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

Pericytes (PCs) are endothelium-associated cells that play an important role in normal vascular function and maintenance. We developed a method comparable to GMP quality protocols for deriving self-renewing perivascular progenitors from the human embryonic stem cell (hESC),line ESI-017. We identified a highly scalable,perivascular progenitor cell line that we termed PC-A,which expressed surface markers common to mesenchymal stromal cells. PC-A cells were not osteogenic or adipogenic under standard differentiation conditions and showed minimal angiogenic support function in vitro. PC-A cells were capable of further differentiation to perivascular progenitors with limited differentiation capacity,having osteogenic potential (PC-O) or angiogenic support function (PC-M),while lacking adipogenic potential. Importantly,PC-M cells expressed surface markers associated with pericytes. Moreover,PC-M cells had pericyte-like functionality being capable of co-localizing with human umbilical vein endothelial cells (HUVECs) and enhancing tube stability up to 6 days in vitro. We have thus identified a self-renewing perivascular progenitor cell line that lacks osteogenic,adipogenic and angiogenic potential but is capable of differentiation toward progenitor cell lines with either osteogenic potential or pericyte-like angiogenic function. The hESC-derived perivascular progenitors described here have potential applications in vascular research,drug development and cell therapy. View Publication

Organotin compounds,such as tributyltin (TBT),are well-known endocrine disruptors. TBT is also known to cause various forms of cytotoxicity,including neurotoxicity and immunotoxicity. However,TBT toxicity has not been identified in normal stem cells. In the present study,we examined the effects of TBT on cell growth in human induced pluripotent stem cells (iPSCs). We found that exposure to nanomolar concentrations of TBT decreased intracellular ATP levels and inhibited cell viability in iPSCs. Because TBT suppressed energy production,which is a critical function of the mitochondria,we further assessed the effects of TBT on mitochondrial dynamics. Staining with MitoTracker revealed that nanomolar concentrations of TBT induced mitochondrial fragmentation. TBT also reduced the expression of mitochondrial fusion protein mitofusin 1 (Mfn1),and this effect was abolished by knockdown of the E3 ubiquitin ligase membrane-associated RING-CH 5 (MARCH5),suggesting that nanomolar concentrations of TBT could induce mitochondrial dysfunction via MARCH5-mediated Mfn1 degradation in iPSCs. Thus,mitochondrial function in normal stem cells could be used to assess cytotoxicity associated with metal exposure. View Publication

The ability to generate spiral ganglion neurons (SGNs) from stem cells is a necessary prerequisite for development of cell-replacement therapies for sensorineural hearing loss. We present a protocol that directs human embryonic stem cells (hESCs) toward a purified population of otic neuronal progenitors (ONPs) and SGN-like cells. Between 82% and 95% of these cells express SGN molecular markers,they preferentially extend neurites to the cochlear nucleus rather than nonauditory nuclei,and they generate action potentials. The protocol follows an in vitro stepwise recapitulation of developmental events inherent to normal differentiation of hESCs into SGNs,resulting in efficient sequential generation of nonneuronal ectoderm,preplacodal ectoderm,early prosensory ONPs,late ONPs,and cells with cellular and molecular characteristics of human SGNs. We thus describe the sequential signaling pathways that generate the early and later lineage species in the human SGN lineage,thereby better describing key developmental processes. The results indicate that our protocol generates cells that closely replicate the phenotypic characteristics of human SGNs,advancing the process of guiding hESCs to states serving inner-ear cell-replacement therapies and possible next-generation hybrid auditory prostheses. textcopyright Stem Cells Translational Medicine 2017;6:923-936. View Publication

Glioblastoma Multiforme (GBM) continues to have a poor patient prognosis despite optimal standard of care. Glioma stem cells (GSCs) have been implicated as the presumed cause of tumor recurrence and resistance to therapy. With this in mind,we screened a diverse chemical library of 2,000 compounds to identify therapeutic agents that inhibit GSC proliferation and therefore have the potential to extend patient survival. High-throughput screens (HTS) identified 78 compounds that repeatedly inhibited cellular proliferation,of which 47 are clinically approved for other indications and 31 are experimental drugs. Several compounds (such as digitoxin,deguelin,patulin and phenethyl caffeate) exhibited high cytotoxicity,with half maximal inhibitory concentrations (IC50) in the low nanomolar range. In particular,the FDA approved drug for the treatment of alcoholism,disulfiram (DSF),was significantly potent across multiple patient samples (IC50 of 31.1 nM). The activity of DSF was potentiated by copper (Cu),which markedly increased GSC death. DSF-Cu inhibited the chymotrypsin-like proteasomal activity in cultured GSCs,consistent with inactivation of the ubiquitin-proteasome pathway and the subsequent induction of tumor cell death. Given that DSF is a relatively non-toxic drug that can penetrate the blood-brain barrier,we suggest that DSF should be tested (as either a monotherapy or as an adjuvant) in pre-clinical models of human GBM. Data also support targeting of the ubiquitin-proteasome pathway as a therapeutic approach in the treatment of GBM. View Publication

Plp1 gene expression occurs very early in development,well before the onset of myelination,creating a conundrum with regard to the function of myelin proteolipid protein (PLP),one of the major proteins in compact myelin. Using PLP-EGFP mice to investigate Plp1 promoter activity,we found that,at very early time points,PLP-EGFP was expressed in Sox2+ undifferentiated precursors in the spinal cord ventricular zone (VZ),as well as in the progenitors of both neuronal and glial lineages. As development progressed,most PLP-EGFP-expressing cells gave rise to oligodendrocyte progenitor cells (OPCs). The expression of PLP-EGFP in the spinal cord was quite dynamic during development. PLP-EGFP was highly expressed as cells delaminated from the VZ. Expression was downregulated as cells moved laterally through the cord,and then robustly upregulated as OPCs differentiated into mature myelinating oligodendrocytes. The presence of PLP-EGFP expression in OPCs raises the question of its role in this migratory population. We crossed PLP-EGFP reporter mice into a Plp1-null background to investigate the role of PLP in early OPC development. In the absence of PLP,normal numbers of OPCs were generated and their distribution throughout the spinal cord was unaffected. However,the orientation and length of OPC processes during migration was abnormal in Plp1-null mice,suggesting that PLP plays a role either in the structural integrity of OPC processes or in their response to extracellular cues that orient process outgrowth. View Publication

Human embryonic stem cells (hESCs) and their differentiated progeny allow for investigation of important changes/events during normal embryonic development. Currently most of the research is focused on proteinacous changes occurring as a result of differentiation of stem cells and little is known about changes in cell surface glycosylation patterns. Identification of cell lineage specific glycans can help in understanding their role in maintenance,proliferation and differentiation. Furthermore,these glycans can serve as markers for isolation of homogenous populations of cells. Using a panel of eight biotinylated lectins,the glycan expression of hESCs,hESCs-derived human neural progenitors (hNP) cells,and hESCs-derived mesenchymal progenitor (hMP) cells was investigated. Our goal was to identify glycans that are unique for hNP cells and use the corresponding lectins for cell isolation. Flow cytometry and immunocytochemistry were used to determine expression and localization of glycans,respectively,in each cell type. These results show that the glycan expression changes upon differentiation of hESCs and is different for neural and mesenchymal lineage. For example,binding of PHA-L lectin is low in hESCs (14±4.4%) but significantly higher in differentiated hNP cells (99±0.4%) and hMP cells (90±3%). Three lectins: VVA,DBA and LTL have low binding in hESCs and hMP cells,but significantly higher binding in hNP cells. Finally,VVA lectin binding was used to isolate hNP cells from a mixed population of hESCs,hNP cells and hMP cells. This is the first report that compares glycan expression across these human stem cell lineages and identifies significant differences. Also,this is the first study that uses VVA lectin for isolation for human neural progenitor cells. View Publication

Long-term in vitro culture of undifferentiated human embryonic stem cells (hESCs) traditionally requires a fibroblast feeder cell layer. Using feeder cells in hESC cultures is highly laborious and limits large-scale hESC production for potential application in regenerative medicine. Replacing feeder cells with defined human extracellular matrix (ECM) components or synthetic biomaterials would be ideal for large-scale production of clinical-grade hESCs. We tested and compared different feeder cell-free hESC culture methods based on different human ECM proteins,human and animal sera matrices,and a Matrigel matrix. Also selected biomaterials were tested for feeder cell-free propagation of undifferentiated hESCs. The matrices were tested together with conventional and modified hESC culture media,human foreskin fibroblast-conditioned culture medium,chemically defined medium,TeSR1,and modified TeSR1 media. The results showed the undefined,xenogeneic Matrigel to be a superior matrix for hESC culture compared with the purified human ECM proteins,serum matrices,and the biomaterials tested. A long-term,feeder cell-free culture system was successful on Matrigel in combination with mTeSR1 culture medium,but a xeno-free,fully defined,and reproducible feeder cell-free hESC culture method still remains to be developed. View Publication

The subunit genes encoding human chorionic gonadotropin,CGA,and CGB,are up-regulated in human trophoblast. However,they are effectively silenced in choriocarcinoma cells by ectopically expressed POU domain class 5 transcription factor 1 (POU5F1). Here we show that POU5F1 represses activity of the CGA promoter through its interactions with ETS2,a transcription factor required for both placental development and human chorionic gonadotropin subunit gene expression,by forming a complex that precludes ETS2 from interacting with the CGA promoter. Mutation of a POU5F1 binding site proximal to the ETS2 binding site does not alter the ability of POU5F1 to act as a repressor but causes a drop in basal promoter activity due to overlap with the binding site for DLX3. DLX3 has only a modest ability to raise basal CGA promoter activity,but its coexpression with ETS2 can up-regulate it 100-fold or more. The two factors form a complex,and both must bind to the promoter for the combination to be transcriptionally effective,a synergy compromised by POU5F1. Similarly,in human embryonic stem cells,which express ETS2 but not CGA,ETS2 does not occupy its binding site on the CGA promoter but is found instead as a soluble complex with POU5F1. When human embryonic stem cells differentiate in response to bone morphogenetic protein-4 and concentrations of POU5F1 fall and hCG and DLX3 rise,ETS2 then occupies its binding site on the CGA promoter. Hence,a squelching mechanism underpins the transcriptional silencing of CGA by POU5F1 and could have general relevance to how pluripotency is maintained and how the trophoblast lineage emerges from pluripotent precursor cells. View Publication

We have observed karyotypic changes involving the gain of chromosome 17q in three independent human embryonic stem (hES) cell lines on five independent occasions. A gain of chromosome 12 was seen occasionally. This implies that increased dosage of chromosome 17q and 12 gene(s) provides a selective advantage for the propagation of undifferentiated hES cells. These observations are instructive for the future application of hES cells in transplantation therapies in which the use of aneuploid cells could be detrimental. View Publication