ESC & iPSC News Volume 14.17 | May 8 2019

TOP STORY

Highly Efficient and Marker-Free Genome Editing of Human Pluripotent Stem Cells by CRISPR-Cas9 RNP and AAV6 Donor-Mediated Homologous Recombination

Researchers describe marker-free genome editing in human PSCs (hPSCs) using Cas9 ribonucleoproteins in combination with AAV6-mediated DNA repair template delivery. They report highly efficient and bi-allelic integration frequencies across multiple loci and hPSC lines, achieving mono-allelic editing frequencies of up to 94% at the HBB locus. [Cell Stem Cell] Abstract | Graphical Abstract

(Ranked by impact factor of the journal)

Cross-Regulation Between TDP-43 and Paraspeckles Promotes Pluripotency-Differentiation Transition

Investigators showed that the expression and activity of the RNA-binding protein TDP-43 and the long isoform of the lncRNA Neat1, the scaffold of the nuclear compartment “paraspeckles,” were reciprocal in pluripotent and differentiated cells because of their cross-regulation. In pluripotent cells, TDP-43 repressed the formation of paraspeckles by enhancing the polyadenylated short isoform of Neat1. [Mol Cell] Full Article | Graphical Abstract | Press Release

Generation of Hypoimmunogenic Human Pluripotent Stem Cells

The authors employed multiplex genome editing to specifically ablate the expression of the highly polymorphic HLA-A/-B/-C and HLA class II in human pluripotent stem cells. Furthermore, to prevent innate immune rejection and further suppress adaptive immune responses, they expressed the immunomodulatory factors PD-L1, HLA-G, and the macrophage “don’t-eat me” signal CD47 from the AAVS1 safe harbor locus. [Proc Natl Acad Sci USA] Abstract

Defining Reprogramming Checkpoints from Single-Cell Analyses of Induced Pluripotency

The researchers increased the efficiency with a combination of epigenomic modifiers and signaling molecules and profiled the transcriptomes of individual reprogramming cells. Contrary to the established temporal order, somatic gene inactivation and upregulation of cell cycle, epithelial, and early pluripotency genes could be triggered independently such that any combination of these events could occur in single cells. [Cell Rep] Full Article | Graphical Abstract

Zfp281 Shapes the Transcriptome of Trophoblast Stem Cells and Is Essential for Placental Development

Scientists conducted a forward genetic screen to identify regulators for extraembryonic development and identified Zfp281 as a key factor. Zfp281 overexpression in mouse ESCs facilitated the induction of trophoblast stem-like cells. Zfp281 was preferentially expressed in the undifferentiated trophoblast stem cell population in an FGF-dependent manner, and disruption of Zfp281 in mice caused severe defects in early placental development. [Cell Rep] Full Article | Graphical Abstract

Enhancer Chromatin and 3D Genome Architecture Changes from Naive to Primed Human Embryonic Stem Cell States

The 2iL/I/F enhancer repertoire occupied 9% of the genome, three times that of primed cells, and could exist in broad chromatin domains over 50 kb. Enhancer chromatin states were largely poised. 77% of 2iL/I/F enhancers were decommissioned in a stepwise manner as cells become primed. [Stem Cell Reports] Full Article | Graphical Abstract

Context-Dependent Impact of RAS Oncogene Expression on Cellular Reprogramming to Pluripotency

Scientists addressed the effect of expressing an active oncogene, RAS, on the process of reprogramming and found that, while combined expression with reprogramming factors enhanced dedifferentiation, expression within the context of neoplastic transformation impaired reprogramming. RAS induced expression changes that promoted loss of cell identity and acquisition of stemness in a paracrine manner and these changes resulted in reprogramming when combined with reprogramming factors. [Stem Cell Reports] Full Article | Graphical Abstract

Metabolomic and Transcriptional Analyses Reveal Atmospheric Oxygen During Human Induced Pluripotent Stem Cell Generation Impairs Metabolic Reprogramming

Metabolic analyses of iPSCs generated under either physiological (P-iPSC) or atmospheric (A-iPSC) oxygen conditions revealed they retained aspects of somatic cell metabolic memory and failed to regulate carbohydrate metabolism, with A-iPSCs acquiring different metabolic characteristics. A-iPSCs exhibited a higher mitochondrial membrane potential and were unable to modulate oxidative metabolism in response to oxygen challenge, contrasting with P-iPSCs. [Stem Cells] Abstract | Full Article

UM171 Expands Distinct Types of Myeloid and NK Progenitors from Human Pluripotent Stem Cells

Investigators explored the potential of the HSC agonist pyrimido-indole derivative UM171, to expand hematopoietic progenitors (HPs) derived from HPSCs in chemically defined conditions. They revealed that cultures of hPSC-HPs in HSC expansion conditions in the presence of UM171 predominantly expanded HPs with a unique CD34⁺CD41a^loCD45⁺ phenotype that were enriched in granulocytic progenitors. [Sci Rep] Full Article

Slc25a36 Modulates Pluripotency of Mouse Embryonic Stem Cells by Regulating Mitochondrial Function and Glutathione Level

The function of Slc25a36 was characterized as a maintenance factor of mouse ESC (mESC) pluripotency. Slc25a36 deficiency (via knockdown) was demonstrated to result in mitochondrial dysfunction, which induced the differentiation of mESCs. The expression of key pluripotency markers decreased, while that of key TE genes increased. [Biochem J] Abstract

Modelling the Neuropathology of Lysosomal Storage Disorders Through Disease-Specific Human Induced Pluripotent Stem Cells

Mucopolysaccharidosis II (MPS II)-patient derived iPSC lines were established and differentiated to neuronal lineage. The disease phenotype was confirmed by iduronate 2-sulphatase enzyme and glycosaminoglycan assay. MPS II neuronal precursor cells showed significantly decreased self-renewal capacity, while their cortical neuronal differentiation potential was not affected. [Exp Cell Res] Full Article

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Precision Matchmaking: Induced Pluripotent Stem Cells Meet Cardio-Oncology

The authors review the recent advances in preclinical cancer-related cardiotoxicity testing, focusing on new technologies, such as human induced pluripotent stem cell-derived cardiomyocytes and tissue engineering. They further discuss some of the limitations of these technologies and present future directions. [Stem Cells Transl Med] Full Article

Metabolism Is a Key Regulator of Induced Pluripotent Stem Cell Reprogramming

The significance of metabolites during the reprogramming process is central to further elucidating how iPSCs retain somatic cell characteristics and optimizing culture conditions to generate iPSC with physiological phenotypes to ensure their reliable use in basic research and clinical applications. Investigators integrate studies on iPSC reprogramming, memory retention and metabolism, and identify areas in which current knowledge is limited. [Stem Cells Int] Full Article

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uniQure Announces Featured Presentations of New Data on Spinocerebellar Ataxia Type 3

uniQure N.V. will present preclinical data on its gene therapy candidate, AMT-150, for the treatment of spinocerebellar ataxia 3. The abstract is entitled, “Development of an AAV-based microRNA Gene Therapy for Treating Spinocerebellar Ataxia Type 3.” [Press release from uniQure N.V. discussing research to be presented at the 2019 American Academy of Neurology (AAN) Annual Meeting, Philadelphia] Press Release

Gilead Sciences and Goldfinch Bio Announce Strategic Collaboration to Develop Novel Therapies for Kidney Disease

Gilead Sciences, Inc. announced a strategic collaboration to discover, develop and commercialize a pipeline of innovative therapeutics for diabetic kidney disease and certain orphan kidney diseases. [Gilead Sciences, Inc.] Press Release

BioTime Announces Issuance of US Patent for Method of Reducing Cavitation in Patients with Acute Spinal Cord Injury

BioTime, Inc. announced the issuance of a Notice of Allowance for a patent from the United States Patent and Trademark Office for United States Patent Application No. 15/156,316 for a method of reducing spinal cord injury (SCI)-induced parenchymal cavitation in patients that have suffered an acute SCI. [BioTime, Inc.] Press Release

Black Academics Publish One-Fifth of South Africa’s Research

The proportion of scientific articles published by academics in South Africa who are black, colored or of Indian origin has risen almost tenfold since the end of apartheid, to about one-third, finds a report on scholarly publishing in the country. [Nature News] Editorial

White House to Convene Committee to Address Research Obstacles

The leaders of the White House Office of Science and Technology, National Institutes of Health, National Science Foundation, National Institute of Standards and Technology, and the Department of Energy’s science division have formed a committee “to address issues facing the US research community,” President Donald Trump’s administration announced. [The Scientist] Editorial

NEW The Business of Regenerative Medicine
July 15-16, 2019
Boston, Massachusetts, United States

Visit our events page to see a complete list of events in the community.

NEW Postdoctoral Fellow – iPSC Based Disease Modelling (The New York Stem Cell Foundation)

NEW Lab Manager – Chromatin’s Role in Pluripotency & Self-Renewal (Howard Hughes Medical Institute)

Scientist – Stem Cell Metabolism (STEMCELL Technologies Inc.)

Postdoctoral Associate – Stem Cell Differentiation in Immunology (University of Massachusetts Medical School)

Research Assistant – Stem Cells & Regenerative Medicine (Boston Children’s Hospital)

Postdoctoral Fellow – Pluripotent Stem Cells & Joint Tissue Development (Boston Children’s Hospital)

Postdoctoral Fellowship – iPSCs and Differentiated Neurons (Howard Hughes Medical Institute)

Postdoctoral Fellowship – Cell Fate and Cancer Initiation (University of Miami Miller School of Medicine)

Postdoctoral Position – Human Pluripotent Stem Cell Biology (Washington University School of Medicine)

Postdoctoral Positions – Epigenetics of Stem Cells, Development and Cancer (Albert Einstein College of Medicine)

Staff Scientist – Transcriptional Control in Development and Disease (Fred Hutchinson Cancer Research Center)

Postdoctoral Fellow Positions – Human iPSCs, Epigenetics, Hematopoietic Stem Cell Biology, and Blood Cancers (Nationwide Children’s Hospital & Ohio State University)

Director of Operations – Biotech Production (Cincinnati Children’s Hospital Medical Center)

Postdoctoral Fellow – Genetics and Epigenomics of iPSC Biology (Stanford University)

Assistant Associate Professor/Professor in Residence – Stem Cell Program (UC Davis)

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