Search results for "embryonic stem cells"
showing 10 items of 72 documents
Mouse embryonic stem cells are hypersensitive to apoptosis triggered by the DNA damage O(6)-methylguanine due to high E2F1 regulated mismatch repair.
2007
Exposure of stem cells to genotoxins may lead to embryonic lethality or teratogenic effects. This can be prevented by efficient DNA repair or by eliminating genetically damaged cells. Using undifferentiated mouse embryonic stem (ES) cells as a pluripotent model system, we compared ES cells with differentiated cells, with regard to apoptosis induction by alkylating agents forming the highly mutagenic and killing DNA adduct O(6)-methylguanine. Upon treatment with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), ES cells undergo apoptosis at much higher frequency than differentiated cells, although they express a high level of the repair protein O(6)-methylguanine-DNA methyltransferase (MGMT). Apo…
Evolutionary conservation and function of the human embryonic stem cell specific miR-302/367 cluster
2015
miRNA clusters define a group of related miRNAs closely localized in the genome with an evolution that remains poorly understood. The miR-302/367 cluster represents a single polycistronic transcript that produces five precursor miRNAs. The cluster is highly expressed and essential for maintenance of human embryonic stem cells. We found the cluster to be highly conserved and present in most mammals. In primates, seed sequence and miRNA structure are conserved, but inter-precursor sequences are evolving. Insertions of new miRNAs, deletions of individual miRNAs, and a cluster duplication observed in different species suggest an actively evolving cluster. Core transcriptional machinery consisti…
Regulation of B cell homeostasis and activation by the tumor suppressor gene CYLD
2007
B cell homeostasis is regulated by multiple signaling processes, including nuclear factor-kappaB (NF-kappaB), BAFF-, and B cell receptor signaling. Conditional disruption of genes involved in these pathways has shed light on the mechanisms governing signaling from the cell surface to the nucleus. We describe a novel mouse strain that expresses solely and excessively a naturally occurring splice variant of CYLD (CYLD(ex7/8) mice), which is a deubiquitinating enzyme that is integral to NF-kappaB signaling. This shorter CYLD protein lacks the TRAF2 and NEMO binding sites present in full-length CYLD. A dramatic expansion of mature B lymphocyte populations in all peripheral lymphoid organs occur…
Computational identification of cell-specific variable regions in ChIP-seq data.
2019
ABSTRACT Chromatin immunoprecipitation followed by sequencing (ChIP-seq) is used to identify genome-wide DNA regions bound by proteins. Several sources of variation can affect the reproducibility of a particular ChIP-seq assay, which can lead to a misinterpretation of where the protein under investigation binds to the genome in a particular cell type. Given one ChIP-seq experiment with replicates, binding sites not observed in all the replicates will usually be interpreted as noise and discarded. However, the recent discovery of high-occupancy target (HOT) regions suggests that there are regions where binding of multiple transcription factors can be identified. To investigate these regions,…
miRNA Signature and Dicer Requirement during Human Endometrial Stromal Decidualization In Vitro
2012
Decidualization is a morphological and biochemical transformation of endometrial stromal fibroblast into differentiated decidual cells, which is critical for embryo implantation and pregnancy establishment. The complex regulatory networks have been elucidated at both the transcriptome and the proteome levels, however very little is known about the post-transcriptional regulation of this process. miRNAs regulate multiple physiological pathways and their de-regulation is associated with human disorders including gynaecological conditions such as endometriosis and preeclampsia. In this study we profile the miRNAs expression throughout human endometrial stromal (hESCs) decidualization and analy…
Systems level approach reveals the correlation of endoderm differentiation of mouse embryonic stem cells with specific microstructural cues of fibrin…
2014
Stem cells receive numerous cues from their associated substrate that help to govern their behaviour. However, identification of influential substrate characteristics poses difficulties because of their complex nature. In this study, we developed an integrated experimental and systems level modelling approach to investigate and identify specific substrate features influencing differentiation of mouse embryonic stem cells (mESCs) on a model fibrous substrate, fibrin. We synthesized a range of fibrin gels by varying fibrinogen and thrombin concentrations, which led to a range of substrate stiffness and microstructure. mESCs were cultured on each of these gels, and characterization of the diff…
Effect of LIF-withdrawal on acetylcholine synthesis in the embryonic stem cell line CGR8 is not mediated by STAT3, PI3Ks or cAMP/PKA pathways.
2015
Acetylcholine (ACh) acts as a local cellular signaling molecule and is widely expressed in nature, including mammalian cells and embryonic stem cells. The murine embryonic stem cell line CGR8 synthesizes and releases substantial amounts of ACh. Particularly during early differentiation - a period associated with multiple alterations in geno-/phenotype functions - synthesis and release of ACh are increased by 10-fold. In murine stem cells second messengers of the STAT-3, PI3K and cAMP/PKA pathways are involved in maintaining self-renewal and pluripotency. The present experiments were designed to test whether blockers of these signaling pathways enhance ACh cell content in the presence of LIF…
Stage-specific germ-cell marker genes are expressed in all mouse pluripotent cell types and emerge early during induced pluripotency.
2011
Embryonic stem cells (ESCs) generated from the in-vitro culture of blastocyst stage embryos are known as equivalent to blastocyst inner cell mass (ICM) in-vivo. Though several reports have shown the expression of germ cell/pre-meiotic (GC/PrM) markers in ESCs, their functional relevance for the pluripotency and germ line commitment are largely unknown. In the present study, we used mouse as a model system and systematically analyzed the RNA and protein expression of GC/PrM markers in ESCs and found them to be comparable to the expression of cultured pluripotent cells originated from the germ line. Further, siRNA knockdown experiments have demonstrated the parallel maintenance and independen…
Efficient differentiation of embryonic stem cells into mesodermal precursors by BMP, retinoic acid and Notch signalling
2012
The ability to direct differentiation of mouse embryonic stem (ES) cells into specific lineages not only provides new insights into the pathways that regulate lineage selection but also has translational applications, for example in drug discovery. We set out to develop a method of differentiating ES cells into mesodermal cells at high efficiency without first having to induce embryoid body formation. ES cells were plated on a feeder layer of PA6 cells, which have membrane-associated stromal-derived inducing activity (SDIA), the molecular basis of which is currently unknown. Stimulation of ES/PA6 co-cultures with Bone Morphogenetic Protein 4 (BMP4) both favoured self-renewal of ES cells and…
Cardiac Stem Cell Research: An Elephant in the Room?
2009
Heart disease is the leading cause of death in the industrialized world, and stem cell therapy seems to be a promising treatment for injured cardiac tissue. To reach this goal, the scientific community needs to find a good source of stem cells that can be used to obtain new myocardium in a very period range of time. Since there are many ethical and technical problems with using embryonic stem cells as a source of cells with cardiogenic potential, many laboratories have attempted to isolate potential cardiac stem cells from several tissues. The best candidates seem to be cardiac "progenitor" and/or "stem" cells, which can be isolated from subendocardial biopsies from the same patient or from…