Transcriptional profiling of PPARα-/- and CREB3L3-/- livers reveals disparate regulation of hepatoproliferative and metabolic functions of PPARα
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PROVIDER: PRJNA495632 | ENA |
REPOSITORIES: ENA
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Project description:Peroxisome Proliferator-Activated receptor α (PPARα) and cAMP-Responsive Element Binding Protein 3-Like 3 (CREB3L3) are transcription factors involved in the regulation of lipid metabolism in the liver. The aim of the present study was to characterize the interrelationship between PPARα and CREB3L3 in regulating hepatic gene expression. Male wildtype, PPARα-/-, CREB3L3-/- and combined PPARα/CREB3L3-/- mice were subjected to a 16-hour fast or 4 days of ketogenic diet. Whole genome expression analysis was performed on liver samples. Under conditions of overnight fasting, the effects of PPARα ablation and CREB3L3 ablation on plasma triglyceride, plasma β-hydroxybutyrate, and hepatic gene expression were largely disparate, and showed only limited interdependence. Gene and pathway analysis underscored the importance of CREB3L3 in regulating (apo)lipoprotein metabolism, and of PPARα as master regulator of intracellular lipid metabolism. A small number of genes, including Fgf21 and Mfsd2a, were under dual control of PPARα and CREB3L3. By contrast, a strong interaction between PPARα and CREB3L3 ablation was observed during ketogenic diet feeding. Specifically, the pronounced effects of CREB3L3 ablation on liver damage and hepatic gene expression during ketogenic diet were almost completely abolished by the simultaneous ablation of PPARα. Loss of CREB3L3 influenced PPARα signalling in two major ways. Firstly, it reduced expression of PPARα and its target genes involved in fatty acid oxidation and ketogenesis. In stark contrast, the hepatoproliferative function of PPARα was markedly activated by loss of CREB3L3. These data indicate that CREB3L3 ablation uncouples the hepatoproliferative and lipid metabolic effects of PPARα. Overall, except for the shared regulation of a very limited number of genes, the roles of PPARα and CREB3L3 in hepatic lipid metabolism are clearly distinct and are highly dependent on dietary status.
2019-01-23 | GSE121096 | GEO
Project description:BackgroundPeroxisome Proliferator-Activated receptor α (PPARα) and cAMP-Responsive Element Binding Protein 3-Like 3 (CREB3L3) are transcription factors involved in the regulation of lipid metabolism in the liver. The aim of the present study was to characterize the interrelationship between PPARα and CREB3L3 in regulating hepatic gene expression. Male wild-type, PPARα-/-, CREB3L3-/- and combined PPARα/CREB3L3-/- mice were subjected to a 16-h fast or 4 days of ketogenic diet. Whole genome expression analysis was performed on liver samples.ResultsUnder conditions of overnight fasting, the effects of PPARα ablation and CREB3L3 ablation on plasma triglyceride, plasma β-hydroxybutyrate, and hepatic gene expression were largely disparate, and showed only limited interdependence. Gene and pathway analysis underscored the importance of CREB3L3 in regulating (apo)lipoprotein metabolism, and of PPARα as master regulator of intracellular lipid metabolism. A small number of genes, including Fgf21 and Mfsd2a, were under dual control of PPARα and CREB3L3. By contrast, a strong interaction between PPARα and CREB3L3 ablation was observed during ketogenic diet feeding. Specifically, the pronounced effects of CREB3L3 ablation on liver damage and hepatic gene expression during ketogenic diet were almost completely abolished by the simultaneous ablation of PPARα. Loss of CREB3L3 influenced PPARα signalling in two major ways. Firstly, it reduced expression of PPARα and its target genes involved in fatty acid oxidation and ketogenesis. In stark contrast, the hepatoproliferative function of PPARα was markedly activated by loss of CREB3L3.ConclusionsThese data indicate that CREB3L3 ablation uncouples the hepatoproliferative and lipid metabolic effects of PPARα. Overall, except for the shared regulation of a very limited number of genes, the roles of PPARα and CREB3L3 in hepatic lipid metabolism are clearly distinct and are highly dependent on dietary status.
| S-EPMC6416987 | biostudies-literature
Project description:Phosphatidylcholine transfer protein (PC-TP, a.k.a StarD2) is abundantly expressed in liver and is regulated by PPARα. When fed the synthetic PPARα ligand fenofibrate, Pctp-/- mice exhibited altered lipid and glucose homeostasis. Microarray profiling of liver from fenofibrate fed wild type and Pctp-/- mice revealed differential expression of a broad array of metabolic genes, as well as their regulatory transcription factors. Because its expression controlled the transcriptional activities of both PPARα and HNF4α in cell culture, the broader impact of PC-TP on nutrient metabolism is most likely secondary to its role in fatty acid metabolism. 6 livers collected from PC-TP knockout mice fed a fenobrate-supplemented diet were used as the experimental group. 6 livers collected from wild type mice fed a fenofibrate-supplemented diet were used as the control group. RNA prepared from one liver was used to hybridize one GeneChip, so that there were 6 experimental GeneChips and 6 control GeneChips.
2010-08-12 | E-GEOD-17666 | biostudies-arrayexpress
Project description:The role of PPARα in gene regulation in mouse liver is well characterized. However, less is known about the effect of PPARα activation in human liver. The aim of the present study was to better characterize the impact of PPARα activation on gene regulation in human liver by combining transcriptomics with the use of hepatocyte humanized livers. To that end, chimeric mice containing hepatocyte humanized livers were given an oral dose of 300 mg/kg fenofibrate daily for 4 days. Livers were collected and analysed by hematoxilin and eosin staining, qPCR, and transcriptomics. Transcriptomics data were compared with existing datasets on fenofibrate treatment in normal mice. The human hepatocytes exhibited excessive lipid accumulation. Fenofibrate increased the size of the mouse but not human hepatocytes, and tended to reduce steatosis in the human hepatocytes. Quantitative PCR indicated that induction of PPARα targets by fenofibrate was less pronounced in the human hepatocytes than in the residual mouse hepatocytes. Transcriptomics analysis indicated that, after filtering, a total of 282 genes was significantly different between fenofibrate- and control-treated mice (P<0.01). 123 genes were significantly lower and 159 genes significantly higher in the fenofibrate-treated mice, including many established PPARα targets such as FABP1, HADHB, HADHA, VNN1, PLIN2, ACADVL and HMGCS2. According to gene set enrichment analysis, fenofibrate upregulated interferon/cytokine signaling-related pathways in hepatocyte humanized liver, but downregulated these pathways in normal mouse liver. Also, fenofibrate downregulated pathways related to DNA synthesis in hepatocyte humanized liver but not in normal mouse liver. The results support the major role of PPARα in regulating hepatic lipid metabolism, and underscore the more modest effect of PPARα activation on gene regulation in human liver compared to mouse liver. The data suggest that PPARα may have a suppressive effect on DNA synthesis in human liver, and a stimulatory effect on interferon/cytokine signalling.
2018-05-28 | GSE107041 | GEO
Project description:Despite decades of research, sepsis remains one of the most urgent unmet medical needs. Clinical trials in sepsis have mainly focused on targeting the inflammatory pathway, however, recent data indicate that sepsis should also be seen as a metabolic disease. Targeting metabolic dysregulations that take place in sepsis might uncover novel therapeutic opportunities to treat human sepsis patients. The role of PPARα in liver dysfunction during sepsis has recently been described, and restoring PPARα signaling proves to be successful in murine sepsis. To find out whether this therapy might also be helpful in human sepsis patients, we analyzed metabolic perturbations in liver of a porcine fecal peritonitis model. Resuscitation with fluids, antimicrobial therapy and abdominal drainage were applied to the pigs in order to mimic human clinical care. By using RNA-seq, we detected problems with PPARα signaling in the livers of septic pigs and reduced PPARα levels correlated well with disease severity. As PPARα regulates the expression of many genes involved in FA oxidation, reduced expression of these target genes concomitant with increased FFAs in plasma and ectopic lipid deposition in the liver was observed. The results obtained in pigs are in agreement with earlier observations in mice and support the potential of targeting defective PPARα signaling in the clinic.
2022-11-28 | GSE218636 | GEO
Project description:Nuclear receptor activation in liver leads to coordinated alteration of the expression of multiple gene products with attendant phenotypic changes of hepatocytes. Peroxisome proliferators including endogenous fatty acids, environmental chemicals, and drugs induce a multi-enzyme metabolic response that affects lipid and fatty acid processing. We studied the signaling network for the peroxisome proliferator-associated receptor alpha (PPARα) in primary human hepatocytes using the selective PPARα ligand, GW7647. We measured gene expression over multiple concentrations and times and conducted ChIP-seq studies at 2 and 24 hours to assess genomic binding of PPARα. Over all treatments there were 192 genes differentially expressed. Of these only 51% showed evidence of PPARα binding – either directly at PPARα response elements or via alternative mechanisms. Almost half of regulated genes had no PPARα binding. We then developed two novel bioinformatics methods to visualize the dose-dependent activation of both the transcription factor circuitry for PPARα and the downstream metabolic network in relation to functional annotation categories. Available databases identified several key transcription factors involved with the non-genomic targets after GW7647 treatment, including SP1, STAT1, ETS1, ERα, and HNF4α. The linkage from PPARα binding through gene expression likely requires intermediate protein kinases to activate these transcription factors. We found enrichment of functional annotation categories for organic acid metabolism and cell lipid metabolism among the differentially expressed genes. Lipid transport processes showed enrichment at the highest concentration of GW7647 (10μM). While our strategy for mapping transcriptional networks is evolving, these approaches are necessary in moving from toxicogenomic methods that derive signatures of activity to methods that establish pathway structure, showing the coordination of the activated nuclear receptor with other signaling pathways. Primary hepatocytes from four donors were exposed to 0, 0.001, 0.01, 0.1, 1.0, or 10.0μM GW7647 for 2, 6, 12, 24, or 72 hours.
2013-12-18 | E-GEOD-53399 | biostudies-arrayexpress
Project description:Autophagy is an evolutionally conserved catabolic process that recycles nutrients upon starvation and maintains cellular energy homeostasis1-3. Its acute regulation by nutrient sensing signaling pathways is well described, but its longer-term transcriptional regulation is not. The nuclear receptors PPARα and FXR are activated in the fasted or fed liver, respectively4,5. Here we show that both regulate hepatic autophagy. Pharmacologic activation of PPARα reverses the normal suppression of autophagy in the fed state, inducing autophagic lipid degradation, or lipophagy. This response is lost in PPARα knockout (PPARα-/-) mice, which are partially defective in the induction of autophagy by fasting. Pharmacologic activation of the bile acid receptor FXR strongly suppresses the induction of autophagy in the fasting state, and this response is absent in FXR knockout (FXR-/-) mice, which show a partial defect in suppression of hepatic autophagy in the fed state. PPARα and FXR compete for binding to shared sites in autophagic gene promoters, with opposite transcriptional outputs. These results reveal complementary, interlocking mechanisms for regulation of autophagy by nutrient status. Mouse liver PPARα cistromes in fed 8-week-old male WT or PPARα KO mice treated with or without its synthetic agonist ligand GW7647twice a day were generated by deep sequencing in quadruplicate using illumina
2014-09-27 | E-GEOD-61817 | biostudies-arrayexpress
Project description:Diet plays a crucial role in shaping human health and disease. Diets promoting obesity and insulin resistance can lead to severe metabolic diseases, while calorie-restricted (CR) diets can improve health and extend lifespan. In this work, we fed mice either a chow diet (CD), a 16 week high-fat diet (HFD), or a CR diet to compare and contrast the effects of these diets on mouse liver biology. We collected transcriptomic and epigenomic datasets from these mice using RNA-Seq and DNase-Seq. We found that both CR and HFD induce extensive transcriptional changes, in some cases altering the same genes in the same direction. We used our epigenomic data to infer transcriptional regulatory proteins bound near these genes that likely influence their expression levels. In particular, we found evidence for critical roles played by PPARα and RXRα. We used ChIP-Seq to profile the binding locations for these factors in HFD and CR livers. We found extensive binding of PPARα near genes involved in glycolysis/gluconeogenesis and uncovered a role for this factor in regulating anaerobic glycolysis. Overall, we generated extensive transcriptional and epigenomic datasets from livers of mice fed these diets and uncovered new functions and gene targets for PPARα.
2017-03-15 | GSE47954 | GEO
Project description:Phosphatidylcholine transfer protein (PC-TP, a.k.a StarD2) is abundantly expressed in liver and is regulated by PPARα. When fed the synthetic PPARα ligand fenofibrate, Pctp-/- mice exhibited altered lipid and glucose homeostasis. Microarray profiling of liver from fenofibrate fed wild type and Pctp-/- mice revealed differential expression of a broad array of metabolic genes, as well as their regulatory transcription factors. Because its expression controlled the transcriptional activities of both PPARα and HNF4α in cell culture, the broader impact of PC-TP on nutrient metabolism is most likely secondary to its role in fatty acid metabolism.
2010-08-12 | GSE17666 | GEO
Project description:The class 3 phosphoinositide 3-kinase (PI3K) is required for the lysosomal degradation by autophagy and vesicular trafficking, assuring adaptation to energy shortages. Mitochondrial lipid catabolism is another important energy source. Autophagy and mitochondrial metabolism are transcriptionally controlled by nutrient sensing nuclear receptors. However, it is not known whether the class 3 PI3K contributes to this regulation. Here we show that hepatocyte-specific inactivation of Vps15, the essential regulatory subunit of the class 3 PI3K, results in mitochondrial depletion and a failure to oxidize fatty acids. Mechanistically, the transcriptional activity of Peroxisome Proliferator Activated Receptor alpha (PPARα), a nuclear receptor that orchestrates fatty acid catabolism, is blunted in Vps15-deficient livers. We find PPARα transcriptional repressors Histone Deacetylase 3 (Hdac3) and Nuclear receptor co-repressor 1 (NCoR1) accumulated in Vps15-deficient livers due to defective autophagic flux. Pharmacologic activation of PPARα with a synthetic ligand, re-expression of its co-activator Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha (PGC-1α) or inhibition of Hdac3 restored mitochondrial biogenesis and lipid oxidation in Vps15-deficient hepatocytes. These findings reveal a role for the class 3 PI3K and autophagy in transcriptional coordination of mitochondrial metabolism.
2020-02-06 | E-MTAB-7685 | biostudies-arrayexpress