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Effects of Charged Cholesterol Derivatives on Aβ40 Amyloid Formation
Title
Effects of Charged Cholesterol Derivatives on Aβ40 Amyloid Formation.
Creator
Elbassal, Esmail A., Liu, Haiyang, Morris, Clifford, Wojcikiewicz, Ewa P., Du, Deguo
Date Issued
2016-01-14
PURL
http://purl.flvc.org/fau/flvc_fau_islandoraimporter_10.1021_acs.jpcb.5b09557_1648064189
Format
Document (PDF)
Effects of small molecule modulators and Phospholipid Liposomes on βeta-amyloid (1-40) Amyloidogenesis
Title
Effects of small molecule modulators and Phospholipid Liposomes on βeta-amyloid (1-40) Amyloidogenesis.
Creator
Morris, Clifford, Du, Deguo, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description
Beta-Amyloid (1-40) (Aβ40) is an aggregation prone protein, which undergoes a nucleation-dependent aggregation process causing the pathological neurodegeneration by amyloid plaque formation implicated in Alzheimer’s disease. In this thesis, we investigated the effects of small molecule modulators extracted from the marine invertebrate Pseudopterogorgia elisabethae on the Aβ40 amyloidogenic process using in- vitro ThT fluorescence assay and atomic force microscopy. We also investigated the...
Show moreBeta-Amyloid (1-40) (Aβ40) is an aggregation prone protein, which undergoes a nucleation-dependent aggregation process causing the pathological neurodegeneration by amyloid plaque formation implicated in Alzheimer’s disease. In this thesis, we investigated the effects of small molecule modulators extracted from the marine invertebrate Pseudopterogorgia elisabethae on the Aβ40 amyloidogenic process using in- vitro ThT fluorescence assay and atomic force microscopy. We also investigated the effects of neutral and anionic phospholipid liposomes on Aβ40 aggregation. Our results show that a marine natural product Pseudopterosin-A and its derivatives can suppress and modulate the Aβ40 aggregation process. Furthermore, our results demonstrate that a neutral phospholipid liposome inhibits Aβ40 fibril formation, whereas the anionic liposomes promote it.
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Date Issued
2015
PURL
http://purl.flvc.org/fau/fd/FA00004453, http://purl.flvc.org/fau/fd/FA00004453
Subject Headings
Aggregation (Chemistry), Alzheimer's disease -- Pathogenesis, Alzheimer's disease -- Research, Amyloid beta protein, Molecular biology, Molecular dynamics, Prions, Proteins -- Metabolism -- Disorders
Format
Document (PDF)
Role of the N-Terminal Hydrophilic Region of Amyloid Beta Peptide in Amyloidogenesis, Membrane Interaction and Toxicity Associated with Alzheimer’s Disease
Title
Role of the N-Terminal Hydrophilic Region of Amyloid Beta Peptide in Amyloidogenesis, Membrane Interaction and Toxicity Associated with Alzheimer’s Disease.
Creator
Morris, Clifford M., Du, Deguo, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description
Alzheimer’s disease (AD) is a deleterious neurodegenerative disease caused in major part by the aberrant processing and accumulation of amyloid beta peptides. In this dissertation, we systematically investigated the role of N-terminal region (NTR) residues of amyloid (1-40) (Aβ40) peptide in amyloidogenesis, lipid bilayer membrane interaction and damage, as well as neurotoxicity. Herein, we investigated the role of NTR residues on the aggregation and amyloid fibril formation process, to gain...
Show moreAlzheimer’s disease (AD) is a deleterious neurodegenerative disease caused in major part by the aberrant processing and accumulation of amyloid beta peptides. In this dissertation, we systematically investigated the role of N-terminal region (NTR) residues of amyloid (1-40) (Aβ40) peptide in amyloidogenesis, lipid bilayer membrane interaction and damage, as well as neurotoxicity. Herein, we investigated the role of NTR residues on the aggregation and amyloid fibril formation process, to gain understanding on the electrostatic and hydrophobic constituents of the mechanism. This was achieved by substituting specific charged residues located in the NTR of Aβ40 and investigating their effects through a variety of techniques. We also investigated the role of NTR charged residues in their interaction with supported phospholipid bilayer membranes through the use of Quartz Crystal Microbalance with Dissipation (QCM-D) monitoring to gain insight on the mechanistic details of the interaction. To further understand the implications of substituting charged NTR residues on membrane interaction, pore formation and damage, we utilized a carboxyfluorescein dye leakage assay to quantify the membrane damage caused by Aβ40 and the NTR mutants. We also performed neurotoxicity assay with SH-SY5Y neuroblastoma cells to shed light on the effects of NTR substitutions on cellular toxicity. Finally, we synthesized a polymer, trimethyl chitosan (TMC), and utilized it as a polyelectrolyte monitor of electrostatic interactions occurring between TMC and the NTR of Aβ40. Our results demonstrate that the NTR charged residues of Aβ40 contribute significantly to the aggregation process, amyloidogenesis, and phospholipid membrane interaction and perturbation by means of electrostatic, thermodynamic and hydrophobic forces.
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Date Issued
2019
PURL
http://purl.flvc.org/fau/fd/FA00013246
Subject Headings
Alzheimer's disease, Amyloid beta-Peptides, Amyloid
Format
Document (PDF)
Gold Nanoparticles as a Probe for Amyloid-β Oligomer and Amyloid Formation
Title
Gold Nanoparticles as a Probe for Amyloid-β Oligomer and Amyloid Formation.
Creator
Esmail A. Elbassal, Clifford Morris, Thomas W. Kent, Thomas W. Kent, Bimlesh Ojha, Ewa P. Wojcikiewicz, Deguo Du
Abstract/Description
The process of amyloid-β (Aβ) amyloid formation is pathologically linked to Alzheimer’s disease (AD). The identification of Aβ amyloids and intermediates that are crucial players in the pathology of AD is critical for exploring the underlying mechanism of Aβ aggregation and the diagnosis of the disease. Herein, we performed a gold nanoparticle (AuNP)-based study to detect the formation of Aβ amyloid fibrils and oligomers. Our results demonstrate that the intensity of the surface plasmon...
Show moreThe process of amyloid-β (Aβ) amyloid formation is pathologically linked to Alzheimer’s disease (AD). The identification of Aβ amyloids and intermediates that are crucial players in the pathology of AD is critical for exploring the underlying mechanism of Aβ aggregation and the diagnosis of the disease. Herein, we performed a gold nanoparticle (AuNP)-based study to detect the formation of Aβ amyloid fibrils and oligomers. Our results demonstrate that the intensity of the surface plasmon resonance (SPR) absorption band of the AuNPs is sensitive to the quantity of Aβ40 amyloids. This allows the SPR assay to be used for detection and semi-quantification of Aβ40 amyloids, and characterization of the kinetics of Aβ amyloid formation. Furthermore, our study demonstrates that the SPR band intensity of the AuNPs is sensitive to the presence of oligomers of both Aβ40 and an Aβ40 mutant, which forms more stable oligomers. The kinetics of the stable oligomer formation of the Aβ40 mutant can also be monitored following the SPR band intensity change of AuNPs. Our results indicate that this nanoparticle based method can be used for mechanistic studies of early protein self-assembly and fibrillogenesis.
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Date Issued
2017
PURL
http://purl.flvc.org/fau/fd/FAUIR000499
Format
Document (PDF)