PPARα activation promotes liver progenitor cell-mediated liver regeneration by suppressing YAP signaling in zebrafish
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ABSTRACT:
ORGANISM(S): Danio rerio
PROVIDER: GSE226923 | GEO | 2023/07/01
REPOSITORIES: GEO
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Project description:PPARα activation promotes liver progenitor cell-mediated liver regeneration by suppressing YAP signaling in zebrafish
| PRJNA942269 | ENA
Project description:To investigate mechanisms by which activated β-catenin signaling promotes liver tumor formation and to identify potential therapeutics for these cancers, we generated transgenic zebrafish expressing hepatocyte-specific activated β-catenin (Tg(fabp10a:pt-β-cat) zebrafish. As adults, these animals show increased liver size, decreased survival, and histologic abnormalities similar to human HCC. To further characterize our model, we used microarray analysis to compare gene expression in Tg(fabp10a:pt-β-cat) zebrafish livers to that of non-transgenic control sibling livers. This experiment includes 2 biological replicates. Each replicate represents one Tg(fabp10a:pt-beta-catenin) zebrafish compared to non-transgenic control sibling.
2015-04-30 | E-GEOD-68124 | 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:To investigate mechanisms by which activated β-catenin signaling promotes liver tumor formation and to identify potential therapeutics for these cancers, we generated transgenic zebrafish expressing hepatocyte-specific activated β-catenin (Tg(fabp10a:pt-β-cat) zebrafish. As adults, these animals show increased liver size, decreased survival, and histologic abnormalities similar to human HCC. To further characterize our model, we used microarray analysis to compare gene expression in Tg(fabp10a:pt-β-cat) zebrafish livers to that of non-transgenic control sibling livers.
2015-04-30 | GSE68124 | GEO
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.
2014-09-27 | GSE61817 | GEO
Project description:Background: Studies in mice have shown that PPARα is an important regulator of lipid metabolism in liver and a key transcription factor involved in the adaptive response to fasting. However, much less is known about the role of PPARα in human liver. Here we set out to study the function of PPARα in human liver via analysis of whole genome gene regulation in human liver slices treated with the PPARα agonist Wy14643. Results: Quantitative PCR indicated that PPARα is well expressed in human liver and human liver slices and that the classical PPARα targets PLIN2, VLDLR, ANGPTL4, CPT1A and PDK4 are robustly induced by PPARα activation. Transcriptomics analysis indicated that 617 genes were upregulated and 665 genes were downregulated by PPARα activation (q value<0.05). Many genes induced by PPARα activation were involved in lipid metabolism (ACSL5, AGPAT9, FADS1, SLC27A4), xenobiotic metabolism (POR, ABCC2, CYP3A5) or the unfolded protein response, whereas most of the downregulated genes were involved in immune-related pathways. Among the most highly repressed genes upon PPARα activation were several chemokines (e.g. CXCL9-11, CCL8, CX3CL1, CXCL6), interferon γ-induced genes (e.g. IFITM1, IFIT1, IFIT2, IFIT3) and numerous other immune-related genes (e.g. TLR3, NOS2, and LCN2). Comparative analysis of gene regulation by Wy14643 between human liver slices and primary human hepatocytes showed that down-regulation of gene expression by PPARα is much better captured by liver slices as compared to primary hepatocytes. In particular, PPARα activation markedly suppressed immunity/inflammation-related genes in human liver slices but not in primary hepatocytes. Finally, several putative new target genes of PPARα were identified that were commonly induced by PPARα activation in the two human liver model systems, including TSKU, RHOF, CA12 and VSIG10L. Conclusion: Our manuscript demonstrates the suitability and superiority of human liver slices over primary hepatocytes for studying the functional role of PPARα in human liver. Our data underscore the major role of PPARα in regulation of hepatic lipid and xenobiotic metabolism in human liver and reveal a marked immuno-suppressive/anti-inflammatory effect of PPARα in human liver slices that may be therapeutically relevant for non-alcoholic fatty liver disease.
2015-11-23 | GSE71731 | GEO
Project description:Perfluoroalkyl substances (PFAS) are man-made chemicals with suspected endocrine-disrupting properties. Exposure to perfluorooctanoic acid (PFOA) has been linked to disturbed metabolism via the liver, although the exact mechanism is not clear. Moreover, information on the metabolic effects of the new PFAS alternative GenX is limited. We tested whether low-dose exposure to PFOA and GenX induces metabolic disturbances, including NAFLD, dyslipidemia, and glucose tolerance in mice and studied the involvement of PPARα. To this end, male C57BL/6J wildtype and PPARα−/− mice were given 0.05 or 0.3 mg/kg bw/day PFOA, or 0.3 mg/kg bw/day GenX next to a high-fat diet for 20 weeks. RNA sequencing was performed on liver, next to thorough assesment of metabolic parameters. RNA sequencing revealed that whereas the effects of GenX are entirely dependent on PPARα, effects of PFOA are mostly dependent on PPARα. In the absence of PPARα, the involvement of PXR/CAR becomes more prominent. Exposure to high-dose PFOA in mice decreased body weights and increased liver weights in wildtype and PPARα−/− mice. High-dose but not low-dose PFOA reduced plasma triglycerides and cholesterol, which for triglycerides, showed PPARα dependency. PFOA and GenX increased hepatic triglycerides in a PPARα-dependent manner. Overall, we show that long-term and low-dose exposure to PFOA and GenX disrupts lipid metabolism in mice. Whereas the effects of PFOA are mediated by multiple nuclear receptors, effects of GenX are entirely mediated by PPARα. Our data underscore the potential of PFAS to disrupt metabolism by altering signaling pathways in the liver.
2022-09-02 | GSE212294 | GEO
Project description:In this study, we measured liver miRNA in male B6C3F1 mice exposed to a known chemical activator of the peroxisome proliferator-activated receptor alpha (PPARα) pathway, di(2-ethylhexyl) phthalate (DEHP), for 7 and 28 days at concentrations of 0, 750, 1500, 3000, or 6000 ppm in feed. At the highest dose tested, DEHP altered 61 miRNAs after 7 days and 171 miRNAs after 28 days of exposure, with 48 overlapping miRNAs between timepoints. Analysis of these 48 common miRNAs indicated enrichment in PPARα targets and other pathways related to liver injury and cancer. Four of the 10 miRNAs exhibiting a clear dose trend were linked to PPARα activation: mmu-miRs-125a-5p, -182-5p, -20a-5p, and -378a-3p.
2020-06-30 | GSE144988 | GEO
Project description:We demonstrate that conjugated linoleic acid (CLA), when given to mice as a dietary supplement, induced an enlarged liver and hepatic steatosis. The progression of NAFLD and insulin resistance was reversed by GW6471 a small-molecule antagonist of PPARα. Transcriptional profiling of livers unraveled that genes involved in lipid metabolism core gene programs controlled by PPARα in response to CLA and GW6471.Our findings reveal a novel role of PPARα in the regulation of lipid homeostasis and highlight its druggable nature in NAFLD.
2021-08-27 | GSE159219 | GEO
Project description:Nuclear receptors (NRs) play a crucial role in non-alcoholic fatty liver disease (NAFLD) and have been widely studied(Tran et al. 2018). However, the underlying mechanisms of NR regulation remain largely unclear. Here, we show that miR-20b plays a key role in modulating PPARα, a master regulator of nutrient metabolism and energy homeostasis in the pathogenesis of fatty liver(Wahli et al. 1995; Dongiovanni and Valenti 2013). Using network analysis and RNA-seq to determine the correlation between NRs and microRNA in NAFLD patients, we revealed that miR-20b directly targets PPARα. The expression of miR-20b was remarkably upregulated in free fatty acid (FA)-treated hepatocytes and the livers of both obesity-induced mice and NAFLD patients. Overexpression of miR-20b dramatically increased hepatic lipid accumulation and plasma triglyceride levels. Furthermore, miR-20b significantly reduced fatty acid oxidation and mitochondrial biogenesis by directly targeting PPARα. Fenofibrate, a specific agonist of PPARα, lost its ability to ameliorate hepatic steatosis in miR-20b-introduced mice. Finally, inhibition of miR-20b dramatically increased FA oxidation and uptake, resulting in improved insulin sensitivity and a decrease in NAFLD progression. Taken together, these results demonstrate that the novel miR-20b directly targets PPARα, plays a significant role in hepatic lipid metabolism, and presents an opportunity for the development of novel therapeutics for NAFLD.
2021-03-09 | GSE168484 | GEO