Background: Ion channels are key determinants for the function of excitable cells but little is known about their role and involvement during cardiac development. Earlier work identified Ca2+-activated potassium channels of small and intermediate conductance (SKCas) as important regulators of neural stem cell fate. Here, we have investigated their impact on the differentiation of pluripotent cells towards the cardiac lineage. Methods and Results: We have applied the SKCa-activator EBIO on embryonic stem cells and identified this particular ion channel family as a new critical target involved in the generation of cardiac pacemaker-like cells: SKCa-activation led to rapid remodeling of the actin cytoskeleton, inhibition of proliferation, induction of differentiation and diminished teratoma formation. Time-restricted SKCa-activation induced cardiac mesoderm and commitment to the cardiac lineage as shown by gene regulation, protein and functional electrophysiological studies. In addition, the differentiation into cardiomyocytes was modulated in a qualitative fashion, resulting in a strong enrichment of pacemaker-like cells. This was accompanied by induction of the sino-atrial gene program and in parallel by a loss of the chamber-specific myocardium. In addition, SKCa activity induced activation of the Ras-Mek-Erk signaling cascade, a signaling pathway involved in the EBIO-induced effects.
Modulation of calcium-activated potassium channels induces cardiogenesis of pluripotent stem cells and enrichment of pacemaker-like cells.
Specimen part, Cell line
View SamplesThe goal of this study was to examine whether immune responses to Plasmodium chabaudi infection differ between the sexes and are altered by the presence of gonadal steroids. Gonadally-intact males were more likely than intact females to die following P. chabaudi infection, exhibit slower recovery from infection-associated weight loss, hypothermia, and anemia, have reduced IFN-associated gene expression and IFN production during peak parasitemia, and produce less antibody during the recovery phase of infection. Gonadectomy of male and female mice altered these sex-associated differences, suggesting that sex steroid hormone, in particular androgens and estrogens, may modulate immune responses to infection.
Involvement of gonadal steroids and gamma interferon in sex differences in response to blood-stage malaria infection.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Large-scale hypomethylated blocks associated with Epstein-Barr virus-induced B-cell immortalization.
Specimen part, Time
View SamplesTo determine what DNA methylation and gene expression changes occur following EBV transformation. B-cells were isolated from 3 donors. Resting, CD40 activated and EBV transfromed cells from each donor was analyzed. Each sample was assayed using Affymetrix expression arrays and whole genome bisulfite sequenicng. Additional time points during transformation and activation were sequenced as well, but not assayed for expression.
Large-scale hypomethylated blocks associated with Epstein-Barr virus-induced B-cell immortalization.
Specimen part
View SamplesIdentification of genetic/cytogenetic alterations and differentially expressed cellular genes in HPV16 E6, E7 and E6/E7 positive human foreskin keratinocytes
Complementation of non-tumorigenicity of HPV18-positive cervical carcinoma cells involves differential mRNA expression of cellular genes including potential tumor suppressor genes on chromosome 11q13.
No sample metadata fields
View SamplesIdentification of genes differentially expressed in tumorigenic compared to non-tumorigenic, HPV18 positive cells
Complementation of non-tumorigenicity of HPV18-positive cervical carcinoma cells involves differential mRNA expression of cellular genes including potential tumor suppressor genes on chromosome 11q13.
No sample metadata fields
View SamplesWe used microarrays to detail the global gene expression changes following RNAi knock-down of dTip60 in Drosophila SL2 cells
Widespread regulation of gene expression in the Drosophila genome by the histone acetyltransferase dTip60.
Cell line
View SamplesCircadian clocks are cell-autonomous oscillators regulating daily rhythms in a wide range of physiological, metabolic and behavioral processes. Conversely, metabolic signals such as redox state, NAD+/NADH and AMP/ADP ratios or heme feed back to and modulate circadian mechanisms to optimize energy utilization across the 24-hour cycle. We show that the signaling molecule carbon monoxide (CO) generated by rhythmic heme degradation is required for normal circadian rhythms as well as circadian metabolic outputs.
Reciprocal regulation of carbon monoxide metabolism and the circadian clock.
Sex, Specimen part
View SamplesWe used microarrays to detail the global gene expression changes following apical infection of porcine choroid plexus epithelial cells (PCPEC) with Streptococcus suis (S. suis)
In vitro transcriptome analysis of porcine choroid plexus epithelial cells in response to Streptococcus suis: release of pro-inflammatory cytokines and chemokines.
Specimen part
View SamplesPerturbation of the gated-synchrony system in yeast with phenelzine, an antidepressant drug used in the treatment of affective disorders in humans, leads to a rapid lengthening in the period of the genome-wide transcriptional oscillation. The effect is a concerted, genome-scale change in expression that is first seen in genes maximally expressed in the late-reductive phase of the cycle, doubling the length of the reductive phase within two cycles after treatment. Clustering of genes based on their temporal patterns of expression yielded just three super clusters whose trajectories through time could then be mapped into a simple 3D figure. In contrast to transcripts in the late-reductive phase, most transcripts do not show transients in expression relative to others in their temporal cluster but change their period in a concerted fashion. Mapping the trajectories of the transcripts into low-dimensional surfaces that can be represented by simple systems of differential equations provides a readily testable model of the dynamic architecture of phenotype. In this system, period doubling may be a preferred pathway for phenotypic change. As a practical matter, low-amplitude, genome-wide oscillations, a ubiquitous but often unrecognized attribute of phenotype, could be a source of seemingly intractable biological noise in microarray studies.
A rapid genome-scale response of the transcriptional oscillator to perturbation reveals a period-doubling path to phenotypic change.
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