Project description:Purpose: to determine whether chronic low dose dioxin exposure in adult male and female mice impacts susceptibility to metabolic disease and islet dysfunction.
Project description:To explore the underlying mechanism for the regulatory role of SIRT3 in pancreatic islets under standard and high fat diet feeding, we conducted RNA sequencing on the isolated islets from standard diet and high fat diet-fed wild type and pancreatic beta cell selective Sirt3 knockout mice (four groups in total). Three biological replicates were performed for each group.
Project description:We report the application of next-generation sequencing technology for high-throughput profiling of H3K27ac and transcriptome analysis in pancreatic islets derived from C57Bl/6 mice fed a high-fat diet. We find genomic regions showing change in acetylation of histone H3K27 in response to long-term HFD feeding, which was significantly associated with differential gene expression. Furthermore, increased H3K27ac showed a distinctive genomic distribution surrounding proximal-promoter regions. This study provides a framework for the application of comprehensive chromatin profiling towards characterization of diverse mammalian cells under various environments.
Project description:To understand how gonadal adpose tissue is altered via maternal HFD feeding, we fed dams a 60% HFD only during weaning. These data are from the offspring, both control and HFD fed male mice
Project description:We report the application of next-generation sequencing technology for high-throughput profiling of H3K27ac and transcriptome analysis in pancreatic islets derived from C57Bl/6 mice fed a high-fat diet. We find genomic regions showing change in acetylation of histone H3K27 in response to long-term (26 weeks) HFD feeding, which was significantly associated with differential gene expression. Furthermore, increased H3K27ac showed a distinctive genomic distribution surrounding proximal-promoter regions. This study provides a framework for the application of comprehensive chromatin profiling towards characterization of diverse mammalian cells under various environments.
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 Ambion miRNA array platform as well as quantitative RT-PCR to measure miRNA levels in dioxin-sensitive Long-Evans (Turku/AB; L-E) rats vs. dioxin-resistant Han/Wistar(Kuopio; H/W) rats. Treatment with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in vivo caused no significant changes in miRNA levels in rat livers. AHR genotype had no effect on hepatic miRNA levels in response to TCDD – no miRNAs differed in expression between between L-E rats (that have wildtype AHR) compared to H/W rats (whose AHR has a large deletion in the transactivation domain). It is unlikely that mRNA downregulation by dioxins is mediated by miRNAs, nor are miRNAs likely to play a significant role in dioxin toxicity in adult rodent liver. 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, genetic modification, comparative genome hybridization
Project description:To identify novel neurocircuits activated upon short-term HFD feeding, we employed phosphoribotrap-profiling, which allows for the unbiased identification of alterations in neuronal activation via immunoprecipitation of phosphorylated S6 ribosomal protein-tagged ribosomes from hypothalamic extracts of mice exposed to either 3 days of normal chow diet or HFD-feeding. We have analyzed mRNA selectively expressed in hypothalamic cells activated by a either normal chow diet (NCD)-feeding for 3 days or high fat diet (HFD)-feeding for 3 days. 10-week-old male C57/BL6N mice were put either on a normal chow diet or a high fat diet for 3 days. Afterwards, mice were sacrificed by cervical dislocation. The hypothalamus was rapidly dissected using a stainless steel brain matrix and immediately frozen in liquid nitrogen. Hypothalamic tissues were pooled (8 per IP).
Project description:Dioxin is one of the most common historic industrial contaminants with several major industry and government accidents having exposed large numbers of the worldwide population over the past century. Previous rat studies have demonstrated the ability of dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)) exposure to promote the epigenetic transgenerational inheritance of disease susceptibility in subsequent generations. The types of disease observed include testis, ovary, kidney, prostate and obesity pathologies. The current study was designed to use an epigenome-wide association study (EWAS) to identify potential sperm DNA methylation biomarkers for specific transgenerational diseases. The transgenerational F3 generation dioxin lineage male rats with and without a specific disease were compared to identify differential DNA methylation regions (DMRs). The genomic features of the DMRs are characterized. Observations demonstrate that disease specific epimutation DMRs exist for the transgenerational dioxin lineage rats that can potentially be used as epigenetic biomarkers for testis, ovary, kidney, prostate and obesity diseases. These disease specific DMRs were associated with genes that have previously been shown to be linked with these diseases. This EWAS for transgenerational disease identified epigenetic biomarkers and provides the proof of concept of the potential to develop similar biomarkers for humans to diagnose disease susceptibilities and facilitate preventative medicine.
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 Ambion miRNA array platform as well as quantitative RT-PCR to measure miRNA levels in dioxin-sensitive Long-Evans (Turku/AB; L-E) rats vs. dioxin-resistant Han/Wistar(Kuopio; H/W) rats. Treatment with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in vivo caused no significant changes in miRNA levels in rat livers. AHR genotype had no effect on hepatic miRNA levels in response to TCDD – no miRNAs differed in expression between between L-E rats (that have wildtype AHR) compared to H/W rats (whose AHR has a large deletion in the transactivation domain). It is unlikely that mRNA downregulation by dioxins is mediated by miRNAs, nor are miRNAs likely to play a significant role in dioxin toxicity in adult rodent liver. 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, genetic modification, comparative genome hybridization In the dioxin-sensitive L-E rats we compared miRNA expression levels 19 h post-TCDD treatment vs. corn oil vehicle treatment. In the dioxin-resistant H/W rats we compared miRNA levels 19 h post-TCDD treatment vs.corn oil vehicle treatment.
Project description:The effect of high fat diet feeding on adipose tissue gene transcription regulation was investigated in C57Bl/6J mice using Affymetrix gene expression arrays. Expression profiling was determined in 5 months old male mice showing heterogeneous metabolic, hormonal and behavioral adaptation to high fat diet (40% fat) feeding for 15 weeks. Control mice were fed a standard carbohydrate chow. Six animals per group were used.