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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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Wang J, Li J, Fu Y, Zhu Y, Lin L, Li Y. Research progress, challenges and perspectives of phospholipids metabolism in the LXR‑LPCAT3 signaling pathway and its relation to NAFLD (Review). Int J Mol Med 2024; 53:32. [PMID: 38362962 PMCID: PMC10903931 DOI: 10.3892/ijmm.2024.5356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 01/16/2024] [Indexed: 02/17/2024] Open
Abstract
Phospholipids (PLs) are principle constituents of biofilms, with their fatty acyl chain composition significantly impacting the biophysical properties of membranes, thereby influencing biological processes. Recent studies have elucidated that fatty acyl chains, under the enzymatic action of lyso‑phosphatidyl‑choline acyltransferases (LPCATs), expedite incorporation into the sn‑2 site of phosphatidyl‑choline (PC), profoundly affecting pathophysiology. Accumulating evidence suggests that alterations in LPCAT activity are implicated in various diseases, including non‑alcoholic fatty liver disease (NAFLD), hepatitis C, atherosclerosis and cancer. Specifically, LPCAT3 is instrumental in maintaining systemic lipid homeostasis through its roles in hepatic lipogenesis, intestinal lipid absorption and lipoprotein secretion. The liver X receptor (LXR), pivotal in lipid homeostasis, modulates cholesterol, fatty acid (FA) and PL metabolism. LXR's capacity to modify PL composition in response to cellular sterol fluctuations is a vital mechanism for protecting biofilms against lipid stress. Concurrently, LXR activation enhances LPCAT3 expression on cell membranes and elevates polyunsaturated PL levels. This activation can ameliorate saturated free FA effects in vitro or endoplasmic reticulum stress in vivo due to lipid accumulation in hepatic cells. Pharmacological interventions targeting LXR, LPCAT and membrane PL components could offer novel therapeutic directions for NAFLD management. The present review primarily focused on recent advancements in understanding the LPCAT3 signaling pathway's role in lipid metabolism related to NAFLD, aiming to identify new treatment targets for the disease.
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Affiliation(s)
- Junmin Wang
- Department of Gastroenterology, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200071, P.R. China
| | - Jiacheng Li
- Department of Gastroenterology, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200071, P.R. China
| | - Yugang Fu
- Department of Gastroenterology, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200071, P.R. China
| | - Yingying Zhu
- Department of Gastroenterology, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200071, P.R. China
| | - Liubing Lin
- Department of Gastroenterology, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200071, P.R. China
| | - Yong Li
- Department of Gastroenterology, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200071, P.R. China
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Valentine WJ, Yanagida K, Kawana H, Kono N, Noda NN, Aoki J, Shindou H. Update and nomenclature proposal for mammalian lysophospholipid acyltransferases which create membrane phospholipid diversity. J Biol Chem 2021; 298:101470. [PMID: 34890643 PMCID: PMC8753187 DOI: 10.1016/j.jbc.2021.101470] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 11/23/2021] [Indexed: 12/13/2022] Open
Abstract
The diversity of glycerophospholipid species in cellular membranes is immense and affects various biological functions. Glycerol-3-phosphate acyltransferases (GPATs) and lysophospholipid acyltransferases (LPLATs), in concert with phospholipase A1/2s enzymes, contribute to this diversity via selective esterification of fatty acyl chains at the sn-1 or sn-2 positions of membrane phospholipids. These enzymes are conserved across all kingdoms, and in mammals four GPATs of the 1-acylglycerol-3-phosphate O-acyltransferase (AGPAT) family and at least 14 LPLATs, either of the AGPAT or the membrane-bound O-acyltransferase (MBOAT) families, have been identified. Here we provide an overview of the biochemical and biological activities of these mammalian enzymes, including their predicted structures, involvements in human diseases, and essential physiological roles as revealed by gene-deficient mice. Recently, the nomenclature used to refer to these enzymes has generated some confusion due to the use of multiple names to refer to the same enzyme and instances of the same name being used to refer to completely different enzymes. Thus, this review proposes a more uniform LPLAT enzyme nomenclature, as well as providing an update of recent advances made in the study of LPLATs, continuing from our JBC mini review in 2009.
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Affiliation(s)
- William J Valentine
- Department of Lipid Signaling, National Center for Global Health and Medicine (NCGM), Shinjuku-ku, Tokyo 162-8655, Japan; Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Tokyo, 187-8502, Japan
| | - Keisuke Yanagida
- Department of Lipid Signaling, National Center for Global Health and Medicine (NCGM), Shinjuku-ku, Tokyo 162-8655, Japan
| | - Hiroki Kawana
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Nozomu Kono
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Nobuo N Noda
- Institute of Microbial Chemistry (BIKAKEN), Microbial Chemistry Research Foundation, Tokyo 141-0021, Japan
| | - Junken Aoki
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hideo Shindou
- Department of Lipid Signaling, National Center for Global Health and Medicine (NCGM), Shinjuku-ku, Tokyo 162-8655, Japan; Department of Lipid Medical Science, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
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Chean J, Chen CJ, Gugiu G, Wong P, Cha S, Li H, Nguyen T, Bhatticharya S, Shively JE. Human CEACAM1-LF regulates lipid storage in HepG2 cells via fatty acid transporter CD36. J Biol Chem 2021; 297:101311. [PMID: 34666041 PMCID: PMC8577156 DOI: 10.1016/j.jbc.2021.101311] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 10/07/2021] [Accepted: 10/14/2021] [Indexed: 12/12/2022] Open
Abstract
Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is expressed in the liver and secreted as biliary glycoprotein 1 (BGP1) via bile canaliculi (BCs). CEACAM1-LF is a 72 amino acid cytoplasmic domain mRNA splice isoform with two immunoreceptor tyrosine-based inhibitory motifs (ITIMs). Ceacam1−/− or Ser503Ala transgenic mice have been shown to develop insulin resistance and nonalcoholic fatty liver disease; however, the role of the human equivalent residue, Ser508, in lipid dysregulation is unknown. Human HepG2 hepatocytes that express CEACAM1 and form BC in vitro were compared with CEACAM1−/− cells and CEACAM1−/− cells expressing Ser508Ala null or Ser508Asp phosphorylation mimic mutations or to phosphorylation null mutations in the tyrosine ITIMs known to be phosphorylated by the tyrosine kinase Src. CEACAM1−/− cells and the Ser508Asp and Tyr520Phe mutants strongly retained lipids, while Ser508Ala and Tyr493Phe mutants had low lipid levels compared with wild-type cells, indicating that the ITIM mutants phenocopied the Ser508 mutants. We found that the fatty acid transporter CD36 was upregulated in the S508A mutant, coexpressed in BCs with CEACAM1, co-IPed with CEACAM1 and Src, and when downregulated via RNAi, an increase in lipid droplet content was observed. Nuclear translocation of CD36 associated kinase LKB1 was increased sevenfold in the S508A mutant versus CEACAM1−/− cells and correlated with increased activation of CD36-associated kinase AMPK in CEACAM1−/− cells. Thus, while CEACAM1−/− HepG2 cells upregulate lipid storage similar to Ceacam1−/− in murine liver, the null mutation Ser508Ala led to decreased lipid storage, emphasizing evolutionary changes between the CEACAM1 genes in mouse and humans.
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Affiliation(s)
- Jennifer Chean
- Department of Immunology and Theranostics, Beckman Research Institute of City of Hope, Duarte, California, USA
| | - Charng-Jui Chen
- Department of Immunology and Theranostics, Beckman Research Institute of City of Hope, Duarte, California, USA
| | - Gabriel Gugiu
- Department of Immunology and Theranostics, Beckman Research Institute of City of Hope, Duarte, California, USA
| | - Patty Wong
- Department of Immunology and Theranostics, Beckman Research Institute of City of Hope, Duarte, California, USA
| | - Seung Cha
- Department of Immunology and Theranostics, Beckman Research Institute of City of Hope, Duarte, California, USA
| | - Harry Li
- Department of Immunology and Theranostics, Beckman Research Institute of City of Hope, Duarte, California, USA
| | - Tung Nguyen
- Department of Immunology and Theranostics, Beckman Research Institute of City of Hope, Duarte, California, USA
| | - Supriyo Bhatticharya
- Department of Computational and Quantitative Medicine, Beckman Research Institute of City of Hope, Duarte, California, USA
| | - John E Shively
- Department of Immunology and Theranostics, Beckman Research Institute of City of Hope, Duarte, California, USA.
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Guo C, Xue Y, Sun D, Yin Y, Hu F, Mao S. Transcriptome profiling of hepatic and renal mRNAs and lncRNAs under a nutritional restriction during pregnancy in a sheep model. Genomics 2021; 113:2769-2779. [PMID: 34147634 DOI: 10.1016/j.ygeno.2021.06.023] [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: 09/13/2020] [Revised: 06/12/2021] [Accepted: 06/15/2021] [Indexed: 11/25/2022]
Abstract
This study aimed to investigate the transcriptome profiles of liver and kidney in pregnant sheep under a nutritional restriction. Twenty Hu sheep were segregated into control group (CON) and severe feed restriction (FR) group. Results showed that the concentration of insulin decreased, whereas glucagon, epinephrine, and norepinephrine increased in the FR group. Histological morphology showed no apparent difference in terms of fat deposition in the kidney. In addition, FR significantly decreased the hepatic gene expression of gluconeogenic genes. However, in the kidney, the relative mRNA expression levels of gluconeogenic genes and glucose transporter 1 were observed to increase while the mRNA expression of sodium-glucose co-transporter 1 were decreased by FR. The differentially expressed genes in the liver were associated with fatty acid metabolism and inflammation. In the kidney, FR mainly activated the gluconeogenesis improving negative energy balance. These results provide a better understanding of the consequences of starvation during pregnancy.
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Affiliation(s)
- Changzheng Guo
- Laboratory of Gastrointestinal Microbiology, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, Nanjing Agricultural University, Nanjing 210095, China; National Experimental Teaching Demonstration Center of Animal Science, Nanjing Agricultural University, Nanjing 210095, China; National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing 210095, China; Joint International Research Laboratory of Animal Health and Food Safety, Nanjing Agricultural University, Nanjing 210095, China
| | - Yanfeng Xue
- Laboratory of Gastrointestinal Microbiology, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, Nanjing Agricultural University, Nanjing 210095, China; National Experimental Teaching Demonstration Center of Animal Science, Nanjing Agricultural University, Nanjing 210095, China; National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing 210095, China; Joint International Research Laboratory of Animal Health and Food Safety, Nanjing Agricultural University, Nanjing 210095, China
| | - Daming Sun
- Laboratory of Gastrointestinal Microbiology, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, Nanjing Agricultural University, Nanjing 210095, China; National Experimental Teaching Demonstration Center of Animal Science, Nanjing Agricultural University, Nanjing 210095, China; National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing 210095, China; Joint International Research Laboratory of Animal Health and Food Safety, Nanjing Agricultural University, Nanjing 210095, China
| | - Yuyang Yin
- Huzhou Academy of Agricultural Sciences, Huzhou 313000, China
| | - Fan Hu
- Laboratory of Gastrointestinal Microbiology, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, Nanjing Agricultural University, Nanjing 210095, China; National Experimental Teaching Demonstration Center of Animal Science, Nanjing Agricultural University, Nanjing 210095, China; National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing 210095, China; Joint International Research Laboratory of Animal Health and Food Safety, Nanjing Agricultural University, Nanjing 210095, China
| | - Shengyong Mao
- Laboratory of Gastrointestinal Microbiology, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, Nanjing Agricultural University, Nanjing 210095, China; National Experimental Teaching Demonstration Center of Animal Science, Nanjing Agricultural University, Nanjing 210095, China; National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing 210095, China; Joint International Research Laboratory of Animal Health and Food Safety, Nanjing Agricultural University, Nanjing 210095, China.
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6
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Meroni M, Longo M, Fracanzani AL, Dongiovanni P. MBOAT7 down-regulation by genetic and environmental factors predisposes to MAFLD. EBioMedicine 2020; 57:102866. [PMID: 32629394 PMCID: PMC7339032 DOI: 10.1016/j.ebiom.2020.102866] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/12/2020] [Accepted: 06/16/2020] [Indexed: 12/11/2022] Open
Abstract
Metabolic associated fatty liver disease (MAFLD) encompasses a broad spectrum of hepatic disorders, which include steatosis, nonalcoholic steatohepatitis (NASH), fibrosis and cirrhosis, that is a critical risk factor for hepatocellular carcinoma (HCC) development. Its pathogenesis is intertwined with obesity and type 2 diabetes (T2D). However, the predisposition to develop MAFLD is severely influenced by environmental and inherited cues. The rs641738 variant close to MBOAT7 gene has been identified by a genome-wide association screening in heavy drinkers. Although this variant has been associated with the entire spectrum of MAFLD, these results have not been completely replicated and the debate is still opened. Thus, functional studies that unravel the biological mechanisms underlying the genetic association with fatty liver are required. This review aims to summarize the clinical and experimental findings regarding the rs641738 variation and MBOAT7 function, with the purpose to shed light to its role as novel player in MAFLD pathophysiology.
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Affiliation(s)
- Marica Meroni
- General Medicine and Metabolic Diseases, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milano, Milan, Italy; Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Milan, Italy
| | - Miriam Longo
- General Medicine and Metabolic Diseases, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milano, Milan, Italy; Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Milan, Italy
| | - Anna L Fracanzani
- General Medicine and Metabolic Diseases, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milano, Milan, Italy; Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Milan, Italy
| | - Paola Dongiovanni
- General Medicine and Metabolic Diseases, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milano, Milan, Italy.
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Valentine WJ, Hashidate-Yoshida T, Yamamoto S, Shindou H. Biosynthetic Enzymes of Membrane Glycerophospholipid Diversity as Therapeutic Targets for Drug Development. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1274:5-27. [PMID: 32894505 DOI: 10.1007/978-3-030-50621-6_2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Biophysical properties of membranes are dependent on their glycerophospholipid compositions. Lysophospholipid acyltransferases (LPLATs) selectively incorporate fatty chains into lysophospholipids to affect the fatty acid composition of membrane glycerophospholipids. Lysophosphatidic acid acyltransferases (LPAATs) of the 1-acylglycerol-3-phosphate O-acyltransferase (AGPAT) family incorporate fatty chains into phosphatidic acid during the de novo glycerophospholipid synthesis in the Kennedy pathway. Other LPLATs of both the AGPAT and the membrane bound O-acyltransferase (MBOAT) families further modify the fatty chain compositions of membrane glycerophospholipids in the remodeling pathway known as the Lands' cycle. The LPLATs functioning in these pathways possess unique characteristics in terms of their biochemical activities, regulation of expressions, and functions in various biological contexts. Essential physiological functions for LPLATs have been revealed in studies using gene-deficient mice, and important roles for several enzymes are also indicated in human diseases where their mutation or dysregulation causes or contributes to the pathological condition. Now several LPLATs are emerging as attractive therapeutic targets, and further understanding of the mechanisms underlying their physiological and pathological roles will aid in the development of novel therapies to treat several diseases that involve altered glycerophospholipid metabolism.
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Affiliation(s)
- William J Valentine
- Department of Lipid Signaling, National Center for Global Health and Medicine, Tokyo, Japan. .,Department of Molecular Therapy, National Center of Neurology and Psychiatry, Tokyo, Japan.
| | | | - Shota Yamamoto
- Department of Lipid Signaling, National Center for Global Health and Medicine, Tokyo, Japan
| | - Hideo Shindou
- Department of Lipid Signaling, National Center for Global Health and Medicine, Tokyo, Japan. .,Department of Lipid Science, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan. .,Japan Agency for Medical Research and Development, Tokyo, Japan.
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Abstract
The cause of insulin resistance in obesity and type 2 diabetes mellitus (T2DM) is not limited to impaired insulin signalling but also involves the complex interplay of multiple metabolic pathways. The analysis of large data sets generated by metabolomics and lipidomics has shed new light on the roles of metabolites such as lipids, amino acids and bile acids in modulating insulin sensitivity. Metabolites can regulate insulin sensitivity directly by modulating components of the insulin signalling pathway, such as insulin receptor substrates (IRSs) and AKT, and indirectly by altering the flux of substrates through multiple metabolic pathways, including lipogenesis, lipid oxidation, protein synthesis and degradation and hepatic gluconeogenesis. Moreover, the post-translational modification of proteins by metabolites and lipids, including acetylation and palmitoylation, can alter protein function. Furthermore, the role of the microbiota in regulating substrate metabolism and insulin sensitivity is unfolding. In this Review, we discuss the emerging roles of metabolites in the pathogenesis of insulin resistance and T2DM. A comprehensive understanding of the metabolic adaptations involved in insulin resistance may enable the identification of novel targets for improving insulin sensitivity and preventing, and treating, T2DM.
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Therapeutic targeting of lipid synthesis metabolism for selective elimination of cancer stem cells. Arch Pharm Res 2018; 42:25-39. [PMID: 30536027 DOI: 10.1007/s12272-018-1098-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 12/01/2018] [Indexed: 02/06/2023]
Abstract
Cancer stem cells (CSCs) are believed to have an essential role in tumor resistance and metastasis; however, no therapeutic strategy for the selective elimination of CSCs has been established. Recently, several studies have shown that the metabolic regulation for ATP synthesis and biological building block generation in CSCs are different from that in bulk cancer cells and rather similar to that in normal tissue stem cells. To take advantage of this difference for CSC elimination therapy, many studies have tested the effect of blocking these metabolism. Two specific processes for lipid biosynthesis, i.e., fatty acid unsaturation and cholesterol biosynthesis, have been shown to be very effective and selective for CSC targets. In this review, lipid metabolism specific to CSCs are summarized. In addition, how monounsaturated fatty acid and cholesterol synthesis may contribute to CSC maintenance are discussed. Specifically, the molecular mechanism required for lipid synthesis and essential for stem cell biology is highlighted. The limit and preview of the lipid metabolism targeting for CSCs are also discussed.
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Ying Z, Byun HR, Meng Q, Noble E, Zhang G, Yang X, Gomez-Pinilla F. Biglycan gene connects metabolic dysfunction with brain disorder. Biochim Biophys Acta Mol Basis Dis 2018; 1864:3679-3687. [PMID: 30291886 PMCID: PMC6239930 DOI: 10.1016/j.bbadis.2018.10.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 09/11/2018] [Accepted: 10/01/2018] [Indexed: 12/30/2022]
Abstract
Dietary fructose is a major contributor to the epidemic of diabetes and obesity, and it is an excellent model to study metabolic syndrome. Based on previous studies that Bgn gene occupies a central position in a network of genes in the brain in response to fructose consumption, we assessed the capacity of Bgn to modulate the action of fructose on brain and body. We exposed male biglycan knockout mice (Bgn0/-) to fructose for 7 weeks, and results showed that Bgn0/- mice compensated for a decrement in learning and memory performance when exposed to fructose. These results were consistent with an attenuation of the action of fructose on hippocampal CREB levels. Fructose also reduced the levels of CREB and BDNF in primary hippocampal neuronal cultures. Bgn siRNA treatment abolished these effects of fructose on CREB and BDNF levels, in conjunction with a reduction in a fructose-related increase in Bgn protein. In addition, fructose consumption perturbed the systemic metabolism of glucose and lipids, that were also altered in the Bgn0/ mice. Transcriptomic profiling of hypothalamus, hippocampus, and liver supported the regulatory action of Bgn on key molecular pathways involved in metabolism, immune response, and neuronal plasticity. Overall results underscore the tissue-specific role of the extracellular matrix in the regulation of metabolism and brain function, and support Bgn as a key modulator for the impact of fructose across body and brain.
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Affiliation(s)
- Zhe Ying
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Hyae Ran Byun
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Qingying Meng
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Emily Noble
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Guanglin Zhang
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Xia Yang
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, California 90095, USA.
| | - Fernando Gomez-Pinilla
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, California 90095, USA; Department of Neurosurgery, UCLA Brain Injury Research Center, University of California, Los Angeles, Los Angeles, California 90095, USA.
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11
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Hanning AR, Wang X, Hashemi Z, Wan S, England A, Jacobs RL, Chan CB. Both low- and regular-fat cheeses mediate improved insulin sensitivity and modulate serum phospholipid profiles in insulin-resistant rats. J Nutr Biochem 2018; 64:144-151. [PMID: 30502658 DOI: 10.1016/j.jnutbio.2018.10.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 10/03/2018] [Accepted: 10/29/2018] [Indexed: 12/18/2022]
Abstract
Dietary recommendations for cheese usually promote low (LOW)- over regular (REG)-fat versions due to the saturated fat. Conversely, epidemiological evidence shows that cheese consumption associates with reduced risk of type 2 diabetes. To investigate how cheese influences diabetes-related outcomes, a feeding trial comparing LOW and REG cheese was conducted in high-fat, lard-based diet (HFD)-fed insulin-resistant rats followed by evaluation of potential mechanisms. After 4 weeks of HFD, LOW or REG was added at 7 and 10 g/100 g diet, respectively, for another 8 weeks. Following either an oral glucose or insulin tolerance test to assess glucoregulation, rats were euthanized and serum was collected for metabolomic and lipid analyses. Hepatic tissue was used to measure glucoregulatory enzymes and lipid content. Both LOW and REG improved insulin sensitivity without effect on oral glucose tolerance, insulin secretion or body weight. Serum metabolomics identified 33 metabolites of interest, with 21 being phosphatidylcholines (PCs) or lysophosphatidylcholines (LPCs). HFD rats had significantly reduced LPC C16:1, C17:0, C18:1, C20:3 and C24:0, and these effects were normalized by LOW or REG cheese. Fourteen PC species were lowest in the HFD group and normalized by cheese feeding. Serum choline was elevated sevenfold in HFD- but not cheese-fed rats compared with rats fed low-fat diet. Liver triglyceride was elevated by LOW feeding. In conclusion, inclusion of both LOW and REG cheeses in the diet of insulin-resistant rats improves in vivo glucoregulation. This is associated with altered phospholipid metabolism, including cheese-mediated normalization of species that are decreased by high-fat feeding.
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Affiliation(s)
- Anik Rz Hanning
- Department of Agriculture, Food and Nutritional Science, University of Alberta, 6-002 Li Ka Shing Centre, Edmonton, AB, Canada T6G 1E3.
| | - Xiaofeng Wang
- Department of Agriculture, Food and Nutritional Science, University of Alberta, 6-002 Li Ka Shing Centre, Edmonton, AB, Canada T6G 1E3.
| | - Zohre Hashemi
- Department of Agriculture, Food and Nutritional Science, University of Alberta, 6-002 Li Ka Shing Centre, Edmonton, AB, Canada T6G 1E3.
| | - Sereana Wan
- Department of Agriculture, Food and Nutritional Science, University of Alberta, 6-002 Li Ka Shing Centre, Edmonton, AB, Canada T6G 1E3.
| | - Alexandra England
- Department of Physiology, University of Alberta, 7-53 Medical Sciences Building, Edmonton, AB, Canada T6G 2H7.
| | - René L Jacobs
- Department of Agriculture, Food and Nutritional Science, University of Alberta, 6-002 Li Ka Shing Centre, Edmonton, AB, Canada T6G 1E3; Department of Biochemistry, University of Alberta, 4-74 Medical Sciences Building, Edmonton, AB, Canada T6G 2R3.
| | - Catherine B Chan
- Department of Agriculture, Food and Nutritional Science, University of Alberta, 6-002 Li Ka Shing Centre, Edmonton, AB, Canada T6G 1E3; Department of Physiology, University of Alberta, 7-53 Medical Sciences Building, Edmonton, AB, Canada T6G 2H7.
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Abstract
Phospholipids are major constituents of biological membranes. The fatty acyl chain composition of phospholipids determines the biophysical properties of membranes and thereby affects their impact on biological processes. The composition of fatty acyl chains is also actively regulated through a deacylation and reacylation pathway called Lands' cycle. Recent studies of mouse genetic models have demonstrated that lysophosphatidylcholine acyltransferases (LPCATs), which catalyze the incorporation of fatty acyl chains into the sn-2 site of phosphatidylcholine, play important roles in pathophysiology. Two LPCAT family members, LPCAT1 and LPCAT3, have been particularly well studied. LPCAT1 is crucial for proper lung function due to its role in pulmonary surfactant biosynthesis. LPCAT3 maintains systemic lipid homeostasis by regulating lipid absorption in intestine, lipoprotein secretion, and de novo lipogenesis in liver. Mounting evidence also suggests that changes in LPCAT activity may be potentially involved in pathological conditions, including nonalcoholic fatty liver disease, atherosclerosis, viral infections, and cancer. Pharmacological manipulation of LPCAT activity and membrane phospholipid composition may provide new therapeutic options for these conditions.
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Affiliation(s)
- Bo Wang
- Department of Pathology and Laboratory Medicine, Molecular Biology Institute, David Geffen School of Medicine, University of California, Los Angeles, California 90272, USA;
| | - Peter Tontonoz
- Department of Pathology and Laboratory Medicine, Molecular Biology Institute, David Geffen School of Medicine, University of California, Los Angeles, California 90272, USA;
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Paalvast Y, de Boer JF, Groen AK. Developments in intestinal cholesterol transport and triglyceride absorption. Curr Opin Lipidol 2017; 28:248-254. [PMID: 28338522 DOI: 10.1097/mol.0000000000000415] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE OF REVIEW To discuss recent advances in research focused on intestinal lipid handling. RECENT FINDINGS An important strategy in reducing atherosclerosis and risk of cardiovascular events is to increase the rate of reverse cholesterol transport, including its final step; cholesterol excretion from the body. The rate of removal is determined by a complex interplay between the factors involved in regulation of intestinal cholesterol absorption. One of these factors is a process known as transintestinal cholesterol excretion. This pathway comprises transport of cholesterol directly from the blood, through the enterocyte, into the intestinal lumen. In humans, this pathway accounts for 35% of cholesterol excretion in the feces. Mechanistic studies in mice revealed that, activation of the bile acid receptor farnesoid X receptor increases cholesterol removal via the transintestinal cholesterol excretion pathway as well as decreases plasma cholesterol and triglyceride providing an interesting target for treatment of dyslipidemia in humans. The physical chemical properties of bile acids are under control of farnesoid X receptor and determine intestinal cholesterol and triglyceride solubilization as well as absorption, providing a direct link between these two important factors in the pathogenesis of cardiovascular disease. Besides bile acids, intestinal phospholipids are important for luminal lipid solubilization. Interestingly, phospholipid remodeling through LPCAT3 was shown to be pivotal for uptake of fatty acids by enterocytes, which may provide a mechanistic handle for therapeutic intervention. SUMMARY The importance of the intestine in control of cholesterol and triglyceride homeostasis is increasingly recognized. Recently, novel factors involved in regulation of cholesterol excretion and intestinal triglyceride and fatty acid uptake have been reported and are discussed in this short review.
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Affiliation(s)
- Yared Paalvast
- aDepartment of Pediatrics bDepartment of Laboratory Medicine, University of Groningen, University Medical Center Groningen cDepartment of Vascular Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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Singh AB, Liu J. Identification of Hepatic Lysophosphatidylcholine Acyltransferase 3 as a Novel Target Gene Regulated by Peroxisome Proliferator-activated Receptor δ. J Biol Chem 2016; 292:884-897. [PMID: 27913621 DOI: 10.1074/jbc.m116.743575] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 11/29/2016] [Indexed: 12/31/2022] Open
Abstract
Peroxisome proliferator-activated receptor δ (PPARδ) regulates many genes involved in lipid metabolism. Hepatic lysophosphatidylcholine acyltransferase 3 (LPCAT3) has critical functions in triglycerides transport and endoplasmic reticulum stress response due to its unique ability to catalyze the incorporation of polyunsaturated fatty acids into phospholipids. Previous studies identified liver X receptor as the transcription factor controlling LPCAT3 expression in mouse liver tissue. Here we show that the hepatic LPCAT3 gene is transcriptionally regulated by PPARδ. Adenovirus-mediated knockdown of PPARδ in cultured hepatic cells and liver tissue reduced LPCAT3 mRNA levels, and exogenous overexpression of PPARδ increased LPCAT3 mRNA expression. Activation of PPARδ in HepG2, Huh7, and Hepa 1-6 cells with its specific agonists increased LPCAT3 mRNA levels in all three hepatic cell lines. Through conducting sequence analysis, LPCAT3 promoter assays, and direct DNA binding assays, we have mapped the functional PPAR-responsive element to a proximal region from -135 to -123 of the LPCAT3 promoter that plays an essential role in mediating PPARδ-induced transactivation of the LPCAT3 gene. Finally, we have provided in vivo evidence showing that activation of PPARδ by agonist L165041 in mice increased hepatic LPCAT3 mRNA abundance and LPCAT enzymatic activity, which is associated with increased incorporations of arachidonate into liver phosphatidylcholine and phosphatidylethanolamine. Furthermore, transient liver-specific knockdown of LPCAT3 in mice affected PPARδ-mediated activation of several hepatic genes involving in FA metabolism. Altogether, our new findings identify LPCAT3 as a direct PPARδ target gene and suggest a novel function of PPARδ in regulation of phospholipid metabolism through LPCAT3.
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Affiliation(s)
- Amar Bahadur Singh
- From the Department of Veterans Affairs Palo Alto Health Care System, Palo Alto, California 94304
| | - Jingwen Liu
- From the Department of Veterans Affairs Palo Alto Health Care System, Palo Alto, California 94304
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