Geron stops human embryonic stem cell tests Geron Corp., the company that started the first U.S.-approved trial of human embryonic stem cells, fell the most in more than 11 years after research costs and regulatory complexities caused it to end the program. The first trial testing Gerons embryonic stem-cell therapy in spinal-cord injury patients began in April. In October, it reported that none of the four patients in the trial had experienced negative reactions to the therapy, consisting of 2 million cells injected into their spines at the damaged site.

Wnt/β-catenin signaling plays a central role in regulating stem cell fates. Its exact role in the maintenance of mouse epiblast stem cells (EpiSCs) and human embryonic stem cells (ESCs), however, remains undefined. Here, we show that activation of Wnt/β-catenin signaling in mouse EpiSCs and human ESCs can promote self-renewal or differentiation, with the self-renewal effect being realized only when β-catenin mediated T-cell factors (TCFs)-dependent transcription activities are blocked. Introduction of a stabilized β-catenin transgene harboring point mutations at the TCF binding site enables mouse EpiSCs and human ESCs to self-renew without exogenous growth factors. By contrast, β-catenin-mediated self-renewal in mouse ESCs requires TCF-binding activity. Moreover, we show that Axin2, but not Axin1, functions to redistribute β-catenin mainly on cell cytoplasm, and accumulated β-catenin in cytoplasm promote both mouse EpiSCs and human ESCs self-renewal and convert mouse ESCs into EpiSCs. Our ...

TY - JOUR. T1 - Differentiation and Transplantation of Human Embryonic Stem Cell-Derived Hepatocytes. AU - Basma, Hesham E. AU - Soto-Gutiérrez, Alejandro. AU - Yannam, Govardhana Rao. AU - Liu, Liping. AU - Ito, Ryotaro. AU - Yamamoto, Toshiyuki. AU - Ellis, Ewa. AU - Carson, Steven D. AU - Sato, Shintaro. AU - Chen, Yong. AU - Muirhead, David. AU - Navarro-Álvarez, Nalu. AU - Wong, Ronald J.. AU - Roy-Chowdhury, Jayanta. AU - Platt, Jeffrey L.. AU - Mercer, David F. AU - Miller, John D.. AU - Strom, Stephen C.. AU - Kobayashi, Naoya. AU - Fox, Ira J.. PY - 2009/3. Y1 - 2009/3. N2 - Background & Aims: The ability to obtain unlimited numbers of human hepatocytes would improve the development of cell-based therapies for liver diseases, facilitate the study of liver biology, and improve the early stages of drug discovery. Embryonic stem cells are pluripotent, potentially can differentiate into any cell type, and therefore could be developed as a source of human hepatocytes. Methods: To generate ...

Cell therapies to repair the failing heart could offer great clinical benefit but few studies directly comparing efficacy between cell types have been performed. Here we sought to compare the cardiac repair efficacy of three promising human cell types: bone marrow mononuclear cells (hBMMNC), human embryonic stem cell-derived cardiomyocytes (hESC-CM) and hESC-derived cardiovascular progenitors (hESC-CVP).. Methods/Results: Myocardial infarction (MI) was performed in athymic nude rats by 60 min ischemia then reperfusion. Baseline echocardiography was performed 4 days after MI before transplantation with 10x10^6 cells into the central infarct region and border zones. Rats were randomly assigned to the following groups: hESC-CVP n=10, hESC-CM n=11, hBMMNC n=11 and non-cardiac cells (control) derived from human ESCs (hNC) n=13. Flow cytometry revealed 77% of hESC-CVP cells were KDR+/PDGFRα+ whilst 69% of hES-CM cells were cardiac troponin-T+. At 4d after MI there was no significant difference in ...

TY - JOUR. T1 - Heterozygous embryonic stem cell lines derived from nonhuman primate parthenotes. AU - Dighe, Vikas. AU - Clepper, Lisa. AU - Pedersen, Darlene. AU - Byrne, James. AU - Ferguson, Betsy. AU - Gokhale, Sumita. AU - Penedo, Cecilia. AU - Wolf, Don. AU - Mitalipov, Shoukhrat. PY - 2008/3/1. Y1 - 2008/3/1. N2 - Monoparental parthenotes represent a potential source of histocompatible stem cells that should be isogenic with the oocyte donor and therefore suitable for use in cell or tissue replacement therapy. We generated five rhesus monkey parthenogenetic embryonic stem cell (PESC) lines with stable, diploid female karyotypes that were morphologically indistinguishable from biparental controls, expressed key pluripotent markers, and generated cell derivatives representative of all three germ layers following in vivo and in vitro differentiation. Interestingly, high levels of heterozygosity were observed at the majority of loci that were polymorphic in the oocyte donors. Some PESC lines ...

Cardiomyocytes derived from human embryonic stem cells (hESCs) are promising candidates to regenerate myocardium as a treatment for heart disease. However, this application is limited because of the inability to prospectively identify a pure population of cardiovascular progenitors (CVPs) that is devoid of residual, undifferentiated cells capable of teratoma formation. Furthermore, the potential of hESC-derived cardiovascular lineage cells to functionally couple to human myocardium remains unknown. The purpose of the current study was to test the hypotheses that (i) CVPs derived from hESCs can be isolated based on a set of distinct surface markers and (ii) they can functionally integrate into the human fetal heart. We screened a large panel of monoclonal antibodies to prospectively identify early cardiovascular precursors that emerge from differentiating hESCs based on the expression of surface markers. We discovered four surface markers that highly enrich for CVPs: receptor tyrosine kinase-like ...

Stem cell Q & A. The scientific community had reason to celebrate when President Barack Obama signed an executive order on March 9 removing the previous administrations restrictions on human embryonic stem cell research. The order lifted the ban on federal funding for research using embryonic stem cell lines created after August 9, 2001, fulfilling one of Obamas campaign promises.. Investigators at the Massachusetts General Hospital Center for Regenerative Medicine are excited by the possibilities presented by the change, hoping it will foster scientific collaboration, new funding and advances in this burgeoning field.. Human embryonic stem cells have the ability to develop into any tissue in the body. Researchers hope to someday use this capability to repair damage to organs and tissue caused by injury and chronic illness.. In the following interview, David Scadden, MD, director of the Center of Regenerative Medicine and codirector of the Harvard Stem Cell Institute, explains what this ...

Human embryonic stem cells (hESCs) can proliferate extensively in culture and give rise to progeny of the three germ layers. Several reports suggested that mouse and hESCs may attenuate immune responses. In this study, we focused on the mechanism by which hESCs inhibit T cell responses. Using coculture experiments, we demonstrate that hESCs inhibit cytokine secretion and T cell proliferation in response to potent T cell activators. Furthermore, we show that hESCs downmodulate the TCR-associated CD3-ζ chain. These effects are maintained when hESCs are replaced by their conditioned media and can be restored by the addition of l-arginine to hESC-conditioned media or by treatment of hESCs with a specific arginase inhibitor. Moreover, we show arginase-I expression and activity in hESCs. We further demonstrate that mouse ESCs (mESCs) similarly inhibit T cell activation via arginase I, suggesting an evolutionary conserved mechanism of T cell suppression by ESCs. In addition, we demonstrate that ...

Pluripotent stem cells are known to display distinct metabolic phenotypes than their somatic counterparts. While accumulating studies are focused on the roles of glucose and amino acid metabolism in facilitating pluripotency, little is known regarding the role of lipid metabolism in regulation of stem cell activities. Here, we show that fatty acid (FA) synthesis activation is critical for stem cell pluripotency. Our initial observations demonstrated enhanced lipogenesis in pluripotent cells and during cellular reprogramming. Further analysis indicated that de novo FA synthesis controls cellular reprogramming and embryonic stem cell pluripotency through mitochondrial fission. Mechanistically, we found that de novo FA synthesis regulated by the lipogenic enzyme ACC1 leads to the enhanced mitochondrial fission via (i) consumption of AcCoA which affects acetylation‐mediated FIS1 ubiquitin-proteasome degradation and (ii) generation of lipid products that drive the mitochondrial dynamic equilibrium ...

Our previous study demonstrated the direct involvement of the HIF-1α subunit in the promotion of cardiac differentiation of murine embryonic stem cells (ESCs). We report the use of cobalt chloride to induce HIF-1α stabilization in human ESCs to promote cardiac differentiation. Treatment of undifferentiated hES2 human ESCs with 50μM cobalt chloride markedly increased protein levels of the HIF-1α subunit, and was associated with increased expression of early cardiac specific transcription factors and cardiotrophic factors including NK2.5, vascular endothelial growth factor, and cardiotrophin-1. When pretreated cells were subjected to cardiac differentiation, a notable increase in the occurrence of beating embryoid bodies and sarcomeric actinin-positive cells was observed, along with increased expression of the cardiac-specific markers, MHC-A, MHC-B, and MLC2V. Electrophysiological study revealed increased atrial-and nodal-like cells in the cobalt chloride-pretreated group. Confocal calcium ...

Human embryonic stem cells (hESCs) have large nucleus-to-cytoplasm ratios and nucleic acid spectral bands are prominent in their characteristic Raman signatures. Under normal conditions, the major variations in these signatures are due to changes in glycogen content, but how these signatures vary in response to different external conditions is largely unknown. In this study we investigated the influences of temperature variations on hESC Raman signatures. At 32 °C, compared to the 37 °C control condition, cell proliferation rates were markedly reduced and glycogen Raman band intensities were elevated. In addition, at both temperatures, an inverse relationship between cell proliferation rates (i.e., onset of exponential growth phase vs. end of exponential phase) and glycogen Raman band intensities was observed. This relationship suggested a role for glycogen in the energy metabolism of hESC self-renewal. Protein and lipid spectral variations were small and co-varied with those of nucleic acids, ...

It is impossible to discuss human embryonic stem cell (HECS) research without also discussing the debate about the ethicality of the research. Many different individual arguments comprise a single, larger debate: Is it ethical to destroy human embryos to alleviate the pain and suffering of existing human lives? The debate polarizes the issue of stem-cell research as a whole, although it applies only to embryonic stem-cell research. Stem-cell research using cells from umbilical cords or adult somatic stem-cells, which are not as useful for research, are not subject to the same controversy. The effects of this debate are readily evident; because of the controversial nature, many religious organizations refuse to acknowledge the benefits of research using embryonic stem-cells, politicians refuse to support research efforts, and federal funding is in a constant state of limbo. But while the argument against embryonic stem-cell research seems at first glance strongly founded, further investigation ...

Insulin resistance leads to a number of metabolic and cellular abnormalities including endothelial dysfunction that increase the risk of vascular disease. Although it has been particularly challenging to study the genetic determinants that predispose to abnormal function of the endothelium in insulin-resistant states, the possibility of deriving endothelial cells from induced pluripotent stem cells generated from individuals with detailed clinical phenotyping, including accurate measurements of insulin resistance accompanied by multilevel omic data (eg, genetic and genomic characterization), has opened new avenues to study this relationship. Unfortunately, several technical barriers have hampered these efforts. In the present review, we summarize the current status of induced pluripotent stem cell-derived endothelial cells for modeling endothelial dysfunction associated with insulin resistance and discuss the challenges to overcoming these limitations. ...

TY - GEN. T1 - Multiresolution identification of germ layer components in teratomas derived from human and nonhuman primate embryonic stem cells. AU - Chebira, Amina. AU - Ozolek, John A.. AU - Castro, Carlos A.. AU - Jenkinson, William G.. AU - Gore, Mukta. AU - Bhagavatula, Ramamurthy. AU - Khaimovich, Irina. AU - Ormon, Shauna E.. AU - Navara, Christopher S.. AU - Sukhwani, Meena. AU - Orwig, Kyle E.. AU - Ben-Yehudah, Ahmi. AU - Schatten, Gerald. AU - Rohde, Gustavo K.. AU - Kovacevic, Jelena. PY - 2008/9/10. Y1 - 2008/9/10. N2 - We propose a system for identification of germ layer components in teratomas derived from human and nonhuman primate embryonic stem cells. Tissue regeneration and repair, drug testing and discovery, the cure of genetic and developmental syndromes all may rest on the understanding of the biology and behavior of embryonic stem (ES) cells. Within the field of stem cell biology, an ES cell is not considered an ES cell until it can produce a teratoma tumor (the gold ...

TY - JOUR. T1 - Paraquat toxicity in a mouse embryonic stem cell model. AU - Perla, Venu. AU - Perrin, Nancy A. AU - Greenlee, Anne R.. PY - 2008/3. Y1 - 2008/3. N2 - The objective of this in vitro study was to use a mouse embryonic stem (mES) cell model to better understand pesticide injury that may adversely affect early pregnancy and to evaluate an antioxidant intervention. Undifferentiated D3 mES cells were incubated 24 h with control, reference dose (RfD), no observed effect level (NOEL), or lowest observed effect level (LOEL) of paraquat, a commonly used, toxic agricultural herbicide. Pesticide effects were evaluated at 0 and 24 h using assays for cell proliferation, total reactive oxygen species (ROS), viability, and alkaline phosphatase activity. Compared to 0 h, cell proliferation increased significantly in the 24 h control treatment and was stalled in all paraquat dilutions tested. ROS production and percent necrotic and apoptotic cells were significantly increased at all paraquat ...

The mechanisms by which human embryonic stem cells (hESC) differentiate to endodermal lineage have not been extensively studied. Mathematical models can aid in the identification of mechanistic information. In this work we use a population-based modeling approach to understand the mechanism of endoderm induction in hESC, performed experimentally with exposure to Activin A and Activin A supplemented with growth factors (basic fibroblast growth factor (FGF2) and bone morphogenetic protein 4 (BMP4)). The differentiating cell population is analyzed daily for cellular growth, cell death, and expression of the endoderm proteins Sox17 and CXCR4. The stochastic model starts with a population of undifferentiated cells, wherefrom it evolves in time by assigning each cell a propensity to proliferate, die and differentiate using certain user defined rules. Twelve alternate mechanisms which might describe the observed dynamics were simulated, and an ensemble parameter estimation was performed on each ...

Abstract Human stem cell research is a new field with much promise, but progress towards a clinical setting has been complicated by scientific and ethical challenges. The most heated discussion over stem cell research has focused on the source of human embryonic stem cells (ESCs). Different views on the moral status of the human embryo have plagued all aspects of the debate (and decision-making). In 2006, a way of de-differentiating somatic cells to a pluripotent state was realised. The advent of these induced pluripotent stem cells (iPSCs) appeared to circumvent concerns over embryo destruction, and hence iPSCs have been touted as an ethical way forward. However, for the foreseeable future, scientific investigations involving iPSCs are likely to drive further embryo destruction. As a result, iPSC research is complicit in embryo destruction and is inextricably locked in to the moral status debate. I argue that a new approach is needed to deal with the serious uncertainties and indeterminate ...

Introduction. Contents 1. Introduction 2. Summary 3. What are stem cells? 3.1 Adult stem cells 3.2 Core blood stem cells 3.3 Embryonic stem cells 4. Potentially of embryonic stem cells 5. UK Stem Cell bank. 6. Controversial Issues 7. Bibliography 1. Introduction This is a report on stem cells and the stem cell bank The aim of this report to overview stem cell research, including stem cell banks and pitched at general readers of non scientific background. 2 Summary This report consists of brief information on what stem cells are and their sources, the UK Stem Cell Bank and the controversy surrounding embryonic stem cell research. The main point of this report is the potential for treatment of illness using embryonic stem cells. 3. What are Stem Cells? Stem cells are unspecialized (cells of no particular function) that reproduce themselves continually and under the right conditions develop from simple to more complex cells which are specialized to perform particular functions, this is termed cell ...

Pluripotency and the capability for self-renewal are essential characteristics of human embryonic stem cells (hESCs), which hold great potential as a cellular source for tissue replacement. Short cell cycle (15-16 h) compared to somatic cells is another property of hESCs. Efficient synchronization of hESCs at different cell cycle stages is important to elucidate the mechanistic link between cell cycle regulation and cell fate decision. This protocol describes how to establish synchronization of hESCs at different cell cycle stages.

The man who discovered induced pluripotent stem cells (iPSCs) has received the 2012 Nobel Prize for medicine. Dr. Shinya Yamanaka, a researcher from Kyoto University, developed a new process in 2006 that used four genes to reprogram skin cells in mice to behave like embryonic stem cells, which are pluripotent and thus capable of developing into any cell of the human body. In November 2007, Yamanaka and his team were able to create human iPSCs.. Yamanaka and the co-recipient, John B. Gurdon, received the prize owing to their discovery that mature, specialised cells can be reprogrammed to become immature cells capable of developing into all tissues of the body, according to a press release from the Nobel Assembly at Karolinska Institutet. By reprogramming human cells, scientists have created new opportunities to study diseases and develop methods for diagnosis and therapy.. The discovery means that embryonic stem cell research, which has just begun to undergo human clinical trials in Europe, ...

Yang, Z., Sui, L., Toh, W.S., Cao, T., Lee, E.H. (2009). Stage-dependent effect of TGF-1 on chondrogenic differentiation of human embryonic stem cells. Stem Cells and Development 18 (6) : 929-940. ScholarBank@NUS Repository. https://doi.org/10.1089/scd. ...

As with cultures of mouse ES cells, human ES cells begin to differentiate if they are removed from feeder layers and grown in suspension culture on a non-adherent surface. The human ES cells form embryoid bodies which, in the early stages, may be simple or cystic and filled with fluid. Although human embryoid bodies vary in their cellular content, many include cells that look like neurons and heart muscle cells [14, 25, 26].. After the human embryoid bodies form, they can be dissociated and replated in monolayer cultures which are then exposed to specific growth factors that influence further cell differentiation. Some growth factors induce cell types that would normally be derived from ectoderm in the embryo; these include retinoic acid, epidermal growth factor (EGF), bone morphogenic protein 4 (BMP4), and basic fibroblast growth factor (bFGF). Other growth factors, such as activin-A and transforming growth factor-beta 1 (TGF-ß1) trigger the differentiation of mesodermally derived cells. Two ...

A team of researchers from Scotland has used a novel 3D printing technique to arrange human embryonic stem cells (hESCs) for the very first time.

Enzymatically degradable poly(ethylene glycol) hydrogels for the 3D culture and release of human embryonic stem cell derived pancreatic precursor cell aggregates Journal Article ...

Since the successful isolation of mouse and human embryonic stem cells (ESCs) in the past decades, massive investigations have been conducted to dissect the pluripotency network that governs the ability of these cells to differentiate into all cell types. Beside the core Oct4-Sox2-Nanog circuitry, accumulating regulators, including transcription factors, epigenetic modifiers, microRNA and signaling molecules have also been found to play important roles in preserving pluripotency. Among the various regulations that orchestrate the cellular pluripotency program, transcriptional regulation is situated in the central position and appears to be dominant over other regulatory controls. In this review, we would like to summarize the recent advancements in the accumulating findings of new transcription factors that play a critical role in controlling both pluripotency network and ESC identity.

TY - JOUR. T1 - Parthenogenesis-derived multipotent stem cells adapted for tissue engineering applications. AU - Koh, Chester J.. AU - Delo, Dawn M.. AU - Lee, Jang Won. AU - Siddiqui, M. Minhaj. AU - Lanza, Robert P.. AU - Soker, Shay. AU - Yoo, James J.. AU - Atala, Anthony. PY - 2009/2/1. Y1 - 2009/2/1. N2 - Embryonic stem cells are envisioned as a viable source of pluripotent cells for use in regenerative medicine applications when donor tissue is not available. However, most current harvest techniques for embryonic stem cells require the destruction of embryos, which has led to significant political and ethical limitations on their usage. Parthenogenesis, the process by which an egg can develop into an embryo in the absence of sperm, may be a potential source of embryonic stem cells that may avoid some of the political and ethical concerns surrounding embryonic stem cells. Here we provide the technical aspects of embryonic stem cell isolation and expansion from the parthenogenetic ...

When I was doing the chapter 5 guided reading, I spent most of my time reading about stem cells. I wanted to know more about what they are able to do and the controversy in using embryonic stem cells. The main characteristics of stem cells, that you most likely know, are as follows: they can renew themselves and they can differentiate. These two characteristics are what most scientists agree on. There are also two different types of stem cells used for research. They are adult stem cells and embryonic stem cells. Adult stem cells are more likely to be rejected than embryonic stem cells, so embryonic stem cells seem better to research with. This is where the controversy comes in. When taking these cells from an embryo, scientists are killing the human child it would have been developed into. So far, these embryonic stem cells come from unwanted embryos. Politicians are trying to make this type of research illegal because they think it kills human life. Im not saying whether this is right or ...

Researchers have identified the gene which controls the critical self-renewal function of stem cells. Both adult and embryonic stem cells are able to repeatedly renew themselves, which allows them to be grown up in large numbers in the laboratory before being differentiated into specific tissue types. Although both types of stem cell - adult and embryonic - are able to do this, embryonic stem cells are able to differentiate into a broader range of cell types than adult stem cells. A team of scientists led by Boris Reizis of Columbia University Medical Center in New York, working on mouse cells, found that the gene Zfx controls self-renewal in both embryonic stem cells and in haematopoietic stem cells - adult blood precursor cells. The researchers published their findings in the journal Cell.. Other genes have previously been found that promote self renewal in embryonic cells - Oct4, Nanog and Sox2 - but Zfx is the first to control the same function in both adult and embryonic stem cells. Reizis ...

Charcot-Marie-Tooth disease line made from a never-frozen donated embryo.. The University of Michigans second human embryonic stem cell line has just been placed on the U.S. National Institutes of Healths registry, making the cells available for federally-funded research. It is the second of the stem cell lines derived at U-M to be placed on the registry.. The line, known as UM11-1PGD, was derived from a cluster of about 30 cells removed from a donated five-day-old embryo roughly the size of the period at the end of this sentence. That embryo was created for reproductive purposes, tested and found to be affected with a genetic disorder, deemed not suitable for implantation, and would therefore have otherwise been discarded when it was donated in 2011.. It carries the gene defect responsible for Charcot-Marie-Tooth disease, a hereditary neurological disorder characterized by a slowly progressive degeneration of the muscles in the foot, lower leg and hand. CMT, as it is known, is one of the most ...

The ethically fraught field of embryonic stem cell research received much attention in late 2007 when induced pluripotent cells stem cells (iPSCs) were derived from somatic cells manipulated with the Yamanaka factors- Oct3/4, Sox2, Klf4, c-Myc. These genes, which are highly expressed in embryonic stem cells, induce pluripotency and embryonic stem cell-like characteristics in human and mouse cells when overexpressed. Such cells hold promise for the field of regenerative medicine, and they dodge the controversy surrounding embryonic stem cells, since iPSCs can be derived from somatic cells, not embryos. Furthermore, they have demonstrated therapeutic benefit similar to that of embryonic stem cells. However, iPSCs are not free from drawbacks, and use could be limited in humans if viral transgenes are used in the induction process. This is especially true for oncogenes c-Myc and KLF4; reactivation of these in the host genome can lead to tumor formation. This has led researchers to examine the ...

Growth factors and transcription factors are well known to regulate pluripotent stem cells, but less is known about translational control in stem cells. Here, we use embryonic stem cells (ESCs) to investigate a connection between ESC growth factors and eIF2α-mediated translational control (eIF2α phosphorylation promotes protein expression from mRNAs with upstream open-reading frames, or uORFs). We find abundant phosphorylated P-eIF2α (P-eIF2α) in both pluripotent mouse and human ESCs, but little P-eIF2α in ESCs triggered to differentiate. We show that the growth factors LIF (leukemia inhibitory factor) and BMP4 (bone morphogenic protein 4) both maintain P-eIF2α in mESCs, but use distinct mechanisms: LIF inhibits an eIF2α phosphatase whereas BMP4 activates an eIF2α kinase. The mRNAs encoding the pluripotency factors Nanog and c-Myc possess uORFs while Oct4 mRNA does not. We find that salubrinal, a chemical that increases eIF2α phosphorylation, promotes Nanog and c-Myc expression, but not Oct4

Researchers first grew human embryonic stem cells in the lab in 1998, and policy on stem cells and human-animal chimeras followed two years later.. In August 2000, under President Bill Clinton, the NIH published a final rule that prohibited funding [r]esearch in which human pluripotent stem cells are combined with an animal embryo, along with providing the first guidelines for the kind of stem cell research that the agency would fund.. Since scientists hadnt yet developed induced pluripotent stem cells, this rule only applied to embryonic stem cells.. On Aug. 9, 2001, President George W. Bush limited the scope of stem cell research that could be federally funded to experiments using embryonic stem cell lines that had been derived prior to that day, among other limitations.. In November 2001, his administration also revoked the 2000 rule. But an NIH spokesperson told us, The policy that was in place under President Bush did not address human-animal chimeras specifically, and therefore did not ...

A concern raised some time ago is to determine whether the iPS cells produced from adult somatic cells have the specific characteristics of embryonic stem cells. If so, iPS cells could advantageously replace embryonic stem cells for experimental and clinical purposes, without the ethical difficu ...

Regulation of the extracellular matrix (ECM) plays an important functional role either in physiological or pathological conditions. The plasminogen activation (PA) system, comprising the uPA and tPA proteases and their inhibitor PAI-1, is one of the main suppliers of extracellular proteolytic activity contributing to tissue remodeling. Although its function in development is well documented, its precise role in mouse embryonic stem cell (ESC) differentiation in vitro is unknown. We found that the PA system components are expressed at very low levels in undifferentiated ESCs and that upon differentiation uPA activity is detected mainly transiently, whereas tPA activity and PAI-1 protein are maximum in well differentiated cells. Adipocyte formation by ESCs is inhibited by amiloride treatment, a specific uPA inhibitor. Likewise, ESCs expressing ectopic PAI-1 under the control of an inducible expression system display reduced adipogenic capacities after induction of the gene. Furthermore, the adipogenic

Recently, a handful of intergenic long noncoding RNAs (lncRNAs) have been shown to compete with mRNAs for binding to miRNAs and to contribute to development and disease. Beyond these reports, little is yet known of the extent and functional consequences of miRNA-mediated regulation of mRNA levels by lncRNAs. To gain further insight into lncRNA-mRNA miRNA-mediated crosstalk, we reanalyzed transcriptome-wide changes induced by the targeted knockdown of over 100 lncRNA transcripts in mouse embryonic stem cells (mESCs). We predicted that, on average, almost one-fifth of the transcript level changes induced by lncRNAs are dependent on miRNAs that are highly abundant in mESCs. We validated these findings experimentally by temporally profiling transcriptome-wide changes in gene expression following the loss of miRNA biogenesis in mESCs. Following the depletion of miRNAs, we found that |50% of lncRNAs and their miRNA-dependent mRNA targets were up-regulated coordinately, consistent with their interaction being

This unit describes a protocol for the isolation of cells from murine embryonic stem cells with hematopoietic stem cell activity, defined by the ability to reconstitute, long term, multiple lineages of the hematopoietic system of lethally irradiated mice. The protocol subjects hematopoietic progenitors specified in differentiating embryoid bodies to ectopic HoxB4 expression (delivered via retroviral infection), followed by coculture and expansion on OP9 stromal cells in the presence of hematopoietic cytokines for 10 days. The protocol results in the generation of hundreds of millions of cells that can rescue mice from lethal irradiation. Although little is known about the phenotype and frequency of the actual hematopoietic stem cell-like cell within the population of cells generated by this protocol, the protocol establishes a system in which these cells can be further studied and the results ultimately translated to the human system. McKinney-Freeman, Shannon L.; Naveiras, Olaia; Daley, George Q.

The current epidemic of obesity has caused a surge of interest in the study of adipose tissue formation. While major progress has been made in defining the molecular networks that control adipocyte terminal differentiation, the early steps of adipocyte development and the embryonic origin of this lineage remain largely unknown. Here we performed genome-wide analysis of gene expression during adipogenesis of mouse embryonic stem cells (ESCs). We then pursued comprehensive bioinformatic analyses, including de novo functional annotation and curation of the generated data within the context of biological pathways, to uncover novel biological functions associated with the early steps of adipocyte development. By combining in-depth gene regulation studies and in silico analysis of transcription factor binding site enrichment, we also provide insights into the transcriptional networks that might govern these early steps. This study supports several biological findings: firstly, adipocyte development in mouse

Rat ES cells were derived using 3I medium from E4.5 blastocysts. Rat embryonic fibroblast cells were derived form E14.5 embryos. To analyze the mechanism under the selfrenewal of rat ES cells, microarrays were used for the genome wide analysis of gene expressoin profiles in rat ES cells. Rat embryonic fibroblast cells and mouse ES cells were tested at same time as control. Our results from clustering analysis demonstrated that the gene expression profile of rat ES cells resembles mouse ES cells, but not REFs. Keyword: 3I medium; rat embryonic stem cells; mouse ES cells; rat embryonic fibroblast cells Rat ES cells were cultured in 3I medium; rat embryonic fibroblast cells were derived and cultured GMEM/10% FBS; mouse ES cells (C57/BL6)were cultured in GMEM/10% FBS added LIF and feeder cells were removed before RNA extraction. Three replicates each.

TY - JOUR. T1 - Gene conversion during vector insertion in embryonic stem cells. AU - Hasty, Edward P. AU - Rivera-pérez, Jaime. AU - Bradley, Allan. PY - 1995/6/11. Y1 - 1995/6/11. N2 - Recombination of an insertion vector Into Its chromosomal homologue is a conservative event in that both the chromosomal and the vector sequences are preserved. However, gene conversion may accompany homologous recombination of an Insertion vector. To examine gene conversion in more detail we have determined the targeting frequencies and the structure of the recomblnant alleles generated with a series of vectors which target the hprt gene in embryonic stem cells. We demonstrate that gene conversion of the introduced mutation does not significantly limit homologous recombination and that gene conversion occurs without a sequence specific bias for five different mutations. The frequency of the loss of a vector mutation and the gain of a chromosomal sequence is Inversely proportional to the distance between the ...

1. Volarevic V, Ljujic B, Stojkovic P. et al. Human stem cell research and regenerative medicine: present and future. Br Med Bull. 2011;99:155-168 2. Volarevic V, Erceg S, Bhattacharya SS. et al. Stem cell-based therapy for spinal cord injury. Cell Transplant. 2013;22:1309-1323 3. Turner L, Knoepfler P. Selling Stem Cells in the USA: Assessing the Direct-to-Consumer Industry. Cell Stem Cell. 2016;19:154-157 4. Smith AG. Embryo-derived stem cells: of mice and men. Annu Rev Cell Dev Biol. 2001;17:435-462 5. Zhang X, Stojkovic P, Przyborski S. et al. Derivation of human embryonic stem cells from developing and arrested embryos. Stem Cells. 2006;24:2669-2676 6. Thomson JA, Itskovitz-Eldor J, Shapiro SS. et al. Embryonic stem cell lines derived from human blastocysts. Science. 1998;28:1145114-1145117 7. Reubinoff BE, Pera MF, Fong CY. et al. Embryonic stem cell lines from human blastocysts: somatic differentiation in vitro. Nat Biotechnol. 2000;18:399-404 8. De Trizio E, Brennan CS. The business of ...

The complete relationship of embryonic stem cells (ESC) to cells in the mouse embryo remains controversial. advancement and is dropped after implantation. The regularity of deriving clonal ESC lines shows that all E4.5 epiblast cells may become ESC. We further display that ICM cells from early blastocysts can improvement to ERK-independence if given a particular laminin substrate. These results suggest that development from the epiblast coincides with competence for ERK-independent self-renewal and consequent propagation as ESC lines. Launch Mammalian preimplantation advancement establishes the founding cell people from the foetus and specifies two extraembryonic lineages. In mouse at throughout the 16-cell stage the external cells acquire trophectoderm identification; the inside cells form inner cell mass (ICM) which eventually segregates into primitive endoderm (PrE) and preimplantation epiblast. Epiblast cells exhibit pluripotency factors such as for example Oct4 Sox2 and Nanog1-5 whereas PrE ...

By Stuart P. Atkinson Current protocols for the differentiation of embryonic stem cells (ESC) to clinically relevant cell types are woefully inefficient with many millions or tens of millions of ESC used for each differentiation, only to yield small proportions of the desired cell type. This entails large scale culture and amplification of ESC, often over a large period of

Those of us who are opposed to the use of embryonic stem cells for research are routinely accused of being hard-hearted toward those whose maladies can be addressed with stem cell research. Of course, this is not the case. We fully support adult stem cell research, but even if adult stem cells prove problematic in some cases I would still not support embryonic stem cell research when the embryo must be destroyed to obtain them.. When we think about saving lives we must count the cost. Is relieving the symptoms of disease worth the cost of the lives of the weakest and most defenseless members of society? Treating embryos with careless disregard will lead to further abuses down the road.. One of the problems with embryonic stem cells was the possibility of immune rejection. To avoid this, many want to clone the affected individual and use the embryonic stem cells from the clone. But this treats the human embryo as a thing, a clump of cells. The basis of this ethic is strictly the end justifies ...

ImStem Biotechnology has successfully treated an animal model of multiple sclerosis (MS) using human embryonic stem cells (hESC) derived mesenchymal stem cells (MSCs), called hES-MSCs (…). Now researchers from ImStem, in collaboration with University of Connecticut Health Center (UCHC) and Advanced Cell Technology, Inc.(OTCBB:ACTC), have developed a novel therapy to treat MS with hES-MSCs.. They found that hES-MSCs are more effective in treating animal model of MS than MSCs from bone marrow of adult human donors (BM-MSC). This work is published in the June 5th 2014 online edition of Stem Cell Reports, the official journal of International Society for Stem Cell Research.. The beauty of the new hES-MSCs is their consistently high efficacy in MS model. This is a big surprise when we found that most BM-MSC lines show poor or no efficacy.. Additionally, BM-MSCs but not hES-MSCs express high level of IL-6, a proinflammatory cytokine can worsen the disease. This definitely adds more advantages to ...

Background Inhibition of glycogen synthase kinase-3 (GSK-3) improves the efficiency of embryonic stem (ES) cell derivation from various strains of mice and rats, as well as dramatically promotes ES cell self-renewal potential. β-catenin has been reported to be involved in the maintenance of self-renewal of ES cells through TCF dependent and independent pathway. But the intrinsic difference between ES cell lines from different species and strains has not been characterized. Here, we dissect the mechanism of GSK-3 inhibition by CHIR99021 in mouse ES cells from refractory mouse strains. Methodology/Principal Findings We found that CHIR99021, a GSK-3 specific inhibitor, promotes self-renewal of ES cells from recalcitrant C57BL/6 (B6) and BALB/c mouse strains through stabilization of β-catenin and c-Myc protein levels. Stabilized β-catenin promoted ES self-renewal through two mechanisms. First, β-catenin translocated into the nucleus to maintain stem cell pluripotency in a lymphoid-enhancing factor/T

With the introduction of just four factors researchers have successfu...The cells--which the researchers designate induced pluripotent stem c... Human embryonic stem cells might be used to treat a host of diseases...Those problems could be circumvented if pluripotent cells could be obt... We have demonstrated that pluripotent stem cells can be directly gene...,With,few,factors,,adult,cells,take,on,character,of,embryonic,stem,cells,biological,biology news articles,biology news today,latest biology news,current biology news,biology newsletters

The research, carried out by Dr Emmajayne Kingham at the University of Southampton in collaboration with the University of Glasgow and published in the journal Small, cultured human embryonic stem cells on to the surface of plastic materials and assessed their ability to change.. Scientists were able to use the nanotopographical patterns on the biomedical plastic to manipulate human embryonic stem cells towards bone cells. This was done without any chemical enhancement.. The materials, including the biomedical implantable material polycarbonate plastic, which is a versatile plastic used in things from bullet proof windows to CDs, offer an accessible and cheaper way of culturing human embryonic stem cells and presents new opportunities for future medical research in this area.. Professor Richard Oreffo, who led the University of Southampton team, explains: To generate bone cells for regenerative medicine and further medical research remains a significant challenge. However we have found that by ...

What are Stem Cells?. Stem cells are undifferentiated cells that have the potential to become specialized types of cells. Stem cells can be categorized as embryonic stem cells or adult stem cells. Embryonic stem cells are derived from a human fetus; there are many ethical concerns with embryonic stem cells, and these are not used in our practice.. Stem Cells are the seeds that grow into new muscle, tendon, ligament, cartilage and bone. These primitive cells are stored in our bodies in several places but they are very rich and easily accessible in bone marrow. In the case of PRP-Therapy, a few local stem cells can be triggered to help rebuild damaged tissue and more may trickle in over time. When Stem cells are actively harvested from bone marrow, concentrated in a centrifuge and mixed with a PRP injection, the results can be much more profound. This is because many thousands more cells are directly introduced to the injured area which can result in much faster and more extensive repair.. ...

Experiments on pigs have shown that secretion from human embryonic stem cells can minimize heart injury by reducing tissue death by 60 per cent, say researchers.

0080]Stem cells may be stem cells recently obtained from a donor, and in certain preferred embodiments, the stem cells are autologous stem cells. Stem cells may also be from an established stem cell line that is propagated in vitro. Suitable stem cells include embryonic stems and adult stem cells, whether totipotent, pluripotent, multipotent or of lesser developmental capacity. Stem cells are preferably derived from mammals, such as rodents (e.g. mouse or rat), primates (e.g. monkeys, chimpanzees or humans), pigs, and ruminants (e.g. cows, sheep and goats). Examples of mouse embryonic stem cells include: the JM1 ES cell line described in M. Qiu et al., Genes Dev 9, 2523 (1995), and the ROSA line described in G. Friedrich, P. Soriano, Genes Dev 5, 1513 (1991), and mouse ES cells described in U.S. Pat. No. 6,190,910. Many other mouse ES lines are available from Jackson Laboratories (Bar Harbor, Me.). Examples of human embryonic stem cells include those available through the following suppliers: ...