Induction of neural differentiation by the transcription factor neuroD2.

Pro-neural basic helix loop helix (bHLH) transcription factors are involved in many aspects of normal neuronal development, and over-expression of genes for several of these factors has been shown to induce aspects of neuronal differentiation in cell lines and stem cells. Here we show that over-expression of NeuroD2 (ND2), Neurogenin1 and 2 leads to morphological differentiation of N18-RE-105 neuroblastoma cells and increased expression of synaptic proteins. Particularly ND2 induced neurite formation and increases in the expression of synaptic proteins such as synaptotagmin, that is not expressed normally in this cell type, as well as the redistribution of another synaptic protein, SNAP25, to a cell membrane location. Infection of human neural progenitor cells using adeno associated viral (AAV) vectors also promoted neuronal differentiation. Over-expressing cells demonstrated a significant increase in the neuron specific form of tubulin as well as increased expression of synaptotagmin. Genetic modification of neural progenitor cell with bHLH factors such as ND2 may be a viable strategy to enhance differentiation of these cells into replacement neurons for human disease.