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Klobučar I, Klobučar L, Lechleitner M, Trbušić M, Pregartner G, Berghold A, Habisch H, Madl T, Frank S, Degoricija V. Associations between Endothelial Lipase and Apolipoprotein B-Containing Lipoproteins Differ in Healthy Volunteers and Metabolic Syndrome Patients. Int J Mol Sci 2023; 24:10681. [PMID: 37445857 PMCID: PMC10341652 DOI: 10.3390/ijms241310681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/23/2023] [Accepted: 06/25/2023] [Indexed: 07/15/2023] Open
Abstract
The association between serum levels of endothelial lipase (EL) and the serum levels and composition of apolipoprotein B (apoB)-containing lipoproteins in healthy subjects and patients with metabolic syndrome (MS) remained unexplored. Therefore, in the present study, we determined the serum levels and lipid content of apoB-containing lipoproteins using nuclear magnetic resonance (NMR) spectroscopy and examined their association with EL serum levels in healthy volunteers (HVs) and MS patients. EL was significantly negatively correlated with the serum levels of cholesterol in large very low-density lipoprotein (VLDL) particles, as well as with total-cholesterol-, free-cholesterol-, triglyceride-, and phospholipid-contents of VLDL and intermediate-density lipoprotein particles in MS patients but not in HVs. In contrast, EL serum levels were significantly positively correlated with the serum levels of apoB, triglycerides, and phospholipids in large low-density lipoprotein particles in HVs but not in MS patients. EL serum levels as well as the serum levels and lipid content of the majority of apoB-containing lipoprotein subclasses were markedly different in MS patients compared with HVs. We conclude that EL serum levels are associated with the serum levels and lipid content of apoB-containing lipoproteins and that these associations are markedly affected by MS.
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Affiliation(s)
- Iva Klobučar
- Department of Cardiology, Sisters of Charity University Hospital Centre, 10000 Zagreb, Croatia; (I.K.); (M.T.)
| | - Lucija Klobučar
- Department of Medicine, University Hospital Centre Osijek, 31000 Osijek, Croatia;
| | - Margarete Lechleitner
- Gottfried Schatz Research Center, Department of Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; (M.L.); (H.H.); (T.M.)
| | - Matias Trbušić
- Department of Cardiology, Sisters of Charity University Hospital Centre, 10000 Zagreb, Croatia; (I.K.); (M.T.)
- School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
| | - Gudrun Pregartner
- Institute for Medical Informatics, Statistics and Documentation, Medical University of Graz, 8036 Graz, Austria; (G.P.); (A.B.)
| | - Andrea Berghold
- Institute for Medical Informatics, Statistics and Documentation, Medical University of Graz, 8036 Graz, Austria; (G.P.); (A.B.)
| | - Hansjörg Habisch
- Gottfried Schatz Research Center, Department of Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; (M.L.); (H.H.); (T.M.)
| | - Tobias Madl
- Gottfried Schatz Research Center, Department of Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; (M.L.); (H.H.); (T.M.)
- BioTechMed-Graz, 8010 Graz, Austria
| | - Saša Frank
- Gottfried Schatz Research Center, Department of Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; (M.L.); (H.H.); (T.M.)
- BioTechMed-Graz, 8010 Graz, Austria
| | - Vesna Degoricija
- School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
- Department of Medicine, Sisters of Charity University Hospital Centre, 10000 Zagreb, Croatia
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2
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Klobučar I, Stadler JT, Klobučar L, Lechleitner M, Trbušić M, Pregartner G, Berghold A, Habisch H, Madl T, Marsche G, Frank S, Degoricija V. Associations between Endothelial Lipase, High-Density Lipoprotein, and Endothelial Function Differ in Healthy Volunteers and Metabolic Syndrome Patients. Int J Mol Sci 2023; 24:2073. [PMID: 36768410 PMCID: PMC9916974 DOI: 10.3390/ijms24032073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/13/2023] [Accepted: 01/17/2023] [Indexed: 01/21/2023] Open
Abstract
Metabolic syndrome (MS) is characterized by endothelial- and high-density lipoprotein (HDL) dysfunction and increased endothelial lipase (EL) serum levels. We examined the associations between EL serum levels, HDL (serum levels, lipid content, and function), and endothelial function in healthy volunteers (HV) and MS patients. Flow-mediated dilation (FMD), nitroglycerin-mediated dilation (NMD), serum levels of HDL subclasses (measured by nuclear magnetic resonance (NMR) spectroscopy), and EL serum levels differed significantly between HV and MS patients. The serum levels of triglycerides in large HDL particles were significantly positively correlated with FMD and NMD in HV, but not in MS patients. Cholesterol (C) and phospholipid (PL) contents of large HDL particles, calculated as HDL1-C/HDL1-apoA-I and HDL1-PL/HDL1-apoA-I, respectively, were significantly negatively correlated with FMD in HV, but not in MS patients. Cholesterol efflux capacity and arylesterase activity of HDL, as well as EL, were correlated with neither FMD nor NMD. EL was significantly negatively correlated with HDL-PL/HDL-apoA-I in HV, but not in MS patients, and with serum levels of small dense HDL containing apolipoprotein A-II in MS patients, but not in HV. We conclude that MS modulates the association between HDL and endothelial function, as well as between EL and HDL. HDL cholesterol efflux capacity and arylesterase activity, as well as EL serum levels, are not associated with endothelial function in HV or MS patients.
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Affiliation(s)
- Iva Klobučar
- Department of Cardiology, Sisters of Charity University Hospital Centre, 10000 Zagreb, Croatia
| | - Julia T. Stadler
- Otto Loewi Research Center, Division of Pharmacology, Medical University of Graz, 8010 Graz, Austria
| | - Lucija Klobučar
- Department of Medicine, University Hospital Centre Osijek, 31000 Osijek, Croatia
| | - Margarete Lechleitner
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria
| | - Matias Trbušić
- Department of Cardiology, Sisters of Charity University Hospital Centre, 10000 Zagreb, Croatia
- School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Gudrun Pregartner
- Institute for Medical Informatics, Statistics und Documentation, Medical University of Graz, 8036 Graz, Austria
| | - Andrea Berghold
- Institute for Medical Informatics, Statistics und Documentation, Medical University of Graz, 8036 Graz, Austria
| | - Hansjörg Habisch
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria
| | - Tobias Madl
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
| | - Gunther Marsche
- Otto Loewi Research Center, Division of Pharmacology, Medical University of Graz, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
| | - Saša Frank
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
| | - Vesna Degoricija
- School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
- Department of Medicine, Sisters of Charity University Hospital Centre, 10000 Zagreb, Croatia
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Zhang Q, Jiang Z, Xu Y. HDL and Oxidation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1377:63-77. [PMID: 35575921 DOI: 10.1007/978-981-19-1592-5_5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In this chapter, we will focus on HDLs' activity of inhibiting LDL oxidation and neutralizing some other oxidants. ApoA-I was known as the main antioxidant component in HDLs. The regulation of antioxidant capacity of HDL is mainly exhibited in regulation of apoA-I and alterations at the level of the HDL lipidome and the modifications of the proteome, especially MPO and PON1. HDL oxidation will influence the processes of inflammation and cholesterol transport, which are important processes in atherosclerosis, metabolic diseases, and many other diseases. In a word, HDL oxidation might be an effective antioxidant target in treatment of many diseases.
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Affiliation(s)
- Qi Zhang
- The Institute of Cardiovascular Sciences and Institute of Systems Biomedicine, School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Science of Ministry of Education, NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Beijing Key Laboratory of Cardiovascular Receptors Research, Health Science Center, Peking University, Beijing, China
| | - Zongzhe Jiang
- Department of Endocrinology and Metabolism, Metabolic Vascular Disease Key Laboratory of Sichuan Province, Sichuan Clinical Research Center for Nephropathy, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China
| | - Yong Xu
- Department of Endocrinology and Metabolism, Metabolic Vascular Disease Key Laboratory of Sichuan Province, Sichuan Clinical Research Center for Nephropathy, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China.
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Lu Y, Cui X, Zhang L, Wang X, Xu Y, Qin Z, Liu G, Wang Q, Tian K, Lim KS, Charles CJ, Zhang J, Tang J. The Functional Role of Lipoproteins in Atherosclerosis: Novel Directions for Diagnosis and Targeting Therapy. Aging Dis 2022; 13:491-520. [PMID: 35371605 PMCID: PMC8947823 DOI: 10.14336/ad.2021.0929] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 09/28/2021] [Indexed: 11/20/2022] Open
Abstract
Dyslipidemia, characterized by a high level of lipids (cholesterol, triglycerides, or both), can increase the risk of developing and progressing atherosclerosis. As atherosclerosis progresses, the number and severity of aterial plagues increases with greater risk of myocardial infarction, a major contributor to cardiovascular mortality. Atherosclerosis progresses in four phases, namely endothelial dysfunction, fatty streak formation, lesion progression and plaque rupture, and eventually thrombosis and arterial obstruction. With greater understanding of the pathological processes underlying atherosclerosis, researchers have identified that lipoproteins play a significant role in the development of atherosclerosis. In particular, apolipoprotein B (apoB)-containing lipoproteins have been shown to associate with atherosclerosis. Oxidized low-density lipoproteins (ox-LDLs) also contribute to the progression of atherosclerosis whereas high-density lipoproteins (HDL) contribute to the removal of cholesterol from macrophages thereby inhibiting the formation of foam cells. Given these known associations, lipoproteins may have potential as biomarkers for predicting risk associated with atherosclerotic plaques or may be targets as novel therapeutic agents. As such, the rapid development of drugs targeting lipoprotein metabolism may lead to novel treatments for atherosclerosis. A comprehensive review of lipoprotein function and their role in atherosclerosis, along with the latest development of lipoprotein targeted treatment, is timely. This review focuses on the functions of different lipoproteins and their involvement in atherosclerosis. Further, diagnostic and therapeutic potential are highlighted giving insight into novel lipoprotein-targetted approaches to treat atherosclerosis.
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Affiliation(s)
- Yongzheng Lu
- Department of Cardiology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.,Key Laboratory of Cardiac Injury and Repair of Henan Province, Zhengzhou, Henan, China.,Henan Province Clinical Research Center for Cardiovascular Diseases, Zhengzhou, Henan, China.
| | - Xiaolin Cui
- Christchurch Regenerative Medicine and Tissue Engineering (CReaTE) group, Department of Orthopedic Surgery, University of Otago, Christchurch 8011, New Zealand.,Department of Bone and Joint, the First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China.
| | - Li Zhang
- Department of Cardiology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.,Key Laboratory of Cardiac Injury and Repair of Henan Province, Zhengzhou, Henan, China.,Henan Province Clinical Research Center for Cardiovascular Diseases, Zhengzhou, Henan, China.
| | - Xu Wang
- Department of Medical Record Management, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
| | - Yanyan Xu
- Department of Cardiology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.,Key Laboratory of Cardiac Injury and Repair of Henan Province, Zhengzhou, Henan, China.,Henan Province Clinical Research Center for Cardiovascular Diseases, Zhengzhou, Henan, China.
| | - Zhen Qin
- Department of Cardiology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.,Key Laboratory of Cardiac Injury and Repair of Henan Province, Zhengzhou, Henan, China.,Henan Province Clinical Research Center for Cardiovascular Diseases, Zhengzhou, Henan, China.
| | - Gangqiong Liu
- Department of Cardiology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.,Key Laboratory of Cardiac Injury and Repair of Henan Province, Zhengzhou, Henan, China.,Henan Province Clinical Research Center for Cardiovascular Diseases, Zhengzhou, Henan, China.
| | - Qiguang Wang
- National Engineering Research Centre for Biomaterials, Sichuan University, Chengdu, Sichuan, China.
| | - Kang Tian
- Department of Bone and Joint, the First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China.
| | - Khoon S Lim
- Christchurch Regenerative Medicine and Tissue Engineering (CReaTE) group, Department of Orthopedic Surgery, University of Otago, Christchurch 8011, New Zealand.
| | - Chris J Charles
- Christchurch Heart Institute, Department of Medicine, University of Otago Christchurch, Christchurch 8011, New Zealand
| | - Jinying Zhang
- Department of Cardiology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.,Key Laboratory of Cardiac Injury and Repair of Henan Province, Zhengzhou, Henan, China.,Henan Province Clinical Research Center for Cardiovascular Diseases, Zhengzhou, Henan, China.
| | - Junnan Tang
- Department of Cardiology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.,Key Laboratory of Cardiac Injury and Repair of Henan Province, Zhengzhou, Henan, China.,Henan Province Clinical Research Center for Cardiovascular Diseases, Zhengzhou, Henan, China.,Correspondence should be addressed to: Dr. Junnan Tang, Department of Cardiology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China.
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Robert J, Osto E, von Eckardstein A. The Endothelium Is Both a Target and a Barrier of HDL's Protective Functions. Cells 2021; 10:1041. [PMID: 33924941 PMCID: PMC8146309 DOI: 10.3390/cells10051041] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/19/2021] [Accepted: 04/26/2021] [Indexed: 12/11/2022] Open
Abstract
The vascular endothelium serves as a barrier between the intravascular and extravascular compartments. High-density lipoproteins (HDL) have two kinds of interactions with this barrier. First, bloodborne HDL must pass the endothelium to access extravascular tissues, for example the arterial wall or the brain, to mediate cholesterol efflux from macrophages and other cells or exert other functions. To complete reverse cholesterol transport, HDL must even pass the endothelium a second time to re-enter circulation via the lymphatics. Transendothelial HDL transport is a regulated process involving scavenger receptor SR-BI, endothelial lipase, and ATP binding cassette transporters A1 and G1. Second, HDL helps to maintain the integrity of the endothelial barrier by (i) promoting junction closure as well as (ii) repair by stimulating the proliferation and migration of endothelial cells and their progenitor cells, and by preventing (iii) loss of glycocalix, (iv) apoptosis, as well as (v) transmigration of inflammatory cells. Additional vasoprotective functions of HDL include (vi) the induction of nitric oxide (NO) production and (vii) the inhibition of reactive oxygen species (ROS) production. These vasoprotective functions are exerted by the interactions of HDL particles with SR-BI as well as specific agonists carried by HDL, notably sphingosine-1-phophate (S1P), with their specific cellular counterparts, e.g., S1P receptors. Various diseases modify the protein and lipid composition and thereby the endothelial functionality of HDL. Thorough understanding of the structure-function relationships underlying the multiple interactions of HDL with endothelial cells is expected to elucidate new targets and strategies for the treatment or prevention of various diseases.
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Affiliation(s)
| | | | - Arnold von Eckardstein
- Institute of Clinical Chemistry, University of Zurich and University Hospital of Zurich, 8091 Zurich, Switzerland; (J.R.); (E.O.)
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6
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Schilcher I, Stadler JT, Lechleitner M, Hrzenjak A, Berghold A, Pregartner G, Lhomme M, Holzer M, Korbelius M, Reichmann F, Springer A, Wadsack C, Madl T, Kratky D, Kontush A, Marsche G, Frank S. Endothelial Lipase Modulates Paraoxonase 1 Content and Arylesterase Activity of HDL. Int J Mol Sci 2021; 22:E719. [PMID: 33450841 PMCID: PMC7828365 DOI: 10.3390/ijms22020719] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/09/2021] [Accepted: 01/11/2021] [Indexed: 01/26/2023] Open
Abstract
Endothelial lipase (EL) is a strong modulator of the high-density lipoprotein (HDL) structure, composition, and function. Here, we examined the impact of EL on HDL paraoxonase 1 (PON1) content and arylesterase (AE) activity in vitro and in vivo. The incubation of HDL with EL-overexpressing HepG2 cells decreased HDL size, PON1 content, and AE activity. The EL modification of HDL did not diminish the capacity of HDL to associate with PON1 when EL-modified HDL was incubated with PON1-overexpressing cells. The overexpression of EL in mice significantly decreased HDL serum levels but unexpectedly increased HDL PON1 content and HDL AE activity. Enzymatically inactive EL had no effect on the PON1 content of HDL in mice. In healthy subjects, EL serum levels were not significantly correlated with HDL levels. However, HDL PON1 content was positively associated with EL serum levels. The EL-induced changes in the HDL-lipid composition were not linked to the HDL PON1 content. We conclude that primarily, the interaction of enzymatically active EL with HDL, rather than EL-induced alterations in HDL size and composition, causes PON1 displacement from HDL in vitro. In vivo, the EL-mediated reduction of HDL serum levels and the consequently increased PON1-to-HDL ratio in serum increase HDL PON1 content and AE activity in mice. In humans, additional mechanisms appear to underlie the association of EL serum levels and HDL PON1 content.
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Affiliation(s)
- Irene Schilcher
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; (I.S.); (M.L.); (M.K.); (A.S.); (T.M.); (D.K.)
| | - Julia T. Stadler
- Otto Loewi Research Center, Division of Pharmacology, Medical University of Graz, Universitätsplatz 4, 8010 Graz, Austria; (J.T.S.); (M.H.); (F.R.); (G.M.)
| | - Margarete Lechleitner
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; (I.S.); (M.L.); (M.K.); (A.S.); (T.M.); (D.K.)
| | - Andelko Hrzenjak
- Division of Pulmonology, Department of Internal Medicine, Medical University of Graz, Auenbruggerplatz 16, 8036 Graz, Austria;
- Ludwig Boltzmann Institute for Lung Vascular Research, Stiftingtalstrasse 24, 8010 Graz, Austria
| | - Andrea Berghold
- Institute for Medical Informatics, Statistics and Documentation, Medical University of Graz, Auenbruggerplatz 2, 8036 Graz, Austria; (A.B.); (G.P.)
| | - Gudrun Pregartner
- Institute for Medical Informatics, Statistics and Documentation, Medical University of Graz, Auenbruggerplatz 2, 8036 Graz, Austria; (A.B.); (G.P.)
| | - Marie Lhomme
- ICANalytics Lipidomics, Institute of Cardiometabolism and Nutrition, 75013 Paris, France;
| | - Michael Holzer
- Otto Loewi Research Center, Division of Pharmacology, Medical University of Graz, Universitätsplatz 4, 8010 Graz, Austria; (J.T.S.); (M.H.); (F.R.); (G.M.)
| | - Melanie Korbelius
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; (I.S.); (M.L.); (M.K.); (A.S.); (T.M.); (D.K.)
| | - Florian Reichmann
- Otto Loewi Research Center, Division of Pharmacology, Medical University of Graz, Universitätsplatz 4, 8010 Graz, Austria; (J.T.S.); (M.H.); (F.R.); (G.M.)
| | - Anna Springer
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; (I.S.); (M.L.); (M.K.); (A.S.); (T.M.); (D.K.)
| | - Christian Wadsack
- Department of Obstetrics and Gynecology, Medical University of Graz, Auenbruggerplatz 14, 8036 Graz, Austria;
- BioTechMed-Graz, Mozartgasse 12/II, 8010 Graz, Austria
| | - Tobias Madl
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; (I.S.); (M.L.); (M.K.); (A.S.); (T.M.); (D.K.)
- BioTechMed-Graz, Mozartgasse 12/II, 8010 Graz, Austria
| | - Dagmar Kratky
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; (I.S.); (M.L.); (M.K.); (A.S.); (T.M.); (D.K.)
- BioTechMed-Graz, Mozartgasse 12/II, 8010 Graz, Austria
| | - Anatol Kontush
- INSERM Research Unit 1166—ICAN, Sorbonne University, 75013 Paris, France;
| | - Gunther Marsche
- Otto Loewi Research Center, Division of Pharmacology, Medical University of Graz, Universitätsplatz 4, 8010 Graz, Austria; (J.T.S.); (M.H.); (F.R.); (G.M.)
- BioTechMed-Graz, Mozartgasse 12/II, 8010 Graz, Austria
| | - Saša Frank
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; (I.S.); (M.L.); (M.K.); (A.S.); (T.M.); (D.K.)
- BioTechMed-Graz, Mozartgasse 12/II, 8010 Graz, Austria
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7
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Radulović S, Gottschalk B, Hörl G, Zardoya-Laguardia P, Schilcher I, Hallström S, Vujić N, Schmidt K, Trieb M, Graier WF, Malli R, Kratky D, Marsche G, Frank S. Endothelial lipase increases eNOS activating capacity of high-density lipoprotein. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158612. [PMID: 31923467 PMCID: PMC7116681 DOI: 10.1016/j.bbalip.2020.158612] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 12/30/2019] [Accepted: 12/31/2019] [Indexed: 12/26/2022]
Abstract
Endothelial lipase (EL) changes structural and functional properties of high-density lipoprotein (HDL). HDL is a relevant modulator of endothelial nitric oxide synthase (eNOS) activity, but the effect of EL on HDL induced eNOS-activation has not yet been investigated. Here, we examined the impact of EL-modified HDL (EL-HDL) on eNOS activity, subcellular trafficking, and eNOS- dependent vasorelaxation. EL-HDL and empty virus (EV)-HDL as control were isolated from human serum incubated with EL-overexpressing or EV infected HepG2 cells. EL-HDL exhibited higher capacity to induce eNOS phosphorylation at Ser1177 and eNOS activity in EA.hy 926 cells, as well as eNOS-dependent vasorelaxation of mouse aortic rings compared to control HDL. As revealed by confocal and structured illumination-microscopy EL-HDL-driven induction of eNOS was accompanied by an increased eNOS-GFP targeting to the plasma membrane and a lower eNOS-GFP colocalization with Golgi and mitochondria. Widefield microscopy of filipin stained cells revealed that EL-HDL lowered cellular free cholesterol (FC) and as found by thin-layer chromatography increased cellular cholesterol ester (CE) content. Additionally, cholesterol efflux capacity, acyl-coenzyme A: cholesterol acyltransferase activity, and HDL particle uptake were comparable between EL-HDL and control HDL. In conclusion, EL increases eNOS activating capacity of HDL, a phenomenon accompanied by an enrichment of the plasma membrane eNOS pool, a decreased cell membrane FC and increased cellular CE content.
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Affiliation(s)
- Snježana Radulović
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Benjamin Gottschalk
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Gerd Hörl
- Otto Loewi Research Center, Division of Physiological Chemistry, Medical University of Graz, Neue Stiftingtalstraße 6/3, 8010 Graz, Austria
| | - Pablo Zardoya-Laguardia
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Irene Schilcher
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Seth Hallström
- Otto Loewi Research Center, Division of Physiological Chemistry, Medical University of Graz, Neue Stiftingtalstraße 6/3, 8010 Graz, Austria
| | - Nemanja Vujić
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Kurt Schmidt
- Department of Pharmacology and Toxicology, University of Graz, Graz, Austria
| | - Markus Trieb
- Otto Loewi Research Center, Division of Experimental and Clinical Pharmacology, Medical University of Graz, Universitätsplatz 4, 8010 Graz, Austria
| | - Wolfgang F Graier
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; BioTechMed-Graz, Mozartgasse 12/II, 8010 Graz, Austria
| | - Roland Malli
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; BioTechMed-Graz, Mozartgasse 12/II, 8010 Graz, Austria
| | - Dagmar Kratky
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; BioTechMed-Graz, Mozartgasse 12/II, 8010 Graz, Austria
| | - Gunther Marsche
- Otto Loewi Research Center, Division of Experimental and Clinical Pharmacology, Medical University of Graz, Universitätsplatz 4, 8010 Graz, Austria; BioTechMed-Graz, Mozartgasse 12/II, 8010 Graz, Austria
| | - Saša Frank
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; BioTechMed-Graz, Mozartgasse 12/II, 8010 Graz, Austria.
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Schilcher I, Ledinski G, Radulović S, Hallström S, Eichmann T, Madl T, Zhang F, Leitinger G, Kolb-Lenz D, Darnhofer B, Birner-Gruenberger R, Wadsack C, Kratky D, Marsche G, Frank S, Cvirn G. Endothelial lipase increases antioxidative capacity of high-density lipoprotein. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:1363-1374. [PMID: 31220617 PMCID: PMC6699986 DOI: 10.1016/j.bbalip.2019.06.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 05/31/2019] [Accepted: 06/14/2019] [Indexed: 12/20/2022]
Abstract
Endothelial lipase (EL) is a strong determinant of structural and functional properties of high-density lipoprotein (HDL). We examined whether the antioxidative capacity of HDL is affected by EL. EL-modified HDL (EL-HDL) and control EV-HDL were generated by incubation of HDL with EL- overexpressing or control HepG2 cells. As determined by native gradient gel electrophoresis, electron microscopy, and small-angle X-ray scattering EL-HDL is smaller than EV-HDL. Mass spectrometry revealed an enrichment of EL-HDL with lipolytic products and depletion of phospholipids and triacylglycerol. Kinetics of conjugated diene formation and HPLC-based malondialdehyde quantification revealed that EL-HDL exhibited a significantly higher resistance to copper ion-induced oxidation and a significantly higher capacity to protect low-density lipoprotein (LDL) from copper ion-induced oxidation when compared to EV-HDL. Depletion of the lipolytic products from EL-HDL abolished the capacity of EL-HDL to protect LDL from copper ion-induced oxidation, which could be partially restored by lysophosphatidylcholine enrichment. Proteomics of HDL incubated with oxidized LDL revealed significantly higher levels of methionine 136 sulfoxide in EL-HDL compared to EV-HDL. Chloramine T (oxidizes methionines and modifies free thiols), diminished the difference between EL-HDL and EV-HDL regarding the capacity to protect LDL from oxidation. In absence of LDL small EV-HDL and EL-HDL exhibited higher resistance to copper ion-induced oxidation when compared to respective large particles. In conclusion, the augmented antioxidative capacity of EL-HDL is primarily determined by the enrichment of HDL with EL-generated lipolytic products and to a lesser extent by the decreased HDL particle size and the increased activity of chloramine T-sensitive mechanisms.
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Affiliation(s)
- Irene Schilcher
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Gerhard Ledinski
- Otto Loewi Research Center, Division of Physiological Chemistry, Medical University of Graz, Neue Stiftingtalstraße 6/3, 8010 Graz, Austria
| | - Snježana Radulović
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Seth Hallström
- Otto Loewi Research Center, Division of Physiological Chemistry, Medical University of Graz, Neue Stiftingtalstraße 6/3, 8010 Graz, Austria
| | - Thomas Eichmann
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria; Center for Explorative Lipidomics, BioTechMed-Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Tobias Madl
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; BioTechMed-Graz, Mozartgasse 12/II, 8010 Graz, Austria; Omics Center Graz, BioTechMed-Graz, Stiftingtalstrasse 24, 8010 Graz, Austria
| | - Fangrong Zhang
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Gerd Leitinger
- Gottfried Schatz Research Center, Department of Cell Biology, Histology and Embryology. Center for Medical Research, Medical University of Graz, Neue Stiftingtalstraße 6/3, 8010 Graz, Austria
| | - Dagmar Kolb-Lenz
- Gottfried Schatz Research Center, Department of Cell Biology, Histology and Embryology. Center for Medical Research, Medical University of Graz, Neue Stiftingtalstraße 6/3, 8010 Graz, Austria
| | - Barbara Darnhofer
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; BioTechMed-Graz, Mozartgasse 12/II, 8010 Graz, Austria; Omics Center Graz, BioTechMed-Graz, Stiftingtalstrasse 24, 8010 Graz, Austria; Austrian Center of Industrial Biotechnology, Petersgasse 14, A-8010 Graz, Austria
| | - Ruth Birner-Gruenberger
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; BioTechMed-Graz, Mozartgasse 12/II, 8010 Graz, Austria; Omics Center Graz, BioTechMed-Graz, Stiftingtalstrasse 24, 8010 Graz, Austria; Austrian Center of Industrial Biotechnology, Petersgasse 14, A-8010 Graz, Austria
| | - Christian Wadsack
- BioTechMed-Graz, Mozartgasse 12/II, 8010 Graz, Austria; Department of Obstetrics and Gynecology, Medical University of Graz, Auenbruggerplatz 14, 8036 Graz, Austria
| | - Dagmar Kratky
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; BioTechMed-Graz, Mozartgasse 12/II, 8010 Graz, Austria
| | - Gunther Marsche
- BioTechMed-Graz, Mozartgasse 12/II, 8010 Graz, Austria; Otto Loewi Research Center, Division of Pharmacology, Medical University of Graz, Universitätsplatz 4, 8010 Graz, Austria
| | - Saša Frank
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; BioTechMed-Graz, Mozartgasse 12/II, 8010 Graz, Austria.
| | - Gerhard Cvirn
- Otto Loewi Research Center, Division of Physiological Chemistry, Medical University of Graz, Neue Stiftingtalstraße 6/3, 8010 Graz, Austria
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9
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Arnao V, Tuttolomondo A, Daidone M, Pinto A. Lipoproteins in Atherosclerosis Process. Curr Med Chem 2019; 26:1525-1543. [PMID: 31096892 DOI: 10.2174/0929867326666190516103953] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 11/17/2017] [Accepted: 12/10/2017] [Indexed: 01/15/2023]
Abstract
BACKGROUND Dyslipidaemias is a recognized risk factor for atherosclerosis, however, new evidence brought to light by trials investigating therapies to enhance HDLcholesterol have suggested an increased atherosclerotic risk when HDL-C is high. RESULTS Several studies highlight the central role in atherosclerotic disease of dysfunctional lipoproteins; oxidised LDL-cholesterol is an important feature, according to "oxidation hypothesis", of atherosclerotic lesion, however, there is today a growing interest for dysfunctional HDL-cholesterol. The target of our paper is to review the functions of modified and dysfunctional lipoproteins in atherogenesis. CONCLUSION Taking into account the central role recognized to dysfunctional lipoproteins, measurements of functional features of lipoproteins, instead of conventional routine serum evaluation of lipoproteins, could offer a valid contribution in experimental studies as in clinical practice to stratify atherosclerotic risk.
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Affiliation(s)
- Valentina Arnao
- BioNeC Dipartimento di BioMedicina Sperimentale e Neuroscienze Cliniche, Universita degli Studi di Palermo, Palermo, Italy.,PhD School of: Medicina Clinica e Scienze del Comportamento-Biomedical Department of Internal and Specialistic Medicine. (Di.Bi.M.I.S), University of Palermo, Palermo, Italy
| | - Antonino Tuttolomondo
- Internal Medicine and Stroke Care Ward, Department of Health Promotion Sciences, Maternal and Infant Care, Internal Medicine and Medical Specialties, (PROMISE), University of Palermo, Palermo, Italy
| | - Mario Daidone
- Internal Medicine and Stroke Care Ward, Department of Health Promotion Sciences, Maternal and Infant Care, Internal Medicine and Medical Specialties, (PROMISE), University of Palermo, Palermo, Italy
| | - Antonio Pinto
- Internal Medicine and Stroke Care Ward, Department of Health Promotion Sciences, Maternal and Infant Care, Internal Medicine and Medical Specialties, (PROMISE), University of Palermo, Palermo, Italy
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10
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Mathew AV, Yu J, Guo Y, Byun J, Chen YE, Wang L, Liu M, Bard RL, Morishita M, Huang W, Li J, Harkema JR, Rajagopalan S, Pennathur S, Brook RD. Effect of Ambient Fine Particulate Matter Air Pollution and Colder Outdoor Temperatures on High-Density Lipoprotein Function. Am J Cardiol 2018; 122:565-570. [PMID: 30005891 PMCID: PMC6133768 DOI: 10.1016/j.amjcard.2018.04.061] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 04/23/2018] [Accepted: 04/30/2018] [Indexed: 12/13/2022]
Abstract
Fine particulate matter (PM2.5) air pollution and environmental temperatures influence cardiovascular morbidity and mortality. Recent evidence suggests that several air pollutants can promote dyslipidemia; however, the impact of ambient PM2.5 and temperature on high-density lipoprotein (HDL) function remains unclear. We hypothesized that daily exposures to higher levels of ambient PM2.5 and colder outdoor temperatures would impair HDL functionality. Lipoproteins, serum cholesterol efflux capacity (CEC), and HDL oxidation markers were measured twice in 50 healthy adults (age 32.1 ± 9.6 years) living in southeast Michigan and associated with ambient and personal-level exposures using mixed models. Although previous 7-day mean outdoor temperature (4.4 ± 9.8°C) and PM2.5 levels (9.1 ± 1.8 µg/m3) were low, higher ambient PM2.5 exposures (per 10 µg/m3) were associated with significant increases in the total cholesterol-to-HDL-C ratio (rolling average lag days 1 and 2) as well as reductions in CEC by -1.93% (lag day 5, p = 0.022) and -1.62% (lag day 6, p = 0.032). Colder outdoor temperatures (per 10°C) were also associated with decreases in CEC from -0.62 to -0.63% (rolling average lag days 5 and 7, p = 0.027 and 0.028). Previous 24-hour personal-level PM2.5 and temperature exposures did not impact outcomes, nor were any exposures associated with changes in HDL-oxidation metrics. In conclusion, we provide the first evidence that ambient PM2.5 (even at low levels) and outdoor temperatures may influence serum CEC, a critical antiatherosclerotic HDL function.
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Affiliation(s)
- Anna Vachaparampil Mathew
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan.
| | - Joyce Yu
- University of Michigan, Ann Arbor, Michigan
| | - Yanhong Guo
- Division of Cardiology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Jaeman Byun
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Y Eugene Chen
- Division of Cardiology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan; Department of Cardiac Surgery, University of Michigan, Ann Arbor, Michigan
| | - Lu Wang
- School of Public Health, University of Michigan, Ann Arbor, Michigan
| | - Mochuan Liu
- School of Public Health, University of Michigan, Ann Arbor, Michigan
| | - Robert L Bard
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, Michigan
| | - Masako Morishita
- Department of Family Medicine, Michigan State University, East Lansing, Michigan
| | - Wei Huang
- Department of Occupational and Environmental Health, Peking University School of Public Health, Beijing, China
| | - Jianping Li
- Division of Cardiology, Peking University First Hospital, Beijing, China
| | - Jack R Harkema
- Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan
| | - Sanjay Rajagopalan
- Division of Cardiovascular Medicine, Case Western Reserve Medical School, Cleveland, Ohio
| | - Subramaniam Pennathur
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Robert D Brook
- Division of Cardiology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
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11
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Schilcher I, Kern S, Hrzenjak A, Eichmann TO, Stojakovic T, Scharnagl H, Duta-Mare M, Kratky D, Marsche G, Frank S. Impact of Endothelial Lipase on Cholesterol Efflux Capacity of Serum and High-density Lipoprotein. Sci Rep 2017; 7:12485. [PMID: 28970555 PMCID: PMC5624901 DOI: 10.1038/s41598-017-12882-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 08/15/2017] [Indexed: 12/31/2022] Open
Abstract
Endothelial lipase (EL) is a potent modulator of the structural and functional properties of HDL. Impact of EL on cholesterol efflux capacity (CEC) of serum and isolated HDL is not well understood and apparently contradictory data were published. Here, we systematically examined the impact of EL on composition and CEC of serum and isolated HDL, in vitro and in vivo, using EL-overexpressing cells and EL-overexpressing mice. CEC was examined in a validated assay using 3H-cholesterol labelled J774 macrophages. In vitro EL-modification of serum resulted in complex alterations, including enrichment of serum with lipid-free/-poor apoA-I, decreased size of human (but not mouse) HDL and altered HDL lipid composition. EL-modification of serum increased CEC, in line with increased lipid-free/-poor apoA-I formation. In contrast, CEC of isolated HDL was decreased likely through altered lipid composition. In contrast to in vitro results, EL-overexpression in mice markedly decreased HDL-cholesterol and apolipoprotein A-I serum levels associated with a decreased CEC of serum. HDL lipid composition was altered, but HDL particle size and CEC were not affected. Our study highlights the multiple and complex effects of EL on HDL composition and function and may help to clarify the seemingly contradictory data found in published articles.
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Affiliation(s)
- Irene Schilcher
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University Graz, Neue Stiftingtalstraße 6/6, 8010, Graz, Austria
| | - Sabine Kern
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Universitätsplatz 4, 8010, Graz, Austria
| | - Andelko Hrzenjak
- Division of Pulmonology, Department of Internal Medicine, Medical University of Graz, Auenbruggerplatz 20, 8036, Graz, Austria.,Ludwig Boltzmann Institute for Lung Vascular Research, Stiftingtalstrasse 24, 8010, Graz, Austria
| | - Thomas O Eichmann
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010, Graz, Austria
| | - Tatjana Stojakovic
- Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Auenbruggerplatz 15, 8036, Graz, Austria
| | - Hubert Scharnagl
- Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Auenbruggerplatz 15, 8036, Graz, Austria
| | - Madalina Duta-Mare
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University Graz, Neue Stiftingtalstraße 6/6, 8010, Graz, Austria
| | - Dagmar Kratky
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University Graz, Neue Stiftingtalstraße 6/6, 8010, Graz, Austria.,BioTechMed-Graz, Graz, Austria
| | - Gunther Marsche
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Universitätsplatz 4, 8010, Graz, Austria. .,BioTechMed-Graz, Graz, Austria.
| | - Saša Frank
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University Graz, Neue Stiftingtalstraße 6/6, 8010, Graz, Austria. .,BioTechMed-Graz, Graz, Austria.
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12
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Metabolic Syndrome Modulates Association between Endothelial Lipase and Lipid/Lipoprotein Plasma Levels in Acute Heart Failure Patients. Sci Rep 2017; 7:1165. [PMID: 28446761 PMCID: PMC5430647 DOI: 10.1038/s41598-017-01367-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 03/29/2017] [Indexed: 01/04/2023] Open
Abstract
We hypothesised that the established association of endothelial lipase (EL) plasma levels with atherogenic lipid profile is altered in acute heart failure (AHF) and additionally affected by overlapping metabolic syndrome (MetS). We examined the association of EL plasma levels and lipid/lipoprotein plasma levels in AHF patients without and with overlapping MetS. The study was performed as a single-centre, observational study on 152 AHF patients, out of which 85 had overlapping MetS. In the no-MetS group, EL plasma levels were significantly positively correlated with plasma levels of atherogenic lipids/lipoproteins, including total cholesterol, low-density lipoprotein (LDL)-cholesterol, total LDL particles and triglycerides, but also with plasma levels of antiatherogenic high-density lipoprotein (HDL)-cholesterol, total HDL particles and small HDL particles. In the MetS group, EL plasma levels were positively correlated with triglyceride and small LDL-particle levels, and significantly negatively correlated with plasma levels of large HDL particles as well as with LDL- and HDL-particle size, respectively. EL- and lipid/lipoprotein- plasma levels were different in the no-MetS patients, compared to MetS patients. The association of EL with atherogenic lipid profile is altered in AHF and additionally modified by MetS, which strongly modulates EL- and lipid/lipoprotein-plasma levels in AHF.
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13
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Abstract
Aims/Introduction: Endothelial lipase (EL) plays an important role in high‐density lipoprotein (HDL) metabolism and experimental data suggest that EL might be proatherogenic. We have investigated whether serum EL concentration is associated with changes in serum capacity to induce cholesterol efflux and arterial stiffness in type 2 diabetes. Materials and Methods: Serum EL was assayed by ELISA in 172 diabetic patients and 175 controls. The ability of serum to induce cholesterol efflux was measured using a cell culture system and arterial stiffness was determined by measuring pulse wave velocity (PWV) between carotid and femoral arteries. Results: Diabetic patients had significantly higher C‐reactive protein (CRP) and EL (27.7 ± 16.6 ng/mL vs 24.0 ± 11.3, P < 0.05). Cholesterol efflux to serum mediated through scavenger receptor class B type I was impaired (15.1 ± 2.5%vs 16.7 ± 3.1, respectively, P < 0.01). In controls, serum EL correlated with cholesterol efflux to serum (r = −0.16, P = 0.025), but only a trend was seen in the diabetic patients. Linear regression showed that in controls, HDL, serum EL and waist circumference were major independent determinants of cholesterol efflux; whereas in the diabetic cohort, the major independent determinants of cholesterol efflux were HDL, CRP and age. PWV was increased in the diabetic patients (P < 0.01), but no association between serum EL and PWV was seen in either groups. Conclusions: Serum EL was increased in diabetic patients, but impaired serum capacity to induce cholesterol efflux in these patients was mainly related to low HDL and subclinical inflammation. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2010.00016.x, 2010)
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Affiliation(s)
- Sammy Wm Shiu
- Department of Medicine, University of Hong Kong, Hong Kong
| | - Huali Zhou
- Department of Medicine, University of Hong Kong, Hong Kong
| | - Ying Wong
- Department of Medicine, University of Hong Kong, Hong Kong
| | - Kathryn Cb Tan
- Department of Medicine, University of Hong Kong, Hong Kong
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14
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Nishimukai M, Maeba R, Yamazaki Y, Nezu T, Sakurai T, Takahashi Y, Hui SP, Chiba H, Okazaki T, Hara H. Serum choline plasmalogens, particularly those with oleic acid in sn-2, are associated with proatherogenic state. J Lipid Res 2014; 55:956-65. [PMID: 24616482 DOI: 10.1194/jlr.p045591] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Serum plasmalogens (Pls) (1-O-alk-1'-enyl-2-acyl glycerophospholipids) are of particular interest for studies on metabolic disorders associated with oxidative stress and chronic inflammation. Serum levels of Pls are known to correlate positively with HDL-cholesterol (HDL-C); however, few studies have examined serum Pls molecular species in association with pathophysiological conditions and their clinical significance. To clarify these, we determined serum levels of individual ether glycerophospholipids in Japanese asymptomatic cohorts (n = 428; 362 male and 66 female subjects) by LC/MS/MS, and examined their correlations with clinical parameters. We found that the proportion of choline Pls (PlsCho) among total serum phospholipids was significantly lower in the male group over 40 years old and was associated with multiple risk parameters more strongly than HDL-C. The abundance of serum PlsCho with oleic acid (18:1) in sn-2 exhibited the strongest positive correlation with serum concentrations of adiponectin and HDL-C, while being inversely associated with waist circumference and the serum levels of TG and small dense LDL-cholesterol. The characterization of serum ether glycerophospholipids verified the specificity of PlsCho, particularly the ones with 18:1 in sn-2, as a sensitive biomarker for the atherogenic state.
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Affiliation(s)
- Megumi Nishimukai
- Division of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
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15
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Lee-Rueckert M, Kovanen PT. Extracellular modifications of HDL in vivo and the emerging concept of proteolytic inactivation of preβ-HDL. Curr Opin Lipidol 2011; 22:394-402. [PMID: 21881503 DOI: 10.1097/mol.0b013e32834a3d24] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
PURPOSE OF REVIEW Both quantity and quality of the circulating HDL particle matter for the optimal antiatherogenic potential of HDL. This review summarizes various mechanisms capable of inducing extracellular modifications of HDL and reducing the function of HDL subclasses as cholesterol acceptors. Special emphasis is laid on the proteolytic inactivation of lipid-poor preβ-migrating HDL (preβ-HDL). RECENT FINDINGS HDL particles can undergo functional inactivation in vivo. During atherogenesis, different cell types in the arterial intima release enzymes into the intimal fluid, potentially capable of causing structural and chemical modifications of the various components present in the lipid core or in the polar surface of the HDL particles. Enzymatic oxidation, lipolysis and proteolysis, and nonenzymatic glycosylation are among the HDL modifications that adversely affect HDL functionality. Proteolysis of preβ-HDL by various proteases present in the arterial intima has emerged as a potential mechanism that impairs the efficiency of HDL to promote cholesterol efflux from macrophage foam cells, the mast cell-derived neutral protease chymase being a prime example of such impairment. A paradigm of proteolytic inactivation of preβ-HDL in vivo is emerging. SUMMARY Several extracellular enzymes present in the arterial intima may compromise various cardioprotective functions of HDL. Observations on proteolysis of specific lipid-poor HDL subpopulations in vivo constitute the basis for future studies evaluating the actual impact of proteolytic microenvironments on the initiation and progression of atherosclerotic lesions.
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16
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Role of hepatic lipase and endothelial lipase in high-density lipoprotein-mediated reverse cholesterol transport. Curr Atheroscler Rep 2011; 13:257-65. [PMID: 21424685 PMCID: PMC3085744 DOI: 10.1007/s11883-011-0175-2] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Reverse cholesterol transport (RCT) constitutes a key part of the atheroprotective properties of high-density lipoproteins (HDL). Hepatic lipase (HL) and endothelial lipase (EL) are negative regulators of plasma HDL cholesterol levels. Although overexpression of EL decreases overall macrophage-to-feces RCT, knockout of both HL and EL leaves RCT essentially unaffected. With respect to important individual steps of RCT, current data on the role of EL and HL in cholesterol efflux are not conclusive. Both enzymes increase hepatic selective cholesterol uptake; however, this does not translate into altered biliary cholesterol secretion, which is regarded the final step of RCT. Also, the impact of HL and EL on atherosclerosis is not clear cut; rather it depends on respective experimental conditions and chosen models. More mechanistic insights into the diverse biological properties of these enzymes are therefore required to firmly establish EL and HL as targets for the treatment of atherosclerotic cardiovascular disease.
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17
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Darrow AL, Olson MW, Xin H, Burke SL, Smith C, Schalk-Hihi C, Williams R, Bayoumy SS, Deckman IC, Todd MJ, Damiano BP, Connelly MA. A novel fluorogenic substrate for the measurement of endothelial lipase activity. J Lipid Res 2011; 52:374-82. [PMID: 21062953 DOI: 10.1194/jlr.d007971] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Endothelial lipase (EL) is a phospholipase A1 (PLA1) enzyme that hydrolyzes phospholipids at the sn-1 position to produce lysophospholipids and free fatty acids. Measurement of the PLA1 activity of EL is usually accomplished by the use of substrates that are also hydrolyzed by lipases in other subfamilies such as PLA2 enzymes. In order to distinguish PLA1 activity of EL from PLA2 enzymatic activity in cell-based assays, cell supernatants, and other nonhomogeneous systems, a novel fluorogenic substrate with selectivity toward PLA1 hydrolysis was conceived and characterized. This substrate was preferred by PLA1 enzymes, such as EL and hepatic lipase, and was cleaved with much lower efficiency by lipases that exhibit primarily triglyceride lipase activity, such as LPL or a lipase with PLA2 activity. The phospholipase activity detected by the PLA1 substrate could be inhibited with the small molecule esterase inhibitor ebelactone B. Furthermore, the PLA1 substrate was able to detect EL activity in human umbilical vein endothelial cells in a cell-based assay. This substrate is a useful reagent for identifying modulators of PLA1 enzymes, such as EL, and aiding in characterizing their mechanisms of action.
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Affiliation(s)
- Andrew L Darrow
- Pharmaceutical Research and Development, Johnson & Johnson LLC , Spring House, PA 19477-0776, USA
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18
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Hara T, Ishida T, Kojima Y, Tanaka H, Yasuda T, Shinohara M, Toh R, Hirata KI. Targeted deletion of endothelial lipase increases HDL particles with anti-inflammatory properties both in vitro and in vivo. J Lipid Res 2010; 52:57-67. [PMID: 20926433 DOI: 10.1194/jlr.m008417] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Previous studies have shown that targeted deletion of endothelial lipase (EL) markedly increases the plasma high density lipoprotein cholesterol (HDL-C) level in mice. However, little is known about the functional quality of HDL particles after EL inhibition. Therefore, the present study assessed the functional quality of HDL isolated from EL(-/-) and wild-type (WT) mice. Anti-inflammatory functions of HDL from EL(-/-) and WT mice were evaluated by in vitro assays. The HDL functions such as PON-1 or PAF-AH activities, inhibition of cytokine-induced vascular cell adhesion molecule-1 expression, inhibition of LDL oxidation, and the ability of cholesterol efflux were similar in HDL isolated from WT and EL(-/-) mice. In contrast, the lipopolysaccharide-neutralizing capacity of HDL was significantly higher in EL(-/-) mice than that in WT mice. To evaluate the anti-inflammatory actions of HDL in vivo, lipopolysaccharide-induced systemic inflammation was generated in these mice. EL(-/-) mice showed higher survival rate and lower expression of inflammatory markers than WT mice. Intravenous administration of HDL isolated from EL(-/-) mice significantly improved the mortality after lipopolysaccharide injection in WT mice. In conclusion, targeted disruption of EL increased HDL particles with preserved anti-inflammatory and anti-atherosclerotic functions. Thus, EL inhibition would be a useful strategy to raise 'good' cholesterol in the plasma.
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Affiliation(s)
- Tetsuya Hara
- Division of Cardiovascular Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
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19
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Abstract
PURPOSE OF REVIEW To address the progress of the investigation on dysfunctional high-density lipoprotein (HDL). RECENT FINDINGS HDL is generally considered to be an independent protective factor against cardiovascular disease. However, emerging evidence indicates that HDL can be modified under certain circumstances and lose its protective effect or even become atherogenic. The underlying mechanisms responsible for generating the dysfunctional HDL and the chemical and structural changes of HDL remain largely unknown. Recent studies focus on the role of myeloperoxidase in generating oxidants as participants in rendering HDL dysfunctional in vivo. Myeloperoxidase modifies HDL in humans by oxidation of specific amino acid residues in apolipoprotein A-I, which impairs cholesterol efflux through ATP-binding cassette transporter A1 and contributes to atherogenesis. SUMMARY HDL may not always be atheroprotective and can be atherogenic paradoxically under certain conditions. The mechanisms responsible for generating the dysfunctional HDL remain largely unknown. Recent data suggest that myeloperoxidase-associated modification of HDL may be one of the mechanisms. Further studies are needed to investigate the in-vivo mechanisms of HDL modification and identify therapeutic approaches aiming at controlling HDL modification.
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Affiliation(s)
- Hong Feng
- Kentucky Pediatric Research Institute, Department of Pediatrics, University of Kentucky Medical Center, Lexington, Kentucky 40536, USA
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Qiu G, Hill JS. Endothelial lipase promotes apolipoprotein AI-mediated cholesterol efflux in THP-1 macrophages. Arterioscler Thromb Vasc Biol 2008; 29:84-91. [PMID: 18988890 DOI: 10.1161/atvbaha.108.176487] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Endothelial lipase (EL) is expressed by macrophages within atherosclerotic lesions. We investigated the influence of EL expression on cholesterol efflux in macrophages. METHODS AND RESULTS The present study used lentivirus to introduce either EL shRNA for loss-of-function studies or EL cDNA for gain-of-function studies to investigate the role of EL in apoAI-mediated cholesterol efflux. ApoAI-mediated cholesterol efflux was decreased after EL suppression, but increased with EL overexpression in free cholesterol labeled and acLDL loaded THP-1 macrophages. Similar findings were observed in THP-1 macrophages after exogenous EL addition and in transfected 293 cells. EL-related apoAI-mediated cholesterol efflux decreased after treatment with heparin or catalytic inactivation (S149A mutation or tetrahydrolipstatin) alone, and completely inhibited in combination. Furthermore, EL expression did not change ABCA1 expression, but was positively correlated with apoAI binding to macrophages and 293 cells. This effect was mitigated after heparin treatment but not influenced by catalytic inactivation via tetrahydrolipstatin or the S149A mutation. Moreover, EL expression was positively associated with lysophosphatidylcholine production and inversely with phosphatidylcholine, phosphatidylethanolamine, and sphingomyelin levels. Lysophosphatidylcholine treatment dose-dependently stimulated apoAI-mediated cholesterol efflux in THP-1 macrophages. CONCLUSIONS EL appears to promote apoAI-mediated cholesterol efflux through catalytic and noncatalytic-dependent mechanisms.
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Affiliation(s)
- Guosong Qiu
- James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, Providence Heart+Lung Institute, Department of Pathology and Laboratory Medicine, University of British Columbia-St. Paul's Hospital, Vancouver, BC Canada
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21
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Abstract
PURPOSE OF REVIEW Several in-vitro and in-vivo animal studies indicate that endothelial lipase plays a key role in the intravascular remodeling of lipoproteins, particularly HDL. This review integrates this body of knowledge with more recent data in humans linking endothelial lipase to HDL metabolism and other features of the metabolic syndrome. RECENT FINDINGS Human studies generally support the involvement of endothelial lipase in modulating plasma HDL. The association between endothelial lipase and metabolism of apolipoprotein B-containing lipoproteins in humans, however, has not been entirely consistent with previous findings in vitro and in animals. Finally, elevated plasma endothelial lipase has been associated with abdominal obesity and hypertension, and there is now compelling evidence that inflammation and in-vivo regulation of endothelial lipase may be intrinsically related. SUMMARY Accumulating evidence indicates that endothelial lipase plays a role in the etiology of the atherogenic plasma lipoprotein profile characteristic of the metabolic syndrome. Increased endothelial lipase activity is linked to the underlying proinflammatory state in this condition. Further studies are required, however, to define the extent to which endothelial lipase contributes to the dyslipidemia of the metabolic syndrome relative to other important regulating factors, such as lipoprotein lipase, hepatic lipase, and cholesterol ester transfer protein.
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Affiliation(s)
- Benoît Lamarche
- Institute on Nutraceuticals and Functional Foods, Laval University, Québec, Canada.
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22
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Pownall HJ. Detergent-mediated phospholipidation of plasma lipoproteins increases HDL cholesterophilicity and cholesterol efflux via SR-BI. Biochemistry 2006; 45:11514-22. [PMID: 16981711 PMCID: PMC2556864 DOI: 10.1021/bi0608717] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cellular cholesterol efflux is an early, obligatory step in reverse cholesterol transport, the putative antiatherogenic mechanism by which human plasma high-density lipoproteins (HDL) transport cholesterol from peripheral tissue to the liver for recycling or disposal. HDL-phospholipid content is the essential cholesterol-binding component of lipoproteins and therefore a major determinant of cholesterol efflux. Thus, increased phospholipidation of lipoproteins, particularly HDL, is one strategy for increasing cholesterol efflux. This study validates a simple, new detergent perturbation method for the phospholipidation of plasma lipoproteins; we have quantified the cholesterophilicity of human plasma lipoproteins and the effects of lipoprotein phospholipidation on cholesterophilicity and cellular cholesterol efflux mediated by the class B type I scavenger receptor (SR-BI). We determined that low-density lipoproteins (LDL) are more cholesterophilic than HDL and that LDL has a higher affinity for phospholipids than HDL whereas HDL has a higher phospholipid capacity than LDL. Phospholipidation of total human plasma lipoproteins enhances cholesterol efflux, an effect that occurs largely through the preferential phospholipidation of HDL. We conclude that increasing HDL phospholipid increases its cholesterophilicity, thereby making it a better acceptor of cellular cholesterol efflux. Phospholipidation of lipoproteins by detergent perturbation is a simple way to increase HDL cholesterophilicity and cholesterol efflux in a way that may be clinically useful.
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Affiliation(s)
- Henry J Pownall
- Section of Atherosclerosis and Lipoprotein Research, Department of Medicine, Baylor College of Medicine, Houston, Texas 77030, USA.
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Norata GD, Pirillo A, Catapano AL. Modified HDL: biological and physiopathological consequences. Nutr Metab Cardiovasc Dis 2006; 16:371-386. [PMID: 16829346 DOI: 10.1016/j.numecd.2006.01.012] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2005] [Accepted: 01/03/2006] [Indexed: 01/26/2023]
Abstract
Epidemiological and clinical studies have demonstrated the inverse association between HDL cholesterol levels (HDL-C) and the risk of coronary heart disease (CHD). This correlation is believed to relate to the ability of HDL to promote reverse cholesterol transport. Remodeling of HDL due to chemical/physical modifications can dramatically affect its functions, leading to dysfunctional HDL that could promote atherogenesis. HDL modification can be achieved by different means: (i) non-enzymatic modifications, owing to the presence of free metal ions in the atherosclerotic plaques; (ii) cell-associated enzymes, which can degrade the apoproteins without significant changes in the lipid moiety, or can alternatively induce apoprotein cross-linking and lipid oxidation; (iii) association with acute phase proteins, whose circulating levels are significantly increased during inflammation which may modify HDL structure and functions; and (iv) metabolic modifications, such as glycation that occurs under hyperglycaemic conditions. Available data suggest that HDL can easily be modified losing their anti-atherogenic activities. These observation results mainly from in vitro studies, while few in vivo data, are available. Furthermore the in vivo mechanisms involved in HDL modification are ill understood. A better knowledge of these pathways may provide possible therapeutic target aimed at reducing HDL modification.
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Gauster M, Hrzenjak A, Schick K, Frank S. Endothelial lipase is inactivated upon cleavage by the members of the proprotein convertase family. J Lipid Res 2005; 46:977-87. [PMID: 15722560 DOI: 10.1194/jlr.m400500-jlr200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Mature endothelial lipase (EL) is a 68 kDa glycoprotein. In HepG2 cells infected with adenovirus encoding human EL, the mature EL was detectable in the cell lysates and heparin-releasable fractions. In contrast, cell media of these cells contained two EL fragments: an N-terminal 40 kDa fragment and a C-terminal 28 kDa fragment. N-terminal protein sequencing of the His-tagged 28 kDa fragment revealed that EL is cleaved on the C terminus of the sequence RNKR330, the consensus cleavage sequence for mammalian proprotein convertases (pPCs). Replacement of Arg-330 with Ser by site-directed mutagenesis totally abolished EL processing. EL processing could efficiently be attenuated by specific inhibitors of pPCs, alpha1-antitrypsin Portland (alpha1-PDX) and alpha1-antitrypsin variant AVRR. Coexpression of the pPCs furin, PC6A, and PACE4 with EL resulted in a complete conversion of the full-length EL to a truncated 40 kDa fragment. Exogenously added EL was also processed by cells, and the processing could be attenuated by alpha1-PDX. The expressed N-terminal 40 kDa fragment of EL (EL-40) harboring the catalytic site failed to hydrolyze [14C]NEFA from [14C]dipalmitoyl-PC-labeled HDL. EL-40 was incapable of bridging 125I-labeled HDL to the cells and had no impact on plasma lipid concentration when overexpressed in mice. Thus, our results demonstrate that pPCs are involved in the inactivation process of EL.
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Affiliation(s)
- Martin Gauster
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University, Graz A-8010, Austria
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25
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Gauster M, Rechberger G, Sovic A, Hörl G, Steyrer E, Sattler W, Frank S. Endothelial lipase releases saturated and unsaturated fatty acids of high density lipoprotein phosphatidylcholine. J Lipid Res 2005; 46:1517-25. [PMID: 15834125 DOI: 10.1194/jlr.m500054-jlr200] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We assessed the ability of endothelial lipase (EL) to hydrolyze the sn-1 and sn-2 fatty acids (FAs) from HDL phosphatidylcholine. For this purpose, reconstituted discoidal HDLs (rHDLs) that contained free cholesterol, apolipoprotein A-I, and either 1-palmitoyl-2-oleoylphosphatidylcholine, 1-palmitoyl-2-linoleoylphosphatidylcholine, or 1-palmitoyl-2-arachidonylphosphatidylcholine were incubated with EL- and control (LacZ)-conditioned media. Gas chromatography analysis of the reaction mixtures revealed that both the sn-1 (16:0) and sn-2 (18:1, 18:2, and 20:4) FAs were liberated by EL. The higher rate of sn-1 FA cleavage compared with sn-2 FA release generated corresponding sn-2 acyl lyso-species as determined by MS analysis. EL failed to release sn-2 FA from rHDLs containing 1-O-1'-hexadecenyl-2-arachidonoylphosphatidylcholine, whose sn-1 position contained a nonhydrolyzable alkyl ether linkage. The lack of phospholipase A(2) activity of EL and its ability to liberate [(14)C]FA from [(14)C]lysophosphatidylcholine (lyso-PC) led us to conclude that EL-mediated deacylation of phosphatidylcholine (PC) is initiated at the sn-1 position, followed by the release of the remaining FA from the lyso-PC intermediate. Thin-layer chromatography analysis of cellular lipids obtained from EL-overexpressing cells revealed a pronounced accumulation of [(14)C]phospholipid and [(14)C]triglyceride upon incubation with 1-palmitoyl-2-[1-(14)C]linoleoyl-PC-labeled HDL(3), indicating the ability of EL to supply cells with unsaturated FAs.
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Affiliation(s)
- M Gauster
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University Graz, Harrachgasse 21/III, Graz A-8010, Austria
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Ishida T, Choi SY, Kundu RK, Spin J, Yamashita T, Hirata KI, Kojima Y, Yokoyama M, Cooper AD, Quertermous T. Endothelial Lipase Modulates Susceptibility to Atherosclerosis in Apolipoprotein-E-deficient Mice. J Biol Chem 2004; 279:45085-92. [PMID: 15304490 DOI: 10.1074/jbc.m406360200] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Endothelial lipase (EL) expression correlates inversely with circulating high density lipoprotein (HDL) cholesterol levels in genetic mouse models, and human genetic variation in this locus has been linked to differences in HDL cholesterol levels. These data suggest a role for EL in the development of atherosclerotic vascular disease. To investigate this possibility, LIPG-null alleles were bred onto the apoE knockout background, and the homozygous double knockout animals were characterized. Both apoE knockout and double knockout mice had low HDL cholesterol levels when compared with wild-type mice, but the HDL cholesterol levels of the double knockout mice were higher than those of apoE knockout mice. Atherogenic very low density lipoprotein and intermediate density lipoprotein/low density lipoprotein cholesterol levels of the double knockout mice were also greater than those of the apoE knockout animals. Despite this lipid profile, there was a significant approximately 70% decrease in atherosclerotic disease area in double knockout mice on a regular diet. Immunohistochemistry and protein blot studies revealed increased EL expression in the atherosclerotic aortas of the apoE knockout animals. An observed decrease in macrophage content in vessels lacking EL correlated with ex vivo vascular monocyte adhesion assays, suggesting that this protein can modulate monocyte adhesion and infiltration into diseased tissues. These data suggest that EL may have indirect atherogenic actions in vivo through its effect on circulating HDL cholesterol and direct atherogenic actions through vascular wall processes such as monocyte recruitment and cholesterol uptake.
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Affiliation(s)
- Tatsuro Ishida
- Donald W. Reynolds Cardiovascular Clinical Research Center, Divisions of Cardiovascular Medicine and Gastroenterology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, California 94305, USA
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