Functionally distinct subgroups of Oligodendrocyte precursor cells integrate neural activity and execute myelin formation

Neuronal activity can regulate the formation of new myelin by controlling division and differentiation of oligodendrocyte precursor cells (OPCs). If activity directly instructs OPCs to differentiate or whether this process underlies a more complex regulation in unclear, because it is not known if OPCs with different functions exist. By following lineage formation of individual OPC clones, single cell RNA sequencing, in vivo calcium imaging and manipulation of neural activity, we show that OPCs in the zebrafish spinal cord can be divided into two functional entities. One subgroup forms elaborate process networks and exhibits a high degree of calcium signalling activity, but infrequently differentiates, despite contact with permissive axons. Instead, these OPCs can divide in an activity and calcium dependent manner to produce another subgroup of OPCs, which readily differentiates and which shows less elaborate, more dynamic processes, and less calcium signaling activity. Our data reveal functional diversity within the OPC population in responding to neural activity and show that activity regulates proliferation of a subset of OPCs that is distinct from the cells that will differentiate, with implications for myelin development, plasticity, and repair. Single-cell RNA sequencing from zebrafish with genetically labelled Oligodendrocyte Precursor Cells was carried out to reveal the genetic heterogeneity of this population. The transcriptomic data will be supplemented with RNA in situ hybridization and immunofluorescence stainings to validate candidate markers of subopulations, and in vivo live cell imaging data to map cell fates. Oligodendrocyte Precursor Cells from Tg(olig1:memEYFP) transgenic zebrafish at 5 days post fertilization were FACS sorted in 384-well plated containing cell lysis buffer and subsequently processed for SmartSeq2