Neuromyelitis optica spectrum disorder (NMOSD) is a severe inflammatory
autoimmune disease of the central nervous system that is manifested as secondary myelin loss. Oligodendrocyte progenitor cells (OPCs) are the principal source of myelinating oligodendrocytes (OLs) and are abundant in demyelinated regions of NMOSD patients, thus possibly representing a cellular target for pharmacological intervention. To explore the therapeutic compounds that enhance myelination due to endogenous OPCs, we screened the candidate drugs in mouse neural progenitor cell (NPC)-derived OPCs. We identified drug
edaravone, which is approved by the Food and Drug Administration (FDA), as a promoter of OPC differentiation into mature OLs.
Edaravone enhanced remyelination in organotypic slice cultures and in mice, even when
edaravone was administered following NMO-
IgG-induced
demyelination, and ameliorated motor impairment in a systemic mouse model of NMOSD. The results of mechanistic studies in NMO-
IgG-treated mice and the biopsy samples of the brain tissues of NMOSD patients indicated that the
mTORC1 signaling pathway was significantly inhibited, and
edaravone promoted OPC maturation and remyelination by activating
mTORC1 signaling. Furthermore, pharmacological activation of
mTORC1 signaling significantly enhanced myelin regeneration in NMOSD. Thus,
edaravone is a potential therapeutic agent that promotes lesion repair in NMOSD patients by enhancing OPC maturation.