Date of Award

2016

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Neuroscience

Abstract

Misfolded, toxic forms of amyloid alpha synuclein (α-syn) have been implicated in Parkinson’s disease (PD) pathology and have been shown to spread throughout the brain in a prion-like manner, explaining the progressive loss of neurons in PD. The mechanisms of spread and cell death are unknown, however, evidence from previous studies suggests that neurons may undergo apoptosis due to the uptake of exogenous α-syn aggregate through the endocytic pathway and subsequent lysosomal rupture.

This study aimed to corroborate previous evidence of α-syn induced lysosomal rupture and investigate the cellular repercussions of rupture with respect to cell death and α-syn transfer. We hypothesized that α-syn aggregates can compromise the function of lysosomes, leading to the release of lysosomal contents. To test this, we immunofluorescently labeled an abundant lysosomal protease, cathepsin B, and analyzed the level of dispersion upon treatment with α-syn aggregates. Further, we hypothesized that ruptured lysosomes cannot reseal after α-syn induced rupture. We tested this hypothesis using a triple colocalization analysis between lysosomal markers, labeled α-syn aggregates, and labeled rupture events. Last, we hypothesized that calcium-dependent lysosomal exocytosis may explain the release of α-syn. This mechanism of α-syn release was studied by inducing calcium influx while imaging labeled lysosomes and their contents through TIRF-M.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

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