Molecular Signatures and Lineage Diversification of Neurogenic and Gliogenic Radial Glia in the Gyrencephalic Ferret Cortex

Human exceptional cognition stems from evolutionarily derived cortical adaptations that drive expansive neurogenesis. Deciphering these mechanisms is crucial for understanding mammalian cortical evolution. In this study, we employ the ferret model to comprehensively map molecular profiles and lineage dynamics of cortical radial glia (RGs). By applying scRNA-Seq to ferret and human cortices, we identify conserved regulatory programs underlying cortical neurogenesis and gliogenesis in mammals. Through integrated scRNA-Seq, BrdU pulse-chase labeling, and immunohistochemical approaches, we demonstrate that, similar to their human counterparts, ferret cortical outer radial glia (oRGs), exhibit enhanced ERK and PKA signaling. ERK and PKA act in a mutually reinforcing manner to boost oRG self-renewal and neurogenesis, while inhibiting gliogenesis and prolonging the neurogenic period. Furthermore, we identify regional specialization within cortical gliogenic RGs: YAP/TAZ activation drives ventricular zone truncated radial glia (tRGs) toward ependymal fate in medial cortex, whereas SHH signaling instructs lateral cortical tRGs to generate tripotential intermediate progenitor cells, which serve as a shared source of astrocytes, oligodendrocytes, and olfactory bulb interneurons. Our data support a model in which mammalian cortical neurogenesis, gliogenesis, and evolutionary expansion are co-regulated through an integrated signaling network involving ERK, PKA, YAP/TAZ, and SHH. These findings provide key insights into the molecular and cellular mechanisms driving cortical development and evolution. P3 ferret pups were deeply anesthetized, and their brains were immediately harvested and immersed in ice-cold Hanks' Balanced Salt Solution (Gibco 14175-095). The dorsal cortices were dissected into small pieces and dissociated into a single-cell suspension using the Papain Cell Dissociation Kit, following the manufacturer’s instructions (Miltenyi Biotec, catalog no. 130-092-628). Single-cell RNA sequencing (scRNA-Seq) libraries were prepared using the Chromium droplet-based sequencing platform (10X Genomics), in accordance with the manufacturer’s guidelines (manual document part number: CG00052 Rev C). The cDNA libraries were purified, quantified using an Agilent 2100 Bioanalyzer, and sequenced on an Illumina HiSeq 4000.