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Project title
Understanding the relationship between Parkinson’s disease and lysosomal storage diseases using state-of-the-art lipid pathway flux analysis
Supervisors names
Wendy Heywood
Jenny Hallqvist
Background:
Most cases of Parkinson’s disease (PD) are sporadic and associated with no known genetic mutations. Therefore we do not know why the majority of people develop PD. The lysosomal enzyme Glucocerebrosidase (GBA) catalyses one of the last steps of the glycosphingolipid degradation pathway, the removal of a single glucose from glucosylceramide to create ceramide. Mutations in the GBA gene result in the lysosomal storage disorder Gaucher disease but intriguingly, heterozygote mutation carriers have a significant risk for developing Parkinson’s disease [1]. This association may be crucial if we are to understand sporadic PD in the population.
Research from our laboratory shows that deficient activity of GBA disrupts not just lysosomal but also extra-lysosomal lipid metabolism on iPSC derived neurons. This ultimately appears to affect cellular energy metabolism. GBA is thought to have additional functions other than GSL degradation and can act as a transglucosidase removing glucose from glucosylceramide to cholesterol l[2]. Unpublished data from our group has shown glucosylated cholesterol is increased in GBA heterozygote neuronal cells and in the brain tissue of Parkinson’s disease patients. This indicates cholesterol metabolism has a so far unknown role in the pathogenesis of GBA deficiency.
Aims/Objectives:
The goal of this project is to understand the effect of GBA dysfunction on the flux of lipids related to its this pathway and its downstream effects on all major lipid pathways present in the brain.
Methods:
The project will involve using non-radioactive, stable isotope lipid (SIL) tracers, in a pulse and chase strategy, and using cutting-edge oOmic technology to monitor the metabolism and catabolism of these lipids in neuronal cell models. The breakdown and recycling of components of the SIL tracers will be measured using untargeted lipid profiling and targeted mass spectrometry. Lipid data will be analysed and computational modelling will be used to create a ‘lipid flux model’ of glucosylceramide catabolism and anabolism in different biological contexts such as moderated GBA activity using inhibitors, cellular stress and dietary cholesterol levels. Understanding the lipid flux of GBA will provide a unique understanding of this complex pathway that can be a valuable resource for drug targeting. This project is a unique opportunity for a student to obtain experience in lipid biochemistry, state-of-the-art omic technology and bioinformatics.
Timeline in Months
- 0-6 Training in cell culture and mass spectrometry methods
- 6-9 Creation of methods and targeted panels of glucosylceramide related lipids and phospholipids
- 9-12 Chemical synthesis of SIL glucosylceramide and feasibility checking on cell lines
- 12-18 Cell experiments on treated lines and cell lines from GBA mutants
- 18-22 Data analysis and lipid flux modelling
- 24-30 Functional confirmation and lipid pathway manipulation with drugs to determine their effect on the GBA lipid pathway flux
- 30-36 Thesis writing
References
- Chatterjee D, Krainc D. Mechanisms of Glucocerebrosidase Dysfunction in Parkinson's Disease. J Mol Biol. 2023 Jun 15;435(12):168023.
- Marques AR, .., Aerts JM et al. Glucosylated cholesterol in mammalian cells and tissues: formation and degradation by multiple cellular β-glucosidases. J Lipid Res. 2016 Mar;57(3):451-63.
Contact
Dr Wendy Heywood wendy.heywood@ucl.ac.uk