mNgn2-induced neurons demonstrated elevated mRNA and protein levels of excitatory synaptic markers, relative to GFP-transduced NPCs. At 3 weeks of induction, mNgn2-induced neurons showed increased SYN1-puncta (relative to MAP2AB area; 1.9-fold, p < 0.05) (Fig. 4A and B) and SYN1 mRNA expression (2.3-fold, p < 0.001) (Fig. 4C). Neither vGLUT1 nor PSD95 puncta could be detected in our cultures, which lacked either mouse cortical neuron or human astrocyte co-culture. mNgn2-induced neurons demonstrated elevated vGLUT1 (4.5-fold, p < 0.001) and vGLUT2 (3.8-fold, p < 0.001) mRNA expression, but not increased PSD95, relative to GFP-transduced NPCs (Fig. 4C).
