Axonal plasticity in response to active forces generated through magnetic nanopulling

Summary Mechanical force is crucial in guiding axon outgrowth, before and after synapse formation. This process is referred to as “stretch-growth”. However, how neurons transduce mechanical inputs into signaling pathways remains poorly understood. Another open question is how stretch-growth is coupled in time with the intercalated addition of new mass along the entire axon. Here, we demonstrate that active mechanical force generated by magnetic nano-pulling induces a remodeling of the axonal cytoskeleton. Specifically, the increase in the axonal density of microtubules leads to an accumulation of organelles and signaling vesicles which, in turn, promotes local translation by increasing the probability of assembly of the “translation factories”. The modulation of axonal transport and local translation sustains enhanced axon outgrowth and synapse maturation.