ABSTRACT: Integrative genomic analysis of CREB defines a critical role for transcription factor networks in mediating the fed/fasted switch in liver [array]
Project description:Integrative genomic analysis of CREB defines a critical role for transcription factor networks in mediating the fed/fasted switch in liver
Project description:Integrative genomic analysis of CREB defines a critical role for transcription factor networks in mediating the fed/fasted switch in liver [ChIP-seq]
Project description:Metabolic homeostasis in mammals critically depends on the regulation of fasting-induced genes by CREB in the liver. Previous genome-wide analysis has shown that only a small percentage of CREB target genes are induced in response to fasting-associated signaling pathways. The precise molecular mechanisms by which CREB specifically targets these genes in response to alternating hormonal cues remain to be elucidated. We performed chromatin immunoprecipitation coupled to high-throughput sequencing of CREB in livers from both fasted and re-fed mice. In order to quantitatively compare the extent of CREB-DNA interactions genome-wide between these two physiological conditions we developed a novel, robust analysis method, termed the ‘single sample independence’ (SSI) test that greatly reduced the number of false positive peaks. We found that CREB remains constitutively bound to its target genes in the liver regardless of the metabolic state. Integration of the CREB cistrome with expression microarrays of fasted and re-fed mouse livers and ChIP-seq data for additional transcription factors revealed that the gene expression switches between the fasted and fed states are associated with co-localization of additional transcription factors at CREB sites. Our results support a model in which CREB is constitutively bound to thousands of potential target genes and combinatorial interactions between DNA-binding factors are necessary to achieve the specific transcriptional response of the liver to fasting. Furthermore, our genome-wide analysis identifies thousands of novel CREB target genes in liver, including a previously unknown role for CREB in regulating ER stress genes in response to nutrient influx. Individual livers were collected from 24hr fasted and re-fed mice, with 4 biological replicates per condition. Extracted RNA was hybridized to Agilent two-color arrays, using randomly paired fasted/re-fed replicates.
Project description:Metabolic homeostasis in mammals critically depends on the regulation of fasting-induced genes by CREB in the liver. Previous genome-wide analysis has shown that only a small percentage of CREB target genes are induced in response to fasting-associated signaling pathways. The precise molecular mechanisms by which CREB specifically targets these genes in response to alternating hormonal cues remain to be elucidated. We performed chromatin immunoprecipitation coupled to high-throughput sequencing of CREB in livers from both fasted and re-fed mice. In order to quantitatively compare the extent of CREB-DNA interactions genome-wide between these two physiological conditions we developed a novel, robust analysis method, termed the M-bM-^@M-^Xsingle sample independenceM-bM-^@M-^Y (SSI) test that greatly reduced the number of false positive peaks. We found that CREB remains constitutively bound to its target genes in the liver regardless of the metabolic state. Integration of the CREB cistrome with expression microarrays of fasted and re-fed mouse livers and ChIP-seq data for additional transcription factors revealed that the gene expression switches between the fasted and fed states are associated with co-localization of additional transcription factors at CREB sites. Our results support a model in which CREB is constitutively bound to thousands of potential target genes and combinatorial interactions between DNA-binding factors are necessary to achieve the specific transcriptional response of the liver to fasting. Furthermore, our genome-wide analysis identifies thousands of novel CREB target genes in liver, including a previously unknown role for CREB in regulating ER stress genes in response to nutrient influx. CREB ChIP-seq was performed on mouse liver from fasted and re-fed mice, using 5 separate biological replicates for each condition. GR and C/EBP(beta) ChIP-seq were performed as single replicates on ad-lib fed mice.
Project description:Metabolic homeostasis in mammals critically depends on the regulation of fasting-induced genes by CREB in the liver. Previous genome-wide analysis has shown that only a small percentage of CREB target genes are induced in response to fasting-associated signaling pathways. The precise molecular mechanisms by which CREB specifically targets these genes in response to alternating hormonal cues remain to be elucidated. We performed chromatin immunoprecipitation coupled to high-throughput sequencing of CREB in livers from both fasted and re-fed mice. In order to quantitatively compare the extent of CREB-DNA interactions genome-wide between these two physiological conditions we developed a novel, robust analysis method, termed the ‘single sample independence’ (SSI) test that greatly reduced the number of false positive peaks. We found that CREB remains constitutively bound to its target genes in the liver regardless of the metabolic state. Integration of the CREB cistrome with expression microarrays of fasted and re-fed mouse livers and ChIP-seq data for additional transcription factors revealed that the gene expression switches between the fasted and fed states are associated with co-localization of additional transcription factors at CREB sites. Our results support a model in which CREB is constitutively bound to thousands of potential target genes and combinatorial interactions between DNA-binding factors are necessary to achieve the specific transcriptional response of the liver to fasting. Furthermore, our genome-wide analysis identifies thousands of novel CREB target genes in liver, including a previously unknown role for CREB in regulating ER stress genes in response to nutrient influx.
Project description:Metabolic homeostasis in mammals critically depends on the regulation of fasting-induced genes by CREB in the liver. Previous genome-wide analysis has shown that only a small percentage of CREB target genes are induced in response to fasting-associated signaling pathways. The precise molecular mechanisms by which CREB specifically targets these genes in response to alternating hormonal cues remain to be elucidated. We performed chromatin immunoprecipitation coupled to high-throughput sequencing of CREB in livers from both fasted and re-fed mice. In order to quantitatively compare the extent of CREB-DNA interactions genome-wide between these two physiological conditions we developed a novel, robust analysis method, termed the ‘single sample independence’ (SSI) test that greatly reduced the number of false positive peaks. We found that CREB remains constitutively bound to its target genes in the liver regardless of the metabolic state. Integration of the CREB cistrome with expression microarrays of fasted and re-fed mouse livers and ChIP-seq data for additional transcription factors revealed that the gene expression switches between the fasted and fed states are associated with co-localization of additional transcription factors at CREB sites. Our results support a model in which CREB is constitutively bound to thousands of potential target genes and combinatorial interactions between DNA-binding factors are necessary to achieve the specific transcriptional response of the liver to fasting. Furthermore, our genome-wide analysis identifies thousands of novel CREB target genes in liver, including a previously unknown role for CREB in regulating ER stress genes in response to nutrient influx.
Project description:Spatial heterogeneity and plasticity of the mammalian liver is critical for systemic metabolic homeostasis in response to fluctuating nutritional status. Here, we generated a high-resolution transcriptomic landscape of the livers from mice that were either fed chow (fed), fasted for 18 h (fasted), or fasted for 18 h and then refed for 6 h (refed) using spatial transcriptomics (ST) and quantified changes in gene expression. This work provides a critical foundation for future mechanistic studies of liver metabolic heterogeneity and plasticity, and will help to understand the zonated pathology during liver disease progression.
Project description:Regulation of nutrient status during fasting and refeeding plays an important role in maintaining metabolic homeostasis in the liver. Thus, we investigated the impact of the physiological fed–fasted–refed cycle on hepatic gene expression in nutrient-sensitive mice. We performed transcriptomic analysis of liver samples in fed, fasted and refed groups of mice. Through mRNA-sequencing (RNA-Seq) and miRNA-Seq, we compared fasted and fed states (fasted versus fed cohort) as well as refed and fasted states (refed versus fasted cohort) to detect dynamic alterations of hepatic mRNA– miRNA expression during the fed–fasted–refed cycle
Project description:Regulation of nutrient status during fasting and refeeding plays an important role in maintaining metabolic homeostasis in the liver. Thus, we investigated the impact of the physiological fed–fasted–refed cycle on hepatic gene expression in nutrient-sensitive mice. We performed transcriptomic analysis of liver samples in fed, fasted and refed groups of mice. Through mRNA-sequencing (RNA-Seq) and miRNA-Seq, we compared fasted and fed states (fasted versus fed cohort) as well as refed and fasted states (refed versus fasted cohort) to detect dynamic alterations of hepatic mRNA– miRNA expression during the fed–fasted–refed cycle
Project description:102 postpubertal Holstein dairy heifers were randomly assigned to a fed or fasted treatment. Liver biopsies were performed to obtain tissue from which mRNA was extracted and used for microarray analysis. Transcriptional profiling revealed adaptive mechanisms in response to negative energy balance. Two condition experiment; fed and fasted. Common reference design employed; reference sample consisting of RNA derived from bovine liver, spleen and placental tissue. Biological replicates of 51 Fed (as control) and 51 Fasted (as treatment). One replicate per array. Dye swaps performed on 7 of the 51 fasted treatment group samples, and on 5 of the 51 fed treatment group samples.