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Varshavskaya KB, Mitkevich VA, Makarov AA, Barykin EP. Synthetic, Cell-Derived, Brain-Derived, and Recombinant β-Amyloid: Modelling Alzheimer's Disease for Research and Drug Development. Int J Mol Sci 2022; 23:ijms232315036. [PMID: 36499362 PMCID: PMC9738609 DOI: 10.3390/ijms232315036] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 11/26/2022] [Accepted: 11/29/2022] [Indexed: 12/02/2022] Open
Abstract
Alzheimer's disease (AD) is the most common cause of dementia in the elderly, characterised by the accumulation of senile plaques and tau tangles, neurodegeneration, and neuroinflammation in the brain. The development of AD is a pathological cascade starting according to the amyloid hypothesis with the accumulation and aggregation of the β-amyloid peptide (Aβ), which induces hyperphosphorylation of tau and promotes the pro-inflammatory activation of microglia leading to synaptic loss and, ultimately, neuronal death. Modelling AD-related processes is important for both studying the molecular basis of the disease and the development of novel therapeutics. The replication of these processes is often achieved with the use of a purified Aβ peptide. However, Aβ preparations obtained from different sources can have strikingly different properties. This review aims to compare the structure and biological effects of Aβ oligomers and aggregates of a higher order: synthetic, recombinant, purified from cell culture, or extracted from brain tissue. The authors summarise the applicability of Aβ preparations for modelling Aβ aggregation, neurotoxicity, cytoskeleton damage, receptor toxicity in vitro and cerebral amyloidosis, synaptic plasticity disruption, and cognitive impairment in vivo and ex vivo. Further, the paper discusses the causes of the reported differences in the effect of Aβ obtained from the sources mentioned above. This review points to the importance of the source of Aβ for AD modelling and could help researchers to choose the optimal way to model the Aβ-induced abnormalities.
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Yang S, Zhang Q, Yang H, Shi H, Dong A, Wang L, Yu S. Progress in infrared spectroscopy as an efficient tool for predicting protein secondary structure. Int J Biol Macromol 2022; 206:175-187. [PMID: 35217087 DOI: 10.1016/j.ijbiomac.2022.02.104] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 02/14/2022] [Accepted: 02/17/2022] [Indexed: 12/21/2022]
Abstract
Infrared (IR) spectroscopy is a highly sensitive technique that provides complete information on chemical compositions. The IR spectra of proteins or peptides give rise to nine characteristic IR absorption bands. The amide I bands are the most prominent and sensitive vibrational bands and widely used to predict protein secondary structures. The interference of H2O absorbance is the greatest challenge for IR protein secondary structure prediction. Much effort has been made to reduce/eliminate the interference of H2O, simplify operation steps, and increase prediction accuracy. Progress in sampling and equipment has rendered the Fourier transform infrared (FTIR) technique suitable for determining the protein secondary structure in broader concentration ranges, greatly simplifying the operating steps. This review highlights the recent progress in sample preparation, data analysis, and equipment development of FTIR in A/T mode, with a focus on recent applications of FTIR spectroscopy in the prediction of protein secondary structure. This review also provides a brief introduction of the progress in ATR-FTIR for predicting protein secondary structure and discusses some combined IR methods, such as AFM-based IR spectroscopy, that are used to analyze protein structural dynamics and protein aggregation.
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Affiliation(s)
- Shouning Yang
- Zhejiang Provincial Key Laboratory of Advanced Mass Spectrometry and Molecular Analysis, Institute of Mass Spectrometry, School of Material Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, China
| | | | - Huayan Yang
- Zhejiang Provincial Key Laboratory of Advanced Mass Spectrometry and Molecular Analysis, Institute of Mass Spectrometry, School of Material Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Haimei Shi
- Zhejiang Provincial Key Laboratory of Advanced Mass Spectrometry and Molecular Analysis, Institute of Mass Spectrometry, School of Material Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Aichun Dong
- Department of Chemistry and Biochemistry, University of Northern Colorado, Greeley, CO, USA.
| | - Li Wang
- Kweichow Moutai Group, Renhuai, Guizhou 564501, China.
| | - Shaoning Yu
- Zhejiang Provincial Key Laboratory of Advanced Mass Spectrometry and Molecular Analysis, Institute of Mass Spectrometry, School of Material Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, China.
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3
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Fields CR, Dicke SS, Petti MK, Zanni MT, Lomont JP. A Different hIAPP Polymorph Is Observed in Human Serum Than in Aqueous Buffer: Demonstration of a New Method for Studying Amyloid Fibril Structure Using Infrared Spectroscopy. J Phys Chem Lett 2020; 11:6382-6388. [PMID: 32706257 PMCID: PMC7968077 DOI: 10.1021/acs.jpclett.0c01345] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
There is enormous interest in measuring amyloid fibril structures, but most structural studies measure fibril formation in vitro using aqueous buffer. Ideally, one would like to measure fibril structure and mechanism under more physiological conditions. Toward this end, we have developed a method for studying amyloid fibril structure in human serum. Our approach uses isotope labeling, antibody depletion of the most abundant proteins (albumin and IgG), and infrared spectroscopy to measure aggregation in human serum with reduced protein content. Reducing the nonamyloid protein content enables the measurements by decreasing background signals but retains the full composition of salts, sugars, metal ions, etc. that are naturally present but usually missing from in vitro studies. We demonstrate the method by measuring the two-dimensional infrared (2D IR) spectra of isotopically labeled human islet amyloid polypeptide (hIAPP or amylin). We find that the fibril structure of hIAPP formed in serum differs from that formed via aggregation in aqueous buffer at residues Gly24 and Ala25, which reside in the putative "amyloidogenic core" or FGAIL region of the sequence. The spectra are consistent with extended parallel stacks of strands consistent with β-sheet-like structure, rather than a partially disordered loop that forms in aqueous buffer. These experiments provide a new method for using infrared spectroscopy to monitor the structure of proteins under physiological conditions and reveal the formation of a significantly different polymorph structure in the most important region of hIAPP.
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Affiliation(s)
- Caitlyn R Fields
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Sidney S Dicke
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Megan K Petti
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Martin T Zanni
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Justin P Lomont
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
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4
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Hrubešová K, Fousková M, Habartová L, Fišar Z, Jirák R, Raboch J, Setnička V. Search for biomarkers of Alzheimer's disease: Recent insights, current challenges and future prospects. Clin Biochem 2019; 72:39-51. [PMID: 30953619 DOI: 10.1016/j.clinbiochem.2019.04.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 04/03/2019] [Indexed: 12/12/2022]
Abstract
Due to the trend of prolonged lifespan leading to higher incidence of age-related diseases, the demand for reliable biomarkers of dementia rises. In this review, we present novel biomarkers of high potential, especially those found in blood, urine or saliva, which could lead to a more comfortable patient experience and better time- and cost-effectivity, compared to the currently used diagnostic methods. We focus on biomarkers that might allow for the detection of Alzheimer's disease before its clinical manifestations. Such biomarkers might be helpful for better understanding the etiology of the disease and identifying its risk factors. Moreover, it could be a base for developing new treatment or at least help to prolong the presymptomatic stage in patients suffering from Alzheimer's disease. As potential candidates, we present, for instance, neurofilament light in both cerebrospinal fluid and blood plasma or amyloid β in plasma. Above all, we provide an overview of different approaches to the diagnostics, analyzing patient's biofluids as a whole using molecular spectroscopy. Infrared and Raman spectroscopy and especially chiroptical methods provide information not only on the chemical composition, but also on molecular structure. Therefore, these techniques are promising for the diagnostics of Alzheimer's disease, as the accumulation of amyloid β in abnormal conformation is one of the hallmarks of this disease.
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Affiliation(s)
- Kateřina Hrubešová
- Department of Analytical Chemistry, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague 6, Czech Republic
| | - Markéta Fousková
- Department of Analytical Chemistry, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague 6, Czech Republic
| | - Lucie Habartová
- Department of Analytical Chemistry, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague 6, Czech Republic
| | - Zdeněk Fišar
- Department of Psychiatry, First Faculty of Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 11, 120 00 Prague 2, Czech Republic
| | - Roman Jirák
- Department of Psychiatry, First Faculty of Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 11, 120 00 Prague 2, Czech Republic
| | - Jiří Raboch
- Department of Psychiatry, First Faculty of Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 11, 120 00 Prague 2, Czech Republic
| | - Vladimír Setnička
- Department of Analytical Chemistry, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague 6, Czech Republic.
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5
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Abstract
Fourier transform infrared (FTIR) spectroscopy has become one of the major techniques of structural characterization of proteins, peptides, and protein-membrane interactions. While the method does not have the capability of providing the precise, atomic-resolution molecular structure, it is exquisitely sensitive to conformational changes occurring in proteins upon functional transitions or intermolecular interactions. The sensitivity of vibrational frequencies to atomic masses has led to development of "isotope-edited" FTIR spectroscopy, where structural effects in two proteins, one unlabeled and the other labeled with a heavier stable isotope, such as 13C, are resolved simultaneously based on spectral downshift (separation) of the amide I band of the labeled protein. The same isotope effect is used to identify site-specific conformational changes in proteins by site-directed or segmental isotope labeling. Negligible light scattering in the infrared region provides an opportunity to study intermolecular interactions between large protein complexes, interactions of proteins and peptides with lipid vesicles, or protein-nucleic acid interactions without light scattering problems often encountered in ultraviolet spectroscopy. Attenuated total reflection FTIR (ATR-FTIR) is a surface-sensitive version of infrared spectroscopy that has proved useful in studying membrane proteins and lipids, protein-membrane interactions, mechanisms of interfacial enzymes, the structural features of membrane pore forming proteins and peptides, and much more. The purpose of this chapter was to provide a practical guide to analyze protein structure and protein-membrane interactions by FTIR and ATR-FTIR techniques, including procedures of sample preparation, measurements, and data analysis. Basic background information on FTIR spectroscopy, as well as some relatively new developments in structural and functional characterization of proteins and peptides in lipid membranes, is also presented.
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Affiliation(s)
- Suren A Tatulian
- Department of Physics, University of Central Florida, Orlando, FL, USA.
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6
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Morel B, Carrasco MP, Jurado S, Marco C, Conejero-Lara F. Dynamic micellar oligomers of amyloid beta peptides play a crucial role in their aggregation mechanisms. Phys Chem Chem Phys 2018; 20:20597-20614. [DOI: 10.1039/c8cp02685h] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Aβ40 and Aβ42 peptides form micellar precursors of amyloid nuclei contributing to important differences in their aggregation pathways.
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Affiliation(s)
- Bertrand Morel
- Departamento de Química Física e Instituto de Biotecnología
- Facultad de Ciencias
- Universidad de Granada
- 18071 Granada
- Spain
| | - Maria Paz Carrasco
- Departamento de Bioquímica y Biología Molecular I
- Facultad de Ciencias
- Universidad de Granada
- 18071 Granada
- Spain
| | - Samuel Jurado
- Departamento de Química Física e Instituto de Biotecnología
- Facultad de Ciencias
- Universidad de Granada
- 18071 Granada
- Spain
| | - Carmen Marco
- Departamento de Bioquímica y Biología Molecular I
- Facultad de Ciencias
- Universidad de Granada
- 18071 Granada
- Spain
| | - Francisco Conejero-Lara
- Departamento de Química Física e Instituto de Biotecnología
- Facultad de Ciencias
- Universidad de Granada
- 18071 Granada
- Spain
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7
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Kandel N, Zheng T, Huo Q, Tatulian SA. Membrane Binding and Pore Formation by a Cytotoxic Fragment of Amyloid β Peptide. J Phys Chem B 2017; 121:10293-10305. [PMID: 29039658 DOI: 10.1021/acs.jpcb.7b07002] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Amyloid β (Aβ) peptide contributes to Alzheimer's disease by a yet unidentified mechanism. In the brain tissue, Aβ occurs in various forms, including an undecapeptide Aβ25-35, which exerts a neurotoxic effect through the mitochondrial dysfunction and/or Ca2+-permeable pore formation in cell membranes. This work was aimed at the biophysical characterization of membrane binding and pore formation by Aβ25-35. Interaction of Aβ25-35 with anionic and zwitterionic membranes was analyzed by microelectrophoresis. In pore formation experiments, Aβ25-35 was incubated in aqueous buffer to form oligomers and added to Quin-2-loaded vesicles. Gradual increase in Quin-2 fluorescence was interpreted in terms of membrane pore formation by the peptide, Ca2+ influx, and binding to intravesicular Quin-2. The kinetics and magnitude of this process were used to evaluate the rate constant of pore formation, peptide-peptide association constants, and the oligomeric state of the pores. Decrease in membrane anionic charge and high ionic strength conditions significantly suppressed membrane binding and pore formation, indicating the importance of electrostatic interactions in these events. Circular dichroism spectroscopy showed that Aβ25-35 forms the most efficient pores in β-sheet conformation. The data are consistent with an oligo-oligomeric pore model composed of up to eight peptide units, each containing 6-8 monomers.
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Affiliation(s)
| | | | | | - Suren A Tatulian
- Department of Physics, University of Central Florida , Physical Sciences Bldg., Room 456, 4111 Libra Drive, Orlando, Florida 32816, United States
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8
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Zapadka KL, Becher FJ, Gomes Dos Santos AL, Jackson SE. Factors affecting the physical stability (aggregation) of peptide therapeutics. Interface Focus 2017; 7:20170030. [PMID: 29147559 DOI: 10.1098/rsfs.2017.0030] [Citation(s) in RCA: 175] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The number of biological therapeutic agents in the clinic and development pipeline has increased dramatically over the last decade and the number will undoubtedly continue to increase in the coming years. Despite this fact, there are considerable challenges in the development, production and formulation of such biologics particularly with respect to their physical stabilities. There are many cases where self-association to form either amorphous aggregates or highly structured fibrillar species limits their use. Here, we review the numerous factors that influence the physical stability of peptides including both intrinsic and external factors, wherever possible illustrating these with examples that are of therapeutic interest. The effects of sequence, concentration, pH, net charge, excipients, chemical degradation and modification, surfaces and interfaces, and impurities are all discussed. In addition, the effects of physical parameters such as pressure, temperature, agitation and lyophilization are described. We provide an overview of the structures of aggregates formed, as well as our current knowledge of the mechanisms for their formation.
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Affiliation(s)
| | - Frederik J Becher
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK
| | | | - Sophie E Jackson
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK
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9
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Major Reaction Coordinates Linking Transient Amyloid-β Oligomers to Fibrils Measured at Atomic Level. Biophys J 2017; 113:805-816. [PMID: 28834717 DOI: 10.1016/j.bpj.2017.06.068] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 06/22/2017] [Accepted: 06/22/2017] [Indexed: 11/22/2022] Open
Abstract
The structural underpinnings for the higher toxicity of the oligomeric intermediates of amyloidogenic peptides, compared to the mature fibrils, remain unknown at present. The transient nature and heterogeneity of the oligomers make it difficult to follow their structure. Here, using vibrational and solid-state nuclear magnetic resonance spectroscopy, and molecular dynamics simulations, we show that freely aggregating Aβ40 oligomers in physiological solutions have an intramolecular antiparallel configuration that is distinct from the intermolecular parallel β-sheet structure observed in mature fibrils. The intramolecular hydrogen-bonding network flips nearly 90°, and the two β-strands of each monomeric unit move apart, to give rise to the well-known intermolecular in-register parallel β-sheet structure in the mature fibrils. Solid-state nuclear magnetic resonance distance measurements capture the interstrand separation within monomer units during the transition from the oligomer to the fibril form. We further find that the D23-K28 salt-bridge, a major feature of the Aβ40 fibrils and a focal point of mutations linked to early onset Alzheimer's disease, is not detectable in the small oligomers. Molecular dynamics simulations capture the correlation between changes in the D23-K28 distance and the flipping of the monomer secondary structure between antiparallel and parallel β-sheet architectures. Overall, we propose interstrand separation and salt-bridge formation as key reaction coordinates describing the structural transition of the small Aβ40 oligomers to fibrils.
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10
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Use-dependent inhibition of glycine-activated chloride current in rat neurons by β-amyloid peptide pretreated with hexafluoroisopropanol. Neuroreport 2017; 28:579-583. [PMID: 28489663 DOI: 10.1097/wnr.0000000000000801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Hexafluoroisopropanol (HFIP) is a nonpolar organic solvent that is often used to prepare β-amyloid peptide (Aβ) samples. In this work, we compare the effects of two different species derived from synthetic Aβ1-42 and prepared without HFIP (Aβ) or using HFIP (Aβ/HFIP) on the glycine-activated chloride current (IGly). The experiments were conducted on the pyramidal neurons isolated from CA3 region of rat hippocampus. Transmembrane currents were recorded using a conventional patch-clamp technique in the whole-cell configuration. The IGly was induced by a step application of the agonist for 600 ms through glass capillary. Aβ or Aβ/HFIP was coapplied with glycine. The effects of the two species of the peptide have similar and distinctive features. Both substances caused a reduction in the peak amplitude and an acceleration of desensitization of the IGly. At the same time, the effect of Aβ/HFIP was found to develop and recover more slowly and required several repeated applications for its saturation (use dependence). The effect of Aβ/HFIP was voltage independent and equally pronounced at negative and positive membrane potentials. First, our results confirm that HFIP pretreatment may influence the properties of Aβ. Second, new information on the glycine receptor ability to interact with drugs in use-dependent mode was obtained.
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11
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Dammers C, Reiss K, Gremer L, Lecher J, Ziehm T, Stoldt M, Schwarten M, Willbold D. Pyroglutamate-Modified Amyloid-β(3-42) Shows α-Helical Intermediates before Amyloid Formation. Biophys J 2017; 112:1621-1633. [PMID: 28445753 PMCID: PMC5406372 DOI: 10.1016/j.bpj.2017.03.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 03/02/2017] [Accepted: 03/08/2017] [Indexed: 01/15/2023] Open
Abstract
Pyroglutamate-modified amyloid-β (pEAβ) has been described as a relevant Aβ species in Alzheimer's-disease-affected brains, with pEAβ (3-42) as a dominant isoform. Aβ (1-40) and Aβ (1-42) have been well characterized under various solution conditions, including aqueous solutions containing trifluoroethanol (TFE). To characterize structural properties of pEAβ (3-42) possibly underlying its drastically increased aggregation propensity compared to Aβ (1-42), we started our studies in various TFE-water mixtures and found striking differences between the two Aβ species. Soluble pEAβ (3-42) has an increased tendency to form β-sheet-rich structures compared to Aβ (1-42), as indicated by circular dichroism spectroscopy data. Kinetic assays monitored by thioflavin-T show drastically accelerated aggregation leading to large fibrils visualized by electron microscopy of pEAβ (3-42) in contrast to Aβ (1-42). NMR spectroscopy was performed for backbone and side-chain chemical-shift assignments of monomeric pEAβ (3-42) in 40% TFE solution. Although the difference between pEAβ (3-42) and Aβ (1-42) is purely N-terminal, it has a significant impact on the chemical environment of >20% of the total amino acid residues, as revealed by their NMR chemical-shift differences. Freshly dissolved pEAβ (3-42) contains two α-helical regions connected by a flexible linker, whereas the N-terminus remains unstructured. We found that these α-helices act as a transient intermediate to β-sheet and fibril formation of pEAβ (3-42).
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Affiliation(s)
- Christina Dammers
- Institute of Complex Systems (ICS-6) Structural Biochemistry, Forschungszentrum Jülich, Jülich, Germany
| | - Kerstin Reiss
- Institute of Complex Systems (ICS-6) Structural Biochemistry, Forschungszentrum Jülich, Jülich, Germany
| | - Lothar Gremer
- Institute of Complex Systems (ICS-6) Structural Biochemistry, Forschungszentrum Jülich, Jülich, Germany; Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Justin Lecher
- Institute of Complex Systems (ICS-6) Structural Biochemistry, Forschungszentrum Jülich, Jülich, Germany; Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Tamar Ziehm
- Institute of Complex Systems (ICS-6) Structural Biochemistry, Forschungszentrum Jülich, Jülich, Germany
| | - Matthias Stoldt
- Institute of Complex Systems (ICS-6) Structural Biochemistry, Forschungszentrum Jülich, Jülich, Germany; Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Melanie Schwarten
- Institute of Complex Systems (ICS-6) Structural Biochemistry, Forschungszentrum Jülich, Jülich, Germany
| | - Dieter Willbold
- Institute of Complex Systems (ICS-6) Structural Biochemistry, Forschungszentrum Jülich, Jülich, Germany; Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany.
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12
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Tomaselli S, Pagano K, D’Arrigo C, Molinari H, Ragona L. Evidence of Molecular Interactions of Aβ1-42 with N-Terminal Truncated Beta Amyloids by NMR. ACS Chem Neurosci 2017; 8:759-765. [PMID: 28135060 DOI: 10.1021/acschemneuro.6b00456] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Aβ peptides, the main protein components of Alzheimer's disease (AD) plaques, derive from a proteolytic cleavage of the amyloid precursor protein. Due to heterogeneous cleavage sites, a series of Aβ peptides, including the major and widely studied species Aβ1-40 (Aβ40) and Aβ1-42 (Aβ42), are produced. In addition to the C-terminal heterogeneity of Aβ peptides, significant amounts of N-terminal truncated (Aβ3-42) and pyroglutamate-modified amyloid-β peptides (AβpE3-42) have been identified in AD affected brains and shown to be more cytotoxic than unmodified Aβ peptides. Little is known about the properties of their mixtures with Aβ42. Nuclear Magnetic Resonance spectroscopy is here employed to investigate the interaction of N-truncated peptides with Aβ42 at different molar ratios. We highlight the critical concentration of N-truncated forms influencing the aggregation kinetics of Aβ42. We provide evidence, at residue level, that the C-terminal region of Aβ42 is the locus of transient specific interactions with highly aggregation prone N-truncated alloforms.
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Affiliation(s)
- Simona Tomaselli
- Istituto per lo Studio delle Macromolecole, CNR, Via Corti 12, 20133 Milan, Italy
| | - Katiuscia Pagano
- Istituto per lo Studio delle Macromolecole, CNR, Via Corti 12, 20133 Milan, Italy
| | - Cristina D’Arrigo
- Istituto per lo Studio delle Macromolecole, CNR, Via De Marini 6, 16149 Genoa, Italy
| | - Henriette Molinari
- Istituto per lo Studio delle Macromolecole, CNR, Via Corti 12, 20133 Milan, Italy
| | - Laura Ragona
- Istituto per lo Studio delle Macromolecole, CNR, Via Corti 12, 20133 Milan, Italy
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13
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Goldblatt G, Cilenti L, Matos JO, Lee B, Ciaffone N, Wang QX, Tetard L, Teter K, Tatulian SA. Unmodified and pyroglutamylated amyloid β peptides form hypertoxic hetero-oligomers of unique secondary structure. FEBS J 2017; 284:1355-1369. [PMID: 28294556 DOI: 10.1111/febs.14058] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 03/07/2017] [Accepted: 03/08/2017] [Indexed: 11/29/2022]
Abstract
Amyloid β (Aβ) peptide plays a major role in Alzheimer's disease (AD) and occurs in multiple forms, including pyroglutamylated Aβ (AβpE). Identification and characterization of the most cytotoxic Aβ species is necessary for advancement in AD diagnostics and therapeutics. While in brain tissue multiple Aβ species act in combination, structure/toxicity studies and immunotherapy trials have been focused on individual forms of Aβ. As a result, the molecular composition and the structural features of "toxic Aβ oligomers" have remained unresolved. Here, we have used a novel approach, hydration from gas phase coupled with isotope-edited Fourier transform infrared (FTIR) spectroscopy, to identify the prefibrillar assemblies formed by Aβ and AβpE and to resolve the structures of both peptides in combination. The peptides form unusual β-sheet oligomers stabilized by intramolecular H-bonding as opposed to intermolecular H-bonding in the fibrils. Time-dependent morphological changes in peptide assemblies have been visualized by atomic force microscopy. Aβ/AβpE hetero-oligomers exert unsurpassed cytotoxic effect on PC12 cells as compared to oligomers of individual peptides or fibrils. These findings lead to a novel concept that Aβ/AβpE hetero-oligomers, not just Aβ or AβpE oligomers, constitute the main neurotoxic conformation. The hetero-oligomers thus present a new biomarker that may be targeted for development of more efficient diagnostic and immunotherapeutic strategies to combat AD.
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Affiliation(s)
- Greg Goldblatt
- Biomedical Sciences Graduate Program, University of Central Florida, Orlando, FL, USA
| | - Lucia Cilenti
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Jason O Matos
- Biotechnology Graduate Program, University of Central Florida, Orlando, FL, USA
| | - Briana Lee
- Nanotechnology Graduate Program, NanoScience Technology Center, University of Central Florida, Orlando, FL, USA
| | - Nicholas Ciaffone
- Nanotechnology Graduate Program, NanoScience Technology Center, University of Central Florida, Orlando, FL, USA
| | - Qing X Wang
- Physics Graduate Program, College of Sciences, University of Central Florida, Orlando, FL, USA
| | - Laurene Tetard
- NanoScience Technology Center, University of Central Florida, Orlando, FL, USA.,Department of Physics, College of Sciences, University of Central Florida, Orlando, FL, USA
| | - Ken Teter
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Suren A Tatulian
- Department of Physics, College of Sciences, University of Central Florida, Orlando, FL, USA
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14
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Nagel-Steger L, Owen MC, Strodel B. An Account of Amyloid Oligomers: Facts and Figures Obtained from Experiments and Simulations. Chembiochem 2016; 17:657-76. [PMID: 26910367 DOI: 10.1002/cbic.201500623] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Indexed: 12/27/2022]
Abstract
The deposition of amyloid in brain tissue in the context of neurodegenerative diseases involves the formation of intermediate species-termed oligomers-of lower molecular mass and with structures that deviate from those of mature amyloid fibrils. Because these oligomers are thought to be primarily responsible for the subsequent disease pathogenesis, the elucidation of their structure is of enormous interest. Nevertheless, because of the high aggregation propensity and the polydispersity of oligomeric species formed by the proteins or peptides in question, the preparation of appropriate samples for high-resolution structural methods has proven to be rather difficult. This is why theoretical approaches have been of particular importance in gaining insights into possible oligomeric structures for some time. Only recently has it been possible to achieve some progress with regard to the experimentally based structural characterization of defined oligomeric species. Here we discuss how theory and experiment are used to determine oligomer structures and what can be done to improve the integration of the two disciplines.
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Affiliation(s)
- Luitgard Nagel-Steger
- Institute of Complex Systems: Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425, Jülich, Germany.,Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Universitätstrasse 1, 40225, Düsseldorf, Germany
| | - Michael C Owen
- Institute of Complex Systems: Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425, Jülich, Germany. .,Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, Universitätstrasse 1, 40225, Düsseldorf, Germany.
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