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Dahou S, Smahi MCE, Nouari W, Dahmani Z, Benmansour S, Ysmail-Dahlouk L, Miliani M, Yebdri F, Fakir N, Laoufi MY, Chaib-Draa M, Tourabi A, Aribi M. L-Threoascorbic acid treatment promotes S. aureus-infected primary human endothelial cells survival and function, as well as intracellular bacterial killing, and immunomodulates the release of IL-1β and soluble ICAM-1. Int Immunopharmacol 2021; 95:107476. [PMID: 33676147 DOI: 10.1016/j.intimp.2021.107476] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 12/16/2022]
Abstract
BACKGROUND Vitamin C (ascorbic acid, AscH2) has been shown to enhance immunity. Here, we studied its immunomodulatory effect on human endothelial cells (ECs) during S. aureus infection. MATERIALS AND METHODS The ex vivo effects of AscH2 were performed on primary human umbilical vein endothelial cells (HUVECs) infected or not with S. aureus. RESULTS AscH2 treatment induced a marked downregulation of nitric oxide (NO) production and a moderate upregulation of arginase activity in S. aureus-infected HUVECs (respectively, p < 0.05 and p > 0.05). Although the upregulated release levels of soluble intercellular adhesion molecular 1 (sICAM-1/sCD54) and sE-selectin (sCD62E) molecules were not significantly different between treated and untreated S. aureus-infected HUVECs, AscH2 treatment induced reversing effect on sICAM-1 release when comparing to uninfected control HUVECs. Moreover, AscH2 treatment appears to have a significant effect on preventing HUVEC necrosis induced by S. aureus infection (p < 0.05). Furthermore, AscH2 treatment induced a significant upregulation of cell protective redox biomarker in S. aureus-infected, as shown by superoxide dismutase (SOD) activity (p < 0.05), but not by catalase activity (p > 0.05). Additionally, S. aureus infection markedly downregulated total bound calcium ions (bCa2+) levels as compared to control HUVECs, whereas, AscH2 treatment induced a slight upregulation of bCa2+ levels in infected HUVECs as compared to infected and untreated HUVECs (p > 0.05). On the other hand, AscH2 treatment downregulated increased total cellular cholesterol content (tccCHOL) levels in HUVECs induced by S. aureus infection (p < 0.05). In addition, AscH2 treatment markedly reversed S. aureus effect on upregulation of intracellular glucose (iGLU) levels within infected HUVECs (p < 0.05). Moreover, AscH2 treatment significantly downregulated S. aureus growth (p < 0.05), and significantly upregulated bacterial internalization and intracellular killing by HUVECs (p < 0.05), as well as their cell cycle activation (p < 0.01). Finally, AscH2 treatment has a slight effect on the production of interleukin 6 (IL-6), but induced a marked downregulation of that of IL-1β in S. aureus-infected HUVECs (respectively, p > 0.05, and p < 0.05). CONCLUSIONS Our outcomes demonstrated that, during S. aureus infection, AscH2 treatment promotes human ECs survival and function, as well as prevents inflammatory response exacerbation, while inducing bactericidal activity.
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Affiliation(s)
- Sara Dahou
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria
| | - Mohammed Chems-Eddine Smahi
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria; Neonatal Department of Specialized Maternal and Child Hospital of Tlemcen, 13000, Tlemcen, Algeria
| | - Wafa Nouari
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria
| | - Zoheir Dahmani
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria
| | - Souheila Benmansour
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria; Neonatal Department of Specialized Maternal and Child Hospital of Tlemcen, 13000, Tlemcen, Algeria
| | - Lamia Ysmail-Dahlouk
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria
| | - Maroua Miliani
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria
| | - Fadela Yebdri
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria
| | - Nassima Fakir
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria
| | - Mohammed Yassine Laoufi
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria; Neonatal Department of Specialized Maternal and Child Hospital of Tlemcen, 13000, Tlemcen, Algeria
| | - Mouad Chaib-Draa
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria
| | - Amina Tourabi
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria
| | - Mourad Aribi
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria.
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2
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Mellergaard M, Høgh RI, Lund A, Aldana BI, Guérillot R, Møller SH, Hayes AS, Panagiotopoulou N, Frimand Z, Jepsen SD, Hansen CHF, Andresen L, Larsen AR, Peleg AY, Stinear TP, Howden BP, Waagepetersen HS, Frees D, Skov S. Staphylococcus aureus induces cell-surface expression of immune stimulatory NKG2D ligands on human monocytes. J Biol Chem 2020; 295:11803-11821. [PMID: 32605922 PMCID: PMC7450114 DOI: 10.1074/jbc.ra120.012673] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 06/24/2020] [Indexed: 12/24/2022] Open
Abstract
Staphylococcus aureus is among the leading causes of bacterial infections worldwide. The pathogenicity and establishment of S. aureus infections are tightly linked to its ability to modulate host immunity. Persistent infections are often associated with mutant staphylococcal strains that have decreased susceptibility to antibiotics; however, little is known about how these mutations influence bacterial interaction with the host immune system. Here, we discovered that clinical S. aureus isolates activate human monocytes, leading to cell-surface expression of immune stimulatory natural killer group 2D (NKG2D) ligands on the monocytes. We found that expression of the NKG2D ligand ULBP2 (UL16-binding protein 2) is associated with bacterial degradability and phagolysosomal activity. Moreover, S. aureus-induced ULBP2 expression was linked to altered host cell metabolism, including increased cytoplasmic (iso)citrate levels, reduced glycolytic flux, and functional mitochondrial activity. Interestingly, we found that the ability of S. aureus to induce ULBP2 and proinflammatory cytokines in human monocytes depends on a functional ClpP protease in S. aureus These findings indicate that S. aureus activates ULBP2 in human monocytes through immunometabolic mechanisms and reveal that clpP inactivation may function as a potential immune evasion mechanism. Our results provide critical insight into the interplay between the host immune system and S. aureus that has evolved under the dual selective pressure of host immune responses and antibiotic treatment. Our discovery of an immune stimulatory pathway consisting of human monocyte-based defense against S. aureus suggests that targeting the NKG2D pathway holds potential for managing persistent staphylococcal infections.
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Affiliation(s)
- Maiken Mellergaard
- Experimental Animal Models, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Rikke Illum Høgh
- Experimental Animal Models, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Astrid Lund
- Experimental Animal Models, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Blanca Irene Aldana
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Romain Guérillot
- Department of Microbiology and Immunology, University of Melbourne at the Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Sofie Hedlund Møller
- Experimental Animal Models, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ashleigh S Hayes
- Department of Microbiology and Immunology, University of Melbourne at the Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Nafsika Panagiotopoulou
- Experimental Animal Models, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Zofija Frimand
- Experimental Animal Models, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Stine Dam Jepsen
- Experimental Animal Models, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Camilla Hartmann Friis Hansen
- Experimental Animal Models, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lars Andresen
- Experimental Animal Models, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anders Rhod Larsen
- Statens Serum Institut, Microbiology and Infection Control, Copenhagen, Denmark
| | - Anton Y Peleg
- Department of Infectious Diseases, Alfred Hospital and Central Clinical School, Monash University, Melbourne, Victoria, Australia
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Timothy P Stinear
- Department of Microbiology and Immunology, University of Melbourne at the Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Benjamin P Howden
- Department of Microbiology and Immunology, University of Melbourne at the Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Helle S Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Dorte Frees
- Food Safety and Zoonosis, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Søren Skov
- Experimental Animal Models, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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3
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Kyrmizi I, Ferreira H, Carvalho A, Figueroa JAL, Zarmpas P, Cunha C, Akoumianaki T, Stylianou K, Deepe GS, Samonis G, Lacerda JF, Campos A, Kontoyiannis DP, Mihalopoulos N, Kwon-Chung KJ, El-Benna J, Valsecchi I, Beauvais A, Brakhage AA, Neves NM, Latge JP, Chamilos G. Calcium sequestration by fungal melanin inhibits calcium-calmodulin signalling to prevent LC3-associated phagocytosis. Nat Microbiol 2018; 3:791-803. [PMID: 29849062 DOI: 10.1038/s41564-018-0167-x] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 04/23/2018] [Indexed: 11/09/2022]
Abstract
LC3-associated phagocytosis (LAP) is a non-canonical autophagy pathway regulated by Rubicon, with an emerging role in immune homeostasis and antifungal host defence. Aspergillus cell wall melanin protects conidia (spores) from killing by phagocytes and promotes pathogenicity through blocking nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-dependent activation of LAP. However, the signalling regulating LAP upstream of Rubicon and the mechanism of melanin-induced inhibition of this pathway remain incompletely understood. Herein, we identify a Ca2+ signalling pathway that depends on intracellular Ca2+ sources from endoplasmic reticulum, endoplasmic reticulum-phagosome communication, Ca2+ release from phagosome lumen and calmodulin (CaM) recruitment, as a master regulator of Rubicon, the phagocyte NADPH oxidase NOX2 and other molecular components of LAP. Furthermore, we provide genetic evidence for the physiological importance of Ca2+-CaM signalling in aspergillosis. Finally, we demonstrate that Ca2+ sequestration by Aspergillus melanin inside the phagosome abrogates activation of Ca2+-CaM signalling to inhibit LAP. These findings reveal the important role of Ca2+-CaM signalling in antifungal immunity and identify an immunological function of Ca2+ binding by melanin pigments with broad physiological implications beyond fungal disease pathogenesis.
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Affiliation(s)
- Irene Kyrmizi
- Department of Medicine, University of Crete, Heraklion, Crete, Greece.,Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, Heraklion, Crete, Greece
| | - Helena Ferreira
- 3B's Research Group - Biomaterials, Biodegradables and Biomimetics, Guimarães, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Agostinho Carvalho
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.,Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, Braga, Portugal
| | - Julio Alberto Landero Figueroa
- Department of Chemistry, University of Cincinnati/Agilent Technologies Metallomics Center of the Americas, University of Cincinnati, Cincinnati, OH, USA
| | - Pavlos Zarmpas
- Department of Chemistry, University of Crete, Heraklion, Crete, Greece
| | - Cristina Cunha
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.,Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, Braga, Portugal
| | - Tonia Akoumianaki
- Department of Medicine, University of Crete, Heraklion, Crete, Greece
| | - Kostas Stylianou
- Department of Medicine, University of Crete, Heraklion, Crete, Greece
| | - George S Deepe
- Division of Infectious Diseases, College of Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - George Samonis
- Department of Medicine, University of Crete, Heraklion, Crete, Greece
| | - João F Lacerda
- Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Lisbon, Portugal.,Serviço de Hematologia e Transplantação de Medula, Hospital de Santa Maria, Lisbon, Portugal
| | - António Campos
- Serviço de Transplantação de Medula Óssea (STMO), Instituto Português de Oncologia do Porto, Porto, Portugal
| | - Dimitrios P Kontoyiannis
- Department of Infectious Diseases, The University of Texas, MD Anderson Cancer Center, Austin, TX, USA
| | | | - Kyung J Kwon-Chung
- Molecular Microbiology Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Jamel El-Benna
- INSERM-U1149, CNRS-ERL8252, Centre de Recherche sur l'Inflammation, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Laboratoire d'Excellence Inflamex, DHU FIRE, Faculté de Médecine, Site Xavier Bichat, Paris, France
| | | | - Anne Beauvais
- Unité des Aspergillus, Institut Pasteur, Paris, France
| | - Axel A Brakhage
- Department of Molecular and Applied Microbiology, Leibniz-Institute for Natural Product Research and Infection Biology (HKI) and Friedrich Schiller University, Jena, Germany
| | - Nuno M Neves
- 3B's Research Group - Biomaterials, Biodegradables and Biomimetics, Guimarães, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | | | - Georgios Chamilos
- Department of Medicine, University of Crete, Heraklion, Crete, Greece. .,Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, Heraklion, Crete, Greece.
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4
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Bierne H, Dramsi S, Gratacap MP, Randriamampita C, Carpenter G, Payrastre B, Cossart P. The invasion protein InIB from Listeria monocytogenes activates PLC-gamma1 downstream from PI 3-kinase. Cell Microbiol 2000; 2:465-76. [PMID: 11207601 DOI: 10.1046/j.1462-5822.2000.00069.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Entry of the bacterial pathogen Listeria monocytogenes into non-phagocytic mammalian cells is mainly mediated by the InlB protein. Here we show that in the human epithelial cell line HEp-2, the invasion protein InlB activates sequentially a p85beta-p110 class I(A) PI 3-kinase and the phospholipase C-gamma1 (PLC-gamma1) without detectable tyrosine phosphorylation of PLC-gamma1. Purified InlB stimulates association of PLC-gamma1 with one or more tyrosine-phosphorylated proteins, followed by a transient increase in intracellular inositol 1,4,5-trisphosphate (IP3) levels and a release of intracellular Ca2+ in a PI 3-kinase-dependent manner. Infection of HEp-2 cells with wild-type L. monocytogenes bacteria also induces association of PLC-gamma1 with phosphotyrosyl proteins. This interaction is undetectable upon infection with a deltainlB mutant revealing an InlB specific signal. Interestingly, pharmacological or genetic inactivation of PLC-gamma1 does not significantly affect InlB-mediated bacterial uptake, suggesting that InlB-mediated PLC-gamma1 activation and calcium mobilization are involved in post-internalization steps.
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Affiliation(s)
- H Bierne
- Unité des Interactions Bactéries-Cellules, Institut Pasteur, Paris, France
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5
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Zheng L, Zomerdijk TP, Van Den Barselaar MT, Geertsma MF, Van Furth R, Nibbering PH. Arachidonic acid, but not its metabolites, is essential for FcgammaR-stimulated intracellular killing of Staphylococcus aureus by human monocytes. Immunology 1999; 96:90-7. [PMID: 10233682 PMCID: PMC2326709 DOI: 10.1046/j.1365-2567.1999.00664.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Since arachidonic acid (AA) production by phospholipase A2 (PLA2) is essential for the Fcgamma receptor (FcgammaR)-mediated respiratory burst and phagocytosis of opsonized erythrocytes by monocytes and macrophages, we focused in this study on the role of AA and its metabolites in the FcgammaR-stimulated intracellular killing of Staphylococcus aureus by human monocytes. The results revealed that the PLA2 inhibitors, but not inhibitors of cyclo-oxygenase and lipoxygenase, markedly suppressed the FcgammaR-mediated killing process. The production of O-2 by monocytes upon FcgammaR cross-linking was inhibited by 4-bromophenacyl bromide in a dose-dependent fashion, indicating that inhibition of PLA2 activity impairs the oxygen-dependent bactericidal mechanisms of monocytes, which could be partially restored by addition of exogenous AA and docosahexaenoic acid, but not myristic acid. These polyunsaturated fatty acids, but not myristic acid, stimulated the intracellular killing of S. aureus by monocytes, although not as effectively as FcgammaR cross-linking. Furthermore, FcgammaR cross-linking stimulated the release of AA from monocytes. Studies with selective inhibitors revealed that the FcgammaR-mediated activation of PLA2 is dependent on Ca2+ and tyrosine kinase activity. Together these results indicate a key role for PLA2/AA, but not its major metabolites, in mediating the FcgammaR-stimulated intracellular killing of S. aureus by monocytes.
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Affiliation(s)
- L Zheng
- Department of Infectious Diseases, C5-P, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands
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6
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Zheng L, Nibbering PH, Zomerdijk TP, van Furth R. Protein tyrosine kinase activity is essential for Fc gamma receptor-mediated intracellular killing of Staphylococcus aureus by human monocytes. Infect Immun 1994; 62:4296-303. [PMID: 7927687 PMCID: PMC303108 DOI: 10.1128/iai.62.10.4296-4303.1994] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Our previous study revealed that the intracellular killing of Staphylococcus aureus by human monocytes after cross-linking Fc gamma receptor I (Fc gamma RI) or Fc gamma RII is a phospholipase C (PLC)-dependent process. The aim of the present study was to investigate whether protein tyrosine kinase (PTK) activity plays a role in the Fc gamma R-mediated intracellular killing of bacteria and activation of PLC in these cells. The results showed that phagocytosis of bacteria by monocytes was not affected by the PTK inhibitors genistein and tyrphostin-47. The intracellular killing of S. aureus by monocytes after cross-linking Fc gamma RII or Fc gamma RII with anti-Fc gamma R monoclonal antibody and a bridging antibody or with human immunoglobulin G (IgG) was inhibited by these compounds in a dose-dependent fashion. The production of O2- by monocytes after stimulation with IgG or IgG-opsonized S. aureus was almost completely blocked by the PTK inhibitor. These results indicate that inhibition of PTK impairs the oxygen-dependent bactericidal mechanisms of monocytes. Genistein and tyrphostin-47, which do not affect the enzymatic activity of purified PLC, prevented activation of PLC after cross-linking Fc gamma RI or Fc gamma RII, measured as an increase in the intracellular inositol 1,4,5-trisphosphate concentration. Cross-linking Fc gamma RI or Fc gamma RII induced rapid tyrosine phosphorylation of several proteins in monocytes, one of which was identified as PLC-gamma 1, and the phosphorylation could be completely blocked by PTK inhibitors, leading to the conclusion that activation of PLC after cross-linking Fc gamma R in monocytes is regulated by PTK activity. Together, these results demonstrate that PTK activity is essential for the activation of PLC which is involved in the Fc gamma R-mediated intracellular killing of S. aureus by human monocytes.
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Affiliation(s)
- L Zheng
- Department of Infectious Diseases, University Hospital, Leiden, The Netherlands
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7
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Casado JA, Merino J, Cid J, Subira ML, Sanchez-Ibarrola A. The type of interaction with Fc gamma R in human monocytes determines the efficiency of the generation of oxidative burst. Immunology 1994; 83:148-54. [PMID: 7821960 PMCID: PMC1415001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Receptors for the Fc fragment of IgG (Fc gamma R) have a well-documented role in the generation of oxidative burst. It is tempting to speculate that the type of interaction with Fc gamma R could be a mechanism of regulation of this process. Here we report on a comparative study of the induction of oxidative burst in human monocytes activated by means of different types of interaction with Fc gamma R. We studied non-primed monocytes obtained by centrifugal elutriation from healthy donors. These cells were submitted to Fc gamma R interactions following two distinct models: one, using particulate material (IgG-SRBC leading to phagocytosis or rosetting), and another using soluble reagents followed by cross-linking of the receptors (monoclonal antibodies against Fc gamma RI and Fc gamma RII and natural ligands, namely several isotypes of murine and human IgG). Phagocytosis and oxidative burst were studied simultaneously in the monocytes, following the methodology described recently. Human non-primed monocytes were able to generate a very obvious oxidative burst response after activation of Fc gamma R by particulate material. The same response was observed when Fc gamma RII was blocked by monoclonal antibodies. Ingestion was not necessary for activation of the oxidative burst, since the model of rosetting induced a level of burst generation similar to the one obtained in the phagocytic process. Cross-linking of Fc gamma RI by soluble reagents induced production of reactive oxidative intermediates (ROI) only when the ligand-binding site of the receptor was involved. These data lead to the conclusion that Fc gamma R interaction with soluble or particulate material induces oxidative burst in non-primed human monocytes only when the binding site of natural ligands is involved. The type of interaction also determines the efficiency of the generation of ROI. This fact could represent a regulatory mechanism.
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Affiliation(s)
- J A Casado
- Department of Immunology, Faculty of Medicine, University of Navarra, Pamplona, Spain
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8
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Zheng L, Nibbering PH, van Furth R. Stimulation of the intracellular killing of Staphylococcus aureus by human monocytes mediated by Fc gamma receptors I and II. Eur J Immunol 1993; 23:2826-33. [PMID: 8223859 DOI: 10.1002/eji.1830231116] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Previous studies have shown that intracellular killing of bacteria by monocytes is stimulated by interaction between IgG and Fc gamma receptors (Fc gamma R) in the membrane of these cells. In the present study anti-Fc gamma R monoclonal antibodies (mAb) were used to investigate the relative contributions of the various classes of Fc gamma R to the intracellular killing of Staphylococcus aureus by human monocytes and the biochemical pathways involved. Anti-Fc gamma RI or anti-Fc gamma RII mAb, but not anti-Fc gamma RIII mAb, efficiently stimulated the intracellular killing of bacteria by monocytes. Cross-linking Fc gamma RI or Fc gamma RII, but not Fc gamma RIII, on monocytes with mouse anti-Fc gamma R mAb followed by bridging with F(ab')2 fragments of goat anti-mouse IgG enhanced this process. Since the NADPH oxidase inhibitor diphenyleneiodonium blocked the Fc gamma R-mediated intracellular killing of S. aureus, oxygen-dependent bactericidal mechanisms are most probably involved. Cross-linking Fc gamma RI or Fc gamma RII but not binding of the mAb to the Fc gamma R on monocytes activated phospholipase C, as demonstrated by the increase in the intracellular concentration of inositol-(1,4,5)-triphosphate. The enhanced intracellular killing stimulated by cross-linking Fc gamma R on monocytes was completely blocked by U-73122, an inhibitor of phospholipase C-dependent processes. Protein kinase C activity, but not the rise in the cytosolic free Ca++ concentration or pertussis toxin-sensitive G proteins, is essential for the Fc gamma R-mediated intracellular killing of bacteria by monocytes. Together, these results demonstrate that cross-linking Fc gamma RI or Fc gamma RII is equally effective in stimulating the intracellular killing of bacteria by monocytes and that this stimulation is a phospholipase C-dependent process.
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Affiliation(s)
- L Zheng
- Department of Infectious Diseases, University Hospital, Leiden, The Netherlands
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9
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Majeed M, Gustafsson M, Kihlström E, Stendahl O. Roles of Ca2+ and F-actin in intracellular aggregation of Chlamydia trachomatis in eucaryotic cells. Infect Immun 1993; 61:1406-14. [PMID: 8454343 PMCID: PMC281378 DOI: 10.1128/iai.61.4.1406-1414.1993] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The effect of intracellular free Ca2+ ([Ca2+]i) on the intracellular aggregation of Chlamydia trachomatis serovars L2 and E in McCoy and HeLa cells is investigated. Loading the cells with the Ca2+ chelator MAPT/AM (1,2-bis-5-methyl-amino-phenoxylethane-N,N-n'-tetra-acetoxymethyl acetate), thereby decreasing the [Ca2+]i from 67 to 19 nM, decreased the number of cells with a local aggregation of chlamydiae in a dose-dependent manner. Neither the attachment nor the uptake of elementary bodies (EBs) was, however, affected after depletion of Ca2+ from the cells. There was no significant difference in the level of measured [Ca2+]i between infected and uninfected cells. Reducing the [Ca2+]i also significantly inhibited chlamydial inclusion formation. Differences in the organization of the actin filament network were observed in response to [Ca2+]i depletion. In Ca(2+)-depleted cells, where few EB aggregates were formed, few local accumulations of F-actin were observed in the cytosol. These results suggest that the aggregation of EBs in eucaryotic cells requires a normal homeostasis of intracellular Ca2+. By affecting F-actin reorganization and putatively certain Ca(2+)-binding proteins, [Ca2+]i plays a vital role in the infectious process of chlamydiae.
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Affiliation(s)
- M Majeed
- Department of Clinical Microbiology, University of Linköping, Sweden
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