RNA-Seq of pancreatic islets derived from mice fed a long-term high-fat diet against chow-fed controls
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ABSTRACT: 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: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:Intensive oxidative stress occurs during high-fat-diet-induced hepatic fat deposition, suggesting a critical role for redox signaling in liver metabolism. Intriguingly, lines of evidence show that fasting could also result in redox profile changes, largely through reduced oxidant and/or increased anti-oxidant levels. However, a comprehensive landscape of redox-modified hepatic substrates is lacking, thus hindering our understanding of liver metabolic homeostasis. In this study, we employed a proteomic approach which combines iodoTMT and nanoLC-MS/MS to quantitatively probe the effects of high-fat-feeding and fasting on in vivo redox-based cysteine modifications. Collectively, we identified 1258 redox cysteine sites in 603 proteins and quantified 846 sites in 403 proteins.
Project description:One of the key functions of the mammalian liver is lipid metabolism. During fasting, lipid storage in the liver increases in order to reserve and provide energy for cellular functions. Upon re-feeding, this reserve of lipids is rapidly depleted; this change is visible, as the organelles responsible for lipid storage – lipid droplets (LDs) – drastically decrease in size following re-feeding. Little is known regarding LD proteome, or how it changes during the fasting/re-feeding transition. Our study investigated the hepatic LD proteome and how it changes between fasting and re-feeding conditions. For this purpose, LDs were isolated from 4 month-old C57BL/6 mice after a 24 hour fasting period, or a 24 hour fasting period followed by 6 hours of re-feeding. Proteins isolated from these LDs were subject to SDS-PAGE followed by in-gel trypsinization and LC-MS/MS. We identified a combined total of 941 proteins on hepatic LDs, of which 817 had quantifiable extracted ion chromatograms in at least 2 samples (n=6 total) and were not deemed contaminants. 777 of the 817 proteins were observed in both energetic states, with 33 being uniquely observed in fasted LDs, and 7 being uniquely observed in re-fed LDs.
Project description:Acquisition of the intestinal microbiota begins at birth, and a stable microbial community develops from a succession of key organisms. Disruption of the microbiota during maturation by low-dose antibiotic exposure can alter host metabolism and adiposity. We now show that low-dose penicillin (LDP), delivered from birth, induces metabolic alterations and affects ileal expression of genes involved in immunity. LDP that is limited to early life transiently perturbs the microbiota, which is sufficient to induce sustained effects on body composition, indicating that microbiota interactions in infancy may be critical determinants of long-term host metabolic effects. In addition, LDP enhances the effect of high-fat diet induced obesity. The growth promotion phenotype is transferrable to germ-free hosts by LDP-selected microbiota, showing that the altered microbiota, not antibiotics per se, play a causal role. These studies characterize important variables in early-life microbe-host metabolic interaction and identify several taxa consistently linked with metabolic alterations. Male and female mice were exposed to low-dose penicillin from birth. In a second experiment, microbiota from female control and LDP mice was transferred to 3-week old female germ-free mice. Livers were collected at 8 weeks of age, RNA was extracted, and transcriptional differences were measured by RNAseq.
Project description:The source of most errors in RNA sequencing (RNA-seq) read alignment is in the repetitive structure of the genome and not with the alignment algorithm. Genetic variation away from the reference sequence exacerbates this problem causing reads to be assigned to the wrong location. We developed a method, implemented as the software package Seqnature, to construct the imputed genomes of individuals (individualized genomes) of experimental model organisms including inbred mouse strains and genetically unique outbred animals. Alignment to individualized genomes increases read mapping accuracy and improves transcript abundance estimates. In an application to expression QTL mapping, this approach corrected erroneous linkages and unmasked thousands of hidden associations. Individualized genomes accounting for genetic variation will be useful for human short-read sequencing and other sequencing applications including ChIP-seq. Illumina 100bp single-end liver RNA-seq from 277 male and female Diversity Outbred 26-week old mice raised on standard chow or high fat diet. In addition, Illumina 100bp single-end liver RNA-seq from 128 male 26-week old male mice (20 weeks for NZO strain) from each of the DO founder strains raised on standard chow or high fat diet (8 males per strain by diet group). Each sample was sequenced in 2-4x technical replicates across multiple flowcells. Samples were randomly assigned lanes and multiplexed at 12-24x.
Project description:To model the potential diabetogenic effects of higher level of HSD11B1 in b-cells of the pancreas in vivo, we created a transgenic model overexpressing HSD11B1 under the mouse insulin I promoter (MIP-HSD1) in diabetes-prone C57Bl/KsJ mice. KsJ wild type and MIP-HSD1 heterozygous mice have been high fat fed for 12 weeks. Pancreata have been perfused with collagenase and islets isolated by hand picking. Isolated islets (around 500) coming from at least 3 mice (around 200/mice) have been directly lysed in Trizol. Total RNA have been extracted by Trizol plus RNA Purification Kit (invitrogen). Four biological replicates per group: Wild type KsJ mice on High Fat diet (KsJ1, KsJ2, KsJ3, KsJ4) and MIP-HSD1 transgenic mice on High Fat diet (MIP1, MIP2, MIP3, MIP4) were used to prepare RNA for microarray analysis.
Project description:Younger age and obesity increase the incidence and rates of metastasis of triple-negative breast cancer (TNBC), an aggressive subtype of breast cancer. The tissue microenvironment, specifically the extracellular matrix (ECM), is known to promote tumor invasion and metastasis. We sought to characterize the effect of both age and obesity on the ECM of mammary fat pads. We used a diet-induced obesity (DIO) model where 10-week-old female mice were fed a high-fat diet (HFD) for 16 weeks or a control chow diet (CD) where time points were every 4 weeks to monitor age and obesity HFD progression. We isolated the mammary fat pads to characterize the ECM at each time point. Utilizing proteomics, we found that the early stages of obesity were sufficient to induce distinct differences in the ECM composition of mammary fat pads that promote TNBC cell invasion. ECM proteins previously implicated in driving TNBC invasion Collagen IV and Collagen VI, were enriched with weight gain. Together these data implicate ECM changes in the primary tumor microenvironment as mechanisms by which age and obesity contribute to breast cancer progression.
Project description:Xbp1 is an important regulator of unfolded protein response and lipid metabolism. Its dyregulation has been associcated in human NASH. Feeding a high fat diet with fructose/sucrose to mice causes progressive, fibrosing steatohepatitis. This study is to use RNA-Seq to identify differentially expressed genes in hepatic Xbp1 deficient mice livers fed with a high fat diet compared to controls. Hepatic Xbp1 deficient mice or flox controls were fed either regular chow or a high fat diet (n=4). Samples from each cohort were pooled into two replicates.
Project description:Diet-induced obesity is reported to induce a phenotypic switch in adipose tissue macrophages from an antiinflammatory M2 state to a proinflammatory M1 state. Telmisartan, an angiotensin II type 1 receptor antagonist and a peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonist, reportedly has beneficial effects on insulin sensitivity. We studied the effects of telmisartan on the adipose tissue macrophage phenotype in high fat-fed mice. Telmisartan was administered for 5 weeks to high fat-fed C57BL/6 mice. Insulin sensitivity, macrophage infiltration, and the gene expressions of M1 and M2 markers in epididymal fat tissues were examined. Insulin- or a glucose-tolerance test showed that telmisartan treatment improved insulin resistance, decreasing the body weight gain, visceral fat weight and adipocyte size without affecting the amount of food intake. Telmisartan treatment reduced the number of CD11c-positive cells and crown-like structures. Telmisartan reduced the mRNA expressions of M1 macrophage markers, such as TNF-alpha and IL-6, and increased the expression of M2 markers, such as IL-10 and Mgl2. The reduction of M1 macrophage markers, as well as the increased gene expression of M2 markers especially IL-10, is a possible mechanism for the improvement of insulin sensitivity by telmisartan. Six-week-old male C57BL/6J mice were purchased from CLEA Japan. The mice were fed a chow that contained 10% of its calories from fat (control) or a high-fat diet (HFD) that contained 30% of its calories from fat for 24 weeks. The high fat-fed mice were randomized to 3 groups. Either telmisartan (~3 mg/kg/day) in drinking water (HFD+Tel), candesartan (~3 mg/kg/day) in drinking water (HFD+Can), or a HFD without any drugs (HFD) was administered for the next 5 weeks. Two mice were treated per group. Epididymal adipose tissues were rapidly removed from each mouse. Gene expression in epididymal fat tissue was analyzed using a GeneChip® system with the Mouse Genome 430 2.0 Array, which was spotted with 45,101 probe sets (Affymetrix, Santa Clara, CA, USA). Sample preparation for the array hybridization was performed according to the manufacturer’s instructions. In short, 5 μg of total RNA was used to synthesize double-stranded cDNA using the GeneChip® Expression 3′-Amplification Reagents One-Cycle cDNA Synthesis Kit (Affymetrix). Biotin-labeled cRNA was then synthesized from the cDNA using GeneChip® Expression 3′-Amplification Reagents for IVT Labeling (Affymetrix). After fragmentation, the biotinylated cRNA was hybridized to arrays at 45 °C for 16 h. The arrays were washed, stained with streptavidin-phycoerythrin, and scanned using a probe array scanner. The scanned chip was analyzed using the GeneChip Analysis Suite software (Affymetrix). Hybridization intensity data were converted into a presence/absence call for each gene, and changes in gene expression between experiments were detected by a comparison analysis. Data was shown as the fold change relative to the expression level of normal chow-fed mice.
Project description:For comparative epigenomic analysis of brown fat and white fat in mice, H3K27ac and PolII ChIP-seq were performed in each depot. H3K27ac histone modification and PolII transcription profiles in mouse brown and white adipose tissues