Search results for "differentiation"
showing 10 items of 1605 documents
Fourth-order relativistic corrections to electrical first-order properties using direct perturbation theory.
2011
In this work, we present relativistic corrections to first-order electrical properties obtained using fourth-order direct perturbation theory (DPT4) at the Hartree-Fock level. The considered properties, i.e., dipole moments and electrical-field gradients, have been calculated using numerical differentiation techniques based on a recently reported DPT4 code for energies [S. Stopkowicz and J. Gauss, J. Chem. Phys. 134, 064114 (2011)]. For the hydrogen halides HX, X=F, Cl, Br, I, and At, we study the convergence of the scalar-relativistic contributions by comparing the computed DPT corrections to results from spin-free Dirac-Hartree-Fock calculations. Furthermore, since in the DPT series spin-…
<i>In vitro</i> Modeling of Ryanodine Receptor 2 Dysfunction Using Human Induced Pluripotent Stem Cells
2011
Background/Aims: Induced pluripotent stem (iPS) cells generated from accessible adult cells of patients with genetic diseases open unprecedented opportunities for exploring the pathophysiology of human diseases in vitro. Catecholaminergic polymorphic ventricular tachycardia type 1 (CPVT1) is an inherited cardiac disorder that is caused by mutations in the cardiac ryanodine receptor type 2 gene (RYR2) and is characterized by stress-induced ventricular arrhythmia that can lead to sudden cardiac death in young individuals. The aim of this study was to generate iPS cells from a patient with CPVT1 and determine whether iPS cell-derived cardiomyocytes carrying patient specific RYR2 mutation recap…
Extracellular membrane vesicles as a mechanism of cell-to-cell communication: advantages and disadvantages.
2014
Microvesicles represent a newly identified mechanism of intercellular communication. Two different types of microvesicles have been identified: membrane-derived vesicles (EVs) and exosomes. EVs originate by direct budding from the plasma membrane, while exosomes arise from ectocytosis of multivesicular bodies. Recent attention has focused on the capacity of EVs to alter the phenotype of neighboring cells to make them resemble EV-producing cells. Stem cells are an abundant source of EVs, and the interaction between stem cells and the microenvironment (i.e., stem cell niche) plays a critical role in determining stem cell phenotype. The stem cell niche hypothesis predicts that stem cell number…
EXPRESSION OF PIPPIN PROTEIN AND CELL DIFFERENTIATION.
2008
We previously described a CSD-containing protein that seemed to bind mRNAs encoding histone variants and was present both in the nucleus and in the cytoplasm of specific populations of brain cells. Since other CSD-containing proteins have the ability to interact both with RNA and chromatin, we investigated the possibility that PIPPin binds to chromatin and indeed found that about 50% of nuclear PIPPin cannot be extracted from nuclei with salt and is instead extracted with acid, together with histones. Interestingly, a major fraction of chromatin-bound PIPPin is sumoylated and sumoylation seems to be controlled by thyroid hormones, both in vivo and in vitro. In order to study the functions o…
Spatial transcriptome of a germinal center plasmablastic burst hints at MYD88/CD79B mutants-enriched diffuse large B-cell lymphomas
2022
The GC reaction results in the selection of B cells acquiring effector Ig secreting ability by progressing toward plasmablastic differentiation. This transition is associated with exclusion from the GC microenvironment. The aberrant expansion of plasmablastic elements within the GC fringes configures an atypical condition, the biological characteristics of which have not been defined yet. We investigated the in situ immunophenotypical and transcriptional characteristics of a nonclonal germinotropic expansion of plasmablastic elements (GEx) occurring in the tonsil of a young patient. Compared to neighboring GC and perifollicular regions, the GEx showed a distinctive signature featuring key r…
Polycomb-like 2 Associates with PRC2 and Regulates Transcriptional Networks during Mouse Embryonic Stem Cell Self-Renewal and Differentiation
2010
SummaryPolycomb group (PcG) proteins are conserved epigenetic transcriptional repressors that control numerous developmental gene expression programs and have recently been implicated in modulating embryonic stem cell (ESC) fate. We identified the PcG protein PCL2 (polycomb-like 2) in a genome-wide screen for regulators of self-renewal and pluripotency and predicted that it would play an important role in mouse ESC-fate determination. Using multiple biochemical strategies, we provide evidence that PCL2 is a Polycomb Repressive Complex 2 (PRC2)-associated protein in mouse ESCs. Knockdown of Pcl2 in ESCs resulted in heightened self-renewal characteristics, defects in differentiation, and alte…
Upregulated acetylcholine synthesis during early differentiation in the embryonic stem cell line CGR8
2012
Stem cells are used to generate differentiated somatic cells including neuronal cells. Synthesis and release of acetylcholine, a neurotransmitter and widely expressed signaling molecule, were investigated in the murine embryonic stem cell line CGR8 during early differentiation, i.e. in the presence of leukemia inhibitory factor (LIF) to maintain pluripotency and in the absence of LIF to induce early differentiation. CGR8 cells express choline acetyltransferase (ChAT) as demonstrated by measurement of enzyme activity and substantial inhibition by bromoacetylcholine. Pluripotent CGR8 cells showed a ChAT activity of 250 pmol acetylcholine/mg/h, contained 1.1 pmol acetylcholine/10⁶ cells and re…
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…
Stem cells, cancer stem-like cells, and natural products.
2012
Somatic stem cells can be found in many rapidly regenerating tissues, e.g., the skin, gastrointestinal mucosa, and hematopoietic system, but are also present at low numbers in non-regenerative organs such as the heart and brain. In these organs, somatic stem cells aid in normal tissue homeostasis and repair after injury as well as self-renewal and the generation of specific progenitor cells during differentiation. Cancer stem-like cells are a small subpopulation of self-renewing cells that are able to proliferate upon appropriate stimulation and differentiate into heterogeneous lineages in tumors. Modulation of the behavior of normal tissue stem cells and cancer stem-like cells is an emergi…
In Vitro Generation of Pancreatic Endocrine Cells from Human Adult Fibroblast-Like Limbal Stem Cells
2012
Stem cells might provide unlimited supply of transplantable cells for β-cell replacement therapy in diabetes. The human limbus is a highly specialized region hosting a well-recognized population of epithelial stem cells, which sustain the continuous renewal of the cornea, and the recently identified stromal fibroblast-like stem cells (f-LSCs), with apparent broader plasticity. However, the lack of specific molecular markers for the identification of the multipotent limbal subpopulation has so far limited the investigation of their differentiation potential. In this study we show that the human limbus contains uncommitted cells that could be potentially harnessed for the treatment of diabete…