No description.
Mili and Miwi target RNA repertoire reveals piRNA biogenesis and function of Miwi in spermiogenesis.
Cell line, Subject
View SamplesMicroRNAs inhibit gene expression by recruiting the RNA-induced silencing complex (RISC) to mRNAs in a process termed RNA interference (RNAi). While it is generally accepted that RNAi modulates gene expression pervasively, the number of mRNAs bound and repressed by miRNAs in vivo in individual cell types remains unknown, with estimates ranging from a few hundred genes to many thousands. We examined microRNA activities in primary cells by combining genetic loss of function with RNA-sequencing, quantitative proteomics and High-Throughput Sequencing of RNA isolated by Crosslinking Immunoprecipitation (HITS-CLIP), focusing on miR-144/451, the most highly expressed microRNA locus during red blood cell (RBC) formation. We show that Argonaute (Ago) protein binds over one thousand different mRNAs in a miR-144/451-dependent manner, accounting for one third of all Ago-bound mRNAs. However, only about 100 mRNAs are stabilized in RBC precursors after ablation of the miR-144/451 locus. Thus, Ago-miRNA complexes destabilize only a small subset of bound mRNAs, probably no more than a few hundred in erythroblasts under physiological conditions. Our integrated approach identified more than 50 new miR-144/451 target mRNAs, including Cox10, which facilitates assembly of the mitochondrial cytochrome c oxidase (COX) electron transport complex. Loss of miR-144/451 resulted in increased Cox10 expression, accumulation of the COX complex, and increased mitochondrial membrane potential with no change in mitochondrial mass. Thus, miR-144/451 represses mitochondrial respiration during erythropoiesis by inhibiting Cox10. Overall design: HITS-CLIP analysis of 3 WT mice fetal livers vs 3 miR-144/451 KO mice fetal livers
Regulation of gene expression by miR-144/451 during mouse erythropoiesis.
Cell line, Subject
View SamplesType 2 diabetes mellitus (T2DM) is a multi-factorial disease characterized by the inability of beta-cells in the endocrine pancreas to produce sufficient amounts of insulin to overcome insulin resistance in peripheral tissue. To investigate the function of miRNAs in T2DM, we sequenced the small RNAs of human islets cells from diabetic and non-diabetic organ donors and identified a cluster of miRNAs in an imprinted locus on human chromosome 14 to be dramatically down-regulated in T2DM islets. These miRNAs are highly and specifically expressed in human beta-cells. The down-regulation of this imprinted locus strongly correlates with increased methylation of its promoter in T2DM islets, providing evidence for an epigenetic modification that contributes to the pathogenesis of T2DM. Targets of the Chr 14q32 cluster of miRNAs were identified by high-throughput sequencing of cross-linked and immunoprecipitated RNA (HITS-CLIP) of Argonaute. We have also identified a unique class of sequences, termed chimeric reads, that represent an in vivo ligation of miRNAs and their targets while in complex with Argonaute, and which allow for the direct identification of miRNA:target relationships in vivo. Overall design: There are three experiments in this submission. All are in human islets or islet cell types. The first is a comparison of miRNA levels in sorted alpha versus beta cells. There is one replicate for this experiment. The second experiment is to measure the expression of miRNAs in whole islets as a function of glucose levels. There are three levels and one replicate for each condition. The third exeriment is a comparison of whole islets taken from human donors that were suspected/confirmed Type 2 diabetic or considered controls. There are 3 controls and 4 T2D samples.
Epigenetic regulation of the DLK1-MEG3 microRNA cluster in human type 2 diabetic islets.
No sample metadata fields
View SamplesType 2 diabetes mellitus (T2DM) is a complex disease characterized by the inability of the insulin-producing ß-cells in the endocrine pancreas to overcome insulin resistance in peripheral tissues. To determine if microRNAs are involved in the pathogenesis of human T2DM, we sequenced the small RNAs of human islets from diabetic and non-diabetic organ donors. We identified a cluster of miRNAs in an imprinted locus on human chromosome 14q32 that is highly and specifically expressed in human ß-cells and dramatically down-regulated in islets from T2DM organ donors. The down-regulation of this locus strongly correlates with hyper-methylation of its promoter. Using HITS-CLIP for the essential RISC-component Argonaute, we identified disease-relevant targets of the chromosome 14q32 microRNAs, such as IAPP and TP53INP1 that cause increased ß-cell apoptosis upon over-expression in human islets. Our results support a role for microRNAs and their epigenetic control by DNA methylation in the pathogenesis of T2DM. Overall design: Identification of miRNA-target interaction in human islets using HITS-CLIP, one mRNA library and one miRNA library
Epigenetic regulation of the DLK1-MEG3 microRNA cluster in human type 2 diabetic islets.
No sample metadata fields
View SamplesTargets of Retinoic Acid (RA) were identified in primary human epidermal keratinocytes grown in the presence or absence of all-trans retinoic acid for 1, 4, 24, 48 and 72 hours. Targets of Thyroid Hormone (T3) were identified in primary human epidermal keratinocytes grown in the presence or absence of the hormone; same controls as for RA.
Retinoid-responsive transcriptional changes in epidermal keratinocytes.
Specimen part
View SamplesBackground. The cAMP Response Element Binding Protein, CREB, is a transcription factor that regulates cell proliferation, differentiation, and survival in several model systems, including neuronal and hematopoietic cells. We demonstrated that CREB is overexpressed in acute myeloid and leukemia cells compared to normal hematopoietic stem cells. CREB knockdown inhibits leukemic cell proliferation in vitro and in vivo, but does not affect long-term hematopoietic reconstitution. Therefore, we propose CREB to be a potential target for therapy. To understand downstream pathways regulating CREB, we performed expression profiling with RNA from the K562 myeloid leukemia cell line.
Expression profile of CREB knockdown in myeloid leukemia cells.
No sample metadata fields
View SamplesGlucocorticoids (GCs) have a long history of use as therapeutic agents for numerous skin diseases. Surprisingly, their specific molecular effects are largely unknown. To characterize GC action in epidermis, we compared the transcriptional profiles of primary human keratinocytes untreated and treated with dexamethasone (DEX) for 1, 4, 24, 48 and 72 hours using large-scale microarray analyses. The majority of genes were found regulated only after 24 hours and remained regulated throughout the treatment. In addition to expected anti-inflammatory genes, we found that GCs regulate cell fate, tissue remodeling, cell motility, differentiation and metabolism. GCs not only effectively block signaling by TNF-alpha and IL-1 but also by IFN-gamma, which was not previously known. Specifically, GCs suppress the expression of essentially all IFN-gamma-regulated genes, including IFN-gamma receptor and STAT-1. GCs also block STAT-1 activation and nuclear translocation. Unexpectedly, GCs have anti-apoptotic effects in keratinocytes by inducing the expression of anti-apoptotic and repressing pro-apoptotic genes. Consequently, GCs treatment blocked UV-induced apoptosis of keratinocytes. GCs have a profound effect on wound healing by inhibiting cell motility and the expression of pro-angiogenic factor VEGF. They play an important role in tissue remodeling and scar formation by suppressing the expression of TGF-beta-1 and -2, MMP1, 2, 9 and 10 and inducing TIMP-2. Finally, GCs promote terminal stages of epidermal differentiation while simultaneously inhibiting the early stages. These results provide new insights into the beneficial and adverse effects of GCs in epidermis, defining the participating genes and mechanisms that coordinate the cellular responses important for GC-based therapies.
Novel genomic effects of glucocorticoids in epidermal keratinocytes: inhibition of apoptosis, interferon-gamma pathway, and wound healing along with promotion of terminal differentiation.
Specimen part, Treatment
View SamplesNumerous mechanisms to support cells under conditions of transient nutrient starvation have been described. The tumor suppressor protein p53 can contribute to the adaptation of cells to metabolic stress through various mechanisms that may help cancer cell survival in nutrient limiting conditions. We show here that p53 helps cancer cells to survive glutamine starvation by promoting the expression of SLC1A3, an aspartate/glutamate transporter that allows the utilization of aspartate to support cells in the absence of extracellular glutamine. Under glutamine deprivation, SLC1A3 expression maintains electron transport chain and tricarboxylic acid cycle activity, promoting de novo glutamate, glutamine and nucleotide synthesis to rescue cell viability. Tumor cells with high levels of SLC1A3 expression are resistant to glutamine starvation and SLC1A3 depletion retards the growth of these cells in vitro and in vivo, suggesting a therapeutic potential for SLC1A3 inhibition. Overall design: We quantify transcription via high throughput RNA sequencing in HCT116 cells (WT1 and WT2 clones) grown in complete medium (CM) or in glutamine-free medium (GD) for 48 hours.
A Role for p53 in the Adaptation to Glutamine Starvation through the Expression of SLC1A3.
Specimen part, Cell line, Subject
View SamplesBesides symptoms caused by central nervous system (CNS) lesions, the majority of patients with multiple sclerosis (MS) also exhibit gastrointestinal dysfunction that has frequently been noted, but was not directly linked to the autoimmune etiology of the disease.We studied the enteric nervous system (ENS) in a murine model of MS by histology and electron microscopy. Serum IgG against enteric neurons and enteroglia was measured by ELISA and binding to the ENS was confirmed by immunohistochemistry. Target antigens were identified by mass spectrometry. Gastrointestinal dysfunction was determined by measuring dye transit time. RNA expression profiling was conducted with small intestines of MP4-immunized and control-immunized mice. Data from the mouse model were confirmed in MS patients by immunohistochemistry of the ENS in bowel resectates. In addition, ELISA was performed on plasma samples to detect antibodies against four specific target antigens as identified in the mouse model. ENS degeneration was evident already before the onset of clinical disease in the mouse model. Pathology was predominantly antibody-mediated and caused a significant decrease in gastrointestinal transit, which was associated with severe gliosis of the ENS. Unlike the dense infiltrates that developed in the perivascular compartments of the CNS of MP4-immunized mice, the infiltrates in the ENS consisted of single cells scattered throughout the tissue. RNA expression profiling could support these results, as the expression of inflammatory markers in the small intestine was similar between MP4-immunized and HEL-immunized mice. We identified four specific target antigens derived from enteric neurons and/or enteroglia. Antibodies against all four target antigens were present in MS patients. MS patients also showed gliosis and signs of ENS degeneration in the small intestine. For the first time, this study establishes a pathomechanistic link between the well-established autoimmune attack on the CNS and the ENS in MS. The presence of ENS pathology prior to CNS degeneration introduces entirely novel ways to explain MS etiology and immunopathogenesis.
The enteric nervous system is a potential autoimmune target in multiple sclerosis.
No sample metadata fields
View SamplesWe compared different mouse cancer cell lines to identify their unique cell signatures.
Mutant KRAS promotes malignant pleural effusion formation.
Specimen part, Cell line
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