1
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Molitor DCA, Boor P, Buness A, Schneider RK, Teichmann LL, Körber RM, Horvath GL, Koschmieder S, Gütgemann I. Macrophage frequency in the bone marrow correlates with morphologic subtype of myeloproliferative neoplasm. Ann Hematol 2020; 100:97-104. [PMID: 33104881 PMCID: PMC7782416 DOI: 10.1007/s00277-020-04304-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 10/15/2020] [Indexed: 11/25/2022]
Abstract
Bone marrow (BM) fibrosis in myeloproliferative neoplasms (MPNs) is associated with a poor prognosis. The development of myelofibrosis and differentiation of mesenchymal stromal cells to profibrotic myofibroblasts depends on macrophages. Here, we compared macrophage frequencies in BM biopsies of MPN patients and controls (patients with non-neoplastic processes), including primary myelofibrosis (PMF, n = 18), essential thrombocythemia (ET, n = 14), polycythemia vera (PV, n = 12), and Philadelphia chromosome-positive chronic myeloid leukemia (CML, n = 9). In PMF, CD68-positive macrophages were greatly increased compared to CML (p = 0.017) and control BM (p < 0.001). Similar findings were observed by CD163 staining (PMF vs. CML: p = 0.017; PMF vs. control: p < 0.001). Moreover, CD68-positive macrophages were increased in PV compared with ET (p = 0.009) and reactive cases (p < 0.001). PMF had higher frequencies of macrophages than PV (CD68: p < 0.001; CD163: p < 0.001) and ET (CD68: p < 0.001; CD163: p < 0.001). CD163 and CD68 were often co-expressed in macrophages with stellate morphology in Philadelphia chromosome-negative MPN, resulting in a sponge-like reticular network that may be a key regulator of unbalanced hematopoiesis in the BM space and may explain differences in cellularity and clinical course.
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Affiliation(s)
| | - Peter Boor
- Institute of Pathology, University Hospital Aachen, RWTH Aachen, Bonn, Germany
| | - Andreas Buness
- Institute for Medical Biometry, Informatics and Epidemiology, Medical Faculty, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany.,Institute for Genomic Statistics and Bioinformatics, Medical Faculty, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Rebekka K Schneider
- Department of Hematology, Erasmus MC Cancer Center, Rotterdam, Netherlands.,Institute for Biomedical Engineering Department of Cell Biology , RWTH , Aachen, Germany
| | - Lino L Teichmann
- Department of Hematology and Oncology, University Hospital Bonn, Bonn, Germany
| | - Ruth-Miriam Körber
- Department of Hematology and Oncology, University Hospital Bonn, Bonn, Germany
| | - Gabor L Horvath
- Medical Faculty, Microscopy Core Facility, University of Bonn, Bonn, Germany
| | - Steffen Koschmieder
- Department of Hematology, Oncology, Hemostaseology, and Stem Cell Transplantation, Faculty of Medicine, RWTH Aachen, Aachen, Germany
| | - Ines Gütgemann
- Institute of Pathology, University Hospital Bonn, Bonn, Germany.
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2
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Stutz A, Kolbe CC, Stahl R, Horvath GL, Franklin BS, van Ray O, Brinkschulte R, Geyer M, Meissner F, Latz E. NLRP3 inflammasome assembly is regulated by phosphorylation of the pyrin domain. J Exp Med 2017; 214:1725-1736. [PMID: 28465465 PMCID: PMC5460996 DOI: 10.1084/jem.20160933] [Citation(s) in RCA: 226] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Revised: 02/09/2017] [Accepted: 03/17/2017] [Indexed: 02/03/2023] Open
Abstract
NLRP3 is an innate immune receptor that needs to be tightly regulated to prevent overshooting immune responses. Stutz et al. demonstrate that NLRP3 is phosphorylated as a safeguard against accidental activation, and that dephosphorylation involving PP2A activity is required for NLRP3 activation. NLRP3 is a cytosolic pattern recognition receptor that senses microbes and endogenous danger signals. Upon activation, NLRP3 forms an inflammasome with the adapter ASC, resulting in caspase-1 activation, release of proinflammatory cytokines and cell death. How NLRP3 activation is regulated by transcriptional and posttranslational mechanisms to prevent aberrant activation remains incompletely understood. Here, we identify three conserved phosphorylation sites in NLRP3 and demonstrate that NLRP3 activation is controlled by phosphorylation of its pyrin domain (PYD). Phosphomimetic residues in NLRP3 PYD abrogate inflammasome activation and structural modeling indicates that phosphorylation of the PYD regulates charge–charge interaction between two PYDs that are essential for NLRP3 activation. Phosphatase 2A (PP2A) inhibition or knock-down drastically reduces NLRP3 activation, showing that PP2A can license inflammasome assembly via dephosphorylating NLRP3 PYD. These results propose that the balance between kinases and phosphatases acting on the NLRP3 PYD is critical for NLRP3 activation.
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Affiliation(s)
- Andrea Stutz
- Institute of Innate Immunity, University Hospital, University of Bonn, 53127 Bonn, Germany
| | - Carl-Christian Kolbe
- Institute of Innate Immunity, University Hospital, University of Bonn, 53127 Bonn, Germany
| | - Rainer Stahl
- Institute of Innate Immunity, University Hospital, University of Bonn, 53127 Bonn, Germany
| | - Gabor L Horvath
- Institute of Innate Immunity, University Hospital, University of Bonn, 53127 Bonn, Germany
| | - Bernardo S Franklin
- Institute of Innate Immunity, University Hospital, University of Bonn, 53127 Bonn, Germany
| | - Olivia van Ray
- Institute of Innate Immunity, University Hospital, University of Bonn, 53127 Bonn, Germany
| | - Rebecca Brinkschulte
- Institute of Innate Immunity, University Hospital, University of Bonn, 53127 Bonn, Germany.,Center of Advanced European Studies and Research, 53175 Bonn, Germany
| | - Matthias Geyer
- Institute of Innate Immunity, University Hospital, University of Bonn, 53127 Bonn, Germany.,Center of Advanced European Studies and Research, 53175 Bonn, Germany
| | - Felix Meissner
- Experimental Systems Immunology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Eicke Latz
- Institute of Innate Immunity, University Hospital, University of Bonn, 53127 Bonn, Germany .,Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01655.,Deutsches Zentrum für Neurodegenerative Erkrankungen, 53175 Bonn, Germany.,Centre for Inflammation Research, Norwegian University of Science and Technology, 7491 Trondheim, Norway
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3
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Bertheloot D, Naumovski AL, Langhoff P, Horvath GL, Jin T, Xiao TS, Garbi N, Agrawal S, Kolbeck R, Latz E. RAGE Enhances TLR Responses through Binding and Internalization of RNA. J Immunol 2016; 197:4118-4126. [PMID: 27798148 DOI: 10.4049/jimmunol.1502169] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 09/20/2016] [Indexed: 01/08/2023]
Abstract
Nucleic acid recognition is an important mechanism that enables the innate immune system to detect microbial infection and tissue damage. To minimize the recognition of self-derived nucleic acids, all nucleic acid-sensing signaling receptors are sequestered away from the cell surface and are activated in the cytoplasm or in endosomes. Nucleic acid sensing in endosomes relies on members of the TLR family. The receptor for advanced glycation end-products (RAGE) was recently shown to bind DNA at the cell surface, facilitating DNA internalization and subsequent recognition by TLR9. In this article, we show that RAGE binds RNA molecules in a sequence-independent manner and enhances cellular RNA uptake into endosomes. Gain- and loss-of-function studies demonstrate that RAGE increases the sensitivity of all ssRNA-sensing TLRs (TLR7, TLR8, TLR13), suggesting that RAGE is an integral part of the endosomal nucleic acid-sensing system.
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Affiliation(s)
- Damien Bertheloot
- Institute of Innate Immunity, University Hospital, University of Bonn, 53127 Bonn, Germany
| | | | - Pia Langhoff
- Institute of Innate Immunity, University Hospital, University of Bonn, 53127 Bonn, Germany.,German Center for Neurodegenerative Diseases, 53117 Bonn, Germany
| | - Gabor L Horvath
- Institute of Innate Immunity, University Hospital, University of Bonn, 53127 Bonn, Germany
| | - Tengchuan Jin
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Tsan Sam Xiao
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106
| | - Natalio Garbi
- Institute of Molecular Medicine and Experimental Immunology, University of Bonn, 53127 Bonn, Germany
| | | | | | - Eicke Latz
- Institute of Innate Immunity, University Hospital, University of Bonn, 53127 Bonn, Germany; .,German Center for Neurodegenerative Diseases, 53117 Bonn, Germany.,Department of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605
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4
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von Kolontaj K, Horvath GL, Latz E, Büscher M. Automated nanoscale flow cytometry for assessing protein-protein interactions. Cytometry A 2016; 89:835-43. [PMID: 27584593 DOI: 10.1002/cyto.a.22937] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 05/27/2016] [Accepted: 08/14/2016] [Indexed: 11/10/2022]
Abstract
Despite their importance for signalling events, protein-protein interactions cannot easily be analyzed on a single cell level. We developed a robust automated FRET measurement system implemented on a commercial flow cytometer allowing for rapid profiling of molecular associations in living cells. We used this method to measure the most proximal signaling events on human T lymphocyte activation, which preceded calcium influx, and could automatically detect T cell receptor/CD3 complex clustering defects in immunocompromised patients. © 2016 International Society for Advancement of Cytometry.
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Affiliation(s)
- Kerstin von Kolontaj
- Miltenyi Biotec GmbH, Friedrich-Ebert-Straße 68, Bergisch Gladbach, Nordrhein Westfalen, 51429, Germany
| | - Gabor L Horvath
- Institute of Innate Immunity, University Hospitals, University of Bonn, Sigmund-Freud-Str. 25, Bonn, 53127, Germany
| | - Eicke Latz
- Institute of Innate Immunity, University Hospitals, University of Bonn, Sigmund-Freud-Str. 25, Bonn, 53127, Germany. .,Department of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts, 01605. .,German Center for Neurodegenerative Diseases, Bonn, 53175, Germany. .,Centre of Molecular Inflammation Research, Norwegian University of Science and Technology, Trondheim, Norway.
| | - Martin Büscher
- Miltenyi Biotec GmbH, Friedrich-Ebert-Straße 68, Bergisch Gladbach, Nordrhein Westfalen, 51429, Germany.
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5
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Abstract
Protein-protein interactions regulate biological networks. The most proximal events that initiate signal transduction frequently are receptor dimerization or conformational changes in receptor complexes. Toll-like receptors (TLRs) are transmembrane receptors that are activated by a number of exogenous and endogenous ligands. Most TLRs can respond to multiple ligands and the different TLRs recognize structurally diverse molecules ranging from proteins, sugars, lipids, and nucleic acids. TLRs can be expressed on the plasma membrane or in endosomal compartments and ligand recognition thus proceeds in different microenvironments. Not surprisingly, distinctive mechanisms of TLR receptor activation have evolved. A detailed understanding of the mechanisms of TLR activation is important for the development of novel synthetic TLR activators or pharmacological inhibitors of TLRs. Confocal laser scanning microscopy combined with GFP technology allows the direct visualization of TLR expression in living cells. Fluorescence resonance energy transfer (FRET) measurements between two differentially tagged proteins permit the study of TLR interaction, and distances between receptors in the range of molecular interactions can be measured and visualized. Additionally, FRET measurements combined with confocal microscopy provide detailed information about molecular interactions in different subcellular localizations. These techniques permit the dynamic visualization of early signaling events in living cells and can be utilized in pharmacological or genetic screens.
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Affiliation(s)
- Gabor L Horvath
- Institute of Innate Immunity, University Hospitals, University of Bonn, 53127, Bonn, Germany
| | - Pia Langhoff
- Institute of Innate Immunity, University Hospitals, University of Bonn, 53127, Bonn, Germany
| | - Eicke Latz
- Institute of Innate Immunity, University Hospitals, University of Bonn, 53127, Bonn, Germany.
- University of Massachusetts Medical School, Worcester, MA, 01605, USA.
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6
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7
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Sirois CM, Jin T, Miller AL, Bertheloot D, Nakamura H, Horvath GL, Mian A, Jiang J, Schrum J, Bossaller L, Pelka K, Garbi N, Brewah Y, Tian J, Chang CS, Chowdhury P, Sims G, Kolbeck R, Coyle A, Humbles A, Xiao TS, Latz E. RAGE is a nucleic acid receptor that promotes inflammatory responses to DNA. J Biophys Biochem Cytol 2013. [DOI: 10.1083/jcb.2031oia111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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8
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Sirois CM, Jin T, Miller AL, Bertheloot D, Nakamura H, Horvath GL, Mian A, Jiang J, Schrum J, Bossaller L, Pelka K, Garbi N, Brewah Y, Tian J, Chang C, Chowdhury PS, Sims GP, Kolbeck R, Coyle AJ, Humbles AA, Xiao TS, Latz E. RAGE is a nucleic acid receptor that promotes inflammatory responses to DNA. ACTA ACUST UNITED AC 2013; 210:2447-63. [PMID: 24081950 PMCID: PMC3804942 DOI: 10.1084/jem.20120201] [Citation(s) in RCA: 159] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Receptor for advanced glycation end-products (RAGE) detects nucleic acids and promotes DNA uptake into endosomes, which in turn lowers the immune recognition threshold for TLR9 activation. Recognition of DNA and RNA molecules derived from pathogens or self-antigen is one way the mammalian immune system senses infection and tissue damage. Activation of immune signaling receptors by nucleic acids is controlled by limiting the access of DNA and RNA to intracellular receptors, but the mechanisms by which endosome-resident receptors encounter nucleic acids from the extracellular space are largely undefined. In this study, we show that the receptor for advanced glycation end-products (RAGE) promoted DNA uptake into endosomes and lowered the immune recognition threshold for the activation of Toll-like receptor 9, the principal DNA-recognizing transmembrane signaling receptor. Structural analysis of RAGE–DNA complexes indicated that DNA interacted with dimers of the outermost RAGE extracellular domains, and could induce formation of higher-order receptor complexes. Furthermore, mice deficient in RAGE were unable to mount a typical inflammatory response to DNA in the lung, indicating that RAGE is important for the detection of nucleic acids in vivo.
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Affiliation(s)
- Cherilyn M Sirois
- Department of Medicine, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605
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9
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Ablasser A, Schmid-Burgk JL, Hemmerling I, Horvath GL, Schmidt T, Latz E, Hornung V. Cell intrinsic immunity spreads to bystander cells via the intercellular transfer of cGAMP. Nature 2013; 503:530-4. [PMID: 24077100 DOI: 10.1038/nature12640] [Citation(s) in RCA: 438] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 09/10/2013] [Indexed: 12/19/2022]
Abstract
The innate immune defence of multicellular organisms against microbial pathogens requires cellular collaboration. Information exchange allowing immune cells to collaborate is generally attributed to soluble protein factors secreted by pathogen-sensing cells. Cytokines, such as type I interferons (IFNs), serve to alert non-infected cells to the possibility of pathogen challenge. Moreover, in conjunction with chemokines they can instruct specialized immune cells to contain and eradicate microbial infection. Several receptors and signalling pathways exist that couple pathogen sensing to the induction of cytokines, whereas cytosolic recognition of nucleic acids seems to be exquisitely important for the activation of type I IFNs, master regulators of antiviral immunity. Cytosolic DNA is sensed by the receptor cyclic GMP-AMP (cGAMP) synthase (cGAS), which catalyses the synthesis of the second messenger cGAMP(2'-5'). This molecule in turn activates the endoplasmic reticulum (ER)-resident receptor STING, thereby inducing an antiviral state and the secretion of type I IFNs. Here we find in murine and human cells that cGAS-synthesized cGAMP(2'-5') is transferred from producing cells to neighbouring cells through gap junctions, where it promotes STING activation and thus antiviral immunity independently of type I IFN signalling. In line with the limited cargo specificity of connexins, the proteins that assemble gap junction channels, most connexins tested were able to confer this bystander immunity, thus indicating a broad physiological relevance of this local immune collaboration. Collectively, these observations identify cGAS-triggered cGAMP(2'-5') transfer as a novel host strategy that serves to rapidly convey antiviral immunity in a transcription-independent, horizontal manner.
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Affiliation(s)
- Andrea Ablasser
- Institute for Clinical Chemistry and Clinical Pharmacology, University Hospital, University of Bonn, 53127 Bonn, Germany
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10
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Abstract
All inflammasomes require the adapter protein apoptosis associated speck-like protein containing a CARD (ASC) for the activation of caspase-1. After inflammasome activation, ASC assembles into a large protein complex, which is termed "speck". ASC specks can be observed as they reach a size of around 1 μm and in most cells only one speck forms upon inflammasome activation. Hence, ASC speck formation can be used as a simple upstream readout for inflammasome activation. Here, we describe a method for analyzing inflammasome activation by ASC speck visualization. First, we describe the generation of a clonal inflammasome reporter macrophage cell line overexpressing fluorescently tagged ASC. We then discuss stimulation conditions and the microscopic evaluation of ASC speck formation.
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Affiliation(s)
- Andrea Stutz
- Institute of Innate Immunity, University Hospital, University of Bonn, Bonn, Germany
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11
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Abstract
The cells of the innate immune system mobilize a coordinated immune response towards invading microbes and after disturbances in tissue homeostasis. These immune responses typically lead to infection control and tissue repair. Exaggerated or uncontrolled immune responses, however, can also induce acute of chronic inflammatory pathologies that are characteristic for many common diseases such as sepsis, arthritis, atherosclerosis, or Alzheimer's disease. In recent years, the concerted efforts of many scientists have uncovered numerous mechanisms by which immune cells detect foreign or changed self-substances that appear in infections or during tissue damage. These substances stimulate signaling receptors, which leads to cellular activation and the induction of effector mechanisms. Here, we review the role of inflammasomes, a family of signaling molecules that form multi-molecular signaling platforms and activate inflammatory caspases and interleukin-1β cytokines.
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Affiliation(s)
- Gabor L Horvath
- Biomedical Center, Institute of Innate Immunity, University Hospitals, University of Bonn, Bonn, Germany
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