The capacity to regenerate following axonal injury greatly varies amongst the different neuronal subtypes. While central neurons are generally assumed to be incapable of spontaneous regeneration, neurons of the peripheral nervous system encounter a growth-permissive milieu. Simultaneously, several studies have demonstrated de novo protein synthesis in injured peripheral axons locally providing the components necessary for an immediate regenerative response. Whereas the required mRNAs were shown to originate from the neuron's soma, the source of axonal ribosomes remained obscure.
We generated the so called “RiboTracker” mouse line expressing ribosomal protein L4 tagged with tdTomato (L4-tdTomato) in distinct cell types when crossed to specific Cre mice. We found that ribosomes are predominantly transferred from Schwann cells to peripheral axons following injury in vivo. In coculture-approaches using RiboTracker glial cells and wild type PNS or CNS tissues, we were also able to demonstrate a glia-to-axon transfer of L4-tdTomato+ ribosomes. Moreover, our observations strongly suggest vesicle-mediated transfer mechanisms of glial ribosomes injured axons (Müller*, Schnatz*, et al., 2018, Glia).
A predominantly glial origin of axonal ribosomes after nerve injury. Müller K*, Schnatz A*, Schillner M, Woertge S, Müller C, von Graevenitz I, Waisman A, van Minnen J, Vogelaar CF.Glia. 2018 Aug;66(8):1591-1610. doi: 10.1002/glia.23327. Epub 2018 Mar 25.PMID: 29575063