We generated whole genome expression profiles from a homogeneous population of purified pacemaker neurons (ventral Lateral Neurons, LNvs) from wild type and clock mutant Drosophila. The study identifes a group of genes whose expression is highly enriched in LNvs compared to other neurons; and a second group of genes rhythmically expressed in LNvs in a clock-dependent manner.
A mechanism for circadian control of pacemaker neuron excitability.
Specimen part
View SamplesWe used microarrays to reveal the global expression profiles of young and old whole lateral ventricle choroid plexus tissue.
Age-Dependent Niche Signals from the Choroid Plexus Regulate Adult Neural Stem Cells.
Sex, Specimen part
View SamplesTo identify early processes in carcinogenesis, we used an in vitro model, based on the initiating event in cervical cancer, human papillomavirus (HPV) transformation of keratinocytes. We compared gene expression in primary keratinocytes (K) and HPV16-transformed keratinocytes from early (E) and late (L) passages, and from benzo[a]pyrene treated L cells (BP). The transformed cells exhibit similar transcriptional changes to clinical cervical carcinoma. We revealed a contraction in expression of the apoptotic network during HF1 cell transformation, which affected the ability of L and BP cells to execute apoptosis, but did not lead to resistance to apoptotic stimuli. The contraction in the apoptotic machinery during the process of transformation was accompanied by a switch from apoptosis to necrosis in response to CDDP. The shrinkage of the pro- and anti-apoptotic networks appears to be part of a general contraction in the number of genes transcribed in L and BP cells. We also identified a large group of genes with induced expression, which are involved in cell metabolism and cell cycle, suggesting increased investment of the transformed cell in cellular proliferation. We hypothesize that the decrease in expression of many diverse pathways, including the pro- and anti-apoptotic networks, cuts the energy requirements for cell maintenance, allowing energy to be diverted towards rapid cell proliferation. This study supports the hypothesis that the process of cancer transformation may be accompanied by a shift from apoptosis to necrosis.
Shift from apoptotic to necrotic cell death during human papillomavirus-induced transformation of keratinocytes.
Specimen part, Cell line
View SamplesMicroglia depletion significantly lowered spine density in young (developing) but not mature adult-born-granule-cells (abGCs) in the olfactory bulb. PLX5622 significantly reduces microglia related gene transcripts. Overall design: We tested mouse olfactory bulb transcription in WT mice versus mice treated with a PLX5622 diet (inducing a near-complete microglia depletion).
The role of microglia and their CX3CR1 signaling in adult neurogenesis in the olfactory bulb.
Specimen part, Cell line, Subject
View SamplesMouse models of hepatocellular carcinoma (HCC) simulate specific subgroups of human HCC. We investigated hepatocarcinogenesis in Mdr2-KO mice, a model of inflammation-associated HCC, using gene expression profiling and immunohistochemical analyses. Gene expression profiling demonstrated that although Mdr2-KO mice differ from other published murine HCC models, they share several important deregulated pathways and many coordinately differentially expressed genes with human HCC datasets. Analysis of genome positions of differentially expressed genes in liver tumors revealed a prolonged region of down-regulated genes on murine chromosome 8 in three of the six analyzed tumor samples. This region is syntenic to human chromosomal regions that are frequently deleted in human HCC and harbor multiple tumor suppressor genes. Real-time RT-PCR analysis of 16 tumor samples confirmed down-regulation of several tumor suppressors in most tumors. We demonstrate that in the aged Mdr2-KO mice, cyclin D1 nuclear level is increased in dysplastic hepatocytes that do not form nodules; however, it is decreased in dysplastic nodules and in liver tumors. We found that this decrease is mostly at the protein, rather than the mRNA level. These findings raise the question on the role of cyclin D1 at early stages of hepatocarcinogenesis in the Mdr2-KO HCC model. Furthermore, we show that most liver tumors in Mdr2-KO mice were characterized by the absence of b-catenin activation. In conclusion, the Mdr2-KO mouse may serve as a model for b-catenin-negative subgroup of human HCCs characterized by low nuclear cyclin D1 levels in tumor cells and by down-regulation of multiple tumor suppressor genes.
Molecular mechanisms of liver carcinogenesis in the mdr2-knockout mice.
Age
View SamplesWe aimed to determine whether overexpression of endoderm-specific miRNA may affect hESC differentiation. To this end, we analyzed the effect of lentiviral-based overexpression of liver-specific miR-122 on hESC differentiation, using genomewide gene microarrays. Stable overexpression of endoderm-specific miR-122 in hESC resulted in increased expression of a few endodermal markers in spontaneously-differentiating hESC, but had no clear effect on directing differentiation towards an endodermal fate; rather, it delayed the general differentiation of hESC.
MicroRNA expression patterns and function in endodermal differentiation of human embryonic stem cells.
Cell line
View SamplesHepatocellular carcinoma (HCC) is the fifth most-common cancer worldwide causing nearly 600,000 deaths esch year. Approximately 80% of HCC develops on the background of cirrhosis.It is necessary to identify novel genes involved in HCC to implement new diagnostic and treatment options. However, the molecular pathogenesis of HCC largely remains unsolved. Only a few genetic alterations, namely those affecting p53, -catenin and p16INK4a have been implicated at moderate frequencies of these cancers. Early detection of HCC with appropriate treatment can decrease tumor-related deaths
Genome-wide transcriptional reorganization associated with senescence-to-immortality switch during human hepatocellular carcinogenesis.
Specimen part
View SamplesCellular senescence is a tumor suppressor mechanism, and immortalization facilitates neoplastic transformation. Both mechanisms may be highly relevant to hepatocellular carcinoma (HCC) development and its molecular heterogeneity. Cellular senescence appears to play a major role in liver diseases. Chronic liver diseases are associated with progressive telomere shortening leading senescence that is observed highly in cirrhosis, but also in some HCC. We previously described the generation of immortal and senescence-programmed clones from HCC-derived Huh7 cell line.
Genome-wide transcriptional reorganization associated with senescence-to-immortality switch during human hepatocellular carcinogenesis.
Sex, Specimen part
View SamplesWe studied the molecular mechanisms of hepatocellular carcinoma (HCC) initiation and promotion using the Mdr2-knockout (Mdr2-KO) mice at pre-cancerous stages of liver disease. These mice lack the liver-specific P-glycoprotein responsible for phosphatidylcholine transport across the canalicular membrane. Portal inflammation ensues at an early age followed by the development of HCC between the ages of 12 and 15 months. Liver tissue samples of Mdr2-KO and control Mdr2-heterozygotes mice aged 3 and 12 months, were subjected to histological, biochemical and gene expression profiling analysis using Affymetrix Mouse Genome Array.
Multiple adaptive mechanisms to chronic liver disease revealed at early stages of liver carcinogenesis in the Mdr2-knockout mice.
Age
View SamplesLangerhans cells (LCs) populate the mucosal epithelium, a major entry portal for pathogens, yet their ontogeny remains unclear. In contrast to skin LCs originating from self-renewing radioresistant embryonic precursors, we found that oral mucosal LCs derive from circulating radiosensitive precursors. Mucosal LCs can be segregated into CD103+CD11blow (CD103+LCs) and CD11b+CD103- (CD11b+LCs) subsets. We further demonstrated that similar to non-lymphoid dendritic cells (DCs), CD103+LCs originate from pre-DCs, whereas CD11b+LCs differentiate from both pre-DCs and monocytic precursors. Despite this ontogenetic discrepancy between skin and mucosal LCs, transcriptomic signature and immunological function of oral LCs highly resemble those of skin LCs but not DCs. These findings, along with their epithelial position, morphology and expression of LC-associated phenotype strongly suggest that oral mucosal LCs are genuine LCs. Collectively, in a tissue-dependent manner, murine LCs differentiate from at least three distinct precursors (embryonic, pre-DCs and monocytic) in steady state Overall design: The following cells were isolated from mice (2-4 replicates): Lung DCs, mucosal CD103+ LC, mucosal CD11b+ LC, Skin LC. Transcriptome analysis was performed.
Distinct Murine Mucosal Langerhans Cell Subsets Develop from Pre-dendritic Cells and Monocytes.
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View Samples