Project description:In order to identify the RNAs bound by NONO complexes in different nutritional conditions, we carried out RNA immunoprecipitation followed by sequencing (RIP-seq) of NONO from mouse liver nuclei collected at three different times of the day. Samples were collected after fasting (ZT10), 2h after re-feeding (ZT14) and towards the end of the feeding period (ZT22). The co-immunoprecipitated RNA (along with input RNA and unspecific IgG bound RNA) was sequenced.
Project description:The liver circadian transcriptome results from the combined action of a circadian clock and feeding/fasting rhythms. Since we found that (1) the number of NONO-containing speckles increases in response to feeding, (2) NONO interacts with RNA processing factors and (3) it binds to the introns of a large number of protein coding genes, we hypothesized that NONO may contribute to the daily rhythm of hepatic gene expression. To address whether NONO contributes to rhythmic gene expression in response to feeding/fasting, diurnal liver transcriptomes were assessed in nono-/- and wt littermate mice fed a normal diet during the night time (ZT12-24). We habituated mice to a 12:12 LD cycle with food available only at lights off (ZT12-24) for one week and in the second week collected mice every 2h throughout the 24h day. Both total and nuclear RNAs were sequenced after ribosomal RNA depletion
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:Hepatocyte nuclei were purified from liver samples harvested from HMGB1fl/fl (n=2) and HMGB1ΔHep (n=2) mice upon chow diet feeding or after fasting-refeeding.
Project description:Using an "omics"-based approach, we investigated the interaction between the autonomous liver clock and feeding-fasting rhythm. Transcriptomic analysis and subsequent quantification of exonic and intronic reads revealed that transcriptional mechanisms mediate, at least in part, the integration of feeding signals by the liver clock to drive mRNA oscillations. Therefore, we performed ATAC-seq to probe the state of chromatin accessibility genome-wide. While most open chromatin regions are unchanged across genotype, time and feeding status, transcription factor (TFs) footprints showed altered activity of certain TFs in Liver-RE AL vs NF. For example, CEBPB activity is altered in Liver-RE AL and restored in NF, an observation accompanied by restored CEBPB and BMAL1 common target gene oscillations. Finally, metabolomics analysis illustrated the partial rescue of hepatic metabolism in Liver-RE NF compared to AL (extensive carbohydrate pathway oscillations), and made clear that extra-hepatic clocks contribute significantly to metabolic oscillations in the liver, particularly for pathways involving lipids. Please see the associated reference for full results.
Project description:Using an "omics"-based approach, we investigated the interaction between the autonomous liver clock and feeding-fasting rhythm. Transcriptomic analysis and subsequent quantification of exonic and intronic reads revealed that transcriptional mechanisms mediate, at least in part, the integration of feeding signals by the liver clock to drive mRNA oscillations. Therefore, we performed ATAC-seq to probe the state of chromatin accessibility genome-wide. While most open chromatin regions are unchanged across genotype, time and feeding status, transcription factor (TFs) footprints showed altered activity of certain TFs in Liver-RE AL vs NF. For example, CEBPB activity is altered in Liver-RE AL and restored in NF, an observation accompanied by restored CEBPB and BMAL1 common target gene oscillations. Finally, metabolomics analysis illustrated the partial rescue of hepatic metabolism in Liver-RE NF compared to AL (extensive carbohydrate pathway oscillations), and made clear that extra-hepatic clocks contribute significantly to metabolic oscillations in the liver, particularly for pathways involving lipids. Please see the associated reference for full results.
Project description:The aim was to investigate transcriptional differences between circulating Ly6Chi monocytes under feeding and fasting/re-feeding conditions Ly6Chi monocytes were sorted from blood after contious feeding or after a 24h fast follwed by a four hour re-feeding period
Project description:Nutrient availability fluctuates in most natural populations, forcing organisms to undergo periods of fasting and re-feeding. It is unknown how dietary change influences liver homeostasis. Here, we show that a switch from ad libitum feeding to intermittent fasting (IF) promotes rapid hepatocyte proliferation. Mechanistically, IF- induced hepatocyte proliferation is driven by the combined action of intestinally produced, systemic endocrine FGF15 and localized WNT signaling. IF proliferation re-establishes a constant liver-to-body-mass ratio during periods of fasting and re-feeding, a process termed the hepatostat. This study provides the first example of dietary influence on adult hepatocyte proliferation, and challenges the widely held view that liver tissue is mostly quiescent unless chemically or mechanically injured.
Project description:In order to understand the role of heterodimeric hypoxia-inducible factors (HIF) in non-alcoholic fatty liver disease, we subjected wild type and Hif1-alpha mutant mice to nutritional stress conditions imposed by switching from fasting to re-feeding. Liver samples and subsequently RNA were extracted at each time point and used to comprehensively characterise transcriptional changes using microarray technology. We provide biological replicates for each of the conditions.
Project description:The liver is key for maintaining metabolic homeostasis between feeding and fasting in healthy conditions. However, this is dysregulated during high fat diet feeding. What are the transcriptomic changes required for rapid adaptation of the liver to respond to feeding and fasting and how is this altered in the development of metabolic disease?