Dissecting the autonomy of the liver circadian clock
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE117134 | GEO | 2019/06/11
REPOSITORIES: GEO
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Project description:Virtually every mammalian tissue exhibits rhythmic expression in thousands of genes, which activate tissue-specific processes at appropriate times of the day. Much of this rhythmic expression is thought to be driven cell-autonomously by molecular circadian clocks present throughout the body. However, increasing evidence suggests that systemic signals, and more specifically rhythmic food intake (RFI), can regulate rhythmic gene expression independently of the circadian clock. To determine the relative contribution of cell autonomous clocks versus RFI in the regulation of rhythmic gene expression, we developed a system that allows long-term manipulation of the daily rhythm of food intake in the mouse, and analyzed liver gene expression by RNA-Seq in mice fed ad libitum, only at night, or arrhythmically (mouse eating 1/8th of their daily food intake every 3 hours). We show that 70% of the cycling mouse liver transcriptome loses rhythmicity under arrhythmic feeding. Remarkably, this loss of rhythmic gene expression under arrhythmic feeding is independent of the liver circadian clock, which continues to exhibit normal oscillations in core clock gene expression. Many genes that lose rhythmicity participate in the regulation of metabolic processes such as lipogenesis and glycogenesis, likely contributing to an increased sensitivity to insulin that was observed in arrhythmically-fed mice. We also show that night-restricted feeding significantly increases the number of rhythmically expressed genes as well as the amplitude of the rhythms. Together, these results indicate that metabolic transcription factors control a large fraction of the rhythmic mouse liver transcriptome, and demonstrate that systemic signals driven by rhythmic food intake play a more important role than the cell-autonomous circadian clock in driving rhythms in liver gene expression and metabolic functions.
2019-04-25 | GSE118967 | GEO
Project description:Most cells in the body contain a cell autonomous molecular clock, but the requirement of peripheral clocks for circadian rhythmicity, and their effects on physiology, are not well understood. Here we show that deletion of core clock components REV-ERBa and b in adult mouse hepatocytes caused the loss of circadian rhythmicity of many liver genes, as expected, but also led to maintained and even gained rhythmicity of other genes without altering feeding behavior. The loss of REV-ERBs from hepatocytes leads to an exaggerated circadian rhythm of de novo lipogenesis and serum triglyceride levels. It is increasingly recognized that liver function is also influenced by non-hepatocytic cells, and remarkably the loss of REV-ERBs in hepatocytes remodeled the circadian transcriptomes of multiple cell types within the liver without altering their core clocks, indicating that hepatocytes communicated time signals to the non-hepatocytic cells. Finally, alteration of food availability, which is the dominant zeitgeber in the liver, demonstrated strong interdependence of the cell-autonomous hepatocyte clock mechanism and non-cell-autonomous environmental change. Together these studies reveal the interdependence of endogenous hepatocyte clocks and feeding entrainment on the regulation of circadian rhythms of multiple cell types in the liver.
2020-07-30 | GSE143526 | GEO
Project description:Most cells in the body contain a cell autonomous molecular clock, but the requirement of peripheral clocks for circadian rhythmicity, and their effects on physiology, are not well understood. Here we show that deletion of core clock components REV-ERBa and b in adult mouse hepatocytes caused the loss of circadian rhythmicity of many liver genes, as expected, but also led to maintained and even gained rhythmicity of other genes without altering feeding behavior. The loss of REV-ERBs from hepatocytes leads to an exaggerated circadian rhythm of de novo lipogenesis and serum triglyceride levels. It is increasingly recognized that liver function is also influenced by non-hepatocytic cells, and remarkably the loss of REV-ERBs in hepatocytes remodeled the circadian transcriptomes of multiple cell types within the liver without altering their core clocks, indicating that hepatocytes communicated time signals to the non-hepatocytic cells. Finally, alteration of food availability, which is the dominant zeitgeber in the liver, demonstrated strong interdependence of the cell-autonomous hepatocyte clock mechanism and non-cell-autonomous environmental change. Together these studies reveal the interdependence of endogenous hepatocyte clocks and feeding entrainment on the regulation of circadian rhythms of multiple cell types in the liver.
2020-07-30 | GSE143525 | GEO
Project description:Most cells in the body contain a cell autonomous molecular clock, but the requirement of peripheral clocks for circadian rhythmicity, and their effects on physiology, are not well understood. Here we show that deletion of core clock components REV-ERBa and b in adult mouse hepatocytes caused the loss of circadian rhythmicity of many liver genes, as expected, but also led to maintained and even gained rhythmicity of other genes without altering feeding behavior. The loss of REV-ERBs from hepatocytes leads to an exaggerated circadian rhythm of de novo lipogenesis and serum triglyceride levels. It is increasingly recognized that liver function is also influenced by non-hepatocytic cells, and remarkably the loss of REV-ERBs in hepatocytes remodeled the circadian transcriptomes of multiple cell types within the liver without altering their core clocks, indicating that hepatocytes communicated time signals to the non-hepatocytic cells. Finally, alteration of food availability, which is the dominant zeitgeber in the liver, demonstrated strong interdependence of the cell-autonomous hepatocyte clock mechanism and non-cell-autonomous environmental change. Together these studies reveal the interdependence of endogenous hepatocyte clocks and feeding entrainment on the regulation of circadian rhythms of multiple cell types in the liver.
2020-07-30 | GSE143524 | GEO
Project description:The mammalian circadian system consists of a central clock in the brain that synchronizes clocks in peripheral tissues. While the hierarchy between the central and peripheral clocks is well established, peripheral clocks are largely viewed as a group and little is known regarding their specificity and functional organization. We employed feeding paradigms in conjunction with liver-specific clock-deficient murine model to map disparities and potential interactions between peripheral clocks. We found that peripheral clocks largely differ in their response to feeding-time. In view of its prominent role in nutrient processing, we hypothesized that the liver-clock instigate the response of peripheral clocks to feeding. Although the liver-clock did not affect the rhythmicity of clocks in other peripheral tissues, it strongly modulated their transcriptional rhythmicity upon daytime feeding. Overall, our findings suggest a role for the liver-clock in buffering feeding-related signals that affect rhythmicity of other peripheral tissues upon nutrient challenge, irrespective of their clocks.
2021-01-29 | GSE159135 | GEO
Project description:Rhythmic intraorgan communication coordinates environmental signals and cell-intrinsic clock to maintain organ homeostasis. Hepatocyte-specific knockout of core components of the molecular clock, Rev-erba and b (ReverbhDKO), alters cholesterol and lipid metabolism in hepatocytes as well as rhythmic gene expression in non-parenchymal cells (NPC) of the liver. Here we report that in diet induced obesity (DIO)-caused fatty liver, hepatocyte SREBP cleavage-activating protein (SCAP) is required for ReverbhDKO-induced diurnal rhythmic remodeling and epigenomic reprogramming in Kupffer cells (KC). Integrative analyses of isolated hepatocytes and Kupffer cells uncovered potential signals, including secreted polypeptides and metabolites, that gain rhythmicity in the absence of REV-ERBs in a SCAP-dependent manner. These results shed light on the signaling mechanisms by which hepatocytes regulate diurnal rhythms in NPCs in DIO and fatty liver disease.
2023-04-04 | GSE206318 | GEO
Project description:Rhythmic intraorgan communication coordinates environmental signals and cell-intrinsic clock to maintain organ homeostasis. Hepatocyte-specific knockout of core components of the molecular clock, Rev-erba and b (ReverbhDKO), alters cholesterol and lipid metabolism in hepatocytes as well as rhythmic gene expression in non-parenchymal cells (NPC) of the liver. Here we report that in diet induced obesity (DIO)-caused fatty liver, hepatocyte SREBP cleavage-activating protein (SCAP) is required for ReverbhDKO-induced diurnal rhythmic remodeling and epigenomic reprogramming in Kupffer cells (KC). Integrative analyses of isolated hepatocytes and Kupffer cells uncovered potential signals, including secreted polypeptides and metabolites, that gain rhythmicity in the absence of REV-ERBs in a SCAP-dependent manner. These results shed light on the signaling mechanisms by which hepatocytes regulate diurnal rhythms in NPCs in DIO and fatty liver disease.
2023-04-04 | GSE206317 | GEO
Project description:Rhythmic intraorgan communication coordinates environmental signals and cell-intrinsic clock to maintain organ homeostasis. Hepatocyte-specific knockout of core components of the molecular clock, Rev-erba and b (ReverbhDKO), alters cholesterol and lipid metabolism in hepatocytes as well as rhythmic gene expression in non-parenchymal cells (NPC) of the liver. Here we report that in diet induced obesity (DIO)-caused fatty liver, hepatocyte SREBP cleavage-activating protein (SCAP) is required for ReverbhDKO-induced diurnal rhythmic remodeling and epigenomic reprogramming in Kupffer cells (KC). Integrative analyses of isolated hepatocytes and Kupffer cells uncovered potential signals, including secreted polypeptides and metabolites, that gain rhythmicity in the absence of REV-ERBs in a SCAP-dependent manner. These results shed light on the signaling mechanisms by which hepatocytes regulate diurnal rhythms in NPCs in DIO and fatty liver disease.
2023-04-04 | GSE206316 | GEO
Project description:Mammals rely on a network of circadian clocks to control daily systemic metabolism and physiology. The central pacemaker in the suprachiasmatic nucleus (SCN) is considered hierarchically dominant over peripheral clocks, whose degree of independence, or tissue-level autonomy, has never been ascertained in vivo. Using arrhythmic Bmal1-null mice, we generated animals with reconstituted circadian expression of BMAL1 exclusively in the liver (Liver-RE). High-throughput transcriptomics and metabolomics show that the liver has independent circadian functions specific for metabolic processes such as the NAD+ salvage pathway and glycogen turnover. However, although BMAL1 occupies chromatin at most genomic targets in Liver-RE mice, circadian expression is restricted to ∼10% of normally rhythmic transcripts. Finally, rhythmic clock gene expression is lost in Liver-RE mice under constant darkness. Hence, full circadian function in the liver depends on signals emanating from other clocks, and light contributes to tissue-autonomous clock function.
2019-06-13 | GSE132659 | GEO
Project description:The circadian clock and rhythmic food intake are both important regulators of rhythmic gene expression in the liver. It remains, however, elusive to which extent the circadian clock network and natural feeding rhythms contribute to rhythmic gene expression. To systematically address this question, we developed an algorithm to investigate differential rhythmicity between a varying number of conditions. Mouse knockout models of different parts of the circadian clock network (Bmal1, Cry1/2, and Hlf/Dbp/Tef) exposed to controlled feeding regimens (ad libitum, night restricted feeding) were generated and analyzed for their temporal hepatic transcriptome. A genetical ablation of core loop elements altered feeding patterns that were restored by night restricted feeding. Mainly genes with a high amplitude were driven by the circadian clock but natural feeding patterns equally contributed to rhythmic gene expression with lower amplitude. We observed that Bmal1 and Cry1/2 KOs differed in rhythmic gene expression and identified differences in mean expression levels as a predictor for rhythmic gene expression. In Hlf/Dbp/Tef KO, mRNA levels of Hlf/Dbp/Tef target genes were decreased, albeit rhythmicity was overall preserved potentially due to the activity of the D-Box binding repressor NFIL3. Genes that lost rhythmicity in Hlf/Dbp/Tef KOs were identified to be no direct targets of PARbZip factors and presumably lost rhythmicity due to indirect effects. Collectively, our findings provide unprecedent insights into the diurnal transcriptome in mouse liver and defines the contribution of subloops of the circadian clock network and natural feeding cycles. The developed algorithm and a webapp to browse the outcomes of the study are publicly available to serve as a resource for the scientific community.
2020-12-03 | GSE135898 | GEO