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Austin M, Burschowsky D, Chan DT, Jenkinson L, Haynes S, Diamandakis A, Seewooruthun C, Addyman A, Fiedler S, Ryman S, Whitehouse J, Slater LH, Hadjinicolaou AV, Gileadi U, Gowans E, Shibata Y, Barnard M, Kaserer T, Sharma P, Luheshi NM, Wilkinson RW, Vaughan TJ, Holt SV, Cerundolo V, Carr MD, Groves MAT. Structural and functional characterization of C0021158, a high-affinity monoclonal antibody that inhibits Arginase 2 function via a novel non-competitive mechanism of action. MAbs 2020; 12:1801230. [PMID: 32880207 PMCID: PMC7531564 DOI: 10.1080/19420862.2020.1801230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 07/06/2020] [Accepted: 07/20/2020] [Indexed: 12/14/2022] Open
Abstract
Arginase 2 (ARG2) is a binuclear manganese metalloenzyme that catalyzes the hydrolysis of L-arginine. The dysregulated expression of ARG2 within specific tumor microenvironments generates an immunosuppressive niche that effectively renders the tumor 'invisible' to the host's immune system. Increased ARG2 expression leads to a concomitant depletion of local L-arginine levels, which in turn leads to suppression of anti-tumor T-cell-mediated immune responses. Here we describe the isolation and characterization of a high affinity antibody (C0021158) that inhibits ARG2 enzymatic function completely, effectively restoring T-cell proliferation in vitro. Enzyme kinetic studies confirmed that C0021158 exhibits a noncompetitive mechanism of action, inhibiting ARG2 independently of L-arginine concentrations. To elucidate C0021158's inhibitory mechanism at a structural level, the co-crystal structure of the Fab in complex with trimeric ARG2 was solved. C0021158's epitope was consequently mapped to an area some distance from the enzyme's substrate binding cleft, indicating an allosteric mechanism was being employed. Following C0021158 binding, distinct regions of ARG2 undergo major conformational changes. Notably, the backbone structure of a surface-exposed loop is completely rearranged, leading to the formation of a new short helix structure at the Fab-ARG2 interface. Moreover, this large-scale structural remodeling at ARG2's epitope translates into more subtle changes within the enzyme's active site. An arginine residue at position 39 is reoriented inwards, sterically impeding the binding of L-arginine. Arg39 is also predicted to alter the pKA of a key catalytic histidine residue at position 160, further attenuating ARG2's enzymatic function. In silico molecular docking simulations predict that L-arginine is unable to bind effectively when antibody is bound, a prediction supported by isothermal calorimetry experiments using an L-arginine mimetic. Specifically, targeting ARG2 in the tumor microenvironment through the application of C0021158, potentially in combination with standard chemotherapy regimens or alternate immunotherapies, represents a potential new strategy to target immune cold tumors.
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Affiliation(s)
- Mark Austin
- Cancer Research UK AstraZeneca Antibody Alliance Laboratory, Cambridge, UK
- Antibody Discovery & Protein Engineering, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Daniel Burschowsky
- Leicester Institute of Structural and Chemical Biology and the Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - Denice T.Y. Chan
- Cancer Research UK AstraZeneca Antibody Alliance Laboratory, Cambridge, UK
| | - Lesley Jenkinson
- Cancer Research UK AstraZeneca Antibody Alliance Laboratory, Cambridge, UK
| | - Stuart Haynes
- Cancer Research UK AstraZeneca Antibody Alliance Laboratory, Cambridge, UK
| | - Agata Diamandakis
- Cancer Research UK AstraZeneca Antibody Alliance Laboratory, Cambridge, UK
| | - Chitra Seewooruthun
- Leicester Institute of Structural and Chemical Biology and the Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - Alexandra Addyman
- Cancer Research UK AstraZeneca Antibody Alliance Laboratory, Cambridge, UK
| | - Sebastian Fiedler
- Cancer Research UK AstraZeneca Antibody Alliance Laboratory, Cambridge, UK
| | - Stephanie Ryman
- Cancer Research UK AstraZeneca Antibody Alliance Laboratory, Cambridge, UK
| | - Jessica Whitehouse
- Cancer Research UK AstraZeneca Antibody Alliance Laboratory, Cambridge, UK
| | - Louise H. Slater
- Cancer Research UK AstraZeneca Antibody Alliance Laboratory, Cambridge, UK
| | - Andreas V. Hadjinicolaou
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Uzi Gileadi
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Ellen Gowans
- Cancer Research UK AstraZeneca Antibody Alliance Laboratory, Cambridge, UK
| | - Yoko Shibata
- Cancer Research UK AstraZeneca Antibody Alliance Laboratory, Cambridge, UK
| | - Michelle Barnard
- Cancer Research UK AstraZeneca Antibody Alliance Laboratory, Cambridge, UK
| | - Teresa Kaserer
- Cancer Research UK, Cancer Therapeutics Unit, The Institute of Cancer Research, London, UK
| | - Pooja Sharma
- Cancer Research UK AstraZeneca Antibody Alliance Laboratory, Cambridge, UK
| | - Nadia M. Luheshi
- Early Oncology Discovery, Oncology R&D, AstraZeneca, Cambridge, UK
| | | | - Tristan J. Vaughan
- Antibody Discovery & Protein Engineering, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Sarah V. Holt
- Cancer Research UK AstraZeneca Antibody Alliance Laboratory, Cambridge, UK
| | - Vincenzo Cerundolo
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Mark D. Carr
- Leicester Institute of Structural and Chemical Biology and the Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - Maria A. T. Groves
- Cancer Research UK AstraZeneca Antibody Alliance Laboratory, Cambridge, UK
- Antibody Discovery & Protein Engineering, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
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2
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Tapia VS, Daniels MJD, Palazón-Riquelme P, Dewhurst M, Luheshi NM, Rivers-Auty J, Green J, Redondo-Castro E, Kaldis P, Lopez-Castejon G, Brough D. The three cytokines IL-1β, IL-18, and IL-1α share related but distinct secretory routes. J Biol Chem 2019; 294:8325-8335. [PMID: 30940725 PMCID: PMC6544845 DOI: 10.1074/jbc.ra119.008009] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [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: 02/13/2019] [Revised: 03/20/2019] [Indexed: 12/14/2022] Open
Abstract
Interleukin (IL)-1 family cytokines potently regulate inflammation, with the majority of the IL-1 family proteins being secreted from immune cells via unconventional pathways. In many cases, secretion of IL-1 cytokines appears to be closely coupled to cell death, yet the secretory mechanisms involved remain poorly understood. Here, we studied the secretion of the three best-characterized members of the IL-1 superfamily, IL-1α, IL-1β, and IL-18, in a range of conditions and cell types, including murine bone marrow–derived and peritoneal macrophages, human monocyte–derived macrophages, HeLa cells, and mouse embryonic fibroblasts. We discovered that IL-1β and IL-18 share a common secretory pathway that depends upon membrane permeability and can operate in the absence of complete cell lysis and cell death. We also found that the pathway regulating the trafficking of IL-1α is distinct from the pathway regulating IL-1β and IL-18. Although the release of IL-1α could also be dissociated from cell death, it was independent of the effects of the membrane-stabilizing agent punicalagin, which inhibited both IL-1β and IL-18 release. These results reveal that in addition to their role as danger signals released from dead cells, IL-1 family cytokines can be secreted in the absence of cell death. We propose that models used in the study of IL-1 release should be considered context-dependently.
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Affiliation(s)
- Victor S Tapia
- Lydia Becker Institute of Immunology and Inflammation, University of Manchester, Manchester M13 9PT, United Kingdom; Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, AV Hill Building, Oxford Road, Manchester M13 9PT, United Kingdom
| | - Michael J D Daniels
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, AV Hill Building, Oxford Road, Manchester M13 9PT, United Kingdom; UK Dementia Research Institute, University of Edinburgh, College of Medicine and Veterinary Medicine, 49 Little France Crescent, Edinburgh EH16 4SB, Scotland, United Kingdom
| | - Pablo Palazón-Riquelme
- Division of Infection, Immunity, and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Collaborative Centre of Inflammation Research, Manchester Academic Health Science Centre, Core Technology Facility, University of Manchester, Manchester M13 9PT, United Kingdom; International Centre for Infectiology Research, INSERM U1111, CNRS UMR5308, École Normale Supérieure de Lyon, Claude Bernard Lyon 1 University, 69100 Lyon, France
| | - Matthew Dewhurst
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, AV Hill Building, Oxford Road, Manchester M13 9PT, United Kingdom; Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Department of Biochemistry, National University of Singapore (NUS), Singapore 119007, Singapore
| | - Nadia M Luheshi
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, AV Hill Building, Oxford Road, Manchester M13 9PT, United Kingdom; MedImmune Ltd., Aaron Klug Building, Granta Park, Cambridge CB21 6GH, United Kingdom
| | - Jack Rivers-Auty
- Lydia Becker Institute of Immunology and Inflammation, University of Manchester, Manchester M13 9PT, United Kingdom; Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, AV Hill Building, Oxford Road, Manchester M13 9PT, United Kingdom
| | - Jack Green
- Lydia Becker Institute of Immunology and Inflammation, University of Manchester, Manchester M13 9PT, United Kingdom; Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, AV Hill Building, Oxford Road, Manchester M13 9PT, United Kingdom
| | - Elena Redondo-Castro
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, AV Hill Building, Oxford Road, Manchester M13 9PT, United Kingdom
| | - Philipp Kaldis
- Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Department of Biochemistry, National University of Singapore (NUS), Singapore 119007, Singapore
| | - Gloria Lopez-Castejon
- Lydia Becker Institute of Immunology and Inflammation, University of Manchester, Manchester M13 9PT, United Kingdom; Division of Infection, Immunity, and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Collaborative Centre of Inflammation Research, Manchester Academic Health Science Centre, Core Technology Facility, University of Manchester, Manchester M13 9PT, United Kingdom.
| | - David Brough
- Lydia Becker Institute of Immunology and Inflammation, University of Manchester, Manchester M13 9PT, United Kingdom; Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, AV Hill Building, Oxford Road, Manchester M13 9PT, United Kingdom.
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Luheshi NM, Coates-Ulrichsen J, Harper J, Mullins S, Sulikowski MG, Martin P, Brown L, Lewis A, Davies G, Morrow M, Wilkinson RW. Transformation of the tumour microenvironment by a CD40 agonist antibody correlates with improved responses to PD-L1 blockade in a mouse orthotopic pancreatic tumour model. Oncotarget 2017; 7:18508-20. [PMID: 26918344 PMCID: PMC4951305 DOI: 10.18632/oncotarget.7610] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [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: 12/18/2015] [Accepted: 02/14/2016] [Indexed: 01/05/2023] Open
Abstract
Despite the availability of recently developed chemotherapy regimens, survival times for pancreatic cancer patients remain poor. These patients also respond poorly to immune checkpoint blockade therapies (anti-CTLA-4, anti-PD-L1, anti-PD-1), which suggests the presence of additional immunosuppressive mechanisms in the pancreatic tumour microenvironment (TME). CD40 agonist antibodies (αCD40) promote antigen presenting cell (APC) maturation and enhance macrophage tumouricidal activity, and may therefore alter the pancreatic TME to increase sensitivity to immune checkpoint blockade. Here, we test whether αCD40 transforms the TME in a mouse syngeneic orthotopic model of pancreatic cancer, to increase sensitivity to PD-L1 blockade. We found that whilst mice bearing orthotopic Pan02 tumours responded poorly to PD-L1 blockade, αCD40 improved overall survival. αCD40 transformed the TME, upregulating Th1 chemokines, increasing cytotoxic T cell infiltration and promoting formation of an immune cell-rich capsule separating the tumour from the normal pancreas. Furthermore, αCD40 drove systemic APC maturation, memory T cell expansion, and upregulated tumour and systemic PD-L1 expression. Combining αCD40 with PD-L1 blockade enhanced anti-tumour immunity and improved overall survival versus either monotherapy. These data provide further support for the potential of combining αCD40 with immune checkpoint blockade to promote anti-tumour immunity in pancreatic cancer.
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Affiliation(s)
| | | | | | | | | | | | - Lee Brown
- MedImmune Ltd., Cambridge CB21 6GH, UK
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4
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Borrok MJ, Luheshi NM, Beyaz N, Davies GC, Legg JW, Wu H, Dall'Acqua WF, Tsui P. Enhancement of antibody-dependent cell-mediated cytotoxicity by endowing IgG with FcαRI (CD89) binding. MAbs 2016; 7:743-51. [PMID: 25970007 DOI: 10.1080/19420862.2015.1047570] [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] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Fc effector functions such as antibody-dependent cell-mediated cytotoxicity (ADCC) and antibody-dependent cell-mediated phagocytosis (ADCP) are crucial to the efficacy of many antibody therapeutics. In addition to IgG, antibodies of the IgA isotype can also promote cell killing through engagement of myeloid lineage cells via interactions between the IgA-Fc and FcαRI (CD89). Herein, we describe a unique, tandem IgG1/IgA2 antibody format in the context of a trastuzumab variable domain that exhibits enhanced ADCC and ADCP capabilities. The IgG1/IgA2 tandem Fc format retains IgG1 FcγR binding as well as FcRn-mediated serum persistence, yet is augmented with myeloid cell-mediated effector functions via FcαRI/IgA Fc interactions. In this work, we demonstrate anti-human epidermal growth factor receptor-2 antibodies with the unique tandem IgG1/IgA2 Fc can better recruit and engage cytotoxic polymorphonuclear (PMN) cells than either the parental IgG1 or IgA2. Pharmacokinetics of IgG1/IgA2 in BALB/c mice are similar to the parental IgG, and far surpass the poor serum persistence of IgA2. The IgG1/IgA2 format is expressed at similar levels and with similar thermal stability to IgG1, and can be purified via standard protein A chromatography. The tandem IgG1/IgA2 format could potentially augment IgG-based immunotherapeutics with enhanced PMN-mediated cytotoxicity while avoiding many of the problems associated with developing IgAs.
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Key Words
- ADCC
- ADCC, antibody-dependent cell-mediated cytotoxicity
- ADCP, antibody-dependent cell-mediated phagocytosis
- AUC, area under the curve; CL, clearance rate
- CD89
- CDC, complement dependent cytotoxicity
- Cmax, maximum serum concentration
- DSC, differential scanning calorimetry
- E:T ratio, effector to target ratio
- FCM, flow cytometry
- FcRn, neonatal Fc receptor
- FcαRI
- FcγR, Fc gamma receptor
- HER2, human epithelial receptor two
- IgA
- IgA, immunoglobulin A
- IgG, immunoglobulin G
- LDH, lactate dehydrogenase
- MΦ, macrophage
- NK, natural killer
- PBMC, peripheral blood mononuclear cell
- PK, pharmacokinetics
- PMN, polymorphonuclear
- SPR, surface plasmon resonance
- TAA, tumor associated antigens
- T½, half-life
- Vss, central compartment volume of distribution
- macrophage
- monoclonal antibody
- neutrophil
- tandem
- trastuzumab
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Affiliation(s)
- M Jack Borrok
- a Antibody Discovery and Protein Engineering; Medimmune Ltd. ; Gaithersburg , MD , USA
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5
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Summersgill H, England H, Lopez-Castejon G, Lawrence CB, Luheshi NM, Pahle J, Mendes P, Brough D. Zinc depletion regulates the processing and secretion of IL-1β. Cell Death Dis 2014; 5:e1040. [PMID: 24481454 PMCID: PMC4040701 DOI: 10.1038/cddis.2013.547] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [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: 08/29/2013] [Revised: 12/09/2013] [Accepted: 12/09/2013] [Indexed: 01/06/2023]
Abstract
Sterile inflammation contributes to many common and serious human diseases. The pro-inflammatory cytokine interleukin-1β (IL-1β) drives sterile inflammatory responses and is thus a very attractive therapeutic target. Activation of IL-1β in sterile diseases commonly requires an intracellular multi-protein complex called the NLRP3 (NACHT, LRR, and PYD domains-containing protein 3) inflammasome. A number of disease-associated danger molecules are known to activate the NLRP3 inflammasome. We show here that depletion of zinc from macrophages, a paradigm for zinc deficiency, also activates the NLRP3 inflammasome and induces IL-1β secretion. Our data suggest that zinc depletion damages the integrity of lysosomes and that this event is important for NLRP3 activation. These data provide new mechanistic insight to how zinc deficiency contributes to inflammation and further unravel the mechanisms of NLRP3 inflammasome activation.
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Affiliation(s)
- H Summersgill
- Faculty of Life Sciences, University of Manchester, AV Hill Building, Oxford Road, Manchester, UK
| | - H England
- Faculty of Life Sciences, University of Manchester, AV Hill Building, Oxford Road, Manchester, UK
| | - G Lopez-Castejon
- Faculty of Life Sciences, University of Manchester, AV Hill Building, Oxford Road, Manchester, UK
| | - C B Lawrence
- Faculty of Life Sciences, University of Manchester, AV Hill Building, Oxford Road, Manchester, UK
| | - N M Luheshi
- 1] Faculty of Life Sciences, University of Manchester, AV Hill Building, Oxford Road, Manchester, UK [2] MedImmune Ltd, Aaron Klug Building, Granta Park, Cambridge, UK
| | - J Pahle
- School of Computer Science, University of Manchester, Manchester, UK
| | - P Mendes
- School of Computer Science, University of Manchester, Manchester, UK
| | - D Brough
- Faculty of Life Sciences, University of Manchester, AV Hill Building, Oxford Road, Manchester, UK
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Lopez-Castejon G, Luheshi NM, Compan V, High S, Whitehead RC, Flitsch S, Kirov A, Prudovsky I, Swanton E, Brough D. Deubiquitinases regulate the activity of caspase-1 and interleukin-1β secretion via assembly of the inflammasome. J Biol Chem 2012; 288:2721-33. [PMID: 23209292 PMCID: PMC3554938 DOI: 10.1074/jbc.m112.422238] [Citation(s) in RCA: 139] [Impact Index Per Article: 11.6] [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] [Indexed: 01/01/2023] Open
Abstract
IL-1β is a potent pro-inflammatory cytokine produced in response to infection or injury. It is synthesized as an inactive precursor that is activated by the protease caspase-1 within a cytosolic molecular complex called the inflammasome. Assembly of this complex is triggered by a range of structurally diverse damage or pathogen associated stimuli, and the signaling pathways through which these act are poorly understood. Ubiquitination is a post-translational modification essential for maintaining cellular homeostasis. It can be reversed by deubiquitinase enzymes (DUBs) that remove ubiquitin moieties from the protein thus modifying its fate. DUBs present specificity toward different ubiquitin chain topologies and are crucial for recycling ubiquitin molecules before protein degradation as well as regulating key cellular processes such as protein trafficking, gene transcription, and signaling. We report here that small molecule inhibitors of DUB activity inhibit inflammasome activation. Inhibition of DUBs blocked the processing and release of IL-1β in both mouse and human macrophages. DUB activity was necessary for inflammasome association as DUB inhibition also impaired ASC oligomerization and caspase-1 activation without directly blocking caspase-1 activity. These data reveal the requirement for DUB activity in a key reaction of the innate immune response and highlight the therapeutic potential of DUB inhibitors for chronic auto-inflammatory diseases.
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Affiliation(s)
- Gloria Lopez-Castejon
- AV Hill Building, Faculty of Life Sciences, University of Manchester Manchester, M13 9PT, United Kingdom
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7
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Luheshi NM, Kovács KJ, Lopez-Castejon G, Brough D, Denes A. Interleukin-1α expression precedes IL-1β after ischemic brain injury and is localised to areas of focal neuronal loss and penumbral tissues. J Neuroinflammation 2011; 8:186. [PMID: 22206506 PMCID: PMC3259068 DOI: 10.1186/1742-2094-8-186] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [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: 09/02/2011] [Accepted: 12/29/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cerebral ischemia is a devastating condition in which the outcome is heavily influenced by inflammatory processes, which can augment primary injury caused by reduced blood supply. The cytokines interleukin-1α (IL-1α) and IL-1β are key contributors to ischemic brain injury. However, there is very little evidence that IL-1 expression occurs at the protein level early enough (within hours) to influence brain damage after stroke. In order to determine this we investigated the temporal and spatial profiles of IL-1α and IL-1β expression after cerebral ischemia. FINDINGS We report here that in mice, as early as 4 h after reperfusion following ischemia induced by occlusion of the middle cerebral artery, IL-1α, but not IL-1β, is expressed by microglia-like cells in the ischemic hemisphere, which parallels an upregulation of IL-1α mRNA. 24 h after ischemia IL-1α expression is closely associated with areas of focal blood brain barrier breakdown and neuronal death, mostly near the penumbra surrounding the infarct. The sub-cellular distribution of IL-1α in injured areas is not uniform suggesting that it is regulated. CONCLUSIONS The early expression of IL-1α in areas of focal neuronal injury suggests that it is the major form of IL-1 contributing to inflammation early after cerebral ischemia. This adds to the growing body of evidence that IL-1α is a key mediator of the sterile inflammatory response.
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Luheshi NM, Giles JA, Lopez-Castejon G, Brough D. Sphingosine regulates the NLRP3-inflammasome and IL-1β release from macrophages. Eur J Immunol 2011; 42:716-25. [PMID: 22105559 PMCID: PMC3491674 DOI: 10.1002/eji.201142079] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [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: 09/02/2011] [Accepted: 11/14/2011] [Indexed: 12/20/2022]
Abstract
Interleukin-1β (IL-1β) is a pro-inflammatory cytokine that regulates inflammatory responses to injury and infection. IL-1β secretion requires the protease caspase-1, which is activated following recruitment to inflammasomes. Endogenous danger-associated molecular patterns (DAMPs) released from necrotic cells activate caspase-1 through an NLRP3-inflammasome. Here, we show that the endogenous lipid metabolite sphingosine (Sph) acts as a DAMP by inducing the NLRP3-inflammasome-dependent secretion of IL-1β from macrophages. This process was dependent upon serine/threonine protein phosphatases since the PP1/PP2A inhibitors okadaic acid and calyculin A inhibited Sph-induced IL-1β release. IL-1β release induced by other well-characterized NLRP3-inflammasome activators, such as ATP and uric acid crystals, in addition to NLRC4 and AIM2 inflammasome activators was also blocked by these inhibitors. Thus, we propose Sph as a new DAMP, and that a serine/threonine phosphatase (PP1/PP2A)-dependent signal is central to the endogenous host mechanism through which diverse stimuli regulate inflammasome activation.
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Affiliation(s)
- Nadia M Luheshi
- Faculty of Life Sciences, University of Manchester, Manchester, UK
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Abstract
Sterile inflammation is a host response to tissue injury that is mediated by damage-associated molecular patterns released from dead cells. Sterile inflammation worsens damage in a number of injury paradigms. The pro-inflammatory cytokine IL-1 alpha is reported to be a damage-associated molecular pattern released from dead cells, and it is known to exacerbate brain injury caused by stroke. In the brain, IL-1 alpha is produced by microglia, the resident brain macrophages. We found that IL-1 alpha is actively trafficked to the nuclei of microglia, and hence tested the hypothesis that trafficking of IL-1 alpha to the nucleus would inhibit its release following necrotic cell death, limiting sterile inflammation. Microglia subjected to oxygen-glucose deprivation died via necrosis. Under these conditions, microglia expressing nuclear IL-1 alpha released significantly less IL-1 alpha than microglia with predominantly cytosolic IL-1 alpha. The remaining IL-1 alpha was immobilized in the nuclei of the dead cells. Thus, nuclear retention of IL-1 alpha may serve to limit inflammation following cell death.
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Affiliation(s)
- Nadia M Luheshi
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, UK
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10
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Abstract
Dysregulated inflammation contributes to disease pathogenesis in both the periphery and the brain. Cytokines are coordinators of inflammation and were originally defined as secreted mediators, released from expressing cells to activate plasma membrane receptors on responsive cells. However, a group of cytokines is now recognized as having dual functionality. In addition to their extracellular effects, these cytokines act inside the nuclei of cytokine-expressing or cytokine-responsive cells. Interleukin-1 (IL-1) family cytokines are key pro-inflammatory mediators, and blockade of the IL-1 system in inflammatory diseases is an attractive therapeutic goal. All current therapies target IL-1 extracellular actions. Here we review evidence that suggests IL-1 family members have dual functionality. Several IL-1 family members have been detected inside the nuclei of IL-1-expressing or IL-1-responsive cells, and intranuclear IL-1 is reported to regulate gene transcription and mRNA splicing. However, further work is required to determine the impact of IL-1 intranuclear actions on disease pathogenesis. The intranuclear actions of IL-1 family members represent a new and potentially important area of IL-1 biology and may have implications for the future development of anti-IL-1 therapies.
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Affiliation(s)
- N M Luheshi
- Faculty of Life Sciences, University of Manchester, Manchester, UK.
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11
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Abstract
Pro-inflammatory members of the interleukin-1 (IL-1) family of cytokines (IL-1α and β) are important mediators of host defense responses to infection but can also exacerbate the damaging inflammation that contributes to major human diseases. IL-1α and β are produced by cells of the innate immune system, such as macrophages, and act largely after their secretion by binding to the type I IL-1 receptor on responsive cells. There is evidence that IL-1α is also a nuclear protein that can act intracellularly. In this study, we report that both IL-1α and IL-1β produced by microglia (central nervous system macrophages) in response to an inflammatory challenge are distributed between the cytosol and the nucleus. Using IL-1-β-galactosidase and IL-1-green fluorescent protein chimeras (analyzed by fluorescence recovery after photobleaching), we demonstrate that nuclear import of IL-1α is exclusively active, requiring a nuclear localization sequence and Ran, while IL-1β nuclear import is entirely passive. These data provide valuable insights into the dynamic regulation of intracellular cytokine trafficking.
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Affiliation(s)
- Nadia M Luheshi
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, UK
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