| Project Detail |
The mechanisms through which neuronal progenitor cells in different parts of the brain acquire their identity during development are poorly understood. Neurons in different brain regions, such as the forebrain, the midbrain, and the hindbrain, are born from different progenitor domains located in the ventricular zone (VZ) along the rostro-caudal extent of the neural tube. While core molecular markers of embryonic anatomical regions such as the forebrain, midbrain, and hindbrain have been identified, the developmental molecular diversity of progenitors in distinct regions and the extent to which their identity, including their neurogenic competence, relies on cell-intrinsic vs. cell-extrinsic cues remains poorly understood. In this proposal, using state-of-the-art single-cell analysis tools, we propose to address these questions through three aims using shared readouts to define the identity and plasticity of VZ progenitors: molecular features (transcriptional /epigenetic), cell-cycling features, and single-cell electrophysiology. Morphology and connectivity will also be used to characterize the neuronal progeny of these cells. Aim1: Identifying the developmental molecular and cellular diversity of VZ progenitors along the neuraxis. We will do this by mapping the spatial diversity of VZ progenitors in the brain using multi-omic single-cell RNA and ATAC sequencing (Exps. 1.1 and 1.2), spatial transcriptomics (Exp. 1.3), cell cycle assays to assess region-specific progenitor cycling features (Exp. 1.4) and patch-clamp recordings to assess region-specific progenitor and daughter neuron electrophysiological features (Exp. 1.5).Aim2: Assessing the plasticity in the spatial identity of progenitors. We will do this using region-specific transplantations of VZ progenitors isolated with FlashTag labeling (Exp. 2.1) and using Patch-seq (Exp. 2.2), cell-cycle assays (Exp. 2.3), single-cell electrophysiological properties (Exp. 2.4), morphology and connectivity of daughter neurons (Exps. 2.5 and 2.6) as readouts of identity. Regions are here defined as the forebrain (subdivided into the dorsal pallium and subpallium) and the midbrain and hindbrain.Aim3: Manipulating region-specific VZ progenitor identity, including their neurogenic competence, using genetic gain/loss-of-function approaches (Exp. 3.1) using the parameters above as readouts (Exp. 3.2). Together, the experiments proposed here aim at providing an integrated molecular and cellular characterization of the spatial diversity and plasticity of VZ progenitors during embryonic brain development. Understanding the molecular mechanisms at play in spatial patterning and plasticity is critical not only to understand how our brains have evolved and developed, but also how abnormal developmental events may lead to human disorders such as brain malformations and neuropsychiatric disorders. |
