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

Insulin resistance is central to diabetes and metabolic syndrome. To define the consequences of genetic insulin resistance distinct from those secondary to cellular differentiation or in vivo regulation,we generated induced pluripotent stem cells (iPSCs) from individuals with insulin receptor mutations and age-appropriate control subjects and studied insulin signaling and gene expression compared with the fibroblasts from which they were derived. iPSCs from patients with genetic insulin resistance exhibited altered insulin signaling,paralleling that seen in the original fibroblasts. Insulin-stimulated expression of immediate early genes and proliferation were also potently reduced in insulin resistant iPSCs. Global gene expression analysis revealed marked differences in both insulin-resistant iPSCs and corresponding fibroblasts compared with control iPSCs and fibroblasts. Patterns of gene expression in patients with genetic insulin resistance were particularly distinct in the two cell types,indicating dependence on not only receptor activity but also the cellular context of the mutant insulin receptor. Thus,iPSCs provide a novel approach to define effects of genetically determined insulin resistance. This study demonstrates that effects of insulin resistance on gene expression are modified by cellular context and differentiation state. Moreover,altered insulin receptor signaling and insulin resistance can modify proliferation and function of pluripotent stem cell populations. View Publication

Human embryonic stem cells (hESCs) are capable of extensive self-renewal and expansion and can differentiate into any somatic tissue,making them useful for regenerative medicine applications. Allogeneic transplantation of hESC-derived tissues from results in immunological rejection absent adjunctive immunosuppression. The goal of our study was to generate a universal pluripotent stem cell source by nucleofecting a mutated human leukocyte antigen G (mHLA-G) gene into hESCs using the PiggyBac transposon. We successfully generated stable mHLA-G(EF1$\$)-hESC lines using chEF1$\$ system that stably expressed mHLA-G protein during prolonged undifferentiated proliferation andin differentiated embryoid bodies as well as teratomas. Morphology,karyotype,and telomerase activity of mHLA-G expressing hESC were normal. Immunofluorescence staining and flow cytometry analysis revealed persistent expression of pluripotent markers,OCT-3/4 and SSEA-4,in undifferentiated mHLA-G(EF1$\$)-hESC. Nucleofected hESC formed teratomas and when directed to differentiate into epidermal precursors,expressed high levels of mHLA-G and keratinocyte markers K14 and CD29. Natural killer cell cytotoxicity assays demonstrated a significant decrease in lysis of mHLA-G(EF1a)-hESC targets relative to control cells. Similar results were obtained with mHLA-G(EF1$\$)-hESC-derived epidermal progenitors (hEEP). One way mixed T lymphocyte reactions unveiled that mHLA-G(EF1a)-hESC and -hEEP restrained the proliferative activity of mixed T lymphocytes. We conclude that heterologous expression of mHLA-G decreases immunogenicity of hESCs and their epidermal differentiated derivatives. View Publication

CRISPR/Cas9 has demonstrated a high-efficiency in site-specific gene targeting. However,potential off-target effects of the Cas9 nuclease represent a major safety concern for any therapeutic application. Here,we knock out the Tafazzin gene by CRISPR/Cas9 in human-induced pluripotent stem cells with 54% efficiency. We combine whole-genome sequencing and deep-targeted sequencing to characterise the off-target effects of Cas9 editing. Whole-genome sequencing of Cas9-modified hiPSC clones detects neither gross genomic alterations nor elevated mutation rates. Deep sequencing of in silico predicted off-target sites in a population of Cas9-treated cells further confirms high specificity of Cas9. However,we identify a single high-efficiency off-target site that is generated by a common germline single-nucleotide variant (SNV) in our experiment. Based on in silico analysis,we estimate a likelihood of SNVs creating off-target sites in a human genome to be ˜1.5-8.5%,depending on the genome and site-selection method,but also note that mutations might be generated at these sites only at low rates and may not have functional consequences. Our study demonstrates the feasibility of highly specific clonal ex vivo gene editing using CRISPR/Cas9 and highlights the value of whole-genome sequencing before personalised CRISPR design. View Publication

Despite major advances in the pathophysiological understanding of peripheral nerve damage,the treatment of nerve injuries still remains an unmet medical need. Nerve guidance conduits present a promising treatment option by providing a growth-permissive environment that 1) promotes neuronal cell survival and axon growth and 2) directs axonal extension. To this end,we designed an electrospun nerve guidance conduit using a blend of polyurea and poly-caprolactone with both biochemical and topographical cues. Biochemical cues were integrated into the conduit by functionalizing the polyurea with RGD to improve cell attachment. Topographical cues that resemble natural nerve tissue were incorporated by introducing intraluminal microchannels aligned with nanofibers. We determined that electrospinning the polymer solution across a two electrode system with dissolvable sucrose fibers produced a polymer conduit with the appropriate biomimetic properties. Human neural stem cells were cultured on the conduit to evaluate its ability to promote neuronal growth and axonal extension. The nerve guidance conduit was shown to enhance cell survival,migration,and guide neurite extension. View Publication

Angelman syndrome (AS) and Prader-Willi syndrome (PWS),two distinct neurodevelopmental disorders,result from loss of expression from imprinted genes in the chromosome 15q11-13 locus most commonly caused by a megabase-scale deletion on either the maternal or paternal allele,respectively. Each occurs at an approximate incidence of 1/15,000 to 1/30,000 live births and has a range of debilitating phenotypes. Patient-derived induced pluripotent stem cells (iPSCs) have been valuable tools to understand human-relevant gene regulation at this locus and have contributed to the development of therapeutic approaches for AS. Nonetheless,gaps remain in our understanding of how these deletions contribute to dysregulation and phenotypes of AS and PWS. Variability across cell lines due to donor differences,reprogramming methods,and genetic background make it challenging to fill these gaps in knowledge without substantially increasing the number of cell lines used in the analyses. Isogenic cell lines that differ only by the genetic mutation causing the disease can ease this burden without requiring such a large number of cell lines. Here,we describe the development of isogenic human embryonic stem cell (hESC) lines modeling the most common genetic subtypes of AS and PWS. These lines allow for a facile interrogation of allele-specific gene regulation at the chromosome 15q11-q13 locus. Additionally,these lines are an important resource to identify and test targeted therapeutic approaches for patients with AS and PWS. View Publication

Head and neck squamous cell carcinoma (HNSCC) is a highly malignant disease,and death rates have remained at approximately 50% for decades. New tumor-targeting strategies are desperately needed,and a previous report indicated the triggered differentiation of HPV-negative HNSCC cells to confer therapeutic benefits. Using patient-derived tumor cells,we created a similar HNSCC differentiation model of HPV+ tumor cells from two patients. We observed a loss of malignant characteristics in differentiating cell culture conditions,including irregularly enlarged cell morphology,cell cycle arrest with downregulation of Ki67,and reduced cell viability. RNA-Seq showed myocyte-like differentiation with upregulation of markers of myofibril assembly. Immunofluorescence staining of differentiated and undifferentiated primary HPV+ HNSCC cells confirmed an upregulation of these markers and the formation of parallel actin fibers reminiscent of myoblast-lineage cells. Moreover,immunofluorescence of HPV+ tumor tissue revealed areas of cells co-expressing the identified markers of myofibril assembly,HPV surrogate marker p16,and stress-associated basal keratinocyte marker KRT17,indicating that the observed myocyte-like in vitro differentiation occurs in human tissue. We are the first to report that carcinoma cells can undergo a triggered myocyte-like differentiation,and our study suggests that the targeted differentiation of HPV+ HNSCCs might be therapeutically valuable. Subject terms: Oral cancer,Mechanisms of disease,Cell death View Publication

Human pluripotent stem cells including induced pluripotent stem cells (iPSCs) and embryonic stem cells hold great promise for cell-based therapies,but safety concerns that complicate consideration for routine clinical use remain. Installing a safety switch" based on the inducible caspase-9 (iCASP9) suicide gene system should offer added control over undesirable cell replication or activity. Previous studies utilized lentiviral vectors to integrate the iCASP9 system into T cells and iPSCs. This method results in random genomic insertion of the suicide switch and inefficient killing of the cells after the switch is "turned on" with a small molecule (eg AP1903). To improve the safety and efficiency of the iCASP9 system for use in iPSC-based therapy we precisely installed the system into a genomic safe harbor the AAVS1 locus in the PPP1R12C gene. We then evaluated the efficiencies of different promoters to drive iCASP9 expression in human iPSCs. We report that the commonly used EF1$\alpha$ promoter is silenced in iPSCs and that the endogenous promoter of the PPP1R12C gene is not strong enough to drive high levels of iCASP9 expression. However the CAG promoter induces strong and stable iCASP9 expression in iPSCs and activation of this system with AP1903 leads to rapid killing and complete elimination of iPSCs and their derivatives including MSCs and chondrocytes in vitro. Furthermore iPSC-derived teratomas shrank dramatically or were completely eliminated after administration of AP1903 in mice. Our data suggest significant improvements on existing iCASP9 suicide switch technologies and may serve as a guide to other groups seeking to improve the safety of stem cell-based therapies." View Publication

We examined the potential role of myosin and actin in the release of human immunodeficiency virus type 1 (HIV-1) from infected cells. Wortmannin (100 nM to 5 microM),an effective inhibitor of myosin light chain kinase,blocked the release of HIV-1 from infected T-lymphoblastoid and monocytoid cells in a concentration-dependent manner. Cytochalasin D,a reagent that disrupts the equilibrium between monomeric and polymeric actin,also partially inhibited the release of HIV-1 from the infected cells. At the budding stage,myosin and HIV-1 protein were detected in the same areas on the plasma membrane by using dual-label immunofluorescence microscopy and immunoelectron microscopy. In the presence of 5 microM wortmannin,viral components were observed on the plasma membrane by using immunofluorescence microscopy and electron microscopy,implying that wortmannin did not disturb the transport of viral proteins to the plasma membrane but rather inhibited budding. View Publication

Transplantation of human neural progenitor cells (NPCs) into the brain or spinal cord to replace lost cells,modulate the injury environment,or create a permissive milieu to protect and regenerate host neurons is a promising therapeutic strategy for neurological diseases. Deriving NPCs from human fetal tissue is feasible,although problematic issues include limited sources and ethical concerns. Here we describe a new and abundant source of NPCs derived from human induced pluripotent stem cells (iPSCs). A novel chopping technique was used to transform adherent iPSCs into free-floating spheres that were easy to maintain and were expandable (EZ spheres) (Ebert et al. [2013] Stem Cell Res 10:417–427). These EZ spheres could be differentiated towards NPC spheres with a spinal cord phenotype using a combination of all-trans retinoic acid (RA) and epidermal growth factor (EGF) and fibroblast growth factor-2 (FGF-2) mitogens. Suspension cultures of NPCs derived from human iPSCs or fetal tissue have similar characteristics,although they were not similar when grown as adherent cells. In addition,iPSC-derived NPCs (iNPCs) survived grafting into the spinal cord of athymic nude rats with no signs of overgrowth and with a very similar profile to human fetal-derived NPCs (fNPCs). These results suggest that human iNPCs behave like fNPCs and could thus be a valuable alternative for cellular regenerative therapies of neurological diseases. J. Comp. Neurol. 522:2707–2728,2014. textcopyright 2014 Wiley Periodicals,Inc. View Publication

The transient receptor potential canonical (TRPC) family channels are proposed to be essential for store-operated Ca2+ entry in endothelial cells. Ca2+ signaling is involved in NF-kappaB activation,but the role of store-operated Ca2+ entry is unclear. Here we show that thrombin-induced Ca2+ entry and the resultant AMP-activated protein kinase (AMPK) activation targets the Ca2+-independent protein kinase Cdelta (PKCdelta) to mediate NF-kappaB activation in endothelial cells. We observed that thrombin-induced p65/RelA,AMPK,and PKCdelta activation were markedly reduced by knockdown of the TRPC isoform TRPC1 expressed in human endothelial cells and in endothelial cells obtained from Trpc4 knock-out mice. Inhibition of Ca2+/calmodulin-dependent protein kinase kinase beta downstream of the Ca2+ influx or knockdown of the downstream Ca2+/calmodulin-dependent protein kinase kinase beta target kinase,AMPK,also prevented NF-kappaB activation. Further,we observed that AMPK interacted with PKCdelta and phosphorylated Thr505 in the activation loop of PKCdelta in thrombin-stimulated endothelial cells. Expression of a PKCdelta-T505A mutant suppressed the thrombin-induced but not the TNF-alpha-induced NF-kappaB activation. These findings demonstrate a novel mechanism for TRPC channels to mediate NF-kappaB activation in endothelial cells that involves the convergence of the TRPC-regulated signaling at AMPK and PKCdelta and that may be a target of interference of the inappropriate activation of NF-kappaB associated with thrombosis. View Publication

Protein delivery allows a clinical effect to be directly realized without genetic modification of the host cells. We have developed a cationic bolaamphiphile as a non-viral vector for protein delivery application. The relatively low toxicity and efficient protein delivery by the cationic bolaamphiphile prompted us to test the system for the generation of induced pluripotent stem cells (iPSCs) as an alternative to the conventional vector-based genetic approach. Studies on the kinetics and cytotoxicity of the protein delivery system led us to use an optimized cationic bolaamphiphile-protein complex ratio of 7:1 (wt/wt) and a 3 h period of incubation with human fibroblasts,to ensure complete and non-toxic protein delivery of the reprogramming proteins. The reprogrammed cells were shown to exhibit the characteristics of embryonic stem cells,including expression of pluripotent markers,teratoma formation in SCID mice,and ability to be differentiated into a specific lineage,as exemplified by neuronal differentiation. View Publication

Targeted delivery of siRNA controlled by near-infrared light using hollow gold nanoshells has been demonstrated in cancer and stem cells models. Here,a universal surface module and several functionalization rules for the maximized delivery of short nucleic acids (here,siRNA) applicable for diverse gold nanocarriers are described. Streptavidin is devised as a handle to assemble biotinylated cell penetrating peptides (e.g.,transactivating transcriptional activator (TAT)),as well as an insulator between the positive charge of TAT and the dense negative charge of RNA. However,direct linking of streptavidin to functional siRNA inhibits its silencing activity. The approach then involves the orthogonal assembly of two types of RNA strands: one with biotin modification for cell targeting and penetration (scaffold RNA); the other without biotin as functional RNA (i.e.,siRNA). Initially,flexible single-stranded RNA is used for dense surface-packing,followed by hybridization with the complementary RNA strand to maximize the assembly of the targeting peptide for cellular uptake and siRNA delivery. This orthogonal approach for the delivery of short oligonucleotides,together with novel surface functionalization rules discovered here,should enable the use of these materials for nanomedicinal research and applications. View Publication