Search results for "Embryonic Stem Cell"

Human Embryonic Stem Cell-Derived and Fetal Macrophages Exhibit Mainly Features of Alternative (M2) Polarization.

2009

Abstract Abstract 4598 Monocyte heterogeneity has long been recognized and 2 functional subsets of human monocytes that exert specific roles in homeostasis and inflammation in vivo, M1 and M2 monocytes, has been described. The different monocyte subsets seem to reflect developmental stages with distinct physiological roles but few is known whether the macrophage diversity arises in early ontogeny. Human embryonic stem cells (hESC) provide an unique model for in vitro studies of the early ontogeny of the hematopoietic system. Human embryonic monocytes were obtained from embryoid bodies cultured for 3 weeks in the presence of BMP4, VEGF and a mixture of hematopoietic cytokines. The sorted CD1…

Reverse engineering a mouse embryonic stem cell-specific transcriptional network reveals a new modulator of neuronal differentiation

2012

Gene expression profiles can be used to infer previously unknown transcriptional regulatory interaction among thousands of genes, via systems biology 'reverse engineering' approaches. We 'reverse engineered' an embryonic stem (ES)-specific transcriptional network from 171 gene expression profiles, measured in ES cells, to identify master regulators of gene expression ('hubs'). We discovered that E130012A19Rik (E13), highly expressed in mouse ES cells as compared with differentiated cells, was a central 'hub' of the network. We demonstrated that E13 is a protein-coding gene implicated in regulating the commitment towards the different neuronal subtypes and glia cells. The overexpression and …

Maternal Oct-4 is a potential key regulator of the developmental competence of mouse oocytes

2008

Abstract Background The maternal contribution of transcripts and proteins supplied to the zygote is crucial for the progression from a gametic to an embryonic control of preimplantation development. Here we compared the transcriptional profiles of two types of mouse MII oocytes, one which is developmentally competent (MIISN oocyte), the other that ceases development at the 2-cell stage (MIINSN oocyte), with the aim of identifying genes and gene expression networks whose misregulated expression would contribute to a reduced developmental competence. Results We report that: 1) the transcription factor Oct-4 is absent in MIINSN oocytes, accounting for 2) the down-regulation of Stella, a matern…

Possible clinical usefulness of embryonic stem cells

2012

Abstract Are embryonic stem cells being used for therapeutic purposes? The aim of this short report is to review to what extent are embryonic stem cells currently used for therapeutic purposes. To the best of our knowledge, only four clinical trials have been authorised so far to use human embryonic stem cells for therapeutic purposes; two of these are included in the ClinicalTrials.gov data base, and the other two, the study sponsored by Geron and the last one initiated by Advanced Cell Technology in the United Kingdom, are not. But, in addition, Geron withdrew the clinical trial which had been originally proposed by the company itself. This brief review focuses the debate on the use of em…

Burst analysis tool for developing neuronal networks exhibiting highly varying action potential dynamics

2012

In this paper we propose a firing statistics based neuronal network burst detection algorithm for neuronal networks exhibiting highly variable action potential dynamics. Electrical activity of neuronal networks is generally analyzed by the occurrences of spikes and bursts both in time and space. Commonly accepted analysis tools employ burst detection algorithms based on predefined criteria. However, maturing neuronal networks, such as those originating from human embryonic stem cells (hESC), exhibit highly variable network structure and time-varying dynamics. To explore the developing burst/spike activities of such networks, we propose a burst detection algorithm which utilizes the firing s…

New perspectives in medically assisted procreation.

2008

Embryonic stem cell differentiation studied by FT-IR spectroscopy

2007

We propose, here, an FT-IR method to monitor the spontaneous differentiation of murine embryonic stem (ES) cells in their early development. Principal component analysis and subsequent linear discriminant analysis enabled us to segregate stem cell spectra into separate clusters corresponding to different differentiation times - and to identify the most significant spectral changes during differentiation. Between days 4 to 7 of differentiation, these spectral changes in the protein amide I band (1700-1600 cm(-1)) and in the nucleic acid absorption region (1050-850 cm(-1)) indicated that mRNA translation was taking place and that specific proteins were produced, reflecting the appearance of a…

T-CELL-MEDIATED CYTOLYSIS : FROM THE LYSIS OF H-2 NEGATIVE TARGET CELLS TO THE INDUCTIVE EFFECT OF XENOGENEIC SERUM

1979

Publisher Summary This chapter describes the results of a series of experiments. In the first series, evidence was found in favor of some specificity of cytolysis against embryonic antigens at the surface of the F9 cells. In a second series of experiments, it was found that P815 and EL4 cells were lysed. From a systematic investigation of the parameters of this system, two facts emerged. F9 cells were not necessary during the in vitro boost incubation. There was some preferential lysis of targets having the same H-2 as the mice receiving the H-2-less F9. For instance, if F9 cells were injected into B1O mice, and after 2–3 weeks, the spleen cells were incubated for 5 days in conventional tis…

Homeobox-containing gene transiently expressed in a spatially restricted pattern in the early sea urchin embryo

1995

In the sea urchin embryo, the lineage founder cells whose polyclonal progenies will give rise to five different territories are segregated at the sixth division. To investigate the mechanisms by which the fates of embryonic cells are first established, we looked for temporal and spatial expression of homeobox genes in the very early cleavage embryos. We report evidence that PlHbox12, a paired homeobox-containing gene, is expressed in the embryo from the 4-cell stage. The abundance of the transcripts reaches its maximum when the embryo has been divided into the five polyclonal territories--namely at the 64-cell stage--and it abruptly declines at later stages of development. Blastomere dissoc…

Studies on heat shock proteins in sea urchin development

1999

Work on stress proteins in sea urchin embryos carried out over the last 20 years is reviewed and the following major results are described. Entire sea urchin embryos, if subjected to a rise in temperature at any postblastular stage undergo a wave of heat shock protein (hsp) synthesis and survive. If subjected to the same rise between fertilization and blastula formation, they are not yet able to synthesize hsp and die. Four clones coding for the major hsp, hsp70, have been isolated and sequenced; evidence for the existence of a heat shock factor has been provided, and a mechanism for the developmental regulation of hsp synthesis discussed. Intra- embryonic and intracellular hsp location has…