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Rinauro DJ, Chiti F, Vendruscolo M, Limbocker R. Misfolded protein oligomers: mechanisms of formation, cytotoxic effects, and pharmacological approaches against protein misfolding diseases. Mol Neurodegener 2024; 19:20. [PMID: 38378578 PMCID: PMC10877934 DOI: 10.1186/s13024-023-00651-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 08/17/2023] [Indexed: 02/22/2024] Open
Abstract
The conversion of native peptides and proteins into amyloid aggregates is a hallmark of over 50 human disorders, including Alzheimer's and Parkinson's diseases. Increasing evidence implicates misfolded protein oligomers produced during the amyloid formation process as the primary cytotoxic agents in many of these devastating conditions. In this review, we analyze the processes by which oligomers are formed, their structures, physicochemical properties, population dynamics, and the mechanisms of their cytotoxicity. We then focus on drug discovery strategies that target the formation of oligomers and their ability to disrupt cell physiology and trigger degenerative processes.
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Affiliation(s)
- Dillon J Rinauro
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Fabrizio Chiti
- Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50134, Florence, Italy
| | - Michele Vendruscolo
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
| | - Ryan Limbocker
- Department of Chemistry and Life Science, United States Military Academy, West Point, NY, 10996, USA.
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2
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Limbocker R, Staats R, Chia S, Ruggeri FS, Mannini B, Xu CK, Perni M, Cascella R, Bigi A, Sasser LR, Block NR, Wright AK, Kreiser RP, Custy ET, Meisl G, Errico S, Habchi J, Flagmeier P, Kartanas T, Hollows JE, Nguyen LT, LeForte K, Barbut D, Kumita JR, Cecchi C, Zasloff M, Knowles TPJ, Dobson CM, Chiti F, Vendruscolo M. Squalamine and Its Derivatives Modulate the Aggregation of Amyloid-β and α-Synuclein and Suppress the Toxicity of Their Oligomers. Front Neurosci 2021; 15:680026. [PMID: 34220435 PMCID: PMC8249941 DOI: 10.3389/fnins.2021.680026] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 04/16/2021] [Indexed: 12/14/2022] Open
Abstract
The aberrant aggregation of proteins is a key molecular event in the development and progression of a wide range of neurodegenerative disorders. We have shown previously that squalamine and trodusquemine, two natural products in the aminosterol class, can modulate the aggregation of the amyloid-β peptide (Aβ) and of α-synuclein (αS), which are associated with Alzheimer's and Parkinson's diseases. In this work, we expand our previous analyses to two squalamine derivatives, des-squalamine and α-squalamine, obtaining further insights into the mechanism by which aminosterols modulate Aβ and αS aggregation. We then characterize the ability of these small molecules to alter the physicochemical properties of stabilized oligomeric species in vitro and to suppress the toxicity of these aggregates to varying degrees toward human neuroblastoma cells. We found that, despite the fact that these aminosterols exert opposing effects on Aβ and αS aggregation under the conditions that we tested, the modifications that they induced to the toxicity of oligomers were similar. Our results indicate that the suppression of toxicity is mediated by the displacement of toxic oligomeric species from cellular membranes by the aminosterols. This study, thus, provides evidence that aminosterols could be rationally optimized in drug discovery programs to target oligomer toxicity in Alzheimer's and Parkinson's diseases.
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Affiliation(s)
- Ryan Limbocker
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
- Department of Chemistry & Life Science, United States Military Academy, West Point, NY, United States
| | - Roxine Staats
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Sean Chia
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Francesco S. Ruggeri
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
- Laboratory of Organic Chemistry, Wageningen University, Wageningen, Netherlands
- Laboratory of Physical Chemistry, Wageningen University, Wageningen, Netherlands
| | - Benedetta Mannini
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Catherine K. Xu
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Michele Perni
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Roberta Cascella
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Alessandra Bigi
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Liam R. Sasser
- Department of Chemistry & Life Science, United States Military Academy, West Point, NY, United States
| | - Natalie R. Block
- Department of Chemistry & Life Science, United States Military Academy, West Point, NY, United States
| | - Aidan K. Wright
- Department of Chemistry & Life Science, United States Military Academy, West Point, NY, United States
| | - Ryan P. Kreiser
- Department of Chemistry & Life Science, United States Military Academy, West Point, NY, United States
| | - Edward T. Custy
- Department of Chemistry & Life Science, United States Military Academy, West Point, NY, United States
| | - Georg Meisl
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Silvia Errico
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Johnny Habchi
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Patrick Flagmeier
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Tadas Kartanas
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Jared E. Hollows
- Department of Chemistry & Life Science, United States Military Academy, West Point, NY, United States
| | - Lam T. Nguyen
- Department of Chemistry & Life Science, United States Military Academy, West Point, NY, United States
| | - Kathleen LeForte
- Department of Chemistry & Life Science, United States Military Academy, West Point, NY, United States
| | | | - Janet R. Kumita
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Michael Zasloff
- Enterin Inc., Philadelphia, PA, United States
- MedStar Georgetown Transplant Institute, School of Medicine, Georgetown University, Washington, DC, United States
| | - Tuomas P. J. Knowles
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
- Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, United Kingdom
| | - Christopher M. Dobson
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Michele Vendruscolo
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
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3
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Kreiser RP, Wright AK, Block NR, Hollows JE, Nguyen LT, LeForte K, Mannini B, Vendruscolo M, Limbocker R. Therapeutic Strategies to Reduce the Toxicity of Misfolded Protein Oligomers. Int J Mol Sci 2020; 21:ijms21228651. [PMID: 33212787 PMCID: PMC7696907 DOI: 10.3390/ijms21228651] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 11/04/2020] [Accepted: 11/05/2020] [Indexed: 02/07/2023] Open
Abstract
The aberrant aggregation of proteins is implicated in the onset and pathogenesis of a wide range of neurodegenerative disorders, including Alzheimer’s and Parkinson’s diseases. Mounting evidence indicates that misfolded protein oligomers produced as intermediates in the aggregation process are potent neurotoxic agents in these diseases. Because of the transient and heterogeneous nature of these elusive aggregates, however, it has proven challenging to develop therapeutics that can effectively target them. Here, we review approaches aimed at reducing oligomer toxicity, including (1) modulating the oligomer populations (e.g., by altering the kinetics of aggregation by inhibiting, enhancing, or redirecting the process), (2) modulating the oligomer properties (e.g., through the size–hydrophobicity–toxicity relationship), (3) modulating the oligomer interactions (e.g., by protecting cell membranes by displacing oligomers), and (4) reducing oligomer toxicity by potentiating the protein homeostasis system. We analyze examples of these complementary approaches, which may lead to the development of compounds capable of preventing or treating neurodegenerative disorders associated with protein aggregation.
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Affiliation(s)
- Ryan P. Kreiser
- Department of Chemistry and Life Science, United States Military Academy, West Point, NY 10996, USA; (R.P.K.); (A.K.W.); (N.R.B.); (J.E.H.); (L.T.N.); (K.L.)
| | - Aidan K. Wright
- Department of Chemistry and Life Science, United States Military Academy, West Point, NY 10996, USA; (R.P.K.); (A.K.W.); (N.R.B.); (J.E.H.); (L.T.N.); (K.L.)
| | - Natalie R. Block
- Department of Chemistry and Life Science, United States Military Academy, West Point, NY 10996, USA; (R.P.K.); (A.K.W.); (N.R.B.); (J.E.H.); (L.T.N.); (K.L.)
| | - Jared E. Hollows
- Department of Chemistry and Life Science, United States Military Academy, West Point, NY 10996, USA; (R.P.K.); (A.K.W.); (N.R.B.); (J.E.H.); (L.T.N.); (K.L.)
| | - Lam T. Nguyen
- Department of Chemistry and Life Science, United States Military Academy, West Point, NY 10996, USA; (R.P.K.); (A.K.W.); (N.R.B.); (J.E.H.); (L.T.N.); (K.L.)
| | - Kathleen LeForte
- Department of Chemistry and Life Science, United States Military Academy, West Point, NY 10996, USA; (R.P.K.); (A.K.W.); (N.R.B.); (J.E.H.); (L.T.N.); (K.L.)
| | - Benedetta Mannini
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK;
| | - Michele Vendruscolo
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK;
- Correspondence: (M.V.); (R.L.)
| | - Ryan Limbocker
- Department of Chemistry and Life Science, United States Military Academy, West Point, NY 10996, USA; (R.P.K.); (A.K.W.); (N.R.B.); (J.E.H.); (L.T.N.); (K.L.)
- Correspondence: (M.V.); (R.L.)
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4
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Boi L, Pisanu A, Palmas MF, Fusco G, Carboni E, Casu MA, Satta V, Scherma M, Janda E, Mocci I, Mulas G, Ena A, Spiga S, Fadda P, De Simone A, Carta AR. Modeling Parkinson's Disease Neuropathology and Symptoms by Intranigral Inoculation of Preformed Human α-Synuclein Oligomers. Int J Mol Sci 2020; 21:E8535. [PMID: 33198335 PMCID: PMC7696693 DOI: 10.3390/ijms21228535] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/04/2020] [Accepted: 11/09/2020] [Indexed: 12/21/2022] Open
Abstract
The accumulation of aggregated α-synuclein (αSyn) is a hallmark of Parkinson's disease (PD). Current evidence indicates that small soluble αSyn oligomers (αSynOs) are the most toxic species among the forms of αSyn aggregates, and that size and topological structural properties are crucial factors for αSynOs-mediated toxicity, involving the interaction with either neurons or glial cells. We previously characterized a human αSynO (H-αSynO) with specific structural properties promoting toxicity against neuronal membranes. Here, we tested the neurotoxic potential of these H-αSynOs in vivo, in relation to the neuropathological and symptomatic features of PD. The H-αSynOs were unilaterally infused into the rat substantia nigra pars compacta (SNpc). Phosphorylated αSyn (p129-αSyn), reactive microglia, and cytokine levels were measured at progressive time points. Additionally, a phagocytosis assay in vitro was performed after microglia pre-exposure to αsynOs. Dopaminergic loss, motor, and cognitive performances were assessed. H-αSynOs triggered p129-αSyn deposition in SNpc neurons and microglia and spread to the striatum. Early and persistent neuroinflammatory responses were induced in the SNpc. In vitro, H-αSynOs inhibited the phagocytic function of microglia. H-αsynOs-infused rats displayed early mitochondrial loss and abnormalities in SNpc neurons, followed by a gradual nigrostriatal dopaminergic loss, associated with motor and cognitive impairment. The intracerebral inoculation of structurally characterized H-αSynOs provides a model of progressive PD neuropathology in rats, which will be helpful for testing neuroprotective therapies.
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Affiliation(s)
- Laura Boi
- Department of Biomedical Sciences, University of Cagliari, 09042 Cagliari, Italy; (L.B.); (M.F.P.); (E.C.); (V.S.); (M.S.); (A.E.); (P.F.)
| | | | - Maria Francesca Palmas
- Department of Biomedical Sciences, University of Cagliari, 09042 Cagliari, Italy; (L.B.); (M.F.P.); (E.C.); (V.S.); (M.S.); (A.E.); (P.F.)
| | - Giuliana Fusco
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, CB2 1EW Cambridge, UK;
| | - Ezio Carboni
- Department of Biomedical Sciences, University of Cagliari, 09042 Cagliari, Italy; (L.B.); (M.F.P.); (E.C.); (V.S.); (M.S.); (A.E.); (P.F.)
| | - Maria Antonietta Casu
- CNR Institute of Translational Pharmacology, 09010 Cagliari, Italy; (M.A.C.); (I.M.)
| | - Valentina Satta
- Department of Biomedical Sciences, University of Cagliari, 09042 Cagliari, Italy; (L.B.); (M.F.P.); (E.C.); (V.S.); (M.S.); (A.E.); (P.F.)
| | - Maria Scherma
- Department of Biomedical Sciences, University of Cagliari, 09042 Cagliari, Italy; (L.B.); (M.F.P.); (E.C.); (V.S.); (M.S.); (A.E.); (P.F.)
| | - Elzbieta Janda
- Department of Health Sciences, Magna Graecia University, 88100 Catanzaro, Italy;
| | - Ignazia Mocci
- CNR Institute of Translational Pharmacology, 09010 Cagliari, Italy; (M.A.C.); (I.M.)
| | - Giovanna Mulas
- Department of Life and Environmental Sciences, University of Cagliari, 09126 Cagliari, Italy; (G.M.); (S.S.)
| | - Anna Ena
- Department of Biomedical Sciences, University of Cagliari, 09042 Cagliari, Italy; (L.B.); (M.F.P.); (E.C.); (V.S.); (M.S.); (A.E.); (P.F.)
| | - Saturnino Spiga
- Department of Life and Environmental Sciences, University of Cagliari, 09126 Cagliari, Italy; (G.M.); (S.S.)
| | - Paola Fadda
- Department of Biomedical Sciences, University of Cagliari, 09042 Cagliari, Italy; (L.B.); (M.F.P.); (E.C.); (V.S.); (M.S.); (A.E.); (P.F.)
- CNR Institute of Neuroscience, 09042 Cagliari, Italy;
- Italian Neuroscience Institute (INN), 10126 Torino, Italy
| | - Alfonso De Simone
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
- Department of Pharmacy, University of Naples “Federico II”, 80131 Naples, Italy
| | - Anna R. Carta
- Department of Biomedical Sciences, University of Cagliari, 09042 Cagliari, Italy; (L.B.); (M.F.P.); (E.C.); (V.S.); (M.S.); (A.E.); (P.F.)
- Italian Neuroscience Institute (INN), 10126 Torino, Italy
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5
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Murgia F, Atzori L, Carboni E, Santoru ML, Hendren A, Pisanu A, Caboni P, Boi L, Fusco G, Carta AR. Metabolomics Fingerprint Induced by the Intranigral Inoculation of Exogenous Human Alpha-Synuclein Oligomers in a Rat Model of Parkinson's Disease. Int J Mol Sci 2020; 21:ijms21186745. [PMID: 32937957 PMCID: PMC7555976 DOI: 10.3390/ijms21186745] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/04/2020] [Accepted: 09/10/2020] [Indexed: 12/12/2022] Open
Abstract
Parkinson’s disease (PD) is considered a synucleinopathy because of the intraneuronal accumulation of aggregated α-synuclein (αSyn). Recent evidence points to soluble αSyn-oligomers (αSynO) as the main cytotoxic species responsible for cell death. Given the pivotal role of αSyn in PD, αSyn-based models are crucial for the investigation of toxic mechanisms and the identification of new therapeutic targets in PD. By using a metabolomics approach, we evaluated the metabolic profile of brain and serum samples of rats infused unilaterally with preformed human αSynOs (HαSynOs), or vehicle, into the substantia nigra pars compacta (SNpc). Three months postinfusion, the striatum was dissected for striatal dopamine (DA) measurements via High Pressure Liquid Chromatography (HPLC) analysis and mesencephalon and serum samples were collected for the evaluation of metabolite content via gas chromatography mass spectrometry analysis. Multivariate, univariate and correlation statistics were applied. A 40% decrease of DA content was measured in the HαSynO-infused striatum as compared to the contralateral and the vehicle-infused striata. Decreased levels of dehydroascorbic acid, myo-inositol, and glycine, and increased levels of threonine, were found in the mesencephalon, while increased contents of fructose and mannose, and a decrease in glycine and urea, were found in the serum of HαSynO-infused rats. The significant correlation between DA and metabolite content indicated that metabolic variations reflected the nigrostriatal degeneration. Collectively, the metabolomic fingerprint of HαSynO-infused rats points to an increase of oxidative stress markers, in line with PD neuropathology, and provides hints for potential biomarkers of PD.
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Affiliation(s)
- Federica Murgia
- Clinical Metabolomics Unit, Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria, Monserrato, 09042 Cagliari, Italy; (L.A.); (M.L.S.); (A.H.)
- Correspondence: (F.M.); (A.R.C.)
| | - Luigi Atzori
- Clinical Metabolomics Unit, Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria, Monserrato, 09042 Cagliari, Italy; (L.A.); (M.L.S.); (A.H.)
| | - Ezio Carboni
- Neuroscience Section, Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria, Monserrato, 09042 Cagliari, Italy; (E.C.); (L.B.)
| | - Maria Laura Santoru
- Clinical Metabolomics Unit, Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria, Monserrato, 09042 Cagliari, Italy; (L.A.); (M.L.S.); (A.H.)
| | - Aran Hendren
- Clinical Metabolomics Unit, Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria, Monserrato, 09042 Cagliari, Italy; (L.A.); (M.L.S.); (A.H.)
- Faculty of Health and Medical Sciences, University of Surrey, London GU2 7XH, UK
| | - Augusta Pisanu
- CNR Institute of Neuroscience, Monserrato, 09042 Cagliari, Italy;
| | - Pierluigi Caboni
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria, Monserrato, 09042 Cagliari, Italy;
| | - Laura Boi
- Neuroscience Section, Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria, Monserrato, 09042 Cagliari, Italy; (E.C.); (L.B.)
| | - Giuliana Fusco
- Department of Chemistry, Centre for Misfolding Diseases, University of Cambridge, Cambridge CB2 1EW, UK;
| | - Anna R. Carta
- Neuroscience Section, Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria, Monserrato, 09042 Cagliari, Italy; (E.C.); (L.B.)
- Correspondence: (F.M.); (A.R.C.)
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6
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Limbocker R, Mannini B, Ruggeri FS, Cascella R, Xu CK, Perni M, Chia S, Chen SW, Habchi J, Bigi A, Kreiser RP, Wright AK, Albright JA, Kartanas T, Kumita JR, Cremades N, Zasloff M, Cecchi C, Knowles TPJ, Chiti F, Vendruscolo M, Dobson CM. Trodusquemine displaces protein misfolded oligomers from cell membranes and abrogates their cytotoxicity through a generic mechanism. Commun Biol 2020; 3:435. [PMID: 32792544 PMCID: PMC7426408 DOI: 10.1038/s42003-020-01140-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 07/07/2020] [Indexed: 12/21/2022] Open
Abstract
The onset and progression of numerous protein misfolding diseases are associated with the presence of oligomers formed during the aberrant aggregation of several different proteins, including amyloid-β (Aβ) in Alzheimer’s disease and α-synuclein (αS) in Parkinson’s disease. These small, soluble aggregates are currently major targets for drug discovery. In this study, we show that trodusquemine, a naturally-occurring aminosterol, markedly reduces the cytotoxicity of αS, Aβ and HypF-N oligomers to human neuroblastoma cells by displacing the oligomers from cell membranes in the absence of any substantial morphological and structural changes to the oligomers. These results indicate that the reduced toxicity results from a mechanism that is common to oligomers from different proteins, shed light on the origin of the toxicity of the most deleterious species associated with protein aggregation and suggest that aminosterols have the therapeutically-relevant potential to protect cells from the oligomer-induced cytotoxicity associated with numerous protein misfolding diseases. Limbocker et al. show that trodusquemine, an aminosterol, reduces the cytotoxicity of protein misfolded oligomers by displacing them from cell membranes in the absence of any overt structural/ morphological changes in them. This mechanism appears to be general, as they test it for oligomers of αS, Aβ and the model protein HypF-N to human neuroblastoma cells.
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Affiliation(s)
- Ryan Limbocker
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.,Department of Chemistry and Life Science, United States Military Academy, West Point, NY, 10996, USA
| | - Benedetta Mannini
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Francesco S Ruggeri
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Roberta Cascella
- Department of Experimental and Clinical Biomedical Science, University of Florence, 50134, Florence, Italy
| | - Catherine K Xu
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Michele Perni
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Sean Chia
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Serene W Chen
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Johnny Habchi
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Alessandra Bigi
- Department of Experimental and Clinical Biomedical Science, University of Florence, 50134, Florence, Italy
| | - Ryan P Kreiser
- Department of Chemistry and Life Science, United States Military Academy, West Point, NY, 10996, USA
| | - Aidan K Wright
- Department of Chemistry and Life Science, United States Military Academy, West Point, NY, 10996, USA
| | - J Alex Albright
- Department of Chemistry and Life Science, United States Military Academy, West Point, NY, 10996, USA
| | - Tadas Kartanas
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Janet R Kumita
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Nunilo Cremades
- Institute for Biocomputation and Physics of Complex Systems (BIFI)-Joint Unit BIFI-IQFR (CSIC), University of Zaragoza, 50018, Zaragoza, Spain
| | - Michael Zasloff
- MedStar-Georgetown Transplant Institute, Georgetown University School of Medicine, Washington, DC, 20010, USA
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Science, University of Florence, 50134, Florence, Italy
| | - Tuomas P J Knowles
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.,Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Science, University of Florence, 50134, Florence, Italy.
| | - Michele Vendruscolo
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
| | - Christopher M Dobson
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
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7
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Limbocker R, Mannini B, Cataldi R, Chhangur S, Wright AK, Kreiser RP, Albright JA, Chia S, Habchi J, Sormanni P, Kumita JR, Ruggeri FS, Dobson CM, Chiti F, Aprile FA, Vendruscolo M. Rationally Designed Antibodies as Research Tools to Study the Structure-Toxicity Relationship of Amyloid-β Oligomers. Int J Mol Sci 2020; 21:E4542. [PMID: 32630615 PMCID: PMC7352524 DOI: 10.3390/ijms21124542] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 06/12/2020] [Accepted: 06/15/2020] [Indexed: 12/14/2022] Open
Abstract
Alzheimer's disease is associated with the aggregation of the amyloid-β peptide (Aβ), resulting in the deposition of amyloid plaques in brain tissue. Recent scrutiny of the mechanisms by which Aβ aggregates induce neuronal dysfunction has highlighted the importance of the Aβ oligomers of this protein fragment. Because of the transient and heterogeneous nature of these oligomers, however, it has been challenging to investigate the detailed mechanisms by which these species exert cytotoxicity. To address this problem, we demonstrate here the use of rationally designed single-domain antibodies (DesAbs) to characterize the structure-toxicity relationship of Aβ oligomers. For this purpose, we use Zn2+-stabilized oligomers of the 40-residue form of Aβ (Aβ40) as models of brain Aβ oligomers and two single-domain antibodies (DesAb18-24 and DesAb34-40), designed to bind to epitopes at residues 18-24 and 34-40 of Aβ40, respectively. We found that the DesAbs induce a change in structure of the Zn2+-stabilized Aβ40 oligomers, generating a simultaneous increase in their size and solvent-exposed hydrophobicity. We then observed that these increments in both the size and hydrophobicity of the oligomers neutralize each other in terms of their effects on cytotoxicity, as predicted by a recently proposed general structure-toxicity relationship, and observed experimentally. These results illustrate the use of the DesAbs as research tools to investigate the biophysical and cytotoxicity properties of Aβ oligomers.
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Affiliation(s)
- Ryan Limbocker
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK; (B.M.); (R.C.); (S.C.); (S.C.); (J.H.); (P.S.); (J.R.K.); (F.S.R.); (C.M.D.)
- Department of Chemistry and Life Science, United States Military Academy, West Point, NY 10996, USA; (A.K.W.); (R.P.K.); (J.A.A.)
| | - Benedetta Mannini
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK; (B.M.); (R.C.); (S.C.); (S.C.); (J.H.); (P.S.); (J.R.K.); (F.S.R.); (C.M.D.)
| | - Rodrigo Cataldi
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK; (B.M.); (R.C.); (S.C.); (S.C.); (J.H.); (P.S.); (J.R.K.); (F.S.R.); (C.M.D.)
| | - Shianne Chhangur
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK; (B.M.); (R.C.); (S.C.); (S.C.); (J.H.); (P.S.); (J.R.K.); (F.S.R.); (C.M.D.)
| | - Aidan K. Wright
- Department of Chemistry and Life Science, United States Military Academy, West Point, NY 10996, USA; (A.K.W.); (R.P.K.); (J.A.A.)
| | - Ryan P. Kreiser
- Department of Chemistry and Life Science, United States Military Academy, West Point, NY 10996, USA; (A.K.W.); (R.P.K.); (J.A.A.)
| | - J. Alex Albright
- Department of Chemistry and Life Science, United States Military Academy, West Point, NY 10996, USA; (A.K.W.); (R.P.K.); (J.A.A.)
| | - Sean Chia
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK; (B.M.); (R.C.); (S.C.); (S.C.); (J.H.); (P.S.); (J.R.K.); (F.S.R.); (C.M.D.)
| | - Johnny Habchi
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK; (B.M.); (R.C.); (S.C.); (S.C.); (J.H.); (P.S.); (J.R.K.); (F.S.R.); (C.M.D.)
| | - Pietro Sormanni
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK; (B.M.); (R.C.); (S.C.); (S.C.); (J.H.); (P.S.); (J.R.K.); (F.S.R.); (C.M.D.)
| | - Janet R. Kumita
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK; (B.M.); (R.C.); (S.C.); (S.C.); (J.H.); (P.S.); (J.R.K.); (F.S.R.); (C.M.D.)
| | - Francesco S. Ruggeri
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK; (B.M.); (R.C.); (S.C.); (S.C.); (J.H.); (P.S.); (J.R.K.); (F.S.R.); (C.M.D.)
| | - Christopher M. Dobson
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK; (B.M.); (R.C.); (S.C.); (S.C.); (J.H.); (P.S.); (J.R.K.); (F.S.R.); (C.M.D.)
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Science, University of Florence, 50134 Florence, Italy;
| | - Francesco A. Aprile
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK; (B.M.); (R.C.); (S.C.); (S.C.); (J.H.); (P.S.); (J.R.K.); (F.S.R.); (C.M.D.)
| | - Michele Vendruscolo
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK; (B.M.); (R.C.); (S.C.); (S.C.); (J.H.); (P.S.); (J.R.K.); (F.S.R.); (C.M.D.)
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8
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Ghadami SA, Chia S, Ruggeri FS, Meisl G, Bemporad F, Habchi J, Cascella R, Dobson CM, Vendruscolo M, Knowles TPJ, Chiti F. Transthyretin Inhibits Primary and Secondary Nucleations of Amyloid-β Peptide Aggregation and Reduces the Toxicity of Its Oligomers. Biomacromolecules 2020; 21:1112-1125. [PMID: 32011129 PMCID: PMC7997117 DOI: 10.1021/acs.biomac.9b01475] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
![]()
Alzheimer’s
disease is associated with the deposition of
the amyloid-β peptide (Aβ) into extracellular senile plaques
in the brain. In vitro and in vivo observations have indicated that
transthyretin (TTR) acts as an Aβ scavenger in the brain, but
the mechanism has not been fully resolved. We have monitored the aggregation
process of Aβ40 by thioflavin T fluorescence, in
the presence or absence of different concentrations of preformed seed
aggregates of Aβ40, of wild-type tetrameric TTR (WT-TTR),
and of a variant engineered to be stable as a monomer (M-TTR). Both
WT-TTR and M-TTR were found to inhibit specific steps of the process
of Aβ40 fibril formation, which are primary and secondary
nucleations, without affecting the elongation of the resulting fibrils.
Moreover, the analysis shows that both WT-TTR and M-TTR bind to Aβ40 oligomers formed in the aggregation reaction and inhibit
their conversion into the shortest fibrils able to elongate. Using
biophysical methods, TTR was found to change some aspects of its overall
structure following such interactions with Aβ40 oligomers,
as well as with oligomers of Aβ42, while maintaining
its overall topology. Hence, it is likely that the predominant mechanism
by which TTR exerts its protective role lies in the binding of TTR
to the Aβ oligomers and in inhibiting primary and secondary
nucleation processes, which limits both the toxicity of Aβ oligomers
and the ability of the fibrils to proliferate.
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Affiliation(s)
- Seyyed Abolghasem Ghadami
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Section of Biochemistry, University of Florence, 50134 Florence, Italy
| | - Sean Chia
- Department of Chemistry, Centre for Misfolding Diseases, University of Cambridge, Cambridge CB2 1EW, U.K
| | - Francesco Simone Ruggeri
- Department of Chemistry, Centre for Misfolding Diseases, University of Cambridge, Cambridge CB2 1EW, U.K
| | - Georg Meisl
- Department of Chemistry, Centre for Misfolding Diseases, University of Cambridge, Cambridge CB2 1EW, U.K
| | - Francesco Bemporad
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Section of Biochemistry, University of Florence, 50134 Florence, Italy
| | - Johnny Habchi
- Department of Chemistry, Centre for Misfolding Diseases, University of Cambridge, Cambridge CB2 1EW, U.K
| | - Roberta Cascella
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Section of Biochemistry, University of Florence, 50134 Florence, Italy
| | - Christopher M Dobson
- Department of Chemistry, Centre for Misfolding Diseases, University of Cambridge, Cambridge CB2 1EW, U.K
| | - Michele Vendruscolo
- Department of Chemistry, Centre for Misfolding Diseases, University of Cambridge, Cambridge CB2 1EW, U.K
| | - Tuomas P J Knowles
- Department of Chemistry, Centre for Misfolding Diseases, University of Cambridge, Cambridge CB2 1EW, U.K.,Department of Physics, Cavendish Laboratory, 19 J. J. Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Section of Biochemistry, University of Florence, 50134 Florence, Italy
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9
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S-Homocysteinylation effects on transthyretin: worsening of cardiomyopathy onset. Biochim Biophys Acta Gen Subj 2020; 1864:129453. [DOI: 10.1016/j.bbagen.2019.129453] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 09/09/2019] [Accepted: 09/30/2019] [Indexed: 11/19/2022]
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10
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Partial Failure of Proteostasis Systems Counteracting TDP-43 Aggregates in Neurodegenerative Diseases. Int J Mol Sci 2019; 20:ijms20153685. [PMID: 31357627 PMCID: PMC6695586 DOI: 10.3390/ijms20153685] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 07/15/2019] [Accepted: 07/24/2019] [Indexed: 12/11/2022] Open
Abstract
Frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS) are progressive and fatal neurodegenerative disorders showing mislocalization and cytosolic accumulation of TDP-43 inclusions in the central nervous system. The decrease in the efficiency of the clearance systems in aging, as well as the presence of genetic mutations of proteins associated with cellular proteostasis in the familial forms of TDP-43 proteinopathies, suggest that a failure of these protein degradation systems is a key factor in the aetiology of TDP-43 associated disorders. Here we show that the internalization of human pre-formed TDP-43 aggregates in the murine neuroblastoma N2a cells promptly resulted in their ubiquitination and hyperphosphorylation by endogenous machineries, mimicking the post-translational modifications observed in patients. Moreover, our data identify mitochondria as the main responsible sites for the alteration of calcium homeostasis induced by TDP-43 aggregates, which, in turn, stimulates an increase in reactive oxygen species and, finally, caspase activation. The inhibition of TDP-43 proteostasis in the presence of selective inhibitors against the proteasome and macroautophagy systems revealed that these two systems are both severely involved in TDP-43 accumulation and have a strong influence on each other in neurodegenerative disorders associated with TDP-43.
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11
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Vivoli Vega M, Cascella R, Chen SW, Fusco G, De Simone A, Dobson CM, Cecchi C, Chiti F. The Toxicity of Misfolded Protein Oligomers Is Independent of Their Secondary Structure. ACS Chem Biol 2019; 14:1593-1600. [PMID: 31074957 DOI: 10.1021/acschembio.9b00324] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The self-assembly of proteins into structured fibrillar aggregates is associated with a range of neurodegenerative diseases, including Alzheimer's and Parkinson's diseases, in which an important cytotoxic role is thought to be played by small soluble oligomers accumulating during the aggregation process or released by mature fibrils. As the structural characteristics of such species and their links with toxicity are still not fully defined, we have compared six examples of preformed misfolded protein oligomers with different β-sheet content, as determined using Fourier transform infrared spectroscopy, and with different toxicity, as determined by three cellular readouts of cell viability. The results show the absence of any measurable correlation between the nature of their secondary structure and their cellular toxicity, both when comparing the six types of oligomers as a group and when comparing species in subgroups characterized by either the same size or the same exposure of hydrophobic moieties.
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Affiliation(s)
- Mirella Vivoli Vega
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, 50134 Florence, Italy
| | - Roberta Cascella
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, 50134 Florence, Italy
| | - Serene W Chen
- Department of Life Sciences, Imperial College London, London SW7 2AZ, U.K
| | - Giuliana Fusco
- Centre for Misfolding disease, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K
| | - Alfonso De Simone
- Department of Life Sciences, Imperial College London, London SW7 2AZ, U.K
| | - Christopher M. Dobson
- Centre for Misfolding disease, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, 50134 Florence, Italy
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, 50134 Florence, Italy
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12
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Trodusquemine enhances Aβ 42 aggregation but suppresses its toxicity by displacing oligomers from cell membranes. Nat Commun 2019; 10:225. [PMID: 30644384 PMCID: PMC6333784 DOI: 10.1038/s41467-018-07699-5] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 11/05/2018] [Indexed: 11/08/2022] Open
Abstract
Transient oligomeric species formed during the aggregation process of the 42-residue form of the amyloid-β peptide (Aβ42) are key pathogenic agents in Alzheimer's disease (AD). To investigate the relationship between Aβ42 aggregation and its cytotoxicity and the influence of a potential drug on both phenomena, we have studied the effects of trodusquemine. This aminosterol enhances the rate of aggregation by promoting monomer-dependent secondary nucleation, but significantly reduces the toxicity of the resulting oligomers to neuroblastoma cells by inhibiting their binding to the cellular membranes. When administered to a C. elegans model of AD, we again observe an increase in aggregate formation alongside the suppression of Aβ42-induced toxicity. In addition to oligomer displacement, the reduced toxicity could also point towards an increased rate of conversion of oligomers to less toxic fibrils. The ability of a small molecule to reduce the toxicity of oligomeric species represents a potential therapeutic strategy against AD.
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13
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Garai K, Posey AE, Li X, Buxbaum JN, Pappu RV. Inhibition of amyloid beta fibril formation by monomeric human transthyretin. Protein Sci 2018; 27:1252-1261. [PMID: 29498118 PMCID: PMC6032350 DOI: 10.1002/pro.3396] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 02/26/2018] [Accepted: 02/27/2018] [Indexed: 11/11/2022]
Abstract
Transthyretin (TTR) is a homotetrameric protein that is found in the plasma and cerebrospinal fluid. Dissociation of TTR tetramers sets off a downhill cascade of amyloid formation through polymerization of monomeric TTR. Interestingly, TTR has an additional, biologically relevant activity, which pertains to its ability to slow the progression of amyloid beta (Aβ) associated pathology in transgenic mice. In vitro, both TTR and a kinetically stable variant of monomeric TTR (M-TTR) inhibit the fibril formation of Aβ1-40/42 molecules. Published evidence suggests that tetrameric TTR binds preferentially to Aβ monomers, thus destabilizing fibril formation by depleting the pool of Aβ monomers from aggregating mixtures. Here, we investigate the effects of M-TTR on the in vitro aggregation of Aβ1-42 . Our data confirm previous observations that fibril formation of Aβ is suppressed in the presence of sub-stoichiometric amounts of M-TTR. Despite this, we find that sub-stoichiometric levels of M-TTR are not bona fide inhibitors of aggregation. Instead, they co-aggregate with Aβ to promote the formation of large, micron-scale insoluble, non-fibrillar amorphous deposits. Based on fluorescence correlation spectroscopy measurements, we find that M-TTR does not interact with monomeric Aβ. Two-color coincidence analysis of the fluorescence bursts of Aβ and M-TTR labeled with different fluorophores shows that M-TTR co-assembles with soluble Aβ aggregates and this appears to drive the co-aggregation into amorphous precipitates. Our results suggest that mimicking the co-aggregation activity with protein-based therapeutics might be a worthwhile strategy for rerouting amyloid beta peptides into inert, insoluble, and amorphous deposits.
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Affiliation(s)
- Kanchan Garai
- Department of Biomedical Engineering and Center for Biological Systems EngineeringWashington University in St. Louis, One Brookings Drive, Campus Box 1097St. LouisMissouri63130
- TIFR Centre for Interdisciplinary Sciences, 36/P Gopanpally Village, SerilingampallyHyderabad500019India
| | - Ammon E. Posey
- Department of Biomedical Engineering and Center for Biological Systems EngineeringWashington University in St. Louis, One Brookings Drive, Campus Box 1097St. LouisMissouri63130
| | - Xinyi Li
- Department of Molecular and Experimental MedicineThe Scripps Research Institute, 10550 North Torey Pines RoadLa JollaCalifornia92037
| | - Joel N. Buxbaum
- Department of Molecular and Experimental MedicineThe Scripps Research Institute, 10550 North Torey Pines RoadLa JollaCalifornia92037
| | - Rohit V. Pappu
- Department of Biomedical Engineering and Center for Biological Systems EngineeringWashington University in St. Louis, One Brookings Drive, Campus Box 1097St. LouisMissouri63130
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14
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Transthyretin Interferes with Aβ Amyloid Formation by Redirecting Oligomeric Nuclei into Non-Amyloid Aggregates. J Mol Biol 2018; 430:2722-2733. [PMID: 29890120 DOI: 10.1016/j.jmb.2018.06.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 05/25/2018] [Accepted: 06/04/2018] [Indexed: 12/26/2022]
Abstract
The pathological Aβ aggregates associated with Alzheimer's disease follow a nucleation-dependent path of formation. A nucleus represents an oligomeric assembly of Aβ peptides that acts as a template for subsequent incorporation of monomers to form a fibrillar structure. Nuclei can form de novo or via surface-catalyzed secondary nucleation, and the combined rates of elongation and nucleation control the overall rate of fibril formation. Transthyretin (TTR) obstructs Aβ fibril formation in favor of alternative non-fibrillar assemblies, but the mechanism behind this activity is not fully understood. This study shows that TTR does not significantly disturb fibril elongation; rather, it effectively interferes with the formation of oligomeric nuclei. We demonstrate that this interference can be modulated by altering the relative contribution of elongation and nucleation, and we show how TTR's effects can range from being essentially ineffective to almost complete inhibition of fibril formation without changing the concentration of TTR or monomeric Aβ.
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15
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Ghadami SA, Bemporad F, Sala BM, Tiana G, Ricagno S, Chiti F. FRET studies of various conformational states adopted by transthyretin. Cell Mol Life Sci 2017; 74:3577-3598. [PMID: 28478513 PMCID: PMC11107560 DOI: 10.1007/s00018-017-2533-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 04/15/2017] [Accepted: 05/02/2017] [Indexed: 01/01/2023]
Abstract
Transthyretin (TTR) is an extracellular protein able to deposit into well-defined protein aggregates called amyloid, in pathological conditions known as senile systemic amyloidosis, familial amyloid polyneuropathy, familial amyloid cardiomyopathy and leptomeningeal amyloidosis. At least three distinct partially folded states have been described for TTR, including the widely studied amyloidogenic state at mildly acidic pH. Here, we have used fluorescence resonance energy transfer (FRET) experiments in a monomeric variant of TTR (M-TTR) and in its W41F and W79F mutants, taking advantage of the presence of a unique, solvent-exposed, cysteine residue at position 10, that we have labelled with a coumarin derivative (DACM, acceptor), and of the two natural tryptophan residues at positions 41 and 79 (donors). Trp41 is located in an ideal position as it is one of the residues of β-strand C, whose degree of unfolding is debated. We found that the amyloidogenic state at low pH has the same FRET efficiency as the folded state at neutral pH in both M-TTR and W79F-M-TTR, indicating an unmodified Cys10-Trp41 distance. The partially folded state populated at low denaturant concentrations also has a similar FRET efficiency, but other spectroscopic probes indicate that it is distinct from the amyloidogenic state at acidic pH. By contrast, the off-pathway state accumulating transiently during refolding has a higher FRET efficiency, indicating non-native interactions that reduce the Cys10-Trp41 spatial distance, revealing a third distinct conformational state. Overall, our results clarify a negligible degree of unfolding of β-strand C in the formation of the amyloidogenic state and establish the concept that TTR is a highly plastic protein able to populate at least three distinct conformational states.
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Affiliation(s)
- Seyyed Abolghasem Ghadami
- Dipartimento di Scienze Biomediche Sperimentali e Cliniche "Mario Serio", Sezione di Scienze Biochimiche, Università degli Studi di Firenze, Viale Morgagni 50, 50134, Florence, Italy
| | - Francesco Bemporad
- Dipartimento di Scienze Biomediche Sperimentali e Cliniche "Mario Serio", Sezione di Scienze Biochimiche, Università degli Studi di Firenze, Viale Morgagni 50, 50134, Florence, Italy
| | - Benedetta Maria Sala
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133, Milan, Italy
| | - Guido Tiana
- Center for Complexity and Biosystems, Department of Physics, Università degli Studi di Milano and INFN, via Celoria 16, 20133, Milan, Italy
| | - Stefano Ricagno
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133, Milan, Italy
| | - Fabrizio Chiti
- Dipartimento di Scienze Biomediche Sperimentali e Cliniche "Mario Serio", Sezione di Scienze Biochimiche, Università degli Studi di Firenze, Viale Morgagni 50, 50134, Florence, Italy.
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16
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Cascella R, Fani G, Capitini C, Rusmini P, Poletti A, Cecchi C, Chiti F. Quantitative assessment of the degradation of aggregated TDP-43 mediated by the ubiquitin proteasome system and macroautophagy. FASEB J 2017; 31:5609-5624. [PMID: 28842427 DOI: 10.1096/fj.201700292rr] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 08/14/2017] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis and frontotemporal lobar degeneration with ubiquitin-positive inclusions are neurodegenerative disorders that share the cytosolic deposition of TDP-43 (TAR DNA-binding protein 43) in the CNS. TDP-43 is well known as being actively degraded by both the proteasome and macroautophagy. The well-documented decrease in the efficiency of these clearance systems in aging and neurodegeneration, as well as the genetic evidence that many of the familial forms of TDP-43 proteinopathies involve genes that are associated with them, suggest that a failure of these protein degradation systems is a major factor that contributes to the onset of TDP-43-associated disorders. Here, we inserted preformed human TDP-43 aggregates in the cytosol of murine NSC34 and N2a cells in diffuse form and observed their degradation under conditions in which exogenous TDP-43 is not expressed and endogenous nuclear TDP-43 is not recruited, thereby allowing a time zero to be established in TDP-43 degradation and to observe its disposal kinetically and analytically. TDP-43 degradation was observed in the absence and presence of selective inhibitors and small interfering RNAs against the proteasome and autophagy. We found that cytosolic diffuse aggregates of TDP-43 can be distinguished in 3 different classes on the basis of their vulnerability to degradation, which contributed to the definition-with previous reports-of a total of 6 distinct classes of misfolded TDP-43 species that range from soluble monomer to undegradable macroaggregates. We also found that the proteasome and macroautophagy-degradable pools of TDP-43 are fully distinguishable, rather than in equilibrium between them on the time scale required for degradation, and that a significant crosstalk exists between the 2 degradation processes.-Cascella, R., Fani, G., Capitini, C., Rusmini, P., Poletti, A., Cecchi, C., Chiti, F. Quantitative assessment of the degradation of aggregated TDP-43 mediated by the ubiquitin proteasome system and macroautophagy.
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Affiliation(s)
- Roberta Cascella
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Giulia Fani
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Claudia Capitini
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Paola Rusmini
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Centro di Eccellenza sulle Malattie Neurodegenerative, Università degli Studi di Milano, Milan, Italy
| | - Angelo Poletti
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Centro di Eccellenza sulle Malattie Neurodegenerative, Università degli Studi di Milano, Milan, Italy
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy;
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17
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Mannini B, Chiti F. Chaperones as Suppressors of Protein Misfolded Oligomer Toxicity. Front Mol Neurosci 2017; 10:98. [PMID: 28424588 PMCID: PMC5380756 DOI: 10.3389/fnmol.2017.00098] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 03/23/2017] [Indexed: 01/30/2023] Open
Abstract
Chaperones have long been recognized to play well defined functions such as to: (i) assist protein folding and promote formation and maintenance of multisubunit complexes; (ii) mediate protein degradation; (iii) inhibit protein aggregation; and (iv) promote disassembly of undesired aberrant protein aggregates. In addition to these well-established functions, it is increasingly clear that chaperones can also interact with aberrant protein aggregates, such as pre-fibrillar oligomers and fibrils, and inhibit their toxicity commonly associated with neurodegenerative diseases without promoting their disassembly. In particular, the evidence collected so far in different labs, exploiting different experimental approaches and using different chaperones and client aggregated proteins, indicates the existence of two distinct mechanisms of action mediated by the chaperones to neutralize the toxicity of aberrant proteins oligomers: (i) direct binding of the chaperones to the hydrophobic patches exposed on the oligomer/fibril surface, with resulting shielding or masking of the moieties responsible for the aberrant interactions with cellular targets; (ii) chaperone-mediated conversion of aberrant protein aggregates into large and more innocuous species, resulting in a decrease of their surface-to-volume ratio and diffusibility and in deposits more easily manageable by clearance mechanisms, such as autophagy. In this review article we will describe the in vitro and in vivo evidence supporting both mechanisms and how this results in a suppression of the detrimental effects caused by protein misfolded aggregates.
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Affiliation(s)
| | - Fabrizio Chiti
- Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of FlorenceFlorence, Italy
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18
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Buxbaum JN, Johansson J. Transthyretin and BRICHOS: The Paradox of Amyloidogenic Proteins with Anti-Amyloidogenic Activity for Aβ in the Central Nervous System. Front Neurosci 2017; 11:119. [PMID: 28360830 PMCID: PMC5350149 DOI: 10.3389/fnins.2017.00119] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 02/27/2017] [Indexed: 01/19/2023] Open
Abstract
Amyloid fibrils are physiologically insoluble biophysically specific β-sheet rich structures formed by the aggregation of misfolded proteins. In vivo tissue amyloid formation is responsible for more than 30 different disease states in humans and other mammals. One of these, Alzheimer's disease (AD), is the most common form of human dementia for which there is currently no definitive treatment. Amyloid fibril formation by the amyloid β-peptide (Aβ) is considered to be an underlying cause of AD, and strategies designed to reduce Aβ production and/or its toxic effects are being extensively investigated in both laboratory and clinical settings. Transthyretin (TTR) and proteins containing a BRICHOS domain are etiologically associated with specific amyloid diseases in the CNS and other organs. Nonetheless, it has been observed that TTR and BRICHOS structures are efficient inhibitors of Aβ fibril formation and toxicity in vitro and in vivo, raising the possibility that some amyloidogenic proteins, or their precursors, possess properties that may be harnessed for combating AD and other amyloidoses. Herein, we review properties of TTR and the BRICHOS domain and discuss how their abilities to interfere with amyloid formation may be employed in the development of novel treatments for AD.
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Affiliation(s)
- Joel N Buxbaum
- Department of Molecular and Experimental Medicine, The Scripps Research InstituteLa Jolla, CA, USA; Scintillon InstituteSan Diego, CA, USA
| | - Jan Johansson
- Division of Neurogeriatrics, Department of Neurobiology, Care Sciences, and Society (NVS), Center for Alzheimer Research, Karolinska Institutet Huddinge, Sweden
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Cascella R, Capitini C, Fani G, Dobson CM, Cecchi C, Chiti F. Quantification of the Relative Contributions of Loss-of-function and Gain-of-function Mechanisms in TAR DNA-binding Protein 43 (TDP-43) Proteinopathies. J Biol Chem 2016; 291:19437-48. [PMID: 27445339 DOI: 10.1074/jbc.m116.737726] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration with ubiquitin positive inclusions (FTLD-U) are two clinically distinct neurodegenerative conditions sharing a similar histopathology characterized by the nuclear clearance of TDP-43 and its associated deposition into cytoplasmic inclusions in different areas of the central nervous system. Given the concomitant occurrence of TDP-43 nuclear depletion and cytoplasmic accumulation, it has been proposed that TDP-43 proteinopathies originate from either a loss-of-function (LOF) mechanism, a gain-of-function (GOF) process, or both. We have addressed this issue by transfecting murine NSC34 and N2a cells with siRNA for endogenous murine TDP-43 and with human recombinant TDP-43 inclusion bodies (IBs). These two strategies allowed the depletion of nuclear TDP-43 and the accumulation of cytoplasmic TDP-43 aggregates to occur separately and independently. Endogenous and exogenous TDP-43 were monitored and quantified using both immunofluorescence and Western blotting analysis, and nuclear functional TDP-43 was measured by monitoring the sortilin 1 mRNA splicing activity. Various degrees of TDP-43 cytoplasmic accumulation and nuclear TDP-43 depletion were achieved and the resulting cellular viability was evaluated, leading to a quantitative global analysis on the relative effects of LOF and GOF on the overall cytotoxicity. These were found to be ∼55% and 45%, respectively, in both cell lines and using both readouts of cell toxicity, showing that these two mechanisms are likely to contribute apparently equally to the pathologies of ALS and FTLD-U.
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Affiliation(s)
- Roberta Cascella
- From the Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of Florence, V.le GB Morgagni 50, 50134 Florence, Italy and
| | - Claudia Capitini
- From the Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of Florence, V.le GB Morgagni 50, 50134 Florence, Italy and
| | - Giulia Fani
- From the Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of Florence, V.le GB Morgagni 50, 50134 Florence, Italy and
| | - Christopher M Dobson
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW United Kingdom
| | - Cristina Cecchi
- From the Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of Florence, V.le GB Morgagni 50, 50134 Florence, Italy and
| | - Fabrizio Chiti
- From the Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of Florence, V.le GB Morgagni 50, 50134 Florence, Italy and
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