Structural and functional aspects of membranes the involvement of lipid rafts in Alzheimer's disease pathogenesis : the interplay between protein oligomers and plasma membrane physicochemical features in determining cytotoxicity
Alzheimer's disease (AD) is a common form of dementia characterized by the formation of extracellular senile plaques composed of aggregated amyloid peptide (Aβ). The present studies provide evidence that: cell resistance to amyloid toxicity is related to lipid raft cholesterol content. Choleste...
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| Formato: | Libro electrónico |
| Idioma: | Inglés |
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Firenze :
Firenze University Press
2013.
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| Colección: | Premio Tesi di dottorato.
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| Materias: | |
| Ver en Biblioteca Universitat Ramon Llull: | https://discovery.url.edu/permalink/34CSUC_URL/1im36ta/alma991009746771506719 |
Tabla de Contenidos:
- Summary
- Introduction
- 1.1 Protein aggregation and amyloidoses
- 1.1.1 Mechanisms of amyloid fibril formation
- 1.1.2 Oligomer structural polymorphism: fibrillar and prefibrillar oligomers
- 1.1.3 Oligomer toxicity: common mechanism of pathogenesis
- 1.1.4 Amyloid formation is an inherent property of polypeptide chains: functional amyloid and disease unreleated amyloid
- 1.2 HypF-N: model protein of amyloid aggregation unrelated to disease
- 1.2.1 Function, structure and aggregation of HypF-N
- 1.2.2 HypF-N protofibrils interact with cell membranes originating a cytotoxic cascade
- 1.2.3 A causative link between the structure of HypF-N oligomers and their ability to cause cellular dysfunction
- 1.3 Alzheimer's disease
- 1.3.1 The Alzheimer phenotype
- 1.3.2 The elaborate processing of APP
- 1.3.3 The genetics of Alzheimer's disease
- 1.3.4 Peripheral cells as a tool to identify and test hypotheses on AD pathophysiology
- 1.3.5 Adult neurogenesis and stem cell technology for AD
- 1.4 Cholesterol and gangliosides in the central nervous system (CNS)
- 1.4.1 Brain cholesterol metabolism
- 1.4.2 Ganglioside metabolism
- 1.4.3 Lipid rafts
- 1.4.4 Role of cholesterol in AD
- 1.4.5 Role of gangliosides in AD
- 1.5 Aim of the study
- Materials & Methods
- 2.1 Materials
- 2.1.1 Chemicals
- 2.1.2 Fluorescent probes
- 2.1.3 Peptides and aggregation protocols
- 2.2 Cell cultures
- 2.3 Methods
- 2.3.1 Separation processes
- 2.3.2 Differentiation of human mesenchymal stromal cells
- 2.3.3 Modulation of membrane cholesterol levels
- 2.3.4 Modulation of membrane GM1 levels
- 2.3.5 Cholesterol content measurements
- 2.3.6 GM1 content measurements
- 2.3.7 Cell exposure to peptide aggregates
- 2.3.8 Analysis of aggregate interaction with the cells
- 2.3.9 Analysis of aggregate interaction with GM1
- 2.3.10 Analysis of aggregate internalisation
- 2.3.11 Analysis of membrane permeability
- 2.3.12 Analysis of cytosolic Ca2+ dyshomeostasis
- 2.3.13 Evaluation of ROS production
- 2.3.14 Analysis of lipid peroxidation
- 2.3.15 Cytotoxicity assay and cell death analysis: apoptotic and necrotic markers
- 2.3.16 Steady-state fluorescence anisotropy
- 2.3.17 Atomic force microscopy (AFM)
- 2.3.18 Measurements of the fluorescence intensities
- 2.3.19 Statistical analysis
- Results
- 3.1 Results I
- 3.1.1 A protective role for lipid raft cholesterol against amyloidinduced membrane damage in human neuroblastoma cells
- 3.1.2 Aß42 oligomer binding to the cell surface and its cytotoxic effect are modulated by membrane cholesterol content
- 3.1.3 Aß42 oligomers colocalize with lipid rafts
- 3.1.4 Isolation and characterization of DRMs
- 3.1.5 Effects of ADDLs on lipid raft structural order
- 3.1.6 AFM imaging of supported DRMs purified from cells exposed to ADDLs
- 3.2 Results II
- 3.2.1 Lipid rafts mediate amyloid-induced calcium dyshomeostasis and oxidative stress in Alzheimer's disease
- 3.2.2 Lipid rafts are primary interaction sites for Aß42 oligomers at the plasma membrane
- 3.2.3 Cholesterol and GM1 mediate Aß42 accumulation at the plasma membrane
- 3.2.4 Cholesterol and GM1 mediate Ca2+ dyshomeostasis and extensive membrane permeabilization induced by Aß42 oligomers
- 3.2.5 GM1 modulates lipid peroxidation and cytotoxicity induced by Aß42 oligomers
- 3.2.6 GM1 mediates Aß42-induced Ca2+ dyshomeostasis, lipid peroxidation and cytotoxicity in rat cortical neurons
- 3.3 Results III
- 3.3.1 Membrane lipid composition and its physicochemical properties define cell vulnerability to aberrant protein oligomers
- 3.3.2 Membrane cholesterol content modulates oligomer cytotoxicity
- 3.3.3 Membrane cholesterol modulates oligomer-induced alteration of intracellular Ca2+ homeostasis and ROS levels
- 3.3.4 Cholesterol levels modulate membrane permeability to the oligomers
- 3.3.5 Membrane GM1 affects the cytotoxic and permeabilizing effects of HypF-N oligomers
- 3.3.6 GM1, rather than cholesterol, plays a dominant role in oligomer cytotoxicity and membrane permeability
- 3.4 Results IV
- 3.4.1 Neuronal differentiation of human mesenchymal stromal cells increases their resistance to Aß42 aggregate toxicity
- 3.4.2 Neuronal differentiation of hMSCs results in reduced levels of membrane GM1
- 3.4.3 Neuronal differentiation of hMSCs reduces the interaction of Aß42 oligomers with the cell surface
- 3.4.4 Neuronal differentiation of hMSCs reduces Aß42 oligomerinduced intracellular Ca2+ dyshomeostasis and oxidative stress
- 3.4.5 Neuronal differentiation of hMSCs increases cell resistance to Aß42 aggregates Discussion
- 4.1 A protective role for lipid raft cholesterol against amyloid-induced membrane damage in human neuroblastoma cells
- 4.2 Lipid rafts mediate amyloid-induced calcium dyshomeostasis and membrane permeabilization in Alzheimer's fibroblasts
- 4.3 Membrane lipid composition and its physicochemical properties define cell vulnerability to aberrant protein oligomers
- 4.4 Neuronal differentiation of human mesenchymal stromal cells increases their resistance to Aß42 aggregate toxicity
- 4.5 Concluding remarks
- Abbreviations
- References.
