88 dependent pathway in PspA induced PD-L1 expression. Incubation of DCs with S. pneumoniae resulted in the up-regulation of PD-L1 expression, while infection with a strain lacking surface PspA failed to do so. Our data also suggests the role of PspA in ROS generation. These results suggest a novel and specific role for PspA in modulating immune responses against S. pneumoniae by regulating PD-L1 expression.
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Affiliation(s)
- Mohit Vashishta
- Infectious Disease Immunology Laboratory, Dr. B. R. Ambedkar Centre for Biomedical Research, University of Delhi, Delhi, India
- * E-mail: (MV); (KN); (DS)
| | - Naeem Khan
- Molecular Immunology Laboratory, National Institute of Immunology, New Delhi, India
| | - Subhash Mehto
- Infectious Disease Immunology Laboratory, Dr. B. R. Ambedkar Centre for Biomedical Research, University of Delhi, Delhi, India
| | - Devinder Sehgal
- Molecular Immunology Laboratory, National Institute of Immunology, New Delhi, India
- * E-mail: (MV); (KN); (DS)
| | - Krishnamurthy Natarajan
- Infectious Disease Immunology Laboratory, Dr. B. R. Ambedkar Centre for Biomedical Research, University of Delhi, Delhi, India
- * E-mail: (MV); (KN); (DS)
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10
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Rai R, Das B, Choudhary N, Talukdar A, Rao DN. MAP of F1 and V antigens from Yersinia pestis astride innate and adaptive immune response. Microb Pathog 2015; 87:13-20. [PMID: 26188288 DOI: 10.1016/j.micpath.2015.07.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 07/05/2015] [Accepted: 07/13/2015] [Indexed: 01/31/2023]
Abstract
Yersinia pestis, a causative agent of plague, has a plethora of armors to fight against major components of innate immunity and survive within host cells. Dendritic cells and macrophages are important antigen presenting cells for effective immune response. This report is focused on the changes in DC activation and TLR2 and TLR4 expression on macrophages induced by MAP of F1 and V antigens of Y. pestis. F1 and V MAPs bear potential synthetic T and B cell epitopes from F1 and V protein respectively. We evaluated these parameters in DC's isolated from spleen and lamina propria and macrophages isolated from peritoneal lavage of mice after intranasal immunization. F1 MAP and V MAP significantly increased the expression of CD80 and CD86 on CD11c(+) dendritic cells isolated from spleen and lamina propria as well as intracellular IL-12 levels. Similarly, in macrophages derived from peritoneal cavity, the above formulation enhanced TLR2 and TLR4 expression. Again after in vitro stimulation with F1 and V MAP these macrophages produced significantly high IL12 and TNFα. The study clearly indicates involvement of DC and macrophages for efficient antigen presentation to immune cells. From this study we conclude that F1MAP and VMAP ameliorate innate immune mechanism. These two synthetic constructs exert their effect via TLR2 and TLR4, leading to the production of proinflammatory cytokines by macrophages and are able to increase DC activation, that could be helpful in generation of adaptive immunity as well as is important strong immune response.
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Affiliation(s)
- Reeta Rai
- Dept of Biochemistry, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Baijnath Das
- Dept of Biochemistry, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Nageshwar Choudhary
- Dept of Biochemistry, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Ayantika Talukdar
- Dept of Biochemistry, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
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11
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Streptococcus pneumoniae secretes hydrogen peroxide leading to DNA damage and apoptosis in lung cells. Proc Natl Acad Sci U S A 2015; 112:E3421-30. [PMID: 26080406 DOI: 10.1073/pnas.1424144112] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Streptococcus pneumoniae is a leading cause of pneumonia and one of the most common causes of death globally. The impact of S. pneumoniae on host molecular processes that lead to detrimental pulmonary consequences is not fully understood. Here, we show that S. pneumoniae induces toxic DNA double-strand breaks (DSBs) in human alveolar epithelial cells, as indicated by ataxia telangiectasia mutated kinase (ATM)-dependent phosphorylation of histone H2AX and colocalization with p53-binding protein (53BP1). Furthermore, results show that DNA damage occurs in a bacterial contact-independent fashion and that Streptococcus pyruvate oxidase (SpxB), which enables synthesis of H2O2, plays a critical role in inducing DSBs. The extent of DNA damage correlates with the extent of apoptosis, and DNA damage precedes apoptosis, which is consistent with the time required for execution of apoptosis. Furthermore, addition of catalase, which neutralizes H2O2, greatly suppresses S. pneumoniae-induced DNA damage and apoptosis. Importantly, S. pneumoniae induces DSBs in the lungs of animals with acute pneumonia, and H2O2 production by S. pneumoniae in vivo contributes to its genotoxicity and virulence. One of the major DSBs repair pathways is nonhomologous end joining for which Ku70/80 is essential for repair. We find that deficiency of Ku80 causes an increase in the levels of DSBs and apoptosis, underscoring the importance of DNA repair in preventing S. pneumoniae-induced genotoxicity. Taken together, this study shows that S. pneumoniae-induced damage to the host cell genome exacerbates its toxicity and pathogenesis, making DNA repair a potentially important susceptibility factor in people who suffer from pneumonia.
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12
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Cole J, Aberdein J, Jubrail J, Dockrell DH. The role of macrophages in the innate immune response to Streptococcus pneumoniae and Staphylococcus aureus: mechanisms and contrasts. Adv Microb Physiol 2014; 65:125-202. [PMID: 25476766 DOI: 10.1016/bs.ampbs.2014.08.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Macrophages are critical mediators of innate immune responses against bacteria. The Gram-positive bacteria Streptococcus pneumoniae and Staphylococcus aureus express a range of virulence factors, which challenge macrophages' immune competence. We review how macrophages respond to this challenge. Macrophages employ a range of strategies to phagocytose and kill each pathogen. When the macrophages capacity to clear bacteria is overwhelmed macrophages play important roles in orchestrating the inflammatory response through pattern recognition receptor-mediated responses. Macrophages also ensure the inflammatory response is tightly constrained, to avoid tissue damage, and play an important role in downregulating the inflammatory response once initial bacterial replication is controlled.
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Affiliation(s)
- Joby Cole
- Department of Infection and Immunity, University of Sheffield Medical School and Sheffield Teaching Hospitals, Sheffield, United Kingdom
| | - Jody Aberdein
- Department of Infection and Immunity, University of Sheffield Medical School and Sheffield Teaching Hospitals, Sheffield, United Kingdom
| | - Jamil Jubrail
- Department of Infection and Immunity, University of Sheffield Medical School and Sheffield Teaching Hospitals, Sheffield, United Kingdom
| | - David H Dockrell
- Department of Infection and Immunity, University of Sheffield Medical School and Sheffield Teaching Hospitals, Sheffield, United Kingdom.
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Dhariwala MO, Anderson DM. Bacterial programming of host responses: coordination between type I interferon and cell death. Front Microbiol 2014; 5:545. [PMID: 25389418 PMCID: PMC4211556 DOI: 10.3389/fmicb.2014.00545] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 09/30/2014] [Indexed: 01/24/2023] Open
Abstract
During mammalian infection, bacteria induce cell death from an extracellular or intracellular niche that can protect or hurt the host. Data is accumulating that associate type I interferon (IFN) signaling activated by intracellular bacteria with programmed death of immune effector cells and enhanced virulence. Multiple pathways leading to IFN-dependent host cell death have been described, and in some cases it is becoming clear how these mechanisms contribute to virulence. Yet common mechanisms of IFN-enhanced bacterial pathogenesis are not obvious and no specific interferon stimulated genes have yet been identified that cause sensitivity to pathogen-induced cell death. In this review, we will summarize some bacterial infections caused by facultative intracellular pathogens and what is known about how type I IFN signaling may promote the replication of extracellular bacteria rather than stimulate protection. Each of these pathogens can survive phagocytosis but their intracellular life cycles are very different, they express distinct virulence factors and trigger different pathways of immune activation and crosstalk. These differences likely lead to widely varying amounts of type I IFN expression and a different inflammatory environment, but these may not be important to the pathologic effects on the host. Instead, each pathogen induces programmed cell death of key immune cells that have been sensitized by the activation of the type I IFN response. We will discuss how IFN-dependent host cell death may increase host susceptibility and try to understand common pathways of pathogenesis that lead to IFN-enhanced bacterial virulence.
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Affiliation(s)
- Miqdad O Dhariwala
- Department of Veterinary Pathobiology, University of Missouri Columbia, MO, USA
| | - Deborah M Anderson
- Department of Veterinary Pathobiology, University of Missouri Columbia, MO, USA
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Towhid ST, Nega M, Schmidt EM, Schmid E, Albrecht T, Münzer P, Borst O, Götz F, Lang F. Stimulation of platelet apoptosis by peptidoglycan from Staphylococcus aureus 113. Apoptosis 2013; 17:998-1008. [PMID: 22752708 DOI: 10.1007/s10495-012-0718-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Peptidoglycan (PGN), a component of bacterial cell wall and belonging to "Microbe-Associated Molecular Patterns" (MAMP) triggers host reactions contributing to the pathophysiology of infectious disease. Host cell responses to PGN exposure include apoptosis. Bacterial infections may result in activation of blood platelets and thrombocytopenia. The present study explored, whether HPLC-purified fractions of PGNs from Staphylococcus aureus 113 triggers apoptosis of platelets. To this end platelets were exposed to PGN fractions and annexin-V binding determined to depict cell membrane scrambling, DiOC6 fluorescence to estimate depolarization of mitochondrial potential, Fluo-3AM staining for intracellular Ca(2+) activity ([Ca(2+)](i)) and immunofluorescence to quantify protein abundance of active caspase-3. As a result, a 30 min exposure to monomeric fraction (mPGN) (≥50 ng/ml) was followed by annexin-V binding, paralleled by increase of [Ca(2+)](i), mitochondrial depolarization, caspase-3 activation and integrin α(IIb)β(3) upregulation. The annexin-V binding was significantly blunted by anti-TLR-2 antibodies, in absence of extracellular Ca(2+), and by pancaspase inhibitor zVAD-FMK (1 μM). In conclusion, PGN triggers apoptosis of platelets in activation-dependent manner, characterized by mitochondrial depolarization, caspase-3 activation and cell membrane scrambling.
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Affiliation(s)
- Syeda T Towhid
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany
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Colino J, Duke L, Snapper CM. Noncovalent association of protein and capsular polysaccharide on bacteria-sized latex beads as a model for polysaccharide-specific humoral immunity to intact gram-positive extracellular bacteria. THE JOURNAL OF IMMUNOLOGY 2013; 191:3254-63. [PMID: 23926322 DOI: 10.4049/jimmunol.1300722] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Intact Streptococcus pneumoniae expressing type 14 capsular polysaccharide (PPS14) and type III S. agalactiae containing a PPS14 core capsule identical to PPS14 exhibit noncovalent associations of PPS14 and bacterial protein, in contrast to soluble covalent conjugates of these respective Ags. Both bacteria and conjugates induce murine PPS14-specific IgG responses dependent on CD4⁺ T cells. Further, secondary immunization with conjugate and S. agalactiae, although not S. pneumoniae, results in a boosted response. However, in contrast to conjugate, PPS14-specific IgG responses to bacteria lack affinity maturation use the 44.1-idiotype and are dependent on marginal zone B cells. To better understand the mechanism underlying this dichotomy, we developed a minimal model of intact bacteria in which PPS14 and pneumococcal surface protein A (PspA) were stably attached to 1 μm (bacteria-sized) latex beads, but not directly linked to each other, in contrast to PPS14-PspA conjugate. Beads coated simultaneously with PPS14+[PspA], similar to conjugate, induced in mice boosted PPS14-specific IgG secondary responses, dependent on T cells and ICOS-dependent costimulation, and in which priming could be achieved with PspA alone. In contrast to conjugate, but similar to intact bacteria, the primary PPS14-specific IgG response to beads coated simultaneously with PPS14+[PspA] peaked rapidly, with the secondary response highly enriched for the 44.1-idiotype and lacking affinity maturation. These results demonstrate that noncovalent association in a particle, of polysaccharide and protein, recapitulates essential immunologic characteristics of intact bacteria that are distinct from soluble covalent conjugates of these respective Ags.
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Affiliation(s)
- Jesus Colino
- Department of Pathology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
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16
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Novel synthetic (poly)glycerolphosphate-based antistaphylococcal conjugate vaccine. Infect Immun 2013; 81:2554-61. [PMID: 23649092 DOI: 10.1128/iai.00271-13] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Staphylococcal infections are a major source of global morbidity and mortality. Currently there exists no antistaphylococcal vaccine in clinical use. Previous animal studies suggested a possible role for purified lipoteichoic acid as a vaccine target for eliciting protective IgG to several Gram-positive pathogens. Since the highly conserved (poly)glycerolphosphate backbone of lipoteichoic acid is a major antigenic target of the humoral immune system during staphylococcal infections, we developed a synthetic method for producing glycerol phosphoramidites to create a covalent 10-mer of (poly)glycerolphosphate for potential use in a conjugate vaccine. We initially demonstrated that intact Staphylococcus aureus elicits murine CD4(+) T cell-dependent (poly)glycerolphosphate-specific IgM and IgG responses in vivo. Naive mice immunized with a covalent conjugate of (poly)glycerolphosphate and tetanus toxoid in alum plus CpG-oligodeoxynucleotides produced high secondary titers of serum (poly)glycerolphosphate-specific IgG. Sera from immunized mice enhanced opsonophagocytic killing of live Staphylococcus aureus in vitro. Mice actively immunized with the (poly)glycerolphosphate conjugate vaccine showed rapid clearance of staphylococcal bacteremia in vivo relative to mice similarly immunized with an irrelevant conjugate vaccine. In contrast to purified, natural lipoteichoic acid, the (poly)glycerolphosphate conjugate vaccine itself exhibited no detectable inflammatory activity. These data suggest that a synthetic (poly)glycerolphosphate-based conjugate vaccine will contribute to active protection against extracellular Gram-positive pathogens expressing this highly conserved backbone structure in their membrane-associated lipoteichoic acid.
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Abed M, Towhid ST, Pakladok T, Alesutan I, Götz F, Gulbins E, Lang F. Effect of bacterial peptidoglycan on erythrocyte death and adhesion to endothelial cells. Int J Med Microbiol 2013; 303:182-9. [PMID: 23537625 DOI: 10.1016/j.ijmm.2013.01.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 01/16/2013] [Accepted: 01/27/2013] [Indexed: 11/20/2022] Open
Abstract
Peptidoglycans, bacterial wall components, have previously been shown to trigger eryptosis, the suicidal erythrocyte death, characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine exposure at the cell surface. Phosphatidylserine exposing erythrocytes adhere to the vascular wall at least partially by interaction of erythrocytic phosphatidylserine with endothelial CXC chemokine ligand 16 (CXCL16). The present study explored whether peptidoglycan exposure fosters the adhesion of erythrocytes to human umbilical vein endothelial cells (HUVEC). To this end, HUVEC were treated for 48 h with peptidoglycan (10 μg/ml) and CXCL16 abundance determined by confocal microscopy and FACS analysis. Moreover, human erythrocytes were exposed for 48 h to peptidoglycan (10 μg/ml) and phosphatidylserine exposure estimated from binding of fluorescent annexin-V, cell volume from forward scatter in FACS analysis and erythrocyte adhesion to human umbilical vein endothelial cells (HUVEC) from trapping of labeled erythrocytes in a flow chamber. As a result, bacterial peptidoglycan exposure was followed by increased CXCL16 expression in HUVEC as well as erythrocyte shrinkage, phosphatidylserine exposure and adhesion to HUVEC under flow conditions at arterial shear rates. The adhesion was significantly attenuated but not abrogated in the presence of either, erythrocyte phosphatidylserine-coating annexin-V (5 μl/ml) or CXCL16 neutralizing antibody directed against endothelial CXCL16 (4 μg/ml). In conclusion, exposure to peptidoglycan increases endothelial CXCL16 expression and leads to eryptosis followed by phosphatidylserine- and CXCL16-mediated adhesion of eryptotic erythrocytes to vascular endothelial cells.
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Affiliation(s)
- Majed Abed
- Department of Physiology, University of Tuebingen, Tuebingen, Germany
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18
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Cao J, Gong Y, Dong S, Zhang L, Lai X, Zhang X, Yin Y. Pneumococcal ClpP modulates the maturation and activation of human dendritic cells: implications for pneumococcal infections. J Leukoc Biol 2013; 93:737-49. [PMID: 23381472 DOI: 10.1189/jlb.0812428] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
DCs are essential for host immune response to pathogens. Pneumococcal diseases still remain to be a major global-health issue, and HSP100/ClpP is a ubiquitously present virulence determinant for Streptococcus pneumoniae. Here, we show that ClpP expression facilitates the uptake and phagocytosis of pneumococci by human DCs, and it could increase apoptosis of DCs infected with pneumococci. Furthermore, pneumococcal ClpP is required for optimal production of inflammatory cytokines and chemokines and an efficient activation of adaptive immune response in DCs. Complementary, purified rClpP protein recognizes TLR4 and functionally activates human DCs by augmenting the expression of surface molecules and the production of inflammatory cytokines and chemokines dependent on MAPKs and NF-κB signaling pathways. Besides, ClpP-treated DCs induce T cell proliferation and contribute to Th1 immune response. This study describes a novel role of ClpP in the interaction of DCs with pneumococci that could provide new insight for the progression of pneumococcal diseases and has important implications for designing pneumococcal protein vaccines.
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Affiliation(s)
- Ju Cao
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
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Abstract
Dengue viruses and other members of the Flaviviridae family are emerging human pathogens. Dengue is transmitted to humans by Aedes aegypti female mosquitoes. Following infection through the bite, cells of the hematopoietic lineage, like dendritic cells, are the first targets of dengue virus infection. Dendritic cells (DCs) are key antigen presenting cells, sensing pathogens, processing and presenting the antigens to T lymphocytes, and triggering an adaptive immune response. Infection of DCs by dengue virus may induce apoptosis, impairing their ability to present antigens to T cells, and thereby contributing to dengue pathogenesis. This review focuses on general mechanisms by which dengue virus triggers apoptosis, and possible influence of DC-apoptosis on dengue disease severity.
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Miller CM, Boulter NR, Fuller SJ, Zakrzewski AM, Lees MP, Saunders BM, Wiley JS, Smith NC. The role of the P2X₇ receptor in infectious diseases. PLoS Pathog 2011; 7:e1002212. [PMID: 22102807 PMCID: PMC3213081 DOI: 10.1371/journal.ppat.1002212] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
ATP is an extracellular signal for the immune system, particularly during an inflammatory response. It is sensed by the P2X7 receptor, the expression of which is upregulated by pro-inflammatory cytokines. Activation of the P2X7 receptor opens a cation-specific channel that alters the ionic environment of the cell, activating several pathways, including (i) the inflammasome, leading to production of IL-1β and IL-18; (ii) the stress-activated protein kinase pathway, resulting in apoptosis; (iii) the mitogen-activated protein kinase pathway, leading to generation of reactive oxygen and nitrogen intermediates; and (iv) phospholipase D, stimulating phagosome-lysosome fusion. The P2X7 receptor can initiate host mechanisms to remove pathogens, most particularly those that parasitise macrophages. At the same time, the P2X7 receptor may be subverted by pathogens to modulate host responses. Moreover, recent genetic studies have demonstrated significant associations between susceptibility or resistance to parasites and bacteria, and loss-of-function or gain-of-function polymorphisms in the P2X7 receptor, underscoring its importance in infectious disease.
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Affiliation(s)
- Catherine M. Miller
- Institute for the Biotechnology of Infectious Diseases, University of Technology, Sydney, Broadway, New South Wales, Australia
| | - Nicola R. Boulter
- Institute for the Biotechnology of Infectious Diseases, University of Technology, Sydney, Broadway, New South Wales, Australia
| | - Stephen J. Fuller
- Nepean Clinical School, Nepean Hospital, The University of Sydney, Penrith, New South Wales, Australia
| | - Alana M. Zakrzewski
- Institute for the Biotechnology of Infectious Diseases, University of Technology, Sydney, Broadway, New South Wales, Australia
| | - Michael P. Lees
- Institute for the Biotechnology of Infectious Diseases, University of Technology, Sydney, Broadway, New South Wales, Australia
| | - Bernadette M. Saunders
- Centenary Institute of Cancer Medicine & Cell Biology, The University of Sydney, Camperdown, New South Wales, Australia
| | - James S. Wiley
- Florey Neuroscience Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Nicholas C. Smith
- Queensland Tropical Health Alliance, Faculty of Medicine, Health and Molecular Sciences, James Cook University, Smithfield, Cairns, Queensland, Australia
- * E-mail:
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Abstract
Bacterial meningitis is a medical emergency requiring immediate diagnosis and immediate treatment. Streptococcus pneumoniae and Neisseria meningitidis are the most common and most aggressive pathogens of meningitis. Emerging antibiotic resistance is an upcoming challenge. Clinical and experimental studies have established a more detailed understanding of the mechanisms resulting in brain damage, sequelae and neuropsychological deficits. We summarize the current pathophysiological concept of acute bacterial meningitis and present current treatment strategies.
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Affiliation(s)
- Olaf Hoffman
- Department of Neurology, Charité - Universitaetsmedizin Berlin, Berlin, Germany
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Norcross EW, Sanders ME, Moore QC, Marquart ME. Pathogenesis of A Clinical Ocular Strain of Streptococcus pneumoniae and the Interaction of Pneumolysin with Corneal Cells. ACTA ACUST UNITED AC 2011; 2:108. [PMID: 22229113 DOI: 10.4172/2155-9597.1000108] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Streptococcus pneumoniae is an important cause of bacterial keratitis, an infectious disease of the cornea. This study aimed to determine the importance of pneumolysin (PLY), a pneumococcal virulence factor, in keratitis using a clinical keratitis isolate (K1263) and its isogenic mutant deficient in PLY (K1263ΔPLY) and determine the effect of these strains on primary rabbit corneal epithelial (RCE) cells. Each strain was injected into the corneal stromas of rabbits, clinical examinations were performed, and the recovered bacterial loads were determined. Bacterial extracts were exposed to RCE cells, and morphology and viability were assessed. The mutant strain deficient in PLY, K1263ΔPLY, caused significantly lower ocular disease scores than the parent strain (K1263), although a higher bacterial load was recovered from corneas infected with the mutant strain. Histological examination showed increased inflammatory cells in the anterior chamber and increased edema in eyes infected with the parent strain. RCE cells exposed to the parent strain had significantly decreased cell viability and showed increased evidence of cellular damage. This study confirms that in a strain that can cause clinical keratitis, PLY is a significant cause of the damage associated with pneumococcal keratitis. It also shows for the first time that the results from an in vitro model using RCE cells correlates with in vivo results thereby establishing a less invasive way to study the mechanisms of pneumococcal keratitis.
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Affiliation(s)
- Erin W Norcross
- Department of Microbiology, University of Mississippi Medical Center, Jackson, MS 39216
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Reiss A, Braun JS, Jäger K, Freyer D, Laube G, Bührer C, Felderhoff-Müser U, Stadelmann C, Nizet V, Weber JR. Bacterial pore-forming cytolysins induce neuronal damage in a rat model of neonatal meningitis. J Infect Dis 2010; 203:393-400. [PMID: 21186256 DOI: 10.1093/infdis/jiq047] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Group B Streptococcus (GBS) and Streptococcus pneumoniae (SP) are leading causes of bacterial meningitis in neonates and children. Each pathogen produces a pore-forming cytolytic toxin, β-hemolysin/cytolysin (β-h/c) by GBS and pneumolysin by SP. The aim of this study was to understand the role of these pore-forming cytotoxins, in particular of the GBS β-h/c, as potential neurotoxins in experimental neonatal meningitis. METHODS Meningitis was induced in 7- and 11-day-old rats by intracisternal injection of wild type (WT) GBS or SP and compared with isogenic β-h/c- or pneumolysin-deficient mutants, or a double mutant of SP deficient in pneumolysin and hydrogen peroxide production. RESULTS GBS β-h/c and SP pneumolysin contributed to neuronal damage, worsened clinical outcome and weight loss, but had no influence on the early kinetics of leukocyte influx and bacterial growth in the cerebrospinal fluid. In vitro, β-h/c-induced neuronal apoptosis occurred independently of caspase-activation and was not preventable by the broad spectrum caspase-inhibitor z-VAD-fmk. CONCLUSIONS These data suggest that both cytolytic toxins, the GBS β-h/c and SP pneumolysin, contribute to neuronal damage in meningitis and extend the concept of a key role for bacterial pore-forming cytolysins in the pathogenesis and sequelae of neonatal meningitis.
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Affiliation(s)
- Anja Reiss
- Department of Neonatology, Charité Universitätsmedizin Berlin, Berlin, Germany
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Littmann M, Albiger B, Frentzen A, Normark S, Henriques-Normark B, Plant L. Streptococcus pneumoniae evades human dendritic cell surveillance by pneumolysin expression. EMBO Mol Med 2010; 1:211-22. [PMID: 20049723 PMCID: PMC3378134 DOI: 10.1002/emmm.200900025] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Dendritic cells (DCs) protect the respiratory epithelium via induction of innate immune responses and priming of naïve T cells during the initiation of adaptive immunity. Streptococcus pneumoniae, a commonly carried asymptomatic member of the human nasopharyngeal microflora, can cause invasive and inflammatory diseases and the cholesterol-dependent cytotoxin pneumolysin is a major pneumococcal virulence factor implicated in compounding tissue damage and mediating inflammatory responses. While most studies examining the impact of pneumolysin have been based on murine models, we have focused this study on human DC responses. We show that expression of haemolytic pneumolysin inhibits human DC maturation, induction of proinflammatory cytokines and activation of the inflammasome. Furthermore, intracellular production of pneumolysin induces caspase-dependent apoptosis in infected DCs. Similarly, clinical isolates with non-haemolytic pneumolysin were more proinflammatory and caused less apoptosis compared to clonally related strains with active pneumolysin. This study describes a novel role of pneumolysin in the evasion of human DC surveillance that could have a profound clinical impact upon inflammatory disease progression and highlights the need to study human responses to human-specific pathogens.
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Affiliation(s)
- Marie Littmann
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Nobels väg 16, Stockholm SE-171 77, Sweden
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25
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Cortés G, Wessels MR. Inhibition of dendritic cell maturation by group A Streptococcus. J Infect Dis 2009; 200:1152-61. [PMID: 19712038 DOI: 10.1086/605696] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Exposure to group A Streptococcus (GAS) has been shown to induce maturation of dendritic cells (DC). METHODS To identify bacterial determinants that modulate DC activation in response to GAS infection, we analyzed the induction of maturation in human monocyte-derived DC following exposure to GAS clinical isolates. RESULTS Unexpectedly, only 6 of 24 GAS strains tested induced surface expression of major histocompatibility complex class II and costimulatory molecules CD80 and CD83 to levels consistent with DC maturation. Rather, the majority of the strains did not promote DC maturation, and many triggered DC apoptosis. GAS strains that failed to induce DC maturation were those that produced abundant hyaluronic acid (HA) capsular polysaccharide and/or large amounts of the cytotoxin streptolysin O (SLO). By use of isogenic mutants deficient in HA and/or SLO, we determined that GAS inhibits DC maturation through 2 distinct mechanisms: (1) inhibition of bacterial binding and/or phagocytosis by the HA capsule and (2) SLO-mediated induction of DC apoptosis by intracellular GAS. CONCLUSIONS These results demonstrate that GAS virulence factors modulate maturation and survival of human DC, effects that are likely to have a critical impact on activation of innate and adaptive immune responses to this important human pathogen.
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Affiliation(s)
- Guadalupe Cortés
- Division of Infectious Diseases, Children's Hospital Boston, Boston, Massachusetts 02115, USA
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Noske N, Kämmerer U, Rohde M, Hammerschmidt S. Pneumococcal Interaction with Human Dendritic Cells: Phagocytosis, Survival, and Induced Adaptive Immune Response Are Manipulated by PavA. THE JOURNAL OF IMMUNOLOGY 2009; 183:1952-63. [DOI: 10.4049/jimmunol.0804383] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Rathinam VA, Hoag KA, Mansfield LS. Dendritic cells from C57BL/6 mice undergo activation and induce Th1-effector cell responses against Campylobacter jejuni. Microbes Infect 2008; 10:1316-24. [PMID: 18725315 PMCID: PMC4122427 DOI: 10.1016/j.micinf.2008.07.030] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Revised: 06/10/2008] [Accepted: 07/29/2008] [Indexed: 01/22/2023]
Abstract
Food-borne Campylobacter jejuni (Cj) is an important cause of enteritis. We showed that C57BL/6 and congenic interleukin (IL)-10(-/-) mice serve as models of Cj colonization and enteritis, respectively. Thus, C57BL/6 mice are resistant to Cj induced disease. Because dendritic cells (DCs) are central to regulating adaptive immune responses, we investigated the interaction of Cj with murine bone marrow-derived DCs (BM-DCs) to assess bacterial killing, DC activation, and the ability of Cj-infected BM-DCs to stimulate Campylobacter-specific T cell responses in vitro. BM-DCs challenged with Cj efficiently internalized and killed Cj 11168 and significantly upregulated surface MHC-II, CD40, CD80 and CD86 demonstrating a mature phenotype. Infected BM-DCs secreted significant amounts of tumor necrosis factor-alpha (TNF-alpha), IL-6 and IL-12p70. Formalin-killed Cj also induced maturation of BM-DCs with similar cytokine production but at a significantly lower magnitude than live bacteria. Maximal activation of murine BM-DCs required internalization of Cj; attachment alone was not sufficient to elicit significant responses. Also, various strains of Cj elicited different magnitudes of cytokine production from BM-DCs. Finally, in a coculture system, Cj-infected BM-DCs induced high level interferon-gamma (INF-gamma) production from CD4+T cells indicating Th1 polarization. Thus, DCs from resistant C57BL/6 mice initiate T cell responses against Cj.
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Affiliation(s)
- Vijay A.K. Rathinam
- Comparative Enteric Diseases Laboratory, Michigan State University, East Lansing, MI 48824, USA
- Comparative Medicine and Integrative Biology Program, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA
| | - Kathleen A. Hoag
- Department of Food Science and Human Nutrition and Biomedical Laboratory Diagnostics Program, Michigan State University, East Lansing, MI 48824, USA
| | - Linda S. Mansfield
- Comparative Enteric Diseases Laboratory, Michigan State University, East Lansing, MI 48824, USA
- Comparative Medicine and Integrative Biology Program, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA
- Department of Microbiology and Molecular Genetics, National Food Safety and Toxicology Center, Michigan State University, East Lansing, MI 48824, USA
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MacDonald KL, Speert DP. Differential modulation of innate immune cell functions by theBurkholderia cepaciacomplex:Burkholderia cenocepaciabut notBurkholderia multivoransdisrupts maturation and induces necrosis in human dendritic cells. Cell Microbiol 2008; 10:2138-49. [DOI: 10.1111/j.1462-5822.2008.01197.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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29
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Vasilevsky S, Colino J, Puliaev R, Canaday DH, Snapper CM. Macrophages pulsed with Streptococcus pneumoniae elicit a T cell-dependent antibody response upon transfer into naive mice. THE JOURNAL OF IMMUNOLOGY 2008; 181:1787-97. [PMID: 18641316 DOI: 10.4049/jimmunol.181.3.1787] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Macrophages are less effective than DC at priming naive CD4(+) T cells, suggesting that DC are unique in initiating T cell-dependent Ab responses. We compared the ability of DC and macrophages, pulsed in vitro with Streptococcus pneumoniae, to elicit protein- and polysaccharide-specific Ig isotype production upon adoptive transfer into naive mice. S. pneumoniae-activated DC secreted more proinflammatory and anti-inflammatory cytokines, expressed higher levels of surface MHC class II and CD40, and presented S. pneumoniae or recombinant pneumococcal surface protein A (PspA) to a PspA-specific T hybridoma more efficiently than macrophages. However, upon adoptive transfer into naive mice, S. pneumoniae-pulsed macrophages elicited an IgM or IgG anti-PspA and anti-polysaccharide response comparable in serum titers and IgG isotype distribution to that induced by DC. The IgG anti-PspA response, in contrast to the IgG anti-polysaccharide, to S. pneumoniae-pulsed macrophages was T cell-dependent. S. pneumoniae-pulsed macrophages that were paraformaldehyde-fixed before transfer or lacking expression of MHC class II or CD40 were highly defective in eliciting an anti-PspA response, although the anti-polysaccharide response was largely unaffected. To our knowledge, these data are the first to indicate that macrophages can play an active role in the induction of a T cell-dependent humoral immune response in a naive host.
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Affiliation(s)
- Sam Vasilevsky
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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Preston JA, Dockrell DH. Virulence factors in pneumococcal respiratory pathogenesis. Future Microbiol 2008; 3:205-21. [PMID: 18366340 DOI: 10.2217/17460913.3.2.205] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Streptococcus pneumoniae (the pneumococcus) is a major global cause of human disease. Since the publication of the entire sequence of TIGR4 in 2001, our understanding of this human pathogen has increased significantly. Genetic studies, and the use of mutant strains have refined our understanding of the pathogenic mechanisms of classic pneumococcal virulence factors, including the polysaccharide capsule, pneumolysin and surface-expressed proteins. Genetic screens are identifying novel virulence factors. Characterization of pili and bacteriocins, as well as genes associated with competence, metabolism and resistance to oxidative stress has provided new insights into the genetic diversity of the pneumococcus. Further appreciation of the molecular basis of pneumococcal pathogenesis will lead to more effective strategies for the prevention and management of pneumococcal disease.
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Affiliation(s)
- Julie A Preston
- Section of Infection, Inflammation & Immunity, L-Floor, University of Sheffield School of Medicine & Biomedical Sciences, Royal Hallamshire Hospital, Glossop Road, Sheffield S10 2JF, UK.
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Cytolethal distending toxin induces caspase-dependent and -independent cell death in MOLT-4 cells. Infect Immun 2008; 76:4783-91. [PMID: 18644882 DOI: 10.1128/iai.01612-07] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cytolethal distending toxin (CDT) induces apoptosis using the caspase-dependent classical pathway in the majority of human leukemic T cells (MOLT-4). However, we found the process to cell death is only partially inhibited by pretreatment of the cells with a general caspase inhibitor, z-VAD-fmk. Flow cytometric analysis using annexin V and propidium iodide showed that a 48-h CDT treatment decreased the living cell population by 35% even in the presence of z-VAD-fmk. z-VAD-fmk completely inhibited caspase activity in 24 h CDT-intoxicated cells. Further, CDT with z-VAD-fmk treatment clearly increased the cell population that had a low level of intracellular reactive oxygen. This is a characteristic opposite to that of caspase-dependent apoptosis. Overexpression of bcl2 almost completely inhibited cell death using CDT treatment in the presence of z-VAD-fmk. The data suggest there are at least two different pathways used in CDT-induced cell death: conventional caspase-dependent (early) apoptotic cell death and caspase-independent (late) death. Both occur via the mitochondrial membrane disruption pathway.
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Sheets SM, Robles-Price AG, McKenzie RME, Casiano CA, Fletcher HM. Gingipain-dependent interactions with the host are important for survival of Porphyromonas gingivalis. FRONTIERS IN BIOSCIENCE : A JOURNAL AND VIRTUAL LIBRARY 2008; 13:3215-38. [PMID: 18508429 PMCID: PMC3403687 DOI: 10.2741/2922] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Porphyromonas gingivalis, a major periodontal pathogen, must acquire nutrients from host derived substrates, overcome oxidative stress and subvert the immune system. These activities can be coordinated via the gingipains which represent the most significant virulence factor produced by this organism. In the context of our contribution to this field, we will review the current understanding of gingipain biogenesis, glycosylation, and regulation, as well as discuss their role in oxidative stress resistance and apoptosis. We can postulate a model, in which gingipains may be part of the mechanism for P. gingivalis virulence.
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Affiliation(s)
- Shaun M. Sheets
- Department of Biochemistry and Microbiology, School of Medicine, Loma Linda University, Loma Linda, California
| | - Antonette G. Robles-Price
- Department of Biochemistry and Microbiology, School of Medicine, Loma Linda University, Loma Linda, California
| | - Rachelle M. E. McKenzie
- Department of Biochemistry and Microbiology, School of Medicine, Loma Linda University, Loma Linda, California
| | - Carlos A. Casiano
- Department of Biochemistry and Microbiology, School of Medicine, Loma Linda University, Loma Linda, California
- The Center for Health Disparities and Molecular Medicine, Loma Linda University, Loma Linda, California
| | - Hansel M. Fletcher
- Department of Biochemistry and Microbiology, School of Medicine, Loma Linda University, Loma Linda, California
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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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Herrada AA, Contreras FJ, Tobar JA, Pacheco R, Kalergis AM. Immune complex-induced enhancement of bacterial antigen presentation requires Fcgamma receptor III expression on dendritic cells. Proc Natl Acad Sci U S A 2007; 104:13402-7. [PMID: 17679697 PMCID: PMC1948949 DOI: 10.1073/pnas.0700999104] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Dendritic cells (DCs) are capable of initiating adaptive immune responses against infectious agents by presenting pathogen-derived antigens on MHC molecules to naïve T cells. Because of their key role in priming adaptive immunity, it is expected that interfering with DC function would be advantageous to the pathogen. We have previously shown that Salmonella enterica serovar Typhimurium (ST), is able to survive inside DCs and interfere with their function by avoiding activation of bacteria-specific T cells. In contrast, when ST is targeted to Fcgamma receptors on the DC surface, bacteria are degraded and their antigens presented to T cells. However, the specific Fcgamma receptor responsible of restoring presentation of antigens remains unknown. Here, we show that IgG-coated ST was targeted to lysosomes and degraded and its antigens presented on MHC molecules only when the low-affinity activating FcgammaRIII was expressed on DCs. FcgammaRIII-mediated enhancement of Ag presentation led to a robust activation of T cells specific for bacteria-expressed antigens. Laser confocal and electron microscopy analyses revealed that IgG-coated ST was rerouted to the lysosomal pathway through an FcgammaRIII-dependent mechanism. PI-3K activity was required for this process, because specific inhibitors promoted the survival of IgG-coated ST inside DCs and prevented DCs from activating bacteria-specific T cells. Our data suggest that the DC capacity to efficiently activate T cells upon capturing IgG-coated virulent bacteria is mediated by FcgammaRIII and requires PI-3K activity.
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Affiliation(s)
- Andrés A. Herrada
- *Millennium Nucleus on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas and
| | - Francisco J. Contreras
- *Millennium Nucleus on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas and
| | - Jaime A. Tobar
- *Millennium Nucleus on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas and
| | - Rodrigo Pacheco
- *Millennium Nucleus on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas and
| | - Alexis M. Kalergis
- *Millennium Nucleus on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas and
- Departamento de Reumatología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago E-8331010, Chile
- To whom correspondence should be addressed at:
Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda #340, Santiago E-8331010, Chile. E-mail:
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Braun JS, Hoffmann O, Schickhaus M, Freyer D, Dagand E, Bermpohl D, Mitchell TJ, Bechmann I, Weber JR. Pneumolysin causes neuronal cell death through mitochondrial damage. Infect Immun 2007; 75:4245-54. [PMID: 17562768 PMCID: PMC1951198 DOI: 10.1128/iai.00031-07] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial toxins such as pneumolysin are key mediators of cytotoxicity in infections. Pneumolysin is a pore-forming toxin released by Streptococcus pneumoniae, the major cause of bacterial meningitis. We found that pneumolysin is the pneumococcal factor that accounts for the cell death pathways induced by live bacteria in primary neurons. The pore-forming activity of pneumolysin is essential for the induction of mitochondrial damage and apoptosis. Pneumolysin colocalized with mitochondrial membranes, altered the mitochondrial membrane potential, and caused the release of apoptosis-inducing factor and cell death. Pneumolysin induced neuronal apoptosis without activating caspase-1, -3, or -8. Wild-type pneumococci also induced apoptosis without activation of caspase-3, whereas pneumolysin-negative pneumococci activated caspase-3 through the release of bacterial hydrogen peroxide. Pneumolysin caused upregulation of X-chromosome-linked inhibitor of apoptosis protein and inhibited staurosporine-induced caspase activation, suggesting the presence of actively suppressive mechanisms on caspases. In conclusion, our results indicate additional functions of pneumolysin as a mitochondrial toxin and as a determinant of caspase-independent apoptosis. Considering this, blocking of pneumolysin may be a promising cytoprotective strategy in pneumococcal meningitis and other infections.
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Affiliation(s)
- Johann S Braun
- Department of Neurology, Charité Universitaetsmedizin Berlin, Berlin, Germany.
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Hoffmann O, Braun JS, Becker D, Halle A, Freyer D, Dagand E, Lehnardt S, Weber JR. TLR2 Mediates Neuroinflammation and Neuronal Damage. THE JOURNAL OF IMMUNOLOGY 2007; 178:6476-81. [PMID: 17475877 DOI: 10.4049/jimmunol.178.10.6476] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Innate immunity relies on pattern recognition receptors to detect the presence of infectious pathogens. In the case of Gram-positive bacteria, binding of bacterial lipopeptides to TLR2 is currently regarded as an important mechanism. In the present study, we used the synthetic bacterial lipopeptide Pam3CysSK4, a selective TLR2 agonist, to induce meningeal inflammation in rodents. In a 6-h rat model, intrathecal application of Pam3CysSK4 caused influx of leukocytes into the cerebrospinal fluid (CSF) and induced a marked increase of regional cerebral blood flow and intracranial pressure. In wild-type mice, we observed CSF pleocytosis and an increased number of apoptotic neurons in the dentate gyrus 24 h after intrathecal challenge. Inflammation and associated neuronal loss were absent in TLR2 knockout mice. In purified neurons, cytotoxicity of Pam3CysSK4 itself was not observed. Exposure of microglia to Pam3CysSK4 induced neurotoxic properties in the supernatant of wild-type, but not TLR2-deficient microglia. We conclude that TLR2-mediated signaling is sufficient to induce the host-dependent key features of acute bacterial meningitis. Therefore, synthetic lipopeptides are a highly specific tool to study mechanisms of TLR2-driven neurodegeneration in vivo.
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Affiliation(s)
- Olaf Hoffmann
- Department of Neurology, Center for Anatomy, Charité-Universitätsmedizin Berlin, Germany
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Phadke AP, Akangire G, Park SJ, Lira SA, Mehrad B. The role of CC chemokine receptor 6 in host defense in a model of invasive pulmonary aspergillosis. Am J Respir Crit Care Med 2007; 175:1165-72. [PMID: 17379855 PMCID: PMC1899275 DOI: 10.1164/rccm.200602-256oc] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
RATIONALE Invasive aspergillosis is a severe fungal infection afflicting immunocompromised patients, particularly patients with neutrophil defects. CCR6, a beta-chemokine receptor, mediates migration of dendritic cells (DCs) and several lymphocyte subsets to sites of epithelial inflammation, but its role in infections has not been examined extensively. OBJECTIVES To test the hypothesis that CCR6-mediated leukocyte recruitment is necessary for effective host defense in neutropenic hosts with invasive pulmonary aspergillosis. METHODS Neutropenic wild-type mice and mice with targeted deletion of CCR6 were infected with Aspergillus fumigatus. The host responses to the infection were compared in vivo and leukocyte responses to the fungus were examined in vitro. MEASUREMENTS AND MAIN RESULTS In the context of infection, immature myeloid DCs were the major population of CCR6-expressing cells in the lungs. As compared with wild-type animals, CCR6-deficient mice developed a more severe infection when challenged with A. fumigatus conidia, as documented by a higher mortality rate and greater lung fungal burden. This was associated with reduced accumulation of DCs in the lungs. CCR6-deficient and wild-type DCs did not differ in their phagocytosis of conidia, cytokine response, or maturation in vitro. In adoptive transfer experiments, however, DCs from CCR6-deficient donors showed lesser accumulation in the lungs of infected mice as compared with wild-type cells, and transfer of wild-type, but not CCR6-deficient, DCs resulted in attenuated severity of infection in CCR6-deficient recipients. CONCLUSIONS Taken together, these results implicate CCR6-mediated DC influx into the lung in the initial host defense in invasive aspergillosis.
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Affiliation(s)
- Anagha P Phadke
- Division of Pulmonary and Critical Care Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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38
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García-Suárez MDM, Flórez N, Astudillo A, Vázquez F, Villaverde R, Fabrizio K, Pirofski LA, Méndez FJ. The role of pneumolysin in mediating lung damage in a lethal pneumococcal pneumonia murine model. Respir Res 2007; 8:3. [PMID: 17257395 PMCID: PMC1790890 DOI: 10.1186/1465-9921-8-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2006] [Accepted: 01/26/2007] [Indexed: 01/28/2023] Open
Abstract
Background Intranasal inoculation of Streptococcus pneumoniae D39 serotype 2 causes fatal pneumonia in mice. The cytotoxic and inflammatory properties of pneumolysin (PLY) have been implicated in the pathogenesis of pneumococcal pneumonia. Methods To examine the role of PLY in this experimental model we performed ELISA assays for PLY quantification. The distribution patterns of PLY and apoptosis were established by immunohistochemical detection of PLY, caspase-9 activity and TUNEL assay on tissue sections from mice lungs at various times, and the results were quantified with image analysis. Inflammatory and apoptotic cells were also quantified on lung tissue sections from antibody treated mice. Results In bronchoalveolar lavages (BAL), total PLY was found at sublytic concentrations which were located in alveolar macrophages and leukocytes. The bronchoalveolar epithelium was PLY-positive, while the vascular endothelium was not PLY reactive. The pattern and extension of cellular apoptosis was similar. Anti-PLY antibody treatment decreased the lung damage and the number of apoptotic and inflammatory cells in lung tissues. Conclusion The data strongly suggest that in vivo lung injury could be due to the pro-apoptotic and pro-inflammatory activity of PLY, rather than its cytotoxic activity. PLY at sublytic concentrations induces lethal inflammation in lung tissues and is involved in host cell apoptosis, whose effects are important to pathogen survival.
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Affiliation(s)
- María del Mar García-Suárez
- Área de Microbiología, Departamento de Biología Funcional, Instituto Universitario de Biotecnología de Asturias (IUBA), Universidad de Oviedo; 33006 Oviedo, Asturias, Spain
| | - Noelia Flórez
- Área de Microbiología, Departamento de Biología Funcional, Instituto Universitario de Biotecnología de Asturias (IUBA), Universidad de Oviedo; 33006 Oviedo, Asturias, Spain
| | - Aurora Astudillo
- Laboratorio de Anatomía Patológica, Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Universidad de Oviedo; 33006 Oviedo, Asturias, Spain
| | - Fernando Vázquez
- Área de Microbiología, Departamento de Biología Funcional, Instituto Universitario de Biotecnología de Asturias (IUBA), Universidad de Oviedo; 33006 Oviedo, Asturias, Spain
| | - Roberto Villaverde
- Área de Microbiología, Departamento de Biología Funcional, Instituto Universitario de Biotecnología de Asturias (IUBA), Universidad de Oviedo; 33006 Oviedo, Asturias, Spain
| | - Kevin Fabrizio
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA
| | - Liise-Anne Pirofski
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA
- Division of Infectious Diseases, Department of Medicine, Albert Einstein College of Medicine and Montefiore Medical Center, 1300 Morris Park Avenue, Bronx, New York 10461, USA
| | - Francisco J Méndez
- Área de Microbiología, Departamento de Biología Funcional, Instituto Universitario de Biotecnología de Asturias (IUBA), Universidad de Oviedo; 33006 Oviedo, Asturias, Spain
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Colino J, Snapper CM. Dendritic cell-derived exosomes express a Streptococcus pneumoniae capsular polysaccharide type 14 cross-reactive antigen that induces protective immunoglobulin responses against pneumococcal infection in mice. Infect Immun 2006; 75:220-30. [PMID: 17043104 PMCID: PMC1828418 DOI: 10.1128/iai.01217-06] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Exosomes activate T cells in vivo, but whether exosomes are able to induce humoral immune responses is still unknown. We found that dendritic cells, but not other immune cells, constitutively release an exosome-associated glycoconjugate that is cross-reactive with the capsular polysaccharide of Streptococcus pneumoniae type 14 (Cps14-CRA). Cps14-CRA was localized to the cholesterol-enriched microdomains or rafts of the exosomes and was mapped to the beta1-->6 branched N-acetyl-lactosamine derivatives of the Cps14-CRA. Injection of CFA-primed naive mice with purified dendritic cell exosomes induced immunoglobulin (Ig) anti-Cps14 responses composed predominantly of IgM, IgG3, and IgG1. These responses were associated with protection against a lethal challenge with live S. pneumoniae type 14, but not with type 3 bacteria, and was correlated with the titer of elicited IgM and IgG3 anti-Cps14. These data show, for the first time, that exosomes can induce a humoral immune response to an associated unprocessed, autologous antigen. Although anti-Cps14 Ig responses are specifically demonstrated, these could reflect a broader mechanism that modulates both natural immunity and autoimmunity to other glycotopes.
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Affiliation(s)
- Jesus Colino
- Department of Pathology, Uniformed Services University of the Health Sciences (USUHS), 4301 Jones Bridge Road, Bethesda, MD 20814, USA
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40
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Colino J, Snapper CM. Exosomes from Bone Marrow Dendritic Cells Pulsed with Diphtheria Toxoid Preferentially Induce Type 1 Antigen-Specific IgG Responses in Naive Recipients in the Absence of Free Antigen. THE JOURNAL OF IMMUNOLOGY 2006; 177:3757-62. [PMID: 16951336 DOI: 10.4049/jimmunol.177.6.3757] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Exosomes derived from dendritic cells (DC) activate T cells in vivo, but whether exosomes are able to induce and/or modulate humoral immune responses is still unknown. We show that murine bone marrow DC pulsed in vitro with an intact protein (diphtheria toxoid (DT)) produce exosomes that induce, in the absence of free protein, in vivo Ig responses specific for DT in naive recipients. Furthermore, these exosomes stimulate secondary IgG anti-DT responses in mice primed with intact DT. Exosomes from mature, relative to immature, DC were more effective at inducing primary, although not secondary, IgG anti-DT responses. Whereas intact DT preferentially induced a type 2 (IgG1) anti-DT response, exosomes from DT-pulsed bone marrow DC favored induction of type 1 (IgG2b and IgG2a) DT-specific IgG. These results are the first to demonstrate the ability of exosomes derived from Ag-pulsed DC to induce and modulate Ag-specific humoral immunity in vivo.
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Affiliation(s)
- Jesus Colino
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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41
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Velan B, Bar-Haim E, Zauberman A, Mamroud E, Shafferman A, Cohen S. Discordance in the effects of Yersinia pestis on the dendritic cell functions manifested by induction of maturation and paralysis of migration. Infect Immun 2006; 74:6365-76. [PMID: 16923789 PMCID: PMC1695518 DOI: 10.1128/iai.00974-06] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The encounter between invading microorganisms and dendritic cells (DC) triggers a series of events which include uptake and degradation of the microorganism, induction of a maturation process, and enhancement of DC migration to the draining lymph nodes. Various pathogens have developed strategies to counteract these events as a measure to evade the host defense. In the present study we found that interaction of the Yersinia pestis EV76 strain with DC has no effect on cell viability and is characterized by compliance with effective maturation, which is manifested by surface display of major histocompatibility complex class II, of costimulatory markers, and of the chemokine receptor CCR7. This is in contrast to maturation inhibition and cell death induction exerted by the related species Yersinia enterocolitica WA O:8. Y. pestis interactions with DC were found, however, to impair functions related to cytoskeleton rearrangement. DC pulsed with Y. pestis failed to adhere to solid surfaces and to migrate toward the chemokine CCL19 in an in vitro transmembrane assay. Both effects were dependent on the presence of the pCD1 virulence plasmid and on a bacterial growth shift to 37 degrees C prior to infection. Moreover, while instillation of a pCD1-cured Y. pestis strain into mouse airways triggered effective transport of alveolar DC to the mediastinal lymph node, instillation of Y. pestis harboring the plasmid failed to do so. Taken together, these results suggest that virulence plasmid-dependent impairment of DC migration is the major mechanism utilized by Y. pestis to subvert DC function.
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Affiliation(s)
- Baruch Velan
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, P.O. Box 19, Ness-Ziona 74100, Israel.
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42
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Chabot-Roy G, Willson P, Segura M, Lacouture S, Gottschalk M. Phagocytosis and killing of Streptococcus suis by porcine neutrophils. Microb Pathog 2006; 41:21-32. [PMID: 16714092 DOI: 10.1016/j.micpath.2006.04.001] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2006] [Revised: 03/28/2006] [Accepted: 04/04/2006] [Indexed: 11/19/2022]
Abstract
Streptococcus suis serotype 2 is an important swine pathogen responsible for diverse infections, mainly meningitis. Virulence factors and the pathogenesis of infection are not well understood. Neutrophils may play an important role in the pathogenesis of infection given that infiltration by neutrophils and mononuclear cells are frequently observed in lesions caused by S. suis. The objective of this work was to study the interactions between S. suis serotype 2 and porcine neutrophils. Results showed that suilysin is toxic to neutrophils and this could help S. suis evade innate immunity. Moreover, suilysin appears to affect complement-dependent killing by decreasing the opsonization of S. suis and the bactericidal capacity of neutrophils. Our results confirm that capsule polysaccharide protects S. suis against killing and phagocytosis by neutrophils. We also showed that the presence of specific IgG against S. suis serotype 2 promoted killing by neutrophils, indicating that the induction of a strong humoral response is beneficial for clearance of this pathogen.
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Affiliation(s)
- Geneviève Chabot-Roy
- Groupe de recherche sur les maladies infectieuses du porc (GREMIP), Faculté de médecine vétérinaire, Université de Montréal, 3200 Sicotte, St-Hyacinthe, Qué., Canada J2S 2M2
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Marriott HM, Dockrell DH. Streptococcus pneumoniae: the role of apoptosis in host defense and pathogenesis. Int J Biochem Cell Biol 2006; 38:1848-54. [PMID: 16844403 DOI: 10.1016/j.biocel.2006.06.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2006] [Revised: 05/30/2006] [Accepted: 06/05/2006] [Indexed: 01/29/2023]
Abstract
Programmed cell death or apoptosis is a recognised feature of infection with Streptococcus pneumoniae, and is observed during pneumococcal meningitis and pneumonia. The cholesterol-dependent cytolysin, pneumolysin, is a major trigger of apoptosis in the brain in association with pneumococcal production of hydrogen peroxide. Pneumococcal cell wall is also an important stimulus for apoptosis. Microbial factors and host factors combine in causing apoptosis in the brain, with hippocampal neurons being particularly susceptible. In pulmonary infection epithelial cell apoptosis contributes to tissue injury but macrophage apoptosis may benefit the host, aiding microbial killing and downregulating the inflammatory response. During sepsis lymphocyte apoptosis may be harmful to the host while dendritic cell apoptosis may limit the generation of an adaptive immune response during infection. Apoptosis induction may be harmful or potentially beneficial during pneumococcal infection and understanding its function in each setting is essential to allow specific therapeutic intervention.
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Affiliation(s)
- Helen M Marriott
- Division of Genomic Medicine, F-Floor, University of Sheffield, Beech Hill Road, Sheffield S10 2RX, UK
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Hoarau C, Lagaraine C, Martin L, Velge-Roussel F, Lebranchu Y. Supernatant of Bifidobacterium breve induces dendritic cell maturation, activation, and survival through a Toll-like receptor 2 pathway. J Allergy Clin Immunol 2006; 117:696-702. [PMID: 16522473 DOI: 10.1016/j.jaci.2005.10.043] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2005] [Revised: 10/28/2005] [Accepted: 10/31/2005] [Indexed: 12/31/2022]
Abstract
BACKGROUND Commensal gut bacteria are essential for the development and maintenance of the gut's immune system. Some bacteria strains, such as Lactobacillus and Bifidobacterium species, have been reported to provide protection from allergic and inflammatory bowel diseases. However, the interactions between these commensal bacteria and the immune system are largely unknown. OBJECTIVE We studied the effects of a supernatant from the culture of B breve C50 (BbC50) on the maturation, activation, and survival of human dendritic cells (DCs). METHODS DCs were differentiated from human monocytes with IL-4 and GM-CSF for 5 days and cultured with BbC50 supernatant (BbC50SN) or LPS for 2 days. RESULTS BbC50SN induced DC maturation, with increase in CD83, CD86, and HLA-DR expression. We also showed, for the first time, that BbC50SN prolonged DC survival, with high IL-10 and low IL-12 production compared with that seen in LPS-DCs. Moreover, BbC50SN inhibited the effects of LPS on DCs, both in terms of IL-12 production and in terms of survival. The prolonged DC survival was independent of IL-10 production and nuclear factor kappaB pathway but was associated with an upregulation of Bcl-xL and Phospho-Bad. Finally, BbC50SN induced activation of Toll-like receptor 2 (TLR2)-transfected cells in contrast to TLR4-, TLR7-, and TLR9-transfected cells. CONCLUSION The supernatant of B breve C50 can induce DC maturation and prolonged DC survival through TLR2, with high IL-10 production. These properties might correspond to a regulatory DC profile, which could limit the excessive TH1 response and control the excessive TH2 polarization observed in atopic newborns.
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Affiliation(s)
- Cyrille Hoarau
- Université François-Rabelais de Tours, JE2448 Cellules Dendritiques & Greffes, France
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Kojo S, Seino KI, Harada M, Watarai H, Wakao H, Uchida T, Nakayama T, Taniguchi M. Induction of regulatory properties in dendritic cells by Valpha14 NKT cells. THE JOURNAL OF IMMUNOLOGY 2005; 175:3648-55. [PMID: 16148109 DOI: 10.4049/jimmunol.175.6.3648] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Valpha14 NKT cells exhibit various immune regulatory properties in vivo, but their precise mechanisms remain to be solved. In this study, we demonstrate the mechanisms of generation of regulatory dendritic cells (DCs) by stimulation of Valpha14 NKT cells in vivo. After repeated injection of alpha-galactosylceramide (alpha-GalCer) into mice, splenic DCs acquired properties of regulatory DCs in IL-10-dependent fashion, such as nonmatured phenotypes and increased IL-10 but reduced IL-12 production. The unique cytokine profile in these DCs appears to be regulated by ERK1/2 and IkappaB(NS). These DCs also showed an ability to suppress the development of experimental allergic encephalomyelitis by generating IL-10-producing regulatory CD4 T cells in vivo. These findings contribute to explaining how Valpha14 NKT cells regulate the immune responses in vivo.
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Affiliation(s)
- Satoshi Kojo
- Laboratory for Immune Regulation, Research Center for Allergy and Immunology (RCAI), Institute of Physical and Chemical Research (RIKEN), Kanagawa, Japan
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46
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Srivastava A, Henneke P, Visintin A, Morse SC, Martin V, Watkins C, Paton JC, Wessels MR, Golenbock DT, Malley R. The apoptotic response to pneumolysin is Toll-like receptor 4 dependent and protects against pneumococcal disease. Infect Immun 2005; 73:6479-87. [PMID: 16177320 PMCID: PMC1230904 DOI: 10.1128/iai.73.10.6479-6487.2005] [Citation(s) in RCA: 137] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Pneumolysin, the cholesterol-dependent cytolysin of Streptococcus pneumoniae, induces inflammatory and apoptotic events in mammalian cells. Toll-like receptor 4 (TLR4) confers resistance to pneumococcal infection via its interaction with pneumolysin, but the underlying mechanisms remain to be identified. In the present study, we found that pneumolysin-induced apoptosis is also mediated by TLR4 and confers protection against invasive disease. The interaction between TLR4 and pneumolysin is direct and specific; ligand-binding studies demonstrated that pneumolysin binds to TLR4 but not to TLR2. Involvement of TLR4 in pneumolysin-induced apoptosis was demonstrated in several complementary experiments. First, macrophages from wild-type mice were significantly more prone to pneumolysin-induced apoptosis than cells from TLR4-defective mice. In gain-of-function experiments, we found that epithelial cells expressing TLR4 and stimulated with pneumolysin were more likely to undergo apoptosis than cells expressing TLR2. A specific TLR4 antagonist, B1287, reduced pneumolysin-mediated apoptosis in wild-type cells. This apoptotic response was also partially caspase dependent as preincubation of cells with the pan-caspase inhibitor zVAD-fmk reduced pneumolysin-induced apoptosis. Finally, in a mouse model of pneumococcal infection, pneumolysin-producing pneumococci elicited significantly more upper respiratory tract cell apoptosis in wild-type mice than in TLR4-defective mice, and blocking apoptosis by administration of zVAD-fmk to wild-type mice resulted in a significant increase in mortality following nasopharyngeal pneumococcal exposure. Overall, our results strongly suggest that protection against pneumococcal disease is dependent on the TLR4-mediated enhancement of pneumolysin-induced apoptosis.
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Affiliation(s)
- Amit Srivastava
- Division of Infectious Diseases, Department of Medicine, Children's Hospital, Boston, MA 02115, USA
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47
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De Trez C, Pajak B, Brait M, Glaichenhaus N, Urbain J, Moser M, Lauvau G, Muraille E. TLR4 and Toll-IL-1 Receptor Domain-Containing Adapter-Inducing IFN-β, but Not MyD88, Regulate Escherichia coli-Induced Dendritic Cell Maturation and Apoptosis In Vivo. THE JOURNAL OF IMMUNOLOGY 2005; 175:839-46. [PMID: 16002681 DOI: 10.4049/jimmunol.175.2.839] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Dendritic cells (DC) are short-lived, professional APCs that play a central role in the generation of adaptive immune responses. Induction of efficient immune responses is dependent on how long DCs survive in the host. Therefore, the regulation of DC apoptosis in vivo during infection remains an important question that requires further investigation. The impact of Escherichia coli bacteremia on DCs has never been analyzed. We show here that i.v. or i.p. administration of live or heat-killed E. coli in mice induces splenic DC migration, maturation, and apoptosis. We further characterize which TLR and Toll-IL-1R (TIR)-containing adaptor molecules regulate these processes in vivo. In this model, DC maturation is impaired in TLR2(-/-), TLR4(-/-) and TIR domain-containing adapter-inducing IFN-beta (TRIF)(-/-) mice. In contrast, DC apoptosis is reduced only in TLR4(-/-) and TRIF(-/-) mice. As expected, DC apoptosis induced by the TLR4 ligand LPS is also abolished in these mice. Injection of the TLR9 ligand CpG-oligodeoxynucleotide (synthetic bacterial DNA) induces DC migration and maturation, but only modest DC apoptosis when compared with LPS and E. coli. Together, these results suggest that E. coli bacteremia directly impacts on DC maturation and survival in vivo through a TLR4-TRIF-dependent signaling pathway.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Adaptor Proteins, Vesicular Transport/deficiency
- Adaptor Proteins, Vesicular Transport/genetics
- Adaptor Proteins, Vesicular Transport/physiology
- Animals
- Antigens, Differentiation/biosynthesis
- Antigens, Differentiation/genetics
- Apoptosis/immunology
- Cell Differentiation/immunology
- Cell Movement/immunology
- Dendritic Cells/cytology
- Dendritic Cells/immunology
- Dendritic Cells/microbiology
- Escherichia coli/growth & development
- Escherichia coli/immunology
- Female
- Injections, Intravenous
- Interferon-beta/biosynthesis
- Membrane Glycoproteins/physiology
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Myeloid Differentiation Factor 88
- Receptors, Immunologic/biosynthesis
- Receptors, Immunologic/deficiency
- Receptors, Immunologic/genetics
- Receptors, Immunologic/physiology
- Receptors, Interleukin-1/physiology
- Signal Transduction/genetics
- Signal Transduction/immunology
- Spleen/cytology
- Spleen/immunology
- Spleen/microbiology
- Toll-Like Receptor 2
- Toll-Like Receptor 4
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Affiliation(s)
- Carl De Trez
- Laboratory of Animal Physiology, Institut de Biologie et de Médecine Moléculaire, Université Libre de Bruxelles, Gosselies, Belgium
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Bermpohl D, Halle A, Freyer D, Dagand E, Braun JS, Bechmann I, Schröder NWJ, Weber JR. Bacterial programmed cell death of cerebral endothelial cells involves dual death pathways. J Clin Invest 2005; 115:1607-15. [PMID: 15902310 PMCID: PMC1088015 DOI: 10.1172/jci23223] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2004] [Accepted: 03/23/2005] [Indexed: 01/19/2023] Open
Abstract
Major barriers separating the blood from tissue compartments in the body are composed of endothelial cells. Interaction of bacteria with such barriers defines the course of invasive infections, and meningitis has served as a model system to study endothelial cell injury. Here we report the impressive ability of Streptococcus pneumoniae, clinically one of the most important pathogens, to induce 2 morphologically distinct forms of programmed cell death (PCD) in brain-derived endothelial cells. Pneumococci and the major cytotoxins H2O2 and pneumolysin induce apoptosis-like PCD independent of TLR2 and TLR4. On the other hand, pneumococcal cell wall, a major proinflammatory component, causes caspase-driven classical apoptosis that is mediated through TLR2. These findings broaden the scope of bacterial-induced PCD, link these effects to innate immune TLRs, and provide insight into the acute and persistent phases of damage during meningitis.
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Affiliation(s)
- Daniela Bermpohl
- Department of Neurology, Center of Anatomy, Charité--Universitätsmedizin Berlin, Berlin, Germany
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Khan AQ, Chen Q, Wu ZQ, Paton JC, Snapper CM. Both innate immunity and type 1 humoral immunity to Streptococcus pneumoniae are mediated by MyD88 but differ in their relative levels of dependence on toll-like receptor 2. Infect Immun 2005; 73:298-307. [PMID: 15618166 PMCID: PMC538967 DOI: 10.1128/iai.73.1.298-307.2005] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Little is known regarding the role of Toll-like receptors (TLRs) in regulating protein- and polysaccharide-specific immunoglobulin (Ig) isotype production in response to an in vivo challenge with an extracellular bacterium. In this report we demonstrate that MyD88(-/-), but not TLR2(-/-), mice are markedly defective in their induction of multiple splenic proinflammatory cytokine- and chemokine-specific mRNAs after intraperitoneal (i.p.) challenge with heat-killed Streptococcus pneumoniae capsular type 14 (S. pneumoniae type 14). This is correlated with analogous responses in splenic cytokine protein release in vitro following addition of S. pneumoniae type 14. Consistent with these data, naive MyD88(-/-), but not TLR2(-/-), mice are more sensitive to killing following i.p. challenge with live S. pneumoniae type 14, relative to responses in wild-type mice. However, prior immunization of MyD88(-/-) mice with heat-killed S. pneumoniae type 14 protects against an otherwise-lethal challenge with live S. pneumoniae type 14. Surprisingly, both MyD88(-/-) and TLR2(-/-) mice exhibit striking and equivalent defects in elicitation of type 1 IgG isotypes (IgG3, IgG2b, and IgG2a), but not the type 2 IgG isotype, IgG1, specific for several protein and polysaccharide antigens, in response to i.p. challenge with heat-killed S. pneumoniae type 14. Of note, the type 1 IgG isotype titers specific for pneumococcal surface protein A are reduced in MyD88(-/-) mice but not TLR2(-/-) mice. These data suggest that distinct TLRs may differentially regulate innate versus adaptive humoral immunity to intact S. pneumoniae and are the first to implicate a role for TLR2 in shaping an in vivo type 1 IgG humoral immune response to a gram-positive extracellular bacterium.
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Affiliation(s)
- Abdul Q Khan
- Department of Pathology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Rd., Bethesda, MD 20814, USA
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50
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Zweigner J, Jackowski S, Smith SH, Van Der Merwe M, Weber JR, Tuomanen EI. Bacterial inhibition of phosphatidylcholine synthesis triggers apoptosis in the brain. ACTA ACUST UNITED AC 2004; 200:99-106. [PMID: 15238609 PMCID: PMC2213312 DOI: 10.1084/jem.20032100] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Streptococcus pneumoniae is the most common cause of bacterial meningitis of high mortality and morbidity. Neurological sequelae include paralysis, mental retardation, and learning disorders. In humans, neurons of the hippocampus undergo apoptosis as a result of meningitis. Phosphatidylcholine (PtdCho) is an essential component of mammalian cell membranes and PtdCho deficiency, either due to chemicals or altered nutrition, leads to apoptosis, especially in hippocampal neurons. We show that apoptosis of a variety of brain cells after pneumococcal infection arises from inhibition of PtdCho biosynthesis, the first such activity described for a bacterium. Apoptosis inhibitors did not prevent the bacterial-dependent inhibition of PtdCho biosynthesis. Supplementation with exogenous lyso-phosphatidylcholine prevents cell death and treatment of mice with cytidine diphosphocholine attenuates hippocampal damage during meningitis, even after the onset of infection. We conclude that bacterial inhibition of PtdCho biosynthesis activates an apoptotic cascade that is a causative event in pathogenesis and amenable to therapeutic intervention.
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Affiliation(s)
- Janine Zweigner
- Department of Infectious Diseases, St. Jude Children's Research Hospital, 332 North Lauderdale Street, Memphis, TN 38105, USA
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