A SINGLE-CELL TRANSCRIPTOMIC ATLAS MAPS CEREBELLAR ASTROCYTE DIVERSITY AND UNCOVERS THE TRANSCRIPTIONAL CODE UNDERLYING THEIR MATURATION TRAJECTORIES

Astrocytes are key regulators of neural circuit development and function, with mounting evidence of substantial heterogeneity within and across brain regions. Yet, the full scope of their diversity and underlying developmental mechanisms remain unclear. To address these open questions, we leveraged the uniqueness of the mouse cerebellum, where astrocyte types and progenitor pools are well defined, and systematically mapped their molecular diversity and ontogenesis using complementary multi-modal omics - including single-cell RNA sequencing, spatial transcriptomics, trajectory inference, clonal lineage reconstruction, and regulatory network analyses.
We identified known astrocyte types and uncovered previously unrecognized subtypes with functional specialization, inferring their developmental trajectories from multiple embryonic niches and perinatal progenitor pools giving rise to fate divergent, convergent, and restricted lineages. We further predicted a composite transcriptional regulator code orchestrating this diversification at multiple levels, with modules that (i) reflect embryonic regionalization and lineages; (ii) define astroglial identity; (iii) specify Bergmann versus non-Bergmann fates; and direct astrocyte type (iv) and subtype (v) acquisition. Together, these data map and temporally organize transcriptional programs that shape astrocyte fates and provide a high-resolution model for glial diversification, poised for testing across other brain regions.