Auxetic Nuclei in Embryonic Stem Cells Exiting Pluripotency It has been hypothesized that, before irreversibly committing, embryonic stem cells (ESCs) pass through at least one metastable transition state. This transition would represent a gateway for differentiation and reprogramming of somatic cells. Scientists showed that during the transition, the nuclei of ESCs are auxetic: they exhibit a cross-sectional expansion when stretched and a cross-sectional contraction when compressed, and their stiffness increases under compression. [Nat Mater] Abstract | Press Release JMJD5 Regulates Cell Cycle and Pluripotency in Human Embryonic Stem Cells Researchers identified JMJD5, a Jumonji C domain containing protein that, when depleted in human embryonic stem cells, causes the accumulation of cells in G1 phase, loss of pluripotency and subsequent differentiation into multiple lineages, most prominently ectoderm and trophectoderm. [Stem Cells] Abstract Parthenogenetic Embryonic Stem Cells Are an Effective Cell Source for Therapeutic Liver Repopulation Investigators determined whether parthenogenetic embryonic stem cell derivatives are effective in rescuing mice with lethal liver failure due to deficiency of fumarylacetoacetate hydrolase. [Stem Cells] Abstract Switching between Self-Renewal and Lineage Commitment of Human Induced Pluripotent Stem Cells via Cell-Substrate and Cell-Cell Interactions on a Dendrimer-Immobilized Surface Understanding mechanisms that govern cell fate determination of human induced pluripotent stem cells (hiPSCs) could assist in maintenance of the undifferentiated state during cell expansion. Investigators used polyamidoamine dendrimer surfaces with first-generation, third-generation and fifth-generation of dendron structure in cultures of hiPSCs with SNL feeder cells. [Biomaterials] Abstract Reprogramming of the Chick Retinal Pigmented Epithelium after Retinal Injury Researchers investigated the expression of pluripotency inducing factors in the retinal pigmented epithelium after retinectomy (injury) and during transdifferentiation in the presence of fibroblast growth factor 2. [BMC Biol] Abstract | Full Article Reactive Oxygen Species Regulate the Quiescence of CD34-Positive Cells Derived from Human Embryonic Stem Cells Few studies have examined the generation and function of reactive oxygen species (ROS) in human embryonic vascular development. The sources of ROS and their roles in the vascular differentiation of human embryonic stem cells were investigated. [Cardiovasc Res] Abstract Intracytoplasmic Sperm Injection Using DNA-Fragmented Sperm in Mice Negatively Affects Embryo-Derived Embryonic Stem Cells, Reduces the Fertility of Male Offspring and Induces Heritable Changes in Epialleles Investigators examined whether embryonic stem cells derived from DNA-fragmented sperm (DFS)-intracytoplasmic sperm injection (ICSI) embryos reflect the abnormalities observed in the DFS-ICSI progeny, the effect of DFS-ICSI on male fertility and whether DFS-ICSI induces epigenetic changes that lead to a modified heritable phenotype. [PLoS One] Full Article SIRT1 Is Necessary for Proficient Telomere Elongation and Genomic Stability of Induced Pluripotent Stem Cells Because telomere elongation is an induced pluripotent stem cell (iPSC) hallmark, scientists set out to study the role of SIRT1 in pluripotency in the setting of murine embryonic fibroblasts reprogramming into iPSCs. They found that SIRT1 is required for efficient postreprogramming telomere elongation, and that this effect is mediated by a c-MYC-dependent regulation of the mTert gene. [Stem Cell Rep] Full Article | Press Release |