Investigating the Effects of Tau Expression on Chiasmatic Ensheathing Glia in Drosophila melanogaster

Abstract

In 2023, 7 million Americans were reportedly living with Alzheimer’s Disease, and Alzheimer’s-associated deaths are rising. Alzheimer’s Disease and other neurodegenerative diseases are characterized by a buildup of the protein tau, leading to their classification as tauopathies. Normally, tau binds to and stabilizes microtubules; in these diseases, tau proteins bind to each other and form harmful aggregates. Most current research focuses on the effects of tau aggregation on neurons and neuronal function, leaving a research gap in the effects of tau on glial cells, although these cells are responsible for a wide range of functions, including neuronal support and environmental maintenance. In the human brain, there are five main subtypes of glial cells. The Drosophila melanogaster brain also contains five subtypes, with similar functions to human glial counterparts. Previous research from the Colodner lab has shown that tau expression in Drosophila differentially affects some glial subtypes, and this project investigated the effects of human tau expression on chiasmatic ensheathing glia. We hypothesized that chiasm-specific tau expression would lead to toxicity of these cells, shown by decreased cell counts. Our results showed that chiasm-specific tau expression led to significant decreases in ensheathing and chiasmatic ensheathing glia, as well as phenotypic changes in both inner and outer chiasm glia. This tau-associated toxicity could shed light on potential mechanisms behind some of the vision and sleep deficits seen in tauopathy patients.