Axotomy induces axonogenesis in hippocampal neurons by a mechanism dependent on importin β

We characterize the previously unrecognized phenomenon of axotomy-induced axonogenesis in rat embryonic hippocampal neurons in vitro and elucidate the underlying mechanism. New neurites arose from cell bodies after axotomy and grew. These neurites were Tau-1-positive, and the injured axons showed negative immunoreactivity for Tau-1. Axonogenesis was delayed in these neurons by inhibiting the dynein–dynactin complex through the overexpression of p50. Importin β, which was locally translated after axotomy, was associated with the dynein-importin α complex and was required for axonogenesis. Taken together, these results suggest that retrograde transport of injury-induced signals in injured axons play key roles in the axotomy-induced axonogenesis of hippocampal neurons.

Research highlights
► Axotomy induces axonogenesis of hippocampal neurons.
► Retrograde transport through dynein–dynactin complex is required for axonogenesis.
► Importin β is involved in axotomy-induced axonogenesis.