Reprogramming Human Fibroblasts to Pluripotency Using Modified mRNA The authors describe a stepwise protocol for the generation of modified mRNA-derived induced pluripotent stem cells from primary human fibroblasts, focusing on the critical parameters including medium choice, quality control, and optimization steps needed for synthesizing modified mRNAs encoding reprogramming factors and introducing these into cells over the course of 2-3 weeks to ensure successful reprogramming. [Nat Protoc] Abstract PML Bodies Provides an Important Platform for the Maintenance of Telomeric Chromatin Integrity in Embryonic Stem Cells Investigators demonstrated that α-thalassemia mental retardation X-linked and histone H3.3 co-localize with the telomeric DNA and associated proteins within the promyelocytic leukemia (PML) bodies in mouse embryonic stem cells. [Nucleic Acids Res] Full Article Induction of Pluripotent Stem Cells from Primordial Germ Cells by Single Reprogramming Factors The expression of reprogramming factors in primordial germ cells (PGCs) was analyzed. PGCs expressed Oct3/4, Sox2, and c-Myc but not Klf4. However, Klf2, Klf5, Essrb, or Essrg, which were expressed in PGCs, could compensate for Klf4 during somatic cell reprograming. [Stem Cells] Abstract Insulin Inhibits Cardiac Mesoderm, Not Mesendoderm, Formation During Cardiac Differentiation of Human Pluripotent Stem Cells and Modulation of Canonical Wnt Signaling Can Rescue This Inhibition The advent of human pluripotent stem cell technology and robust cardiac differentiation methods affords a unique opportunity to monitor the full course of cardiac induction in vitro. Investigators showed that stage-specific activation of insulin signaling strongly inhibited cardiac differentiation during a monolayer-based differentiation protocol that used transforming growth factor ß superfamily ligands to generate cardiomyocytes. [Stem Cells] Abstract Myoblasts and Embryonic Stem Cells Differentially Engraft in a Mouse Model of Genetic Dilated Cardiomyopathy The functional and architectural benefits of embryonic stem cells (ESC) and myoblasts (Mb) transplantations into infarcted myocardium have been investigated extensively. Scientists report that engrafted differentiated cells were consistently detected in myocardia of mice receiving Mb, whereas few or no cells were detected in the hearts of mice receiving ESC, except in two cases where teratomas were formed. [Mol Ther] Abstract Proliferation Rate of Somatic Cells Affects Reprogramming Efficiency The discovery of induced pluripotent stem (iPS) cells provides not only new approaches for cell replacement therapy, but also new ways for drug screening. However, the undefined mechanism and relatively low efficiency of reprogramming have limited the application of iPS cells. In an attempt to further optimize the reprogramming condition, scientists unexpectedly observed that removing c-Myc from the Oct-4, Sox-2, Klf-4, and c-Myc combination greatly enhanced the generation of iPS cells. [J Biol Chem] Abstract Efficient Derivation of Lateral Plate and Paraxial Mesoderm Subtypes from Human Embryonic Stem Cells through GSKi-Mediated Differentiation Scientists demonstrated that inhibition of glycogen synthase kinase-3 (GSK-3) is an essential first step towards efficient generation of the mesoderm. Under chemically defined conditions without additional growth factors/cytokines, short-term GSKi (GSK inhibitor) treatment effectively drives differentiation of human embryonic stem cells into the primitive streak, which can potentially commit towards the mesoderm when further supplemented with BMP4. [Stem Cells Dev] Abstract Differentiation of Human Embryonic Stem Cells into Cells with Corneal Keratocyte Phenotype Investigators sought to identify conditions inducing differentiation of pluripotent human embryonic stem (hES) cells to the keratocyte lineage. Neural differentiation of hES cell line WA01(H1) was induced by co-culture with mouse PA6 fibroblasts. [PLoS One] Full Article Demarcation of Stable Subpopulations within the Pluripotent hESC Compartment Human embryonic stem cells (hESCs) express REX1 transcripts but the distribution and properties of REX1 expressing cells have yet to be described. To address these questions, researchers used gene targeting in human ESCs to insert the fluorescent protein Venus and an antibiotic selection marker under the control of the endogenous REX1 transcription regulatory elements, generating a sensitive, selectable reporter of pluripotency. [PLoS One] Full Article Discovery of Pluripotency Associated MicroRNAs in Rabbit Preimplantation Embryos and Embryonic Stem-Like Cells Increasing experimental evidence implies an important regulatory role of microRNAs (miRNAs) during embryonic development and in embryonic stem cell biology. In the current study, scientists described and analyzed the expression profile of pluripotency-associated miRNAs in rabbit embryos and embryonic stem-like cells. [Reproduction] Abstract Modeling Human Protein Aggregation Cardiomyopathy Using Murine Induced Pluripotent Stem Cells To determine whether induced pluripotent stem cell (iPSC)-derived cardiomyocytes, a new experimental approach for human disease modeling, would be relevant to aggregation-prone disorders, researchers decided to exploit the existing transgenic mouse model to derive iPSCs from tail tip fibroblasts. Several iPSC lines were generated from transgenic (TG) and non-TG mice and validated for pluripotency. [Stem Cells Transl Med] Abstract |