Netrin-1 signaling for sensory axons Involvement in sensory axonal development and regeneration

During the development of the nervous system, axons from DRG neurons extend towards the spinal cord. Netrin-1, a guidance molecule, acts as a repellent to prevent these axons from growing in the wrong direction. This ensures they correctly reach their target area within the spinal cord. After entering the spinal cord, DRG axons pause before projecting to the dorsal mantle layer. Netrin-1, expressed in the dorsal spinal cord during this ‘waiting period’, helps guide the axons and prevents them from invading the dorsal spinal cord prematurely. Following spinal cord injury, sensory axons often fail to regenerate. Netrin-1 remains present at the injury site and continues to repel the axons, which might contribute to this lack of regeneration. Manipulating netrin-1 could potentially aid in treating spinal cord injuries.

• 1
  Netrin-1 acts as a chemorepellent for developing DRG axons, preventing them from projecting aberrantly toward the ventral spinal cord and ensuring correct projection toward the DREZ.
• 2
  Dorsally derived netrin-1 contributes to the correct guidance of DRG axons by preventing them from invading the dorsal spinal cord during the 'waiting period'.
• 3
  Netrin-1 may be a major inhibitor of sensory axonal regeneration after spinal cord injury, as its expression remains unchanged in the lesion site, and adult DRG neurons respond to its repulsive signals.