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Sang ZW, Bao MN, Liang Y, Chu KH, Wang L. Identification of acid phosphatase (ShACP) from the freshwater crab Sinopotamon henanense and its expression pattern changes in response to cadmium. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 255:114762. [PMID: 36931085 DOI: 10.1016/j.ecoenv.2023.114762] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 03/06/2023] [Accepted: 03/08/2023] [Indexed: 06/18/2023]
Abstract
Acid phosphatase(ACP) is an important immune enzyme in crustacean humoral immunity. At present, the research on ACP mainly focuses on the biochemical properties of the enzyme, while few studies on gene expression. In this study, ShACP was cloned and the effect of cadmium stress on the expression and function of ShACP in the freshwater crab Sinopotamon henanense was studied. Analysis of the ShACP sequence and tissue distribution results showed that the cDNA sequence of ShACP was 1629 bp, including 48 bp 5' untranslated region, 1209 bp open reading frame region, and 372 bp 3' untranslated region, encoding 402 amino acids. ShACP contained multiple phosphorylation sites and mainly played a role in the hemolymph. Under low-concentration cadmium stress, the body improved immunity by enhancing the expression of ShACP, while high-concentration cadmium stress inhibited the expression of ShACP. ShACP can promote the phagocytosis of hemocytes, while cadmium stress reduced the phagocytosis of hemocytes. This study provides a theoretical basis for further research on the immune system of crabs and is of great significance for the study of crustacean immune responses under heavy metal stress.
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Affiliation(s)
- Zhi-Wen Sang
- School of Life Science, Shanxi University, Taiyuan 030006, China
| | - Min-Nan Bao
- School of Life Science, Shanxi University, Taiyuan 030006, China
| | - Yue Liang
- School of Life Science, Shanxi University, Taiyuan 030006, China
| | - Ka-Hou Chu
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong
| | - Lan Wang
- School of Life Science, Shanxi University, Taiyuan 030006, China.
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2
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Kelley SM, Ravichandran KS. Putting the brakes on phagocytosis: "don't-eat-me" signaling in physiology and disease. EMBO Rep 2021; 22:e52564. [PMID: 34041845 DOI: 10.15252/embr.202152564] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/12/2021] [Accepted: 04/29/2021] [Indexed: 12/12/2022] Open
Abstract
Timely removal of dying or pathogenic cells by phagocytes is essential to maintaining host homeostasis. Phagocytes execute the clearance process with high fidelity while sparing healthy neighboring cells, and this process is at least partially regulated by the balance of "eat-me" and "don't-eat-me" signals expressed on the surface of host cells. Upon contact, eat-me signals activate "pro-phagocytic" receptors expressed on the phagocyte membrane and signal to promote phagocytosis. Conversely, don't-eat-me signals engage "anti-phagocytic" receptors to suppress phagocytosis. We review the current knowledge of don't-eat-me signaling in normal physiology and disease contexts where aberrant don't-eat-me signaling contributes to pathology.
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Affiliation(s)
- Shannon M Kelley
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA.,Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Kodi S Ravichandran
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA.,Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA.,VIB-UGent Center for Inflammation Research, Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
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Patel VI, Booth JL, Dozmorov M, Brown BR, Metcalf JP. Anthrax Edema and Lethal Toxins Differentially Target Human Lung and Blood Phagocytes. Toxins (Basel) 2020; 12:toxins12070464. [PMID: 32698436 PMCID: PMC7405021 DOI: 10.3390/toxins12070464] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/14/2020] [Accepted: 07/15/2020] [Indexed: 12/26/2022] Open
Abstract
Bacillus anthracis, the causative agent of inhalation anthrax, is a serious concern as a bioterrorism weapon. The vegetative form produces two exotoxins: Lethal toxin (LT) and edema toxin (ET). We recently characterized and compared six human airway and alveolar-resident phagocyte (AARP) subsets at the transcriptional and functional levels. In this study, we examined the effects of LT and ET on these subsets and human leukocytes. AARPs and leukocytes do not express high levels of the toxin receptors, tumor endothelium marker-8 (TEM8) and capillary morphogenesis protein-2 (CMG2). Less than 20% expressed surface TEM8, while less than 15% expressed CMG2. All cell types bound or internalized protective antigen, the common component of the two toxins, in a dose-dependent manner. Most protective antigen was likely internalized via macropinocytosis. Cells were not sensitive to LT-induced apoptosis or necrosis at concentrations up to 1000 ng/mL. However, toxin exposure inhibited B. anthracis spore internalization. This inhibition was driven primarily by ET in AARPs and LT in leukocytes. These results support a model of inhalation anthrax in which spores germinate and produce toxins. ET inhibits pathogen phagocytosis by AARPs, allowing alveolar escape. In late-stage disease, LT inhibits phagocytosis by leukocytes, allowing bacterial replication in the bloodstream.
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Affiliation(s)
- Vineet I. Patel
- Department of Medicine, Pulmonary, Critical Care & Sleep Medicine, the University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (V.I.P.); (J.L.B.); (B.R.B.)
| | - J. Leland Booth
- Department of Medicine, Pulmonary, Critical Care & Sleep Medicine, the University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (V.I.P.); (J.L.B.); (B.R.B.)
| | - Mikhail Dozmorov
- Department of Biostatistics, Virginia Commonwealth University, Richmond, VA 23298, USA;
| | - Brent R. Brown
- Department of Medicine, Pulmonary, Critical Care & Sleep Medicine, the University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (V.I.P.); (J.L.B.); (B.R.B.)
| | - Jordan P. Metcalf
- Department of Medicine, Pulmonary, Critical Care & Sleep Medicine, the University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (V.I.P.); (J.L.B.); (B.R.B.)
- Department of Microbiology and Immunology, the University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Veterans Affairs Medical Center, Oklahoma City, OK 73104, USA
- Correspondence:
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Tripathi A, Jain M, Chandra M, Parveen S, Yadav R, Collins BM, Maiti S, Datta S. EhC2B, a C2 domain-containing protein, promotes erythrophagocytosis in Entamoeba histolytica via actin nucleation. PLoS Pathog 2020; 16:e1008489. [PMID: 32365140 PMCID: PMC7197785 DOI: 10.1371/journal.ppat.1008489] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 03/23/2020] [Indexed: 12/17/2022] Open
Abstract
Remodelling of the actin cytoskeleton in response to external stimuli is obligatory for many cellular processes in the amoebic cell. A rapid and local rearrangement of the actin cytoskeleton is required for the development of the cellular protrusions during phagocytosis, trogocytosis, migration, and invasion. Here, we demonstrated that EhC2B, a C2 domain-containing protein, is an actin modulator. EhC2B was first identified as an effector of EhRab21 from E. histolytica. In vitro interaction studies including GST pull-down, fluorescence-based assay and ITC also corroborated with our observation. In the amoebic trophozoites, EhC2B accumulates at the pseudopods and the tips of phagocytic cups. FRAP based studies confirmed the recruitment and dynamics of EhC2B at the phagocytic cup. Moreover, we have shown the role of EhC2B in erythrophagocytosis. It is well known that calcium-dependent signal transduction is essential for the cytoskeletal dynamics during phagocytosis in the amoebic parasite. Using liposome pelleting assay, we demonstrated that EhC2B preferentially binds to the phosphatidylserine in the presence of calcium. The EhC2B mutants defective in calcium or lipid-binding failed to localise beneath the plasma membrane. The cells overexpressing these mutants have also shown a significant reduction in erythrophagocytosis. The role of EhC2B in erythrophagocytosis and pseudopod formation was also validated by siRNA-based gene knockdown approach. Finally, with the help of in vitro nucleation assay using fluorescence spectroscopy and total internal reflection fluorescence microscopy, we have established that EhC2B is an actin nucleator. Collectively, based on the results from the study, we propose that EhC2B acts like a molecular bridge which promotes membrane deformation via its actin nucleation activity during the progression of the phagocytic cup in a calcium-dependent manner.
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Affiliation(s)
- Aashutosh Tripathi
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Megha Jain
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Mintu Chandra
- Institute for Molecular Biosciences, University of Queensland, St Lucia, Australia
| | - Sameena Parveen
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Rupali Yadav
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Brett M. Collins
- Institute for Molecular Biosciences, University of Queensland, St Lucia, Australia
| | - Sankar Maiti
- Department of Biological Sciences, Indian Institute of Science Education and Research, Kolkata, India
| | - Sunando Datta
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
- * E-mail:
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Methamphetamine Impairs IgG1-Mediated Phagocytosis and Killing of Cryptococcus neoformans by J774.16 Macrophage- and NR-9640 Microglia-Like Cells. Infect Immun 2019; 87:IAI.00113-18. [PMID: 30510106 DOI: 10.1128/iai.00113-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 11/27/2018] [Indexed: 01/14/2023] Open
Abstract
The prevalence of methamphetamine (METH) use is estimated at ∼35 million people worldwide, with over 10 million users in the United States. Chronic METH abuse and dependence predispose the users to participate in risky behaviors that may result in the acquisition of HIV and AIDS-related infections. Cryptococcus neoformans is an encapsulated fungus that causes cryptococcosis, an opportunistic infection that has recently been associated with drug users. METH enhances C. neoformans pulmonary infection, facilitating its dissemination and penetration into the central nervous system in mice. C. neoformans is a facultative intracellular microorganism and an excellent model to study host-pathogen interactions. METH compromises phagocyte effector functions, which might have deleterious consequences on infection control. In this study, we investigated the role of METH in phagocytosis and antigen processing by J774.16 macrophage- and NR-9460 microglia-like cells in the presence of a specific IgG1 to C. neoformans capsular polysaccharide. METH inhibits antibody-mediated phagocytosis of cryptococci by macrophages and microglia, likely due to reduced expression of membrane-bound Fcγ receptors. METH interferes with phagocytic cells' phagosomal maturation, resulting in impaired fungal control. Phagocytic cell reduction in nitric oxide production during interactions with cryptococci was associated with decreased levels of tumor necrosis factor alpha (TNF-α) and lowered expression of Fcγ receptors. Importantly, pharmacological levels of METH in human blood and organs are cytotoxic to ∼20% of the phagocytes. Our findings suggest that METH abrogates immune cellular and molecular functions and may be deadly to phagocytic cells, which may result in increased susceptibility of users to acquire infectious diseases.
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Campos J, Varas-Godoy M, Haidar ZS. Physicochemical characterization of chitosan-hyaluronan-coated solid lipid nanoparticles for the targeted delivery of paclitaxel: a proof-of-concept study in breast cancer cells. Nanomedicine (Lond) 2017; 12:473-490. [DOI: 10.2217/nnm-2016-0371] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Aim: To investigate the potential of modified solid lipid nanoparticles (SLN) for the delivery of paclitaxel (PAX). Materials & methods: SLN loaded with PAX were prepared via modified high-pressure hot homogenization. Formulation parameters were optimized to obtain a high-quality delivery system. SLN cores were coated, layer-by-layer, with a chitosan and hyaluronan (HA) shell. Selectivity toward HA receptors was tested in a breast cancer cell line, MCF-7. Results: Stable and reproducible nano-sized and negatively charged nanoparticles resulted. Findings reveal that chitosan-HA-coated SLN facilitated the targeting, cellular uptake and the time-/dose-controlled delivery and release of PAX, enhancing intrinsic chemotherapeutic activities. Conclusion: SLN are suitable carrier candidates for nano-oncology given their localized, and potent cytotoxic potential overcoming multidrug-resistant cancer cells.
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Affiliation(s)
- Javier Campos
- Biomaterials & Tissue Engineering Research Group (BioMAT'X), Centro de Investigación Biomédica, Universidad de los Andes, Monseñor Álvaro del Portillo 12.455, Las Condes, Santiago, Chile
- Programa de Mejoramiento Institucional (PMI), I+D+i, Dirección de Innovación, Universidad de los Andes, Monseñor Álvaro del Portillo 12.455, Las Condes, Santiago, Chile
| | - Manuel Varas-Godoy
- Programa de Mejoramiento Institucional (PMI), I+D+i, Dirección de Innovación, Universidad de los Andes, Monseñor Álvaro del Portillo 12.455, Las Condes, Santiago, Chile
- Laboratorio Biología de la Reproducción, Centro de Investigación Biomédica, Universidad de los Andes, Monseñor Álvaro del Portillo 12.455, Las Condes, Santiago, Chile
| | - Ziyad Samir Haidar
- Biomaterials & Tissue Engineering Research Group (BioMAT'X), Centro de Investigación Biomédica, Universidad de los Andes, Monseñor Álvaro del Portillo 12.455, Las Condes, Santiago, Chile
- Programa de Mejoramiento Institucional (PMI), I+D+i, Dirección de Innovación, Universidad de los Andes, Monseñor Álvaro del Portillo 12.455, Las Condes, Santiago, Chile
- Faculty of Dentistry, Universidad de los Andes, Monseñor Álvaro del Portillo 12.455, Las Condes, Santiago, Chile
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Zwozdesky MA, Fei C, Lillico DME, Stafford JL. Imaging flow cytometry and GST pulldown assays provide new insights into channel catfish leukocyte immune-type receptor-mediated phagocytic pathways. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2017; 67:126-138. [PMID: 27984101 DOI: 10.1016/j.dci.2016.10.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 10/26/2016] [Accepted: 10/26/2016] [Indexed: 06/06/2023]
Abstract
Channel catfish (Ictalurus punctatus) leukocyte immune-type receptors (IpLITRs) control various innate immune cell effector responses including the phagocytic process. This large immunoregulatory receptor family also consists of multiple receptor-types with variable signaling abilities that is dependent on their inherent or acquired tyrosine-containing cytoplasmic tail (CYT) regions. For example, IpLITR 2.6b associates with the immunoreceptor tyrosine-based activation motif (ITAM)-containing adaptor molecule IpFcRγ-L, and when expressed in mammalian cells it activates phagocytosis using a similar profile of intracellular signaling mediators that also regulate the prototypical mammalian Fc receptor (FcR) phagocytic pathway. Alternatively, IpLITR 1.1b contains a long tyrosine-containing CYT with multifunctional capabilities including both inhibitory and stimulatory actions. Recently, we demonstrated that IpLITR 1.1b activates a unique phagocytic pathway involving the generation of multiple plasma membrane extensions that rapidly capture extracellular targets and secure them on the cell surface in phagocytic cup-like structures. Occasionally, these captured targets are completely engulfed albeit at a significantly lower rate than what was observed for IpLITR 2.6b. While this novel IpLITR 1.1b phagocytic activity is insensitive to classical blockers of phagocytosis, its distinct target capture and engulfment actions depend on the engagement of the actin polymerization machinery. However, it is not known how this protein translates target recognition into intracellular signaling events during this atypical mode of phagocytosis. Using imaging flow cytometry and GST pulldown assays, the aims of this study were to specifically examine what regions of the IpLITR 1.1b CYT trigger phagocytosis and to establish what profile of intracellular signaling molecules likely participate in its actions. Our results show that in stably transfected AD293 cells, the membrane proximal and distal CYT segments of IpLITR 1.1b independently regulate its phagocytic activities. These CYT regions were also shown to differentially recruit various SH2 domain-containing intracellular mediators, which provides new information about the dynamic immunoregulatory abilities of IpLITR 1.1b. Overall, this work further advances our understanding of how certain immunoregulatory receptor-types link extracellular target binding events to the actin polymerization machinery during a non-classical mode of phagocytosis.
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Affiliation(s)
- Myron A Zwozdesky
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Chenjie Fei
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Dustin M E Lillico
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - James L Stafford
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
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8
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Tian L, Choi SC, Murakami Y, Allen J, Morse HC, Qi CF, Krzewski K, Coligan JE. p85α recruitment by the CD300f phosphatidylserine receptor mediates apoptotic cell clearance required for autoimmunity suppression. Nat Commun 2016; 5:3146. [PMID: 24477292 DOI: 10.1038/ncomms4146] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 12/18/2013] [Indexed: 02/07/2023] Open
Abstract
Apoptotic cell (AC) clearance is essential for immune homeostasis. Here we show that mouse CD300f (CLM-1) recognizes outer membrane-exposed phosphatidylserine, and regulates the phagocytosis of ACs. CD300f accumulates in phagocytic cups at AC contact sites. Phosphorylation within CD300f cytoplasmic tail tyrosine-based motifs initiates signals that positively or negatively regulate AC phagocytosis. Y276 phosphorylation is necessary for enhanced CD300f-mediated phagocytosis through the recruitment of the p85α regulatory subunit of phosphatidylinositol-3-kinase (PI3K). CD300f-PI3K association leads to activation of downstream Rac/Cdc42 GTPase and mediates changes of F-actin that drive AC engulfment. Importantly, primary macrophages from CD300f-deficient mice have impaired phagocytosis of ACs. The biological consequence of CD300f deficiency is predisposition to autoimmune disease development, as FcγRIIB-deficient mice develop a systemic lupus erythematosus-like disease at a markedly accelerated rate if CD300f is absent. In this report we identify the mechanism and role of CD300f in AC phagocytosis and maintenance of immune homeostasis.
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Affiliation(s)
- Linjie Tian
- 1] Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA [2]
| | - Seung-Chul Choi
- 1] Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA [2]
| | - Yousuke Murakami
- Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA
| | - Joselyn Allen
- Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA
| | - Herbert C Morse
- Virology and Cellular Immunology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA
| | - Chen-Feng Qi
- Pathology core, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA
| | - Konrad Krzewski
- Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA
| | - John E Coligan
- Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA
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Martin TM, Plautz SA, Pannier AK. Temporal endogenous gene expression profiles in response to lipid-mediated transfection. J Gene Med 2015; 17:14-32. [PMID: 25663588 DOI: 10.1002/jgm.2821] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 02/01/2015] [Accepted: 02/03/2015] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Design of efficient nonviral gene delivery systems is limited as a result of the rudimentary understanding of the specific molecules and processes that facilitate DNA transfer. METHODS Lipoplexes formed with Lipofectamine 2000 (LF2000) and plasmid-encoding green fluorescent protein (GFP) were delivered to the HEK 293T cell line. After treating cells with lipoplexes, HG-U133 Affymetrix microarrays were used to identify endogenous genes differentially expressed between treated and untreated cells (2 h exposure) or between flow-separated transfected cells (GFP+) and treated, untransfected cells (GFP-) at 8, 16 and 24 h after lipoplex treatment. Cell priming studies were conducted using pharmacologic agents to alter endogenous levels of the identified differentially expressed genes to determine effect on transfection levels. RESULTS Relative to untreated cells 2 h after lipoplex treatment, only downregulated genes were identified ≥ 30-fold: ALMS1, ITGB1, FCGR3A, DOCK10 and ZDDHC13. Subsequently, relative to GFP- cells, the GFP+ cell population showed at least a five-fold upregulation of RAP1A and PACSIN3 (8 h) or HSPA6 and RAP1A (16 and 24 h). Pharmacologic studies altering endogenous levels for ALMS1, FCGR3A, and DOCK10 (involved in filopodia protrusions), ITGB1 (integrin signaling), ZDDHC13 (membrane trafficking) and PACSIN3 (proteolytic shedding of membrane receptors) were able to increase or decrease transgene production. CONCLUSIONS RAP1A, PACSIN3 and HSPA6 may help lipoplex-treated cells overcome a transcriptional shutdown due to treatment with lipoplexes and provide new targets for investigating molecular mechanisms of transfection or for enhancing transfection through cell priming or engineering of the nonviral gene delivery system.
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Affiliation(s)
- Timothy M Martin
- Department of Pharmaceutical Sciences, Durham Research Center II, University of Nebraska-Medical Center, Omaha, NE, USA
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Wen J, Jiang S, Chen Z, Zhao W, Yi Y, Yang R, Chen B. Apoptosis selectively induced in BEL-7402 cells by folic acid-modified magnetic nanoparticles combined with 100 Hz magnetic field. Int J Nanomedicine 2014; 9:2043-50. [PMID: 24790442 PMCID: PMC4003272 DOI: 10.2147/ijn.s60457] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
OBJECTIVE To explore the effect of folic acid-modified magnetic nanoparticles (FA-MNPs) combined with a 100 Hz extremely low-frequency electromagnetic field (ELF-EMF) on the apoptosis of liver cancer BEL-7402 cells. MATERIALS AND METHODS MNPs (20 nm) were prepared by coprecipitation, and then folic acid was coated onto MNPs to prepare FA-MNPs. BEL-7402 cells and HL7702 cells were selected as liver cancer cells and normal liver cells, respectively. The ELF-EMF was generated from a solenoid coil. Cellular uptake of NPs was determined by inductively coupled plasma atomic emission spectroscopy. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to evaluate cell inhibition. Apoptosis was analyzed by flow cytometry. Statistical analyses were performed using two-way analysis of variance. RESULTS FA-MNPs combined with a 100 Hz magnetic field significantly inhibited cell proliferation and induced higher apoptosis compared to either the ELF-EMF alone or FA-MNPs alone. FA-MNPs showed a better apoptosis effect and higher iron uptake in BEL-7402 cells compared to in HL7702 cells. On the basis of the ELF-EMF, higher doses of FA-MNPs brought higher apoptosis and higher iron uptake in either BEL-7402 cells or HL7702 cells. CONCLUSION These results suggest that FA-MNPs may induce apoptosis in a cellular iron uptake-dependent manner when combined with an ELF-EMF in BEL-7402 cells.
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Affiliation(s)
- Jian Wen
- Second Affiliated Hospital of Southeast University, Nanjing, People's Republic of China
| | - Shulian Jiang
- Second Affiliated Hospital of Southeast University, Nanjing, People's Republic of China
| | - Zhiqiang Chen
- Second Affiliated Hospital of Southeast University, Nanjing, People's Republic of China
| | - Wei Zhao
- Second Affiliated Hospital of Southeast University, Nanjing, People's Republic of China
| | - Yongxiang Yi
- Second Affiliated Hospital of Southeast University, Nanjing, People's Republic of China
| | - Ruili Yang
- Second Affiliated Hospital of Southeast University, Nanjing, People's Republic of China
| | - Baoan Chen
- Department of Hematology, Zhongda Hospital, Medical School, Southeast University, Nanjing, People's Republic of China
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Ke Y, Chen Z, Yang R. Yersinia pestis: mechanisms of entry into and resistance to the host cell. Front Cell Infect Microbiol 2013; 3:106. [PMID: 24400226 PMCID: PMC3871965 DOI: 10.3389/fcimb.2013.00106] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 12/10/2013] [Indexed: 12/28/2022] Open
Abstract
During infection, Yersinia, a facultative intracellular bacterial species, exhibits the ability to first invade host cells and then counteract phagocytosis by the host cells. During these two distinct stages, invasion or antiphagocytic factors assist bacteria in manipulating host cells to accomplish each of these functions; however, the mechanism through which Yersinia regulates these functions during each step remains unclear. Here, we discuss those factors that seem to function reversely and give some hypothesis about how bacteria switch between the two distinct status.
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Affiliation(s)
- Yuehua Ke
- Institute of Disease Control and Prevention, Academy of Military Medical Sciences Beijing, China ; Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences Beijing, China
| | - Zeliang Chen
- Institute of Disease Control and Prevention, Academy of Military Medical Sciences Beijing, China
| | - Ruifu Yang
- Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences Beijing, China
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12
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Acevedo-Morantes CY, Acevedo-Morantes MT, Suleiman-Rosado D, Ramírez-Vick JE. Evaluation of the cytotoxic effect of camptothecin solid lipid nanoparticles on MCF7 cells. Drug Deliv 2013; 20:338-48. [PMID: 24024505 DOI: 10.3109/10717544.2013.834412] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Camptothecin (CPT) and its analogs exhibit remarkable anti-tumor activity, due to their ability to inhibit DNA topoisomerase I. However, its use is limited by the lack of solubility and stability of the active lactone form. An attractive alternative is the encapsulation of CPT within liposomes. In this study, CPT was incorporated into solid lipid nanoparticles (SLN) based on the triglyceride, Compritol 888 ATO, using supercritical fluid technology without requiring the use of harmful solvents. This drug delivery system was characterized and its cytotoxicity effect was evaluated by measuring MCF7 and MCF10A cell viability as a function of drug loading during a 48-h treatment. Results showed that after 10 h of treatment, MCF7 cells displayed an IC50 of 0.23±0.034 μM at a 1:5 (CPT:SLN) loading and 0.22±0.027 μM at a 1:10 loading, whereas MCF10A cells displayed an IC50 of 0.40±0.036 μM at 1:5 and 0.60±0.063 μM at 1:10. On the other hand, the IC50 of free CPT was 0.57±0.035 μM and 1.07±0.077 μM for MCF7 and MCF10A cells, respectively. Cellular uptake and retention measurements in both cells displayed a two-fold increase when using the SLN formulation. The results from this study showed that the cytotoxic effects of CPT in a SLN formulation improved when compared with those seen with free CPT. The results of this study showed that delivery of CPT as a SLN formulation could be a promising strategy for enhancing its chemotherapeutic effects.
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Rollet-Labelle E, Vaillancourt M, Marois L, Newkirk MM, Poubelle PE, Naccache PH. Cross-linking of IgGs bound on circulating neutrophils leads to an activation of endothelial cells: possible role of rheumatoid factors in rheumatoid arthritis-associated vascular dysfunction. J Inflamm (Lond) 2013; 10:27. [PMID: 23902799 PMCID: PMC3734015 DOI: 10.1186/1476-9255-10-27] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 07/25/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Rheumatoid arthritis is characterized by the presence of circulating auto-antibodies, including rheumatoid factors, which recognize the Fc portion of IgGs. The neutrophil is the most abundant circulating leukocyte and it expresses high levels of FcγRs on its surface. The aim of the present study was to examine the capacity of circulating human neutrophils to be activated by rheumatoid factors and the consequences of these events on endothelium. METHODS Neutrophil-bound IgGs were cross-linked with anti-human IgGs to mimick the presence of circulating rheumatoid factors and FcγRs-dependent signalling events and functions were examined. The IgG and IgM composition of rheumatoid factors isolated from the serum of RA patients was characterized. Adhesion of neutrophils to endothelial cells was quantified in response to the addition of rheumatoid factors. RESULTS Cross-linking of IgGs bound on neutrophils leads to FcγRs-dependent tyrosine phosphorylation, mobilisation of intracellular calcium and the extracellular release of superoxide anions and lysozyme. Incubation of endothelial cells with the supernatant of activated neutrophils increases ICAM-1 expression and IL-8 production by endothelial cells. Finally, rheumatoid factors enhance neutrophil adhesion to endothelial cells. CONCLUSIONS Our results show that activation of neutrophils' FcγRs by rheumatoid factors could participate in rheumatoid arthritis-associated vascular damage.
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Affiliation(s)
- Emmanuelle Rollet-Labelle
- Départements de Microbiologie-Infectiologie et Immunologie et de Médecine, Centre de recherche en rhumatologie et immunologie, Centre de recherche du CHU de Québec, Université Laval, Québec, QC, Canada
| | - Myriam Vaillancourt
- Départements de Microbiologie-Infectiologie et Immunologie et de Médecine, Centre de recherche en rhumatologie et immunologie, Centre de recherche du CHU de Québec, Université Laval, Québec, QC, Canada
| | - Louis Marois
- Départements de Microbiologie-Infectiologie et Immunologie et de Médecine, Centre de recherche en rhumatologie et immunologie, Centre de recherche du CHU de Québec, Université Laval, Québec, QC, Canada
| | - Marianna M Newkirk
- Department of Medicine, Division of Rheumatology, Research Institute of McGill University Health Centre, McGill University, Montreal, QC, Canada
| | - Patrice E Poubelle
- Départements de Microbiologie-Infectiologie et Immunologie et de Médecine, Faculté de médecine, Université Laval, Québec, QC, Canada
| | - Paul H Naccache
- Départements de Microbiologie-Infectiologie et Immunologie et de Médecine, Centre de recherche en rhumatologie et immunologie, Centre de recherche du CHU de Québec, Université Laval, Québec, QC, Canada
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Ryu KY, Cho GS, Piao HZ, Kim WK. Role of TGF-β in Survival of Phagocytizing Microglia: Autocrine Suppression of TNF-α Production and Oxidative Stress. Exp Neurobiol 2012; 21:151-7. [PMID: 23319875 PMCID: PMC3538179 DOI: 10.5607/en.2012.21.4.151] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 12/10/2012] [Indexed: 01/24/2023] Open
Abstract
Microglia are recognized as residential macrophageal cells in the brain. Activated microglia play a critical role in removal of dead or damaged cells through phagocytosis activity. During phagocytosis, however, microglia should survive under the harmful condition of self-producing ROS and pro-inflammatory mediators. TGF-β has been known as a classic anti-inflammatory cytokine and controls both initiation and resolution of inflammation by counter-acting inflammatory cytokines. In the present study, to understand the self-protective mechanism, we studied time-dependent change of TNF-α and TGF-β production in microglia phagocytizing opsonized-beads (i.e., polystyrene microspheres). We found that microglia phagocytized opsonized-bead in a time-dependent manner and simultaneously produced both TNF-α and TGF-β. However, while TNF-α production gradually decreased after 6 h, TGF-β production remained at increased level. Microglial cells pre-treated with lipopolysaccharides (a strong immunostimulant, LPS) synergistically increased the production of TNF-α and TGF-β both. However, LPS-pretreated microglia produced TNF-α in a more sustained manner and became more vulnerable, probably due to the marked and sustained production of TNF-α and reduced TGF-β. Intracellular oxidative stress appears to change in parallel with the microglial production of TNF-α. These results indicate TGF-β contributes for the survival of phagocytizing microglia through autocrine suppression of TNF-α production and oxidative stress.
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Affiliation(s)
- Keun-Young Ryu
- College of Medicine, Korea University, Seoul 136-705, Korea
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15
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Li X, Baskin JG, Mangan EK, Su K, Gibson AW, Ji C, Edberg JC, Kimberly RP. The unique cytoplasmic domain of human FcγRIIIA regulates receptor-mediated function. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2012; 189:4284-94. [PMID: 23024279 PMCID: PMC3478424 DOI: 10.4049/jimmunol.1200704] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Ligand specificity characterizes receptors for Abs and many other immune receptors, but the common use of the FcR γ-chain as their signaling subunit challenges the concept that these receptors are functionally distinct. We hypothesized that elements for specificity might be determined by the unique cytoplasmic domain (CY) sequences of the ligand-binding α-chains of γ-chain-associated receptors. Among Fcγ receptors, a protein kinase C (PKC) phosphorylation consensus motif [RSSTR], identified within the FcγRIIIa (CD16A) CY by in silico analysis, is specifically phosphorylated by PKCs, unlike other FcRs. Phosphorylated CD16A mediates a more robust calcium flux, tyrosine phosphorylation of Syk, and proinflammatory cytokine production, whereas nonphosphorylatable CD16A is more effective at activation of the Gab2/PI3K pathway, leading to enhanced degranulation. S100A4, a specific protein-binding partner for CD16A-CY newly identified by yeast two-hybrid analysis, inhibits phosphorylation of CD16A-CY by PKC in vitro, and reduction of S100A4 levels in vivo enhances receptor phosphorylation upon cross-linking. Taken together, PKC-mediated phosphorylation of CD16A modulates distinct signaling pathways engaged by the receptor. Calcium-activated binding of S100A4 to CD16A, promoted by the initial calcium flux, attenuates the phosphorylation of CY, and, acting as a molecular switch, may both serve as a negative feedback on cytokine production pathways during sustained receptor engagement and favor a shift to degranulation, consistent with the importance of granule release following conjugate formation between CD16A(+) effector cells and target cells. This switch mechanism points to new therapeutic targets and provides a framework for understanding novel receptor polymorphisms.
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Affiliation(s)
- Xiaoli Li
- Division of Clinical Immunology and Rheumatology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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16
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Vishniakova KS, Kireev II, Dunina-Barkovskaya AY. Effects of cell culture density on phagocytosis parameters in IC-21 macrophages. BIOCHEMISTRY MOSCOW SUPPLEMENT SERIES A-MEMBRANE AND CELL BIOLOGY 2011. [DOI: 10.1134/s1990747811050138] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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17
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Page TH, D'Souza Z, Nakanishi S, Serikawa T, Pusey CD, Aitman TJ, Cook HT, Behmoaras J. Role of novel rat-specific Fc receptor in macrophage activation associated with crescentic glomerulonephritis. J Biol Chem 2011; 287:5710-9. [PMID: 22184119 PMCID: PMC3285343 DOI: 10.1074/jbc.m111.260695] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Crescentic glomerulonephritis (Crgn) is a complex disease where the initial insult is often the glomerular deposition of antibodies against intrinsic or deposited antigens in the glomerulus. The role of Fc receptors in the induction and progression of Crgn is increasingly recognized, and our previous studies have shown that copy number variation in Fcgr3 partially explains the genetic susceptibility of the Wistar-Kyoto (WKY) rat to nephrotoxic nephritis, a rat model of Crgn. The Fcgr3-related sequence (Fcgr3-rs) is a novel rat-specific Fc receptor with a cytoplasmic domain 6 amino acids longer than its paralogue, Fcgr3. The Fcgr3-rs gene is deleted from the WKY rat genome, and this deletion is associated with enhanced macrophage activity in this strain. Here, we investigated the mechanism by which the deletion of Fcgr3-rs in the WKY strain leads to increased macrophage activation. By lentivirus-mediated gene delivery, we generated stably transduced U937 cells expressing either Fcgr3-rs or Fcgr3. In these cells, which lack endogenous Fcgr3 receptors, we show that Fcgr3-rs interacts with the common Fc-γ chain but that Fc receptor-mediated phagocytosis and signaling are defective. Furthermore, in primary macrophages, expression of Fcgr3-rs inhibits Fc receptor-mediated functions, because WKY bone marrow-derived macrophages transduced with Fcgr3-rs had significantly reduced phagocytic activity. This inhibitory effect on phagocytosis was mediated by the novel cytoplasmic domain of Fcgr3-rs. These results suggest that Fcgr3-rs may act to inhibit Fcgr3-mediated signaling and phagocytosis and could be considered as a novel mechanism in the modulation of Fc receptor-mediated cell activation in autoimmune diseases.
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Affiliation(s)
- Theresa H Page
- Kennedy Institute of Rheumatology Division, Imperial College London, London W6 8LH, United Kingdom
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18
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CAI JIANLING, HUANG NING, ZHANG YONG. SYNTHESIS OF POLYSTYRENE ENCAPSULATEDZnS-COATEDCdSeNANOCOMPOSITES MODIFIED WITH PLL–PEI–PEG–FA. INTERNATIONAL JOURNAL OF NANOSCIENCE 2011. [DOI: 10.1142/s0219581x05003097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Current cell tags using dyes lose their luminescence quickly and are not suitable for optical barcoding. Semiconductor quantum dots (QDs), on the other hand, can be engineered to emit different wavelengths, thus permitting tagging of various cells at the same time. Core/shell luminescent quantum dots, cadmium selenide ( CdSe ) and zinc sulphide ( ZnS ), were synthesized and incorporated into polystyrene (PS) particles grafted with carboxyl groups using microemulsion polymerization method. Highly luminescent monodispersed PS particles with diameters from 30 nm to 50 nm were chosen for subsequent surface modification. Two series of surface modifications were carried out with PS particles. One was modified with poly(L-Lysine) (PLL), polyethylenimine (PEI), Poly(Ethylene Glycol) (PEG) and folic acid (FA) side chains in sequence through chemical bonding. Another was conjugated with PEG and FA in sequence. The folic acid side chains can enter target cells via folate receptors and assisted in the uptake of the luminescent particles into the cells. This property allows them to be used as fluorescent labels for marking their ingress into cells and also for a cornucopia of biomedical applications.
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Affiliation(s)
- JIANLING CAI
- Division of Bioengineering, Faculty of Engineering, Blk, EA-03-12, National University of Singapore, 9, Engineering Drive 1, Singapore 117576, Singapore
| | - NING HUANG
- Division of Bioengineering, Faculty of Engineering, Blk, EA-03-12, National University of Singapore, 9, Engineering Drive 1, Singapore 117576, Singapore
| | - YONG ZHANG
- Division of Bioengineering, Faculty of Engineering, Blk, EA-03-12, National University of Singapore, 9, Engineering Drive 1, Singapore 117576, Singapore
- Nanosciene and Nanotechnology Initiative, National University of Singapore, Singapore
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Marois L, Vaillancourt M, Paré G, Gagné V, Fernandes MJG, Rollet-Labelle E, Naccache PH. CIN85 modulates the down-regulation of Fc gammaRIIa expression and function by c-Cbl in a PKC-dependent manner in human neutrophils. J Biol Chem 2011; 286:15073-84. [PMID: 21372129 PMCID: PMC3083175 DOI: 10.1074/jbc.m110.213660] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 02/21/2011] [Indexed: 01/04/2023] Open
Abstract
We previously described a non-classical mechanism that arrests FcγRIIa signaling in human neutrophils once engaged by immune complexes or opsonized pathogens. The engagement of FcγRIIa leads to its ubiquitination by the ubiquitin ligase c-Cbl and degradation by the proteasome. Herein, we further examined some of the events regulating this novel pathway. The adaptor protein CIN85 was described in other systems to be involved in the regulation of the c-Cbl-dependent pathway. We found that CIN85 is expressed in human neutrophils and that it translocates like c-Cbl from the cytosol to the plasma membrane following receptor cross-linking. CIN85 was also recruited to the same subset of high density detergent-resistant membrane fractions in which stimulated FcγRIIa partitioned with c-Cbl. The integrity of these microdomains is essential to the FcγRIIa degradation process because the cholesterol-depleting agent methyl-β-cyclodextrin inhibits this event. Silencing the expression of CIN85 by siRNA in dibutyryl cyclic AMP-differentiated PLB 985 cells prevented FcγRIIa degradation and increased IgG-mediated phagocytosis. Confocal microscopy revealed that the presence of CIN85 is essential to the proper sorting of FcγRIIa during endocytosis. We also provide direct evidence that CIN85 is a substrate of serine/threonine kinase PKCs. Classical PKCs positively regulate FcγRIIa ubiquitination and degradation because these events were inhibited by Gö6976, a classical PKC inhibitor. We conclude that the ubiquitination and degradation of stimulated FcγRIIa mediated by c-Cbl are positively regulated by the adaptor protein CIN85 in a PKC-dependent manner and that these events contribute to the termination of FcγRIIa signaling.
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Affiliation(s)
- Louis Marois
- From the Centre de Recherche en Rhumatologie et Immunologie, Centre de Recherche du CHUQ, Département de Microbiologie-Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec, Québec G1V 4G2, Canada
| | - Myriam Vaillancourt
- From the Centre de Recherche en Rhumatologie et Immunologie, Centre de Recherche du CHUQ, Département de Microbiologie-Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec, Québec G1V 4G2, Canada
| | - Guillaume Paré
- From the Centre de Recherche en Rhumatologie et Immunologie, Centre de Recherche du CHUQ, Département de Microbiologie-Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec, Québec G1V 4G2, Canada
| | - Valérie Gagné
- From the Centre de Recherche en Rhumatologie et Immunologie, Centre de Recherche du CHUQ, Département de Microbiologie-Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec, Québec G1V 4G2, Canada
| | - Maria J. G. Fernandes
- From the Centre de Recherche en Rhumatologie et Immunologie, Centre de Recherche du CHUQ, Département de Microbiologie-Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec, Québec G1V 4G2, Canada
| | - Emmanuelle Rollet-Labelle
- From the Centre de Recherche en Rhumatologie et Immunologie, Centre de Recherche du CHUQ, Département de Microbiologie-Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec, Québec G1V 4G2, Canada
| | - Paul H. Naccache
- From the Centre de Recherche en Rhumatologie et Immunologie, Centre de Recherche du CHUQ, Département de Microbiologie-Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec, Québec G1V 4G2, Canada
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20
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Saltan N, Kutlu HM, Hür D, Işcan A, Say R. Interaction of cancer cells with magnetic nanoparticles modified by methacrylamido-folic acid. Int J Nanomedicine 2011; 6:477-84. [PMID: 21468352 PMCID: PMC3065795 DOI: 10.2147/ijn.s16803] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Magnetic nanoparticles show great promise for use as tools in a wide variety of biomedical applications. The purpose of this study was to investigate the potential effects of methacrylamido-folic acid (Ma-Fol)-modified magnetic nanoparticles on 5RP7 (H-ras-transformed rat embryonic fibroblasts) and NIH/3T3 (normal mouse embryonic fibroblasts). METHODS The cytotoxicity and viability of 5RP7 and NIH/3T3 cells were detected. The percentage of cells undergoing apoptosis was analyzed by flow cytometry using Annexin V-fluorescein isothiocyanate staining. Nanoparticle internalization into 5RP7 and NIH/3T3 cells was visualized by transmission electron microscopy. CONCLUSION In this study, folic acid coupled to the surface of iron oxide for selective binding to cancer cells and immobilized the surfaces of magnetic nanoparticles. This complex improves cell internalization and targeting of cancer cells. We detected increased apoptosis using flow cytometry and transmission electron microscopy. RESULTS Folic acid modification of magnetic nanoparticles could be used to facilitate uptake to specific cancer cells for cancer therapy and diagnosis. Our results showed that the uptake of folic-acid modified nanoparticles by 5RP7 cancer cells was also much higher than that of 3T3 cells. This modification can be used for successful targeting of cancer cells expressing the folate receptor.
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Affiliation(s)
- Nagehan Saltan
- Department of Pharmaceutical Botanics, Faculty of Pharmacy, Anadolu University, Eskişehir, Turkey
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21
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Marois L, Paré G, Vaillancourt M, Rollet-Labelle E, Naccache PH. Fc gammaRIIIb triggers raft-dependent calcium influx in IgG-mediated responses in human neutrophils. J Biol Chem 2010; 286:3509-19. [PMID: 21123174 DOI: 10.1074/jbc.m110.169516] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human neutrophils constitutively express a unique combination of FcγRs, namely FcγRIIa and FcγRIIIb. Numerous lines of evidence support the concept that these FcγRs generate only partially characterized intracellular signals. However, despite the fact that both receptors are likely to be engaged simultaneously in a physiological setting, no recent publications have investigated the distinct, although partially convergent, results of their joint activation in IgG-dependent responses. To examine the significance of the co-expression of FcγRIIa and FcγRIIIb on human neutrophils, we analyzed the neutrophil responses to stimuli that engage these FcγRs, namely the phagocytosis of human IgG-opsonized zymosan and the responses to heat-aggregated IgGs. Blocking antibodies to either FcγR significantly decreased the phagocytic index and the stimulated production of superoxide anions. Both receptors are required for optimal IgG-dependent responses by human neutrophils. On the other hand, only blocking antibodies to FcγRIIIb, but not to FcγRIIa, inhibited the mobilization of calcium in response to heat-aggregated IgGs. Furthermore, phagocytosis of IgG-opsonized zymosan by human neutrophils required an extracellular influx of calcium that was blocked only by antibodies against FcγRIIIb. We also observed that this calcium influx as well as the IgG-dependent phagocytosis were dependent on the integrity of the plasma membrane detergent-resistant microdomains to which both isoforms were recruited following stimulation by heat-aggregated IgGs. These data clarify the mechanisms that regulate the FcγRs constitutively expressed on human neutrophils, describe a specific contribution of FcγRIIIb at the level of the mobilization of calcium, and provide evidence for a crucial role of detergent-resistant microdomains in this process.
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Affiliation(s)
- Louis Marois
- Centre de Recherche du Centre Hospitalier Universitaire de Québec, Department of Microbiology-Infectiology and Immunology, Faculty of Medicine, Laval University, Québec City, Québec G1V 4G2, Canada
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22
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Tsai RK, Rodriguez PL, Discher DE. Self inhibition of phagocytosis: the affinity of 'marker of self' CD47 for SIRPalpha dictates potency of inhibition but only at low expression levels. Blood Cells Mol Dis 2010; 45:67-74. [PMID: 20299253 DOI: 10.1016/j.bcmd.2010.02.016] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2010] [Accepted: 01/19/2010] [Indexed: 12/20/2022]
Abstract
Phagocytes engulf foreign cells but not 'self' in part because self cells express CD47 as a ligand for signal regulatory protein SIRPalpha, which inhibits phagocytosis. Motivated by reports of upregulation of CD47 on both normal and cancerous stem cells [1: Jaiswal et al., 2009] and also by polymorphisms in SIRPalpha [2: Takenaka et al., 2007], we show here that inhibition of engulfment correlates with affinity of CD47 for SIRPalpha - but only at low levels of CD47. One common human polymorph of SIRPalpha is studied and binds more strongly to human-CD47 than to mouse-CD47 (K(d) approximately 0.12 microM and 6.9 microM, respectively) and does not bind sheep red blood cells (RBCs) - which are well-established targets of human macrophages; in comparison, a common mouse polymorph of SIRPalpha binds with similar affinity to human and mouse CD47 (K(d) approximately 0.22 microM). Using immunoglobulin (IgG)-opsonized particles with varying levels of either human- or mouse-CD47, the effective inhibition constants K(i) for blocking phagocytosis are then determined with both human- and mouse-derived macrophages. Only human phagocytes show significant differences in man versus mouse K(i)'s and only at CD47 levels below normal densities for RBCs. While phospho-signaling through human-SIRPalpha shows similar trends, consistent again with the affinity differences, saturating levels of CD47 (>K(i)) can signal and inhibit phagocytosis regardless of man versus mouse. Quantitative analyses here prompt more complete characterizations of both CD47 levels and SIRPalpha polymorphisms when attempting to study in vivo effects of these key proteins in innate immunity.
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Affiliation(s)
- Richard K Tsai
- Biophysical Engineering Lab, University of Pennsylvania, Philadelphia, PA 19104, USA.
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23
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Fens MHAM, Storm G, Pelgrim RCM, Ultee A, Byrne AT, Gaillard CA, van Solinge WW, Schiffelers RM. Erythrophagocytosis by angiogenic endothelial cells is enhanced by loss of erythrocyte deformability. Exp Hematol 2010; 38:282-91. [PMID: 20146933 DOI: 10.1016/j.exphem.2010.02.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2009] [Revised: 01/26/2010] [Accepted: 02/02/2010] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Angiogenic endothelial cells can function as phagocytes, and phagocytosis is initiated via the opsonin lactadherin. In this study, we examined the interaction between lactadherin-opsonized erythrocytes with reduced deformability and angiogenic endothelium, as loss of deformability is characteristic for suicidal and aged erythrocytes. MATERIALS AND METHODS We used the Arg-Gly-Asp (RGD)-modified erythrocyte model and investigated the deformability parameter by cross-linking erythrocyte membranes through treatment with glutaraldehyde. Association in vitro with primary endothelial cells was detected by flow cytometry and visualized by light, fluorescent, and electron microscopy. Involvement of two crucial factors in phagocytosis, alpha(v)-integrins and Rho guanosine triphosphatase family member Rac1, was studied using small interfering RNA technology. Modified erythrocytes were administered in vivo into tumor-bearing mice to detect phagocytosis by endothelial cells. RESULTS Glutaraldehyde-treated (rigid) RGD-modified erythrocytes showed a strongly enhanced endothelial cell association compared to flexible RGD-modified erythrocytes. Knockdown by small interfering RNA lipoplexes of alpha(v)-integrins and Rac1 confirmed classical tethering and internalization of rigid RGD-erythrocytes. Upon in vivo administration, tumor endothelium showed pronounced erythrophagocytosis. CONCLUSION The pronounced phagocytosis of opsonized erythrocytes with reduced deformability by angiogenic growth factor-activated endothelial cells evokes new insights in endothelial cell function and suggests a role for these endothelial cells in (hematological) disorders because of their capacity to clear disordered erythrocytes.
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Affiliation(s)
- Marcel H A M Fens
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht, The Netherlands
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A mechanical bottleneck explains the variation in cup growth during FcgammaR phagocytosis. Mol Syst Biol 2009; 5:298. [PMID: 19690567 PMCID: PMC2736656 DOI: 10.1038/msb.2009.59] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Accepted: 07/15/2009] [Indexed: 11/29/2022] Open
Abstract
Phagocytosis is the process by which cells internalize particulate material, and is of central importance to immunity, homeostasis and development. Here, we study the internalization of immunoglobulin G-coated particles in cells transfected with Fcγ receptors (FcγRs) through the formation of an enveloping phagocytic cup. Using confocal microscopy, we precisely track the location of fluorescently tagged FcγRs during cup growth. Surprisingly, we found that phagocytic cups growing around identical spherical particles showed great variability even within a single cell and exhibited two eventual fates: a cup either stalled before forming a half-cup or it proceeded until the particle was fully enveloped. We explain these observations in terms of a mechanical bottleneck using a simple mathematical model of the overall process of cup growth. The model predicts that reducing F-actin concentration levels, and hence the deforming force, does not necessarily lead to stalled cups, a prediction we verify experimentally. Our analysis gives a coherent explanation for the importance of geometry in phagocytic uptake and provides a unifying framework for integrating the key processes, both biochemical and mechanical, occurring during cup growth.
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25
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Li XB, Hou XL, Mao Q, Zhao YL, Cheng YX, Wang Q. Toxic effects of copper on antioxidative and metabolic enzymes of the marine gastropod, Onchidium struma. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2009; 56:776-784. [PMID: 19214621 DOI: 10.1007/s00244-009-9290-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2008] [Accepted: 01/20/2009] [Indexed: 05/27/2023]
Abstract
The goals of this study were to evaluate the acute and sublethal toxicity of copper (Cu(2+)) on the marine gastropod, Onchidium struma, and to examine the utility of enzymatic parameters as indicators of Cu(2+) exposure. In a semistatic renewal test, the 96-hour median lethal concentration of Cu(2+) for O. struma, 74.80 mg/L, was higher than that for other intertidal species. The activities of the antioxidative enzymes, Cu/Zn superoxide dismutase (Cu/Zn-SOD) and catalase (CAT), and those of the metabolic enzymes-acid phosphatase (ACP), alkaline phosphatase (AKP), glutamic-oxaloacetic transaminase (GOT), and glutamic-pyruvic transaminase (GPT) -in both hepatopancreas and muscle were determined after a 1-week exposure to Cu(2+) (range 1.35 to 4.20 mg/L). The activities of both Cu/Zn-SOD and CAT were higher in hepatopancreas than muscle. In addition, there was a negative correlation between Cu(2+) concentration and Cu/Zn-SOD activity in hepatopancreas, whereas a positive correlation was observed for CAT activity. Concentration-dependent changes in ACP and AKP activity showed a similar trend in hepatopancreas, increasing then decreasing and, finally, a slight increase. In contrast, ACP activity was positively correlated with Cu(2+) across the concentration range tested. In both hepatopancreas and muscle, both GOT and GPT were activated by lower concentrations of Cu(2+) and inhibited at higher concentrations.
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Affiliation(s)
- Xiao-bo Li
- School of Life Science, East China Normal University, Shanghai, China
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26
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Marois L, Vaillancourt M, Marois S, Proulx S, Paré G, Rollet-Labelle E, Naccache PH. The ubiquitin ligase c-Cbl down-regulates FcgammaRIIa activation in human neutrophils. THE JOURNAL OF IMMUNOLOGY 2009; 182:2374-84. [PMID: 19201892 DOI: 10.4049/jimmunol.0801420] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Little is known about the mechanisms that arrest FcgammaRIIa signaling in human neutrophils once engaged by immune complexes or opsonized pathogens. In our previous studies, we observed a loss of immunoreactivity of Abs directed against FcgammaRIIa following its cross-linking. In this study, we report on the mechanisms involved in this event. A stimulated internalization of FcgammaRIIa leading to the down-regulation of its surface expression was observed by flow cytometry and confocal microscopy. Immunoprecipitation of the receptor showed that FcgammaRIIa is ubiquitinated after stimulation. MG132 and clasto-lactacystin beta-lactone inhibited the loss of immunoreactivity of FcgammaRIIa, suggesting that this receptor was down-regulated via the proteasomal pathway. The E3 ubiquitin ligase c-Cbl was found to translocate from the cytosol to the plasma membrane following receptor cross-linking. Furthermore, c-Cbl was recruited to the same subset of high-density, detergent-resistant membrane fractions as stimulated FcgammaRIIa itself. Silencing the expression of c-Cbl by small interfering RNA decreased FcgammaRIIa ubiquitination and prevented its degradation without affecting the internalisation process. It also prolonged the stimulation of the tyrosine phosphorylation response to the cross-linking of the receptor. We conclude that c-Cbl mediates the ubiquitination of stimulated FcgammaRIIa and thereby contributes to the termination of FcgammaRIIa signaling via its proteasomal degradation, thus leading to the down-regulation of neutrophil signalisation and function (phagocytosis) through this receptor.
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Affiliation(s)
- Louis Marois
- Centre de recherche en rhumatologie et immunologie, Centre de recherche du Centre hospitalier universitaire de Québec, Department of Medicine, Faculty of Medicine, Laval University, Quebec, Canada
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Tsai RK, Discher DE. Inhibition of "self" engulfment through deactivation of myosin-II at the phagocytic synapse between human cells. ACTA ACUST UNITED AC 2008; 180:989-1003. [PMID: 18332220 PMCID: PMC2265407 DOI: 10.1083/jcb.200708043] [Citation(s) in RCA: 344] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Phagocytosis of foreign cells or particles by macrophages is a rapid process that is inefficient when faced with “self” cells that display CD47—although signaling mechanisms in self-recognition have remained largely unknown. With human macrophages, we show the phagocytic synapse at cell contacts involves a basal level of actin-driven phagocytosis that, in the absence of species-specific CD47 signaling, is made more efficient by phospho-activated myosin. We use “foreign” sheep red blood cells (RBCs) together with CD47-blocked, antibody-opsonized human RBCs in order to visualize synaptic accumulation of phosphotyrosine, paxillin, F-actin, and the major motor isoform, nonmuscle myosin-IIA. When CD47 is functional, the macrophage counter-receptor and phosphatase-activator SIRPα localizes to the synapse, suppressing accumulation of phosphotyrosine and myosin without affecting F-actin. On both RBCs and microbeads, human CD47 potently inhibits phagocytosis as does direct inhibition of myosin. CD47–SIRPα interaction initiates a dephosphorylation cascade directed in part at phosphotyrosine in myosin. A point mutation turns off this motor's contribution to phagocytosis, suggesting that self-recognition inhibits contractile engulfment.
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Affiliation(s)
- Richard K Tsai
- Biophysical Engineering Laboratory, University of Pennsylvania, Philadelphia, PA 19104, USA
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Sapinoro R, Volcy K, Rodrigo WWSI, Schlesinger JJ, Dewhurst S. Fc receptor-mediated, antibody-dependent enhancement of bacteriophage lambda-mediated gene transfer in mammalian cells. Virology 2008; 373:274-86. [PMID: 18191979 DOI: 10.1016/j.virol.2007.12.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Revised: 09/11/2007] [Accepted: 12/03/2007] [Indexed: 12/23/2022]
Abstract
Lambda phage vectors mediate gene transfer in cultured mammalian cells and in live mice, and in vivo phage-mediated gene expression is increased when mice are pre-immunized with bacteriophage lambda. We now show that, like eukaryotic viruses, bacteriophage vectors are subject to Fc receptor-mediated, antibody-dependent enhancement of infection in mammalian cells. Antibody-dependent enhancement of phage gene transfer required FcgammaRI, but not its associated gamma-chain, and was not supported by other FcgammaR family members (FcgammaRIIA, FcgammaRIIB, and FcgammaRIII). Studies using chlorpromazine and latrunculin A revealed an important role for clathrin-mediated endocytosis (chlorpromazine) and actin filaments (latrunculin A) in antibody-enhanced phage gene transfer. This was confirmed by experiments using inhibitors of endosomal acidification (bafilomycin A1, monensin) and by immunocytochemical colocalization of internalized phage particles with early endosome-associated protein-1 (EAA1). In contrast, microtubule-targeting agents (nocodazole, taxol) increased the efficiency of antibody-enhanced phage gene transfer. These results reveal an unexpected antibody-dependent, FcgammaRI-mediated enhancement of phage transduction in mammalian cells, and suggest new approaches to improve bacteriophage-mediated gene transfer.
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Affiliation(s)
- Ramil Sapinoro
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, USA
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29
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Meng XX, Wan JQ, Jing M, Zhao SG, Cai W, Liu EZ. Specific targeting of gliomas with multifunctional superparamagnetic iron oxide nanoparticle optical and magnetic resonance imaging contrast agents. Acta Pharmacol Sin 2007; 28:2019-26. [PMID: 18031618 DOI: 10.1111/j.1745-7254.2007.00661.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
AIM To determine whether glioma cells can be specifically and efficiently targeted by superparamagnetic iron oxide nanoparticle (SPIO)-fluorescein isothiocyanate (FITC)-chlorotoxin (SPIOFC) that is detectable by magnetic resonance imaging (MRI) and optical imaging. METHODS SPIOFC was synthesized by conjugating SPIO with FITC and chlorotoxin. Glioma cells (human U251-MG and rat C6) were cultured with SPIOFC and SPIOF (SPIO-FITC), respectively. Neural cells were treated with SPIOFC as the control for SPIOFC-targeted glioma cells. The internalization of SPIOFC by glioma cells was assessed by MRI and was quantified using inductively-coupled plasma emission spectroscopy. The optical imaging ability of SPIOFC was evaluated by confocal laser scanning microscopy. RESULTS Iron per cell of U251 (72.5+/-1.8 pg) and C6 (74.9+/-2.2 pg) cells cultured with SPIOFC were significantly more than those of U251 (6.6+/-1.0 pg) and C6 (7.1+/-0.8 pg) cells incubated with SPIOF. The T2 signal intensity of U251 and C6 cells cultured with SPIOFC (233.6+/-25.9 and 211.4+/-17.2, respectively) were substantially lower than those of U251 and C6 cells incubated with SPIOF (2275.3+/-268.6 and 2342.7+/-222.4, respectively). Moreover, there were significant differences in iron per cell and T2 signal intensity between SPIOFC-treated neural cells (1.3+/-0.3; 2533.6+/-199.2) and SPIOFC-treated glioma cells. SPIOFC internalized by glioma cells exhibited green fluorescence by confocal laser scanning microscopy. CONCLUSION SPIOFC is suitable for the specific and efficient targeting of glioma cells. MRI and optical imaging in conjunction with SPIOFC can differentiate glioma cells from normal brain tissue cells.
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Affiliation(s)
- Xiang-xi Meng
- Department of Neurosurgery, First Affiliated Hospital, Harbin Medical University, Harbin 150001, China
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30
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Chapman GE, Ballinger JR, Norton MJ, Parry-Jones DR, Beharry NA, Cousins C, Dash CH, Peters AM. The clearance kinetics of autologous RhD-positive erythrocytes coated ex vivo with novel recombinant and monoclonal anti-D antibodies. Clin Exp Immunol 2007; 150:30-41. [PMID: 17680827 PMCID: PMC2219283 DOI: 10.1111/j.1365-2249.2007.03458.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Anti-D is given routinely to pregnant RhD-negative women to prevent haemolytic disease of the fetus and newborn. To overcome the potential drawbacks associated with plasma-derived products, monoclonal and recombinant forms of anti-D have been developed. The ability of two such antibodies, BRAD-3/5 monoclonal anti-D IgG (MAD) and rBRAD-3/5 recombinant anti-D IgG (RAD), to clear RhD-positive erythrocytes from the circulation was compared using a dual radiolabelling technique. Six RhD-positive males received autologous erythrocytes radiolabelled with (99m)Tc and (51)Cr and coated ex vivo with MAD and RAD. Blood samples were collected up to 1 h following intravenous injection, and percentage dose of radioactivity in the samples determined. Three different levels of coating were used on three separate occasions. No significant differences between MAD and RAD were observed in the initial clearance rate constant at any dose level. The log[activity]-time clearance plots were curved, showing a reduction in the clearance rate constant with time. This reduction was more marked for RAD than for MAD. The results support a dynamic model for the clearance of antibody-coated erythrocytes that may have wider relevance for the therapeutic use of antibodies.
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Affiliation(s)
- G E Chapman
- Bio Products Laboratory, Elstree, Hertfordshire, UK
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31
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Lee WL, Mason D, Schreiber AD, Grinstein S. Quantitative analysis of membrane remodeling at the phagocytic cup. Mol Biol Cell 2007; 18:2883-92. [PMID: 17507658 PMCID: PMC1949373 DOI: 10.1091/mbc.e06-05-0450] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Nascent phagosomes, which are derived from the plasma membrane, acquire microbicidal properties through multiple fusion and fission events collectively known as maturation. Here we show that remodeling of the phagosomal membrane is apparent even before sealing, particularly when large particles are ingested. Fluorescent probes targeted to the plasma membrane are cleared from the region lining the particle before engulfment is completed. Extensive clearance was noted for components of the inner as well as outer monolayer of the plasmalemma. Segregation of lipid microdomains was ruled out as the mechanism underlying membrane remodeling, because markers residing in rafts and those that are excluded were similarly depleted. Selective endocytosis was also ruled out. Instead, several lines of evidence indicate that endomembranes inserted by exocytosis at sites of ingestion displace the original membrane constituents from the base of the phagosomal cup. The Fcgamma receptors that trigger phagocytosis remain associated with their ligands. By contrast, Src-family kinases that are the immediate effectors of receptor activation are flushed away from the cup by the incoming membranes. Together with the depletion of phosphoinositides required for signal transduction, the disengagement of receptors from their effectors by bulk membrane remodeling provides a novel means to terminate receptor signaling.
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Affiliation(s)
- Warren L. Lee
- *Programme in Cell Biology, Hospital for Sick Children
- Interdepartmental Division of Critical Care Medicine, and
- the Division of Respirology, Department of Medicine, University of Toronto, Toronto, Ontario, M5G 1X8 Canada; and
| | - David Mason
- *Programme in Cell Biology, Hospital for Sick Children
| | - Alan D. Schreiber
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104
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Rodrigo WWSI, Jin X, Blackley SD, Rose RC, Schlesinger JJ. Differential enhancement of dengue virus immune complex infectivity mediated by signaling-competent and signaling-incompetent human Fcgamma RIA (CD64) or FcgammaRIIA (CD32). J Virol 2006; 80:10128-38. [PMID: 17005690 PMCID: PMC1617290 DOI: 10.1128/jvi.00792-06] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Fcgamma receptor (FcgammaR)-mediated entry of infectious dengue virus immune complexes into monocytes/macrophages is hypothesized to be a key event in the pathogenesis of complicated dengue fever. FcgammaRIA (CD64) and FcgammaRIIA (CD32), which predominate on the surface of such dengue virus-permissive cells, were compared for their influence on the infectivity of dengue 2 virus immune complexes formed with human dengue virus antibodies. A signaling immunoreceptor tyrosine-based activation motif (ITAM) incorporated into the accessory gamma-chain subunit that associates with FcgammaRIA and constitutively in FcgammaRIIA is required for phagocytosis mediated by these receptors. To determine whether FcgammaRIA and FcgammaRIIA activation functions are also required for internalization of infectious dengue virus immune complexes, we generated native and signaling-incompetent versions of each receptor by site-directed mutagenesis of ITAM tyrosine residues. Plasmids designed to express these receptors were transfected into COS-7 cells, and dengue virus replication was measured by plaque assay and flow cytometry. We found that both receptors mediated enhanced dengue virus immune complex infectivity but that FcgammaRIIA appeared to do so far more effectively. Abrogation of FcgammaRIA signaling competency, either by expression without gamma-chain or by coexpression with gamma-chain mutants, was associated with significant impairment of phagocytosis and of dengue virus immune complex infectivity. Abrogation of FcgammaRIIA signaling competency was also associated with equally impaired phagocytosis but had no discernible effect on dengue virus immune complex infectivity. These findings point to fundamental differences between FcgammaRIA and FcgammaRIIA with respect to their immune-enhancing capabilities and suggest that different mechanisms of dengue virus immune complex internalization may operate between these FcgammaRs.
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Affiliation(s)
- W W Shanaka I Rodrigo
- Division of Infectious Diseases, Department of Medicine, University of Rochester School of Medicine and Dentistry, Box 689, 601 Crittenden Avenue, Rochester, NY 14642, USA
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Suh CI, Stull ND, Li XJ, Tian W, Price MO, Grinstein S, Yaffe MB, Atkinson S, Dinauer MC. The phosphoinositide-binding protein p40phox activates the NADPH oxidase during FcgammaIIA receptor-induced phagocytosis. ACTA ACUST UNITED AC 2006; 203:1915-25. [PMID: 16880255 PMCID: PMC2118377 DOI: 10.1084/jem.20052085] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Superoxide produced by the phagocyte reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is essential for host defense. Enzyme activation requires translocation of p67phox, p47phox, and Rac-GTP to flavocytochrome b558 in phagocyte membranes. To examine the regulation of phagocytosis-induced superoxide production, flavocytochrome b558, p47phox, p67phox, and the FcγIIA receptor were expressed from stable transgenes in COS7 cells. The resulting COSphoxFcγR cells produce high levels of superoxide when stimulated with phorbol ester and efficiently ingest immunoglobulin (Ig)G-coated erythrocytes, but phagocytosis did not activate the NADPH oxidase. COS7 cells lack p40phox, whose role in the NADPH oxidase is poorly understood. p40phox contains SH3 and phagocyte oxidase and Bem1p (PB1) domains that can mediate binding to p47phox and p67phox, respectively, along with a PX domain that binds to phosphatidylinositol-3-phosphate (PI(3)P), which is generated in phagosomal membranes. Expression of p40phox was sufficient to activate superoxide production in COSphoxFcγR phagosomes. FcγIIA-stimulated NADPH oxidase activity was abrogated by point mutations in p40phox that disrupt PI(3)P binding, or by simultaneous mutations in the SH3 and PB1 domains. Consistent with an essential role for PI(3)P in regulating the oxidase complex, phagosome NADPH oxidase activation in primary macrophages ingesting IgG-coated beads was inhibited by phosphatidylinositol 3 kinase inhibitors to a much greater extent than phagocytosis itself. Hence, this study identifies a role for p40phox and PI(3)P in coupling FcγR-mediated phagocytosis to activation of the NADPH oxidase.
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Affiliation(s)
- Chang-Il Suh
- Department of Pediatrics (Hematology/Oncology), Herman B Wells Center for Pediatric Research, Riley Hospital for Children, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Cougoule C, Hoshino S, Dart A, Lim J, Caron E. Dissociation of recruitment and activation of the small G-protein Rac during Fcgamma receptor-mediated phagocytosis. J Biol Chem 2006; 281:8756-64. [PMID: 16434390 DOI: 10.1074/jbc.m513731200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Rho-family proteins play a central role in most actin-dependent processes, including the control and maintenance of cell shape, adhesion, motility, and phagocytosis. Activation of these GTP-binding proteins is tightly regulated spatially and temporally; however, very little is known of the mechanisms involved in their recruitment and activation in vivo. Because of its inducible, restricted signaling, phagocytosis offers an ideal physiological system to delineate the pathways linking surface receptors to actin remodeling via Rho GTPases. In this study, we investigated the involvement of early regulators of Fcgamma receptor signaling in Rac recruitment and activation. Using a combination of receptor mutagenesis, cellular, molecular, and pharmacological approaches, we show that Src family and Syk kinases control Rac and Vav function during phagocytosis. Importantly, both the immunoreceptor tyrosine-based activation motif within Fcgamma receptor cytoplasmic domain and Src kinase control the recruitment of Vav and Rac. However, Syk activity is dispensable for Vav and Rac recruitment. Moreover, we show that Rac and Cdc42 activities coordinate F-actin accumulation at nascent phagosomes. Our results provide new insights in the understanding of the spatiotemporal regulation of Rho-family GTPase function, and of Rac in particular, during phagocytosis. We believe they will contribute to a better understanding of more complex cellular processes, such as cell adhesion and migration.
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Affiliation(s)
- Céline Cougoule
- Centre for Molecular Microbiology and Infection, and Division of Cell and Molecular Cell biology, Faculty of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
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Sobota A, Strzelecka-Kiliszek A, Gładkowska E, Yoshida K, Mrozińska K, Kwiatkowska K. Binding of IgG-Opsonized Particles to FcγR Is an Active Stage of Phagocytosis That Involves Receptor Clustering and Phosphorylation. THE JOURNAL OF IMMUNOLOGY 2005; 175:4450-7. [PMID: 16177087 DOI: 10.4049/jimmunol.175.7.4450] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Fc gammaR mediate the phagocytosis of IgG-coated particles and the clearance of IgG immune complexes. By dissecting binding from internalization of the particles, we found that the binding stage, rather than particle internalization, triggered tyrosine phosphorylation of Fc gammaR and accompanying proteins. High amounts of Lyn kinase were found to associate with particles isolated at the binding stage from J774 cells. PP2 (4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine), an Src kinase inhibitor, but not piceatannol, an inhibitor of Syk kinase, reduced the amount of Lyn associated with the bound particles and simultaneously diminished the binding of IgG-coated particles. Studies of baby hamster kidney cells transfected with wild-type and mutant Fc gammaRIIA revealed that the ability of the receptor to bind particles was significantly reduced when phosphorylation of the receptor was abrogated by Y298F substitution in the receptor signaling motif. Under these conditions, binding of immune complexes of aggregated IgG was depressed to a lesser extent. A similar effect was exerted on the binding ability of wild-type Fc gammaRIIA by PP2. Moreover, expression of mutant kinase-inactive Lyn K275R inhibited both Fc gammaRIIA phosphorylation and IgG-opsonized particle binding. To gain insight into the mechanism by which protein tyrosine phosphorylation can control Fc gammaR-mediated binding, we investigated the efficiency of clustering of wild-type and Y298F-substituted Fc gammaRIIA upon binding of immune complexes. We found that a lack of Fc gammaRIIA phosphorylation led to an impairment of receptor clustering. The results indicate that phosphorylation of Fc gammaR and accompanying proteins, dependent on Src kinase activity, facilitates the clustering of activated receptors that is required for efficient particle binding.
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Affiliation(s)
- Andrzej Sobota
- Department of Cell Biology, Nencki Institute of Experimental Biology, Warsaw, Poland.
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36
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Peachman KK, Rao M, Palmer DR, Zidanic M, Sun W, Alving CR, Rothwell SW. Functional microtubules are required for antigen processing by macrophages and dendritic cells. Immunol Lett 2005; 95:13-24. [PMID: 15325793 DOI: 10.1016/j.imlet.2004.05.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2003] [Revised: 04/24/2004] [Accepted: 05/01/2004] [Indexed: 11/20/2022]
Abstract
Antigen-presenting cells readily phagocytose antigens and channel them through various membrane-bound organelles within the cell. In previous studies, we demonstrated that macrophages concentrated and localized particulate antigens to the trans-Golgi prior to displaying the MHC-class I-antigenic peptides on the cell surface. In this study, we evaluated the importance of cytoskeletal elements in the intracellular trafficking of soluble and liposome-encapsulated ovalbumin in murine bone marrow-derived macrophages and human dendritic cells. F-actin, as identified by staining with fluorescein phalloidin, was observed at the point of contact between soluble or liposomal antigen and the cell membrane, suggesting that a rearrangement of the cytoskeleton occurs to facilitate the uptake of the antigens. Cells were incubated with colchicine, a microtubule depolymerizing agent, or paclitaxel, a microtubule polymerizing agent, before the addition of Texas Red-labeled ovalbumin or liposome-encapsulated Texas Red-labeled ovalbumin. Colchicine disrupted the trans-Golgi, whereas the trans-Golgi complexes were intact in paclitaxel treated cells. In either paclitaxel or colchicine-treated macrophages, internalized liposomal ovalbumin was not concentrated in the area of the trans-Golgi as determined by staining with fluorescent ceramide. In contrast, soluble ovalbumin was concentrated in the region of the trans-Golgi in 15% of the dendritic cells treated with paclitaxel, whereas 6% of the dendritic cells were able to concentrate liposomal antigen. In colchicine-treated dendritic cells, both soluble and liposomal antigens were internalized but did not localize to the area of the trans-Golgi. These data suggest that trafficking of soluble and liposome-encapsulated ovalbumin requires a functional microtubule-dependent translocation system.
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Affiliation(s)
- Kristina K Peachman
- Department of Membrane Biochemistry, Division of Biochemistry, Walter Reed Army Institute of Research, 503 Robert Grant Road, Silver Spring, MD 20910-7500, USA.
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Bodman-Smith KB, Gregory RE, Harrison PT, Raynes JG. FcγRIIa expression with FcγRI results in C-reactive protein- and IgG-mediated phagocytosis. J Leukoc Biol 2004; 75:1029-35. [PMID: 15075346 DOI: 10.1189/jlb.0703306] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
C-reactive protein (CRP) is a pattern-recognition molecule, which can bind to phosphorylcholine and certain phosphorylated carbohydrates found on the surface of a number of microorganisms. CRP has been shown recently to bind human Fc receptor for immunoglobulin G (IgG; FcgammaR)I and mediate phagocytosis and signaling through the gamma-chain. To date, binding of monomeric CRP to FcgammaRII has been contentious. We demonstrate that erythrocytes opsonized with CRP bind FcgammaRIIa-transfected COS-7 cells. In addition, we demonstrate that FcgammaRI can use FcgammaRIIa R131 and H131 to phagocytose erythrocytes coated with IgG or purified or recombinant CRP in the absence of the gamma-chain. COS-7 cells expressing FcgammaRIIa or FcgammaRI alone did not phagocytose opsonized erythrocytes. Such phagocytosis required the cytoplasmic domain of FcgammaRIIa, as mutation of tyrosine at position 205 and truncation of the cytoplasmic domain from the end of the transmembrane region (position 206), resulting in the loss of the immunoreceptor tyrosine activatory motif, abrogated phagocytosis. FcgammaRIIa R131 was more efficient than FcgammaRIIa H131 at mediating CRP-dependent phagocytosis.
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38
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van Bruggen R, Anthony E, Fernandez-Borja M, Roos D. Continuous translocation of Rac2 and the NADPH oxidase component p67(phox) during phagocytosis. J Biol Chem 2004; 279:9097-102. [PMID: 14623873 DOI: 10.1074/jbc.m309284200] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In this study, the translocation of the NADPH oxidase components p67(phox) and Rac2 was studied during phagocytosis in living cells. For this purpose, green fluorescent protein (GFP)-tagged versions of these proteins were expressed in the myeloid cell line PLB-985. First, the correct localization of p67GFP and GFP-Rac2 was shown during phagocytosis of serum-treated zymosan by wild-type PLB-985 cells and PLB-985 X-CGD (chronic granulomatous disease) cells, which lack expression of flavocytochrome b(558). Subsequently, these constructs were used for fluorescence recovery after photobleaching studies to elucidate the turnover of these proteins on the phagosomal membrane. The turnover of p67GFP and GFP-Rac2 proved to be very high, indicating a continuous exchange of flavocytochrome b(558)-bound p67GFP and GFP-Rac2 for cytosolic, free p67GFP and GFP-Rac2. Furthermore, the importance of an intact actin cytoskeleton for correct localization of these proteins was investigated by disrupting the actin cytoskeleton with cytochalasin B. However, cytochalasin B treatment of PLB-985 cells did not alter the localization of p67GFP and GFP-Rac2 once phagocytosis was initiated. In addition, the continuous exchange of flavocytochrome b(558)-bound p67GFP and GFP-Rac2 for cytosolic p67GFP and GFP-Rac2 was still intact in cytochalasin B-treated cells, indicating that the translocation of these proteins does not depend on a rearrangement of the actin cytoskeleton.
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Affiliation(s)
- Robin van Bruggen
- Sanquin Research, and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, 1066 CX Amsterdam, The Netherlands
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McCaw SE, Schneider J, Liao EH, Zimmermann W, Gray-Owen SD. Immunoreceptor tyrosine-based activation motif phosphorylation during engulfment of Neisseria gonorrhoeae by the neutrophil-restricted CEACAM3 (CD66d) receptor. Mol Microbiol 2003; 49:623-37. [PMID: 12864848 DOI: 10.1046/j.1365-2958.2003.03591.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Gonorrhea is characterized by a purulent urethral or cervical discharge consisting primarily of neutrophils associated with Neisseria gonorrhoeae. These interactions are facilitated by gonococcal colony opacity-associated (Opa) protein binding to host cellular CEACAM receptors. Of these, CEACAM3 is restricted to neutrophils and contains an immunoreceptor tyrosine-based activation motif (ITAM) reminiscent of that found within certain phagocytic Fc receptors. CEACAM3 was tyrosine phosphorylated by a Src family kinase-dependent process upon infection by gonococci expressing CEACAM-specific Opa proteins. This phosphorylation was necessary for efficient bacterial uptake; however, a less efficient uptake process became evident when kinase inhibitors or mutagenesis of the ITAM were used to prevent phosphorylation. Ligated CEACAM3 was recruited to a cytoskeleton-containing fraction, intense foci of polymerized actin were evident where bacteria attached to HeLa-CEACAM3, and disruption of polymerized actin by cytochalasin D blocked all bacterial uptake by these cells. These data support a model whereby CEACAM3 can mediate the Opa-dependent uptake of N. gonorrhoeae via either an efficient, ITAM phosphorylation-dependent process that resembles phagocytosis or a less efficient, tyrosine phosphorylation-independent mechanism.
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Affiliation(s)
- Shannon E McCaw
- Department of Medical Genetics and Microbiology, University of Toronto, Toronto, Canada
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Di A, Nelson DJ, Bindokas V, Brown ME, Libunao F, Palfrey HC. Dynamin regulates focal exocytosis in phagocytosing macrophages. Mol Biol Cell 2003; 14:2016-28. [PMID: 12802072 PMCID: PMC165094 DOI: 10.1091/mbc.e02-09-0626] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Phagocytosis in macrophages is thought to involve insertion of cytoplasmic vesicles at sites of membrane expansion before particle ingestion ("focal" exocytosis). Capacitance (Cm) measurements of cell surface area were biphasic, with an initial rise indicative of exocytosis followed by a fall upon phagocytosis. Unlike other types of regulated exocytosis, the Cm rise was insensitive to intracellular Ca2+, but was inhibited by guanosine 5'-O-(2-thio)diphosphate. Particle uptake, but not Cm rise, was affected by phosphatidylinositol 3-kinase inhibitors. Inhibition of actin polymerization eliminated the Cm rise, suggesting possible coordination between actin polymerization and focal exocytosis. Introduction of anti-pan-dynamin IgG blocked Cm changes, suggesting that dynamin controls focal exocytosis and thereby phagocytosis. Similarly, recombinant glutathione S-transferase*amphiphysin-SH3 domain, but not a mutated form that cannot bind to dynamin, inhibited both focal exocytosis and phagocytosis. Immunochemical analysis of endogenous dynamin distribution in macrophages revealed a substantial particulate pool, some of which localized to a presumptive endosomal compartment. Expression of enhanced green fluorescent protein*dynamin-2 showed a motile dynamin pool, a fraction of which migrated toward and within the phagosomal cup. These results suggest that dynamin is involved in the production and/or movement of vesicles from an intracellular organelle to the cell surface to support membrane expansion around the engulfed particle.
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Affiliation(s)
- Anke Di
- Department of Neurobiology, Pharmacology, and Physiology, University of Chicago, Illinois 60637, USA
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41
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Capo C, Moynault A, Collette Y, Olive D, Brown EJ, Raoult D, Mege JL. Coxiella burnetii avoids macrophage phagocytosis by interfering with spatial distribution of complement receptor 3. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:4217-25. [PMID: 12682255 DOI: 10.4049/jimmunol.170.8.4217] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Phagocytosis is a highly localized event requiring the formation of spatially and temporally restricted signals. Numerous microorganisms have taken advantage of this property to invade host cells. Coxiella burnetii, the agent of Q fever, is an obligate intracellular bacterium that has developed a survival strategy in macrophages based on subversion of receptor-mediated phagocytosis. The uptake of C. burnetii is mediated by alpha(v)beta(3) integrin and is restricted by impaired cross-talk of alpha(v)beta(3) integrin and complement receptor 3 (CR3) (CD11b/CD18). In this study, we showed that CR3 molecules remained outside the pseudopodal extensions induced by C. burnetii in THP-1 monocytes, although alpha(v)beta(3) integrin was present in the pseudopods. Chemoattractants such as RANTES restored CR3 localization to the front of pseudopodal extensions and increased C. burnetii phagocytosis, demonstrating that the localization of CR3 is critical for bacterial uptake. In addition, monocyte activation due to the expression of HIV-1 Nef protein also restored CR3-mediated phagocytosis of C. burnetii by allowing CR3 redistribution toward bacterial-induced pseudopods. The redistribution of CR3 and increased C. burnetii phagocytosis in THP-1 cells stimulated by RANTES or expressing Nef were associated with the inhibition of intracellular replication of C. burnetii. Hence, the localization of CR3 is critical for bacterial phagocytosis and also for the control of bacterial replication. This study describes a nonpreviously reported strategy of phagocytosis subversion by intracellular pathogens based on altered localization of monocyte receptors.
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Affiliation(s)
- Christian Capo
- Unité des Rickettsies, Faculté de Médecine, Centre National de la Recherche Scientifique Unité Mixte de Recherche 6020, Marseille, France
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Abstract
Genomics and other high-throughput approaches, such as proteomics, are changing the way we study complex biological systems. In the past few years, these approaches have contributed markedly to improving our understanding of phagocytosis. Indeed, the ability to study biological systems by monitoring hundreds of proteins provides a level of resolution that is not attainable by the usual 'one protein at a time' approach. In this article, I discuss how proteomic approaches have revealed surprising findings that enable us to revisit established concepts, such as the origin of the phagosome membrane, and to propose new models of cell organization and the link between innate and adaptive immunity.
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Affiliation(s)
- Michel Desjardins
- Département de pathologie et biologie cellulaire, Université de Montréal and Caprion Pharmaceuticals, Montreal, Canada.
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43
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Berclaz PY, Zsengellér Z, Shibata Y, Otake K, Strasbaugh S, Whitsett JA, Trapnell BC. Endocytic internalization of adenovirus, nonspecific phagocytosis, and cytoskeletal organization are coordinately regulated in alveolar macrophages by GM-CSF and PU.1. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:6332-42. [PMID: 12444140 DOI: 10.4049/jimmunol.169.11.6332] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
GM-CSF gene-targeted (GM(-/-)) mice have impaired pulmonary clearance of bacterial and fungal pathogens by alveolar macrophages (AMs). Because AMs also clear adenovirus from the lung, the role of GM-CSF in endocytic internalization of adenovirus by AMs was evaluated. Pulmonary clearance of adenovirus was severely impaired in GM(-/-) mice compared to wild-type (GM(+/+)) mice as determined by Southern analysis of viral DNA. Internalization of adenovirus by AMs was deficient in GM(-/-) mice in vivo and in vitro as determined by uptake of fluorescently labeled adenovirus or by PCR quantification of adenoviral DNA internalized within AMs. An AM cell line previously established from GM(-/-) mice (mAM) had impaired internalization of adenovirus and transferrin-coated 100-nm latex beads compared to MH-S, a GM(+/+) AM cell line. Phagocytosis of 4- micro m latex beads was also impaired in mAM cells as determined by confocal and fluorescence microscopy. Retroviral vector-mediated reconstitution of PU.1 expression in cultured GM(-/-) AMs restored phagocytosis of 4- micro m beads, endocytosis of adenovirus, and transferrin-coated 100-nm beads (independent of integrin alpha(V) and transferrin receptors, respectively), and restored normal cytoskeletal organization, filamentous actin distribution, and stimulated formation of filopodia. Interestingly, mRNA for the phosphoinositide 3 kinase p110gamma isoform, important in macrophage phagocytic function, was absent in GM(-/-) AMs and was restored by PU.1 expression. These data show that GM-CSF, via PU.1, regulates endocytosis of small ( approximately 100 nm) pathogens/inert particles and phagocytosis of very large inert particles and suggests regulation of cytoskeletal organization by GM-CSF/PU.1 as the molecular basis of this control.
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Affiliation(s)
- Pierre-Yves Berclaz
- Division of Pulmonary Biology, Children's Hospital Medical Center, Cincinnati, OH 45229, USA
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Edberg JC, Qin H, Gibson AW, Yee AMF, Redecha PB, Indik ZK, Schreiber AD, Kimberly RP. The CY domain of the Fcgamma RIa alpha-chain (CD64) alters gamma-chain tyrosine-based signaling and phagocytosis. J Biol Chem 2002; 277:41287-93. [PMID: 12200451 DOI: 10.1074/jbc.m207835200] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although the cytoplasmic domain of the human FcgammaRIa alpha-chain lacks tyrosine-based phosphorylation motifs, it modulates receptor cycling and receptor-specific cytokine production. The cytoplasmic domain of FcgammaRIa is constitutively phosphorylated, and the inhibition of dephosphorylation with okadaic acid, an inhibitor of type 1 and type 2A protein serine/threonine phosphatase, inhibits both receptor-induced activation of the early tyrosine phosphorylation cascade and receptor-specific phagocytosis. To explore the basis for these effects of the cytoplasmic domain of FcgammaRIa, we developed a series of human FcgammaRIa molecular variants, expressed in the murine macrophage cell line P388D1, and demonstrate that serine phosphorylation of the cytoplasmic domain is an important regulatory mechanism. Truncation of the cytoplasmic domain and mutation of the cytoplasmic domain serine residues to alanine abolish the okadaic acid inhibition of phagocytic function. In contrast, the serine mutants did not recapitulate the selective effects of cytoplasmic domain truncation on cytokine production. These results demonstrate for the first time a direct functional role for serine phosphorylation in the alpha-chain of FcgammaRIa and suggest that the cytoplasmic domain of FcgammaRI regulates the different functional capacities of the FcgammaRIa-receptor complex.
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Affiliation(s)
- Jeffrey C Edberg
- Departments of Medicine and Microbiology, The University of Alabama at Birmingham, 1530 3rd Avenue S, THT433A, Birmingham, AL 35294, USA.
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Hirano S, Anuradha CD, Kanno S. krox-20/egr-2 is up-regulated following non-specific and homophilic adhesion in rat macrophages. Immunology 2002; 107:86-92. [PMID: 12225366 PMCID: PMC1782766 DOI: 10.1046/j.1365-2567.2002.01487.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Macrophages are known to adhere to a plastic dish via beta2 integrin (CR3) and scavenger receptors. Although their functions such as phagocytosis, endocytosis, and nitric oxide production have been investigated on adherent macrophages in vitro, very little is known about intracellular signals triggered by adhesion to a plastic dish. Recently we reported that the mRNA level of krox-20/egr-2 was significantly increased in rat alveolar macrophages following exposure to fibrous titanium dioxide particles. In the present study we report that up-regulation of krox-20/egr-2 gene expression following adhesion to a plastic dish and homophilic adhesion in rat alveolar macrophages and rat macrophage cell line, NR8383. The mRNA level of krox-20/egr-2 increased with a peak 1 hr after adhesion to a plastic dish in both cell types. Piceatannol inhibited tyrosine-phosphorylation of Syk and decreased both adhesion and krox-20/egr-2 mRNA level. In contrast staurosporine, a serine/threonine kinase inhibitor, increased adherence of macrophages and yet prohibited the adhesion-dependent increase in krox-20/egr-2 gene expression. When NR8383 cells are cultured in suspension, the cells aggregated naturally and produced cell clumps. The mRNA level of krox-20/egr-2 also increased in response to the homophilic intercellular adhesion. The increased mRNA level of krox-20/egr-2 was not caused by inflammatory stimuli, because lipopolysaccharide did not affect the aggregation-dependent up-regulation of krox-20/egr-2 gene. The up-regulation of krox-20/egr-2 gene due to the homophilic cell aggregation was also inhibited either by piceatannol or staurosporine. Those results suggest that krox-20/egr-2 gene expression is triggered by sensing non-specific and homophilic cellular adhesion and the following phosphorylation of signal transducing proteins including Syk and staurosporine-inhibitable kinases.
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Affiliation(s)
- Seishiro Hirano
- Environmental Health Sciences Division and Research Center for Environmental Risk, National Institute for Environmental Studies, Ibaraki, Japan.
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Tjia JS, Moghe PV. Regulation of cell motility on polymer substrates via "dynamic," cell internalizable, ligand microinterfaces. TISSUE ENGINEERING 2002; 8:247-61. [PMID: 12031114 DOI: 10.1089/107632702753725012] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In vivo, motile epidermal tissues frequently encounter ligand microinterfaces that are dynamic, owing to rapid cell-mediated substrate phagocytosis. In this study, we have examined cell motility phenomena in response to the adhesion ligand, collagen, which was presented on cell-internalizable 400-nm colloidal gold microcarriers. Normal human keratinocytes were seeded onto collagen-adsorbed poly(lactide-co-glycolide) (PLGA) films that were predeposited with varying densities of the ligand-associated microcarriers (LAMs), such that the overall ligand density and the ligand loading per microcarrier were invariant. Cells seeded on LAMs exhibited rapid and distinct cytoskeletal redistribution resulting in numerous filopodial extensions, indicative of activation of cell motility processes. We report that the population-averaged cell migration rate of cells, mu, was increased from 2 microm2/min on collagen substrates lacking the microcarriers, to approximately 50 microm2/min on collagen presenting LAMs. An increase in LAM density to 1.2 LAMs per microm2 was found to maximize mu, as well as the directional persistence and speed of cell migration, whereas very high LAM densities saturated cell internalization and diminished migration rates. The cell-LAM interactions essential to enhanced migration were ligand-activated, as mu; values were reduced 400% on internalizable microcarriers lacking ligands; moreover, cooperative ligand elicitation was possible, for example, when 10 microg/mL soluble fibronectin was introduced as a costimulant of keratinocytes, yielding the highest reported mu values (80 microm2/min) on collagen LAM-PLGA substrates. Notably, cell migration rates were severely repressed when cell internalization processes were challenged through covalent conjugation of ligand carriers to the substrate, indicating that signals from cell-LAM binding alone were inadequate for elevated levels of cell migration. Further analysis indicated that the presence of LAMs did not alter the protease-resistant adhesivity between the cell and the underlying substrate, suggesting that the activation governing ligand interactions likely arose at the cell-LAM interface rather than the cell-substrate interface. This study highlights the novel use of secondary ligand-presenting microscale/nanoscale depots at polymer substrates to elicit, via dynamic cell internalization processes, significantly enhanced levels of cell migration over traditional interfaces with ligand-bearing substrates.
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Affiliation(s)
- Jane S Tjia
- Department of Chemical and Biochemical Engineering, Rutgers University, Piscataway, New Jersey 08854, USA
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Zhang Y, Kohler N, Zhang M. Surface modification of superparamagnetic magnetite nanoparticles and their intracellular uptake. Biomaterials 2002; 23:1553-61. [PMID: 11922461 DOI: 10.1016/s0142-9612(01)00267-8] [Citation(s) in RCA: 1035] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Superparamagnetic magnetite nanoparticles were surface-modified with poly (ethylene glycol) (PEG) and folic acid, respectively, to improve their intracellular uptake and ability to target specific cells. PEG and folic acid were successfully immobilized on the surfaces of magnetite nanoparticles and characterized using fourier transform infrared spectra. The nanoparticle internalization into mouse macrophage (RAW 264.7) and human breast cancer (BT20) cells was visualized using both fluorescence and confocal microscopy, and quantified by inductively coupled plasma emission spectroscopy (ICP). After the cells were cultured for 48 h in the medium containing the nanoparticles modified with PEG or folic acid, the results of fluorescence and confocal microscopy showed that the nanoparticles were internalized into the cells. The ICP measurements indicated that the uptake amount of PEG-modified nanoparticles into macrophage cells was much lower than that of unmodified nanoparticles. while folic acid modification did not change the amount of the uptake. However, for breast cancer cells, both PEG and folic acid modification facilitated the nanoparticle internalization into the cells. Therefore, PEG and folic acid modification of magnetite nanoparticles could be used to resist the protein adsorption and thus avoid the particle recognition by macrophage cells, and to facilitate the nanoparticle uptake to specific cancer cells for cancer therapy and diagnosis.
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Affiliation(s)
- Yong Zhang
- Department of Materials Science & Engineering, University of Washington, Seattle 98195-2120, USA.
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48
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Billker O, Popp A, Brinkmann V, Wenig G, Schneider J, Caron E, Meyer TF. Distinct mechanisms of internalization of Neisseria gonorrhoeae by members of the CEACAM receptor family involving Rac1- and Cdc42-dependent and -independent pathways. EMBO J 2002; 21:560-71. [PMID: 11847104 PMCID: PMC125849 DOI: 10.1093/emboj/21.4.560] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2001] [Revised: 12/13/2001] [Accepted: 12/13/2001] [Indexed: 02/07/2023] Open
Abstract
Opa adhesins of pathogenic Neisseria species target four members of the human carcinoembryonic antigen-related cellular adhesion molecule (CEACAM) family. CEACAM receptors mediate opsonization-independent phagocytosis of Neisseria gonorrhoeae by human granulocytes and each receptor individually can mediate gonococcal invasion of epithelial cells. We show here that gonococcal internalization occurs by distinct mechanisms depending on the CEACAM receptor expressed. For the invasion of epithelial cell lines via CEACAM1 and CEACAM6, a pathogen-directed reorganization of the actin cytoskeleton is not required. In marked contrast, ligation of CEACAM3 triggers a dramatic but localized reorganization of the host cell surface leading to highly efficient engulfment of bacteria in a process regulated by the small GTPases Rac1 and Cdc42, but not Rho. Two tyrosine residues of a cytoplasmic immune receptor tyrosine-based activating motif of CEACAM3 are essential for the induction of phagocytic actin structures and subsequent gonococcal internalization. The granulocyte-specific CEACAM3 receptor has properties of a single chain phagocytic receptor and may thus contribute to innate immunity by the elimination of Neisseria and other CEACAM-binding pathogens that colonize human mucosal surfaces.
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Affiliation(s)
- Oliver Billker
- Max-Planck-Institut für Infektionsbiologie, Abteilung Molekulare Biologie, Schumannstrasse 21/22, D-10117 Berlin, Germany
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49
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Diakonova M, Bokoch G, Swanson JA. Dynamics of cytoskeletal proteins during Fcgamma receptor-mediated phagocytosis in macrophages. Mol Biol Cell 2002; 13:402-11. [PMID: 11854399 PMCID: PMC65636 DOI: 10.1091/mbc.01-05-0273] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Particle ingestion by phagocytosis results from sequential rearrangements of the actin cytoskeleton and overlying membrane. To assemble a chronology of molecular events during phagosome formation and to examine the contributions of phosphoinositide 3-kinase (PI 3-kinase) to these dynamics, a method was developed for synchronizing Fcgamma receptor-mediated phagocytosis by murine macrophages. Erythrocytes opsonized with complement component C3bi were bound to macrophages at 37degrees C, a condition that does not favor particle phagocytosis. Addition of soluble anti-erythrocyte IgG resulted in rapid opsonization of the bound erythrocytes, followed by their immediate internalization via phagocytosis. Cellular content of F-actin, as measured by binding of rhodamine-phalloidin, increased transiently during phagocytosis, and this increase was not diminished by inhibitors of PI 3-kinase. Immunofluorescence localization of myosins in macrophages fixed at various times during phagocytosis indicated that myosins II and IXb were concentrated in early phagosomes, myosin IC increased later, and myosin V appeared after phagosome closure. Other cytoskeletal proteins showed similar variations in the timing of their appearance in phagosomes. The PI 3-kinase inhibitor wortmannin did not change the dynamics of PI 3-kinase or ezrin localization but prevented the loss of PAK1 from phagosomes. These results suggest that PI 3-kinase deactivates PAK1, and that this may be needed for phagosome closure.
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Affiliation(s)
- Maria Diakonova
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109-0620, USA
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50
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Antonieta Cote-Vélez MJ, Ortega E, Ortega A. Involvement of pp125FAK and p60SRC in the signaling through Fc gamma RII-Fc gamma RIII in murine macrophages. Immunol Lett 2001; 78:189-94. [PMID: 11578694 DOI: 10.1016/s0165-2478(01)00251-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cross-linking the FcgammaRs can activate a wide variety of biological responses in macrophages. Receptor stimulation induces activation of protein tyrosine kinase cascades that result in phagocytosis, a process known to involve cytoskeletal rearrangements. Therefore, an involvement of non-receptor tyrosine kinases such as pp125FAK, in FcgammaR signaling is likely. Using the murine macrophage cell line J774, we demonstrate that FcgammaRII-RIII cross-linking induces a time- and dose-dependent increase in tyrosine phosphorylation of the focal adhesion kinase pp125FAK that correlates with an increase in its catalytic activity. Interestingly enough, pp125FAK activation results in its association both to the FcgammaRII-III and to p60Src. The results presented here define a novel-signaling pathway likely to be important in low affinity FcgammaRII-III mediated phagocytosis.
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Affiliation(s)
- M J Antonieta Cote-Vélez
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Apartado Postal 14-740, D.F. 07000, Mexico, Mexico
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