GSK3α functions as a stemness checkpoint across multiple stem cell states

Mouse embryonic stem cells (ESCs) and epiblast stem cells (EpiSCs) represent the naïve and primed pluripotent states, respectively, each requiring distinct culture conditions. In this study, we show that BRD0705, a selective GSK3α inhibitor, significantly enhances the self-renewal of both ESCs and EpiSCs. When combined with IWR1, BRD0705 sustains long-term maintenance of ESCs in a naïve state and EpiSCs in a primed state, even preserving their unique identities under long-term co-culture. Single-cell RNA sequencing and histone mark profiling confirm that this regimen maintains distinct gene expression and epigenetic signatures corresponding to each pluripotent state. Importantly, unlike pan-GSK3 inhibitors CHIR-99021 (CHIR), BRD0705 acts independently of β-catenin signaling, unveiling a novel mechanism for supporting pluripotency. Finally, BRD0705/IWR1 also supports the maintenance of the formative pluripotent stem cells and neural stem cells. Collectively, we propose that GSK3α inhibition may preserve diverse stem cell states by insulating stem cells from differentiation cues and promoting their intrinsic self-renewal capacity. We believe our findings lay the foundation for universal stem cell culture methods with significant regenerative medicine applications.