Grant: Project Grant

Amid the great diversity of neurodegenerative disorders, there is a growing body of evidence suggesting that synapses are preferentially altered early in the disease process. Though there is compelling evidence that de-innervation of neuromuscular junctions (NMJ) occurs early and throughout the clinical progression of amyotrophic lateral sclerosis (ALS), the cellular mechanisms that result in loss of NMJ connectivity remain poorly understood. To investigate these defects, my laboratory uses zebrafish ALS models. This animal is uniquely suited for investigations pertaining to the fundamental nature of NMJ defects in ALS as it permits investigations of in vivo physiological function resulting from the expression of mutant ALS-causing genes. We study two ALS genes: TARDBP and FUS, these encode the RNA-binding proteins TDP-43 and FUS respectively, and in ALS mutations in these two genes are believed to interfere with the normal processing of transcripts involved with synaptic function. We have developed genetic animal models of ALS in which analogous disease-causing mutations have been CRISPR-edited into tardbp (encoding zebrafish tdp-43) and fus (encoding zebrafish fus). These models develop an ALS-like motor phenotype and die prematurely. We propose to investigate the synaptic transcripts processed by tdp-43 and fus specifically in the spinal cords and motor neuron cell population and examine how these transcripts are processed differently in our ALS models. In parallel, we will use an array of physiological approaches to explore physiological defects that arise in synaptic function at the NMJ. We propose that furthering our understanding of synaptic defects arising in ALS will provide the necessary foundation for a more complete understanding of the disease, which we believe is needed for therapeutic development.