Fig. 5

Vascular endothelial growth factor (VEGF)-A production by neurotrophically induced MPCs (nMPC) and endothelial cells (EC) positively affects neurite extension. a,c,e Dorsal root ganglia (DRG) neurite extensions in the presence of conditioned medium (CM) and immunoglobulin G (IgG) control antibody. b,d,f DRG neurite extensions in the presence of CM and α-VEGF-A antibodies (VEGF-A immunodepletion). Compared to nonspecific IgG control (a), selective removal of VEGF-A from a positive control consisting of exogenous VEGF-A (b) resulted in the loss of neurite growth induction, validating the effectiveness of VEGF-A immunodepletion. VEGF-A immunodepletion of CM derived from nMPC (d) and EC (f) decreased observed neurite extensions compared to IgG-treated mixtures (c and e, respectively), indicating that VEGF-A is an active component that contributes to both MPC and EC neurotrophic activities. h Quantification of neurite growth following depletion of VEGF-A. VEGF-A immunodepletion was associated with a significant decrease in CM-induced neurite outgrowth (one-way ANOVA, Tukey’s). i VEGF-A levels in CM measured by ELISA. VEGF-A was present in CM derived from both MPCs and ECs and could be removed by immunoprecipitation using VEGF-A-specific antibodies (versus control IgG antibodies). a–g Representative NEFH-stained images; scale bar = 1 mm. h,i n = 3; one-way ANOVA Tukey’s *p < 0.05, **p < 0.01