Investigator: Geoff Stilwell, Rhode Island College
Theme: Neuroscience
Title: Characterizing differences in tissue-specific mitochondrial function for neurodegenerative disease

Award: SURF PUI Training Award (2022-2024)
Abstract: Mitochondrial function is disrupted at early stages in neurodegenerative disease and this dysregulation contributes to fundamental changes that are part of the disease state in metabolism, innate immune responses, energy homeostasis and signaling between neurons and glia. Our work focuses on the molecular mechanisms leading to cell death in amyotrophic lateral sclerosis (ALS) and related neurodegenerative diseases. Recently, mitochondrial proteome studies have highlighted differences between mitochondrial populations pointing towards differences in function for various cell types. How mitochondrial functions differ between neurons and glia is not well characterized, and further, how different populations of mitochondria contribute to neurodegeneration is unknown.

We propose to use Drosophila as a model system for cell type specific expression of antigenic protein tags which localize to mitochondria. We will make transgenic flies to allow for the immunopurification of mitochondria in tissues expressing the mitotag construct. We will drive mitotag expression using the bipartite Gal4/UAS system and purify mitochondria from all cells, neurons, and glia. We will first establish differences in mitochondria between neurons and glia. From each population, we will characterize mitochondrial transcript expression using qRT-PCR and protein expression/localization using Western blot analysis for a suite of mitochondrial encoded and nuclear encoded genes. We will then apply similar methods to characterize mitochondrial populations in a sod1 model of ALS. Mutant SOD1 protein aggregates within mitochondria as part of a toxic mechanism of neurodegeneration. Further, we observe age-dependent mitochondrial swelling in mutant knock-in flies. These methods will make it possible to help tease apart contributions of glia versus neurons to toxicity and could serve as a proof-of-concept for other studies across a range of cell types and disease states when lines are made available to the scientific community.

Relevance: This proposal will characterize differences in mitochondria between various cell types and apply this knowledge to help determine how different cell types contribute to neurodegeneration. The project will leverage a fruitful and long-standing collaboration with Brown University and will provide undergraduates at Rhode Island College the opportunity to engage in substantive translational research.