Human-induced pluripotent stem cell-derived neural stem/progenitor cell ex vivo gene therapy with synaptic organizer CPTX for spinal cord injury

The transplantation of neural stem/progenitor cells (NS/PCs) derived from human induced pluripotent stem cells (hiPSCs) has shown promise in spinal cord injury (SCI) model animals. Establishing a functional synaptic connection between the transplanted and host neurons is crucial for motor function recovery. To boost therapeutic outcomes, we developed an ex vivo gene therapy aimed at promoting synapse formation by expressing the synthetic excitatory synapse organizer CPTX in hiPSC-NS/PCs. Using an immunocompromised transgenic rat model of SCI, we evaluated the effects of transplanting CPTX-expressing hiPSC-NS/PCs using histological and functional analyses. Our findings revealed a significant increase in excitatory synapse formation at the transplantation site. Retrograde monosynaptic tracing indicated extensive integration of transplanted neurons into the surrounding neuronal tracts facilitated by CPTX. Consequently, locomotion and spinal cord conduction significantly improved. Thus, ex vivo gene therapy targeting synapse formation holds promise for future clinical applications and offers potential benefits to individuals with SCI.

Building synapses: Using a synthetic approach to bridge synaptic membranes

Synapses are specialized cellular junctions essential for communication between neurons. Synapse loss occurs in many neurodegenerative diseases. Harnessing our molecular knowledge of the development and maintenance of synapses, Suzuki et al. present the first comprehensive attempt to use a synthetic protein to bridge the pre- and postsynaptic membranes¹. They show that this powerful approach can stimulate the formation of pre- and postsynaptic specializations in vitro, rescue synaptic deficits of mutant mice in vivo, and ameliorate synapse loss and behavioral abnormalities in both Alzheimer's disease and spinal cord injury mouse models.