We previously identified the mTOR pathway as critical to progenitor cell proliferation in a model of liver injury, we investigated the temporal activation of mTOR signaling in a rat model of hepatic carcinogenesis. The model employed chemical carcinogens and partial hepatectomy to induce progenitor marker-positive HCC. Rats were administered the mTOR inhibitor rapamycin for a three week period and liver harvested one month following cessation of rapamycin treatment. Short-term rapamycin treatment resulted in a significant reduction of focal lesion burden. Microarray analysis was performed to characterize the gene expression signature of persistent focal lesions in the rapamcyin and placebo treated animals. This analysis revealed a persistent effect of short-term mTORC1 inhibition on gene expression that resulted in a genetic signature reminiscent of normal liver.
Persistent effect of mTOR inhibition on preneoplastic foci progression and gene expression in a rat model of hepatocellular carcinoma.
Sex, Specimen part, TreatmentView Samples
Genomic, proteomic, and metabolomic technologies continue to receive increasing interest from environmental toxicologists. This interest is due to the great potential of these technologies to identify detailed modes of action and to provide assistance in the evaluation of a contaminant’s risk to aquatic organisms. Our experimental model is the zebrafish (Danio rerio) exposed to reference endocrine disrupting compounds in order to investigate compound-induced changes in gene transcript profiles. Adult, female zebrafish were exposed to 0, 15, 40, and 100 ng/L of 17 alpha-ethynylestradiol (EE2) and concentration and time-dependent changes in hepatic gene expression were examined using Affymetrix GeneChip® Zebrafish Genome Microarrays. At 24, 48, and 168 hours, fish were sacrificed and liver mRNA was extracted for gene expression analysis (24 and 168 hours only). In an effort to link gene expression changes to effects on higher levels of biological organization, body and ovary weights were measured and blood was collected for measurement of plasma steroid hormones (17 beta-estradiol (E2), testosterone (T)) and vitellogenin (VTG) using ELISA. EE2 exposure significantly affected GSI, E2, T, VTG and gene expression. We observed 1575 genes that were significantly affected (up- or down-regulated by at least 1.5-fold (p ? 0.001) in a concentration-dependent manner by EE2 exposure at either 24 or 168 hours. EE2 exposure altered transcription of genes involved in steroid hormone homeostasis, cholesterol homeostasis, retinoic acid metabolism, and cell growth and proliferation. Plasma VTG was significantly increased at 24, 48, and 168 hours (p<0.05) at 40 and 100 ng/L and at 15 ng/L at 168 hours. E2 and T were significantly reduced following EE2 exposure at 48 and 168 hours. GSI was decreased in a dose-dependent manner at 168 hours. In this study, we identified genes involved in a variety of biological functions that have the potential to be used as markers of exposure to estrogenic substances. Future work will evaluate the use of these genes in zebrafish exposed to weak estrogens to determine if these genes are indicative of exposure to estrogens with varying potencies.
Hepatic gene expression profiling using Genechips in zebrafish exposed to 17alpha-ethynylestradiol.
Sex, Specimen part, Compound, TimeView Samples
Liposarcoma is the most common soft tissue sarcoma, accounting for about 20% of cases. Liposarcoma is classified into 5 histologic subtypes that fall into 3 biological groups characterized by specific genetic alterations. To identify genes that contribute to liposarcomagenesis and to better predict outcome for patients with the disease, we undertook expression profiling of liposarcoma. U133A expression profiling was performed on 140 primary liposarcoma samples, which were randomly split into training set (n=95) and test set (n=45). A multi-gene predictor for distant recurrence-free survival (DRFS) was developed using the supervised principal component method. Expression levels of the 588 genes in the predictor were used to calculate a risk score for each patient. In validation of the predictor in the test set, patients with low risk score had a 3-year DRFS of 83% vs. 45% for high risk score patients (P=0.001). The hazard ratio for high vs. low score, adjusted for histologic subtype, was 4.42 (95% confidence interval 1.26-15.55; P=0.021). The concordance probability for risk score was 0.732. Genes related to adipogenesis, DNA replication, mitosis, and spindle assembly checkpoint control were all highly represented in the multi-gene predictor. Three genes from the predictor, TOP2A, PTK7, and CHEK1, were found to be overexpressed in liposarcoma samples of all five subtypes and in liposarcoma cell lines. Knockdown of these genes in liposarcoma cell lines reduced proliferation and invasiveness and increased apoptosis. Thus, genes identified from this predictor appear to have roles in liposarcomagenesis and have promise as therapeutic targets. In addition, the multi-gene predictor will improve risk stratification for individual patients with liposarcoma.
Expression profiling of liposarcoma yields a multigene predictor of patient outcome and identifies genes that contribute to liposarcomagenesis.
Specimen partView Samples
PTBA has been published to increase renal tubular cell proliferation, increased survival, and increased renal functional recovery in fish and various models of murine models of acute kidney injury. Immunohistological analyses suggested increased cell proliferation is accompanied by increased epithelial-to-mesenchymal transition in the RTECs. In order to elucidate pathways responsible for the increased repair response after compound treatment, larval zebrafish were given AKI and treated with PTBA analogue, UPHD25 or DMSO. Results suggests that epithelial-related genes were downregulated while mesenchymal-related genes were upregulated with injury and compound treatment. Results further validate our immunohistological finding that our compound increase post-AKI repair by increasing EMT in renal tubular cells. Overall design: At 3dpf, larval zebrafish are given acute kidney injury with gentamicin microinjection. 2 days post injury, larvae with AKI are selected and treated with 1uM of PTBA analogue, UPHD25 or vehicle control, 1% DMSO. The fish were treated with UPHD25 or DMSO for 24 hours. Then, pronephric kidneys were collected using DDT, collagenase I, and manual collection. Total 100 larvae were collected per sample, per replicate. Each treatment group was repeated with 3 biological replicates. RNA was collected and sequenced.
Enhancing regeneration after acute kidney injury by promoting cellular dedifferentiation in zebrafish.
Specimen part, Treatment, SubjectView Samples
Renal recovery following injury relies on cellular regeneration. In the mouse kidney following injury, injured epithelial cells undergoes de-differentiate, proliferate and re-differentiate into functional cells, following a a tightly controlled genetic programme where specific sets of genes are up-regulated.
Histone deacetylase inhibitor enhances recovery after AKI.
Specimen partView Samples
Neuronal function critically depends on coordinated subcellular distribution of mRNAs. Disturbed mRNA processing and axonal transport has been found in spinal muscular atrophy and could be causative for dysfunction and degeneration of motoneurons. Despite the advances made in characterizing the transport mechanisms of several axonal mRNAs, an unbiased approach to identify the axonal repertoire of mRNAs in healthy and degenerating motoneurons has been lacking. Here we used compartmentalized microfluidic chambers to investigate the somatodendritic and axonal mRNA content of cultured motoneurons by microarray analysis. In axons, transcripts related to protein synthesis and energy production were enriched relative to the somatodendritic compartment. Knockdown of Smn, the protein deficient in spinal muscular atrophy, produced a large number of transcript alterations in both compartments. Transcripts related to immune functions, including MHC class I genes, and with roles in RNA splicing were upregulated in the somatodendritic compartment. On the axonal side, transcripts associated with axon growth and synaptic activity were downregulated. These alterations provide evidence that subcellular localization of transcripts with axonal functions as well as regulation of specific transcripts with nonautonomous functions is disturbed in Smn-deficient motoneurons, most likely contributing to the pathophysiology of spinal muscular atrophy.
Subcellular transcriptome alterations in a cell culture model of spinal muscular atrophy point to widespread defects in axonal growth and presynaptic differentiation.
Specimen partView Samples
The transcriptomic changes induced in the human liver cell line HepG2 by 100M menadione, 200M TBH or 50M H2O2 after treatment for 0.5, 1, 2, 4, 6, 8 and 24h.
Time series analysis of oxidative stress response patterns in HepG2: a toxicogenomics approach.
Cell lineView Samples
Tumor cells utilize the so-called Warburg effect to allow for rapid proliferation with glucose as the main nutrient. We show here that, although PKCz is critical for that effect, its deficiency promotes the plasticity necessary for nutrient-stressed cancer cells to reprogram their metabolism to utilize glutamine through the serine biosynthetic pathway, empowering them to survive and proliferate in the absence of glucose. We show that PKCz deficiency enhances glutamine utilization and expression of two key enzymes of the pathway, PGHDGH and PSAT1, in cells cultured in the absence of glucose. The loss of PKCz in mice results in enhanced intestinal tumorigenesis and increased levels of these two metabolic enzymes, while patients with low levels of PKCz have a poor prognosis. Taken together, this suggests that PKCz is a critical metabolic tumor suppressor.
Control of nutrient stress-induced metabolic reprogramming by PKCζ in tumorigenesis.
Cell line, TreatmentView Samples
Purpose: Epidemiological and intervention studies have attempted to link the health effects of a diet rich in fruits and vegetables with the consumption of polyphenols and their impact in neurodegenerative diseases. Studies have shown that polyphenols can cross the intestinal barrier and reach concentrations in the bloodstream able to exert effects in vivo. However, the effective uptake of polyphenols in the brain is still regarded with some reservations. Here we describe a combination of approaches to examine the putative transport of blackberry-digested polyphenols (BDP) across the blood-brain barrier (BBB) and ultimate evaluation of their beneficial effects.
Blood-brain barrier transport and neuroprotective potential of blackberry-digested polyphenols: an in vitro study.
Sex, Specimen part, Cell line, RaceView Samples
Understanding the mechanisms that specify neuronal subtypes is important to unravel the complex mechanisms of neuronal circuit assembly. Here we have identified a novel role for the transcription factor AP2 in progenitor and neuronal subtype specification in the cerebral cortex. Conditional deletion of AP2 causes misspecification of basal progenitors starting at
AP2gamma regulates basal progenitor fate in a region- and layer-specific manner in the developing cortex.
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