RESUMO
Recently, we showed that Schwann cells transfer ribosomes to injured axons. Here, we demonstrate that Schwann cells transfer ribosomes to regenerating axons in vivo. For this, we used lentiviral vector-mediated expression of ribosomal protein L4 and eGFP to label ribosomes in Schwann cells. Two approaches were followed. First, we transduced Schwann cells in vivo in the distal trunk of the sciatic nerve after a nerve crush. Seven days after the crush, 12% of regenerating axons contained fluorescent ribosomes. Second, we transduced Schwann cells in vitro that were subsequently injected into an acellular nerve graft that was inserted into the sciatic nerve. Fluorescent ribosomes were detected in regenerating axons up to 8 weeks after graft insertion. Together, these data indicate that regenerating axons receive ribosomes from Schwann cells and, furthermore, that Schwann cells may support local axonal protein synthesis by transferring protein synthetic machinery and mRNAs to these axons.
Assuntos
Axônios/fisiologia , Regeneração Nervosa/fisiologia , Ribossomos/metabolismo , Células de Schwann/ultraestrutura , Neuropatia Ciática/cirurgia , Animais , Axônios/metabolismo , Axônios/patologia , Transporte Biológico/fisiologia , Lateralidade Funcional , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Eletrônica de Transmissão , Compressão Nervosa/métodos , Proteínas de Neurofilamentos/metabolismo , Ratos , Ratos Endogâmicos Lew , Ribossomos/ultraestrutura , Células de Schwann/patologia , Células de Schwann/transplante , Neuropatia Ciática/etiologia , Fatores de Tempo , Transdução Genética/métodosRESUMO
Schwann cells play pivotal roles in the development and maintenance of the peripheral nervous system. Here, we show that intact sciatic nerve axons of mice contain a small population of ribosomes, which increases by several orders of magnitude when axons are desomatized (severed from their cell bodies). We furthermore demonstrate, using the Wallerian degeneration slow mouse as a model, that Schwann cells transfer polyribosomes to desomatized axons. These data indicate that Schwann cells have the propensity to control axonal protein synthesis by supplying ribosomes on local basis.