搜索结果: 'methocult media formulations for human hematopoietic cells serum containing'

Induced pluripotent stem (iPS) cells hold the potential to revolutionize regenerative medicine through their capacity to generate cells of diverse lineages for future patient-specific cell-based therapies. To facilitate the transition of iPS cells to clinical practice,a variety of technologies have been developed for transgene-free pluripotency reprogramming. We recently reported efficient iPS cell generation from human fibroblasts using synthetic modified mRNAs. Here we describe a stepwise protocol for the generation of modified mRNA-derived iPS 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. The protocol described herein is for reprogramming of human fibroblasts to pluripotency; however,the properties of modified mRNA make it a powerful platform for protein expression,which has broad applicability in directed differentiation,cell fate specification and therapeutic applications. View Publication

Normal prion protein (PrP(c)),an essential substrate for development of prion disease,is widely distributed in hematopoietic cells. Recent evidence that variant Creutzfeldt-Jakob disease can be transmitted by transfusion of red cell preparations has highlighted the need for a greater understanding of the biology of PrP(c) in blood and blood-forming tissues. Here,we show that in contrast to another glycosylphosphoinositol-anchored protein CD59,PrP(c) at the cell surface of cultured human erythroblasts is rapidly internalized through the endosomal pathway,where it colocalizes with the tetraspanin CD63. In the plasma membrane,PrP(c) colocalizes with the tetraspanin CD81. Cross-linking with anti-PrP(c) or anti-CD81 causes clustering of PrP(c) and CD81,suggesting they can share the same microdomain. These data are consistent with a role for tetraspanin-enriched microdomains in trafficking of PrP(c). These results,when taken together with recent evidence that exosomes released from cells as a result of endosomal-mediated recycling to the plasma membrane contain prion infectivity,provide a pathway for the propagation of prion diseases. View Publication

Tissue morphogenesis and organ formation are the consequences of biochemical and biophysical cues that lead to cellular spatial patterning in development. To model such events in vitro,we use PEG-patterned substrates to geometrically confine human pluripotent stem cell colonies and spatially present mechanical stress. Modulation of the WNT/β-catenin pathway promotes spatial patterning via geometric confinement of the cell condensation process during epithelial-mesenchymal transition,forcing cells at the perimeter to express an OCT4+ annulus,which is coincident with a region of higher cell density and E-cadherin expression. The biochemical and biophysical cues synergistically induce self-organizing lineage specification and creation of a beating human cardiac microchamber confined by the pattern geometry. These highly defined human cardiac microchambers can be used to study aspects of embryonic spatial patterning,early cardiac development and drug-induced developmental toxicity. View Publication

Sox6 belongs to the Sry (sex-determining region Y)-related high-mobility-group-box family of transcription factors,which control cell-fate specification of many cell types. Here,we explored the role of Sox6 in human erythropoiesis by its overexpression both in the erythroleukemic K562 cell line and in primary erythroid cultures from human cord blood CD34+ cells. Sox6 induced significant erythroid differentiation in both models. K562 cells underwent hemoglobinization and,despite their leukemic origin,died within 9 days after transduction; primary erythroid cultures accelerated their kinetics of erythroid maturation and increased the number of cells that reached the final enucleation step. Searching for direct Sox6 targets,we found SOCS3 (suppressor of cytokine signaling-3),a known mediator of cytokine response. Sox6 was bound in vitro and in vivo to an evolutionarily conserved regulatory SOCS3 element,which induced transcriptional activation. SOCS3 overexpression in K562 cells and in primary erythroid cells recapitulated the growth inhibition induced by Sox6,which demonstrates that SOCS3 is a relevant Sox6 effector. View Publication

Efficient strategies for precise genome editing in human-induced pluripotent cells (hiPSCs) will enable sophisticated genome engineering for research and clinical purposes. The development of programmable sequence-specific nucleases such as Transcription Activator-Like Effectors Nucleases (TALENs) and Cas9-gRNA allows genetic modifications to be made more efficiently at targeted sites of interest. However,many opportunities remain to optimize these tools and to enlarge their spheres of application. We present several improvements: First,we developed functional re-coded TALEs (reTALEs),which not only enable simple one-pot TALE synthesis but also allow TALE-based applications to be performed using lentiviral vectors. We then compared genome-editing efficiencies in hiPSCs mediated by 15 pairs of reTALENs and Cas9-gRNA targeting CCR5 and optimized ssODN design in conjunction with both methods for introducing specific mutations. We found Cas9-gRNA achieved 7-8× higher non-homologous end joining efficiencies (3%) than reTALENs (0.4%) and moderately superior homology-directed repair efficiencies (1.0 versus 0.6%) when combined with ssODN donors in hiPSCs. Using the optimal design,we demonstrated a streamlined process to generated seamlessly genome corrected hiPSCs within 3 weeks. View Publication

INTRODUCTION: The physiological signals that direct the division and differentiation of the zygote to form a blastocyst,and subsequent embryonic stem cell division and differentiation during early embryogenesis,are unknown. Although a number of growth factors,including the pregnancy-associated hormone human chorionic gonadotropin (hCG) are secreted by trophoblasts that lie adjacent to the embryoblast in the blastocyst,it is not known whether these growth factors directly signal human embryonic stem cells (hESCs).backslashnbackslashnMETHODS: Here we used hESCs as a model of inner cell mass differentiation to examine the hormonal requirements for the formation of embryoid bodies (EB's; akin to blastulation) and neuroectodermal rosettes (akin to neurulation).backslashnbackslashnRESULTS: We found that hCG promotes the division of hESCs and their differentiation into EB's and neuroectodermal rosettes. Inhibition of luteinizing hormone/chorionic gonadotropin receptor (LHCGR) signaling suppresses hESC proliferation,an effect that is reversed by treatment with hCG. hCG treatment rapidly upregulates steroidogenic acute regulatory protein (StAR)-mediated cholesterol transport and the synthesis of progesterone (P4). hESCs express P4 receptor A,and treatment of hESC colonies with P4 induces neurulation,as demonstrated by the expression of nestin and the formation of columnar neuroectodermal cells that organize into neural tubelike rosettes. Suppression of P4 signaling by withdrawing P4 or treating with the P4-receptor antagonist RU-486 inhibits the differentiation of hESC colonies into EB's and rosettes.backslashnbackslashnCONCLUSIONS: Our findings indicate that hCG signaling via LHCGR on hESC promotes proliferation and differentiation during blastulation and neurulation. These findings suggest that trophoblastic hCG secretion and signaling to the adjacent embryoblast could be the commencement of trophic support by placental tissues in the growth and development of the human embryo. View Publication

We have used in vitro and mouse xenograft models to examine the interaction between breast cancer stem cells (CSC) and bone marrow-derived mesenchymal stem cells (MSC). We show that both of these cell populations are organized in a cellular hierarchy in which primitive aldehyde dehydrogenase expressing mesenchymal cells regulate breast CSCs through cytokine loops involving IL6 and CXCL7. In NOD/SCID mice,labeled MSCs introduced into the tibia traffic to sites of growing breast tumor xenografts where they accelerated tumor growth by increasing the breast CSC population. With immunochemistry,we identified MSC-CSC niches in these tumor xenografts as well as in frozen sections from primary human breast cancers. Bone marrow-derived MSCs may accelerate human breast tumor growth by generating cytokine networks that regulate the CSC population. View Publication

The human induced pluripotent stem cell (hiPSC) provides a breakthrough approach that helps overcoming ethical and allergenic challenges posed in application of neural stem cells (NSCs) in targeted cancer gene therapy. However,the tumor-tropic capacity of hiPSC-derived NSCs (hiPS-NSCs) still has much room to improve. Here we attempted to promote the tumor tropism of hiPS-NSCs by manipulating the activity of endogenous miR-199a/214 cluster that is involved in regulation of hypoxia-stimulated cell migration. We first developed a baculovirus-delivered CRISPR interference (CRISPRi) system that sterically blocked the E-box element in the promoter of the miR-199a/214 cluster with an RNA-guided catalytically dead Cas9 (dCas9). We then applied this CRISPRi system to hiPS-NSCs and successfully suppressed the expression of miR-199a-5p,miR-199a-3p,and miR-214 in the microRNA gene cluster. Meanwhile,the expression levels of their targets related to regulation of hypoxia-stimulated cell migration,such as HIF1A,MET,and MAPK1,were upregulated. Further migration assays demonstrated that the targeted inhibition of the miR-199a/214 cluster significantly enhanced the tumor tropism of hiPS-NSCs both in vitro and in vivo. These findings suggest a novel application of CRISPRi in NSC-based tumor-targeted gene therapy. View Publication

The study of the regulatory signaling hierarchies of human heart development is limited by a lack of model systems that can reproduce the precise developmental events that occur during human embryogenesis. The advent of human pluripotent stem cell (hPSC) technology and robust cardiac differentiation methods affords a unique opportunity to monitor the full course of cardiac induction in vitro. Here,we show that stage-specific activation of insulin signaling strongly inhibited cardiac differentiation during a monolayer-based differentiation protocol that used transforming growth factor β superfamily ligands to generate cardiomyocytes. However,insulin did not repress cardiomyocyte differentiation in a defined protocol that used small molecule regulators of canonical Wnt signaling. By examining the context of insulin inhibition of cardiomyocyte differentiation,we determined that the inhibitory effects by insulin required Wnt/β-catenin signaling and that the cardiomyocyte differentiation defect resulting from insulin exposure was rescued by inhibition of Wnt/β-catenin during the cardiac mesoderm (Nkx2.5+) stage. Thus,insulin and Wnt/β-catenin signaling pathways,as a network,coordinate to influence hPSC differentiation to cardiomyocytes,with the Wnt/β-catenin pathway dominant to the insulin pathway. Our study contributes to the understanding of the regulatory hierarchies of human cardiomyocyte differentiation and has implications for modeling human heart development. View Publication

BACKGROUND Protection of cerebral endothelial cells (ECs) from hypoxia/reoxygenation (H/R)-induced injury is an important strategy for treating ischemic stroke. In this study,we investigated whether co-culture with endothelial progenitor cells (EPCs) and neural progenitor cells (NPCs) synergistically protects cerebral ECs against H/R injury and the underlying mechanism. RESULTS EPCs and NPCs were respectively generated from inducible pluripotent stem cells. Human brain ECs were used to produce an in vitro H/R-injury model. Data showed: 1) Co-culture with EPCs and NPCs synergistically inhibited H/R-induced reactive oxygen species (ROS) over-production,apoptosis,and improved the angiogenic and barrier functions (tube formation and permeability) in H/R-injured ECs. 2) Co-culture with NPCs up-regulated the expression of vascular endothelial growth factor receptor 2 (VEGFR2). 3) Co-culture with EPCs and NPCs complementarily increased vascular endothelial growth factor (VEGF) and brain-derived neurotrophic factor (BDNF) levels in conditioned medium,and synergistically up-regulated the expression of p-Akt/Akt and p-Flk1/VEGFR2 in H/R-injured ECs. 4) Those effects could be decreased or abolished by inhibition of both VEGFR2 and tyrosine kinase B (TrkB) or phosphatidylinositol-3-kinase (PI3K). CONCLUSIONS Our data demonstrate that EPCs and NPCs synergistically protect cerebral ECs from H/R-injury,via activating the PI3K/Akt pathway which mainly depends on VEGF and BDNF paracrine. View Publication