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Alternative activation of macrophages by IL-4 impairs phagocytosis of pathogens but potentiates microbial-induced signalling and cytokine secretion. Blood 2009; 115:353-62. [PMID: 19880493 DOI: 10.1182/blood-2009-08-236711] [Citation(s) in RCA: 143] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Alternatively activated macrophages play an important role in host defense in the context of a T helper type 2 (Th2) microenvironment such as parasitic infection. However, the role of these macrophages during secondary challenge with Th1 pathogens is poorly defined. In this study, thioglycollate-elicited mouse peritoneal macrophages were treated with interleukin-4 (IL-4) or IL-13 in vitro and challenged with Neisseria meningitidis. After 8 to 12 hours of IL-4 pretreatment, the nonopsonic phagocytic uptake of N meningitidis was markedly reduced, depending on the common IL-4Ralpha chain, but independent of Scavenger receptor A and macrophage receptor with collagenous structure (MARCO), 2 known receptors for N meningitidis. Inhibition of phagocytosis extended to several other microbial particles, zymosan, and other bacteria. Concomitantly, IL-4 potentiated the secretion of proinflammatory cytokines, after additional bacterial stimulation, which depended on the MyD88 signaling pathway. Similar results were obtained after intraperitoneal stimulation of IL-4 and N meningitidis in vivo. Further in vitro studies showed a striking correlation with inhibition of Akt phosphorylation and stimulation of the mitogen-activated protein kinase pathway; inhibition of phagocytosis was associated with inhibition of phagosome formation. These findings are relevant to host defense in mixed infections within a Th2 microenvironment and shed light on immunologic functions associated with alternative priming and full activation of macrophages.
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Helming L, Tomasello E, Kyriakides TR, Martinez FO, Takai T, Gordon S, Vivier E. Essential role of DAP12 signaling in macrophage programming into a fusion-competent state. Sci Signal 2008; 1:ra11. [PMID: 18957693 DOI: 10.1126/scisignal.1159665] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Multinucleated giant cells, formed by fusion of macrophages, are a hallmark of granulomatous inflammation. With a genetic approach, we show that signaling through the adaptor protein DAP12 (DNAX activating protein of 12 kD), its associated receptor triggering receptor expressed by myeloid cells 2 (TREM-2), and the downstream protein tyrosine kinase Syk is required for the cytokine-induced formation of giant cells and that overexpression of DAP12 potentiates macrophage fusion. We also present evidence that DAP12 is a general macrophage fusion regulator and is involved in modulating the expression of several macrophage-associated genes, including those encoding known mediators of macrophage fusion, such as DC-STAMP and Cadherin 1. Thus, DAP12 is involved in programming of macrophages through the regulation of gene and protein expression to induce a fusion-competent state.
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Affiliation(s)
- Laura Helming
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
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Plüddemann A, Mukhopadhyay S, Sankala M, Savino S, Pizza M, Rappuoli R, Tryggvason K, Gordon S. SR-A, MARCO and TLRs differentially recognise selected surface proteins from Neisseria meningitidis: an example of fine specificity in microbial ligand recognition by innate immune receptors. J Innate Immun 2008; 1:153-63. [PMID: 20375573 DOI: 10.1159/000155227] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Accepted: 06/23/2008] [Indexed: 12/12/2022] Open
Abstract
Macrophages express various classes of pattern recognition receptors involved in innate immune recognition of artificial, microbial and host-derived ligands. These include the scavenger receptors (SRs), which are important for phagocytosis, and the Toll-like receptors (TLRs) involved in microbe sensing. The class A macrophage scavenger receptor (SR-A) and macrophage receptor with a collagenous structure (MARCO) display similar domain structures and ligand-binding specificity, which has led to the assumption that these two receptors may be functionally redundant. In this study we show that SR-A and MARCO differentially recognise artificial polyanionic ligands as well as surface proteins from the pathogenic bacterium Neisseria meningitidis. We show that, while acetylated low-density lipoprotein (AcLDL) is a strong ligand for SR-A, it is not a ligand for MARCO. Of the neisserial proteins that were SR ligands, some were ligands for both receptors, while other proteins were only recognised by either SR-A or MARCO. We also analysed the potential of these ligands to act as TLR agonists and assessed the requirement for SR-A and MARCO in pro-inflammatory cytokine induction. SR ligation alone did not induce cytokine production; however, for proteins that were both SR and TLR ligands, the SRs were required for full activation of TLR pathways.
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56
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Sulahian TH, Imrich A, Deloid G, Winkler AR, Kobzik L. Signaling pathways required for macrophage scavenger receptor-mediated phagocytosis: analysis by scanning cytometry. Respir Res 2008; 9:59. [PMID: 18687123 PMCID: PMC2527561 DOI: 10.1186/1465-9921-9-59] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2008] [Accepted: 08/07/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Scavenger receptors are important components of the innate immune system in the lung, allowing alveolar macrophages to bind and phagocytose numerous unopsonized targets. Mice with genetic deletions of scavenger receptors, such as SR-A and MARCO, are susceptible to infection or inflammation from inhaled pathogens or dusts. However, the signaling pathways required for scavenger receptor-mediated phagocytosis of unopsonized particles have not been characterized. METHODS We developed a scanning cytometry-based high-throughput assay of macrophage phagocytosis that quantitates bound and internalized unopsonized latex beads. This assay allowed the testing of a panel of signaling inhibitors which have previously been shown to target opsonin-dependent phagocytosis for their effect on unopsonized bead uptake by human in vitro-derived alveolar macrophage-like cells. The non-selective scavenger receptor inhibitor poly(I) and the actin destabilizer cytochalasin D were used to validate the assay and caused near complete abrogation of bead binding and internalization, respectively. RESULTS Microtubule destabilization using nocodazole dramatically inhibited bead internalization. Internalization was also significantly reduced by inhibitors of tyrosine kinases (genistein and herbimycin A), protein kinase C (staurosporine, chelerythrine chloride and Gö 6976), phosphoinositide-3 kinase (LY294002 and wortmannin), and the JNK and ERK pathways. In contrast, inhibition of phospholipase C by U-73122 had no effect. CONCLUSION These data indicate the utility of scanning cytometry for the analysis of phagocytosis and that phagocytosis of unopsonized particles has both shared and distinct features when compared to opsonin-mediated phagocytosis.
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Affiliation(s)
- Timothy H Sulahian
- Harvard School of Public Health, Molecular and Integrative Physiological Sciences Program, 655 Huntington Ave, Building II, 2nd Floor, Boston, MA 02115, USA.
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59
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Dahl M, Bauer AK, Arredouani M, Soininen R, Tryggvason K, Kleeberger SR, Kobzik L. Protection against inhaled oxidants through scavenging of oxidized lipids by macrophage receptors MARCO and SR-AI/II. J Clin Invest 2007; 117:757-64. [PMID: 17332894 PMCID: PMC1804372 DOI: 10.1172/jci29968] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2006] [Accepted: 12/12/2006] [Indexed: 01/27/2023] Open
Abstract
Alveolar macrophages (AMs) express the class A scavenger receptors (SRAs) macrophage receptor with collagenous structure (MARCO) and scavenger receptor AI/II (SRA-I/II), which recognize oxidized lipids and provide innate defense against inhaled pathogens and particles. Increased MARCO expression in lungs of ozone-resistant mice suggested an additional role protecting against inhaled oxidants. After ozone exposure, MARCO-/- mice showed greater lung injury than did MARCO+/+ mice. Ozone is known to generate oxidized, proinflammatory lipids in lung lining fluid, such as 5beta,6beta-epoxycholesterol (beta-epoxide) and 1-palmitoyl-2-(9'-oxo-nonanoyl)-glycerophosphocholine (PON-GPC). Intratracheal instillation of either lipid caused substantial neutrophil influx in MARCO-/- mice, but had no effect in MARCO+/+ mice. Normal AMs showed greater uptake in vitro of beta-epoxide compared with MARCO-/- AMs, consistent with SRA function in binding oxidized lipids. SR-AI/II-/- mice showed similar enhanced acute lung inflammation after beta-epoxide or another inhaled oxidant (aerosolized leachate of residual oil fly ash). In contrast, subacute ozone exposure did not enhance inflammation in SR-AI/II-/- versus SR-AI/II+/+ mice, reflecting increased AM expression of MARCO. These data identify what we believe to be a novel function for AM SRAs in decreasing pulmonary inflammation after oxidant inhalation by scavenging proinflammatory oxidized lipids from lung lining fluids.
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Affiliation(s)
- Morten Dahl
- Department of Environmental Health, Harvard School of Public Health, Harvard Medical School, Boston, Massachusetts, USA.
Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, North Carolina, USA.
Department of Medical Biochemistry and Molecular Biology, Biocenter Oulu, University of Oulu, Oulu, Finland.
Division of Matrix Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Alison K. Bauer
- Department of Environmental Health, Harvard School of Public Health, Harvard Medical School, Boston, Massachusetts, USA.
Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, North Carolina, USA.
Department of Medical Biochemistry and Molecular Biology, Biocenter Oulu, University of Oulu, Oulu, Finland.
Division of Matrix Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Mohamed Arredouani
- Department of Environmental Health, Harvard School of Public Health, Harvard Medical School, Boston, Massachusetts, USA.
Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, North Carolina, USA.
Department of Medical Biochemistry and Molecular Biology, Biocenter Oulu, University of Oulu, Oulu, Finland.
Division of Matrix Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Raija Soininen
- Department of Environmental Health, Harvard School of Public Health, Harvard Medical School, Boston, Massachusetts, USA.
Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, North Carolina, USA.
Department of Medical Biochemistry and Molecular Biology, Biocenter Oulu, University of Oulu, Oulu, Finland.
Division of Matrix Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Karl Tryggvason
- Department of Environmental Health, Harvard School of Public Health, Harvard Medical School, Boston, Massachusetts, USA.
Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, North Carolina, USA.
Department of Medical Biochemistry and Molecular Biology, Biocenter Oulu, University of Oulu, Oulu, Finland.
Division of Matrix Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Steven R. Kleeberger
- Department of Environmental Health, Harvard School of Public Health, Harvard Medical School, Boston, Massachusetts, USA.
Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, North Carolina, USA.
Department of Medical Biochemistry and Molecular Biology, Biocenter Oulu, University of Oulu, Oulu, Finland.
Division of Matrix Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Lester Kobzik
- Department of Environmental Health, Harvard School of Public Health, Harvard Medical School, Boston, Massachusetts, USA.
Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, North Carolina, USA.
Department of Medical Biochemistry and Molecular Biology, Biocenter Oulu, University of Oulu, Oulu, Finland.
Division of Matrix Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
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Farina C, Aloisi F, Meinl E. Astrocytes are active players in cerebral innate immunity. Trends Immunol 2007; 28:138-45. [PMID: 17276138 DOI: 10.1016/j.it.2007.01.005] [Citation(s) in RCA: 944] [Impact Index Per Article: 55.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Revised: 01/02/2007] [Accepted: 01/19/2007] [Indexed: 02/06/2023]
Abstract
Innate immunity is a constitutive component of the central nervous system (CNS) and relies strongly on resident myeloid cells, the microglia. However, evidence is emerging that the most abundant glial cell population of the CNS, the astrocyte, participates in the local innate immune response triggered by a variety of insults. Astrocytes display an array of receptors involved in innate immunity, including Toll-like receptors, nucleotide-binding oligomerization domains, double-stranded RNA-dependent protein kinase, scavenger receptors, mannose receptor and components of the complement system. Following activation, astrocytes are endowed with the ability to secrete soluble mediators, such as CXCL10, CCL2, interleukin-6 and BAFF, which have an impact on both innate and adaptive immune responses. The role of astrocytes in inflammation and tissue repair is elaborated by recent in vivo studies employing cell-type specific gene targeting.
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Affiliation(s)
- Cinthia Farina
- Neuroimmunology and Neuromuscular Disorders Unit, National Neurological Institute Carlo Besta, 20133 Milan, Italy.
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Steiniger B, Timphus EM, Barth PJ. The splenic marginal zone in humans and rodents: an enigmatic compartment and its inhabitants. Histochem Cell Biol 2006; 126:641-8. [PMID: 16816939 DOI: 10.1007/s00418-006-0210-5] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/06/2006] [Indexed: 01/04/2023]
Abstract
The role of the spleen in B memory cell development and maintenance is attracting increased attention. Studies in mice and rats have indicated that memory functions are associated with large B cells residing in the marginal zone (MZ) of the spleen. Although the cellular composition of the MZ is relatively well known in these species, controversies exist about the function of MZ B cells, their dependence on the presence of the spleen and the stage at which their development branches from that of recirculating follicular B cells. Additional confusion has arisen with respect to MZ B cells in humans, because the microscopic anatomy of the human splenic MZ differs decisively from that of rodents. Several recent publications indicate that the functional and migratory properties of human MZ B cells may be species-specific. The hypothesis derived from these publications and from our immunohistological observations implies that at least a major number of human splenic CD27(+) MZ B cells are migratory. Phenotypic data suggest a recirculation pathway between the spleen and mucosal tissues in humans.
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Affiliation(s)
- Birte Steiniger
- Institute of Anatomy and Cell Biology, University of Marburg, Robert-Koch-Str. 8, 35037 Marburg, Germany.
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