Fig 2: Western blot results of NTs in ipsilateral DRG. (A) Western blotting bands of NGF, NT-3, BDNF, and GDNF expressions from pooled ipsilateral L4 and L5 DRGs harvested at 8 weeks after surgery. (B–E) The quantifications of corresponding western blot signals in panel (A). (**p < 0.01). BDNF, brain-derived neurotrophic factor; DRG, dorsal root ganglia; GDNF, glial cell line-derived neurotrophic factor; NSM, nerve stump implantation inside the muscle; NGF, nerve growth factor; NT-3, neurotrophin-3; NTs, neurotrophins; RPNI, regenerative peripheral nerve interface.

Fig 3: NT3P75-2 overexpression inhibits microglia activation after TBI. a Representative images of Iba1 staining in different groups (Sham, TBI, GFP-BMSCs, NT3-BMSCs, NT3P75-2-BMSCs) (scale bar, 100 µm). b Quantification analysis of Iba1-positive cells in each group (###P < 0.001, **P < 0.01, ***P < 0.001 by one-way ANOVA followed by Bonferroni’s multiple comparison test, n = 4)

Fig 4: NT3P75-2 overexpression enhances the growth of BMSCs in vitro. a Representative images of green fluorescence protein (GFP) in BMSCs after infecting with lentiviruses (GFP, NT3, or NT3P75-2) at 3 days post-infection (n = 3). b The counting data of percent of GFP-positive BMSCs in different groups. c NT3 expression levels in BMSCs after infecting with lentiviruses (GFP, NT3, or NT3P75-2) were analyzed by western blot, and the statistical data was also presented (#P < 0.05, ***P < 0.001 by one-way ANOVA followed by Bonferroni’s multiple comparison test, n = 3). d NT3 concentrations of cellular supernatant in BMSCs after infecting with lentiviruses (GFP, NT3, and NT3P75-2) were assessed by ELISA (#P < 0.05, ***P < 0.001 by one-way ANOVA followed by Bonferroni’s multiple comparison test, n = 6). e The cell growth of BMSCs after infecting with lentiviruses (GFP, NT3, or NT3P75-2) was measured by CCK8 assays (#P < 0.05, ###P < 0.001, **P < 0.01, ***P < 0.001 by two-way ANOVA followed by Bonferroni’s multiple comparison test, n = 6)

Fig 5: NT3P75-2 induction improves the cell growth rate of NSC-34 and PC12 cells in vitro. a NT3 expression levels of GFP, NT3, and NT3P75-2 in NSC-34 were analyzed by western blot, and the statistical data was also presented (#P < 0.05, *P < 0.05, ***P < 0.001 by one-way ANOVA followed by Bonferroni’s multiple comparison test, n = 3). b NT3 expression levels of GFP, NT3, and NT3P75-2 in PC12 were analyzed by western blot, and the statistical data was also presented (#P < 0.05, **P < 0.01, ***P < 0.001 by one-way ANOVA followed by Bonferroni’s multiple comparison test, n = 3). c NT3 expression levels of GFP, NT3, and NT3P75-2 in HEK293T were analyzed by western blot, and the statistical data was also presented (**P < 0.01 by one-way ANOVA followed by Bonferroni’s multiple comparison test; n.s., no significance, n = 3). d NT3 concentrations of cellular supernatant of GFP, NT3, and NT3P75-2-infected NSC-34 cells were assessed by ELISA (***P < 0.001 by one-way ANOVA followed by Bonferroni’s multiple comparison test; n.s., no significance, n = 6). e NT3 concentrations of cellular supernatant of GFP, NT3, and NT3P75-2-infected PC12 cells were assessed by ELISA (***P < 0.001 by one-way ANOVA followed by Bonferroni’s multiple comparison test; n.s., no significance, n = 6). f NT3 concentrations of cellular supernatant of GFP, NT3, and NT3P75-2-infected HEK293T cells were assessed by ELISA (#P < 0.05, ***P < 0.001 by one-way ANOVA followed by Bonferroni’s multiple comparison test, n = 6). g CCK8 assay measurement of cell growth of NSC-34 cells infected with lentiviruses of GFP, GFP-NT3, or GFP-NT3P75-2 (#P < 0.05, ##P < 0.01, ###P < 0.001, **P < 0.01, ***P < 0.001 by two-way ANOVA followed by Bonferroni’s multiple comparison test, n = 6). h CCK8 assay measurement of cell growth of PC12 cells infected with lentiviruses of GFP, GFP-NT3, or GFP-NT3P75-2 (##P < 0.01, ###P < 0.001, **P < 0.01, ***P < 0.001 by two-way ANOVA followed by Bonferroni’s multiple comparison test, n = 6). i CCK8 assay measurement of cell growth of NSC-34 cells after treatment with the supernatant of the HEK293T cells which were respectively infected with lentiviruses of GFP, NT3, or NT3P75-2 (##P < 0.01, *P < 0.05, ***P < 0.001 by two-way ANOVA followed by Bonferroni’s multiple comparison test, n = 6). j CCK8 assay measurement of cell growth of PC12 cells after treatment with the supernatant of the HEK293T cells which were respectively infected with lentiviruses of GFP, NT3, or NT3P75-2 (###P < 0.001, **P < 0.01, ***P < 0.001 by two-way ANOVA followed by Bonferroni’s multiple comparison test, n = 6)