The cholesterol transporter NPC1 is essential for epigenetic regulation and maturation of oligodendrocyte lineage cells

Cholesterol is required for oligodendrocyte maturation and CNS myelination. Here, we demonstrate an essential role for the intracellular cholesterol transporter NPC1 in these processes. NPC1 functions in late endosomes and lysosomes to efflux unesterified cholesterol, and its deficiency causes Niemann-Pick disease Type C, an autosomal recessive lysosomal disorder characterized by progressive neurodegeneration and early death. To identify cell types and pathways affected early in pathogenesis, we performed single nuclear RNA-seq on the forebrain of Npc1-/- mice at P16. This analysis uncovered striking transcriptional changes in the oligodendrocyte lineage during the period of developmental myelination, accompanied by diminished maturation of myelinating oligodendrocytes. Unexpectedly, we identified a significant upregulation of genes associated with neurogenesis and synapse formation in Npc1-/- oligodendrocyte lineage cells, reflecting diminished gene silencing by H3K27me3 and H3K9me3. Npc1-/- oligodendrocyte progenitor cells reproduced impaired maturation in vitro and this phenotype was rescued by treatment with GSK-J4, a small molecule inhibitor of H3K27 demethylases. Moreover, mobilizing stored cholesterol in Npc1-/- mice by a single administration of 2-hydroxypropyl-beta-cyclodextrin at P7 rescued myelination, epigenetic marks, and oligodendrocyte gene expression. Our findings highlight an essential role for NPC1 in oligodendrocyte lineage maturation and epigenetic regulation, and they identify new potential targets for therapeutic intervention.