Project description:The project had 2 goals: 1) To evaluate the transcriptional response of 3 prototypical toxicants (Clofibrate, VPA, and DEHP) on rat lever. 2) To evaluate the impact pooling samples has on data analysis. Keywords = Clofibrate Keywords = Diethylhexyl phthalate Keywords = Phthalic acid bis(2-ethylhexyl ester) Keywords = Sodium Valproate Keywords = Valproic Acid Keywords = VPA Keywords = vehicle Keywords: other
Project description:The project had 2 goals:; 1) To evaluate the transcriptional response of 3 prototypical toxicants (Clofibrate, VPA, and DEHP) on rat lever. 2) To evaluate the impact pooling samples has on data analysis. Experiment Overall Design: Male SD rats were given a single dose of one of 3 prototypical toxicants or dosed with vehicle. The toxicants used were: Experiment Overall Design: 1000mg/kg Clofibrate (in 0.9% saline) Experiment Overall Design: 2000mg/kg Sodium Valproate (in distilled water) Experiment Overall Design: 20g/kg DEHP (in distilled water) Experiment Overall Design: Animals were sacrificed at 4, 24, 48, or 168hrs post-dosing (only 48 and 168hrs for vehicle-treated animals) Experiment Overall Design: One of the goals of this study was to assess the impact pooling RNA samples has on the array data. For each treatment and vehicle group there are 3-5 individual samples, as well as 1 pooled sample. Experiment Overall Design: 10ug of total RNA were hybridized to Affymetrix RG_U34A arrays according to the manufacturer's protocol. Signal intensities were generated using MAS5, with global scaling set to 1500.
Project description:A series of two color gene expression profiles obtained using Agilent 44K expression microarrays was used to examine sex-dependent and growth hormone-dependent differences in gene expression in rat liver. This series is comprised of pools of RNA prepared from untreated male and female rat liver, hypophysectomized (‘Hypox’) male and female rat liver, and from livers of Hypox male rats treated with either a single injection of growth hormone and then killed 30, 60, or 90 min later, or from livers of Hypox male rats treated with two growth hormone injections spaced 3 or 4 hr apart and killed 30 min after the second injection. The pools were paired to generate the following 6 direct microarray comparisons: 1) untreated male liver vs. untreated female liver; 2) Hypox male liver vs. untreated male liver; 3) Hypox female liver vs. untreated female liver; 4) Hypox male liver vs. Hypox female liver; 5) Hypox male liver + 1 growth hormone injection vs. Hypox male liver; and 6) Hypox male liver + 2 growth hormone injections vs. Hypox male liver. A comparison of untreated male liver and untreated female liver liver gene expression profiles showed that of the genes that showed significant expression differences in at least one of the 6 data sets, 25% were sex-specific. Moreover, sex specificity was lost for 88% of the male-specific genes and 94% of the female-specific genes following hypophysectomy. 25-31% of the sex-specific genes whose expression is altered by hypophysectomy responded to short-term growth hormone treatment in hypox male liver. 18-19% of the sex-specific genes whose expression decreased following hypophysectomy were up-regulated after either one or two growth hormone injections. Finally, growth hormone suppressed 24-36% of the sex-specific genes whose expression was up-regulated following hypophysectomy, indicating that growth hormone acts via both positive and negative regulatory mechanisms to establish and maintain the sex specificity of liver gene expression. For full details, see V. Wauthier and D.J. Waxman, Molecular Endocrinology (2008)
Project description:In order to establish a rat embryonic stem cell transcriptome, mRNA from rESC cell line DAc8, the first male germline competent rat ESC line to be described and the first to be used to generate a knockout rat model was characterized using RNA sequencing (RNA-seq) analysis.
Project description:Living organisms are intricate systems with dynamic internal processes. Their RNA, protein, and metabolite levels fluctuate in response to variations in health and environmental conditions. Among these, RNA expression is particularly accessible for comprehensive analysis, thanks to the evolution of high throughput sequencing technologies in recent years. This progress has enabled researchers to identify unique RNA patterns associated with various diseases, as well as to develop predictive and prognostic biomarkers for therapy response. Such cross-sectional studies allow for the identification of differentially expressed genes (DEGs) between groups, but they have limitations. Specifically, they often fail to capture the temporal changes in gene expression following individual perturbations and may lead to significant false discoveries due to inherent noise in RNA sequencing sample preparation and data collection. To address these challenges, our study hypothesized that frequent, longitudinal RNA sequencing (RNAseq) analysis of blood samples could offer a more profound understanding of the temporal dynamics of gene expression in response to drug interventions, while also enhancing the accuracy of identifying genes influenced by these drugs. In this research, we conducted RNAseq on 829 blood samples collected from 84 Sprague-Dawley lab rats. Excluding the control group, each rat was administered one of four different compounds known for liver toxicity: tetracycline, isoniazid, valproate, and carbon tetrachloride. We developed specialized bioinformatics tools to pinpoint genes that exhibit temporal variation in response to these treatments.