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Jourdi G, Abdoul J, Siguret V, Decleves X, Frezza E, Pailleret C, Gouin-Thibault I, Gandrille S, Neveux N, Samama CM, Pasquali S, Gaussem P. Induced forms of α 2-macroglobulin neutralize heparin and direct oral anticoagulant effects. Int J Biol Macromol 2021; 184:209-217. [PMID: 34126147 DOI: 10.1016/j.ijbiomac.2021.06.058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/07/2021] [Accepted: 06/08/2021] [Indexed: 10/21/2022]
Abstract
Alpha2-macroglobulin (α2M) is a physiological macromolecule that facilitates the clearance of many proteinases, cytokines and growth factors in human. Here, we explored the effect of induced forms of α2M on anticoagulant drugs. Gla-domainless factor Xa (GDFXa) and methylamine (MA)-induced α2M were prepared and characterized by electrophoresis, immunonephelometry, chromogenic, clot waveform and rotational thromboelastometry assays. Samples from healthy volunteers and anticoagulated patients were included. In vivo neutralization of anticoagulants was evaluated in C57Bl/6JRj mouse bleeding-model. Anticoagulant binding sites on induced α2M were depicted by computer-aided energy minimization modeling. GDFXa-induced α2M neutralized dabigatran and heparins in plasma and whole blood. In mice, a single IV dose of GDFXa-induced α2M following anticoagulant administration significantly reduced blood loss and bleeding time. Being far easier to prepare, we investigated the efficacy of MA-induced α2M. It neutralized rivaroxaban, apixaban, dabigatran and heparins in spiked samples in a concentration-dependent manner and in samples from treated patients. Molecular docking analysis evidenced the ability of MA-induced α2M to bind non-covalently these compounds via some deeply buried binding sites. Induced forms of α2M have the potential to neutralize direct oral anticoagulants and heparins, and might be developed as a universal antidote in case of major bleeding or urgent surgery.
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Affiliation(s)
- Georges Jourdi
- Université de Paris, Innovative Therapies in Haemostasis, INSERM UMR_S1140, F-75006, Paris, France; AP-HP. Centre-Université de Paris, Hôpital Cochin, F-75014, Paris, France; Research Centre, Montreal Heart Institute, University of Montreal, Faculty of Pharmacy, Montreal, Canada.
| | - Johan Abdoul
- Université de Paris, Innovative Therapies in Haemostasis, INSERM UMR_S1140, F-75006, Paris, France
| | - Virginie Siguret
- Université de Paris, Innovative Therapies in Haemostasis, INSERM UMR_S1140, F-75006, Paris, France; AP-HP. Nord-Université de Paris, Hôpital Lariboisière, F-75010 Paris, France
| | - Xavier Decleves
- AP-HP. Centre-Université de Paris, Hôpital Cochin, F-75014, Paris, France; Université de Paris, Variabilité de réponse aux psychotropes, INSERM UMR_S1144, F-75006 Paris, France
| | - Elisa Frezza
- Laboratoire CiTCoM, Université de Paris, CNRS, F-75006 Paris, France
| | - Claire Pailleret
- Université de Paris, Innovative Therapies in Haemostasis, INSERM UMR_S1140, F-75006, Paris, France; Clinique du Mont Louis, F-75011 Paris, France
| | - Isabelle Gouin-Thibault
- Laboratoire d'hématologie, CHU Pontchaillou, Université de Rennes 1, CIC-Inserm1414, F-35000 Rennes, France
| | - Sophie Gandrille
- Université de Paris, Innovative Therapies in Haemostasis, INSERM UMR_S1140, F-75006, Paris, France; AP-HP. Centre-Université de Paris, Hôpital Européen Georges Pompidou, F-75015 Paris, France
| | - Nathalie Neveux
- AP-HP. Centre-Université de Paris, Hôpital Cochin, F-75014, Paris, France
| | - Charles Marc Samama
- Université de Paris, Innovative Therapies in Haemostasis, INSERM UMR_S1140, F-75006, Paris, France; AP-HP. Centre-Université de Paris, Hôpital Cochin, F-75014, Paris, France
| | - Samuela Pasquali
- Laboratoire CiTCoM, Université de Paris, CNRS, F-75006 Paris, France
| | - Pascale Gaussem
- Université de Paris, Innovative Therapies in Haemostasis, INSERM UMR_S1140, F-75006, Paris, France; AP-HP. Centre-Université de Paris, Hôpital Européen Georges Pompidou, F-75015 Paris, France.
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Whiten DR, Cox D, Horrocks MH, Taylor CG, De S, Flagmeier P, Tosatto L, Kumita JR, Ecroyd H, Dobson CM, Klenerman D, Wilson MR. Single-Molecule Characterization of the Interactions between Extracellular Chaperones and Toxic α-Synuclein Oligomers. Cell Rep 2019; 23:3492-3500. [PMID: 29924993 PMCID: PMC6024880 DOI: 10.1016/j.celrep.2018.05.074] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 03/26/2018] [Accepted: 05/22/2018] [Indexed: 12/28/2022] Open
Abstract
The aberrant aggregation of α-synuclein is associated with several human diseases, collectively termed the α-synucleinopathies, which includes Parkinson’s disease. The progression of these diseases is, in part, mediated by extracellular α-synuclein oligomers that may exert effects through several mechanisms, including prion-like transfer, direct cytotoxicity, and pro-inflammatory actions. In this study, we show that two abundant extracellular chaperones, clusterin and α2-macroglobulin, directly bind to exposed hydrophobic regions on the surface of α-synuclein oligomers. Using single-molecule fluorescence techniques, we found that clusterin, unlike α2-macroglobulin, exhibits differential binding to α-synuclein oligomers that may be related to structural differences between two previously described forms of αS oligomers. The binding of both chaperones reduces the ability of the oligomers to permeabilize lipid membranes and prevents an oligomer-induced increase in ROS production in cultured neuronal cells. Taken together, these data suggest a neuroprotective role for extracellular chaperones in suppressing the toxicity associated with α-synuclein oligomers. Two extracellular chaperones directly bind to α-synuclein oligomers The binding is mediated by hydrophobicity on the oligomer surface Bound chaperones significantly attenuate the toxicity of α-synuclein oligomers
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Affiliation(s)
- Daniel R Whiten
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK; Illawarra Health and Medical Research Institute, School of Biological Sciences, University of Wollongong, Wollongong 2522, NSW, Australia
| | - Dezerae Cox
- Illawarra Health and Medical Research Institute, School of Biological Sciences, University of Wollongong, Wollongong 2522, NSW, Australia
| | - Mathew H Horrocks
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK; Illawarra Health and Medical Research Institute, School of Biological Sciences, University of Wollongong, Wollongong 2522, NSW, Australia
| | - Christopher G Taylor
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Suman De
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Patrick Flagmeier
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Laura Tosatto
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Janet R Kumita
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Heath Ecroyd
- Illawarra Health and Medical Research Institute, School of Biological Sciences, University of Wollongong, Wollongong 2522, NSW, Australia
| | - Christopher M Dobson
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - David Klenerman
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK; UK Dementia Research Institute, University of Cambridge, Cambridge CB2 0XY, UK.
| | - Mark R Wilson
- Illawarra Health and Medical Research Institute, School of Biological Sciences, University of Wollongong, Wollongong 2522, NSW, Australia.
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Alpha-2-Macroglobulin, a Hypochlorite-Regulated Chaperone and Immune System Modulator. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:5410657. [PMID: 31428227 PMCID: PMC6679887 DOI: 10.1155/2019/5410657] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 06/02/2019] [Indexed: 12/15/2022]
Abstract
Alpha-macroglobulins are ancient proteins that include monomeric, dimeric, and tetrameric family members. In humans, and many other mammals, the predominant alpha-macroglobulin is alpha-2-macroglobulin (α2M), a tetrameric protein that is constitutively abundant in biological fluids (e.g., blood plasma, cerebral spinal fluid, synovial fluid, ocular fluid, and interstitial fluid). α2M is best known for its remarkable ability to inhibit a broad spectrum of proteases, but the full gamut of its activities affects diverse biological processes. For example, α2M can stabilise and facilitate the clearance of the Alzheimer's disease-associated amyloid beta (Aβ) peptide. Additionally, α2M can influence the signalling of cytokines and growth factors including neurotrophins. The results of several studies support the idea that the functions of α2M are uniquely regulated by hypochlorite, an oxidant that is generated during inflammation, which induces the native α2M tetramer to dissociate into dimers. This review will discuss the evidence for hypochlorite-induced regulation of α2M and the possible implications of this in neuroinflammation and neurodegeneration.
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Platón-Corchado M, Barcelona PF, Jmaeff S, Marchena M, Hernández-Pinto AM, Hernández-Sánchez C, Saragovi HU, de la Rosa EJ. p75 NTR antagonists attenuate photoreceptor cell loss in murine models of retinitis pigmentosa. Cell Death Dis 2017; 8:e2922. [PMID: 28703796 PMCID: PMC5550853 DOI: 10.1038/cddis.2017.306] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 04/26/2017] [Accepted: 05/29/2017] [Indexed: 12/23/2022]
Abstract
ProNGF signaling through p75NTR has been associated with neurodegenerative disorders. Retinitis pigmentosa (RP) comprises a group of inherited retinal dystrophies that causes progressive photoreceptor cell degeneration and death, at a rate dependent on the genetic mutation. There are more than 300 mutations causing RP, and this is a challenge to therapy. Our study was designed to explore a common mechanism for p75NTR in the progression of RP, and assess its potential value as a therapeutic target. The proNGF/p75NTR system is present in the dystrophic retina of the rd10 RP mouse model. Compared with wild-type (WT) retina, the levels of unprocessed proNGF were increased in the rd10 retina at early degenerative stages, before the peak of photoreceptor cell death. Conversely, processed NGF levels were similar in rd10 and WT retinas. ProNGF remained elevated throughout the period of photoreceptor cell loss, correlating with increased expression of α2-macroglobulin, an inhibitor of proNGF processing. The neuroprotective effect of blocking p75NTR was assessed in organotypic retinal cultures from rd10 and RhoP mouse models. Retinal explants treated with p75NTR antagonists showed significantly reduced photoreceptor cell death, as determined by the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay and by preservation of the thickness of the outer nuclear layer (ONL), where photoreceptor nuclei are located. This effect was accompanied by decreased retinal-reactive gliosis and reduced TNFα secretion. Use of p75NTR antagonist THX-B (1,3-diisopropyl-1-[2-(1,3-dimethyl-2,6-dioxo-1,2,3,6-tetrahydro-purin-7-yl)-acetyl]-urea) in vivo in the rd10 and RhoP mouse models, by a single intravitreal or subconjunctival injection, afforded neuroprotection to photoreceptor cells, with preservation of the ONL. This study demonstrates a role of the p75NTR/proNGF axis in the progression of RP, and validates these proteins as therapeutic targets in two different RP models, suggesting utility irrespective of etiology.
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Affiliation(s)
| | - Pablo F Barcelona
- Lady Davis Institute-Jewish General Hospital, McGill University, Montreal, QC, Canada
| | - Sean Jmaeff
- Lady Davis Institute-Jewish General Hospital, McGill University, Montreal, QC, Canada
| | | | | | | | - H Uri Saragovi
- Lady Davis Institute-Jewish General Hospital, McGill University, Montreal, QC, Canada
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5
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Zhang C, Huang X, Li J. Light chain amyloidosis: Where are the light chains from and how they play their pathogenic role? Blood Rev 2017; 31:261-270. [PMID: 28336182 DOI: 10.1016/j.blre.2017.03.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Accepted: 03/03/2017] [Indexed: 12/17/2022]
Abstract
Amyloid light-chain (AL) amyloidosis is a plasma-cell dyscrasia, as well as the most common type of systematic amyloidosis. Pathogenic plasma cells that have distinct cytogenetic and molecular properties secrete an excess amount of amyloidogenic light chains. Assisted by post-translational modifications, matrix components, and other environmental factors, these light chains undergo a conformational change that triggers the formation of amyloid fibrils that overrides the extracellular protein quality control system. Moreover, the amyloidogenic light-chain itself is cytotoxic. As a consequence, organ dysfunction is caused by both organ architecture disruption and the direct cytotoxic effect of amyloidogenic light chains. Here, we reviewed the molecular mechanisms underlying this sequence of events that ultimately leads to AL amyloidosis and also discuss current in vitro and in vivo models, as well as relevant novel therapeutic approaches.
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Affiliation(s)
- Chunlan Zhang
- Department of Hematology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Xufei Huang
- Department of Hematology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Jian Li
- Department of Hematology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
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6
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Pate KM, Murphy RM. Cerebrospinal Fluid Proteins as Regulators of Beta-amyloid Aggregation and Toxicity. Isr J Chem 2017; 57:602-612. [PMID: 29129937 DOI: 10.1002/ijch.201600078] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Amyloid disorders, such as Alzheimer's, are almost invariably late-onset diseases. One defining diagnostic feature of Alzheimer's disease is the deposition of beta-amyloid as extracellular plaques, primarily in the hippocampus. This raises the question: are there natural protective agents that prevent beta-amyloid from depositing, and is it loss of this protection that leads to onset of disease? Proteins in cerebrospinal fluid (CSF) have been suggested to act as just such natural protective agents. Here, we describe some of the early evidence that led to this suggestion, and we discuss, in greater detail, two CSF proteins that have garnered the bulk of the attention.
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Affiliation(s)
- Kayla M Pate
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison WI 53706 (USA)
| | - Regina M Murphy
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison WI 53706 (USA)
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7
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A Pro-Nerve Growth Factor (proNGF) and NGF Binding Protein, α2-Macroglobulin, Differentially Regulates p75 and TrkA Receptors and Is Relevant to Neurodegeneration Ex Vivo and In Vivo. Mol Cell Biol 2015. [PMID: 26217017 DOI: 10.1128/mcb.00544-15] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Nerve growth factor (NGF) is generated from a precursor, proNGF, that is proteolytically processed. NGF preferentially binds a trophic tyrosine kinase receptor, TrkA, while proNGF binds a neurotrophin receptor (NTR), p75(NTR), that can have neurotoxic activity. Previously, we along with others showed that the soluble protein α2-macroglobulin (α2M) is neurotoxic. Toxicity is due in part to α2M binding to NGF and inhibiting trophic activity, presumably by preventing NGF binding to TrkA. However, the mechanisms remained unclear. Here, we show ex vivo and in vivo three mechanisms for α2M neurotoxicity. First, unexpectedly the α2M-NGF complexes do bind TrkA receptors but do not induce TrkA dimerization or activation, resulting in deficient trophic support. Second, α2M makes stable complexes with proNGF, conveying resistance to proteolysis that results in more proNGF and less NGF. Third, α2M-proNGF complexes bind p75(NTR) and are more potent agonists than free proNGF, inducing tumor necrosis factor alpha (TNF-α) production. Hence, α2M regulates proNGF/p75(NTR) positively and mature NGF/TrkA negatively, causing neuronal death ex vivo. These three mechanisms are operative in vivo, and α2M causes neurodegeneration in a p75(NTR)- and proNGF-dependent manner. α2M could be exploited as a therapeutic target, or as a modifier of neurotrophin signals.
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8
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Wyatt AR, Kumita JR, Farrawell NE, Dobson CM, Wilson MR. Alpha-2-Macroglobulin Is Acutely Sensitive to Freezing and Lyophilization: Implications for Structural and Functional Studies. PLoS One 2015; 10:e0130036. [PMID: 26103636 PMCID: PMC4477937 DOI: 10.1371/journal.pone.0130036] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 05/15/2015] [Indexed: 12/21/2022] Open
Abstract
Alpha-2-macroglobulin is an abundant secreted protein that is of particular interest because of its diverse ligand binding profile and multifunctional nature, which includes roles as a protease inhibitor and as a molecular chaperone. The activities of alpha-2-macroglobulin are typically dependent on whether its conformation is native or transformed (i.e. adopts a more compact conformation after interactions with proteases or small nucleophiles), and are also influenced by dissociation of the native alpha-2-macroglobulin tetramer into stable dimers. Alpha-2-macroglobulin is predominately present as the native tetramer in vivo; once purified from human blood plasma, however, alpha-2-macroglobulin can undergo a number of conformational changes during storage, including transformation, aggregation or dissociation. We demonstrate that, particularly in the presence of sodium chloride or amine containing compounds, freezing and/or lyophilization of alpha-2-macroglobulin induces conformational changes with functional consequences. These conformational changes in alpha-2-macroglobulin are not always detected by standard native polyacrylamide gel electrophoresis, but can be measured using bisANS fluorescence assays. Increased surface hydrophobicity of alpha-2-macroglobulin, as assessed by bisANS fluorescence measurements, is accompanied by (i) reduced trypsin binding activity, (ii) increased chaperone activity, and (iii) increased binding to the surfaces of SH-SY5Y neurons, in part, via lipoprotein receptors. We show that sucrose (but not glycine) effectively protects native alpha-2-macroglobulin from denaturation during freezing and/or lyophilization, thereby providing a reproducible method for the handling and long-term storage of this protein.
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Affiliation(s)
- Amy R. Wyatt
- Illawarra Health and Medical Research Institute and School of Biological Sciences, University of Wollongong, Wollongong, NSW 2522, Australia
- * E-mail:
| | - Janet R. Kumita
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Natalie E. Farrawell
- Illawarra Health and Medical Research Institute and School of Biological Sciences, University of Wollongong, Wollongong, NSW 2522, Australia
| | | | - Mark R. Wilson
- Illawarra Health and Medical Research Institute and School of Biological Sciences, University of Wollongong, Wollongong, NSW 2522, Australia
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9
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Rehman AA, Ahsan H, Khan FH. α-2-Macroglobulin: a physiological guardian. J Cell Physiol 2013; 228:1665-75. [PMID: 23086799 DOI: 10.1002/jcp.24266] [Citation(s) in RCA: 242] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 10/12/2012] [Indexed: 12/18/2022]
Abstract
Alpha macroglobulins are large glycoproteins which are present in the body fluids of both invertebrates and vertebrates. Alpha-2-macroglobulin (α2 M), a key member of alpha macroglobulin superfamily, is a high-molecular weight homotetrameric glycoprotein. α2 M has many diversified and complex functions, but it is primarily known by its ability to inhibit a broad spectrum of proteases without the direct blockage of the protease active site. α2 M is also known to be involved in the regulation, transport, and a host of other functions. For example, apart from inhibiting proteinases, it regulates binding of transferrin to its surface receptor, binds defensin and myelin basic protein, etc., binds several important cytokines, including basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF), nerve growth factor (NGF), interleukin-1β (IL-1β), and interleukin-6 (IL-6), and modify their biological activity. α2 M also binds a number of hormones and regulates their activity. α2 M is said to protect the body against various infections, and hence, can be used as a biomarker for the diagnosis and prognosis of a number of diseases. However, this multipurpose antiproteinse is not "fail safe" and could be damaged by reactive species generated endogenously or exogenously, leading to various pathophysiological conditions.
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Affiliation(s)
- Ahmed A Rehman
- Faculty of Life Sciences, Department of Biochemistry, Aligarh Muslim University, Aligarh, India
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Affiliation(s)
- Amy R. Wyatt
- School of Biological Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia;
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Justin J. Yerbury
- School of Biological Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia;
| | - Heath Ecroyd
- School of Biological Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia;
| | - Mark R. Wilson
- School of Biological Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia;
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11
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Cascella R, Conti S, Tatini F, Evangelisti E, Scartabelli T, Casamenti F, Wilson MR, Chiti F, Cecchi C. Extracellular chaperones prevent Aβ42-induced toxicity in rat brains. Biochim Biophys Acta Mol Basis Dis 2013; 1832:1217-26. [PMID: 23602994 DOI: 10.1016/j.bbadis.2013.04.012] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 03/12/2013] [Accepted: 04/09/2013] [Indexed: 12/22/2022]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterised by cognitive decline, formation of the extracellular amyloid β (Aβ42) plaques, neuronal and synapse loss, and activated microglia and astrocytes. Extracellular chaperones, which are known to inhibit amyloid fibril formation and promote clearance of misfolded aggregates, have recently been shown to reduce efficiently the toxicity of HypF-N misfolded oligomers to immortalised cell lines, by binding and clustering them into large species. However, the role of extracellular chaperones on Aβ oligomer toxicity remains unclear, with reports often appearing contradictory. In this study we microinjected into the hippocampus of rat brains Aβ42 oligomers pre-incubated for 1h with two extracellular chaperones, namely clusterin and α2-macroglobulin. The chaperones were found to prevent Aβ42-induced learning and memory impairments, as assessed by the Morris Water Maze test, and reduce Aβ42-induced glia inflammation and neuronal degeneration in rat brains, as probed by fluorescent immunohistochemical analyses. Moreover, the chaperones were able to prevent Aβ42 colocalisation with PSD-95 at post-synaptic terminals of rat primary neurons, suppressing oligomer cytotoxicity. All such effects were not effective by adding pre-formed oligomers and chaperones without preincubation. Molecular chaperones have therefore the potential to prevent the early symptoms of AD, not just by inhibiting Aβ42 aggregation, as previously demonstrated, but also by suppressing the toxicity of Aβ42 oligomers after they are formed. These findings elect them as novel neuroprotectors against amyloid-induced injury and excellent candidates for the design of therapeutic strategies against AD.
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Affiliation(s)
- Roberta Cascella
- Department of Biomedical Experimental and Clinical Sciences, University of Florence, V.le GB Morgagni 50, 50134, Italy
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12
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Wyatt AR, Constantinescu P, Ecroyd H, Dobson CM, Wilson MR, Kumita JR, Yerbury JJ. Protease-activated alpha-2-macroglobulin can inhibit amyloid formation via two distinct mechanisms. FEBS Lett 2013; 587:398-403. [PMID: 23353684 PMCID: PMC3581772 DOI: 10.1016/j.febslet.2013.01.020] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 01/04/2013] [Indexed: 11/27/2022]
Abstract
α2-Macroglobulin (α2M) is an extracellular chaperone that inhibits amorphous and fibrillar protein aggregation. The reaction of α2M with proteases results in an ‘activated’ conformation, where the proteases become covalently-linked within the interior of a cage-like structure formed by α2M. This study investigates, the effect of activation on the ability of α2M to inhibit amyloid formation by Aβ1–42 and I59T human lysozyme and shows that protease-activated α2M can act via two distinct mechanisms: (i) by trapping proteases that remain able to degrade polypeptide chains and (ii) by a chaperone action that prevents misfolded clients from continuing along the amyloid forming pathway. Structured summary of protein interactions Aβ1–42 and Aβ1–42 bind by fluorescence technology (View interaction)I59T lysozyme and I59T lysozyme bind by light scattering (View interaction)I59T lysozyme and I59T lysozyme bind by fluorescence technology (View interaction)Alpha-lactalbumin and Alpha-lactalbumin bind by fluorescence technology (View interaction)I59T lysozyme and I59T lysozyme bind by electron microscopy (View interaction)Aβ1–42 and Aβ1–42 bind by electron microscopy (View interaction)
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Affiliation(s)
- Amy R Wyatt
- Illawarra Health & Medical Research Institute, School of Biological Sciences, University of Wollongong, Wollongong, NSW 2522, Australia
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Roles of Extracellular Chaperones in Amyloidosis. J Mol Biol 2012; 421:499-516. [DOI: 10.1016/j.jmb.2012.01.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 01/02/2012] [Accepted: 01/03/2012] [Indexed: 01/24/2023]
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Molecular mechanisms used by chaperones to reduce the toxicity of aberrant protein oligomers. Proc Natl Acad Sci U S A 2012; 109:12479-84. [PMID: 22802614 DOI: 10.1073/pnas.1117799109] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Chaperones are the primary regulators of the proteostasis network and are known to facilitate protein folding, inhibit protein aggregation, and promote disaggregation and clearance of misfolded aggregates inside cells. We have tested the effects of five chaperones on the toxicity of misfolded oligomers preformed from three different proteins added extracellularly to cultured cells. All the chaperones were found to decrease oligomer toxicity significantly, even at very low chaperone/protein molar ratios, provided that they were added extracellularly rather than being overexpressed in the cytosol. Infrared spectroscopy and site-directed labeling experiments using pyrene ruled out structural reorganizations within the discrete oligomers. Rather, confocal microscopy, SDS-PAGE, and intrinsic fluorescence measurements indicated tight binding between oligomers and chaperones. Moreover, atomic force microscopy imaging indicated that larger assemblies of oligomers are formed in the presence of the chaperones. This suggests that the chaperones bind to the oligomers and promote their assembly into larger species, with consequent shielding of the reactive surfaces and a decrease in their diffusional mobility. Overall, the data indicate a generic ability of chaperones to neutralize extracellular misfolded oligomers efficiently and reveal that further assembly of protein oligomers into larger species can be an effective strategy to neutralize such extracellular species.
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Willander H, Presto J, Askarieh G, Biverstål H, Frohm B, Knight SD, Johansson J, Linse S. BRICHOS domains efficiently delay fibrillation of amyloid β-peptide. J Biol Chem 2012; 287:31608-17. [PMID: 22801430 DOI: 10.1074/jbc.m112.393157] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Amyloid diseases such as Alzheimer, Parkinson, and prion diseases are associated with a specific form of protein misfolding and aggregation into oligomers and fibrils rich in β-sheet structure. The BRICHOS domain consisting of ∼100 residues is found in membrane proteins associated with degenerative and proliferative disease, including lung fibrosis (surfactant protein C precursor; pro-SP-C) and familial dementia (Bri2). We find that recombinant BRICHOS domains from Bri2 and pro-SP-C prevent fibril formation of amyloid β-peptides (Aβ(40) and Aβ(42)) far below the stoichiometric ratio. Kinetic experiments show that a main effect of BRICHOS is to prolong the lag time in a concentration-dependent, quantitative, and reproducible manner. An ongoing aggregation process is retarded if BRICHOS is added at any time during the lag phase, but it is too late to interfere at the end of the process. Results from circular dichroism and NMR spectroscopy, as well as analytical size exclusion chromatography, imply that Aβ is maintained as an unstructured monomer during the extended lag phase in the presence of BRICHOS. Electron microscopy shows that although the process is delayed, typical amyloid fibrils are eventually formed also when BRICHOS is present. Structural BRICHOS models display a conserved array of tyrosine rings on a five-stranded β-sheet, with inter-hydroxyl distances suited for hydrogen-bonding peptides in an extended β-conformation. Our data imply that the inhibitory mechanism is reliant on BRICHOS interfering with molecular events during the lag phase.
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Affiliation(s)
- Hanna Willander
- Department of Anatomy, Physiology, and Biochemistry, Swedish University of Agricultural Sciences, The Biomedical Centre, 751 23 Uppsala, Sweden
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Sokolowski JD, Mandell JW. Phagocytic clearance in neurodegeneration. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:1416-28. [PMID: 21435432 DOI: 10.1016/j.ajpath.2010.12.051] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Revised: 12/15/2010] [Accepted: 12/22/2010] [Indexed: 12/14/2022]
Abstract
The cellular and molecular mechanisms of phagocytic clearance of apoptotic cells and debris have been intensely studied in invertebrate model organisms and in the mammalian immune system. This evolutionarily conserved process serves multiple purposes. Uncleared debris from dying cells or aggregated proteins can be toxic and may trigger exaggerated inflammatory responses. Even though apoptotic cell death and debris accumulation are key features of neurodegenerative diseases, relatively little attention has been paid to this important homeostatic function in the central nervous system (CNS). This review attempts to summarize our knowledge of phagocytic clearance in the CNS, with a focus on retinal degeneration, forms of which are caused by mutations in genes within known phagocytic pathways, and on Alzheimer's disease (AD). Interest in phagocytic clearance mechanisms in AD was stimulated by the discovery that immunization could promote phagocytic clearance of amyloid-β; however, much less is known about clearance of neuronal and synaptic corpses in AD and other neurodegenerative diseases. Because the regulation of phagocytic activity is intertwined with cytokine signaling, this review also addresses the relationships among CNS inflammation, glial responses, and phagocytic clearance.
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Affiliation(s)
- Jennifer D Sokolowski
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
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Abstract
The maintenance of the levels and correct folding state of proteins (proteostasis) is a fundamental prerequisite for life. Life has evolved complex mechanisms to maintain proteostasis and many of these that operate inside cells are now well understood. The same cannot yet be said of corresponding processes in extracellular fluids of the human body, where inappropriate protein aggregation is known to underpin many serious diseases such as Alzheimer's disease, type II diabetes and prion diseases. Recent research has uncovered a growing family of abundant extracellular chaperones in body fluids which appear to selectively bind to exposed regions of hydrophobicity on misfolded proteins to inhibit their toxicity and prevent them from aggregating to form insoluble deposits. These extracellular chaperones are also implicated in clearing the soluble, stabilized misfolded proteins from body fluids via receptor-mediated endocytosis for subsequent lysosomal degradation. Recent work also raises the possibility that extracellular chaperones may play roles in modulating the immune response. Future work will better define the in vivo functions of extracellular chaperones in proteostasis and immunology and pave the way for the development of new treatments for serious diseases.
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Dabbs RA, Wyatt AR, Yerbury JJ, Ecroyd H, Wilson MR. Extracellular Chaperones. Top Curr Chem (Cham) 2010. [PMID: 21516385 DOI: 10.1007/128_2010_85] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The maintenance of the levels and correct folding state of proteins (proteostasis) is a fundamental prerequisite for life. Life has evolved complex mechanisms to maintain proteostasis and many of these that operate inside cells are now well understood. The same cannot yet be said of corresponding processes in extracellular fluids of the human body, where inappropriate protein aggregation is known to underpin many serious diseases such as Alzheimer's disease, type II diabetes and prion diseases. Recent research has uncovered a growing family of abundant extracellular chaperones in body fluids which appear to selectively bind to exposed regions of hydrophobicity on misfolded proteins to inhibit their toxicity and prevent them from aggregating to form insoluble deposits. These extracellular chaperones are also implicated in clearing the soluble, stabilized misfolded proteins from body fluids via receptor-mediated endocytosis for subsequent lysosomal degradation. Recent work also raises the possibility that extracellular chaperones may play roles in modulating the immune response. Future work will better define the in vivo functions of extracellular chaperones in proteostasis and immunology and pave the way for the development of new treatments for serious diseases.
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Bjerke M, Portelius E, Minthon L, Wallin A, Anckarsäter H, Anckarsäter R, Andreasen N, Zetterberg H, Andreasson U, Blennow K. Confounding factors influencing amyloid Beta concentration in cerebrospinal fluid. Int J Alzheimers Dis 2010; 2010. [PMID: 20798852 PMCID: PMC2925386 DOI: 10.4061/2010/986310] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Accepted: 06/07/2010] [Indexed: 11/20/2022] Open
Abstract
Background. Patients afflicted with Alzheimer's disease (AD) exhibit a decrease in the cerebrospinal fluid (CSF) concentration of the 42 amino acid form of β-amyloid (Aβ42). However, a high discrepancy between different centers in measured Aβ42 levels reduces the utility of this biomarker as a diagnostic tool and in monitoring the effect of disease modifying drugs. Preanalytical and analytical confounding factors were examined with respect to their effect on the measured Aβ42 level. Methods. Aliquots of CSF samples were either treated differently prior to Aβ42 measurement or analyzed using different commercially available xMAP or ELISA assays.
Results. Confounding factors affecting CSF Aβ42 levels were storage in different types of test tubes, dilution with detergent-containing buffer, plasma contamination, heat treatment, and the origin of the immunoassays used for quantification.
Conclusion. In order to conduct multicenter studies, a standardized protocol to minimize preanalytical and analytical confounding factors is warranted.
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Affiliation(s)
- Maria Bjerke
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at University of Gothenburg, 431 80 Mölndal, Sweden
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An E, Sen S, Park SK, Gordish-Dressman H, Hathout Y. Identification of novel substrates for the serine protease HTRA1 in the human RPE secretome. Invest Ophthalmol Vis Sci 2010; 51:3379-86. [PMID: 20207970 PMCID: PMC2904004 DOI: 10.1167/iovs.09-4853] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Revised: 01/26/2010] [Accepted: 02/18/2010] [Indexed: 01/06/2023] Open
Abstract
PURPOSE. To define the role of the serine protease HTRA1 in age-related macular degeneration (AMD) by examining its expression level and identifying its potential substrates in the context of primary RPE cell extracellular milieu. METHODS. Primary RPE cell cultures were established from human donor eyes and screened for CFH, ARMS2, and HTRA1 risk genotypes by using an allele-discrimination assay. HTRA1 expression in genotyped RPE cells was determined by using real-time PCR and quantitative proteomics. Potential HTRA1 substrates were identified by incubating RPE-conditioned medium with or without human recombinant HTRA1. Selectively cleaved proteins were quantified by using the differential stable isotope labeling by amino acids in cell culture (SILAC) strategy. RESULTS. HTRA1 mRNA levels were threefold higher in primary RPE cells homozygous for the HTRA1 promoter risk allele than in RPE cells with the wild-type allele, which translated into a twofold increase in HTRA1 secretion by RPE cells with the risk genotype. A total of 196 extracellular proteins were identified in the RPE secretome, and only 8 were found to be selectively cleaved by the human recombinant HTRA1. These include fibromodulin with 90% cleavage, clusterin (50%), ADAM9 (54%), vitronectin (54%), and alpha2-macroglobulin (55%), as well as some cell surface proteins including talin-1 (21%), fascin (40%), and chloride intracellular channel protein 1 (51%). CONCLUSIONS. Recombinant HTRA1 cleaves RPE-secreted proteins involved in regulation of the complement pathway (clusterin, vitronectin, and fibromodulin) and of amyloid deposition (clusterin, alpha2-macroglobulin, and ADAM9). These findings suggest a link between HTRA1, complement regulation, and amyloid deposition in AMD pathogenesis.
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Affiliation(s)
- Eunkyung An
- From the Center for Genetic Medicine, Children's National Medical Center, Washington, DC
- the Program in Biochemistry and Molecular Genetics, Institute of Biomedical Science, George Washington University, Washington, DC; and
| | - Supti Sen
- From the Center for Genetic Medicine, Children's National Medical Center, Washington, DC
| | - Sung Kyu Park
- the Department of Cell Biology, The Scripps Research Institute, La Jolla, California
| | | | - Yetrib Hathout
- From the Center for Genetic Medicine, Children's National Medical Center, Washington, DC
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Wyatt A, Yerbury J, Poon S, Dabbs R, Wilson M. Chapter 6: The chaperone action of Clusterin and its putative role in quality control of extracellular protein folding. Adv Cancer Res 2010; 104:89-114. [PMID: 19878774 DOI: 10.1016/s0065-230x(09)04006-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The function(s) of clusterin may depend upon its topological location. A variety of intracellular "isoforms" of clusterin have been reported but further work is required to better define their identity. The secreted form of clusterin has a potent ability to inhibit both amorphous and amyloid protein aggregation. In the case of amorphous protein aggregation, clusterin forms stable, soluble high-molecular-weight complexes with misfolded client proteins. Clusterin expression is increased during many types of physiological and pathological stresses and is thought to function as an extracellular chaperone (EC). The pathology of a variety of serious human diseases is thought to arise as a consequence of the inappropriate aggregation of specific extracellular proteins (e.g., Abeta peptide in Alzheimer's disease and beta(2)-microglobulin in dialysis-related amyloidosis). We have proposed that together with other abundant ECs (e.g., haptoglobin and alpha(2)-macroglobulin), clusterin forms part of a previously unknown quality-control (QC) system for protein folding that mediates the recognition and disposal of extracellular misfolded proteins via receptor-mediated endocytosis and lysosomal degradation. Characterizing the mechanisms of this extracellular QC system will thus have major implications for our understanding of diseases of this type and may eventually lead to the development of new therapies.
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Affiliation(s)
- Amy Wyatt
- School of Biological Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia
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Yerbury JJ, Wilson MR. Extracellular chaperones modulate the effects of Alzheimer's patient cerebrospinal fluid on Abeta(1-42) toxicity and uptake. Cell Stress Chaperones 2010; 15:115-21. [PMID: 19472074 PMCID: PMC2866977 DOI: 10.1007/s12192-009-0122-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2008] [Revised: 04/22/2009] [Accepted: 05/13/2009] [Indexed: 01/03/2023] Open
Abstract
Alzheimer's disease is characterised by the inappropriate death of brain cells and accumulation of the Abeta peptide in the brain. Thus, it is possible that there are fundamental differences between Alzheimer's disease patients and healthy individuals in their abilities to clear Abeta from brain fluid and to protect neurons from Abeta toxicity. In the present study, we examined (1) the cytotoxicity of Alzheimer's disease cerebrospinal fluid (CSF) compared to control CSF, (2) the ability of Alzheimer's disease and control CSF to protect cells from Abeta toxicity and to promote cell-mediated clearance of Abeta and lastly (3) the effects of extracellular chaperones, normally found in CSF, on these processes. We show that the Alzheimer's disease CSF samples tested were more toxic to cultured neuroblastoma cells than normal CSF. In addition, the Alzheimer's disease CSF samples tested were less able to protect cells from Abeta-induced toxicity and less efficient at promoting macrophage-like cell uptake when compared to normal CSF. The addition of physiologically relevant concentrations of the extracellular chaperones, clusterin, haptoglobin and alpha(2)-macroglobulin into CSF protected neuroblastoma cells from Alphabeta(1-42) toxicity and promoted Alphabeta(1-42) uptake in macrophage-like cells. These results suggest that extracellular chaperones are an important element of a system of extracellular protein folding quality control that protects against Abeta toxicity and accumulation.
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Yerbury JJ, Kumita JR, Meehan S, Dobson CM, Wilson MR. alpha2-Macroglobulin and haptoglobin suppress amyloid formation by interacting with prefibrillar protein species. J Biol Chem 2008; 284:4246-54. [PMID: 19074141 DOI: 10.1074/jbc.m807242200] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
alpha(2)-Macroglobulin (alpha(2)M) and haptoglobin (Hp) are both abundant secreted glycoproteins that are best known for their protease trapping and hemoglobin binding activities, respectively. Like the small heat shock proteins, both these glycoproteins have in common the ability to protect a range of proteins from stress-induced amorphous aggregation and have been described as extracellular chaperones. Using an array of biophysical techniques, this study establishes that in vitro at substoichiometric levels and under physiological conditions alpha(2)M and Hp both inhibit the formation of amyloid fibrils from a range of proteins. We also provide evidence that both alpha(2)M and Hp interact with prefibrillar species to maintain the solubility of amyloidogenic proteins. These findings suggest that both alpha(2)M and Hp are likely to play an important role in controlling the inappropriate aggregation of proteins in the extracellular environment.
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Affiliation(s)
- Justin J Yerbury
- School of Biological Sciences, University of Wollongong, Northfields Avenue, Wollongong, New South Wales 2522, Australia
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Shi Z, Rudzinski M, Meerovitch K, Lebrun-Julien F, Birman E, Di Polo A, Saragovi HU. Alpha2-macroglobulin is a mediator of retinal ganglion cell death in glaucoma. J Biol Chem 2008; 283:29156-65. [PMID: 18701465 DOI: 10.1074/jbc.m802365200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Glaucoma is defined as a chronic and progressive optic nerve neuropathy, characterized by apoptosis of retinal ganglion cells (RGC) that leads to irreversible blindness. Ocular hypertension is a major risk factor, but in glaucoma RGC death can persist after ocular hypertension is normalized. To understand the mechanism underlying chronic RGC death we identified and characterized a gene product, alpha2-macroglobulin (alpha2M), whose expression is up-regulated early in ocular hypertension and remains up-regulated long after ocular hypertension is normalized. In ocular hypertension retinal glia up-regulate alpha2M, which binds to low-density lipoprotein receptor-related protein-1 receptors in RGCs, and is neurotoxic in a paracrine fashion. Neutralization of alpha2M delayed RGC loss during ocular hypertension; whereas delivery of alpha2M to normal eyes caused progressive apoptosis of RGC mimicking glaucoma without ocular hypertension. This work adds to our understanding of the pathology and molecular mechanisms of glaucoma, and illustrates emerging paradigms for studying chronic neurodegeneration in glaucoma and perhaps other disorders.
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Affiliation(s)
- ZhiHua Shi
- Lady Davis Institute-Jewish General Hospital, Montreal, Canada
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Trypanosoma cruzi: Alpha-2-macroglobulin regulates host cell apoptosis induced by the parasite infection in vitro. Exp Parasitol 2008; 118:331-7. [DOI: 10.1016/j.exppara.2007.09.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2006] [Revised: 08/10/2007] [Accepted: 09/07/2007] [Indexed: 11/22/2022]
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French K, Yerbury JJ, Wilson MR. Protease activation of alpha2-macroglobulin modulates a chaperone-like action with broad specificity. Biochemistry 2008; 47:1176-85. [PMID: 18171086 DOI: 10.1021/bi701976f] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Alpha2-macroglobulin (alpha2M) is a major human blood glycoprotein best known for its ability to inhibit a broad spectrum of proteases by a unique trapping method. This action induces an "activated" conformation of alpha2M with an exposed binding site for the low-density lipoprotein receptor, facilitating clearance of alpha2M/protease complexes from the body. This report establishes that protease activation also modulates a potent chaperone-like action of alpha2M that has broad specificity for proteins partly unfolded as a result of heat or oxidative stress. Protease-mediated activation of alpha2M abolishes its chaperone-like activity. However, native alpha2M is able to form soluble complexes with stressed proteins and then subsequently become activated by interacting with a protease, providing a potential mechanism for the in vivo clearance of alpha2M/stressed protein/protease complexes. We propose that alpha2M is a newly discovered and unique member of a small group of abundant extracellular proteins with chaperone properties that patrol extracellular spaces for unfolded/misfolded proteins and facilitate their disposal.
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Affiliation(s)
- Katie French
- School of Biological Sciences, University of Wollongong, Northfields Avenue, Wollongong, NSW 2522, Australia
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Wilson MR, Yerbury JJ, Poon S. Potential roles of abundant extracellular chaperones in the control of amyloid formation and toxicity. ACTA ACUST UNITED AC 2008; 4:42-52. [DOI: 10.1039/b712728f] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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28
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Rugsarash W, Tungtrongchitr R, Petmitr S, Phonrat B, Pongpaew P, Harnroongroj T, Tungtrongchitr A. The genetic association between alpha-2-macroglobulin (A2M) gene deletion polymorphism and low serum A2M concentration in overweight/obese Thais. Nutr Neurosci 2006; 9:93-8. [PMID: 16910174 DOI: 10.1080/10284150600771777] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The study subjects were 192 overweight and obese Thais (BMI > 25.00 kg/m2), and 103 Thai controls (BMI = 18.50-24.99 kg/m2), whose ages ranged from 18-60 years. All subjects were evaluated for serum Alpha-2-macroglobulin (A2M), globulin, albumin concentration, and polymorphic variation in the A2M gene. Serum A2M and albumin were significantly lower in the overweight/obese group (P < 0.05). For the overweight/obese and control group, the median ages were 38 and 37 years, serum A2M 200.2; 252.0 (mg/L), albumin 4.4; 4.5 (g/dL), and globulin 3.0; 2.95 (g/dL), respectively. A2M deletion polymorphism genotyping showed no association between A2M deletion polymorphism and the two groupings. At serum A2M concentration < 250 mg/L, there was no relationship between A2M deletion polymorphism and age. Serum A2M had a significant negative correlation with age in all subjects (R = 0.09, P < 0.05). The results did not support the hypothesis that A2M deletion polymorphism is associated with a low A2M concentration in overweight/obese subjects. However, serum A2M had a significant negative correlation with age; serum A2M can possibly be used to indicate the aging of cells in vivo, including the brain. Further studies are needed to investigate other A2M genes located on chromosome 12 to prove A2M gene polymorphism's association with low serum A2M and aging.
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Affiliation(s)
- Wilaiwan Rugsarash
- Department of Tropical Nutrition and Food Science, Faculty of Tropical Medicine, Mahidol University, Ratchathewi, Bangkok, Thailand
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Carter CJ. Convergence of genes implicated in Alzheimer's disease on the cerebral cholesterol shuttle: APP, cholesterol, lipoproteins, and atherosclerosis. Neurochem Int 2006; 50:12-38. [PMID: 16973241 DOI: 10.1016/j.neuint.2006.07.007] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2006] [Revised: 06/30/2006] [Accepted: 07/11/2006] [Indexed: 11/24/2022]
Abstract
Polymorphic genes associated with Alzheimer's disease (see ) delineate a clearly defined pathway related to cerebral and peripheral cholesterol and lipoprotein homoeostasis. They include all of the key components of a glia/neurone cholesterol shuttle including cholesterol binding lipoproteins APOA1, APOA4, APOC1, APOC2, APOC3, APOD, APOE and LPA, cholesterol transporters ABCA1, ABCA2, lipoprotein receptors LDLR, LRP1, LRP8 and VLDLR, and the cholesterol metabolising enzymes CYP46A1 and CH25H, whose oxysterol products activate the liver X receptor NR1H2 and are metabolised to esters by SOAT1. LIPA metabolises cholesterol esters, which are transported by the cholesteryl ester transport protein CETP. The transcription factor SREBF1 controls the expression of most enzymes of cholesterol synthesis. APP is involved in this shuttle as it metabolises cholesterol to 7-betahydroxycholesterol, a substrate of SOAT1 and HSD11B1, binds to APOE and is tethered to LRP1 via APPB1, APBB2 and APBB3 at the cytoplasmic domain and via LRPAP1 at the extracellular domain. APP cleavage products are also able to prevent cholesterol binding to APOE. BACE cleaves both APP and LRP1. Gamma-secretase (PSEN1, PSEN2, NCSTN) cleaves LRP1 and LRP8 as well as APP and their degradation products control transcription factor TFCP2, which regulates thymidylate synthase (TS) and GSK3B expression. GSK3B is known to phosphorylate the microtubule protein tau (MAPT). Dysfunction of this cascade, carved out by genes implicated in Alzheimer's disease, may play a major role in its pathology. Many other genes associated with Alzheimer's disease affect cholesterol or lipoprotein function and/or have also been implicated in atherosclerosis, a feature of Alzheimer's disease, and this duality may well explain the close links between vascular and cerebral pathology in Alzheimer's disease. The definition of many of these genes as risk factors is highly contested. However, when polymorphic susceptibility genes belong to the same signaling pathway, the risk associated with multigenic disease is better related to the integrated effects of multiple polymorphisms of genes within the same pathway than to variants in any single gene [Wu, X., Gu, J., Grossman, H.B., Amos, C.I., Etzel, C., Huang, M., Zhang, Q., Millikan, R.E., Lerner, S., Dinney, C.P., Spitz, M.R., 2006. Bladder cancer predisposition: a multigenic approach to DNA-repair and cell-cycle-control genes. Am. J. Hum. Genet. 78, 464-479.]. Thus, the fact that Alzheimer's disease susceptibility genes converge on a clearly defined signaling network has important implications for genetic association studies.
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Donnelly S, Roake W, Brown S, Young P, Naik H, Wordsworth P, Isenberg DA, Reid KBM, Eggleton P. Impaired recognition of apoptotic neutrophils by the C1q/calreticulin and CD91 pathway in systemic lupus erythematosus. ACTA ACUST UNITED AC 2006; 54:1543-56. [PMID: 16645988 DOI: 10.1002/art.21783] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE A deficiency in a subcomponent of C1q can result in increased susceptibility to autoimmune diseases such as systemic lupus erythematosus (SLE). The monocyte endocytic receptor CD91 is implicated in the endocytosis of apoptotic neutrophils via interactions with C1q and calreticulin. In this clinical study, we studied the binding of C1q to leukocytes and determined whether C1q bound specifically to calreticulin and CD91 on cells undergoing apoptosis in SLE. METHODS Proximal antibody phage display, calreticulin-transfected cells, and immunocytochemical and confocal techniques were used in a comprehensive analysis of direct binding of C1q to apoptotic neutrophils that were obtained from healthy individuals and from patients with SLE. In addition, apoptotic cellular systems were assessed in vitro. RESULTS C1q appeared to colocalize to apoptotic blebs on the surface of leukocytes in association with both calreticulin and CD91, as determined by phage display and transfected cell studies. However, C1q did not bind to apoptotic cells isolated from SLE patients, despite the positivity of the cells for both calreticulin and CD91. Surface expression of calreticulin decreased on neutrophils as they aged, but increased on monocytes. In an apoptotic phagocytic assay, the addition of C1q and calreticulin significantly enhanced the phagocytosis of apoptotic cell debris by monocyte-derived cells. CONCLUSION These observations indicate that neutrophils from SLE patients have a reduced ability to be recognized and removed by the C1q/calreticulin/CD91-mediated apoptotic pathway, despite the presence of main apoptotic recognition partners. This suggests that an additional component, as yet unidentified, acts as a C1q binding partner on apoptotic cells, and this component may be lacking in cells isolated from SLE patients.
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Businaro R, Leone S, Fabrizi C, Sorci G, Donato R, Lauro GM, Fumagalli L. S100B protects LAN-5 neuroblastoma cells against Abeta amyloid-induced neurotoxicity via RAGE engagement at low doses but increases Abeta amyloid neurotoxicity at high doses. J Neurosci Res 2006; 83:897-906. [PMID: 16477616 DOI: 10.1002/jnr.20785] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
At the concentrations normally found in the brain extracellular space the glial-derived protein, S100B, protects neurons against neurotoxic agents by interacting with the receptor for advanced glycation end products (RAGE). It is known that at relatively high concentrations S100B is neurotoxic causing neuronal death via excessive stimulation of RAGE. S100B is detected within senile plaques in Alzheimer's disease, where its role is unknown. The present study was undertaken to evaluate a putative neuroprotective role of S100B against Abeta amyloid-induced neurotoxicity. We treated LAN-5 neuroblastoma cultures with toxic amounts of Abeta25-35 amyloid peptide. Our results show that at nanomolar concentrations S100B protects cells against Abeta-mediated cytotoxicity, as assessed by 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and terminal deoxynucleotidyl transferase-mediated dUTP-fluorescein isothiocyanate nick end-labeling (TUNEL) experiments, by countering the Abeta-mediated decrease in the expression of the anti-apoptotic factor Bcl-2. This effect depends on S100B binding to RAGE because S100B is unable to contrast Abeta-mediated neurotoxicity in neurons overexpressing a signaling-deficient RAGE mutant lacking the cytosolic and transducing domain. Our data suggest that at nanomolar doses S100B counteracts Abeta peptide neurotoxicity in a RAGE-mediated manner. However, at micromolar doses S100B is toxic to LAN-5 cells and its toxicity adds to that of the Abeta peptide, suggesting that additional molecular mechanisms may be involved in the neurotoxic process.
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Affiliation(s)
- R Businaro
- Department of Cardiovascular Sciences, University La Sapienza, Rome, Italy.
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Hauwel M, Furon E, Canova C, Griffiths M, Neal J, Gasque P. Innate (inherent) control of brain infection, brain inflammation and brain repair: the role of microglia, astrocytes, "protective" glial stem cells and stromal ependymal cells. ACTA ACUST UNITED AC 2005; 48:220-33. [PMID: 15850661 DOI: 10.1016/j.brainresrev.2004.12.012] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2004] [Accepted: 12/09/2004] [Indexed: 12/21/2022]
Abstract
In invertebrates and primitive vertebrates, the brain contains large numbers of "professional" macrophages associated with neurones, ependymal tanycytes and radial glia to promote robust regenerative capacity. In higher vertebrates, hematogenous cells are largely excluded from the brain, and innate immune molecules and receptors produced by the resident "amateur" macrophages (microglia, astrocytes and ependymal cells) control pathogen infiltration and clearance of toxic cell debris. However, there is minimal capacity for regeneration. The transfer of function from hematogenous cells to macroglia and microglia is associated with the sophistication of a yet poorly-characterized neurone-glia network. This evolutionary pattern may have been necessary to reduce the risk of autoimmune attack while preserving the neuronal web but the ability to repair central nervous system damage may have been sacrificed in the process. We herein argue that it may be possible to re-educate and stimulate the resident phagocytes to promote clearance of pathogens (e.g., Prion), toxic cell debris (e.g., amyloid fibrils and myelin) and apoptotic cells. Moreover, as part of this greater division of labour between cell types in vertebrate brains, it may be possible to harness the newly described properties of glial stem cells in neuronal protection (revitalization) rather than replacement, and to control brain inflammation. We will also highlight the emerging roles of stromal ependymal cells in controlling stem cell production and migration into areas of brain damage. Understanding the mechanisms involved in the nurturing of damaged neurons by protective glial stem cells with the safe clearance of cell debris could lead to remedial strategies for chronic brain diseases.
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Affiliation(s)
- Mathieu Hauwel
- Department of Medical Biochemistry and Immunology, Brain Inflammation and Immunity Group (BIIG), University of Wales College of Medicine, Tenovus Building, Heath Park, Cardiff, UK
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Mettenburg JM, Arandjelovic S, Gonias SL. A chemically modified preparation of alpha2-macroglobulin binds beta-amyloid peptide with increased affinity and inhibits Abeta cytotoxicity. J Neurochem 2005; 93:53-62. [PMID: 15773905 DOI: 10.1111/j.1471-4159.2004.02995.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Macromolecules that bind beta-amyloid peptide (Abeta) and neutralize Abeta cytotoxicity offer a promising new approach for treating Alzheimer's disease. When the plasma protein, alpha2-macroglobulin (alpha2M), is treated with methylamine (alpha2M-MA), it undergoes conformational change and acquires Abeta-binding activity. In this study, we demonstrate that a chemically stabilized preparation of human alpha2M conformational intermediates (alpha2M-cis-Pt/MA) binds Abeta with greatly increased affinity, compared with alpha2M-MA. alpha2M-cis-Pt/MA was generated by reacting alpha2M with the protein cross-linking reagent, cis-Pt, followed by methylamine. Increased Abeta-binding to alpha2M-cis-Pt/MA was demonstrated by co-migration of radio-iodinated proteins in non-denaturing PAGE, chemical cross-linking, and co-immunoprecipitation. The apparent K(D) for Abeta-binding to alpha2M-cis-Pt/MA was decreased 10-fold, compared with alpha2M-MA, to 29 nm. Native alpha2M demonstrated negligible Abeta-binding, as anticipated. alpha2M-cis-Pt/MA markedly counteracted Abeta-induced C6 cell apoptosis. Essentially complete inhibition of apoptosis was observed even when the Abeta was present at fourfold molar excess to alpha2M-cis-Pt/MA. Under equivalent conditions, alpha2M-MA inhibited apoptosis by 25 +/- 6%. When Abeta and alpha2M-cis-Pt/MA were added to human plasma in vitro, significant binding was detected. No binding was observed when an equivalent concentration of native alpha2M or alpha2M-MA was added to plasma. We propose that alpha2M-cis-Pt/MA is a novel alternative to Abeta-specific antibodies, for studying the efficacy of Abeta-binding agents in vitro and in vivo.
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Affiliation(s)
- Joseph M Mettenburg
- Department of Pathology, University of California, San Diego, La Jolla, California, USA
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Fernández-Madrid F, Tang N, Alansari H, Granda JL, Tait L, Amirikia KC, Moroianu M, Wang X, Karvonen RL. Autoantibodies to Annexin XI-A and Other Autoantigens in the Diagnosis of Breast Cancer. Cancer Res 2004; 64:5089-96. [PMID: 15289310 DOI: 10.1158/0008-5472.can-03-0932] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We report on the identification of autoantigens commonly recognized by sera from patients with breast cancer. We selected ten sera from patients with invasive ductal carcinoma (IDC) of the breast with high titer IgG autoantibodies for biopanning of a T7 phage breast cancer cDNA display library. A high throughput method involved the assembly of 938 T7 phages encoding potential breast cancer autoantigens. Microarrays of positive phages were probed with sera from 90 patients with breast cancer [15 patients with ductal carcinoma in situ (DCIS) and 75 patients with IDC of the breast], with 51 non-cancer control sera and with sera from 21 patients with systemic autoimmune diseases. A 12-phage breast cancer predictor group was constructed with phage inserts recognized by sera from patients with breast cancer and not by non-cancer or autoimmune control sera (P < 0.0001). Several autoantigens including annexin XI-A, the p80 subunit of the Ku antigen, ribosomal protein S6, and other unknown autoantigens could significantly discriminate between breast cancer and non-cancer control sera. Biopanning with three different sera led to the cloning of partial cDNA sequences identical to annexin XI-A. IgG autoantibodies reacting with the amino acid 41-74 sequence of annexin XI-A were found in 19% of all women with breast cancer but in 60% of sera from women with DCIS of the breast. In addition, partial sequences identical to annexin XI-A, nucleolar protein interacting with the forkhead-associated (FHA) domain of pKi-67, the KIAA1671 gene product, ribosomal protein S6, cyclin K, elongation factor-2, Grb2-associated protein 2, and other unknown proteins could distinguish DCIS from IDC of the breast and appear to be potential biomarkers for the diagnosis of breast cancer.
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Affiliation(s)
- Félix Fernández-Madrid
- Department of Internal Medicine, Division of Rheumatology, Wayne Stste University, 4201 St. Antoine Boulevard, Detroit, MI 48201, USA.
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Choi KL, Wang Y, Tse CA, Lam KSL, Cooper GJS, Xu A. Proteomic analysis of adipocyte differentiation: Evidence that α2 macroglobulin is involved in the adipose conversion of 3T3 L1 preadipocytes. Proteomics 2004; 4:1840-8. [PMID: 15174150 DOI: 10.1002/pmic.200300697] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Adipogenesis is an important aspect of energy homeostasis. Here we have used a differential proteome mapping strategy to identify intracellular proteins that are differentially expressed during adipose conversion of 3T3 L1 preadipocytes. Two-dimensional gel electrophoresis analysis identified 8 proteins that are induced following hormone-evoked differentiation. In addition, we found that a alpha2 macroglobulin fragment was abundantly present in 3T3 L1 preadipocytes, but was virtually undetectable in fully differentiated adipocytes. Metabolic radiolabeling with (35S)methionine and Northern blot analysis indicated that the intracellular alpha2 macroglobulin fragment in preadipocytes was derived from the extracellular culture medium, not de novo synthesis. Incubation of preadipocytes with an antialpha2 macroglobulin polyclonal antibody caused depletion of the intracellular alpha2 macroglobulin fragments, and also enhanced spontaneous adipose conversion. These results suggest that intracellular alpha2 macroglobulin fragment inhibits adipocyte differentiation, and that hormone treatment induces differentiation at least in part by suppression of intracellular alpha2 macroglobulin activity in 3T3 L1 preadipocytes.
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Affiliation(s)
- Kai-Luk Choi
- The School of Biological Sciences, University of Auckland, Auckland, New Zealand
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Arandjelovic S, Freed TA, Gonias SL. Growth factor-binding sequence in human alpha2-macroglobulin targets the receptor-binding site in transforming growth factor-beta. Biochemistry 2003; 42:6121-7. [PMID: 12755614 DOI: 10.1021/bi0342158] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
alpha(2)-Macroglobulin (alpha(2)M) binds transforming growth factor-beta1 (TGF-beta1) and TGF-beta2, forcing these growth factors into a state of latency. The mechanism by which this occurs remains unclear. In this paper, we demonstrate that peptides, derived from the structure of human alpha(2)M (amino acids 714-729), bind directly to TGF-beta1 and block the binding of TGF-beta1 to the type I and II TGF-beta receptors. The alpha(2)M-derived peptides are notable for hydrophobic tripeptide sequences (WIW or VVV) and acidic residues (Glu(714) and Asp(719) in the mature alpha(2)M subunit), which may function analogously to the structural elements that mediate TGF-beta-binding in the type II receptor. Mutating Glu(714) and Asp(719) in the alpha(2)M-peptide-GST fusion protein, FP3, which contains the putative growth factor-binding site, significantly decreased the binding affinity of FP3 for TGF-beta1. The alpha(2)M-derived peptides, which bind TGF-beta1, inhibited the interaction of TGF-beta1 with its receptors in fetal bovine heart endothelial cells. The same peptides also inhibited the activity of TGF-beta1 in endothelial cell proliferation assays. These results demonstrate that alpha(2)M-derived peptides target the receptor-binding sequence in TGF-beta.
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Affiliation(s)
- Sanja Arandjelovic
- Department of Biochemistry and Molecular Genetics, Box 800214, Charlottesville, Virginia 22908, USA
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