Astrocytes populating the deep cerebellar nuclei show unique developmental and molecular profile

The role of glial cells in the functioning of the central nervous system is pivotal in ensuring neurons an adequate environment; the cerebellum is central in the motory-sensor signal integration and possesses a peculiar cytoarchitecture which is gathering increasing interest. Among cerebellar glial cells, Astrocytes of the deep cerebellar nuclei (CNA) have been neglected in the past years and there is a general lackness of data regarding their role, development and molecular profile. Recently our lab has provided a single cell RNA analysis of CNAs giving some insight on their transcriptome. In order to enrich our knowledge regarding this cell population and confirm our observation from the scRNA, we exploited hGFAP::GFP mice animal model encoding the GFP gene under the control of the human glial fibrillar acidic protein (GFAP) gene promoter, characteristic of astrocytes. We performed immunohistochemistry and proliferation assay at different post-natal days to investigate CNA proliferation and marker expression. Our results show that CNA are indeed peculiar in their development and gene expression. Proliferation assays revealed that CNA experience an initial wave of proliferation in the first postnatal week that stops at P7. Among astrocytes populating the cerebellum they showed a proliferation rate closer to white matter astrocytes, different instead from Bergmann glia and granular layer. Moreover, they show to possess unique molecular features for an astrocytic population. CNAs showed total absence of one of the main astrocytic markers GFAP, while, at the same time, expressing and maintaining Olig2 TF typical of motorneurons and oligodendrocytes. On top of that we could assess the expression of GAT-3, GABA transporter, to be found solely in CN.