SCN2A contributes to oligodendroglia excitability and development in the mammalian brain

Spiking immature oligodendrocytes (OLs), referred to as spiking OLs, express voltage-activated Na(+) channels (Na(v)) and K(+) (K(v)) channels, endowing a subpopulation of OLs with the ability to generate Na(v)-driven spikes. In this study, we investigate the molecular profile of spiking OLs, using single-cell transcriptomics paired with whole-cell patch-clamp recordings. SCN2A, which encodes the channel Na(v)1.2, is specifically expressed in spiking OLs in the brainstem and cerebellum, both in mice and in Olive baboons. Spiking OLs express lineage markers of OL progenitor cells (OPCs) and pre-myelinating OLs, indicating they belong to a transitional stage during differentiation. Deletion of SCN2A reduces the Na(v) current-expressing OL population and eliminates spiking OLs, indicating that SCN2A is essential for spiking in OLs. Deletion of SCN2A does not impact global OL proliferation but disrupts maturation of a subpopulation of OLs, suggesting that Na(v)1.2 is involved in heterogeneity in OL lineage cells and their development.