miR-155 Deletion in Mice Overcomes Neuron-Intrinsic and Neuron-Extrinsic Barriers to Spinal Cord Repair

This research investigates how a small RNA molecule called miR-155 affects spinal cord injury repair in mice. The study found that deleting miR-155 improves axon growth and reduces inflammation after spinal cord injury. Macrophages lacking miR-155 have altered inflammatory capacity, which enhances neuron survival and axon growth of cocultured neurons. In addition, independent of macrophages, adult miR-155 KO neurons show enhanced spontaneous axon growth. The results suggest that miR-155 is a potential therapeutic target for spinal cord injury and other central nervous system diseases.

• 1
  Deleting miR-155 attenuates inflammatory signaling in macrophages, reduces macrophage-mediated neuron toxicity, and increases macrophage-elicited axon growth.
• 2
  miR-155 deletion increases spontaneous axon growth from neurons; adult miR-155 KO dorsal root ganglion (DRG) neurons extend 44% longer neurites than WT neurons.
• 3
  In vivo, miR-155 deletion augments conditioninglesion-induced intraneuronal expression of SPRR1A, a regeneration-associated gene.