Earliest cells of neural lineage express pluripotency and early neural genes. However, conditions essential for propagating these cells are not known. In this study, we investigated several factors that would support and propagate embryonic stem cells (ES) derived early neural stem cells. RT-qPCR data revealed that PD325901 (MEK inhibitor), Leukemia inhibitory factor (LIF) and KN93 (CAMKII inhibitor) (henceforth referred as PLK media) upregulated expression of early neural genes Sox1 and Pax6

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... ES cells, while the expression of pluripotency genes Oct4, Sox2 and Nanog remained on par with the ES cells cultured in ES media. On repeated passaging in PLK medium, expression of Sox1 and Pax6 increased gradually while expression of pluripotency genes remained constant. Moreover, even after several passages the PLK cultured cells were pluripotent, as confirmed by embryoid body (EB) mediated assay. To best of our knowledge, ours is the first group to report this unique combination of factors that potentially upregulated early neural genes while maintaining pluripotency. We feel it is appropriate to call the newly isolated cells "pro-neurogenic ES cells" (pnESC) and not primitive neural stem cells (pNSCs) since they retained pluripotency while pNSCs are not pluripotent.