Fig 2: Neuropathology in treated and untreated tumors at 14 weeksPathologic analysis of schwannomas for H&E, Ki67, S100, and SOX10 in the sciatic nerve of immunodeficient mice after 10 weeks of treatment with AAV1-FLAG-merlin vector and or PBS. (A) H&E staining of longitudinal sections of the PBS-treated tumors shows nerve expansion, intraneural inflammation, and hypercellularity, with tumor infiltrating and diffusing into the nerve bundles and forming clusters. (B) H&E staining of longitudinal sections of the AAV-merlin-treated tumors shows resolution of the tumor with some atypical cells remaining and a very mild hypercellularity still present. (C) Ki67 staining of longitudinal sections of PBS-treated tumors shows excessive proliferation of cells intraneurally, as well as perineurally. (D) Ki67 staining of longitudinal sections of the AAV-merlin-treated tumors shows resolution of cell proliferation with some lymphocytes present. SOX10 and S100 staining of longitudinal sections of (E and G) the untreated tumors shows a massively expanding nerve and an intraneural tumor that is displacing axons peripherally; rare scattered positive SOX10- and S100-stained cells are visible, but much of the tumor is dedifferentiated (negative staining). (F and H) SOX10 and S100 staining of longitudinal sections of the PBS-treated tumors shows extensive disruption of nerve fibers, while AAV-merlin-treated tumors show a normal-appearing nerve with intact architecture and tightly packed myelinated axons running longitudinally in most parts of the nerve; a small perineural area of hypercellularity might potentially constitute some remnants of the tumor; microscopic intraneural nodules of remnant tumor displacing axons are seen with S100, but not SOX10 staining.

Fig 3: Neuropathology of normal nerve and SC-null-FC schwannomaEstablishment of schwannoma tumor model via implantation of immortalized SC-null-FC cells directly into the sciatic nerve of immunodeficient mice with neuropathologic evaluation. (A) H&E staining of longitudinal sections of naive nerve, and (B) nerve post implantation (14 weeks) of SC-null-FC schwannoma cells. (C) In naive nerve, we detected no KI67-positive cells, (D) while many Ki67-positive SC-null-FC cells were detected in the schwannoma. (B and F) As compared with the naive nerve, the tumor-bearing nerve also exhibited disrupted architecture caused by proliferating tumor cells growing and displacing the few remaining myelinated axons (S100 positive). (E) Expression of Schwann cell marker SOX10 was detected in the normal nerve and (H) in the implanted SC-null-FC schwannoma cells.

Fig 4: In vitro analysis of functional NT-3 mRNA delivery by ExoNT-3. a Schematic illustration of the process of NT-3 mRNA delivery by the exosomes into SCs, which then translated into functional protein. b Fluorescence confocal microscopy images exhibit the endocytosis of the exosomes by SCs. The intracellular distribution of the exosomes were tracked by using DiR label. S100 was used to label SCs and Hoechst was used to counterstain nuclei. PBS was cocultured with SCs as the negative comparison. c Representative western blotting of NT-3 protein expressing in SCs. d qPCR analysis of NT-3 mRNA expression level in SCs. e ELISA was performed to test the secretion of NT-3 in SCs. Data are presented as mean ± SEM in 3 different experiments, *P < 0.05 by one-way ANOVA