Direct Reprogramming of Mouse and Human Fibroblasts into Multipotent Neural Stem Cells with a Single Factor

Abstract

SUMMARY The generation of induced pluripotent stem (iPS) cells and induced neuronal (iN) cells from somatic cells provides new avenues for basic research and potential transplantation therapies for neurological diseases. However, clinical applications must consider the risk of tumor formation by iPS cells and the inability of iN cells to self-renew in culture. Here we report the generation of induced neural stem cells (iNSCs) from mouse and human fibroblasts by direct reprogramming with a single factor, Sox2. iNSCs express NSC markers and resemble wild-type NSCs in their morphology, self-renewal, ability to form neurospheres, and gene expression profiles. Cloned iNSCs differentiate into several types of mature neurons, as well as astrocytes and oligodendrocytes, indicating multipotency. Implanted iNSCs can survive and integrate in mouse brains and, unlike iPS cell-derived NSCs, do not generate tumors. Thus, self-renewable and multipotent iNSCs without tumorigenic potential can be generated directly from fibroblasts by reprogramming.

SOX2 primes the epigenetic landscape in neural precursors enabling proper gene activation during hippocampal neurogenesis

“…Although SOX2 is arguably a cornerstone of neural stem cell biology (54,55) and plays an essential role in neurogenesis in the developing and adult brain (13), the mechanisms by which SOX2 regulates neuronal differentiation have remained unclear. In our previous study focusing on the LIN28 gene, which is fully active in NPCs, we found that SOX2 promotes an open chromatin state at the promoter (H3K9ac mark) through recruitment of the TRRAP/GCN5 complex (56).…”

“…Differentiation of neural progenitors is accompanied by an epigenetic switch characterized by a decrease of H3K27me3 and a gain of H3K4me3 at the promoters of proneural genes (6). Exogenous SOX2 expression previously was shown to be sufficient to reprogram fibroblasts into multipotent neural stem cells (NSCs) (55) or, in combination with Mash1, to reprogram human brain pericytes into neuronal cells (58). These findings suggested that SOX2 plays a key role in the epigenetic control of the neurogenic program, cooperating with the differentiation capacities of neurogenic factors.…”

Specification of functional neurons and glia from human pluripotent stem cells

“…Transdifferentiation from other type of somatic cells into functional neurons has allowed the generation of mature neurons in a relatively shorter period, which seems to be an ideal source of cells for transplantation, nevertheless, the efficiency of transdifferentiation is low, and the iNs are not expandable for large quantity. Alternative procedures that convert other type of somatic cells into expandable neural stem cells are also under extensive exploration (Kim et al, 2011;Han et al, 2012;Lujan et al, 2012;Ring et al, 2012;Sheng et al, 2012;Thier et al, 2012). In contrast to the iNs, the induced neural stem cells (iNSCs) are capable to proliferate, thus allow yield of larger quantity of cells through selectively amplification of the induced neural stem cells.…”

Direct lineage conversion: induced neuronal cells and induced neural stem cells

“…A recent report demonstrated the generation of iNS cells from mouse and human fibroblasts by direct reprogramming with a single factor, Sox2 (Ring et al, 2012). The derived NSC-like cells expressed Sox2, Nestin, Sox1, and Zbtb16 but did not express pluripotency-related genes such as Oct4, Nanog, and Zfp42; further, these cells can survive, integrate, and differentiate in vivo and do not generate tumors.…”