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Induced pluripotent stem cell (iPSC)-based technologies offer an unprecedented opportunity to perform high-throughput screening of novel drugs for neurological and neurodegenerative diseases. Such screenings require a robust and scalable method for generating large numbers of mature,differentiated neuronal cells. Currently available methods based on differentiation of embryoid bodies (EBs) or directed differentiation of adherent culture systems are either expensive or are not scalable. We developed a protocol for large-scale generation of neuronal stem cells (NSCs)/early neural progenitor cells (eNPCs) and their differentiation into neurons. Our scalable protocol allows robust and cost-effective generation of NSCs/eNPCs from iPSCs. Following culture in neurobasal medium supplemented with B27 and BDNF,NSCs/eNPCs differentiate predominantly into vesicular glutamate transporter 1 (VGLUT1) positive neurons. Targeted mass spectrometry analysis demonstrates that iPSC-derived neurons express ligand-gated channels and other synaptic proteins and whole-cell patch-clamp experiments indicate that these channels are functional. The robust and cost-effective differentiation protocol described here for large-scale generation of NSCs/eNPCs and their differentiation into neurons paves the way for automated high-throughput screening of drugs for neurological and neurodegenerative diseases. View Publication

Huntington's disease (HD) is a fatal neurodegenerative disease,caused by expansion of polyglutamine repeats in the Huntingtin gene,with longer expansions leading to earlier ages of onset. The HD iPSC Consortium has recently reported a new in vitro model of HD based on the generation of induced pluripotent stem cells (iPSCs) from HD patients and controls. The current study has furthered the disease in a dish model of HD by generating new non-integrating HD and control iPSC lines. Both HD and control iPSC lines can be efficiently differentiated into neurons/glia; however,the HD-derived cells maintained a significantly greater number of nestin-expressing neural progenitor cells compared with control cells. This cell population showed enhanced vulnerability to brain-derived neurotrophic factor (BDNF) withdrawal in the juvenile-onset HD (JHD) lines,which appeared to be CAG repeat-dependent and mediated by the loss of signaling from the TrkB receptor. It was postulated that this increased death following BDNF withdrawal may be due to glutamate toxicity,as the N-methyl-d-aspartate (NMDA) receptor subunit NR2B was up-regulated in the cultures. Indeed,blocking glutamate signaling,not just through the NMDA but also mGlu and AMPA/Kainate receptors,completely reversed the cell death phenotype. This study suggests that the pathogenesis of JHD may involve in part a population of 'persistent' neural progenitors that are selectively vulnerable to BDNF withdrawal. Similar results were seen in adult hippocampal-derived neural progenitors isolated from the BACHD model mouse. Together,these results provide important insight into HD mechanisms at early developmental time points,which may suggest novel approaches to HD therapeutics. View Publication

Neurodegenerative diseases are characterized by chronic and progressive structural or functional loss of neurons. Limitations related to the animal models of these human diseases have impeded the development of effective drugs. This emphasizes the need to establish disease models using human-derived cells. The discovery of induced pluripotent stem cell (iPSC) technology has provided novel opportunities in disease modeling,drug development,screening,and the potential for patient-matched" cellular therapies in neurodegenerative diseases. In this study� View Publication

Culturing human embryonic stem and induced pluripotent stem cells (hESCs/iPSCs) is one of the most costly and labor-intensive tissue cultures,as media containing expensive factors/cytokines should be changed every day to maintain and propagate undifferentiated hESCs/iPSCs in vitro. We recently reported that doxycycline,an anti-bacterial agent,had dramatic effects on hESC/iPSC survival and promoted self-renewal. In this study,we extended the effects of doxycycline to a more practical issue to save cost and labor in hESC/iPSC cultures. Regardless of cultured cell conditions,hESCs/iPSCs in doxycycline-supplemented media were viable and proliferating for at least 3 days without media change,while none or few viable cells were detected in the absence of doxycycline in the same conditions. Thus,hESCs/iPSCs supplemented with doxycycline can be cultured for a long period of time with media changes at 3-day intervals without altering their self-renewal and pluripotent properties,indicating that doxycycline supplementation can reduce the frequency of media changes and the amount of media required by 1/3. These findings strongly encourage the use of doxycycline to save cost and labor in culturing hESCs/iPSCs. View Publication

Induced pluripotent stem cells (iPSCs) were generated from peripheral blood mononuclear cells (PBMCs) isolated from the whole blood of a 43-year-old male with hypertrophic cardiomyopathy (HCM) who carries the pathogenic variant p.Val698Ala in beta-myosin heavy chain (MYH7). Patient-derived PBMCs were reprogrammed using non-integrative episomal vectors containing reprogramming factors OCT4,SOX2,LIN28,KLF4 and L-MYC. iPSCs were shown to express pluripotent markers,have trilineage differentiation potential,carry the pathogenic MYH7 variant p.Val698Ala,have a normal karyotype and no longer carry the episomal reprogramming vector. This line is useful for studying the link between variants in MYH7 and the pathogenesis of HCM. View Publication

BACKGROUND Thrombocytopenia leading to life-threatening excessive bleeding can be treated by platelet transfusion. Currently,such treatments are totally dependent on donor-derived platelets. To support future applications in the use of in vitro-derived platelets,we sought to identify genes whose manipulation might improve the efficiency of megakaryocyte production and resulting hemostatic effectiveness. Disruption of Lyn kinase has previously been shown to improve cell survival,megakaryocyte ploidy and TPO-mediated activation in mice,but its role in human megakaryocytes and platelets has not been examined. METHODS To analyze the role of Lyn at defined differentiation stages during human megakaryocyte differentiation,conditional Lyn-deficient cells were generated using CRISPR/Cas9 technology in iPS cells. The efficiency of Lyn-deficient megakaryocytes to differentiate and become activated in response to a range of platelet agonists was analyzed in iPSC-derived megakaryocytes. RESULTS Temporally controlled deletion of Lyn improved the in vitro differentiation of hematopoietic progenitor cells into mature megakaryocytes,as measured by the rate and extent of appearance of CD41+ CD42+ cells. Lyn-deficient megakaryocytes also demonstrated improved hemostatic effectiveness,as reported by their ability to mediate clot formation in rotational thromboelastometry. Finally,Lyn-deficient megakaryocytes produced increased numbers of platelet-like particles (PLP) in vitro. CONCLUSIONS Conditional deletion of Lyn kinase increases the hemostatic effectiveness of megakaryocytes and their progeny as well as improving their yield. Adoption of this system during generation of in vitro-derived platelets may contribute to both their efficiency of production and their ability to support hemostasis. View Publication

The immune-modulatory effects of mesenchymal stromal cells (MSCs) are widely used to treat inflammatory disorders,with indoleamine 2,4-dioxygenase-1 (IDO-1) playing a pivotal role in suppressing stimulated T-cell proliferation. Taking that three-dimensional (3D) cultures enhance MSCs’ anti-inflammatory properties compared with two-dimensional (2D) cultures,the differentially expressed miRNAs were examined. Thus,we identified hsa-miR-4662a-5p (miR-4662a) as a key inducer of IDO-1 via its suppression of bridging integrator-1 (BIN-1),a negative regulator of the IDO-1 gene. The IDO-1-inducing potential of miR-4662a was conserved across primary MSCs from various donors and sources but exhibited variability. Notably,iPSC-derived MSCs (iMSCs) demonstrated superior IDO-1 induction and immune-modulatory efficacy compared with their donor-matched primary MSCs. Accordingly,iMSCs expressing miR-4662a (4662a/iMSC) exhibited stronger suppressive effects on T-cell proliferation and more potent suppressive effects on graft-versus-host disease (GVHD),improving survival rates and reducing tissue damage in the liver and gut. Our results point to the therapeutic potential of standardized,off-the-shelf 4662a/iMSC as a robust immune-modulating cell therapy for GVHD. View Publication

ObjectiveThyroid hormone (TH) action is mediated by thyroid hormone receptor (THR) isoforms. While THR?1 is likely the main isoform expressed in liver,its role in human hepatocytes is not fully understood.MethodsTo elucidate the role of THR?1 action in human hepatocytes we used CRISPR/Cas9 editing to knock out THR?1 in induced pluripotent stem cells (iPSC). Following directed differentiation to the hepatic lineage,iPSC-derived hepatocytes were then interrogated to determine the role of THR?1 in ligand-independent and -dependent functions.ResultsWe found that the loss of THR?1 promoted alterations in proliferation rate and metabolic pathways regulated by T3,including gluconeogenesis,lipid oxidation,fatty acid synthesis,and fatty acid uptake. We observed that key genes involved in liver metabolism are regulated through both T3 ligand-dependent and -independent THR?1 signaling mechanisms. Finally,we demonstrate that following THR?1 knockout,several key metabolic genes remain T3 responsive suggesting they are THR? targets.ConclusionsThese results highlight that iPSC-derived hepatocytes are an effective platform to study mechanisms regulating TH signaling in human hepatocytes. Graphical abstractImage 1 Highlights•THR?1 is essential for T3 effects in human iPSC-derived hepatocytes (iHEPs).•THR?1 knockout reduces iPSC and progenitor cell proliferative capacity.•T3 regulates key genes involved in lipid and carbohydrate metabolism through THR?1.•THR?1 plays a strong ligand-independent role. View Publication