Fig. 9

Signaling pathways affected by exosomal miR-199a-3p/145-5p. Exogenous exosomes from human umbilical cord mesenchymal stem cells are taken up by damaged neurons and release abundant levels of miRNA-199a-3p/145-5p, which target Cblb and Cbl mRNAs to inhibit the ubiquitination-mediated degradation of TrkA. Sustained activation of p-Erk and p-Akt leads to persistent expression of Neu-N, NF-H, β-tubulin-III, and neurite outgrowth