Alzheimer's disease (AD) is a devastating neurodegenerative disease affecting millions of people worldwide and costing hundreds of billions of dollars each year1. Only a handful of drugs exist that treat the disease symptomatically2 and no drug has a strong effect on disease progression3–5. Two major hallmarks of AD are the aggregation of the proteins amyloid beta (Aβ) into plaques and hyperphosphorylated tau into neurofibrillary tangles (NFT). To date, despite major efforts there is no cure.
In my PhD project I investigate the aggregation of tangles and plaques on an ultrastructural level directly in the post-mortem human brains of AD patients, which is still poorly understood (see Figure below). For this purpose, I use correlative light and electron microscopy (CLEM), which allows me to identify different aggregates using fluorescence microscopy followed by imaging with electron microscopy (EM) allowing us to get high resolution information6.
Interested master students could help me with the following subprojects:
1) Staging of tau tangles on an ultrastructural level in the human brain: Broadly, NFTs are characterized into pre-tangles, mature tangles and ghost tangles7. We will elucidate how tangles mature based on presence/absence of fibrils; number of fibrils; interaction with cellular organelles and overall ultrastructural features of affected neurons. This characterization will further serve as a benchmark for animal and in vitro models.
2) Optimization of a cryo-CLEM pipeline: In this large project a student would optimize parts of the pipeline to investigate neuropathological aggregates directly in the human brain. This includes high pressure freezing, fluorescence microscopy under cryo-conditions, cryo focused ion beam scanning electron microscopy, cryo electron tomography and image processing.
3) Volume EM of tau tangles: Very little is known about the 2D ultrastructure of the different tau tangle stages and even less about the 3D ultrastructural architecture. Using SBF-SEM we want to investigate neuronal damage and fibril distribution of whole tangles. Image processing is a large part of this project.
A student would learn different light microscopy techniques, immunohistochemistry, fluorescence staining, laser capture microdissection, resin embedding and heavy metal staining, cutting ultrathin sections (60 nm thin!) and EM. The duration of these projects is a semester or more and the results will be used for publication if possible. The project can be adjusted according to the student’s interests.
References
1. Wimo, A. & Prince, M. World Alzheimer Report 2010 – The Global Economic Impact of Dementia. Alzheimer’s Disease International. London 96 (2010).
2. Breijyeh, Z. & Karaman, R. Comprehensive Review on Alzheimer ’ s Disease : Molecules 25, 5789 (2020).
3. FDA’s Decision to Approve New Treatment for Alzheimer’s Disease | FDA. www.fda.gov/drugs/news-events-human-drugs/fdas-decision-approve-new-treatment-alzheimers-disease.
4. Lilly’s Donanemab Significantly Slowed Cognitive and Functional Decline in Phase 3 Study of Early Alzheimer’s Disease | Eli Lilly and Company. investor.lilly.com/news-releases/news-release-details/lillys-donanemab-significantly-slowed-cognitive-and-functional.
5. Qiao, Y., Chi, Y., Zhang, Q. & Ma, Y. Safety and efficacy of lecanemab for Alzheimer’s disease: a systematic review and meta-analysis of randomized clinical trials. Front Aging Neurosci 15, (2023).
6. Shahmoradian, S. H. et al. Lewy pathology in Parkinson’s disease consists of crowded organelles and lipid membranes. Nature Neuroscience 22, 1099–1109 (2019).
7. Moloney, C. M., Lowe, V. J. & Murray, M. E. Visualization of neurofibrillary tangle maturity in Alzheimer’s disease: A clinicopathologic perspective for biomarker research. Alzheimer’s & Dementia 17, 1554–1574 (2021).
