Spinal cord neural stem cells derived from human embryonic stem cells promote synapse regeneration and remyelination in spinal cord injury model rats

Spinal cord injury (SCI) is a devastating injury that significantly impairs patients' quality of life. To date, there is no effective treatment to mitigate nerve tissue damage and restore neurological function. Neural stem cells (NSCs) derived from human embryonic stem cells (hESCs) are considered an important cell source for reconstructing damaged neural circuits and enabling axonal regeneration. Recent preclinical studies have shown that NSCs are potential therapeutic cell sources for neuroprotection and neuroregeneration in SCI animal models. NSCs can be derived from different sources and the spinal cord-specific NSCs have a higher potential for the regeneration of SCI. However, the long-term therapeutic efficacy of spinal cord-specific NSCs remains unproven. Here, we generated human spinal cord NSCs (hSCNSCs) and investigated the effects of transplanted hSCNSCs on the repair of the SCI model rats for 60 days. The transplanted hSCNSCs improved BBB scores, reduced the lesion area and promoted an increase in the number of Nestin-positive cells in the spinal cord compared to the model rats. Meanwhile, hSCNSC transplantation promoted the expression of synaptophysin, a synaptic signature protein and MBP, a protein associated with remyelination. Interestingly, BAF45D, a chromatin remodelling factor that contributes to the induction of hSCNSCs with region-specific spinal cord identity, were increased by the hSCNSC transplantation. In addition, conditioned medium derived from the hSCNSCs also promoted regenerative repair of the injured spinal cord. These results demonstrate that hSCNSCs may play a critical role in the regenerative repair of SCI.