Spinal cord regeneration — the origins of progenitor cells for functional rebuilding

The spinal cord connects the body to the brain, and injuries in mammals often lead to paralysis with limited recovery. However, some animals can regenerate their spinal cords after injury. This review examines spinal cord regeneration, focusing on how certain animals direct cells to rebuild a functional spinal cord. Ependymal glial cells, found in the spinal cord and brain, are important for spinal fluid homeostasis and regenerative repair. These cells express Sox2, which regulates stem cell pluripotency. After a spinal cord injury, these cells act like neural stem cells and multiply to regenerate the missing parts. Researchers are studying the signaling pathways that activate neural stem cell proliferation after injury. For instance, the microRNA miR-200a in axolotls prevents the upregulation of GFAP, promoting regenerative repair. Also, the mTOR signaling pathway appears crucial for neural stem cell proliferation after spinal cord injury.

• 1
  Ependymal glial cells in regeneration-competent species express Sox2 and act as neural stem cells (NSCs) after spinal cord injury, rapidly proliferating to regenerate the missing tissue.
• 2
  The microRNA miR-200a plays a key role in regulating NSC activation in axolotls by suppressing c-Jun expression, which prevents the upregulation of GFAP and promotes regenerative repair.
• 3
  The mTOR signaling pathway is significantly upregulated after spinal cord injury in Xenopus, and its inhibition impairs NSC proliferation and spinal cord regeneration, indicating its importance in cell-cycle transition.