Small-molecule-induced epigenetic rejuvenation overcomes myelinogenic barriers and stimulates myelin repair [HiChIP]

Failure of oligodendrocytes to remyelinate underlies diseases such as multiple sclerosis (MS). We found that epigenetic silencing prevents oligodendrocytes from producing myelin sheaths in demyelinating MS lesions. Here, we developed a transgenic reporter system to identify a small-molecule epigenetic modulator that stimulates oligodendrocyte maturation and myelin ensheathment in vitro. This compound promoted remyelination in animal models of MS and myelination of regenerated axons and increased myelin sheath lengths in human iPSC-derived organoids. Multi-omics analyses revealed that the compound induced an enhancer/super-enhancer landscape that upregulates crucial myelinogenesis-associated pathways, including RRAS2-AKT signaling, driving actin depolymerization necessary for myelin ensheathment. Strikingly, the compound also induced phase-separated nuclear condensates of SREBP1/2, which concentrate transcriptional co-activators to drive lipid and cholesterol biosynthesis. Silencing expression of a potential target of the small molecule, HDAC3, facilitated robust myelination and remyelination. Our findings suggest that small-molecule-modulated epigenome rejuvenation relieves epigenetic silencing barriers and promotes myelin repair. Hichip of rat iOLs treated with veh or 26C with H3K27ac antibody