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Eisentraut M, Sabri A, Kress H. The spatial resolution limit of phagocytosis. Biophys J 2023; 122:868-879. [PMID: 36703557 PMCID: PMC10027436 DOI: 10.1016/j.bpj.2023.01.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 01/05/2023] [Accepted: 01/23/2023] [Indexed: 01/27/2023] Open
Abstract
Antibody-opsonized bacteria interact with Fc receptors in macrophages and trigger signaling cascades, which induce phagocytosis. The signaling pathways ultimately lead to actin polymerization that induces the protrusion of the membrane around the bacterium until it is completely engulfed. Although many proteins involved in the phagocytic cup formation have already been identified, it is still unclear how far the initial stimulus created by the bacterium-cell contact propagates in the cell. We hypothesize that this spreading distance is closely related to the spatial resolution limit of phagocytosis, the smallest distance in which two stimuli can be differentiated. Here, we probe this resolution limit by using holographic optical tweezers to attach pairs of immunoglobulin G-coated polystyrene microparticles (as models for opsonized bacteria) to murine macrophages in distances ranging from zero to several micrometers. By using 2-μm-sized particles, we found that the particles can be internalized jointly into one phagosome if they are attached to the cell very close together, but that they are taken up separately if they are attached far from each other. To explain this, we developed a model of the signaling process, which predicts the probabilities for separate uptake for different particle sizes and distances using cellular parameters including the average receptor distance. We tested the model by measuring the separate uptake probabilities for particles with a diameter of 1 to 3 μm and for cells with reduced numbers of Fcγ receptors and found very good agreement. Our model shows that the phagocytic uptake behavior can be explained by assuming an effective phagocytic signaling range of about 500 nm. Interestingly, this value corresponds to the lower size limit of phagocytosis. Our work provides quantitative access to spatial parameters of cellular signaling during phagocytosis and thereby contributes to a more quantitative understanding of cellular information processing.
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Affiliation(s)
| | - Adal Sabri
- Biological Physics, University of Bayreuth, Bayreuth, Germany
| | - Holger Kress
- Biological Physics, University of Bayreuth, Bayreuth, Germany.
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2
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Cell-Level Analysis Visualizing Photodynamic Therapy with Porphylipoprotein and Talaporphyrin Sodium. Int J Mol Sci 2022; 23:ijms232113140. [PMID: 36361927 PMCID: PMC9655257 DOI: 10.3390/ijms232113140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/25/2022] [Accepted: 10/26/2022] [Indexed: 12/20/2022] Open
Abstract
We revealed the difference in the mechanism of photodynamic therapy (PDT) between two photosensitizers: porphylipoprotein (PLP), which has recently attracted attention for its potential to be highly effective in treating cancer, and talaporphyrin sodium (NPe6). (1) NPe6 accumulates in lysosomes, whereas PLP is incorporated into phagosomes formed by PLP injection. (2) PDT causes NPe6 to generate reactive oxygen species, thereby producing actin filaments and stress fibers. In the case of PLP, however, reactive oxygen species generated by PDT remain in the phagosomes until the phagosomal membrane is destroyed, which delays the initiation of RhoA activation and RhoA*/ROCK generation. (4) After the disruption of the phagosomal membrane, however, the outflow of various reactive oxygen species accelerates the production of actin filaments and stress fibers, and blebbing occurs earlier than in the case of NPe6. (5) PLP increases the elastic modulus of cells without RhoA activity in the early stage. This is because phagosomes are involved in polymerizing actin filaments and pseudopodia formation. Considering the high selectivity and uptake of PLP into cancer cells, a larger effect with PDT can be expected by skillfully combining the newly discovered characteristics, such as the appearance of a strong effect at an early stage.
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3
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Jiang L, Poon IKH. Methods for monitoring the progression of cell death, cell disassembly and cell clearance. Apoptosis 2020; 24:208-220. [PMID: 30684146 DOI: 10.1007/s10495-018-01511-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Cell death through apoptosis, necrosis, necroptosis and pyroptosis, as well as the clearance of dead cells are crucial biological processes in the human body. Likewise, disassembly of dying cells during apoptosis to generate cell fragments known as apoptotic bodies may also play important roles in regulating cell clearance and intercellular communication. Recent advances in the field have led to the development of new experimental systems to identify cells at different stages of cell death, measure the levels of apoptotic cell disassembly, and monitor the cell clearance process using a range of in vitro, ex vivo and in vivo models. In this article, we will provide a comprehensive review of the methods for monitoring the progression of cell death, cell disassembly and cell clearance.
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Affiliation(s)
- Lanzhou Jiang
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, 3086, Australia
| | - Ivan K H Poon
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, 3086, Australia.
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4
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Venosa A, Smith LC, Murray A, Banota T, Gow AJ, Laskin JD, Laskin DL. Regulation of Macrophage Foam Cell Formation During Nitrogen Mustard (NM)-Induced Pulmonary Fibrosis by Lung Lipids. Toxicol Sci 2019; 172:344-358. [PMID: 31428777 PMCID: PMC6876262 DOI: 10.1093/toxsci/kfz187] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Nitrogen mustard (NM) is a vesicant known to target the lung, causing acute injury which progresses to fibrosis. Evidence suggests that activated macrophages contribute to the pathologic response to NM. In these studies, we analyzed the role of lung lipids generated following NM exposure on macrophage activation and phenotype. Treatment of rats with NM (0.125 mg/kg, i.t.) resulted in a time-related increase in enlarged vacuolated macrophages in the lung. At 28 days postexposure, macrophages stained positively for Oil Red O, a marker of neutral lipids. This was correlated with an accumulation of oxidized phospholipids in lung macrophages and epithelial cells and increases in bronchoalveolar lavage fluid (BAL) phospholipids and cholesterol. RNA-sequencing and immunohistochemical analysis revealed that lipid handling pathways under the control of the transcription factors liver-X receptor (LXR), farnesoid-X receptor (FXR), peroxisome proliferator-activated receptor (PPAR)-ɣ, and sterol regulatory element-binding protein (SREBP) were significantly altered following NM exposure. Whereas at 1-3 days post NM, FXR and the downstream oxidized low-density lipoprotein receptor, Cd36, were increased, Lxr and the lipid efflux transporters, Abca1 and Abcg1, were reduced. Treatment of naïve lung macrophages with phospholipid and cholesterol enriched large aggregate fractions of BAL prepared 3 days after NM exposure resulted in upregulation of Nos2 and Ptgs2, markers of proinflammatory activation, whereas large aggregate fractions prepared 28 days post NM upregulated expression of the anti-inflammatory markers, Il10, Cd163, and Cx3cr1, and induced the formation of lipid-laden foamy macrophages. These data suggest that NM-induced alterations in lipid handling and metabolism drive macrophage foam cell formation, potentially contributing to the development of pulmonary fibrosis.
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Affiliation(s)
- Alessandro Venosa
- Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy
| | - Ley Cody Smith
- Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy
| | - Alexa Murray
- Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy
| | - Tanvi Banota
- Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy
| | - Andrew J Gow
- Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy
| | - Jeffrey D Laskin
- Department of Environmental and Occupational Health, School of Public Health, Rutgers University, Piscataway, New Jersey 08854
| | - Debra L Laskin
- Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy
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5
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In vivo Proteomics Approaches for the Analysis of Bacterial Adaptation Reactions in Host-Pathogen Settings. Methods Mol Biol 2018. [PMID: 30259489 DOI: 10.1007/978-1-4939-8695-8_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Proteome profiling of bacteria internalized by host cells is still a challenging task, due to low amounts of bacterial proteins in host-pathogen settings and the high amounts of contaminating host proteins. Here, we describe a workflow for the enrichment of intracellular bacteria by fluorescence activated cell sorting which in combination with highly sensitive LC-MS/MS allows monitoring of about 1200 proteins from 2 to 4 × 106 internalized bacterial cells as starting material.
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6
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Salmonella-containing vacuole development in avian cells and characteristic of cigR in Salmonella enterica serovar Pullorum replication within macrophages. Vet Microbiol 2018; 223:65-71. [PMID: 30173754 DOI: 10.1016/j.vetmic.2018.07.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 07/16/2018] [Accepted: 07/18/2018] [Indexed: 01/03/2023]
Abstract
Salmonella enterica serovar Pullorum (S. Pullorum) is one of the host-restricted serotypes causing systemic infection in poultry. Survival in macrophages is one of the mechanisms underlying the persistent infection of S. Pullorum in hosts. Formation of Salmonella-containing vacuole (SCV) is essential for bacteria to be concealed in macrophages. In this study, confocal microscopy was applied to detect the SCV development by S. Pullorum in the chicken hepatocellular carcinoma cell line LMH and the macrophage cell line HD-11, respectively. The results showed that macrophages were more appropriate for the SCV maturation during S. Pullorum infection compared to epithelial cells. We evaluated the role of the CigR effector protein in the formation of SCVs. CigR is a membrane-binding protein, which is one of the type III secretion system 2 (T3SS2) effectors encoded within Salmonella pathogenicity island 3 (SPI3). The deletion of cigR in S. Typhimurium and S. Pullorum enhanced bacterial virulence to both mice and chickens. To analyze the influence of CigR on the SCV development during S. Pullorum infection, this study compared the formation of SCVs by using S. Pullorum C79-13 and the cigR deleted strain C79-13ΔcigR. Compared to the wild type strain, the loss of cigR gene in strain C79-13ΔcigR caused a four-fold increase in the recruitment ability of the SCV marker protein Rab7 in infected macrophages after 30 min, 5 h, and 16 h post-infection. In addition, infection and proliferation of strain C79-13ΔcigR in the avian macrophage cell line HD-11 was higher than that of the wild type strain. Our findings suggest that CigR is an anti-virulence effector inhibiting replication of S. Pullorum and SCV development in macrophages.
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Allgood SC, Neunuebel MR. The recycling endosome and bacterial pathogens. Cell Microbiol 2018; 20:e12857. [PMID: 29748997 PMCID: PMC5993623 DOI: 10.1111/cmi.12857] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 04/05/2018] [Accepted: 04/27/2018] [Indexed: 12/29/2022]
Abstract
Bacterial pathogens have developed a wide range of strategies to survive within human cells. A number of pathogens multiply in a vacuolar compartment, whereas others can rupture the vacuole and replicate in the host cytosol. A common theme among many bacterial pathogens is the use of specialised secretion systems to deliver effector proteins into the host cell. These effectors can manipulate the host's membrane trafficking pathways to remodel the vacuole into a replication-permissive niche and prevent degradation. As master regulators of eukaryotic membrane traffic, Rab GTPases are principal targets of bacterial effectors. This review highlights the manipulation of Rab GTPases that regulate host recycling endocytosis by several bacterial pathogens, including Chlamydia pneumoniae, Chlamydia trachomatis, Shigella flexneri, Salmonella enterica serovar Typhimurium, Uropathogenic Escherichia coli, and Legionella pneumophila. Recycling endocytosis plays key roles in a variety of cellular aspects such as nutrient uptake, immunity, cell division, migration, and adhesion. Though much remains to be understood about the molecular basis and the biological relevance of bacterial pathogens exploiting Rab GTPases, current knowledge supports the notion that endocytic recycling Rab GTPases are differentially targeted to avoid degradation and support bacterial replication. Thus, future studies of the interactions between bacterial pathogens and host endocytic recycling pathways are poised to deepen our understanding of bacterial survival strategies.
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Affiliation(s)
| | - M. Ramona Neunuebel
- Department of Biological Sciences, University of Delaware, Newark, Delaware, USA
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8
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Intracellular Growth of Bacterial Pathogens: The Role of Secreted Effector Proteins in the Control of Phagocytosed Microorganisms. Microbiol Spectr 2018; 3. [PMID: 27337278 DOI: 10.1128/microbiolspec.vmbf-0003-2014] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The ability of intracellular pathogens to subvert the host response, to facilitate invasion and subsequent infection, is the hallmark of microbial pathogenesis. Bacterial pathogens produce and secrete a variety of effector proteins, which are the primary means by which they exert control over the host cell. Secreted effectors work independently, yet in concert with each other, to facilitate microbial invasion, replication, and intracellular survival in host cells. In this review we focus on defined host cell processes targeted by bacterial pathogens. These include phagosome maturation and its subprocesses: phagosome-endosome and phagosome-lysosome fusion events, as well as phagosomal acidification, cytoskeleton remodeling, and lysis of the phagosomal membrane. We further describe the mode of action for selected effectors from six pathogens: the Gram-negative Legionella, Salmonella, Shigella, and Yersinia, the Gram-positive Listeria, and the acid-fast actinomycete Mycobacterium.
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9
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Keller S, Berghoff K, Kress H. Phagosomal transport depends strongly on phagosome size. Sci Rep 2017; 7:17068. [PMID: 29213131 PMCID: PMC5719076 DOI: 10.1038/s41598-017-17183-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 11/21/2017] [Indexed: 02/06/2023] Open
Abstract
Macrophages internalize pathogens for intracellular degradation. An important part of this process is the phagosomal transport from the cell periphery to the perinuclear region. Biochemical factors are known to influence the fate of phagosomes. Here, we show that the size of phagosomes also has a strong influence on their transport. We found that large phagosomes are transported persistently to the nucleus, whereas small phagosomes show strong bidirectional transport. We show that dynein motors play a larger role in the transport of large phagosomes, whereas actin filament-based motility plays a larger role in the transport of small phagosomes. Furthermore, we investigated the spatial distribution of dyneins and microtubules around phagosomes and hypothesize that dynein and microtubule density differences between the nucleus-facing side of phagosomes and the opposite side could explain part of the observed transport characteristics. Our findings suggest that a size-dependent cellular sorting mechanism might exist that supports macrophages in their immunological roles.
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Affiliation(s)
- S Keller
- Department of Physics, University of Bayreuth, Universitaetsstrasse 30, D-95440, Bayreuth, Germany.
| | - K Berghoff
- Department of Physics, University of Bayreuth, Universitaetsstrasse 30, D-95440, Bayreuth, Germany
| | - H Kress
- Department of Physics, University of Bayreuth, Universitaetsstrasse 30, D-95440, Bayreuth, Germany
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10
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Gutiérrez S, Wolke M, Plum G, Robinson N. Isolation of Salmonella typhimurium-containing Phagosomes from Macrophages. J Vis Exp 2017. [PMID: 29155747 DOI: 10.3791/56514] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Salmonella typhimurium is a facultative intracellular bacterium that causes gastroenteritis in humans. After invasion of the lamina propria, S. typhimurium bacteria are quickly detected and phagocytized by macrophages, and contained in vesicles known as phagosomes in order to be degraded. Isolation of S. typhimurium-containing phagosomes have been widely used to study how S. typhimurium infection alters the process of phagosome maturation to prevent bacterial degradation. Classically, the isolation of bacteria-containing phagosomes has been performed by sucrose gradient centrifugation. However, this process is time-consuming, and requires specialized equipment and a certain degree of dexterity. Described here is a simple and quick method for the isolation of S. typhimurium-containing phagosomes from macrophages by coating the bacteria with biotin-streptavidin-conjugated magnetic beads. Phagosomes obtained by this method can be suspended in any buffer of choice, allowing the utilization of isolated phagosomes for a broad range of assays, such as protein, metabolite, and lipid analysis. In summary, this method for the isolation of S. typhimurium-containing phagosomes is specific, efficient, rapid, requires minimum equipment, and is more versatile than the classical method of isolation by sucrose gradient-ultracentrifugation.
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Affiliation(s)
- Saray Gutiérrez
- Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne; Cologne Cluster of Excellence in Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne
| | - Martina Wolke
- Cologne Cluster of Excellence in Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne
| | - Georg Plum
- Cologne Cluster of Excellence in Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne
| | - Nirmal Robinson
- Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne; Cologne Cluster of Excellence in Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne;
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11
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Shaping the niche in macrophages: Genetic diversity of the M. tuberculosis complex and its consequences for the infected host. Int J Med Microbiol 2017; 308:118-128. [PMID: 28969988 DOI: 10.1016/j.ijmm.2017.09.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 09/09/2017] [Accepted: 09/11/2017] [Indexed: 12/12/2022] Open
Abstract
Pathogenic mycobacteria of the Mycobacterium tuberculosis complex (MTBC) have co-evolved with their individual hosts and are able to transform the hostile environment of the macrophage into a permissive cellular habitat. The impact of MTBC genetic variability has long been considered largely unimportant in TB pathogenesis. Members of the MTBC can now be distinguished into three major phylogenetic groups consisting of 7 phylogenetic lineages and more than 30 so called sub-lineages/subgroups. MTBC genetic diversity indeed influences the transmissibility and virulence of clinical MTBC isolates as well as the immune response and the clinical outcome. Here we review the genetic diversity and epidemiology of MTBC strains and describe the current knowledge about the host immune response to infection with MTBC clinical isolates using human and murine experimental model systems in vivo and in vitro. We discuss the role of innate cytokines in detail and portray two in our group recently developed approaches to characterize the intracellular niches of MTBC strains. Characterizing the niches and deciphering the strategies of MTBC strains to transform an antibacterial effector cell into a permissive cellular habitat offers the opportunity to identify strain- and lineage-specific key factors which may represent targets for novel antimicrobial or host directed therapies for tuberculosis.
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12
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13
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Dayam RM, Saric A, Shilliday RE, Botelho RJ. The Phosphoinositide-Gated Lysosomal Ca2+Channel, TRPML1, Is Required for Phagosome Maturation. Traffic 2015; 16:1010-26. [DOI: 10.1111/tra.12303] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 05/15/2015] [Accepted: 05/17/2015] [Indexed: 12/27/2022]
Affiliation(s)
- Roya M. Dayam
- Department of Chemistry and Biology; Ryerson University; Toronto Ontario M5B2K3 Canada
- Molecular Science Program; Ryerson University; Toronto Ontario M5B2K3 Canada
| | - Amra Saric
- Department of Chemistry and Biology; Ryerson University; Toronto Ontario M5B2K3 Canada
- Molecular Science Program; Ryerson University; Toronto Ontario M5B2K3 Canada
| | - Ryan E. Shilliday
- Department of Chemistry and Biology; Ryerson University; Toronto Ontario M5B2K3 Canada
| | - Roberto J. Botelho
- Department of Chemistry and Biology; Ryerson University; Toronto Ontario M5B2K3 Canada
- Molecular Science Program; Ryerson University; Toronto Ontario M5B2K3 Canada
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14
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Gilberti RM, Knecht DA. Macrophages phagocytose nonopsonized silica particles using a unique microtubule-dependent pathway. Mol Biol Cell 2014; 26:518-29. [PMID: 25428990 PMCID: PMC4310742 DOI: 10.1091/mbc.e14-08-1301] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Cells can take up particles by both opsonized and nonopsonized pathways. Silica and latex, but not zymosan, can be taken up by the nonopsonized pathway. Uptake of silica, but not latex, is toxic to macrophages. Nonopsonized phagocytosis is characterized and found to have key differences from the complement- and antibody-opsonized pathways. Silica inhalation leads to the development of the chronic lung disease silicosis. Macrophages are killed by uptake of nonopsonized silica particles, and this is believed to play a critical role in the etiology of silicosis. However, the mechanism of nonopsonized-particle uptake is not well understood. We compared the molecular events associated with nonopsonized- and opsonized-particle phagocytosis. Both Rac and RhoA GTPases are activated upon nonopsonized-particle exposure, whereas opsonized particles activate either Rac or RhoA. All types of particles quickly generate a PI(3,4,5)P3 and F-actin response at the particle attachment site. After formation of a phagosome, the events related to endolysosome-to-phagosome fusion do not significantly differ between the pathways. Inhibitors of tyrosine kinases, actin polymerization, and the phosphatidylinositol cascade prevent opsonized- and nonopsonized-particle uptake similarly. Inhibition of silica particle uptake prevents silica-induced cell death. Microtubule depolymerization abolished uptake of complement-opsonized and nonopsonized particles but not Ab-opsonized particles. Of interest, regrowth of microtubules allowed uptake of new nonopsonized particles but not ones bound to cells in the absence of microtubules. Although complement-mediated uptake requires macrophages to be PMA-primed, untreated cells phagocytose nonopsonized silica and latex. Thus it appears that nonopsonized-particle uptake is accomplished by a pathway with unique characteristics.
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Affiliation(s)
- Renée M Gilberti
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269
| | - David A Knecht
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269
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15
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Hill MS. Production possibility frontiers in phototroph:heterotroph symbioses: trade-offs in allocating fixed carbon pools and the challenges these alternatives present for understanding the acquisition of intracellular habitats. Front Microbiol 2014; 5:357. [PMID: 25101064 PMCID: PMC4101577 DOI: 10.3389/fmicb.2014.00357] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 06/25/2014] [Indexed: 11/13/2022] Open
Abstract
Intracellular habitats have been invaded by a remarkable diversity of organisms, and strategies employed to successfully reside in another species' cellular space are varied. Common selective pressures may be experienced in symbioses involving phototrophic symbionts and heterotrophic hosts. Here I refine and elaborate the Arrested Phagosome Hypothesis that proposes a mechanism that phototrophs use to gain access to their host's intracellular habitat. I employ the economic concept of production possibility frontiers (PPF) as a useful heuristic to clearly define the trade-offs that an intracellular phototroph is likely to face as it allocates photosynthetically-derived pools of energy. Fixed carbon can fuel basic metabolism/respiration, it can support mitotic division, or it can be translocated to the host. Excess photosynthate can be stored for future use. Thus, gross photosynthetic productivity can be divided among these four general categories, and natural selection will favor phenotypes that best match the demands presented to the symbiont by the host cellular habitat. The PPF highlights trade-offs that exist between investment in growth (i.e., mitosis) or residency (i.e., translocating material to the host). Insights gained from this perspective might help explain phenomena such as coral bleaching because deficits in photosynthetic production are likely to diminish a symbiont's ability to "afford" the costs of intracellular residency. I highlight deficits in our current understanding of host:symbiont interactions at the molecular, genetic, and cellular level, and I also discuss how semantic differences among scientists working with different symbiont systems may diminish the rate of increase in our understanding of phototrophic-based associations. I argue that adopting interdisciplinary (in this case, inter-symbiont-system) perspectives will lead to advances in our general understanding of the phototrophic symbiont's intracellular niche.
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Affiliation(s)
- Malcolm S Hill
- Department of Biology, Gottwald Science Center, University of Richmond Richmond, VA, USA
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16
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Whittingham JL, Blagova EV, Finn CE, Luo H, Miranda-CasoLuengo R, Turkenburg JP, Leech AP, Walton PH, Murzin AG, Meijer WG, Wilkinson AJ. Structure of the virulence-associated protein VapD from the intracellular pathogen Rhodococcus equi. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2014; 70:2139-51. [PMID: 25084333 PMCID: PMC4118825 DOI: 10.1107/s1399004714012632] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 05/30/2014] [Indexed: 01/17/2023]
Abstract
Rhodococcus equi is a multi-host pathogen that infects a range of animals as well as immune-compromised humans. Equine and porcine isolates harbour a virulence plasmid encoding a homologous family of virulence-associated proteins associated with the capacity of R. equi to divert the normal processes of endosomal maturation, enabling bacterial survival and proliferation in alveolar macrophages. To provide a basis for probing the function of the Vap proteins in virulence, the crystal structure of VapD was determined. VapD is a monomer as determined by multi-angle laser light scattering. The structure reveals an elliptical, compact eight-stranded β-barrel with a novel strand topology and pseudo-twofold symmetry, suggesting evolution from an ancestral dimer. Surface-associated octyl-β-D-glucoside molecules may provide clues to function. Circular-dichroism spectroscopic analysis suggests that the β-barrel structure is preceded by a natively disordered region at the N-terminus. Sequence comparisons indicate that the core folds of the other plasmid-encoded virulence-associated proteins from R. equi strains are similar to that of VapD. It is further shown that sequences encoding putative R. equi Vap-like proteins occur in diverse bacterial species. Finally, the functional implications of the structure are discussed in the light of the unique structural features of VapD and its partial structural similarity to other β-barrel proteins.
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Affiliation(s)
- Jean L. Whittingham
- Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5DD, England
| | - Elena V. Blagova
- Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5DD, England
| | - Ciaran E. Finn
- UCD School of Biomolecular and Biomedical Science and UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Haixia Luo
- UCD School of Biomolecular and Biomedical Science and UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Raúl Miranda-CasoLuengo
- UCD School of Biomolecular and Biomedical Science and UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Johan P. Turkenburg
- Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5DD, England
| | - Andrew P. Leech
- Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5DD, England
| | - Paul H. Walton
- Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5DD, England
| | - Alexey G. Murzin
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, England
| | - Wim G. Meijer
- UCD School of Biomolecular and Biomedical Science and UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Anthony J. Wilkinson
- Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5DD, England
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17
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Horn L, Leips J, Starz‐Gaiano M. Phagocytic ability declines with age in adult Drosophila hemocytes. Aging Cell 2014; 13:719-28. [PMID: 24828474 PMCID: PMC4116448 DOI: 10.1111/acel.12227] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/24/2014] [Indexed: 12/17/2022] Open
Abstract
Most multicellular organisms show a physiological decline in immune function with age. However, little is known about the mechanisms underlying these changes. We examined Drosophila melanogaster, an important model for identifying genes affecting innate immunity and senescence, to explore the role of phagocytosis in age-related immune dysfunction. We characterized the localized response of immune cells at the dorsal vessel to bacterial infection in 1-week- and 5-week-old flies. We developed a quantitative phagocytosis assay for adult Drosophila and utilized this to characterize the effect of age on phagocytosis in transgenic and natural variant lines. We showed that genes necessary for bacterial engulfment in other contexts are also required in adult flies. We found that blood cells from young and old flies initially engulf bacteria equally well, while cells from older flies accumulate phagocytic vesicles and thus are less capable of destroying pathogens. Our results have broad implications for understanding how the breakdown in cellular processes influences immune function with age.
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Affiliation(s)
- Lucas Horn
- Department of Biological Sciences University of Maryland Baltimore County Baltimore MD 21250USA
| | - Jeff Leips
- Department of Biological Sciences University of Maryland Baltimore County Baltimore MD 21250USA
| | - Michelle Starz‐Gaiano
- Department of Biological Sciences University of Maryland Baltimore County Baltimore MD 21250USA
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18
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Wang M, Zhao D, Yang Y, Liu J, Wang J, Yin X, Yang L, Zhou X. The cellular prion protein negatively regulates phagocytosis and cytokine expression in murine bone marrow-derived macrophages. PLoS One 2014; 9:e102785. [PMID: 25058617 PMCID: PMC4109954 DOI: 10.1371/journal.pone.0102785] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 06/23/2014] [Indexed: 11/19/2022] Open
Abstract
The cellular prion protein (PrPC) is a glycosylphosphatidylinositol (GPI)-anchored glycoprotein on the cell surface. Previous studies have demonstrated contradictory roles for PrPC in connection with the phagocytic ability of macrophages. In the present work, we investigated the function of PrPC in phagocytosis and cytokine expression in bone marrow-derived macrophages infected with Escherichia coli. E. coli infection induced an increase in the PRNP mRNA level. Knockout of PrPC promoted bacterial uptake; upregulated Rab5, Rab7, and Eea1 mRNA expression; and increased the recruitment of lysosomal-associated membrane protein-2 to phagosomes, suggesting enhanced microbicidal activity. Remarkably, knockout of PrPC suppressed the proliferation of internalized bacteria and increased the expression of cytokines such as interleukin-1β. Collectively, our data reveal an important role of PrPC as a negative regulator for phagocytosis, phagosome maturation, cytokine expression, and macrophage microbicidal activity.
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Affiliation(s)
- Min Wang
- State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Deming Zhao
- State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Yang Yang
- State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Jin Liu
- State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Jin Wang
- State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Xiaomin Yin
- State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Lifeng Yang
- State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Xiangmei Zhou
- State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China
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19
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Arsenault RJ, Maattanen P, Daigle J, Potter A, Griebel P, Napper S. From mouth to macrophage: mechanisms of innate immune subversion by Mycobacterium avium subsp. paratuberculosis. Vet Res 2014; 45:54. [PMID: 24885748 PMCID: PMC4046017 DOI: 10.1186/1297-9716-45-54] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 03/31/2014] [Indexed: 11/10/2022] Open
Abstract
Johne’s disease (JD) is a chronic enteric infection of cattle caused by Mycobacterium avium subsp. paratuberculosis (MAP). The high economic cost and potential zoonotic threat of JD have driven efforts to develop tools and approaches to effectively manage this disease within livestock herds. Efforts to control JD through traditional animal management practices are complicated by MAP’s ability to cause long-term environmental contamination as well as difficulties associated with diagnosis of JD in the pre-clinical stages. As such, there is particular emphasis on the development of an effective vaccine. This is a daunting challenge, in large part due to MAP’s ability to subvert protective host immune responses. Accordingly, there is a priority to understand MAP’s interaction with the bovine host: this may inform rational targets and approaches for therapeutic intervention. Here we review the early host defenses encountered by MAP and the strategies employed by the pathogen to avert or subvert these responses, during the critical period between ingestion and the establishment of persistent infection in macrophages.
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Affiliation(s)
| | | | | | | | | | - Scott Napper
- VIDO-InterVac, University of Saskatchewan, Saskatoon, SK S7N 5E3, Canada.
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20
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Fischer N, Mak TN, Shinohara DB, Sfanos KS, Meyer TF, Brüggemann H. Deciphering the intracellular fate of Propionibacterium acnes in macrophages. BIOMED RESEARCH INTERNATIONAL 2013; 2013:603046. [PMID: 23862148 PMCID: PMC3687600 DOI: 10.1155/2013/603046] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 05/07/2013] [Accepted: 05/22/2013] [Indexed: 01/19/2023]
Abstract
Propionibacterium acnes is a Gram-positive bacterium that colonizes various niches of the human body, particularly the sebaceous follicles of the skin. Over the last years a role of this common skin bacterium as an opportunistic pathogen has been explored. Persistence of P. acnes in host tissue has been associated with chronic inflammation and disease development, for example, in prostate pathologies. This study investigated the intracellular fate of P. acnes in macrophages after phagocytosis. In a mouse model of P. acnes-induced chronic prostatic inflammation, the bacterium could be detected in prostate-infiltrating macrophages at 2 weeks postinfection. Further studies performed in the human macrophage cell line THP-1 revealed intracellular survival and persistence of P. acnes but no intracellular replication or escape from the host cell. Confocal analyses of phagosome acidification and maturation were performed. Acidification of P. acnes-containing phagosomes was observed at 6 h postinfection but then lost again, indicative of cytosolic escape of P. acnes or intraphagosomal pH neutralization. No colocalization with the lysosomal markers LAMP1 and cathepsin D was observed, implying that the P. acnes-containing phagosome does not fuse with lysosomes. Our findings give first insights into the intracellular fate of P. acnes; its persistency is likely to be important for the development of P. acnes-associated inflammatory diseases.
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Affiliation(s)
- Natalie Fischer
- Unit Molecular Microbial Pathogenesis, Pasteur Institute, 75724 Paris, France
- Department of Molecular Biology, Max Planck Institute for Infection Biology, 10117 Berlin, Germany
| | - Tim N. Mak
- Department of Molecular Biology, Max Planck Institute for Infection Biology, 10117 Berlin, Germany
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 4, Bartholin Building, 8000 Aarhus C, Denmark
| | - Debika Biswal Shinohara
- Department of Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21231, USA
| | - Karen S. Sfanos
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Thomas F. Meyer
- Department of Molecular Biology, Max Planck Institute for Infection Biology, 10117 Berlin, Germany
| | - Holger Brüggemann
- Department of Molecular Biology, Max Planck Institute for Infection Biology, 10117 Berlin, Germany
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 4, Bartholin Building, 8000 Aarhus C, Denmark
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21
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Haka AS, Grosheva I, Singh RK, Maxfield FR. Plasmin promotes foam cell formation by increasing macrophage catabolism of aggregated low-density lipoprotein. Arterioscler Thromb Vasc Biol 2013; 33:1768-78. [PMID: 23702659 DOI: 10.1161/atvbaha.112.301109] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The plasmin/plasminogen system is involved in atherosclerosis. However, the mechanisms by which it stimulates disease are not fully defined. A key event in atherogenesis is the deposition of low-density lipoprotein (LDL) on arterial walls where it is modified, aggregated, and retained. Macrophages are recruited to clear the lipoproteins, and they become foam cells. The goal of this study was to assess the role of plasmin in macrophage uptake of aggregated LDL and foam cell formation. APPROACH AND RESULTS Plasminogen treatment of macrophages catabolizing aggregated LDL significantly accelerated foam cell formation. Macrophage interaction with aggregated LDL increased the surface expression of urokinase-type plasminogen activator receptor and plasminogen activator activity, resulting in increased ability to generate plasmin at the cell surface. The high local level of plasmin cleaves cell-associated aggregated LDL, allowing a portion of the aggregate to become sequestered in a nearly sealed, yet extracellular, acidic compartment. The low pH in the plasmin-induced compartment allows lysosomal enzymes, delivered via lysosome exocytosis, greater activity, resulting in more efficient cholesteryl ester hydrolysis and delivery of a large cholesterol load to the macrophage, thereby promoting foam cell formation. CONCLUSIONS These findings highlight a critical role for plasmin in the catabolism of aggregated LDL by macrophages and provide a new context for considering the atherogenic role of plasmin.
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Affiliation(s)
- Abigail S Haka
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
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22
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Sokolovska A, Becker CE, Ip WKE, Rathinam VAK, Brudner M, Paquette N, Tanne A, Vanaja SK, Moore KJ, Fitzgerald KA, Lacy-Hulbert A, Stuart LM. Activation of caspase-1 by the NLRP3 inflammasome regulates the NADPH oxidase NOX2 to control phagosome function. Nat Immunol 2013; 14:543-53. [PMID: 23644505 PMCID: PMC3708594 DOI: 10.1038/ni.2595] [Citation(s) in RCA: 158] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 03/28/2013] [Indexed: 11/10/2022]
Abstract
Phagocytosis is a fundamental cellular process that is pivotal for immunity as it coordinates microbial killing, innate immune activation and antigen presentation. An essential step in this process is phagosome acidification, which regulates many functions of these organelles that allow phagosomes to participate in processes that are essential to both innate and adaptive immunity. Here we report that acidification of phagosomes containing Gram-positive bacteria is regulated by the NLRP3 inflammasome and caspase-1. Active caspase-1 accumulates on phagosomes and acts locally to control the pH by modulating buffering by the NADPH oxidase NOX2. These data provide insight into a mechanism by which innate immune signals can modify cellular defenses and establish a new function for the NLRP3 inflammasome and caspase-1 in host defense.
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Affiliation(s)
- Anna Sokolovska
- Developmental Immunology and Center for Computational and Integrative Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA.
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23
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Abstract
Phagocytosis and phagosome maturation are crucial processes in biology. Phagocytosis and the subsequent digestion of phagocytosed particles occur across a huge diversity of eukaryotes and can be achieved by many different cells within one organism. In parallel, diverse groups of pathogens have evolved mechanisms to avoid killing by phagocytic cells. The present review discusses a key innate immune cell, the macrophage, and highlights the myriad mechanisms microbes have established to escape phagocytic killing.
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Affiliation(s)
- Leanne M Smith
- Institute of Microbiology and Infection, School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K
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24
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Schmerk CL, Valvano MA. Burkholderia multivorans survival and trafficking within macrophages. J Med Microbiol 2013; 62:173-184. [PMID: 23105020 DOI: 10.1099/jmm.0.051243-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023] Open
Abstract
Cystic fibrosis (CF) patients are at great risk of opportunistic lung infection, particularly by members of the Burkholderia cepacia complex (Bcc). This group of bacteria can cause damage to the lung tissue of infected patients and are difficult to eradicate due to their high levels of antibiotic resistance. Although the highly virulent Burkholderia cenocepacia has been the focus of virulence research for the past decade, Burkholderia multivorans is emerging as the most prevalent Bcc species infecting CF patients in North America. Despite several studies detailing the intramacrophage trafficking and survival of B. cenocepacia, no such data exist for B. multivorans. The results of this study demonstrated that the clinical CF isolates C5568 and C0514 and an environmental B. multivorans isolate, ATCC 17616, were able to replicate and survive within murine macrophages in a manner similar to that of B. cenocepacia strain K56-2. These strains were also able to survive but were unable to replicate within human THP-1 macrophages. Differences in macrophage uptake were observed among all three B. multivorans strains; these variances were attributed to major differences in O-antigen production. Unlike B. cenocepacia-containing vacuoles, which delay phagosomal maturation in murine macrophages by 6 h, all B. multivorans-containing vacuoles co-localized with lysosome-associated membrane protein-1, a late endosome/lysosomal marker, and the lysosomal marker dextran within 2 h of uptake. Together, these results indicated that, whilst both Bcc species were able to survive and replicate within macrophages, they utilized different intramacrophage survival strategies. To observe differences in virulence, the strains were compared using the Galleria mellonella (wax worm) model. When compared with the B. multivorans strains tested, B. cenocepacia K56-2 was highly virulent in this model and killed all worms within 24 h when injected at 10(7) c.f.u. B. multivorans clinical isolates C5568 and C0514 were significantly more virulent than the soil isolate ATCC 17616, which was avirulent even when worms were injected with 10(7) c.f.u. These results suggest strain differences in the virulence of B. multivorans isolates.
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Affiliation(s)
- Crystal L Schmerk
- Center for Human Immunology, University of Western Ontario, London, Ontario, N6A 5C1, Canada
- Microbiology and Immunology, University of Western Ontario, London, Ontario, N6A 5C1, Canada
| | - Miguel A Valvano
- Center for Human Immunology, University of Western Ontario, London, Ontario, N6A 5C1, Canada
- Microbiology and Immunology, University of Western Ontario, London, Ontario, N6A 5C1, Canada
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25
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Arango Duque G, Fukuda M, Descoteaux A. Synaptotagmin XI regulates phagocytosis and cytokine secretion in macrophages. THE JOURNAL OF IMMUNOLOGY 2013; 190:1737-45. [PMID: 23303671 DOI: 10.4049/jimmunol.1202500] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Synaptotagmins (Syts) are a group of type I membrane proteins that regulate vesicle docking and fusion in processes such as exocytosis and phagocytosis. All Syts possess a single transmembrane domain, and two conserved tandem Ca(2+)-binding C2 domains. However, Syts IV and XI possess a conserved serine in their C2A domain that precludes these Syts from binding Ca(2+) and phospholipids, and from mediating vesicle fusion. Given the importance of vesicular trafficking in macrophages, we investigated the role of Syt XI in cytokine secretion and phagocytosis. We demonstrated that Syt XI is expressed in murine macrophages, localized in recycling endosomes, lysosomes, and recruited to phagosomes. Syt XI had a direct effect on phagocytosis and on the secretion of TNF and IL-6. Whereas small interfering RNA-mediated knockdown of Syt XI potentiated secretion of these cytokines and particle uptake, overexpression of an Syt XI construct suppressed these processes. In addition, Syt XI knockdown led to decreased recruitment of gp91(phox) and lysosomal-associated membrane protein-1 to phagosomes, suggesting attenuated microbicidal activity. Remarkably, knockdown of Syt XI ensued in enhanced bacterial survival. Our data reveal a novel role for Syt XI as a regulator of cytokine secretion, particle uptake, and macrophage microbicidal activity.
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Affiliation(s)
- Guillermo Arango Duque
- Institut National de la Recherche Scientifique-Institut Armand-Frappier, Laval, Quebec H7V 1B7, Canada
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26
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Steinhäuser C, Heigl U, Tchikov V, Schwarz J, Gutsmann T, Seeger K, Brandenburg J, Fritsch J, Schroeder J, Wiesmüller KH, Rosenkrands I, Walther P, Pott J, Krause E, Ehlers S, Schneider-Brachert W, Schütze S, Reiling N. Lipid-labeling facilitates a novel magnetic isolation procedure to characterize pathogen-containing phagosomes. Traffic 2012; 14:321-36. [PMID: 23231467 DOI: 10.1111/tra.12031] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Revised: 11/28/2012] [Accepted: 12/11/2012] [Indexed: 02/03/2023]
Abstract
Here we describe a novel approach for the isolation and biochemical characterization of pathogen-containing compartments from primary cells: We developed a lipid-based procedure to magnetically label the surface of bacteria and visualized the label by scanning and transmission electron microscopy (SEM, TEM). We performed infection experiments with magnetically labeled Mycobacterium avium, M. tuberculosis and Listeria monocytogenes and isolated magnetic bacteria-containing phagosomes using a strong magnetic field in a novel free-flow system. Magnetic labeling of M. tuberculosis did not affect the virulence characteristics of the bacteria during infection experiments addressing host cell activation, phagosome maturation delay and replication in macrophages in vitro. Biochemical analyses of the magnetic phagosome-containing fractions provided evidence of an enhanced presence of bacterial antigens and a differential distribution of proteins involved in the endocytic pathway over time as well as cytokine-dependent changes in the phagosomal protein composition. The newly developed method represents a useful approach to characterize and compare pathogen-containing compartments, in order to identify microbial and host cell targets for novel anti-infective strategies.
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Affiliation(s)
- Christine Steinhäuser
- Division of Microbial Interface Biology, Research Center Borstel, Leibniz Center for Medicine and Biosciences, Borstel, 23845, Germany
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27
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Xu L, Luo ZQ. Cell biology of infection by Legionella pneumophila. Microbes Infect 2012; 15:157-67. [PMID: 23159466 DOI: 10.1016/j.micinf.2012.11.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 11/02/2012] [Accepted: 11/05/2012] [Indexed: 01/09/2023]
Abstract
Professional phagocytes digest internalized microorganisms by actively delivering them into the phagolysosomal compartment. Intravacuolar bacterial pathogens have evolved a variety of effective strategies to bypass the default pathway of phagosomal maturation to create a niche permissive for their survival and propagation. Here we discuss recent progress in our understanding of the sophisticated mechanisms used by Legionella pneumophila to survive in phagocytes.
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Affiliation(s)
- Li Xu
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, United States
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28
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Coutinho-Silva R, Ojcius DM. Role of extracellular nucleotides in the immune response against intracellular bacteria and protozoan parasites. Microbes Infect 2012; 14:1271-7. [PMID: 22634346 DOI: 10.1016/j.micinf.2012.05.009] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Revised: 04/29/2012] [Accepted: 05/14/2012] [Indexed: 02/06/2023]
Abstract
Extracellular nucleotides are danger signals involved in recognition and control of intracellular pathogens. They are an important component of the innate immune response against intracellular pathogens, inducing the recruitment of inflammatory cells, stimulating secretion of cytokines, and producing inflammatory mediators such as reactive oxygen species (ROS) and nitric oxide (NO). In the case of extracellular ATP, some of the immune responses are mediated through activation of the NLRP3 inflammasome and secretion of the cytokine, interleukin-1β (IL-1β), through a mechanism dependent on ligation of the P2X7 receptor. Here we review the role of extracellular nucleotides as sensors of intracellular bacteria and protozoan parasites, and discuss how these pathogens manipulate purinergic signaling to diminish the immune response against infection.
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Affiliation(s)
- Robson Coutinho-Silva
- Biophysics Institute Carlos Chagas Filho, Federal University of Rio de Janeiro, RJ 21941-902, Brazil.
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29
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Hung SL, Chiang HH, Wu CY, Hsu MJ, Chen YT. Effects of herpes simplex virus type 1 infection on immune functions of human neutrophils. J Periodontal Res 2012; 47:635-44. [PMID: 22471246 DOI: 10.1111/j.1600-0765.2012.01476.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND AND OBJECTIVE Herpesviruses may play roles in the development of periodontal diseases. This study analyzed the effects of herpes simplex virus type 1 (HSV-1) infection on neutrophil function. The effects of lipopolysaccharide (LPS) from the periodontal pathogen, Porphyromonas gingivalis, during HSV-1 infection were also determined. MATERIAL AND METHODS Purified HSV-1 was pretreated with buffer containing no serum, with HSV-1 immunoglobulin G (IgG)-positive serum (HSV-1 antiserum) or with control serum. Neutrophils were mock-infected or infected with the pretreated HSV-1. Viral binding and phagosome formation were detected using immunostaining. Intracellular reactive oxygen species (ROS) were determined using 2',7'-dichlorofluorescin diacetate and fluorometry. Leukotriene B(4) (LTB(4)) and interleukin-8 (IL-8) were detected using enzyme immunoassays. Release of matrix metalloproteinase-9 (MMP-9) was examined using gelatin zymography. Phosphorylation of Akt/glycogen synthase kinase-3 (GSK-3) was determined using western blotting. RESULTS HSV-1 bound directly to neutrophils and enhanced the release of MMP-9. HSV-1 immune complexes, formed in the HSV-1 antiserum, bound neutrophils and induced the formation of early phagosome more effectively than did HSV-1 alone. The relative levels of ROS and phosphorylation of Akt/GSK-3 were increased significantly in neutrophils after infection with HSV-1 immune complexes. Infection with HSV-1 and HSV-1 immune complexes also stimulated the production of inflammatory mediators, LTB(4) and IL-8. Moreover, LPS enhanced the HSV-1-stimulatory production of IL-8. CONCLUSION This study demonstrated differences in neutrophils infected with HSV-1 alone or with HSV-1 immune complexes, suggesting that opsonization of HSV-1 might enhance its effects on neutrophils. The in vitro findings suggest that HSV-1 infection may induce the inflammatory response and affect periodontal health.
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Affiliation(s)
- S-L Hung
- Institute of Oral Biology, National Yang-Ming University, Taipei, Taiwan
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30
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The Coxiella burnetii parasitophorous vacuole. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 984:141-69. [PMID: 22711631 DOI: 10.1007/978-94-007-4315-1_8] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Coxiella burnetii is a bacterial intracellular parasite of eucaryotic cells that replicates within a membrane-bound compartment, or "parasitophorous vacuole" (PV). With the exception of human macrophages/monocytes, the consensus model of PV trafficking in host cells invokes endolysosomal maturation culminating in lysosome fusion. C. burnetii resists the degradative functions of the vacuole while at the same time exploiting the acidic pH for metabolic activation. While at first glance the mature PV resembles a large phagolysosome, an increasing body of evidence indicates the vacuole is in fact a specialized compartment that is actively modified by the pathogen. Adding to the complexity of PV biogenesis is new data showing vacuole engagement with autophagic and early secretory pathways. In this chapter, we review current knowledge of PV nature and development, and discuss disparate data related to the ultimate maturation state of PV harboring virulent or avirulent C. burnetii lipopolysaccharide phase variants in human mononuclear phagocytes.
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31
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Serda RE, Mack A, van de Ven AL, Ferrati S, Dunner K, Godin B, Chiappini C, Landry M, Brousseau L, Liu X, Bean AJ, Ferrari M. Logic-embedded vectors for intracellular partitioning, endosomal escape, and exocytosis of nanoparticles. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2010; 6:2691-700. [PMID: 20957619 PMCID: PMC2997879 DOI: 10.1002/smll.201000727] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Revised: 07/22/2010] [Indexed: 05/08/2023]
Abstract
A new generation of nanocarriers, logic-embedded vectors (LEVs), is endowed with the ability to localize components at multiple intracellular sites, thus creating an opportunity for synergistic control of redundant or dual-hit pathways. LEV encoding elements include size, shape, charge, and surface chemistry. In this study, LEVs consist of porous silicon nanocarriers, programmed for cellular uptake and trafficking along the endosomal pathway, and surface-tailored iron oxide nanoparticles, programmed for endosomal sorting and partitioning of particles into unique cellular locations. In the presence of persistent endosomal localization of silicon nanocarriers, amine-functionalized nanoparticles are sorted into multiple vesicular bodies that form novel membrane-bound compartments compatible with cellular secretion, while chitosan-coated nanoparticles escape from endosomes and enter the cytosol. Encapsulation within the porous silicon matrix protects these nanoparticle surface-tailored properties, and enhances endosomal escape of chitosan-coated nanoparticles. Thus, LEVs provide a mechanism for shielded transport of nanoparticles to the lesion, cellular manipulation at multiple levels, and a means for targeting both within and between cells.
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Affiliation(s)
- Rita E Serda
- Department of NanoMedicine and Biomedical Engineering, University of Texas Health Science Center, 1825 Pressler Street, Suite 537, Houston, TX 77030, USA.
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32
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VanderVen BC, Hermetter A, Huang A, Maxfield FR, Russell DG, Yates RM. Development of a novel, cell-based chemical screen to identify inhibitors of intraphagosomal lipolysis in macrophages. Cytometry A 2010; 77:751-60. [PMID: 20653015 DOI: 10.1002/cyto.a.20911] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Macrophages play a central role in tissue homeostasis and the immune system. Their primary function is to internalize cellular debris and microorganisms for degradation within their phagosomes. In this context, their capacity to process and sequester lipids such as triacylglycerides and cholesteryl esters makes them key players in circulatory diseases, such as atheroclerosis. To discover new inhibitors of lipolytic processing within the phagosomal system of the macrophage, we have developed a novel, cell-based assay suitable for high-throughput screening. We employed particles carrying a fluorogenic triglyceride substrate and a calibration fluor to screen for inhibitors of phagosomal lipolysis. A panel of secondary assays were employed to discriminate between lipase inhibitors and compounds that perturbed general phagosomal trafficking events. This process enabled us to identify a new structural class of pyrazole-methanone compounds that directly inhibit lysosomal and lipoprotein lipase activity.
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Affiliation(s)
- Brian C VanderVen
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA
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Caberoy NB, Zhou Y, Li W. Tubby and tubby-like protein 1 are new MerTK ligands for phagocytosis. EMBO J 2010; 29:3898-910. [PMID: 20978472 DOI: 10.1038/emboj.2010.265] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Accepted: 09/27/2010] [Indexed: 12/29/2022] Open
Abstract
Tubby and tubby-like protein 1 (Tulp1) are newly identified phagocytosis ligands to facilitate retinal pigment epithelium (RPE) and macrophage phagocytosis. Both proteins without classical signal peptide have been demonstrated with unconventional secretion. Here, we characterized them as novel MerTK ligands to facilitate phagocytosis. Tulp1 interacts with Tyro3, Axl and MerTK of the TAM receptor tyrosine kinase subfamily, whereas tubby binds only to MerTK. Excessive soluble MerTK extracellular domain blocked tubby- or Tulp1-mediated phagocytosis. Both ligands induced MerTK activation with receptor phosphorylation and signalling cascade, including non-muscle myosin II redistribution and co-localization with phagosomes. Tubby and Tulp1 are bridging molecules with their N-terminal region as MerTK-binding domain and C-terminal region as phagocytosis prey-binding domain (PPBD). Five minimal phagocytic determinants (MPDs) of K/R(X)(1-2)KKK in Tulp1 N-terminus were defined as essential motifs for MerTK binding, receptor phosphorylation and phagocytosis. PPBD was mapped to the highly conserved 54 amino acids at the C-terminal end of tubby and Tulp1. These data suggest that tubby and Tulp1 are novel bridging molecules to facilitate phagocytosis through MerTK.
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Affiliation(s)
- Nora B Caberoy
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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Ouellette SP, Carabeo RA. A Functional Slow Recycling Pathway of Transferrin is Required for Growth of Chlamydia. Front Microbiol 2010; 1:112. [PMID: 21607082 PMCID: PMC3095398 DOI: 10.3389/fmicb.2010.00112] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Accepted: 09/10/2010] [Indexed: 01/11/2023] Open
Abstract
An inhibitor of host cell lysophospholipid acyltransferase, an enzyme involved in lipid metabolism blocked growth of the obligate intracellular pathogen Chlamydia through its action on the transport of transferrin (Tf) via the slow pathway of recycling. A detailed characterization of this inhibition revealed that Tf accumulated in vesicles positive for Rab11, with a concomitant reduction in the level of Tf found within the transport intermediate Rab4/11 hybrid vesicles. The net result was the failure to be recycled to the plasma membrane. In chlamydiae-infected cells, the Tf-containing Rab11-positive vesicles were typically found intimately associated with the inclusion, and treatment with the inhibitor caused their accumulation, suggesting that the timely progression and completion of Tf recycling was necessary for proper chlamydial growth. Growth inhibition by the compound could be negated by the simple removal of the Tf-containing fraction of the serum, a further indication that accumulation of Tf around the chlamydial inclusion was deleterious to the pathogen. Thus, it appears that manipulating the slow recycling pathway can have biological consequences for Chlamydia and implies the need to regulate carefully the interaction of the inclusion with this host trafficking pathway.
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Affiliation(s)
- Scot P Ouellette
- Centre for Molecular Microbiology and Infection, Division of Cell and Molecular Biology, Imperial College London London, UK
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35
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O'Leary S, O'Sullivan MP, Keane J. IL-10 blocks phagosome maturation in mycobacterium tuberculosis-infected human macrophages. Am J Respir Cell Mol Biol 2010; 45:172-80. [PMID: 20889800 DOI: 10.1165/rcmb.2010-0319oc] [Citation(s) in RCA: 184] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Successful phagolysosomal maturation is an important innate immune response to intracellular infection. However, Mycobacterium tuberculosis (Mtb) can manipulate and inhibit this host response to ensure survival within its niche cell. We investigate the role of the anti-inflammatory cytokine IL-10 on Mtb-phagosome maturation. Blocking IL-10, which was secreted from Mtb-infected macrophages, allowed phagosome maturation to proceed. Macrophage cytokine gene expression profiles were not significantly altered by blocking IL-10 3 hours after infection with Mtb. We demonstrate that IL-10 can regulate this protective phenotype in phorbol myristate acetate (PMA)-treated THP-1 cells, monocyte-derived macrophages (MDMs), and human alveolar macrophages (AMs) infected with Mtb. The regulatory effect of endogenous IL-10 was evident in macrophages infected with virulent Mtb H37Rv, as well as in attenuated strains of mycobacteria. Unlike live Mtb, dead bacilli occupy a mature, acidic phagosome. However, the addition of IL-10 to cells infected with killed Mtb successfully inhibited the maturation of this compartment. Importantly, we demonstrate that the addition of IL-10 to MDMs results in enhanced mycobacterial survival and growth. Our results suggest that IL-10 exerts its effects on this early macrophage response in a partly signal transducer and activator of transcription 3 (STAT3)-dependent manner, and independent of mitogen activated protein kinase p38 (MAPKp38) and extracellular regulated kinase 1/2 (ERK1/2) activity. IL-10 is a feature of human tuberculous granuloma, and these new findings support the hypothesis that this cytokine can promote pathogen persistence by contributing to Mtb-phagosome maturation arrest in human macrophages.
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Affiliation(s)
- Seónadh O'Leary
- Respiratory Medicine, St. James's Hospital, CResT, Dublin 8, Ireland
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36
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Davis MJ, Swanson JA. Technical advance: Caspase-1 activation and IL-1β release correlate with the degree of lysosome damage, as illustrated by a novel imaging method to quantify phagolysosome damage. J Leukoc Biol 2010; 88:813-22. [PMID: 20587739 PMCID: PMC2974426 DOI: 10.1189/jlb.0310159] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Revised: 05/21/2010] [Accepted: 06/05/2010] [Indexed: 11/24/2022] Open
Abstract
In addition to the lysosome's important roles in digestion, antigen processing, and microbial destruction, lysosome damage in macrophages can trigger cell death and release of the inflammatory cytokine IL-1β. To examine the relationship among endocytosis, lysosome damage, and subsequent events, such as caspase-1 activation and IL-1β secretion, we developed a method for measuring lysosome disruption inside individual living cells, which quantifies release of Fdx from lysosomes. Unperturbed, cultured BMM exhibited low levels of lysosome damage, which were not increased by stimulation of macropinocytosis. Lysosome damage following phagocytosis differed with different types of ingested particles, with negligible damage after ingestion of sRBC ghosts, intermediate damage by polystyrene (PS) beads, and high levels of damage by ground silica. Pretreatment with LPS decreased the amount of lysosome damage following phagocytosis of PS beads, silica microspheres, or ground silica. Activation of caspase-1 and subsequent release of IL-1β were proportional to lysosome damage following phagocytosis. The low level of damage following PS bead phagocytosis was insufficient to activate caspase-1 in LPS-activated macrophages. These studies indicate that lysosome damage following phagocytosis is dependent on particle composition and dose and that caspase-1 activation and IL-1β secretion correlate with the extent of lysosome damage.
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Affiliation(s)
| | - Joel A. Swanson
- Program in Immunology and
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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37
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Feng D, Zhao WL, Ye YY, Bai XC, Liu RQ, Chang LF, Zhou Q, Sui SF. Cellular internalization of exosomes occurs through phagocytosis. Traffic 2010; 11:675-87. [PMID: 20136776 DOI: 10.1111/j.1600-0854.2010.01041.x] [Citation(s) in RCA: 697] [Impact Index Per Article: 49.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Exosomes play important roles in many physiological and pathological processes. However, the exosome-cell interaction mode and the intracellular trafficking pathway of exosomes in their recipient cells remain unclear. Here, we report that exosomes derived from K562 or MT4 cells are internalized more efficiently by phagocytes than by non-phagocytic cells. Most exosomes were observed attached to the plasma membrane of non-phagocytic cells, while in phagocytic cells these exosomes were found to enter via phagocytosis. Specifically, they moved to phagosomes together with phagocytic polystyrene carboxylate-modified latex beads (biospheres) and were further sorted into phagolysosomes. Moreover, exosome internalization was dependent on the actin cytoskeleton and phosphatidylinositol 3-kinase, and could be inhibited by the knockdown of dynamin2 or overexpression of a dominant-negative form of dynamin2. Further, antibody pretreatment assays demonstrated that tim4 but not tim1 was involved in exosomes uptake. We also found that exosomes did not enter the internalization pathway involving caveolae, macropinocytosis and clathrin-coated vesicles. Our observation that the cellular uptake of exosomes occurs through phagocytosis has important implications for exosome-cell interactions and the exosome intracellular trafficking pathway.
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Affiliation(s)
- Du Feng
- School of Life Sciences, State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua University, Beijing, PR China
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38
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Coxiella burnetii phase I and II variants replicate with similar kinetics in degradative phagolysosome-like compartments of human macrophages. Infect Immun 2010; 78:3465-74. [PMID: 20515926 DOI: 10.1128/iai.00406-10] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Coxiella burnetii infects mononuclear phagocytes, where it directs biogenesis of a vacuolar niche termed the parasitophorous vacuole (PV). Owing to its lumenal pH (approximately 5) and fusion with endolysosomal vesicles, the PV is considered phagolysosome-like. However, the degradative properties of the mature PV are unknown, and there are conflicting reports on the maturation state and growth permissiveness of PV harboring virulent phase I or avirulent phase II C. burnetii variants in human mononuclear phagocytes. Here, we employed infection of primary human monocyte-derived macrophages (HMDMs) and THP-1 cells as host cells to directly compare the PV maturation kinetics and pathogen growth in cells infected with the Nine Mile phase I variant (NMI) or phase II variant (NMII) of C. burnetii. In both cell types, phase variants replicated with similar kinetics, achieving roughly 2 to 3 log units of growth before they reached stationary phase. HMDMs infected by either phase variant secreted similar amounts of the proinflammatory cytokines interleukin-6 and tumor necrosis factor alpha. In infected THP-1 cells, equal percentages of NMI and NMII PVs decorate with the early endosomal marker Rab5, the late endosomal/lysosomal markers Rab7 and CD63, and the lysosomal marker cathepsin D at early (8 h) and late (72 h) time points postinfection (p.i.). Mature PVs (2 to 4 days p.i.) harboring NMI or NMII contained proteolytically active cathepsins and quickly degraded Escherichia coli. These data suggest that C. burnetii does not actively inhibit phagolysosome function as a survival mechanism. Instead, NMI and NMII resist degradation to replicate in indistinguishable digestive PVs that fully mature through the endolysosomal pathway.
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Parashuraman S, Madan R, Mukhopadhyay A. NSF independent fusion of Salmonella-containing late phagosomes with early endosomes. FEBS Lett 2010; 584:1251-6. [PMID: 20176016 DOI: 10.1016/j.febslet.2010.02.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 02/04/2010] [Accepted: 02/16/2010] [Indexed: 11/27/2022]
Abstract
Initial characterizations of live-Salmonella-containing early (LSEP) and late phagosomes (LSLP) in macrophages show that both phagosomes retain Rab5 and EEA1. In addition, LSEP specifically contain transferrin receptor whereas LSLP possess relatively more rabaptin-5. In contrast to LSLP, late-Salmonella-containing vacuoles in epithelial cells show significantly reduced levels of Rab5 and EEA1. Subsequent results demonstrate that both phagosomes efficiently fuse with early endosomes (EE). In contrast to LSEP, fusion between LSLP and EE is insensitive to ATPgammaS treatment. Furthermore, LSLP fuses with EE in absence of NEM-sensitive fusion factor (NSF) as well as in the presence of NSF:D1EQ mutant demonstrating that LSLP fusion with EE is NSF independent.
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40
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Chamekh M. Immunomodulation using genetically engineered bacteria for type III-mediated delivery of heterologous antigens and cytokines: Potential application in vaccine and therapeutical developments. Immunopharmacol Immunotoxicol 2010. [DOI: 10.3109/08923970902817890] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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41
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Amer AO. Modulation of caspases and their non-apoptotic functions byLegionella pneumophila. Cell Microbiol 2010; 12:140-7. [DOI: 10.1111/j.1462-5822.2009.01401.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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42
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Le Foll F, Rioult D, Boussa S, Pasquier J, Dagher Z, Leboulenger F. Characterisation of Mytilus edulis hemocyte subpopulations by single cell time-lapse motility imaging. FISH & SHELLFISH IMMUNOLOGY 2010; 28:372-386. [PMID: 19944763 DOI: 10.1016/j.fsi.2009.11.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2009] [Revised: 10/28/2009] [Accepted: 11/14/2009] [Indexed: 05/28/2023]
Abstract
In bivalve molluscs, defence against pathogens mainly relies on fast tissue infiltration by immunocompetent hemocytes that migrate from circulating hemolymph to sites of infection, in order to deliver, in situ, an effective immune response. In the present work, we have investigated dynamics of hemocyte subpopulations motility by combining flow cytometry coupled to Coulter-type cell volume determination, Hoffman modulation contrast microscopy, time-lapse imaging and off-line analysis of cell shape changes. Our results revealed fast modifications of hemocyte aspect in vitro, with bidirectional transitions from spread outlines to condensed cell body morphologies, in the minute range. Amoeboid or non-amoeboid types of locomotion were observed, depending on the cell shapes and on the cell subtypes, with velocities reaching up to 30 mum min(-1). Correlations between motion profiles, Hemacolor staining and flow cytometry analysis on living cells help to propose a functional mussel hemocyte classification including the motile properties of these cells. In particular, basophils were shown to be involved in dynamic hemocyte-hemocyte interactions and in the constitution of aggregation cores. Physiological implications, in terms of immune response in organisms devoid of endothelium-closed vascular system, and potential applications of hemocyte motility studies for the development and the interpretation of experiments involving hemocytes in the field of marine ecotoxicology are discussed.
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Affiliation(s)
- Frank Le Foll
- Laboratory of Ecotoxicology, University of Le Havre, EA 3222, IFRMP 23, BP 540, 76058 Le Havre cedex, France.
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43
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Raman K, Bhat AG, Chandra N. A systems perspective of host-pathogen interactions: predicting disease outcome in tuberculosis. MOLECULAR BIOSYSTEMS 2009; 6:516-30. [PMID: 20174680 DOI: 10.1039/b912129c] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The complex web of interactions between the host immune system and the pathogen determines the outcome of any infection. A computational model of this interaction network, which encodes complex interplay among host and bacterial components, forms a useful basis for improving the understanding of pathogenesis, in filling knowledge gaps and consequently to identify strategies to counter the disease. We have built an extensive model of the Mycobacterium tuberculosis host-pathogen interactome, consisting of 75 nodes corresponding to host and pathogen molecules, cells, cellular states or processes. Vaccination effects, clearance efficiencies due to drugs and growth rates have also been encoded in the model. The system is modelled as a Boolean network. Virtual deletion experiments, multiple parameter scans and analysis of the system's response to perturbations, indicate that disabling processes such as phagocytosis and phagolysosome fusion or cytokines such as TNF-alpha and IFN-gamma, greatly impaired bacterial clearance, while removing cytokines such as IL-10 alongside bacterial defence proteins such as SapM greatly favour clearance. Simulations indicate a high propensity of the pathogen to persist under different conditions.
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Affiliation(s)
- Karthik Raman
- Bioinformatics Centre, Indian Institute of Science, Bangalore - 560012, India.
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44
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He B, Lu N, Zhou Z. Cellular and nuclear degradation during apoptosis. Curr Opin Cell Biol 2009; 21:900-12. [PMID: 19781927 PMCID: PMC2787732 DOI: 10.1016/j.ceb.2009.08.008] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Revised: 08/27/2009] [Accepted: 08/28/2009] [Indexed: 11/27/2022]
Abstract
Apoptosis ensures quick death and quiet clearance of unwanted or damaged cells, without inducing much, if any, immunological responses from the organism. In metazoan organisms, apoptotic cells are swiftly engulfed by other cells. The degradation of cellular content is initiated in apoptotic cells and completed within engulfing cells. In apoptotic cells, caspase-mediated proteolysis cleaves protein substrates into fragments; nuclear DNA is partially degraded into nucleosomal units; and autophagy potentially contributes to apoptotic cell removal. In engulfing cells, specific signaling pathways promote the sequential fusion of intracellular vesicles with phagosomes and lead to the complete degradation of apoptotic cells in an acidic environment. Phagocytic receptors that initiate the engulfment of apoptotic cells play an additional and crucial role in initiating phagosome maturation through activating these signaling pathways. Here we highlight recent discoveries made in invertebrate models and mammalian systems, focusing on the molecular mechanisms that regulate the efficient degradation of apoptotic cells.
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Affiliation(s)
- Bin He
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Nan Lu
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zheng Zhou
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
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45
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CARD9 facilitates microbe-elicited production of reactive oxygen species by regulating the LyGDI-Rac1 complex. Nat Immunol 2009; 10:1208-14. [PMID: 19767757 DOI: 10.1038/ni.1788] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2009] [Accepted: 07/31/2009] [Indexed: 12/15/2022]
Abstract
In response to invading microorganisms, macrophages engage in phagocytosis and rapidly release reactive oxygen species (ROS), which serve an important microbicidal function. However, how phagocytosis induces ROS production remains largely unknown. CARD9, a caspase-recruitment domain (CARD)-containing protein, is important for resistance to fungal and bacterial infection. The mechanism of CARD9-mediated bacterial clearance is still mostly unknown. Here we show that CARD9 is required for killing intracellular bacteria in macrophages. CARD9 associated with the GDP-dissociation inhibitor LyGDI in phagosomes after bacterial and fungal infection and binding of CARD9 suppressed LyGDI-mediated inhibition of the GTPase Rac1, thereby leading to ROS production and bacterial killing in macrophages. Thus, our studies identify a key pathway that leads to microbe-elicited ROS production.
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46
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de Chastellier C, Forquet F, Gordon A, Thilo L. Mycobacterium requires an all-around closely apposing phagosome membrane to maintain the maturation block and this apposition is re-established when it rescues itself from phagolysosomes. Cell Microbiol 2009; 11:1190-207. [DOI: 10.1111/j.1462-5822.2009.01324.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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47
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Ghigo E, Pretat L, Desnues B, Capo C, Raoult D, Mege JL. Intracellular life of Coxiella burnetii in macrophages. Ann N Y Acad Sci 2009; 1166:55-66. [PMID: 19538264 DOI: 10.1111/j.1749-6632.2009.04515.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Coxiella burnetii, the agent of Q fever, is an obligate intracellular bacterium that is considered a potential biological weapon of category B. C. burnetii survives within myeloid cells by subverting receptor-mediated phagocytosis and preventing phagosome maturation. The intracellular fate of C. burnetii also depends on the functional state of myeloid cells. This review describes the mechanisms used by C. burnetii to circumvent uptake and trafficking events, and the role of cytokines on C. burnetii survival in myeloid cells.
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Affiliation(s)
- Eric Ghigo
- URMITE CNRS UMR 6236 - IRD 3R198, Institut Fédératif de Recherche 48, Université de la Méditerranée, Marseille, France.
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48
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Unfried K, Albrecht C, Klotz LO, Von Mikecz A, Grether-Beck S, Schins RP. Cellular responses to nanoparticles: Target structures and mechanisms. Nanotoxicology 2009. [DOI: 10.1080/00222930701314932] [Citation(s) in RCA: 249] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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49
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Chaves SP, Torres-Santos EC, Marques C, Figliuolo VR, Persechini PM, Coutinho-Silva R, Rossi-Bergmann B. Modulation of P2X(7) purinergic receptor in macrophages by Leishmania amazonensis and its role in parasite elimination. Microbes Infect 2009; 11:842-9. [PMID: 19439191 DOI: 10.1016/j.micinf.2009.05.001] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2008] [Revised: 04/13/2009] [Accepted: 05/02/2009] [Indexed: 12/20/2022]
Abstract
The purinergic P2X(7) receptor is a membrane protein of leucocytes involved in the clearance of intracellular bacteria such as Chlamydia and Mycobacterium. In this work, we investigated the role and modulation of macrophage P2X(7)R in intracellular infection with the protozoan parasite Leishmania amazonensis. Upon infection, isolated murine macrophages displayed enhanced expression of P2X(7)R and were significantly more responsive to extracellular ATP (ATPe)-induced pore opening, as demonstrated by the increased uptake of Lucifer Yellow. This was extended to the in vivo situation, where cells from established cutaneous lesions were more sensitive to ATPe than cells from uninfected mice. ATP treatment of infected macrophages inhibited parasite growth, and this was prevented by pre-treatment with oxidized ATP, a selective antagonist of P2X(7)R. Parasite killing was unlikely due to induction of nitric oxide production or cytolysis of infected macrophage, as those functions were unaltered with parasite-effective ATPe concentrations. A direct drug effect is also unlike, as ATPe enhanced axenic parasite growth. We found that leishmanial infection rendered wild-type but not P2X(7)R-deficient macrophages more prone to ATP-induced apoptosis. These results show that macrophage infection with L. amazonensis leads to enhanced expression of functional P2X(7)R, that upon ligation with ATPe helps in the elimination of the parasites by an as yet unclear mechanism possibly involving host cell apoptosis.
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Affiliation(s)
- Suzana Passos Chaves
- Laboratory of Immunopharmacology, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 373. 21941-902 Rio de Janeiro, Brazil
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50
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Balestrieri B, Maekawa A, Xing W, Gelb MH, Katz HR, Arm JP. Group V secretory phospholipase A2 modulates phagosome maturation and regulates the innate immune response against Candida albicans. THE JOURNAL OF IMMUNOLOGY 2009; 182:4891-8. [PMID: 19342668 DOI: 10.4049/jimmunol.0803776] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Phospholipase A(2) (PLA(2)) hydrolyzes the sn-2 position of cell membrane phospholipids to release fatty acids and lysophospholipids. We have previously reported that group V secretory PLA(2) (sPLA(2)) translocates from the Golgi and recycling endosomes of mouse peritoneal macrophages to newly formed phagosomes and regulates the phagocytosis of zymosan, suggesting a role in innate immunity. Here we report that in macrophages lacking group V sPLA(2), phagosome maturation was reduced 50-60% at early time points while the binding of zymosan was unimpaired. The ability of group V sPLA(2) to regulate phagocytosis extended to phagocytosis of IgG- and complement-opsonized sheep RBC. Moreover, macrophages lacking group V sPLA(2) had delays in phagocytosis, phagosome maturation, and killing of Candida albicans. Cytokine production and eicosanoid generation were not impaired by the lack of group V sPLA(2). Furthermore, in a model of systemic candidiasis, mice lacking group V sPLA(2) had an increased fungal burden in the kidney, liver, and spleen at day 7 postinfection and increased mortality. Thus, group V sPLA(2) regulates phagocytosis through major phagocytic receptors and contributes to the innate immune response against C. albicans by regulating phagocytosis and killing through a mechanism that is likely dependent on phagolysosome fusion.
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Affiliation(s)
- Barbara Balestrieri
- Department of Medicine, Harvard Medical School, Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA 02115, USA.
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