Activating transcription factor 6 is necessary and sufficient for alcoholic fatty liver disease in zebrafish
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ABSTRACT:
ORGANISM(S): Danio rerio
PROVIDER: GSE56498 | GEO | 2014/05/01
SECONDARY ACCESSION(S): PRJNA243510
REPOSITORIES: GEO
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Project description:ATF6 is a key regulator of the unfolded protein response. Through use of zebrafish and cultured cells we demonstrate that ATF6 drives fatty liver disease by interaction with fatty acid synthase (FASN). Total small RNA from livers of 5 dpf larval zebrafish were collected: 2 batches of Tg(fabp10:nls-mCherry) control larvae, 2 batches of ethanol-treated Tg(fabp10:nls-mCherry) larvae, and 1 batch of Tg(fabp10:nAtf6-cherry; cmlc2:GFP). Each batch was purified for preparation of high-throughput sequencing libraries.
2014-05-01 | E-GEOD-56498 | biostudies-arrayexpress
Project description:Fatty liver disease (FLD) is characterized by lipid accumulation in hepatocytes and is accompanied by secretory pathway dysfunction, resulting in induction of the unfolded protein response (UPR). Activating transcription factor 6 (ATF6), one of three main UPR sensors, functions to both promote FLD during acute stress and reduce FLD during chronic stress. There is little mechanistic understanding of how ATF6, or any other UPR factor, regulates hepatic lipid metabolism to cause disease. We addressed this using zebrafish genetics and biochemical analyses and demonstrate that Atf6 is necessary and sufficient for FLD. atf6 transcription is significantly upregulated in the liver of zebrafish with alcoholic FLD and morpholino-mediated atf6 depletion significantly reduced steatosis incidence caused by alcohol. Moreover, overexpression of active, nuclear Atf6 (nAtf6) in hepatocytes caused FLD in the absence of stress. mRNA-Seq and qPCR analyses of livers from five day old nAtf6 transgenic larvae revealed upregulation of genes promoting glyceroneogenesis and fatty acid elongation, including fatty acid synthase (fasn), and nAtf6 overexpression in both zebrafish larvae and human hepatoma cells increased the incorporation of 14C-acetate into lipids. Srebp transcription factors are key regulators of lipogenic enzymes, but reducing Srebp activation by scap morpholino injection neither prevented FLD in nAtf6 transgenics nor synergized with atf6 knockdown to reduce alcohol-induced FLD. In contrast, fasn morpholino injection reduced FLD in nAtf6 transgenic larvae and synergistically interacted with atf6 to reduce alcoholic FLD. Thus, our data demonstrate that Atf6 is required for alcoholic FLD and epistatically interacts with fasn to cause this disease, suggesting triglyceride biogenesis as the mechanism of UPR induced FLD.
| S-EPMC4038464 | biostudies-literature
Project description:Fatty acid synthase is a major enzyme involved in de novo lipogenesis, associated with energy homeostasis, lipid storage and signalling in normal liver cells. The effect of fatty acid synthase knockdown in normal liver cells (THLE 2) using siRNA mediated gene silencing were assesed for global gene deregulations. The deregulated metabolism, cell signalling and cell cycle pathway related gene expressions were analysed. Statistical significance values were also recorded. This expermental analysis clearly points to a important biochemical role for FASN in normal liver cell physiology. Total RNA was extracted from the THLE 2 cells transfected with FASN siRNA at 48h, along with its untransfected control cells. cDNA converted samples were run on microarray platform- Illumina HumanHT-12 V4.0 expression beadchip
2016-06-02 | E-GEOD-82096 | biostudies-arrayexpress
Project description:The fatty acid synthase (FASN) is the major fat synthesizing enzyme. FASN is an indispensable enzyme because mice with genetic deletion of Fasn are not viable. Apart from its physiological function, previous studies indicated that FASN could also exert a pathophysiological role, in the heart, because patients with heart failure showed up-reguation of FASN. To investigate the in vivo function of FASN up-regulation in the heart, we generated mice with myocardium-specific expression of FASN under control of the alpha-MHC promoter. Two different founder lines were generated with high and low FASN over-expression. Microarray gene expression profiling of heart tissue was performed of heart tissue from transgenic mice with high and low FASN expression Microarray gene expression profiling was performed with heart tissue isolated from three study groups: (i) Transgenic mice with high cardiac FASN expression, (ii) transgenic mice with low cardiac FASN expression, and (iii) B6 control mice.
2013-07-31 | E-GEOD-49351 | biostudies-arrayexpress
Project description:Metabolic diseases are closely linked to aberrant synthesis of endogenous fatty acids in the liver, called de novo lipogenesis (DNL), which is mediated by the enzyme fatty acid synthase (FASN). The composition of complex lipids consists of saturated or monosaturated fatty acids, which can be endogenously produced, and polyunsaturated fatty acids (PUFA), which are strictly dietary. Compositional differences between individuals are insufficiently understood and may influence the onset and progression of metabolic and cardiovascular diseases. Here we show that DNL critically determines the use of dietary PUFA. A patient with a hypofunctional heterozygous de novo Arg2177Cys variant in FASN exhibited an elevated composition of PUFA, which was phenocopied by pharmacological inhibition of FASN with TVB-2640 in patients with nonalcoholic steatohepatitis (NASH). In mice, the incorporation rate of supplemented omega-3 PUFA during an obesogenic diet was increased by genetic or pharmacologic reduction of DNL. Mechanistically, we show that the FASN variant exhibited a cysteine-dependent, non-enzymatic acetylation of FASN, which resulted in hyperubiquitinylation and decreased protein stability. Our study further reveals that PUFA storage is an active, enzymatic process controlled by FASN, diacylglycerol O-acyltransferase 2 (DGAT2) and MFSD2A, a membrane-transport protein, and that combining FASN inhibition and PUFA supplementation exerts additive beneficial metabolic effects. These findings provide evidence that the success of PUFA supplementation may depend on the rate of endogenous DNL and that combined PUFA supplementation and FASN inhibition may be a promising approach targeting metabolic disease.
2023-12-19 | PXD045908 | Pride
Project description:In the central nervous system, oligodendrocytes encase axons with myelin, a highly organized multilayered membrane structure. Myelin allows the rapid propagation of action potentials along the axons, while also supporting their mantainance metabolically. Fatty acids are basic building blocks for both glyco- and phospholipids, key constituents of cell membranes. Moreover, fatty acids can modify proteins via palmitoylation and activate transcriptional networks, e.g. through the PPARs transcription factors. Due to the high demand of membrane oligodendrocytes face to produce myelin, we hypothesized that they strongly rely upon fatty acid synthesis rather than mostly on their intake from the dietary pool. We tested this hypothesis by deleting the enzyme Fatty Acid Synthase specifically from neonatal oligodendrocyte progenitor cells, in vivo in C57Bl/6 olig2Cre FASN floxed mice. We addressed the consequences of this depletion on oligodendrocytes differentation and myelination potential in the central nervous system. In particular, we analyzed by RNA-seq how lack of FASN affected the transcriptome of optic nerves dissected from P14 mutant (olig2Cre FASN lox/lox) versus control (FASN lox/lox) mice.
2019-05-03 | GSE112725 | GEO
Project description:SK-UT-1 uterine leiomyosarcomas (Ut-LMS) cells were transduced with a fatty acid synthase (FASN)-containing retroviral vector to recapitulate the “lipogenic phenotype of cancer.” Consistent with this model, forced expression of FASN enhanced SK-UT-1 proliferation, migration, and cellular motion. Further investigation showed FASN promotes trimethylation of H3K9 (H3K9me3) and acetylation of H3K27 (H3K27ac) in SK-UT-1 cells. In contrast, siRNA targeting of FASN in high endogenous FASN expressing SK-LMS-1 Ut-LMS cells inhibits trimethylation of H3K9 and acetylation of H3K27. Palmitate, the predominant fatty acid product of FASN, increased H3K9me3, H3K27ac and H3K27me3 detection in SK-UT-1 cells. FASN promoted histone 3 methylation and acetylation through alteration of histone 3-modifying enzymatic activities (HDAC, HDM, HMT and HAT).ChIP-seq in SK-UT-1-FASN cells with anti-H3K9me3 antibody identified regions of enriched binding compared to vector-only cells. One differentially-enriched gene, CRISP1, was investigated further by ChIP-PCR. The transcriptionally repressive function of H3K9me3 was confirmed in CRISP1. Our results provide mechanistic insight into the pathobiology of the “lipogenic phenotype of cancer.” Here, FASN reprograms the Ut-LMS epigenome through chromatin remodeling to promote the “malignant phenotype.”
2017-06-14 | GSE98557 | GEO
Project description:Mammalian fatty acid synthase (FASN) is a lipogenic enzyme that catalyzes the formation of the long chain saturated fatty acid palmitate from acetyl and malonyl CoA in the presence of NADPH. Mammalian cells acquire fatty acids through dietary sources or through FASN. Although most mammalian cells express FASN at low levels, it is upregulated in cancers and during replication of many viruses. The precise role of FASN in disease pathogenesis is poorly understood, and whether de novo fatty acid synthesis contributes to host or viral protein acylation has been traditionally difficult to study. We describe a cell permeable, click-chemistry compatible alkynyl-acetate analog (5-Hexynoic acid, or "Alk-4") that functions as a reporter of FASN-dependent protein acylation. Alk-4 metabolic labeling enabled biotin-based purification and identification of more than 200 FASN-dependent acylated cellular proteins. Alk-4 also labeled the palmitoylated host protein IFITM3 (Interferon inducible transmembrane protein-3), a restriction factor for Influenza, and the myristoylated HIV-1 MA (Matrix) protein. Thus, Alk-4 is a useful bioorthogonal tool to selectively probe FASN-mediated protein acylation in normal and diseased states.
2022-02-15 | PXD028244 | Pride
Project description:The fatty acid synthase (FASN) is the major fat synthesizing enzyme. FASN is an indispensable enzyme because mice with genetic deletion of Fasn are not viable. Apart from its physiological function, previous studies indicated that FASN could also exert a pathophysiological role, in the heart, because patients with heart failure showed up-reguation of FASN. To investigate the in vivo function of FASN up-regulation in the heart, we generated mice with myocardium-specific expression of FASN under control of the alpha-MHC promoter. Two different founder lines were generated with high and low FASN over-expression. Microarray gene expression profiling of heart tissue was performed of heart tissue from transgenic mice with high and low FASN expression
2013-07-31 | GSE49351 | GEO
Project description:Cells harbor two systems for the synthesis of fatty acids, one in the cytoplasm (FASN or fatty acid synthase) and one in the mitochondria (mtFAS). In contrast to FASN, mtFAS is poorly characterized, with the major product(s), metabolic roles, and cellular function(s) essentially unknown. Here we show that hypomorphic mtFAS mutants display a profound loss of electron transport chain (ETC) complexes and exhibit compensatory reductive carboxylation. This effect on ETC complexes is independent of the synthesis of lipoic acid, the best characterized function of mtFAS, as mutants lacking lipoic acid synthesis have an intact ETC. Finally, mtFAS impairment blocks the differentiation of skeletal myoblasts in vitro. These data suggest that ETC activity in mammals is profoundly controlled by mtFAS function, thereby connecting anabolic fatty acid synthesis with the oxidation of carbon fuels.
2020-08-17 | GSE148617 | GEO