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The effect of amyloid beta on viability of selected neuropathogens: challenging the infectious hypothesis of Alzheimer disease
Vosála, Ondřej ; Macháček, Tomáš (advisor) ; Černý, Jan (referee)
Alzheimer's disease is the leading cause of dementia worldwide, affecting millions of individuals. Researchers have identified amyloid beta (A ) as the primary agent responsible for neuropathogenicity, but the factors triggering its overproduction remain uncertain. An relatively new theory, known as the infectious hypothesis, sheds light on this phenomenon by associating the excess production of A with its potential role as an antimicrobial peptide-an element of the innate immune response against neuroinfections. This hypothesis posits a transition from acute physiological overproduction during neuroinfection to a chronically dysregulated and pathological process targeting both pathogens and neural tissue. So far, experimental evidence supporting this theory has been primarily obtained through studies involving viruses or bacteria. Aim of this study was to investigate the role of multicellular pathogens in stimulating A overproduction and, on the other hand, A role in elimination of such infections. Toxocara canis was chosen as a main model of neuropathogenic parasite. Although successful infections were achieved in BALB/c mice, there was no observable increase in A production even after 16 weeks of infection. To further challenge the survivability of Toxocara larvae in increased A concentration in...
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Sample preparation for analyzing oligomeric forms of amyloid beta by mass spectrometry
Mrkvičková, Simona ; Cvačka, Josef (advisor) ; Kozlík, Petr (referee)
Alzheimer's disease is the most widespread chronic and progressive neurodegenerative disease. The main problem of the disease is the reduction and damage of nerve cells. This leads to loss of brain mass and memory impairment. The disease mainly affects the elderly, for whom it is the most common cause of dementia. Around 50 million people suffer from this disease worldwide, and the number is growing. Alzheimer's disease thus represents a serious public health problem. The pathogenesis of this disease is controlled by the production and deposition of amyloid beta peptide. This peptide tends to aggregate. Its lower oligomeric forms are water-soluble and have a toxic effect on nerve cells. Amyloid beta oligomers therefore represent a possible target for the diagnosis of Alzheimer's disease. Oligomeric forms of beta amyloids have a non-covalent character, which can negatively affect their stability during analyzes in model and biological samples. In this bachelor thesis, suitable conditions for the preparation of model amyloid beta samples were sought. It was observed how the distribution of oligomeric forms changes under the influence of solvents, salts and other additives. The effect of pH on the incubation of amyloid beta in ammonium acetate and water was also investigated. Finally, a method for the...
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Use of separation and mass spectrometric techniques in the diagnosis of Alzheimer's disease
Lebertová, Lucie ; Cvačka, Josef (advisor) ; Kozlík, Petr (referee)
This thesis focuses on the preparation of covalently cross-linked oligomeric forms of amyloid beta and their analysis by SDS-PAGE and MALDI-TOF. The covalently cross-linked oligomeric forms of Aβ(1-42) were formed by chemical and enzymatic reactions. The chains of amyloid beta are crossed over the amino acid residue of tyrosine to form a covalent bond. Such covalent cross-linking stabilizes the oligomeric structure, which allows for improved analysis of amyloid beta oligomers. The development of methods for the detection and quantification of amyloid beta oligomers may be of considerable benefit for the diagnosis of Alzheimer's disease, as it is the oligomeric forms of amyloid beta that are most strongly associated with Alzheimer's disease pathology. In the theoretical part, Alzheimer's disease is described with the above-mentioned problems in early diagnosis and therapy. In addition, background information on amyloid beta is given, and analytical methods for the separation and detection of amyloid beta used in research are described. The experimental part deals with the optimization of analytical methods MALDI-TOF and SDS-PAGE. In the MALDI-TOF, 2,5-dihydroxybenzoic acid and sinapic acid matrices were selected as suitable matrices for the determination of Aβ(1-42). The most suitable method of...
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Influence of nanoparticles and polymers on the amyloid fibril formation
Holubová, Monika ; Štěpánek, Petr (advisor) ; Štěpánek, Miroslav (referee) ; Nardin, Corrine (referee)
The thesis deals with the testing of amyloidogenicity of various carbon nanoparticles and polymers. The first part of the thesis provides the theoretical background of amyloidoses, a group of diseases in which proteins are stored in the insoluble form of amyloid. In addition, the theoretical part also deals with a general overview of nanomaterials and the most important methods. Several types of nanomaterials were tested within the thesis, so the part Results and Discussion was divided into two subchapters: 1) Carbon nanospecies and amyloid fibril formation, and 2) Polysaccharides, glycogen modifications and amyloid fibril formation. The first subchapter concerns the testing of four types of carbon nanoparticles (single-walled carbon nanotubes (SWNT), fullerenes (C60), carbon quantum dots (CDs) and nanodiamonds (NDs)). These materials were tested on a model system hen egg white lysozyme (HEWL). Using fluorescence measurements and transmission electron microscopy (TEM), the nanoparticles were ranked from the most to the least amyloidogenic as follows: NDs> control> C60> CDs> SWNT. The second subchapter deals with the effect of selected polysaccharides (glycogen (GG), mannan (MAN), phytoglycogen (PG)) and modified GG on amyloid fibril formation. These materials were tested on the HEWL model system,...
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The importance of lipid composition of membranes for the development of Alzheimer's disease
Novotná, Natálie ; Rudajev, Vladimír (advisor) ; Hanousková, Barbora (referee)
Lipids are an essential components of cell membranes and their homeostasis plays an important role in the development of Alzheimer's disease. The aggregation and neurotoxic effects of amyloid β, mainly Aβ42, on the neural cell membrane are crucial for pathological changes in the brain tissue which leads to its degeneration and loss of cognitive functions. The complex relationship between amyloid β and lipids is also supported by fact that membrane lipids do not only support the amyloid binding to the membrane, but also they regulate the splicing of the amyloid precursor protein, therefore the biosynthesis of β amyloid. The most important binding partners of Aβ42 include gangliosides, especially the ganglioside GM1, but also sphingomyelin and cholesterol. In contrast, glycerophospholipids primarily affect the process of the protein production.
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Influence of nanoparticles and polymers on the amyloid fibril formation
Holubová, Monika ; Štěpánek, Petr (advisor) ; Štěpánek, Miroslav (referee) ; Nardin, Corrine (referee)
The thesis deals with the testing of amyloidogenicity of various carbon nanoparticles and polymers. The first part of the thesis provides the theoretical background of amyloidoses, a group of diseases in which proteins are stored in the insoluble form of amyloid. In addition, the theoretical part also deals with a general overview of nanomaterials and the most important methods. Several types of nanomaterials were tested within the thesis, so the part Results and Discussion was divided into two subchapters: 1) Carbon nanospecies and amyloid fibril formation, and 2) Polysaccharides, glycogen modifications and amyloid fibril formation. The first subchapter concerns the testing of four types of carbon nanoparticles (single-walled carbon nanotubes (SWNT), fullerenes (C60), carbon quantum dots (CDs) and nanodiamonds (NDs)). These materials were tested on a model system hen egg white lysozyme (HEWL). Using fluorescence measurements and transmission electron microscopy (TEM), the nanoparticles were ranked from the most to the least amyloidogenic as follows: NDs> control> C60> CDs> SWNT. The second subchapter deals with the effect of selected polysaccharides (glycogen (GG), mannan (MAN), phytoglycogen (PG)) and modified GG on amyloid fibril formation. These materials were tested on the HEWL model system,...
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Geny a Alzheimerova choroba, možnosti diagnostiky
KOUDELKOVÁ, Kateřina
The aim of this work is to summarize findings about Alzheimer´s disease, which is the most common neurodegenerative disorder, its pathophysiology, epidemiology, risk factors, treatment options and genetics of disease. Further aim was to describe diagnostic options that are important to confirm the diagnosis of Alzheimer´s disease and to timely iniciation of treatment.
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Muscarinic acetylcholine transmission and Alzheimer's disease
Janíčková, Helena ; Doležal, Vladimír (advisor) ; Blahoš, Jaroslav (referee) ; Rokyta, Richard (referee)
Impairment of the cholinergic neurotransmission system is regularly detected in animal models of Alzheimer's disease as well as in human patients suffering from this serious disease. Moreover, there is increasing amount of evidence suggesting that activation of individual mAChR subtypes specifically influences the cleavage of APP, the precursor for β-amyloid. APP can be processed in an amyloidogenic or non-amyloidogenic pathway and a relative abundance of these patways contributes to establishing the final concentration of neurotoxic β-amyloid in the brain. In this work, I have studied the acute and chronic effects of A β1-42 on binding and functional characteristics of mAChR. I have demonstrated that Aβ1-42 present in cell culture expressing the individual subtypes of mAChR negatively and specifically influences the function of the M1 mAChR subtype. I have also detected a decline in muscarinic receptor-mediated signal transduction in brain tissue of young adult APPswe/PS1dE9 mice, a commonly used animal model of Alzheimer's disease. Demonstration of the impairment of muscarinic transmissin in transgenic mice by soluble β-amyloid that occurs earlier than amyloid pathology and behavioral deficit, and its imitation by soluble Aβ1-42 in vitro lend strong support to the notion of the early involvement...
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