Formative transition of human naïve pluripotent stem cells

Human naïve pluripotent stem cells (PSC) share features with pre-implantation epiblast. They thus provide an unmatched opportunity for characterising the developmental programme of pluripotency in Homo sapiens. Here we confirm that naïve PSC do not respond directly to germ layer induction, but must first acquire competence. Capacitation for multi-lineage differentiation occurs without exogenous growth factor stimulation and is facilitated by inhibition of Wnt signalling. Whole transcriptome profiling during this formative transition highlights dynamic changes in gene expression, affecting many cellular properties, including metabolism and epithelialisation. Notably, naïve pluripotency factors are exchanged for post-implantation factors, but competent cells remain devoid of lineage primed transcription. The gradual pace of transition for human naïve PSC is consistent with the timespan of primate development from blastocyst to gastrulation. Transcriptome trajectory during in vitro capacitation of human naïve cells tracks the progression of epiblast during embryogenesis in Macaca fascicularis, but shows greater divergence from mouse development. Thus the formative transition of naïve PSC in a simple culture system may recapitulate essential and specific features of pluripotency dynamics during an inaccessible period of human embryogenesis. 2 lines of human naïve pluripotent stem cells (embryo-derived HNES1 and chemically reset cR-H9-EOS) were cultured in N2B27 and 2uM XAV939 for 10 days. After that the cells were split into two conditions: N2B27 + 2uM XAV939 + 3ng/ml Activin A + 10ng/ml FGF2 (XAF), or E8 medium, for extended maintenance. The experiment was performed in biological triplicates for each cell line. RNAseq was performed with the cells on day 0, 1, 2, 3, 7, 10, when the cells were cultured in XAV939; and one time point after transfer to maintenance conditions, at not less than 22 days of culture from the start of the experiment. Conventional hES cell line H9-EOS, which was a parental line for the chemically reset cR-H9-EOS was used as a control (in biological triplicate).