Esrrb Is a Pivotal Target of the Gsk3/Tcf3 Axis Regulating Embryonic Stem Cell Self-Renewal

Summary

Inhibition of glycogen synthase kinase-3 (Gsk3) supports mouse embryonic stem cells (ESCs) by modulating Tcf3, but the critical targets downstream of Tcf3 are unclear. We analyzed the intersection between genome localization and transcriptome data sets to identify genes repressed by Tcf3. Among these, manipulations of Esrrb gave distinctive phenotypes in functional assays. Knockdown and knockout eliminated response to Gsk3 inhibition, causing extinction of pluripotency markers and loss of colony forming capability. Conversely, forced expression phenocopied Gsk3 inhibition or Tcf3 deletion by suppressing differentiation and sustaining self-renewal. Thus the nuclear receptor Esrrb is necessary and sufficient to mediate self-renewal downstream of Gsk3 inhibition. Leukaemia inhibitory factor (LIF) regulates ESCs through Stat3, independently of Gsk3 inhibition. Consistent with parallel operation, ESCs in LIF accommodated Esrrb deletion and remained pluripotent. These findings highlight a key role for Esrrb in regulating the naive pluripotent state and illustrate compensation among the core pluripotency factors.

Highlights

► Esrrb is the principal target of Tcf3 repression in the pluripotency network ► Esrrb is essential for self-renewal downstream of Gsk3 inhibition ► Esrrb potently suppresses differentiation and sustains ESC self-renewal ► Esrrb is a core pluripotency factor but can be compensated by LIF/Stat3

Abstract

Inhibition of glycogen synthase kinase 3 keeps embryonic stem cells in a naïve ground state. Surprisingly this effect is mediated mainly by upregulating expression of a single transcription factor Esrrb. Esrrb function can be compensated by independent activation of Stat3, however, demonstrating the plasticity of the core network underpinning pluripotency.