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

Enzymatic dissociation of human pluripotent stem cells (hPSCs) into single cells during routine passage leads to massive cell death. Although the Rho-associated protein kinase inhibitor,Y-27632 can enhance hPSC survival and proliferation at high seeding density,dissociated single cells undergo apoptosis at clonal density. This presents a major hurdle when deriving genetically modified hPSC lines since transfection and genome editing efficiencies are not satisfactory. As a result,colonies tend to contain heterogeneous mixtures of both modified and unmodified cells,making it difficult to isolate the desired clone buried within the colony. In this study,we report improved clonal expansion of hPSCs using a retinoic acid analogue,TTNPB. When combined with Y-27632,TTNPB synergistically increased hPSC cloning efficiency by more than 2 orders of magnitude (0.2% to 20%),whereas TTNPB itself increased more than double cell number expansion compared to Y-27632. Furthermore,TTNPB-treated cells showed two times higher aggregate formation and cell proliferation compared to Y-27632 in suspension culture. TTNPB-treated cells displayed a normal karyotype,pluripotency and were able to stochastically differentiate into all three germ layers both in vitro and in vivo. TTNBP acts,in part,by promoting cellular adhesion and self-renewal through the upregulation of Claudin 2 and HoxA1. By promoting clonal expansion,TTNPB provides a new approach for isolating and expanding pure hPSCs for future cell therapy applications. A retinoic acid analogue,TTNPB,improves clonal expansion in adherent and suspension culture of hPSCs by promoting cellular adhesion and self-renewal through the upregulation of Claudin 2 and HoxA1. View Publication

Olive oil intake has been shown to induce significant levels of apoptosis in various cancer cells. These anti-cancer properties are thought to be mediated by phenolic compounds present in olive. These beneficial health effects of olive have been attributed,at least in part,to the presence of oleuropein and hydroxytyrosol. In this study,oleuropein and hydroxytyrosol,major phenolic compound of olive oil,was studied for its effects on growth in MCF-7 human breast cancer cells using assays for proliferation (MTT assay),cell viability (Guava ViaCount assay),cell apoptosis,cellcycle (flow cytometry). Oleuropein or hydroxytyrosol decreased cell viability,inhibited cell proliferation,and induced cell apoptosis in MCF-7 cells. Result of MTT assay showed that 200 mug/mL of oleuropein or 50 mug/mL of hydroxytyrosol remarkably reduced cell viability of MCF-7 cells. Oleuropein or hydroxytyrosol decrease of the number of MCF-7 cells by inhibiting the rate of cell proliferation and inducing cell apoptosis. Also hydroxytyrosol and oleuropein exhibited statistically significant block of G(1) to S phase transition manifested by the increase of cell number in G(0)/G(1) phase. View Publication

Animal models of the neuromuscular junction (NMJ) have been widely studied but exhibit critical differences from human biology limiting utility in drug and disease modelling. Challenges with scarcity,scalability,throughput,and ethical considerations further limit the suitability of animal models for preclinical screening. Engineered models have emerged as alternatives for studying NMJ functionality in response to genetic and/or pharmacological challenge. However,these models have faced challenges associated with their poorly scalable creation,sourcing suitable cells,and the extraction of reliable,quantifiable metrics. We present a turnkey iPSC-based model of the NMJ employing channelrhodopsin-2 expression within the motor neuron (MN) population driving muscle contraction in response to blue light. MNs co-cultured with engineered skeletal muscle tissues produced twitch forces of 34.7 ± 22.7 µN in response to blue light,with a response fidelity > 92 %. Histological analysis revealed characteristic punctate acetylcholine receptor staining co-localized with the presynaptic marker synaptic vesicle protein-2. Dose-response studies using botulinum neurotoxin showed loss of function in a dose- and time-dependent manner (EC50 - 0.11 ± 0.015 µg). Variability of the EC50 values between 2 different iPSC differentiations of both cell types and 2 users was less than 2 %. Further testing with the acute neurotoxins acetylcholine mustard and d-tubocurarine validated the biological relevance of the postsynaptic machinery of the model. This model marks a meaningful progression of 3D engineered models of the NMJ,providing engineered tissues at a throughput relevant to potency and screening applications with an abundant iPSC cell source and standardized hardware-software ecosystem allowing technology transfer across laboratories. View Publication

Because neurons are difficult to obtain from humans,generating functional neurons from human induced pluripotent stem cells (hiPSCs) is important for establishing physiological or disease-relevant screening systems for drug discovery. To examine the culture conditions leading to efficient differentiation of functional neural cells,we investigated the effects of oxygen stress (2% or 20% O2) and differentiation medium (DMEM/F12:Neurobasal-based [DN] or commercial [PhoenixSongs Biologicals; PS]) on the expression of genes related to neural differentiation,glutamate receptor function,and the formation of networks of neurons differentiated from hiPSCs (201B7) via long-term self-renewing neuroepithelial-like stem (lt-NES) cells. Expression of genes related to neural differentiation occurred more quickly in PS and/or 2% O2 than in DN and/or 20% O2,resulting in high responsiveness of neural cells to glutamate,N-methyl-d-aspartate (NMDA),α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA),and (S)-3,5-d... View Publication

Human embryonic stem cells (hESC) are difficult to adapt to 96-well plate assays,such as the MTT assay,because they survive best when plated as colonies,which are not easily counted and plated accurately. Two methods were developed to address this problem. In the first,ROCK inhibitor (ROCKi) was used,which allows accurate counting and plating of single hESC. In the second,small colonies were plated without ROCKi but with adaptations for accurate counting and plating. The MTT assay was also adapted for use with mouse neural stem cells. These methods allow the MTT assay to be conducted rapidly and accurately with high reproducibility between replicate experiments. When screening volatile chemicals in a 96-well plate,vapor effects may occur and dose ranges must be carefully defined. The methods were validated using the NIH assay guidance tool. These methodss could readily be translated to other 96-well plate assay. View Publication

Stem cell therapies hold great promise for repairing tissues damaged due to disease or injury. However,a major obstacle facing this field is the difficulty in identifying cells of a desired phenotype from the heterogeneous population that arises during stem cell differentiation. Conventional fluorescence flow cytometry and magnetic cell purification require exogenous labeling of cell surface markers which can interfere with the performance of the cells of interest. Here,we describe a non-genetic,label-free cell cytometry method based on electrophysiological response to stimulus. As many of the cell types relevant for regenerative medicine are electrically-excitable (e.g. cardiomyocytes,neurons,smooth muscle cells),this technology is well-suited for identifying cells from heterogeneous stem cell progeny without the risk and expense associated with molecular labeling or genetic modification. Our label-free cell cytometer is capable of distinguishing clusters of undifferentiated human induced pluripotent stem cells (iPSC) from iPSC-derived cardiomyocyte (iPSC-CM) clusters. The system utilizes a microfluidic device with integrated electrodes for both electrical stimulation and recording of extracellular field potential (FP) signals from suspended cells in flow. The unique electrode configuration provides excellent rejection of field stimulus artifact while enabling sensitive detection of FPs with a noise floor of 2 $$V(rms). Cells are self-aligned to the recording electrodes via hydrodynamic flow focusing. Based on automated analysis of these extracellular signals,the system distinguishes cardiomyocytes from non-cardiomyocytes. This is an entirely new approach to cell cytometry,in which a cell's functionality is assessed rather than its expression profile or physical characteristics. View Publication

Since the 1960s,the stem cells have been extensively studied including embryonic stem cells,neural stem cells,bone marrow hematopoietic stem cells,and mesenchymal stem cells. In the recent years,several stem cells have been initially used in the treatment of diseases,such as in bone marrow transplant. At the same time,isolation and culture experimental technologies for stem cell research have been widely developed in recent years. In addition,molecular imaging technologies including optical molecular imaging,positron emission tomography,single-photon emission computed tomography,and computed tomography have been developed rapidly in recent the 10 years and have also been used in the research on disease mechanism and evaluation of treatment of disease related with stem cells. This paper will focus on recent typical isolation,culture,and observation techniques of stem cells followed by a concise introduction. Finally,the current challenges and the future applications of the new technologies in stem cells are given according to the understanding of the authors,and the paper is then concluded. View Publication

Mechanisms that maintain cancer stem cells are crucial to tumour progression. The ID2 protein supports cancer hallmarks including the cancer stem cell state. HIFα transcription factors,most notably HIF2α (also known as EPAS1),are expressed in and required for maintenance of cancer stem cells (CSCs). However,the pathways that are engaged by ID2 or drive HIF2α accumulation in CSCs have remained unclear. Here we report that DYRK1A and DYRK1B kinases phosphorylate ID2 on threonine 27 (Thr27). Hypoxia downregulates this phosphorylation via inactivation of DYRK1A and DYRK1B. The activity of these kinases is stimulated in normoxia by the oxygen-sensing prolyl hydroxylase PHD1 (also known as EGLN2). ID2 binds to the VHL ubiquitin ligase complex,displaces VHL-associated Cullin 2,and impairs HIF2α ubiquitylation and degradation. Phosphorylation of Thr27 of ID2 by DYRK1 blocks ID2-VHL interaction and preserves HIF2α ubiquitylation. In glioblastoma,ID2 positively modulates HIF2α activity. Conversely,elevated expression of DYRK1 phosphorylates Thr27 of ID2,leading to HIF2α destabilization,loss of glioma stemness,inhibition of tumour growth,and a more favourable outcome for patients with glioblastoma. View Publication

AIM Bevacizumab has been reported to result in increased tumor invasion when used to treat malignant glioma. We hypothesized that BMP4 would prevent diffuse tumor infiltration induced by bevacizumab for malignant glioma in a xenograft model. METHODS Human glioblastoma (GBM) tumor cells were implanted in the striatum of immunocompromised mice. The animals were treated with bevacizumab and BMP4. Tumor growth and invasion were measured. RESULTS The bevacizumab-treated mice had increased survival compared with control animals (p = 0.02). BMP4 alone did not result in improved survival (p = 1.0). The bevacizumab (p = 0.006) and bevacizumab plus BMP4 (p = 0.006) groups demonstrated significantly decreased total tumor size compared with control. Tumor invasion was significantly decreased in the bevacizumab (p = 0.005),BMP4 (p = 0.04) alone and bevacizumab plus BMP4 (p = 0.002) groups compared with control. No synergistic effect between bevacizumab and BMP4 was observed. CONCLUSION Bevacizumab treatment did not result in diffuse infiltration of human GBM in a mouse xenograft model. BMP4 did have an independent favorable effect on GBM that was not synergistic with bevacizumab treatment. View Publication

We report a system for Cre-regulated expression of RNA interference in vivo. Expression cassettes comprise selectable and FACS-sortable markers in tandem with additional marker genes and shRNAs in the antisense orientation. The cassettes are flanked by tandem LoxP sites arranged so that Cre expression inverts the marker-shRNA construct,allowing its regulated expression (and,at the same time,deletes the original selection/marker genes). The cassettes can be incorporated into retroviral or lentiviral vectors and delivered to cells in culture or used to generate transgenic mice. We describe cassettes incorporating various combinations of reporter genes,miRNA-based RNAi (including two shRNA constructs at once),and oncogenes and demonstrate the delivery of effective RNA interference in cells in culture,efficient transduction into hematopoietic stem cells with cell-type-specific knockdown in their progeny,and rapid generation of regulated shRNA knockdown in transgenic mice. These vector systems allow regulated combinatorial manipulation (both overexpression and loss of function) of gene expression in multiple systems in vitro and in vivo. View Publication