Determining the Role of Notch Signaling in Atoh1 Lineage Cell Fate Decisions

About This Grant

Project Summary The brainstem relays information between the brain and the spinal cord, regulating vital autonomic functions. Like other tissues, the brainstem is vulnerable to malformation and disease. Yet, despite its importance, little is known about its development, making it challenging to understand brainstem pathology. Many of the neuron populations that regulate vital brainstem function arise from a homogenous progenitor pool that expresses the proneural transcription factor Atonal homolog 1 (Atoh1). Atoh1 is functionally relevant for driving migration, however, the mechanisms that regulate progenitor proliferation and prime cells for differentiation are unknown. This incomplete understanding of brainstem development has made it challenging to develop accurate in vitro models of the brainstem, thereby hindering studies aimed at elucidating disorders and disease. Recent transcriptomic mapping of embryonic mouse hindbrain development has revealed significant expression of Notch signaling genes. Notch signaling is a key regulator of cell fate decisions across neurogenesis, and it is known to regulate proneural genes such as Atoh1. Importantly, the development of in vitro models often relies on small molecule-based approaches that direct stem cell fate by mimicking native signaling environments. Yet, the specific role of Notch signaling in Atoh1 lineage development remains poorly defined, making it challenging to utilize this pathway to model development in vitro. This proposal will investigate how Notch signaling influences Atoh1 lineage progression by integrating computational transcriptomics, stem cell differentiation, and synthetic biology. The specific aims of this project are to: (1) define transcriptomic patterns of Notch signaling during brainstem development and predict regulatory function through in silico perturbation modeling; (2) engineer a novel multi-reporter stem cell line to visualize real-time Notch ligand dynamics during Atoh1-directed differentiation; and (3) modulate Notch activity in vitro to assess the impact of ligand induction on Atoh1 fate decisions. Together, this work will clarify how Notch signaling shapes Atoh1 lineage progression and establish tools to visualize and manipulate Notch signaling in vitro. These insights will provide foundational knowledge for improving in vitro brainstem models and for probing neurodevelopmental disorders linked to brainstem dysfunction.