Systematic Identification of Defined Conditions for Induction and Maintenance of Naive Human Pluripotency [expression]

Embryonic stem cells (ESCs) of mice and humans have distinct molecular and biological characteristics, raising the question whether an earlier ‘naive’ state of pluripotency may exist in humans. Here we took a systematic approach to identify small molecules that support autonomous self-renewal of naive human ESCs based on maintenance of endogenous OCT4 distal enhancer activity, a molecular signature of ground state pluripotency. Iterative chemical screening identified a combination of five kinase inhibitors that induces and maintains OCT4 distal enhancer activity when applied directly to conventional human ESCs. These inhibitors generate a homogeneous population of human pluripotent stem cells in which transcription factors associated with the ground state of pluripotency are highly upregulated. Comparison with previously reported naive human ESCs indicates that our kinase inhibitor cocktail captures a novel pluripotent state in humans that closely resembles mouse ESCs. Expression analysis was performed on two groups of human ESC samples: WIBR2 (P12 and P14), WIBR3 (P9) and WIN1 (P10) human ESCs derived in our optimized naive medium (5i/L/A or 6i/L/A, as indicated), and parental WIBR2 and WIBR3 human ESCs in primed human ESC medium.