Probing the signaling requirements for naïve human pluripotency by high-throughput chemical screening [WGBS]

Background: Naïve human embryonic stem cells (hESCs) have been isolated that more closely resemble the pre-implantation epiblast compared to conventional “primed” hESCs, but the signaling principles underlying these discrete stem cell states remain incompletely understood. Methods:Here we performed high-throughput screening using a library of >3,000 well-annotated compounds to identify essential signaling requirements for naïve human pluripotency. Results:We report that MEK1/2 inhibitors can be replaced during maintenance of naïve human pluripotency by inhibitors targeting either upstream (FGFR, RAF1) or downstream (ERK1/2) kinases. Naïve hESCs maintained under these alternative conditions display elevated levels of ERK phosphorylation but retain genome-wide DNA hypomethylation and a transcriptional identity of the pre-implantation epiblast. In contrast, dual inhibition of MEK and ERK promotes efficient primed-to-naïve resetting in combination with PKC, ROCK, and TNKS inhibitors and Activin A. Conclusions: This work demonstrates that induction and maintenance of naïve human pluripotency are governed by distinct signaling requirements. Whole genome bisulfite sequencing analysis of primed and naïve hESCs induced and maintained under alternative conditions