Project description:Kidney miRNA expression was examined in F344 rats at 2, 5, 6, 8, 15, 21, 78, and 104 weeks of age in both sexes using Agilent miRNA microarrays. 311 miRNAs were found to be expressed in at least one age and sex. Filtering criteria of ?1.5 fold change and ANOVA (FDR <5%) revealed 174 differentially expressed miRNAs in the kidney; 173 and 34 miRNAs exhibiting age and sex effects, respectively. Principal component analysis revealed age effects predominated over sex effects, with 2 week miRNA expression being much different from other ages. No significant sexually dimorphic miRNA expression was observed from 5 to 8 weeks, while the most differential expression (13 miRNAs) was observed at 21 weeks. Potential target genes of these differentially expressed miRNAs were identified. Pathway analysis was used to investigate the possible roles of these target genes in age- and sex-specific differences. Untreated male and female F344 rats from 2, 5, 6, 8, 15, 21, 78, and 104 weeks of age (n=5) were sacrificed by CO2 asphyxiation, whole kidneys collected and homogenized, total RNA, including small RNA fraction, was used for miRNA expression arrays (Agilent).
Project description:The kidney is important for a number of physiological processes including blood filtering, blood pressure regulation and proper excretion of many drugs and xenobiotics. Age is a predisposing condition for susceptibility to chronic kidney disease and progression as well as acute kidney injury that may arise due to the adverse effects of some drugs. Age-related differences in kidney biology, therefore, are a key concern in understanding drug safety and disease progression. We hypothesize that the underlying suite of genes expressed in the kidney at various life cycle stages will impact susceptibility to adverse drug reactions. Therefore, establishing changes in baseline expression data between these life stages is the first and necessary step in evaluating this hypothesis. Untreated male F344 rats from 2, 5, 6, 8, 15, 21, 78, and 104 weeks of age (n=5) were sacrificed by CO2 asphyxiation, whole kidneys collected and homogenized, total RNA used for whole genome expression arrays (Agilent).
Project description:The kidney functions in key physiological processes to filter blood and regulate blood pressure via key molecular transporters and ion channels. Sex-specific differences have been observed in renal disease incidence and progression as well as acute kidney injury in response to certain drugs. Although advances have been made in characterizing the molecular components involved in various kidney functions, the molecular mechanisms responsible for sex differences are not well understood. We hypothesized that the basal expression levels of genes involved in various kidney functions throughout the life cycle will influence sex-specific susceptibilities to adverse renal events. Untreated female F344 rats from 2, 5, 6, 8, 15, 21, 78, and 104 weeks of age (n=5) were sacrificed by CO2 asphyxiation, whole kidneys collected and homogenized, total RNA used for whole genome expression arrays (Agilent).
Project description:The rat has been used extensively as a model for evaluating chemical toxicities and for understanding drug mechanisms. However, its transcriptome across multiple organs, or developmental stages, has not yet been reported. Here we show, as part of the SEQC consortium efforts, a comprehensive rat transcriptomic BodyMap created by performing RNASeq on 320 samples from 11 organs of both sexes of juvenile, adolescent, adult and aged Fischer 344 rats. We catalogue the expression profiles of 40,064 genes, 65,167 transcripts, 31,909 alternatively spliced transcript variants and 2,367 non-coding genes/non-coding RNAs (ncRNAs) annotated in AceView. We find that organ-enriched, differentially expressed genes reflect the known organ-specific biological activities. A large number of transcripts show organ-specific, age-dependent or sex-specific differential expression patterns. We create a web-based, open-access rat BodyMap database of expression profiles with crosslinks to other widely used databases, anticipating that it will serve as a primary resource for biomedical research using the rat model. We constructed a comprehensive RNA-Seq data set for studying the dynamics of the rat transcriptome using 320 RNA samples isolated from 11 organs (adrenal gland, brain, heart, kidney, liver, lung, muscle, spleen, thymus, and testes or uterus) from both sexes of Fischer 344 rats across four developmental stages (2-, 6-, 21-, and 104-weeks-old). Four biological replicates were used for each of the 80 sample groups.
Project description:In addition to gaining knowledge on in vivo miRNA responses to formaldehyde, we set out to relate these miRNA responses to transcriptional profiles modified by formaldehyde. Rats were exposed by inhalation to either 0 or 2 ppm formaldehyde (6 hours/day) for 28 days. Genome-wide transcriptional profiles and associated signaling pathways were assessed within the nasal respiratory mucosa and circulating mononuclear white blood cells (WBC). Male Fischer rats received nose-only inhalation exposures of 2 ppm formaldehyde for 7 days or 28 days (6 hours/day). Control (unexposed) rats were placed in nose-only exposure tubes containing room air for the same duration. After the last exposure period, animals were euthanized. RNA were assessed from sampes collected from the nasal epithelium and circulating white blood cells. Genome-wide mRNA expression profiles were evaluated using microarrays.
Project description:Preclinical biomarkers useful for identification of idiosyncratic drugs have not been identified. It is hypothesized that patterns of transcript expression for the hepatotoxicants, including classical and idiosyncratic hepatotoxicants, are similar and the patterns differ from those of non-hepatotoxicants. This experiment is part of the biomarkers study, and focus on two clasical hepatotoxicants: Acetaminophen and Carbon tetrachloride. We have employed whole genome microarray expression profiling to identify liver gene expression changes induced by hepatotoxicants. For the same animal, urinary microRNA profiling were analyzed. APAP and CCl4 both significantly increased the urinary levels of 44 and 28 miRNAs, respectively. In addition, 10 of the increased miRNAs were in common between APAP and CCl4. Computational analysis was used to predict target genes of the 10 shared hepatotoxicant-induced miRNAs. From the same animals, liver gene expression profiling was performed using whole genome microarrays. Eight putative target genes were found to be significantly altered in the liver of APAP and CCl4 treated animals. Acetaminophen induced liver gene expression changes in rats (Six to seven week-old male Sprague-Dawley rats, provided by the US Food and Drug Administration National Center for Toxicological Research (NCTR) breeding colonies, were used for the study.) were measured at 6 hours, 24 hours, 3 days and 7 days after exposure to doses of 0, 100 and 1250 mg/kg. Carbon tetrachloride induced liver gene expression changes in rats were measured at 6 hours, 24 hours and 3 days after exposure to doses of 0, 50 and 2000 mg/kg. Each group has at least 4 animals, total of 96 samples.
Project description:ABSTRACT: The central nervous system is remarkably plastic in its ability to recover from trauma. We examined recovery from hexahydro-1,3,5-trinitrotriazine (RDX) induced seizures in rat through changes in transcriptional networks. Transcriptional networks from time series experiments provide a good basis for organizing and studying the dynamic behavior of biological processes. The goal of this work was to identify networks affected by chemical exposure and track changes in these networks as animals recover. We examined brain microarray data from rats exposed to 0, 1.2, 12, 24, and 47 mg RDX/kg body weight at different time points after exposure (24hr, 48hr, 7d, 14d, 28d and 90d). RESULTS A credible transcriptional network was constructed from the gene expression microarray data, which predicts the role of some key genes such as heat shock proteins, neuropeptide Y, thyrotropin-releasing hormones, growth factors, and ion channels in neurotransmission and neuroprotective mechanisms. Examination of the dynamic changes in expression within this network over time provided insight into CNS protective mechanisms from traumas. Single RDX Exposure with Various Time Points, Brain Tissue Investigation: Sprague-Dawley female rats were exposed to a single oral gavage of one of four concentrations of RDX or vehicle control with sampling periods of 24h, 48h, 7d, 14d, 28d, or 90d. Brain tissue was investigated for differential expression in response to RDX exposure and provide insight into CNS protective mechanisms associated with RDX exposure.
Project description:MicroRNAs (miRNAs) are critical regulators of gene expression, yet much remains unknown regarding miRNA changes resulting from environmental exposures and whether they influence pathway signaling across various tissues and time. To gain knowledge on these novel topics, we set out to investigate in vivo miRNA responses to inhaled formaldehyde, an important air pollutant known to disrupt miRNA expression profiles. Rats were exposed by inhalation to either 0 or 2 ppm formaldehyde (6 hours/day) for 7 days, 28 days, or 28 days followed by a 7 day recovery. Genome-wide miRNA expression profiles and associated signaling pathways were assessed within the nasal respiratory mucosa, circulating mononuclear white blood cells (WBC), and bone marrow (BM). Male Fischer rats received nose-only inhalation exposures of 2 ppm formaldehyde. Three exposure durations were investigated: (1) 2 ppm formaldehyde exposure, 6 hours/day, for 7 days (7-day group), (2) 2 ppm formaldehyde exposure, 6 hours/day, for 28 days (28-day group), and (3) 2 ppm formaldehyde exposure, 6 hours/day, for 28 days, with a 7 day recovery period following the last exposure (28-day plus recovery group). Control (unexposed) rats were placed in nose-only exposure tubes containing room air for the same duration. After the last exposure period (or the last recovery period for the 28-day plus recovery group), animals were euthanized. RNA were assessed from sampes collected from the nasal epithelium, circulating white blood cells, and bone marrow cells. Genome-wide miRNA expression profiles were evaluated using microarrays.