Modulation of Neural Stem Cell Fate by Reactive Astrocytes

Overview

The glial scar that forms after ischemic injury creates a structurally and functionally complex barrier, yet how it regulates neural stem cell (NSC) fate remains unclear. Single-cell RNA sequencing analysis of a mouse model showed glial scar formation increased NSC terminal differentiation and depleted the NSC pool. Reactive astrocytes are key scar components, and traditionally classified as A1 (neurotoxic) or A2 (neuroprotective). TNFα, a pro-inflammatory cytokine secreted around the scar, is upregulated between NSCs and A1 astrocytes, suggesting A1 astrocytes modulate NSC fate via TNF signaling. In vitro, NSCs co-cultured with A1 astrocytes or exposed to A1-conditioned media biased toward NG2+ oligodendrocyte precursor cell (OPC) differentiation, which localizes to the scar periphery. TNFα alone similarly promoted OPC lineage commitment, supporting a model in which A1-derived TNFα drives NSC-to-OPC differentiation. A1 astrocytes were generated by stimulating homeostatic astrocytes with microglia-derived cytokines, leading to TNFα upregulation by RT-qPCR and sustained secretion by ELISA. Only strongly stimulated astrocytes maintained elevated TNFα after one week, indicating a threshold-dependent feedback mechanism. In contrast, astrocytes stimulated under A2 conditions (TNFα + IL-1β) did not sustain TNFα secretion. Finally, pharmacological inhibition of astrocyte activation with dantrolene or salubrinal suppressed TNFα release, abrogating its effect on NSCs. Together, these results suggest that A1 astrocyte–NSC interactions, mediated by TNFα-driven NSC-to-OPC conversion, contribute to the glial scar’s protective architecture while limiting regenerative potential and depleting the NSC pool.

Competition history

CSEF 2026 Medicine & Physiology (Senior Division) · Entry S-15-11

Related projects

ISEF · 2026