1
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McQueen P, Molina D, Pinos I, Krug S, Taylor AJ, LaFrano MR, Kane MA, Amengual J. Finasteride delays atherosclerosis progression in mice and is associated with a reduction in plasma cholesterol in men. J Lipid Res 2024; 65:100507. [PMID: 38272355 PMCID: PMC10899056 DOI: 10.1016/j.jlr.2024.100507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 01/08/2024] [Accepted: 01/10/2024] [Indexed: 01/27/2024] Open
Abstract
Finasteride is commonly prescribed to treat benign prostate hyperplasia and male-pattern baldness in cis men and, more recently, trans individuals. However, the effect of finasteride on cardiovascular disease remains elusive. We evaluated the role of finasteride on atherosclerosis using low-density lipoprotein (LDL) receptor-deficient (Ldlr-/-) mice. Next, we examined the relevance to humans by analyzing the data deposited between 2009 and 2016 in the National Health and Nutrition Examination Survey. We show that finasteride reduces total plasma cholesterol and delays the development of atherosclerosis in Ldlr-/- mice. Finasteride reduced monocytosis, monocyte recruitment to the lesion, macrophage lesion content, and necrotic core area, the latter of which is an indicator of plaque vulnerability in humans. RNA sequencing analysis revealed a downregulation of inflammatory pathways and an upregulation of bile acid metabolism, oxidative phosphorylation, and cholesterol pathways in the liver of mice taking finasteride. Men reporting the use of finasteride showed lower plasma levels of cholesterol and LDL-cholesterol than those not taking the drug. Our data unveil finasteride as a potential treatment to delay cardiovascular disease in people by improving the plasma lipid profile.
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Affiliation(s)
- Patrick McQueen
- Division of Nutritional Sciences, University of Illinois Urbana Champaign, Urbana, IL, USA
| | - Donald Molina
- Department of Food Science and Human Nutrition, University of Illinois Urbana Champaign, Urbana, IL, USA
| | - Ivan Pinos
- Division of Nutritional Sciences, University of Illinois Urbana Champaign, Urbana, IL, USA
| | - Samuel Krug
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD, USA
| | - Anna J Taylor
- Carver Metabolomics Core, Roy J. Carver Biotechnology Center, University of Illinois Urbana Champaign, Urbana, IL, USA
| | - Michael R LaFrano
- Carver Metabolomics Core, Roy J. Carver Biotechnology Center, University of Illinois Urbana Champaign, Urbana, IL, USA
| | - Maureen A Kane
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD, USA
| | - Jaume Amengual
- Division of Nutritional Sciences, University of Illinois Urbana Champaign, Urbana, IL, USA; Department of Food Science and Human Nutrition, University of Illinois Urbana Champaign, Urbana, IL, USA.
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2
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Kounatidis D, Vallianou NG, Poulaki A, Evangelopoulos A, Panagopoulos F, Stratigou T, Geladari E, Karampela I, Dalamaga M. ApoB100 and Atherosclerosis: What's New in the 21st Century? Metabolites 2024; 14:123. [PMID: 38393015 PMCID: PMC10890411 DOI: 10.3390/metabo14020123] [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: 01/04/2024] [Revised: 02/08/2024] [Accepted: 02/09/2024] [Indexed: 02/25/2024] Open
Abstract
ApoB is the main protein of triglyceride-rich lipoproteins and is further divided into ApoB48 in the intestine and ApoB100 in the liver. Very low-density lipoprotein (VLDL) is produced by the liver, contains ApoB100, and is metabolized into its remnants, intermediate-density lipoprotein (IDL) and low-density lipoprotein (LDL). ApoB100 has been suggested to play a crucial role in the formation of the atherogenic plaque. Apart from being a biomarker of atherosclerosis, ApoB100 seems to be implicated in the inflammatory process of atherosclerosis per se. In this review, we will focus on the structure, the metabolism, and the function of ApoB100, as well as its role as a predictor biomarker of cardiovascular risk. Moreover, we will elaborate upon the molecular mechanisms regarding the pathophysiology of atherosclerosis, and we will discuss the disorders associated with the APOB gene mutations, and the potential role of various drugs as therapeutic targets.
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Affiliation(s)
- Dimitris Kounatidis
- Second Department of Internal Medicine, Hippokration General Hospital, School of Medicine, National and Kapodistrian University of Athens, 11527 Athens, Greece
| | - Natalia G Vallianou
- Department of Internal Medicine, Evangelismos General Hospital, 10676 Athens, Greece
| | - Aikaterini Poulaki
- Hematology Unit, Second Department of Internal Medicine, School of Medicine, National and Kapodistrian University of Athens, 11527 Athens, Greece
| | | | - Fotis Panagopoulos
- Department of Internal Medicine, Evangelismos General Hospital, 10676 Athens, Greece
| | - Theodora Stratigou
- Department of Endocrinology and Metabolism, Evangelismos General Hospital, 10676 Athens, Greece
| | - Eleni Geladari
- Department of Internal Medicine, Evangelismos General Hospital, 10676 Athens, Greece
| | - Irene Karampela
- Second Department of Critical Care, Attikon General University Hospital, Medical School, National and Kapodistrian University of Athens, 12462 Athens, Greece
| | - Maria Dalamaga
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece
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3
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Burks KH, Xie Y, Gildea M, Jung IH, Mukherjee S, Lee P, Pudupakkam U, Wagoner R, Patel V, Santana K, Alisio A, Goldberg IJ, Finck BN, Fisher EA, Davidson NO, Stitziel NO. ANGPTL3 deficiency impairs lipoprotein production and produces adaptive changes in hepatic lipid metabolism. J Lipid Res 2024; 65:100500. [PMID: 38219820 PMCID: PMC10875267 DOI: 10.1016/j.jlr.2024.100500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 12/22/2023] [Accepted: 12/23/2023] [Indexed: 01/16/2024] Open
Abstract
Angiopoietin-like protein 3 (ANGPTL3) is a hepatically secreted protein and therapeutic target for reducing plasma triglyceride-rich lipoproteins and low-density lipoprotein (LDL) cholesterol. Although ANGPTL3 modulates the metabolism of circulating lipoproteins, its role in triglyceride-rich lipoprotein assembly and secretion remains unknown. CRISPR-associated protein 9 (CRISPR/Cas9) was used to target ANGPTL3 in HepG2 cells (ANGPTL3-/-) whereupon we observed ∼50% reduction of apolipoprotein B100 (ApoB100) secretion, accompanied by an increase in ApoB100 early presecretory degradation via a predominantly lysosomal mechanism. Despite defective particle secretion in ANGPTL3-/- cells, targeted lipidomic analysis did not reveal neutral lipid accumulation in ANGPTL3-/- cells; rather ANGPTL3-/- cells demonstrated decreased secretion of newly synthesized triglycerides and increased fatty acid oxidation. Furthermore, RNA sequencing demonstrated significantly altered expression of key lipid metabolism genes, including targets of peroxisome proliferator-activated receptor α, consistent with decreased lipid anabolism and increased lipid catabolism. In contrast, CRISPR/Cas9 LDL receptor (LDLR) deletion in ANGPTL3-/- cells did not result in a secretion defect at baseline, but proteasomal inhibition strongly induced compensatory late presecretory degradation of ApoB100 and impaired its secretion. Additionally, these ANGPTL3-/-;LDLR-/- cells rescued the deficient LDL clearance of LDLR-/- cells. In summary, ANGPTL3 deficiency in the presence of functional LDLR leads to the production of fewer lipoprotein particles due to early presecretory defects in particle assembly that are associated with adaptive changes in intrahepatic lipid metabolism. In contrast, when LDLR is absent, ANGPTL3 deficiency is associated with late presecretory regulation of ApoB100 degradation without impaired secretion. Our findings therefore suggest an unanticipated intrahepatic role for ANGPTL3, whose function varies with LDLR status.
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Affiliation(s)
- Kendall H Burks
- Division of Cardiology, Department of Medicine, Center for Cardiovascular Research, Washington University School of Medicine, Saint Louis, MO, USA
| | - Yan Xie
- Division of Gastroenterology, Department of Medicine, Washington University School of Medicine, Saint Louis, MO, USA
| | - Michael Gildea
- Division of Cardiology, Department of Medicine, New York University Grossman School of Medicine, New York, NY, USA
| | - In-Hyuk Jung
- Division of Cardiology, Department of Medicine, Center for Cardiovascular Research, Washington University School of Medicine, Saint Louis, MO, USA
| | - Sandip Mukherjee
- Division of Nutritional Science and Obesity Medicine, Department of Medicine, Center for Human Nutrition, Washington University School of Medicine, Saint Louis, MO, USA
| | - Paul Lee
- Division of Cardiology, Department of Medicine, Center for Cardiovascular Research, Washington University School of Medicine, Saint Louis, MO, USA
| | - Upasana Pudupakkam
- Division of Cardiology, Department of Medicine, Center for Cardiovascular Research, Washington University School of Medicine, Saint Louis, MO, USA
| | - Ryan Wagoner
- Division of Cardiology, Department of Medicine, Center for Cardiovascular Research, Washington University School of Medicine, Saint Louis, MO, USA
| | - Ved Patel
- Division of Cardiology, Department of Medicine, Center for Cardiovascular Research, Washington University School of Medicine, Saint Louis, MO, USA
| | - Katherine Santana
- Division of Cardiology, Department of Medicine, Center for Cardiovascular Research, Washington University School of Medicine, Saint Louis, MO, USA
| | - Arturo Alisio
- Division of Cardiology, Department of Medicine, Center for Cardiovascular Research, Washington University School of Medicine, Saint Louis, MO, USA
| | - Ira J Goldberg
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, New York University Grossman School of Medicine, New York, NY, USA
| | - Brian N Finck
- Division of Nutritional Science and Obesity Medicine, Department of Medicine, Center for Human Nutrition, Washington University School of Medicine, Saint Louis, MO, USA
| | - Edward A Fisher
- Division of Cardiology, Department of Medicine, New York University Grossman School of Medicine, New York, NY, USA
| | - Nicholas O Davidson
- Division of Gastroenterology, Department of Medicine, Washington University School of Medicine, Saint Louis, MO, USA.
| | - Nathan O Stitziel
- Division of Cardiology, Department of Medicine, Center for Cardiovascular Research, Washington University School of Medicine, Saint Louis, MO, USA; Department of Genetics, Washington University School of Medicine, Saint Louis, MO, USA.
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4
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Sadeghi A, Niknam M, Momeni-Moghaddam MA, Shabani M, Aria H, Bastin A, Teimouri M, Meshkani R, Akbari H. Crosstalk between autophagy and insulin resistance: evidence from different tissues. Eur J Med Res 2023; 28:456. [PMID: 37876013 PMCID: PMC10599071 DOI: 10.1186/s40001-023-01424-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 10/03/2023] [Indexed: 10/26/2023] Open
Abstract
Insulin is a critical hormone that promotes energy storage in various tissues, as well as anabolic functions. Insulin resistance significantly reduces these responses, resulting in pathological conditions, such as obesity and type 2 diabetes mellitus (T2DM). The management of insulin resistance requires better knowledge of its pathophysiological mechanisms to prevent secondary complications, such as cardiovascular diseases (CVDs). Recent evidence regarding the etiological mechanisms behind insulin resistance emphasizes the role of energy imbalance and neurohormonal dysregulation, both of which are closely regulated by autophagy. Autophagy is a conserved process that maintains homeostasis in cells. Accordingly, autophagy abnormalities have been linked to a variety of metabolic disorders, including insulin resistance, T2DM, obesity, and CVDs. Thus, there may be a link between autophagy and insulin resistance. Therefore, the interaction between autophagy and insulin function will be examined in this review, particularly in insulin-responsive tissues, such as adipose tissue, liver, and skeletal muscle.
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Affiliation(s)
- Asie Sadeghi
- Student Research Committee, Kerman University of Medical Sciences, Kerman, Iran
- Department of Clinical Biochemistry, Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Maryam Niknam
- Department of Biochemistry, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | | | - Maryam Shabani
- Department of Clinical Biochemistry, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Hamid Aria
- Noncommunicable Diseases Research Center, Fasa University of Medical Sciences, Fasa, Iran
- Department of Immunology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Alireza Bastin
- Clinical Research Development Center "The Persian Gulf Martyrs" Hospital, Bushehr University of Medical Sciences, Bushehr, Iran
| | - Maryam Teimouri
- Department of Biochemistry, School of Allied Medical Sciences, Shahroud University of Medical Sciences, Shahroud, Iran
| | - Reza Meshkani
- Department of Clinical Biochemistry, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Hamed Akbari
- Student Research Committee, Kerman University of Medical Sciences, Kerman, Iran.
- Department of Clinical Biochemistry, Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran.
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5
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Yanai H, Adachi H, Hakoshima M, Iida S, Katsuyama H. Metabolic-Dysfunction-Associated Steatotic Liver Disease-Its Pathophysiology, Association with Atherosclerosis and Cardiovascular Disease, and Treatments. Int J Mol Sci 2023; 24:15473. [PMID: 37895151 PMCID: PMC10607514 DOI: 10.3390/ijms242015473] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/13/2023] [Accepted: 10/17/2023] [Indexed: 10/29/2023] Open
Abstract
Metabolic-dysfunction-associated steatotic liver disease (MASLD) is a chronic liver disease that affects more than a quarter of the global population and whose prevalence is increasing worldwide due to the pandemic of obesity. Obesity, impaired glucose metabolism, high blood pressure and atherogenic dyslipidemia are risk factors for MASLD. Therefore, insulin resistance may be closely associated with the development and progression of MASLD. Hepatic entry of increased fatty acids released from adipose tissue, increase in fatty acid synthesis and reduced fatty acid oxidation in the liver and hepatic overproduction of triglyceride-rich lipoproteins may induce the development of MASLD. Since insulin resistance also induces atherosclerosis, the leading cause for death in MASLD patients is cardiovascular disease. Considering that the development of cardiovascular diseases determines the prognosis of MASLD patients, the therapeutic interventions for MASLD should reduce body weight and improve coronary risk factors, in addition to an improving in liver function. Lifestyle modifications, such as improved diet and increased exercise, and surgical interventions, such as bariatric surgery and intragastric balloons, have shown to improve MASLD by reducing body weight. Sodium glucose cotransporter 2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor agonists (GLP-1RAs) have been shown to improve coronary risk factors and to suppress the occurrence of cardiovascular diseases. Both SGLT2i and GLP-1 have been reported to improve liver enzymes, hepatic steatosis and fibrosis. We recently reported that the selective peroxisome proliferator-activated receptor-alpha (PPARα) modulator pemafibrate improved liver function. PPARα agonists have multiple anti-atherogenic properties. Here, we consider the pathophysiology of MASLD and the mechanisms of action of such drugs and whether such drugs and the combination therapy of such drugs could be the treatments for MASLD.
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Affiliation(s)
- Hidekatsu Yanai
- Department of Diabetes, Endocrinology and Metabolism, National Center for Global Health and Medicine, Kohnodai Hospital, 1-7-1 Kohnodai, Ichikawa 272-8516, Japan; (H.A.); (M.H.); (S.I.); (H.K.)
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6
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Dai W, Zhang H, Lund H, Zhang Z, Castleberry M, Rodriguez M, Kuriakose G, Gupta S, Lewandowska M, Powers HR, Valmiki S, Zhu J, Shapiro AD, Hussain MM, López JA, Sorci-Thomas MG, Silverstein RL, Ginsberg HN, Sahoo D, Tabas I, Zheng Z. Intracellular tPA-PAI-1 interaction determines VLDL assembly in hepatocytes. Science 2023; 381:eadh5207. [PMID: 37651538 PMCID: PMC10697821 DOI: 10.1126/science.adh5207] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 07/13/2023] [Indexed: 09/02/2023]
Abstract
Apolipoprotein B (apoB)-lipoproteins initiate and promote atherosclerotic cardiovascular disease. Plasma tissue plasminogen activator (tPA) activity is negatively associated with atherogenic apoB-lipoprotein cholesterol levels in humans, but the mechanisms are unknown. We found that tPA, partially through the lysine-binding site on its Kringle 2 domain, binds to the N terminus of apoB, blocking the interaction between apoB and microsomal triglyceride transfer protein (MTP) in hepatocytes, thereby reducing very-low-density lipoprotein (VLDL) assembly and plasma apoB-lipoprotein cholesterol levels. Plasminogen activator inhibitor 1 (PAI-1) sequesters tPA away from apoB and increases VLDL assembly. Humans with PAI-1 deficiency have smaller VLDL particles and lower plasma levels of apoB-lipoprotein cholesterol. These results suggest a mechanism that fine-tunes VLDL assembly by intracellular interactions among tPA, PAI-1, and apoB in hepatocytes.
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Affiliation(s)
- Wen Dai
- Versiti Blood Research Institute, Milwaukee, WI 53226, USA
| | - Heng Zhang
- Versiti Blood Research Institute, Milwaukee, WI 53226, USA
| | - Hayley Lund
- Department of Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Ziyu Zhang
- Versiti Blood Research Institute, Milwaukee, WI 53226, USA
| | | | - Maya Rodriguez
- Versiti Blood Research Institute, Milwaukee, WI 53226, USA
- College of Arts and Sciences, Marquette University, Milwaukee, WI 53233, USA
| | - George Kuriakose
- Department of Medicine, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Sweta Gupta
- Indiana Hemophilia and Thrombosis Center, Indianapolis, IN 46260, USA
| | | | - Hayley R. Powers
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Swati Valmiki
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
- Department of Foundations of Medicine, NYU Long Island School of Medicine, Mineola, NY 11501, USA
| | - Jieqing Zhu
- Versiti Blood Research Institute, Milwaukee, WI 53226, USA
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Amy D. Shapiro
- Indiana Hemophilia and Thrombosis Center, Indianapolis, IN 46260, USA
| | - M. Mahmood Hussain
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
- Department of Foundations of Medicine, NYU Long Island School of Medicine, Mineola, NY 11501, USA
| | - José A. López
- Bloodworks Research Institute, Seattle, WA 98102, USA
- Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Mary G. Sorci-Thomas
- Department of Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Roy L. Silverstein
- Versiti Blood Research Institute, Milwaukee, WI 53226, USA
- Department of Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Henry N. Ginsberg
- Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA
| | - Daisy Sahoo
- Department of Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Ira Tabas
- Department of Medicine, Columbia University Irving Medical Center, New York, NY 10032, USA
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Ze Zheng
- Versiti Blood Research Institute, Milwaukee, WI 53226, USA
- Department of Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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7
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Vatandaslar H, Garzia A, Meyer C, Godbersen S, Brandt LTL, Griesbach E, Chao JA, Tuschl T, Stoffel M. In vivo PAR-CLIP (viP-CLIP) of liver TIAL1 unveils targets regulating cholesterol synthesis and secretion. Nat Commun 2023; 14:3386. [PMID: 37296170 PMCID: PMC10256721 DOI: 10.1038/s41467-023-39135-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Accepted: 05/31/2023] [Indexed: 06/12/2023] Open
Abstract
System-wide cross-linking and immunoprecipitation (CLIP) approaches have unveiled regulatory mechanisms of RNA-binding proteins (RBPs) mainly in cultured cells due to limitations in the cross-linking efficiency of tissues. Here, we describe viP-CLIP (in vivo PAR-CLIP), a method capable of identifying RBP targets in mammalian tissues, thereby facilitating the functional analysis of RBP-regulatory networks in vivo. We applied viP-CLIP to mouse livers and identified Insig2 and ApoB as prominent TIAL1 target transcripts, indicating an important role of TIAL1 in cholesterol synthesis and secretion. The functional relevance of these targets was confirmed by showing that TIAL1 influences their translation in hepatocytes. Mutant Tial1 mice exhibit altered cholesterol synthesis, APOB secretion and plasma cholesterol levels. Our results demonstrate that viP-CLIP can identify physiologically relevant RBP targets by finding a factor implicated in the negative feedback regulation of cholesterol biosynthesis.
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Affiliation(s)
- Hasan Vatandaslar
- Institute of Molecular Health Sciences, ETH Zurich, Otto-Stern-Weg 7, 8093, Zürich, Switzerland
| | - Aitor Garzia
- Laboratory of RNA Molecular Biology, The Rockefeller University, 1230 York Avenue, New York, NY, 10021, USA
| | - Cindy Meyer
- Laboratory of RNA Molecular Biology, The Rockefeller University, 1230 York Avenue, New York, NY, 10021, USA
| | - Svenja Godbersen
- Institute of Molecular Health Sciences, ETH Zurich, Otto-Stern-Weg 7, 8093, Zürich, Switzerland
| | - Laura T L Brandt
- Institute of Molecular Health Sciences, ETH Zurich, Otto-Stern-Weg 7, 8093, Zürich, Switzerland
| | - Esther Griesbach
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058, Basel, Switzerland
| | - Jeffrey A Chao
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058, Basel, Switzerland
| | - Thomas Tuschl
- Laboratory of RNA Molecular Biology, The Rockefeller University, 1230 York Avenue, New York, NY, 10021, USA
| | - Markus Stoffel
- Institute of Molecular Health Sciences, ETH Zurich, Otto-Stern-Weg 7, 8093, Zürich, Switzerland.
- Medical Faculty, University of Zürich, 8091, Zürich, Switzerland.
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8
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Huang JK, Lee HC. Emerging Evidence of Pathological Roles of Very-Low-Density Lipoprotein (VLDL). Int J Mol Sci 2022; 23:ijms23084300. [PMID: 35457118 PMCID: PMC9031540 DOI: 10.3390/ijms23084300] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Revised: 04/10/2022] [Accepted: 04/11/2022] [Indexed: 12/18/2022] Open
Abstract
Embraced with apolipoproteins (Apo) B and Apo E, triglyceride-enriched very-low-density lipoprotein (VLDL) is secreted by the liver into circulation, mainly during post-meal hours. Here, we present a brief review of the physiological role of VLDL and a systemic review of the emerging evidence supporting its pathological roles. VLDL promotes atherosclerosis in metabolic syndrome (MetS). VLDL isolated from subjects with MetS exhibits cytotoxicity to atrial myocytes, induces atrial myopathy, and promotes vulnerability to atrial fibrillation. VLDL levels are affected by a number of endocrinological disorders and can be increased by therapeutic supplementation with cortisol, growth hormone, progesterone, and estrogen. VLDL promotes aldosterone secretion, which contributes to hypertension. VLDL induces neuroinflammation, leading to cognitive dysfunction. VLDL levels are also correlated with chronic kidney disease, autoimmune disorders, and some dermatological diseases. The extra-hepatic secretion of VLDL derived from intestinal dysbiosis is suggested to be harmful. Emerging evidence suggests disturbed VLDL metabolism in sleep disorders and in cancer development and progression. In addition to VLDL, the VLDL receptor (VLDLR) may affect both VLDL metabolism and carcinogenesis. Overall, emerging evidence supports the pathological roles of VLDL in multi-organ diseases. To better understand the fundamental mechanisms of how VLDL promotes disease development, elucidation of the quality control of VLDL and of the regulation and signaling of VLDLR should be indispensable. With this, successful VLDL-targeted therapies can be discovered in the future.
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Affiliation(s)
- Jih-Kai Huang
- Department of General Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan;
| | - Hsiang-Chun Lee
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Department of Internal Medicine, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Lipid Science and Aging Research Center, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung 80708, Taiwan
- Graduate Institute of Animal Vaccine Technology, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
- Correspondence: ; Tel.: +886-7-3121101 (ext. 7741)
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9
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Schwabl S, Teis D. Protein quality control at the Golgi. Curr Opin Cell Biol 2022; 75:102074. [PMID: 35364487 DOI: 10.1016/j.ceb.2022.02.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/14/2022] [Accepted: 02/17/2022] [Indexed: 11/28/2022]
Abstract
The majority of the proteome in eukaryotic cells is targeted to organelles. To maintain protein homeostasis (proteostasis), distinct protein quality control (PQC) machineries operate on organelles, where they detect misfolded proteins, orphaned and mis-localized proteins and selectively target these proteins into different ubiquitin-dependent or -independent degradation pathways. Thereby, PQC prevents proteotoxic effects that would disrupt organelle integrity and cause cellular damage that leads to diseases. Here, we will discuss emerging mechanisms for PQC machineries at the Golgi apparatus, the central station for the sorting and the modification of proteins that traffic to the endo-lysosomal system, or along the secretory pathway to the PM and to the extracellular space. We will focus on Golgi PQC pathways that (1) retrieve misfolded and orphaned proteins from the Golgi back to the endoplasmic reticulum, (2) extract these proteins from Golgi membranes for proteasomal degradation, (3) or selectively target these proteins to lysosomes for degradation.
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Affiliation(s)
- Sinead Schwabl
- Institute for Cell Biology, Biocenter, Medical University of Innsbruck, Austria
| | - David Teis
- Institute for Cell Biology, Biocenter, Medical University of Innsbruck, Austria.
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10
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Yang W, Wang S, Loor JJ, Jiang Q, Gao C, Yang M, Tian Y, Fan W, Zhao Y, Zhang B, Xu C. Role of sortilin 1 (SORT1) on lipid metabolism in bovine liver. J Dairy Sci 2022; 105:5420-5434. [DOI: 10.3168/jds.2021-21607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Accepted: 02/27/2022] [Indexed: 11/19/2022]
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11
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Molecular Biological and Clinical Understanding of the Statin Residual Cardiovascular Disease Risk and Peroxisome Proliferator-Activated Receptor Alpha Agonists and Ezetimibe for Its Treatment. Int J Mol Sci 2022; 23:ijms23073418. [PMID: 35408799 PMCID: PMC8998547 DOI: 10.3390/ijms23073418] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/11/2022] [Accepted: 03/17/2022] [Indexed: 12/20/2022] Open
Abstract
Several randomized, double blind, placebo-controlled trials (RCTs) have demonstrated that low-density lipoprotein cholesterol (LDL-C) lowering by using statins, including high-doses of strong statins, reduced the development of cardiovascular disease (CVD). However, among the eight RCTs which investigated the effect of statins vs. placebos on the development of CVD, 56-79% of patients had the residual CVD risk after the trials. In three RCTs which investigated the effect of a high dose vs. a usual dose of statins on the development of CVD, 78-87% of patients in the high-dose statin arms still had the CVD residual risk after the trials. An analysis of the characteristics of patients in the RCTs suggests that elevated triglyceride (TG) and reduced high-density lipoprotein cholesterol (HDL-C), the existence of obesity/insulin resistance, and diabetes may be important metabolic factors which determine the statin residual CVD risk. To understand the association between lipid abnormalities and the development of atherosclerosis, we show the profile of lipoproteins and their normal metabolism, and the molecular and biological mechanisms for the development of atherosclerosis by high TG and/or low HDL-C in insulin resistance. The molecular biological mechanisms for the statin residual CVD risk include an increase of atherogenic lipoproteins such as small dense LDL and remnants, vascular injury and remodeling by inflammatory cytokines, and disturbed reverse cholesterol transport. Peroxisome proliferator-activated receptor alpha (PPARα) agonists improve atherogenic lipoproteins, reverse the cholesterol transport system, and also have vascular protective effects, such as an anti-inflammatory effect and the reduction of the oxidative state. Ezetimibe, an inhibitor of intestinal cholesterol absorption, also improves TG and HDL-C, and reduces intestinal cholesterol absorption and serum plant sterols, which are increased by statins and are atherogenic, possibly contributing to reduce the statin residual CVD risk.
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12
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Yanai H, Katsuyama H, Hakoshima M. Effects of a Novel Selective Peroxisome Proliferator-Activated Receptor α Modulator, Pemafibrate, on Metabolic Parameters: A Retrospective Longitudinal Study. Biomedicines 2022; 10:biomedicines10020401. [PMID: 35203610 PMCID: PMC8962310 DOI: 10.3390/biomedicines10020401] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/27/2022] [Accepted: 02/05/2022] [Indexed: 12/07/2022] Open
Abstract
The modulation of peroxisome proliferator-activated receptors (PPARs), the superfamily of steroid–thyroid–retinoid nuclear receptors, is expected to induce an amazing crosstalk between energy-demanding organs. Here, we aimed to study the effects of the novel selective PPARα modulator, pemafibrate, on metabolic parameters in patients with dyslipidemia. We retrospectively studied patients who had taken pemafibrate and compared metabolic parameters at baseline with the data at 3, 6 and 12 months after the start of pemafibrate. Serum triglyceride significantly decreased and high-density lipoprotein-cholesterol significantly increased at 3, 6 and 12 months after the start of pemafibrate. Serum aspartate aminotransferase levels significantly decreased at 3 and 6 after the start of pemafibrate as compared with baseline. Serum alanine aminotransferase and gamma-glutamyl transferase significantly decreased and albumin significantly increased after 3, 6 and 12 months. HbA1c levels significantly decreased after 3 months. Further, serum uric acid significantly decreased after 12 months. Such metabolic favorable changes due to pemafibrate were significantly correlated with changes in serum lipids. In conclusion, we observed a significant improvement of liver function, HbA1c and serum uric acid along with an amelioration of dyslipidemia after the start of pemafibrate.
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13
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Conlon DM, Schneider CV, Ko YA, Rodrigues A, Guo K, Hand NJ, Rader DJ. Sortilin restricts secretion of apolipoprotein B-100 by hepatocytes under stressed but not basal conditions. J Clin Invest 2022; 132:144334. [PMID: 35113816 PMCID: PMC8920325 DOI: 10.1172/jci144334] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 02/02/2022] [Indexed: 12/02/2022] Open
Abstract
Genetic variants at the SORT1 locus in humans, which cause increased SORT1 expression in the liver, are significantly associated with reduced plasma levels of LDL cholesterol and apolipoprotein B (apoB). However, the role of hepatic sortilin remains controversial, as genetic deletion of sortilin in mice has resulted in variable and conflicting effects on apoB secretion. Here, we found that Sort1-KO mice on a chow diet and several Sort1-deficient hepatocyte lines displayed no difference in apoB secretion. When these models were challenged with high-fat diet or ER stress, the loss of Sort1 expression resulted in a significant increase in apoB-100 secretion. Sort1-overexpression studies yielded reciprocal results. Importantly, carriers of SORT1 variant with diabetes had larger decreases in plasma apoB, TG, and VLDL and LDL particle number as compared with people without diabetes with the same variants. We conclude that, under basal nonstressed conditions, loss of sortilin has little effect on hepatocyte apoB secretion, whereas, in the setting of lipid loading or ER stress, sortilin deficiency leads to increased apoB secretion. These results are consistent with the directionality of effect in human genetics studies and suggest that, under stress conditions, hepatic sortilin directs apoB toward lysosomal degradation rather than secretion, potentially serving as a quality control step in the apoB secretion pathway in hepatocytes.
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Affiliation(s)
- Donna M Conlon
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States of America
| | - Carolin V Schneider
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States of America
| | - Yi-An Ko
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States of America
| | - Amrith Rodrigues
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States of America
| | - Kathy Guo
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States of America
| | - Nicholas J Hand
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States of America
| | - Daniel J Rader
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States of America
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14
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Bristow CL, Winston R. Alphataxin, an Orally Available Small Molecule, Decreases LDL Levels in Mice as a Surrogate for the LDL-Lowering Activity of Alpha-1 Antitrypsin in Humans. Front Pharmacol 2021; 12:695971. [PMID: 34177602 PMCID: PMC8220083 DOI: 10.3389/fphar.2021.695971] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 05/24/2021] [Indexed: 11/13/2022] Open
Abstract
The abundant blood protein α1-proteinase inhibitor (α1PI, Αlpha-1, α1-antitrypsin, SerpinA1) is known to bind to the active site of granule-associated human leukocyte elastase (HLE-G). Less well known is that binding of α1PI to cell surface HLE (HLE-CS) induces lymphocyte locomotion mediated by members of the low density lipoprotein receptor family (LDL-RFMs) thereby facilitating low density lipoprotein (LDL) clearance. LDL and α1PI were previously shown to be in negative feedback regulation during transport and clearance of lipoproteins. Further examination herein of the influence of α1PI in lipoprotein regulation using data from a small randomized, double-blind clinical trial shows that treatment of HIV-1-infected individuals with α1PI plasma products lowered apolipoprotein and lipoprotein levels including LDL. Although promising, plasma-purified α1PI is limited in quantity and not a feasible treatment for the vast number of people who need treatment for lowering LDL levels. We sought to develop orally available small molecules to act as surrogates for α1PI. Small molecule β-lactams are highly characterized for their binding to the active site of HLE-G including crystallographic studies at 1.84 Å. Using high throughput screening (HLE-G inhibition, HLE-CS-induced cellular locomotion), we show here that a panel of β-lactams, including the LDL-lowering drug ezetimibe, have the capacity to act as surrogates for α1PI by binding to HLE-G and HLE-CS. Because β-lactams are antibiotics that also have the capacity to promote evolution of antibiotic resistant bacteria, we modified the β-lactam Alphataxin to prevent antibiotic activity. We demonstrate using the diet-induced obesity (DIO) mouse model that Alphataxin, a penam, is as effective in lowering LDL levels as FDA-approved ezetimibe, a monobactam. Non-antibiotic β-lactams provide a promising new therapeutic class of small molecules for lowering LDL levels.
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Affiliation(s)
- Cynthia L Bristow
- Alpha-1 Biologics, Long Island High Technology Incubator, Stony Brook University, Stony Brook, NY, United States.,Institute for Human Genetics and Biochemistry, Vesenaz, Switzerland
| | - Ronald Winston
- Alpha-1 Biologics, Long Island High Technology Incubator, Stony Brook University, Stony Brook, NY, United States.,Institute for Human Genetics and Biochemistry, Vesenaz, Switzerland
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15
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Mouskeftara T, Goulas A, Ioannidou D, Ntenti C, Agapakis D, Assimopoulou A, Gika H. A Study of Blood Fatty Acids Profile in Hyperlipidemic and Normolipidemic Subjects in Association with Common PNPLA3 and ABCB1 Polymorphisms. Metabolites 2021; 11:metabo11020090. [PMID: 33557317 PMCID: PMC7915980 DOI: 10.3390/metabo11020090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 01/28/2021] [Accepted: 01/29/2021] [Indexed: 01/06/2023] Open
Abstract
Adiponutrin (patatin-like phospholipase domain-containing 3; PNPLA3), encoded in humans by the PNPLA3 gene, is a protein associated with lipid droplet and endoplasmic reticulum membranes, where it is apparently involved in fatty acid redistribution between triglycerides and phospholipids. A common polymorphism of PNPLA3 (I148M, rs738409), linked to increased PNPLA3 presence on lipid droplets, is a strong genetic determinant of non-alcoholic fatty liver disease (NAFLD) and of its progression. P-glycoprotein (Pgp, MDR1—multidrug resistance protein 1, ABCB1—ATP-binding cassette sub-family B member 1), encoded by the ABCB1 gene, is another membrane protein implicated in lipid homeostasis and steatosis. In the past, common ABCB1 polymorphisms have been associated with the distribution of serum lipids but not with fatty acids (FA) profiles. Similarly, data on the effect of PNPLA3 I148M polymorphism on blood FAs are scarce. In this study, a gas chromatography-flame ionization detection (GC-FID) method was optimized, allowing us to analyze twenty FAs (C14: 0, C15: 0, C15: 1, C16: 0, C16: 1, C17: 0, C17: 1, C18: 0, C18: 1cis, C18: 2cis, C20: 0, C20: 1n9, C20: 2, C20: 3n6, C20: 4n6, C20: 5, C23: 0, C24: 0, C24: 1 and C22: 6) in whole blood, based on the indirect determination of the fatty acids methyl esters (FAMES), in 62 hyperlipidemic patients and 42 normolipidemic controls. FA concentrations were then compared between the different genotypes of the rs738409 and rs2032582 (ABCB1 G2677T) polymorphisms, within and between the hyperlipidemic and normolipidemic groups. The rs738409 polymorphism appears to exert a significant effect on the distribution of blood fatty acids, in a lipidemic and fatty acid saturation state-depending manner. The effect of rs2032582 was less pronounced, but the polymorphism did appear to affect the relative distribution of blood fatty acids between hyperlipidemic patients and normolipidemic controls.
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Affiliation(s)
- Thomai Mouskeftara
- Laboratory of Forensic Medicine and Toxicology, School of Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece;
- Biomic AUTh, Center for Interdisciplinary Research and Innovation (CIRI-AUTH), 57001 Thessaloniki, Greece
| | - Antonis Goulas
- Laboratory of Pharmacology, School of Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (A.G.); (D.I.); (C.N.)
| | - Despoina Ioannidou
- Laboratory of Pharmacology, School of Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (A.G.); (D.I.); (C.N.)
| | - Charikleia Ntenti
- Laboratory of Pharmacology, School of Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (A.G.); (D.I.); (C.N.)
| | - Dimitris Agapakis
- Department of Internal Medicine, AHEPA Hospital, School of Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece;
| | - Andreana Assimopoulou
- Natural Products Research Center of Excellence (NatPro-AUTH), Center for Interdisciplinary Research and Innovation (CIRI-AUTH), 57001 Thessaloniki, Greece;
- Laboratory of Organic Chemistry, School of Chemical Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
| | - Helen Gika
- Laboratory of Forensic Medicine and Toxicology, School of Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece;
- Biomic AUTh, Center for Interdisciplinary Research and Innovation (CIRI-AUTH), 57001 Thessaloniki, Greece
- Correspondence:
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16
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Zhou F, Wu X, Pinos I, Abraham BM, Barrett TJ, von Lintig J, Fisher EA, Amengual J. β-Carotene conversion to vitamin A delays atherosclerosis progression by decreasing hepatic lipid secretion in mice. J Lipid Res 2020; 61:1491-1503. [PMID: 32963037 DOI: 10.1194/jlr.ra120001066] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Atherosclerosis is characterized by the pathological accumulation of cholesterol-laden macrophages in the arterial wall. Atherosclerosis is also the main underlying cause of CVDs, and its development is largely driven by elevated plasma cholesterol. Strong epidemiological data find an inverse association between plasma β-carotene with atherosclerosis, and we recently showed that β-carotene oxygenase 1 (BCO1) activity, responsible for β-carotene cleavage to vitamin A, is associated with reduced plasma cholesterol in humans and mice. In this study, we explore whether intact β-carotene or vitamin A affects atherosclerosis progression in the atheroprone LDLR-deficient mice. Compared with control-fed Ldlr-/- mice, β-carotene-supplemented mice showed reduced atherosclerotic lesion size at the level of the aortic root and reduced plasma cholesterol levels. These changes were absent in Ldlr-/- /Bco1-/- mice despite accumulating β-carotene in plasma and atherosclerotic lesions. We discarded the implication of myeloid BCO1 in the development of atherosclerosis by performing bone marrow transplant experiments. Lipid production assays found that retinoic acid, the active form of vitamin A, reduced the secretion of newly synthetized triglyceride and cholesteryl ester in cell culture and mice. Overall, our findings provide insights into the role of BCO1 activity and vitamin A in atherosclerosis progression through the regulation of hepatic lipid metabolism.
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Affiliation(s)
- Felix Zhou
- Cardiovascular Research Center, Leon H. Charney Division of Cardiology, Department of Medicine, New York University Grossman School of Medicine, New York, NY, USA
| | - Xiaoyun Wu
- Department of Food Science and Human Nutrition, University of Illinois Urbana Champaign, Urbana, IL, USA
| | - Ivan Pinos
- Department of Food Science and Human Nutrition, University of Illinois Urbana Champaign, Urbana, IL, USA.,Division of Nutritional Sciences, University of Illinois Urbana Champaign, Urbana, IL, USA
| | - Benjamin M Abraham
- Department of Food Science and Human Nutrition, University of Illinois Urbana Champaign, Urbana, IL, USA
| | - Tessa J Barrett
- Cardiovascular Research Center, Leon H. Charney Division of Cardiology, Department of Medicine, New York University Grossman School of Medicine, New York, NY, USA
| | - Johannes von Lintig
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Edward A Fisher
- Cardiovascular Research Center, Leon H. Charney Division of Cardiology, Department of Medicine, New York University Grossman School of Medicine, New York, NY, USA
| | - Jaume Amengual
- Department of Food Science and Human Nutrition, University of Illinois Urbana Champaign, Urbana, IL, USA .,Division of Nutritional Sciences, University of Illinois Urbana Champaign, Urbana, IL, USA
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17
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Wang J, Wang F, Yuan L, Wu Y, Peng X, Kai G, Zhu S, Liu Y. Aqueous extracts of Lindera aggregate (Sims) Kosterm leaves regulate serum/hepatic lipid and liver function in normal and hypercholesterolemic mice. J Pharmacol Sci 2020; 143:45-51. [PMID: 32169433 DOI: 10.1016/j.jphs.2020.01.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 01/01/2020] [Accepted: 01/21/2020] [Indexed: 02/06/2023] Open
Abstract
The leaves of Lindera aggregate (Sims) Kosterm. are traditionally used as healthy tea for the prevention and treatment of hyperlipidemia in Chinese. The aim of this study was to evaluate the antihyperlipidemic effects and potential mechanisms of the aqueous extracts from L. aggregate leaves (AqLA-L) on normal and hypercholesterolemic (HCL) mice. HCL mice were induced by high fat diet (HFD) and orally administrated with or without AqLA-L for ten days. The results showed that AqLA-L (0.3, 0.6, 1.2 g/kg) significantly reduced serum TG, ALT, but elevated fecal TG in normal mice. AqLA-L (0.3, 0.6, 1.2 g/kg) also remarkably lowered serum TC, TG, LDL, N-HDL, ALT, GLU, APOB, hepatic GLU and increased serum HDL, APOA-I, fecal TG levels in HCL mice. These results revealed that AqLA-L treatment regulated the disorders of the serum lipid and liver function, reduced hepatic GLU contents both in normal and HCL mice. The potential mechanisms for cholesterol-lowering effects of AqLA-L might be up-regulation of cholesterol 7-alpha-hydroxylase (CYP7A1) and ATP-binding cassette transporter A1 (ABCA1), as well as down-regulation of 3-hydroxy-3-methylglutaryl CoA reductase (HMGCR). The data indicated that AqLA-L has potential therapeutic value in treatment of hyperlipidemia with great application security.
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Affiliation(s)
- Juan Wang
- Institute of Biopharmaceutical, Zhejiang Pharmaceutical College, Zhejiang Province, Ningbo 315100, PR China
| | - Furong Wang
- Institute of Biopharmaceutical, Zhejiang Pharmaceutical College, Zhejiang Province, Ningbo 315100, PR China
| | - Lixia Yuan
- Institute of Biopharmaceutical, Zhejiang Pharmaceutical College, Zhejiang Province, Ningbo 315100, PR China
| | - Yao Wu
- Institute of Biopharmaceutical, Zhejiang Pharmaceutical College, Zhejiang Province, Ningbo 315100, PR China
| | - Xin Peng
- Institute of Biopharmaceutical, Zhejiang Pharmaceutical College, Zhejiang Province, Ningbo 315100, PR China.
| | - Guoyin Kai
- Zhejiang Chinese Medical University, Zhejiang Province, Hangzhou 311400, PR China
| | - ShaoFeng Zhu
- Institute of Biopharmaceutical, Zhejiang Pharmaceutical College, Zhejiang Province, Ningbo 315100, PR China
| | - Yugang Liu
- Institute of Biopharmaceutical, Zhejiang Pharmaceutical College, Zhejiang Province, Ningbo 315100, PR China
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18
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Abstract
The placenta, a hallmark of mammalian embryogenesis, allows nutrients to be exchanged between the mother and the fetus. Vitamin A (VA), an essential nutrient, cannot be synthesized by the embryo, and must be acquired from the maternal circulation through the placenta. Our understanding of how this transfer is accomplished is still in its infancy. In this chapter, we recapitulate the early studies about the relationship between maternal dietary/supplemental VA intake and fetal VA levels. We then describe how the discovery of retinol-binding protein (RBP or RBP4), the development of labeling and detection techniques, and the advent of knockout mice shifted this field from a macroscopic to a molecular level. The most recent data indicate that VA and its derivatives (retinoids) and the pro-VA carotenoid, β-carotene, are transferred across the placenta by distinct proteins, some of which overlap with proteins involved in lipoprotein uptake. The VA status and dietary intake of the mother influence the expression of these proteins, creating feedback signals that control the uptake of retinoids and that may also regulate the uptake of lipids, raising the intriguing possibility of crosstalk between micronutrient and macronutrient metabolism. Many questions remain about the temporal and spatial patterns by which these proteins are expressed and transferred throughout gestation. The answers to these questions are highly relevant to human health, considering that those with either limited or excessive intake of retinoids/carotenoids during pregnancy may be at risk of obtaining improper amounts of VA that ultimately impact the development and health of their offspring.
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19
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Walsh MT, Celestin OM, Thierer JH, Rajan S, Farber SA, Hussain MM. Model systems for studying the assembly, trafficking, and secretion of apoB lipoproteins using fluorescent fusion proteins. J Lipid Res 2020; 61:316-327. [PMID: 31888978 DOI: 10.1194/jlr.ra119000259] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 12/24/2019] [Indexed: 11/20/2022] Open
Abstract
apoB exists as apoB100 and apoB48, which are mainly found in hepatic VLDLs and intestinal chylomicrons, respectively. Elevated plasma levels of apoB-containing lipoproteins (Blps) contribute to coronary artery disease, diabetes, and other cardiometabolic conditions. Studying the mechanisms that drive the assembly, intracellular trafficking, secretion, and function of Blps remains challenging. Our understanding of the intracellular and intraorganism trafficking of Blps can be greatly enhanced, however, with the availability of fusion proteins that can help visualize Blp transport within cells and between tissues. We designed three plasmids expressing human apoB fluorescent fusion proteins: apoB48-GFP, apoB100-GFP, and apoB48-mCherry. In Cos-7 cells, transiently expressed fluorescent apoB proteins colocalized with calnexin and were only secreted if cells were cotransfected with microsomal triglyceride transfer protein. The secreted apoB-fusion proteins retained the fluorescent protein and were secreted as lipoproteins with flotation densities similar to plasma HDL and LDL. In a rat hepatoma McA-RH7777 cell line, the human apoB100 fusion protein was secreted as VLDL- and LDL-sized particles, and the apoB48 fusion proteins were secreted as LDL- and HDL-sized particles. To monitor lipoprotein trafficking in vivo, the apoB48-mCherry construct was transiently expressed in zebrafish larvae and was detected throughout the liver. These experiments show that the addition of fluorescent proteins to the C terminus of apoB does not disrupt their assembly, localization, secretion, or endocytosis. The availability of fluorescently labeled apoB proteins will facilitate the exploration of the assembly, degradation, and transport of Blps and help to identify novel compounds that interfere with these processes via high-throughput screening.
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Affiliation(s)
- Meghan T Walsh
- Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, New York
| | - Oni M Celestin
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD
| | - James H Thierer
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD
| | - Sujith Rajan
- Department of Foundations of Medicine, New York University Long Island School of Medicine, Mineola, NY.,Diabetes and Obesity Research Center, New York University Winthrop Hospital, Mineola, NY
| | - Steven A Farber
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD
| | - M Mahmood Hussain
- Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, New York .,Department of Foundations of Medicine, New York University Long Island School of Medicine, Mineola, NY.,Diabetes and Obesity Research Center, New York University Winthrop Hospital, Mineola, NY.,Department of Veterans Affairs New York Harbor Healthcare System, Brooklyn, NY
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20
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Yanai H, Hirowatari Y, Yoshida H. Diabetic dyslipidemia: evaluation and mechanism. Glob Health Med 2019; 1:30-35. [PMID: 33330752 DOI: 10.35772/ghm.2019.01007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 09/20/2019] [Accepted: 09/30/2019] [Indexed: 01/14/2023]
Abstract
Diabetes is one of the well-established independent risk factors for cardiovascular diseases. Diabetes induces dyslipidemia which is characterized by elevated fasting triglyceride (TG) and reduced high-density lipoprotein-cholesterol (HDL-C), and such diabetic dyslipidemia is a crucial determinant for atherogenesis and atherosclerotic progression in patients with diabetes. Previous measurement methods of lipoproteins have problems including time-consuming (ultracentrifugation) and inaccurate and impossible measurements of TG-rich lipoproteins such as chylomicron, intermediate-density lipoprotein (IDL) and very low-density lipoprotein (VLDL). Our developed anion-exchange high-performance liquid chromatography (AEX-HPLC) can measure all fractions of lipoproteins accurately. Our studies using AEX-HPLC showed that IDL and VLDL in type 2 diabetes were higher than non-diabetic subjects, and IDL and VLDL were higher in the order of type 2 diabetic patients with obesity, type 2 diabetic patients without obesity, and non-diabetic subjects. Here, we also describe the underlying mechanisms for development of diabetic dyslipidemia.
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Affiliation(s)
- Hidekatsu Yanai
- Department of Internal Medicine, National Center for Global Health and Medicine Kohnodai Hospital, Chiba, Japan
| | - Yuji Hirowatari
- Laboratory Sciences, Department of Health Sciences, School of Health and Social Service, Saitama Prefectural University, Saitama, Japan
| | - Hiroshi Yoshida
- Department of Laboratory Medicine, The Jikei University Kashiwa Hospital, Chiba, Japan
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21
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Demir İ, Yildirim Akan O, Guler A, Bozkaya G, Aslanipour B, Calan M. Relation of Decreased Circulating Sortilin Levels With Unfavorable Metabolic Profiles in Subjects With Newly Diagnosed Type 2 Diabetes Mellitus. Am J Med Sci 2019; 359:8-16. [PMID: 31902442 DOI: 10.1016/j.amjms.2019.10.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 10/01/2019] [Accepted: 10/15/2019] [Indexed: 01/19/2023]
Abstract
BACKGROUND Sortilin, a pluripotent peptide hormone, plays a role in glucose and lipid metabolism. A link between sortilin and insulin sensitivity has been implicated. However, the clinical implications of this link remain elusive. Our aims were to investigate whether sortilin levels were altered in subjects with newly diagnosed type 2 diabetes mellitus (nT2DM) compared with subjects with normal glucose tolerance (NGT) and to determine whether a link exist between sortilin levels and metabolic parameters. MATERIALS AND METHODS A total of 150 subjects including 75 nT2DM patients and 75 subjects with NGT who were matched in age, body mass index, and sex were enrolled into this case-control study. The circulating levels of sortilin were measured using enzyme-linked immunosorbent assay. A 2-hour 75-g oral glucose tolerance test was used for diagnosis of T2DM. Metabolic parameters of enrolled subjects were also determined. RESULTS The circulating levels of sortilin were found to be significantly lower in subjects with nT2DM than in controls (138.44 ± 38.39 vs. 184.93 ± 49.67 pg/mL, P < 0.001). Sortilin levels showed a negative correlation with insulin resistance and unfavorable lipid profiles, while they were positively correlated with high-density lipoprotein cholesterol in subjects with nT2DM. Linear regression analysis showed an independent and inverse link between sortilin and insulin resistance and unfavorable lipid profiles. Moreover, logistic regression analysis revealed that the subjects with the lowest sortilin levels had an increased risk of nT2DM compared with those subjects with the highest sortilin levels. CONCLUSIONS Decreased circulating levels of sortilin were associated with unfavorable metabolic profiles in subjects with nT2DM.
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Affiliation(s)
- İsmail Demir
- Division of Endocrinology and Metabolism, Department of Internal Medicine
| | | | | | - Giray Bozkaya
- Department of Clinical Biochemistry, Izmir Bozyaka Training and Research Hospital, Izmir, Turkey
| | - Behnaz Aslanipour
- Department of Biotechnology, Graduate School of Natural and Applied Sciences, Ege University, Izmir, Tukey
| | - Mehmet Calan
- Division of Endocrinology and Metabolism, Department of Internal Medicine.
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22
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Goder V, Alanis-Dominguez E, Bustamante-Sequeiros M. Lipids and their (un)known effects on ER-associated protein degradation (ERAD). Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1865:158488. [PMID: 31233887 DOI: 10.1016/j.bbalip.2019.06.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 06/15/2019] [Accepted: 06/18/2019] [Indexed: 02/09/2023]
Abstract
Endoplasmic reticulum (ER)-associated protein degradation (ERAD) is a conserved cellular process that apart from protein quality control and maintenance of ER membrane identity has pivotal functions in regulating the lipid composition of the ER membrane. A general trigger for ERAD activation is the exposure of normally buried protein domains due to protein misfolding, absence of binding partners or conformational changes. Several feedback loops for ER lipid homeostasis exploit the induction of conformational changes in key enzymes of lipid biosynthesis or in ER membrane-embedded transcription factors upon shortage or abundance of specific lipids, leading to enzyme degradation or mobilization of transcription factors. Similarly, an insufficient amount of lipids triggers ERAD of apolipoproteins during lipoprotein formation. Lipids might even have a role in ER protein quality control: when proteins destined for ER export are covalently modified with lipids their ER residence time and their susceptibility to ERAD is reduced. Here we summarize and compare the various interconnections of lipids with ER membrane proteins and ERAD. This article is part of a Special Issue entitled Endoplasmic reticulum platforms for lipid dynamics edited by Shamshad Cockcroft and Christopher Stefan.
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Affiliation(s)
- Veit Goder
- Department of Genetics, University of Seville, 6, Ave Reina Mercedes, 41012 Seville, Spain.
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23
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Abstract
PURPOSE OF REVIEW Sortilin, encoded SORT1 gene at chromosome 1p13.3, is a multiligand receptor that traffics protein from the Golgi to the endosomes, secretory vesicles, and the cell surface. Genome-wide association studies (GWAS) revealed an association between sortilin and reduced plasma LDL-cholesterol (LDL-C) as well as reduced coronary artery disease (CAD). This review explores the various lipid metabolism pathways that are affected by alterations in sortilin expression. RECENT FINDINGS The effects of increased hepatic sortilin on plasma LDL-C levels are mediated by increased clearance of LDL-C and decreased very LDL (VLDL) secretion because of increased autophagy-mediated lysosomal degradation of apolipoproteinB100. Sort1 knockout models have shown opposite VLDL secretion phenotypes as well as whole body lipid metabolism in response to diet challenges, leading to confusion about the true role of sortilin in the liver and other tissues. SUMMARY The regulation of VLDL secretion by hepatic sortilin is complex and remains incompletely understood. Further investigation to determine the specific conditions under which both hepatic sortilin and total body sortilin cause changes in lipid metabolism pathways is needed.
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Affiliation(s)
- Donna M Conlon
- Division of Translational Medicine and Human Genetics, Department of Medicine, University of Pennsylvania, Philadelphia, USA
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24
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Stanhope KL, Goran MI, Bosy-Westphal A, King JC, Schmidt LA, Schwarz JM, Stice E, Sylvetsky AC, Turnbaugh PJ, Bray GA, Gardner CD, Havel PJ, Malik V, Mason AE, Ravussin E, Rosenbaum M, Welsh JA, Allister-Price C, Sigala DM, Greenwood MRC, Astrup A, Krauss RM. Pathways and mechanisms linking dietary components to cardiometabolic disease: thinking beyond calories. Obes Rev 2018; 19:1205-1235. [PMID: 29761610 PMCID: PMC6530989 DOI: 10.1111/obr.12699] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 03/09/2018] [Accepted: 03/31/2018] [Indexed: 12/11/2022]
Abstract
Calories from any food have the potential to increase risk for obesity and cardiometabolic disease because all calories can directly contribute to positive energy balance and fat gain. However, various dietary components or patterns may promote obesity and cardiometabolic disease by additional mechanisms that are not mediated solely by caloric content. Researchers explored this topic at the 2017 CrossFit Foundation Academic Conference 'Diet and Cardiometabolic Health - Beyond Calories', and this paper summarizes the presentations and follow-up discussions. Regarding the health effects of dietary fat, sugar and non-nutritive sweeteners, it is concluded that food-specific saturated fatty acids and sugar-sweetened beverages promote cardiometabolic diseases by mechanisms that are additional to their contribution of calories to positive energy balance and that aspartame does not promote weight gain. The challenges involved in conducting and interpreting clinical nutritional research, which preclude more extensive conclusions, are detailed. Emerging research is presented exploring the possibility that responses to certain dietary components/patterns are influenced by the metabolic status, developmental period or genotype of the individual; by the responsiveness of brain regions associated with reward to food cues; or by the microbiome. More research regarding these potential 'beyond calories' mechanisms may lead to new strategies for attenuating the obesity crisis.
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Affiliation(s)
- K L Stanhope
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - M I Goran
- Department of Preventive Medicine, Diabetes and Obesity Research Institute, University of Southern California, Los Angeles, CA, USA
| | - A Bosy-Westphal
- Institute of Human Nutrition and Food Science, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - J C King
- Children's Hospital Oakland Research Institute, Oakland, CA, USA
| | - L A Schmidt
- Philip R. Lee Institute for Health Policy Studies, University of California, San Francisco, San Francisco, CA, USA.,California Clinical and Translational Science Institute, University of California, San Francisco, San Francisco, CA, USA.,Department of Anthropology, History, and Social Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - J-M Schwarz
- Touro University, Vallejo, CA, USA.,Department of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - E Stice
- Oregon Research Institute, Eugene, OR, USA
| | - A C Sylvetsky
- Department of Exercise and Nutrition Sciences, Milken Institute School of Public Health, The George Washington University, Washington, DC, USA
| | - P J Turnbaugh
- Department of Microbiology and Immunology, G.W. Hooper Research Foundation, University of California, San Francisco, San Francisco, CA, USA
| | - G A Bray
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA
| | - C D Gardner
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - P J Havel
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA.,Department of Nutrition, University of California, Davis, Davis, CA, USA
| | - V Malik
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - A E Mason
- Department of Psychiatry, Osher Center for Integrative Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - E Ravussin
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA
| | - M Rosenbaum
- Division of Molecular Genetics, Department of Pediatrics, Columbia University, New York, NY, USA
| | - J A Welsh
- Department of Pediatrics, Emory University School of Medicine, Wellness Department, Children's Healthcare of Atlanta, Nutrition and Health Sciences Doctoral Program, Laney Graduate School, Emory University, Atlanta, GA, USA
| | - C Allister-Price
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - D M Sigala
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - M R C Greenwood
- Department of Nutrition, University of California, Davis, Davis, CA, USA
| | - A Astrup
- Department of Nutrition, Exercise, and Sports, Faculty of Sciences, University of Copenhagen, Copenhagen, Denmark
| | - R M Krauss
- Children's Hospital Oakland Research Institute, Oakland, CA, USA
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25
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Dijk W, Le May C, Cariou B. Beyond LDL: What Role for PCSK9 in Triglyceride-Rich Lipoprotein Metabolism? Trends Endocrinol Metab 2018; 29:420-434. [PMID: 29665987 DOI: 10.1016/j.tem.2018.03.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 03/10/2018] [Accepted: 03/15/2018] [Indexed: 10/17/2022]
Abstract
Elevated plasma triglyceride (TG) levels are an independent risk factor for cardiovascular disease (CVD). Proprotein convertase subtilisin-kexin 9 (PCSK9) - a protein therapeutically targeted to lower plasma cholesterol levels - might regulate plasma TG-rich lipoprotein (TRL) levels. We provide a timely and critical review of the current evidence for a role of PCSK9 in TRL metabolism by assessing the impact of PCSK9 gene variants, by reviewing recent clinical data with PCSK9 inhibitors, and by describing the potential mechanisms by which PCSK9 might regulate TRL metabolism. We conclude that the impact of PCSK9 on TRL metabolism is relatively modest, especially compared to its impact on cholesterol metabolism.
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Affiliation(s)
- Wieneke Dijk
- L'institut du thorax, INSERM, CNRS, Université de Nantes, Nantes, France
| | - Cédric Le May
- L'institut du thorax, INSERM, CNRS, Université de Nantes, Nantes, France
| | - Bertrand Cariou
- L'institut du thorax, INSERM, CNRS, Université de Nantes, Nantes, France; L'institut du thorax, Department of Endocrinology, CHU NANTES, Nantes, France.
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26
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Grünig D, Felser A, Duthaler U, Bouitbir J, Krähenbühl S. Effect of the Catechol-O-Methyltransferase Inhibitors Tolcapone and Entacapone on Fatty Acid Metabolism in HepaRG Cells. Toxicol Sci 2018; 164:477-488. [DOI: 10.1093/toxsci/kfy101] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- David Grünig
- Division of Clinical Pharmacology & Toxicology, University Hospital Basel, 4031 Basel, Switzerland
- Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Andrea Felser
- Division of Clinical Pharmacology & Toxicology, University Hospital Basel, 4031 Basel, Switzerland
- Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
- Division of Clinical Pharmacology & Toxicology, University Hospital Basel, 4031 Basel, Switzerland
| | - Urs Duthaler
- Division of Clinical Pharmacology & Toxicology, University Hospital Basel, 4031 Basel, Switzerland
- Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
- Division of Clinical Pharmacology & Toxicology, University Hospital Basel, 4031 Basel, Switzerland
| | - Jamal Bouitbir
- Division of Clinical Pharmacology & Toxicology, University Hospital Basel, 4031 Basel, Switzerland
- Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
- Swiss Center for Applied Human Toxicology (SCAHT), 4055 Basel, Switzerland
| | - Stephan Krähenbühl
- Division of Clinical Pharmacology & Toxicology, University Hospital Basel, 4031 Basel, Switzerland
- Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
- Swiss Center for Applied Human Toxicology (SCAHT), 4055 Basel, Switzerland
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27
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Sirwi A, Hussain MM. Lipid transfer proteins in the assembly of apoB-containing lipoproteins. J Lipid Res 2018; 59:1094-1102. [PMID: 29650752 DOI: 10.1194/jlr.r083451] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 04/12/2018] [Indexed: 11/20/2022] Open
Abstract
A better understanding of intracellular lipoprotein assembly may help identify proteins with important roles in lipid disorders. apoB-containing lipoproteins (B-lps) are macromolecular lipid and protein micelles that act as specialized transport vehicles for hydrophobic lipids. They are assembled predominantly in enterocytes and hepatocytes to transport dietary and endogenous fat, respectively, to different tissues. Assembly occurs in the endoplasmic reticulum (ER) and is dependent on lipid resynthesis in the ER and on a chaperone, namely, microsomal triglyceride transfer protein (MTTP). Precursors for lipid synthesis are obtained from extracellular sources and from cytoplasmic lipid droplets. MTTP is the major and essential lipid transfer protein that transfers phospholipids and triacylglycerols to nascent apoB for the assembly of lipoproteins. Assembly is aided by cell death-inducing DFF45-like effector B and by phospholipid transfer protein, which may facilitate additional deposition of triacylglycerols and phospholipids, respectively, to apoB. Here, we summarize the current understanding of the different steps in the assembly of B-lps and discuss the role of lipid transfer proteins in these steps to help identify new clinical targets for lipid-associated disorders, such as heart disease.
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Affiliation(s)
- Alaa Sirwi
- School of Graduate Studies, Molecular and Cell Biology Program, State University of New York Downstate Medical Center, Brooklyn, NY
| | - M Mahmood Hussain
- New York University Winthrop Hospital, Mineola, NY and Veterans Affairs New York Harbor Healthcare System, Brooklyn, NY
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28
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Ehrhardt N, Doche ME, Chen S, Mao HZ, Walsh MT, Bedoya C, Guindi M, Xiong W, Ignatius Irudayam J, Iqbal J, Fuchs S, French SW, Mahmood Hussain M, Arditi M, Arumugaswami V, Péterfy M. Hepatic Tm6sf2 overexpression affects cellular ApoB-trafficking, plasma lipid levels, hepatic steatosis and atherosclerosis. Hum Mol Genet 2018; 26:2719-2731. [PMID: 28449094 DOI: 10.1093/hmg/ddx159] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Accepted: 04/21/2017] [Indexed: 12/15/2022] Open
Abstract
The human transmembrane 6 superfamily member 2 (TM6SF2) gene has been implicated in plasma lipoprotein metabolism, alcoholic and non-alcoholic fatty liver disease and myocardial infarction in multiple genome-wide association studies. To investigate the role of Tm6sf2 in metabolic homeostasis, we generated mice with elevated expression using adeno-associated virus (AAV)-mediated gene delivery. Hepatic overexpression of mouse Tm6sf2 resulted in phenotypes previously observed in Tm6sf2-deficient mice including reduced plasma lipid levels, diminished hepatic triglycerides secretion and increased hepatosteatosis. Furthermore, increased hepatic Tm6sf2 expression protected against the development of atherosclerosis in LDL-receptor/ApoB48-deficient mice. In cultured human hepatocytes, Tm6sf2 overexpression reduced apolipoprotein B secretion and resulted in its accumulation within the endoplasmic reticulum (ER) suggesting impaired ER-to-Golgi trafficking of pre-very low-density lipoprotein (VLDL) particles. Analysis of two metabolic trait-associated coding polymorphisms in the human TM6SF2 gene (rs58542926 and rs187429064) revealed that both variants impact TM6SF2 expression by affecting the rate of protein turnover. These data demonstrate that rs58542926 (E167K) and rs187429064 (L156P) are functional variants and suggest that they influence metabolic traits through altered TM6SF2 protein stability. Taken together, our results indicate that cellular Tm6sf2 level is an important determinant of VLDL metabolism and further implicate TM6SF2 as a causative gene underlying metabolic disease and trait associations at the 19p13.11 locus.
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Affiliation(s)
- Nicole Ehrhardt
- Department of Basic Medical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA
| | | | - Shuang Chen
- Department of Biomedical Sciences.,Department of Pediatrics.,Infectious and Immunologic Diseases Research Center, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Hui Z Mao
- Department of Basic Medical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Meghan T Walsh
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Candy Bedoya
- Department of Basic Medical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Maha Guindi
- Department of Pathology and Laboratory Medicine
| | - Weidong Xiong
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Joseph Ignatius Irudayam
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Jahangir Iqbal
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Sebastien Fuchs
- Department of Basic Medical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Samuel W French
- Department of Pathology and Laboratory Medicine.,Jonsson Comprehensive Cancer Center.,UCLA AIDS Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - M Mahmood Hussain
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA.,Winthrop-University Hospital, Mineola, NY 11501, USA
| | - Moshe Arditi
- Department of Biomedical Sciences.,Department of Pediatrics.,Infectious and Immunologic Diseases Research Center, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.,Department of Pediatrics
| | - Vaithilingaraja Arumugaswami
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.,Department of Surgery
| | - Miklós Péterfy
- Department of Basic Medical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA.,Department of Biomedical Sciences.,Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
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29
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Amengual J, Guo L, Strong A, Madrigal-Matute J, Wang H, Kaushik S, Brodsky JL, Rader DJ, Cuervo AM, Fisher EA. Autophagy Is Required for Sortilin-Mediated Degradation of Apolipoprotein B100. Circ Res 2018; 122:568-582. [PMID: 29301854 DOI: 10.1161/circresaha.117.311240] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 12/28/2017] [Accepted: 12/29/2017] [Indexed: 12/30/2022]
Abstract
RATIONALE Genome-wide association studies identified single-nucleotide polymorphisms near the SORT1 locus strongly associated with decreased plasma LDL-C (low-density lipoprotein cholesterol) levels and protection from atherosclerotic cardiovascular disease and myocardial infarction. The minor allele of the causal SORT1 single-nucleotide polymorphism locus creates a putative C/EBPα (CCAAT/enhancer-binding protein α)-binding site in the SORT1 promoter, thereby increasing in homozygotes sortilin expression by 12-fold in liver, which is rich in this transcription factor. Our previous studies in mice have showed reductions in plasma LDL-C and its principal protein component, apoB (apolipoprotein B) with increased SORT1 expression, and in vitro studies suggested that sortilin promoted the presecretory lysosomal degradation of apoB associated with the LDL precursor, VLDL (very-low-density lipoprotein). OBJECTIVE To determine directly that SORT1 overexpression results in apoB degradation and to identify the mechanisms by which this reduces apoB and VLDL secretion by the liver, thereby contributing to understanding the clinical phenotype of lower LDL-C levels. METHODS AND RESULTS Pulse-chase studies directly established that SORT1 overexpression results in apoB degradation. As noted above, previous work implicated a role for lysosomes in this degradation. Through in vitro and in vivo studies, we now demonstrate that the sortilin-mediated route of apoB to lysosomes is unconventional and intersects with autophagy. Increased expression of sortilin diverts more apoB away from secretion, with both proteins trafficking to the endosomal compartment in vesicles that fuse with autophagosomes to form amphisomes. The amphisomes then merge with lysosomes. Furthermore, we show that sortilin itself is a regulator of autophagy and that its activity is scaled to the level of apoB synthesis. CONCLUSIONS These results strongly suggest that an unconventional lysosomal targeting process dependent on autophagy degrades apoB that was diverted from the secretory pathway by sortilin and provides a mechanism contributing to the reduced LDL-C found in individuals with SORT1 overexpression.
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Affiliation(s)
- Jaume Amengual
- From the Division of Cardiology (J.A., L.G., H.W., E.A.F.), Department of Medicine (J.A., L.G., H.W., E.A.F.), and Marc and Ruti Bell Program in Vascular Biology (J.A., E.A.F., L.G, H.W.), NYU School of Medicine; Institute for Translational Medicine and Therapeutics, Cardiovascular Institute, and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia (A.S., D.J.R.); Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, New York (J.M.-M., S.K., A.M.C.); and Department of Biological Sciences, University of Pittsburgh, PA (J.L.B.)
| | - Liang Guo
- From the Division of Cardiology (J.A., L.G., H.W., E.A.F.), Department of Medicine (J.A., L.G., H.W., E.A.F.), and Marc and Ruti Bell Program in Vascular Biology (J.A., E.A.F., L.G, H.W.), NYU School of Medicine; Institute for Translational Medicine and Therapeutics, Cardiovascular Institute, and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia (A.S., D.J.R.); Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, New York (J.M.-M., S.K., A.M.C.); and Department of Biological Sciences, University of Pittsburgh, PA (J.L.B.)
| | - Alanna Strong
- From the Division of Cardiology (J.A., L.G., H.W., E.A.F.), Department of Medicine (J.A., L.G., H.W., E.A.F.), and Marc and Ruti Bell Program in Vascular Biology (J.A., E.A.F., L.G, H.W.), NYU School of Medicine; Institute for Translational Medicine and Therapeutics, Cardiovascular Institute, and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia (A.S., D.J.R.); Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, New York (J.M.-M., S.K., A.M.C.); and Department of Biological Sciences, University of Pittsburgh, PA (J.L.B.)
| | - Julio Madrigal-Matute
- From the Division of Cardiology (J.A., L.G., H.W., E.A.F.), Department of Medicine (J.A., L.G., H.W., E.A.F.), and Marc and Ruti Bell Program in Vascular Biology (J.A., E.A.F., L.G, H.W.), NYU School of Medicine; Institute for Translational Medicine and Therapeutics, Cardiovascular Institute, and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia (A.S., D.J.R.); Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, New York (J.M.-M., S.K., A.M.C.); and Department of Biological Sciences, University of Pittsburgh, PA (J.L.B.)
| | - Haizhen Wang
- From the Division of Cardiology (J.A., L.G., H.W., E.A.F.), Department of Medicine (J.A., L.G., H.W., E.A.F.), and Marc and Ruti Bell Program in Vascular Biology (J.A., E.A.F., L.G, H.W.), NYU School of Medicine; Institute for Translational Medicine and Therapeutics, Cardiovascular Institute, and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia (A.S., D.J.R.); Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, New York (J.M.-M., S.K., A.M.C.); and Department of Biological Sciences, University of Pittsburgh, PA (J.L.B.)
| | - Susmita Kaushik
- From the Division of Cardiology (J.A., L.G., H.W., E.A.F.), Department of Medicine (J.A., L.G., H.W., E.A.F.), and Marc and Ruti Bell Program in Vascular Biology (J.A., E.A.F., L.G, H.W.), NYU School of Medicine; Institute for Translational Medicine and Therapeutics, Cardiovascular Institute, and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia (A.S., D.J.R.); Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, New York (J.M.-M., S.K., A.M.C.); and Department of Biological Sciences, University of Pittsburgh, PA (J.L.B.)
| | - Jeffrey L Brodsky
- From the Division of Cardiology (J.A., L.G., H.W., E.A.F.), Department of Medicine (J.A., L.G., H.W., E.A.F.), and Marc and Ruti Bell Program in Vascular Biology (J.A., E.A.F., L.G, H.W.), NYU School of Medicine; Institute for Translational Medicine and Therapeutics, Cardiovascular Institute, and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia (A.S., D.J.R.); Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, New York (J.M.-M., S.K., A.M.C.); and Department of Biological Sciences, University of Pittsburgh, PA (J.L.B.)
| | - Daniel J Rader
- From the Division of Cardiology (J.A., L.G., H.W., E.A.F.), Department of Medicine (J.A., L.G., H.W., E.A.F.), and Marc and Ruti Bell Program in Vascular Biology (J.A., E.A.F., L.G, H.W.), NYU School of Medicine; Institute for Translational Medicine and Therapeutics, Cardiovascular Institute, and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia (A.S., D.J.R.); Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, New York (J.M.-M., S.K., A.M.C.); and Department of Biological Sciences, University of Pittsburgh, PA (J.L.B.)
| | - Ana Maria Cuervo
- From the Division of Cardiology (J.A., L.G., H.W., E.A.F.), Department of Medicine (J.A., L.G., H.W., E.A.F.), and Marc and Ruti Bell Program in Vascular Biology (J.A., E.A.F., L.G, H.W.), NYU School of Medicine; Institute for Translational Medicine and Therapeutics, Cardiovascular Institute, and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia (A.S., D.J.R.); Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, New York (J.M.-M., S.K., A.M.C.); and Department of Biological Sciences, University of Pittsburgh, PA (J.L.B.)
| | - Edward A Fisher
- From the Division of Cardiology (J.A., L.G., H.W., E.A.F.), Department of Medicine (J.A., L.G., H.W., E.A.F.), and Marc and Ruti Bell Program in Vascular Biology (J.A., E.A.F., L.G, H.W.), NYU School of Medicine; Institute for Translational Medicine and Therapeutics, Cardiovascular Institute, and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia (A.S., D.J.R.); Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, New York (J.M.-M., S.K., A.M.C.); and Department of Biological Sciences, University of Pittsburgh, PA (J.L.B.).
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30
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Thibeaux S, Siddiqi S, Zhelyabovska O, Moinuddin F, Masternak MM, Siddiqi SA. Cathepsin B regulates hepatic lipid metabolism by cleaving liver fatty acid-binding protein. J Biol Chem 2017; 293:1910-1923. [PMID: 29259130 DOI: 10.1074/jbc.m117.778365] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 11/15/2017] [Indexed: 12/30/2022] Open
Abstract
Synthesis and secretion of hepatic triglycerides (TAG) associated with very-low-density lipoprotein (VLDL) play a major role in maintaining overall lipid homeostasis. This study aims to identify factors affecting synthesis and secretion of VLDL-TAG using the growth hormone-deficient Ames dwarf mouse model, which has reduced serum TAG. Proteomic analysis coupled with a bioinformatics-driven approach revealed that these mice express greater amounts of hepatic cathepsin B and lower amounts of liver fatty acid-binding protein (LFABP) than their wildtype littermates. siRNA-mediated knockdown of cathepsin B in McA-RH7777 cells resulted in a 39% increase in [3H]TAG associated with VLDL secretion. Cathepsin B knockdown was accompanied by a 74% increase in cellular LFABP protein levels, but only when cells were exposed to 0.4 mm oleic acid (OA) complexed to BSA. The cathepsin B knockdown and 24-h treatment with OA resulted in increased CD36 expression alone and additively. Co-localization of LFABP and cathepsin B was observed in a distinct Golgi apparatus-like pattern, which required a 1-h OA treatment. Moreover, we observed co-localization of LFABP and apoB, independent of the OA treatment. Overexpression of cathepsin B resulted in decreased OA uptake and VLDL secretion. Co-expression of cathepsin B and cathepsin B-resistant mutant LFABP in McA-RH7777 cells resulted in an increased TAG secretion as compared with cells co-expressing cathepsin B and wildtype LFABP. Together, these data indicate that cathepsin B regulates VLDL secretion and free fatty acid uptake via cleavage of LFABP, which occurs in response to oleic acid exposure.
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Affiliation(s)
- Simeon Thibeaux
- From the Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida 32827
| | - Shaila Siddiqi
- From the Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida 32827
| | - Olga Zhelyabovska
- From the Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida 32827
| | - Faisal Moinuddin
- From the Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida 32827
| | - Michal M Masternak
- From the Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida 32827
| | - Shadab A Siddiqi
- From the Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida 32827
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31
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Choi H, Jin UH, Kang SK, Abekura F, Park JY, Kwon KM, Suh SJ, Cho SH, Ha KT, Lee YC, Chung TW, Kim CH. Monosialyl Ganglioside GM3 Decreases Apolipoprotein B-100 Secretion in Liver Cells. J Cell Biochem 2017; 118:2168-2181. [PMID: 28019668 DOI: 10.1002/jcb.25860] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Accepted: 12/22/2016] [Indexed: 12/13/2022]
Abstract
Some sialic acid-containing glycolipids are known to regulate development of atherosclerosis with accumulated plasma apolipoprotein B-100 (Apo-B)-containing lipoproteins, because Apo-B as an atherogenic apolipoprotein is assembled mainly in VLDL and LDL. Previously, we have elucidated that disialyl GD3 promotes the microsomal triglyceride transfer protein (MTP) gene expression and secretion of triglyceride (TG)-assembled ApoB, claiming the GD3 role in ApoB lipoprotein secretion in liver cells. In the synthetic pathway of gangliosides, GD3 is synthesized by addition of a sialic acid residue to GM3. Thus, there should be some regulatory links between GM3 and GD3. In this study, exogenous and endogenous monosialyl GM3 has been examined how GM3 plays a role in ApoB secretion in Chang liver cells in a view point of MTP and ApoB degradation in the same cells. The level of GM3 ganglioside in the GM3 synthase gene-transfected cells was increased in the cell extract, but not in the medium. In addition, GM3 synthase gene-transfected cells showed a diminished secretion of TG-enriched ApoB with a lower content of TG in the medium. Exogenous GM3 treatment for 24 h exerted a dose dependent inhibitory effect on ApoB secretion together with TG, while a liver-specific albumin was unchanged, indicating that GM3 effect is limited to ApoB secretion. GM3 decreased the mRNA level of MTP gene, too. ApoB protein assembly dysregulated by GM3 indicates the impaired ApoB secretion is caused by a proteasome-dependent pathway. Treatment with small interfering RNAs (siRNAs) decreased ApoB secretion, but GM3-specific antibody did not. These results indicate that plasma membrane associated GM3 inhibits ApoB secretion, lowers development of atherosclerosis by decreasing the secretion of TG-enriched ApoB containing lipoproteins, suggesting that GM3 is an inhibitor of ApoB and TG secretion in liver cells. J. Cell. Biochem. 118: 2168-2181, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Hyunju Choi
- Molecular and Cellular Glycobiology Unit, Department of Biological Science, Sungkyunkwan University, Kyunggi-Do 440-746, Korea
| | - Un-Ho Jin
- Molecular and Cellular Glycobiology Unit, Department of Biological Science, Sungkyunkwan University, Kyunggi-Do 440-746, Korea
| | - Sung-Koo Kang
- Molecular and Cellular Glycobiology Unit, Department of Biological Science, Sungkyunkwan University, Kyunggi-Do 440-746, Korea
| | - Fukushi Abekura
- Molecular and Cellular Glycobiology Unit, Department of Biological Science, Sungkyunkwan University, Kyunggi-Do 440-746, Korea
| | - Jun-Young Park
- Molecular and Cellular Glycobiology Unit, Department of Biological Science, Sungkyunkwan University, Kyunggi-Do 440-746, Korea
| | - Kyung-Min Kwon
- Molecular and Cellular Glycobiology Unit, Department of Biological Science, Sungkyunkwan University, Kyunggi-Do 440-746, Korea.,Research Institute, Davinch-K Co., Ltd., Geumcheon-gu, Seoul 153-719, Korea
| | - Seok-Jong Suh
- Molecular and Cellular Glycobiology Unit, Department of Biological Science, Sungkyunkwan University, Kyunggi-Do 440-746, Korea
| | - Seung-Hak Cho
- Division of Enteric Diseases, Center for Infectious Diseases Research, Korea National Institute of Health, Heungdeok-gu, Cheongju 363-951, Korea
| | - Ki-Tae Ha
- Division of Applied Medicine, School of Korean Medicine, Pusan National University, Yangsan City, Korea
| | - Young-Coon Lee
- Faculty of Medicinal Biotechnology, Dong-A University, Busan 604-714, Korea
| | - Tae-Wook Chung
- Division of Applied Medicine, School of Korean Medicine, Pusan National University, Yangsan City, Korea
| | - Cheorl-Ho Kim
- Molecular and Cellular Glycobiology Unit, Department of Biological Science, Sungkyunkwan University, Kyunggi-Do 440-746, Korea.,Department of Medical Device Management and Research, Samsung Advanced Institute for Health Sciences and Technology (SAIHST), Sungkyunkwan University, Seoul 06351, Korea
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32
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Ronis M, Mercer K, Engi B, Pulliam C, Zimniak P, Hennings L, Shearn C, Badger T, Petersen D. Global Deletion of Glutathione S-Transferase A4 Exacerbates Developmental Nonalcoholic Steatohepatitis. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 187:418-430. [PMID: 27998724 PMCID: PMC5389362 DOI: 10.1016/j.ajpath.2016.10.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 09/16/2016] [Accepted: 10/17/2016] [Indexed: 01/27/2023]
Abstract
We established a mouse model of developmental nonalcoholic steatohepatitis (NASH) by feeding a high polyunsaturated fat liquid diet to female glutathione-S-transferase 4-4 (Gsta4-/-)/peroxisome proliferator activated receptor α (Ppara-/-) double knockout 129/SvJ mice for 12 weeks from weaning. We used it to probe the importance of lipid peroxidation in progression of NASH beyond simple steatosis. Feeding Gsta4-/-/Ppara-/- double-knockout (dKO) mice liquid diets containing corn oil resulted in a percentage fat-dependent increase in steatosis and necroinflammatory injury (P < 0.05). Increasing fat to 70% from 35% resulted in increases in formation of 4-hydroxynonenal protein adducts accompanied by evidence of stellate cell activation, matrix remodeling, and fibrosis (P < 0.05). Comparison of dKO mice with wild-type (Wt) and single knockout mice revealed additive effects of Gsta4-/- and Ppara-/- silencing on steatosis, 4-hydroxynonenal adduct formation, oxidative stress, serum alanine amino transferase, expression of tumor necrosis factor alpha, Il6, interferon mRNA, and liver pathology (P < 0.05). Induction of Cyp2e1 protein by high-fat diet was suppressed in Gsta4-/- and dKO groups (P < 0.05). The dKO mice had similar levels of markers of stellate cell activation and matrix remodeling as Ppara-/- single KO mice. These data suggest that lipid peroxidation products play a role in progression of liver injury to steatohepatitis in NASH produced by high-fat feeding during development but appear less important in development of fibrosis.
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Affiliation(s)
- Martin Ronis
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center-New Orleans, New Orleans, Louisiana.
| | - Kelly Mercer
- Arkansas Children's Nutrition Center, University of Arkansas for Medical Sciences, Little Rock, Arkansas; Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado.
| | - Bridgette Engi
- Department of Laboratory Animal Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Casey Pulliam
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center-New Orleans, New Orleans, Louisiana
| | - Piotr Zimniak
- Department of Pharmacology and Toxicology, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Leah Hennings
- Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Colin Shearn
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Thomas Badger
- Arkansas Children's Nutrition Center, University of Arkansas for Medical Sciences, Little Rock, Arkansas; Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Dennis Petersen
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado
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Walsh MT, Hussain MM. Targeting microsomal triglyceride transfer protein and lipoprotein assembly to treat homozygous familial hypercholesterolemia. Crit Rev Clin Lab Sci 2016; 54:26-48. [PMID: 27690713 DOI: 10.1080/10408363.2016.1221883] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Homozygous familial hypercholesterolemia (HoFH) is a polygenic disease arising from defects in the clearance of plasma low-density lipoprotein (LDL), which results in extremely elevated plasma LDL cholesterol (LDL-C) and increased risk of atherosclerosis, coronary heart disease, and premature death. Conventional lipid-lowering therapies, such as statins and ezetimibe, are ineffective at lowering plasma cholesterol to safe levels in these patients. Other therapeutic options, such as LDL apheresis and liver transplantation, are inconvenient, costly, and not readily available. Recently, lomitapide was approved by the Federal Drug Administration as an adjunct therapy for the treatment of HoFH. Lomitapide inhibits microsomal triglyceride transfer protein (MTP), reduces lipoprotein assembly and secretion, and lowers plasma cholesterol levels by over 50%. Here, we explain the steps involved in lipoprotein assembly, summarize the role of MTP in lipoprotein assembly, explore the clinical and molecular basis of HoFH, and review pre-clinical studies and clinical trials with lomitapide and other MTP inhibitors for the treatment of HoFH. In addition, ongoing research and new approaches underway for better treatment modalities are discussed.
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Affiliation(s)
- Meghan T Walsh
- a School of Graduate Studies, Molecular and Cell Biology Program, State University of New York Downstate Medical Center , Brooklyn , NY , USA.,b Department of Cell Biology , State University of New York Downstate Medical Center , Brooklyn , NY , USA
| | - M Mahmood Hussain
- b Department of Cell Biology , State University of New York Downstate Medical Center , Brooklyn , NY , USA.,c Department of Pediatrics , SUNY Downstate Medical Center , Brooklyn , NY , USA.,d VA New York Harbor Healthcare System , Brooklyn , NY , USA , and.,e Winthrop University Hospital , Mineola , NY , USA
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Mobin MB, Gerstberger S, Teupser D, Campana B, Charisse K, Heim MH, Manoharan M, Tuschl T, Stoffel M. The RNA-binding protein vigilin regulates VLDL secretion through modulation of Apob mRNA translation. Nat Commun 2016; 7:12848. [PMID: 27665711 PMCID: PMC5052685 DOI: 10.1038/ncomms12848] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 08/01/2016] [Indexed: 01/07/2023] Open
Abstract
The liver is essential for the synthesis of plasma proteins and integration of lipid metabolism. While the role of transcriptional networks in these processes is increasingly understood, less is known about post-transcriptional control of gene expression by RNA-binding proteins (RBPs). Here, we show that the RBP vigilin is upregulated in livers of obese mice and in patients with fatty liver disease. By using in vivo, biochemical and genomic approaches, we demonstrate that vigilin controls very-low-density lipoprotein (VLDL) secretion through the modulation of apolipoproteinB/Apob mRNA translation. Crosslinking studies reveal that vigilin binds to CU-rich regions in the mRNA coding sequence of Apob and other proatherogenic secreted proteins, including apolipoproteinC-III/Apoc3 and fibronectin/Fn1. Consequently, hepatic vigilin knockdown decreases VLDL/low-density lipoprotein (LDL) levels and formation of atherosclerotic plaques in Ldlr−/− mice. These studies uncover a role for vigilin as a key regulator of hepatic Apob translation and demonstrate the therapeutic potential of inhibiting vigilin for cardiovascular diseases. RNA-binding proteins (RBP) are an emerging group of post-translational regulators. Here the authors show that the RBP vigilin regulates translation of mRNA encoding for proatherogenic proteins—apoB, apoC-III and fibronectin—representing a potential therapeutic target in cardiovascular diseases.
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Affiliation(s)
- Mehrpouya B Mobin
- Institute of Molecular Health Sciences, ETH Zurich, Otto-Stern Weg 7, 8093 Zurich, Switzerland
| | - Stefanie Gerstberger
- Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, New York 10065, USA
| | - Daniel Teupser
- Institute of Laboratory Medicine, Ludwig-Maximilians-University Munich, Marchioninistr. 15, 81377 Munich, Germany
| | - Benedetta Campana
- Department of Biomedicine and Clinic for Gastroenterology and Hepatology, University Hospital Basel, Hebelstrasse 20, 4031 Basel, Switzerland
| | - Klaus Charisse
- Alnylam Pharmaceuticals, 300 Third Street, Cambridge, Massachusetts 02142, USA
| | - Markus H Heim
- Department of Biomedicine and Clinic for Gastroenterology and Hepatology, University Hospital Basel, Hebelstrasse 20, 4031 Basel, Switzerland
| | - Muthiah Manoharan
- Alnylam Pharmaceuticals, 300 Third Street, Cambridge, Massachusetts 02142, USA
| | - Thomas Tuschl
- Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, New York 10065, USA
| | - Markus Stoffel
- Institute of Molecular Health Sciences, ETH Zurich, Otto-Stern Weg 7, 8093 Zurich, Switzerland
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35
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Costabile BK, Kim YK, Iqbal J, Zuccaro MV, Wassef L, Narayanasamy S, Curley RW, Harrison EH, Hussain MM, Quadro L. β-Apo-10'-carotenoids Modulate Placental Microsomal Triglyceride Transfer Protein Expression and Function to Optimize Transport of Intact β-Carotene to the Embryo. J Biol Chem 2016; 291:18525-35. [PMID: 27402843 DOI: 10.1074/jbc.m116.738336] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Indexed: 11/06/2022] Open
Abstract
β-Carotene is an important source of vitamin A for the mammalian embryo, which depends on its adequate supply to achieve proper organogenesis. In mammalian tissues, β-carotene 15,15'-oxygenase (BCO1) converts β-carotene to retinaldehyde, which is then oxidized to retinoic acid, the biologically active form of vitamin A that acts as a transcription factor ligand to regulate gene expression. β-Carotene can also be cleaved by β-carotene 9',10'-oxygenase (BCO2) to form β-apo-10'-carotenal, a precursor of retinoic acid and a transcriptional regulator per se The mammalian embryo obtains β-carotene from the maternal circulation. However, the molecular mechanisms that enable its transfer across the maternal-fetal barrier are not understood. Given that β-carotene is transported in the adult bloodstream by lipoproteins and that the placenta acquires, assembles, and secretes lipoproteins, we hypothesized that the aforementioned process requires placental lipoprotein biosynthesis. Here we show that β-carotene availability regulates transcription and activity of placental microsomal triglyceride transfer protein as well as expression of placental apolipoprotein B, two key players in lipoprotein biosynthesis. We also show that β-apo-10'-carotenal mediates the transcriptional regulation of microsomal triglyceride transfer protein via hepatic nuclear factor 4α and chicken ovalbumin upstream promoter transcription factor I/II. Our data provide the first in vivo evidence of the transcriptional regulatory activity of β-apocarotenoids and identify microsomal triglyceride transfer protein and its transcription factors as the targets of their action. This study demonstrates that β-carotene induces a feed-forward mechanism in the placenta to enhance the assimilation of β-carotene for proper embryogenesis.
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Affiliation(s)
- Brianna K Costabile
- From the Department of Food Science and Rutgers Center for Lipid Research and New Jersey Institute for Food Nutrition and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - Youn-Kyung Kim
- From the Department of Food Science and Rutgers Center for Lipid Research and New Jersey Institute for Food Nutrition and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - Jahangir Iqbal
- Departments of Cell Biology and Pediatrics, State University of New York (SUNY) Downstate Medical Center, Brooklyn, New York 11203, and
| | - Michael V Zuccaro
- From the Department of Food Science and Rutgers Center for Lipid Research and New Jersey Institute for Food Nutrition and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - Lesley Wassef
- From the Department of Food Science and Rutgers Center for Lipid Research and New Jersey Institute for Food Nutrition and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - Sureshbabu Narayanasamy
- College of Pharmacy and Department of Human Nutrition, The Ohio State University, Columbus, Ohio 43210
| | | | - Earl H Harrison
- Department of Human Nutrition, The Ohio State University, Columbus, Ohio 43210
| | - M Mahmood Hussain
- Departments of Cell Biology and Pediatrics, State University of New York (SUNY) Downstate Medical Center, Brooklyn, New York 11203, and
| | - Loredana Quadro
- From the Department of Food Science and Rutgers Center for Lipid Research and New Jersey Institute for Food Nutrition and Health, Rutgers University, New Brunswick, New Jersey 08901,
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36
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Yanai H, Hirowatari Y, Ito K, Kurosawa H, Tada N, Yoshida H. Understanding of Diabetic Dyslipidemia by Using the Anion-Exchange High Performance Liquid Chromatography Data. J Clin Med Res 2016; 8:424-6. [PMID: 27081430 PMCID: PMC4817584 DOI: 10.14740/jocmr2533w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/03/2016] [Indexed: 11/20/2022] Open
Affiliation(s)
- Hidekatsu Yanai
- Department of Internal Medicine, National Center for Global Health and Medicine Kohnodai Hospital, Chiba, Japan
| | - Yuji Hirowatari
- Laboratory Sciences, Department of Health Sciences, School of Health and Social Service, Saitama Prefectural University, Saitama, Japan
| | - Kumie Ito
- Department of Internal Medicine, Yaesu Sakura Dori Clinic, Tokyo, Japan
| | - Hideo Kurosawa
- Institute of Clinical Medicine and Research, Jikei University School of Medicine, Chiba, Japan; Department of Laboratory Medicine, Inzai General Hospital, Chiba, Japan
| | - Norio Tada
- Institute of Clinical Medicine and Research, Jikei University School of Medicine, Chiba, Japan
| | - Hiroshi Yoshida
- Institute of Clinical Medicine and Research, Jikei University School of Medicine, Chiba, Japan; Department of Internal Medicine, Jikei University Kashiwa Hospital, Chiba, Japan; Department of Laboratory Medicine, Jikei University Kashiwa Hospital, Chiba, Japan
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37
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Llombart V, García-Berrocoso T, Bustamante A, Giralt D, Rodriguez-Luna D, Muchada M, Penalba A, Boada C, Hernández-Guillamon M, Montaner J. Plasmatic retinol-binding protein 4 and glial fibrillary acidic protein as biomarkers to differentiate ischemic stroke and intracerebral hemorrhage. J Neurochem 2015; 136:416-24. [DOI: 10.1111/jnc.13419] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Revised: 09/30/2015] [Accepted: 10/09/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Víctor Llombart
- Neurovascular Research Laboratory; Vall d'Hebron Institute of Research (VHIR); Universitat Autonoma de Barcelona; Barcelona Spain
| | - Teresa García-Berrocoso
- Neurovascular Research Laboratory; Vall d'Hebron Institute of Research (VHIR); Universitat Autonoma de Barcelona; Barcelona Spain
| | - Alejandro Bustamante
- Neurovascular Research Laboratory; Vall d'Hebron Institute of Research (VHIR); Universitat Autonoma de Barcelona; Barcelona Spain
| | - Dolors Giralt
- Neurovascular Research Laboratory; Vall d'Hebron Institute of Research (VHIR); Universitat Autonoma de Barcelona; Barcelona Spain
| | - David Rodriguez-Luna
- Neurovascular Unit; Department of Neurology; Vall d'Hebron University Hospital; Barcelona Spain
| | - Marian Muchada
- Neurovascular Unit; Department of Neurology; Vall d'Hebron University Hospital; Barcelona Spain
| | - Anna Penalba
- Neurovascular Research Laboratory; Vall d'Hebron Institute of Research (VHIR); Universitat Autonoma de Barcelona; Barcelona Spain
| | - Cristina Boada
- Neurovascular Research Laboratory; Vall d'Hebron Institute of Research (VHIR); Universitat Autonoma de Barcelona; Barcelona Spain
| | - Mar Hernández-Guillamon
- Neurovascular Research Laboratory; Vall d'Hebron Institute of Research (VHIR); Universitat Autonoma de Barcelona; Barcelona Spain
| | - Joan Montaner
- Neurovascular Research Laboratory; Vall d'Hebron Institute of Research (VHIR); Universitat Autonoma de Barcelona; Barcelona Spain
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38
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Role of Tribbles Pseudokinase 1 (TRIB1) in human hepatocyte metabolism. Biochim Biophys Acta Mol Basis Dis 2015; 1862:223-32. [PMID: 26657055 DOI: 10.1016/j.bbadis.2015.12.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 11/18/2015] [Accepted: 12/01/2015] [Indexed: 01/23/2023]
Abstract
Genome-wide association studies for plasma triglycerides and hepatic steatosis identified a risk locus on chromosome 8q24 close to the TRIB1 gene, encoding Tribbles Pseudokinase 1 (TRIB1). In previous studies conducted in murine models, hepatic over-expression of Trib1 was shown to increase fatty acid oxidation and decrease triglyceride synthesis whereas Trib1 knockdown mice exhibited hypertriglyceridemia. Here we have examined the impact of TRIB1 suppression in human and mouse hepatocytes. Examination of a panel of lipid regulator transcripts revealed species-specific effects, prompting us to focus on human models for the remainder of the study. Acute knockdown of TRIB1 in human primary hepatocytes resulted in decreased expression of MTTP and APOB, required for very low density lipoprotein (VLDL) assembly although particle secretion was not significantly affected. A parallel analysis performed in HepG2 revealed reduced MTTP, but not APOB, protein as a result of TRIB1 suppression. Global gene expression changes of human primary hepatocytes upon TRIB1 suppression were analyzed by clustering algorithms and found to be consistent with dysregulation of several pathways fundamental to liver function, including altered CEBPA and B transcript levels and impaired glucose handling. Indeed, TRIB1 expression in HepG2 cells was found to be inversely proportional to glucose concentration. Lastly TRIB1 downregulation in primary hepatocytes was associated with suppression of the HNF4A axis. In HepG2 cells, TRIB1 suppression resulted in reduced HNF4A protein levels while HNF4A suppression increased TRIB1 expression. Taken together these studies reveal an important role for TRIB1 in human hepatocyte biology.
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39
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Evaluating computational models of cholesterol metabolism. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:1360-76. [DOI: 10.1016/j.bbalip.2015.05.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 05/08/2015] [Accepted: 05/26/2015] [Indexed: 02/02/2023]
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40
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Stanhope KL. Sugar consumption, metabolic disease and obesity: The state of the controversy. Crit Rev Clin Lab Sci 2015; 53:52-67. [PMID: 26376619 DOI: 10.3109/10408363.2015.1084990] [Citation(s) in RCA: 397] [Impact Index Per Article: 44.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The impact of sugar consumption on health continues to be a controversial topic. The objective of this review is to discuss the evidence and lack of evidence that allows the controversy to continue, and why resolution of the controversy is important. There are plausible mechanisms and research evidence that supports the suggestion that consumption of excess sugar promotes the development of cardiovascular disease (CVD) and type 2 diabetes (T2DM) both directly and indirectly. The direct pathway involves the unregulated hepatic uptake and metabolism of fructose, leading to liver lipid accumulation, dyslipidemia, decreased insulin sensitivity and increased uric acid levels. The epidemiological data suggest that these direct effects of fructose are pertinent to the consumption of the fructose-containing sugars, sucrose and high fructose corn syrup (HFCS), which are the predominant added sugars. Consumption of added sugar is associated with development and/or prevalence of fatty liver, dyslipidemia, insulin resistance, hyperuricemia, CVD and T2DM, often independent of body weight gain or total energy intake. There are diet intervention studies in which human subjects exhibited increased circulating lipids and decreased insulin sensitivity when consuming high sugar compared with control diets. Most recently, our group has reported that supplementing the ad libitum diets of young adults with beverages containing 0%, 10%, 17.5% or 25% of daily energy requirement (Ereq) as HFCS increased lipid/lipoprotein risk factors for CVD and uric acid in a dose-response manner. However, un-confounded studies conducted in healthy humans under a controlled, energy-balanced diet protocol that enables determination of the effects of sugar with diets that do not allow for body weight gain are lacking. Furthermore, recent reports conclude that there are no adverse effects of consuming beverages containing up to 30% Ereq sucrose or HFCS, and the conclusions from several meta-analyses suggest that fructose has no specific adverse effects relative to any other carbohydrate. Consumption of excess sugar may also promote the development of CVD and T2DM indirectly by causing increased body weight and fat gain, but this is also a topic of controversy. Mechanistically, it is plausible that fructose consumption causes increased energy intake and reduced energy expenditure due to its failure to stimulate leptin production. Functional magnetic resonance imaging (fMRI) of the brain demonstrates that the brain responds differently to fructose or fructose-containing sugars compared with glucose or aspartame. Some epidemiological studies show that sugar consumption is associated with body weight gain, and there are intervention studies in which consumption of ad libitum high-sugar diets promoted increased body weight gain compared with consumption of ad libitum low- sugar diets. However, there are no studies in which energy intake and weight gain were compared in subjects consuming high or low sugar, blinded, ad libitum diets formulated to ensure both groups consumed a comparable macronutrient distribution and the same amounts of fiber. There is also little data to determine whether the form in which added sugar is consumed, as beverage or as solid food, affects its potential to promote weight gain. It will be very challenging to obtain the funding to conduct the clinical diet studies needed to address these evidence gaps, especially at the levels of added sugar that are commonly consumed. Yet, filling these evidence gaps may be necessary for supporting the policy changes that will help to turn the food environment into one that does not promote the development of obesity and metabolic disease.
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Affiliation(s)
- Kimber L Stanhope
- a Department of Molecular Biosciences , School of Veterinary Medicine and.,b Department of Nutrition , University of California , Davis , CA , USA
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41
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Li J, Inoue J, Choi JM, Nakamura S, Yan Z, Fushinobu S, Kamada H, Kato H, Hashidume T, Shimizu M, Sato R. Identification of the Flavonoid Luteolin as a Repressor of the Transcription Factor Hepatocyte Nuclear Factor 4α. J Biol Chem 2015; 290:24021-35. [PMID: 26272613 DOI: 10.1074/jbc.m115.645200] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Indexed: 01/14/2023] Open
Abstract
Hepatocyte nuclear factor 4α (HNF4α) is a nuclear receptor that regulates the expression of genes involved in the secretion of apolipoprotein B (apoB)-containing lipoproteins and in glucose metabolism. In the present study, we identified a naturally occurring flavonoid, luteolin, as a repressor of HNF4α by screening for effectors of the human microsomal triglyceride transfer protein (MTP) promoter. Luciferase reporter gene assays revealed that the activity of the MTP gene promoter was suppressed by luteolin and that the mutation of HNF4α-binding element abolished luteolin responsiveness. Luteolin treatment caused a significant decrease in the mRNA levels of HNF4α target genes in HepG2 cells and inhibited apoB-containing lipoprotein secretion in HepG2 and differentiated Caco2 cells. The interaction between luteolin and HNF4α was demonstrated using absorption spectrum analysis and luteolin-immobilized beads. Luteolin did not affect the DNA binding of HNF4α to the promoter region of its target genes but suppressed the acetylation level of histone H3 in the promoter region of certain HNF4α target genes. Short term treatment of mice with luteolin significantly suppressed the expression of HNF4α target genes in the liver. In addition, long term treatment of mice with luteolin significantly suppressed their diet-induced obesity and improved their serum glucose and lipid parameters. Importantly, long term luteolin treatment lowered serum VLDL and LDL cholesterol and serum apoB protein levels, which was not accompanied by fat accumulation in the liver. These results suggest that the flavonoid luteolin ameliorates an atherogenic lipid profile in vivo that is likely to be mediated through the inactivation of HNF4α.
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Affiliation(s)
- Juan Li
- From the Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 1-1-1 Yayoi, 113-8657, Japan
| | - Jun Inoue
- From the Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 1-1-1 Yayoi, 113-8657, Japan,
| | - Jung-Min Choi
- From the Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 1-1-1 Yayoi, 113-8657, Japan
| | - Shugo Nakamura
- the Department of Biotechnology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 113-8657, Japan
| | - Zhen Yan
- the Department of Biotechnology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 113-8657, Japan
| | - Shinya Fushinobu
- the Department of Biotechnology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 113-8657, Japan
| | - Haruhiko Kamada
- the Laboratory of Biopharmaceutical Research, National Institute of Biomedical Innovation, Osaka 567-0085, Japan
| | - Hisanori Kato
- From the Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 1-1-1 Yayoi, 113-8657, Japan, the Corporate Sponsored Research Program "Food for Life," Organization for Interdisciplinary Research Projects, University of Tokyo, Tokyo, 113-8657, Japan, and
| | - Tsutomu Hashidume
- the Institute of Gerontology, University of Tokyo, Tokyo 113-8656, Japan
| | - Makoto Shimizu
- From the Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 1-1-1 Yayoi, 113-8657, Japan
| | - Ryuichiro Sato
- From the Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 1-1-1 Yayoi, 113-8657, Japan,
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Hepatocyte-Specific Depletion of UBXD8 Induces Periportal Steatosis in Mice Fed a High-Fat Diet. PLoS One 2015; 10:e0127114. [PMID: 25970332 PMCID: PMC4430229 DOI: 10.1371/journal.pone.0127114] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Accepted: 04/10/2015] [Indexed: 12/19/2022] Open
Abstract
We showed previously that UBXD8 plays a key role in proteasomal degradation of lipidated ApoB in hepatocarcinoma cell lines. In the present study, we aimed to investigate the functions of UBXD8 in liver in vivo. For this purpose, hepatocyte-specific UBXD8 knockout (UBXD8-LKO) mice were generated. They were fed with a normal or high-fat diet, and the phenotypes were compared with those of littermate control mice. Hepatocytes obtained from UBXD8-LKO and control mice were analyzed in culture. After 26 wk of a high-fat diet, UBXD8-LKO mice exhibited macrovesicular steatosis in the periportal area and microvesicular steatosis in the perivenular area, whereas control mice exhibited steatosis only in the perivenular area. Furthermore, UBXD8-LKO mice on a high-fat diet had significantly lower concentrations of serum triglyceride and VLDL than control mice. A Triton WR-1339 injection study revealed that VLDL secretion from hepatocytes was reduced in UBXD8-LKO mice. The decrease of ApoB secretion upon UBXD8 depletion was recapitulated in cultured primary hepatocytes. Accumulation of lipidated ApoB in lipid droplets was observed only in UBXD8-null hepatocytes. The results showed that depletion of UBXD8 in hepatocytes suppresses VLDL secretion, and could lead to periportal steatosis when mice are fed a high-fat diet. This is the first demonstration that an abnormality in the intracellular ApoB degradation mechanism can cause steatosis, and provides a useful model for periportal steatosis, which occurs in several human diseases.
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Lu L, Chen Y, Wang Z, Li X, Chen W, Tao Z, Shen J, Tian Y, Wang D, Li G, Chen L, Chen F, Fang D, Yu L, Sun Y, Ma Y, Li J, Wang J. The goose genome sequence leads to insights into the evolution of waterfowl and susceptibility to fatty liver. Genome Biol 2015; 16:89. [PMID: 25943208 PMCID: PMC4419397 DOI: 10.1186/s13059-015-0652-y] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 04/13/2015] [Indexed: 12/19/2022] Open
Abstract
Background Geese were domesticated over 6,000 years ago, making them one of the first domesticated poultry. Geese are capable of rapid growth, disease resistance, and high liver lipid storage capacity, and can be easily fed coarse fodder. Here, we sequence and analyze the whole-genome sequence of an economically important goose breed in China and compare it with that of terrestrial bird species. Results A draft sequence of the whole-goose genome was obtained by shotgun sequencing, and 16,150 protein-coding genes were predicted. Comparative genomics indicate that significant differences occur between the goose genome and that of other terrestrial bird species, particularly regarding major histocompatibility complex, Myxovirus resistance, Retinoic acid-inducible gene I, and other genes related to disease resistance in geese. In addition, analysis of transcriptome data further reveals a potential molecular mechanism involved in the susceptibility of geese to fatty liver disease and its associated symptoms, including high levels of unsaturated fatty acids and low levels of cholesterol. The results of this study show that deletion of the goose lep gene might be the result of positive selection, thus allowing the liver to adopt energy storage mechanisms for long-distance migration. Conclusions This is the first report describing the complete goose genome sequence and contributes to genomic resources available for studying aquatic birds. The findings in this study are useful not only for genetic breeding programs, but also for studying lipid metabolism disorders. Electronic supplementary material The online version of this article (doi:10.1186/s13059-015-0652-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lizhi Lu
- Institute of Animal Husbandry and Veterinary Science, Zhejiang Academy of Agricultural Sciences, Hangzhou, China.
| | - Yan Chen
- BGI-Shenzhen, Shenzhen, 518083, China.
| | - Zhuo Wang
- BGI-Shenzhen, Shenzhen, 518083, China.
| | | | - Weihu Chen
- Institute of Zhedong White Goose, Xianshan, China.
| | - Zhengrong Tao
- Institute of Animal Husbandry and Veterinary Science, Zhejiang Academy of Agricultural Sciences, Hangzhou, China.
| | - Junda Shen
- Institute of Animal Husbandry and Veterinary Science, Zhejiang Academy of Agricultural Sciences, Hangzhou, China.
| | - Yong Tian
- Institute of Animal Husbandry and Veterinary Science, Zhejiang Academy of Agricultural Sciences, Hangzhou, China.
| | - Deqian Wang
- Institute of Animal Husbandry and Veterinary Science, Zhejiang Academy of Agricultural Sciences, Hangzhou, China.
| | - Guoqin Li
- Institute of Animal Husbandry and Veterinary Science, Zhejiang Academy of Agricultural Sciences, Hangzhou, China.
| | - Li Chen
- Institute of Animal Husbandry and Veterinary Science, Zhejiang Academy of Agricultural Sciences, Hangzhou, China.
| | - Fang Chen
- Institute of Animal Husbandry and Veterinary Science, Zhejiang Academy of Agricultural Sciences, Hangzhou, China.
| | | | - Lili Yu
- BGI-Tech, BGI-Shenzhen, Shenzhen, 518083, China.
| | - Yudong Sun
- BGI-Tech, BGI-Shenzhen, Shenzhen, 518083, China.
| | - Yong Ma
- BGI-Shenzhen, Shenzhen, 518083, China.
| | - Jinjun Li
- Institute of Animal Husbandry and Veterinary Science, Zhejiang Academy of Agricultural Sciences, Hangzhou, China.
| | - Jun Wang
- BGI-Shenzhen, Shenzhen, 518083, China. .,Department of Biology, University of Copenhagen, Copenhagen, Denmark. .,King Abdulaziz University, Jeddah, Saudi Arabia.
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Li J, Matye DJ, Li T. Insulin resistance induces posttranslational hepatic sortilin 1 degradation in mice. J Biol Chem 2015; 290:11526-36. [PMID: 25805502 DOI: 10.1074/jbc.m115.641225] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Indexed: 12/22/2022] Open
Abstract
Insulin promotes hepatic apolipoprotein B100 (apoB100) degradation, whereas insulin resistance is a major cause of hepatic apoB100/triglyceride overproduction in type 2 diabetes. The cellular trafficking receptor sortilin 1 (Sort1) was recently identified to transport apoB100 to the lysosome for degradation in the liver and thus regulate plasma cholesterol and triglyceride levels. Genetic variation of SORT1 was strongly associated with cardiovascular disease risk in humans. The major goal of this study is to investigate the effect and molecular mechanism of insulin regulation of Sort1. Results showed that insulin induced Sort1 protein, but not mRNA, in AML12 cells. Treatment of PI3K or AKT inhibitors decreased Sort1 protein, whereas expression of constitutively active AKT induced Sort1 protein in AML12 cells. Consistently, hepatic Sort1 was down-regulated in diabetic mice, which was partially restored after the administration of the insulin sensitizer metformin. LC-MS/MS analysis further revealed that serine phosphorylation of Sort1 protein was required for insulin induction of Sort1 in a casein kinase 2-dependent manner and that inhibition of PI3K signaling or prevention of Sort1 phosphorylation accelerated proteasome-dependent Sort1 degradation. Administration of a PI3K inhibitor to mice decreased hepatic Sort1 protein and increased plasma cholesterol and triglyceride levels. Adenovirus-mediated overexpression of Sort1 in the liver prevented PI3K inhibitor-induced Sort1 down-regulation and decreased plasma triglyceride but had no effect on plasma cholesterol in mice. This study identified Sort1 as a novel target of insulin signaling and suggests that Sort1 may play a role in altered hepatic apoB100 metabolism in insulin-resistant conditions.
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Affiliation(s)
- Jibiao Li
- From the Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas 66160
| | - David J Matye
- From the Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas 66160
| | - Tiangang Li
- From the Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas 66160
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45
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Han Y, Lin M, Wang X, Guo K, Wang S, Sun M, Wang J, Han X, Fu T, Hu Y, Fu J. Basis of aggravated hepatic lipid metabolism by chronic stress in high-fat diet-fed rat. Endocrine 2015; 48:483-92. [PMID: 24895043 DOI: 10.1007/s12020-014-0307-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 05/16/2014] [Indexed: 01/22/2023]
Abstract
Our previous study has demonstrated that long-term stress, known as chronic stress (CS), can aggravate nonalcoholic fatty liver disease in high-fat diet (HFD)-fed rat. In this study, we tried to figure out which lipid metabolic pathways were impacted by CS in the HFD-fed rat. Male Sprague-Dawley rats (6 weeks of age, n = 8 per group) were fed with either standard diet or HFD with or without CS exposure for 8 weeks. Hepatic lipidosis, biochemical, hormonal, and lipid profile markers in serum and liver, and enzymes involved in de novo lipogenesis (DNL) of fatty acids (FAs) and cholesterol, β-oxidation, FAs uptake, triglycerides synthesis, and very low-density lipoprotein (VLDL) assembly in the liver were detected. CS exposure reduced hepatic lipidosis but further elevated hepatic VLDL content with aggravated dyslipidemia in the HFD-fed rats. There was a synergism between CS and HFD on VLDL production and dyslipidemia. PCR and western blot assays showed that CS exposure significantly promoted hepatic VLDL assembly in rats, especially in the HFD-fed rats, while it had little impact on DNL, β-oxidation, FAs uptake, and triglycerides synthesis in the HFD-fed rats. This phenomenon was in accordance with elevated serum glucocorticoid level. The critical influence of CS exposure on hepatic lipid metabolism in the HFD-fed rats is VLDL assembly which might be regulated by glucocorticoid.
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Affiliation(s)
- Ying Han
- Department of Physiology, China Pharmaceutical University, 639 Long Mian Road, Nanjing, 211198, Jiangsu Province, China
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Abstract
Hypertriglyceridemia (HTG) is a highly prevalent condition that is associated with increased cardiovascular disease risk. HTG may arise as a result of defective metabolism of triglyceride-rich lipoproteins and their remnants, ie, impaired clearance, or increased production, or both. Current categorization of HTG segregates primary and secondary cases, implying genetic and nongenetic causes for each category. Many common and rare variants of the genes encoding factors involved in these pathways have been identified. Although monogenic forms of HTG do occur, most cases are polygenic and often coexist with nongenetic conditions. Cumulative, multiple genetic variants can increase the risks for HTG, whereas environmental and lifestyle factors can force expression of a dyslipidemic phenotype in a genetically susceptible person. HTG states are therefore best viewed as a complex phenotype resulting from the interaction of cumulated multiple susceptibility genes and environmental stressors. In view of the heterogeneity of the HTG states, the absence of a unifying metabolic or genetic abnormality, overlap with the metabolic syndrome and other features of insulin resistance, and evidence in some patients that accumulation of numerous small-effect genetic variants determines whether an individual is susceptible to HTG only or to HTG plus elevated low-density lipoprotein cholesterol, we propose that the diagnosis of primary HTG and further delineation of familial combined hyperlipidemia from familial HTG is neither feasible nor clinically relevant at the present time. The hope is that with greater understanding of genetic and environmental causes and their interaction, therapy can be intelligently targeted in the future.
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Affiliation(s)
- Gary F Lewis
- Departments of Medicine and Physiology and the Banting and Best Diabetes Centre (G.F.L., C.X.), University of Toronto, Toronto, Ontario, Canada M5G 2C4; and Robarts Research Institute (R.A.H.), Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada N6A 5B7
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47
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da Silva RP, Kelly KB, Leonard KA, Jacobs RL. Creatine reduces hepatic TG accumulation in hepatocytes by stimulating fatty acid oxidation. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:1639-46. [PMID: 25205520 DOI: 10.1016/j.bbalip.2014.09.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 08/15/2014] [Accepted: 09/02/2014] [Indexed: 12/22/2022]
Abstract
Non-alcoholic fatty liver disease encompasses a wide spectrum of liver damage including steatosis, non-alcoholic steatohepatitis, fibrosis and cirrhosis. We have previously reported that creatine supplementation prevents hepatic steatosis and lipid peroxidation in rats fed a high-fat diet. In this study, we employed oleate-treated McArdle RH-7777 rat hepatoma cells to investigate the role of creatine in regulating hepatic lipid metabolism. Creatine, but not structural analogs, reduced cellular TG accumulation in a dose-dependent manner. Incubating cells with the pan-lipase inhibitor diethyl p-nitrophenylphosphate (E600) did not diminish the effect of creatine, demonstrating that the TG reduction brought about by creatine does not depend on lipolysis. Radiolabeled tracer experiments indicate that creatine increases fatty acid oxidation and TG secretion. In line with increased fatty acid oxidation, mRNA analysis revealed that creatine-treated cells had increased expression of PPARα and several of its transcriptional targets. Taken together, this study provides direct evidence that creatine reduces lipid accumulation in hepatocytes by the stimulation of fatty acid oxidation and TG secretion.
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Affiliation(s)
- Robin P da Silva
- Metabolic and Cardiovascular Diseases Laboratory, Group on the Molecular and Cell Biology of Lipids, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Karen B Kelly
- Metabolic and Cardiovascular Diseases Laboratory, Group on the Molecular and Cell Biology of Lipids, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Kelly-Ann Leonard
- Metabolic and Cardiovascular Diseases Laboratory, Group on the Molecular and Cell Biology of Lipids, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - René L Jacobs
- Metabolic and Cardiovascular Diseases Laboratory, Group on the Molecular and Cell Biology of Lipids, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada.
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48
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Klawitter J, Bek S, Zakaria M, Zeng C, Hornberger A, Gilbert R, Shokati T, Klawitter J, Christians U, Boernsen KO. Fatty acid desaturation index in human plasma: comparison of different analytical methodologies for the evaluation of diet effects. Anal Bioanal Chem 2014; 406:6399-408. [PMID: 25116600 DOI: 10.1007/s00216-014-8020-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2014] [Revised: 06/30/2014] [Accepted: 07/04/2014] [Indexed: 12/14/2022]
Abstract
Stearoyl-CoA desaturase 1 (SCD1) plays a role in the development of obesity and related conditions, such as insulin resistance, and potentially also in neurological and heart diseases. The activity of SCD1 can be monitored using the desaturation index (DI), the ratio of product (16:1n-7 and 18:1n-9) to precursor (16:0 and 18:0) fatty acids. Here, different analytical strategies were applied to identify the method which best supports SCD1 biology. A novel effective approach was the use of the SCD1-independent fatty acid (16:1n-10) as a negative control. The first approach was based on a simple extraction followed by neutral loss triglyceride fatty acid analysis. The second approach was based on the saponification of triglycerides followed by fatty acid analysis (specific for the position of the double bond within monounsaturated fatty acids (MUFAs)). In addition to the analytical LC-MS assays, different matrices (plasma total triglyceride fraction and the very low-density lipoprotein (VLDL) fraction) were investigated to identify the best for studying changes in SCD1 activity. Samples from volunteers on a high-carbohydrate diet were analyzed. Both ultra HPLC (UHPLC)-MS-based assays showed acceptable accuracies (75-125% of nominal) and precisions (<20%) for the analysis of DI-specific fatty acids in VLDL and plasma. The most specific assay for the analysis of the liver SCD activity was then validated for specificity and selectivity, intra- and interday accuracy and precision, matrix effects, dilution effects, and analyte stability. After 3 days of high-carbohydrate diet, only the specific fatty acids in human plasma VLDL showed a significant increase in DI and associated SCD1 activity.
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Affiliation(s)
- Jost Klawitter
- iC42 Integrated Solutions in Systems Biology, University of Colorado, Aurora, CO, 80045-7503, USA,
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Cruz-Garcia L, Schlegel A. Lxr-driven enterocyte lipid droplet formation delays transport of ingested lipids. J Lipid Res 2014; 55:1944-58. [PMID: 25030662 DOI: 10.1194/jlr.m052845] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Liver X receptors (Lxrs) are master regulators of cholesterol catabolism, driving the elimination of cholesterol from the periphery to the lumen of the intestine. Development of pharmacological agents to activate Lxrs has been hindered by synthetic Lxr agonists' induction of hepatic lipogenesis and hypertriglyceridemia. Elucidating the function of Lxrs in regulating enterocyte lipid handling might identify novel aspects of lipid metabolism that are pharmacologically amenable. We took a genetic approach centered on the single Lxr gene nr1h3 in zebrafish to study the role of Lxr in enterocyte lipid metabolism. Loss of nr1h3 function causes anticipated gene regulatory changes and cholesterol intolerance, collectively reflecting high evolutionary conservation of zebrafish Lxra function. Intestinal nr1h3 activation delays transport of absorbed neutral lipids, with accumulation of neutral lipids in enterocyte cytoplasmic droplets. This delay in transport of ingested neutral lipids protects animals from hypercholesterolemia and hepatic steatosis induced by a high-fat diet. On a gene regulatory level, Lxra induces expression of acsl3a, which encodes acyl-CoA synthetase long-chain family member 3a, a lipid droplet-anchored protein that directs fatty acyl chains into lipids. Forced overexpression of acls3a in enterocytes delays, in part, the appearance of neutral lipids in the vasculature of zebrafish larvae. Activation of Lxr in the intestine cell-autonomously regulates the rate of delivery of absorbed lipids by inducting a temporary lipid intestinal droplet storage depot.
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Affiliation(s)
- Lourdes Cruz-Garcia
- University of Utah Molecular Medicine (U2M2) Program,University of Utah, Salt Lake City, UT 84112 Department of Internal Medicine, Division of Endocrinology, Metabolism, and Diabetes,University of Utah, Salt Lake City, UT 84112
| | - Amnon Schlegel
- University of Utah Molecular Medicine (U2M2) Program,University of Utah, Salt Lake City, UT 84112 Department of Internal Medicine, Division of Endocrinology, Metabolism, and Diabetes,University of Utah, Salt Lake City, UT 84112 Department of Biochemistry, School of Medicine, University of Utah, Salt Lake City, UT 84112
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50
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Kondo Y, Masutomi H, Noda Y, Ozawa Y, Takahashi K, Handa S, Maruyama N, Shimizu T, Ishigami A. Senescence marker protein-30/superoxide dismutase 1 double knockout mice exhibit increased oxidative stress and hepatic steatosis. FEBS Open Bio 2014; 4:522-32. [PMID: 25003023 PMCID: PMC4081155 DOI: 10.1016/j.fob.2014.05.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 04/25/2014] [Accepted: 05/21/2014] [Indexed: 12/27/2022] Open
Abstract
We generated SMP30/SOD1-double knockout (DKO) mice for oxidative stress research. SMP30/SOD1-DKO mice showed low levels of ascorbic acid and premature death. SMP30/SOD1-DKO mice exhibited high levels of oxidative stress and liver injury. SMP30/SOD1-DKO mice manifest hepatic steatosis due to decreased levels of Apolipoprotein B.
Superoxide dismutase 1 (SOD1) is an antioxidant enzyme that converts superoxide anion radicals into hydrogen peroxide and molecular oxygen. The senescence marker protein-30 (SMP30) is a gluconolactonase that functions as an antioxidant protein in mammals due to its involvement in ascorbic acid (AA) biosynthesis. SMP30 also participates in Ca2+ efflux by activating the calmodulin-dependent Ca2+-pump. To reveal the role of oxidative stress in lipid metabolism defects occurring in non-alcoholic fatty liver disease pathogenesis, we generated SMP30/SOD1-double knockout (SMP30/SOD1-DKO) mice and investigated their survival curves, plasma and hepatic lipid profiles, amounts of hepatic oxidative stress, and hepatic protein levels expressed by genes related to lipid metabolism. While SMP30/SOD1-DKO pups had no growth retardation by 14 days of age, they did have low plasma and hepatic AA levels. Thereafter, 39% and 53% of male and female pups died by 15–24 and 89 days of age, respectively. Compared to wild type, SMP30-KO and SOD1-KO mice, by 14 days SMP30/SOD1-DKO mice exhibited: (1) higher plasma levels of triglyceride and aspartate aminotransferase; (2) severe accumulation of hepatic triglyceride and total cholesterol; (3) higher levels of superoxide anion radicals and thiobarbituric acid reactive substances in livers; and (4) decreased mRNA and protein levels of Apolipoprotein B (ApoB) in livers – ApoB is an essential component of VLDL secretion. These results suggest that high levels of oxidative stress due to concomitant deficiency of SMP30 and/or AA, and SOD1 cause abnormal plasma lipid metabolism, hepatic lipid accumulation and premature death resulting from impaired VLDL secretion.
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Key Words
- AA, l-ascorbic acid
- AST, aspartate aminotransferase
- ApoB, Apolipoprotein B
- Ascorbic acid
- DHA, dehydroascorbic acid
- DHE, dihydroethidium
- DKO, double knockout
- EDTA, ethylenediaminetetraacetic acid
- FFA, free fatty acid
- Grp78, glucose-regulated protein 78 kDa
- KO, knockout
- MTP, microsomal triglyceride transfer protein
- NAFLD, non-alcoholic fatty liver disease
- NASH, non-alcoholic steatohepatitis
- Non-alcoholic fatty liver disease
- PL, phospholipid
- PPARα, peroxisome proliferator-activated receptor-α
- Reactive oxygen species
- SDS, sodium dodecyl sulfate
- SMP30
- SMP30, senescence marker protein-30
- SOD, superoxide dismutase
- SOD1
- SREBP, sterol regulatory element binding protein
- T-cho, total cholesterol
- TBARS, thiobarbituric acid reactive substances
- TG, triglyceride
- VLDL, very low-density lipoprotein
- qPCR, quantitative real-time polymerase chain reaction
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Affiliation(s)
- Yoshitaka Kondo
- Molecular Regulation of Aging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan
| | - Hirofumi Masutomi
- Molecular Regulation of Aging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan
| | - Yoshihiro Noda
- Molecular Regulation of Aging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan
| | - Yusuke Ozawa
- Department of Advanced Aging Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan
| | - Keita Takahashi
- Molecular Regulation of Aging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan
| | - Setsuko Handa
- Molecular Regulation of Aging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan
| | - Naoki Maruyama
- Molecular Regulation of Aging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan
| | - Takahiko Shimizu
- Department of Advanced Aging Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan
| | - Akihito Ishigami
- Molecular Regulation of Aging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan
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