Gene expression of induced neural stem cells

Neural stem cell (NSC) transplantation replaces damaged brain cells and provides disease-modifying effects in many neurological disorders. However, there has been no efficient way to obtain autologous NSCs in patients. Given that ectopic factors can reprogram somatic cells to be pluripotent, we attempted to generate human NSC-like cells by reprograming human fibroblasts. Fibroblasts were transfected with NSC line-derived cellular extracts and grown in neurosphere culture conditions. The cells were then analyzed for NSC characteristics, including neurosphere formation, gene expression patterns, and ability to differentiate. The obtained induced neurosphere-like cells (iNS), which formed daughter neurospheres after serial passaging, expressed neural stem cell markers, and had demethylated SOX2 regulatory regions, all characteristics of human NSCs. The iNS had gene expression patterns that were a combination of the patterns of NSCs and fibroblasts, but they could be differentiated to express neuroglial markers and neuronal sodium channels. These results show for the first time that iNS can be directly generated from human fibroblasts. Further studies on their application in neurological diseases are warranted. We generated induced neural stem cells (iNS) and compared the gene expressions with control cells, which included primary human dermal fibroblast cultured in DMEM media (FB), primary human dermal fibroblast cultured in neurosphere-forming condition (FB_con), and neural stem cell line (F3). The four cell lines (iNS, FB, FB_con, and F3) showed different gene expression patterns. In detail, RNA was isolated using Trizol (Invitrogen) according to the manufacturer's instructions, and was labeled and hybridized to an Affimetrix GeneChip human gene 1.0 ST array (Affimetrix, Santa Clara, CA, USA) as described according to the manufacturer’s instructions. Data were analyzed using Expression Console software version 1.1 (Affimetrix), in which gene expression ratios were normalized by Robust Multichip Analysis according to the manufacturer’s protocol.