Author Correction: mTORC2-AKT signaling to ATP-citrate lyase drives brown adipogenesis and de novo lipogenesis

Abstract mTORC2 phosphorylates AKT in a hydrophobic motif site that is a biomarker of insulin sensitivity. In brown adipocytes, mTORC2 regulates glucose and lipid metabolism, however the mechanism has been unclear because downstream AKT signaling appears unaffected by mTORC2 loss. Here, by applying immunoblotting, targeted phosphoproteomics and metabolite profiling, we identify ATP-citrate lyase (ACLY) as a distinctly mTORC2-sensitive AKT substrate in brown preadipocytes. mTORC2 appears dispensable for most other AKT actions examined, indicating a previously unappreciated selectivity in mTORC2-AKT signaling. Rescue experiments suggest brown preadipocytes require the mTORC2/AKT/ACLY pathway to induce PPAR-gamma and establish the epigenetic landscape during differentiation. Evidence in mature brown adipocytes also suggests mTORC2 acts through ACLY to increase carbohydrate response element binding protein (ChREBP) activity, histone acetylation, and gluco-lipogenic gene expression. Substrate utilization studies additionally implicate mTORC2 in promoting acetyl-CoA synthesis from acetate through acetyl-CoA synthetase 2 (ACSS2). These data suggest that a principal mTORC2 action is controlling nuclear-cytoplasmic acetyl-CoA synthesis.

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In Steatotic Cells, ATP-Citrate Lyase mRNA Is Efficiently Translated through a Cap-Independent Mechanism, Contributing to the Stimulation of De Novo Lipogenesis

International Journal of Molecular Sciences ◽

10.3390/ijms21041206 ◽

2020 ◽

Vol 21 (4) ◽

pp. 1206 ◽

Cited By ~ 1

Author(s):

Luisa Siculella ◽

Laura Giannotti ◽

Mariangela Testini ◽

Gabriele V. Gnoni ◽

Fabrizio Damiano

Keyword(s):

Lipid Accumulation ◽

De Novo ◽

Cell Model ◽

Mrna Translation ◽

De Novo Lipogenesis ◽

Atp Citrate Lyase ◽

Entry Site ◽

Alcoholic Fatty Liver ◽

Citrate Lyase ◽

Independent Mechanism

Non-alcoholic fatty liver disease (NAFLD) is a chronic disease in which excessive amount of lipids is accumulated as droplets in hepatocytes. Recently, cumulative evidences suggested that a sustained de novo lipogenesis can play an important role in NAFLD. Dysregulated expression of lipogenic genes, including ATP-citrate lyase (ACLY), has been found in liver diseases associated with lipid accumulation. ACLY is a ubiquitous cytosolic enzyme positioned at the intersection of nutrients catabolism and cholesterol and fatty acid biosyntheses. In the present study, the molecular mechanism of ACLY expression in a cell model of steatosis has been reported. We identified an internal ribosome entry site (IRES) in the 5′ untranslated region of the ACLY mRNA, that can support an efficient mRNA translation through a Cap-independent mechanism. In steatotic HepG2 cells, ACLY expression was up-regulated through IRES-mediated translation. Since it has been demonstrated that lipid accumulation in cells induces endoplasmic reticulum (ER) stress, the involvement of this cellular pathway in the translational regulation of ACLY has been also evaluated. Our results showed that ACLY expression was increased in ER-stressed cells, through IRES-mediated translation of ACLY mRNA. A potential role of the Cap-independent translation of ACLY in NAFLD has been discussed.

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mTOR complex-2 stimulates acetyl-CoA and de novo lipogenesis through ATP citrate lyase in HER2/PIK3CA-hyperactive breast cancer

Oncotarget ◽

10.18632/oncotarget.8279 ◽

2016 ◽

Vol 7 (18) ◽

pp. 25224-25240 ◽

Cited By ~ 15

Author(s):

Yaqing Chen ◽

Jianchang Qian ◽

Qun He ◽

Hui Zhao ◽

Lourdes Toral-Barza ◽

...

Keyword(s):

Breast Cancer ◽

De Novo ◽

De Novo Lipogenesis ◽

Atp Citrate Lyase ◽

Acetyl Coa ◽

Citrate Lyase

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Abstract B64: Development of a novel strategy to overcome drug resistance by targeting ATP citrate lyase and de novo lipogenesis in colorectal cancer cells

Clinical Cancer Research ◽

10.1158/1078-0432.mechres-b64 ◽

2012 ◽

Vol 18 (10 Supplement) ◽

pp. B64-B64

Author(s):

Yunfei Zhou ◽

Federico Tozzi ◽

Ling Xia ◽

Fan Fan ◽

Jia Lu ◽

...

Keyword(s):

Colorectal Cancer ◽

Drug Resistance ◽

Cancer Cells ◽

De Novo ◽

De Novo Lipogenesis ◽

Atp Citrate Lyase ◽

Citrate Lyase ◽

Colorectal Cancer Cells ◽

Novel Strategy

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Abstract 17608: Identification of a Tissue-specific Very Long-chain Acyl-CoA Synthetase Involved in the Inhibition of ATP-Citrate Lyase (ACL) by ETC-1002: A Novel Mechanism for Cholesterol Biosynthesis Inhibition in the Liver

Circulation ◽

10.1161/circ.132.suppl_3.17608 ◽

2015 ◽

Vol 132 (suppl_3) ◽

Author(s):

Stephen L Pinkosky ◽

Roger S Newton ◽

Carolyn M Birch ◽

Sergey Filippov ◽

Pieter H Groot ◽

...

Keyword(s):

Skeletal Muscle ◽

Human Skeletal Muscle ◽

Cholesterol Synthesis ◽

De Novo ◽

Cholesterol Biosynthesis ◽

Human Hepatocytes ◽

Atp Citrate Lyase ◽

Tissue Specific ◽

Citrate Lyase ◽

Regulatory Link

ETC-1002 is a first-in-class oral small molecule that significantly lowers levels of low- density lipoprotein-cholesterol (LDL-C) by 30-40% in hypercholesterolemic patients with reduced potential for muscle-related adverse events. Our previous investigations into the mechanism of action demonstrated a requirement for acyl-CoA synthetase- (ACS) dependent coenzyme A (CoA) activation of ETC-1002 (ETC-1002-CoA) to inhibit its molecular target, ATP-citrate lyase (ACL), an enzyme upstream of HMG-CoA reductase in the cholesterol biosynthesis pathway. In the present study, we have elucidated a mechanistic basis for tissue-specific inhibition of ACL by providing evidence that ACSVL1 is the ACS isoform that catalyzes the CoA activation of ETC-1002. Genetic silencing of ACSVL1 in McArdle cells prevented the CoA activation of ETC-1002 and consequently its inhibition of de novo cholesterol synthesis. We demonstrate that ACSVL1 is highly expressed in primary human hepatocytes and human liver microsomes. Furthermore, we establish a statin-like regulatory link between ACL activity and cholesterol metabolism by showing that ACL siRNA silencing or pharmacological inhibition by ETC-1002-CoA, leads to increased LDLR expression and activity. Using primary human hepatocytes, we demonstrate the concentration-dependent inhibition of cholesterol synthesis by ETC-1002, an associated increase in mRNA expression of the sterol responsive genes srebp2, hmgr, pcsk9, and ldlr mRNA, and increased LDLR activity. In addition, we demonstrate that ACSVL1 is not expressed in L6 myotubes, primary human skeletal muscle cells, or human skeletal muscle microsomes. Unlike statins, ETC-1002 did not inhibit the de novo synthesis of sterols in skeletal muscle cell cultures, nor promote caspase 3/7 activation. Therefore, by establishing a regulatory link between ACL inhibition and LDLR up-regulation, and by identifying ACSVL1 as the ACS isoform that catalyzes the CoA activation of ETC-1002, we provide evidence for the tissue-specific inhibition of ACL by ETC-1002-CoA that results in LDL-C-lowering without activity in skeletal muscle or associated side effects.

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Analysis of lines of mice selected for fat content. 2. Correlated responses in the activities of enzymes involved in lipogenesis

Genetics Research ◽

10.1017/s0016672300025192 ◽

1990 ◽

Vol 55 (1) ◽

pp. 55-61 ◽

Cited By ~ 23

Author(s):

Ian M. Hastings ◽

William G. Hill

Keyword(s):

De Novo ◽

Fatty Acid Synthetase ◽

Fat Content ◽

Acetyl Coa Carboxylase ◽

Correlated Responses ◽

Atp Citrate Lyase ◽

Citrate Lyase ◽

Obesity In Mice ◽

Made In

SummaryEstimates of the activities (Vmax) of six enzymes involved in de novo fat synthesis were made in replicated lines of mice differing in fat content. These lines had been selected high and low for 20 generations with three replicates each of Fat, Control and Lean lines and for a further eight generations high and low as an unreplicated line. The activities of ATP-citrate lyase (ACL), acetyl-CoA carboxylase (ACC), fatty acid synthetase (FAS), cytoplasmic malate dehydrogenase (MDH), malic enzyme (ME) and pyruvate kinase (PK) were determined in vitro in both liver and gonadal fatpad tissues taken at ages five and ten weeks. The activities of ACL, ACC, FAS and ME were significantly higher in the Fat than the Lean lines, and the differences were more pronounced at the earlier age and in the gonadal fatpad where activities in the Fat lines were higher by factors of 3·5, 2·4, 2·5 and 3·5 respectively. The activity of PK was unchanged in each tissue. MDH activity was significantly lower in adipose tissue in the Fat lines than the Lean lines at age ten weeks but not at age five weeks or in liver tissue. Results from replicates indicated that random genetic drift affected enzyme activities but nevertheless significant changes in activity were associated with the direction of selection. The changes in enzyme activity reported here are similar to those known to be associated with major mutations causing obesity in mice.

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De novo acetate production is coupled to central carbon metabolism in mammals

10.1101/259523 ◽

2018 ◽

Author(s):

Xiaojing Liu ◽

Daniel E. Cooper ◽

Ahmad A. Cluntun ◽

Marc O. Warmoes ◽

Steven Zhao ◽

...

Keyword(s):

Carbon Metabolism ◽

De Novo ◽

Waste Product ◽

Pyruvate Decarboxylase ◽

Central Carbon Metabolism ◽

Overflow Metabolism ◽

Acetate Production ◽

Atp Citrate Lyase ◽

Citrate Lyase ◽

Central Carbon

AbstractIn cases of nutritional excess, there is incomplete catabolism of a nutritional source and secretion of a waste product (overflow metabolism), such as the conversion of glucose to lactate (the Warburg Effect) in tumors. Here we report that excess glucose metabolism generates acetate, a key nutrient whose source has been unclear. Conversion of pyruvate, the product of glycolysis, to acetate occurs through two mechanisms: 1) coupling to reactive oxygen species (ROS), and 2) a neomorphic enzyme activity from keto acid dehydrogenases that enable it to function as a pyruvate decarboxylase. Furthermore, we demonstrate that glucose-derived acetate is sufficient to maintain acetyl-coenzyme A (Ac-CoA) pools and cell proliferation in certain limited metabolic environments such as during mitochondrial dysfunction or ATP citrate lyase (ACLY) deficiency. Thus, de novo acetate production is coupled to the activity of central carbon metabolism providing possible regulatory mechanisms and links to pathophysiology.

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The role of ATP citrate-lyase in the metabolic regulation of plasma lipids

Biochemical Journal ◽

10.1042/bj3340113 ◽

1998 ◽

Vol 334 (1) ◽

pp. 113-119 ◽

Cited By ~ 60

Author(s):

Nigel J. PEARCE ◽

John W. YATES ◽

Theo A. BERKHOUT ◽

Brian JACKSON ◽

David TEW ◽

...

Keyword(s):

Plasma Lipids ◽

De Novo ◽

Plasma Cholesterol ◽

Low Density Lipoprotein ◽

Lipid Synthesis ◽

Density Lipoprotein ◽

Acid Synthesis ◽

Atp Citrate Lyase ◽

Cholesterol Levels ◽

Citrate Lyase

ATP citrate (pro-S)-lyase (EC 4.1.3.8), a cytosolic enzyme that generates acetyl-CoA for cholesterol and fatty acid synthesis de novo, is a potential target for hypolipidaemic intervention. Here we describe the biological effects of the inhibition of ATP citrate-lyase on lipid metabolism in Hep G2 cells, and plasma lipids in rats and dogs, by using SB-204990, the cell-penetrant γ-lactone prodrug of the potent ATP citrate-lyase inhibitor SB-201076 (Ki = 1 µM). Consistent with an important role of ATP citrate-lyase in the supply of acetyl-CoA units for lipid synthesis de novo, SB-204990 inhibited cholesterol synthesis and fatty acid synthesis in Hep G2 cells (dose-related inhibition of up to 91% and 82% respectively) and rats (76% and 39% respectively). SB-204990, when administered orally to rats, was absorbed into the systemic circulation; pharmacologically relevant concentrations of SB-201076 were recovered in the liver. When administered in the diet (0.05–0.25%, w/w) for 1 week, SB-204990 caused a dose-related decrease in plasma cholesterol (by up to 46%) and triglyceride levels (by up to 80%) in rats. This hypolipidaemic effect could be explained, at least in part, by a decrease (up to 48%) in hepatic very-low-density lipoprotein (VLDL) production as measured by the accumulation of VLDL in plasma after injection of Triton WR-1339. SB-204990 (25 mg/kg per day) also decreased plasma cholesterol levels (by up to 23%) and triglyceride levels (by up to 38%) in the dog, preferentially decreasing low-density lipoprotein compared with high-density lipoprotein cholesterol levels. Overall these results are consistent with the concept that ATP citrate-lyase is an important enzyme in controlling substrate supply for lipid synthesis de novo and a potential enzyme target for hypolipidaemic intervention.

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Exploring the Role of ATP-Citrate Lyase in the Immune System

Frontiers in Immunology ◽

10.3389/fimmu.2021.632526 ◽

2021 ◽

Vol 12 ◽

Author(s):

Monica Dominguez ◽

Bernhard Brüne ◽

Dmitry Namgaladze

Keyword(s):

Immune System ◽

Immune Responses ◽

Histone Acetylation ◽

Epigenetic Regulation ◽

De Novo ◽

Regulation Of Gene Expression ◽

Atp Citrate Lyase ◽

Acetyl Coa ◽

Citrate Lyase

Studies over the past decade have revealed that metabolism profoundly influences immune responses. In particular, metabolism causes epigenetic regulation of gene expression, as a growing number of metabolic intermediates are substrates for histone post-translational modifications altering chromatin structure. One of these substrates is acetyl-coenzyme A (CoA), which donates an acetyl group for histone acetylation. Cytosolic acetyl-CoA is also a critical substrate for de novo synthesis of fatty acids and sterols necessary for rapid cellular growth. One of the main enzymes catalyzing cytosolic acetyl-CoA formation is ATP-citrate lyase (ACLY). In addition to its classical function in the provision of acetyl-CoA for de novo lipogenesis, ACLY contributes to epigenetic regulation through histone acetylation, which is increasingly appreciated. In this review we explore the current knowledge of ACLY and acetyl-CoA in mediating innate and adaptive immune responses. We focus on the role of ACLY in supporting de novo lipogenesis in immune cells as well as on its impact on epigenetic alterations. Moreover, we summarize alternative sources of acetyl-CoA and their contribution to metabolic and epigenetic regulation in cells of the immune system.

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