Here we show that platinum-resistant ovarian cancer cells also show reduced cholesterol biosynthesis, and mostly rely on uptake of exogenous cholesterol for their needs. Expression of FDPS and OSC, enzymes involved in cholesterol synthesis, are decreased both in drug-resistant cells and upon TRAP1 silencing, whereas the expression of LDL receptor, the main mediator of extracellular cholesterol uptake, is increased. Strikingly, treatment with different statins to inhibit cholesterol synthesis reduces cisplatin-induced apoptosis, whereas silencing of LIPG, an enzyme involved in lipid metabolism, increases sensitivity to the drug.
Cholesterol Homeostasis Modulates Platinum Sensitivity in Human Ovarian Cancer.
Specimen part, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Protein Syndesmos is a novel RNA-binding protein that regulates primary cilia formation.
Specimen part, Cell line
View SamplesWe conducted a genetic analysis of the developing temporo-mandibular joint (TMJ), a highly specialized synovial joint that permits movement and function of the mammalian jaw. First, we used laser capture microdissection to perform a genome-wide expression analysis of each of its developing components. The expression patterns of genes identified in this screen were examined in the TMJ and compared to other synovial joints including the shoulder joint and the hip joint. Striking differences were noted, indicating that the TMJ forms via a distinct molecular program. Several components of the Hedgehog (Hh) signaling pathway are among the genes identified in the screen, including Gli2, which is expressed specifically in the condyle and in the disk of the developing TMJ. We found that mice deficient in Gli2 display aberrant TMJ development such that the condyle loses its growth plate-like cellular organization and no disk is formed. In addition, we utilized a conditional strategy to remove activity of the Hh co-receptor encoded by Smo from chondrocyte progenitors. This cell autonomous loss of Hh signaling allows for disk formation, but the resulting structure fails to separate from the condyle. Thus, these experiments establish that Hh signaling acts at two distinct steps in disk morphogenesis, condyle initiation and disk-condyle separation, and provide a molecular framework for future studies of the TMJ.
Temporomandibular joint formation requires two distinct hedgehog-dependent steps.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
The effects of EBV transformation on gene expression levels and methylation profiles.
Sex, Specimen part, Subject
View SamplesEpstein-Barr virus (EBV)-transformed lymphoblastoid cell lines (LCLs) provide a conveniently accessible and renewable resource for functional studies in humans. The ability to accumulate multidimensional data pertaining to the same individual cell lines, from complete genomic sequences to detailed gene regulatory profiles, further enhances the utility of LCLs as a model system. A lingering concern, however, is that the changes associated with EBV transformation of LCLs reduce the usefulness of LCLs as a surrogate model for primary tissues. To evaluate the validity of this concern, we compared global gene expression profiles between CD20+ primary B cells and CD3+ primary T cells sampled from six individuals. Six independent replicates of transformed LCLs were derived from each sample.
The effects of EBV transformation on gene expression levels and methylation profiles.
Sex, Specimen part, Subject
View SamplesA sheet of choroid plexus epithelial cells extends into each cerebral ventricle and secretes signaling factors into the cerebrospinal fluid (CSF). To evaluate whether differences in the CSF proteome across ventricles arise, in part, from regional differences in choroid plexus gene expression, we defined the transcriptome of lateral ventricle (telencephalic) vs. fourth ventricle (hindbrain) choroid plexus. We find that positional identities of mouse, macaque, and human choroid plexi derive from gene expression domains that parallel their axial tissues of origin. We then show that molecular heterogeneity between telencephalic and hindbrain choroid plexi contributes to region-specific, age-dependent protein secretion in vitro. Transcriptome analysis of FACS-purified choroid plexus epithelial cells also predicts their cell type-specific secretome. Spatial domains with distinct protein expression profiles were observed within each choroid plexus. We propose that regional differences between choroid plexi contribute to dynamic signaling gradients across the mammalian cerebroventricular system. Overall design: Two-factor design with two levels per factor and n=2 biological replicates. Lateral (telencephalic) and fourth (hindbrain) choroid plexus samples are paired in that they are isolated from the same brains.
Spatially heterogeneous choroid plexus transcriptomes encode positional identity and contribute to regional CSF production.
No sample metadata fields
View SamplesInvestigating neuronal and photoreceptor regeneration in the retina of zebrafish has begun to yield insights into both the cellular and molecular means by which this lower vertebrate is able to repair its central nervous system. However, knowledge about the signaling molecules in the local microenvironment of a retinal injury and the transcriptional events they activate during neuronal death and regeneration is still lacking. To identify genes involved in photoreceptor regeneration, we combined light-induced photoreceptor lesions, laser-capture microdissection (LCM) of the outer nuclear layer (ONL) and analysis of gene expression to characterize transcriptional changes for cells in the ONL as photoreceptors die and are regenerated. Using this approach, we were able to characterize aspects of the molecular signature of injured and dying photoreceptors, cone photoreceptor progenitors and microglia within the ONL. We validated changes in gene expression and characterized the cellular expression for three novel, extracellular signaling molecules that we hypothesize are involved in regulating regenerative events in the retina.
Identification of the molecular signatures integral to regenerating photoreceptors in the retina of the zebra fish.
No sample metadata fields
View SamplesPlants regulate their time to flowering by gathering information from the environment. Photoperiod and temperature are among the most important environmental variables. Suboptimal, but not near-freezing, temperatures regulate flowering through the thermosensory pathway, which overlaps with the autonomous pathway. Here we show that ambient temperature regulates flowering by two genetically distinguishable pathways, one that requires TFL1 and another that requires ELF3. The delay in flowering time observed at lower temperatures was partially suppressed in single elf3 and tfl1 mutants, whereas double elf3 tfl1 mutants were insensitive to temperature. tfl1 mutations abolished the temperature response in cryptochrome mutants that are deficient in photoperiod perception, but not in phyB mutants that have a constitutive photoperiodic response. Contrary to tfl1, elf3 mutations were able to suppress the temperature response in phyB mutants, but not in cryptochrome mutants. The gene expression profile revealed that the tfl1 and elf3 effects are due to the activation of different sets of genes and identified CCA1 and SOC1/AGL20 as being important cross talk points. Finally, genome-wide gene expression analysis strongly suggests a general and complementary role for ELF3 and TFL1 in temperature signalling.
A complementary role for ELF3 and TFL1 in the regulation of flowering time by ambient temperature.
No sample metadata fields
View SamplesHuman Burkitt's lymphoma ST486 cells were transduced with non-target control shRNA lentiviral vectors, FOXM1 shRNA, and MYB shRNA lentiviral vectors. Total RNA was isolated 24h later. cRNA was produced with the standard one-step IVT protocol (Affymetix) and hybridized in U95Av2 gene chips (Affymetrix).
Correlating measurements across samples improves accuracy of large-scale expression profile experiments.
Cell line, Time
View SamplesIn the retina of adult teleosts, stem cells are sustained in two specialized niches: the ciliary marginal zone (CMZ) and the microenvironment surrounding adult Mller glia. Recently, Mller glia were identified as the regenerative stem cells in the teleost retina. Secreted signaling molecules that regulate neuronal regeneration in the retina are largely unknown. In a microarray screen to discover such factors, we identified midkine-b (mdkb). Midkine is a highly conserved heparin-binding growth factor with numerous biological functions. The zebrafish genome encodes two distinct midkine genes: mdka and mdkb. Here, we describe the cellular expression of mdka and mdkb during retinal development and the initial, proliferative phase of photoreceptor regeneration. The results show that in the embryonic and larval retina mdka and mdkb are expressed in stem cells, retinal progenitors and neurons in distinct patterns that suggest different functions for the two molecules. Following the selective death of photoreceptors in the adult, mdka and mdkb are co-expressed in horizontal cells and proliferating Mller glia and their neurogenic progeny. These data reveal that Mdka and Mdkb are signaling factors present in the retinal stem cell niches in both embryonic and mature retinas, and that their cellular expression is actively modulated during retinal development and regeneration.
Cellular expression of midkine-a and midkine-b during retinal development and photoreceptor regeneration in zebrafish.
No sample metadata fields
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