Spinal muscular atrophy (SMA) is an intractable disease characterized by a progressive loss of spinal motor neurons, which leads to skeletal muscle weakness and atrophy. Currently, there are no curative agents for SMA, although it is understood to be caused by reduced levels of survival motor neuron (SMN) protein. Additionally, why reduced SMN protein level results in selective apoptosis in spinal motor neurons is still not understood. Our purpose in this study was to evaluate the therapeutic potential of edaravone, a free radical scavenger, by using induced pluripotent stem cells from an SMA patient (SMA-iPSCs) and to address oxidative stress-induced apoptosis in spinal motor neurons. We first found that edaravone could improve impaired neural development of SMA-iPSCs-derived spinal motor neurons with limited effect on nuclear SMN protein expression. Furthermore, edaravone inhibited the generation of reactive oxygen species and mitochondrial reactive oxygen species upregulated in SMA-iPSCs-derived spinal motor neurons, and reversed oxidative-stress induced apoptosis. In this study, we suggest that oxidative stress might be partly the reason for selective apoptosis in spinal motor neurons in SMA pathology, and that oxidative stress-induced apoptosis might be the therapeutic target of SMA.
Keywords: Edaravone; Induced pluripotent stem cells; Oxidative stress; Spinal motor neuron; Spinal muscular atrophy; Survival motor neuron protein.
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