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Abstract
Primary nucleation is the fundamental event that initiates the conversion of proteins from their normal physiological forms into pathological amyloid aggregates associated with the onset and development of disorders including systemic amyloidosis, as well as the neurodegenerative conditions Alzheimer's and Parkinson's diseases. It has become apparent that the presence of surfaces can dramatically modulate nucleation. However, the underlying physicochemical parameters governing this process have been challenging to elucidate, with interfaces in some cases having been found to accelerate aggregation, while in others they can inhibit the kinetics of this process. Here we show through kinetic analysis that for three different fibril-forming proteins, interfaces affect the aggregation reaction mainly through modulating the primary nucleation step. Moreover, we show through direct measurements of the Gibbs free energy of adsorption, combined with theory and coarse-grained computer simulations, that overall nucleation rates are suppressed at high and at low surface interaction strengths but significantly enhanced at intermediate strengths, and we verify these regimes experimentally. Taken together, these results provide a quantitative description of the fundamental process which triggers amyloid formation and shed light on the key factors that control this process.
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2
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Near-Wall Aggregation of Amyloidogenic Aβ 1-40 Peptide: Direct Observation by the FRET. Molecules 2021; 26:molecules26247590. [PMID: 34946672 PMCID: PMC8706126 DOI: 10.3390/molecules26247590] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 12/09/2021] [Accepted: 12/13/2021] [Indexed: 11/17/2022] Open
Abstract
The formation of amyloid fibrils is one of the variants of the self-organization of polypeptide chains. For the amyloid aggregation, the solution must be oversaturated with proteins. The interface of the liquid (solution) and solid (vessel walls) phases can trigger the adsorption of protein molecules, and the resulting oversaturation can initiate conformational transitions in them. In any laboratory experiment, we cannot exclude the presence of surfaces such as the walls of vessels, cuvettes, etc. However, in many works devoted to the study of amyloid formation, this feature is not considered. In our work, we investigated the behavior of the Aβ 1-40 peptide at the water–glass, water–quartz, and water–plastic interface. We carried out a series of simple experiments and showed that the Aβ 1-40 peptide is actively adsorbed on these surfaces, which leads to a significant interaction and aggregation of peptides. This means that the interface can be the place where the first amyloid nucleus appears. We suggest that this effect may also be one of the reasons for the difficulty of reproducing kinetic data when studying the aggregation of the amyloid of the Aβ 1-40 peptide and other amyloidogenic proteins
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The kinetics of islet amyloid polypeptide phase-separated system and hydrogel formation are critically influenced by macromolecular crowding. Biochem J 2021; 478:3025-3046. [PMID: 34313292 PMCID: PMC8370757 DOI: 10.1042/bcj20210384] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/19/2021] [Accepted: 07/26/2021] [Indexed: 11/17/2022]
Abstract
Many protein misfolding diseases (e.g. type II diabetes and Alzheimer's disease) are characterised by amyloid deposition. Human islet amyloid polypeptide (hIAPP, involved in type II diabetes) spontaneously undergoes liquid-liquid phase separation (LLPS) and a kinetically complex hydrogelation, both catalysed by hydrophobic-hydrophilic interfaces (e.g. air-water interface and/or phospholipids-water interfaces). Gelation of hIAPP phase-separated liquid droplets initiates amyloid aggregation and the formation of clusters of interconnected aggregates, which grow and fuse to eventually percolate the whole system. Droplet maturation into irreversible hydrogels via amyloid aggregation is thought to be behind the pathology of several diseases. Biological fluids contain a high volume fraction of macromolecules, leading to macromolecular crowding. Despite crowding agent addition in in vitro studies playing a significant role in changing protein phase diagrams, the mechanism underlying enhanced LLPS, and the effect(s) on stages beyond LLPS remain poorly or not characterised.We investigated the effect of macromolecular crowding and increased viscosity on the kinetics of hIAPP hydrogelation using rheology and the evolution of the system beyond LLPS by microscopy. We demonstrate that increased viscosity exacerbated the kinetic variability of hydrogelation and of the phase separated-aggregated system, whereas macromolecular crowding abolished heterogeneity. Increased viscosity also strengthened the gel meshwork and accelerated aggregate cluster fusion. In contrast, crowding either delayed cluster fusion onset (dextran) or promoted it (Ficoll). Our study highlights that an in vivo crowded environment would critically influence amyloid stages beyond LLPS and pathogenesis.
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Gamba P, Giannelli S, Staurenghi E, Testa G, Sottero B, Biasi F, Poli G, Leonarduzzi G. The Controversial Role of 24-S-Hydroxycholesterol in Alzheimer's Disease. Antioxidants (Basel) 2021; 10:antiox10050740. [PMID: 34067119 PMCID: PMC8151638 DOI: 10.3390/antiox10050740] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 04/29/2021] [Accepted: 05/03/2021] [Indexed: 01/19/2023] Open
Abstract
The development of Alzheimer’s disease (AD) is influenced by several events, among which the dysregulation of cholesterol metabolism in the brain plays a major role. Maintenance of brain cholesterol homeostasis is essential for neuronal functioning and brain development. To maintain the steady-state level, excess brain cholesterol is converted into the more hydrophilic metabolite 24-S-hydroxycholesterol (24-OHC), also called cerebrosterol, by the neuron-specific enzyme CYP46A1. A growing bulk of evidence suggests that cholesterol oxidation products, named oxysterols, are the link connecting altered cholesterol metabolism to AD. It has been shown that the levels of some oxysterols, including 27-hydroxycholesterol, 7β-hydroxycholesterol and 7-ketocholesterol, significantly increase in AD brains contributing to disease progression. In contrast, 24-OHC levels decrease, likely due to neuronal loss. Among the different brain oxysterols, 24-OHC is certainly the one whose role is most controversial. It is the dominant oxysterol in the brain and evidence shows that it represents a signaling molecule of great importance for brain function. However, numerous studies highlighted the potential role of 24-OHC in favoring AD development, since it promotes neuroinflammation, amyloid β (Aβ) peptide production, oxidative stress and cell death. In parallel, 24-OHC has been shown to exert several beneficial effects against AD progression, such as preventing tau hyperphosphorylation and Aβ production. In this review we focus on the current knowledge of the controversial role of 24-OHC in AD pathogenesis, reporting a detailed overview of the findings about its levels in different AD biological samples and its noxious or neuroprotective effects in the brain. Given the relevant role of 24-OHC in AD pathophysiology, its targeting could be useful for disease prevention or slowing down its progression.
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Chiang YL, Chang YJ, Chen YR, Hwang IS. Effects of Dissolved Gases on the Amyloid Fibril Morphology. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:516-523. [PMID: 33352048 DOI: 10.1021/acs.langmuir.0c03215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The onset or progression of numerous neurodegenerative diseases occurs due to aggregation of proteins that ultimately form fibrils. The assembly and morphology of fibrils are susceptible to environmental factors. In this work, we used atomic force microscopy (AFM) to investigate the effects of dissolved nitrogen and oxygen molecules on the morphology of fibrils formed by a hydrophobic amyloid peptide implicated in amyotrophic lateral sclerosis, 15 repeats of glycine-alanine, on a highly oriented pyrolytic graphite substrate. We started with preformed fibril solutions that were then diluted with buffers of different gas conditions, resulting in the aggregation of the fibrils into different morphologies that were revealed by AFM after adsorption on the substrate. Straight fibrils were observed in both degassed and ambient buffers, but a stronger lateral association was seen in degassed buffers. Smaller and softer fibrils were observed in O2-supersaturated buffers, and plaque-like fibril aggregates of considerably large size were evident in N2-supersaturated buffers. In overnight incubation experiments, we observed changes in both the morphology and height of the fibril aggregates, and their evolution varied with different gas conditions. These findings indicate that the gas type and concentration affect the aggregation of amyloid fibrils and may facilitate the development of biomaterial applications and treatments for amyloid-related diseases.
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Affiliation(s)
- Ya-Ling Chiang
- Institute of Physics, Academia Sinica, Nankang, Taipei 115, Taiwan
| | - Yu-Jen Chang
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Taiwan University and Academia Sinica, Taipei, 115, Taiwan
| | - Yun-Ru Chen
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Taiwan University and Academia Sinica, Taipei, 115, Taiwan
| | - Ing-Shouh Hwang
- Institute of Physics, Academia Sinica, Nankang, Taipei 115, Taiwan
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6
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Abstract
It has long been recognized that liquid interfaces, such as the air-water interface (AWI), can enhance the formation of protein fibrils. This makes liquid interfaces attractive templates for fibril formation but fully realizing this requires knowledge of protein behavior at interfaces, which is currently lacking. To address this, molecular dynamics simulation is used to investigate fragments of amyloid beta, a model fibril forming protein, at the air-water interface. At the air-water interface, the enrichment of aggregation-prone helical conformations provides a mechanism for the enhancement of fibrillation at interfaces. The conformational ensemble at the air-water interface was also considerably reduced compared to bulk solution due to the tendency of hydrophobic side chains partitioning into the air restricting the range of conformations. Little overlap between the conformational ensembles at the AWI and in the bulk solution was found, suggesting that AWI induces the formation of a different set of structures compared to bulk solution. The smaller Aβ(16-22) and Aβ(25-35) fragments show an increase in the propensity for an ordered secondary structure at the air-water interface but with a increased propensity for turn over other motifs, illustrating the importance of intra-protein interactions for stabilizing helical and extended conformations.
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Alvarez AB, Caruso B, Rodríguez PEA, Petersen SB, Fidelio GD. Aβ-Amyloid Fibrils Are Self-Triggered by the Interfacial Lipid Environment and Low Peptide Content. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:8056-8065. [PMID: 32551671 DOI: 10.1021/acs.langmuir.0c00468] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We studied the surface properties of Aβ(1-40) amyloid peptides mixed with 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) (liquid state) or 1,2-disteraoyl-phosphatidylcholine (DSPC) (solid state) phospholipids by using nanostructured lipid/peptide films (Langmuir monolayers). Pure Aβ(1-40) amyloid peptides form insoluble monolayers without forming fibril-like structures. In a lipid environment [phospholipid/Aβ(1-40) peptide mixtures], we observed that both miscibility and stability of the films depend on the peptide content. At low Aβ(1-40) amyloid peptide proportion (from 2.5 to 10% of peptide area proportion), we observed the formation of a fibril-like structure when mixed only with POPC lipids. The stability acquired by these mixed films is within 20-35 mN·m-1 compatible with the equivalent surface pressure postulated for natural biomembranes. Fibrils are clearly evidenced directly from the monolayers by using Brewster angle microscopy. The so-called nanostructured fibrils are thioflavin T positive when observed by fluorescence microscopy. The amyloid fibril network at the surface was also evidenced by atomic force microscopy when the films are transferred onto a mica support. Aβ(1-40) amyloid mixed with the solid DSPC lipid showed an immiscible behavior in all peptide proportions without fibril formation. We postulated that the amyloid fibrillogenesis at the membrane can be dynamically nano-self-triggered at the surface by the quality of the interfacial environment, that is, the physical state of the water-lipid interface and the relative content of amyloid protein present at the interface.
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Affiliation(s)
- Alain Bolaño Alvarez
- Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Cordoba X5000HUA, Argentina
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC, CONICET, Universidad Nacional de Córdoba, Cordoba X5000HUA, Argentina
| | - Benjamín Caruso
- Cátedra de Química Biológica, Departamento de Química, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba X5016GCA, Argentina
- Instituto de Investigaciones Biológicas y Tecnológicas (IIBYT), CONICET, Universidad Nacional de Córdoba, Córdoba X5016GCA, Argentina
| | - Pablo E A Rodríguez
- Ministerio de Ciencia y Tecnología de la Provincia de Córdoba, Cordoba X5004AAP, Argentina
| | - Steffen B Petersen
- Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg 9220, Denmark
| | - Gerardo D Fidelio
- Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Cordoba X5000HUA, Argentina
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC, CONICET, Universidad Nacional de Córdoba, Cordoba X5000HUA, Argentina
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Conformation change of α-synuclein(61-95) at the air-water interface and quantitative measurement of the tilt angle of the axis of its α-helix by multiple angle incidence resolution spectroscopy. Colloids Surf B Biointerfaces 2019; 183:110401. [DOI: 10.1016/j.colsurfb.2019.110401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/16/2019] [Accepted: 07/26/2019] [Indexed: 11/18/2022]
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9
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Cheung DL. The air-water interface stabilizes α-helical conformations of the insulin B-chain. J Chem Phys 2019. [DOI: 10.1063/1.5100253] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Affiliation(s)
- David L. Cheung
- School of Chemistry, National University of Ireland Galway, Galway, Ireland
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Two/three-dimensional interfacial properties of the novel peptide as a selective destroyer of biomembrane. Colloids Surf A Physicochem Eng Asp 2019. [DOI: 10.1016/j.colsurfa.2019.04.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Xu Z, Hao C, Xie B, Sun R. Effect of Fe 3O 4 Nanoparticles on Mixed POPC/DPPC Monolayers at Air-Water Interface. SCANNING 2019; 2019:5712937. [PMID: 30944689 PMCID: PMC6421766 DOI: 10.1155/2019/5712937] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 12/20/2018] [Accepted: 01/08/2019] [Indexed: 06/09/2023]
Abstract
Fe3O4 nanoparticles (NPs) as a commonly used carrier in targeted drug delivery are widely used to carry drugs for the treatment of diseases. However, the mechanism of action of between Fe3O4 NPs and biological membranes is still unclear. Therefore, this article reports the influence of hydrophilic and hydrophobic Fe3O4 NPs on mixed 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) that were studied using the Langmuir-Blodgett (LB) film technique and an atomic force microscope (AFM). From surface pressure-area (π-A) isotherms, we have calculated the compression modulus. The results showed that hydrophobic Fe3O4 NPs enlarged the liquid-expanded (LE) and liquid-condensed (LC) phase of the mixed POPC/DPPC monolayers. The compressibility modulus of the mixed POPC/DPPC monolayer increases for hydrophilic Fe3O4 NPs, but the opposite happens for the hydrophobic Fe3O4 NPs. The adsorption of hydrophobic Fe3O4 NPs in mixed POPC/DPPC monolayers was much more than the hydrophilic Fe3O4 NPs. The interaction of hydrophilic Fe3O4 NPs with the head polar group of the mixed lipids increased the attraction force among the molecules, while the interaction of hydrophobic Fe3O4 NPs with the tail chain of the mixed lipids enhanced the repulsive force. The morphology of the monolayers was observed by AFM for validating the inferred results. This study is of great help for the application of Fe3O4 NPs in biological systems.
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Affiliation(s)
- Zhuangwei Xu
- School of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062, China
| | - Changchun Hao
- School of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062, China
| | - Bin Xie
- School of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062, China
| | - Runguang Sun
- School of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062, China
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12
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Jean L, Brimijoin S, Vaux DJ. In vivo localization of human acetylcholinesterase-derived species in a β-sheet conformation at the core of senile plaques in Alzheimer's disease. J Biol Chem 2019; 294:6253-6272. [PMID: 30787102 DOI: 10.1074/jbc.ra118.006230] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 02/13/2019] [Indexed: 12/22/2022] Open
Abstract
Many neurodegenerative diseases are characterized by amyloid deposition. In Alzheimer's disease (AD), β-amyloid (Aβ) peptides accumulate extracellularly in senile plaques. The AD amyloid cascade hypothesis proposes that Aβ production or reduced clearance leads to toxicity. In contrast, the cholinergic hypothesis argues for a specific pathology of brain cholinergic pathways. However, neither hypothesis in isolation explains the pattern of AD pathogenesis. Evidence suggests that a connection exists between these two scenarios: the synaptic form of human acetylcholinesterase (hAChE-S) associates with plaques in AD brains; among hAChE variants, only hAChE-S enhances Aβ fibrillization in vitro and Aβ deposition and toxicity in vivo Only hAChE-S contains an amphiphilic C-terminal domain (T40, AChE575-614), with AChE586-599 homologous to Aβ and forming amyloid fibrils, which implicates T40 in AD pathology. We previously showed that the amyloid scavenger, insulin-degrading enzyme (IDE), generates T40-derived amyloidogenic species that, as a peptide mixture, seed Aβ fibrillization. Here, we characterized 11 peptides from a T40-IDE digest for β-sheet conformation, surfactant activity, fibrillization, and seeding capability. We identified residues important for amyloidogenicity and raised polyclonal antibodies against the most amyloidogenic peptide. These new antisera, alongside other specific antibodies, labeled sections from control, hAChE-S, hAPPswe, and hAChE-S/hAPPswe transgenic mice. We observed that hAChE-S β-sheet species co-localized with Aβ in mature plaque cores, surrounded by hAChE-S α-helical species. This observation provides the first in vivo evidence of the conformation of hAChE-S species within plaques. Our results may explain the role of hAChE-S in Aβ deposition and aggregation, as amyloidogenic hAChE-S β-sheet species might seed Aβ aggregation.
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Affiliation(s)
- Létitia Jean
- From the Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom and
| | - Stephen Brimijoin
- the Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota 55905
| | - David J Vaux
- From the Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom and
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13
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Sharma SK, Seven ES, Micic M, Li S, Leblanc RM. Surface Chemistry and Spectroscopic Study of a Cholera Toxin B Langmuir Monolayer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:2557-2564. [PMID: 29378405 DOI: 10.1021/acs.langmuir.7b04252] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this article, we explored the surface chemistry properties of a cholera toxin B (CTB) monolayer at the air-subphase interface and investigated the change in interfacial properties through in situ spectroscopy. The study showed that the impact of the blue shift was negligible, suggesting that the CTB molecules were minimally affected by the subphase molecules. The stability of the CTB monolayer was studied by maintaining the constant surface pressure for a long time and also by using the compression-decompression cycle experiments. The high stability of the Langmuir monolayer of CTB clearly showed that the driving force of CTB going to the amphiphilic membrane was its amphiphilic nature. In addition, no major change was detected in the various in situ spectroscopy results (such as UV-vis, fluorescence, and IR ER) of the CTB Langmuir monolayer with the increase in surface pressure. This indicates that no aggregation occurs in the Langmuir monolayer of CTB.
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Affiliation(s)
- Shiv K Sharma
- Department of Chemistry, University of Miami , 1301 Memorial Drive, Coral Gables, Florida 33146, United States
| | - Elif S Seven
- Department of Chemistry, University of Miami , 1301 Memorial Drive, Coral Gables, Florida 33146, United States
| | - Miodrag Micic
- MP Biomedicals LLC, 3 Hutton Center, Santa Ana, California 92707, United States
- Department of Engineering Design Technology, Cerritos College , 11110 Alondra Boulevard, Norwalk, California 90650, United States
| | - Shanghao Li
- MP Biomedicals LLC, 3 Hutton Center, Santa Ana, California 92707, United States
| | - Roger M Leblanc
- Department of Chemistry, University of Miami , 1301 Memorial Drive, Coral Gables, Florida 33146, United States
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Bénarouche A, Habchi J, Cagna A, Maniti O, Girard-Egrot A, Cavalier JF, Longhi S, Carrière F. Interfacial Properties of N TAIL, an Intrinsically Disordered Protein. Biophys J 2018; 113:2723-2735. [PMID: 29262365 DOI: 10.1016/j.bpj.2017.10.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 10/06/2017] [Accepted: 10/10/2017] [Indexed: 11/19/2022] Open
Abstract
Intrinsically disordered proteins (IDPs) lack stable secondary and tertiary structure under physiological conditions in the absence of their biological partners and thus exist as dynamic ensembles of interconverting conformers, often highly soluble in water. However, in some cases, IDPs such as the ones involved in neurodegenerative diseases can form protein aggregates and their aggregation process may be triggered by the interaction with membranes. Although the interfacial behavior of globular proteins has been extensively studied, experimental data on IDPs at the air/water (A/W) and water/lipid interfaces are scarce. We studied here the intrinsically disordered C-terminal domain of the Hendra virus nucleoprotein (NTAIL) and compared its interfacial properties to those of lysozyme that is taken as a model globular protein of similar molecular mass. Adsorption of NTAIL at the A/W interface was studied in the absence and presence of phospholipids using Langmuir films, polarization modulated-infrared reflection-absorption spectroscopy, and an automated drop tensiometer for interfacial tension and elastic modulus determination with oscillating bubbles. NTAIL showed a significant surface activity, with a higher adsorption capacity at the A/W interface and penetration into egg phosphatidylcholine monolayer compared to lysozyme. Whereas lysozyme remains folded upon compression of the protein layer at the A/W interface and shows a quasi-pure elastic behavior, NTAIL shows a much higher molecular area and forms a highly viscoelastic film with a high dilational modulus. To our knowledge, a new disorder-to-order transition is thus observed for the NTAIL protein that folds into an antiparallel β-sheet at the A/W interface and presents strong intermolecular interactions.
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Affiliation(s)
- Anaïs Bénarouche
- Aix-Marseille University, CNRS, Enzymologie Interfaciale et Physiologie de la Lipolyse UMR 7282, Marseille, France; TECLIS Scientific, Tassin, France
| | - Johnny Habchi
- Aix-Marseille University, CNRS, Architecture et Fonction des Macromolécules Biologiques (AFMB) UMR 7257, Marseille, France
| | | | - Ofelia Maniti
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS, INSA Lyon, CPE Lyon, UMR 5246 Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, Equipe Génie Enzymatique, Membranes Biomimétiques et Assemblages Supramoléculaires (GEMBAS), Villeurbanne, France
| | - Agnès Girard-Egrot
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS, INSA Lyon, CPE Lyon, UMR 5246 Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, Equipe Génie Enzymatique, Membranes Biomimétiques et Assemblages Supramoléculaires (GEMBAS), Villeurbanne, France
| | - Jean-François Cavalier
- Aix-Marseille University, CNRS, Enzymologie Interfaciale et Physiologie de la Lipolyse UMR 7282, Marseille, France
| | - Sonia Longhi
- Aix-Marseille University, CNRS, Architecture et Fonction des Macromolécules Biologiques (AFMB) UMR 7257, Marseille, France.
| | - Frédéric Carrière
- Aix-Marseille University, CNRS, Enzymologie Interfaciale et Physiologie de la Lipolyse UMR 7282, Marseille, France.
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15
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Maturana P, Martinez M, Noguera M, Santos N, Disalvo E, Semorile L, Maffia P, Hollmann A. Lipid selectivity in novel antimicrobial peptides: Implication on antimicrobial and hemolytic activity. Colloids Surf B Biointerfaces 2017; 153:152-159. [DOI: 10.1016/j.colsurfb.2017.02.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 01/10/2017] [Accepted: 02/04/2017] [Indexed: 10/20/2022]
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16
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Jean L, Lee CF, Hodder P, Hawkins N, Vaux DJ. Dynamics of the formation of a hydrogel by a pathogenic amyloid peptide: islet amyloid polypeptide. Sci Rep 2016; 6:32124. [PMID: 27535008 PMCID: PMC4989184 DOI: 10.1038/srep32124] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 08/02/2016] [Indexed: 11/24/2022] Open
Abstract
Many chronic degenerative diseases result from aggregation of misfolded polypeptides to form amyloids. Many amyloidogenic polypeptides are surfactants and their assembly can be catalysed by hydrophobic-hydrophilic interfaces (an air-water interface in-vitro or membranes in-vivo). We recently demonstrated the specificity of surface-induced amyloidogenesis but the mechanisms of amyloidogenesis and more specifically of adsorption at hydrophobic-hydrophilic interfaces remain poorly understood. Thus, it is critical to determine how amyloidogenic polypeptides behave at interfaces. Here we used surface tensiometry, rheology and electron microscopy to demonstrate the complex dynamics of gelation by full-length human islet amyloid polypeptide (involved in type II diabetes) both in the bulk solution and at hydrophobic-hydrophilic interfaces (air-water interface and phospholipids). We show that the hydrogel consists of a 3D supramolecular network of fibrils. We also assessed the role of solvation and dissected the evolution over time of the assembly processes. Amyloid gelation could have important pathological consequences for membrane integrity and cellular functions.
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Affiliation(s)
- Létitia Jean
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Chiu Fan Lee
- Department of Bioengineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | | | - Nick Hawkins
- Department of Zoology, University of Oxford, Oxford OX1 3PS, UK
| | - David J. Vaux
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
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17
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Hall D, Zhao R, So M, Adachi M, Rivas G, Carver JA, Goto Y. Recognizing and analyzing variability in amyloid formation kinetics: Simulation and statistical methods. Anal Biochem 2016; 510:56-71. [PMID: 27430932 DOI: 10.1016/j.ab.2016.07.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 07/11/2016] [Accepted: 07/13/2016] [Indexed: 12/24/2022]
Abstract
We examine the phenomenon of variability in the kinetics of amyloid formation and detail methods for its simulation, identification and analysis. Simulated data, reflecting intrinsic variability, were produced using rate constants, randomly sampled from a pre-defined distribution, as parameters in an irreversible nucleation-growth kinetic model. Simulated kinetic traces were reduced in complexity through description in terms of three characteristic parameters. Practical methods for assessing convergence of the reduced parameter distributions were introduced and a bootstrap procedure was applied to determine convergence for different levels of intrinsic variation. Statistical methods for assessing the significance of shifts in parameter distributions, relating to either change in parameter mean or distribution shape, were tested. Robust methods for analyzing and interpreting kinetic data possessing significant intrinsic variance will allow greater scrutiny of the effects of anti-amyloid compounds in drug trials.
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Affiliation(s)
- Damien Hall
- Research School of Chemistry, Australian National University, Acton ACT 2601, Australia; Institute for Protein Research, Osaka University, 3-1- Yamada-oka, Suita, Osaka 565-0871 Japan.
| | - Ran Zhao
- Research School of Chemistry, Australian National University, Acton ACT 2601, Australia
| | - Masatomo So
- Institute for Protein Research, Osaka University, 3-1- Yamada-oka, Suita, Osaka 565-0871 Japan
| | - Masayuki Adachi
- Institute for Protein Research, Osaka University, 3-1- Yamada-oka, Suita, Osaka 565-0871 Japan
| | - Germán Rivas
- Centro de Investigaciones Biológicas, CSIC, 28006 Madrid, Spain
| | - John A Carver
- Research School of Chemistry, Australian National University, Acton ACT 2601, Australia
| | - Yuji Goto
- Institute for Protein Research, Osaka University, 3-1- Yamada-oka, Suita, Osaka 565-0871 Japan
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18
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Cutró A, Hollmann A, Cejas J, Maturana P, Disalvo E, Frías M. Phenylalanine interaction with lipid monolayers at different pHs. Colloids Surf B Biointerfaces 2015; 135:504-509. [DOI: 10.1016/j.colsurfb.2015.07.059] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 06/18/2015] [Accepted: 07/21/2015] [Indexed: 11/16/2022]
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19
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Yi X, Zhang Y, Gong M, Yu X, Darabedian N, Zheng J, Zhou F. Ca2+ Interacts with Glu-22 of Aβ(1–42) and Phospholipid Bilayers to Accelerate the Aβ(1–42) Aggregation Below the Critical Micelle Concentration. Biochemistry 2015; 54:6323-32. [DOI: 10.1021/acs.biochem.5b00719] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Xinyao Yi
- Department
of Chemistry and Biochemistry, California State University, Los Angeles, California 90032, United States
- College
of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083, P. R. China
| | - Yi Zhang
- College
of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083, P. R. China
| | - Ming Gong
- Department
of Chemistry and Biochemistry, California State University, Los Angeles, California 90032, United States
| | - Xiang Yu
- Department
of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Narek Darabedian
- Department
of Chemistry and Biochemistry, California State University, Los Angeles, California 90032, United States
| | - Jie Zheng
- Department
of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Feimeng Zhou
- Department
of Chemistry and Biochemistry, California State University, Los Angeles, California 90032, United States
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20
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Shieh IC, Patel AR. Predicting the Agitation-Induced Aggregation of Monoclonal Antibodies Using Surface Tensiometry. Mol Pharm 2015. [DOI: 10.1021/acs.molpharmaceut.5b00089] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Ian C. Shieh
- Late Stage Pharmaceutical Development,
Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Ankit R. Patel
- Late Stage Pharmaceutical Development,
Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
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21
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Anthony NR, Mehta AK, Lynn DG, Berland KM. Mapping amyloid-β(16-22) nucleation pathways using fluorescence lifetime imaging microscopy. SOFT MATTER 2014; 10:4162-4172. [PMID: 24763698 DOI: 10.1039/c4sm00361f] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The cross-β peptide architecture is associated with numerous functional biomaterials and deleterious disease related aggregates. While these diverse and ubiquitous paracrystalline assemblies have been widely studied, a fundamental understanding of the nucleation and aggregation pathways to these structures remains elusive. Here we highlight a novel application of fluorescence lifetime imaging microscopy in characterising the critical stages of peptide aggregation. Using the central nucleating core of the amyloid-β (Aβ), Aβ(16-22), as a model cross-β system, and utilising a small fraction of rhodamine labelled peptide (Rh110-Aβ(17-22)), we map out a folding pathway from monomer to paracrystalline nanotube. Using this intrinsic fluorescence reporter, we demonstrate the effects of interfaces and evaporation on the nucleation of sub-critical concentration solutions, providing access to previously uncharacterised intermediate morphologies. Using fluorescence lifetime we follow the local peptide environment through the stages of nucleation and hydrophobic collapse, ending in a stable final structure. This work provides a metric for future implementations of measuring fluorescence lifetimes of intrinsic fluorescence reporters during the very dynamic processes relating to peptide nucleation and maturation.
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Affiliation(s)
- Neil R Anthony
- Department of Physics, Emory University, Atlanta, GA, USA.
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22
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Mosca S, Keller J, Azzouz N, Wagner S, Titz A, Seeberger PH, Brezesinski G, Hartmann L. Amphiphilic cationic β(3R3)-peptides: membrane active peptidomimetics and their potential as antimicrobial agents. Biomacromolecules 2014; 15:1687-95. [PMID: 24694059 DOI: 10.1021/bm500101w] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We introduce a novel class of membrane active peptidomimetics, the amphiphilic cationic β(3R3)-peptides, and evaluate their potential as antimicrobial agents. The design criteria, the building block and oligomer synthesis as well as a detailed structure-activity relationship (SAR) study are reported. Specifically, infrared reflection absorption spectroscopy (IRRAS) was employed to investigate structural features of amphiphilic cationic β(3R3)-peptide sequences at the hydrophobic/hydrophilic air/liquid interface. Furthermore, Langmuir monolayers of anionic and zwitterionic phospholipids have been used to model the interactions of amphiphilic cationic β(3R3)-peptides with prokaryotic and eukaryotic cellular membranes in order to predict their membrane selectivity and elucidate their mechanism of action. Lastly, antimicrobial activity was tested against Gram-positive M. luteus and S. aureus as well as against Gram-negative E. coli and P. aeruginosa bacteria along with testing hemolytic activity and cytotoxicity. We found that amphiphilic cationic β(3R3)-peptide sequences combine high and selective antimicrobial activity with exceptionally low cytotoxicity in comparison to values reported in the literature. Overall, this study provides further insights into the SAR of antimicrobial peptides and peptidomimetics and indicates that amphiphilic cationic β(3R3)-peptides are strong candidates for further development as antimicrobial agents with high therapeutic index.
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Affiliation(s)
- Simone Mosca
- Department of Biomolecular Systems and ‡Department of Interfaces, Research Campus Golm, Max Planck Institute of Colloids and Interfaces , 14424 Potsdam, Germany
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Mosca S, Dannehl C, Möginger U, Brezesinski G, Hartmann L. β(3R3)-Peptides: design and synthesis of novel peptidomimetics and their self-assembling properties at the air-water interface. Org Biomol Chem 2014; 11:5399-403. [PMID: 23860843 DOI: 10.1039/c3ob41135d] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
In this study we present the design and synthesis of a novel class of peptidomimetics, the β(3R3)-peptides. Via alternating directions of the amide bonds along β-peptide sequences, β(3R3)-peptides can potentially extend the structural space available to β-peptidic foldamers. Detailed analysis at the air-water interface shows strand conformations and the formation of sheet assemblies with different degrees of crystallinity. Furthermore β(3R3)-peptides exhibit a high proteolytic stability thus making them an interesting new class of peptidomimetics for biomedical applications.
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Affiliation(s)
- Simone Mosca
- Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany
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24
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Augusto MT, Hollmann A, Castanho MARB, Porotto M, Pessi A, Santos NC. Improvement of HIV fusion inhibitor C34 efficacy by membrane anchoring and enhanced exposure. J Antimicrob Chemother 2014; 69:1286-97. [PMID: 24464268 DOI: 10.1093/jac/dkt529] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVES The aim of the present work was to evaluate the interaction of two new HIV fusion inhibitors {HIVP3 [C34-polyethylene glycol (PEG)₄-cholesterol] and HIVP4 [(C34-PEG₄)₂-cholesterol]} with membrane model systems and human blood cells in order to clarify where and how the fusion inhibitors locate, allowing us to understand their mechanism of action at the molecular level, and which strategies may be followed to increase efficacy. METHODS Lipid vesicles with defined compositions were used for peptide partition and localization studies, based on the intrinsic fluorescence of HIVP3 and HIVP4. Lipid monolayers were employed in surface pressure studies. Finally, human erythrocytes and peripheral blood mononuclear cells (PBMCs) isolated from blood samples were used in dipole potential assays. RESULTS Membrane partition, dipole potential and surface pressure assays indicate that the new fusion inhibitors interact preferentially with cholesterol-rich liquid-ordered membranes, mimicking biological membrane microdomains known as lipid rafts. HIVP3 and HIVP4 are able to interact with human erythrocytes and PBMCs to a similar degree as a previously described simpler drug with monomeric C34 and lacking the PEG spacer, C34-cholesterol. However, the pocket-binding domain (PBD) of both HIVP3 and HIVP4 is more exposed to the aqueous environment than in C34-cholesterol. CONCLUSIONS The present data allow us to conclude that more efficient blocking of HIV entry results from the synergism between the membranotropic behaviour and the enhanced exposure of the PBD.
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Affiliation(s)
- Marcelo T Augusto
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
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25
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Abstract
Amyloid formation is a hallmark of protein misfolding diseases (e.g. Type II diabetes mellitus). The energetically unfavourable nucleation step of amyloidogenesis can be accelerated by seeding, during which pre-formed aggregates act as templates for monomer recruitment. Hydrophobic-hydrophilic interfaces [e.g. AWI (air-water interface)] can also catalyse amyloidogenesis due to the surfactant properties of amyloidogenic polypeptides. Using thioflavin T fluorescence and electron microscopy, we demonstrate that the outcome of seeding on human islet amyloid polypeptide amyloidogenesis is dependent upon whether the AWI is present or absent and is dictated by seed type. Seeding significantly inhibits (with AWI) or promotes (without AWI) plateau height compared with seedless controls; with short fibrils being more efficient seeds than their longer counterparts. Moreover, promotion of nucleation by increasing monomer concentrations can only be observed in the absence of an AWI. Using biophysical modelling, we suggest that a possible explanation for our results may reside in lateral interactions between seeds and monomers determining the fibril mass formed in seeded reactions at steady-state. Our results suggest that in vivo hydrophobic-hydrophilic interfaces (e.g. the presence of membranes and their turnover rate) may dictate the outcome of seeding during amyloidogenesis and that factors affecting the size of the pre-aggregate may be important.
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26
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Alhakamy NA, Kaviratna A, Berkland CJ, Dhar P. Dynamic measurements of membrane insertion potential of synthetic cell penetrating peptides. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:15336-49. [PMID: 24294979 PMCID: PMC3918496 DOI: 10.1021/la403370p] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Cell penetrating peptides (CPPs) have been established as excellent candidates for mediating drug delivery into cells. When designing synthetic CPPs for drug delivery applications, it is important to understand their ability to penetrate the cell membrane. In this paper, anionic or zwitterionic phospholipid monolayers at the air-water interface are used as model cell membranes to monitor the membrane insertion potential of synthetic CPPs. The insertion potential of CPPs having different cationic and hydrophobic amino acids were recorded using a Langmuir monolayer approach that records peptide adsorption to model membranes. Fluorescence microscopy was used to visualize alterations in phospholipid packing due to peptide insertion. All CPPs had the highest penetration potential in the presence of anionic phospholipids. In addition, two of three amphiphilic CPPs inserted into zwitterionic phospholipids, but none of the hydrophilic CPPs did. All the CPPs studied induced disruptions in phospholipid packing and domain morphology, which were most pronounced for amphiphilic CPPs. Overall, small changes to amino acids and peptide sequences resulted in dramatically different insertion potentials and membrane reorganization. Designers of synthetic CPPs for efficient intracellular drug delivery should consider small nuances in CPP electrostatic and hydrophobic properties.
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Affiliation(s)
- Nabil A. Alhakamy
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, USA 66047
| | - Anubhav Kaviratna
- Department of Chemical & Petroleum Engineering, University of Kansas, Lawrence, KS, USA 66047
| | - Cory J. Berkland
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, USA 66047
- Department of Chemical & Petroleum Engineering, University of Kansas, Lawrence, KS, USA 66047
| | - Prajnaparamita Dhar
- Department of Chemical & Petroleum Engineering, University of Kansas, Lawrence, KS, USA 66047
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27
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Chaari A, Horchani H, Frikha F, Verger R, Gargouri Y, Ladjimi M. Surface behavior of α-Synuclein and its interaction with phospholipids using the Langmuir monolayer technique: A comparison between monomeric and fibrillar α-Synuclein. Int J Biol Macromol 2013; 58:190-8. [DOI: 10.1016/j.ijbiomac.2013.03.057] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2013] [Revised: 03/12/2013] [Accepted: 03/23/2013] [Indexed: 11/16/2022]
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28
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Lipid interaction triggering Septin2 to assembly into β-sheet structures investigated by Langmuir monolayers and PM-IRRAS. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:1441-8. [PMID: 23416254 DOI: 10.1016/j.bbamem.2013.02.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 01/17/2013] [Accepted: 02/06/2013] [Indexed: 01/22/2023]
Abstract
The molecular mechanisms responsible for protein structural changes in the central nervous system leading to Alzheimer's disease are unknown, but there is evidence that a family of proteins known as septins may be involved. Septins are a conserved group of GTP-binding proteins which participate in various cellular processes, including polarity determination and membrane dynamics. SEPT1, SEPT4, and SEPT2 have been found in deposits known as neurofibrillary tangles and glial fibrils in Alzheimer's disease. In this study, we provide molecular-level information for the interaction of SEPT2 with Langmuir monolayers at the air/water interface, which are used as simplified membrane models. The high surface activity of SEPT2 causes it to adsorb onto distinct types of lipid Langmuir monolayers, namely dipalmitoylphosphatidylcholine and PtdIns(4,5)P2. However, the interaction with PtdIns(4,5)P2 is much stronger, not only leading to a higher adsorption, but also to SEPT2 remaining inserted within the membrane at high surface pressures. Most importantly, in situ polarization-modulated infrared reflection absorption spectroscopy results indicated that the native secondary structure of SEPT2 is preserved upon interacting with PtdIns(4,5)P2, but not when dipalmitoylphosphatidylcholine is at the air/water interface. Taken together, the results presented here suggest that the interaction between SEPT2 and the cell membrane may play an important role in the assembly of SEPT2 into amyloid-like fibers.
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29
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Lee CF, Bird S, Shaw M, Jean L, Vaux DJ. Combined effects of agitation, macromolecular crowding, and interfaces on amyloidogenesis. J Biol Chem 2012; 287:38006-19. [PMID: 22988239 PMCID: PMC3488071 DOI: 10.1074/jbc.m112.400580] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 09/17/2012] [Indexed: 11/06/2022] Open
Abstract
Amyloid formation and accumulation is a hallmark of protein misfolding diseases and is associated with diverse pathologies including type II diabetes and Alzheimer's disease (AD). In vitro, amyloidogenesis is widely studied in conditions that do not simulate the crowded and viscous in vivo environment. A high volume fraction of most biological fluids is occupied by various macromolecules, a phenomenon known as macromolecular crowding. For some amyloid systems (e.g. α-synuclein) and under shaking condition, the excluded volume effect of macromolecular crowding favors aggregation, whereas increased viscosity reduces the kinetics of these reactions. Amyloidogenesis can also be catalyzed by hydrophobic-hydrophilic interfaces, represented by the air-water interface in vitro and diverse heterogeneous interfaces in vivo (e.g. membranes). In this study, we investigated the effects of two different crowding polymers (dextran and Ficoll) and two different experimental conditions (with and without shaking) on the fibrilization of amyloid-β peptide, a major player in AD pathogenesis. Specifically, we demonstrate that, during macromolecular crowding, viscosity dominates over the excluded volume effect only when the system is spatially non homogeneous (i.e. an air-water interface is present). We also show that the surfactant activity of the crowding agents can critically influence the outcome of macromolecular crowding and that the structure of the amyloid species formed may depend on the polymer used. This suggests that, in vivo, the outcome of amyloidogenesis may be affected by both macromolecular crowding and spatial heterogeneity (e.g. membrane turn-over). More generally, our work suggests that any factors causing changes in crowding may be susceptibility factors in AD.
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Affiliation(s)
- Chiu Fan Lee
- the Max Planck Institute for the Physics of Complex Systems, Noethnitzerstr. 38, Dresden 01187, Germany, and
| | - Sarah Bird
- the Medical School, Medical Sciences Office, John Radcliffe Hospital, Oxford University Clinical School, Oxford, OX3 9DU, United Kingdom
| | - Michael Shaw
- From the Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Létitia Jean
- From the Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - David J. Vaux
- From the Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
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30
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Masters CL, Selkoe DJ. Biochemistry of amyloid β-protein and amyloid deposits in Alzheimer disease. Cold Spring Harb Perspect Med 2012; 2:a006262. [PMID: 22675658 PMCID: PMC3367542 DOI: 10.1101/cshperspect.a006262] [Citation(s) in RCA: 395] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Progressive cerebral deposition of the amyloid β-protein (Aβ) in brain regions serving memory and cognition is an invariant and defining feature of Alzheimer disease. A highly similar but less robust process accompanies brain aging in many nondemented humans, lower primates, and some other mammals. The discovery of Aβ as the subunit of the amyloid fibrils in meningocerebral blood vessels and parenchymal plaques has led to innumerable studies of its biochemistry and potential cytotoxic properties. Here we will review the discovery of Aβ, numerous aspects of its complex biochemistry, and current attempts to understand how a range of Aβ assemblies, including soluble oligomers and insoluble fibrils, may precipitate and promote neuronal and glial alterations that underlie the development of dementia. Although the role of Aβ as a key molecular factor in the etiology of Alzheimer disease remains controversial, clinical trials of amyloid-lowering agents, reviewed elsewhere in this book, are poised to resolve the question of its pathogenic primacy.
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Affiliation(s)
- Colin L Masters
- The Mental Health Research Institute, The University of Melbourne, Parkville 3010, Australia.
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31
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Jean L, Lee CF, Vaux DJ. Enrichment of amyloidogenesis at an air-water interface. Biophys J 2012; 102:1154-62. [PMID: 22404938 DOI: 10.1016/j.bpj.2012.01.041] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Revised: 01/20/2012] [Accepted: 01/24/2012] [Indexed: 11/16/2022] Open
Abstract
The aggregation of proteins or peptides into amyloid fibrils is a hallmark of protein misfolding diseases (e.g., Alzheimer's disease) and is under intense investigation. Many of the experiments performed are in vitro in nature and the samples under study are ordinarily exposed to diverse interfaces, e.g., the container wall and air. This naturally raises the question of how important interfacial effects are to amyloidogenesis. Indeed, it has already been recognized that many amyloid-forming peptides are surface-active. Moreover, it has recently been demonstrated that the presence of a hydrophobic interface can promote amyloid fibrillization, although the underlying mechanism is still unclear. Here, we combine theory, surface property measurements, and amyloid fibrillogenesis assays on islet amyloid polypeptide and amyloid-β peptide to demonstrate why, at experimentally relevant concentrations, the surface activity of the amyloid-forming peptides leads to enriched fibrillization at an air-water interface. Our findings indicate that the key that links these two seemingly different phenomena is the surface-active nature of the amyloid-forming species, which renders the surface concentration much higher than the corresponding critical fibrillar concentration. This subsequently leads to a substantial increase in fibrillization.
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Affiliation(s)
- Létitia Jean
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
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32
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Sanii B, Kudirka R, Cho A, Venkateswaran N, Olivier GK, Olson AM, Tran H, Harada RM, Tan L, Zuckermann RN. Shaken, not stirred: collapsing a peptoid monolayer to produce free-floating, stable nanosheets. J Am Chem Soc 2011; 133:20808-15. [PMID: 21939206 DOI: 10.1021/ja206199d] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Two-dimensional nanomaterials play a critical role in biology (e.g., lipid bilayers) and electronics (e.g., graphene) but are difficult to directly synthesize with a high level of precision. Peptoid nanosheet bilayers are a versatile synthetic platform for constructing multifunctional, precisely ordered two-dimensional nanostructures. Here we show that nanosheet formation occurs through an unusual monolayer intermediate at the air-water interface. Lateral compression of a self-assembled peptoid monolayer beyond a critical collapse pressure results in the irreversible production of nanosheets. An unusual thermodynamic cycle is employed on a preparative scale, where mechanical energy is used to buckle an intermediate monolayer into a more stable nanosheet. Detailed physical studies of the monolayer-compression mechanism revealed a simple preparative technique to produce nanosheets in 95% overall yield by cyclical monolayer compressions in a rotating closed vial. Compression of monolayers into stable, free-floating products may be a general and preparative approach to access 2D nanomaterials.
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Affiliation(s)
- Babak Sanii
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
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33
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Gamba P, Leonarduzzi G, Tamagno E, Guglielmotto M, Testa G, Sottero B, Gargiulo S, Biasi F, Mauro A, Viña J, Poli G. Interaction between 24-hydroxycholesterol, oxidative stress, and amyloid-β in amplifying neuronal damage in Alzheimer's disease: three partners in crime. Aging Cell 2011; 10:403-17. [PMID: 21272192 DOI: 10.1111/j.1474-9726.2011.00681.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
All three cholesterol oxidation products implicated thus far in the pathogenesis of Alzheimer's disease, 7β-hydroxycholesterol, 24-hydroxycholesterol, and 27-hydroxycholesterol, markedly enhance the binding of amyloid-beta (Aβ) to human differentiated neuronal cell lines (SK-N-BE and NT-2) by up-regulating net expression and synthesis of CD36 and β1-integrin receptors. However, only 24-hydroxycholesterol markedly potentiates the pro-apoptotic and pro-necrogenic effects of Aβ(1-42) peptide on these cells: 7β-hydroxycholesterol and 27-hydroxycholesterol, like unoxidized cholesterol, show no potentiating effect. This peculiar behavior of 24-hydroxycholesterol at physiologic concentrations (1 μm) depends on its strong enhancement of the intracellular generation of NADPH oxidase-dependent reactive oxygen species (ROS), mainly H(2) O(2) , and the consequent impairment of neuronal cell redox equilibrium, measured in terms of the GSSG/GSH ratio. Cell incubation with antioxidants quercetin or genistein prevents 24-hydroxycholesterol's pro-oxidant effect and potentiation of Aβ-induced necrosis and apoptosis. Thus, the presence of 24-hydroxycholesterol in the close vicinity of amyloid plaques appears to enhance the adhesion of large amounts of Aβ to the plasma membrane of neurons and then to amplify the neurotoxic action of Aβ by locally increasing ROS steady-state levels. This report further supports a primary involvement of altered brain cholesterol metabolism in the complex pathogenesis of Alzheimer's disease.
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Affiliation(s)
- Paola Gamba
- Department of Clinical and Biological Sciences, Faculty of Medicine San Luigi Gonzaga, University of Turin, Italy
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Ta HP, Berthelot K, Coulary-Salin B, Desbat B, Géan J, Servant L, Cullin C, Lecomte S. Comparative studies of nontoxic and toxic amyloids interacting with membrane models at the air-water interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:4797-4807. [PMID: 21405042 DOI: 10.1021/la103788r] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Many in vitro studies have pointed out the interaction between amyloids and membranes, and their potential involvement in amyloid toxicity. In a previous study, we generated a yeast toxic mutant (M8) of the harmless model amyloid protein HET-s((218-289)). In this study, we compared the self-assembling process of the nontoxic wild-type (WT) and toxic (M8) protein at the air-water interface and in interaction with various phospholipid monolayers (DOPE, DOPC, DOPI, DOPS and DOPG). We first demonstrate using ellipsometry measurements and polarization-modulated infrared reflection absorption spectroscopy (PMIRRAS) that the air-water interface promotes and modifies the assembly of WT since an amyloid-like film was instantaneously formed at the interface with an antiparallel β-sheet structuration instead of the parallel β-sheet commonly observed for amyloid fibers generated in solution. The toxic mutant (M8) behaves in a similar manner at the air-water interface or in bulk, with a fast self-assembling and an antiparallel β-sheet organization. The transmission electron microscopy (TEM) images established the fibrillous morphology of the protein films formed at the air-water interface. Second, we demonstrate for the first time that the main driving force between this particular fungus amyloid and membrane interaction is based on electrostatic interactions with negatively charged phospholipids (DOPG, DOPI, DOPS). Interestingly, the toxic mutant (M8) clearly induces perturbations of the negatively charged phospholipid monolayers, leading to a massive surface aggregation, whereas the nontoxic (WT) exhibits a slight effect on the membrane models. This study allows concluding that the toxicity of the M8 mutant could be due to its high propensity to interact with membranes.
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Affiliation(s)
- Ha Phuong Ta
- Chimie et Biologie des Membranes et Nano-objets, Université de Bordeaux-CNRS, 2 rue Robert Escarpit, 33607 Pessac, France
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Ye M, Zhang Y, Li H, Xie M, Hu J. Supramolecular Structures of Amyloid-Related Peptides in an Ambient Water Nanofilm. J Phys Chem B 2010; 114:15759-65. [PMID: 21077660 DOI: 10.1021/jp105501x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ming Ye
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China and Graduate School of the Chinese Academy of Sciences, Beijing 100049, China
| | - Yi Zhang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China and Graduate School of the Chinese Academy of Sciences, Beijing 100049, China
| | - Hai Li
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China and Graduate School of the Chinese Academy of Sciences, Beijing 100049, China
| | - Muyun Xie
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China and Graduate School of the Chinese Academy of Sciences, Beijing 100049, China
| | - Jun Hu
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China and Graduate School of the Chinese Academy of Sciences, Beijing 100049, China
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Lasagna-Reeves CA, Clos AL, Midoro-Hiriuti T, Goldblum RM, Jackson GR, Kayed R. Inhaled insulin forms toxic pulmonary amyloid aggregates. Endocrinology 2010; 151:4717-24. [PMID: 20685871 DOI: 10.1210/en.2010-0457] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
It is well known that interfaces, such as polar-nonpolar or liquid-air, play a key role in triggering protein aggregation in vitro, in particular the aggregation of peptides and proteins with the predisposition of misfolding and aggregation. Here we show that the interface present in the lungs predisposes the lungs to form aggregation of inhaled insulin. Insulin inhalers were introduced, and a large number of diabetic patients have used them. Although inhalers were safe and effective, decreases in pulmonary capacity have been reported in response to inhaled insulin. We hypothesize that the lung air-tissue interface provides a template for the aggregation of inhaled insulin. Our studies were designed to investigate the harmful potential that inhaled insulin has in pulmonary tissue in vivo, through an amyloid formation mechanism. Our data demonstrate that inhaled insulin rapidly forms amyloid in the lungs causing a significant reduction in pulmonary air flow. Our studies exemplify the importance that interfaces play in protein aggregation in vivo, illustrating the potential aggregation of inhaled proteins and the formation of amyloid deposits in the lungs. These insulin deposits resemble the amyloid structures implicated in protein misfolding disorders, such as Alzheimer's and Parkinson's diseases, and could as well be deleterious in nature.
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Affiliation(s)
- Cristian A Lasagna-Reeves
- George and Cynthia Mitchell Center for Neurodegenerative Diseases, Department of Neurology, University of Texas Medical Branch, 301 University Boulevard, Medical Research Building, Room 10.138C, Galveston, Texas 77555-1045, USA
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37
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Wang C, Shah N, Thakur G, Zhou F, Leblanc RM. Alpha-synuclein in alpha-helical conformation at air-water interface: implication of conformation and orientation changes during its accumulation/aggregation. Chem Commun (Camb) 2010; 46:6702-4. [PMID: 20714568 DOI: 10.1039/c0cc02098b] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Alpha-synuclein, a natively unstructured protein important in the neuropathology of Parkinson's disease, was found to form a Langmuir monolayer in an alpha-helical conformation with its helical axis parallel to the air-water interface. This study sheds light on the role of vesicles in neuronal cells in the accumulation/aggregation of alpha-synuclein.
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Affiliation(s)
- Chengshan Wang
- California State University, Los Angeles, 5151 State University Drive, Los Angeles, CA 90032, USA
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38
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Jiang D, Li X, Liu L, Yagnik GB, Zhou F. Reaction rates and mechanism of the ascorbic acid oxidation by molecular oxygen facilitated by Cu(II)-containing amyloid-beta complexes and aggregates. J Phys Chem B 2010; 114:4896-903. [PMID: 20302320 DOI: 10.1021/jp9095375] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A forefront of the research on Alzheimer's disease (AD) is the interaction of amyloid beta (Abeta) peptides with redox metal ions (e.g., Cu(II), Fe(III), and Fe(II)) and the biological relevance of the Abeta-metal complexes to neuronal cell loss and homeostasis of essential metals and other cellular species. This work is concerned with the kinetic and mechanistic studies of the ascorbic acid oxidation reaction by molecular oxygen that is facilitated by Cu(II) complexes with Abeta(1-16), Abeta(1-42), and aggregates of Abeta(1-42). The reaction rate was found to linearly increase with the concentrations of Abeta-Cu(II) and dissolved oxygen and be invariant with high ascorbic acid concentrations. The rate constants were measured to be 117.2 +/- 15.4 and 15.8 +/- 2.8 M(-1) s(-1) at low (<100 muM) and high AA concentrations, respectively. Unlike free Cu(II), in the presence of AA, Abeta-Cu(II) complexes facilitate the reduction of oxygen by producing H(2)O(2) as a major product. Such a conclusion is drawn on the basis that the reaction stoichiometry between AA and O(2) is 1:1 when the Abeta concentration is kept at a much greater value than that of Cu(II). A mechanism is proposed for the AA oxidation in which the oxidation states of the copper center in the Abeta complex alternates between 2+ and 1+. The catalytic activity of Cu(II) toward O(2) reduction was found to decrease in the order of free Cu(II) > Abeta(1-16)-Cu(II) > Abeta(1-42)-Cu(II) > Cu(II) complexed by the Abeta oligomer/fibril mixture > Cu(II) in Abeta fibrils. The finding that Cu(II) in oligomeric and fibrous Abeta aggregates possesses considerable activity toward H(2)O(2) generation is particularly significant, since in senile plaques of AD patients the coexisting copper and Abeta aggregates have been suggested to inflict oxidative stress through the production of reactive oxygen species (ROS). Although Cu(II) bound to oligomeric and fibrous Abeta aggregates is less effective than free Cu(II) and the monomeric Abeta-Cu(II) complex in producing ROS, in vivo the Cu(II)-containing Abeta oligomers and fibrils might be more biologically relevant given their stronger association with cell membranes and the closer proximity of ROS to cell membranes.
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Affiliation(s)
- Dianlu Jiang
- Department of Chemistry and Biochemistry, California State University, Los Angeles, Los Angeles, California 90032, USA
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39
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Zheng J, Yu X, Wang J, Yang JC, Wang Q. Molecular modeling of two distinct triangular oligomers in amyloid beta-protein. J Phys Chem B 2010; 114:463-70. [PMID: 20014755 DOI: 10.1021/jp907608s] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Amyloid-beta (Abeta) peptides exhibit many distinct structural morphology at the early aggregate stage, some of which are biological relevant to the pathogenesis of Alzheimer's disease (AD). Atomic-resolution structures of the early Abeta aggregates and their conformational changes in amyloid aggregation remain elusive. Here, we perform all-atom molecular modeling and dynamics simulations to obtain two stable triangular-like Abeta structures with the lowest packing energy, one corresponding to the Tycko's model (Paravastu, A.; Leapman, R.; Yau, W.; Tycko, R. Proc. Nat. Acad. Soc. U.S.A. 2008, 105, 18349-18354) (referred to C-WT model) and the other corresponding to computational model (N-WT model). Both models have the same 3-fold symmetry but distinct beta-sheet organizations in which three Abeta hexamers pack together via either C-terminal beta-strand residues or N-terminal beta-strand residues forming distinct hydrophobic cross section. Structural and energetic comparisons of two 3-fold Abeta oligomers, coupled with structural changes upon the mutations occurring at the interacting interfaces, reveal that although hydrophobic interactions are still dominant forces, electrostatic interactions are more favorable in the N-WT model due to the formation of more and stable intersheet salt bridges, while solvation energy is more favorable in the C-WT model due to more exposed hydrophilic residues to solvent. Both models display many common features similar to other amyloid oligomers and therefore are likely to be biologically relevant.
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Affiliation(s)
- Jie Zheng
- Department of Chemical and Biomolecular Engineering, University of Akron, Akron, Ohio 44325, USA.
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Wang Q, Zhao C, Zhao J, Wang J, Yang JC, Yu X, Zheng J. Comparative molecular dynamics study of Abeta adsorption on the self-assembled monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:3308-3316. [PMID: 19928820 DOI: 10.1021/la903070y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The adsorption and aggregation of the amyloid-beta (Abeta) peptides on the cell membrane plays a causal role in the pathogenesis of Alzheimer's disease. Here, we report all-atom molecular dynamics (MD) simulations to study the interactions of Abeta oligomer with self-assembled monolayers (SAMs) terminated with hydrophobic CH(3) and hydrophilic OH functional groups, with particular interests in how surface chemistry and Abeta orientation affect the adsorption behavior of Abeta. Simulation results show that the CH(3)-SAM has a stronger binding affinity to Abeta than the OH-SAM does, although both surfaces can induce Abeta adsorption. Regardless of the characteristics of the surface, the hydrophobic C-terminal region is more likely to be adsorbed on the SAMs, indicating a preferential orientation and interface for Abeta adsorption. Structural and energetic comparison among six Abeta-SAM systems further reveals that Abeta orientation, SAM surface hydrophobicity, and interfacial waters all determine Abeta adsorption behavior on the surface, highlighting the importance of hydrophobic interactions at the interface. This work may provide parallel insights into the interactions of Abeta with lipid bilayers.
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Affiliation(s)
- Qiuming Wang
- Department of Chemical and Biomolecular Engineering University of Akron, Akron, Ohio 44325, USA
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Tooke L, Duitch L, Measey TJ, Schweitzer-Stenner R. Kinetics of the self-aggregation and film formation of poly-L-proline at high temperatures explored by circular dichroism spectroscopy. Biopolymers 2009; 93:451-7. [DOI: 10.1002/bip.21361] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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42
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Role of small oligomers on the amyloidogenic aggregation free-energy landscape. J Mol Biol 2009; 395:134-54. [PMID: 19837085 DOI: 10.1016/j.jmb.2009.10.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 10/07/2009] [Accepted: 10/12/2009] [Indexed: 11/20/2022]
Abstract
We combine atomic-force-microscopy particle-size-distribution measurements with earlier measurements on 1-anilino-8-naphthalene sulfonate, thioflavin T, and dynamic light scattering to develop a quantitative kinetic model for the aggregation of beta-lactoglobulin into amyloid. We directly compare our simulations to the population distributions provided by dynamic light scattering and atomic force microscopy. We combine species in the simulation according to structural type for comparison with fluorescence fingerprint results. The kinetic model of amyloidogenesis leads to an aggregation free-energy landscape. We define the roles of and propose a classification scheme for different oligomeric species based on their location in the aggregation free-energy landscape. We relate the different types of oligomers to the amyloid cascade hypothesis and the toxic oligomer hypothesis for amyloid-related diseases. We discuss existing kinetic mechanisms in terms of the different types of oligomers. We provide a possible resolution to the toxic oligomer-amyloid coincidence.
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