Axonally Derived Neuregulin-1 Is Required for Remyelination and Regeneration after Nerve Injury in Adulthood (original) (raw)

2011, Journal of Neuroscience

Neuregulin-1 (NRG1) plays a crucial role in axoglial signaling during the development of the peripheral nervous system, however its importance in adulthood following peripheral nerve injury remains unclear. We utilised Single-neuron Labelling with Inducible Cre-mediated Knockout (SLICK) animals, which enabled visualisation of a subset of adult myelinated sensory and motoneurons neurons in which Nrg1 was inducibly mutated by tamoxifen treatment. In uninjured mice, NRG1 deficient axons and the associated myelin sheath were normal and the neuromuscular junction demonstrated normal apposition of pre-and postsynaptic components. Following sciatic nerve crush, NRG1 ablation resulted in severe defects in remyelination: axons were either hypomyelinated or had no myelin sheath. NRG1 deficient axons were also found to regenerate at a slower rate. Following nerve injury the neuromuscular junction was reinnervated, however excess terminal sprouting was observed. Juxtacrine Neuregulin-1 signaling is therefore dispensable for maintenance of the myelin sheath in adult animals but has a key role in reparative processes following nerve injury.