BackgroundThalassemia is the most common genetic disease worldwide; those with severe disease require lifelong blood transfusion and iron chelation therapy. The definitive cure for thalassemia is allogeneic hematopoietic stem cell transplantation, which is limited due to lack of HLA-matched donors and the risk of post-transplant complications. Induced pluripotent stem cell (iPSC) technology offers prospects for autologous cell-based therapy which could avoid the immunological problems. We now report genetic correction of the beta hemoglobin (HBB) gene in iPSCs derived from a patient with a double heterozygote for hemoglobin E and β-thalassemia (HbE/β-thalassemia), the most common thalassemia syndrome in Thailand and Southeast Asia.MethodsWe used the CRISPR/Cas9 system to target the hemoglobin E mutation from one allele of the HBB gene by homology-directed repair with a single-stranded DNA oligonucleotide template. DNA sequences of the corrected iPSCs were validated by Sanger sequencing. The corrected clones were differentiated into hematopoietic progenitor and erythroid cells to confirm their multilineage differentiation potential and hemoglobin expression.ResultsThe hemoglobin E mutation of HbE/β-thalassemia iPSCs was seamlessly corrected by the CRISPR/Cas9 system. The corrected clones were differentiated into hematopoietic progenitor cells under feeder-free and OP9 coculture systems. These progenitor cells were further expanded in erythroid liquid culture system and developed into erythroid cells that expressed mature HBB gene and HBB protein.ConclusionsOur study provides a strategy to correct hemoglobin E mutation in one step and these corrected iPSCs can be differentiated into hematopoietic stem cells to be used for autologous transplantation in patients with HbE/β-thalassemia in the future.Electronic supplementary materialThe online version of this article (10.1186/s13287-018-0779-3) contains supplementary material, which is available to authorized users.

Somatic cell reprogramming has generated enormous interest after the first report by Yamanaka and his coworkers in 2006 on the generation of induced pluripotent stem cells (iPSCs) from mouse fibroblasts. Here we report the generation of stable iPSCs from mouse fibroblasts by recombinant protein transduction (Klf4, Oct4, Sox2, and c-Myc), a procedure designed to circumvent the risks caused by integration of exogenous sequences in the target cell genome associated with gene delivery systems. The recombinant proteins were fused in the frame to the glutathione-S-transferase tag for affinity purification and to the transactivator transcription-nuclear localization signal polypeptide to facilitate membrane penetration and nuclear localization. We performed the reprogramming procedure on embryonic fibroblasts from inbred (C57BL6) and outbred (ICR) mouse strains. The cells were treated with purified proteins four times, at 48-h intervals, and cultured on mitomycin C treated mouse embryonic fibroblast (MEF) cells in complete embryonic stem cell (ESC) medium until colonies formed. The iPSCs generated from the outbred fibroblasts exhibited similar morphology and growth properties to ESCs and were sustained in an undifferentiated state for more than 20 passages. The cells were checked for pluripotency-related markers (Oct4, Sox2, Klf4, cMyc, Nanog) by immunocytochemistry and by reverse transcription-polymerase chain reaction. The protein iPSCs (piPSCs) formed embryoid bodies and subsequently differentiated towards all three germ layer lineages. Importantly, the piPSCs could incorporate into the blastocyst and led to variable degrees of chimerism in newborn mice. These data show that recombinant purified cell-penetrating proteins are capable of reprogramming MEFs to iPSCs. We also demonstrated that the cells of the generated cell line satisfied all the requirements of bona fide mouse ESCs: form round colonies with defined boundaries; have a tendency to attach together with high nuclear/cytoplasmic ratio; express key pluripotency markers; and are capable of in vitro differentiation into ecto-, endo-, and mesoderm, and in vivo chimera formation.

Incurable neurological disorders such as Parkinson’s disease (PD), Huntington’s disease (HD), and Alzheimer’s disease (AD) are very common and can be life-threatening because of their progressive disease symptoms with limited treatment options. To provide an alternative renewable cell source for cell-based transplantation and as study models for neurological diseases, we generated induced pluripotent stem cells (iPSCs) from human dermal fibroblasts (HDFs) and then differentiated them into neural progenitor cells (NPCs) and mature neurons by dual SMAD signaling inhibitors. Reprogramming efficiency was improved by supplementing the histone deacethylase inhibitor, valproic acid (VPA), and inhibitor of p160-Rho associated coiled-coil kinase (ROCK), Y-27632, after retroviral transduction. We obtained a number of iPS colonies that shared similar characteristics with human embryonic stem cells in terms of their morphology, cell surface antigens, pluripotency-associated gene and protein expressions as well as their in vitro and in vivo differentiation potentials. After treatment with Noggin and SB431542, inhibitors of the SMAD signaling pathway, HDF-iPSCs demonstrated rapid and efficient differentiation into neural lineages. Six days after neural induction, neuroepithelial cells (NEPCs) were observed in the adherent monolayer culture, which had the ability to differentiate further into NPCs and neurons, as characterized by their morphology and the expression of neuron-specific transcripts and proteins. We propose that our study may be applied to generate neurological disease patient-specific iPSCs allowing better understanding of disease pathogenesis and drug sensitivity assays.

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Embryonic stem cell (ESC)-derived cardiomyocytes are a promising cell source for the screening for potential cytoprotective molecules against ischemia/reperfusion injury, however, little is known on their behavior in hypoxia/reoxygenation conditions. Here we tested the cytoprotective effect of the NO-donor SNAP and its downstream cellular pathway. Mouse ESC-derived cardiomyocytes were subjected to 150-min simulated ischemia (SI) followed by 120-min reoxygenation or corresponding non-ischemic conditions. The following treatments were applied during SI or normoxia: the NO-donor S-Nitroso-N-acetyl-D,L-penicillamine (SNAP), the protein kinase G (PKG) inhibitor, the KATP channel blocker glibenclamide, the particulate guanylate cyclase activator brain type natriuretic peptide (BNP), and a non-specific NO synthase inhibitor (N-Nitro-L-arginine, L-NNA) alone or in different combinations. Viability of cells was assayed by propidium iodide staining. SNAP attenuated SI-induced cell death in a concentration-dependent manner, and this protection was attenuated by inhibition of either PKG or KATP channels. However, SI-induced cell death was not affected by BNP or by L-NNA. We conclude that SNAP protects mESC-derived cardiomyocytes against SI/R injury and that soluble guanylate-cyclase, PKG, and KATP channels play a role in the downstream pathway of SNAP-induced cytoprotection. The present mESC-derived cardiomyocyte based screening platform is a useful tool for discovery of cytoprotective molecules.

To cite this version:Sasitorntime of EB adherence to gelatin-coated dishes, and rotation speed for optimal EB formation and cardiac differentiation were investigated. Using 3x10 5 cells/ml, 10 rpm rotary speed and plating of EBs onto gelatin-coated surfaces three days after culture, were the best parameters for optimal size and EB quality on consequent cardiac differentiation. These optimized parameters enrich cardiac differentiation in ES cells when using the STLV method.

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Platelet transfusion has been widely used to prevent and treat life-threatening thrombocytopenia; however, preparation of a unit of concentrated platelet for transfusion requires at least 4-6 units of whole blood. At present, a platelet unit from a single donor can be prepared using apheresis, but lack of donors is still a major problem. Several approaches to produce platelets from other sources, such as haematopoietic stem cells and pluripotent stem cells, have been attempted but the system is extremely complicated, time-consuming and expensive. We now report a novel and simpler technology to obtain platelets using transdifferentiation of human bone marrow erythroblasts to megakaryocytes with overexpression of the FLI1 and ERG genes. The obtained transdifferentiated erythroblasts (both from CD71+ and GPA+ erythroblast subpopulations) exhibit typical features of megakaryocytes including morphology, expression of specific genes (cMPL and TUBB1) and a marker protein (CD41). They also have the ability to generate megakaryocytic CFU in culture and produce functional platelets, which aggregate with normal human platelets to form a normal-looking clot. Overexpression of FLI1 and ERG genes is sufficient to transdifferentiate erythroblasts to megakaryocytes that can produce functional platelets.