snRNA-Seq of optic nerve from two models of inducible demyelination.
Multiple Sclerosis (MS) is a neuroinflammatory disease characterized by demyelinated lesions in the CNS. Remyelination in MS is variable between individuals and tends to become less efficient with aging. Microglia and astrocytes are known to have critical roles in MS pathogenesis, but to what extent their activity is altered by remyelination failure remains unclear.  To determine the effects of demyelination on neuroinflammation, we use two mouse models that genetically ablate myelinating oligodendrocytes. We use the Plp1-CreERT mouse line crossed with the Myrf fl/fl mouse line to induce genetic demyelination throughout the CNS following adult tamoxifen administration. Subsequent remyelination is mediated by the proliferation and differentiation of oligodendrocyte precursor cells (OPCs) to newly formed oligodendrocytes. To assess the consequences of remyelination failure, we deleted Myrf from both mature oligodendrocytes and OPCs using Myrf fl/fl; Sox10-CreERT mice, which both induces demyelination and impairs subsequent remyelination. To characterize the glial cells in these demyelinated mice, we performed single-nucleus RNA-sequencing (snRNAseq) of optic nerves at peak demyelination, generating an atlas of non-neuronal cells including oligodendrocyte lineage cells, astrocytes, microglia, endothelial cells, pericytes, arachnoid barrier cells, vascular and leptomeningeal cells. Overall design: Optic nerves were isolated from adult Myrf fl/fl; Sox10-CreERT and Myrf fl/fl; PLP-CreERT mice and their CreERT negative control littermates at 10 weeks post tamoxifen and snap frozen. Nuclei were isolated by fluorescence-activated nuclei sorting (FANS) according to the presence or absence of RedDot signal and analyzed using snRNAseq on the 10x Genomics platform.