Elucidating the molecular mechanisms of sensory regeneration

National Institute Of Neurological Disorders And Stroke

Investigators

Abstract

Renovation of lab facilities in the Porter Research Building were completed at the end of September 2021, at which point experiments were able to resume, having been delayed by pandemic- and other construction-related setbacks. Since opening, the Molecular Neurobiology Section has built on past accomplishments using a variety of approaches to elucidate the molecular and cellular mechanisms regulating olfactory stem cells and olfactory neurogenesis in the mouse. Previous studies in the lab, which used single cell sequencing to identify potential genes involved in olfactory stem cell activation, landed on two promising candidate intracellular signaling pathways -- EGF and Wnt signaling. In one current area of inquiry, the lab is using genetic gain- and loss-of-function mouse models to investigate the roles of Wnt and EGF signaling in promoting stem cell self-renewal, proliferation and differentiation. These studies will combine single-cell transcriptomics with epigenomics analysis of the genetic gain- and loss-of-function models to dive deeper into elucidating the gene regulatory networks involved in olfactory stem cell dynamics. In addition, the lab has established an in vitro model of olfactory epithelium regeneration. This approach will provide an alternative to the in vivo gain- and loss-of-function models that will allow for higher throughput analysis of potential regulators of olfactory stem cell dynamics and differentiation trajectories. Finally, working with our collaborators, the lab is investigating the hypothesis that there is a sub-population of quiescent olfactory stem cells that are primed for activation. Using statistical analysis of previously generated RNA-seq and ATAC-seq data, the lab has identified candidate genes that are relatively silent but appear to occupy accessible chromatin in uninjured stem cells, which then become expressed in stem cells upon injury. The lab is currently validating these candidates using multiplex fluorescent in situ hybridization. Future studies will employ clonal analysis in vivo and in vitro to determine whether and how Wnt and EGF signaling regulate stem cell fate. In addition, the lab has begun to apply single cell RNA sequencing and other single cell technologies to lineage-traced FACS-purified olfactory cells to elucidate the gene regulatory networks important for distinct developmental trajectories of cells as they transition from early stem cell states, through intermediate progenitors and then through terminal differentiation.