Efficient derivation of extended pluripotent stem cells from NOD-scid Il2rg-/- mice

Attempts for deriving extended pluripotent stem cells from common marmoset embryonic stem cells

Extended pluripotent stem cells (EPSCs) derived from mice and humans showed an enhanced potential for chimeric formation. By exploiting transcriptomic approaches, we assessed the differences in gene expression profile between extended EPSCs derived from mice and humans, and those newly derived from the common marmoset (marmoset; Callithrix jacchus). Although the marmoset EPSC-like cells displayed a unique colony morphology distinct from murine and human EPSCs, they displayed a pluripotent state akin to embryonic stem cells (ESCs), as confirmed by gene expression and immunocytochemical analyses of pluripotency markers and three-germ-layer differentiation assay. Importantly, the marmoset EPSC-like cells showed interspecies chimeric contribution to mouse embryos, such as E6.5 blastocysts in vitro and E6.5 epiblasts in vivo in mouse development. Also, we discovered that the perturbation of gene expression of the marmoset EPSC-like cells from the original ESCs resembled that of human EPSCs. Taken together, our multiple analyses evaluated the efficacy of the method for the derivation of marmoset EPSCs.

Comparative functional genomics identifies unique molecular features of EPSCs

The authors provide a comprehensive resource on proteomics, transcriptomic, and epigenetic level details of EPSCs to shed light on possible molecular pathways regulating their expanded pluripotency potential.

Extended pluripotent or expanded potential stem cells (EPSCs) possess superior developmental potential to embryonic stem cells (ESCs). However, the molecular underpinning of EPSC maintenance in vitro is not well defined. We comparatively studied transcriptome, chromatin accessibility, active histone modification marks, and relative proteomes of ESCs and the two well-established EPSC lines to probe the molecular foundation underlying EPSC developmental potential. Despite some overlapping transcriptomic and chromatin accessibility features, we defined sets of molecular signatures that distinguish EPSCs from ESCs in transcriptional and translational regulation as well as metabolic control. Interestingly, EPSCs show similar reliance on pluripotency factors Oct4, Sox2, and Nanog for self-renewal as ESCs. Our study provides a rich resource for dissecting the regulatory network that governs the developmental potency of EPSCs and exploring alternative strategies to capture totipotent stem cells in culture.

Chemically defined and xeno-free culture condition for human extended pluripotent stem cells

Extended pluripotent stem (EPS) cells have shown great applicative potentials in generating synthetic embryos, directed differentiation and disease modeling. However, the lack of a xeno-free culture condition has significantly limited their applications. Here, we report a chemically defined and xeno-free culture system for culturing and deriving human EPS cells in vitro. Xeno-free human EPS cells can be long-term and genetically stably maintained in vitro, as well as preserve their embryonic and extraembryonic developmental potentials. Furthermore, the xeno-free culturing system also permits efficient derivation of human EPS cells from human fibroblast through reprogramming. Our study could have broad utility in future applications of human EPS cells in biomedicine.

The applications of human extended pluripotent stem cells (which can form both embryonic and extraembryonic lineages) demand a xeno-free culture condition; here, the authors provide a chemically defined and xeno-free culture system to do so.

Epigenetic Regulation of Transition Among Different Pluripotent States: Concise Review

The extraordinary progress of pluripotent stem cell research provides a revolutionary avenue to understand mammalian early embryonic development. Besides well-established conventional mouse and human embryonic stem cells, the discoveries of naive state human stem cell, two-cell-like cell, and the newly defined "extended pluripotent" stem cell and "expanded potential" stem cell with bidirectional chimeric ability have greatly broadened the horizons of more pluripotent states recaptured and maintained in dish, infinitely approaching the totipotent blastomere state. Although all these pluripotent cell types can self-renew and have the ability to differentiate into all the three germ layers, accumulating evidence suggests that these pluripotent states display distinct epigenetic characters. More strikingly, epigenetic reprogramming, including DNA methylation, histone modification, and chromatin remodeling, is required to reset the cell fate commitment, suggesting that epigenetic mechanisms may play an active and important role in the maintenance and transition among these pluripotent states. Here, we have reviewed studies on various pluripotent states, with a highlight on the epigenetic regulation during the interconversion. Stem Cells 2019;37:1372-1380.