Vesicular Acetylcholine Transporter Function in the Central Nervous System

Delaware State University, Dover DE

Investigators

Abstract

Regulation of the synthesis, storage, release and degradation of the neurotransmitter acetylcholine (ACh) is essential for normal organismal capabilities such as the ability to move, think and remember. Scientists presently understand the major elements of the cellular and molecular machinery required for these aspects of brain function, which include the molecular complex that this project is focused on, called the vesicular acetylcholine transporter (VAChT). VAChTs are responsible for transporting acetylcholine into synaptic vesicles inside nerve terminals so that it can be released onto its target cells. However, the detailed mechanisms through which VAChTs mediate this transport process remain unclear, as does the role that VAChT-related changes in acetylcholine release may play in regulating behavioral changes. This project uses the outstanding genetic resources that fruit flies possess for studying the acetylcholine regulation system to determine how changes in VAChT affect acetylcholine release and the regulation of the behaviors described above. This project also utilizes a wide range of sophisticated tools and methodologies (including the ability to record electrical activity from fly brain cells) to train undergraduate and graduate students from historically under-represented minority backgrounds, equipping them with an up-to-date set of transferrable skills in Science, Technology, Engineering and Math (STEM), and broadening the participation of minorities in the advanced STEM workforce. The project also includes a strong focus on research training and education of K-12 students through a virtual internship program. The main objective of this project is to determine how specific changes in the vesicular acetylcholine transporter (VAChT) alter acetylcholine (Ach) release by using a collection of genetic alterations available in Drosophila. A variety of experiments employing this mutation and overexpression collection will help elucidate the relationship between ACh release and ACh-linked behaviors. The central hypothesis is that an inverted V-shaped model underlies ACh synaptic release, such that strong decreases in or overexpression of the transporter cause severe defects in synaptic physiology and ACh-linked behavior, while mild increases in VAChT expression will enhance synaptic activity. The work will test this hypothesis using three Specific Aims. Aim 1 will determine how specific changes in VAChT affect that protein’s expression, its activity, and the levels of ACh. Aim 2 is focused on determining how changes in VAChT expression affect synaptic vesicles (SV) by testing the hypothesis that graded increases in VAChT upregulate both SV release and SV fusion. Aim 3 will determine the effects of graded changes in VAChT function on ACh-linked behaviors. Altogether, the project will advance our understanding of the mechanisms through which VAChT ultimately helps to mediate synaptic release. This project is jointly funded by the Organization Program, the Established Program to Stimulate Competitive Research (EPSCoR), and the Historically Black Colleges and Universities Undergraduate Program (HBCU-UP). This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.