Barriola, S. | Search bioRxiv

bioRxiv2025

NG2-Glia Heterogeneity Across Cortical Layers

NG2-glia are a unique and heterogeneous glial cell population with diverse roles in the central nervous system. However, their morphological diversity across brain regions and cortical layers remains poorly understood. Here, we use StarTrack labeling and in utero electroporation at embryonic day 14 (E14) to reconstruct individual NG2-glial cells in the adult mouse cortex and corpus callosum. Through detailed two- and three-dimensional morphometric analyses, including Sholl analysis, principal component analysis, and hierarchical clustering, we uncover striking layer-specific patterns. NG2-glia in deep cortical layers (L5-6) exhibit significantly larger somatic areas, more elaborate arborizations, and higher process complexity compared to those in superficial layers (L1-4) and the corpus callosum. In contrast, NG2-glia in layer 1 and the corpus callosum share a compact morphology characterized by smaller somata and simplified processes, suggesting common microenvironmental constraints. Moreover, Sholl analysis, principal component analysis, and hierarchical clustering reveal distinct morphological subpopulations within the NG2-glial population and highlight heterogeneity in upper cortical layers. Comparative analyses with astrocytes reveal fundamental structural differences: NG2-glia have thinner, longer processes and larger enclosing radii but occupy smaller volumes, whereas astrocytes form denser, more compact arbors with higher branch numbers. Together, our finding establish the first comprehensive morphological atlas of cortical adult NG2-glia, highlighting region- and layer-specific adaptations that likely underlie their diverse roles in CNS physiology and repair. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=196 SRC="FIGDIR/small/666263v1_ufig1.gif" ALT="Figure 1000"> View larger version (45K): org.highwire.dtl.DTLVardef@1aad0c5org.highwire.dtl.DTLVardef@17049dborg.highwire.dtl.DTLVardef@100e966org.highwire.dtl.DTLVardef@db5b58_HPS_FORMAT_FIGEXP M_FIG C_FIG Main points- Morphological variation of NG2-glial cells by cortical layers - Cells in deep cortical layers are larger and more complex - NG2-glia in upper layers and corpus callosum share similar morphology - NG2-glia vs. astrocytes: distinct structural features

neuroscience↗

bioRxiv2025

Progenitor Heterogeneity in the Developing Cortex: Divergent and Complementary Roles of NG2-Progenitors and RGCs

Brain development is a highly coordinated process that arises from a pool of neural progenitor cells (NPCs). Traditionally, research has largely focused on Radial Glial Cells (RGCs), which produce neurons and glia. However, recent findings revealed that the progenitor landscape is more complex and heterogeneous than previously understood. Emerging evidence indicates that NG2 glia, also known as oligodendrocyte precursor cells (OPCs), may contribute to generating other cell types, including neurons and astrocytes. This suggests that NG2 glia, or a specific subset, may act as multipotent NPCs, expanding their role in brain development beyond their known lineage. We explore the cellular, molecular, and functional differences between NG2- and GFAP- expressing progenitors (NG2-NPCs and GFAP-NPCs) across different developmental stages. Using in-utero electroporation and StarTrack technology, we examined whether these progenitors represent distinct populations and analyzed how their differences influence their functional roles based on cell fate decisions. Our findings uncover functional divergence between NG2-NPCs and GFAP-NPCs, particularly regarding their cell fate decisions. While both populations contribute to the formation of neurons and glial cells, the progeny of NG2-NPCs and GFAP-NPCs differ markedly in their contributions to neurogenesis and gliogenesis. Further, we conducted a comprehensive transcriptomic analysis of NG2-NPCs and GFAP-NPCs to elucidate the molecular basis for these functional differences. This study demonstrates distinct gene expression profiles. While NG2-NPCs show enrichment for genes associated with neurogenesis and synaptic transport, GFAP-NPCs displayed upregulation of genes involved in progenitor cell maintenance. This indicates that each progenitor type is governed by distinct molecular programs, shaping their contributions to brain architecture and function. In summary, our findings underscore the divergent roles of NG2-NPCs and GFAP-NPCs in driving cellular diversity and functional maturation in brain development, providing new insights into how these progenitor populations contribute to neural diversity and brain function. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=111 SRC="FIGDIR/small/635022v1_ufig1.gif" ALT="Figure 1"> View larger version (43K): org.highwire.dtl.DTLVardef@26a85corg.highwire.dtl.DTLVardef@1f73c67org.highwire.dtl.DTLVardef@9e9767org.highwire.dtl.DTLVardef@1e62c22_HPS_FORMAT_FIGEXP M_FIG C_FIG

developmental biology↗