Monitoring self-assembly of Aβ40 using Differential Scanning Calorimetry
(2024) KEMK10 20241Department of Chemistry
- Abstract
- The aggregation of amyloid β in the brain is considered to be the main cause of the currently incurable Alzheimer’s disease. Research investigating fibrils is being conducted continuously. Despite this, there is an incredibly large knowledge gap in what we know about the aggregation process. This study aims to investigate the temperature influence on the Aβ40 aggregation process using differential scanning calorimetry and to probe the thermostability of the Aβ40 fibrils using Fluorescence assays. Using differential scanning calorimetry, qualitative parameters such as lag time and elongation time can be evaluated at different temperatures. It was established that the lag time became shorter and that the reaction occurred faster at the... (More)
- The aggregation of amyloid β in the brain is considered to be the main cause of the currently incurable Alzheimer’s disease. Research investigating fibrils is being conducted continuously. Despite this, there is an incredibly large knowledge gap in what we know about the aggregation process. This study aims to investigate the temperature influence on the Aβ40 aggregation process using differential scanning calorimetry and to probe the thermostability of the Aβ40 fibrils using Fluorescence assays. Using differential scanning calorimetry, qualitative parameters such as lag time and elongation time can be evaluated at different temperatures. It was established that the lag time became shorter and that the reaction occurred faster at the higher temperatures, despite the reaction being exothermal. The total change in enthalpy was quantitatively determined at each temperature. In the magnitude of MJ/mol, the enthalpy change decreased from 25 oC to 37 oC. No difference in enthalpy could be observed between 37 oC and 45 oC. In conclusion, temperature has a strong impact on the Aβ40 aggregation process. Whether it is because of the temperature itself, or due to the equilibrium between monomer and fibril affecting the participating number of monomers, requires further investigation. With fluorescence assay, Aβ40 fibrils were investigated at 8 oC to examine the thermostability of the fibrils and to detect reversibility. The fluorescence assay at 8 oC showed no difference in ThT signal during this investigation. Instead, the fibril concentration was constant, and the reverse reaction could not be observed. Hence, the amyloid fibrils that were formed in this experiment are as stable at 8 oC as at 37 oC. Thus, the reverse reaction is not triggered by lowering the temperature within the time frame of the current experiment. (Less)
- Popular Abstract (Swedish)
- Alzheimers sjukdom är den vanligaste typen av demenssjukdom. Den har drabbat miljontals människor, men ännu finns det inget sätt att bota sjukdomen. Huvudorsaken till Alzheimers sjukdom tros vara ansamlingar i hjärnan av peptiden amyloid β som självmant kan interagera med andra peptider av sin sort och bilda mycket stabila och organiserade amyloida fibriller. En mängd monomera amyloida β peptider med olika längd bildas när det kroppsliga proteinet amyloid precursor protein klyvs av β- och γ-secretaser. De två vanligaste isoformerna som bildas är Aβ40 och Aβ42, bestående av 40 och 42 aminosyror vardera och dessa anses vara de mest bidragande formerna till Alzheimers sjukdom. Detta understryker relevansen för att undersöka och bilda... (More)
- Alzheimers sjukdom är den vanligaste typen av demenssjukdom. Den har drabbat miljontals människor, men ännu finns det inget sätt att bota sjukdomen. Huvudorsaken till Alzheimers sjukdom tros vara ansamlingar i hjärnan av peptiden amyloid β som självmant kan interagera med andra peptider av sin sort och bilda mycket stabila och organiserade amyloida fibriller. En mängd monomera amyloida β peptider med olika längd bildas när det kroppsliga proteinet amyloid precursor protein klyvs av β- och γ-secretaser. De två vanligaste isoformerna som bildas är Aβ40 och Aβ42, bestående av 40 och 42 aminosyror vardera och dessa anses vara de mest bidragande formerna till Alzheimers sjukdom. Detta understryker relevansen för att undersöka och bilda förståelse för processen där amyloida fibriller bildas.
Med kalorimetri undersöktes reaktionen där Aβ40 monomerer associeras och bildar amyloida fibriller. Genom att isotermt mäta den värme som den exoterma reaktionen avger vid olika temperaturer (20 oC, 30 oC, 37 oC och 45 oC), kunde slutsatser dras om hur temperatur påverkar reaktionens hastighet, lagfas, samt den entalpiska ändringen. Det observerades att vid de högre temperaturerna var lagfasen kortare. Bildandet av fibrillerna skedde snabbare och den entalpiska ändringen var också störst vid dessa temperaturer.
I detta arbete undersöktes reversibiliteten för reaktionen vid kylskåpstemperatur. Det studerades huruvida de bildade fibrillerna kunde återgå till den monomera formen, samt ifall fibrillerna var stabila vid denna temperatur. ThT användes vid fluorescensmätningar då den endast kan ge upphov till emission när den binder till fibriller. Fluorescensmätningar vid 8 oC utfördes på redan bildade fibriller och varken en ökning eller minskning av ThT signal kunde observeras. Detta indikerade att det inte skett någon förändring i antalet, samt Aβ40 fibrillerna som bildats i detta experiment konstaterades vara mycket stabila vid kylskåpstemperatur. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9162119
- author
- Wester, Frida LU
- supervisor
-
- Sara Linse LU
- Emil Axell LU
- organization
- course
- KEMK10 20241
- year
- 2024
- type
- M2 - Bachelor Degree
- subject
- keywords
- Amyloid β 40, differential scanning calorimetry, fibril formation, biochemistry
- language
- English
- id
- 9162119
- date added to LUP
- 2024-06-14 14:07:37
- date last changed
- 2024-06-14 14:07:37
@misc{9162119,
abstract = {{The aggregation of amyloid β in the brain is considered to be the main cause of the currently incurable Alzheimer’s disease. Research investigating fibrils is being conducted continuously. Despite this, there is an incredibly large knowledge gap in what we know about the aggregation process. This study aims to investigate the temperature influence on the Aβ40 aggregation process using differential scanning calorimetry and to probe the thermostability of the Aβ40 fibrils using Fluorescence assays. Using differential scanning calorimetry, qualitative parameters such as lag time and elongation time can be evaluated at different temperatures. It was established that the lag time became shorter and that the reaction occurred faster at the higher temperatures, despite the reaction being exothermal. The total change in enthalpy was quantitatively determined at each temperature. In the magnitude of MJ/mol, the enthalpy change decreased from 25 oC to 37 oC. No difference in enthalpy could be observed between 37 oC and 45 oC. In conclusion, temperature has a strong impact on the Aβ40 aggregation process. Whether it is because of the temperature itself, or due to the equilibrium between monomer and fibril affecting the participating number of monomers, requires further investigation. With fluorescence assay, Aβ40 fibrils were investigated at 8 oC to examine the thermostability of the fibrils and to detect reversibility. The fluorescence assay at 8 oC showed no difference in ThT signal during this investigation. Instead, the fibril concentration was constant, and the reverse reaction could not be observed. Hence, the amyloid fibrils that were formed in this experiment are as stable at 8 oC as at 37 oC. Thus, the reverse reaction is not triggered by lowering the temperature within the time frame of the current experiment.}},
author = {{Wester, Frida}},
language = {{eng}},
note = {{Student Paper}},
title = {{Monitoring self-assembly of Aβ40 using Differential Scanning Calorimetry}},
year = {{2024}},
}