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Ansari A, Yadav PK, Valmiki S, Laine A, Rimbert A, Islam S, Osman I, Najafi-Shoushtari SH, Hussain MM. MicroRNA-615-3p decreases apo B expression in human liver cells. J Lipid Res 2024; 65:100659. [PMID: 39332527 DOI: 10.1016/j.jlr.2024.100659] [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: 02/23/2024] [Revised: 09/17/2024] [Accepted: 09/23/2024] [Indexed: 09/29/2024] Open
Abstract
Plasma lipids are mainly carried in apolipoprotein B (apoB) containing lipoproteins. High levels of these lipoproteins are associated with several metabolic diseases and lowering their plasma levels is associated with reduced incidence of atherosclerotic cardiovascular disease. MicroRNAs (miRs) are small non-coding RNAs that reduce the protein expression of their target mRNAs and are potential therapeutic agents. Here, we identified a novel miR-615-3p that interacts with human 3'-UTR of apoB mRNA, induces post-transcriptional mRNA degradation, and reduces cellular and secreted apoB100 in human hepatoma Huh-7 cells. Reducing cellular miR-615-3p levels by CRISPR-sgRNA increased cellular and secreted apoB100 indicating endogenous miR regulates apoB expression. Overexpression of miR-615-3p along with or without palmitic acid treatment decreased cellular and media apoB and increased cellular triglyceride levels without inducing endoplasmic reticulum stress. These studies have identified miR-615-3p as a negative regulator of apoB expression in human liver-derived cells. It is likely that there are more miRs that regulate apoB-containing lipoprotein assembly and secretion. Discovery of additional miRs may uncover novel mechanisms that control lipoprotein assembly and secretion.
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Affiliation(s)
- Abulaish Ansari
- Department of Foundations of Medicine, New York University Grossman Long Island School of Medicine, Mineola, NY, USA; Department of Cell and Developmental Biology, Weill Cornell Medicine, New York, NY, USA; Department of Research, Weill Cornell Medicine-Qatar, Qatar Foundation, Education City, Doha, Qatar
| | - Pradeep Kumar Yadav
- Department of Foundations of Medicine, New York University Grossman Long Island School of Medicine, Mineola, NY, USA; Department of Botany, Faculty of Science, University of Allahabad, Prayagraj, India
| | - Swati Valmiki
- Department of Foundations of Medicine, New York University Grossman Long Island School of Medicine, Mineola, NY, USA
| | - Antoine Laine
- Nantes Université, CNRS, INSERM, l'institut du thorax, Nantes, France
| | - Antoine Rimbert
- Nantes Université, CNRS, INSERM, l'institut du thorax, Nantes, France
| | - Shahidul Islam
- Department of Foundations of Medicine, New York University Grossman Long Island School of Medicine, Mineola, NY, USA
| | - Iman Osman
- Department of Medicine, New York University Langone Medical Center, New York, NY, USA
| | - S Hani Najafi-Shoushtari
- Department of Cell and Developmental Biology, Weill Cornell Medicine, New York, NY, USA; Department of Research, Weill Cornell Medicine-Qatar, Qatar Foundation, Education City, Doha, Qatar
| | - M Mahmood Hussain
- Department of Foundations of Medicine, New York University Grossman Long Island School of Medicine, Mineola, NY, USA; Research Department, New York Harbor Healthcare System, Brooklyn, NY, USA.
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Kim M, Zheng Z. Walking the VLDL tightrope in cardiometabolic diseases. Trends Endocrinol Metab 2024:S1043-2760(24)00201-7. [PMID: 39191606 DOI: 10.1016/j.tem.2024.07.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 07/22/2024] [Accepted: 07/26/2024] [Indexed: 08/29/2024]
Abstract
Very-low-density lipoprotein (VLDL), a triglyceride-rich lipoprotein secreted by hepatocytes, is pivotal for supplying peripheral tissues with fatty acids for energy production. As if walking on a tightrope, perturbations in the balance of VLDL metabolism contribute to cardiometabolic dysfunction, promoting pathologies such as cardiovascular disease (CVD) or metabolic dysfunction-associated steatotic liver disease (MASLD). Despite the advent of lipid-lowering therapies, including statins and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, risks for cardiovascular events persist. With limitations to currently available CVD therapeutics and no US Food and Drug Administration (FDA)-approved treatment for MASLD, this review summarizes the current understanding of VLDL metabolism that sheds light on novel therapeutic avenues to pursue for cardiometabolic disorders.
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Affiliation(s)
- Mindy Kim
- Medical Scientist Training Program, Medical College of Wisconsin, Milwaukee, 53226, USA; Department of Physiology, Medical College of Wisconsin, Milwaukee, 53226, USA.
| | - Ze Zheng
- Department of Physiology, Medical College of Wisconsin, Milwaukee, 53226, USA; Department of Medicine, Medical College of Wisconsin, Milwaukee, 53226, USA; Cardiovascular Center, Medical College of Wisconsin, Milwaukee, 53226, USA; Thrombosis & Hemostasis Program, Versiti Blood Research Institute, Milwaukee, 53226, USA.
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3
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Zhu B, Wu H, Li KS, Eisa-Beygi S, Singh B, Bielenberg DR, Huang W, Chen H. Two sides of the same coin: Non-alcoholic fatty liver disease and atherosclerosis. Vascul Pharmacol 2024; 154:107249. [PMID: 38070759 DOI: 10.1016/j.vph.2023.107249] [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: 11/03/2023] [Revised: 11/20/2023] [Accepted: 11/25/2023] [Indexed: 02/03/2024]
Abstract
The prevalence of non-alcoholic fatty liver disease (NAFLD) and atherosclerosis remain high, which is primarily due to widespread adoption of a western diet and sedentary lifestyle. NAFLD, together with advanced forms of this disease such as non-alcoholic steatohepatitis (NASH) and cirrhosis, are closely associated with atherosclerotic-cardiovascular disease (ASCVD). In this review, we discussed the association between NAFLD and atherosclerosis and expounded on the common molecular biomarkers underpinning the pathogenesis of both NAFLD and atherosclerosis. Furthermore, we have summarized the mode of function and potential clinical utility of existing drugs in the context of these diseases.
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Affiliation(s)
- Bo Zhu
- Vascular Biology Program, Boston Children's Hospital, Department of Surgery, Harvard Medical School, Boston, MA, United States of America
| | - Hao Wu
- Vascular Biology Program, Boston Children's Hospital, Department of Surgery, Harvard Medical School, Boston, MA, United States of America
| | - Kathryn S Li
- Vascular Biology Program, Boston Children's Hospital, Department of Surgery, Harvard Medical School, Boston, MA, United States of America
| | - Shahram Eisa-Beygi
- Vascular Biology Program, Boston Children's Hospital, Department of Surgery, Harvard Medical School, Boston, MA, United States of America
| | - Bandana Singh
- Vascular Biology Program, Boston Children's Hospital, Department of Surgery, Harvard Medical School, Boston, MA, United States of America
| | - Diane R Bielenberg
- Vascular Biology Program, Boston Children's Hospital, Department of Surgery, Harvard Medical School, Boston, MA, United States of America
| | - Wendong Huang
- Department of Diabetes Complications and Metabolism, Arthur Riggs Diabetes and Metabolic Research Institute, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA 91010, United States of America
| | - Hong Chen
- Vascular Biology Program, Boston Children's Hospital, Department of Surgery, Harvard Medical School, Boston, MA, United States of America.
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4
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van Zwol W, van de Sluis B, Ginsberg HN, Kuivenhoven JA. VLDL Biogenesis and Secretion: It Takes a Village. Circ Res 2024; 134:226-244. [PMID: 38236950 PMCID: PMC11284300 DOI: 10.1161/circresaha.123.323284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 09/21/2023] [Indexed: 01/23/2024]
Abstract
The production and secretion of VLDLs (very-low-density lipoproteins) by hepatocytes has a direct impact on liver fat content, as well as the concentrations of cholesterol and triglycerides in the circulation and thus affects both liver and cardiovascular health, respectively. Importantly, insulin resistance, excess caloric intake, and lack of physical activity are associated with overproduction of VLDL, hepatic steatosis, and increased plasma levels of atherogenic lipoproteins. Cholesterol and triglycerides in remnant particles generated by VLDL lipolysis are risk factors for atherosclerotic cardiovascular disease and have garnered increasing attention over the last few decades. Presently, however, increased risk of atherosclerosis is not the only concern when considering today's cardiometabolic patients, as they often also experience hepatic steatosis, a prevalent disorder that can progress to steatohepatitis and cirrhosis. This duality of metabolic risk highlights the importance of understanding the molecular regulation of the biogenesis of VLDL, the lipoprotein that transports triglycerides and cholesterol out of the liver. Fortunately, there has been a resurgence of interest in the intracellular assembly, trafficking, degradation, and secretion of VLDL by hepatocytes, which has led to many exciting new molecular insights that are the topic of this review. Increasing our understanding of the biology of this pathway will aid to the identification of novel therapeutic targets to improve both the cardiovascular and the hepatic health of cardiometabolic patients. This review focuses, for the first time, on this duality.
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Affiliation(s)
- Willemien van Zwol
- Department of Paediatrics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Bart van de Sluis
- Department of Paediatrics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Henry. N. Ginsberg
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Jan Albert Kuivenhoven
- Department of Paediatrics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
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5
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Sachan V, Le Dévéhat M, Roubtsova A, Essalmani R, Laurendeau JF, Garçon D, Susan-Resiga D, Duval S, Mikaeeli S, Hamelin J, Evagelidis A, Chong M, Paré G, Chernetsova E, Gao ZH, Robillard I, Ruiz M, Trinh VQH, Estall JL, Faraj M, Austin RC, Sauvageau M, Prat A, Kiss RS, Seidah NG. PCSK7: A novel regulator of apolipoprotein B and a potential target against non-alcoholic fatty liver disease. Metabolism 2024; 150:155736. [PMID: 37967646 DOI: 10.1016/j.metabol.2023.155736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 10/17/2023] [Accepted: 11/08/2023] [Indexed: 11/17/2023]
Abstract
BACKGROUND Epidemiological evidence links the proprotein convertase subtilisin/kexin 7 (PCSK7) to triglyceride (TG) metabolism. We associated the known PCSK7 gain-of-function non-coding SNP rs236918 with higher levels of plasma apolipoprotein B (apoB) and the loss-of-function coding variant p.Pro777Leu (SNP rs201598301) with lower apoB and TG. Herein, we aimed to unravel the in vivo role of liver PCSK7. METHODS We biochemically defined the functional role of PCSK7 in lipid metabolism using hepatic cell lines and Pcsk7-/- mice. Our findings were validated following subcutaneous administration of hepatocyte-targeted N-acetylgalactosamine (GalNAc)-antisense oligonucleotides (ASOs) against Pcsk7. RESULTS Independent of its proteolytic activity, membrane-bound PCSK7 binds apoB100 in the endoplasmic reticulum and enhances its secretion. Mechanistically, the loss of PCSK7/Pcsk7 leads to apoB100 degradation, triggering an unfolded protein response, autophagy, and β-oxidation, eventually reducing lipid accumulation in hepatocytes. Non-alcoholic fatty liver disease (NAFLD) was induced by a 12-week high fat/fructose/cholesterol diet in wild type (WT) and Pcsk7-/- mice that were then allowed to recover on a 4-week control diet. Pcsk7-/- mice recovered more effectively than WT mice from all NAFLD-related liver phenotypes. Finally, subcutaneous administration of GalNAc-ASOs targeting hepatic Pcsk7 to WT mice validated the above results. CONCLUSIONS Our data reveal hepatic PCSK7 as one of the major regulators of apoB, and its absence reduces apoB secretion from hepatocytes favoring its ubiquitination and degradation by the proteasome. This results in a cascade of events, eventually reducing hepatic lipid accumulation, thus supporting the notion of silencing PCSK7 mRNA in hepatocytes for targeting NAFLD.
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Affiliation(s)
- Vatsal Sachan
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Maïlys Le Dévéhat
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Anna Roubtsova
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Rachid Essalmani
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Jean-Francois Laurendeau
- RNA and Noncoding Mechanisms of Disease, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Damien Garçon
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Delia Susan-Resiga
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Stéphanie Duval
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Sahar Mikaeeli
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Josée Hamelin
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Alexandra Evagelidis
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Michael Chong
- Department of Biochemistry & Biomedical Sciences, McMaster University Faculty of Health Sciences, Hamilton, Ontario, Canada
| | - Guillaume Paré
- Department of Biochemistry & Biomedical Sciences, McMaster University Faculty of Health Sciences, Hamilton, Ontario, Canada
| | | | - Zu-Hua Gao
- Department of Pathology, McGill University Health Centre, Montréal, QC, Canada
| | - Isabelle Robillard
- Montreal Heart Institute, Metabolomics Platform, Montreal, Quebec, Canada; Department of Nutrition, Université de Montréal, Montréal, QC, Canada
| | - Matthieu Ruiz
- Montreal Heart Institute, Metabolomics Platform, Montreal, Quebec, Canada; Department of Nutrition, Université de Montréal, Montréal, QC, Canada
| | - Vincent Quoc-Huy Trinh
- Departement of Pathology and Cellular Biology, Institut de Recherche en Immunologie et Cancérologie, Université de Montréal, Montréal, QC, Canada
| | - Jennifer L Estall
- Molecular Mechanisms of Diabetes, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - May Faraj
- Nutrition Department, Université de Montréal, Research Unit on Nutrition, Lipoproteins and Cardiometabolic Diseases, Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC, Canada
| | - Richard C Austin
- Department of Medicine, Division of Nephrology, McMaster University, The Research Institute of St. Joe's Hamilton and the Hamilton Center for Kidney Research, Hamilton, ON, Canada
| | - Martin Sauvageau
- RNA and Noncoding Mechanisms of Disease, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Annik Prat
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada
| | - Robert S Kiss
- McGill University Health Centre Research Institute, Montréal, QC, Canada
| | - Nabil G Seidah
- Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montréal (IRCM), affiliated to the Université de Montréal, Montréal, QC, Canada.
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6
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van Zwol W, Rimbert A, Wolters JC, Smit M, Bloks VW, Kloosterhuis NJ, Huijkman NCA, Koster MH, Tharehalli U, de Neck SM, Bournez C, Fuh MM, Kuipers J, Rajan S, de Bruin A, Ginsberg HN, van Westen GJP, Hussain MM, Scheja L, Heeren J, Zimmerman P, van de Sluis B, Kuivenhoven JA. Loss of hepatic SMLR1 causes hepatosteatosis and protects against atherosclerosis due to decreased hepatic VLDL secretion. Hepatology 2023; 78:1418-1432. [PMID: 36053190 PMCID: PMC10581432 DOI: 10.1002/hep.32709] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 08/02/2022] [Accepted: 08/03/2022] [Indexed: 12/08/2022]
Abstract
BACKGROUND AND AIMS The assembly and secretion of VLDL from the liver, a pathway that affects hepatic and plasma lipids, remains incompletely understood. We set out to identify players in the VLDL biogenesis pathway by identifying genes that are co-expressed with the MTTP gene that encodes for microsomal triglyceride transfer protein, key to the lipidation of apolipoprotein B, the core protein of VLDL. Using human and murine transcriptomic data sets, we identified small leucine-rich protein 1 ( SMLR1 ), encoding for small leucine-rich protein 1, a protein of unknown function that is exclusively expressed in liver and small intestine. APPROACH AND RESULTS To assess the role of SMLR1 in the liver, we used somatic CRISPR/CRISPR-associated protein 9 gene editing to silence murine Smlr1 in hepatocytes ( Smlr1 -LKO). When fed a chow diet, male and female mice show hepatic steatosis, reduced plasma apolipoprotein B and triglycerides, and reduced VLDL secretion without affecting microsomal triglyceride transfer protein activity. Immunofluorescence studies show that SMLR1 is in the endoplasmic reticulum and Cis-Golgi complex. The loss of hepatic SMLR1 in female mice protects against diet-induced hyperlipidemia and atherosclerosis but causes NASH. On a high-fat, high-cholesterol diet, insulin and glucose tolerance tests did not reveal differences in male Smlr1 -LKO mice versus controls. CONCLUSIONS We propose a role for SMLR1 in the trafficking of VLDL from the endoplasmic reticulum to the Cis-Golgi complex. While this study uncovers SMLR1 as a player in the VLDL assembly, trafficking, and secretion pathway, it also shows that NASH can occur with undisturbed glucose homeostasis and atheroprotection.
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Affiliation(s)
- Willemien van Zwol
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Antoine Rimbert
- Université de Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France
| | - Justina C. Wolters
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Marieke Smit
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Vincent W. Bloks
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Niels J. Kloosterhuis
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Nicolette C. A. Huijkman
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Mirjam H. Koster
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Umesh Tharehalli
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Simon M. de Neck
- Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Colin Bournez
- Division of Drug Discovery and Safety, Leiden Academic Center for Drug Research, Leiden University, Leiden, The Netherlands
| | - Marceline M. Fuh
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg−Eppendorf, Hamburg, Germany
| | - Jeroen Kuipers
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Sujith Rajan
- Department of Foundations of Medicine, NYU Long Island School of Medicine, Mineola, New York, USA
| | - Alain de Bruin
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
- Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Henry N. Ginsberg
- Department of Medicine, Columbia University, Vagelos College of Physicians and Surgeons, New York, New York, USA
| | - Gerard J. P. van Westen
- Division of Drug Discovery and Safety, Leiden Academic Center for Drug Research, Leiden University, Leiden, The Netherlands
| | - M. Mahmood Hussain
- Department of Foundations of Medicine, NYU Long Island School of Medicine, Mineola, New York, USA
| | - Ludger Scheja
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg−Eppendorf, Hamburg, Germany
| | - Joerg Heeren
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg−Eppendorf, Hamburg, Germany
| | | | - Bart van de Sluis
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Jan Albert Kuivenhoven
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
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Hernandez-Ono A, Zhao YP, Murray JW, Östlund C, Lee MJ, Shi A, Dauer WT, Worman HJ, Ginsberg HN, Shin JY. Functional interaction of torsinA and its activators in liver lipid metabolism. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.21.545957. [PMID: 37547008 PMCID: PMC10401926 DOI: 10.1101/2023.06.21.545957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
TorsinA is an atypical ATPase that lacks intrinsic activity unless it is bound to its activators lamina-associated polypeptide 1 (LAP1) in the perinuclear space or luminal domain-like LAP1 (LULL1) throughout the endoplasmic reticulum. However, the interaction of torsinA with LAP1 and LULL1 has not yet been shown to modulate a defined physiological process in mammals in vivo . We previously demonstrated that depletion of torsinA from mouse hepatocytes leads to reduced liver triglyceride secretion and marked steatosis, whereas depletion of LAP1 had more modest similar effects. We now show that depletion of LULL1 alone does not significantly decrease liver triglyceride secretion or cause steatosis. However, simultaneous depletion of both LAP1 and LULL1 from hepatocytes leads to defective triglyceride secretion and marked steatosis similar to that observed with depletion of torsinA. Our results demonstrate that torsinA and its activators dynamically regulate a physiological process in mammals in vivo .
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Shi X, Feng D, Li D, Han P, Yang L, Wei W. A pan-cancer analysis of the oncogenic and immunological roles of apolipoprotein F (APOF) in human cancer. Eur J Med Res 2023; 28:190. [PMID: 37312170 DOI: 10.1186/s40001-023-01156-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 06/03/2023] [Indexed: 06/15/2023] Open
Abstract
BACKGROUND Apolipoprotein F (APOF) has been less studied in cancers. Thus, we aimed to perform a pan-cancer analysis of the oncogenic and immunological effects of APOF on human cancer. METHODS A standardized TCGA pan-cancer dataset was downloaded. Differential expression, clinical prognosis, genetic mutations, immune infiltration, epigenetic modifications, tumor stemness and heterogeneity were analyzed. We conducted all analyses through software R (version 3.6.3) and its suitable packages. RESULTS Overall, we found that the common cancers differentially expressed between tumor and normal samples and prognostic-associated were BRCA, PRAD, KIRP, and LIHC in terms of overall survival (OS), disease-free survival (DFS) and progression-free survival (PFS). The pan-cancer Spearman analysis showed that the mRNA expression of APOF was negatively correlated with four tumor stemness indexes (DMPss, DNAss, ENHss, and EREG-METHss) with statistical significance for PRAD and was positively correlated for LIHC. In terms of BRCA and PRAD patients, we found negative correlation of APOF with TMB, MSI, neo, HRD and LOH. The mutation frequencies of BRCA and LIHC were 0.3%. APOF expression was negatively correlated with immune infiltration and positively correlated with tumor purity for PRAD patients. The mRNA expression of APOF was negatively associated with most TILs for LIHC, B cells, CD4+ T cells, neutrophils, macrophages and dendritic cells, but was positively associated with CD8+ T cells. CONCLUSIONS Our pan-cancer study offered a relatively comprehensive understanding of the roles of APOF on BRCA, PRAD, KIRP, and LIHC.
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Affiliation(s)
- Xu Shi
- Department of Urology, Institute of Urology, West China Hospital, Sichuan University, Guoxue Xiang #37, Chengdu, 610041, China
| | - Dechao Feng
- Department of Urology, Institute of Urology, West China Hospital, Sichuan University, Guoxue Xiang #37, Chengdu, 610041, China
| | - Dengxiong Li
- Department of Urology, Institute of Urology, West China Hospital, Sichuan University, Guoxue Xiang #37, Chengdu, 610041, China
| | - Ping Han
- Department of Urology, Institute of Urology, West China Hospital, Sichuan University, Guoxue Xiang #37, Chengdu, 610041, China
| | - Lu Yang
- Department of Urology, Institute of Urology, West China Hospital, Sichuan University, Guoxue Xiang #37, Chengdu, 610041, China
| | - Wuran Wei
- Department of Urology, Institute of Urology, West China Hospital, Sichuan University, Guoxue Xiang #37, Chengdu, 610041, China.
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9
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Shen Y, Gu HM, Qin S, Zhang DW. Surf4, cargo trafficking, lipid metabolism, and therapeutic implications. J Mol Cell Biol 2023; 14:6852946. [PMID: 36574593 PMCID: PMC9929512 DOI: 10.1093/jmcb/mjac063] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/30/2022] [Accepted: 09/06/2022] [Indexed: 12/03/2022] Open
Abstract
Surfeit 4 is a polytopic transmembrane protein that primarily resides in the endoplasmic reticulum (ER) membrane. It is ubiquitously expressed and functions as a cargo receptor, mediating cargo transport from the ER to the Golgi apparatus via the canonical coat protein complex II (COPII)-coated vesicles or specific vesicles. It also participates in ER-Golgi protein trafficking through a tubular network. Meanwhile, it facilitates retrograde transportation of cargos from the Golgi apparatus to the ER through COPI-coated vesicles. Surf4 can selectively mediate export of diverse cargos, such as PCSK9 very low-density lipoprotein (VLDL), progranulin, α1-antitrypsin, STING, proinsulin, and erythropoietin. It has been implicated in facilitating VLDL secretion, promoting cell proliferation and migration, and increasing replication of positive-strand RNA viruses. Therefore, Surf4 plays a crucial role in various physiological and pathophysiological processes and emerges as a promising therapeutic target. However, the molecular mechanisms by which Surf4 selectively sorts diverse cargos for ER-Golgi protein trafficking remain elusive. Here, we summarize the most recent advances in Surf4, focusing on its role in lipid metabolism.
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Affiliation(s)
- Yishi Shen
- Group on the Molecular and Cell Biology of Lipids and Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6R 2G3, Canada
| | - Hong-Mei Gu
- Group on the Molecular and Cell Biology of Lipids and Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6R 2G3, Canada
| | - Shucun Qin
- Institute of Atherosclerosis in Shandong First Medical University (Shandong Academy of Medical Sciences), Taian 271016, China
| | - Da-Wei Zhang
- Group on the Molecular and Cell Biology of Lipids and Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6R 2G3, Canada
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10
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Lu K, Fan Q, Zou X. Antisense oligonucleotide is a promising intervention for liver diseases. Front Pharmacol 2022; 13:1061842. [PMID: 36569303 PMCID: PMC9780395 DOI: 10.3389/fphar.2022.1061842] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 11/28/2022] [Indexed: 12/13/2022] Open
Abstract
As the body's critical metabolic organ, the liver plays an essential role in maintaining proper body homeostasis. However, as people's living standards have improved and the number of unhealthy lifestyles has increased, the liver has become overburdened. These have made liver disease one of the leading causes of death worldwide. Under the influence of adverse factors, liver disease progresses from simple steatosis to hepatitis, to liver fibrosis, and finally to cirrhosis and cancer, followed by increased mortality. Until now, there has been a lack of accepted effective treatments for liver disease. Based on current research, antisense oligonucleotide (ASO), as an alternative intervention for liver diseases, is expected to be an effective treatment due to its high efficiency, low toxicity, low dosage, strong specificity, and additional positive characteristics. In this review, we will first introduce the design, modification, delivery, and the mechanisms of ASO, and then summarize the application of ASO in liver disease treatment, including in non-alcoholic fatty liver disease (NAFLD), hepatitis, liver fibrosis, and liver cancer. Finally, we discuss challenges and perspectives on the transfer of ASO drugs into clinical use. This review provides a current and comprehensive understanding of the integrative and systematic functions of ASO for its use in liver disease.
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Affiliation(s)
- Kailing Lu
- College of Chinese Materia Medica and Yunnan Key Laboratory of Southern Medicinal Utilization, Yunnan University of Chinese Medicine, Kunming, Yunnan, China
| | - Qijing Fan
- Center for Life Sciences, School of Life Sciences, Yunnan University, Kunming, Yunnan, China
| | - Xiaoju Zou
- College of Chinese Materia Medica and Yunnan Key Laboratory of Southern Medicinal Utilization, Yunnan University of Chinese Medicine, Kunming, Yunnan, China,*Correspondence: Xiaoju Zou,
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11
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Östlund C, Hernandez-Ono A, Turk SJ, Dauer WT, Ginsberg HN, Worman HJ, Shin JY. Hepatocytes Deficient in Nuclear Envelope Protein Lamina-associated Polypeptide 1 are an Ideal Mammalian System to Study Intranuclear Lipid Droplets. J Lipid Res 2022; 63:100277. [PMID: 36100089 PMCID: PMC9587410 DOI: 10.1016/j.jlr.2022.100277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 09/06/2022] [Accepted: 09/07/2022] [Indexed: 01/21/2023] Open
Abstract
Lipid droplets (LDs) are generally considered to be synthesized in the ER and utilized in the cytoplasm. However, LDs have been observed inside nuclei in some cells, although recent research on nuclear LDs has focused on cultured cell lines. To better understand nuclear LDs that occur in vivo, here we examined LDs in primary hepatocytes from mice following depletion of the nuclear envelope protein lamina-associated polypeptide 1 (LAP1). Microscopic image analysis showed that LAP1-depleted hepatocytes contain frequent nuclear LDs, which differ from cytoplasmic LDs in their associated proteins. We found type 1 nucleoplasmic reticula, which are invaginations of the inner nuclear membrane, are often associated with nuclear LDs in these hepatocytes. Furthermore, in vivo depletion of the nuclear envelope proteins lamin A and C from mouse hepatocytes led to severely abnormal nuclear morphology, but significantly fewer nuclear LDs than were observed upon depletion of LAP1. In addition, we show both high-fat diet feeding and fasting of mice increased cytoplasmic lipids in LAP1-depleted hepatocytes but reduced nuclear LDs, demonstrating a relationship of LD formation with nutritional state. Finally, depletion of microsomal triglyceride transfer protein did not change the frequency of nuclear LDs in LAP1-depleted hepatocytes, suggesting that it is not required for the biogenesis of nuclear LDs in these cells. Together, these data show that LAP1-depleted hepatocytes represent an ideal mammalian system to investigate the biogenesis of nuclear LDs and their partitioning between the nucleus and cytoplasm in response to changes in nutritional state and cellular metabolism in vivo.
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Affiliation(s)
- Cecilia Östlund
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA,Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Antonio Hernandez-Ono
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Samantha J. Turk
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA,Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - William T. Dauer
- Peter O’Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA,Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA,Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Henry N. Ginsberg
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Howard J. Worman
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA,Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Ji-Yeon Shin
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA,For correspondence: Ji-Yeon Shin
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12
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Shen Y, Gu HM, Zhai L, Wang B, Qin S, Zhang DW. The role of hepatic Surf4 in lipoprotein metabolism and the development of atherosclerosis in apoE -/- mice. Biochim Biophys Acta Mol Cell Biol Lipids 2022; 1867:159196. [PMID: 35803528 DOI: 10.1016/j.bbalip.2022.159196] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/25/2022] [Accepted: 06/30/2022] [Indexed: 11/26/2022]
Abstract
Elevated plasma levels of low-density lipoprotein-C (LDL-C) increase the risk of atherosclerotic cardiovascular disease. Circulating LDL is derived from very low-density lipoprotein (VLDL) metabolism and cleared by LDL receptor (LDLR). We have previously demonstrated that cargo receptor Surfeit 4 (Surf4) mediates VLDL secretion. Inhibition of hepatic Surf4 impairs VLDL secretion, significantly reduces plasma LDL-C levels, and markedly mitigates the development of atherosclerosis in LDLR knockout (Ldlr-/-) mice. Here, we investigated the role of Surf4 in lipoprotein metabolism and the development of atherosclerosis in another commonly used mouse model of atherosclerosis, apolipoprotein E knockout (apoE-/-) mice. Adeno-associated viral shRNA was used to silence Surf4 expression mainly in the liver of apoE-/- mice. In apoE-/- mice fed a regular chow diet, knockdown of Surf4 expression significantly reduced triglyceride secretion and plasma levels of non-HDL cholesterol and triglycerides without causing hepatic lipid accumulation or liver damage. When Surf4 was knocked down in apoE-/- mice fed the Western-type diet, we observed a significant reduction in plasma levels of non-HDL cholesterol, but not triglycerides. Knockdown of Surf4 did not increase hepatic cholesterol and triglyceride levels or cause liver damage, but significantly diminished atherosclerosis lesions. Therefore, our findings indicate the potential of hepatic Surf4 inhibition as a novel therapeutic strategy to reduce the risk of atherosclerotic cardiovascular disease.
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Affiliation(s)
- Yishi Shen
- Group on the Molecular and Cell Biology of Lipids and Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Hong-Mei Gu
- Group on the Molecular and Cell Biology of Lipids and Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Lei Zhai
- Institute of Atherosclerosis in Shandong First Medical University (Shandong Academy of Medical Sciences), Taian, China
| | - Binxiang Wang
- Institute of Atherosclerosis in Shandong First Medical University (Shandong Academy of Medical Sciences), Taian, China
| | - Shucun Qin
- Institute of Atherosclerosis in Shandong First Medical University (Shandong Academy of Medical Sciences), Taian, China.
| | - Da-Wei Zhang
- Group on the Molecular and Cell Biology of Lipids and Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
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13
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Yang L, Yu S, Yang Y, Wu H, Zhang X, Lei Y, Lei Z. Berberine improves liver injury induced glucose and lipid metabolic disorders via alleviating ER stress of hepatocytes and modulating gut microbiota in mice. Bioorg Med Chem 2022; 55:116598. [PMID: 34979291 DOI: 10.1016/j.bmc.2021.116598] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 12/20/2021] [Accepted: 12/27/2021] [Indexed: 12/16/2022]
Abstract
Liver injury mediated by endoplasmic reticulum (ER) stress can cause many kinds of liver diseases including hepatic glucose and lipid metabolic disorders, and long term liver injury would lead to cirrhosis and hepatic cancer. Therefore, effective drugs for treating liver injury are urgent in need. Berberine is a multifunctional drug of traditional Chinese medicine, and it can improve various liver diseases. To study the effects of berberine on ER stress-induced liver injury, tunicamycin was administrated to C57BL/6 mice with or without berberine pre-treatment. H&E staining was used to check the morphology and histology of liver tissues. The serum and liver tissues were harvested to test biochemical indexes and the expression levels of genes related with glucose and lipid metabolism, ER stress and unfold protein response (UPR). 16S rDNA sequence technology was conducted to check the fecal microbiota. Pre-administration with berberine could alleviate the excess accumulation of triglyceride (TG) in the liver of mice treated with tunicamycin. Tunicamycin administration caused significant increase of the expression level of genes related to ER stress and UPR, such as CHOP, Grp78 and ATF6, but the berberine pre-treatment could significantly downregulate the expression level of these genes. Tunicamycin administration resulted in increased ratio of Prevotellaceae to Erysipelotrichaceae at the family level of the fecal microbiota in mice, and this trend was reversed by the pre-treatment of berberine. These results demonstrated that berberine could improve liver injury induced hepatic metabolic disorders through relieving ER stress in hepatocytes and regulating gut microbiota in mice.
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Affiliation(s)
- Lanxiang Yang
- Guangdong Metabolic Diseases Research Center of Integrated Chinese and Western Medicine; Key Laboratory of Glucolipid Metabolic Disorder, Ministry of Education of China; Institute of Chinese Medicine, Guangdong Pharmaceutical University; Guangdong TCM Key Laboratory for Metabolic Diseases, Guangzhou 510006, P.R. China; School of Biological Engineering, Wuhu Institute of Technology, Wenjin West Road 201#, Wuhu 241003, P.R. China; School of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou Higher Education Mega Center, Guangzhou 510006, P.R. China
| | - Siping Yu
- Guangdong Metabolic Diseases Research Center of Integrated Chinese and Western Medicine; Key Laboratory of Glucolipid Metabolic Disorder, Ministry of Education of China; Institute of Chinese Medicine, Guangdong Pharmaceutical University; Guangdong TCM Key Laboratory for Metabolic Diseases, Guangzhou 510006, P.R. China; School of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou Higher Education Mega Center, Guangzhou 510006, P.R. China
| | - Yanhong Yang
- The First Affiliated Hospital (School of Clinical Medicine), Guangdong Pharmaceutical University, Nong-Lin-Xia Road 19#, Yue-Xiu District, Guangzhou 510080, P.R. China
| | - Huijuan Wu
- Guangdong Metabolic Diseases Research Center of Integrated Chinese and Western Medicine; Key Laboratory of Glucolipid Metabolic Disorder, Ministry of Education of China; Institute of Chinese Medicine, Guangdong Pharmaceutical University; Guangdong TCM Key Laboratory for Metabolic Diseases, Guangzhou 510006, P.R. China; School of Biological Engineering, Wuhu Institute of Technology, Wenjin West Road 201#, Wuhu 241003, P.R. China
| | - Xueying Zhang
- Guangdong Metabolic Diseases Research Center of Integrated Chinese and Western Medicine; Key Laboratory of Glucolipid Metabolic Disorder, Ministry of Education of China; Institute of Chinese Medicine, Guangdong Pharmaceutical University; Guangdong TCM Key Laboratory for Metabolic Diseases, Guangzhou 510006, P.R. China; School of Biological Engineering, Wuhu Institute of Technology, Wenjin West Road 201#, Wuhu 241003, P.R. China
| | - Yuting Lei
- Guangdong Metabolic Diseases Research Center of Integrated Chinese and Western Medicine; Key Laboratory of Glucolipid Metabolic Disorder, Ministry of Education of China; Institute of Chinese Medicine, Guangdong Pharmaceutical University; Guangdong TCM Key Laboratory for Metabolic Diseases, Guangzhou 510006, P.R. China
| | - Zili Lei
- Guangdong Metabolic Diseases Research Center of Integrated Chinese and Western Medicine; Key Laboratory of Glucolipid Metabolic Disorder, Ministry of Education of China; Institute of Chinese Medicine, Guangdong Pharmaceutical University; Guangdong TCM Key Laboratory for Metabolic Diseases, Guangzhou 510006, P.R. China.
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14
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Li Y, Sha Y, Wang H, He L, Li L, Wen S, Sheng L, Hu W, Zhou H. Intracellular C3 prevents hepatic steatosis by promoting autophagy and very-low-density lipoprotein secretion. FASEB J 2021; 35:e22037. [PMID: 34762761 DOI: 10.1096/fj.202100856r] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 09/30/2021] [Accepted: 10/26/2021] [Indexed: 01/07/2023]
Abstract
Complement component C3, mainly synthesized by hepatocytes, acts as the convergence point of three different pathways in activating the complement cascade. Besides its well-established roles in the extracellular milieu, C3 performs various intracellular functions such as immunomodulation and pathogen recognition. Although C3 is present at extremely high concentrations in hepatocytes, little is known about its intrahepatic function. In this study, we found that C3 knockout (C3-/- ) mice displayed accelerated hepatic triglyceride (TG) accumulation compared with C57BL/6J wild type mice. Mechanistically, C3 deficiency impaired lipophagy in hepatocytes, owing to the disrupted interaction between C3 and autophagy-related 16 like 1, which is essential for autolysosome assembly. Furthermore, lipophagy deficiency affected the function of the endoplasmic reticulum in C3-/- mice, subsequently affecting the expression of protein disulfide isomerase and activity of microsomal TG transfer protein, and ultimately impairing the production of hepatic very-low-density lipoproteins (VLDLs). Rapamycin and thapsigargin treatment accelerated VLDL secretion and alleviated hepatic lipid accumulation in C3-/- mice. Our study demonstrates that C3 promotes lipophagy to facilitate VLDL secretion in hepatocytes, thus playing an essential role in balancing TG levels in the liver.
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Affiliation(s)
- Yinling Li
- Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Yeqin Sha
- Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Haitao Wang
- Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Lianping He
- Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Longjun Li
- Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Shuang Wen
- Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Liang Sheng
- Department of Pharmacology, School of Basic Medical Science, Nanjing Medical University, Nanjing, China
| | - Weiguo Hu
- Shanghai Cancer Center and Institute of Biomedical Science, Shanghai Medical College, Fudan University, Shanghai, China
| | - Hong Zhou
- Department of Immunology, Nanjing Medical University, Nanjing, China.,Department of Cell Biology, School of Life Science, Anhui Medical University, Hefei, China
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15
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Abbey D, Conlon D, Rainville C, Elwyn S, Quiroz-Figueroa K, Billheimer J, Schultz DC, Hand NJ, Cherry S, Rader DJ. Lipid droplet screen in human hepatocytes identifies TRRAP as a regulator of cellular triglyceride metabolism. Clin Transl Sci 2021; 14:1369-1379. [PMID: 34156146 PMCID: PMC8301584 DOI: 10.1111/cts.12988] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 12/08/2020] [Indexed: 12/30/2022] Open
Abstract
Hepatocytes store triglycerides (TGs) in the form of lipid droplets (LDs), which are increased in hepatosteatosis. The regulation of hepatic LDs is poorly understood and new therapies to reduce hepatosteatosis are needed. We performed a siRNA kinase and phosphatase screen in HuH‐7 cells using high‐content automated imaging of LDs. Changes in accumulated lipids were quantified with developed pipeline that measures intensity, area, and number of LDs. Selected “hits,” which reduced lipid accumulation, were further validated with other lipid and expression assays. Among several siRNAs that resulted in significantly reduced LDs, one was targeted to the nuclear adapter protein, transformation/transcription domain‐associated protein (TRRAP). Knockdown of TRRAP reduced triglyceride accumulation in HuH‐7 hepatocytes, in part by reducing C/EBPα‐mediated de novo synthesis of TGs. These findings implicate TRRAP as a novel regulator of hepatic TG metabolism and nominate it as a potential drug target for hepatosteatosis.
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Affiliation(s)
- Deepti Abbey
- Department of Genetics, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Division of Translational Medicine and Human Genetics, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Donna Conlon
- Department of Genetics, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Division of Translational Medicine and Human Genetics, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Christopher Rainville
- High Throughput Screening Core, Department of Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Susannah Elwyn
- Department of Genetics, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Division of Translational Medicine and Human Genetics, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Katherine Quiroz-Figueroa
- Department of Genetics, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Division of Translational Medicine and Human Genetics, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jeffrey Billheimer
- Division of Translational Medicine and Human Genetics, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - David C Schultz
- High Throughput Screening Core, Department of Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Nicholas J Hand
- Department of Genetics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Sara Cherry
- Department of Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Daniel J Rader
- Department of Genetics, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Division of Translational Medicine and Human Genetics, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Cardiovascular Institute, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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16
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Wang B, Shen Y, Zhai L, Xia X, Gu HM, Wang M, Zhao Y, Chang X, Alabi A, Xing S, Deng S, Liu B, Wang G, Qin S, Zhang DW. Atherosclerosis-associated hepatic secretion of VLDL but not PCSK9 is dependent on cargo receptor protein Surf4. J Lipid Res 2021; 62:100091. [PMID: 34118252 PMCID: PMC8261665 DOI: 10.1016/j.jlr.2021.100091] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 05/11/2021] [Accepted: 06/01/2021] [Indexed: 02/05/2023] Open
Abstract
Plasma LDL is produced from catabolism of VLDL and cleared from circulation mainly via the hepatic LDL receptor (LDLR). Proprotein convertase subtilisin/kexin type 9 (PCSK9) promotes LDLR degradation, increasing plasma LDL-C levels. Circulating PCSK9 is mainly secreted by the liver, whereas VLDL is exclusively secreted by hepatocytes. However, the mechanism regulating their secretion is not completely understood. Surfeit 4 (Surf4) is a cargo receptor localized in the ER membrane. It recruits cargos into coat protein complex II vesicles to facilitate their secretion. Here, we investigated the role of Surf4 in VLDL and PCSK9 secretion. We generated Surf4 liver-specific knockout mice and found that knockout of Surf4 did not affect PCSK9 secretion, whereas it significantly reduced plasma levels of cholesterol, triglyceride, and lipid-binding protein apolipoprotein B (apoB). In cultured human hepatocytes, Surf4 coimmunoprecipitated and colocalized with apolipoprotein B100, and Surf4 silencing reduced secretion of apolipoprotein B100. Furthermore, knockdown of Surf4 in LDLR knockout (Ldlr−/−) mice significantly reduced triglyceride secretion, plasma levels of apoB and non-HDL-C, and the development of atherosclerosis. However, Surf4 liver-specific knockout mice and Surf4 knockdown in Ldlr−/− mice displayed similar levels of liver lipids and plasma alanine aminotransferase activity as control mice, indicating that inhibition of Surf4 does not cause notable liver damage. Expression of stearoyl-CoA desaturase-1 was also reduced in the liver of these mice, suggesting a reduction in de novo lipogenesis. In summary, hepatic deficiency of Surf4 reduced VLDL secretion and the development of atherosclerosis but did not cause significant hepatic lipid accumulation or liver damage.
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Affiliation(s)
- Bingxiang Wang
- Institute of Atherosclerosis and College of Basic Medical Sciences in Shandong First Medical University (Shandong Academy of Medical Sciences), Taian, China
| | - Yishi Shen
- Department of Pediatrics and Group on the Molecular and Cell Biology of Lipids, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Lei Zhai
- Institute of Atherosclerosis and College of Basic Medical Sciences in Shandong First Medical University (Shandong Academy of Medical Sciences), Taian, China
| | - Xiaodan Xia
- Department of Orthopedics, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, Qingyuan, China
| | - Hong-Mei Gu
- Department of Pediatrics and Group on the Molecular and Cell Biology of Lipids, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Maggie Wang
- Department of Pediatrics and Group on the Molecular and Cell Biology of Lipids, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Yongfang Zhao
- Institute of Atherosclerosis and College of Basic Medical Sciences in Shandong First Medical University (Shandong Academy of Medical Sciences), Taian, China
| | - Xiaole Chang
- Institute of Atherosclerosis and College of Basic Medical Sciences in Shandong First Medical University (Shandong Academy of Medical Sciences), Taian, China
| | - Adekunle Alabi
- Department of Pediatrics and Group on the Molecular and Cell Biology of Lipids, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Sijie Xing
- Department of Pediatrics and Group on the Molecular and Cell Biology of Lipids, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Shijun Deng
- Department of Pediatrics and Group on the Molecular and Cell Biology of Lipids, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Boyan Liu
- Institute of Atherosclerosis and College of Basic Medical Sciences in Shandong First Medical University (Shandong Academy of Medical Sciences), Taian, China
| | - Guiqing Wang
- Department of Orthopedics, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, Qingyuan, China
| | - Shucun Qin
- Institute of Atherosclerosis and College of Basic Medical Sciences in Shandong First Medical University (Shandong Academy of Medical Sciences), Taian, China.
| | - Da-Wei Zhang
- Department of Pediatrics and Group on the Molecular and Cell Biology of Lipids, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
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17
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Clodronate, an inhibitor of the vesicular nucleotide transporter, ameliorates steatohepatitis and acute liver injury. Sci Rep 2021; 11:5192. [PMID: 33664289 PMCID: PMC7933178 DOI: 10.1038/s41598-021-83144-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 01/27/2021] [Indexed: 12/12/2022] Open
Abstract
The vesicular nucleotide transporter (VNUT) is responsible for the vesicular storage and release of ATP from various ATP-secreting cells, and it plays an essential role in purinergic signaling. Although extracellular ATP and its degradation products are known to mediate various inflammatory responses via purinoceptors, whether vesicular ATP release affects steatohepatitis and acute liver injury is far less understood. In the present study, we investigated the effects of clodronate, a potent and selective VNUT inhibitor, on acute and chronic liver inflammation in mice. In a model of methionine/choline-deficient diet-induced non-alcoholic steatohepatitis (NASH), the administration of clodronate reduced hepatic inflammation, fibrosis, and triglyceride accumulation. Clodronate also protected mice against high-fat/high-cholesterol diet-induced steatohepatitis. Moreover, prophylactic administration of clodronate prevented d-galactosamine and lipopolysaccharide-induced acute liver injury by reducing inflammatory cytokines and hepatocellular apoptosis. In vitro, clodronate inhibited glucose-induced vesicular ATP release mediated by VNUT and reduced the intracellular level and secretion of triglycerides in isolated hepatocytes. These results suggest that VNUT-dependent vesicular ATP release plays a crucial role in the recruitment of immune cells, cytokine production, and the aggravation of steatosis in the liver. Pharmacological inhibition of VNUT may provide therapeutic benefits in liver inflammatory disorders, including NASH and acute toxin-induced injury.
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18
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Östlund C, Hernandez-Ono A, Shin JY. The Nuclear Envelope in Lipid Metabolism and Pathogenesis of NAFLD. BIOLOGY 2020; 9:biology9100338. [PMID: 33076344 PMCID: PMC7602593 DOI: 10.3390/biology9100338] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 02/06/2023]
Abstract
Simple Summary The liver is a major organ regulating lipid metabolism and a proper liver function is essential to health. Nonalcoholic fatty liver disease (NAFLD) is a condition with abnormal fat accumulation in the liver without heavy alcohol use. NAFLD is becoming one of the most common liver diseases with the increase in obesity in many parts of the world. There is no approved cure for the disease and a better understanding of disease mechanism is needed for effective prevention and treatment. The nuclear envelope, a membranous structure that surrounds the cell nucleus, is connected to the endoplasmic reticulum where the vast majority of cellular lipids are synthesized. Growing evidence indicates that components in the nuclear envelope are involved in cellular lipid metabolism. We review published studies with various cell and animal models, indicating the essential roles of nuclear envelope proteins in lipid metabolism. We also discuss how defects in these proteins affect cellular lipid metabolism and possibly contribute to the pathogenesis of NAFLD. Abstract Nonalcoholic fatty liver disease (NAFLD) is a burgeoning public health problem worldwide. Despite its tremendous significance for public health, we lack a comprehensive understanding of the pathogenic mechanisms of NAFLD and its more advanced stage, nonalcoholic steatohepatitis (NASH). Identification of novel pathways or cellular mechanisms that regulate liver lipid metabolism has profound implications for the understanding of the pathology of NAFLD and NASH. The nuclear envelope is topologically connected to the ER, where protein synthesis and lipid synthesis occurs. Emerging evidence points toward that the nuclear lamins and nuclear membrane-associated proteins are involved in lipid metabolism and homeostasis. We review published reports that link these nuclear envelope proteins to lipid metabolism. In particular, we focus on the recent work demonstrating the essential roles for the nuclear envelope-localized torsinA/lamina-associated polypeptide (LAP1) complex in hepatic steatosis, lipid secretion, and NASH development. We also discuss plausible pathogenic mechanisms by which the loss of either protein in hepatocytes leads to hepatic dyslipidemia and NASH development.
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Affiliation(s)
- Cecilia Östlund
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; (C.Ö.); (A.H.-O.)
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Antonio Hernandez-Ono
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; (C.Ö.); (A.H.-O.)
| | - Ji-Yeon Shin
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; (C.Ö.); (A.H.-O.)
- Correspondence: ; Tel.: +1-212-305-4088
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19
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Roger C, Buch C, Muller T, Leemput J, Demizieux L, Passilly-Degrace P, Cinar R, Iyer MR, Kunos G, Vergès B, Degrace P, Jourdan T. Simultaneous Inhibition of Peripheral CB1R and iNOS Mitigates Obesity-Related Dyslipidemia Through Distinct Mechanisms. Diabetes 2020; 69:2120-2132. [PMID: 32680936 PMCID: PMC7506827 DOI: 10.2337/db20-0078] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 07/05/2020] [Indexed: 12/17/2022]
Abstract
Diabetic dyslipidemia, characterized by increased plasma triglycerides and decreased HDL cholesterol levels, is a major factor contributing to nonalcoholic steatohepatitis and cardiovascular risk in type 2 diabetes. Activation of the cannabinoid-1 receptor (CB1R) and activation of inducible nitric oxide synthase (iNOS) are associated with nonalcoholic steatohepatitis progression. Here, we tested whether dual-targeting inhibition of hepatic CB1R and iNOS improves diabetic dyslipidemia in mice with diet-induced obesity (DIO mice). DIO mice were treated for 14 days with (S)-MRI-1867, a peripherally restricted hybrid inhibitor of CB1R and iNOS. (R)-MRI-1867, the CB1R-inactive stereoisomer that retains iNOS inhibitory activity, and JD-5037, a peripherally restricted CB1R antagonist, were used to assess the relative contribution of the two targets to the effects of (S)-MRI-1867. (S)-MRI-1867 reduced hepatic steatosis and the rate of hepatic VLDL secretion, upregulated hepatic LDLR expression, and reduced the circulating levels of proprotein convertase subtilisin/kexin type 9 (PCSK9). The decrease in VLDL secretion could be attributed to CB1R blockade, while the reduction of PCSK9 levels and the related increase in LDLR resulted from iNOS inhibition via an mTOR complex 1-dependent mechanism. In conclusion, this approach based on the concomitant inhibition of CB1R and iNOS represents a promising therapeutic strategy for the treatment of dyslipidemia.
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Affiliation(s)
- Célia Roger
- INSERM Lipids, Nutrition, Cancer (LNC) UMR1231, Team PADYS, University of Burgundy and Franche-Comté, Dijon, France
| | - Chloé Buch
- INSERM Lipids, Nutrition, Cancer (LNC) UMR1231, Team PADYS, University of Burgundy and Franche-Comté, Dijon, France
| | - Tania Muller
- INSERM Lipids, Nutrition, Cancer (LNC) UMR1231, Team PADYS, University of Burgundy and Franche-Comté, Dijon, France
| | - Julia Leemput
- INSERM Lipids, Nutrition, Cancer (LNC) UMR1231, Team PADYS, University of Burgundy and Franche-Comté, Dijon, France
| | - Laurent Demizieux
- INSERM Lipids, Nutrition, Cancer (LNC) UMR1231, Team PADYS, University of Burgundy and Franche-Comté, Dijon, France
| | - Patricia Passilly-Degrace
- INSERM Lipids, Nutrition, Cancer (LNC) UMR1231, Team PADYS, University of Burgundy and Franche-Comté, Dijon, France
| | - Resat Cinar
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD
| | - Malliga R Iyer
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD
| | - George Kunos
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD
| | - Bruno Vergès
- INSERM Lipids, Nutrition, Cancer (LNC) UMR1231, Team PADYS, University of Burgundy and Franche-Comté, Dijon, France
| | - Pascal Degrace
- INSERM Lipids, Nutrition, Cancer (LNC) UMR1231, Team PADYS, University of Burgundy and Franche-Comté, Dijon, France
| | - Tony Jourdan
- INSERM Lipids, Nutrition, Cancer (LNC) UMR1231, Team PADYS, University of Burgundy and Franche-Comté, Dijon, France
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20
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Multifarious roles of lipid droplets in autophagy - Target, product, and what else? Semin Cell Dev Biol 2020; 108:47-54. [PMID: 32169402 DOI: 10.1016/j.semcdb.2020.02.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/12/2020] [Accepted: 02/29/2020] [Indexed: 01/09/2023]
Abstract
Lipid droplets (LDs) are not an inert storage of excessive lipids, but play various roles in cellular lipid metabolism. Autophagy involves several mechanisms for the degradation of cellular components, and is related to many aspects of lipid metabolism. LD and autophagic membranes often distribute in proximity, but their relationship is complex. LDs can be degraded by autophagy, but LDs are also generated as a result of autophagy or support the execution of autophagy. Moreover, several proteins crucial for autophagy were shown to affect different aspects of LD formation. This article aims to categorize this multifaceted and seemingly entangled LD-autophagy relationship and to discuss unresolved issues.
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21
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Ren L, Yi J, Li W, Zheng X, Liu J, Wang J, Du G. Apolipoproteins and cancer. Cancer Med 2019; 8:7032-7043. [PMID: 31573738 PMCID: PMC6853823 DOI: 10.1002/cam4.2587] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 09/11/2019] [Accepted: 09/13/2019] [Indexed: 12/19/2022] Open
Abstract
The role of apolipoproteins in cardiovascular disease has been well investigated, but their participation in cancer has only been explored in a few published studies which showed a close link with certain kinds of cancer. In this review, we focused on the function of different kinds of apolipoproteins in cancers, autophagy, oxidative stress, and drug resistance. The potential application of apolipoproteins as biomarkers for cancer diagnosis and prognosis was highlighted, together with an investigation of their potential as drug targets for cancer treatment. Many important roles of apolipoproteins and their mechanisms in cancers were reviewed in detail and future perspectives of apolipoprotein research were discussed.
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Affiliation(s)
- Liwen Ren
- The State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Beijing, China.,Key Laboratory of Drug Target Research and Drug Screen, Institute of Materia Medica, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Jie Yi
- Department of Clinical Laboratory, Peking Union Medical College Hospital, Beijing, People's Republic of China
| | - Wan Li
- The State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Beijing, China.,Key Laboratory of Drug Target Research and Drug Screen, Institute of Materia Medica, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Xiangjin Zheng
- The State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Beijing, China.,Key Laboratory of Drug Target Research and Drug Screen, Institute of Materia Medica, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Jinyi Liu
- The State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Beijing, China.,Key Laboratory of Drug Target Research and Drug Screen, Institute of Materia Medica, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Jinhua Wang
- The State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Beijing, China.,Key Laboratory of Drug Target Research and Drug Screen, Institute of Materia Medica, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Guanhua Du
- The State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Beijing, China.,Key Laboratory of Drug Target Research and Drug Screen, Institute of Materia Medica, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
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22
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Challa TD, Wueest S, Lucchini FC, Dedual M, Modica S, Borsigova M, Wolfrum C, Blüher M, Konrad D. Liver ASK1 protects from non-alcoholic fatty liver disease and fibrosis. EMBO Mol Med 2019; 11:e10124. [PMID: 31595673 PMCID: PMC6783644 DOI: 10.15252/emmm.201810124] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Revised: 04/30/2019] [Accepted: 05/03/2019] [Indexed: 12/15/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is strongly associated with obesity and may progress to non-alcoholic steatohepatitis (NASH) and liver fibrosis. The deficit of pharmacological therapies for the latter mainly results from an incomplete understanding of involved pathological mechanisms. Herein, we identify apoptosis signal-regulating kinase 1 (ASK1) as a suppressor of NASH and fibrosis formation. High-fat diet-fed and aged chow-fed liver-specific ASK1-knockout mice develop a higher degree of hepatic steatosis, inflammation, and fibrosis compared to controls. In addition, pharmacological inhibition of ASK1 increased hepatic lipid accumulation in wild-type mice. In line, liver-specific ASK1 overexpression protected mice from the development of high-fat diet-induced hepatic steatosis and carbon tetrachloride-induced fibrosis. Mechanistically, ASK1 depletion blunts autophagy, thereby enhancing lipid droplet accumulation and liver fibrosis. In human livers of lean and obese subjects, ASK1 expression correlated negatively with liver fat content and NASH scores, but positively with markers for autophagy. Taken together, ASK1 may be a novel therapeutic target to tackle NAFLD and liver fibrosis.
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Affiliation(s)
- Tenagne D Challa
- Division of Pediatric Endocrinology and DiabetologyUniversity Children's HospitalZurichSwitzerland
- Children's Research CenterUniversity Children's HospitalZurichSwitzerland
| | - Stephan Wueest
- Division of Pediatric Endocrinology and DiabetologyUniversity Children's HospitalZurichSwitzerland
- Children's Research CenterUniversity Children's HospitalZurichSwitzerland
| | - Fabrizio C Lucchini
- Division of Pediatric Endocrinology and DiabetologyUniversity Children's HospitalZurichSwitzerland
- Children's Research CenterUniversity Children's HospitalZurichSwitzerland
- Zurich Center for Integrative Human PhysiologyUniversity of ZurichZurichSwitzerland
| | - Mara Dedual
- Division of Pediatric Endocrinology and DiabetologyUniversity Children's HospitalZurichSwitzerland
- Children's Research CenterUniversity Children's HospitalZurichSwitzerland
- Zurich Center for Integrative Human PhysiologyUniversity of ZurichZurichSwitzerland
| | - Salvatore Modica
- Institute of Food, Nutrition and HealthETH ZurichSchwerzenbachSwitzerland
| | - Marcela Borsigova
- Division of Pediatric Endocrinology and DiabetologyUniversity Children's HospitalZurichSwitzerland
- Children's Research CenterUniversity Children's HospitalZurichSwitzerland
| | - Christian Wolfrum
- Institute of Food, Nutrition and HealthETH ZurichSchwerzenbachSwitzerland
| | | | - Daniel Konrad
- Division of Pediatric Endocrinology and DiabetologyUniversity Children's HospitalZurichSwitzerland
- Children's Research CenterUniversity Children's HospitalZurichSwitzerland
- Zurich Center for Integrative Human PhysiologyUniversity of ZurichZurichSwitzerland
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23
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Li D, Rodia CN, Johnson ZK, Bae M, Muter A, Heussinger AE, Tambini N, Longo AM, Dong H, Lee JY, Kohan AB. Intestinal basolateral lipid substrate transport is linked to chylomicron secretion and is regulated by apoC-III. J Lipid Res 2019; 60:1503-1515. [PMID: 31152000 PMCID: PMC6718441 DOI: 10.1194/jlr.m092460] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 05/31/2019] [Indexed: 01/26/2023] Open
Abstract
Chylomicron metabolism is critical for determining plasma levels of triacylglycerols (TAGs) and cholesterol, both of which are risk factors for CVD. The rates of chylomicron secretion and remnant clearance are controlled by intracellular and extracellular factors, including apoC-III. We have previously shown that human apoC-III overexpression in mice (apoC-IIITg mice) decreases the rate of chylomicron secretion into lymph, as well as the TAG composition in chylomicrons. We now find that this decrease in chylomicron secretion is not due to the intracellular effects of apoC-III, but instead that primary murine enteroids are capable of taking up TAG from TAG-rich lipoproteins (TRLs) on their basolateral surface; and via Seahorse analyses, we find that mitochondrial respiration is induced by basolateral TRLs. Furthermore, TAG uptake into the enterocyte is inhibited when excess apoC-III is present on TRLs. In vivo, we find that dietary TAG is diverted from the cytosolic lipid droplets and driven toward mitochondrial FA oxidation when plasma apoC-III is high (or when basolateral substrates are absent). We propose that this pathway of basolateral lipid substrate transport (BLST) plays a physiologically relevant role in the maintenance of dietary lipid absorption and chylomicron secretion. Further, when apoC-III is in excess, it inhibits BLST and chylomicron secretion.
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Affiliation(s)
- Diana Li
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT
| | - Cayla N Rodia
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT
| | - Zania K Johnson
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT
| | - Minkyung Bae
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT
| | - Angelika Muter
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT
| | - Amy E Heussinger
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT
| | - Nicholas Tambini
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT
| | - Austin M Longo
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT
| | - Hongli Dong
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT
| | - Ji-Young Lee
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT
| | - Alison B Kohan
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT.
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24
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Shin JY, Hernandez-Ono A, Fedotova T, Östlund C, Lee MJ, Gibeley SB, Liang CC, Dauer WT, Ginsberg HN, Worman HJ. Nuclear envelope-localized torsinA-LAP1 complex regulates hepatic VLDL secretion and steatosis. J Clin Invest 2019; 129:4885-4900. [PMID: 31408437 PMCID: PMC6819140 DOI: 10.1172/jci129769] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 08/07/2019] [Indexed: 12/15/2022] Open
Abstract
Deciphering novel pathways regulating liver lipid content has profound implications for understanding the pathophysiology of nonalcoholic fatty liver disease and nonalcoholic steatohepatitis. Recent evidence suggests that the nuclear envelope is a site of regulation of lipid metabolism but there is limited appreciation of the responsible mechanisms and molecular components within this organelle. We showed that conditional hepatocyte deletion of the inner nuclear membrane protein lamina-associated polypeptide 1 (LAP1) caused defective VLDL secretion and steatosis, including intranuclear lipid accumulation. LAP1 binds to and activates torsinA, an AAA+ ATPase that resides in the perinuclear space and continuous main ER. Deletion of torsinA from mouse hepatocytes caused even greater reductions in VLDL secretion and profound steatosis. Both of these mutant mouse lines developed hepatic steatosis and subsequent steatohepatitis on a regular chow diet in the absence of whole-body insulin resistance or obesity. Our results establish an essential role for the nuclear envelope-localized torsinA-LAP1 complex in hepatic VLDL secretion and suggest that the torsinA pathway participates in the pathophysiology of nonalcoholic fatty liver disease.
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Affiliation(s)
- Ji-Yeon Shin
- Department of Medicine, and
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | | | | | - Cecilia Östlund
- Department of Medicine, and
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Michael J. Lee
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | | | | | - William T. Dauer
- Department of Neurology, and
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | | | - Howard J. Worman
- Department of Medicine, and
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
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25
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Coupling of COPII vesicle trafficking to nutrient availability by the IRE1α-XBP1s axis. Proc Natl Acad Sci U S A 2019; 116:11776-11785. [PMID: 31123148 DOI: 10.1073/pnas.1814480116] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The cytoplasmic coat protein complex-II (COPII) is evolutionarily conserved machinery that is essential for efficient trafficking of protein and lipid cargos. How the COPII machinery is regulated to meet the metabolic demand in response to alterations of the nutritional state remains largely unexplored, however. Here, we show that dynamic changes of COPII vesicle trafficking parallel the activation of transcription factor X-box binding protein 1 (XBP1s), a critical transcription factor in handling cellular endoplasmic reticulum (ER) stress in both live cells and mouse livers upon physiological fluctuations of nutrient availability. Using live-cell imaging approaches, we demonstrate that XBP1s is sufficient to promote COPII-dependent trafficking, mediating the nutrient stimulatory effects. Chromatin immunoprecipitation (ChIP) coupled with high-throughput DNA sequencing (ChIP-seq) and RNA-sequencing analyses reveal that nutritional signals induce dynamic XBP1s occupancy of promoters of COPII traffic-related genes, thereby driving the COPII-mediated trafficking process. Liver-specific disruption of the inositol-requiring enzyme 1α (IRE1α)-XBP1s signaling branch results in diminished COPII vesicle trafficking. Reactivation of XBP1s in mice lacking hepatic IRE1α restores COPII-mediated lipoprotein secretion and reverses the fatty liver and hypolipidemia phenotypes. Thus, our results demonstrate a previously unappreciated mechanism in the metabolic control of liver protein and lipid trafficking: The IRE1α-XBP1s axis functions as a nutrient-sensing regulatory nexus that integrates nutritional states and the COPII vesicle trafficking.
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26
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Sandesara PB, Virani SS, Fazio S, Shapiro MD. The Forgotten Lipids: Triglycerides, Remnant Cholesterol, and Atherosclerotic Cardiovascular Disease Risk. Endocr Rev 2019; 40:537-557. [PMID: 30312399 PMCID: PMC6416708 DOI: 10.1210/er.2018-00184] [Citation(s) in RCA: 269] [Impact Index Per Article: 53.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 10/08/2018] [Indexed: 12/11/2022]
Abstract
Atherosclerotic cardiovascular disease (ASCVD) remains the leading cause of death worldwide. Low-density lipoprotein cholesterol (LDL-C) is a well-established mediator of atherosclerosis and a key target for intervention for the primary and secondary prevention of ASCVD. However, despite substantial reduction in LDL-C, patients continue to have recurrent ASCVD events. Hypertriglyceridemia may be an important contributor of this residual risk. Observational and genetic epidemiological data strongly support a causal role of triglycerides (TGs) and the cholesterol content within triglyceride-rich lipoproteins (TGRLs) and/or remnant cholesterol (RC) in the development of ASCVD. TGRLs are composed of hepatically derived very low-density lipoprotein and intestinally derived chylomicrons. RC is the cholesterol content of all TGRLs and plasma TGs serve as a surrogate measure of TGRLs and RC. Although lifestyle modification remains the cornerstone for management of hypertriglyceridemia, many novel drugs are in development and have shown impressive efficacy in lowering TG levels. Several ongoing, randomized controlled trials are underway to examine the impact of these novel agents on ASCVD outcomes. In this comprehensive review, we provide an overview of the biology, epidemiology, and genetics of TGs and ASCVD; we discuss current and novel TG-lowering therapies under development.
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Affiliation(s)
- Pratik B Sandesara
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Salim S Virani
- Michael E. DeBakey Veterans Affairs Medical Center, Houston, Texas.,Baylor College of Medicine, Houston, Texas
| | - Sergio Fazio
- Center for Preventive Cardiology, Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon
| | - Michael D Shapiro
- Center for Preventive Cardiology, Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon
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27
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Kim S, Graham MJ, Lee RG, Yang L, Kim S, Subramanian V, Layne JD, Cai L, Temel RE, Shih D, Lusis AJ, Berliner JA, Lee S. Heparin-binding EGF-like growth factor (HB-EGF) antisense oligonucleotide protected against hyperlipidemia-associated atherosclerosis. Nutr Metab Cardiovasc Dis 2019; 29:306-315. [PMID: 30738642 PMCID: PMC6452438 DOI: 10.1016/j.numecd.2018.12.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 11/24/2018] [Accepted: 12/27/2018] [Indexed: 01/08/2023]
Abstract
BACKGROUND AND AIMS Heparin-binding EGF-like growth factor (HB-EGF) is a representative EGF family member that interacts with EGFR under diverse stress environment. Previously, we reported that the HB-EGF-targeting using antisense oligonucleotide (ASO) effectively suppressed an aortic aneurysm in the vessel wall and circulatory lipid levels. In this study, we further examined the effects of the HB-EGF ASO administration on the development of hyperlipidemia-associated atherosclerosis using an atherogenic mouse model. METHODS AND RESULTS The male and female LDLR deficient mice under Western diet containing 21% fat and 0.2% cholesterol content were cotreated with control and HB-EGF ASOs for 12 weeks. We observed that the HB-EGF ASO administration effectively downregulated circulatory VLDL- and LDL-associated lipid levels in circulation; concordantly, the HB-EGF targeting effectively suppressed the development of atherosclerosis in the aorta. An EGFR blocker BIBX1382 administration suppressed the hepatic TG secretion rate, suggesting a positive role of the HB-EGF signaling for the hepatic VLDL production. We newly observed that there was a significant improvement of the insulin sensitivity by the HB-EGF ASO administration in a mouse model under the Western diet as demonstrated by the improvement of the glucose and insulin tolerances. CONCLUSION The HB-EGF ASO administration effectively downregulated circulatory lipid levels by suppressing hepatic VLDL production rate, which leads to effective protection against atherosclerosis in the vascular wall.
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Affiliation(s)
- S Kim
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, 40536, USA
| | - M J Graham
- Cardiovascular Antisense Drug Discovery Group, Ionis Pharmaceuticals, Carlsbad, CA, 92010, USA
| | - R G Lee
- Cardiovascular Antisense Drug Discovery Group, Ionis Pharmaceuticals, Carlsbad, CA, 92010, USA
| | - L Yang
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, 40536, USA
| | - S Kim
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, 40536, USA
| | - V Subramanian
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, 40536, USA; Department of Physiology, University of Kentucky, Lexington, KY, 40536, USA
| | - J D Layne
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, 40536, USA
| | - L Cai
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, 40536, USA
| | - R E Temel
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, 40536, USA; Department of Physiology, University of Kentucky, Lexington, KY, 40536, USA
| | - D Shih
- Department of Medicine-Cardiology, University of California-Los Angeles (UCLA) School of Medicine, Los Angeles, CA, 90095, USA
| | - A J Lusis
- Department of Medicine-Cardiology, University of California-Los Angeles (UCLA) School of Medicine, Los Angeles, CA, 90095, USA; Department of Human Genetics, University of California-Los Angeles (UCLA) School of Medicine, Los Angeles, CA, 90095, USA; Department of Microbiology, Immunology & Molecular Genetics, University of California-Los Angeles (UCLA), Los Angeles, CA, 90095, USA
| | - J A Berliner
- Department of Pathology and Laboratory Medicine, University of California-Los Angeles (UCLA), Los Angeles, CA, 90095, USA
| | - S Lee
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, 40536, USA; Department of Pharmacology & Nutritional Sciences, University of Kentucky, Lexington, KY, 40536, USA.
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28
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Sołtysik K, Ohsaki Y, Tatematsu T, Cheng J, Fujimoto T. Nuclear lipid droplets derive from a lipoprotein precursor and regulate phosphatidylcholine synthesis. Nat Commun 2019; 10:473. [PMID: 30692541 PMCID: PMC6349838 DOI: 10.1038/s41467-019-08411-x] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 01/10/2019] [Indexed: 02/07/2023] Open
Abstract
The origin and physiological significance of lipid droplets (LDs) in the nucleus is not clear. Here we show that nuclear LDs in hepatocytes are derived from apolipoprotein B (ApoB)-free lumenal LDs, a precursor to very low-density lipoproprotein (VLDL) generated in the ER lumen by microsomal triglyceride transfer protein. ApoB-free lumenal LDs accumulate under ER stress, grow within the lumen of the type I nucleoplasmic reticulum, and turn into nucleoplasmic LDs by disintegration of the surrounding inner nuclear membrane. Oleic acid with or without tunicamycin significantly increases the formation of nucleoplasmic LDs, to which CTP:phosphocholine cytidylyltransferase α (CCTα) is recruited, resulting in activation of phosphatidylcholine (PC) synthesis. Perilipin-3 competes with CCTα in binding to nucleoplasmic LDs, and thus, knockdown and overexpression of perilipin-3 increases and decreases PC synthesis, respectively. The results indicate that nucleoplasmic LDs in hepatocytes constitute a feedback mechanism to regulate PC synthesis in accordance with ER stress. The origin and physiological significance of lipid droplets (LDs) in the nucleus is not clear. Here authors show that nucleoplasmic LDs in hepatocytes are derived from apolipoprotein B (ApoB)-free lumenal LDs and constitute a feedback mechanism to regulate PC synthesis in accordance with ER stress.
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Affiliation(s)
- Kamil Sołtysik
- Department of Molecular Cell Biology and Anatomy, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Yuki Ohsaki
- Department of Molecular Cell Biology and Anatomy, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan.
| | - Tsuyako Tatematsu
- Department of Molecular Cell Biology and Anatomy, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Jinglei Cheng
- Department of Molecular Cell Biology and Anatomy, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Toyoshi Fujimoto
- Department of Molecular Cell Biology and Anatomy, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan.
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29
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Ke PY. Diverse Functions of Autophagy in Liver Physiology and Liver Diseases. Int J Mol Sci 2019; 20:E300. [PMID: 30642133 PMCID: PMC6358975 DOI: 10.3390/ijms20020300] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 01/05/2019] [Accepted: 01/08/2019] [Indexed: 01/09/2023] Open
Abstract
Autophagy is a catabolic process by which eukaryotic cells eliminate cytosolic materials through vacuole-mediated sequestration and subsequent delivery to lysosomes for degradation, thus maintaining cellular homeostasis and the integrity of organelles. Autophagy has emerged as playing a critical role in the regulation of liver physiology and the balancing of liver metabolism. Conversely, numerous recent studies have indicated that autophagy may disease-dependently participate in the pathogenesis of liver diseases, such as liver hepatitis, steatosis, fibrosis, cirrhosis, and hepatocellular carcinoma. This review summarizes the current knowledge on the functions of autophagy in hepatic metabolism and the contribution of autophagy to the pathophysiology of liver-related diseases. Moreover, the impacts of autophagy modulation on the amelioration of the development and progression of liver diseases are also discussed.
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Affiliation(s)
- Po-Yuan Ke
- Department of Biochemistry & Molecular Biology and Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan.
- Liver Research Center, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan.
- Division of Allergy, Immunology, and Rheumatology, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan.
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30
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Zechner R, Madeo F, Kratky D. Cytosolic lipolysis and lipophagy: two sides of the same coin. Nat Rev Mol Cell Biol 2017; 18:671-684. [DOI: 10.1038/nrm.2017.76] [Citation(s) in RCA: 258] [Impact Index Per Article: 36.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Kim S, Yang L, Kim S, Lee RG, Graham MJ, Berliner JA, Lusis AJ, Cai L, Temel RE, Rateri DL, Lee S. Targeting hepatic heparin-binding EGF-like growth factor (HB-EGF) induces anti-hyperlipidemia leading to reduction of angiotensin II-induced aneurysm development. PLoS One 2017; 12:e0182566. [PMID: 28792970 PMCID: PMC5549937 DOI: 10.1371/journal.pone.0182566] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 07/20/2017] [Indexed: 01/02/2023] Open
Abstract
Objective The upregulated expression of heparin binding EGF-like growth factor (HB-EGF) in the vessel and circulation is associated with risk of cardiovascular disease. In this study, we tested the effects of HB-EGF targeting using HB-EGF-specific antisense oligonucleotide (ASO) on the development of aortic aneurysm in a mouse aneurysm model. Approach and results Low-density lipoprotein receptor (LDLR) deficient mice (male, 16 weeks of age) were injected with control and HB-EGF ASOs for 10 weeks. To induce aneurysm, the mice were fed a high fat diet (22% fat, 0.2% cholesterol; w/w) at 5 week point of ASO administration and infused with angiotensin II (AngII, 1,000ng/kg/min) for the last 4 weeks of ASO administration. We confirmed that the HB-EGF ASO administration significantly downregulated HB-EGF expression in multiple tissues including the liver. Importantly, the HB-EGF ASO administration significantly suppressed development of aortic aneurysms including thoracic and abdominal types. Interestingly, the HB-EGF ASO administration induced a remarkable anti-hyperlipidemic effect by suppressing very low density lipoprotein (VLDL) level in the blood. Mechanistically, the HB-EGF targeting suppressed hepatic VLDL secretion rate without changing heparin-releasable plasma triglyceride (TG) hydrolytic activity or fecal neutral cholesterol excretion rate. Conclusion This result suggested that the HB-EGF targeting induced protection against aneurysm development through anti-hyperlipidemic effects. Suppression of hepatic VLDL production process appears to be a key mechanism for the anti-hyperlipidemic effects by the HB-EGF targeting.
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Affiliation(s)
- Seonwook Kim
- Saha Cardiovascular Research Center at the University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
| | - Lihua Yang
- Saha Cardiovascular Research Center at the University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
| | - Seongu Kim
- Saha Cardiovascular Research Center at the University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
| | - Richard G. Lee
- Cardiovascular Antisense Drug Discovery Group at the Ionis Pharmaceuticals, Inc., Carlsbad, California, United States of America
| | - Mark J. Graham
- Cardiovascular Antisense Drug Discovery Group at the Ionis Pharmaceuticals, Inc., Carlsbad, California, United States of America
| | - Judith A. Berliner
- Department of Medicine-Cardiology, University of California-Los Angeles School of Medicine, Los Angeles, California, United States of America
| | - Aldons J. Lusis
- Department of Medicine-Cardiology, University of California-Los Angeles School of Medicine, Los Angeles, California, United States of America
| | - Lei Cai
- Saha Cardiovascular Research Center at the University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
| | - Ryan E. Temel
- Saha Cardiovascular Research Center at the University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
- Department of Pharmacology & Nutritional Sciences at the University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
| | - Debra L. Rateri
- Saha Cardiovascular Research Center at the University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
| | - Sangderk Lee
- Saha Cardiovascular Research Center at the University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
- Department of Pharmacology & Nutritional Sciences at the University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
- * E-mail:
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Affiliation(s)
- Charles E Sparks
- Department of Pathology & Laboratory Medicine, University of Rochester Medical Center, Rochester, New York, USA
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Abstract
PURPOSE OF REVIEW The pathophysiologies of nonalcoholic fatty liver disease (NAFLD), metabolic syndrome, and cardiovascular disease are closely interlinked and associated with atherogenic dyslipidemia. Liver and cardiovascular disease may silently progress to advanced stages if alarming signs, such as abdominal obesity, elevated fasting and postprandial triglycerides, and low HDL cholesterol are overlooked. We review the metabolic mechanisms in NAFLD at the cellular level in the context of standard clinical lipid measurements. RECENT FINDINGS We discuss the pathogenesis of NAFLD, nonalcoholic steatohepatitis (NASH), and metabolic syndrome, atherogenic dyslipidemia, lipotoxicity, and lipophagy. SUMMARY Physicians should infer from biomarkers or clinical findings that their abdominally obese patients are at risk of severe cardiovascular, liver fatty disease, or both. Physicians should carry out laboratory tests of plasma cholesterol, triglycerides, LDL and HDL cholesterol, non-HDL cholesterol, apolipoprotein B and platelets, and for diabetes, but importantly, plasma triglycerides also in the nonfasting state. But note, clinical routine plasma lipid and lipoprotein measurements are not necessarily reliable for interpreting severe metabolic changes. Notably, in advanced stages of NAFLD (i.e., late steatohepatitis and cirrhosis), routine lipid profiles do not necessarily show any more abnormalities.
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Affiliation(s)
- Katriina Nemes
- aUniversity of Helsinki and Helsinki University Central Hospital, Department of Transplantation and Liver Surgery, Helsinki, Finland bUniversity of Helsinki and Helsinki University Central Hospital, Department of Internal Medicine, Helsinki, Finland
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Di Costanzo A, Di Leo E, Noto D, Cefalù AB, Minicocci I, Polito L, D'Erasmo L, Cantisani V, Spina R, Tarugi P, Averna M, Arca M. Clinical and biochemical characteristics of individuals with low cholesterol syndromes: A comparison between familial hypobetalipoproteinemia and familial combined hypolipidemia. J Clin Lipidol 2017; 11:1234-1242. [PMID: 28733173 DOI: 10.1016/j.jacl.2017.06.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 05/27/2017] [Accepted: 06/17/2017] [Indexed: 12/16/2022]
Abstract
BACKGROUND The most frequent monogenic causes of low plasma cholesterol are familial hypobetalipoproteinemia (FHBL1) because of truncating mutations in apolipoprotein B coding gene (APOB) and familial combined hypolipidemia (FHBL2) due to loss-of-function mutations in ANGPTL3 gene. OBJECTIVE A direct comparison of lipid phenotypes of these 2 conditions has never been carried out. In addition, although an increased prevalence of liver steatosis in FHBL1 has been consistently reported, the hepatic consequences of FHBL2 are not well established. METHODS We investigated 350 subjects, 67 heterozygous carriers of APOB mutations, 63 carriers of the p.S17* mutation in ANGPTL3 (57 heterozygotes and 6 homozygotes), and 220 noncarrier normolipemic controls. Prevalence and degree of hepatic steatosis were assessed by ultrasonography. RESULTS A steady decrease of low-density lipoprotein cholesterol levels were observed from heterozygous to homozygous FHBL2 and to FHBL1 individuals, with the lowest levels in heterozygous FHBL1 carrying truncating mutations in exons 1 to 25 of APOB (P for trend <.001). Plasma triglycerides levels were similar in heterozygous FHBL1 and homozygous FHBL2 individuals, but higher in heterozygous FHBL2. The lowest high-density lipoprotein cholesterol levels were detected in homozygous FHBL2 (P for trend <.001). Compared with controls, prevalence and severity of hepatic steatosis were increased in heterozygous FHBL1 (P < .001), but unchanged in FHBL2 individuals. CONCLUSION Truncating APOB mutations showed the more striking low-density lipoprotein cholesterol lowering effect compared with p.S17* mutation in ANGPTL3. Reduced high-density lipoprotein cholesterol levels were the unique lipid characteristic associated with FHBL2. Mutations impairing liver synthesis or secretion of apolipoprotein B are crucial to increase the risk of liver steatosis.
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Affiliation(s)
- Alessia Di Costanzo
- Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy.
| | - Enza Di Leo
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Davide Noto
- Department of Biomedicine, Internal Medicine and Medical Specialties, University of Palermo, Palermo, Italy
| | - Angelo Baldassare Cefalù
- Department of Biomedicine, Internal Medicine and Medical Specialties, University of Palermo, Palermo, Italy
| | - Ilenia Minicocci
- Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy
| | - Luca Polito
- Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy
| | - Laura D'Erasmo
- Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy
| | - Vito Cantisani
- Department of Radiological Sciences, Sapienza University of Rome, Rome, Italy
| | - Rossella Spina
- Department of Biomedicine, Internal Medicine and Medical Specialties, University of Palermo, Palermo, Italy
| | - Patrizia Tarugi
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Maurizio Averna
- Department of Biomedicine, Internal Medicine and Medical Specialties, University of Palermo, Palermo, Italy
| | - Marcello Arca
- Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy
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Zhou L, Hussain MM. Human MicroRNA-548p Decreases Hepatic Apolipoprotein B Secretion and Lipid Synthesis. Arterioscler Thromb Vasc Biol 2017; 37:786-793. [PMID: 28336556 DOI: 10.1161/atvbaha.117.309247] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Accepted: 03/10/2017] [Indexed: 12/31/2022]
Abstract
OBJECTIVE MicroRNAs (miRs) play important regulatory roles in lipid metabolism. Apolipoprotein B (ApoB), as the only essential scaffolding protein in the assembly of very-low-density lipoproteins, is a target to treat hyperlipidemia and atherosclerosis. We aimed to find out miRs that reduce apoB expression. APPROACH AND RESULTS Bioinformatic analyses predicted that hsa-miR-548p can interact with apoB mRNA. MiR-548p or control miR was transfected in human and mouse liver cells to test its role in regulating apoB secretion and mRNA expression levels. Site-directed mutagenesis was used to identify the interacting site of miR-548p in human apoB 3'-untranslated region. Fatty acid oxidation and lipid syntheses were examined in miR-548p overexpressing cells to investigate its function in lipid metabolism. We observed that miR-548p significantly reduces apoB secretion from human hepatoma cells and primary hepatocytes. Mechanistic studies showed that miR-548p interacts with the 3'-untranslated region of human apoB mRNA to enhance post-transcriptional degradation. Bioinformatic algorithms suggested 2 potential binding sites of miR-548p on human apoB mRNA. Site-directed mutagenesis studies revealed that miR-548p targets site I involving both seed and supplementary sequences. MiR-548p had no effect on fatty acid oxidation but significantly decreased lipid synthesis in human hepatoma cells by reducing HMGCR (3-hydroxy-3-methylglutaryl-coenzyme A reductase) and ACSL4 (Acyl-CoA synthetase long-chain family member 4) enzymes involved in cholesterol and fatty acid synthesis. In summary, miR-548p reduces lipoprotein production and lipid synthesis by reducing expression of different genes in human liver cells. CONCLUSIONS These studies suggest that miR-548p regulates apoB secretion by targeting mRNA. It is likely that it could be useful in treating atherosclerosis, hyperlipidemia, and hepatosteatosis.
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Affiliation(s)
- Liye Zhou
- From the School of Graduate Studies, Molecular and Cell Biology Program (L.Z.), and Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, New York (L.Z., M.M.H.); Diabetes and Obesity Research Center, Winthrop University Hospital, Mineola, New York (M.M.H.); and Department of Veterans Affairs, New York Harbor Healthcare System, Brooklyn (M.M.H.)
| | - M Mahmood Hussain
- From the School of Graduate Studies, Molecular and Cell Biology Program (L.Z.), and Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, New York (L.Z., M.M.H.); Diabetes and Obesity Research Center, Winthrop University Hospital, Mineola, New York (M.M.H.); and Department of Veterans Affairs, New York Harbor Healthcare System, Brooklyn (M.M.H.).
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Somatic genome editing with CRISPR/Cas9 generates and corrects a metabolic disease. Sci Rep 2017; 7:44624. [PMID: 28300165 PMCID: PMC5353616 DOI: 10.1038/srep44624] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 02/09/2017] [Indexed: 12/14/2022] Open
Abstract
Germline manipulation using CRISPR/Cas9 genome editing has dramatically accelerated the generation of new mouse models. Nonetheless, many metabolic disease models still depend upon laborious germline targeting, and are further complicated by the need to avoid developmental phenotypes. We sought to address these experimental limitations by generating somatic mutations in the adult liver using CRISPR/Cas9, as a new strategy to model metabolic disorders. As proof-of-principle, we targeted the low-density lipoprotein receptor (Ldlr), which when deleted, leads to severe hypercholesterolemia and atherosclerosis. Here we show that hepatic disruption of Ldlr with AAV-CRISPR results in severe hypercholesterolemia and atherosclerosis. We further demonstrate that co-disruption of Apob, whose germline loss is embryonically lethal, completely prevented disease through compensatory inhibition of hepatic LDL production. This new concept of metabolic disease modeling by somatic genome editing could be applied to many other systemic as well as liver-restricted disorders which are difficult to study by germline manipulation.
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Munkacsi AB, Hammond N, Schneider RT, Senanayake DS, Higaki K, Lagutin K, Bloor SJ, Ory DS, Maue RA, Chen FW, Hernandez-Ono A, Dahlson N, Repa JJ, Ginsberg HN, Ioannou YA, Sturley SL. Normalization of Hepatic Homeostasis in the Npc1nmf164 Mouse Model of Niemann-Pick Type C Disease Treated with the Histone Deacetylase Inhibitor Vorinostat. J Biol Chem 2016; 292:4395-4410. [PMID: 28031458 DOI: 10.1074/jbc.m116.770578] [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] [Received: 12/02/2016] [Revised: 12/21/2016] [Indexed: 12/31/2022] Open
Abstract
Niemann-Pick type C (NP-C) disease is a fatal genetic lipidosis for which there is no Food and Drug Administration (FDA)-approved therapy. Vorinostat, an FDA-approved inhibitor of histone deacetylases, ameliorates lysosomal lipid accumulation in cultured NP-C patient fibroblasts. To assess the therapeutic potential of histone deacetylase inhibition, we pursued these in vitro observations in two murine models of NP-C disease. Npc1nmf164 mice, which express a missense mutation in the Npc1 gene, were treated intraperitoneally, from weaning, with the maximum tolerated dose of vorinostat (150 mg/kg, 5 days/week). Disease progression was measured via gene expression, liver function and pathology, serum and tissue lipid levels, body weight, and life span. Transcriptome analyses of treated livers indicated multiple changes consistent with reversal of liver dysfunction that typifies NP-C disease. Significant improvements in liver pathology and function were achieved by this treatment regimen; however, NPC1 protein maturation and levels, disease progression, weight loss, and animal morbidity were not detectably altered. Vorinostat concentrations were >200 μm in the plasma compartment of treated animals but were almost 100-fold lower in brain tissue. Apolipoprotein B metabolism and the expression of key components of lipid homeostasis in primary hepatocytes from null (Npc1-/-) and missense (Npc1nmf164 ) mutant mice were altered by vorinostat treatment, consistent with a response by these cells independent of the status of the Npc1 locus. These results suggest that HDAC inhibitors have utility to treat visceral NP-C disease. However, it is clear that improved blood-brain barrier penetration will be required to alleviate the neurological symptoms of human NP-C disease.
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Affiliation(s)
- Andrew B Munkacsi
- From the School of Biological Sciences and .,Centre for Biodiscovery, Victoria University of Wellington, Wellington 6012, New Zealand
| | | | | | | | - Katsumi Higaki
- the Division of Functional Genomics, Research Center for Bioscience and Technology, Tottori University, Yonago 683-8503, Japan
| | | | | | - Daniel S Ory
- the Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Robert A Maue
- the Department of Physiology and Neurobiology and the Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755
| | - Fannie W Chen
- the Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York 10029
| | | | - Nicole Dahlson
- the Departments of Physiology and Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390, and
| | - Joyce J Repa
- the Departments of Physiology and Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390, and
| | | | - Yiannis A Ioannou
- the Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York 10029
| | - Stephen L Sturley
- the Department of Genetics and Development, Columbia University Medical Center, New York, New York 10032
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