ABSTRACT: To further development of insight into the mechanism of toxicity, it is important to employ whole genome microarray expression profiling to identify and characterize miRNAs profiles as a discovery platform relevant for toxicologic mechanisms of hexanal. miRNAs have prominent role in cell cycle control, apoptosis, cancer development and proliferation-related processes. However, few reports have described the effect of hexanal on miRNA expression profiles using animal model. In this respect, we studied the expression profiles of miRNAs in hexanal-exposed in rats by miRNA microarray analysis. To evaluate the miRNA expression in lung tissue of rats after exposure of hexanal, Fischer-344 rats were inhaled to three concentrations (600, 1000, 1500 mg/m3) for 5 weeks. miRNA expression analysis was conducted using Rat miRNA 8 x 15K microarray v19.0 (Agilent Technologies, USA).
Project description:To further development of insight into the mechanism of toxicity, it is important to employ whole genome microarray expression profiling as a discovery platform to ientify genes with the potential to distinguish hexanal exposure across an exposure range relevant for toxicologic mechanisms. However, few reports have described the effect of hexanal on gene expression profiles using animal model. In this respect, we studied the expression profiles of mRNAs in hexanal-exposed in rats by microarray analysis. To evaluate the gene expression in lung tissue of rats after exposure of hexanal, Fischer-344 rats were inhaled to three concentrations (600, 1000, 1500 mg/m3) for 5 weeks. mRNA expression analysis was conducted using Rat GE(v3) 4X44K microarray (Agilent Technologies, USA).
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:With the population of older and overweight individuals on the rise in the Western world, there is an ever greater need to slow the aging processes and reduce the burden of age-associated chronic disease that would significantly improve the quality of human life and reduce economic costs. Caloric restriction (CR), is the most robust and reproducible intervention known to delay aging and to improve healthspan and lifespan across species (1); however, whether this intervention can extend lifespan in humans is still unknown. Here we report that rats and humans exhibit similar responses to long-term CR at both the physiological and molecular levels. CR induced broad phenotypic similarities in both species such as reduced body weight, reduced fat mass and increased the ratio of muscle to fat. Likewise, CR evoked similar species-independent responses in the transcriptional profiles of skeletal muscle. This common signature consisted of three key pathways typically associated with improved health and survival: IGF-1/insulin signaling, mitochondrial biogenesis and inflammation. To our knowledge, these are the first results to demonstrate that long-term CR induces a similar transcriptional profile in two very divergent species, suggesting that such similarities may also translate to lifespan-extending effects in humans as is known to occur in rodents. These findings provide insight into the shared molecular mechanisms elicited by CR and highlight promising pathways for therapeutic targets to combat age-related diseases and promote longevity in humans. Male Fisher 344 rats (n=54) were randomly assigned to two groups at 2 months of age. One group was kept ad libitum (AL) fed throughout their lifespan while the calorie restriction (CR) group was progressively brought down to a 40% CR. All animals were fed a NIH-31 standard chow (Harlan Teklad, Indianapolis, IN, USA). Rats were singly housed in an environmentally controlled vivarium with unlimited access to water and a controlled photoperiod (12 hr. light;12 hr. dark). Body weights and food intake were recorded biweekly. All rats were maintained between 68-72M-BM-0F according to animal protocols and NIH guidelines. Total RNA was extracted from the vastus lateralis skeletal muscle using Trizol Reagent (Invitrogen, Carlsbad, CA) following the manufacturerM-bM-^@M-^Ys instructions, n=5 from each group. Total RNA samples were biotin labeled and hybridized to RatRef-12 v1 Gene Expression beadchips (Illumina, San Diego, CA) following Illumina protocols. Arrays were washed and scanned using an Illumina BeadArray 500GX reader. Microarray florescent signals were extracted using the Illumina GenomeStudio Gene Expression software(v1.6.0) and any spots at or below the background were filtered using an Illumina detection p-value of 0.02 and above. The natural log of all remaining scores were used to find the avg and std of each array and the z-score normalization was calculated . Correlation analysis, sample clustering analysis and principal component analysis include all of probes are performed to identify/exclude any possible outliners. The resulting dataset was next analyzed with DIANE 6.0, a spreadsheet based microarray analysis program. Gene set enrichment analysis use gene expression values or gene expression change values for all of the genes in the microarray. Parametric analysis of gene set enrichment (PAGE) was used [pubmed 20682848] for gene set analysis. Gene Sets include the MSIG database [Link], Gene Ontology Database [Link], GAD human disease and mouse phenotype gene sets [pubmed: 20092628] were used to explore functional level changes.
Project description:Dioxin-like chemicals are well-known for their ability to upregulate expression of numerous genes via the AH receptor (AHR). However, recent transcriptomic analyses in several laboratories indicate that dioxin-like chemicals or AHR genotype itself also can downregulate levels of mRNAs encoded by numerous genes. The mechanism responsible for such downregulation is unknown. We hypothesized that microRNAs (miRNAs), which have emerged as powerful negative regulators of mRNA levels in several systems, might be responsible for mRNA downregulation in dioxin/AHR pathways. We used the Exiqon miRNA array platform as well as quantitative RT-PCR to measure miRNA levels in dioxin-sensitive Long-Evans (Turku/AB; L-E) rats. Treatment with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for 96 hr in vivo caused few changes in miRNA levels in rat livers and those changes that were statistically significant were of modest magnitude. Feed-restricted-control L-E rats were included to ensure that changes in miRNA levels were due to TCDD-treatment per se and not the result of the decreased feed intake which occurs in dioxin-sensitive strains within 96 h after TCDD exposure. Manuscript Submitted: Moffat ID, Boutros PC, Celius T, Pohjanvirta R & Okey AB. Micro-RNAs in rodent liver are refractory to dioxin treatment. Toxicological Sciences May, 2007. Keywords: miRNA expression, response to xenobiotics, feed restriction response A loop design used to profile miRNA levels from dioxin-sensitive L-E AHRWT/WT vehicle-control rats (LC96), those exposed to TCDD for 96 h (LT96), and feed-restricted (LF96) rats.
Project description:miRNAs are not well known their expression and function in tooth development. To identify the miRNAs expression during tooth development, tooth germs were dissected from the initiation bud, cap and bell stages. miRNA-chip expression analysis was performed with RNAs of the molar tooth germs from embryos of pregnant mice at emrbryonic day 11, 12, 14, and 16, using Agilent's miRNA microarray.
Project description:Microarray analysis of parity induced gene expression changes in the mammary glands of four strains of rats to identify a common gene signature associated with protection against methylnitrosourea induced mammary tumorigenesis.
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.
Project description:To identify the key microRNAs (miRNAs) of hMSCs required for fate determination, miRNA profiling was performed with hMSCs from three different sources including adipose-derived stem cells (ADSCs), bone-marrow-derived stem cells (BMSCs), and umbilical cord-derived stem cells (UCSCs) versus fibroblasts, a more differentiated mesenchymal cell types. We compared the expression profiles of two different donors per hMSCs to that of fibroblasts. All hMSCs were used for profiling at passage 3-6.
Project description:We aimed to investigate the miRNA expression patterns in Y79 cells, which are from a representative retinoblastoma cell line. We prepared 3 independent sets of cell lysates of Y79 cells in normal culture conditions. Total RNA was prepared from each set of cell lysates using Trizol reagent.