Similar Datasets
Project description:The 12-hour clock coordinates lipid homeostasis, energy metabolism and stress rhythms via the transcriptional regulator XBP1. However, the biochemical and physiological basis for integrated control of the 12-hour clock and diverse metabolic pathways remains unclear. Here, we show that steroid receptor coactivator SRC-3 coactivates XBP1 transcription and regulates hepatic 12-hour cistrome and gene rhythmicity. Mice lacking SRC-3 show abnormal 12-hour rhythms in hepatic transcription, metabolic functions, systemic energetics, and rate-limiting lipid metabolic processes including triglyceride, phospholipid and cardiolipin pathways. Notably, 12-hour clock coactivation is not only preserved, with its cistromic activation priming ahead of the zeitgeber cue of light, but concomitant with rhythmic remodeling in the absence of food. These findings reveal that SRC-3 integrates the mammalian 12-hour clock, energy metabolism, and membrane and lipid homeostasis, and demonstrates a role for the 12-hour clock machinery as an active transcriptional mechanism in anticipating physiological and metabolic energy needs and stresses.
2022-02-04 | ST002079 | MetabolomicsWorkbench
Project description:Defining the mammalian coactivation of hepatic 12-hour clock and lipid metabolism
| PRJNA733045 | ENA
Project description:A distinct 12-hour clock exists in addition to the 24-hour circadian clock to coordinate metabolic and stress rhythms. Here, we show that liver-specific ablation of X-box binding protein 1 (XBP1) disrupts the hepatic 12-hour clock and promotes spontaneous non-alcoholic fatty liver disease (NAFLD). We show that hepatic XBP1 predominantly regulates the 12-hour rhythmicity of gene transcription in the mouse liver and demonstrate that perturbation of the 12-hour clock, but not the core circadian clock, is associated with the onset and progression of this NAFLD phenotype. Mechanistically, we provide evidence that the spliced form of XBP1 (XBP1s) binds to the hepatic 12-hour cistrome to directly regulate the 12-hour clock, with a periodicity paralleling the harmonic activation of the 12-hour oscillatory transcription of many rate-limiting metabolic genes known to have perturbations in human metabolic disease. Functionally, we show that Xbp1 ablation significantly reduces cellular membrane fluidity and impairs lipid homeostasis via rate-limiting metabolic processes in fatty acid monounsaturated and phospholipid remodeling pathways. These findings reveal that genetic disruption of the hepatic 12-hour clock links to the onset and progression of NAFLD development via transcriptional regulator XBP1, and demonstrate a role for XBP1 and the 12-hour clock in the modulation of phospholipid composition and the maintenance of lipid homeostasis.
| S-EPMC7718229 | biostudies-literature
Project description:Impaired mitochondrial function has been implicated in the pathogenesis of type 2 diabetes, heart failure, and neurodegeneration as well as during aging. Studies with the PGC-1 transcriptional coactivators have demonstrated that these factors are central components of the regulatory network that controls mitochondrial function in mammalian cells. Here we describe a genome-wide coactivation assay to globally identify transcription factors and cofactors in this pathway. These analyses revealed a molecular signature of the PGC-1alpha transcriptional network and identified BAF60a (SMARCD1) as a molecular link between the SWI/SNF chromatin-remodeling complexes and hepatic lipid metabolism. Adenoviral-mediated expression of BAF60a stimulates fatty acid beta-oxidation in cultured hepatocytes and ameliorates hepatic steatosis in vivo. PGC-1alpha mediates the recruitment of BAF60a to PPARalpha-binding sites, leading to transcriptional activation of peroxisomal and mitochondrial fat-oxidation genes. These results define a role for the SWI/SNF complexes in the regulation of lipid homeostasis.
| S-EPMC2578827 | biostudies-literature
Project description:Hyperlipidemia is a key clinical feature in patients with nephrotic syndrome (NS) that is associated with the incidence of cardiovascular events. Recent studies have suggested that the disorders of triglycerides, gluconeogenesis and liver glucose metabolism are associated with the abnormal transcription of clock genes. However, changes to the circadian rhythm of blood lipids in NS require further exploration, and the effects of NS on the hepatic clock system remain to be elucidated. In the present study, the impaired diurnal rhythm of the hepatic core clock genes (BMAL1, CLOCK, CRY1, CRY2, PER1 and PER2) significantly induced circadian rhythm abnormalities in liver‑specific clock‑controlled genes (LXR, CYP7A1, SREBP‑1, ABCA1, DEC1 and DEC2; all P<0.05), which were significantly associated with the abnormal diurnal rhythms of triglyceride, total cholesterol, aspartate aminotransferase and alanine aminotransferase (all P<0.05) in rats with Adriamycin‑induced nephropathy. Furthermore, a protein‑protein interaction network was identified. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses based on the human database was conducted to obtain signaling pathway and correlation prediction analyses of overall human clock and clock‑controlled gene correlations. Strong correlations of the aforementioned clock genes were detected (avg. local clustering coefficient, 0.849) which suggested significant enrichment in circadian rhythm signaling. The present results indicated that damage to hepatic clock systems may impact blood lipid circadian rhythm disorders in NS, and offer a starting point for understanding the crosstalk between peripheral organs and peripheral clock systems.
| S-EPMC6192718 | biostudies-literature
Project description:Transcriptional regulation of circadian rhythms is essential for lipid metabolic homeostasis, disruptions of which can lead to metabolic diseases. Whether N6-methyladenosine (m6A) mRNA methylation impacts circadian regulation of lipid metabolism is unclear. Here, we show m6A mRNA methylation oscillations in murine liver depend upon a functional circadian clock. Hepatic deletion of Bmal1 increases m6A mRNA methylation, particularly of PPaRα. Inhibition of m6A methylation via knockdown of m6A methyltransferase METTL3 decreases PPaRα m6A abundance and increases PPaRα mRNA lifetime and expression, reducing lipid accumulation in cells in vitro. Mechanistically, YTHDF2 binds to PPaRα to mediate its mRNA stability to regulate lipid metabolism. Induction of reactive oxygen species both in vitro and in vivo increases PPaRα transcript m6A levels, revealing a possible mechanism for circadian disruption on m6A mRNA methylation. These data show that m6A RNA methylation is important for circadian regulation of downstream genes and lipid metabolism, impacting metabolic outcomes.
| S-EPMC6532766 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2016-06-29 | E-GEOD-83791 | biostudies-arrayexpress
Project description:Circadian transcriptional rhythms are necessary for lipid metabolic homeostasis. Disruptions can lead to metabolic diseases. Whether epigenetic N6-methyladenosine (m6A) mRNA methylation impacts circadian regulation of lipid metabolism is unclear. Here, we show m6A mRNA methylation oscillations in murine liver depend upon a functional circadian clock. Hepatic deletion of Bmal1 increased m6A mRNA methylation, particularly of PPaRα. Inhibition of m6A methylation via knockdown of m6A methyltransferase METTL3 decreased PPaRα m6A abundance and increased PPaRα mRNA lifetime and expression, reducing lipid accumulation in cells in vitro. Our data suggest YTH domain family 2 (YTHDF2, a m6A binding protein) binds to PPaRα, prolonging its lifetime and mRNA expression. Reactive oxygen species accumulation increased PPaRα transcript m6A levels, revealing a possible mechanism for circadian clock disruption on m6A mRNA methylation. These data suggest m6A RNA methylation is important for circadian clock regulation of downstream genes and lipid metabolism that impacts metabolic outcome.
2018-06-21 | GSE102620 | GEO
Project description:The circadian clock generates daily cycles of gene expression that regulate physiological processes. The liver plays an important role in xenobiotic metabolism and also has been shown to possess its own cell-based clock. The liver clock is synchronized by the master clock in the brain, and a portion of rhythmic gene expression can be driven by behavior of the organism as a whole even when the hepatic clock is suppressed. So far, however, there is relatively little evidence indicating whether the liver clock is functionally important in modulating xenobiotic metabolism. Thus, mice lacking circadian clock function in the whole body or specifically in liver were challenged with pentobarbital and acetaminophen, and pentobarbital sleep time (PBST) and acetaminophen toxicity, respectively, was assessed at different times of day in mutant and control mice. The results suggest that the liver clock is essential for rhythmic changes in xenobiotic detoxification. Surprisingly, it seems that the way in which the clock is disrupted determines the rate of xenobiotic metabolism in the liver. CLOCK-deficient mice are remarkably resistant to acetaminophen and exhibit a longer PBST, while PERIOD-deficient mice have a short PBST. These results indicate an essential role of the tissue-intrinsic peripheral circadian oscillator in the liver in regulating xenobiotic metabolism.
| S-EPMC4346587 | biostudies-literature
Project description:Alcoholic liver disease (ALD) is the most prevalent type of chronic liver disease with significant morbidity and mortality worldwide. ALD begins with simple hepatic steatosis and progresses to alcoholic steatohepatitis, fibrosis, and cirrhosis. The severity of hepatic steatosis is highly associated with the development of later stages of ALD. This review explores the disturbances of alcohol-induced hepatic lipid metabolism through altered hepatic lipid uptake, de novo lipid synthesis, fatty acid oxidation, hepatic lipid export, and lipid droplet formation and catabolism. In addition, we review emerging data on the contributions of genetics and bioactive lipid metabolism in alcohol-induced hepatic lipid accumulation.
| S-EPMC7112138 | biostudies-literature