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Effect of Parkinson’s disease-related alpha-synuclein abnormalities on the maturation of distinct iPSC-derived neuronal populations 10.17863/CAM.13638 Santivanez Perez, Jessica Andrea Spillantini, Maria Grazia 0000000285447332 Paulsen, Ole 0000000222585455 Parkinson’s disease (PD) is the second most common age-related neurodegenerative condition. It is neuropathologically characterised by the presence of Lewy pathology and the degeneration of the midbrain dopaminergic neurons from the substantia nigra pars compacta. Lewy pathology mainly consists of filamentous aggregated alpha-synuclein and familial forms of PD can be caused by genetic alternations in the SNCA gene encoding alpha-synuclein. Alpha-synuclein is primarily localised to neuronal presynaptic terminals and has been implicated in the maintenance of synaptic function. Studies have proposed that it regulates the docking, fusion, clustering and trafficking of neurotransmitter-loaded presynaptic vesicles. Nowadays, it is possible to model PD in vitro by obtaining adult somatic cells from patients, reprogramming them into induced pluripotent stem cells (iPSCs), and differentiating iPSCs into neurons. For this project, iPSCs derived from two PD patients, one harbouring the A53T SNCA mutation, the other a SNCA triplication, and three healthy individuals, were employed. In the initial stage, I optimised a neuronal differentiation protocol originally developed for human embryonic stem cells to produce neurons belonging to two distinct brain regions affected in PD, the forebrain and midbrain, from the available human iPSC lines. Next, I assessed the maturation of the generated neurons over time using protein expression and electrophysiological techniques. Finally, I examined PD-related phenotypes such as alpha-synuclein aggregation and release, susceptibility to cell death, and the redistribution of presynaptic proteins. All the iPSC lines used gave rise to forebrain and midbrain neuronal cultures. Maturation was similar across lines, as no consistent differences were observed in the changes of the expression of 4 repeat tau isoforms, presynaptic protein levels or electrophysiological properties over time. However, the emergence of astrocytes varied between cultures derived from distinct iPSC lines. No robust differences in alpha-synuclein release and susceptibility to cell death were detected between patient- and control-derived neurons. Apart from the presence of larger alpha-synuclein-positive puncta in patient-derived neurons, no other signs of alpha-synuclein aggregation were detected. Despite this, midbrain patient-derived neurons with a SNCA triplication exhibited a significant redistribution of presynaptic protein VAMP-2/synaptobrevin-2, which interacts with alpha-synuclein, relative to controls. University of Cambridge 2017-10-03 Thesis Doctoral Doctor of Philosophy (PhD) en Gates Cambridge Selwyn College https://www.repository.cam.ac.uk/handle/1810/267708 https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/d2386b1f-a41a-4ec8-bfc4-c0df9b036055/download d816b64189e09d5a55e0cffb357c7b32 https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/c83ef11e-2a3c-4ab2-937f-f26f7f0c7898/download 87eda9de84448d1f82354d60eee3eb5f https://www.rioxx.net/licenses/all-rights-reserved/ Alpha-synuclein Parkinson's Disease iPSCs Neurodegeneration