Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China, China (People's Republic)
Abstract: Spinal cord injury (SCI) leads to locomotor deficits and neuropathic pain (NP). Ventral spinal V3 glutamate neurons are integral components of the central pattern generator (CPG) that generate the rhythm and pattern of locomotion, whereas the loss of dorsal spinal dI4 GABA neurons contributes to the NP. Here, human pluripotent stem cells (hPSCs) were differentiated into V3 and dI4 neurons in vitro. Six months after transplantation into the lesion cavity of the contused rat T10 spinal cord, human V3 and dI4 neurons extended numerous axons mainly into the ventral and dorsal horn of rat lumbar spinal cord, respectively. Human dI4 neurons form inhibitory synapses with rat sensory interneurons and nociceptive projection neurons and form presynaptic inhibition synapses with rat primary sensory afferents, whereas human V3 neurons form excitatory synapses with rat CPG neurons including V3, V2a, and V1 neurons and motor neurons. Human dI4 neurons are innervated by rat supraspinal descending pain modulation centers, including the raphe magus, dorsal raphe and rostral ventral medulla, whereas human V3 neurons are innervated by rat supraspinal motor command centers, including the corticospinal tract, reticulospinal tract and vestibulospinal tract. Functionally, NP in rats including mechanical allodynia and thermal hyperalgesia were alleviated by human dI4 neurons but not V3 neurons, whereas locomotion in rats was restored by human V3 neurons but not dI4 neurons. Importantly, recovered locomotion and alleviated NP were lost after DREADD-induced inactivation of human V3 and dI4 neurons. Finally, human dI4 and V3 neurons survive long-term, mature and integrate into the injured rhesus monkey spinal cord. These results suggest that the transplantation of hPSC-derived spinal V3 and dI4 neurons can restore locomotion and alleviate NP after SCI and highlight the importance of the regional specificity of transplanted neurons for the treatment of neurological disorders.
Funding Source: Ministry of Science and Technology of China [STI2030-Major Projects 2022ZD0204700],National Natural Science Foundation of China [82301572].
