Progenitor Timing Shapes NG2-Glia Fate and Oligodendrocyte Differentiation

ABSTRACT The developmental identity and fate of NG2-glia remain debated: are they transient oligodendrocyte precursors or a distinct, self-renewing glial population? Here, we examined how the temporal origin of progenitors influences NG2-glia and oligodendrocyte lineages in the dorsal cortex. Using in utero and postnatal StarTrack electroporation at E12, E14, E16, and P0, we traced their progeny to P30 and P90, performing a clonal analysis in adult mouse brains. Progenitors labeled at E16 generated significantly larger and more widely dispersed NG2-glia clones, whose contribution increased from P30 to P90, suggesting enhanced proliferative capacity. In contrast, P0-derived progenitors showed reduced NG2-glia maintenance and a strong bias toward oligodendrocyte differentiation, forming larger OL clones. Clonal heterogeneity, including mixed NG2-glia/OL clones, was observed across all stages but peaked at E16. These results identify E16 as a critical window for NG2-glia expansion and self-renewal, while P0 marks a transition toward oligodendrocyte lineage restriction, establishing a developmental framework for adult NG2-glia heterogeneity and maybe a regenerative potential. Significance Statement We show that developmental timing and progenitor identity shape NG2-glia and oligodendrocyte fates in the postnatal cortex. NG2 progenitors at E16 generate expansive, widely dispersed NG2-glia clones, whereas P0 progenitors bias toward oligodendrocyte differentiation, revealing critical temporal windows that establish long-term glial heterogeneity. Competing Interest Statement The authors have declared no competing interest. Footnotes Conflict of interest statement: Authors do not declare any conflict of interest. Financial support provided by Spanish grants PID2022-136882NB-I00 and PID2019-105218RB-I00 funded MCIN/AEI/10.13039/501100011033 for LLM and BES-2017-082917 for ACO.