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Results for “Embryonic Stem Cells”

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At least 19 recordsLinked to original sources

PubMed2006

A comparison study in the proteomic signatures of multipotent germline stem cells, embryonic stem cells, and germline stem cells.

Germline stem (GS) cells can only differentiate into germline cells, while multipotent germ stem (mGS) cells, like embryonic stem (ES) cells, can differentiate into various somatic cells and tissues. The proteomic profiles in GS and mGS cells were compared by two-dimensional gel electrophoresis. Ten down-regulated and 16 up-regulated proteins were differentially expressed in mGS cells in comparison to GS cells, and these proteomic characteristics were very much similar to those in ES cells indicating that multipotency of mGS and ES cells is based on a common molecular event(s). Protein identification by mass spectrometry revealed that these proteins were functionally involved in cell signaling, transcription factors, metabolism, and protein folding. The identified proteins in the present study may thus reveal its biological characteristics and functional property in self-renewal and multipotency.

Animals↗

PubMed2003

Cardiac specific differentiation of mouse embryonic stem cells.

Embryonic stem (ES) cells may represent an alternative source of functionally intact cardiomyocytes for the causal treatment of cardiovascular diseases. However, this requires cardiac-specific differentiation of stem cells and the selection of pure lineages consisting of early embryonic cardiomyocytes. Therefore, an understanding of the basic mechanisms of heart development is essential for selective differentiation of embryonic stem cells into cardiac cells. The development of cardiac cells from embryonic stem cells is regulated by several soluble factors and signalling molecules together with cardiac specific transcription factors such as the zinc-finger GATA proteins and Nkx-2.5. GATA-4 and Nkx-2.5 seem to be essential for heart development. The use of enhanced green fluorescent protein (EGFP) under the control of cardiac-specific promoters in combination with the ES cell system has allowed for the functional characterisation of cardiac precursor cells. Embryonic stem cell-derived cardiomyocytes developmentally express similar cardiac-specific proteins, ion channels and signalling molecules to that of adult cardiomyocytes. Furthermore, identification of growth factors and signalling molecules under cell culture conditions is crucial for the selective cardiac differentiation of embryonic stem cells. Therefore, serum-free culture conditions have to be established in order to examine the influence of different growth factors and signalling molecules on cardiac development and/or formation from ES cells. Although significant progress has been made in generating cardiac cell lineage by the combination of genetically manipulative methods with selective culture conditions for cell transplantation therapy, one of the remaining future challenges for transplantation in humans is the immunological rejection of the engrafted cardiomyocytes.

Animals↗

PubMed2006

Derivation of germ cells from embryonic stem cells.

Embryonic stem cells (ESCs), derivatives of cells of early mammalian embryos, have proven to be one of the most powerful tools in developmental and stem cell biology. When injected into embryos, ESCs can contribute to tissues derived from all three germ layers and to the germline. Prior studies have successfully shown that ESCs can recapitulate features of embryonic development by spontaneously forming somatic lineages in culture. Amazingly, recently it has been shown that mouse ESCs can also give rise to primordial germ cells (PGCs) in culture that are capable of undergoing meiosis and forming both male and female gametes. While the full potential of these ES-derived germ cells and gametes remains to be demonstrated, these discoveries provide a new approach for studying reproductive biology and medicine.

Animals↗

PubMed2001

Development of hematopoietic cells from embryonic stem cells.

Embryonic stem cells are pluripotent stem cells that can differentiate into all somatic cell lineages and germ lineage cells in vivo. In vitro differentiation capacity of the cells is rather limited compared with the in vivo pluripotency. However, differentiation into hematopoietic lineages is easily obtained, and it is a powerful tool to investigate hematopoietic development and differentiation. In this article, we describe a differentiation induction method that we established, the OP9 system, a unique method using the macrophage colony-stimulating factor-deficient stromal cell line OP9. The utility of the OP9 system includes hematopoietic development, differentiation, B-cell formation, osteoclast formation, and so on. The usefulness and limits of embryonic stem cell-derived hematopoietic cells in cell therapy are also discussed.

Animals↗

PubMed2002

Derivation and potential applications of human embryonic stem cells.

Embryonic stem cells are pluripotent cell lines that are derived from the blastocyst-stage early mammalian embryo. These unique cells are characterized by their capacity for prolonged undifferentiated proliferation in culture while maintaining the potential to differentiate into derivatives of all three germ layers. During in vitro differentiation, embryonic stem cells can develop into specialized somatic cells, including cardiomyocytes, and have been shown to recapitulate many processes of early embryonic development. The present review describes the derivation and unique properties of the recently described human embryonic stem cells as well as the properties of cardiomyocytes derived using this unique differentiating system. The possible applications of this system in several cardiac research areas, including developmental biology, functional genomics, pharmacological testing, cell therapy, and tissue engineering, are discussed. Because of their combined ability to proliferate indefinitely and to differentiate to mature tissue types, human embryonic stem cells can potentially provide an unlimited supply of cardiomyocytes for cell therapy procedures aiming to regenerate functional myocardium. However, many obstacles must still be overcome on the way to successful clinical utilization of these cells.

Animals↗

PubMed2006

Neural differentiation of embryonic stem cells induced by conditioned medium from neural stem cell.

Embryonic stem cells can proliferate indefinitely and are capable of differentiating into derivatives of all three embryonic germ layers in vitro, including the neural lineage. The main objective of this study is to test the effects of neural stem cell conditioned medium on the neural differentiation of mouse embryonic stem cells. When cultured in neural stem cell conditioned medium, mouse embryonic stem cells can form floating cell spheres composed of many nestin-positive cells. After trypsinization and growth on gelatin, these embryonic stem cell-derived neural progenitor cells can be expanded for more than 3 months without loss of neural progenitor characteristics. Both neuronal and glial cells can be readily generated from these cells under differentiation conditions. Thus, neural stem cell conditioned medium is a highly potent reagent for inducing the development of mouse embryonic stem cells into the neural lineage, especially neural progenitor cells.

Animals↗

PubMed2002

[Research on embryonic stem cells].

Embryonic stem cells are derived from inner cell mass of the preimplanted blastocyst or from primordial germ cells of the early embryos, with the capacity of unlimited growth and differentiation potential. Embryonic stem cells(ES cells) can differentiate into all kinds of cells and organs under proper condition. Due to this characteristics ES cells have the attractive prospect in basic research, transplantation and gene therapy.

Blastocyst↗

PubMed2004

[Advance in oriented differentiation of embryonic stem cell].

Embryonic stem cells have been the focus in tissue engineering, developmental biology, drug development and gene research. In this paper, the mechanisms, advances and applications of oriented differentiation of embryonic stem cells are reviewed for the promotion of researches on embryonic stem cells in future.

Animals↗

PubMed2005

[Advances in the study on molecular mechanism for maintaining the undifferentiated state of embryonic stem cells].

Embryonic stem cells (ES cells), that are derived from the inner cell mass (ICM) of early embryos at the blastocyst stage, have the ability of self-renewal and multiple differentiation capacity. Now ES cells have been extensively applied in basic research and clinical application. That ES cells maintain their undifferentiated state during culture is the prerequisite and basis of their application, and therefore it is necessary to elucidate the molecular mechanism. This review summarized the latest progress in the study on the molecular mechanism for maintaining the undifferentiated state of embryonic stem cells, and emphasized the function of differentiation suppression factors such as LIF, Oct-3/4 and Nanog.

Animals↗

PubMed2004

Regulated expression of pdx-1 promotes in vitro differentiation of insulin-producing cells from embryonic stem cells.

Embryonic stem (ES) cells can differentiate into many cell types. Recent reports have shown that ES cells can differentiate into insulin-producing cells. However, the differentiation is not efficient enough to produce insulin-secreting cells for future therapeutic use. Pdx-1, a homeodomain-containing transcription factor, is a crucial regulator for pancreatic development. We established an ES cell line in which exogenous pdx-1 expression was precisely regulated by the Tet-off system integrated into the ROSA26 locus. Using this cell line, we examined the effect of pdx-1 expression during in vitro differentiation via embryoid body formation. The results showed that pdx-1 expression clearly enhanced the expression of the insulin 2, somatostatin, Kir6.2, glucokinase, neurogenin3, p48, Pax6, PC2, and HNF6 genes in the resulting differentiated cells. Immunohistochemical examination also revealed that insulin was highly produced in most of the differentiated ES cells. Thus, exogenous expression of pdx-1 should provide a promising approach for efficiently producing insulin-secreting cells from human ES cells for future therapeutic use in diabetic patients.

Actins↗

PubMed1989

Germ-line transmission of a planned alteration made in a hypoxanthine phosphoribosyltransferase gene by homologous recombination in embryonic stem cells.

Embryonic stem cells (derived from 129/Ola mice) containing a mutant hypoxanthine phosphoribosyltransferase gene that had been corrected in vitro in a planned manner by homologous recombination were injected into blastocysts obtained from C57BL/6J mice. The injected blastocysts were introduced into pseudopregnant female mice to complete their development. Eleven surviving pups were obtained. Nine were chimeras: six males and three females. Two of the males transmitted the embryonic stem cell genome containing the alteration in the hypoxanthine phosphoribosyltransferase gene to their offspring at high frequencies. These experiments demonstrate that a preplanned alteration in a chosen gene can be made in the germ line of an experimental animal by homologous recombination in an embryonic stem cell.

Animals↗

PubMedDate not supplied

Molecular markers in embryonic stem cells.

Embryonic stem cells are pluripotent cells derived from mouse blastocysts, which have the capacity to differentiate in vitro into a wide variety of cell types. Based on this potential the embryonic stem cell test (EST) has been developed, which represents an assay system for the classification of compounds for their teratogenic potential, based on the morphological evaluation of contracting myocard cells compared to the cytotoxic effects on undifferentiated stem cells and adult 3T3 fibroblasts. To expand the EST, the quantitative expression of the alpha- and beta-myosin heavy chain (MHC) genes under the influence of test compounds was studied employing real-time TaqMan PCR analysis. The molecular evaluation of the MHC genes allows a higher sensitivity for the classification of substances and the transfer of the EST to the molecular level allows to start experimental procedures at day 9 of culture. Thus, the modulated EST holds promise as a new easily quantifiable in vitro screening assay in teratology.

3T3 Cells↗

PubMed1993

Type beta transforming growth factors and activins in differentiating embryonal carcinoma cells, embryonic stem cells and early embryonic development.

TGF beta was originally identified on the basis of its ability to induce phenotypic transformation of non-transformed target cells while activin was discovered as a gonadal protein. They later turned out to be related and both to have possibly crucial roles in the regulation of embryonic development. Here we review the circumstantial and direct evidence for this in the context of our own studies on their expression in and effects on murine EC and ES cells and mouse embryos. Their possible interaction in development is discussed.

Activin Receptors↗

PubMed2005

Nuclear reprogramming by human embryonic stem cells.

Embryonic stem cells have two unique properties. They are capable of indefinite self-renewal and, being pluripotent, they can differentiate into all possible cell types, including germ cells. A new study by Cowan et al. (2005) published in Science shows that human embryonic stem cells are able to reprogram the nuclei of fully differentiated human somatic cells, apparently conferring on them a pluripotent state.

Cell Nucleus↗

PubMed2007

Bone morphogenetic protein-mediated modulation of lineage diversification during neural differentiation of embryonic stem cells.

Embryonic stem cells (ES cells) can give rise to a broad spectrum of neural cell types. The biomedical application of ES cells will require detailed knowledge on the role of individual factors modulating fate specification during in vitro differentiation. Bone morphogenetic proteins (BMPs) are known to exert a multitude of diverse differentiation effects during embryonic development. Here, we show that exposure to BMP2 at distinct stages of neural ES cell differentiation can be used to promote specific cell lineages. During early ES cell differentiation, BMP2-mediated inhibition of neuroectodermal differentiation is associated with an increase in mesoderm and smooth muscle differentiation. In fibroblast growth factor 2-expanded ES cell-derived neural precursors, BMP2 supports the generation of neural crest phenotypes, and, within the neuronal lineage, promotes distinct subtypes of peripheral neurons, including cholinergic and autonomic phenotypes. BMP2 also exerts a density-dependent promotion of astrocyte differentiation at the expense of oligodendrocyte formation. Experiments involving inhibition of the serine threonine kinase FRAP support the notion that these effects are mediated via the JAK/STAT pathway. The preservation of diverse developmental BMP2 effects in differentiating ES cell cultures provides interesting prospects for the enrichment of distinct neural phenotypes in vitro.

Animals↗

PubMed2006

Derivation of clinical-grade human embryonic stem cells.

Embryonic stem cells proliferate in vitro while maintaining an undifferentiated state, and are capable of differentiating into most cell types under appropriate conditions. These properties imply great potential in the treatment of various diseases and disabilities. In fact, the first clinical trials with hESC for treating spinal cord injuries will begin next year. However, therapeutic application of human embryonic stem cell derivatives is compromised by the exposure of existing lines to animal and human components, with the subsequent risk of contamination with retroviruses and other pathogens, which can be transmitted to patients. The scientific community is striving to avoid the use of xenogeneic or allogeneic components in the process of derivation new hESC lines. This review summarizes attempts that have been made to avoid these contaminants and the breakthroughs achieved in the derivation of clinical-grade hESC that could be used for therapeutic purposes.

Animals↗

PubMed2005

Progress in studies on the induction and differentiation of embryonic stem cells.

Embryonic stem cells (ESCs), which are isolated from the inner cell mass of the blastocyst stage embryo, have the potential to give rise to an entire organism and to generate every body cell type. Much improvement has been made in the field of induction and differentiation of ESCs during the last two years, such as the ESCs differentiation into germ cells (2003) and the cloning of human ESCs (2004), both of which were chosen respectively as one of the top ten achievements evaluated by academic journals. Great attention was also paid to the research of the new genes which could maintain ESCs in the undifferentiated state and the research of the induction and differentiation of ESCs.

Animals↗

PubMed2005

High density cultures of embryonic stem cells.

Embryonic stem cells (ESC) have the unique ability to differentiate into a variety of tissue types. However, the realization of regenerative medicine will require the production of large quantities of ESC which subsequently have to be differentiated into the final phenotype. Thus, we sought to develop a simple and scaleable bioprocess to increase densities of ESC to achieve this goal. Using mouse embryonic stem cells (mESC) as a model, by combining automated feeding and culture of mESC on petriperm dishes, cell densities were enhanced up to 6.4 x 10(6) cells/cm2 compared to conventional petri dish culture which only reached 0.2 to 1.4 x 10(6) cells/cm2. It was found that mESC from all experiments maintained excellent viability, pluripotency, and genetic stability after growing for 6 days in petriperm cultures with automated feeding. The expression of Oct-4 transcription factor was observed in all cultures, mESC formed embryoid bodies in differentiated cultures and teratomas in SCID mice, confirming their pluripotency, and karyotype of the cultures was normal. This culture method was stable for routine passaging and a second mESC cell line was shown to perform in a similar manner on petriperm with automated feeding. This work represents an important step towards achieving high density cultures of ESC.

Alkaline Phosphatase↗