1
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Wilkinson M, Gallardo RU, Martinez RM, Guthertz N, So M, Aubrey LD, Radford SE, Ranson NA. Disease-relevant β 2-microglobulin variants share a common amyloid fold. Nat Commun 2023; 14:1190. [PMID: 36864041 PMCID: PMC9981686 DOI: 10.1038/s41467-023-36791-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Accepted: 02/16/2023] [Indexed: 03/04/2023] Open
Abstract
β2-microglobulin (β2m) and its truncated variant ΔΝ6 are co-deposited in amyloid fibrils in the joints, causing the disorder dialysis-related amyloidosis (DRA). Point mutations of β2m result in diseases with distinct pathologies. β2m-D76N causes a rare systemic amyloidosis with protein deposited in the viscera in the absence of renal failure, whilst β2m-V27M is associated with renal failure, with amyloid deposits forming predominantly in the tongue. Here we use cryoEM to determine the structures of fibrils formed from these variants under identical conditions in vitro. We show that each fibril sample is polymorphic, with diversity arising from a 'lego-like' assembly of a common amyloid building block. These results suggest a 'many sequences, one amyloid fold' paradigm in contrast with the recently reported 'one sequence, many amyloid folds' behaviour of intrinsically disordered proteins such as tau and Aβ.
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Affiliation(s)
- Martin Wilkinson
- Astbury Centre for Structural Molecular Biology, School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Rodrigo U Gallardo
- Astbury Centre for Structural Molecular Biology, School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
- Aelin Therapeutics, Bio-Incubator Leuven, Gaston Geenslaan 1, 3001, Leuven, Belgium
| | - Roberto Maya Martinez
- Astbury Centre for Structural Molecular Biology, School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
- Peak Proteins, Birchwood House, Larkwood Way, Macclesfield, Cheshire, SK10 2XR, UK
| | - Nicolas Guthertz
- Astbury Centre for Structural Molecular Biology, School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
- Bicycle Therapeutics, Blocks A & B, Portway Building, Grant Park, Abingdon, Cambridge, CB21 6GS, UK
| | - Masatomo So
- Astbury Centre for Structural Molecular Biology, School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
- Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8521, Japan
| | - Liam D Aubrey
- Astbury Centre for Structural Molecular Biology, School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
| | - Neil A Ranson
- Astbury Centre for Structural Molecular Biology, School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
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2
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Prokaeva T, Joshi T, Klimtchuk ES, Gibson VM, Spencer B, Siddiqi O, Nedelkov D, Hu Y, Berk JL, Cuddy SAM, Dasari S, Chiu A, Choate LA, McPhail ED, Cui H, Chen H, Burks EJ, Sanchorawala V, Connors LH. A novel substitution of proline (P32L) destabilises β2-microglobulin inducing hereditary systemic amyloidosis. Amyloid 2022; 29:255-262. [PMID: 35575118 DOI: 10.1080/13506129.2022.2072199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BACKGROUND β2-microglobulin amyloidosis was first described in the 1980s as a protein deposition disease associated with long-term haemodialysis. More recently, two inherited forms resulting from separate point mutations in the β2-microglobulin gene have been identified. In this report, we detail a novel β2M variant, P32L, caused by a unique dinucleotide mutation that is linked to systemic hereditary β2-microglobulin amyloidosis. METHODS Three family members from a Portuguese kinship featured cardiomyopathy, requiring organ transplantation in one case, along with soft tissue involvement; other involvements included gastrointestinal, neuropathic and sicca syndrome. In vitro studies with recombinant P32L, P32G, D76N and wild-type β2-microglobulin were undertaken to compare the biophysical properties of the proteins. RESULTS The P32L variant was caused by the unique heterozygous dinucleotide mutation c.154_155delinsTT. Amyloid disease featured lowered serum β2-microglobulin levels with near equal amounts of circulating P32L and wild-type proteins; amyloid deposits were composed exclusively of P32L variant protein. In vitro studies of P32L demonstrated thermodynamic and chemical instability and enhanced susceptibility to proteolysis with rapid formation of pre-fibrillar oligomeric structures by N- and C-terminally truncated species under physiological conditions. CONCLUSIONS This work provides both clinical and experimental evidence supporting the critical role of P32 residue replacement in β2M amyloid fibrillogenesis.
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Affiliation(s)
- Tatiana Prokaeva
- Amyloidosis Center, Boston University School of Medicine, Boston, MA, USA
| | - Tracy Joshi
- Amyloidosis Center, Boston University School of Medicine, Boston, MA, USA
| | - Elena S Klimtchuk
- Amyloidosis Center, Boston University School of Medicine, Boston, MA, USA
| | - Victoria M Gibson
- Amyloidosis Center, Boston University School of Medicine, Boston, MA, USA
| | - Brian Spencer
- Amyloidosis Center, Boston University School of Medicine, Boston, MA, USA
| | - Omar Siddiqi
- Amyloidosis Center, Boston University School of Medicine, Boston, MA, USA
| | | | | | - John L Berk
- Amyloidosis Center, Boston University School of Medicine, Boston, MA, USA
| | - Sarah A M Cuddy
- Amyloidosis Program, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Surendra Dasari
- Department of Health Sciences Research, Mayo Clinic, Rochester, MN, USA
| | - April Chiu
- Department of Laboratory of Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Lauren A Choate
- Department of Laboratory of Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Ellen D McPhail
- Department of Laboratory of Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Haili Cui
- Amyloidosis Center, Boston University School of Medicine, Boston, MA, USA.,Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Hui Chen
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Eric J Burks
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA, USA
| | | | - Lawreen H Connors
- Amyloidosis Center, Boston University School of Medicine, Boston, MA, USA.,Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA, USA
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3
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Maya-Martinez R, Xu Y, Guthertz N, Walko M, Karamanos TK, Sobott F, Breeze AL, Radford SE. Dimers of D76N-β 2-microglobulin display potent antiamyloid aggregation activity. J Biol Chem 2022; 298:102659. [PMID: 36328246 PMCID: PMC9712992 DOI: 10.1016/j.jbc.2022.102659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 10/20/2022] [Accepted: 10/28/2022] [Indexed: 11/05/2022] Open
Abstract
Self-association of WT β2-microglobulin (WT-β2m) into amyloid fibrils is associated with the disorder dialysis related amyloidosis. In the familial variant D76N-β2m, the single amino acid substitution enhances the aggregation propensity of the protein dramatically and gives rise to a disorder that is independent of renal dysfunction. Numerous biophysical and structural studies on WT- and D76N-β2m have been performed in order to better understand the structure and dynamics of the native proteins and their different potentials to aggregate into amyloid. However, the structural properties of transient D76N-β2m oligomers and their role(s) in assembly remained uncharted. Here, we have utilized NMR methods, combined with photo-induced crosslinking, to detect, trap, and structurally characterize transient dimers of D76N-β2m. We show that the crosslinked D76N-β2m dimers have different structures from those previously characterized for the on-pathway dimers of ΔN6-β2m and are unable to assemble into amyloid. Instead, the crosslinked D76N-β2m dimers are potent inhibitors of amyloid formation, preventing primary nucleation and elongation/secondary nucleation when added in substoichiometric amounts with D76N-β2m monomers. The results highlight the specificity of early protein-protein interactions in amyloid formation and show how mapping these interfaces can inform new strategies to inhibit amyloid assembly.
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Affiliation(s)
- Roberto Maya-Martinez
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Yong Xu
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Nicolas Guthertz
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Martin Walko
- Astbury Centre for Structural Molecular Biology, School of Chemistry, University of Leeds, Leeds, United Kingdom
| | - Theodoros K Karamanos
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Frank Sobott
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Alexander L Breeze
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom.
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4
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Faravelli G, Mondani V, Mangione PP, Raimondi S, Marchese L, Lavatelli F, Stoppini M, Corazza A, Canetti D, Verona G, Obici L, Taylor GW, Gillmore JD, Giorgetti S, Bellotti V. Amyloid Formation by Globular Proteins: The Need to Narrow the Gap Between in Vitro and in Vivo Mechanisms. Front Mol Biosci 2022; 9:830006. [PMID: 35237660 PMCID: PMC8883118 DOI: 10.3389/fmolb.2022.830006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 01/20/2022] [Indexed: 11/15/2022] Open
Abstract
The globular to fibrillar transition of proteins represents a key pathogenic event in the development of amyloid diseases. Although systemic amyloidoses share the common characteristic of amyloid deposition in the extracellular matrix, they are clinically heterogeneous as the affected organs may vary. The observation that precursors of amyloid fibrils derived from circulating globular plasma proteins led to huge efforts in trying to elucidate the structural events determining the protein metamorphosis from their globular to fibrillar state. Whereas the process of metamorphosis has inspired poets and writers from Ovid to Kafka, protein metamorphism is a more recent concept. It is an ideal metaphor in biochemistry for studying the protein folding paradigm and investigating determinants of folding dynamics. Although we have learned how to transform both normal and pathogenic globular proteins into fibrillar polymers in vitro, the events occurring in vivo, are far more complex and yet to be explained. A major gap still exists between in vivo and in vitro models of fibrillogenesis as the biological complexity of the disease in living organisms cannot be reproduced at the same extent in the test tube. Reviewing the major scientific attempts to monitor the amyloidogenic metamorphosis of globular proteins in systems of increasing complexity, from cell culture to human tissues, may help to bridge the gap between the experimental models and the actual pathological events in patients.
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Affiliation(s)
- Giulia Faravelli
- Unit of Biochemistry, Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Valentina Mondani
- Unit of Biochemistry, Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - P. Patrizia Mangione
- Unit of Biochemistry, Department of Molecular Medicine, University of Pavia, Pavia, Italy
- Wolfson Drug Discovery Unit, Division of Medicine, Centre for Amyloidosis and Acute Phase Proteins, University College London, London, United Kingdom
| | - Sara Raimondi
- Unit of Biochemistry, Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Loredana Marchese
- Unit of Biochemistry, Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Francesca Lavatelli
- Unit of Biochemistry, Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Monica Stoppini
- Unit of Biochemistry, Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Alessandra Corazza
- Department of Medicine (DAME), University of Udine, Udine, Italy
- Istituto Nazionale Biostrutture e Biosistemi, Rome, Italy
| | - Diana Canetti
- Wolfson Drug Discovery Unit, Division of Medicine, Centre for Amyloidosis and Acute Phase Proteins, University College London, London, United Kingdom
| | - Guglielmo Verona
- Wolfson Drug Discovery Unit, Division of Medicine, Centre for Amyloidosis and Acute Phase Proteins, University College London, London, United Kingdom
| | - Laura Obici
- Amyloidosis Research and Treatment Centre, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Graham W. Taylor
- Wolfson Drug Discovery Unit, Division of Medicine, Centre for Amyloidosis and Acute Phase Proteins, University College London, London, United Kingdom
| | - Julian D. Gillmore
- National Amyloidosis Centre, University College London and Royal Free Hospital, London, United Kingdom
| | - Sofia Giorgetti
- Unit of Biochemistry, Department of Molecular Medicine, University of Pavia, Pavia, Italy
- Istituto Nazionale Biostrutture e Biosistemi, Rome, Italy
| | - Vittorio Bellotti
- Unit of Biochemistry, Department of Molecular Medicine, University of Pavia, Pavia, Italy
- Wolfson Drug Discovery Unit, Division of Medicine, Centre for Amyloidosis and Acute Phase Proteins, University College London, London, United Kingdom
- Istituto Nazionale Biostrutture e Biosistemi, Rome, Italy
- Scientific Direction, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
- *Correspondence: Vittorio Bellotti, ,
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5
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Cawood EE, Guthertz N, Ebo JS, Karamanos TK, Radford SE, Wilson AJ. Modulation of Amyloidogenic Protein Self-Assembly Using Tethered Small Molecules. J Am Chem Soc 2020; 142:20845-20854. [PMID: 33253560 PMCID: PMC7729939 DOI: 10.1021/jacs.0c10629] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
![]()
Protein–protein
interactions (PPIs) are involved in many
of life’s essential biological functions yet are also an underlying
cause of several human diseases, including amyloidosis. The modulation
of PPIs presents opportunities to gain mechanistic insights into amyloid
assembly, particularly through the use of methods which can trap specific
intermediates for detailed study. Such information can also provide
a starting point for drug discovery. Here, we demonstrate that covalently
tethered small molecule fragments can be used to stabilize specific
oligomers during amyloid fibril formation, facilitating the structural
characterization of these assembly intermediates. We exemplify the
power of covalent tethering using the naturally occurring truncated
variant (ΔN6) of the human protein β2-microglobulin
(β2m), which assembles into amyloid fibrils associated
with dialysis-related amyloidosis. Using this approach, we have trapped
tetramers formed by ΔN6 under conditions which would normally
lead to fibril formation and found that the degree of tetramer stabilization
depends on the site of the covalent tether and the nature of the protein–fragment
interaction. The covalent protein–ligand linkage enabled structural
characterization of these trapped, off-pathway oligomers using X-ray
crystallography and NMR, providing insight into why tetramer stabilization
inhibits amyloid assembly. Our findings highlight the power of “post-translational
chemical modification” as a tool to study biological molecular
mechanisms.
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Affiliation(s)
- Emma E Cawood
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom.,School of Chemistry, University of Leeds, Leeds LS2 9JT, United Kingdom.,School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Nicolas Guthertz
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom.,School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Jessica S Ebo
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom.,School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Theodoros K Karamanos
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom.,School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom.,Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom.,School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Andrew J Wilson
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom.,School of Chemistry, University of Leeds, Leeds LS2 9JT, United Kingdom
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6
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Loureiro RJS, Faísca PFN. The Early Phase of β2-Microglobulin Aggregation: Perspectives From Molecular Simulations. Front Mol Biosci 2020; 7:578433. [PMID: 33134317 PMCID: PMC7550760 DOI: 10.3389/fmolb.2020.578433] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 09/08/2020] [Indexed: 11/24/2022] Open
Abstract
Protein β2-microglobulin is the causing agent of two amyloidosis, dialysis related amyloidosis (DRA), affecting the bones and cartilages of individuals with chronic renal failure undergoing long-term hemodialysis, and a systemic amyloidosis, found in one French family, which impairs visceral organs. The protein’s small size and its biomedical significance attracted the attention of theoretical scientists, and there are now several studies addressing its aggregation mechanism in the context of molecular simulations. Here, we review the early phase of β2-microglobulin aggregation, by focusing on the identification and structural characterization of monomers with the ability to trigger aggregation, and initial small oligomers (dimers, tetramers, hexamers etc.) formed in the so-called nucleation phase. We focus our analysis on results from molecular simulations and integrate our views with those coming from in vitro experiments to provide a broader perspective of this interesting field of research. We also outline directions for future computer simulation studies.
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Affiliation(s)
- Rui J S Loureiro
- Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, University of Lisboa, Lisbon, Portugal
| | - Patrícia F N Faísca
- Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, University of Lisboa, Lisbon, Portugal.,Department of Physics, Faculty of Sciences, University of Lisboa, Lisbon, Portugal
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7
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Karamanos TK, Jackson MP, Calabrese AN, Goodchild SC, Cawood EE, Thompson GS, Kalverda AP, Hewitt EW, Radford SE. Structural mapping of oligomeric intermediates in an amyloid assembly pathway. eLife 2019; 8:46574. [PMID: 31552823 PMCID: PMC6783270 DOI: 10.7554/elife.46574] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 09/24/2019] [Indexed: 01/02/2023] Open
Abstract
Transient oligomers are commonly formed in the early stages of amyloid assembly. Determining the structure(s) of these species and defining their role(s) in assembly is key to devising new routes to control disease. Here, using a combination of chemical kinetics, NMR spectroscopy and other biophysical methods, we identify and structurally characterize the oligomers required for amyloid assembly of the protein ΔN6, a truncation variant of human β2-microglobulin (β2m) found in amyloid deposits in the joints of patients with dialysis-related amyloidosis. The results reveal an assembly pathway which is initiated by the formation of head-to-head non-toxic dimers and hexamers en route to amyloid fibrils. Comparison with inhibitory dimers shows that precise subunit organization determines amyloid assembly, while dynamics in the C-terminal strand hint to the initiation of cross-β structure formation. The results provide a detailed structural view of early amyloid assembly involving structured species that are not cytotoxic.
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Affiliation(s)
- Theodoros K Karamanos
- The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom.,School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Matthew P Jackson
- The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom.,School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Antonio N Calabrese
- The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom.,School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Sophia C Goodchild
- The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom.,School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Emma E Cawood
- The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom.,School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Gary S Thompson
- The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom.,School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Arnout P Kalverda
- The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom.,School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Eric W Hewitt
- The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom.,School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Sheena E Radford
- The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom.,School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
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8
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Benseny-Cases N, Karamanos TK, Hoop CL, Baum J, Radford SE. Extracellular matrix components modulate different stages in β 2-microglobulin amyloid formation. J Biol Chem 2019; 294:9392-9401. [PMID: 30996004 PMCID: PMC6579475 DOI: 10.1074/jbc.ra119.008300] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 04/09/2019] [Indexed: 11/26/2022] Open
Abstract
Amyloid deposition of WT human β2-microglobulin (WT-hβ2m) in the joints of long-term hemodialysis patients is the hallmark of dialysis-related amyloidosis. In vitro, WT-hβ2m does not form amyloid fibrils at physiological pH and temperature unless co-solvents or other reagents are added. Therefore, understanding how fibril formation is initiated and maintained in the joint space is important for elucidating WT-hβ2m aggregation and dialysis-related amyloidosis onset. Here, we investigated the roles of collagen I and the commonly administered anticoagulant, low-molecular-weight (LMW) heparin, in the initiation and subsequent aggregation phases of WT-hβ2m in physiologically relevant conditions. Using thioflavin T fluorescence to study the kinetics of amyloid formation, we analyzed how these two agents affect specific stages of WT-hβ2m assembly. Our results revealed that LMW-heparin strongly promotes WT-hβ2m fibrillogenesis during all stages of aggregation. However, collagen I affected WT-hβ2m amyloid formation in contrasting ways: decreasing the lag time of fibril formation in the presence of LMW-heparin and slowing the rate at higher concentrations. We found that in self-seeded reactions, interaction of collagen I with WT-hβ2m amyloid fibrils attenuates surface-mediated growth of WT-hβ2m fibrils, demonstrating a key role of secondary nucleation in WT-hβ2m amyloid formation. Interestingly, collagen I fibrils did not suppress surface-mediated assembly of WT-hβ2m monomers when cross-seeded with fibrils formed from the N-terminally truncated variant ΔN6-hβ2m. Together, these results provide detailed insights into how collagen I and LMW-heparin impact different stages in the aggregation of WT-hβ2m into amyloid, which lead to dramatic effects on the time course of assembly.
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Affiliation(s)
- Núria Benseny-Cases
- From the Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom and
| | - Theodoros K Karamanos
- From the Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom and
| | - Cody L Hoop
- the Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854
| | - Jean Baum
- the Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854
| | - Sheena E Radford
- From the Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom and
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9
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Olzscha H. Posttranslational modifications and proteinopathies: how guardians of the proteome are defeated. Biol Chem 2019; 400:895-915. [DOI: 10.1515/hsz-2018-0458] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 04/13/2019] [Indexed: 01/15/2023]
Abstract
Abstract
Protein folding is one of the fundamental processes in life and therefore needs to be tightly regulated. Many cellular quality control systems are in place to ensure that proteostasis is optimally adjusted for a changing environment, facilitating protein folding, translocation and degradation. These systems include the molecular chaperones and the major protein degradation systems, namely the ubiquitin proteasome system and autophagy. However, the capacity of the quality control systems can be exhausted and protein misfolding and aggregation, including the formation of amyloids, can occur as a result of ageing, mutations or exogenous influences. There are many known diseases in which protein misfolding and aggregation can be the underlying cause of the pathological condition; these are referred to as proteinopathies. Over the last decade, it has become clear that posttranslational modifications can govern and modulate protein folding, and that aberrant posttranslational modifications can cause or contribute to proteinopathies. This review provides an overview of protein folding and misfolding and the role of the major protein quality control systems. It focusses on different posttranslational modifications and gives examples of how these posttranslational modifications can alter protein folding and cause or accompany proteinopathies.
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Affiliation(s)
- Heidi Olzscha
- Institut für Physiologische Chemie , Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg , Hollystr. 1 , D-06114 Halle/Saale , Germany
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10
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Cornwell O, Radford SE, Ashcroft AE, Ault JR. Comparing Hydrogen Deuterium Exchange and Fast Photochemical Oxidation of Proteins: a Structural Characterisation of Wild-Type and ΔN6 β 2-Microglobulin. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:2413-2426. [PMID: 30267362 PMCID: PMC6276068 DOI: 10.1007/s13361-018-2067-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 09/07/2018] [Accepted: 09/10/2018] [Indexed: 05/23/2023]
Abstract
Hydrogen deuterium exchange (HDX) coupled to mass spectrometry (MS) is a well-established technique employed in the field of structural MS to probe the solvent accessibility, dynamics and hydrogen bonding of backbone amides in proteins. By contrast, fast photochemical oxidation of proteins (FPOP) uses hydroxyl radicals, liberated from the photolysis of hydrogen peroxide, to covalently label solvent accessible amino acid side chains on the microsecond-millisecond timescale. Here, we use these two techniques to study the structural and dynamical differences between the protein β2-microglobulin (β2m) and its amyloidogenic truncation variant, ΔN6. We show that HDX and FPOP highlight structural/dynamical differences in regions of the proteins, localised to the region surrounding the N-terminal truncation. Further, we demonstrate that, with carefully optimised LC-MS conditions, FPOP data can probe solvent accessibility at the sub-amino acid level, and that these data can be interpreted meaningfully to gain more detailed understanding of the local environment and orientation of the side chains in protein structures. Graphical Abstract ᅟ.
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Affiliation(s)
- Owen Cornwell
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Alison E Ashcroft
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
| | - James R Ault
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
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11
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The structure of a β 2-microglobulin fibril suggests a molecular basis for its amyloid polymorphism. Nat Commun 2018; 9:4517. [PMID: 30375379 PMCID: PMC6207761 DOI: 10.1038/s41467-018-06761-6] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 09/20/2018] [Indexed: 11/08/2022] Open
Abstract
All amyloid fibrils contain a cross-β fold. How this structure differs in fibrils formed from proteins associated with different diseases remains unclear. Here, we combine cryo-EM and MAS-NMR to determine the structure of an amyloid fibril formed in vitro from β2-microglobulin (β2m), the culprit protein of dialysis-related amyloidosis. The fibril is composed of two identical protofilaments assembled from subunits that do not share β2m's native tertiary fold, but are formed from similar β-strands. The fibrils share motifs with other amyloid fibrils, but also contain unique features including π-stacking interactions perpendicular to the fibril axis and an intramolecular disulfide that stabilises the subunit fold. We also describe a structural model for a second fibril morphology and show that it is built from the same subunit fold. The results provide insights into the mechanisms of fibril formation and the commonalities and differences within the amyloid fold in different protein sequences.
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12
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Sulatskaya AI, Rodina NP, Polyakov DS, Sulatsky MI, Artamonova TO, Khodorkovskii MA, Shavlovsky MM, Kuznetsova IM, Turoverov KK. Structural Features of Amyloid Fibrils Formed from the Full-Length and Truncated Forms of Beta-2-Microglobulin Probed by Fluorescent Dye Thioflavin T. Int J Mol Sci 2018; 19:E2762. [PMID: 30223436 PMCID: PMC6164334 DOI: 10.3390/ijms19092762] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 09/04/2018] [Accepted: 09/13/2018] [Indexed: 12/17/2022] Open
Abstract
The persistence of high concentrations of beta-2-microglobulin (β2M) in the blood of patients with acute renal failure leads to the development of the dialysis-related amyloidosis. This disease manifests in the deposition of amyloid fibrils formed from the various forms of β2M in the tissues and biological fluids of patients. In this paper, the amyloid fibrils formed from the full-length β2M (β2m) and its variants that lack the 6 and 10 N-terminal amino acids of the protein polypeptide chain (ΔN6β2m and ΔN10β2m, respectively) were probed by using the fluorescent dye thioflavin T (ThT). For this aim, the tested solutions were prepared via the equilibrium microdialysis approach. Spectroscopic analysis of the obtained samples allowed us to detect one binding mode (type) of ThT interaction with all the studied variants of β2M amyloid fibrils with affinity ~10⁴ M-1. This interaction can be explained by the dye molecules incorporation into the grooves that were formed by the amino acids side chains of amyloid protofibrils along the long axis of the fibrils. The decrease in the affinity and stoichiometry of the dye interaction with β2M fibrils, as well as in the fluorescence quantum yield and lifetime of the bound dye upon the shortening of the protein amino acid sequence were shown. The observed differences in the ThT-β2M fibrils binding parameters and characteristics of the bound dye allowed to prove not only the difference of the ΔN10β2m fibrils from other β2M fibrils (that can be detected visually, for example, by transmission electron microscopy (TEM), but also the differences between β2m and ΔN6β2m fibrils (that can not be unequivocally confirmed by other approaches). These results prove an essential role of N-terminal amino acids of the protein in the formation of the β2M amyloid fibrils. Information about amyloidogenic protein sequences can be claimed in the development of ways to inhibit β2M fibrillogenesis for the treatment of dialysis-related amyloidosis.
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Affiliation(s)
- Anna I Sulatskaya
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology of the Russian Academy of Science, Tikhoretsky ave. 4, St. Petersburg 194064, Russia.
| | - Natalia P Rodina
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology of the Russian Academy of Science, Tikhoretsky ave. 4, St. Petersburg 194064, Russia.
| | - Dmitry S Polyakov
- Department of Molecular Genetics, Institute of Experimental Medicine, Pavlov str. 12, St. Petersburg 197376, Russia.
- Chair of Medical Genetics, North-Western State Medical University named after I.I. Mechnikov, Piskarevskij prospect 47, St. Petersburg 195067, Russia.
| | - Maksim I Sulatsky
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology of the Russian Academy of Science, Tikhoretsky ave. 4, St. Petersburg 194064, Russia.
| | - Tatyana O Artamonova
- Research Center of Nanobiotechnologies, Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya 29, St. Petersburg 195251, Russia.
| | - Mikhail A Khodorkovskii
- Research Center of Nanobiotechnologies, Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya 29, St. Petersburg 195251, Russia.
| | - Mikhail M Shavlovsky
- Department of Molecular Genetics, Institute of Experimental Medicine, Pavlov str. 12, St. Petersburg 197376, Russia.
- Chair of Medical Genetics, North-Western State Medical University named after I.I. Mechnikov, Piskarevskij prospect 47, St. Petersburg 195067, Russia.
| | - Irina M Kuznetsova
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology of the Russian Academy of Science, Tikhoretsky ave. 4, St. Petersburg 194064, Russia.
| | - Konstantin K Turoverov
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology of the Russian Academy of Science, Tikhoretsky ave. 4, St. Petersburg 194064, Russia.
- Institute of Physics, Nanotechnology and Telecommunications, Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya 29, St. Petersburg 195251, Russia.
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13
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Morgan GJ, Usher GA, Kelly JW. Incomplete Refolding of Antibody Light Chains to Non-Native, Protease-Sensitive Conformations Leads to Aggregation: A Mechanism of Amyloidogenesis in Patients? Biochemistry 2017; 56:6597-6614. [PMID: 29200282 DOI: 10.1021/acs.biochem.7b00579] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Genetic, biochemical, and pharmacologic evidence supports the hypothesis that conformationally altered or misfolded protein states enable aggregation and cytotoxicity in the systemic amyloid diseases. Reversible structural fluctuations of natively folded proteins are involved in the aggregation of many degenerative disease associated proteins. Herein, we use antibody light chains (LCs) that form amyloid fibrils in AL amyloidosis to consider an alternative hypothesis of amyloidogenesis: that transient unfolding and incomplete extracellular refolding of secreted proteins can lead to metastable, alternatively folded states that are more susceptible to aggregation or to endoproteolysis that can release aggregation-prone fragments. Refolding of full-length λ6a LC dimers comprising an interchain disulfide bond from heat- or chaotrope-denatured ensembles in buffers yields the native dimeric state as well as alternatively folded dimers and aggregates. LC variants lacking an interchain disulfide bond appear to refold fully reversibly to the native state. The conformation of a backbone peptidyl-proline amide in the LC constant domain, which is cis in the native state, may determine whether the LC refolds back to the native state. A proline to alanine (P147A) LC variant, which cannot form the native cis-amide conformation, forms amyloid fibrils from the alternatively folded ensemble, whereas all the full-length λ6a LCs we have studied to date do not form amyloid under analogous conditions. P147A LC variants are susceptible to endoproteolysis by thrombin, enabling amyloidogenesis of the fragments released. Thus, non-native LC structural ensembles containing a tyrosine 146-proline 147 trans-amide bond can initiate and propagate amyloid formation, either directly or after aberrant endoproteolysis.
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Affiliation(s)
- Gareth J Morgan
- Departments of Chemistry and Molecular Medicine, and ‡The Skaggs Institute for Chemical Biology, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Grace A Usher
- Departments of Chemistry and Molecular Medicine, and ‡The Skaggs Institute for Chemical Biology, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Jeffery W Kelly
- Departments of Chemistry and Molecular Medicine, and ‡The Skaggs Institute for Chemical Biology, The Scripps Research Institute , La Jolla, California 92037, United States
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14
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Fukasawa K, Higashimoto Y, Ando Y, Motomiya Y. Selection of DNA Aptamer That Blocks the Fibrillogenesis of a Proteolytic Amyloidogenic Fragment of β 2 m. Ther Apher Dial 2017; 22:61-66. [PMID: 28960840 DOI: 10.1111/1744-9987.12591] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/22/2017] [Accepted: 06/14/2017] [Indexed: 01/10/2023]
Abstract
Dialysis-related amyloidosis (DRA) is a severe complication of hemodialysis that results in progressive destruction of bones and joints. Elevated concentrations of the β2 -microglobulin (β2 m) level in the serum of subjects on hemodialysis promote the formation of amyloid fibrils in osteoarticular tissues. β2 m lacking the N-terminal six residues of the mature protein (ΔN6β2 m) constitutes 25-30% of β2 m in ex vivo DRA amyloid. Unlike full-length wild-type β2 m, ΔN6β2 m forms amyloid fibrils at neutral pH in vitro. However, the role of ΔN6β2 m in DRA is, at present, poorly understood. In the present study, we screened novel phosphorothioate-modified aptamers directed against ΔN6β2 m using combinatorial chemistry in vitro. We identified 11 ΔN6β2 m aptamers; among the identified aptamers, clone #2, #8, and #10 aptamers had higher binding affinity to ΔN6β2 m than the others. Biolayer interferometry analysis revealed that KD values of clone #2, #8, and #10 aptamers were 56, 23, and 44 nM, respectively. Furthermore, the clone #8 aptamer inhibited fibril formation in a dose-dependent manner, as assessed by Thioflavin T fluorescence assay. Fibrils formed from ΔN6β2 m bind to Congo red, displaying changes in the absorbance spectrum of the dye characteristic of binding to amyloid fibrils, which was completely blocked by treatment with clone #8 aptamer. These results suggest the potential of ΔN6β2 m aptamers as tools for elucidating co-assembly mechanisms in amyloid formation.
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Affiliation(s)
- Kanon Fukasawa
- Department of Chemistry, Kurume University School of Medicine, Kurume, Fukuoka, Japan
| | - Yuichiro Higashimoto
- Department of Chemistry, Kurume University School of Medicine, Kurume, Fukuoka, Japan
| | - Yukio Ando
- Department of Neurology, Graduate School of Medical Sciences, Kumamoto University, Honjo, Kumamoto, Japan
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15
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Young LM, Tu LH, Raleigh DP, Ashcroft AE, Radford SE. Understanding co-polymerization in amyloid formation by direct observation of mixed oligomers. Chem Sci 2017; 8:5030-5040. [PMID: 28970890 PMCID: PMC5613229 DOI: 10.1039/c7sc00620a] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 05/03/2017] [Indexed: 12/15/2022] Open
Abstract
Although amyloid assembly in vitro is commonly investigated using single protein sequences, fibril formation in vivo can be more heterogeneous, involving co-assembly of proteins of different length, sequence and/or post-translational modifications. Emerging evidence suggests that co-polymerization can alter the rate and/or mechanism of aggregation and can contribute to pathogenicity. Electrospray ionization-ion mobility spectrometry-mass spectrometry (ESI-IMS-MS) is uniquely suited to the study of these heterogeneous ensembles. Here, ESI-IMS-MS combined with analysis of fibrillation rates using thioflavin T (ThT) fluorescence, is used to track the course of aggregation of variants of islet-amyloid polypeptide (IAPP) in isolation and in pairwise mixtures. We identify a sub-population of extended monomers as the key precursors of amyloid assembly, and reveal that the fastest aggregating sequence in peptide mixtures determines the lag time of fibrillation, despite being unable to cross-seed polymerization. The results demonstrate that co-polymerization of IAPP sequences radically alters the rate of amyloid assembly by altering the conformational properties of the mixed oligomers that form.
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Affiliation(s)
- Lydia M Young
- Astbury Centre for Structural Molecular Biology , School of Molecular and Cellular Biology , University of Leeds , Leeds LS2 9JT , UK .
| | - Ling-Hsien Tu
- Department of Chemistry , Stony Brook University , Stony Brook , New York 11794-3400 , USA
- Genomics Research Center , Academia Sinica , 128 Academia , Taipei 11529 , Taiwan
| | - Daniel P Raleigh
- Department of Chemistry , Stony Brook University , Stony Brook , New York 11794-3400 , USA
| | - Alison E Ashcroft
- Astbury Centre for Structural Molecular Biology , School of Molecular and Cellular Biology , University of Leeds , Leeds LS2 9JT , UK .
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology , School of Molecular and Cellular Biology , University of Leeds , Leeds LS2 9JT , UK .
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16
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Lucato CM, Lupton CJ, Halls ML, Ellisdon AM. Amyloidogenicity at a Distance: How Distal Protein Regions Modulate Aggregation in Disease. J Mol Biol 2017; 429:1289-1304. [PMID: 28342736 DOI: 10.1016/j.jmb.2017.03.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 03/12/2017] [Accepted: 03/14/2017] [Indexed: 12/14/2022]
Abstract
The misfolding of proteins to form amyloid is a key pathological feature of several progressive, and currently incurable, diseases. A mechanistic understanding of the pathway from soluble, native protein to insoluble amyloid is crucial for therapeutic design, and recent efforts have helped to elucidate the key molecular events that trigger protein misfolding. Generally, either global or local structural perturbations occur early in amyloidogenesis to expose aggregation-prone regions of the protein that can then self-associate to form toxic oligomers. Surprisingly, these initiating structural changes are often caused or influenced by protein regions distal to the classically amyloidogenic sequences. Understanding the importance of these distal regions in the pathogenic process has highlighted many remaining knowledge gaps regarding the precise molecular events that occur in classic aggregation pathways. In this review, we discuss how these distal regions can influence aggregation in disease and the recent technical and conceptual advances that have allowed this insight.
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Affiliation(s)
- Christina M Lucato
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia; Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | - Christopher J Lupton
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia; Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | - Michelle L Halls
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Andrew M Ellisdon
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia; Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia.
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17
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Scarff CA, Ashcroft AE, Radford SE. Characterization of Amyloid Oligomers by Electrospray Ionization-Ion Mobility Spectrometry-Mass Spectrometry (ESI-IMS-MS). Methods Mol Biol 2016; 1345:115-32. [PMID: 26453209 DOI: 10.1007/978-1-4939-2978-8_8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Soluble oligomers formed during the self-assembly of amyloidogenic peptide and protein species are generally thought to be highly toxic. Consequently, thorough characterization of these species is of much interest in the quest for effective therapeutics and for an enhanced understanding of amyloid fibrillation pathways. The structural characterization of oligomeric species, however, is challenging as they are often transiently and lowly populated, and highly heterogeneous. Electrospray ionization-ion mobility spectrometry-mass spectrometry (ESI-IMS-MS) is a powerful technique which is able to detect individual ion species populated within a complex heterogeneous mixture and characterize them in terms of shape, stoichiometry, ligand binding capability, and relative stability. Herein, we describe the use of ESI-IMS-MS to characterize the size and shape of oligomers of beta-2-microglobulin through use of data calibration and the derivation of models. This enables information about the range of oligomeric species populated en route to amyloid formation and the mode of oligomer growth to be obtained.
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Affiliation(s)
- Charlotte A Scarff
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Alison E Ashcroft
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK.
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Astbury Building, Room 10.122a, Leeds, LS2 9JT, UK.
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18
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Bertoletti L, Bisceglia F, Colombo R, Giorgetti S, Raimondi S, Mangione PP, De Lorenzi E. Capillary electrophoresis analysis of different variants of the amyloidogenic protein β2 -microglobulin as a simple tool for misfolding and stability studies. Electrophoresis 2015; 36:2465-72. [PMID: 26084573 DOI: 10.1002/elps.201500148] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 05/13/2015] [Accepted: 05/21/2015] [Indexed: 11/07/2022]
Abstract
Free solution capillary electrophoresis with UV detection is here used to retrieve information on the conformational changes of wild-type β2 -microglobulin and a series of naturally and artificially created variants known to have different stability and amyloidogenic potential. Under nondenaturing conditions, the resolution of at least two folding conformers at equilibrium is obtained and a third species is detected for the less stable isoforms. Partial denaturation by using chaotropic agents such as acetonitrile or trifluoroethanol reveals that the separated peaks are at equilibrium, as the presence of less structured species is either enhanced or induced at the expenses of the native form. Reproducible CE data allow to obtain an interesting semiquantitative correlation between the peak areas observed and the protein stability. Thermal unfolding over the range 25-42°C is induced inside the capillary for the two pathogenic proteins (wtβ2 -microglobulin and D76N variant): the large differences observed upon small temperature variation draw attention on the robustness of analytical methods when dealing with proteins prone to misfolding and aggregation.
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Affiliation(s)
| | | | | | - Sofia Giorgetti
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Sara Raimondi
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - P Patrizia Mangione
- Department of Molecular Medicine, University of Pavia, Pavia, Italy.,Centre for Amyloidosis and Acute Phase Proteins, University College London, London, UK
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19
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Pain C, Dumont J, Dumoulin M. Camelid single-domain antibody fragments: Uses and prospects to investigate protein misfolding and aggregation, and to treat diseases associated with these phenomena. Biochimie 2015; 111:82-106. [DOI: 10.1016/j.biochi.2015.01.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 01/23/2015] [Indexed: 12/19/2022]
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20
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Abstract
β2-Microglobulin is responsible for systemic amyloidosis affecting patients undergoing long-term hemodialysis. Its genetic variant D76N causes a very rare form of familial systemic amyloidosis. These two types of amyloidoses differ significantly in terms of the tissue localization of deposits and for major pathological features. Considering how the amyloidogenesis of the β2-microglobulin mechanism has been scrutinized in depth for the last three decades, the comparative analysis of molecular and pathological properties of wild type β2-microglobulin and of the D76N variant offers a unique opportunity to critically reconsider the current understanding of the relation between the protein's structural properties and its pathologic behavior.
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Affiliation(s)
- Monica Stoppini
- From the Department of Molecular Medicine, Institute of Biochemistry, University of Pavia, 27100 Pavia, Italy and
| | - Vittorio Bellotti
- From the Department of Molecular Medicine, Institute of Biochemistry, University of Pavia, 27100 Pavia, Italy and the Wolfson Drug Discovery Unit, Centre for Amyloidosis and Acute Phase Proteins, Division of Medicine, University College London, London NW3 2PF, United Kingdom
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21
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Sarell CJ, Karamanos TK, White SJ, Bunka DHJ, Kalverda AP, Thompson GS, Barker AM, Stockley PG, Radford SE. Distinguishing closely related amyloid precursors using an RNA aptamer. J Biol Chem 2014; 289:26859-26871. [PMID: 25100729 PMCID: PMC4175327 DOI: 10.1074/jbc.m114.595066] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although amyloid fibrils assembled in vitro commonly involve a single protein, fibrils formed in vivo can contain multiple protein sequences. The amyloidogenic protein human β2-microglobulin (hβ2m) can co-polymerize with its N-terminally truncated variant (ΔN6) in vitro to form hetero-polymeric fibrils that differ from their homo-polymeric counterparts. Discrimination between the different assembly precursors, for example by binding of a biomolecule to one species in a mixture of conformers, offers an opportunity to alter the course of co-assembly and the properties of the fibrils formed. Here, using hβ2m and its amyloidogenic counterpart, ΔΝ6, we describe selection of a 2'F-modified RNA aptamer able to distinguish between these very similar proteins. SELEX with a N30 RNA pool yielded an aptamer (B6) that binds hβ2m with an EC50 of ∼200 nM. NMR spectroscopy was used to assign the (1)H-(15)N HSQC spectrum of the B6-hβ2m complex, revealing that the aptamer binds to the face of hβ2m containing the A, B, E, and D β-strands. In contrast, binding of B6 to ΔN6 is weak and less specific. Kinetic analysis of the effect of B6 on co-polymerization of hβ2m and ΔN6 revealed that the aptamer alters the kinetics of co-polymerization of the two proteins. The results reveal the potential of RNA aptamers as tools for elucidating the mechanisms of co-assembly in amyloid formation and as reagents able to discriminate between very similar protein conformers with different amyloid propensity.
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Affiliation(s)
- Claire J Sarell
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Theodoros K Karamanos
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Simon J White
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - David H J Bunka
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Arnout P Kalverda
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Gary S Thompson
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Amy M Barker
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Peter G Stockley
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom.
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom.
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22
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Su Y, Sarell CJ, Eddy MT, Debelouchina GT, Andreas LB, Pashley CL, Radford SE, Griffin RG. Secondary structure in the core of amyloid fibrils formed from human β₂m and its truncated variant ΔN6. J Am Chem Soc 2014; 136:6313-25. [PMID: 24679070 PMCID: PMC4017606 DOI: 10.1021/ja4126092] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
![]()
Amyloid
fibrils formed from initially soluble proteins with diverse
sequences are associated with an array of human diseases. In the human
disorder, dialysis-related amyloidosis (DRA), fibrils contain two
major constituents, full-length human β2-microglobulin
(hβ2m) and a truncation variant, ΔN6 which
lacks the N-terminal six amino acids. These fibrils are assembled
from initially natively folded proteins with an all antiparallel β-stranded
structure. Here, backbone conformations of wild-type hβ2m and ΔN6 in their amyloid forms have been determined
using a combination of dilute isotopic labeling strategies and multidimensional
magic angle spinning (MAS) NMR techniques at high magnetic fields,
providing valuable structural information at the atomic-level about
the fibril architecture. The secondary structures of both fibril types,
determined by the assignment of ∼80% of the backbone resonances
of these 100- and 94-residue proteins, respectively, reveal substantial
backbone rearrangement compared with the location of β-strands
in their native immunoglobulin folds. The identification of seven
β-strands in hβ2m fibrils indicates that approximately
70 residues are in a β-strand conformation in the fibril core.
By contrast, nine β-strands comprise the fibrils formed from
ΔN6, indicating a more extensive core. The precise location
and length of β-strands in the two fibril forms also differ.
The results indicate fibrils of ΔN6 and hβ2m have an extensive core architecture involving the majority of residues
in the polypeptide sequence. The common elements of the backbone structure
of the two proteins likely facilitates their ability to copolymerize
during amyloid fibril assembly.
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Affiliation(s)
- Yongchao Su
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology Cambridge, Massachusetts 02139, United States
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23
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Sheynis T, Friediger A, Xue WF, Hellewell AL, Tipping KW, Hewitt EW, Radford SE, Jelinek R. Aggregation modulators interfere with membrane interactions of β2-microglobulin fibrils. Biophys J 2014; 105:745-55. [PMID: 23931322 DOI: 10.1016/j.bpj.2013.06.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 05/20/2013] [Accepted: 06/04/2013] [Indexed: 10/26/2022] Open
Abstract
Amyloid fibril accumulation is a pathological hallmark of several devastating disorders, including Alzheimer's disease, prion diseases, type II diabetes, and others. Although the molecular factors responsible for amyloid pathologies have not been deciphered, interactions of misfolded proteins with cell membranes appear to play important roles in these disorders. Despite increasing evidence for the involvement of membranes in amyloid-mediated cytotoxicity, the pursuit for therapeutic strategies has focused on preventing self-assembly of the proteins comprising the amyloid plaques. Here we present an investigation of the impact of fibrillation modulators upon membrane interactions of β2-microglobulin (β2m) fibrils. The experiments reveal that polyphenols (epigallocatechin gallate, bromophenol blue, and resveratrol) and glycosaminoglycans (heparin and heparin disaccharide) differentially affect membrane interactions of β2m fibrils measured by dye-release experiments, fluorescence anisotropy of labeled lipid, and confocal and cryo-electron microscopies. Interestingly, whereas epigallocatechin gallate and heparin prevent membrane damage as judged by these assays, the other compounds tested had little, or no, effect. The results suggest a new dimension to the biological impact of fibrillation modulators that involves interference with membrane interactions of amyloid species, adding to contemporary strategies for combating amyloid diseases that focus on disruption or remodeling of amyloid aggregates.
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Affiliation(s)
- Tania Sheynis
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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24
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Relini A, Marano N, Gliozzi A. Misfolding of amyloidogenic proteins and their interactions with membranes. Biomolecules 2013; 4:20-55. [PMID: 24970204 PMCID: PMC4030986 DOI: 10.3390/biom4010020] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 12/13/2013] [Accepted: 12/17/2013] [Indexed: 01/07/2023] Open
Abstract
In this paper, we discuss amyloidogenic proteins, their misfolding, resulting structures, and interactions with membranes, which lead to membrane damage and subsequent cell death. Many of these proteins are implicated in serious illnesses such as Alzheimer’s disease and Parkinson’s disease. Misfolding of amyloidogenic proteins leads to the formation of polymorphic oligomers and fibrils. Oligomeric aggregates are widely thought to be the toxic species, however, fibrils also play a role in membrane damage. We focus on the structure of these aggregates and their interactions with model membranes. Study of interactions of amlyoidogenic proteins with model and natural membranes has shown the importance of the lipid bilayer in protein misfolding and aggregation and has led to the development of several models for membrane permeabilization by the resulting amyloid aggregates. We discuss several of these models: formation of structured pores by misfolded amyloidogenic proteins, extraction of lipids, interactions with receptors in biological membranes, and membrane destabilization by amyloid aggregates perhaps analogous to that caused by antimicrobial peptides.
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Affiliation(s)
- Annalisa Relini
- Department of Physics, University of Genoa, Genoa 16146, Italy.
| | - Nadia Marano
- Department of Physics, University of Genoa, Genoa 16146, Italy.
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25
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Esposito G, Garvey M, Alverdi V, Pettirossi F, Corazza A, Fogolari F, Polano M, Mangione PP, Giorgetti S, Stoppini M, Rekas A, Bellotti V, Heck AJR, Carver JA. Monitoring the interaction between β2-microglobulin and the molecular chaperone αB-crystallin by NMR and mass spectrometry: αB-crystallin dissociates β2-microglobulin oligomers. J Biol Chem 2013; 288:17844-58. [PMID: 23645685 PMCID: PMC3682583 DOI: 10.1074/jbc.m112.448639] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2012] [Revised: 04/09/2013] [Indexed: 11/06/2022] Open
Abstract
The interaction at neutral pH between wild-type and a variant form (R3A) of the amyloid fibril-forming protein β2-microglobulin (β2m) and the molecular chaperone αB-crystallin was investigated by thioflavin T fluorescence, NMR spectroscopy, and mass spectrometry. Fibril formation of R3Aβ2m was potently prevented by αB-crystallin. αB-crystallin also prevented the unfolding and nonfibrillar aggregation of R3Aβ2m. From analysis of the NMR spectra collected at various R3Aβ2m to αB-crystallin molar subunit ratios, it is concluded that the structured β-sheet core and the apical loops of R3Aβ2m interact in a nonspecific manner with the αB-crystallin. Complementary information was derived from NMR diffusion coefficient measurements of wild-type β2m at a 100-fold concentration excess with respect to αB-crystallin. Mass spectrometry acquired in the native state showed that the onset of wild-type β2m oligomerization was effectively reduced by αB-crystallin. Furthermore, and most importantly, αB-crystallin reversibly dissociated β2m oligomers formed spontaneously in aged samples. These results, coupled with our previous studies, highlight the potent effectiveness of αB-crystallin in preventing β2m aggregation at the various stages of its aggregation pathway. Our findings are highly relevant to the emerging view that molecular chaperone action is intimately involved in the prevention of in vivo amyloid fibril formation.
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Affiliation(s)
- Gennaro Esposito
- From the Dipartimento di Scienze Mediche e Biologiche, Università di Udine, 33100 Udine, Italy
| | - Megan Garvey
- the School of Chemistry and Physics, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Vera Alverdi
- From the Dipartimento di Scienze Mediche e Biologiche, Università di Udine, 33100 Udine, Italy
| | - Fabio Pettirossi
- From the Dipartimento di Scienze Mediche e Biologiche, Università di Udine, 33100 Udine, Italy
| | - Alessandra Corazza
- From the Dipartimento di Scienze Mediche e Biologiche, Università di Udine, 33100 Udine, Italy
| | - Federico Fogolari
- From the Dipartimento di Scienze Mediche e Biologiche, Università di Udine, 33100 Udine, Italy
| | - Maurizio Polano
- From the Dipartimento di Scienze Mediche e Biologiche, Università di Udine, 33100 Udine, Italy
| | - P. Patrizia Mangione
- the Dipartimento di Medicina Molecolare, Istituto di Biochimica, Università di Pavia, 27100 Pavia, Italy
- the Wolfson Drug Discovery Unit, Centre for Amyloidosis and Acute Phase Proteins, Division of Medicine, University College London, London NW3 2PF, United Kingdom
| | - Sofia Giorgetti
- the Dipartimento di Medicina Molecolare, Istituto di Biochimica, Università di Pavia, 27100 Pavia, Italy
| | - Monica Stoppini
- the Dipartimento di Medicina Molecolare, Istituto di Biochimica, Università di Pavia, 27100 Pavia, Italy
| | - Agata Rekas
- the National Deuteration Facility, Australian Nuclear Science and Technology Organisation, Lucas Heights, New South Wales 2522, Australia, and
| | - Vittorio Bellotti
- the Dipartimento di Medicina Molecolare, Istituto di Biochimica, Università di Pavia, 27100 Pavia, Italy
- the Wolfson Drug Discovery Unit, Centre for Amyloidosis and Acute Phase Proteins, Division of Medicine, University College London, London NW3 2PF, United Kingdom
| | - Albert J. R. Heck
- the Department of Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, 3584 Utrecht, The Netherlands
| | - John A. Carver
- the School of Chemistry and Physics, University of Adelaide, Adelaide, South Australia 5005, Australia
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26
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Sarell CJ, Woods LA, Su Y, Debelouchina GT, Ashcroft AE, Griffin RG, Stockley PG, Radford SE. Expanding the repertoire of amyloid polymorphs by co-polymerization of related protein precursors. J Biol Chem 2013; 288:7327-37. [PMID: 23329840 PMCID: PMC3591641 DOI: 10.1074/jbc.m112.447524] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Amyloid fibrils can be generated from proteins with diverse sequences and folds. Although amyloid fibrils assembled in vitro commonly involve a single protein precursor, fibrils formed in vivo can contain more than one protein sequence. How fibril structure and stability differ in fibrils composed of single proteins (homopolymeric fibrils) from those generated by co-polymerization of more than one protein sequence (heteropolymeric fibrils) is poorly understood. Here we compare the structure and stability of homo and heteropolymeric fibrils formed from human β2-microglobulin and its truncated variant ΔN6. We use an array of approaches (limited proteolysis, magic angle spinning NMR, Fourier transform infrared spectroscopy, and fluorescence) combined with measurements of thermodynamic stability to characterize the different fibril types. The results reveal fibrils with different structural properties, different side-chain packing, and strikingly different stabilities. These findings demonstrate how co-polymerization of related precursor sequences can expand the repertoire of structural and thermodynamic polymorphism in amyloid fibrils to an extent that is greater than that obtained by polymerization of a single precursor alone.
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Affiliation(s)
- Claire J Sarell
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
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27
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Fukuda M, Takao T. Quantitative analysis of deamidation and isomerization in β2-microglobulin by 18O labeling. Anal Chem 2012; 84:10388-94. [PMID: 23126476 DOI: 10.1021/ac302603b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Deamidation of asparagine residues in proteins via the formation of a 5-membered succinimide ring intermediate is a nonenzymatic intramolecular reaction and, in general, occurs most rapidly at an Asn-Gly sequence. A protein containing this sequence would, therefore, be susceptible to modification, and the result would produce a structural alteration in the molecule. An Asn would be replaced with an Asp, resulting in an increase in the overall negative charge on the molecule but also an isomerization to isoAsp. Despite the fact that such a structural replacement could affect the functional properties of a protein, estimating the susceptibility of the Asn-Gly sequence to deamidation/isomerization remains a difficult task. This is especially true for proteins that are subjected to enzymatic digestion during their characterization, since the above transformation could occur spontaneously during this treatment. To address this issue, we applied a stable-isotope (18)O-labeling method combined with nano-LC-MS/MS to examine the susceptibility of two Asn-Gly sites in β2-microglobulin (β2m) to the reaction. The method permits the reaction occurring in a protein to be distinguished from that during enzymatic treatment. When β2m was incubated for 60 days at 37 °C, deamidation at Asn17-Gly and Asn42-Gly with half-lives of 33 and 347 days occurred, respectively. Moreover, a comparison of the deamidated products to synthetic peptides revealed that 44% of the Asp17 and 96% of the Asp42 had been converted into isoAsp forms. Interestingly, such structurally altered β2m showed a specific affinity for divalent Cu(2+) ions, which is thought to be a candidate for initiating fibril formation.
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Affiliation(s)
- Masafumi Fukuda
- Laboratory of Protein Profiling and Functional Proteomics, Institute for Protein Research, Osaka University, Yamadaoka, Japan
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28
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Abstract
Dialysis-related amyloidosis (DRA) is a clinical syndrome of pain, loss of function and other symptoms due to the deposition of amyloid consisting of β(2)-microglobulin (β(2)m) in the musculoskeletal system. The condition is seen in patients who suffer from chronic kidney disease and are treated with hemodialysis for a long time. Even though β(2)m easily can be manipulated to form amyloid in laboratory experiments under non-physiological conditions the precise mechanisms involved in the formation of β(2)m-amyloid in patients with DRA have been difficult to unravel. The current knowledge which is reviewed here indicates that conformational fluctuations centered around the D-strand, the DE-loop, and around the cis-configured Pro32 peptide bond are involved in β(2)m amyloidosis. Also required are highly increased concentrations of circulating β(2)m and possibly various post-translational modifications mediated by the pro-inflammatory environment in uremic blood, together with the influence of divalent metal ions (specifically Cu(2 +)), uremic toxins, and dialysis-enhanced redox-processes. It seems plausible that domain-swapped β(2)m dimers act as building blocks of β-spine cross-β -sheet fibrils consisting of otherwise globular, roughly natively folded protein. An activated complement system and cellular activation perpetuate these reactions which due to the affinity of β(2)m-amyloid for the collagen of synovial surfaces result in the DRA syndrome.
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Affiliation(s)
- Dorthe B Corlin
- Department of Clinical Biochemistry and Immunology, Division of Microbiology and Diagnostics, Statens Serum Institut, Bldg. 85/240, Artillerivej 5, 2300, Copenhagen S, Denmark,
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29
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Esposito G, Corazza A, Bellotti V. Pathological self-aggregation of β(2)-microglobulin: a challenge for protein biophysics. Subcell Biochem 2012; 65:165-183. [PMID: 23225003 DOI: 10.1007/978-94-007-5416-4_7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The pathological aggregation of b(2)-microglobulin (b2m) is examined starting from the relevance of some structural aspects of the protein. The systemic deposition of b2m fibrils has been ascribed to several factors, but no conclusive evidence emerged so far. The characterization of b2m aggregates by direct investigation through electron microscopy, atomic force microscopy, solid state NMR and other solid state techniques provides important structural and morphological information on the assembly, but no clues about the mechanism of the aggregation process. The most relevant mechanistic hypotheses are critically reviewed. In addition to the mechanisms exclusively based on structural features, also the recently reported prion-like conversion is analyzed and shown to hardly comply with some established conditions of the fibrillogenic process. An alternative mechanism is recalled that does not require rare events and involves only the full-length protein in proximity of collagen, i.e. the environment that physiologically supports deposition.
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Affiliation(s)
- Gennaro Esposito
- Dipartimento di Scienze Mediche e Biologiche, Università di Udine, P.le Kolbe, 4, 33100, Udine, Italy,
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30
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Porter MY, Routledge KE, Radford SE, Hewitt EW. Characterization of the response of primary cells relevant to dialysis-related amyloidosis to β2-microglobulin monomer and fibrils. PLoS One 2011; 6:e27353. [PMID: 22096558 PMCID: PMC3212568 DOI: 10.1371/journal.pone.0027353] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Accepted: 10/14/2011] [Indexed: 11/18/2022] Open
Abstract
The formation of insoluble amyloid fibrils is associated with an array of devastating human diseases. Dialysis-related amyloidosis (DRA) is a severe complication of hemodialysis that results in the progressive destruction of the bones and joints. Elevated concentrations of β2-microglobulin (β2m) in the serum of subjects on hemodialysis promote the formation of amyloid fibrils in the osteoarticular tissues, but the cellular basis for the destruction of these tissues in DRA is poorly understood. In this study we performed a systematic analysis of the interaction of monomeric and fibrillar β2m with primary human cells of the types present in the synovial joints of subjects with DRA. Building upon observations that macrophages infiltrate β2m amyloid deposits in vivo we demonstrate that monocytes, the precursors of macrophages, cannot degrade β2m fibrils, and that both monomeric β2m and fibrillar β2m are cytotoxic to these cells. β2m fibrils also impair the formation of bone resorbing osteoclasts from monocytes and reduce the viability of osteoblasts, the cell type that produces bone. As a consequence, we predict that β2m amyloid will disrupt the remodelling of the bone, which is critical for the maintenance of this tissue. Moreover, we show that β2m fibrils reduce the viability of chondrocytes, rationalizing the loss of cartilage in DRA. Together, our observations demonstrate that β2m cytotoxicity has multiple cellular targets in the osteoarticular tissues and is likely to be a key factor in the bone and joint destruction characteristic of DRA.
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Affiliation(s)
- Morwenna Y. Porter
- Astbury Centre for Structural Molecular Biology and Institute of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Katy E. Routledge
- Astbury Centre for Structural Molecular Biology and Institute of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Sheena E. Radford
- Astbury Centre for Structural Molecular Biology and Institute of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Eric W. Hewitt
- Astbury Centre for Structural Molecular Biology and Institute of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
- * E-mail:
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31
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Eichner T, Radford SE. Understanding the complex mechanisms of β2-microglobulin amyloid assembly. FEBS J 2011; 278:3868-83. [PMID: 21595827 PMCID: PMC3229708 DOI: 10.1111/j.1742-4658.2011.08186.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 05/11/2011] [Accepted: 05/13/2011] [Indexed: 11/30/2022]
Abstract
Several protein misfolding diseases are associated with the conversion of native proteins into ordered protein aggregates known as amyloid. Studies of amyloid assemblies have indicated that non-native proteins are responsible for initiating aggregation in vitro and in vivo. Despite the importance of these species for understanding amyloid disease, the structural and dynamic features of amyloidogenic intermediates and the molecular details of how they aggregate remain elusive. This review focuses on recent advances in developing a molecular description of the folding and aggregation mechanisms of the human amyloidogenic protein β(2)-microglobulin under physiologically relevant conditions. In particular, the structural and dynamic properties of the non-native folding intermediate I(T) and its role in the initiation of fibrillation and the development of dialysis-related amyloidosis are discussed.
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Affiliation(s)
- Timo Eichner
- Department of Biochemistry, Brandeis University, Waltham, MA 02454, USA.
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32
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Gierasch LM. How one bad protein spoils the barrel: structural details of β2-microglobulin amyloidogenicity. Mol Cell 2011; 41:129-31. [PMID: 21255721 DOI: 10.1016/j.molcel.2011.01.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In this issue, Eichner et al. (2011) describe at atomic resolution the structure of an amyloidogenic state of β(2)-microglobulin and how it may corrupt a soluble counterpart in the pathological scenario that ensues when good proteins go to the "dark side'" and form infectious toxic amyloid.
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Affiliation(s)
- Lila M Gierasch
- Department of Biochemistry & Molecular Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA.
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33
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Liu C, Sawaya MR, Eisenberg D. β₂-microglobulin forms three-dimensional domain-swapped amyloid fibrils with disulfide linkages. Nat Struct Mol Biol 2011; 18:49-55. [PMID: 21131979 PMCID: PMC3058263 DOI: 10.1038/nsmb.1948] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Accepted: 09/16/2010] [Indexed: 01/07/2023]
Abstract
β₂-microglobulin (β₂m) is the light chain of the type I major histocompatibility complex. It deposits as amyloid fibrils within joints during long-term hemodialysis treatment. Despite the devastating effects of dialysis-related amyloidosis, full understanding of how fibrils form from soluble β₂m remains elusive. Here we show that β₂m can oligomerize and fibrillize via three-dimensional domain swapping. Isolating a covalently bound, domain-swapped dimer from β₂m oligomers on the pathway to fibrils, we were able to determine its crystal structure. The hinge loop that connects the swapped domain to the core domain includes the fibrillizing segment LSFSKD, whose atomic structure we also determined. The LSFSKD structure reveals a class 5 steric zipper, akin to other amyloid spines. The structures of the dimer and the zipper spine fit well into an atomic model for this fibrillar form of β₂m, which assembles slowly under physiological conditions.
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Screening of fibrillogenesis inhibitors of β2-microglobulin: Integrated strategies by mass spectrometry capillary electrophoresis and in silico simulations. Anal Chim Acta 2011; 685:153-61. [DOI: 10.1016/j.aca.2010.11.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Revised: 11/10/2010] [Accepted: 11/11/2010] [Indexed: 11/18/2022]
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35
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Yoshimura Y, Sakurai K, Lee YH, Ikegami T, Chatani E, Naiki H, Goto Y. Direct observation of minimum-sized amyloid fibrils using solution NMR spectroscopy. Protein Sci 2010; 19:2347-55. [PMID: 20936689 DOI: 10.1002/pro.515] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 09/17/2010] [Accepted: 09/20/2010] [Indexed: 11/10/2022]
Abstract
It is challenging to investigate the structure and dynamics of amyloid fibrils at the residue and atomic resolution because of their high molecular weight and heterogeneous properties. Here, we used solution nuclear magnetic resonance (NMR) spectroscopy to characterize the conformation and flexibility of amyloid fibrils of β2-microglobulin (β2m), for which direct observation of solution NMR could not be made. Ultrasonication led to fragmentation producing a solution of minimum-sized fibrils with a molecular weight of around 6 MDa. In 1H-15N heteronuclear single-quantum correlation measurements, five signals, derived from N-terminal residues (i.e., Ile1, Gln2, Arg3, Thr4, and Lys6), were newly detected. Signal strength decreased with the distance from the N-terminal end. Capping experiments with the unlabeled β2m monomer indicated that the signals originated from molecules located inside the fibrils. Ultrasonication makes the residues with moderate flexibility observable by reducing size of the fibrils. Thus, solution NMR measurements of ultrasonicated fibrils will be promising for studying the structure and dynamics of fibrils.
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Affiliation(s)
- Yuichi Yoshimura
- Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan
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36
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Mustata M, Capone R, Jang H, Arce FT, Ramachandran S, Lal R, Nussinov R. K3 fragment of amyloidogenic beta(2)-microglobulin forms ion channels: implication for dialysis related amyloidosis. J Am Chem Soc 2010; 131:14938-45. [PMID: 19824733 DOI: 10.1021/ja9049299] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Beta(2)-microglobulin (beta(2)m) amyloid deposits are linked to dialysis-related amyloidosis (DRA) in hemodialysis patients. The mechanism by which beta(2)m causes DRA is not understood. It is also unclear whether only the full-length beta(2)m induces pathophysiology or if proteolytic fragments are sufficient for inducing this effect. Ser20-Lys41 (K3) is a digestion fragment of full-length beta(2)m. Solid state NMR (ssNMR) combined with X-ray diffraction and atomic force microscopy (AFM) revealed the characteristic oligomeric amyloid conformation of the U-turn beta-strand-turn-beta-strand motif stacked in parallel and stabilized by intermolecular interactions also shown by Abeta(9-40)/Abeta(17-42) and the CA150 WW domain. Here we use the K3 U-turn atomic coordinates and molecular dynamic (MD) simulations to model K3 channels in the membrane. Consistent with previous AFM imaging of other amyloids that show channel-like structures in the membrane, in the simulations K3 also forms ion channels with 3-6 loosely attached mobile subunits. We carry out AFM, single channel electrical recording, and fluorescence imaging experiments. AFM images display 3D ion channel topography with shapes, morphologies, and dimensions consistent with the theoretical model. Electrical conductance measurements indicate multiple single channel conductances, suggesting that various K3 oligomer sizes can constitute the channel structure. Fluorescence measurements in kidney cells show channel-mediated cell calcium uptake. These results suggest that the beta(2)m-induced DRA can be mediated by ion channels formed by its K3 fragment. Because the beta-strand-turn-beta-strand motif appears to be a universal amyloid feature, its ability to form ion channels further suggests that the motif may play a generic role in toxicity.
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Affiliation(s)
- Mirela Mustata
- Center for Nanomedicine and Department of Medicine, University of Chicago, Chicago, Illinois 60637, USA
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37
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Sorce B, Sabella S, Sandal M, Samorì B, Santino A, Cingolani R, Rinaldi R, Pompa PP. Single-molecule mechanical unfolding of amyloidogenic beta2-microglobulin: the force-spectroscopy approach. Chemphyschem 2009; 10:1471-7. [PMID: 19496082 DOI: 10.1002/cphc.200900220] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The recombinant production of a novel chimeric polyprotein is described. The new protein contains either wild-type beta(2)-microglobulin (beta(2)m) or its truncated variant (DeltaN6 beta(2)m) (see picture). Structural characterization is achieved by means of single-molecule force spectroscopy studies of specific beta(2)m regions which could be involved in amyloidogenesis.
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Affiliation(s)
- B Sorce
- National Nanotechnology Laboratory of INFM-CNR, Italian Institute of Technology, Via Arnesano 16, 73100 Lecce, Italy
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38
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Fang PS, Zhao JH, Liu HL, Liu KT, Chen JT, Tsai WB, Lin HY, Fang HW, Ho Y. Molecular dynamics simulations to investigate the relationship between the structural stability and amyloidogenesis of the wild-type and N-terminal hexapeptide deletion ΔN6 β2-microglobulin. MOLECULAR SIMULATION 2009. [DOI: 10.1080/08927020902818005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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39
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A generic mechanism of beta2-microglobulin amyloid assembly at neutral pH involving a specific proline switch. J Mol Biol 2009; 386:1312-26. [PMID: 19452600 DOI: 10.1016/j.jmb.2009.01.013] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although numerous measurements of amyloid assembly of different proteins under distinct conditions in vitro have been performed, the molecular mechanisms underlying the specific self-association of proteins into amyloid fibrils remain obscure. Elucidating the nature of the events that initiate amyloid formation remains a particularly difficult challenge because of the heterogeneity and transient nature of the species involved. Here, we have used site-directed mutagenesis to create five proline to glycine variants in the naturally amyloidogenic protein beta2-microglobulin (beta2m). One of these variants, P5G, allowed us to isolate and characterise an intermediate containing a non-native trans Pro32 backbone conformation, a feature that is known to be required for amyloid elongation at neutral pH. By analysing oligomerisation and amyloid formation using analytical size-exclusion chromatography, multi-angle static light-scattering, analytical ultracentrifugation, circular dichroism and thioflavin T fluorescence we reveal a pathway for beta2m amyloid assembly at pH 7.5 that does not require the addition of metal ions, detergents, co-solvents or other co-factors that have been used to facilitate amyloid formation at physiological pH and temperature. Assembly is shown to involve the transient formation of a non-native monomer containing a trans P32 backbone conformation. This is followed by the formation of dimeric species and higher molecular mass oligomers that accumulate before the development of amyloid fibrils. On the basis of these results, we propose a generic mechanism for beta2m fibrillogenesis at neutral pH that is consistent with the wide range of published studies of this protein. In this mechanism, amyloid formation is initiated by a specific cis to trans proline switch, the rate of which we show to be controlled by the amino acid sequence proximal to P32 and to the applied solution conditions.
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40
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Abstract
beta(2)-microglobulin (beta(2)m) is capable of forming amyloid in osteoarticular structures in kidney failure patients that undergo chronic hemodialysis treatment. Although sophisticated analytical methods have yielded comprehensive data about the conformation of the native protein both as a monomer and as the light chain of the type I major histocompatibility complex, the cause and mechanisms leading to the transformation of beta(2)m into amyloid deposits in patients with dialysis-related amyloidosis are unsettled. The impact on conformational stability of various truncations, cleavages, amino acid substitutions, and divalent cations, especially Cu(2+), however, are highly relevant for understanding beta(2)m unfolding pathways leading to amyloid formation. This review describes the current knowledge about such conformationally destabilizing and amyloidogenic factors and links these to the structure and function of beta(2)m in normal physiology and pathology. Tables listing modifications of beta(2)m found in amyloid from patients and a systematic overview of laboratory conditions conducive to beta(2)m-fibrillogenesis are also included.
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41
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42
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Bellotti V, Chiti F. Amyloidogenesis in its biological environment: challenging a fundamental issue in protein misfolding diseases. Curr Opin Struct Biol 2008; 18:771-9. [DOI: 10.1016/j.sbi.2008.10.001] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Accepted: 10/15/2008] [Indexed: 10/21/2022]
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43
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Ricagno S, Colombo M, Rosa MD, Sangiovanni E, Giorgetti S, Raimondi S, Bellotti V, Bolognesi M. DE loop mutations affect β2-microglobulin stability and amyloid aggregation. Biochem Biophys Res Commun 2008; 377:146-50. [DOI: 10.1016/j.bbrc.2008.09.108] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2008] [Accepted: 09/22/2008] [Indexed: 10/21/2022]
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Kim J, Motomiya Y, Ueda M, Nakamura M, Misumi Y, Saito S, Ikemizu S, Misumi S, Ota K, Shinriki S, Kai H, Ando Y. Role of conformational change in the C-terminus of beta2-microglobulin in dialysis-related amyloidosis. Ann Clin Biochem 2008; 45:489-95. [PMID: 18753422 DOI: 10.1258/acb.2008.008046] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND Beta(2)-microglobulin (beta(2)m) has been identified as the precursor protein of dialysis-related amyloidosis (DRA), which is a serious complication for haemodialysis (HD) patients. However, mechanisms underlying beta(2)m amyloid fibril formation remains to be elucidated. We previously demonstrated, in amyloid deposits from HD patients, a conformational isoform of beta(2)m with an unfolded C-terminus. However, no direct experiments have previously been performed to address whether unfolded beta(2)m in the C-terminus may be prone to form amyloid fibrils. METHODS To evaluate roles of C-terminal amino acids in beta(2)m-induced amyloid formation, we generated six types of recombinant beta(2)m with amino acid substitutions in the C-terminal region. To investigate their conformational change and amyloidogenicity, we measured circular dichroism spectra, the fluorescence intensity of tryptophan and thioflavin-T (ThT) of the recombinant beta(2)m. To analyse morphological change of beta(2)m, we performed electron microscopy (EM) on the samples with elevated ThT fluorescence intensity. We used ultrasonication to enhance beta(2)m destabilization of the protein. RESULTS Beta(2)M Trp95Leu and Arg97Ala showed conformational changes and increased their amyloidgenicity compared with beta(2)m wild-type (WT). With ultrasonication, beta(2)m Trp95Leu and Arg97Ala generated more amyloid fibrils than did beta(2)m WT even in physiological solution. EM showed that beta(2)m formed amorphous debris containing typical amyloid fibrils at 24 hours, when ThT fluorescence intensity was three-fold lower than that at six hours. CONCLUSIONS Conformational changes in the C-terminus of beta(2)m may play an important role in DRA and that ultrasonication is useful for analysis of beta(2)m amyloidogenesis.
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Affiliation(s)
- Jaemi Kim
- Department of Molecular Medicine, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto, Japan
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Chaudhary N, Singh S, Nagaraj R. Organic solvent mediated self-association of an amyloid forming peptide from β2-microglobulin: An atomic force microscopy study. Biopolymers 2008; 90:783-91. [DOI: 10.1002/bip.21087] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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46
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Esposito G, Ricagno S, Corazza A, Rennella E, Gümral D, Mimmi MC, Betto E, Pucillo CE, Fogolari F, Viglino P, Raimondi S, Giorgetti S, Bolognesi B, Merlini G, Stoppini M, Bolognesi M, Bellotti V. The Controlling Roles of Trp60 and Trp95 in β2-Microglobulin Function, Folding and Amyloid Aggregation Properties. J Mol Biol 2008; 378:887-97. [DOI: 10.1016/j.jmb.2008.03.002] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2007] [Revised: 02/28/2008] [Accepted: 03/02/2008] [Indexed: 10/22/2022]
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47
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Carazzone C, Colombo R, Quaglia M, Mangione P, Raimondi S, Giorgetti S, Caccialanza G, Bellotti V, De Lorenzi E. Sulfonated molecules that bind a partially structured species of β2-microglobulin also influence refolding and fibrillogenesis. Electrophoresis 2008; 29:1502-10. [DOI: 10.1002/elps.200700677] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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48
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Relini A, De Stefano S, Torrassa S, Cavalleri O, Rolandi R, Gliozzi A, Giorgetti S, Raimondi S, Marchese L, Verga L, Rossi A, Stoppini M, Bellotti V. Heparin strongly enhances the formation of beta2-microglobulin amyloid fibrils in the presence of type I collagen. J Biol Chem 2007; 283:4912-20. [PMID: 18056266 DOI: 10.1074/jbc.m702712200] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The tissue specificity of fibrillar deposition in dialysis-related amyloidosis is most likely associated with the peculiar interaction of beta2-microglobulin (beta2-m) with collagen fibers. However, other co-factors such as glycosaminoglycans might facilitate amyloid formation. In this study we have investigated the role of heparin in the process of collagen-driven amyloidogenesis. In fact, heparin is a well known positive effector of fibrillogenesis, and the elucidation of its potential effect in this type of amyloidosis is particularly relevant because heparin is regularly given to patients subject to hemodialysis to prevent blood clotting. We have monitored by atomic force microscopy the formation of beta2-m amyloid fibrils in the presence of collagen fibers, and we have discovered that heparin strongly accelerates amyloid deposition. The mechanism of this effect is still largely unexplained. Using dynamic light scattering, we have found that heparin promotes beta2-m aggregation in solution at pH 6.4. Morphology and structure of fibrils obtained in the presence of collagen and heparin are highly similar to those of natural fibrils. The fibril surface topology, investigated by limited proteolysis, suggests that the general assembly of amyloid fibrils grown under these conditions and in vitro at low pH is similar. The exposure of these fibrils to trypsin generates a cleavage at the C-terminal of lysine 6 and creates the 7-99 truncated form of beta2-m (DeltaN6beta2-m) that is a ubiquitous constituent of the natural beta2-m fibrils. The formation of this beta2-m species, which has a strong propensity to aggregate, might play an important role in the acceleration of local amyloid deposition.
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Affiliation(s)
- Annalisa Relini
- Department of Physics, University of Genoa, Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM), I-16146 Genoa, Italy
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49
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Borysik AJ, Morten IJ, Radford SE, Hewitt EW. Specific glycosaminoglycans promote unseeded amyloid formation from β2-microglobulin under physiological conditions. Kidney Int 2007; 72:174-81. [PMID: 17495865 DOI: 10.1038/sj.ki.5002270] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Dialysis-related amyloidosis (DRA) is a complication of hemodialysis where beta2-microglobulin (beta2m) forms plaques mainly in cartilaginous tissues. The tissue-specific deposition, along with a known intransigence of pure beta2m to form fibrils in vitro at neutral pH in the absence of preformed fibrillar seeds, suggests a role for factors within cartilage in enhancing amyloid formation from this protein. To identify these factors, we determined the ability of a derivative lacking the N-terminal six amino acids found in ex vivo beta2m amyloid deposits to form amyloid fibrils at pH 7.4 in the absence of fibrillar seeds. We show that the addition of the glycosaminoglycans (GAGs) chrondroitin-4 or 6-sulfate to fibril growth assays results in the spontaneous generation of amyloid-like fibrils. By contrast, no fibrils are observed over the same time course in the presence of hyaluronic acid, a nonsulfated GAG that is abundant in cartilaginous joints. Based on the observation that hyaluronic acid has no effect on fibril stability, while chrondroitin-6-sulfate decreases the rate of fibril disassembly, we propose that the latter GAG enhances amyloid formation by stabilizing the rare fibrils that form spontaneously. This leads to the accumulation of beta2m in fibrillar deposits. Our data rationalize the joint-specific deposition of beta2m amyloid in DRA, suggesting mechanisms by which amyloid formation may be promoted.
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Affiliation(s)
- A J Borysik
- Astbury Centre for Structural Molecular Biology, Institute of Molecular and Cellular Biology, University of Leeds, Leeds, UK
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50
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Giorgetti S, Stoppini M, Tennent GA, Relini A, Marchese L, Raimondi S, Monti M, Marini S, Østergaard O, Heegaard NHH, Pucci P, Esposito G, Merlini G, Bellotti V. Lysine 58-cleaved beta2-microglobulin is not detectable by 2D electrophoresis in ex vivo amyloid fibrils of two patients affected by dialysis-related amyloidosis. Protein Sci 2007; 16:343-9. [PMID: 17242436 PMCID: PMC2203293 DOI: 10.1110/ps.062563507] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The lysine 58 cleaved and truncated variant of beta(2)-microglobulin (DeltaK58-beta2m) is conformationally unstable and present in the circulation of a large percentage of patients on chronic hemodialysis, suggesting that it could play a role in the beta2-microglobulin (beta2m) amyloid fibrillogenesis associated with dialysis-related amyloidosis (DRA). However, it has yet to be detected in the amyloid deposits of such patients. Here, we extracted amyloid fibrils, without denaturation or additional purification, from different amyloidotic tissues of two unrelated individuals suffering from DRA, and characterized them by high-sensitivity bidimensional gel electrophoresis (2D-PAGE), immunoblotting, MALDI time-of-flight mass spectrometry, and protein sequencing. To confirm whether or not this species could be identified by our proteomic approaches, we mapped its location in 2D-PAGE, in mixtures of pure DeltaK58-beta2m, and extracts of amyloid fibrils from patients, to a discrete region of the gel distinct from other isoforms of beta2m. Using this approach, the two known principal isoforms found in beta2m amyloid were identified, namely, the full-length protein and the truncated species lacking six N-terminal amino acid residues (DeltaN6-beta2m). In contrast, we found no evidence for the presence of DeltaK58-beta2m.
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Affiliation(s)
- Sofia Giorgetti
- Department of Biochemistry, University of Pavia-Laboratori di Biotecnologie, IRCCS Policlinico San Matteo, via Taramelli 3b, 27100 Pavia, Italy
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