The molecular underpinnings of OL and myelin changes with ageing are still being elucidated. These findings may reflect in part the epigenetic changes in the OL lineage with ageing, which contribute to poor remyelination95. Transcriptional profiling of rodent OLs with ageing suggests increased engagement of pathways related to antigen presentation, phagocytosis, and interferon signaling96,97. Our own transcriptomic data indicated that pediatric human OLs (<5 years of age), while expressing mature lineage markers, still express developmental markers suggesting they are less mature than their adult counterparts98. The pediatric OLs showed increased expression of immune regulatory genes, as observed in comparative studies with mature OLs99. Our study also showed increased expression of metabolism-related genes in human adult vs pediatric OLs98, perhaps reflecting the extended state of myelin production in the former.
