Self-Renewal of Embryonic- Stem-Cell-Derived Progenitors by Organ-Matched Mesenchyme Researchers found that co-culture with organ-matched mesenchyme permits proliferation and self-renewal of progenitors, without differentiation, and enables an expansion of more than a million-fold for human endodermal cells with full retention of their developmental potential. [Nature] Abstract Esrrb Is a Pivotal Target of the Gsk3/Tcf3 Axis Regulating Embryonic Stem Cell Self- Renewal Inhibition of glycogen synthase kinase-3 (Gsk3) supports mouse embryonic stem cells by modulating Tcf3, but the critical targets downstream of Tcf3 are unclear. Researchers analyzed the intersection between genome localization and transcriptome data sets to identify genes repressed by Tcf3. [Cell Stem Cell] Abstract Altered Hematopoiesis in Trisomy 21 as Revealed through In Vitro Differentiation of Isogenic Human Pluripotent Cells Human trisomy 21 pluripotent cells of various origins, human embryonic stem, and induced pluripotent stem cells, were differentiated in vitro as a model to recapitulate the effects of trisomy on hematopoiesis. [Proc Natl Acad Sci USA] Abstract | Full Article Trisomy 21-Associated Defects in Human Primitive Hematopoiesis Revealed through Induced Pluripotent Stem Cells Researchers modeled Down syndrome (trisomy 21, T21) yolk sac hematopoiesis using human induced pluripotent stem cells (iPSCs). Blood progenitor populations generated from T21 iPSCs were present at normal frequency and proliferated normally. [Proc Natl Acad Sci USA] Abstract Development of a Novel Two- Dimensional Directed Differentiation System for Generation of Cardiomyocytes from Human Pluripotent Stem Cells Investigators developed a novel two dimensional stepwise differentiation system that generates a high yield of cardiomyocytes from human pluripotent stem cells without using special cytokines. [Int J Cardiol] Abstract Establishment of a Molecular Embryonic Stem Cell Developmental Toxicity Assay The mouse embryonic stem cell test (EST) is a ten-day screen for teratogenic potential developed to reduce animal use for embryotoxicity testing of chemicals. In this study, the authors used the cytotoxicity IC50 values and transcriptional expression changes as primary endpoints in a shorter four-day version of the EST, the molecular embryonic stem cell assay. [Toxicol Sci] Abstract γ-Secretase Inhibitors Prevent Overgrowth of Transplanted Neural Progenitors Derived from Human-Induced Pluripotent Stem Cells Researchers used γ-secretase inhibitors to dampen Notch signaling in human-induced pluripotent stem cell-derived neural progenitors before transplantation and examined the effects on the growth of proliferative grafts. [Stem Cells Dev] Abstract Over-Expression of Kir2.1 Channel in Embryonic Stem Cell-Derived Cardiomyocytes Attenuates Post-Transplantation Proarrhythmic Risk in Myocardial Infarction The authors investigated whether forced expression of Kir2.1-encoded inward rectifying K+ channels that are otherwise absent in embryonic stem cell-derived cardiomyocytes would attenuate their proarrhythmic risk after post-myocardial infarction transplantation. [Heart Rhythm] Abstract Nuclear Transferred Embryonic Stem Cell for Analysis of B1 B-Lymphocyte Development Scientists demonstrated that nuclear transferred embryonic stem cells can be established with high efficiency using innate-like B lymphocytes as donor cells. [Int Immunol] Abstract The KRAB-ZFP/KAP1 System Contributes to the Early Embryonic Establishment of Site-Specific DNA Methylation Patterns Maintained during Development Researchers demonstrated that the KRAB-ZFP-mediated recruitment of KAP1 to DNA in embryonic stem cells induces cytosine methylation. [Cell Rep] Abstract | Press Release | Graphical Abstract |