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Moncaster JA, Moir RD, Burton MA, Chadwick O, Minaeva O, Alvarez VE, Ericsson M, Clark JI, McKee AC, Tanzi RE, Goldstein LE. Alzheimer's disease amyloid-β pathology in the lens of the eye. Exp Eye Res 2022; 221:108974. [PMID: 35202705 PMCID: PMC9873124 DOI: 10.1016/j.exer.2022.108974] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 01/31/2022] [Accepted: 02/02/2022] [Indexed: 01/26/2023]
Abstract
Neuropathological hallmarks of Alzheimer's disease (AD) include pathogenic accumulation of amyloid-β (Aβ) peptides and age-dependent formation of amyloid plaques in the brain. AD-associated Aβ neuropathology begins decades before onset of cognitive symptoms and slowly progresses over the course of the disease. We previously reported discovery of Aβ deposition, β-amyloidopathy, and co-localizing supranuclear cataracts (SNC) in lenses from people with AD, but not other neurodegenerative disorders or normal aging. We confirmed AD-associated Aβ molecular pathology in the lens by immunohistopathology, amyloid histochemistry, immunoblot analysis, epitope mapping, immunogold electron microscopy, quantitative immunoassays, and tryptic digest mass spectrometry peptide sequencing. Ultrastructural analysis revealed that AD-associated Aβ deposits in AD lenses localize as electron-dense microaggregates in the cytoplasm of supranuclear (deep cortex) fiber cells. These Aβ microaggregates also contain αB-crystallin and scatter light, thus linking Aβ pathology and SNC phenotype expression in the lenses of people with AD. Subsequent research identified Aβ lens pathology as the molecular origin of the distinctive cataracts associated with Down syndrome (DS, trisomy 21), a chromosomal disorder invariantly associated with early-onset Aβ accumulation and Aβ amyloidopathy in the brain. Investigation of 1249 participants in the Framingham Eye Study found that AD-associated quantitative traits in brain and lens are co-heritable. Moreover, AD-associated lens traits preceded MRI brain traits and cognitive deficits by a decade or more and predicted future AD. A genome-wide association study of bivariate outcomes in the same subjects identified a new AD risk factor locus in the CTNND2 gene encoding δ-catenin, a protein that modulates Aβ production in brain and lens. Here we report identification of AD-related human Aβ (hAβ) lens pathology and age-dependent SNC phenotype expression in the Tg2576 transgenic mouse model of AD. Tg2576 mice express Swedish mutant human amyloid precursor protein (APP-Swe), accumulate hAβ peptides and amyloid pathology in the brain, and exhibit cognitive deficits that slowly progress with increasing age. We found that Tg2576 trangenic (Tg+) mice, but not non-transgenic (Tg-) control mice, also express human APP, accumulate hAβ peptides, and develop hAβ molecular and ultrastructural pathologies in the lens. Tg2576 Tg+ mice exhibit age-dependent Aβ supranuclear lens opacification that recapitulates lens pathology and SNC phenotype expression in human AD. In addition, we detected hAβ in conditioned medium from lens explant cultures prepared from Tg+ mice, but not Tg- control mice, a finding consistent with constitutive hAβ generation in the lens. In vitro studies showed that hAβ promoted mouse lens protein aggregation detected by quasi-elastic light scattering (QLS) spectroscopy. These results support mechanistic (genotype-phenotype) linkage between Aβ pathology and AD-related phenotypes in lens and brain. Collectively, our findings identify Aβ pathology as the shared molecular etiology of two age-dependent AD-related cataracts associated with two human diseases (AD, DS) and homologous murine cataracts in the Tg2576 transgenic mouse model of AD. These results represent the first evidence of AD-related Aβ pathology outside the brain and point to lens Aβ as an optically-accessible AD biomarker for early detection and longitudinal monitoring of this devastating neurodegenerative disease.
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Affiliation(s)
- Juliet A. Moncaster
- Molecular Aging and Development Laboratory, Boston University School of Medicine, Boston, MA, 02118, USA,Boston University Alzheimer’s Disease Research Center, Boston University School of Medicine, 72 East Concord Street, B-7800 Boston, MA, 02118, USA
| | - Robert D. Moir
- Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA
| | - Mark A. Burton
- Molecular Aging and Development Laboratory, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Oliver Chadwick
- Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA
| | - Olga Minaeva
- Molecular Aging and Development Laboratory, Boston University School of Medicine, Boston, MA, 02118, USA,Boston University Alzheimer’s Disease Research Center, Boston University School of Medicine, 72 East Concord Street, B-7800 Boston, MA, 02118, USA
| | - Victor E. Alvarez
- Boston University Alzheimer’s Disease Research Center, Boston University School of Medicine, 72 East Concord Street, B-7800 Boston, MA, 02118, USA,Edith Nourse Rogers Memorial Veterans’ Hospital, Bedford, MA, 01730, USA
| | - Maria Ericsson
- Electron Microscopy Facility, Harvard Medical School, Boston, MA, 02115, USA
| | - John I. Clark
- Departments of Biological Structure and Ophthalmology, University of Washington, Seattle, WA, 98195, USA
| | - Ann C. McKee
- Boston University Alzheimer’s Disease Research Center, Boston University School of Medicine, 72 East Concord Street, B-7800 Boston, MA, 02118, USA,Edith Nourse Rogers Memorial Veterans’ Hospital, Bedford, MA, 01730, USA
| | - Rudolph E. Tanzi
- Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA
| | - Lee E. Goldstein
- Molecular Aging and Development Laboratory, Boston University School of Medicine, Boston, MA, 02118, USA,Boston University Alzheimer’s Disease Research Center, Boston University School of Medicine, 72 East Concord Street, B-7800 Boston, MA, 02118, USA,Corresponding author. Molecular Aging & Development Laboratory, Boston University, School of Medicine, 670 Albany Street, Boston, MA, 02118, USA. (L.E. Goldstein)
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Chaudhury S, Keegan BM, Blagg BSJ. The role and therapeutic potential of Hsp90, Hsp70, and smaller heat shock proteins in peripheral and central neuropathies. Med Res Rev 2021; 41:202-222. [PMID: 32844464 PMCID: PMC8485878 DOI: 10.1002/med.21729] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 08/11/2020] [Accepted: 08/12/2020] [Indexed: 12/16/2022]
Abstract
Heat shock proteins (Hsps) are molecular chaperones that also play important roles in the activation of the heat shock response (HSR). The HSR is an evolutionary conserved and protective mechanism that is used to counter abnormal physiological conditions, stressors, and disease states, such as those exemplified in cancer and/or neurodegeneration. In normal cells, heat shock factor-1 (HSF-1), the transcription factor that regulates the HSR, remains in a dormant multiprotein complex that is formed upon association with chaperones (Hsp90, Hsp70, etc.), co-chaperones, and client proteins. However, under cellular stress, HSF-1 dissociates from Hsp90 and induces the transcriptional upregulation of Hsp70 to afford protection against the encountered cellular stress. As a consequence of both peripheral and central neuropathies, cellular stress occurs and results in the accumulation of unfolded and/or misfolded proteins, which can be counterbalanced by activation of the HSR. Since Hsp90 is the primary regulator of the HSR, modulation of Hsp90 by small molecules represents an attractive therapeutic approach against both peripheral and central neuropathies.
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Affiliation(s)
- Subhabrata Chaudhury
- Department of Chemistry and Biochemistry, Warren Family Research Center for Drug Discovery and Development, University of Notre Dame, Notre Dame, Indiana, USA
| | - Bradley M Keegan
- Department of Chemistry and Biochemistry, Warren Family Research Center for Drug Discovery and Development, University of Notre Dame, Notre Dame, Indiana, USA
| | - Brian S J Blagg
- Department of Chemistry and Biochemistry, Warren Family Research Center for Drug Discovery and Development, University of Notre Dame, Notre Dame, Indiana, USA
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3
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Webster JM, Darling AL, Uversky VN, Blair LJ. Small Heat Shock Proteins, Big Impact on Protein Aggregation in Neurodegenerative Disease. Front Pharmacol 2019; 10:1047. [PMID: 31619995 PMCID: PMC6759932 DOI: 10.3389/fphar.2019.01047] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 08/19/2019] [Indexed: 12/15/2022] Open
Abstract
Misfolding, aggregation, and aberrant accumulation of proteins are central components in the progression of neurodegenerative disease. Cellular molecular chaperone systems modulate proteostasis, and, therefore, are primed to influence aberrant protein-induced neurotoxicity and disease progression. Molecular chaperones have a wide range of functions from facilitating proper nascent folding and refolding to degradation or sequestration of misfolded substrates. In disease states, molecular chaperones can display protective or aberrant effects, including the promotion and stabilization of toxic protein aggregates. This seems to be dependent on the aggregating protein and discrete chaperone interaction. Small heat shock proteins (sHsps) are a class of molecular chaperones that typically associate early with misfolded proteins. These interactions hold proteins in a reversible state that helps facilitate refolding or degradation by other chaperones and co-factors. These sHsp interactions require dynamic oligomerization state changes in response to diverse cellular triggers and, unlike later steps in the chaperone cascade of events, are ATP-independent. Here, we review evidence for modulation of neurodegenerative disease-relevant protein aggregation by sHsps. This includes data supporting direct physical interactions and potential roles of sHsps in the stewardship of pathological protein aggregates in brain. A greater understanding of the mechanisms of sHsp chaperone activity may help in the development of novel therapeutic strategies to modulate the aggregation of pathological, amyloidogenic proteins. sHsps-targeting strategies including modulators of expression or post-translational modification of endogenous sHsps, small molecules targeted to sHsp domains, and delivery of engineered molecular chaperones, are also discussed.
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Affiliation(s)
- Jack M Webster
- Department of Molecular Medicine, USF Byrd Institute, University of South Florida, Tampa, FL, United States
| | - April L Darling
- Department of Molecular Medicine, USF Byrd Institute, University of South Florida, Tampa, FL, United States
| | - Vladimir N Uversky
- Department of Molecular Medicine, USF Byrd Institute, University of South Florida, Tampa, FL, United States
| | - Laura J Blair
- Department of Molecular Medicine, USF Byrd Institute, University of South Florida, Tampa, FL, United States
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4
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Zhu Z, Reiser G. The small heat shock proteins, especially HspB4 and HspB5 are promising protectants in neurodegenerative diseases. Neurochem Int 2018; 115:69-79. [PMID: 29425965 DOI: 10.1016/j.neuint.2018.02.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 01/24/2018] [Accepted: 02/05/2018] [Indexed: 12/13/2022]
Abstract
Small heat shock proteins (sHsps) are a group of proteins with molecular mass between 12 and 43 kDa. Currently, 11 members of this family have been classified, namely HspB1 to HspB11. HspB1, HspB2, HspB5, HspB6, HspB7, and HspB8, which are expressed in brain have been observed to be related to the pathology of neurodegenerative diseases, including Parkinson's, Alzheimer's, Alexander's disease, multiple sclerosis, and human immunodeficiency virus-associated dementia. Specifically, sHsps interact with misfolding and damaging protein aggregates, like Glial fibrillary acidic protein in AxD, β-amyloid peptides aggregates in Alzheimer's disease, Superoxide dismutase 1 in Amyotrophic lateral sclerosis and cytosine-adenine-guanine/polyglutamine (CAG/PolyQ) in Huntington's disease, Spinocerebellar ataxia type 3, Spinal-bulbar muscular atrophy, to reduce the toxicity or increase the clearance of these protein aggregates. The degree of HspB4 expression in brain is still debated. For neuroprotective mechanisms, sHsps attenuate mitochondrial dysfunctions, reduce accumulation of misfolded proteins, block oxidative/nitrosative stress, and minimize neuronal apoptosis and neuroinflammation, which are molecular mechanisms commonly accepted to mirror the progression and development of neurodegenerative diseases. The increasing incidence of the neurodegenerative diseases enhanced search for effective approaches to rescue neural tissue from degeneration with minimal side effects. sHsps have been found to exert neuroprotective functions. HspB5 has been emphasized to reduce the paralysis in a mouse model of experimental autoimmune encephalomyelitis, providing a therapeutic basis for the disease. In this review, we discuss the current understanding of the properties and the mechanisms of protection orchestrated by sHsps in the nervous system, highlighting the promising therapeutic role of sHsps in neurodegenerative diseases.
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Affiliation(s)
- Zhihui Zhu
- Institut für Inflammation und Neurodegeneration (Neurobiochemie), Otto-von-Guericke-Universität Magdeburg, Medizinische Fakultät, Leipziger Straße 44, 39120 Magdeburg, Germany; College of Medicine, Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Georg Reiser
- Institut für Inflammation und Neurodegeneration (Neurobiochemie), Otto-von-Guericke-Universität Magdeburg, Medizinische Fakultät, Leipziger Straße 44, 39120 Magdeburg, Germany.
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Reddy GB, Reddy PY, Surolia A. Alzheimer's and Danish dementia peptides induce cataract and perturb retinal architecture in rats. Biomol Concepts 2017; 8:45-84. [PMID: 28222009 DOI: 10.1515/bmc-2016-0025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 12/08/2016] [Indexed: 02/08/2023] Open
Abstract
Familial Danish dementias (FDDs) are autosomal dominant neurodegenerative disorders that are associated with visual defects. In some aspects, FDD is similar to Alzheimer's disease (AD)- the amyloid deposits in FDD and AD are made of short peptides: amyloid β (Aβ) in AD and ADan in FDD. Previously, we demonstrated an interaction between the dementia peptides and α-crystallin leading to lens opacification in organ culture due to impaired chaperone activity of α-crystallin. Herein, we report the in vivo effects of ADan and Aβ on the eye. ADan [reduced (ADan-red) and oxidized (ADan-oxi)] and Aβ (Aβ1-40 and Aβ1-42) were injected intravitreally in rats. The onset of cataract was seen after injection of all the peptides, but the cataract matured by 2 weeks in the case of ADan-red, 5 weeks for ADan-oxi and 6 weeks for Aβ1-40, while Aβ1-42 had minimal effect on cataract progression. The severity of cataract is associated with insolubilization and alterations in crystallins and loss of chaperone activity of α-crystallin. Further, disruption of the architecture of the retina was evident from a loss of rhodopsin, increased gliosis, and the thinning of the retina. These results provide a basis for the dominant heredo-otoophthalmo-encephalopathy (HOOE)/FDD syndrome and indicate that ADan peptides are more potent than Aβpeptides in inflicting visual impairment.
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Affiliation(s)
- G Bhanuprakash Reddy
- Biochemistry Division, National Institute of Nutrition, Hyderabad 500007, Telangana, India
| | - P Yadagiri Reddy
- Biochemistry Division, National Institute of Nutrition, Hyderabad, India
| | - Avadhesha Surolia
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru 560012, Karnataka, India
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Kerbage C, Sadowsky CH, Tariot PN, Agronin M, Alva G, Turner FD, Nilan D, Cameron A, Cagle GD, Hartung PD. Detection of Amyloid β Signature in the Lens and Its Correlation in the Brain to Aid in the Diagnosis of Alzheimer's Disease. Am J Alzheimers Dis Other Demen 2015; 30:738-45. [PMID: 24526759 PMCID: PMC10852881 DOI: 10.1177/1533317513520214] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2024]
Abstract
We report the findings from a clinical trial in which a group of patients clinically diagnosed with probable Alzheimer's disease (AD) were discriminated from an age-matched group of healthy volunteers (HVs) with statistical significance (P<.001). The results from 20 patients with AD and 20 HVs were obtained by a Fluorescent Ligand Eye Scanning (FLES) technique that measures a fluorescent signature specific to an exogenous ligand bound to amyloid-β in the lens of the eye. Sensitivity and specificity of 85% and 95%, respectively, have been achieved in predicting clinical diagnosis. Additionally, amyloid brain imaging using florbetapir F18 positron emission tomography shows significant correlation with the results obtained in the eye. Results of the study demonstrate the safety of the FLES system.
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Affiliation(s)
| | - Carl H Sadowsky
- Premiere Research Institute and Nova Southeastern University, West Palm Beach, FL, USA
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Anbarasu K, Sivakumar J. Multidimensional significance of crystallin protein-protein interactions and their implications in various human diseases. Biochim Biophys Acta Gen Subj 2015; 1860:222-33. [PMID: 26365509 DOI: 10.1016/j.bbagen.2015.09.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 08/28/2015] [Accepted: 09/08/2015] [Indexed: 02/07/2023]
Abstract
BACKGROUND Crystallins are the important structural and functional proteins in the eye lens responsible for refractive index. Post-translational modifications (PTMs) and mutations are major causative factors that affect crystallin structural conformation and functional characteristics thus playing a vital role in the etiology of cataractogenesis. SCOPE OF REVIEW The significance of crystallin protein-protein interactions (PPIs) in the lens and non-lenticular tissues is summarized. MAJOR CONCLUSIONS Aberrancy of PPIs between crystallin, its associated protein and metal ions has been accomplished in various human diseases including cataract. A detailed account on multidimensional structural and functional significance of crystallin PPI in humans must be brought into limelight, in order to understand the biochemical and molecular basis augmenting the aberrancies of such interaction. In this scenario, the present review is focused to shed light on studies which will aid to expand our present understanding on disease pathogenesis related to loss of PPI thereby paving the way for putative future therapeutic targets to curb such diseases. GENERAL SIGNIFICANCE The interactions with α-crystallins always aid to protect their structural and functional characteristics. The up-regulation of αB-crystallin in the non-lenticular tissues always decodes as biomarker for various stress related disorders. For better understanding and treatment of various diseases, PPI studies provide overall outline about the structural and functional characteristics of the proteins. This information not only helps to find out the route of cataractogenesis but also aid to identify potential molecules to inhibit/prevent the further development of such complicated phenomenon. This article is part of a Special Issue entitled Crystallin Biochemistry in Health and Disease.
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Affiliation(s)
- Kumarasamy Anbarasu
- Department of Marine Biotechnology, Bharathidasan University, Tiruchirapalli 620024, Tamil Nadu, India.
| | - Jeyarajan Sivakumar
- Department of Marine Biotechnology, Bharathidasan University, Tiruchirapalli 620024, Tamil Nadu, India
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8
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Biswas A, Karmakar S, Chowdhury A, Das KP. Interaction of α-crystallin with some small molecules and its effect on its structure and function. Biochim Biophys Acta Gen Subj 2015; 1860:211-21. [PMID: 26073614 DOI: 10.1016/j.bbagen.2015.06.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 05/23/2015] [Accepted: 06/09/2015] [Indexed: 11/19/2022]
Abstract
BACKGROUND α-Crystallin acts like a molecular chaperone by interacting with its substrate proteins and thus prevents their aggregation. It also interacts with various kinds of small molecules that affect its structure and function. SCOPE OF REVIEW In this article we will present a review of work done with respect to the interaction of ATP, peptide generated from lens crystallin and other proteins and some bivalent metal ions with α-crystallin and discuss the role of these interactions on its structure and function and cataract formation. We will also discuss the interaction of some hydrophobic fluorescence probes and surface active agents with α-crystallin. MAJOR CONCLUSIONS Small molecule interaction controls the structure and function of α-crystallin. ATP and Zn+2 stabilize its structure and enhance chaperone function. Therefore the depletion of these small molecules can be detrimental to maintenance of lens transparency. However, the accumulation of small peptides due to protease activity in the lens can also be harmful as the interaction of these peptides with α-crystallin and other crystallin proteins in the lens promotes aggregation and loss of lens transparency. The use of hydrophobic probe has led to a wealth of information regarding the location of substrate binding site and nature of chaperone-substrate interaction. Interaction of surface active agents with α-crystallin has helped us to understand the structural stability and oligomeric dissociation in α-crystallin. GENERAL SIGNIFICANCE These interactions are very helpful in understanding the mechanistic details of the structural changes and chaperone function of α-crystallin. This article is part of a Special Issue entitled Crystallin Biochemistry in Health and Disease.
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Affiliation(s)
- A Biswas
- Protein Chemistry Laboratory, Department of Chemistry, Bose Institute, 93/1 A.P.C. Road, Kolkata 700 009, India.
| | - S Karmakar
- Protein Chemistry Laboratory, Department of Chemistry, Bose Institute, 93/1 A.P.C. Road, Kolkata 700 009, India.
| | - A Chowdhury
- Protein Chemistry Laboratory, Department of Chemistry, Bose Institute, 93/1 A.P.C. Road, Kolkata 700 009, India.
| | - K P Das
- Protein Chemistry Laboratory, Department of Chemistry, Bose Institute, 93/1 A.P.C. Road, Kolkata 700 009, India.
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Burmann BM, Hiller S. Chaperones and chaperone-substrate complexes: Dynamic playgrounds for NMR spectroscopists. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2015; 86-87:41-64. [PMID: 25919198 DOI: 10.1016/j.pnmrs.2015.02.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 02/19/2015] [Accepted: 02/19/2015] [Indexed: 05/20/2023]
Abstract
The majority of proteins depend on a well-defined three-dimensional structure to obtain their functionality. In the cellular environment, the process of protein folding is guided by molecular chaperones to avoid misfolding, aggregation, and the generation of toxic species. To this end, living cells contain complex networks of molecular chaperones, which interact with substrate polypeptides by a multitude of different functionalities: transport them towards a target location, help them fold, unfold misfolded species, resolve aggregates, or deliver them towards a proteolysis machinery. Despite the availability of high-resolution crystal structures of many important chaperones in their substrate-free apo forms, structural information about how substrates are bound by chaperones and how they are protected from misfolding and aggregation is very sparse. This lack of information arises from the highly dynamic nature of chaperone-substrate complexes, which so far has largely hindered their crystallization. This highly dynamic nature makes chaperone-substrate complexes good targets for NMR spectroscopy. Here, we review the results achieved by NMR spectroscopy to understand chaperone function in general and details of chaperone-substrate interactions in particular. We assess the information content and applicability of different NMR techniques for the characterization of chaperones and chaperone-substrate complexes. Finally, we highlight three recent studies, which have provided structural descriptions of chaperone-substrate complexes at atomic resolution.
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Affiliation(s)
- Björn M Burmann
- Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland
| | - Sebastian Hiller
- Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland.
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Interaction of amyloid inhibitor proteins with amyloid beta peptides: insight from molecular dynamics simulations. PLoS One 2014; 9:e113041. [PMID: 25422897 PMCID: PMC4244084 DOI: 10.1371/journal.pone.0113041] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 10/18/2014] [Indexed: 11/22/2022] Open
Abstract
Knowledge of the detailed mechanism by which proteins such as human αB- crystallin and human lysozyme inhibit amyloid beta (Aβ) peptide aggregation is crucial for designing treatment for Alzheimer's disease. Thus, unconstrained, atomistic molecular dynamics simulations in explicit solvent have been performed to characterize the Aβ17–42 assembly in presence of the αB-crystallin core domain and of lysozyme. Simulations reveal that both inhibitor proteins compete with inter-peptide interaction by binding to the peptides during the early stage of aggregation, which is consistent with their inhibitory action reported in experiments. However, the Aβ binding dynamics appear different for each inhibitor. The binding between crystallin and the peptide monomer, dominated by electrostatics, is relatively weak and transient due to the heterogeneous amino acid distribution of the inhibitor surface. The crystallin-bound Aβ oligomers are relatively long-lived, as they form more extensive contact surface with the inhibitor protein. In contrast, a high local density of arginines from lysozyme allows strong binding with Aβ peptide monomers, resulting in stable complexes. Our findings not only illustrate, in atomic detail, how the amyloid inhibitory mechanism of human αB-crystallin, a natural chaperone, is different from that of human lysozyme, but also may aid de novo design of amyloid inhibitors.
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11
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Alexander AG, Marfil V, Li C. Use of Caenorhabditis elegans as a model to study Alzheimer's disease and other neurodegenerative diseases. Front Genet 2014; 5:279. [PMID: 25250042 PMCID: PMC4155875 DOI: 10.3389/fgene.2014.00279] [Citation(s) in RCA: 189] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 07/31/2014] [Indexed: 12/12/2022] Open
Abstract
Advances in research and technology has increased our quality of life, allowed us to combat diseases, and achieve increased longevity. Unfortunately, increased longevity is accompanied by a rise in the incidences of age-related diseases such as Alzheimer’s disease (AD). AD is the sixth leading cause of death, and one of the leading causes of dementia amongst the aged population in the USA. It is a progressive neurodegenerative disorder, characterized by the prevalence of extracellular Aβ plaques and intracellular neurofibrillary tangles, derived from the proteolysis of the amyloid precursor protein (APP) and the hyperphosphorylation of microtubule-associated protein tau, respectively. Despite years of extensive research, the molecular mechanisms that underlie the pathology of AD remain unclear. Model organisms, such as the nematode, Caenorhabditis elegans, present a complementary approach to addressing these questions. C. elegans has many advantages as a model system to study AD and other neurodegenerative diseases. Like their mammalian counterparts, they have complex biochemical pathways, most of which are conserved. Genes in which mutations are correlated with AD have counterparts in C. elegans, including an APP-related gene, apl-1, a tau homolog, ptl-1, and presenilin homologs, such as sel-12 and hop-1. Since the neuronal connectivity in C. elegans has already been established, C. elegans is also advantageous in modeling learning and memory impairments seen during AD. This article addresses the insights C. elegans provide in studying AD and other neurodegenerative diseases. Additionally, we explore the advantages and drawbacks associated with using this model.
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Affiliation(s)
- Adanna G Alexander
- Department of Biology, City College of New York New York, NY, USA ; Department of Biology, The Graduate Center, City University of New York New York, NY, USA
| | - Vanessa Marfil
- Department of Biology, City College of New York New York, NY, USA
| | - Chris Li
- Department of Biology, City College of New York New York, NY, USA ; Department of Biology, The Graduate Center, City University of New York New York, NY, USA
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12
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Chang LYL, Lowe J, Ardiles A, Lim J, Grey AC, Robertson K, Danesh-Meyer H, Palacios AG, Acosta ML. Alzheimer's disease in the human eye. Clinical tests that identify ocular and visual information processing deficit as biomarkers. Alzheimers Dement 2013; 10:251-61. [PMID: 24011928 DOI: 10.1016/j.jalz.2013.06.004] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 05/21/2013] [Accepted: 06/03/2013] [Indexed: 12/19/2022]
Abstract
Alzheimer's disease (AD) is the most common form of dementia with progressive deterioration of memory and cognition. Complaints related to vision are common among AD patients. Several changes in the retina, lens, and in the vasculature have been noted in the AD eye that may be the cause of visual symptoms experienced by the AD patient. Anatomical changes have been detected within the eye before signs of cognitive impairment and memory loss are apparent. Unlike the brain, the eye is a unique organ that can be visualized noninvasively at the cellular level because of its transparent nature, which allows for inexpensive testing of biomarkers in a clinical setting. In this review, we have searched for candidate biomarkers that could enable diagnosis of AD, covering ocular neurodegeneration associated with functional tests. We explore the evidence that suggests that inexpensive, noninvasive clinical tests could be used to detect AD ocular biomarkers.
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Affiliation(s)
- Lily Y L Chang
- Department of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand; New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand
| | - Jennifer Lowe
- Department of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
| | - Alvaro Ardiles
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Julie Lim
- Department of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand; New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand
| | - Angus C Grey
- Department of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand; New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand
| | - Ken Robertson
- Department of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand; New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand
| | - Helen Danesh-Meyer
- New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand; Department of Ophthalmology, The University of Auckland, Auckland, New Zealand
| | - Adrian G Palacios
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Monica L Acosta
- Department of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand; New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand.
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13
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Effect of Hsp27 on early embryonic development in the mouse. Reprod Biomed Online 2013; 26:491-9. [DOI: 10.1016/j.rbmo.2013.01.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 01/06/2013] [Accepted: 01/08/2013] [Indexed: 11/18/2022]
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14
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Kannan R, Sreekumar PG, Hinton DR. Novel roles for α-crystallins in retinal function and disease. Prog Retin Eye Res 2012; 31:576-604. [PMID: 22721717 DOI: 10.1016/j.preteyeres.2012.06.001] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 05/31/2012] [Accepted: 06/04/2012] [Indexed: 01/18/2023]
Abstract
α-Crystallins are key members of the superfamily of small heat shock proteins that have been studied in detail in the ocular lens. Recently, novel functions for α-crystallins have been identified in the retina and in the retinal pigmented epithelium (RPE). αB-Crystallin has been localized to multiple compartments and organelles including mitochondria, golgi apparatus, endoplasmic reticulum and nucleus. α-Crystallins are regulated by oxidative and endoplasmic reticulum stress, and inhibit apoptosis-induced cell death. α-Crystallins interact with a large number of proteins that include other crystallins, and apoptotic, cytoskeletal, inflammatory, signaling, angiogenic, and growth factor molecules. Studies with RPE from αB-crystallin deficient mice have shown that αB-crystallin supports retinal and choroidal angiogenesis through its interaction with vascular endothelial growth factor. αB-Crystallin has also been shown to have novel functions in the extracellular space. In RPE, αB-crystallin is released from the apical surface in exosomes where it accumulates in the interphotoreceptor matrix and may function to protect neighboring cells. In other systems administration of exogenous recombinant αB-crystallin has been shown to be anti-inflammatory. Another newly described function of αB-crystallin is its ability to inhibit β-amyloid fibril formation. α-Crystallin minichaperone peptides have been identified that elicit anti-apoptotic function in addition to being efficient chaperones. Generation of liposomal particles and other modes of nanoencapsulation of these minipeptides could offer great therapeutic advantage in ocular delivery for a wide variety of retinal degenerative, inflammatory and vascular diseases including age-related macular degeneration and diabetic retinopathy.
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Affiliation(s)
- Ram Kannan
- Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Los Angeles, CA 90033, United States
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15
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Dehle FC, Ecroyd H, Musgrave IF, Carver JA. αB-Crystallin inhibits the cell toxicity associated with amyloid fibril formation by κ-casein and the amyloid-β peptide. Cell Stress Chaperones 2010; 15:1013-26. [PMID: 20632140 PMCID: PMC3024074 DOI: 10.1007/s12192-010-0212-z] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Revised: 06/24/2010] [Accepted: 06/25/2010] [Indexed: 10/19/2022] Open
Abstract
Amyloid fibril formation is associated with diseases such as Alzheimer's, Parkinson's, and prion diseases. Inhibition of amyloid fibril formation by molecular chaperone proteins, such as the small heat-shock protein αB-crystallin, may play a protective role in preventing the toxicity associated with this form of protein misfolding. Reduced and carboxymethylated κ-casein (RCMκ-CN), a protein derived from milk, readily and reproducibly forms fibrils at physiological temperature and pH. We investigated the toxicity of fibril formation by RCMκ-CN using neuronal model PC12 cells and determined whether the inhibition of fibril formation altered its cell toxicity. To resolve ambiguities in the literature, we also investigated whether fibril formation by amyloid-β1-40 (Aβ(1-40)), the peptide associated with Alzheimer's disease, was inhibited by αB-crystallin and if this affected the toxicity of Aβ. To this end, either RCMκ-CN or Aβ(1-40) was incubated at neutral pH to induce fibril formation before treating PC12 cells and assessing cell viability. Incubated (fibrillar) RCMκ-CN was more toxic to PC12 cells than native RCMκ-CN with the highest level of toxicity being associated with mature fibrils and protofibrils. Furthermore, the toxicity of RCMκ-CN was attenuated when its fibril formation was inhibited, either through the chaperone action of αB-crystallin or when it interacted with its natural binding partners in milk, α(S)- and β-casein. Likewise, incubating Aβ(1-40) with αB-crystallin inhibited both Aβ(1-40) fibril formation and the associated cell toxicity. Importantly, by inhibiting fibril formation, αB-crystallin prevents the cell toxicity associated with protein misfolding.
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Affiliation(s)
- Francis C. Dehle
- School of Chemistry & Physics, The University of Adelaide, Adelaide, SA 5005 Australia
| | - Heath Ecroyd
- School of Chemistry & Physics, The University of Adelaide, Adelaide, SA 5005 Australia
- School of Biological Sciences, University of Wollongong, Wollongong, NSW 2522 Australia
| | - Ian F. Musgrave
- Discipline of Pharmacology, School of Medical Sciences, The University of Adelaide, Adelaide, SA 5005 Australia
| | - John A. Carver
- School of Chemistry & Physics, The University of Adelaide, Adelaide, SA 5005 Australia
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16
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Andrieu C, Taieb D, Baylot V, Ettinger S, Soubeyran P, De-Thonel A, Nelson C, Garrido C, So A, Fazli L, Bladou F, Gleave M, Iovanna JL, Rocchi P. Heat shock protein 27 confers resistance to androgen ablation and chemotherapy in prostate cancer cells through eIF4E. Oncogene 2010; 29:1883-96. [DOI: 10.1038/onc.2009.479] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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17
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Transactivation response DNA-binding protein 43 microvasculopathy in frontotemporal degeneration and familial Lewy body disease. J Neuropathol Exp Neurol 2009; 68:1167-76. [PMID: 19816201 DOI: 10.1097/nen.0b013e3181baacec] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
We describe novel transactivation response DNA-binding protein of 43 kd (TDP-43)-positive structures in the brains of patients with frontotemporal lobar degeneration with ubiquitin-positive inclusions and familial Lewy body disease. The TDP-43 immunohistochemistry revealed small round structures closely associated with small blood vessels. By immunoelectron microscopy, these TDP-43-positive structures were unmyelinated cell processes located adjacent to and sometimes enclosed by the capillary basal lamina. Some processes protruded from outside of the vascular basal lamina to a position beneath the basal lamina. The processes contained 10- to 17-nm-diameter straight filaments or filaments coated with granular material similar to those described in neurites in frontotemporal lobar degeneration with ubiquitin-positive inclusions and other disorders. In some of the abnormal structures, electron-dense material formed paracrystalline arrays composed of TDP-43. The inclusions were variably positive by immunostaining for the small heat shock protein alphaB-crystallin and less often glial fibrillary acidic protein. Bundles of astrocytic glial fibrils characteristic of reactive astrocytes were often found in proximity, but glial fibrils were negative for TDP-43. These data suggest that these processes are astrocytic end-feet with abnormal TDP-43 fibrillary inclusions. The significance of this novel TDP-43 microvasculopathy on blood-brain barrier integrity warrants further investigation.
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18
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Abstract
Environmental and genetic conditions can cause proteins to misfold or to accumulate abnormally due to impaired clearance. The chaperones which include heat shock proteins, aid survival by preventing protein mis-folding and the formation of cytotoxic protein aggregates. An increasing number of studies point to important roles for molecular chaperones in the biology of neurodegenerative diseases. Heat shock proteins can suppress neurotoxicity in animal models of Parkinson's and polyglutamine diseases, suggesting potential new therapeutic approaches in neurodegenerative disorders associated with abnormal protein folding and toxicity. Recent findings suggest that heat shock proteins can also be neuroprotective in Alzheimer's disease, but this area of research remains largely unexplored. This paper will review the literature related to the role of heat shock proteins in Alzheimer's disease.
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Affiliation(s)
- R C Smith
- New England OncoTherapeutics Inc., Cambridge, MA 02142, USA.
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19
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In vitroperturbation of aggregation processes in β-amyloid peptides: A spectroscopic study. FEBS Lett 2008; 582:3288-92. [DOI: 10.1016/j.febslet.2008.08.039] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2008] [Revised: 08/18/2008] [Accepted: 08/29/2008] [Indexed: 11/20/2022]
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20
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Surolia I, Sinha S, Sarkar DP, Reddy PY, Reddy GB, Surolia A. Concurrence of Danish dementia and cataract: insights from the interactions of dementia associated peptides with eye lens alpha-crystallin. PLoS One 2008; 3:e2927. [PMID: 18698348 PMCID: PMC2488398 DOI: 10.1371/journal.pone.0002927] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Accepted: 07/14/2008] [Indexed: 11/19/2022] Open
Abstract
Familial Danish Dementia (FDD) is an autosomal disease, which is distinguished by gradual loss of vision, deafness, progressive ataxia and dementia. Cataract is the first manifestation of the disease. In this article, we demonstrate a specific correlation between the poisoning of the chaperone activity of the rat eye lens alpha-crystallins, loss of lens transparency in organ culture by the pathogenic form of the Danish dementia peptide, i.e. the reduced Danish dementia peptide (redADan peptide), by a combination of ex vivo, in vitro, biophysical and biochemical techniques. The interaction of redADan peptide and lens crystallins are very specific when compared with another chaperone, HSP-70, underscoring the specificity of the pathogenic form of Danish dementia peptide, redADan, for the early onset of cataract in this disease.
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Affiliation(s)
- Ira Surolia
- Department of Biochemistry, South Campus, Delhi University, New Delhi, India.
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21
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Wilhelmus MMM, de Waal RMW, Verbeek MM. Heat shock proteins and amateur chaperones in amyloid-Beta accumulation and clearance in Alzheimer's disease. Mol Neurobiol 2008; 35:203-16. [PMID: 17917109 PMCID: PMC2039847 DOI: 10.1007/s12035-007-0029-7] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Revised: 11/30/1999] [Accepted: 11/10/2006] [Indexed: 01/17/2023]
Abstract
The pathologic lesions of Alzheimer’s disease (AD) are characterized by accumulation of protein aggregates consisting of intracellular or extracellular misfolded proteins. The amyloid-β (Aβ) protein accumulates extracellularly in senile plaques and cerebral amyloid angiopathy, whereas the hyperphosphorylated tau protein accumulates intracellularly as neurofibrillary tangles. “Professional chaperones”, such as the heat shock protein family, have a function in the prevention of protein misfolding and subsequent aggregation. “Amateur” chaperones, such as apolipoproteins and heparan sulfate proteoglycans, bind amyloidogenic proteins and may affect their aggregation process. Professional and amateur chaperones not only colocalize with the pathological lesions of AD, but may also be involved in conformational changes of Aβ, and in the clearance of Aβ from the brain via phagocytosis or active transport across the blood–brain barrier. Thus, both professional and amateur chaperones may be involved in the aggregation, accumulation, persistence, and clearance of Aβ and tau and in other Aβ-associated reactions such as inflammation associated with AD lesions, and may, therefore, serve as potential targets for therapeutic intervention.
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Affiliation(s)
- Micha M M Wilhelmus
- Department of Neurology and Alzheimer Centre, Radboud University Nijmegen Medical Centre, 830 LKN, Nijmegen, 6500 HB, Netherlands
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22
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Interactive sequences in the molecular chaperone, human alphaB crystallin modulate the fibrillation of amyloidogenic proteins. Int J Biochem Cell Biol 2007; 40:954-67. [PMID: 18162431 DOI: 10.1016/j.biocel.2007.10.035] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2007] [Revised: 10/18/2007] [Accepted: 10/26/2007] [Indexed: 02/06/2023]
Abstract
Multiple interactive domains are involved in the activity of the stress protein, alphaB crystallin that protects against the unfolding, aggregation, and toxicity of amyloidogenic proteins. Six peptides corresponding to the interactive sequences 41STSLSPFYLRPPSFLRAP58, 73DRFSVNLDVKHFS85, 101HGKHEERQDE110, 113FISREFHR120, 131LTITSSLSSDGV142, and 156ERTIPITRE164 in human alphaB crystallin were synthesized and evaluated in Thioflavin T fluorescence assays for their effects on the modulation of fibrillation of four disease-related amyloidogenic proteins: amyloid-beta, alpha-synuclein, transthyretin, and beta2-microglobulin. The 73DRFSVNLDVKHFS85 and 101HGKHEERQDE110 peptides in the conserved alpha crystallin core domain of alphaB crystallin were the most effective fibril inhibitors. 73DRFSVNLDVKHFS85 completely inhibited alpha-synuclein fibrillation and reduced the fibrillation of amyloid-beta, transthyretin, and beta2-microglobulin by >50%. 101HGKHEERQDE110 completely inhibited amyloid-beta fibrillation and reduced the fibrillation of alpha-synuclein, transthyretin, and beta2-microglobulin by >50%. The peptides FSVN, NLDV, HGKH, and HEER, which are synthetic fragments of 73DRFSVNLDVKHFS85 and 101HGKHEERQDE110, inhibited fibrillation of all four amyloidogenic proteins by >75%. In contrast, the peptides FISREFHR, ERTIPITRE, DRFS, KHFS, and EERQ were the strongest promoters of fibrillation. Molecular modeling of the interactions between transthyretin and beta2-microglobulin and the synthetic bioactive peptides determined that residues Phe-75, Ser-76, Val-77, Asn-78, Leu-79, and Asp-80 in 73DRFSVNLDVKHFS85 and residues His-101, Lys-103, His-104, Glu-105, and Arg-107 in 101HGKHEERQDE110 interact with exposed residues in the beta strands, F and D of transthyretin and beta2-microglobulin, respectively, to modulate fibrillation. This is the first characterization of specific bioactive peptides synthesized on the basis of interactive domains in the small heat shock protein, alphaB crystallin that protect against the fibrillation of amyloidogenic proteins.
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23
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Fonte V, Kipp DR, Yerg J, Merin D, Forrestal M, Wagner E, Roberts CM, Link CD. Suppression of in vivo beta-amyloid peptide toxicity by overexpression of the HSP-16.2 small chaperone protein. J Biol Chem 2007; 283:784-91. [PMID: 17993648 DOI: 10.1074/jbc.m703339200] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Expression of the human beta-amyloid peptide (Abeta) in a transgenic Caenorhabditis elegans Alzheimer disease model leads to the induction of HSP-16 proteins, a family of small heat shock-inducible proteins homologous to vertebrate alphaB crystallin. These proteins also co-localize and co-immunoprecipitate with Abeta in this model (Fonte, V., Kapulkin, V., Taft, A., Fluet, A., Friedman, D., and Link, C. D. (2002) Proc. Natl. Acad. Sci. U. S. A. 99, 9439-9444). To investigate the molecular basis and biological function of this interaction between HSP-16 and Abeta, we generated transgenic C. elegans animals with high level, constitutive expression of HSP-16.2. We find that constitutive expression of wild type, but not mutant, HSP-16.2 partially suppresses Abeta toxicity. Wild type Abeta-(1-42), but not Abeta single chain dimer, was observed to become sequestered in HSP-16.2-containing inclusions, indicating a conformation-dependent interaction between HSP-16.2 and Abeta in vivo. Constitutive expression of HSP-16.2 could reduce amyloid fibril formation, but it did not reduce the overall accumulation of Abeta peptide or alter the pattern of the predominant oligomeric species. Studies with recombinant HSP-16.2 demonstrated that HSP-16.2 can bind directly to Abeta in vitro, with a preferential affinity for oligomeric Abeta species. This interaction between Abeta and HSP-16.2 also influences the formation of Abeta oligomers in in vitro assays. These studies are consistent with a model in which small chaperone proteins reduce Abeta toxicity by interacting directly with the Abeta peptide and altering its oligomerization pathways, thereby reducing the formation of a minor toxic species.
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Affiliation(s)
- Virginia Fonte
- Institute for Behavioral Genetics, University of Colorado, Boulder, Colorado 80309, USA
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24
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Treweek TM, Ecroyd H, Williams DM, Meehan S, Carver JA, Walker MJ. Site-directed mutations in the C-terminal extension of human alphaB-crystallin affect chaperone function and block amyloid fibril formation. PLoS One 2007; 2:e1046. [PMID: 17940610 PMCID: PMC2002509 DOI: 10.1371/journal.pone.0001046] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2007] [Accepted: 09/21/2007] [Indexed: 12/22/2022] Open
Abstract
Background Alzheimer's, Parkinson's and Creutzfeldt-Jakob disease are associated with inappropriate protein deposition and ordered amyloid fibril assembly. Molecular chaperones, including αB-crystallin, play a role in the prevention of protein deposition. Methodology/Principal Findings A series of site-directed mutants of the human molecular chaperone, αB-crystallin, were constructed which focused on the flexible C-terminal extension of the protein. We investigated the structural role of this region as well as its role in the chaperone function of αB-crystallin under different types of protein aggregation, i.e. disordered amorphous aggregation and ordered amyloid fibril assembly. It was found that mutation of lysine and glutamic acid residues in the C-terminal extension of αB-crystallin resulted in proteins that had improved chaperone activity against amyloid fibril forming target proteins compared to the wild-type protein. Conclusions/Significance Together, our results highlight the important role of the C-terminal region of αB-crystallin in regulating its secondary, tertiary and quaternary structure and conferring thermostability to the protein. The capacity to genetically modify αB-crystallin for improved ability to block amyloid fibril formation provides a platform for the future use of such engineered molecules in treatment of diseases caused by amyloid fibril formation.
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Affiliation(s)
- Teresa M. Treweek
- Department of Chemistry, University of Wollongong, Wollongong, New South Wales, Australia
- Graduate School of Medicine, University of Wollongong, Wollongong, New South Wales, Australia
| | - Heath Ecroyd
- School of Chemistry and Physics, The University of Adelaide, Adelaide, South Australia, Australia
| | - Danielle M. Williams
- School of Chemistry and Physics, The University of Adelaide, Adelaide, South Australia, Australia
| | - Sarah Meehan
- The University Chemical Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - John A. Carver
- School of Chemistry and Physics, The University of Adelaide, Adelaide, South Australia, Australia
| | - Mark J. Walker
- School of Biological Sciences, University of Wollongong, Wollongong, New South Wales, Australia
- * To whom correspondence should be addressed. E-mail:
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25
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Characterization of Interactions Between Misfolding Proteins and Molecular Chaperones by NMR Spectroscopy. Top Curr Chem (Cham) 2006. [DOI: 10.1007/128_066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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26
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Narayanan S, Kamps B, Boelens WC, Reif B. αB-crystallin competes with Alzheimer's disease β-amyloid peptide for peptide-peptide interactions and induces oxidation of Abeta-Met35. FEBS Lett 2006; 580:5941-6. [PMID: 17046756 DOI: 10.1016/j.febslet.2006.09.063] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Revised: 08/17/2006] [Accepted: 09/22/2006] [Indexed: 01/28/2023]
Abstract
Alzheimer's disease (AD) is associated with plaque deposition in the brain of AD patients. The major component of the aggregate is a 39-42 long peptide termed beta-amyloid (Abeta). Except for Abeta, plaques contain several other components which co-precipitate together with Abeta. One such component is the small heat shock protein (sHSP) alphaB-crystallin. Instead of preventing the cell from the neurotoxicity of Abeta, alphaB-crystallin induces an increased neurotoxicity. We find - using solution state NMR spectroscopy - that alphaB-crystallin competes efficiently for Abeta monomer-monomer interactions. Interactions between Abeta and alphaB-crystallin involve the hydrophobic core residues 17-21 as well as residues 31-32 of Abeta, and thus the same chemical groups which are important for Abeta aggregation. In the presence of alphaB-crystallin, Met35 in Abeta becomes efficiently oxidized. In order to quantify the redox properties of the different complexes consisting of Abeta/alphaB-crystallin/copper, we suggest an NMR assay which allows to estimate the electrochemical properties indirectly by monitoring the rate of glutathion (GSH) auto-oxidation. The oxidation of the side chain Met35 in Abeta might account for the increased neurotoxicity and the inability of Abeta to form fibrillar structures, which has been observed previously in the presence of alphaB-crystallin [Stege, G.J. et al. (1999) The molecular chaperone alphaB-crystallin enhances amyloid-beta neurotoxicity. Biochem. Biophys. Res. Commun. 262, 152-156.].
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Affiliation(s)
- Saravanakumar Narayanan
- Leibniz-Institut für Molekulare Pharmakologie (FMP), Robert-Rössle-Strasse, 10, 13125 Berlin, Germany
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27
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Lee S, Carson K, Rice-Ficht A, Good T. Small heat shock proteins differentially affect Abeta aggregation and toxicity. Biochem Biophys Res Commun 2006; 347:527-33. [PMID: 16828710 DOI: 10.1016/j.bbrc.2006.06.128] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Accepted: 06/22/2006] [Indexed: 10/24/2022]
Abstract
beta-Amyloid (Abeta) is the primary protein component of senile plaques in Alzheimer's disease (AD) and has been implicated in neurotoxicity associated with the disease. Abeta aggregates readily in vitro and in vivo, and its toxicity has been linked to its aggregation state. Prevention of Abeta aggregation has been investigated as a means to prevent Abeta toxicity associated with AD. Recently we found that Hsp20 from Babesia bovis prevented both Abeta aggregation and toxicity [S. Lee, K. Carson, A. Rice-Ficht, T. Good, Hsp20, a novel alpha-crystallin, prevents Abeta fibril formation and toxicity, Protein Sci. 14 (2005) 593-601.]. In this work, we examined the mechanism of Hsp20 interaction with Abeta1-40 and compared its activity to that of other small heat shock proteins, carrot Hsp17.7 and human Hsp27. While all three small heat shock proteins were able to prevent Abeta aggregation, only Hsp20 was able to attenuate Abeta toxicity in cultured SH-SY5Y cells. Understanding the mechanism of the Hsp20-Abeta interaction may provide insights into the design of the next generation of Abeta aggregation and toxicity inhibitors.
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Affiliation(s)
- Sungmun Lee
- Department of Chemical Engineering, Texas A&M University, College Station, TX 77843-3122, USA
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28
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Wilhelmus MMM, Boelens WC, Otte-Höller I, Kamps B, de Waal RMW, Verbeek MM. Small heat shock proteins inhibit amyloid-beta protein aggregation and cerebrovascular amyloid-beta protein toxicity. Brain Res 2006; 1089:67-78. [PMID: 16635482 DOI: 10.1016/j.brainres.2006.03.058] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2005] [Revised: 03/09/2006] [Accepted: 03/14/2006] [Indexed: 01/30/2023]
Abstract
Small heat shock proteins Hsp20 and HspB2/B3 co-localize with Abeta deposition in senile plaques and cerebral amyloid angiopathy in Alzheimer's disease brains, respectively. It was the aim of our study to investigate if these and other sHsps bind to wild-type Abeta1-42 or the more toxic Abeta1-40 carrying the 'Dutch' mutation (22Glu-->Gln) (D-Abeta1-40), affect Abeta aggregation and thereby influence Abeta cytotoxicity. Binding affinity between sHsps and Abeta was investigated by surface plasmon resonance. Abeta aggregation was studied by using circular dichroism spectroscopy and electron microscopy. Furthermore, we used cultured cerebrovascular cells to investigate the effects of sHsps on Abeta-mediated cytotoxicity. Hsp20, Hsp27 and alphaB-crystallin, but not HspB2/B3, bound to Abeta (both D-Abeta1-40 and Abeta1-42) and reduced or completely inhibited aggregation of D-Abeta1-40 into mature fibrils but did not affect Abeta1-42 aggregation. Furthermore, these sHsps were effective inhibitors of the cerebrovascular toxicity of Abeta (both D-Abeta1-40 and Abeta1-42) in vitro. Binding affinity of the sHsps to D-Abeta1-40 correlated to the degree of inhibition of Abeta-mediated cytotoxicity and the potential to reduce Abeta beta-sheet and fibril formation. With Abeta1-42, a similar correlation between binding affinity and cytotoxicity was observed, but not with its aggregation state. In conclusion, sHsps may regulate Abeta aggregation and serve as antagonists of the biological action of Abeta, but the extent of their interaction depends on the type of sHsp and Abeta peptide.
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Affiliation(s)
- Micha M M Wilhelmus
- Department of Neurology and Alzheimer Centre, 830 LKN, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
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29
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Wilhelmus MMM, Otte-Höller I, Wesseling P, de Waal RMW, Boelens WC, Verbeek MM. Specific association of small heat shock proteins with the pathological hallmarks of Alzheimer's disease brains. Neuropathol Appl Neurobiol 2006; 32:119-30. [PMID: 16599941 DOI: 10.1111/j.1365-2990.2006.00689.x] [Citation(s) in RCA: 168] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The small heat shock protein family (sHsp) comprises molecular chaperones able to interact with incorrectly folded proteins. Alzheimer's disease (AD) is characterized by pathological lesions such as senile plaques (SPs), cerebral amyloid angiopathy (CAA) and neurofibrillary tangles (NFTs), predominantly consisting of the incorrectly folded proteins amyloid-beta (Abeta) and tau respectively. The aim of this study was to investigate the association of the chaperones Hsp20, HspB2, alphaB-crystallin and Hsp27 with the pathological lesions of AD brains. For this purpose, a panel of well-characterized antibodies directed against these sHsps was used in immunohistochemistry and immunoblotting. We observed extracellular expression of Hsp20, Hsp27 and HspB2 in classic SPs, and Hsp20 expression in diffuse SPs. In addition, extracellular expression of HspB2 was observed in CAA. Both Hsp27 and alphaB-crystallin were also observed in astrocytes associated with both SPs and CAA. Furthermore, none of the sHsps were observed in NFTs in AD brains. We conclude that specific sHsp species may be involved in the pathogenesis of either SPs or CAA in AD.
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Affiliation(s)
- M M M Wilhelmus
- Department of Pathology, Radbound University Nijmegen Medical Centre, Nijmegen, the Netherlands.
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30
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Raman B, Ban T, Sakai M, Pasta S, Ramakrishna T, Naiki H, Goto Y, Rao C. AlphaB-crystallin, a small heat-shock protein, prevents the amyloid fibril growth of an amyloid beta-peptide and beta2-microglobulin. Biochem J 2006; 392:573-81. [PMID: 16053447 PMCID: PMC1316297 DOI: 10.1042/bj20050339] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
AlphaB-crystallin, a small heat-shock protein, exhibits molecular chaperone activity. We have studied the effect of alphaB-crystallin on the fibril growth of the Abeta (amyloid beta)-peptides Abeta-(1-40) and Abeta-(1-42). alphaB-crystallin, but not BSA or hen egg-white lysozyme, prevented the fibril growth of Abeta-(1-40), as revealed by thioflavin T binding, total internal reflection fluorescence microscopy and CD spectroscopy. Comparison of the activity of some mutants and chimaeric alpha-crystallins in preventing Abeta-(1-40) fibril growth with their previously reported chaperone ability in preventing dithiothreitol-induced aggregation of insulin suggests that there might be both common and distinct sites of interaction on alpha-crystallin involved in the prevention of amorphous aggregation of insulin and fibril growth of Abeta-(1-40). alphaB-crystallin also prevents the spontaneous fibril formation (without externally added seeds) of Abeta-(1-42), as well as the fibril growth of Abeta-(1-40) when seeded with the Abeta-(1-42) fibril seed. Sedimentation velocity measurements show that alphaB-crystallin does not form a stable complex with Abeta-(1-40). The mechanism by which it prevents the fibril growth differs from the known mechanism by which it prevents the amorphous aggregation of proteins. alphaB-crystallin binds to the amyloid fibrils of Abeta-(1-40), indicating that the preferential interaction of the chaperone with the fibril nucleus, which inhibits nucleation-dependent polymerization of amyloid fibrils, is the mechanism that is predominantly involved. We found that alphaB-crystallin prevents the fibril growth of beta2-microglobulin under acidic conditions. It also retards the depolymerization of beta2-microglobulin fibrils, indicating that it can interact with the fibrils. Our study sheds light on the role of small heat-shock proteins in protein conformational diseases, particularly in Alzheimer's disease.
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Affiliation(s)
- Bakthisaran Raman
- *Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
- †Institute for Protein Research, Osaka University, and CREST, Japan Science and Technology Agency, Yamadaoka 3-2, Suita, Osaka 565–0871, Japan
| | - Tadato Ban
- †Institute for Protein Research, Osaka University, and CREST, Japan Science and Technology Agency, Yamadaoka 3-2, Suita, Osaka 565–0871, Japan
| | - Miyo Sakai
- †Institute for Protein Research, Osaka University, and CREST, Japan Science and Technology Agency, Yamadaoka 3-2, Suita, Osaka 565–0871, Japan
| | - Saloni Y. Pasta
- *Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | | | - Hironobu Naiki
- ‡Faculty of Medical Science, University of Fukui, and CREST, Japan Science and Technology Agency, Matsuoka, Fukui 910-1193, Japan
| | - Yuji Goto
- ‡Faculty of Medical Science, University of Fukui, and CREST, Japan Science and Technology Agency, Matsuoka, Fukui 910-1193, Japan
- Correspondence may be addressed to either author (email or )
| | - Ch. Mohan Rao
- *Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
- Correspondence may be addressed to either author (email or )
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Wilhelmus MMM, Boelens WC, Otte-Höller I, Kamps B, Kusters B, Maat-Schieman MLC, de Waal RMW, Verbeek MM. Small heat shock protein HspB8: its distribution in Alzheimer's disease brains and its inhibition of amyloid-beta protein aggregation and cerebrovascular amyloid-beta toxicity. Acta Neuropathol 2006; 111:139-49. [PMID: 16485107 DOI: 10.1007/s00401-005-0030-z] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2005] [Revised: 11/16/2005] [Accepted: 11/16/2005] [Indexed: 12/13/2022]
Abstract
Alzheimer's disease (AD) is characterized by pathological lesions, such as senile plaques (SPs) and cerebral amyloid angiopathy (CAA), both predominantly consisting of a proteolytic cleavage product of the amyloid-beta precursor protein (APP), the amyloid-beta peptide (Abeta). CAA is also the major pathological lesion in hereditary cerebral hemorrhage with amyloidosis of the Dutch type (HCHWA-D), caused by a mutation in the gene coding for the Abeta peptide. Several members of the small heat shock protein (sHsp) family, such as alphaB-crystallin, Hsp27, Hsp20 and HspB2, are associated with the pathological lesions of AD, and the direct interaction between sHsps and Abeta has been demonstrated in vitro. HspB8, also named Hsp22 of H11, is a recently discovered member of the sHsp family, which has chaperone activity and is observed in neuronal tissue. Furthermore, HspB8 affects protein aggregation, which has been shown by its ability to prevent formation of mutant huntingtin aggregates. The aim of this study was to investigate whether HspB8 is associated with the pathological lesions of AD and HCHWA-D and whether there are effects of HspB8 on Abeta aggregation and Abeta-mediated cytotoxicity. We observed the expression of HspB8 in classic SPs in AD brains. In addition, HspB8 was found in CAA in HCHWA-D brains, but not in AD brains. Direct interaction of HspB8 with Abeta(1-42), Abeta(1-40) and Abeta(1-40) with the Dutch mutation was demonstrated by surface plasmon resonance. Furthermore, co-incubation of HspB8 with D-Abeta(1-40) resulted in the complete inhibition of D-Abeta(1-40)-mediated death of cerebrovascular cells, likely mediated by a reduction in both the beta-sheet formation of D-Abeta(1-40) and its accumulation at the cell surface. In contrast, however, with Abeta(1-42), HspB8 neither affected beta-sheet formation nor Abeta-mediated cell death. We conclude that HspB8 might play an important role in regulating Abeta aggregation and, therefore, the development of classic SPs in AD and CAA in HCHWA-D.
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Affiliation(s)
- Micha M M Wilhelmus
- Department of Neurology and Alzheimer centre, 830 LKN, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500, Nijmegen, The Netherlands
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Liu L, Ghosh JG, Clark JI, Jiang S. Studies of alphaB crystallin subunit dynamics by surface plasmon resonance. Anal Biochem 2006; 350:186-95. [PMID: 16480679 DOI: 10.1016/j.ab.2005.12.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2005] [Revised: 12/05/2005] [Accepted: 12/08/2005] [Indexed: 11/23/2022]
Abstract
The molecular chaperone activity of alphaB crystallin, an important stress protein in humans, is regulated by physiological factors, including temperature, pH, Ca2+, and ATP. In this study, the role of these factors in regulating the subunit dynamics of human alphaB crystallin was investigated using surface plasmon resonance (SPR). SPR experiments indicate that at temperatures above 37 degrees C, where alphaB crystallin has been reported to have higher chaperone activity, the subunit dynamics of alphaB crystallin were increased with faster association and dissociation rates. SPR experiments also indicate that interactions between alphaB crystallin subunits were enhanced with much faster association and slower dissociation rates at pH values below 7.0, where alphaB crystallin has been reported to have lower chaperone activity. The results suggest that the dynamic and rapid subunit exchange rate may regulate the chaperone activity of alphaB crystallin. The effect of Ca2+ and ATP on the subunit dynamics of alphaB crystallin was minimal, suggesting that Ca2+ and ATP modulate the chaperone activity of alphaB crystallin without altering the subunit dynamics. Based on the SPR results and previously reported biochemical data for the chaperone activity of alphaB crystallin under different conditions of temperature and pH, a model for the relationship between the subunit dynamics and chaperone activity of alphaB crystallin is established. The model is consistent with previous biochemical data for the chaperone activity and subunit dynamics of small heat shock proteins (sHSPs) and establishes a working hypothesis for the relationship between complex assembly and chaperone activity for sHSPs.
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Affiliation(s)
- Lingyun Liu
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
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Cottrell BA, Galvan V, Banwait S, Gorostiza O, Lombardo CR, Williams T, Schilling B, Peel A, Gibson B, Koo EH, Link CD, Bredesen DE. A pilot proteomic study of amyloid precursor interactors in Alzheimer's disease. Ann Neurol 2005; 58:277-89. [PMID: 16049941 PMCID: PMC1847583 DOI: 10.1002/ana.20554] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Several approaches have been used in an effort to identify proteins that interact with beta-amyloid precursor protein (APP). However, few studies have addressed the identification of proteins associated with APP in brain tissue from patients with Alzheimer's disease. We report the results of a pilot proteomic study performed on complexes immunoprecipitated with APP in brain samples of patients with Alzheimer's disease and normal control subjects. The 21 proteins identified could be grouped into five functional classes: molecular chaperones, cytoskeletal and structural proteins, proteins involved in trafficking, adaptors, and enzymes. Among the proteins identified, six had been reported previously as direct, indirect, or genetically inferred APP interactors. The other 15 proteins immunoprecipitated with APP were novel potential partners. We confirmed the APP interaction by Western blotting and coimmunolocalization in brain tissues, for 5 of the 21 interactors. In agreement with previous studies, our results are compatible with an involvement of APP in axonal transport and vesicular trafficking, and with a potential association of APP with cellular protein folding/protein degradation systems.
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Abstract
Small heat shock proteins (sHSPs) function as molecular chaperones, preventing stress induced aggregation of partially denatured proteins and promoting their return to native conformations when favorable conditions pertain. Sequence similarity between sHSPs resides predominately in an internal stretch of residues termed the alpha-crystallin domain, a region usually flanked by two extensions. The poorly conserved N-terminal extension influences oligomer construction and chaperone activity, whereas the flexible C-terminal extension stabilizes quaternary structure and enhances protein/substrate complex solubility. sHSP polypeptides assemble into dynamic oligomers which undergo subunit exchange and they bind a wide range of cellular substrates. As molecular chaperones, the sHSPs protect protein structure and activity, thereby preventing disease, but they may contribute to cell malfunction when perturbed. For example, sHSPs prevent cataract in the mammalian lens and guard against ischemic and reperfusion injury due to heart attack and stroke. On the other hand, mutated sHSPs are implicated in diseases such as desmin-related myopathy and they have an uncertain relationship to neurological disorders including Parkinson's and Alzheimer's disease. This review explores the involvement of sHSPs in disease and their potential for therapeutic intervention.
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Affiliation(s)
- Yu Sun
- Department of Biology, Dalhousie University, Halifax, Canada
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Lee S, Carson K, Rice-Ficht A, Good T. Hsp20, a novel alpha-crystallin, prevents Abeta fibril formation and toxicity. Protein Sci 2005; 14:593-601. [PMID: 15722443 PMCID: PMC2279291 DOI: 10.1110/ps.041020705] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Beta-amyloid (Abeta) is a major protein component of senile plaques in Alzheimer's disease, and is neurotoxic when aggregated. The size of aggregated Abeta responsible for the observed neurotoxicity and the mechanism of aggregation are still under investigation; however, prevention of Abeta aggregation still holds promise as a means to reduce Abeta neurotoxicity. In research presented here, we show that Hsp20, a novel alpha-crystallin isolated from the bovine erythrocyte parasite Babesia bovis, was able to prevent aggregation of denatured alcohol dehydrogenase when the two proteins are present at near equimolar levels. We then examined the ability of Hsp20 produced as two different fusion proteins to prevent Abeta amyloid formation as indicated by Congo Red binding; we found that not only was Hsp20 able to dramatically reduce Congo Red binding, but it was able to do so at molar ratios of Hsp20 to Abeta of 1 to 1000. Electron microscopy confirmed that Hsp20 does prevent Abeta fibril formation. Hsp20 was also able to significantly reduce Abeta toxicity to both SH-SY5Y and PC12 neuronal cells at similar molar ratios. At high concentrations of Hsp20, the protein no longer displays its aggregation inhibition and toxicity attenuation properties. Size exclusion chromatography indicated that Hsp20 was active at low concentrations in which dimer was present. Loss of activity at high concentrations was associated with the presence of higher oligomers of Hsp20. This work could contribute to the development of a novel aggregation inhibitor for prevention of Abeta toxicity.
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Affiliation(s)
- Sungmun Lee
- Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843-3122, USA
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Boros S, Kamps B, Wunderink L, de Bruijn W, de Jong WW, Boelens WC. Transglutaminase catalyzes differential crosslinking of small heat shock proteins and amyloid-beta. FEBS Lett 2004; 576:57-62. [PMID: 15474010 DOI: 10.1016/j.febslet.2004.08.062] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2004] [Accepted: 08/17/2004] [Indexed: 10/26/2022]
Abstract
Crosslinking of proteins by tissue transglutaminase (tTG) is enhanced in amyloid (Abeta) deposits characteristic of Alzheimer's disease and sporadic inclusion body myositis. Small heat shock proteins (sHsps) also occur in amyloid deposits. We here report the substrate characteristics for tTG of six sHsps. Hsp27, Hsp20 and HspB8 are both lysine- and glutamine-donors, alphaB-crystallin only is a lysine-donor, HspB2 a glutamine-donor, and HspB3 no substrate at all. Close interaction of proteins stimulates crosslinking efficiency as crosslinking between different sHsps only takes place within the same heteromeric complex. We also observed that alphaB-crystallin, Hsp27 and Hsp20 associate with Abeta in vitro, and can be readily crosslinked by tTG.
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Affiliation(s)
- Sandor Boros
- Department of Biochemistry 161, Nijmegen Center for Molecular Life Sciences, University of Nijmegen, P.O. Box 9101, 6500HB Nijmegen, The Netherlands
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Putilina T, Skouri-Panet F, Prat K, Lubsen NH, Tardieu A. Subunit exchange demonstrates a differential chaperone activity of calf alpha-crystallin toward beta LOW- and individual gamma-crystallins. J Biol Chem 2003; 278:13747-56. [PMID: 12562766 DOI: 10.1074/jbc.m208157200] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The chaperone activity of native alpha-crystallins toward beta(LOW)- and various gamma-crystallins at the onset of their denaturation, 60 and 66 degrees C, respectively, was studied at high and low crystallin concentrations using small angle x-ray scattering (SAXS) and fluorescence energy transfer (FRET). The crystallins were from calf lenses except for one recombinant human gamma S. SAXS data demonstrated an irreversible doubling in molecular weight and a corresponding increase in size of alpha-crystallins at temperatures above 60 degrees C. Further increase is observed at 66 degrees C. More subtle conformational changes accompanied the increase in size as shown by changes in environments around tryptophan and cysteine residues. These alpha-crystallin temperature-induced modifications were found necessary to allow for the association with beta(LOW)- and gamma-crystallins to occur. FRET experiments using IAEDANS (iodoacetylaminoethylaminonaphthalene sulfonic acid)- and IAF (iodoacetamidofluorescein)-labeled subunits showed that the heat-modified alpha-crystallins retained their ability to exchange subunits and that, at 37 degrees C, the rate of exchange was increased depending upon the temperature of incubation, 60 or 66 degrees C. Association with beta(LOW)- (60 degrees C) or various gamma-crystallins (66 degrees C) resulted at 37 degrees C in decreased subunit exchange in proportion to bound ligands. Therefore, beta(LOW)- and gamma-crystallins were compared for their capacity to associate with alpha-crystallins and inhibit subunit exchange. Quite unexpectedly for a highly conserved protein family, differences were observed between the individual gamma-crystallin family members. The strongest effect was observed for gamma S, followed by h gamma Srec, gamma E, gamma A-F, gamma D, gamma B. Moreover, fluorescence properties of alpha-crystallins in the presence of bound beta(LOW)-and gamma-crystallins indicated that the formation of beta(LOW)/alpha- or gamma/alpha-crystallin complexes involved various binding sites. The changes in subunit exchange associated with the chaperone properties of alpha-crystallins toward the other lens crystallins demonstrate the dynamic character of the heat-activated alpha-crystallin structure.
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Affiliation(s)
- Tatiana Putilina
- Laboratoire de Minéralogie-Cristallographie, CNRS and P6-P7 Universities, Case 115, 4 Place Jussieu, F75252 Paris Cedex 05, France
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Goldstein LE, Muffat JA, Cherny RA, Moir RD, Ericsson MH, Huang X, Mavros C, Coccia JA, Faget KY, Fitch KA, Masters CL, Tanzi RE, Chylack LT, Bush AI. Cytosolic beta-amyloid deposition and supranuclear cataracts in lenses from people with Alzheimer's disease. Lancet 2003; 361:1258-65. [PMID: 12699953 DOI: 10.1016/s0140-6736(03)12981-9] [Citation(s) in RCA: 245] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Pathological hallmarks of Alzheimer's disease include cerebral beta-amyloid (Abeta) deposition, amyloid accumulation, and neuritic plaque formation. We aimed to investigate the hypothesis that molecular pathological findings associated with Alzheimer's disease overlap in the lens and brain. METHODS We obtained postmortem specimens of eyes and brain from nine individuals with Alzheimer's disease and eight controls without the disorder, and samples of primary aqueous humour from three people without the disorder who were undergoing cataract surgery. Dissected lenses were analysed by slit-lamp stereophotomicroscopy, western blot, tryptic-digest/mass spectrometry electrospray ionisation, and anti-Abeta surface-enhanced laser desorption ionisation (SELDI) mass spectrometry, immunohistochemistry, and immunogold electron microscopy. Aqueous humour was analysed by anti-Abeta SELDI mass spectrometry. We did binding and aggregation studies to investigate Abeta-lens protein interactions. FINDINGS We identified Abeta1-40 and Abeta1-42 in lenses from people with and without Alzheimer's disease at concentrations comparable with brain, and Abeta1-40 in primary aqueous humour at concentrations comparable with cerebrospinal fluid. Abeta accumulated in lenses from individuals with Alzheimer's disease as electron-dense deposits located exclusively in the cytoplasm of supranuclear/deep cortical lens fibre cells (n=4). We consistently saw equatorial supranuclear cataracts in lenses from people with Alzheimer's disease (n=9) but not in controls (n=8). These supranuclear cataracts colocalised with enhanced Abeta immunoreactivity and birefringent Congo Red staining. Synthetic Abeta bound alphaB-crystallin, an abundant cytosolic lens protein. Abeta promoted lens protein aggregation that showed protofibrils, birefringent Congo Red staining, and Abeta/alphaB-crystallin coimmunoreactivity. INTERPRETATION Abeta is present in the cytosol of lens fibre cells of people with Alzheimer's disease. Lens Abeta might promote regionally-specific lens protein aggregation, extracerebral amyloid formation, and supranuclear cataracts.
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Affiliation(s)
- Lee E Goldstein
- Laboratory for Oxidation Biology, Massachusetts General Hospital, Charlestown, MA 02129-4404, USA
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Fonte V, Kapulkin WJ, Kapulkin V, Taft A, Fluet A, Friedman D, Link CD. Interaction of intracellular beta amyloid peptide with chaperone proteins. Proc Natl Acad Sci U S A 2002; 99:9439-44. [PMID: 12089340 PMCID: PMC123159 DOI: 10.1073/pnas.152313999] [Citation(s) in RCA: 167] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2002] [Accepted: 05/24/2002] [Indexed: 12/11/2022] Open
Abstract
Expression of the human beta amyloid peptide (A beta) in transgenic Caenorhabditis elegans animals can lead to the formation of intracellular immunoreactive deposits as well as the formation of intracellular amyloid. We have used this model to identify proteins that interact with intracellular A beta in vivo. Mass spectrometry analysis of proteins that specifically coimmunoprecipitate with A beta has identified six likely chaperone proteins: two members of the HSP70 family, three alpha B-crystallin-related small heat shock proteins (HSP-16s), and a putative ortholog of a mammalian small glutamine-rich tetratricopeptide repeat-containing protein proposed to regulate HSP70 function. Quantitative reverse transcription-PCR analysis shows that the small heat shock proteins are also transcriptionally induced by A beta expression. Immunohistochemistry demonstrates that HSP-16 protein closely colocalizes with intracellular A beta in this model. Transgenic animals expressing a nonaggregating A beta variant, a single-chain A beta dimer, show an altered pattern of coimmunoprecipitating proteins and an altered cellular distribution of HSP-16. Double-stranded RNA inhibition of R05F9.10, the putative C. elegans ortholog of the human small glutamine-rich tetratricopeptide-repeat-containing protein (SGT), results in suppression of toxicity associated with A beta expression. These results suggest that chaperone function can play a role in modulating intracellular A beta metabolism and toxicity.
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Affiliation(s)
- Virginia Fonte
- Institute for Behavioral Genetics, University of Colorado, Boulder, CO 80309, USA
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Abstract
alpha A-Crystallin high-molecular-weight (HMW) aggregates were prepared by preheating at 80-90 degrees C and studied using spectroscopic measurements. Conformational differences were suggested based on data of increased bis-ANS (4,4(')-dianilino-1,1(')-binaphthalene-5,5(')-disulfonic acid) and ThT (thioflavin T) fluorescence as well as increased far-UV and decreased near-UV circular dichroism (CD). These results indicated that HMW aggregated alpha-crystallin was more hydrophobic than the native alpha-crystallin, possibly resulting from partial unfolding of alpha-crystallin. The two cysteines in alpha A-crystallin were mostly oxidized in HMW aggregates. The effects of HMW aggregation on the dynamic structure were studied with fluorescence resonance energy transfer; subunit exchange became slower. These results strongly suggest that HMW alpha A-crystallin aggregates result from exposure of buried beta-pleated sheets and increased hydrophobic interaction.
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Affiliation(s)
- Jack J-N Liang
- Department of Ophthalmology, Center for Ophthalmic Research, Brigham and Women's Hospital, Harvard Medical School, 221 Longwood Avenue, Boston, MA 02115, USA.
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