Unraveling hallmark suitability for staging pre- and post-implantation stem cell models

The advent of novel 2D and 3D models for human development, including trophoblast stem cells and blastoids, has expanded opportunities for investigating early developmental events, gradually illuminating the enigmatic realm of human development. While these innovations have ushered in new prospects, it has become essential to establish well-defined benchmarks for the cell sources of these models. We aimed to propose a comprehensive characterization of pluripotent and trophoblastic stem cell models by employing a combination of transcriptomic, proteomic, epigenetic, and metabolic approaches. Our findings reveal that extended pluripotent stem cells share many characteristics with primed pluripotent stem cells, with the exception of metabolic activity. Furthermore, our research demonstrates that DNA hypomethylation and high metabolic activity define trophoblast stem cells. These results underscore the necessity of considering multiple hallmarks of pluripotency rather than relying on a single criterion. Multiplying hallmarks alleviate stage-matching bias. [Display omitted] •Comparison of hTSCs, hTELCs, primed hPSCs, naive hPSCs, and hEPSCs•hEPSCs have DNAme levels and X activity similar to primed hPSCs•hEPSCs have a higher metabolic activity than hPSCs•hTSCs have the highest metabolic activity of all cell types measured Onfray et al. report the comparison of hTSCs, hTELCs, and primed, extended, and naive hPSCs by transcriptomics, proteomics, DNAme quantification, X, and metabolic activity. TELCs have features of trophectoderms, while TSCs represent post-implantation trophoblasts. hEPSCs are clearly primed cells but display a higher metabolic and clonogenic potential than regular primed PSCs.