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Dixon ED, Claudel T, Nardo AD, Riva A, Fuchs C, Mlitz V, Busslinger G, Schnarnagl H, Stojakovic T, Senéca J, Hinteregger H, Grabner GF, Kratky D, Verkade H, Zimmermann R, Haemmerle G, Trauner M. Inhibition of ATGL alleviates MASH via impaired PPARα signalling that favours hydrophilic bile acid composition in mice. J Hepatol 2024:S0168-8278(24)02577-7. [PMID: 39357546 DOI: 10.1016/j.jhep.2024.09.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 09/19/2024] [Accepted: 09/20/2024] [Indexed: 10/04/2024]
Abstract
BACKGROUND AND AIMS Adipose triglyceride lipase (ATGL) is an attractive therapeutic target in insulin resistance and metabolic dysfunction-associated steatotic liver disease (MASLD). This study investigated the effects of pharmacological ATGL inhibition on the development of metabolic dysfunction-associated steatohepatitis (MASH) and fibrosis in mice. METHODS Streptozotocin-injected male mice were fed an HFD to induce MASH. Mice receiving the ATGL inhibitor, Atglistatin (ATGLi), were compared to controls using liver histology, lipidomics, metabolomics, 16s rRNA, and RNA sequencing. Human ileal organoids, HepG2 cells, and Caco2 cells treated with the human ATGL inhibitor NG-497, HepG2 ATGL knockdown cells, gel-shift, and luciferase assays were analysed for mechanistic insights. We validated its benefits on steatohepatitis and fibrosis in a low-methionine choline-deficient mouse model. RESULTS ATGLi improved serum liver enzymes, hepatic lipid content, and histological liver injury. Mechanistically, ATGLi attenuated PPARα signalling, favouring hydrophilic bile acid (BA) synthesis with increased Cyp7a1, Cyp27a1, Cyp2c70, and reduced Cyp8b1 expression. Additionally, reduced intestinal Cd36 and Abca1, along with increased Abcg5 expression, were consistent with reduced levels of hepatic TAG-species containing PUFAs like linoleic acids as well as reduced cholesterol levels in the liver and plasma. Similar changes in gene expression associated with PPARα signaling and intestinal lipid transport were observed in ileal organoids treated with NG-497. Furthermore, HepG2 ATGL knockdown cells revealed reduced expression of PPARα target genes and upregulation of genes involved in hydrophilic BA synthesis, consistent with reduced PPARα binding and luciferase activity in the presence of the ATGL inhibitors. CONCLUSIONS Inhibition of ATGL attenuates PPARα signalling, translating into hydrophilic BAs, interfering with dietary lipid absorption, and improving metabolic disturbances. The validation with NG-497 opens a new therapeutic perspective for MASLD. IMPACT AND IMPLICATIONS The global prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is a crucial public health concern. Since adherence to behavioural interventions is limited, pharmacological strategies are necessary, as highlighted by the recent FDA approval of resmetirom. However, since our current mechanistic understanding and pathophysiology-oriented therapeutic options for MASLD are still limited, novel mechanistic insights are urgently needed. Our present work uncovers that pharmacological inhibition of ATGL, the key enzyme in lipid hydrolysis using Atglistatin (ATGLi), improves metabolic dysfunction-associated steatohepatitis (MASH), fibrosis, and associated key features of metabolic dysfunction in a mouse model of MASH and MCD-induced liver fibrosis. Mechanistically, we demonstrated that attenuation of PPARα signalling in the liver and gut favours hydrophilic bile acid composition, ultimately interfering with dietary lipid absorption. One of the drawbacks of ATGLi is its lack of efficacy against human ATGL, thus limiting its clinical applicability. Against this backdrop, we could show that ATGL inhibition using the human inhibitor NG-497 in human primary ileum-derived organoids, Caco2 cells, and HepG2 cells translated into therapeutic mechanisms similar to ATGLi. Collectively, these findings open a new avenue for MASLD treatment development by inhibiting human ATGL activity.
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Affiliation(s)
- Emmanuel Dauda Dixon
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Medical University of Vienna
| | - Thierry Claudel
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Medical University of Vienna
| | - Alexander Daniel Nardo
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Medical University of Vienna
| | - Alessandra Riva
- Chair of Nutrition and Immunology, School of Life Sciences, Technische Universität München, Freising-Weihenstephan, Germany
| | - Claudia Fuchs
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Medical University of Vienna
| | - Veronika Mlitz
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Medical University of Vienna
| | - Georg Busslinger
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Medical University of Vienna; Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Hubert Schnarnagl
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Austria
| | - Tatjana Stojakovic
- Institute of Medical and Chemical Laboratory Diagnostics, University Hospital Graz, Austria
| | - Joana Senéca
- Joint Microbiome Facility of the Medical University of Vienna and the University of Vienna, Vienna, Austria; Department of Microbiology and Ecosystem Science, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Helga Hinteregger
- Division of Molecular Biology and Biochemistry, Medical University of Graz, Austria
| | - Gernot F Grabner
- Division of Molecular Biology and Biochemistry, Medical University of Graz, Austria
| | - Dagmar Kratky
- Division of Molecular Biology and Biochemistry, Medical University of Graz, Austria
| | - Henkjan Verkade
- Department of Paediatrics, University Medical Centre Groningen, Groningen, Netherlands
| | - Robert Zimmermann
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Guenter Haemmerle
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Michael Trauner
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Medical University of Vienna.
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Yang H, Suh DH, Jung ES, Lee Y, Liu KH, Do IG, Lee CH, Park CY. Ezetimibe, Niemann-Pick C1 like 1 inhibitor, modulates hepatic phospholipid metabolism to alleviate fat accumulation. Front Pharmacol 2024; 15:1406493. [PMID: 38953111 PMCID: PMC11215075 DOI: 10.3389/fphar.2024.1406493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Accepted: 05/13/2024] [Indexed: 07/03/2024] Open
Abstract
Background Ezetimibe, which lowers cholesterol by blocking the intestinal cholesterol transporter Niemann-Pick C1 like 1, is reported to reduce hepatic steatosis in humans and animals. Here, we demonstrate the changes in hepatic metabolites and lipids and explain the underlying mechanism of ezetimibe in hepatic steatosis. Methods We fed Otsuka Long-Evans Tokushima Fatty (OLETF) rats a high-fat diet (60 kcal % fat) with or vehicle (control) or ezetimibe (10 mg kg-1) via stomach gavage for 12 weeks and performed comprehensive metabolomic and lipidomic profiling of liver tissue. We used rat liver tissues, HepG2 hepatoma cell lines, and siRNA to explore the underlying mechanism. Results In OLETF rats on a high-fat diet, ezetimibe showed improvements in metabolic parameters and reduction in hepatic fat accumulation. The comprehensive metabolomic and lipidomic profiling revealed significant changes in phospholipids, particularly phosphatidylcholines (PC), and alterations in the fatty acyl-chain composition in hepatic PCs. Further analyses involving gene expression and triglyceride assessments in rat liver tissues, HepG2 hepatoma cell lines, and siRNA experiments unveiled that ezetimibe's mechanism involves the upregulation of key phospholipid biosynthesis genes, CTP:phosphocholine cytidylyltransferase alpha and phosphatidylethanolamine N-methyl-transferase, and the phospholipid remodeling gene lysophosphatidylcholine acyltransferase 3. Conclusion This study demonstrate that ezetimibe improves metabolic parameters and reduces hepatic fat accumulation by influencing the composition and levels of phospholipids, specifically phosphatidylcholines, and by upregulating genes related to phospholipid biosynthesis and remodeling. These findings provide valuable insights into the molecular pathways through which ezetimibe mitigates hepatic fat accumulation, emphasizing the role of phospholipid metabolism.
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Affiliation(s)
- Hyekyung Yang
- Medical Research Institute, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Dong Ho Suh
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, Republic of Korea
| | - Eun Sung Jung
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, Republic of Korea
| | - Yoonjin Lee
- Medical Research Institute, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Kwang-Hyeon Liu
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu, Republic of Korea
| | - In-Gu Do
- Department of Pathology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Choong Hwan Lee
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, Republic of Korea
| | - Cheol-Young Park
- Medical Research Institute, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
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Li J, Xin Y, Li J, Chen H, Li H. Phosphatidylethanolamine N-methyltransferase: from Functions to Diseases. Aging Dis 2023; 14:879-891. [PMID: 37191416 PMCID: PMC10187709 DOI: 10.14336/ad.2022.1025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 10/25/2022] [Indexed: 11/18/2022] Open
Abstract
Locating on endoplasmic reticulum and mitochondria associated membrane, Phosphatidylethanolamine N-methyltransferase (PEMT), catalyzes phosphatidylethanolamine methylation to phosphatidylcholine. As the only endogenous pathway for choline biosynthesis in mammals, the dysregulation of PEMT can lead to imbalance of phospholipid metabolism. Dysregulation of phospholipid metabolism in the liver or heart can lead to deposition of toxic lipid species that adversely result in dysfunction of hepatocyte/cardiomyocyte. Studies have shown that PEMT-/- mice increased susceptibility of diet-induced fatty liver and steatohepatitis. However, knockout of PEMT protects against diet-induced atherosclerosis, diet-induced obesity, and insulin resistance. Thus, novel insights to the function of PEMT in various organs should be summarized. Here, we reviewed the structural and functional properties of PEMT, highlighting its role in the pathogenesis of obesity, liver diseases, cardiovascular diseases, and other conditions.
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Affiliation(s)
- Jiayu Li
- Department of Cardiology, Cardiovascular Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.
| | - Yanguo Xin
- Department of Cardiology, Cardiovascular Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.
| | - Jingye Li
- Department of Cardiology, Cardiovascular Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.
| | - Hui Chen
- Department of Cardiology, Cardiovascular Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.
| | - Hongwei Li
- Department of Cardiology, Cardiovascular Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.
- Beijing Key Laboratory of Metabolic Disorder Related Cardiovascular Disease, Beijing, China.
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Wang X, Luo J, Lu Z, Fang S, Sun M, Luo W, Shen J, Liu A, Ye H. Therapeutic effect of fenofibrate for non-alcoholic steatohepatitis in mouse models is dependent on regime design. Front Pharmacol 2023; 14:1190458. [PMID: 37251331 PMCID: PMC10213340 DOI: 10.3389/fphar.2023.1190458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 05/03/2023] [Indexed: 05/31/2023] Open
Abstract
Background: Non-alcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver diseases. In most cases, NAFLD progresses from benign steatosis to steatohepatitis (NASH), and then to cirrhosis. No treatment is currently approved for NAFLD/NASH in the clinic. Fenofibrate (FENO) has been clinically used to treat dyslipidemia for more than a half century, but its effects on NASH are not established. FENO's half-life is quite different between rodent and human. The aim of this study was to investigate the potential of pharmacokinetic-based FENO regime for NASH treatment and the underlying mechanisms. Methods: Two typical mouse NASH models, methionine-choline deficient (MCD) diet-fed mice and choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD)-fed mice, were used. MCD model was designed as therapeutic evaluation in experiment 1 and CDAHFD model was designed as preventive in experiment 2. Three doses of FENO (5, 25, 125 mg/kg), two times a day (BID), were administered to the above models. Serum markers of liver injury, cholestasis, and the histology of liver tissues were investigated. Normal mice were used as a model in experiment 3 for toxicity evaluation, Quantitative-PCR and Western Blot assays were used to investigate the inflammatory responses, bile acid synthesis as well as lipid catabolism. Results: Mice on the MCD and CDAHFD diets developed steatohepatitis as expected. Treatment with FENO (25 mg/kg·BID) significantly decreased hepatic steatosis, inflammation and fibrosis in both therapeutic and preventive models. In the MCD model, the therapeutic action of FENO (25 mg/kg·BID) and 125 mg/kg·BID on histopathology and the expression of inflammatory cytokines were comparable. In reducing macrophage infiltration and bile acid load, FENO (25 mg/kg·BID) was superior to 125 mg/kg·BID. In all the aspects mentioned above, FENO (25 mg/kg·BID) was the best among the 3 doses in the CDAHFD model. In a third experiment, the effects of FENO (25 mg/kg·BID) and 125 mg/kg·BID on lipid catabolism were comparable, but 125 mg/kg·BID increased the expression of inflammatory factors and bile acid load. In both models, FENO (5 mg/kg·BID) showed little effect in hepatic steatosis and inflammation, neither the adverse effects. FENO (125 mg/kg·BID) aggravated liver inflammation, increased bile acid synthesis, and promoted the potential of liver proliferation. In toxicity risk assay, FENO (25 mg/kg·BID) treatment showed low potential to trigger bile acid synthesis, inflammation and hepatocyte proliferation. Conclusion: A new regime, FENO (25 mg/kg·BID) is potentially a therapeutic strategy for the NASH treatment. Translational medicine is warranted to prove its effectiveness in the clinic.
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Affiliation(s)
- Xinxue Wang
- Department of Gastroenterology, The Affiliated Lihuili Hospital of Ningbo University, Ningbo, China
| | - Jia Luo
- Zhejiang Key Laboratory of Pathophysiology, Department of Pharmacology, Health Science Center, Ningbo University, Ningbo, China
| | - Zhuoheng Lu
- Zhejiang Key Laboratory of Pathophysiology, Department of Pharmacology, Health Science Center, Ningbo University, Ningbo, China
| | - Shenzhe Fang
- Department of Gastroenterology, The Affiliated Lihuili Hospital of Ningbo University, Ningbo, China
| | - Mengxia Sun
- Zhejiang Key Laboratory of Pathophysiology, Department of Pharmacology, Health Science Center, Ningbo University, Ningbo, China
| | - Wenjing Luo
- Department of Gastroenterology, The Affiliated Lihuili Hospital of Ningbo University, Ningbo, China
| | - Jianwei Shen
- Department of Gastroenterology, The Affiliated Lihuili Hospital of Ningbo University, Ningbo, China
| | - Aiming Liu
- Zhejiang Key Laboratory of Pathophysiology, Department of Pharmacology, Health Science Center, Ningbo University, Ningbo, China
| | - Hua Ye
- Department of Gastroenterology, The Affiliated Lihuili Hospital of Ningbo University, Ningbo, China
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Molecular mechanisms of metabolic associated fatty liver disease (MAFLD): functional analysis of lipid metabolism pathways. Clin Sci (Lond) 2022; 136:1347-1366. [PMID: 36148775 PMCID: PMC9508552 DOI: 10.1042/cs20220572] [Citation(s) in RCA: 84] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 09/12/2022] [Accepted: 09/14/2022] [Indexed: 01/30/2023]
Abstract
The metabolic-associated fatty liver disease (MAFLD) is a condition of fat accumulation in the liver in combination with metabolic dysfunction in the form of overweight or obesity and insulin resistance. It is also associated with an increased cardiovascular disease risk, including hypertension and atherosclerosis. Hepatic lipid metabolism is regulated by a combination of the uptake and export of fatty acids, de novo lipogenesis, and fat utilization by β-oxidation. When the balance between these pathways is altered, hepatic lipid accumulation commences, and long-term activation of inflammatory and fibrotic pathways can progress to worsen the liver disease. This review discusses the details of the molecular mechanisms regulating hepatic lipids and the emerging therapies targeting these pathways as potential future treatments for MAFLD.
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Liver Protective Effect of Fenofibrate in NASH/NAFLD Animal Models. PPAR Res 2022; 2022:5805398. [PMID: 35754743 PMCID: PMC9232374 DOI: 10.1155/2022/5805398] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/19/2022] [Accepted: 06/02/2022] [Indexed: 12/12/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is initiated by excessive fat buildup in the liver, affecting around 35% of the world population. Various circumstances contribute to the initiation and progression of NAFLD, and it encompasses a wide range of disorders, from simple steatosis to nonalcoholic steatohepatitis (NASH), cirrhosis, and liver cancer. Although several treatments have been proposed, there is no definitive cure for NAFLD. In recent decades, several medications related to other metabolic disorders have been evaluated in preclinical studies and in clinical trials due to the correlation of NAFLD with other metabolic diseases. Fenofibrate is a fibrate drug approved for dyslipidemia that could be used for modulation of hepatic fat accumulation, targeting peroxisome proliferator-activator receptors, and de novo lipogenesis. This drug offers potential therapeutic efficacy for NAFLD due to its capacity to decrease the accumulation of hepatic lipids, as well as its antioxidant, anti-inflammatory, and antifibrotic properties. To better elucidate the pathophysiological processes underlying NAFLD, as well as to test therapeutic agents/interventions, experimental animal models have been extensively used. In this article, we first reviewed experimental animal models that have been used to evaluate the protective effects of fenofibrate on NAFLD/NASH. Next, we investigated the impact of fenofibrate on the hepatic microcirculation in NAFLD and then summarized the beneficial effects of fenofibrate, as compared to other drugs, for the treatment of NAFLD. Lastly, we discuss possible adverse side effects of fenofibrate on the liver.
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Mahmoudi A, Jamialahmadi T, Johnston TP, Sahebkar A. Impact of fenofibrate on NAFLD/NASH: A genetic perspective. Drug Discov Today 2022; 27:2363-2372. [PMID: 35569762 DOI: 10.1016/j.drudis.2022.05.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 01/13/2022] [Accepted: 05/09/2022] [Indexed: 11/26/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD), caused by an accumulation of fat deposits in hepatocytes, prevalently affects at least one-third of the world's population. The progression of this disorder can potentially include a spectrum of consecutive stages, specifically: steatosis, steatohepatitis and cirrhosis. Fenofibrate exhibits potential therapeutic efficacy for NAFLD owing to several properties, which include antioxidant, apoptotic, anti-inflammatory and antifibrotic activity. In the present review, we discuss the direct or indirect impact of fenofibrate on genes involved at various stages in the progression of NAFLD. Moreover, we have reviewed studies that compare fenofibrate with other drugs in treating NAFLD, as well as recent clinical trials, in an attempt to identify reliable scientific and clinical evidence concerning the therapeutic effects and benefits of fenofibrate on NAFLD. Teaser.
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Affiliation(s)
- Ali Mahmoudi
- Department of Medical Biotechnology and Nanotechnology, Faculty of Medicine, Mashhad University of Medical Sciences, Iran
| | - Tannaz Jamialahmadi
- Department of Nutrition, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Thomas P Johnston
- Division of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, MO 64108, USA
| | - Amirhossein Sahebkar
- Biotechnology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
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Target Deconvolution of Fenofibrate in Nonalcoholic Fatty Liver Disease Using Bioinformatics Analysis. BIOMED RESEARCH INTERNATIONAL 2022; 2021:3654660. [PMID: 34988225 PMCID: PMC8720586 DOI: 10.1155/2021/3654660] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/12/2021] [Accepted: 12/14/2021] [Indexed: 01/30/2023]
Abstract
Background Nonalcoholic fatty liver disease (NAFLD) is a prevalent form of liver damage, affecting ~25% of the global population. NAFLD comprises a spectrum of liver pathologies, from hepatic steatosis to nonalcoholic steatohepatitis (NASH), and may progress to liver fibrosis and cirrhosis. The presence of NAFLD correlates with metabolic disorders such as hyperlipidemia, obesity, blood hypertension, cardiovascular, and insulin resistance. Fenofibrate is an agonist drug for peroxisome proliferator-activated receptor alpha (PPARα), used principally for treatment of hyperlipidemia. However, fenofibrate has recently been investigated in clinical trials for treatment of other metabolic disorders such as diabetes, cardiovascular disease, and NAFLD. The evidence to date indicates that fenofibrate could improve NAFLD. While PPARα is considered to be the main target of fenofibrate, fenofibrate may exert its effect through impact on other genes and pathways thereby alleviating, and possibly reversing, NAFLD. In this study, using bioinformatics tools and gene-drug, gene-diseases databases, we sought to explore possible targets, interactions, and pathways involved in fenofibrate and NAFLD. Methods We first determined significant protein interactions with fenofibrate in the STITCH database with high confidence (0.7). Next, we investigated the identified proteins on curated targets in two databases, including the DisGeNET and DISEASES databases, to determine their association with NAFLD. We finally constructed a Venn diagram for these two collections (curated genes-NAFLD and fenofibrate-STITCH) to uncover possible primary targets of fenofibrate. Then, Gene Ontology (GO) and KEGG were analyzed to detect the significantly involved targets in molecular function, biological process, cellular component, and biological pathways. A P value < 0.01 was considered the cut-off criterion. We also estimated the specificity of targets with NAFLD by investigating them in disease-gene associations (STRING) and EnrichR (DisGeNET). Finally, we verified our findings in the scientific literature. Results We constructed two collections, one with 80 protein-drug interactions and the other with 95 genes associated with NAFLD. Using the Venn diagram, we identified 11 significant targets including LEP, SIRT1, ADIPOQ, PPARA, SREBF1, LDLR, GSTP1, VLDLR, SCARB1, MMP1, and APOC3 and then evaluated their biological pathways. Based on Gene Ontology, most of the targets are involved in lipid metabolism, and KEGG enrichment pathways showed the PPAR signaling pathway, AMPK signaling pathway, and NAFLD as the most significant pathways. The interrogation of those targets on authentic disease databases showed they were more specific to both steatosis and steatohepatitis liver injury than to any other diseases in these databases. Finally, we identified three significant genes, APOC3, PPARA, and SREBF1, that showed robust drug interaction with fenofibrate. Conclusion Fenofibrate may exert its effect directly or indirectly, via modulation of several key targets and pathways, in the treatment of NAFLD.
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Hwang S, Chung KW. Targeting fatty acid metabolism for fibrotic disorders. Arch Pharm Res 2021; 44:839-856. [PMID: 34664210 DOI: 10.1007/s12272-021-01352-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 10/11/2021] [Indexed: 02/06/2023]
Abstract
Fibrosis is defined by abnormal accumulation of extracellular matrix, which can affect virtually every organ system under diseased conditions. Fibrotic tissue remodeling often leads to organ dysfunction and is highly associated with increased morbidity and mortality. The disease burden caused by fibrosis is substantial, and the medical need for effective antifibrotic therapies is essential. Significant progress has been made in understanding the molecular mechanism and pathobiology of fibrosis, such as transforming growth factor-β (TGF-β)-mediated signaling pathways. However, owing to the complex and dynamic properties of fibrotic disorders, there are currently no therapeutic options that can prevent or reverse fibrosis. Recent studies have revealed that alterations in fatty acid metabolic processes are common mechanisms and core pathways that play a central role in different fibrotic disorders. Excessive lipid accumulation or defective fatty acid oxidation is associated with increased lipotoxicity, which directly contributes to the development of fibrosis. Genetic alterations or pharmacologic targeting of fatty acid metabolic processes have great potential for the inhibition of fibrosis development. Furthermore, mechanistic studies have revealed active interactions between altered metabolic processes and fibrosis development. Several well-known fibrotic factors change the lipid metabolic processes, while altered metabolic processes actively participate in fibrosis development. This review summarizes the recent evidence linking fatty acid metabolism and fibrosis, and provides new insights into the pathogenesis of fibrotic diseases for the development of drugs for fibrosis prevention and treatment.
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Affiliation(s)
- Seonghwan Hwang
- College of Pharmacy, Pusan National University, Busan, 46214, Republic of Korea
| | - Ki Wung Chung
- College of Pharmacy, Pusan National University, Busan, 46214, Republic of Korea.
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Park S, Song J, Baek IJ, Jang KY, Han CY, Jun DW, Kim PK, Raught B, Jin EJ. Loss of Acot12 contributes to NAFLD independent of lipolysis of adipose tissue. Exp Mol Med 2021; 53:1159-1169. [PMID: 34285335 PMCID: PMC8333268 DOI: 10.1038/s12276-021-00648-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 05/11/2021] [Accepted: 06/03/2021] [Indexed: 12/20/2022] Open
Abstract
In this study, we hypothesized that deregulation in the maintenance of the pool of coenzyme A (CoA) may play a crucial role in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). Specific deletion of Acot12 (Acot12-/-), the major acyl-CoA thioesterase, induced the accumulation of acetyl-CoA and resulted in the stimulation of de novo lipogenesis (DNL) and cholesterol biosynthesis in the liver. KEGG pathway analysis suggested PPARα signaling as the most significantly enriched pathway in Acot12-/- livers. Surprisingly, the exposure of Acot12-/- hepatocytes to fenofibrate significantly increased the accumulation of acetyl-CoA and resulted in the stimulation of cholesterol biosynthesis and DNL. Interaction analysis, including proximity-dependent biotin identification (BioID) analysis, suggested that ACOT12 may directly interact with vacuolar protein sorting-associated protein 33A (VPS33A) and play a role in vesicle-mediated cholesterol trafficking and the process of lysosomal degradation of cholesterol in hepatocytes. In summary, in this study, we found that ACOT12 deficiency is responsible for the pathogenesis of NAFLD through the accumulation of acetyl-CoA and the stimulation of DNL and cholesterol via activation of PPARα and inhibition of cholesterol trafficking.
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Affiliation(s)
- Sujeong Park
- Department of Biological Sciences, College of Natural Sciences, Wonkwang University, Iksan, Jeonbuk, Republic of Korea
| | - Jinsoo Song
- Department of Biological Sciences, College of Natural Sciences, Wonkwang University, Iksan, Jeonbuk, Republic of Korea
| | - In-Jeoung Baek
- Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Kyu Yun Jang
- Department of Pathology, Jeonbuk National University Medical School, Jeonju, Republic of Korea
- Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital and Research Institute for Endocrine Sciences, Jeonju, Republic of Korea
| | - Chang Yeob Han
- School of Pharmacy, Jeonbuk National University, Jeonju, Jeonbuk, Republic of Korea
| | - Dae Won Jun
- Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Republic of Korea
| | - Peter K Kim
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
- Program of Cell Biology, Hospital for Sick Children, Toronto, ON, Canada
| | - Brian Raught
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Princess Margaret Cancer Center, University Health Network, Toronto, ON, Canada
| | - Eun-Jung Jin
- Department of Biological Sciences, College of Natural Sciences, Wonkwang University, Iksan, Jeonbuk, Republic of Korea.
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Kumar A, Sundaram K, Mu J, Dryden GW, Sriwastva MK, Lei C, Zhang L, Qiu X, Xu F, Yan J, Zhang X, Park JW, Merchant ML, Bohler HCL, Wang B, Zhang S, Qin C, Xu Z, Han X, McClain CJ, Teng Y, Zhang HG. High-fat diet-induced upregulation of exosomal phosphatidylcholine contributes to insulin resistance. Nat Commun 2021; 12:213. [PMID: 33431899 PMCID: PMC7801461 DOI: 10.1038/s41467-020-20500-w] [Citation(s) in RCA: 134] [Impact Index Per Article: 44.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 11/30/2020] [Indexed: 12/15/2022] Open
Abstract
High-fat diet (HFD) decreases insulin sensitivity. How high-fat diet causes insulin resistance is largely unknown. Here, we show that lean mice become insulin resistant after being administered exosomes isolated from the feces of obese mice fed a HFD or from patients with type II diabetes. HFD altered the lipid composition of exosomes from predominantly phosphatidylethanolamine (PE) in exosomes from lean animals (L-Exo) to phosphatidylcholine (PC) in exosomes from obese animals (H-Exo). Mechanistically, we show that intestinal H-Exo is taken up by macrophages and hepatocytes, leading to inhibition of the insulin signaling pathway. Moreover, exosome-derived PC binds to and activates AhR, leading to inhibition of the expression of genes essential for activation of the insulin signaling pathway, including IRS-2, and its downstream genes PI3K and Akt. Together, our results reveal HFD-induced exosomes as potential contributors to the development of insulin resistance. Intestinal exosomes thus have potential as broad therapeutic targets.
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Affiliation(s)
- Anil Kumar
- James Graham Brown Cancer Center, Department of Microbiology & Immunology, University of Louisville, Louisville, KY, 40202, USA
| | - Kumaran Sundaram
- James Graham Brown Cancer Center, Department of Microbiology & Immunology, University of Louisville, Louisville, KY, 40202, USA
| | - Jingyao Mu
- James Graham Brown Cancer Center, Department of Microbiology & Immunology, University of Louisville, Louisville, KY, 40202, USA
| | - Gerald W Dryden
- James Graham Brown Cancer Center, Department of Microbiology & Immunology, University of Louisville, Louisville, KY, 40202, USA
- Department of Medicine, University of Louisville, Louisville, KY, 40202, USA
| | - Mukesh K Sriwastva
- James Graham Brown Cancer Center, Department of Microbiology & Immunology, University of Louisville, Louisville, KY, 40202, USA
| | - Chao Lei
- James Graham Brown Cancer Center, Department of Microbiology & Immunology, University of Louisville, Louisville, KY, 40202, USA
| | - Lifeng Zhang
- James Graham Brown Cancer Center, Department of Microbiology & Immunology, University of Louisville, Louisville, KY, 40202, USA
| | - Xiaolan Qiu
- James Graham Brown Cancer Center, Department of Microbiology & Immunology, University of Louisville, Louisville, KY, 40202, USA
| | - Fangyi Xu
- James Graham Brown Cancer Center, Department of Microbiology & Immunology, University of Louisville, Louisville, KY, 40202, USA
| | - Jun Yan
- James Graham Brown Cancer Center, Department of Microbiology & Immunology, University of Louisville, Louisville, KY, 40202, USA
| | - Xiang Zhang
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, 40202, USA
| | - Juw Won Park
- Department of Computer Engineering and Computer Science, University of Louisville, Louisville, KY, 40202, USA
- KBRIN Bioinformatics Core, University of Louisville, Louisville, KY, 40202, USA
| | - Michael L Merchant
- Kidney Disease Program and Clinical Proteomics Center, University of Louisville, Louisville, KY, USA
| | - Henry C L Bohler
- Department of Reproductive Endocrinology and Infertility, University of Louisville, Louisville, KY40202, USA
| | - Baomei Wang
- Department of Dermatology, University of Pennsylvania, Philadelphia, 19104, USA
| | - Shuangqin Zhang
- Peeples Cancer Institute, 215 Memorial Drive, Dalton, GA, 30720, USA
| | - Chao Qin
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - Ziying Xu
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - Xianlin Han
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - Craig J McClain
- Department of Medicine, University of Louisville, Louisville, KY, 40202, USA
| | - Yun Teng
- James Graham Brown Cancer Center, Department of Microbiology & Immunology, University of Louisville, Louisville, KY, 40202, USA.
| | - Huang-Ge Zhang
- James Graham Brown Cancer Center, Department of Microbiology & Immunology, University of Louisville, Louisville, KY, 40202, USA.
- Robley Rex Veterans Affairs Medical Center, Louisville, KY, 40206, USA.
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12
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Wan S, Veen JN, N'Goma JCB, Nelson RC, Vance DE, Jacobs RL. Hepatic PEMT activity mediates liver health, weight gain, and insulin resistance. FASEB J 2019; 33:10986-10995. [DOI: 10.1096/fj.201900679r] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Sereana Wan
- Department of BiochemistryUniversity of AlbertaEdmontonAlbertaCanada
| | - Jelske N. Veen
- Department of BiochemistryUniversity of AlbertaEdmontonAlbertaCanada
| | | | - Randal C. Nelson
- Department of BiochemistryUniversity of AlbertaEdmontonAlbertaCanada
| | - Dennis E. Vance
- Department of BiochemistryUniversity of AlbertaEdmontonAlbertaCanada
| | - René L. Jacobs
- Department of BiochemistryUniversity of AlbertaEdmontonAlbertaCanada
- Department of Agricultural, Food, and Nutritional ScienceUniversity of AlbertaEdmontonAlbertaCanada
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13
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Wan S, Kuipers F, Havinga R, Ando H, Vance DE, Jacobs RL, van der Veen JN. Impaired Hepatic Phosphatidylcholine Synthesis Leads to Cholestasis in Mice Challenged With a High-Fat Diet. Hepatol Commun 2019; 3:262-276. [PMID: 30766963 PMCID: PMC6357837 DOI: 10.1002/hep4.1302] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 11/28/2018] [Indexed: 01/05/2023] Open
Abstract
Phosphatidylethanolamine N-methyltransferase (PEMT) is a hepatic integral membrane protein localized to the endoplasmic reticulum (ER). PEMT catalyzes approximately 30% of hepatic phosphatidylcholine (PC) biosynthesis. Pemt-/- mice fed a high-fat diet (HFD) develop steatohepatitis. Interestingly, portions of the ER located close to the canaliculus are enriched in PEMT. Phospholipid balance and asymmetrical distribution by adenosine triphosphatase phospholipid transporting 8B1 (ATP8B1) on the canalicular membrane is required for membrane integrity and biliary processes. We hypothesized that PEMT is an important supplier of PC to the canaliculus and that PEMT activity is critical for the maintenance of canalicular membrane integrity and bile formation following HFD feeding when there is an increase in overall hepatic PC demand. Pemt+/+ and Pemt-/- mice were fed a chow diet, an HFD, or a choline-supplemented HFD. Plasma and hepatic indices of liver function and parameters of bile formation were determined. Pemt-/- mice developed cholestasis, i.e, elevated plasma bile acid (BA) concentrations and decreased biliary secretion rates of BAs and PC, during HFD feeding. The maximal BA secretory rate was reduced more than 70% in HFD-fed Pemt-/- mice. Hepatic ABCB11/bile salt export protein, responsible for BA secretion, was decreased in Pemt-/- mice and appeared to be retained intracellularly. Canalicular membranes of HFD-fed Pemt-/- mice contained fewer invaginations and displayed a smaller surface area than Pemt+/+ mice. Choline supplementation (CS) prevented and reversed the development of HFD-induced cholestasis. Conclusion: We propose that hepatic PC availability is critical for bile formation. Dietary CS might be a potential noninvasive therapy for a specific subset of patients with cholestasis.
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Affiliation(s)
- Sereana Wan
- Group on the Molecular and Cell Biology of Lipids and Department of Biochemistry University of Alberta Edmonton Canada
| | - Folkert Kuipers
- Department of Pediatrics University of Groningen, University Medical Center Groningen Groningen the Netherlands
| | - Rick Havinga
- Department of Pediatrics University of Groningen, University Medical Center Groningen Groningen the Netherlands
| | - Hiromi Ando
- Group on the Molecular and Cell Biology of Lipids and Department of Biochemistry University of Alberta Edmonton Canada
| | - Dennis E Vance
- Group on the Molecular and Cell Biology of Lipids and Department of Biochemistry University of Alberta Edmonton Canada
| | - René L Jacobs
- Group on the Molecular and Cell Biology of Lipids and Department of Biochemistry University of Alberta Edmonton Canada.,Department of Agricultural, Food and Nutritional Science University of Alberta Edmonton Canada
| | - Jelske N van der Veen
- Group on the Molecular and Cell Biology of Lipids and Department of Biochemistry University of Alberta Edmonton Canada
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14
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Jung JY, Choi Y, Suh CH, Yoon D, Kim HA. Effect of fenofibrate on uric acid level in patients with gout. Sci Rep 2018; 8:16767. [PMID: 30425304 PMCID: PMC6233215 DOI: 10.1038/s41598-018-35175-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 10/29/2018] [Indexed: 12/18/2022] Open
Abstract
Gout is a chronic disease associated with deposition of monosodium urate crystals and accompanied by diabetes, hypertension, and dyslipidemia. Hypertriglyceridemia is common among patients with gout, and fenofibrate is usually used to reduce triglyceride levels. The aim of this study is to determine the effect of uric acid reduction by fenofibrate in patients with gout administered uric acid lowering agents (viz., the xanthine oxidase inhibitors allopurinol and febuxostat). Data from 863 patients with gout were collected from electronic medical records comprising information on underlying diseases, laboratory findings, and drug histories. Among all the patients, 70 (8.11%) took fenofibrate with allopurinol or febuxostat. Male and young patients took fenofibrate more frequently, and hypertension was less frequent in patients administered xanthine oxidase inhibitors and fenofibrate than in those administered only xanthine oxidase inhibitors. After the treatment, serum uric acid levels more significantly decreased (−1.81 ± 2.41 vs. −2.40 ± 2.28 mg/dL, p = 0.043) in patients with fenofibrate cotreatment, than in those administered allopurinol or febuxostat alone. The effect of uric acid reduction was larger (b = −1.098, p < 0.001) in patients taking glucocorticoids than in those administered other treatments. There was no difference in the levels of creatinine, blood urea nitrogen, and aminotransferases between patients treated with and without fenofibrate. Fenofibrate additionally reduced uric acid levels without showing any change in the results of renal or liver function tests, suggesting that the addition of fenofibrate is a reasonable option for treating gout in patients having high triglyceride levels.
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Affiliation(s)
- Ju-Yang Jung
- Department of Rheumatology, Ajou University School of Medicine, 164 Worldcup-ro, Yeongtong-gu, Suwon, 16499, Korea
| | - Young Choi
- Department of Biomedical Informatics, Ajou University School of Medicine, 164 Worldcup-ro, Yeongtong-gu, Suwon, 16499, Korea.,Department of Biomedical Science, Ajou University School of Medicine, 164 Worldcup-ro, Yeongtong-gu, Suwon, 16499, Korea
| | - Chang-Hee Suh
- Department of Rheumatology, Ajou University School of Medicine, 164 Worldcup-ro, Yeongtong-gu, Suwon, 16499, Korea
| | - Dukyong Yoon
- Department of Biomedical Informatics, Ajou University School of Medicine, 164 Worldcup-ro, Yeongtong-gu, Suwon, 16499, Korea. .,Department of Biomedical Science, Ajou University School of Medicine, 164 Worldcup-ro, Yeongtong-gu, Suwon, 16499, Korea.
| | - Hyoun-Ah Kim
- Department of Rheumatology, Ajou University School of Medicine, 164 Worldcup-ro, Yeongtong-gu, Suwon, 16499, Korea.
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15
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Vitamin E alleviates non-alcoholic fatty liver disease in phosphatidylethanolamine N-methyltransferase deficient mice. Biochim Biophys Acta Mol Basis Dis 2018; 1865:14-25. [PMID: 30300671 DOI: 10.1016/j.bbadis.2018.10.010] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 09/27/2018] [Accepted: 10/05/2018] [Indexed: 02/06/2023]
Abstract
Phosphatidylethanolamine N-methyltransferase (PEMT) converts phosphatidylethanolamine (PE) to phosphatidylcholine (PC), mainly in the liver. Pemt-/- mice are protected from high-fat diet (HFD)-induced obesity and insulin resistance, but develop severe non-alcoholic fatty liver disease (NAFLD) when fed a HFD, mostly due to impaired VLDL secretion. Oxidative stress is thought to be an essential factor in the progression from simple steatosis to steatohepatitis. Vitamin E is an antioxidant that has been clinically used to improve NAFLD pathology. Our aim was to determine whether supplementation of the diet with vitamin E could attenuate HFD-induced hepatic steatosis and its progression to NASH in Pemt-/- mice. Treatment with vitamin E (0.5 g/kg) for 3 weeks improved VLDL-TG secretion and normalized cholesterol metabolism, but failed to reduce hepatic TG content. Moreover, vitamin E treatment was able to reduce hepatic oxidative stress, inflammation and fibrosis. We also observed abnormal ceramide metabolism in Pemt-/- mice fed a HFD, with elevation of ceramides and other sphingolipids and higher expression of mRNAs for acid ceramidase (Asah1) and ceramide kinase (Cerk). Interestingly, vitamin E supplementation restored Asah1 and Cerk mRNA and sphingolipid levels. Together this study shows that vitamin E treatment efficiently prevented the progression from simple steatosis to steatohepatitis in mice lacking PEMT.
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16
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Zia Y, Al Rajabi A, Mi S, Ju T, Leonard KA, Nelson R, Thiesen A, Willing BP, Field CJ, Curtis JM, van der Veen JN, Jacobs RL. Hepatic Expression of PEMT, but Not Dietary Choline Supplementation, Reverses the Protection against Atherosclerosis in Pemt-/-/Ldlr-/- Mice. J Nutr 2018; 148:1513-1520. [PMID: 30281112 DOI: 10.1093/jn/nxy165] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 07/03/2018] [Indexed: 01/11/2023] Open
Abstract
Background Phosphatidylethanolamine N-methyltransferase (PEMT) converts phosphatidylethanolamine to phosphatidylcholine. Pemt-/-/low density lipoprotein receptor (Ldlr)-/- mice have significantly reduced plasma lipids and are protected against atherosclerosis. Recent studies have shown that choline can be metabolized by the gut flora into trimethylamine-N-oxide (TMAO), which is an emerging risk factor for atherosclerosis. Objective The objective of this study was to determine whether ectopic hepatic PEMT expression or choline supplementation would promote atherosclerosis in Pemt-/-/Ldlr-/- mice. Methods Male 8- to 10-wk-old Pemt+/+/Ldlr-/- (SKO) and Pemt-/-/Ldlr-/- (DKO) mice were injected with an adeno-associated virus (AAV) expressing green fluorescent protein (GFP) or human PEMT and fed a Western diet (40% of calories from fat, 0.5% cholesterol) for 8 wk. In a separate experiment, 8- to 10-wk-old SKO and half of the DKO male mice were fed a Western diet with normal (3 g/kg) choline for 12 wk. The remaining DKO mice [choline-supplemented (CS) DKO] were fed a CS Western diet (10 g choline/kg). Plasma lipid concentrations, choline metabolites, and aortic atherosclerosis were measured. Results Plasma cholesterol, plasma TMAO, and aortic atherosclerosis were reduced by 60%, 40%, and 80%, respectively, in DKO mice compared with SKO mice. AAV-PEMT administration increased plasma cholesterol and TMAO by 30% and 40%, respectively, in DKO mice compared with AAV-GFP-treated DKO mice. Furthermore, AAV-PEMT-injected DKO mice developed atherosclerotic lesions similar to SKO mice. In the second study, there was no difference in atherosclerosis or plasma cholesterol between DKO and CS-DKO mice. However, plasma TMAO concentrations were increased 2.5-fold in CS-DKO mice compared with DKO mice. Conclusions Reintroducing hepatic PEMT reversed the atheroprotective phenotype of DKO mice. Choline supplementation did not increase atherosclerosis or plasma cholesterol in DKO mice. Our data suggest that plasma TMAO does not induce atherosclerosis when plasma cholesterol is low. Furthermore, this is the first report to our knowledge that suggests that de novo choline synthesis alters TMAO status.
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Affiliation(s)
- Yumna Zia
- Departments of Agricultural, Food, and Nutritional Science
| | - Ala Al Rajabi
- Departments of Agricultural, Food, and Nutritional Science
| | - Si Mi
- Departments of Agricultural, Food, and Nutritional Science
| | - Tingting Ju
- Departments of Agricultural, Food, and Nutritional Science
| | | | | | - Aducio Thiesen
- Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada
| | | | | | | | | | - René L Jacobs
- Departments of Agricultural, Food, and Nutritional Science.,Biochemistry
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17
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Monteillet L, Gjorgjieva M, Silva M, Verzieux V, Imikirene L, Duchampt A, Guillou H, Mithieux G, Rajas F. Intracellular lipids are an independent cause of liver injury and chronic kidney disease in non alcoholic fatty liver disease-like context. Mol Metab 2018; 16:100-115. [PMID: 30100243 PMCID: PMC6157648 DOI: 10.1016/j.molmet.2018.07.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 07/19/2018] [Accepted: 07/23/2018] [Indexed: 12/15/2022] Open
Abstract
Objective Ectopic lipid accumulation in the liver and kidneys is a hallmark of metabolic diseases leading to non-alcoholic fatty liver disease (NAFLD) and chronic kidney disease (CKD). Moreover, recent data have highlighted a strong correlation between NAFLD and CKD incidences. In this study, we use two mouse models of hepatic steatosis or CKD, each initiated independently of the other upon the suppression of glucose production specifically in the liver or kidneys, to elucidate the mechanisms underlying the development of CKD in the context of NAFLD-like pathology. Methods Mice with a deletion of G6pc, encoding glucose-6 phosphatase catalytic subunit, specifically in the liver (L.G6pc−/− mice) or the kidneys (K.G6pc−/− mice), were fed with either a standard diet or a high fat/high sucrose (HF/HS) diet during 9 months. These mice represent two original models of a rare metabolic disease named Glycogen Storage Disease Type Ia (GSDIa) that is characterized by both NAFLD-like pathology and CKD. Two other groups of L.G6pc−/− and K.G6pc−/− mice were fed a standard diet for 6 months and then treated with fenofibrate for 3 months. Lipid and glucose metabolisms were characterized, and NAFLD-like and CKD damages were evaluated. Results Lipid depot exacerbation upon high-calorie diet strongly accelerated hepatic and renal pathologies induced by the G6pc-deficiency. In L.G6pc−/− mice, HF/HS diet increased liver injuries, characterized by higher levels of plasmatic transaminases and increased hepatic tumor incidence. In K.G6pc−/− mice, HF/HS diet increased urinary albumin and lipocalin 2 excretion and aggravated renal fibrosis. In both cases, the worsening of NAFLD-like injuries and CKD was independent of glycogen content. Furthermore, fenofibrate, via the activation of lipid oxidation significantly decreased the hepatic or renal lipid accumulations and prevented liver or kidney damages in L.G6pc−/− and K.G6pc−/− mice, respectively. Finally, we show that L.G6pc−/− mice and K.G6pc−/− mice developed NAFLD-like pathology and CKD independently. Conclusions This study highlights the crucial role that lipids play in the independent development of both NAFLD and CKD and demonstrates the importance of lipid-lowering treatments in various metabolic diseases featured by lipid load, from the “rare” GSDIa to the “epidemic” morbid obesity or type 2 diabetes. Exacerbating lipid accumulation aggravates liver/kidney injury in GSDI. Fenofibrate-mediated PPARα activation induces hepatic and renal lipid turnover. Increased lipid turnover prevents glycogen synthesis and accumulation. PPARα–mediated metabolic reprograming prevents hepatic and renal GSDI complications. NAFLD and CKD develop independently.
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Affiliation(s)
- Laure Monteillet
- Institut National de la Santé et de la Recherche Médicale, U1213, Lyon, F-69008, France; Université de Lyon, Lyon, F-69008, France; Université Lyon1, Villeurbanne, F-69622, France.
| | - Monika Gjorgjieva
- Institut National de la Santé et de la Recherche Médicale, U1213, Lyon, F-69008, France; Université de Lyon, Lyon, F-69008, France; Université Lyon1, Villeurbanne, F-69622, France.
| | - Marine Silva
- Institut National de la Santé et de la Recherche Médicale, U1213, Lyon, F-69008, France; Université de Lyon, Lyon, F-69008, France; Université Lyon1, Villeurbanne, F-69622, France.
| | - Vincent Verzieux
- Institut National de la Santé et de la Recherche Médicale, U1213, Lyon, F-69008, France; Université de Lyon, Lyon, F-69008, France; Université Lyon1, Villeurbanne, F-69622, France.
| | - Linda Imikirene
- Institut National de la Santé et de la Recherche Médicale, U1213, Lyon, F-69008, France; Université de Lyon, Lyon, F-69008, France; Université Lyon1, Villeurbanne, F-69622, France.
| | - Adeline Duchampt
- Institut National de la Santé et de la Recherche Médicale, U1213, Lyon, F-69008, France; Université de Lyon, Lyon, F-69008, France; Université Lyon1, Villeurbanne, F-69622, France.
| | - Hervé Guillou
- Toxalim, Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse, 31027, France.
| | - Gilles Mithieux
- Institut National de la Santé et de la Recherche Médicale, U1213, Lyon, F-69008, France; Université de Lyon, Lyon, F-69008, France; Université Lyon1, Villeurbanne, F-69622, France.
| | - Fabienne Rajas
- Institut National de la Santé et de la Recherche Médicale, U1213, Lyon, F-69008, France; Université de Lyon, Lyon, F-69008, France; Université Lyon1, Villeurbanne, F-69622, France.
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18
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Animal models of NAFLD from the pathologist's point of view. Biochim Biophys Acta Mol Basis Dis 2018; 1865:929-942. [PMID: 29746920 DOI: 10.1016/j.bbadis.2018.04.024] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 04/25/2018] [Accepted: 04/30/2018] [Indexed: 01/18/2023]
Abstract
Fatty liver disease is a multifactorial world-wide health problem resulting from a complex interplay between liver, adipose tissue and intestine and initiated by alcohol abuse, overeating, various types of intoxication, adverse drug reactions and genetic or acquired metabolic defects. Depending on etiology fatty liver disease is commonly categorized as alcoholic or non-alcoholic. Both types may progress from simple steatosis to the necro-inflammatory lesion of alcoholic (ASH) and non-alcoholic steatohepatitis (NASH), respectively, and finally to cirrhosis and hepatocellular carcinoma. Animal models are helpful to clarify aspects of pathogenesis and progression. Generally, they are classified as nutritional (dietary), toxin-induced and genetic, respectively, or represent a combination of these factors. Numerous reviews are dealing with NASH animal models designed to imitate as closely as possible the metabolic situation associated with human disease. This review focuses on currently used mouse models of NASH with particular emphasis on liver morphology. Despite metabolic similarities most models (except those with chemically or genetically induced porphyria or keratin 18-deficiency) fail to develop the morphologic key features of NASH, namely hepatocyte ballooning and formation of histologically and immunohistochemically well-defined Mallory-Denk-Bodies (MDBs). Although MDBs are not universally detectable in ballooned hepatocytes in NASH their experimental reproduction and analysis may, however, significantly contribute to our understanding of important pathogenic aspects of NASH despite the obvious differences in etiology.
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19
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Dave T, Tilles AW, Vemula M. A Cell-Based Assay to Investigate Hypolipidemic Effects of Nonalcoholic Fatty Liver Disease Therapeutics. SLAS DISCOVERY 2017; 23:274-282. [PMID: 29132235 DOI: 10.1177/2472555217741077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In the recent past, there has been a growing interest in developing nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) therapeutics. As a result, a need for in vitro cell models of human hepatic steatosis and high-throughput assays to measure intracellular lipid levels has arisen. To address this growing need, we optimized the conditions based on the current literature to fatten HepG2 hepatocytes by adding a mixture of saturated and unsaturated fatty acids (oleate/palmitate, 2:1 molar ratio) without inducing any overt cytotoxicity. Our results indicate that hepatocytes fatten in a concentration- (0.75-1.5 mM of fatty acids) and time-dependent manner, with a substantial increase in intracellular lipid levels seen within 6 h. Additionally, a method to quantify lipid levels in cells using a fluorescent reagent that is more sensitive than that in conventional assays and adaptable for high-throughput screening is presented. Lastly, the utility of the in vitro cell model and an assay based on AdipoRed to measure hypolipidemic effects of therapeutic drugs is demonstrated using fenofibrate, a molecule that was previously shown to lower lipid levels in the liver.
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