Morphological diversification and functional maturation of human astrocytes in glia-enriched cortical organoids transplanted in the mouse brain

Astrocytes, the most abundant glial cell type in the brain, are underrepresented in traditional cortical organoid models due to the delayed onset of cortical gliogenesis. Here, we introduce a novel glia-enriched cortical organoid model that exhibits accelerated astrogliogenesis. We demonstrated that induction of a gliogenic switch in a subset of progenitors enabled rapid derivation of astroglial cells, which account for 25-31% of the cell population within eight to ten weeks of differentiation. Intracerebral transplantation of these organoids reliably generated a diverse repertoire of cortical neurons and anatomical subclasses of human astrocytes. Spatial transcriptome profiling identified layer-specific expression patterns among distinct subclasses of astrocytes within the organoid transplants. Using an in vivo acute neuroinflammation model, we identified a subpopulation of astrocytes that rapidly activates proinflammatory pathways upon cytokine stimulation. Additionally, we demonstrated that CD38 signaling plays a crucial role in mediating metabolic and mitochondrial stress in reactive astrocytes. This model provides a robust platform for investigating human astrocyte function. Overall design: Single-nucleus RNA-Seq Single-cell RNA-Seq