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Kuhn AJ, Chan K, Sajimon M, Yoo S, Balasco Serrão VH, Lee J, Abrams B, Nowick JS, Uversky VN, Wheeler C, Raskatov JA. Amyloid-α Peptide Formed through Alternative Processing of the Amyloid Precursor Protein Attenuates Alzheimer's Amyloid-β Toxicity via Cross-Chaperoning. J Am Chem Soc 2024; 146:2634-2645. [PMID: 38236059 DOI: 10.1021/jacs.3c11511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Amyloid aggregation is a key feature of Alzheimer's disease (AD) and a primary target for past and present therapeutic efforts. Recent research is making it increasingly clear that the heterogeneity of amyloid deposits, extending past the commonly targeted amyloid-β (Aβ), must be considered for successful therapy. We recently demonstrated that amyloid-α (Aα or p3), a C-terminal peptidic fragment of Aβ, aggregates rapidly to form amyloids and can expedite the aggregation of Aβ through seeding. Here, we advance the understanding of Aα biophysics and biology in several important ways. We report the first cryogenic electron microscopy (cryo-EM) structure of an Aα amyloid fibril, proving unambiguously that the peptide is fibrillogenic. We demonstrate that Aα induces Aβ to form amyloid aggregates that are less toxic than pure Aβ aggregates and use nuclear magnetic resonance spectroscopy (NMR) to provide insights into specific interactions between Aα and Aβ in solution. This is the first evidence that Aα can coassemble with Aβ and alter its biological effects at relatively low concentrations. Based on the above, we urge researchers in the field to re-examine the significance of Aα in AD.
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Affiliation(s)
- Ariel J Kuhn
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California 95064, United States
| | - Ka Chan
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California 95064, United States
| | - Maria Sajimon
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California 95064, United States
| | - Stan Yoo
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, United States
| | - Vitor Hugo Balasco Serrão
- Biomolecular Cryoelectron Microscopy Facility, University of California, Santa Cruz, Santa Cruz, California 95064, United States
| | - Jack Lee
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California 95064, United States
| | - Benjamin Abrams
- Department of Biomolecular Engineering, Life Sciences Microscopy Center, University of California, Santa Cruz, Santa Cruz, California 95064, United States
| | - James S Nowick
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, United States
| | - Vladimir N Uversky
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, 12901 Bruce B. Downs Boulevard, MDC07, Tampa, Florida 33612, United States
| | - Christopher Wheeler
- World Brain Mapping Foundation, Society for Brain Mapping & Therapeutics, 860 Via De La Paz, Suite E-1, Pacific Palisades, California 90272-3668, United States
- StemVax Therapeutics (Subsidiary of NovAccess Global), 8584 E. Washington Street #127, Chagrin Falls, Ohio 44023, United States
- StemVax Therapeutics (Subsidiary of NovAccess Global), 2265 E. Foothill Boulevard, Pasadena, California 91107, United States
- T-Neuro Pharma, 1451 Innovation Parkway SE, Suite 600, Albuquerque, New Mexico 87123, United States
- T-Neuro Pharma, P.O. Box 781, Aptos, California 95003, United States
| | - Jevgenij A Raskatov
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California 95064, United States
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Ortigosa-Pascual L, Leiding T, Linse S, Pálmadóttir T. Photo-Induced Cross-Linking of Unmodified α-Synuclein Oligomers. ACS Chem Neurosci 2023; 14:3192-3205. [PMID: 37621159 PMCID: PMC10485903 DOI: 10.1021/acschemneuro.3c00326] [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: 05/12/2023] [Accepted: 08/14/2023] [Indexed: 08/26/2023] Open
Abstract
Photo-induced cross-linking of unmodified proteins (PICUP) has been used in the past to study size distributions of protein assemblies. PICUP may, for example, overcome the significant experimental challenges related to the transient nature, heterogeneity, and low concentration of amyloid protein oligomers relative to monomeric and fibrillar species. In the current study, a reaction chamber was designed, produced, and used for PICUP reaction optimization in terms of reaction conditions and lighting time from ms to s. These efforts make the method more reproducible and accessible and enable the use of shorter reaction times compared to previous studies. We applied the optimized method to an α-synuclein aggregation time course to monitor the relative concentration and size distribution of oligomers over time. The data are compared to the time evolution of the fibril mass concentration, as monitored by thioflavin T fluorescence. At all time points, the smaller the oligomer, the higher its concentration observed after PICUP. Moreover, the total oligomer concentration is highest at short aggregation times, and the decline over time follows the disappearance of monomers. We can therefore conclude that these oligomers form from monomers.
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Affiliation(s)
- Lei Ortigosa-Pascual
- Department of Biochemistry and Structural
Biology, Lund University, 221 00 Lund, Sweden
| | - Thom Leiding
- Department of Biochemistry and Structural
Biology, Lund University, 221 00 Lund, Sweden
| | - Sara Linse
- Department of Biochemistry and Structural
Biology, Lund University, 221 00 Lund, Sweden
| | - Tinna Pálmadóttir
- Department of Biochemistry and Structural
Biology, Lund University, 221 00 Lund, Sweden
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Sánchez Y, Castillo C, Fuentealba J, Sáez-Orellana F, Burgos CF, López JJ, F de la Torre A, Jiménez CA. New Benzodihydrofuran Derivatives Alter the Amyloid β Peptide Aggregation: Strategies To Develop New Anti-Alzheimer Drugs. ACS Chem Neurosci 2023; 14:2590-2602. [PMID: 37480555 DOI: 10.1021/acschemneuro.2c00778] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/24/2023] Open
Abstract
Alzheimer's disease is a neurodegenerative disorder that is the leading cause of dementia in elderly patients. Amyloid-β peptide (1-42 oligomers) has been identified as a neurotoxic factor, triggering many neuropathologic events. In this study, 15 chalcones were synthesized employing the Claisen-Schmidt condensation reaction, starting from a compound derived from fomannoxine, a natural benzodihydrofuran whose neuroprotective activity has been proven and reported, and methyl aromatic ketones with diverse patterns of halogenated substitution. As a result, chalcones were obtained, with good to excellent reaction yields from 50 to 98%. Cytotoxicity of the compounds was assessed, and their cytoprotective effect against the toxicity associated with Aβ was evaluated on PC-12 cells. Out of the 15 chalcones obtained, only the 4-bromo substituted was cytotoxic at most tested concentrations. Three synthesized chalcones showed a cytoprotective effect against Aβ toxicity (over 37%). The 2,4,5-trifluoro substituted chalcone was the most promising series since it showed a cytoprotective impact with more than 60 ± 5% of recovery of cellular viability; however, 3-fluoro substituted compound also exhibited important values of recovery (50 ± 6%). The fluorine substitution pattern was shown to be more effective for cytoprotective activity. Specifically, substitution with fluorine in the 3,5-positions turned out to be particularly effective for cytoprotection. Furthermore, fluorinated compounds inhibited the aggregation rate of Aβ, suggesting a dual effect that can be the starting point of new molecules with therapeutic potential.
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Affiliation(s)
- Yaíma Sánchez
- Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad de Concepción, Concepcion 4130000, Chile
| | - Carolina Castillo
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepcion 4130000, Chile
| | - Jorge Fuentealba
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepcion 4130000, Chile
| | - Francisco Sáez-Orellana
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepcion 4130000, Chile
| | - Carlos Felipe Burgos
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepcion 4130000, Chile
| | - Jhon J López
- Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad de Concepción, Concepcion 4130000, Chile
| | - Alexander F de la Torre
- Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad de Concepción, Concepcion 4130000, Chile
| | - Claudio A Jiménez
- Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad de Concepción, Concepcion 4130000, Chile
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Kuhn AJ, Raskatov JA. A robust preparation method for the amyloidogenic and intrinsically disordered amyloid-α peptide. J Pept Sci 2022; 28:e3414. [PMID: 35484922 PMCID: PMC9452447 DOI: 10.1002/psc.3414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 04/26/2022] [Indexed: 11/10/2022]
Abstract
Recent findings suggest that amyloid-β (Aβ) may not be the only peptidic culprit for the cognitive decline observed in patients with Alzheimer's disease. A C-terminal fragment of Aβ, amyloid-α (Aα), also known as p3, has been shown to form amyloidogenic oligomers and fibrils more rapidly than Aβ. However, the insolubility and aggregation propensity of this 24-26-residue peptide make it exceptionally difficult to produce, purify, and subsequently study. This paper reports a reproducible, multi-step method for the purification and pre-treatment of Aα and related analogues, yielding 95%-99% pure peptides. We anticipate that the methods described herein will permit previously inaccessible biophysical and biological experiments that may be critical to understanding the role of this too long overlooked peptide in AD disease pathology.
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Affiliation(s)
- Ariel J. Kuhn
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Jevgenij A. Raskatov
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, USA
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Foley AR, Raskatov J. AN ENANTIOMERIC FRAGMENT PAIR (EFP) APPROACH FOR THE STUDY OF CELLULAR UPTAKE OF INTRINSICALLY DISORDERED PROTEINS. Chembiochem 2022; 23:e202200146. [PMID: 35417609 DOI: 10.1002/cbic.202200146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 04/10/2022] [Indexed: 11/10/2022]
Abstract
The study of intrinsically disordered and amyloidogenic proteins poses a major challenge to researchers: the propensity of the system to aggregate and to form amyloid fibrils and deposits . This intrinsic nature limits the way amyloids can be studied and increases the level of complexity of the techniques needed to study the system of interest. Recent reports suggest that cellular recognition and internalization of pre-fibrillary species of amyloidogenic peptides and proteins may initiate some of its toxic actions. Therefore, developing novels tools to facilitate the understanding and determination of the interactions between intrinsically disordered proteins and the cellular membrane is becoming increasingly valuable. Here, we present and propose an approach for the study of the interactions of intrinsically disordered proteins with the cellular surface based on the use of enantiomeric fragment pairs (EFPs). By following a stepwise methodology in which the amyloidogenic peptide or protein is fragmented into specific segments, we show how this approach can be exploited to differentiate between different types of cellular uptake, to determine the degree of receptor-mediated cellular internalization of intrinsically disordered peptides and proteins, and to pinpoint the specific regions within the amino acid sequence responsible for the cellular recognition. Adopting this approach overcomes aggregation-related challenges and offers a particularly well-suited platform for the elucidation of receptor-intermediated recognition, uptake, and toxicity.
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Affiliation(s)
| | - Jevgenij Raskatov
- UCSC, Chemistry and Biochemistry, 1156 High Street, 95064, Santa Cruz, UNITED STATES
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Foley AR, Raskatov JA. Understanding and controlling amyloid aggregation with chirality. Curr Opin Chem Biol 2021; 64:1-9. [PMID: 33610939 PMCID: PMC8368077 DOI: 10.1016/j.cbpa.2021.01.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 01/11/2021] [Accepted: 01/16/2021] [Indexed: 12/22/2022]
Abstract
Amyloid aggregation and human disease are inextricably linked. Examples include Alzheimer disease, Parkinson disease, and type II diabetes. While seminal advances on the mechanistic understanding of these diseases have been made over the last decades, controlling amyloid fibril formation still represents a challenge, and it is a subject of active research. In this regard, chiral modifications have increasingly been proved to offer a particularly well-suited approach toward accessing to previously unknown aggregation pathways and to provide with novel insights on the biological mechanisms of action of amyloidogenic peptides and proteins. Here, we summarize recent advances on how the use of mirror-image peptides/proteins and d-amino acid incorporations have helped modulate amyloid aggregation, offered new mechanistic tools to study cellular interactions, and allowed us to identify key positions within the peptide/protein sequence that influence amyloid fibril growth and toxicity.
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Affiliation(s)
- Alejandro R Foley
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Jevgenij A Raskatov
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, 95064, USA.
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Raskatov JA, Foley A, Louis JM, Yau WM, Tycko R. Constraints on the Structure of Fibrils Formed by a Racemic Mixture of Amyloid-β Peptides from Solid-State NMR, Electron Microscopy, and Theory. J Am Chem Soc 2021; 143:13299-13313. [PMID: 34375097 PMCID: PMC8456612 DOI: 10.1021/jacs.1c06339] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Previous studies have shown that racemic mixtures of 40- and 42-residue amyloid-β peptides (d,l-Aβ40 and d,l-Aβ42) form amyloid fibrils with accelerated kinetics and enhanced stability relative to their homochiral counterparts (l-Aβ40 and l-Aβ42), suggesting a "chiral inactivation" approach to abrogating the neurotoxicity of Aβ oligomers (Aβ-CI). Here we report a structural study of d,l-Aβ40 fibrils, using electron microscopy, solid-state nuclear magnetic resonance (NMR), and density functional theory (DFT) calculations. Two- and three-dimensional solid-state NMR spectra indicate molecular conformations in d,l-Aβ40 fibrils that resemble those in known l-Aβ40 fibril structures. However, quantitative measurements of 13C-13C and 15N-13C distances in selectively labeled d,l-Aβ40 fibril samples indicate a qualitatively different supramolecular structure. While cross-β structures in mature l-Aβ40 fibrils are comprised of in-register, parallel β-sheets, our data indicate antiparallel β-sheets in d,l-Aβ40 fibrils, with alternation of d and l molecules along the fibril growth direction, i.e., antiparallel "rippled sheet" structures. The solid-state NMR data suggest the coexistence of d,l-Aβ40 fibril polymorphs with three different registries of intermolecular hydrogen bonds within the antiparallel rippled sheets. DFT calculations support an energetic preference for antiparallel alignments of the β-strand segments identified by solid-state NMR. These results provide insight into the structural basis for Aβ-CI and establish the importance of rippled sheets in self-assembly of full-length, naturally occurring amyloidogenic peptides.
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Affiliation(s)
- Jevgenij A. Raskatov
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA
| | - Alejandro Foley
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA
| | - John M. Louis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA
| | - Wai-Ming Yau
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA
| | - Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA
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