Dissecting Reactive Astrocyte Responses: Lineage Tracing and Morphology-based Clustering

Abstract

Brain damage triggers diverse cellular and molecular events, with astrocytes playing a crucial role in activating local neuroprotective and reparative signaling within damaged neuronal circuits. Here, we investigated reactive astrocytes using a multidimensional approach to categorize their responses into different subtypes based on morphology using the StarTrack lineage tracer, single-cell imaging reconstruction and multivariate data analysis. Our findings revealed three profiles of reactive astrocyte responses affecting cell size- and shape- related morphological parameters: "moderate," "strong," and "very strong". We also explored the heterogeneity in astrocyte reactivity, with a particular emphasis in the spatial and clonal distribution. Our research highlights the importance of the relationships between the different astrocyte subpopulations with their reactive responses, showing an enrichment of protoplasmic and fibrous astrocytes within the "strong" and "very strong" subtypes. Overall, our study contributes to a better understanding of astrocyte heterogeneity in response to an injury. By elucidating the diverse reactive responses among astrocyte subpopulations, we pave the way for future research aimed at uncovering novel therapeutic targets for mitigating the effects of brain damage and promoting neural repair.