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BACKGROUND: Endothelial cells line the luminal surface of blood vessels and form a barrier between the blood and other tissues of the body. Ets variant 2 (ETV2) is transiently expressed in both zebrafish and mice and is necessary and sufficient for vascular endothelial cell specification. Overexpression of this gene in early zebrafish and mouse embryos results in ectopic appearance of endothelial cells. Ectopic expression of ETV2 in later development results in only a subset of cells responding to the signal.backslashnbackslashnFINDINGS: We have examined the expression pattern of ETV2 in differentiating human embryonic stem cells (ESCs) to determine when the peak of ETV2 expression occurs. We show that overexpression of ETV2 in differentiating human ESC is able to increase the number of endothelial cells generated when administered during or after the endogenous peak of gene expression.backslashnbackslashnCONCLUSIONS: Addition of exogenous ETV2 to human ESCs significantly increased the number of cells expressing angioblast genes without arterial or venous specification. This may be a viable solution to generate in vitro endothelial cells for use in research and in the clinic. View Publication

For diseases of the brain,the pig (Sus scrofa) is increasingly being used as a model organism that shares many anatomical and biological similarities with humans. We report that pig induced pluripotent stem cells (iPSC) can recapitulate events in early mammalian neural development. Pig iPSC line (POU5F1(high)/SSEA4(low)) had a higher potential to form neural rosettes (NR) containing neuroepithelial cells than either POU5F1(low)/SSEA4(low) or POU5F1(low)/SSEA4(high) lines. Thus,POU5F1 and SSEA4 pluripotency marker profiles in starting porcine iPSC populations can predict their propensity to form more robust NR populations in culture. The NR were isolated and expanded in vitro,retaining their NR morphology and neuroepithelial molecular properties. These cells expressed anterior central nervous system fate markers OTX2 and GBX2 through at least seven passages,and responded to retinoic acid,promoting a more posterior fate (HOXB4+,OTX2-,and GBX2-). These findings offer insight into pig iPSC development,which parallels the human iPSC in both anterior and posterior neural cell fates. These in vitro similarities in early neural differentiation processes support the use of pig iPSC and differentiated neural cells as a cell therapy in allogeneic porcine neural injury and degeneration models,providing relevant translational data for eventual human neural cell therapies. View Publication

The neutralization of integrin α4 (Itga4) is currently used as treatment in multiple sclerosis. Although most studies have focused on its function on lymphocyte migration to the CNS,we have uncovered the importance of Itga4 for the generation of regulatory B cells in peripheral immune organs and their control of pathogenic T cell response and CNS pathology. Our study underscores the importance of looking at the dual role of B cells in CNS autoimmunity and provides important perspectives regarding the efficacy and side effects associated with Itga4 neutralization and other B cell-targeting therapies. View Publication

Lineage specific human embryonic stem cell (hESC) reporter cell line is a versatile tool for biological studies on real time monitoring of differentiation,physiological and biochemical features of special cell types and pathological mechanism of disease. Here we report the generation of ChAT-zsGreen reporter hESC line that express zsGreen under the control of the choline acetyltransferase (ChAT) promoter using CRISPR (Clustered Regularly Interspersed Short Palindromic Repeats)/Cas9 system. We show that the ChAT-zsGreen hESC reporter cell lines retain the features of undifferentiated hESC. After cholinergic neuronal differentiation,cholinergic neurons were clearly labeled with green fluorescence protein (zsGreen). The ChAT-zsGreen reporter hESC lines are invaluable not only for the monitoring cholinergic neuronal differentiation but also for study physiological and biochemical hallmarks of cholinergic neurons. View Publication

There are many reports of defined culture systems for the propagation of human embryonic stem cells in the absence of feeder cell support,but no previous study has undertaken a multi-laboratory comparison of these diverse methodologies. In this study,five separate laboratories,each with experience in human embryonic stem cell culture,used a panel of ten embryonic stem cell lines (including WA09 as an index cell line common to all laboratories) to assess eight cell culture methods,with propagation in the presence of Knockout Serum Replacer,FGF-2,and mouse embryonic fibroblast feeder cell layers serving as a positive control. The cultures were assessed for up to ten passages for attachment,death,and differentiated morphology by phase contrast microscopy,for growth by serial cell counts,and for maintenance of stem cell surface marker expression by flow cytometry. Of the eight culture systems,only the control and those based on two commercial media,mTeSR1 and STEMPRO,supported maintenance of most cell lines for ten passages. Cultures grown in the remaining media failed before this point due to lack of attachment,cell death,or overt cell differentiation. Possible explanations for relative success of the commercial formulations in this study,and the lack of success with other formulations from academic groups compared to previously published results,include: the complex combination of growth factors present in the commercial preparations; improved development,manufacture,and quality control in the commercial products; differences in epigenetic adaptation to culture in vitro between different ES cell lines grown in different laboratories. View Publication

Endocannabinoids are arachidonic acid derivatives and part of a novel bioactive lipid signaling system,along with their G-coupled cannabinoid receptors (CB�? and CB₂) and the enzymes involved in their biosynthesis and degradation. However,their roles in hematopoiesis and hematopoietic stem and progenitor cell (HSPC) functions are not well characterized. Here,we show that bone marrow stromal cells express endocannabinoids (anandamide and 2-arachidonylglycerol),whereas CB₂ receptors are expressed in human and murine HSPCs. On ligand stimulation with CB₂ agonists,CB₂ receptors induced chemotaxis,migration,and enhanced colony formation of bone marrow cells,which were mediated via ERK,PI3-kinase,and Gαi-Rac1 pathways. In vivo,the CB₂ agonist AM1241 induced mobilization of murine HSPCs with short- and long-term repopulating abilities. In addition,granulocyte colony-stimulating factor -induced mobilization of HSPCs was significantly decreased by specific CB₂ antagonists and was impaired in Cnr2(-/-) cannabinoid type 2 receptor knockout mice. Taken together,these results demonstrate that the endocannabinoid system is involved in hematopoiesis and that CB₂/CB₂ agonist axis mediates repopulation of hematopoiesis and mobilization of HSPCs. Thus,CB₂ agonists may be therapeutically applied in clinical conditions,such as bone marrow transplantation. View Publication

PURPOSE To investigate the expression status and clinical implications of stem cell genes CD133 and CD44 in the colorectal cancers with early liver metastasis. MATERIALS AND METHODS The differential genes of early liver metastases in colorectal cancer were detected by RT(2) Profiler™ PCR Array. The expression and the relationship of stem cell gene CD133 and CD44 were analyzed by immunofluorescent tests. RESULTS CD133 and CD44 were significantly higher co-expressed in colorectal cancer with early liver metastases compared to those without early liver metastases,and the content of CD133 and CD44 proteins decreased following growth of the transplanted tumors. Of the 80 cases without early liver metastases,12 were observed CD133 and CD44 proteins co-expression,while 36 of the 40 cases with early liver metastases were found CD133 and CD44 proteins co-expression (15% vs. 90%,P textless 0.05). Survival analysis revealed CD133 and CD44 proteins co-expression was associated with poorest prognosis (57.14% vs. 87.41%,X(2) = 48.49,P = 0.001). After Cox regression,age,Duck's stage,lymph node metastasis,and CD133 and CD44 proteins co-expression were shown to be the independent prognostic factors of colorectal cancers. CONCLUSIONS CD133 and CD44 proteins were highly co-expressed in colorectal cancer with early liver metastases,and may be a potential biomarker for the early liver metastases. View Publication

Measuring spatial and temporal patterns of cytochemical variation in human embryonic stem cell (hESC) colonies is necessary for understanding the role of cellular communication in spontaneous differentiation,the mechanisms of biological niche creation,and structure-generating developmental processes. Such insights will ultimately facilitate directed differentiation and therewith promote advances in tissue engineering and regenerative medicine. However,the patterns of cytochemical inhomogeneities of hESC colonies are not well studied and their causes are not fully understood. We used Raman spectroscopic mapping to contrast supracellular variations in cytochemical composition across pluripotent and partly differentiated hESC colonies to gain a better understanding of the early-stage (i.e.,5 days) effects of the differentiation process on the nature and evolution of these patterns. Higher protein-to-nucleic acid ratios,a differentiation status indicator observed previously using Raman spectroscopy,confirmed reported results that spontaneous differentiation is more pronounced on the edges of a colony than elsewhere. In addition,pluripotent and partly differentiated colonies also showed higher lipid concentrations relative to nucleic acids at colony edges in contrast to relative glycogen concentrations,which were up to 400% more pronounced in the colony centers compared to their edges. Pluripotent and partly differentiated colonies differed,with the latter having higher average protein-to-nucleic acid and lipid-to-nucleic acid ratios but a lower glycogen-to-nucleic acid ratio. In both cases,cell density,pluripotency,and high glycogen appeared to vary in tandem. Spatial variations in glycogen- and protein-to-nucleic acid ratios have features on the order of 100 μm and larger. These dimensions are consistent with those reported for stem cell niches and suggest that cytochemical inhomogeneities may provide colony-level information about niches and niche formation. These results demonstrate Raman mapping to be a potentially useful technique for revealing the complexities in the spatial organization of hESC cultures and thus for monitoring the evolution of engineered hESC niches. View Publication

Adult stem-cell therapy holds promise for the treatment of gastrointestinal diseases. Here we describe methods for long-term expansion of colonic stem cells positive for leucine-rich repeat containing G protein-coupled receptor 5 (Lgr5(+) cells) in culture. To test the transplantability of these cells,we reintroduced cultured GFP(+) colon organoids into superficially damaged mouse colon. The transplanted donor cells readily integrated into the mouse colon,covering the area that lacked epithelium as a result of the introduced damage in recipient mice. At 4 weeks after transplantation,the donor-derived cells constituted a single-layered epithelium,which formed self-renewing crypts that were functionally and histologically normal. Moreover,we observed long-term (textgreater6 months) engraftment with transplantation of organoids derived from a single Lgr5(+) colon stem cell after extensive in vitro expansion. These data show the feasibility of colon stem-cell therapy based on the in vitro expansion of a single adult colonic stem cell. View Publication

Herpesvirus saimiri (HVS) infects a range of human cell types with high efficiency. Upon infection,the viral genome can persist as high-copy-number,circular,nonintegrated episomes that segregate to progeny cells upon division. This allows HVS-based vectors to stably transduce a dividing cell population and provide sustained transgene expression in vitro and in vivo. Moreover,the HVS episome is able to persist and provide prolonged transgene expression during in vitro differentiation of mouse and human hemopoietic progenitor cells. Together,these properties are advantageous for induced pluripotent stem cell (iPSC) technology,whereby stem cell-like cells are generated from adult somatic cells by exogenous expression of specific reprogramming factors. Here we assess the potential of HVS-based vectors for the generation of induced pluripotent cancer stem-like cells (iPCs). We demonstrate that HVS-based exogenous delivery of Oct4,Nanog,and Lin28 can reprogram the Ewing's sarcoma family tumor cell line A673 to produce stem cell-like colonies that can grow under feeder-free stem cell culture conditions. Further analysis of the HVS-derived putative iPCs showed some degree of reprogramming into a stem cell-like state. Specifically,the putative iPCs had a number of embryonic stem cell characteristics,staining positive for alkaline phosphatase and SSEA4,in addition to expressing elevated levels of pluripotent marker genes involved in proliferation and self-renewal. However,differentiation trials suggest that although the HVS-derived putative iPCs are capable of differentiation toward the ectodermal lineage,they do not exhibit pluripotency. Therefore,they are hereby termed induced multipotent cancer cells. View Publication

BACKGOUND The purpose of this study was to assess the biological and clinical effects of n-acetyl-cysteine (NAC) in Parkinson's disease (PD). METHODS The overarching goal of this pilot study was to generate additional data about potentially protective properties of NAC in PD,using an in vitro and in vivo approach. In preparation for the clinical study we performed a cell tissue culture study with human embryonic stem cell (hESC)-derived midbrain dopamine (mDA) neurons that were treated with rotenone as a model for PD. The primary outcome in the cell tissue cultures was the number of cells that survived the insult with the neurotoxin rotenone. In the clinical study,patients continued their standard of care and were randomized to receive either daily NAC or were a waitlist control. Patients were evaluated before and after 3 months of receiving the NAC with DaTscan to measure dopamine transporter (DAT) binding and the Unified Parkinson's Disease Rating Scale (UPDRS) to measure clinical symptoms. RESULTS The cell line study showed that NAC exposure resulted in significantly more mDA neurons surviving after exposure to rotenone compared to no NAC,consistent with the protective effects of NAC previously observed. The clinical study showed significantly increased DAT binding in the caudate and putamen (mean increase ranging from 4.4% to 7.8%; ptextless0.05 for all values) in the PD group treated with NAC,and no measurable changes in the control group. UPDRS scores were also significantly improved in the NAC group (mean improvement of 12.9%,p = 0.01). CONCLUSIONS The results of this preliminary study demonstrate for the first time a potential direct effect of NAC on the dopamine system in PD patients,and this observation may be associated with positive clinical effects. A large-scale clinical trial to test the therapeutic efficacy of NAC in this population and to better elucidate the mechanism of action is warranted. TRIAL REGISTRATION ClinicalTrials.gov NCT02445651. View Publication

Incorporation of thymidine analogues in replicating DNA,coupled with antibody and fluorophore staining,allows analysis of cell proliferation,but is currently limited to monolayer cultures,fixed cells and end-point assays. We describe a simple microscopy imaging method for live real-time analysis of cell proliferation,S phase progression over several division cycles,effects of anti-proliferative drugs and other applications. It is based on the prominent (˜ 1.7-fold) quenching of fluorescence lifetime of a common cell-permeable nuclear stain,Hoechst 33342 upon the incorporation of 5-bromo-2'-deoxyuridine (BrdU) in genomic DNA and detection by fluorescence lifetime imaging microscopy (FLIM). We show that quantitative and accurate FLIM technique allows high-content,multi-parametric dynamic analyses,far superior to the intensity-based imaging. We demonstrate its uses with monolayer cell cultures,complex 3D tissue models of tumor cell spheroids and intestinal organoids,and in physiological study with metformin treatment. View Publication