Time-lapse Microscopy to Characterize Astrocyte Precursor Cells Migration Using a Double Reporter Mouse Line

Time-lapse Microscopy to Characterize Astrocyte Precursor Cells Migration Using a Double Reporter Mouse Line

Alvin Sherman Library

Astrocytes, the most abundant non-neuronal cell type in the brain, are a diverse population of cells that play a central role in regulating synaptic activity, supporting neuronal energy demands, and modulating interactions among neurons, glia, and blood vessels. Astrocytes originate from astrocyte precursor cells (APCs) in the subventricular zone, from where they migrate to the cortex postnatally. Once in the cortex, APCs continue to proliferate and then undergo morphological and functional maturation. Using a double reporter mouse line engineered to express enhanced green fluorescent protein (eGFP) under the control of the entire glutamate transporter 1 (GLT1) gene and tdTomato (tdT) under the control of 8.3 kilobases of the human GLT1/EAAT2 promoter, we found that while eGFP labels all astrocytes, tdT only labels a subpopulation of cortical astrocytes. Here we use acute organotypic brain slices prepared from the same double-reporter mouse line to evaluate differences in the spatial and temporal characteristics of migration between APC subtypes (eGFP+/tdT+ vs eGFP+/tdT-). Time-lapse confocal microscopy was performed to track APC's migration in real time, allowing quantitative analysis of migration distance, directionality, and cortical integration. It is expected that migration trajectories will demonstrate non-random, directed movement consistent with regulated developmental signaling rather than passive dispersion. This investigation may provide direct, real-time evidence of postnatal APC's migration within intact brain tissue. This work advances our understanding of astrocyte development and establishes a basis for future studies examining molecular mechanisms that regulate glial migration during normal development and in disease states.