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. Overall design: Whole genome bisulfite sequencing analysis of primed and naïve hESCs induced and maintained under alternative conditions