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Wilson MR, Satapathy S, Vendruscolo M. Extracellular protein homeostasis in neurodegenerative diseases. Nat Rev Neurol 2023; 19:235-245. [PMID: 36828943 DOI: 10.1038/s41582-023-00786-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/02/2023] [Indexed: 02/26/2023]
Abstract
The protein homeostasis (proteostasis) system encompasses the cellular processes that regulate protein synthesis, folding, concentration, trafficking and degradation. In the case of intracellular proteostasis, the identity and nature of these processes have been extensively studied and are relatively well known. By contrast, the mechanisms of extracellular proteostasis are yet to be fully elucidated, although evidence is accumulating that their age-related progressive impairment might contribute to neuronal death in neurodegenerative diseases. Constitutively secreted extracellular chaperones are emerging as key players in processes that operate to protect neurons and other brain cells by neutralizing the toxicity of extracellular protein aggregates and promoting their safe clearance and disposal. Growing evidence indicates that these extracellular chaperones exert multiple effects to promote cell viability and protect neurons against pathologies arising from the misfolding and aggregation of proteins in the synaptic space and interstitial fluid. In this Review, we outline the current knowledge of the mechanisms of extracellular proteostasis linked to neurodegenerative diseases, and we examine the latest understanding of key molecules and processes that protect the brain from the pathological consequences of extracellular protein aggregation and proteotoxicity. Finally, we contemplate possible therapeutic opportunities for neurodegenerative diseases on the basis of this emerging knowledge.
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Affiliation(s)
- Mark R Wilson
- School of Chemistry and Molecular Bioscience, Molecular Horizons Research Institute, University of Wollongong, Wollongong, New South Wales, Australia.
| | - Sandeep Satapathy
- Blavatnik Institute of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Michele Vendruscolo
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
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2
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The Extracellular Molecular Chaperone Clusterin Inhibits Amyloid Fibril Formation and Suppresses Cytotoxicity Associated with Semen-Derived Enhancer of Virus Infection (SEVI). Cells 2022; 11:cells11203259. [PMID: 36291126 PMCID: PMC9600718 DOI: 10.3390/cells11203259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 10/07/2022] [Accepted: 10/13/2022] [Indexed: 11/17/2022] Open
Abstract
Clusterin is a glycoprotein present at high concentrations in many extracellular fluids, including semen. Its increased expression accompanies disorders associated with extracellular amyloid fibril accumulation such as Alzheimer’s disease. Clusterin is an extracellular molecular chaperone which prevents the misfolding and amorphous and amyloid fibrillar aggregation of a wide variety of unfolding proteins. In semen, amyloid fibrils formed from a 39-amino acid fragment of prostatic acid phosphatase, termed Semen-derived Enhancer of Virus Infection (SEVI), potentiate HIV infectivity. In this study, clusterin potently inhibited the in vitro formation of SEVI fibrils, along with dissociating them. Furthermore, clusterin reduced the toxicity of SEVI to pheochromocytoma-12 cells. In semen, clusterin may play an important role in preventing SEVI amyloid fibril formation, in dissociating SEVI fibrils and in mitigating their enhancement of HIV infection.
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Rostagno A, Calero M, Holton JL, Revesz T, Lashley T, Ghiso J. Association of clusterin with the BRI2-derived amyloid molecules ABri and ADan. Neurobiol Dis 2021; 158:105452. [PMID: 34298087 PMCID: PMC8440498 DOI: 10.1016/j.nbd.2021.105452] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 06/30/2021] [Accepted: 07/18/2021] [Indexed: 10/20/2022] Open
Abstract
Familial British and Danish dementias (FBD and FDD) share striking neuropathological similarities with Alzheimer's disease (AD), including intraneuronal neurofibrillary tangles as well as parenchymal and vascular amyloid deposits. Multiple amyloid associated proteins with still controversial role in amyloidogenesis colocalize with the structurally different amyloid peptides ABri in FBD, ADan in FDD, and Aβ in AD. Genetic variants and plasma levels of one of these associated proteins, clusterin, have been identified as risk factors for AD. Clusterin is known to bind soluble Aβ in biological fluids, facilitate its brain clearance, and prevent its aggregation. The current work identifies clusterin as the major ABri- and ADan-binding protein and provides insight into the biochemical mechanisms leading to the association of clusterin with ABri and ADan deposits. Mirroring findings in AD, the studies corroborate clusterin co-localization with cerebral parenchymal and vascular amyloid deposits in both disorders. Ligand affinity chromatography with downstream Western blot and amino acid sequence analyses unequivocally identified clusterin as the major ABri- and ADan-binding plasma protein. ELISA highlighted a specific saturable binding of clusterin to ABri and ADan with low nanomolar Kd values within the same range as those previously demonstrated for the clusterin-Aβ interaction. Consistent with its chaperone activity, thioflavin T binding assays clearly showed a modulatory effect of clusterin on ABri and ADan aggregation/fibrillization properties. Our findings, together with the known multifunctional activity of clusterin and its modulatory activity on the complex cellular pathways leading to oxidative stress, mitochondrial dysfunction, and the induction of cell death mechanisms - all known pathogenic features of these protein folding disorders - suggests the likelihood of a more complex role and a translational potential for the apolipoprotein in the amelioration/prevention of these pathogenic mechanisms.
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Affiliation(s)
- Agueda Rostagno
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
| | - Miguel Calero
- Instituto de Salud Carlos III, 28029 Madrid, Spain; Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), 28031 Madrid, Spain; Alzheimer's Center Reina Sofia Foundation - CIEN Foundation, 28031 Madrid, Spain
| | - Janice L Holton
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Tamas Revesz
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK; Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Tammaryn Lashley
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK; Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Jorge Ghiso
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA; Department of Psychiatry, New York University School of Medicine, New York, NY 10016, USA.
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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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Wang T, Nuurai P, McDougall C, York PS, Bose U, Degnan BM, Cummins SF. Identification of a female spawn-associated Kazal-type inhibitor from the tropical abalone Haliotis asinina. J Pept Sci 2016; 22:461-70. [PMID: 27352998 DOI: 10.1002/psc.2887] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Revised: 03/26/2016] [Accepted: 03/26/2016] [Indexed: 11/05/2022]
Abstract
Abalone (Haliotis) undergoes a period of reproductive maturation, followed by the synchronous release of gametes, called broadcast spawning. Field and laboratory studies have shown that the tropical species Haliotis asinina undergoes a two-week spawning cycle, thus providing an excellent opportunity to investigate the presence of endogenous spawning-associated peptides. In female H. asinina, we have isolated a peptide (5145 Da) whose relative abundance in hemolymph increases substantially just prior to spawning and is still detected using reverse-phase high-performance liquid chromatography chromatograms up to 1-day post-spawn. We have isolated this peptide from female hemolymph as well as samples prepared from the gravid female gonad, and demonstrated through comparative sequence analysis that it contains features characteristic of Kazal-type proteinase inhibitors (KPIs). Has-KPI is expressed specifically within the gonad of adult females. A recombinant Has-KPI was generated using a yeast expression system. The recombinant Has-KPI does not induce premature spawning of female H. asinina when administered intramuscularly. However it displays homomeric aggregations and interaction with at least one mollusc-type neuropeptide (LRDFVamide), suggesting a role for it in regulating neuropeptide endocrine communication. This research provides new understanding of a peptide that can regulate reproductive processes in female abalone, which has the potential to lead to the development of greater control over abalone spawning. The findings also highlight the need to further explore abalone reproduction to clearly define a role for novel spawning-associated peptide in sexual maturation and spawning. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.
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Affiliation(s)
- Tianfang Wang
- Faculty of Science, Health and Education, University of the Sunshine Coast, Maroochydore, QLD, 4558, Australia
| | - Parinyaporn Nuurai
- Faculty of Allied Health Sciences, Burapha University, Chonburi, 20131, Thailand
| | - Carmel McDougall
- School of Biological Sciences, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Patrick S York
- School of Biological Sciences, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Utpal Bose
- Faculty of Science, Health and Education, University of the Sunshine Coast, Maroochydore, QLD, 4558, Australia
| | - Bernard M Degnan
- School of Biological Sciences, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Scott F Cummins
- Faculty of Science, Health and Education, University of the Sunshine Coast, Maroochydore, QLD, 4558, Australia
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Guitart K, Loers G, Buck F, Bork U, Schachner M, Kleene R. Improvement of neuronal cell survival by astrocyte-derived exosomes under hypoxic and ischemic conditions depends on prion protein. Glia 2016; 64:896-910. [PMID: 26992135 DOI: 10.1002/glia.22963] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 12/18/2015] [Indexed: 02/05/2023]
Abstract
Prion protein (PrP) protects neural cells against oxidative stress, hypoxia, ischemia, and hypoglycemia. In the present study we confirm that cultured PrP-deficient neurons are more sensitive to oxidative stress than wild-type neurons and present the novel findings that wild-type, but not PrP-deficient astrocytes protect wild-type cerebellar neurons against oxidative stress and that exosomes released from stressed wild-type, but not from stressed PrP-deficient astrocytes reduce neuronal cell death induced by oxidative stress. We show that neuroprotection by exosomes of stressed astrocytes depends on exosomal PrP but not on neuronal PrP and that astrocyte-derived exosomal PrP enters into neurons, suggesting neuronal uptake of astrocyte-derived exosomes. Upon exposure of wild-type astrocytes to hypoxic or ischemic conditions PrP levels in exosomes were increased. By mass spectrometry and Western blot analysis, we detected increased levels of 37/67 kDa laminin receptor, apolipoprotein E and the ribosomal proteins S3 and P0, and decreased levels of clusterin/apolipoprotein J in exosomes from wild-type astrocytes exposed to oxygen/glucose deprivation relative to exosomes from astrocytes maintained under normoxic conditions. The levels of these proteins were not altered in exosomes from stressed PrP-deficient astrocytes relative to unstressed PrP-deficient astrocytes. These results indicate that PrP in astrocytes is a sensor for oxidative stress and mediates beneficial cellular responses, e.g. release of exosomes carrying PrP and other molecules, resulting in improved survival of neurons under hypoxic and ischemic conditions.
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Affiliation(s)
- Kathrin Guitart
- Zentrum Für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Gabriele Loers
- Zentrum Für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Friedrich Buck
- Institut Für Klinische Chemie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Ute Bork
- Zentrum Für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Melitta Schachner
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey
- Center for Neuroscience, Shantou University Medical College, Shantou, Guangdong, China
| | - Ralf Kleene
- Zentrum Für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
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Beeg M, Stravalaci M, Romeo M, Carrá AD, Cagnotto A, Rossi A, Diomede L, Salmona M, Gobbi M. Clusterin Binds to Aβ1-42 Oligomers with High Affinity and Interferes with Peptide Aggregation by Inhibiting Primary and Secondary Nucleation. J Biol Chem 2016; 291:6958-66. [PMID: 26884339 DOI: 10.1074/jbc.m115.689539] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Indexed: 11/06/2022] Open
Abstract
The aggregation of amyloid β protein (Aβ) is a fundamental pathogenic mechanism leading to the neuronal damage present in Alzheimer disease, and soluble Aβ oligomers are thought to be a major toxic culprit. Thus, better knowledge and specific targeting of the pathways that lead to these noxious species may result in valuable therapeutic strategies. We characterized some effects of the molecular chaperone clusterin, providing new and more detailed evidence of its potential neuroprotective effects. Using a classical thioflavin T assay, we observed a dose-dependent inhibition of the aggregation process. The global analysis of time courses under different conditions demonstrated that clusterin has no effect on the elongation rate but mainly interferes with the nucleation processes (both primary and secondary), reducing the number of nuclei available for further fibril growth. Then, using a recently developed immunoassay based on surface plasmon resonance, we obtained direct evidence of a high-affinity (KD= 1 nm) interaction of clusterin with biologically relevant Aβ1-42oligomers, selectively captured on the sensor chip. Moreover, with the same technology, we observed that substoichiometric concentrations of clusterin prevent oligomer interaction with the antibody 4G8, suggesting that the chaperone shields hydrophobic residues exposed on the oligomeric assemblies. Finally, we found that preincubation with clusterin antagonizes the toxic effects of Aβ1-42oligomers, as evaluated in a recently developedin vivomodel inCaenorhabditis elegans.These data substantiate the interaction of clusterin with biologically active regions exposed on nuclei/oligomers of Aβ1-42, providing a molecular basis for the neuroprotective effects of the chaperone.
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Affiliation(s)
- Marten Beeg
- From the Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy
| | - Matteo Stravalaci
- From the Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy
| | - Margherita Romeo
- From the Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy
| | - Arianna Dorotea Carrá
- From the Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy
| | - Alfredo Cagnotto
- From the Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy
| | - Alessandro Rossi
- From the Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy
| | - Luisa Diomede
- From the Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy
| | - Mario Salmona
- From the Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy
| | - Marco Gobbi
- From the Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milan, Italy
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Huang L, Liu X, Cheng B, Huang K. How our bodies fight amyloidosis: effects of physiological factors on pathogenic aggregation of amyloidogenic proteins. Arch Biochem Biophys 2015; 568:46-55. [PMID: 25615529 DOI: 10.1016/j.abb.2015.01.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 01/08/2015] [Accepted: 01/11/2015] [Indexed: 12/15/2022]
Abstract
The process of protein aggregation from soluble amyloidogenic proteins to insoluble amyloid fibrils plays significant roles in the onset of over 30 human amyloidogenic diseases, such as Prion disease, Alzheimer's disease and type 2 diabetes mellitus. Amyloid deposits are commonly found in patients suffered from amyloidosis; however, such deposits are rarely seen in healthy individuals, which may be largely attributed to the self-regulation in vivo. A vast number of physiological factors have been demonstrated to directly affect the process of amyloid formation in vivo. In this review, physiological factors that influence amyloidosis, including biological factors (chaperones, natural antibodies, enzymes, lipids and saccharides) and physicochemical factors (metal ions, pH environment, crowding and pressure, etc.), together with the mechanisms underlying these proteostasis effects, are summarized.
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Affiliation(s)
- Lianqi Huang
- Tongji School of Pharmacy, Huazhong University of Science and Technology, Wuhan, Hubei 430030, PR China
| | - Xinran Liu
- Tongji School of Pharmacy, Huazhong University of Science and Technology, Wuhan, Hubei 430030, PR China
| | - Biao Cheng
- Department of Pharmacy, Central Hospital of Wuhan, Wuhan, Hubei 430014, PR China
| | - Kun Huang
- Tongji School of Pharmacy, Huazhong University of Science and Technology, Wuhan, Hubei 430030, PR China; Centre for Biomedicine Research, Wuhan Institute of Biotechnology, Wuhan, Hubei 430075, PR China.
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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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10
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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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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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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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Chapter 9: Oxidative stress in malignant progression: The role of Clusterin, a sensitive cellular biosensor of free radicals. Adv Cancer Res 2010; 104:171-210. [PMID: 19878777 DOI: 10.1016/s0065-230x(09)04009-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Clusterin/Apolipoprotein J (CLU) gene is expressed in most human tissues and encodes for two protein isoforms; a conventional heterodimeric secreted glycoprotein and a truncated nuclear form. CLU has been functionally implicated in several physiological processes as well as in many pathological conditions including ageing, diabetes, atherosclerosis, degenerative diseases, and tumorigenesis. A major link of all these, otherwise unrelated, diseases is that they are characterized by increased oxidative injury due to impaired balance between production and disposal of reactive oxygen or nitrogen species. Besides the aforementioned diseases, CLU gene is differentially regulated by a wide variety of stimuli which may also promote the production of reactive species including cytokines, interleukins, growth factors, heat shock, radiation, oxidants, and chemotherapeutic drugs. Although at low concentration reactive species may contribute to normal cell signaling and homeostasis, at increased amounts they promote genomic instability, chronic inflammation, lipid oxidation, and amorphous aggregation of target proteins predisposing thus cells for carcinogenesis or other age-related disorders. CLU seems to intervene to these processes due to its small heat-shock protein-like chaperone activity being demonstrated by its property to inhibit protein aggregation and precipitation, a main feature of oxidant injury. The combined presence of many potential regulatory elements in the CLU gene promoter, including a Heat-Shock Transcription Factor-1 and an Activator Protein-1 element, indicates that CLU gene is an extremely sensitive cellular biosensor of even minute alterations in the cellular oxidative load. This review focuses on CLU regulation by oxidative injury that is the common molecular link of most, if not all, pathological conditions where CLU has been functionally implicated.
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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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Nerelius C, Gustafsson M, Nordling K, Larsson A, Johansson J. Anti-amyloid activity of the C-terminal domain of proSP-C against amyloid beta-peptide and medin. Biochemistry 2009; 48:3778-86. [PMID: 19281242 DOI: 10.1021/bi900135c] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Amyloid fibrils are found in approximately 25 different diseases, including Alzheimer's disease. Lung surfactant protein C (SP-C) forms fibrils in association with pulmonary disease. It was recently found that the C-terminal domain of proSP-C (CTC), which is localized to the endoplasmic reticulum (ER) lumen, protects the transmembrane (TM) part of (pro)SP-C from aggregation into amyloid until it has a folded into an alpha-helix. CTC appears to have a more general anti-amyloid effect by also acting on TM regions of other proteins. Here we investigate interactions of CTC with the amyloid beta-peptide (Abeta) associated with Alzheimer's disease and medin, a peptide that forms fibrils in the most common form of human amyloid. CTC prevents fibril formation in Abeta and medin and forms a complex with Abeta oligomers, as judged by size-exclusion chromatography and electrospray ionization mass spectrometry. These data suggest that CTC functions as a chaperone that acts preferentially against unfolded TM segments and structural motifs found during amyloid fibril formation, a mechanism that may be exploited in forming a basis for future anti-amyloid therapy.
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Affiliation(s)
- Charlotte Nerelius
- Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, The Biomedical Centre, 751 23 Uppsala, Sweden
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17
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Johansson H, Nerelius C, Nordling K, Johansson J. Preventing amyloid formation by catching unfolded transmembrane segments. J Mol Biol 2009; 389:227-9. [PMID: 19376131 DOI: 10.1016/j.jmb.2009.04.021] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Revised: 03/19/2009] [Accepted: 04/10/2009] [Indexed: 10/20/2022]
Abstract
A subset of protein misfolding diseases, including, for example, Alzheimer's disease, is associated with the formation of highly insoluble amyloid fibrils with a beta-sheet structure. The amyloidogenic human lung surfactant protein C (SP-C) is generated from SP-C precursor, which has a C-terminal domain (CTC) that prevents SP-C amyloid fibril formation. Analysis of the substrate specificity of CTC reveals that it binds to all amino acid residues that promote membrane insertion, provided that they are in a nonhelical conformation. In line with this unexpectedly general substrate specificity, the anti-amyloid function of CTC extends to a transmembrane segment other than that of (pro)SP-C, namely, the amyloid beta-peptide associated with Alzheimer's disease. These findings indicate that CTC is the first known chaperone to be directed towards nonhelical transmembrane segments and that it may be employed for the development of new diagnostics or anti-amyloid therapies.
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Affiliation(s)
- H Johansson
- Department of Anatomy, Physiology, and Biochemistry, SLU, The Biomedical Center, 75123 Uppsala, Sweden
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18
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Xu F, Karnaukhova E, Vostal JG. Human cellular prion protein interacts directly with clusterin protein. Biochim Biophys Acta Mol Basis Dis 2008; 1782:615-20. [DOI: 10.1016/j.bbadis.2008.08.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Revised: 07/25/2008] [Accepted: 08/05/2008] [Indexed: 02/07/2023]
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19
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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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20
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Janig E, Haslbeck M, Aigelsreiter A, Braun N, Unterthor D, Wolf P, Khaskhely NM, Buchner J, Denk H, Zatloukal K. Clusterin associates with altered elastic fibers in human photoaged skin and prevents elastin from ultraviolet-induced aggregation in vitro. THE AMERICAN JOURNAL OF PATHOLOGY 2007; 171:1474-82. [PMID: 17872975 PMCID: PMC2043509 DOI: 10.2353/ajpath.2007.061064] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Clusterin is a secreted glycoprotein with stress-induced expression in various diseased and aged tissues. It shares basic features with small heat shock proteins because it may stabilize proteins in a folding-competent state. Besides its presence in all human body fluids, clusterin associates with altered extracellular matrix proteins, such as beta-amyloid in Alzheimer senile plaques in the brain. Because dermal connective tissue alterations occur because of aging and UV radiation, we explored the occurrence of clusterin in young, aged, and sun-exposed human skin. Immunohistochemical analysis showed that clusterin is constantly associated with altered elastic fibers in aged human skin. Elastotic material of sun-damaged skin (solar elastosis), in particular, revealed a strong staining for clusterin. Because of the striking co-localization of clusterin with abnormal elastic material, we investigated the interaction of clusterin with elastin in vitro. A chaperone assay was established in which elastin was denatured by UV irradiation in the absence or presence of clusterin. This assay demonstrated that clusterin exerted a chaperone-like activity and effectively inhibited UV-induced aggregation of elastin. The interaction of both proteins was further analyzed by electron microscopy, size exclusion chromatography, and mass spectrometry, in which clusterin was found in a stable complex with elastin after UV exposure.
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Affiliation(s)
- Elke Janig
- Institute of Pathology, Medical University of Graz, Graz, Austria
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21
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Yerbury JJ, Poon S, Meehan S, Thompson B, Kumita JR, Dobson CM, Wilson MR. The extracellular chaperone clusterin influences amyloid formation and toxicity by interacting with prefibrillar structures. FASEB J 2007; 21:2312-22. [PMID: 17412999 DOI: 10.1096/fj.06-7986com] [Citation(s) in RCA: 238] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Clusterin is an extracellular chaperone present in all disease-associated extracellular amyloid deposits, but its roles in amyloid formation and protein deposition in vivo are poorly understood. The current study initially aimed to characterize the effects of clusterin on amyloid formation in vitro by a panel of eight protein substrates. Two of the substrates (Alzheimer's beta peptide and a PI3-SH3 domain) were then used in further experiments to examine the effects of clusterin on amyloid cytotoxicity and to probe the mechanism of clusterin action. We show that clusterin exerts potent effects on amyloid formation, the nature and extent of which vary greatly with the clusterin:substrate ratio, and provide evidence that these effects are exerted via interactions with prefibrillar species that share common structural features. Proamyloidogenic effects of clusterin appear to be restricted to conditions in which the substrate protein is present at a very large molar excess; under these same conditions, clusterin coincorporates with substrate protein into insoluble aggregates. However, when clusterin is present at much higher but still substoichiometric levels (e.g., a molar ratio of clusterin:substrate=1:10), it potently inhibits amyloid formation and provides substantial cytoprotection. These findings suggest that clusterin is an important element in the control of extracellular protein misfolding.
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Affiliation(s)
- Justin J Yerbury
- School of Biological Sciences, University of Wollongong, Wollongong, Australia
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22
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Trougakos IP, Gonos ES. Regulation of clusterin/apolipoprotein J, a functional homologue to the small heat shock proteins, by oxidative stress in ageing and age-related diseases. Free Radic Res 2007; 40:1324-34. [PMID: 17090421 DOI: 10.1080/10715760600902310] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Clusterin/apolipoprotein J (CLU) gene has a nearly ubiquitous expression pattern in human tissues. The two main CLU protein isoforms in human cells include the conventional glycosylated secreted heterodimer (sCLU) and a truncated nuclear form (nCLU). CLU has been implicated in various physiological processes and in many severe physiological disturbance states including ageing, cancer progression, vascular damage, diabetes, kidney and neuron degeneration. Although unrelated in their etiology and clinical manifestation, these diseases represent states of increased oxidative stress, which in turn, promotes amorphous aggregation of target proteins, increased genomic instability and high rates of cellular death. Among the various properties attributed to CLU so far, those mostly investigated and invariably appreciated are its small heat shock proteins-like chaperone activity and its involvement in cell death regulation, which are both directly correlated to the main features of oxidant injury. Moreover, the presence of both a heat shock transcription factor-1 and an activator protein-1 element in the CLU gene promoter indicate that CLU gene can be an extremely sensitive biosensor to reactive oxygen species. This review emphasizes on CLU gene regulation by oxidative stress that is the common link between all pathological conditions where CLU has been implicated.
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Affiliation(s)
- Ioannis P Trougakos
- Laboratory of Molecular & Cellular Ageing, Institute of Biological Research & Biotechnology, National Hellenic Research Foundation, Athens, Greece
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23
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Sasaki K, Doh-ura K, Ironside J, Mabbott N, Iwaki T. Clusterin expression in follicular dendritic cells associated with prion protein accumulation. J Pathol 2006; 209:484-91. [PMID: 16767691 DOI: 10.1002/path.2009] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Peripheral accumulation of abnormal prion protein (PrP) in variant Creutzfeldt-Jakob disease and some animal models of transmissible spongiform encephalopathies (TSEs) may occur in the lymphoreticular system. Within the lymphoid tissues, abnormal PrP accumulation occurs on follicular dendritic cells (FDCs). Clusterin (apolipoprotein J) has been recognized as one of the molecules associated with PrP in TSEs, and clusterin expression is increased in the central nervous system where abnormal PrP deposition has occurred. We therefore examined peripheral clusterin expression in the context of PrP accumulation on FDCs in a range of human and experimental TSEs. PrP was detected immunohistochemically on tissue sections using a novel highly sensitive method involving detergent autoclaving pretreatment. A dendritic network pattern of clusterin immunoreactivity in lymphoid follicles was observed in association with the abnormal PrP on FDCs. The increased clusterin immunoreactivity appeared to correlate with the extent of PrP deposition, irrespective of the pathogen strains, host mouse strains or various immune modifications. The observed co-localization and correlative expression of these proteins suggested that clusterin might be directly associated with abnormal PrP. Indeed, clusterin immunoreactivity in association with PrP was retained after FDC depletion. Together these data suggest that clusterin may act as a chaperone-like molecule for PrP and play an important role in TSE pathogenesis.
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Affiliation(s)
- K Sasaki
- Department of Neuropathology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
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24
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Ecroyd H, Belghazi M, Dacheux JL, Gatti JL. The epididymal soluble prion protein forms a high-molecular-mass complex in association with hydrophobic proteins. Biochem J 2006; 392:211-9. [PMID: 16029166 PMCID: PMC1317680 DOI: 10.1042/bj20050459] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We have shown previously that a 'soluble' form of PrP (prion protein), not associated with membranous vesicles, exists in the male reproductive fluid [Ecroyd, Sarradin, Dacheux and Gatti (2004) Biol. Reprod. 71, 993-1001]. Attempts to purify this 'soluble' PrP indicated that it behaves like a high-molecular-mass complex of more than 350 kDa and always co-purified with the same set of proteins. The main associated proteins were sequenced by MS and were found to match to clusterin (apolipoprotein J), BPI (bacterial permeability-increasing protein), carboxylesterase-like urinary excreted protein (cauxin), beta-mannosidase and beta-galactosidase. Immunoblotting and enzymatic assay confirmed the presence of clusterin and a cauxin-like protein and showed that a 17 kDa hydrophobic epididymal protein was also associated with this complex. These associated proteins were not separated by a high ionic strength treatment but were by 2-mercaptoethanol, probably due to its action on reducing disulphide bonds that maintain the interaction of components of the complex. Our results suggest that the associated PrP retains its GPI (glycosylphosphatidylinositol) anchor, in contrast with brain-derived PrP, and that it is resistant to cleavage by phosphatidylinositol-specific phospholipase C. Based on these results, the identity of the associated proteins and the overall biochemical properties of this protein ensemble, we suggest that 'soluble' PrP can form protein complexes that are maintained by hydrophobic interactions, in a similar manner to lipoprotein vesicles or micellar complexes.
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Affiliation(s)
- Heath Ecroyd
- *Gamète Male et Fertilité, Institut National de la Recherche Agronomique, INRA-Nouzilly, 37380 Monnaie, France
| | - Maya Belghazi
- †Service de Spectrométrie de Masse pour la Protéomique, UMR 6175, INRA-CNRS-Haras Nationaux-Université de Tours, Station de Physiologie de la Reproduction et des Comportements, Institut National de la Recherche Agronomique, INRA-Nouzilly, 37380 Monnaie, France
| | - Jean-Louis Dacheux
- *Gamète Male et Fertilité, Institut National de la Recherche Agronomique, INRA-Nouzilly, 37380 Monnaie, France
| | - Jean-Luc Gatti
- *Gamète Male et Fertilité, Institut National de la Recherche Agronomique, INRA-Nouzilly, 37380 Monnaie, France
- To whom correspondence should be addressed (email )
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25
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Kempster S, Collins ME, Aronow BJ, Simmons M, Green RB, Edington N. Clusterin shortens the incubation and alters the histopathology of bovine spongiform encephalopathy in mice. Neuroreport 2004; 15:1735-8. [PMID: 15257138 DOI: 10.1097/01.wnr.0000134990.97051.22] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Clusterin accumulates in significant quantity in prion protein lesions associated with bovine spongiform encephalopathy (BSE) and we therefore sought to elucidate its ability to alter BSE pathogenesis and incubation time by comparison of wild type C57BL/6J mice and clusterin knock out (ko) mice. The ko mice had a 40 day increase in mean incubation time compared to wild type mice. PrP deposition in the medulla was less aggregated in clusterin knock out mice when compared to wild type BSE infected mice and a more marked astrocytosis, as determined by GFAP staining, was evident. The vacuolation profiles did not differ between the two strains of mice. Taken together these results suggest that clusterin alters the extracellular deposition of PrP(BSE) and accelerates BSE pathogenesis.
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Affiliation(s)
- S Kempster
- Department of Pathology and Infectious Diseases, Royal Veterinary College, Royal College Street, London NW1 0TU, UK.
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26
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Freixes M, Puig B, Rodríguez A, Torrejón-Escribano B, Blanco R, Ferrer I. Clusterin solubility and aggregation in Creutzfeldt-Jakob disease. Acta Neuropathol 2004; 108:295-301. [PMID: 15235804 DOI: 10.1007/s00401-004-0891-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2004] [Revised: 05/06/2004] [Accepted: 05/06/2004] [Indexed: 10/26/2022]
Abstract
Prion protein (PrPC) is a glycolipid-anchored cell membrane syaloglycoprotein that localizes in presynaptic membranes. PrP has the property of aggregating into amyloid fibrils and being deposited in the brains in cases with transmissible encephalopathies (TSEs), when PrPC is converted into abnormal protease-resistant PrP (PrPRES). Clusterin is a heterodimeric glycoprotein, the expression of which is enhanced in astrocytes in association with punctate-type PrPRES deposits during TSE progression. In addition, clusterin co-localizes in PrPRES plaques in several human TSEs, including Creutzfeldt-Jakob disease (CJD). Clusterin is up-regulated in the cerebral cortex and cerebellum in CJD as revealed by DNA micro-array technology. Clusterin expression was examined in seven sporadic cases of CJD (codon 129 genotype, PrP type: 4 MM1, 1 MV1, 1 MV2, 1 VV2) and three age-matched controls by immunohistochemistry, Western blotting and solubility. In addition to small punctate clusterin deposition in the neuropil, single- and double-labeling immunohistochemistry disclosed clusterin localization in PrPRES plaques, which predominated in the cerebellum of cases MV1, MV2 and VV2. Moreover, clusterin in plaques, but not punctate clusterin deposits, was resistant to protease digestion, as revealed in tissue sections pre-incubated with proteinase K. Clusterin in CJD, but not clusterin in control brains, was partially resistant to protease digestion in Western blots of total brain homogenates immunostained with anti-clusterin antibodies, which were processed in parallel with Western blots to PrP, without and with pre-incubation with proteinase K. Protein aggregation was analyzed in brain homogenates subjected to several solvents. PrP was recovered in the deoxycholate fraction in control and CJD cases, but in the SDS fraction only in CJD, thus indicating differences in PrP solubility between CJD and controls. Clusterin was recovered in the cytosolic, deoxycholate and SDS fraction in both CJD and control cases, but only clusterin from CJD was recovered in the urea-soluble fraction and, especially, in the remaining pellet. These findings demonstrate the capacity of clusterin to form aggregates and interact with PrPRES aggregates. The implications of this property are not known, but it can be suggested that clusterin participates in PrP clustering and sequestration, thus modifying PrP toxicity in CJD.
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Affiliation(s)
- M Freixes
- Institut de Neuropatologia, Servei Anatomia Patològica, Hospital de Bellvitge, carrer Feixa Llarga sn, 08907 Hospitalet de Llobregat, Spain
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27
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Matsuda A, Itoh Y, Koshikawa N, Akizawa T, Yana I, Seiki M. Clusterin, an abundant serum factor, is a possible negative regulator of MT6-MMP/MMP-25 produced by neutrophils. J Biol Chem 2003; 278:36350-7. [PMID: 12860995 DOI: 10.1074/jbc.m301509200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
MT6-MMP/MMP-25 is the latest member of the membrane-type matrix metalloproteinase (MT-MMP) subgroup in the MMP family and is expressed in neutrophils and some brain tumors. The proteolytic activity of MT6-MMP has been studied using recombinant catalytic fragments and shown to degrade several components of the extracellular matrix. However, the activity is possibly modulated further by the C-terminal hemopexin-like domain, because some MMPs are known to interact with other proteins through this domain. To explore the possible function of this domain, we purified a recombinant MT6-MMP with the hemopexin-like domain as a soluble form using a Madin-Darby canine kidney cell line as a producer. Mature and soluble MT6-MMP processed at the furin motif was purified as a 45-kDa protein together with a 46-kDa protein having a single cleavage in the hemopexin-like domain. Interestingly, 73- and 70-kDa proteins were co-purified with the soluble MT6-MMP by forming stable complexes. They were identified as clusterin, a major component of serum, by N-terminal amino acid sequencing. MT1-MMP that also has a hemopexin-like domain did not form a complex with clusterin. MT6-MMP forming a complex with clusterin was detected in human neutrophils as well. The enzyme activity of the soluble MT6-MMP was inactive in the clusterin complex. Purified clusterin was inhibitory against the activity of soluble MT6-MMP. On the other hand, it had no effect on the activities of MMP-2 and soluble MT1-MMP. Because clusterin is an abundant protein in the body fluid in tissues, it may act as a negative regulator of MT6-MMP in vivo.
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Affiliation(s)
- Akira Matsuda
- Division of Cancer Cell Research, Institute of Medical Science, the University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
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28
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Debure L, Vayssiere JL, Rincheval V, Loison F, Le Drean Y, Michel D. Intracellular clusterin causes juxtanuclear aggregate formation and mitochondrial alteration. J Cell Sci 2003; 116:3109-21. [PMID: 12799419 DOI: 10.1242/jcs.00619] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Clusterin is a puzzling protein upregulated in many diseased tissues, presented as either a survival or a death protein. The role of clusterin might depend on the final maturation and localization of the protein, which can be secreted or reside inside cells, either after in situ synthesis or uptake of extracellular clusterin. We studied the biological effects of intracellular clusterin and observed that clusterin forms containing the alpha-chain region strongly accumulated in an ubiquitinated form in juxtanuclear aggregates meeting the main criterions of aggresomes and leading to profound alterations of the mitochondrial network. The viability of cells transfected by intracellular forms of clusterin was improved by overexpression of Bcl-2, and caspase inhibition was capable of rescuing cells expressing clusterin, which presented an altered mitochondrial permeability. We propose that, although it might be an inherently pro-survival and anti-apoptotic protein expressed by cells under stress in an attempt to protect themselves, clusterin can become highly cytotoxic when accumulated in the intracellular compartment. This activity might reconcile the opposite purported influences of clusterin on cell survival and explain how clusterin can be causally involved in neurodegeneration.
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Affiliation(s)
- Laure Debure
- Information et Programmation Cellulaire, UMR6026 CNRS-Université de Rennes 1, Campus de Beaulieu, Bat 13, 35042 Rennes Cedex, France.
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29
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Abstract
Clusterin/Apolipoprotein J (ApoJ) is a heterodimeric highly conserved secreted glycoprotein being expressed in a wide variety of tissues and found in all human fluids. Despite being cloned since 1989, no genuine function has been attributed to ApoJ so far. The protein has been reportedly implicated in several diverse physiological processes such as sperm maturation, lipid transportation, complement inhibition, tissue remodeling, membrane recycling, cell-cell and cell-substratum interactions, stabilization of stressed proteins in a folding-competent state and promotion or inhibition of apoptosis. ApoJ gene is differentially regulated by cytokines, growth factors and stress-inducing agents, while another defining prominent and intriguing ApoJ feature is its upregulation in many severe physiological disturbances states and in several neurodegenerative conditions mostly related to advanced aging. Moreover, ApoJ accumulates during the viable growth arrested cellular state of senescence, that is thought to contribute to aging and to tumorigenesis suppression; paradoxically ApoJ is also upregulated in several cases of in vivo cancer progression and tumor formation. This review focuses on the reported data related to ApoJ cell-type and signal specific regulation, function and site of action in normal and cancer cells. We discuss the role of ApoJ during cellular senescence and tumorigenesis, especially under the light of the recently demonstrated various ApoJ intracellular protein forms and their interaction with molecules involved in signal transduction and DNA repair, raising the possibility that its overexpression during cellular senescence might cause a predisposition to cancer.
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Affiliation(s)
- Ioannis P Trougakos
- Laboratory of Molecular & Cellular Aging, Institute of Biological Research and Biotechnology, National Hellenic Research Foundation, 48 Vas Constantinou Avenue, Athens 11635, Greece
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30
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Hatters DM, Wilson MR, Easterbrook-Smith SB, Howlett GJ. Suppression of apolipoprotein C-II amyloid formation by the extracellular chaperone, clusterin. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:2789-94. [PMID: 12047389 DOI: 10.1046/j.1432-1033.2002.02957.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The effect of the extracellular chaperone, clusterin, on amyloid fibril formation by lipid-free human apolipoprotein C-II (apoC-II) was investigated. Sub-stoichiometric levels of clusterin, derived from either plasma or semen, potently inhibit amyloid formation by apoC-II. Inhibition is dependent on apoC-II concentration, with more effective inhibition by clusterin observed at lower concentrations of apoC-II. The average sedimentation coefficient of apoC-II fibrils formed from apoC-II (0.3 mg.mL-1) is reduced by coincubation with clusterin (10 microg x mL(-1)). In contrast, addition of clusterin (0.1 mg x mL(-1)) to preformed apoC-II amyloid fibrils (0.3 mg x mL(-1)) does not affect the size distribution after 2 days. This sedimentation velocity data suggests that clusterin inhibits fibril growth but does not promote fibril dissociation. Electron micrographs indicate similar morphologies for amyloid fibrils formed in the presence or absence of clusterin. The substoichiometric nature of the inhibition suggests that clusterin interacts with transient amyloid nuclei leading to dissociation of the monomeric subunits. We propose a general role for clusterin in suppressing the growth of extracellular amyloid.
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Affiliation(s)
- Danny M Hatters
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Victoria, Australia
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31
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Gauczynski S, Hundt C, Leucht C, Weiss S. Interaction of prion proteins with cell surface receptors, molecular chaperones, and other molecules. ADVANCES IN PROTEIN CHEMISTRY 2002; 57:229-72. [PMID: 11447692 DOI: 10.1016/s0065-3233(01)57024-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- S Gauczynski
- Laboratorium für Molekulare, Biologie-Genzentrum-Institut für Biochemie der LMU München, D-81377 Munich, Germany
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32
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Affiliation(s)
- M R Wilson
- Dept of Biological Sciences, University of Wollongong, Northfields Avenue, Wollongong, NSW Australia 2522.
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