1
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Phan A, MacKay JA. Steric stabilization of bioactive nanoparticles using elastin-like polypeptides. Adv Drug Deliv Rev 2024; 206:115189. [PMID: 38281625 DOI: 10.1016/j.addr.2024.115189] [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: 11/28/2023] [Revised: 01/18/2024] [Accepted: 01/22/2024] [Indexed: 01/30/2024]
Abstract
Elastin-like polypeptides (ELP) are versatile, thermo-responsive polymers that can be conjugated to virtually any therapeutic cargo. Derived from short amino-acid sequences and abundant in humans, certain ELPs display low immunogenicity. Substrates for endogenous proteases, ELPs are biodegradable and thus, are candidate biomaterials. Peptides and proteins can be directly coupled with ELPs through genetic engineering, while other polymers and small molecules can be appended through covalent bioconjugation or non-covalent complexation. ELPs that phase separate at physiological temperatures can form the core of nano assemblies; however, ELPs that remain soluble can sterically stabilize the corona of a variety of nanoparticles. Nanoparticles with ELPs at their corona promote colloids with favorable pharmacokinetic (PK) properties that enables therapeutic efficacy with intermittent administration. This review highlights a comprehensive spectrum of ELP fusions shown to stabilize the solubility, and sometimes bioactivity, of their cargo - with a focus on biophysical properties that underlie their therapeutic effects.
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Affiliation(s)
- Alvin Phan
- Department of Pharmacology and Pharmaceutical Sciences, Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - J Andrew MacKay
- Department of Pharmacology and Pharmaceutical Sciences, Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA 90089, USA; Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, CA 90089, USA; Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA.
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2
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White CR, Palgunachari M, Wolkowicz P, Anantharamaiah GM. Peptides as Therapeutic Agents for Atherosclerosis. Methods Mol Biol 2022; 2419:89-110. [PMID: 35237960 DOI: 10.1007/978-1-0716-1924-7_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
More than three decades ago, as a test for the amphipathic helix theory, an 18 amino acid residue peptide and its analogs were designed with no sequence homology to any of the exchangeable apolipoproteins. Based on the apolipoprotein A-I (the major protein component of high density lipoproteins, HDL) mimicking properties, they were termed as ApoA-I mimicking peptides. Several laboratories around the world started studying such de novo-designed peptides for their antiatherogenic properties. The present chapter describes the efforts in bringing these peptides as therapeutic agents for atherosclerosis and several lipid-mediated disorders.
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Affiliation(s)
- C Roger White
- Department of Medicine, UAB Medical Centre, Birmingham, AL, USA
| | | | - Paul Wolkowicz
- Department of Medicine, UAB Medical Centre, Birmingham, AL, USA
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Lee MW, Luo EWC, Silvestre-Roig C, Srinivasan Y, Akabori K, Lemnitzer P, Schmidt NW, Lai GH, Santangelo CD, Soehnlein O, Wong GCL. Apolipoprotein Mimetic Peptide Inhibits Neutrophil-Driven Inflammatory Damage via Membrane Remodeling and Suppression of Cell Lysis. ACS NANO 2021; 15:15930-15939. [PMID: 34586780 PMCID: PMC8720511 DOI: 10.1021/acsnano.1c03978] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Neutrophils are crucial for host defense but are notorious for causing sterile inflammatory damage. Activated neutrophils in inflamed tissue can liberate histone H4, which was recently shown to perpetuate inflammation by permeating membranes via the generation of negative Gaussian curvature (NGC), leading to lytic cell death. Here, we show that it is possible to build peptides or proteins that cancel NGC in membranes and thereby suppress pore formation, and demonstrate that they can inhibit H4 membrane remodeling and thereby reduce histone H4-driven lytic cell death and resultant inflammation. As a demonstration of principle, we use apolipoprotein A-I (apoA-I) mimetic peptide apoMP1. X-ray structural studies and theoretical calculations show that apoMP1 induces nanoscopic positive Gaussian curvature (PGC), which interacts with the NGC induced by the N-terminus of histone H4 (H4n) to inhibit membrane permeation. Interestingly, we show that induction of PGC can inhibit membrane-permeating activity in general and "turn off" diverse membrane-permeating molecules besides H4n. In vitro experiments show an apoMP1 dose-dependent rescue of H4 cytotoxicity. Using a mouse model, we show that tissue accumulation of neutrophils, release of neutrophil extracellular traps (NETs), and extracellular H4 all strongly correlate independently with local tissue cell death in multiple organs, but administration of apoMP1 inhibits histone H4-mediated cytotoxicity and strongly prevents organ tissue damage.
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Affiliation(s)
- Michelle W Lee
- Department of Bioengineering, University of California, Los Angeles, California 90095, United States
| | - Elizabeth Wei-Chia Luo
- Department of Bioengineering, University of California, Los Angeles, California 90095, United States
| | - Carlos Silvestre-Roig
- Institute of Experimental Pathology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, 48149 Münster, Germany
- Institute for Cardiovascular Prevention (IPEK), LMU Munich, 80336 Munich, Germany
| | - Yashes Srinivasan
- Department of Bioengineering, University of California, Los Angeles, California 90095, United States
| | - Kiyotaka Akabori
- Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Patricia Lemnitzer
- Institute of Experimental Pathology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, 48149 Münster, Germany
| | - Nathan W Schmidt
- Department of Bioengineering, University of California, Los Angeles, California 90095, United States
- Ginkgo Bioworks, 27 Drydock Avenue, Boston, Massachusetts 02210, United States
| | - Ghee Hwee Lai
- Department of Bioengineering, University of California, Los Angeles, California 90095, United States
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, 60 Nanyang Drive, SBS-01N-27, Singapore 637551
| | - Christian D Santangelo
- Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, United States
- Department of Physics, Syracuse University, Syracuse, New York 13244, United States
| | - Oliver Soehnlein
- Institute of Experimental Pathology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, 48149 Münster, Germany
- Department of Physiology and Pharmacology (FyFa), Karolinska Institute, 171 77 Stockholm, Sweden
- Institute for Cardiovascular Prevention (IPEK), LMU Munich, 80336 Munich, Germany
| | - Gerard C L Wong
- Department of Bioengineering, University of California, Los Angeles, California 90095, United States
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4
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Delk SC, Chattopadhyay A, Escola-Gil JC, Fogelman AM, Reddy ST. Apolipoprotein mimetics in cancer. Semin Cancer Biol 2020; 73:158-168. [PMID: 33188891 DOI: 10.1016/j.semcancer.2020.11.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 10/10/2020] [Accepted: 11/04/2020] [Indexed: 12/11/2022]
Abstract
Peptides have many advantages over traditional therapeutics, including small molecules and other biologics, because of their low toxicity and immunogenicity, while still exhibiting efficacy. This review discusses the benefits and mechanism of action of apolipoprotein mimetic peptides in tumor biology and their potential utility in treating various cancers. Among lipoproteins in the circulation, high-density lipoprotein (HDL) and its constituents including apolipoprotein A-I (apoA-I; the predominant protein in HDL), apoJ, and apoE, harbor anti-tumorigenic activities. Peptides that mimic apoA-I function have been developed through molecular mimicry of the amphipathic α-helices of apoA-I. Oral apoA-I mimetic peptides remodel HDL, promote cholesterol efflux, sequester oxidized lipids, and activate anti-inflammatory processes. ApoA-I and apoJ mimetic peptides ameliorate various metrics of cancer progression and have demonstrated efficacy in preclinical models in the inhibition of ovarian, colon, breast, and metastatic lung cancers. Apolipoprotein mimetic peptides are poorly absorbed when administered orally and rapidly degraded when injected into the circulation. The small intestine is the major site of action for apoA-I mimetic peptides and recent studies suggest that modulation of immune cells in the lamina propria of the small intestine is, in part, a potential mechanism of action. Finally, several recent studies underscore the use of reconstituted HDL as target-specific nanoparticles carrying poorly soluble or unstable therapeutics to tumors even across the blood-brain barrier. Preclinical studies suggest that these versatile recombinant lipoprotein based nanoparticles and apolipoprotein mimetics can serve as safe, novel drug delivery, and therapeutic agents for the treatment of a number of cancers.
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Affiliation(s)
- Samuel C Delk
- Molecular Toxicology Interdepartmental Degree Program, Fielding School of Public Health, University of California, Los Angeles, CA, 90095, USA; Department of Medicine, Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095, USA
| | - Arnab Chattopadhyay
- Department of Medicine, Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095, USA
| | - Joan Carles Escola-Gil
- Institut d'Investigacions Biomèdiques (IIB) Sant Pau, Sant Quintí 77, 08041, Barcelona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Monforte de Lemos 3-5, 28029, Madrid, Spain; Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Antoni M. Claret 167, 08025, Barcelona, Spain
| | - Alan M Fogelman
- Department of Medicine, Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095, USA
| | - Srinivasa T Reddy
- Molecular Toxicology Interdepartmental Degree Program, Fielding School of Public Health, University of California, Los Angeles, CA, 90095, USA; Department of Medicine, Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095, USA; Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095, USA; Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095, USA.
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5
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Acidic extracellular pH promotes accumulation of free cholesterol in human monocyte-derived macrophages via inhibition of ACAT1 activity. Atherosclerosis 2020; 312:1-7. [PMID: 32942042 DOI: 10.1016/j.atherosclerosis.2020.08.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 08/14/2020] [Accepted: 08/27/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND AIMS In focal areas of advanced human atherosclerotic lesions, the intimal fluid is acidic. An acidic medium impairs the ABCA1-mediated cholesterol efflux from macrophages, so tending to increase their content of free cholesterol, which is then available for esterification by the macrophage enzyme ACAT1. Here we investigated whether low extracellular pH would affect the activity of ACAT1. METHODS - Human monocyte-derived macrophages were first incubated with acetyl-LDL at neutral and acidic conditions (pH 7.5, 6.5, and 5.5) to generate foam cells, and then the foam cells were incubated with [3H]oleate-BSA complexes, and the formation of [3H]oleate-labeled cholesteryl esters was measured. ACAT1 activity was also measured in cell-free macrophage extracts. RESULTS - In acidic media, ACAT1-dependent cholesteryl [3H]oleate generation became compromised in the developing foam cells and their content of free cholesterol increased. In line with this finding, ACAT1 activity in the soluble cell-free fraction derived from macrophage foam cells peaked at pH 7, and gradually decreased under acidic pH with a rapid drop below pH 6.5. Incubation of macrophages under progressively more acidic conditions (until pH 5.5) lowered the cytosolic pH of macrophages (down to pH 6.0). Such intracellular acidification did not affect macrophage gene expression of ACAT1 or the neutral CEH. CONCLUSIONS Exposure of human macrophage foam cells to acidic conditions lowers their intracellular pH with simultaneous decrease in ACAT1 activity. This reduces cholesterol esterification and thus leads to accumulation of potentially toxic levels of free cholesterol, a contributing factor to macrophage foam cell death.
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Pownall HJ, Gotto AM. Cholesterol: Can't Live With It, Can't Live Without It. Methodist Debakey Cardiovasc J 2019; 15:9-15. [PMID: 31049144 DOI: 10.14797/mdcj-15-1-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Given its role in many biochemical processes essential to life, cholesterol remains a topic of intense research. Of all the plasma lipids, cholesterol is distinctive because it is a precursor to steroidogenic molecules, some of which regulate metabolism, and its blood concentration in the form of low- and high-density lipoprotein cholesterol (HDL-C) are positive and negative risk factors for atherosclerotic cardiovascular disease (ASCVD). New research, however, has challenged the widely held belief that high HDL-C levels are atheroprotective and is showing that both low and high plasma HDL-C levels confer an increased risk of ASCVD. Furthermore, it is disputing the widely cited mechanism involved in reverse cholesterol transport. This review explores the evolution of cholesterol research starting with the Gofman and Framingham studies, the development of traditional and emerging lipid-lowering therapies, and the role of reverse cholesterol transport in HDL cardioprotection.
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Affiliation(s)
- Henry J Pownall
- HOUSTON METHODIST RESEARCH INSTITUTE, HOUSTON, TEXAS; WEILL CORNELL MEDICINE, NEW YORK, NEW YORK
| | - Antonio M Gotto
- HOUSTON METHODIST RESEARCH INSTITUTE, HOUSTON, TEXAS; WEILL CORNELL MEDICINE, NEW YORK, NEW YORK
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7
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Tsujita M, Wolska A, Gutmann DAP, Remaley AT. Reconstituted Discoidal High-Density Lipoproteins: Bioinspired Nanodiscs with Many Unexpected Applications. Curr Atheroscler Rep 2018; 20:59. [PMID: 30397748 DOI: 10.1007/s11883-018-0759-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
PURPOSE OF REVIEW Summarize the initial discovery of discoidal high-density lipoprotein (HDL) in human plasma and review more recent innovations that span the use of reconstituted nanodisc HDL for membrane protein characterization to its use as a drug carrier and a novel therapeutic agent for cardiovascular disease. RECENT FINDINGS Using a wide variety of biophysical techniques, the structure and composition of endogenous discoidal HDL have now largely been solved. This has led to the development of new methods for the in vitro reconstitution of nanodisc HDL, which have proven to have a wide variety of biomedical applications. Nanodisc HDL has been used as a platform for mimicking the plasma membrane for the reconstitution and investigation of the structures of several plasma membrane proteins, such as cytochrome P450s and ABC transporters. Nanodisc HDL has also been designed as drug carriers to transport amphipathic, as well as hydrophobic small molecules, and has potential therapeutic applications for several diseases. Finally, nanodisc HDL itself like native discoidal HDL can mediate cholesterol efflux from cells and are currently being tested in late-stage clinical trials for cardiovascular disease. The discovery of the characterization of native discoidal HDL has inspired a new field of synthetic nanodisc HDL, which has offered a growing number of unanticipated biomedical applications.
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Affiliation(s)
- Maki Tsujita
- Department of Biochemistry, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan.
| | - Anna Wolska
- Lipoprotein Metabolism Laboratory, Translational Vascular Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | | | - Alan T Remaley
- Lipoprotein Metabolism Laboratory, Translational Vascular Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
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8
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Abstract
Releasing sterols to the extracellular milieu is an important part of sterol homeostasis in cells and in the body. ATP-binding cassette transporter A1 (ABCA1) plays an essential role in cellular phospholipid and sterol release to lipid-free or lipid-poor apolipoprotein A-I (apoA-I), the major apolipoprotein in high-density lipoprotein (HDL), and constitutes the first step in the formation of nascent HDL. Loss-of-function mutations in the ABCA1 gene lead to a rare disease known as Tangier disease that causes severe deficiency in plasma HDL level. Mammalian cells receive exogenous cholesterol mainly from low-density lipoprotein. In addition, they synthesize cholesterol endogenously, as well as multiple precursor sterols that are sterol intermediates en route to be converted to cholesterol. HDL contains phospholipids, cholesterol, and precursor sterols, and ABCA1 has an ability to release phospholipids and various sterol molecules. Recent studies using model cell lines showed that ABCA1 prefers to use sterols newly synthesized endogenously as its preferred substrate, rather than cholesterol derived from LDL or cholesterol being recycled within the cells. Here, we describe several methods at the cell culture level to monitor ABCA1-dependent release of sterol molecules to apoA-I present at the cell exterior. Sterol release can be assessed by using a simple colorimetric enzymatic assay, and/or by monitoring the radioactivities of radiolabeled cholesterol incorporated into the cells, and/or of sterols biosynthesized from radioactive acetate, and/or by using gas chromatography-mass spectrometry analysis of various sterols present in medium and in cells. We also discuss the pros and cons of these methods. Together, these methods allow researchers to detect the release not only of cholesterol but also of other sterols present in minor quantities.
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Affiliation(s)
- Yoshio Yamauchi
- Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan. .,Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
| | - Shinji Yokoyama
- Nutritional Health Science Research Center, and Department of Food and Nutritional Sciences, Chubu University, 1200 Matsumotocho, Kasugai, 487-8501, Japan
| | - Ta-Yuan Chang
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, 7200 Vail Bldg. Room 304, Hanover, NH, 03755, USA.
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9
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Swertfeger DK, Li H, Rebholz S, Zhu X, Shah AS, Davidson WS, Lu LJ. Mapping Atheroprotective Functions and Related Proteins/Lipoproteins in Size Fractionated Human Plasma. Mol Cell Proteomics 2017; 16:680-693. [PMID: 28223350 DOI: 10.1074/mcp.m116.066290] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 02/13/2017] [Indexed: 11/06/2022] Open
Abstract
HDL has been shown to possess a variety of cardio-protective functions, including removal of excess cholesterol from the periphery, and inhibition of lipoprotein oxidation. It has been proposed that various HDL subparticles exist, each with distinct protein and lipid compositions, which may be responsible for HDL's many functions. We hypothesized that HDL functions will co-migrate with the operational lipoprotein subspecies when separated by gel filtration chromatography. Plasma from 10 healthy male donors was fractionated and the protein composition of the phospholipid containing fractions was analyzed by mass spectrometry (MS). Each fraction was evaluated for its proteomic content as well as its ability to promote cholesterol efflux and protect low density lipoprotein (LDL) from free radical oxidation. For each function, several peaks of activity were identified across the plasma size gradient. Neither cholesterol efflux or LDL antioxidation activity correlated strongly with any single protein across the fractions. However, we identified multiple proteins that had strong correlations (r values >0.7, p < 0.01) with individual peaks of activity. These proteins fell into diverse functional categories, including those traditionally associated with lipid metabolism, as well as alternative complement cascade, innate immunity and clotting cascades and immunoglobulins. Additionally, the phospholipid and cholesterol concentration of the fractions correlated strongly with cholesterol efflux (r = 0.95 and 0.82 respectively), whereas the total protein content of the fractions correlated best with antioxidant activity across all fractions (r = 0.746). Furthermore, two previously postulated subspecies (apoA-I, apoA-II and apoC-1; as well as apoA-I, apoC-I and apoJ) were found to have strong correlations with both cholesterol efflux and antioxidation activity. Up till now, very little has been known about how lipoprotein composition mediates functions like cholesterol efflux and antioxidation.
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Affiliation(s)
- Debi K Swertfeger
- §Division of Biomedical Informatics, Cincinnati Children's Hospital Research Foundation, 3333 Burnet Avenue, Cincinnati, Ohio 45229-3039
| | - Hailong Li
- §Division of Biomedical Informatics, Cincinnati Children's Hospital Research Foundation, 3333 Burnet Avenue, Cincinnati, Ohio 45229-3039
| | - Sandra Rebholz
- §Division of Biomedical Informatics, Cincinnati Children's Hospital Research Foundation, 3333 Burnet Avenue, Cincinnati, Ohio 45229-3039.,¶Center for Lipid and Arteriosclerosis Science, Department of Pathology and Laboratory Medicine, University of Cincinnati, 2120 East Galbraith Road, Cincinnati, Ohio 45237-0507
| | - Xiaoting Zhu
- §Division of Biomedical Informatics, Cincinnati Children's Hospital Research Foundation, 3333 Burnet Avenue, Cincinnati, Ohio 45229-3039
| | - Amy S Shah
- ‖Division of Endocrinology, Cincinnati Children's Hospital Research Foundation, 3333 Burnet Avenue, Cincinnati, Ohio 45229-3039
| | - W Sean Davidson
- ¶Center for Lipid and Arteriosclerosis Science, Department of Pathology and Laboratory Medicine, University of Cincinnati, 2120 East Galbraith Road, Cincinnati, Ohio 45237-0507
| | - Long J Lu
- From the ‡School of Information Management, Wuhan University, Wuhan 430072, China; .,§Division of Biomedical Informatics, Cincinnati Children's Hospital Research Foundation, 3333 Burnet Avenue, Cincinnati, Ohio 45229-3039
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10
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Cao YN, Xu L, Han YC, Wang YN, Liu G, Qi R. Recombinant high-density lipoproteins and their use in cardiovascular diseases. Drug Discov Today 2016; 22:180-185. [PMID: 27591840 DOI: 10.1016/j.drudis.2016.08.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 08/24/2016] [Accepted: 08/25/2016] [Indexed: 10/21/2022]
Abstract
The unique anti-atherosclerosis abilities and other cardioprotective properties make high-density lipoprotein (HDL) a promising solution in treating cardiovascular diseases. A number of studies showed that HDL-based therapy was well tolerated and has great potential in the future. Among all these new agents, the most studied ones including recombinant HDL, recombinant human apolipoproteins, apolipoprotein mimetic peptides and recombinant HDL used as contrast agents in cardiovascular imaging are discussed here. Recombinant HDL and apolipoproteins are promising in diagnosing and treating cardiovascular diseases.
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Affiliation(s)
- Yi-Ni Cao
- Peking University Institute of Cardiovascular Sciences, Peking University Health Science Center, 38 Xueyuan Road, Beijing 100191, China; Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, China
| | - Lu Xu
- Peking University Institute of Cardiovascular Sciences, Peking University Health Science Center, 38 Xueyuan Road, Beijing 100191, China; Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, China
| | - Ying-Chun Han
- Peking University Institute of Cardiovascular Sciences, Peking University Health Science Center, 38 Xueyuan Road, Beijing 100191, China; Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, China
| | - Yu-Nan Wang
- Peking University Institute of Cardiovascular Sciences, Peking University Health Science Center, 38 Xueyuan Road, Beijing 100191, China; Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, China
| | - George Liu
- Peking University Institute of Cardiovascular Sciences, Peking University Health Science Center, 38 Xueyuan Road, Beijing 100191, China; Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, China
| | - Rong Qi
- Peking University Institute of Cardiovascular Sciences, Peking University Health Science Center, 38 Xueyuan Road, Beijing 100191, China; Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, China.
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11
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Gulshan K, Brubaker G, Conger H, Wang S, Zhang R, Hazen SL, Smith JD. PI(4,5)P2 Is Translocated by ABCA1 to the Cell Surface Where It Mediates Apolipoprotein A1 Binding and Nascent HDL Assembly. Circ Res 2016; 119:827-38. [PMID: 27514935 DOI: 10.1161/circresaha.116.308856] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 08/11/2016] [Indexed: 12/23/2022]
Abstract
RATIONALE The molecular mechanism by which ATP-binding cassette transporter A1 (ABCA1) mediates cellular binding of apolipoprotein A-I (apoA1) and nascent high-density lipoprotein (HDL) assembly is not well understood. OBJECTIVE To determine the cell surface lipid that mediates apoA1 binding to ABCA1-expressing cells and the role it plays in nascent HDL assembly. METHODS AND RESULTS Using multiple biochemical and biophysical methods, we found that apoA1 binds specifically to phosphatidylinositol (4,5) bis-phosphate (PIP2). Flow cytometry and PIP2 reporter-binding assays demonstrated that ABCA1 led to PIP2 redistribution from the inner to the outer leaflet of the plasma membrane. Enzymatic cleavage of cell surface PIP2 or decreased cellular PIP2 by knockdown of phosphatidylinositol-5-phosphate 4-kinase impaired apoA1 binding and cholesterol efflux to apoA1. PIP2 also increased the spontaneous solubilization of phospholipid liposomes by apoA1. Using site-directed mutagenesis, we found that ABCA1's PIP2 and phosphatidylserine translocase activities are independent from each other. Furthermore, we discovered that PIP2 is effluxed from cells to apoA1, where it is associated with HDL in plasma, and that PIP2 on HDL is taken up by target cells in a scavenger receptor-BI-dependent manner. Mouse plasma PIP2 levels are apoA1 gene dosage-dependent and are >1 μM in apoA1 transgenic mice. CONCLUSIONS ABCA1 has PIP2 floppase activity, which increases cell surface PIP2 levels that mediate apoA1 binding and lipid efflux during nascent HDL assembly. We found that PIP2 itself is effluxed to apoA1 and it circulates on plasma HDL, where it can be taken up via the HDL receptor scavenger receptor-BI.
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Affiliation(s)
- Kailash Gulshan
- From the Department of Cellular and Molecular Medicine (K.G., G.B., H.C., S.W., R.Z., S.L.H., J.D.S.) and Department of Cardiovascular Medicine (S.L.H., J.D.S.), Cleveland Clinic, OH.
| | - Gregory Brubaker
- From the Department of Cellular and Molecular Medicine (K.G., G.B., H.C., S.W., R.Z., S.L.H., J.D.S.) and Department of Cardiovascular Medicine (S.L.H., J.D.S.), Cleveland Clinic, OH
| | - Heather Conger
- From the Department of Cellular and Molecular Medicine (K.G., G.B., H.C., S.W., R.Z., S.L.H., J.D.S.) and Department of Cardiovascular Medicine (S.L.H., J.D.S.), Cleveland Clinic, OH
| | - Shuhui Wang
- From the Department of Cellular and Molecular Medicine (K.G., G.B., H.C., S.W., R.Z., S.L.H., J.D.S.) and Department of Cardiovascular Medicine (S.L.H., J.D.S.), Cleveland Clinic, OH
| | - Renliang Zhang
- From the Department of Cellular and Molecular Medicine (K.G., G.B., H.C., S.W., R.Z., S.L.H., J.D.S.) and Department of Cardiovascular Medicine (S.L.H., J.D.S.), Cleveland Clinic, OH
| | - Stanley L Hazen
- From the Department of Cellular and Molecular Medicine (K.G., G.B., H.C., S.W., R.Z., S.L.H., J.D.S.) and Department of Cardiovascular Medicine (S.L.H., J.D.S.), Cleveland Clinic, OH
| | - Jonathan D Smith
- From the Department of Cellular and Molecular Medicine (K.G., G.B., H.C., S.W., R.Z., S.L.H., J.D.S.) and Department of Cardiovascular Medicine (S.L.H., J.D.S.), Cleveland Clinic, OH.
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12
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Abstract
The concept of lipoprotein mimetics was developed and extensively tested in the last three decades. Most lipoprotein mimetics were designed to recreate one or several functions of high-density lipoprotein (HDL) in the context of cardiovascular disease; however, the application of this approach is much broader. Lipoprotein mimetics should not just be seen as a set of compounds aimed at replenishing a deficiency or dysfunctionality of individual elements of lipoprotein metabolism but rather as a designer concept with remarkable flexibility and numerous applications in medicine and biology. In the present review, we discuss the fundamental design principles used to create lipoprotein mimetics, mechanisms of their action, medical indications and efficacy in animal models and human studies.
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13
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Tang C, Houston BA, Storey C, LeBoeuf RC. Both STAT3 activation and cholesterol efflux contribute to the anti-inflammatory effect of apoA-I/ABCA1 interaction in macrophages. J Lipid Res 2016; 57:848-57. [PMID: 26989082 DOI: 10.1194/jlr.m065797] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Indexed: 12/13/2022] Open
Abstract
ABCA1 exports excess cholesterol from cells to apoA-I and is essential for HDL synthesis. Genetic studies have shown that ABCA1 protects against cardiovascular disease. We have previously shown that the interaction of apoA-I with ABCA1 activates signaling molecule Janus kinase 2 (JAK2), which optimizes the cholesterol efflux activity of ABCA1. ABCA1-mediated activation of JAK2 also activates signal transducer and activator of transcription 3 (STAT3), which significantly attenuates proinflammatory cytokine expression in macrophages. To determine the mechanisms of the anti-inflammatory effects of apoA-I/ABCA1 interaction, we identified two special ABCA1 mutants, one with normal STAT3-activating capacity but lacking cholesterol efflux ability and the other with normal cholesterol efflux ability but lacking STAT3-activating capacity. We showed that activation of STAT3 by the interaction of apoA-I/ABCA1 without cholesterol efflux could significantly decrease proinflammatory cytokine expression in macrophages. Mechanistic studies showed that the anti-inflammatory effect of the apoA-I/ABCA1/STAT3 pathway is suppressor of cytokine signaling 3 dependent. Moreover, we showed that apoA-I/ABCA1-mediated cholesterol efflux without STAT3 activation can also reduce proinflammatory cytokine expression in macrophages. These findings suggest that the interaction of apoA-I/ABCA1 activates cholesterol efflux and STAT3 branch pathways to synergistically suppress inflammation in macrophages.
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Affiliation(s)
- Chongren Tang
- Division of Metabolism, Endocrinology and Nutrition, Diabetes Obesity Center for Excellence, University of Washington, Seattle, WA 98109
| | - Barbara A Houston
- Division of Metabolism, Endocrinology and Nutrition, Diabetes Obesity Center for Excellence, University of Washington, Seattle, WA 98109
| | - Carl Storey
- Division of Metabolism, Endocrinology and Nutrition, Diabetes Obesity Center for Excellence, University of Washington, Seattle, WA 98109
| | - Renee C LeBoeuf
- Division of Metabolism, Endocrinology and Nutrition, Diabetes Obesity Center for Excellence, University of Washington, Seattle, WA 98109
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14
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Zamanian-Daryoush M, DiDonato JA. Apolipoprotein A-I and Cancer. Front Pharmacol 2015; 6:265. [PMID: 26617517 PMCID: PMC4642354 DOI: 10.3389/fphar.2015.00265] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 10/23/2015] [Indexed: 12/22/2022] Open
Abstract
High-density lipoprotein (HDL) and apolipoprotein A-I (apoA-I), the predominant protein in plasma HDL, have long been the focus of intense studies in the field of atherosclerosis and cardiovascular disease. ApoA-I, in large part, is responsible for HDL assembly and its main atheroprotective function, that of shuttling excess cholesterol from peripheral tissues to the liver for excretion (reverse cholesterol transport). Recently, a protective role for HDL in cancer was suggested from several large clinical studies where an inverse relationship between plasma HDL-cholesterol (HDL-C) levels and risk of developing cancer was noted. This notion has now been tested and found to be supported in mouse tumor studies, where increasing levels of apoA-I/HDL were discovered to protect against tumor development and provision of human apoA-I was therapeutic against established tumors. This mini-review discusses the emerging role of apoA-I in tumor biology and its potential as cancer therapeutic.
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Affiliation(s)
- Maryam Zamanian-Daryoush
- Department of Cellular and Molecular Medicine, and Center for Cardiovascular Diagnostics and Prevention, Cleveland Clinic, Cleveland OH, USA
| | - Joseph A DiDonato
- Department of Cellular and Molecular Medicine, and Center for Cardiovascular Diagnostics and Prevention, Cleveland Clinic, Cleveland OH, USA
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15
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Pownall HJ, Rosales C, Gillard BK, Gotto AM. High-Density Lipoprotein Therapies-Then and Now. Atherosclerosis 2015. [DOI: 10.1002/9781118828533.ch42] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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16
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White CR, Garber DW, Anantharamaiah GM. Anti-inflammatory and cholesterol-reducing properties of apolipoprotein mimetics: a review. J Lipid Res 2014; 55:2007-21. [PMID: 25157031 DOI: 10.1194/jlr.r051367] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Reduced levels of HDL cholesterol (HDL-C) are a strong independent predictor of coronary artery disease (CAD) risk. The major anti-atherogenic function of HDL is to mediate reverse cholesterol transport. This response is highly dependent on apoA-I and apoE, protein components of HDL. Randomized clinical trials have assessed effects of several classes of drugs on plasma cholesterol levels in CAD patients. Agents including cholestyramine, fibrates, niacin, and statins significantly lower LDL cholesterol (LDL-C) and induce modest increases in HDL-C, but tolerance issues and undesirable side effects are common. Additionally, residual risk may be present in patients with persistently low HDL-C and other complications despite a reduction in LDL-C. These observations have fueled interest in the development of new pharmacotherapies that positively impact circulating lipoproteins. The goal of this review is to discuss the therapeutic potential of synthetic apolipoprotein mimetic peptides. These include apoA-I mimetic peptides that have undergone initial clinical assessment. We also discuss newer apoE mimetics that mediate the clearance of atherogenic lipids from the circulation and possess anti-inflammatory properties. One of these (AEM-28) has recently been given orphan drug status and is undergoing clinical trials.
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Affiliation(s)
- C Roger White
- Department of Medicine, Divisions of Cardiovascular Disease, Gerontology, Geriatric Medicine University of Alabama at Birmingham, Birmingham, AL
| | - David W Garber
- Palliative Care, University of Alabama at Birmingham, Birmingham, AL
| | - G M Anantharamaiah
- Palliative Care, University of Alabama at Birmingham, Birmingham, AL Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL
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17
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Pastuszka MK, Wang X, Lock LL, Janib SM, Cui H, DeLeve LD, MacKay JA. An amphipathic alpha-helical peptide from apolipoprotein A1 stabilizes protein polymer vesicles. J Control Release 2014; 191:15-23. [PMID: 25016969 DOI: 10.1016/j.jconrel.2014.07.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 07/03/2014] [Accepted: 07/03/2014] [Indexed: 01/04/2023]
Abstract
L4F, an alpha helical peptide inspired by the lipid-binding domain of the ApoA1 protein, has potential applications in the reduction of inflammation involved with cardiovascular disease as well as an antioxidant effect that inhibits liver fibrosis. In addition to its biological activity, amphipathic peptides such as L4F are likely candidates to direct the molecular assembly of peptide nanostructures. Here we describe the stabilization of the amphipathic L4F peptide through fusion to a high molecular weight protein polymer. Comprised of multiple pentameric repeats, elastin-like polypeptides (ELPs) are biodegradable protein polymers inspired from the human gene for tropoelastin. Dynamic light scattering confirmed that the fusion peptide forms nanoparticles with a hydrodynamic radius of approximately 50nm, which is unexpectedly above that observed for the free ELP (~5.1nm). To further investigate their morphology, conventional and cryogenic transmission electron microscopy were used to reveal that they are unilamellar vesicles. On average, these vesicles are 49nm in radius with lamellae 8nm in thickness. To evaluate their therapeutic potential, the L4F nanoparticles were incubated with hepatic stellate cells. Stellate cell activation leads to hepatic fibrosis; furthermore, their activation is suppressed by anti-oxidant activity of ApoA1 mimetic peptides. Consistent with this observation, L4F nanoparticles were found to suppress hepatic stellate cell activation in vitro. To evaluate the in vivo potential for these nanostructures, their plasma pharmacokinetics were evaluated in rats. Despite the assembly of nanostructures, both free L4F and L4F nanoparticles exhibited similar half-lives of approximately 1h in plasma. This is the first study reporting the stabilization of peptide-based vesicles using ApoA1 mimetic peptides fused to a protein polymer; furthermore, this platform for peptide-vesicle assembly may have utility in the design of biodegradable nanostructures.
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Affiliation(s)
- Martha K Pastuszka
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA 90033-9121, USA
| | - Xiangdong Wang
- Research Center for Liver Diseases and the Division of Gastrointestinal and Liver Diseases, Keck School of Medicine at the University of Southern California, Los Angeles, CA 90033, USA
| | - Lye Lin Lock
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Siti Mohd Janib
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA 90033-9121, USA
| | - Honggang Cui
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Laurie D DeLeve
- Research Center for Liver Diseases and the Division of Gastrointestinal and Liver Diseases, Keck School of Medicine at the University of Southern California, Los Angeles, CA 90033, USA
| | - J Andrew MacKay
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA 90033-9121, USA; Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA.
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18
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Aluganti Narasimhulu C, Selvarajan K, Brown M, Parthasarathy S. Cationic peptides neutralize Ox-LDL, prevent its uptake by macrophages, and attenuate inflammatory response. Atherosclerosis 2014; 236:133-41. [PMID: 25036240 DOI: 10.1016/j.atherosclerosis.2014.06.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 06/11/2014] [Accepted: 06/19/2014] [Indexed: 01/27/2023]
Abstract
OBJECTIVE Apolipoprotein A1 (ApoA1) and apolipoprotein E (ApoE) mimetic peptides have attracted attention due to their ability to reduce atherosclerosis and exhibit antioxidant, anti-inflammatory, and hypolipidemic properties. In this study, we tested whether three distinct and unrelated cationic peptides would inhibit the oxidation of lipoproteins and whether they would counteract and neutralize the negatively charged modified lipoproteins, inhibit their uptake and inflammation by macrophages. METHODS AND RESULTS 5F-mimetic peptide of ApoA1, LL27 derived from the anti-microbial peptide hCAP, and a human glycodelin derived peptide were commercially synthesized. We noted that these three distinct cationic lysine-rich peptides, two of which were unrelated to any known apolipoproteins, inhibited copper-mediated oxidation of lipoproteins and reduced lipid peroxides in a lysine dependent manner. The peptides also retarded the electrophoretic mobility of previously oxidized LDL and acetylated LDL by virtue of their net positive charge. Pre-incubation of peptides with modified lipoproteins reduced the uptake of the latter by macrophages, thus preventing the formation of foam cells. The cationic peptides inhibited oxidized LDL (Ox-LDL)-induced inflammatory response both in vitro and in vivo. CONCLUSION Based on these results, we suggest that in addition to the well known mimetic peptides, other suitable cationic peptides may be of use for controlling Ox-LDL mediated inflammation and atherosclerotic progression.
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Affiliation(s)
| | - Krithika Selvarajan
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32827, USA
| | - Matthew Brown
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32827, USA
| | - Sampath Parthasarathy
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32827, USA.
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19
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Abstract
PURPOSE OF REVIEW To review recent advances in our understanding of the mechanism of action of apoprotein A-I (apoA-I) mimetic peptides and improved methods for the oral delivery of peptides. RECENT FINDINGS The apoA-I mimetic peptides are based on the structure of the major apoprotein of HDL with the expectation that they may also mimic some of the antiatherogenic functions of HDL. Recent work has provided insight into mechanisms by which they may be antioxidative and anti-inflammatory. In addition, recent work has shifted the focus of the site of action of the mimetic peptides to the small intestine from the plasma and HDL and suggests modulation of bioactive oxidized lipids in the intestine by the peptides may be a major antiatherogenic pathway. The development of transgenic tomatoes expressing an apoA-I mimetic peptide is a significant advance in the oral delivery of peptides as therapies for cardiovascular disease and other chronic inflammatory disorders. SUMMARY In the past year, there have been important advances in the field of apoA-I mimetic peptides, including the oral delivery of bioactive peptides. Further work is required to fully understand the molecular basis for the effect of the peptide on the intestine and bioactive oxidized lipids.
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Affiliation(s)
- Godfrey S Getz
- The University of Chicago, Department of Pathology, Chicago, Illinois, USA
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20
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Modulation of adipose tissue lipolysis and body weight by high-density lipoproteins in mice. Nutr Diabetes 2014; 4:e108. [PMID: 24567123 PMCID: PMC3940828 DOI: 10.1038/nutd.2014.4] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 01/05/2014] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Obesity is associated with reduced levels of circulating high-density lipoproteins (HDLs) and its major protein, apolipoprotein (apo) A-I. As a result of the role of HDL and apoA-I in cellular lipid transport, low HDL and apoA-I may contribute directly to establishing or maintaining the obese condition. METHODS To test this, male C57BL/6 wild-type (WT), apoA-I deficient (apoA-I(-/-)) and apoA-I transgenic (apoA-I(tg/tg)) mice were fed obesogenic diets (ODs) and monitored for several clinical parameters. We also performed cell culture studies. RESULTS ApoA-I(-/-) mice gained significantly more body weight and body fat than WT mice over 20 weeks despite their reduced food intake. During a caloric restriction regime imposed on OD-fed mice, apoA-I deficiency significantly inhibited the loss of body fat as compared with WT mice. Reduced body fat loss with caloric restriction in apoA-I(-/-) mice was associated with blunted stimulated adipose tissue lipolysis as verified by decreased levels of phosphorylated hormone-sensitive lipase (p-HSL) and lipolytic enzyme mRNA. In contrast to apoA-I(-/-) mice, apoA-I(tg/tg) mice gained relatively less weight than WT mice, consistent with other reports. ApoA-I(tg/tg) mice showed increased adipose tissue lipolysis, verified by increased levels of p-HSL and lipolytic enzyme mRNA. In cell culture studies, HDL and apoA-I specifically increased catecholamine-induced lipolysis possibly through modulating the adipocyte plasma membrane cholesterol content. CONCLUSIONS Thus, apoA-I and HDL contribute to modulating body fat content by controlling the extent of lipolysis. ApoA-I and HDL are key components of lipid metabolism in adipose tissue and constitute new therapeutic targets in obesity.
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21
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Sharifov OF, Nayyar G, Ternovoy VV, Palgunachari MN, Garber DW, Anantharamaiah G, Gupta H. Comparison of anti-endotoxin activity of apoE and apoA mimetic derivatives of a model amphipathic peptide 18A. Innate Immun 2013; 20:867-80. [PMID: 24323453 DOI: 10.1177/1753425913514621] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Endotoxemia is a major cause of chronic inflammation, and is an important pathogenic factor in the development of metabolic syndrome and atherosclerosis. Human apolipoprotein E (apoE) and apoA-I are protein components of high-density lipoprotein, which have strong anti-endotoxin activity. Here, we compared anti-endotoxin activity of Ac-hE18A-NH2 and 4F peptides, modified from model amphipathic helical 18A peptide, to mimic, respectively, apoE and apoA-I properties. Ac-hE18A-NH2, stronger than 4F, inhibited endotoxin activity and disaggregated Escherichia coli 055:B5 (wild smooth serotype). Ac-hE18A-NH2 and 4F inhibited endotoxin activity of E. coli 026:B6 (rough-like serotype) to a similar degree. This suggests that Ac-hE18A-NH2 as a dual-domain molecule might interact with both the lipid A and headgroup of smooth LPS, whereas 4F binds lipid A. In C57BL/6 mice, Ac-hE18A-NH2 was superior to 4F in inhibiting the inflammatory responses mediated by E. coli 055:B5, but not E. coli 026:B6. However, in THP-1 cells, isolated human primary leukocytes, and whole human blood, Ac-hE18A-NH2 reduced responses more strongly than 4F to both E. coli serotypes either when peptides were pre-incubated or co-incubated with LPS, indicating that Ac-hE18A-NH2 also has strong anti-inflammatory effects independent of endotoxin-neutralizing properties. In conclusion, Ac-hE18A-NH2 is more effective than 4F in inhibiting LPS-mediated inflammation, which opens prospective clinical applications for Ac-hE18A-NH2.
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Affiliation(s)
- Oleg F Sharifov
- Department of Medicine, University of Alabama at Birmingham, AL, USA
| | - Gaurav Nayyar
- Department of Medicine, University of Alabama at Birmingham, AL, USA
| | | | | | - David W Garber
- Department of Medicine, University of Alabama at Birmingham, AL, USA
| | - Gm Anantharamaiah
- Department of Medicine, University of Alabama at Birmingham, AL, USA Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, AL, USA
| | - Himanshu Gupta
- Department of Medicine, University of Alabama at Birmingham, AL, USA VA Medical Center, Birmingham, AL, USA
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22
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Leman LJ, Maryanoff BE, Ghadiri MR. Molecules that mimic apolipoprotein A-I: potential agents for treating atherosclerosis. J Med Chem 2013; 57:2169-96. [PMID: 24168751 DOI: 10.1021/jm4005847] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Certain amphipathic α-helical peptides can functionally mimic many of the properties of full-length apolipoproteins, thereby offering an approach to modulate high-density lipoprotein (HDL) for combating atherosclerosis. In this Perspective, we summarize the key findings and advances over the past 25 years in the development of peptides that mimic apolipoproteins, especially apolipoprotein A-I (apoA-I). This assemblage of information provides a reasonably clear picture of the state of the art in the apolipoprotein mimetic field, an appreciation of the potential for such agents in pharmacotherapy, and a sense of the opportunities for optimizing the functional properties of HDL.
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Affiliation(s)
- Luke J Leman
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute , 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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23
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Pownall HJ, Gillard BK, Gotto AM. Setting the course for apoAII: a port in sight? ACTA ACUST UNITED AC 2013; 8:551-560. [PMID: 25067958 DOI: 10.2217/clp.13.59] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
ApoAII, the second most abundant protein of the human plasma HDLs, was discovered nearly 50 years ago. Over the subsequent years, nearly 2000 studies - epidemiological, cell-based, biochemical, mouse and human - have attempted to unravel its role in human lipid metabolism. On the basis of these studies, apoAII has been described as an activator and inhibitor of various plasma activities, and as both pro- and anti-atherogenic. Here, we summarize the studies of apoAII, use the preponderance of evidence to propose that the apoAII compass can be reset towards an antiatherogenic course, and suggest ways to stay the course.
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Affiliation(s)
- Henry J Pownall
- Houston Methodist Research Institute, 6670 Bertner Avenue, Houston, TX 77030, USA
| | - Baiba K Gillard
- Houston Methodist Research Institute, 6670 Bertner Avenue, Houston, TX 77030, USA
| | - Antonio M Gotto
- Houston Methodist Research Institute, 6670 Bertner Avenue, Houston, TX 77030, USA
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24
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Vaisar T. Proteomics investigations of HDL: challenges and promise. Curr Vasc Pharmacol 2012; 10:410-21. [PMID: 22339300 DOI: 10.2174/157016112800812755] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 09/01/2011] [Accepted: 11/06/2011] [Indexed: 02/02/2023]
Abstract
High density lipoprotein (HDL) is recognized as the major negative risk factor of cardiovascular disease and number of anti-atherogenic functions has been ascribed to HDL. HDL is an assembly of a neutral lipid core and an outer shell consisting of polar lipids and proteins. It has been defined many different ways based on various distinct properties including density flotation, protein composition, molecular size, and electrophoretic migration. Overall the studies characterizing HDL clearly demonstrate that it is a complex heterogeneous mixture of particles. Furthermore several studies convincingly demonstrated that certain populations of HDL particles have a distinct functionality suggesting that HDL may serve as a platform for assembly of protein complexes with very specific biological functions. Indeed recent proteomics studies described over 100 proteins associated with HDL. Here we review approaches to isolation and proteomic analysis of HDL and discuss potential problems associated with isolation methods which may confound our understanding of the relation of the HDL composition and its biological function.
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Affiliation(s)
- Tomáš Vaisar
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, 815 Mercer St, Seattle, WA 98109, USA.
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25
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26
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ApoA-1 mimetic restores adiponectin expression and insulin sensitivity independent of changes in body weight in female obese mice. Nutr Diabetes 2012; 2:e33. [PMID: 23169576 PMCID: PMC3341710 DOI: 10.1038/nutd.2012.4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND We examined the ability of the apolipoprotein AI mimetic peptide L-4F to improve the metabolic state of female and male ob mice and the mechanisms involved. METHODS Female and male lean and obese (ob) mice were administered L-4F or vehicle for 6 weeks. Body weight was measured weekly. Fat distribution, serum cytokines and markers of cardiovascular dysfunction were determined at the end of treatment. RESULTS L-4F significantly decreased serum interleukin (IL)-6, tumor necrosis factor-α and IL-1β. L-4F improved vascular function, and increased serum adiponectin levels and insulin sensitivity compared with untreated mice. In addition, L-4F treatment increased heme oxygenase (HO)-1, pAKT and pAMPK levels in kidneys of ob animals. pAKT and pAMPK levels were significantly reduced in the presence of an HO inhibitor. Interestingly, L4F did not alter body weight in female mice, but caused a significant reduction in males. CONCLUSIONS L-4F treatments reduced cardiovascular risk factors and improved insulin sensitivity in female ob mice independent of body fat changes. Reduced inflammatory cytokine levels accompanied by increased HO activity, serum adiponectin and improved insulin sensitivity suggest that L-4F may promote the conversion of visceral fat to a healthier phenotype. Therefore, L-4F appears to be a promising therapeutic strategy for treating both cardiovascular risk factors and insulin resistance in obese patients of either gender.
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27
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Shao B. Site-specific oxidation of apolipoprotein A-I impairs cholesterol export by ABCA1, a key cardioprotective function of HDL. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:490-501. [PMID: 22178192 DOI: 10.1016/j.bbalip.2011.11.011] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 11/18/2011] [Accepted: 11/20/2011] [Indexed: 12/11/2022]
Abstract
The mechanisms that deprive HDL of its cardioprotective properties are poorly understood. One potential pathway involves oxidative damage of HDL proteins by myeloperoxidase (MPO) a heme enzyme secreted by human artery wall macrophages. Mass spectrometric analysis demonstrated that levels of 3-chlorotyrosine and 3-nitrotyrosine - two characteristic products of MPO - are elevated in HDL isolated from patients with established cardiovascular disease. When apolipoprotein A-I (apoA-I), the major HDL protein, is oxidized by MPO, its ability to promote cellular cholesterol efflux by the membrane-associated ATP-binding cassette transporter A1 (ABCA1) pathway is diminished. Biochemical studies revealed that oxidation of specific tyrosine and methionine residues in apoA-I contributes to this loss of ABCA1 activity. Another potential mechanism for generating dysfunctional HDL involves covalent modification of apoA-I by reactive carbonyls, which have been implicated in atherogenesis and diabetic vascular disease. Indeed, modification of apoA-I by malondialdehyde (MDA) or acrolein also markedly impaired the lipoprotein's ability to promote cellular cholesterol efflux by the ABCA1 pathway. Tandem mass spectrometric analyses revealed that these reactive carbonyls target specific Lys residues in the C-terminus of apoA-I. Importantly, immunochemical analyses showed that levels of MDA-protein adducts are elevated in HDL isolated from human atherosclerotic lesions. Also, apoA-I co-localized with acrolein adducts in such lesions. Thus, lipid peroxidation products might specifically modify HDL in vivo. Our observations support the hypotheses that MPO and reactive carbonyls might generate dysfunctional HDL in humans. This article is part of a Special Issue entitled Advances in High Density Lipoprotein Formation and Metabolism: A Tribute to John F. Oram (1945-2010).
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Affiliation(s)
- Baohai Shao
- Division of Metabolism, Endocrinology and Nutrition, Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, WA 98109, USA.
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28
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Liu Y, Tang C. Regulation of ABCA1 functions by signaling pathways. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:522-9. [PMID: 21920460 DOI: 10.1016/j.bbalip.2011.08.015] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 08/02/2011] [Accepted: 08/20/2011] [Indexed: 10/17/2022]
Abstract
ATP-binding cassette transporter A1 (ABCA1) is an integral cell membrane protein that protects cardiovascular disease by at least two mechanisms: by export of excess cholesterol from cells and by suppression of inflammation. ABCA1 exports cholesterol and phospholipids from cells by multiple steps that involve forming cell surface lipid domains, binding of apolipoproteins to ABCA1, activating signaling pathways, and solubilizing these lipids by apolipoproteins. ABCA1 executes its anti-inflammatory effect by modifying cell membrane lipid rafts and directly activating signaling pathways. The interaction of apolipoproteins with ABCA1 activates multiple signaling pathways, including Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3), protein kinase A, Rho family G protein CDC42 and protein kinase C. Activating protein kinase A and Rho family G protein CDC42 regulates ABCA1-mediated lipid efflux, activating PKC stabilizes ABCA1 protein, and activating JAK2/STAT3 regulates both ABCA1-mediated lipid efflux and anti-inflammation. Thus, ABCA1 behaves both as a lipid exporter and a signaling receptor. Targeting ABCA1 receptor-like property using agonists for ABCA1 protein could become a promising new therapeutic target for increasing ABCA1 function and treating cardiovascular disease. This article is part of a Special Issue entitled Advances in High Density Lipoprotein Formation and Metabolism: A Tribute to John F. Oram (1945-2010).
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Affiliation(s)
- Yuhua Liu
- Deparment of Medicine, Diabetes and Obesity Center of Excellence, University of Washington, Seattle, WA 98195-8055, USA
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29
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Sviridov DO, Ikpot IZ, Stonik J, Drake SK, Amar M, Osei-Hwedieh DO, Piszczek G, Turner S, Remaley AT. Helix stabilization of amphipathic peptides by hydrocarbon stapling increases cholesterol efflux by the ABCA1 transporter. Biochem Biophys Res Commun 2011; 410:446-51. [PMID: 21672528 DOI: 10.1016/j.bbrc.2011.05.154] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 05/27/2011] [Indexed: 10/18/2022]
Abstract
Apolipoprotein mimetic peptides are short amphipathic peptides that efflux cholesterol from cells by the ABCA1 transporter and are being investigated as therapeutic agents for cardiovascular disease. We examined the role of helix stabilization of these peptides in cholesterol efflux. A 23-amino acid long peptide (Ac-VLEDSFKVSFLSALEEYTKKLNTQ-NH2) based on the last helix of apoA-I (A10) was synthesized, as well as two variants, S1A10 and S2A10, in which the third and fourth and third and fifth turn of each peptide, respectively, were covalently joined by hydrocarbon staples. By CD spectroscopy, the stapled variants at 24 °C were more helical in aqueous buffer than A10 (A10 17%, S1A10 62%, S2A10 97%). S1A10 and S2A10 unlike A10 were resistant to proteolysis by pepsin and chymotrypsin. S1A10 and S2A10 showed more than a 10-fold increase in cholesterol efflux by the ABCA1 transporter compared to A10. In summary, hydrocarbon stapling of amphipathic peptides increases their helicity, makes them resistant to proteolysis and enhances their ability to promote cholesterol efflux by the ABCA1 transporter, indicating that this peptide modification may be useful in the development of apolipoprotein mimetic peptides.
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Affiliation(s)
- D O Sviridov
- Lipoprotein Metabolism Section, Cardiopulmonary Branch, NHLBI, National Institutes of Health, Bethesda, MD 20892-1508, USA
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Shao B, Heinecke JW. Impact of HDL oxidation by the myeloperoxidase system on sterol efflux by the ABCA1 pathway. J Proteomics 2011; 74:2289-99. [PMID: 21501700 DOI: 10.1016/j.jprot.2011.04.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 03/30/2011] [Accepted: 04/02/2011] [Indexed: 12/15/2022]
Abstract
Protein oxidation by phagocytic white blood cells is implicated in tissue injury during inflammation. One important target might be high-density lipoprotein (HDL), which protects against atherosclerosis by removing excess cholesterol from artery wall macrophages. In the human artery wall, cholesterol-laden macrophages are a rich source of myeloperoxidase (MPO), which uses hydrogen peroxide for oxidative reactions in the extracellular milieu. Levels of two characteristic products of MPO-chlorotyrosine and nitrotyrosine-are markedly elevated in HDL from human atherosclerotic lesions. Here, we describe how MPO-dependent chlorination impairs the ability of apolipoprotein A-I (apoA-I), HDL's major protein, to transport cholesterol by the ATP-binding cassette transporter A1 (ABCA1) pathway. Faulty interactions between apoA-I and ABCA1 are involved. Tandem mass spectrometry and investigations of mutated forms of apoA-I demonstrate that tyrosine residues in apoA-I are chlorinated in a site-specific manner by chloramine intermediates on suitably juxtaposed lysine residues. Plasma HDL isolated from subjects with coronary artery disease (CAD) also contains higher levels of chlorinated and nitrated tyrosine residues than HDL from healthy subjects. Thus, the presence of chlorinated HDL might serve as a marker of CAD risk. Because HDL damaged by MPO in vitro becomes dysfunctional, inhibiting MPO in vivo might be cardioprotective.
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Affiliation(s)
- Baohai Shao
- Division of Metabolism, Endocrinology and Nutrition, Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, WA 98109, USA.
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Getz GS, Wool GD, Reardon CA. HDL apolipoprotein-related peptides in the treatment of atherosclerosis and other inflammatory disorders. Curr Pharm Des 2011; 16:3173-84. [PMID: 20687877 DOI: 10.2174/138161210793292492] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Accepted: 07/21/2010] [Indexed: 12/31/2022]
Abstract
Elevations of HDL levels or modifying the inflammatory properties of HDL are being evaluated as possible treatment of atherosclerosis, the underlying mechanism responsible for most cardiovascular diseases. A promising approach is the use of small HDL apoprotein-related mimetic peptides. A number of peptides mimicking the repeating amphipathic α-helical structure in apoA-I, the major apoprotein in HDL, have been examined in vitro and in animal models. Several peptides have been shown to reduce early atherosclerotic lesions, but not more mature lesions unless coadministered with statins. These peptides also influence the vascular biology of the vessel wall and protect against other acute and chronic inflammatory diseases. The biologically active peptides are capable of reducing the pro-inflammatory properties of LDL and HDL, likely due to their high affinity for oxidized lipids. They are also capable of influencing other processes, including ABCA1 mediated activation of JAK-2 in macrophages, which may contribute to their anti-atherogenic function. The initial studies involved monomeric 18 amino acid peptides, but tandem peptides are being investigated for their anti-atherogenic and anti-inflammatory properties as they more closely resemble the repeating structure of apoA-I. Peptides based on other HDL associated proteins such as apoE, apoJ and SAA have also been studied. Their mechanism of action appears to be distinct from the apoA-I based mimetics.
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Affiliation(s)
- G S Getz
- The University of Chicago, Department of Pathology, 5841 S. Maryland Avenue, Chicago, IL 60637, USA.
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Osei-Hwedieh DO, Amar M, Sviridov D, Remaley AT. Apolipoprotein mimetic peptides: Mechanisms of action as anti-atherogenic agents. Pharmacol Ther 2010; 130:83-91. [PMID: 21172387 DOI: 10.1016/j.pharmthera.2010.12.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Accepted: 12/01/2010] [Indexed: 12/13/2022]
Abstract
Apolipoprotein mimetic peptides are short synthetic peptides that share structural, as well as biological features of native apolipoproteins. The early positive clinical trials of intravenous preparations of apoA-I, the main protein component of high density lipoproteins (HDL), have stimulated great interest in the use of apolipoprotein mimetic peptides as possible therapeutic agents. Currently, there are a wide variety of apolipoprotein mimetic peptides at various stages of drug development. These peptides typically have been designed to either promote cholesterol efflux or act as anti-oxidants, but they usually exert other biological effects, such as anti-inflammatory and anti-thrombotic effects. Uncertainty about which of these biological properties is the most important for explaining their anti-atherogenic effect is a major unresolved question in the field. Structure-function studies relating the in vitro properties of these peptides to their ability to reduce atherosclerosis in animal models may uncover the best rationale for the design of these peptides and may lead to a better understanding of the mechanisms behind the atheroprotective effect of HDL.
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Affiliation(s)
- David O Osei-Hwedieh
- Lipoprotein Metabolism Section, Cardio-pulmonary Branch, NHLBI, National Institutes of Health, Bethesda, MD, USA
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Abstract
PURPOSE OF REVIEW To review published data related to the potential applicability of apolipoprotein A-I mimetic peptides. RECENT FINDINGS Despite a wealth of information on HDL-C levels and risk for cardiovascular disease (CVD), little evidence is present to suggest that raising HDL-C levels per se will result in CVD risk reduction. Rather, increasing HDL functionality might be a more successful strategy to reverse the process of atherosclerosis. In as such, apoA-I mimetic peptides, either in single or tandem formulation, hold great promise. Evidence gathered over the last years has provided insight in the extent to which mimetics influence several cardio metabolic pathways. ApoA-I mimetics have shown to have anti-inflammatory, antioxidant, and antiatherogenic effects. Direct comparisons between different mimetics have provided insight in factors influencing the differential beneficial consequences of these peptides. Data derived from recent studies suggest that mimetics might gain their position as a therapeutic intervention in the treatment of septicaemia, transplantation rejection, diabetes and auto-immune diseases. SUMMARY This review provides a summary of the current literature on the potential application of apoA-I mimetics as therapeutic agents. There is increasing evidence that these mimetics should be considered as a promising supplement to current strategies. Results from human studies addressing the in-vivo effects of the different apoA-I mimetics are eagerly awaited.
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Affiliation(s)
- G K Hovingh
- Department Vascular Medicine, Academic Medical Center, Meibergdreef 9 F4-159.2, 1100DD Amsterdam, The Netherlands.
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Abstract
Apolipoprotein A-I (apoA-I) mimetic peptides resemble the physiochemical properties of the helices of apoA-I and show promise for the treatment of atherosclerotic vascular diseases and other chronic inflammatory disorders. These peptides have numerous properties, such as the ability to remodel high-density lipoprotein, sequester oxidized lipids, promote cholesterol efflux, and activate an anti-inflammatory process in macrophages, any or all of which may contribute to their antiatherogenic properties. In murine models, the 4F peptide attenuates early atherosclerosis but seems to require the addition of statins to influence more mature lesions. A recently developed method for the oral delivery of the peptides that protects them from proteolysis will facilitate further research on the mechanism of action of these peptides. This review focuses on the properties of the 4F peptide, although numerous apoA-I mimetics are under investigation and a single "best" peptide that mimics all of the properties of the antiatherogenic protein apoA-I has not been identified.
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Handattu SP, Datta G, Epand RM, Epand RF, Palgunachari MN, Mishra VK, Monroe CE, Keenum TD, Chaddha M, Anantharamaiah GM, Garber DW. Oral administration of L-mR18L, a single domain cationic amphipathic helical peptide, inhibits lesion formation in ApoE null mice. J Lipid Res 2010; 51:3491-9. [PMID: 20841495 DOI: 10.1194/jlr.m006916] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
We have shown that Ac-hE18A-NH₂, a dual-domain cationic apolipoprotein-mimetic peptide, reduces plasma cholesterol levels in dyslipidemic mice. Two single-domain cationic peptides based on the lytic class L peptide 18L were developed to test the hypothesis that a single-domain cationic amphipathic peptide can reduce atherosclerosis in apolipoprotein (apo)E null mice when orally administered. To incorporate anti-inflammatory properties, aromatic residues were clustered in the nonpolar face similar to peptide 4F, resulting in modified 18L (m18L). To reduce lytic properties, the Lys residues of 18L were replaced with Arg with the resulting peptide called modified R18L (mR18L). Biophysical studies showed that mR18L had stronger interactions with lipids than did m18L. Peptide mR18L was also more effective than m18L in promoting LDL uptake by HepG2 cells. ApoE null mice received normal chow or chow containing m18L or mR18L for six weeks. A significant reduction in plasma cholesterol and aortic sinus lesion area was seen only in the mR18L group. Plasma from mice administered mR18L, unlike those from the control and m18L groups, did not enhance monocyte adhesion to endothelial cells. Thus oral administration of mR18L reduces plasma cholesterol and lesion formation and inhibits monocyte adhesion.
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Affiliation(s)
- Shaila P Handattu
- Atherosclerosis Research Unit, Department of Medicine, University of Alabama, Birmingham, AL, USA
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D'Souza W, Stonik JA, Murphy A, Demosky SJ, Sethi AA, Moore XL, Chin-Dusting J, Remaley AT, Sviridov D. Structure/function relationships of apolipoprotein a-I mimetic peptides: implications for antiatherogenic activities of high-density lipoprotein. Circ Res 2010; 107:217-27. [PMID: 20508181 DOI: 10.1161/circresaha.110.216507] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Apolipoprotein (apoA)-I mimetic peptides are a promising type of anti-atherosclerosis therapy, but how the structural features of these peptides relate to the multiple antiatherogenic functions of HDL is poorly understood. OBJECTIVE To establish structure/function relationships of apoA-I mimetic peptides with their antiatherogenic functions. METHODS AND RESULTS Twenty-two bihelical apoA-I mimetic peptides were investigated in vitro for the capacity and specificity of cholesterol efflux, inhibition of inflammatory response of monocytes and endothelial cells, and inhibition of low-density lipoprotein (LDL) oxidation. It was found that mean hydrophobicity, charge, size of hydrophobic face, and angle of the link between the helices are the major factors determining the efficiency and specificity of cholesterol efflux. The peptide with optimal parameters was more effective and specific toward cholesterol efflux than human apoA-I. Charge and size of hydrophobic face were also the major factors affecting antiinflammatory properties, and the presence of cysteine and histidine residues was the main factor determining antioxidant properties. There was no significant correlation between capacities of the peptides to support individual functions; each function had its own optimal set of features. CONCLUSIONS None of the peptides was equally effective in all the antiatherogenic functions tested, suggesting that different functions of HDL may have different mechanisms and different structural requirements. The results do suggest, however, that rationalizing the design of apoA-I mimetic peptides may improve their therapeutic value and may lead to a better understanding of mechanisms of various antiatherogenic functions of HDL.
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Affiliation(s)
- Wilissa D'Souza
- Baker Heart and Diabetes Institute, PO Box 6492, St Kilda Rd, Melbourne 8008, Australia
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Abstract
PURPOSE OF REVIEW Synthetic high-density lipoprotein (HDL) and apolipoprotein (apo) A-I mimetic peptides emulate many of the atheroprotective biological functions attributed to HDL and can modify atherosclerotic disease processes. Administration of these agents as HDL replacement or modifying therapy has tremendous potential of providing new treatments for cardiovascular disease. Progress in the understanding of these agents is discussed in this review. RECENT FINDINGS Prospective, observational, and interventional studies have convincingly demonstrated that elevated serum levels of high-density lipoprotein-cholesterol (HDL-C) are associated with reduced risk for coronary heart disease (CHD). Although traditional pharmacological agents have shown modest utility in raising HDL levels and reducing CHD risk, use of HDL and apo A-I mimetics provides novel therapies to not only increase HDL levels, but to also influence HDL functionality. Evidence developed over the last several years has identified a number of pathways affected by synthetic HDL and apoA-I mimetic peptides, including enhancing reverse cholesterol transport and reducing oxidation and inflammation that directly influence the progression and regression of atherosclerotic disease. SUMMARY Clinical trials of relatively short-term synthetic HDL infusion into patients with CHD demonstrate beneficial effects. Use of apo A-I mimetic peptides could potentially overcome some of the limitations associated with use of the intact apo. Studies to establish the most efficacious peptides, optimal dosing regimens, and routes of administration are needed. Use of apo A-I mimetic peptides shows great promise as a therapeutic modality for HDL replacement and enhancing HDL function in treatment of patients with CHD.
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Affiliation(s)
- Armando J Mendez
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Diabetes Research Institute, Miller School of Medicine, University of Miami, Miami, Florida 33136, USA.
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Tang C, Kanter JE, Bornfeldt KE, Leboeuf RC, Oram JF. Diabetes reduces the cholesterol exporter ABCA1 in mouse macrophages and kidneys. J Lipid Res 2009; 51:1719-28. [PMID: 19965614 DOI: 10.1194/jlr.m003525] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Accumulation of cholesterol in arterial macrophages may contribute to diabetes-accelerated atherosclerotic cardiovascular disease. The ATP-binding cassette transporter ABCA1 is a cardioprotective membrane protein that mediates cholesterol export from macrophages. Factors elevated in diabetes, such as reactive carbonyls and free fatty acids, destabilize ABCA1 protein in cultured macrophages, raising the possibility that impaired ABCA1 plays an atherogenic role in diabetes. We therefore examined the modulation of ABCA1 in two mouse models of diabetes. We isolated peritoneal macrophages, livers, kidneys, and brains from type 1 non-obese diabetic (NOD) mice and mice made diabetic by viral-induced autoimmune destruction of pancreatic beta-cells, and we measured ABCA1 protein and mRNA levels and cholesterol contents. ABCA1 protein levels and cholesterol export activity were reduced by 40-44% (P<0.01) in peritoneal macrophages and protein levels by 48% (P<0.001) in kidneys in diabetic NOD mice compared with nondiabetic animals, even though ABCA1 mRNA levels were not significantly different. A similar selective reduction in ABCA1 protein was found in peritoneal macrophages (33%, P<0.05) and kidneys (35%, P<0.05) from the viral-induced diabetic mice. In liver and brain, however, diabetes had no effect or slightly increased ABCA1 protein and mRNA levels. The reduced ABCA1 in macrophages and kidneys was associated with increased cholesterol content. Impaired ABCA1-mediated cholesterol export could therefore contribute to the increased atherosclerosis and nephropathy associated with diabetes.
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Affiliation(s)
- Chongren Tang
- Department of Medicine, University of Washington, Seattle, WA 98195, USA.
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Tang C, Liu Y, Kessler PS, Vaughan AM, Oram JF. The macrophage cholesterol exporter ABCA1 functions as an anti-inflammatory receptor. J Biol Chem 2009; 284:32336-43. [PMID: 19783654 DOI: 10.1074/jbc.m109.047472] [Citation(s) in RCA: 218] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
ATP-binding cassette transporter A1 (ABCA1) is a cell membrane protein that exports excess cholesterol from cells to apolipoprotein (apo) A-I, the major protein in high density lipoproteins. Genetic studies have shown that ABCA1 protects against cardiovascular disease. The interaction of apoA-I with ABCA1 promotes cholesterol removal and activates signaling molecules, such as Janus kinase 2 (JAK2), that optimize the lipid export activity of ABCA1. Here we show that the ABCA1-mediated activation of JAK2 also activates STAT3, which is independent of the lipid transport function of ABCA1. ABCA1 contains two candidate STAT3 docking sites that are required for the apoA-I/ABCA1/JAK2 activation of STAT3. The interaction of apoA-I with ABCA1-expressing macrophages suppressed the ability of lysopolysaccaride to induce the inflammatory cytokines interleukin-1beta, interleukin-6, and tumor necrosis factor-alpha, which was reversed by silencing STAT3 or ABCA1. Thus, the apoA-I/ABCA1 pathway in macrophages functions as an anti-inflammatory receptor through activation of JAK2/STAT3. These findings implicate ABCA1 as a direct molecular link between the cardioprotective effects of cholesterol export from arterial macrophages and suppressed inflammation.
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Affiliation(s)
- Chongren Tang
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, Washington 98195, USA
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41
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Minagawa H, Gong JS, Jung CG, Watanabe A, Lund-Katz S, Phillips MC, Saito H, Michikawa M. Mechanism underlying apolipoprotein E (ApoE) isoform-dependent lipid efflux from neural cells in culture. J Neurosci Res 2009; 87:2498-508. [PMID: 19326444 PMCID: PMC3065888 DOI: 10.1002/jnr.22073] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We determined the molecular mechanisms underlying apolipoprotein E (ApoE)-isoform-dependent lipid efflux from neurons and ApoE-deficient astrocytes in culture. The ability of ApoE3 to induce lipid efflux was 2.5- to 3.9-fold greater than ApoE4. To explore the contributions of the amino- and carboxyl-terminal tertiary structure domains of ApoE to cellular lipid efflux, each domain was studied separately. The amino-terminal fragment of ApoE3 (22-kDa-ApoE3) induced lipid efflux greater than 22-kDa-ApoE4, whereas the common carboxyl-terminal fragment of ApoE induced very low levels of lipid efflux. Addition of segments of the carboxyl-terminal domain to 22-kDa-ApoE3 additively induced lipid efflux in a length-dependent manner; in contrast, this effect did not occur with ApoE4. This observation, coupled with the fact that introduction of the E255A mutation (which disrupts domain-domain interaction) into ApoE4 increases lipid efflux, indicates that interaction between the amino- and carboxyl-terminal domains in ApoE4 reduces the ability of this isoform to mediate lipid efflux from neural cells. Dimeric 22-kDa or intact ApoE3 induced higher lipid efflux than monomeric 22-kDa or intact ApoE3, respectively, indicating that dimerization of ApoE3 enhances the ability to release lipids. The adenosine triphosphate-binding cassette protein A1 (ABCA1) is involved in ApoE-induced lipid efflux. In conclusion, there are two major factors, intramolecular domain interaction and intermolecular dimerization, that cause ApoE-isoform-dependent lipid efflux from neural cells in culture.
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Affiliation(s)
- Hirohisa Minagawa
- Department of Alzheimer’s Disease Research, National Institute for Longevity Sciences, National Center for Geriatrics and Gerontology, Aichi, Japan
| | - Jiang-Sheng Gong
- Department of Alzheimer’s Disease Research, National Institute for Longevity Sciences, National Center for Geriatrics and Gerontology, Aichi, Japan
| | - Cha-Gyun Jung
- Department of Alzheimer’s Disease Research, National Institute for Longevity Sciences, National Center for Geriatrics and Gerontology, Aichi, Japan
| | - Atsushi Watanabe
- Department of Vascular Dementia, National Institute for Longevity Sciences, National Center for Geriatrics and Gerontology, Aichi, Japan
| | - Sissel Lund-Katz
- Lipid Research Group, Children’s Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Michael C. Phillips
- Lipid Research Group, Children’s Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Hiroyuki Saito
- Department of Biophysical Chemistry, Kobe Pharmaceutical University, Kobe, Japan
| | - Makoto Michikawa
- Department of Alzheimer’s Disease Research, National Institute for Longevity Sciences, National Center for Geriatrics and Gerontology, Aichi, Japan
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Getz GS, Wool GD, Reardon CA. Apoprotein A-I mimetic peptides and their potential anti-atherogenic mechanisms of action. Curr Opin Lipidol 2009; 20:171-5. [PMID: 19373084 DOI: 10.1097/mol.0b013e32832ac051] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE OF REVIEW Peptides that resemble in physicochemical properties the helices of apoprotein A-I, the major protein of atheroprotective HDL, show promise for the treatment of atherosclerosis-related vascular disease. The properties and promise of these so-called mimetic peptides will be explored in this review. RECENT FINDINGS Both HDL and mimetic peptides are able to scavenge and sequester oxidized lipids and hence protect endothelial cells and arteries from the pro-inflammatory action of oxidized LDL. Active mimetic peptides have an amphipathic alpha-helical secondary structure, whose hydrophobic face is particularly important for its bioactivity. The most frequently employed peptide is 4F. The comparative bioactivity of variants of 4F, particularly tandem helical peptides, has been explored. The recent observation of the very high affinity of bioactive peptides for oxidized fatty acids and phospholipids provides a likely mechanism for the action of these peptides in inhibiting early atherosclerosis formation. It is not clear that these peptides alone are effective in reversing established atherosclerosis, although they may achieve this outcome in synergy with statin therapy. SUMMARY Recent observations of mimetic peptides have pointed to promising therapies for patients with cardiovascular disease. The peptides appear to be well tolerated and effective in promoting the anti-inflammatory properties of HDL.
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Affiliation(s)
- Godfrey S Getz
- Department of Pathology, The University of Chicago, Chicago, Illinois 60637, USA.
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White CR, Datta G, Mochon P, Zhang Z, Kelly O, Curcio C, Parks D, Palgunachari M, Handattu S, Gupta H, Garber DW, Anantharamaiah GM. Vasculoprotective Effects of Apolipoprotein Mimetic Peptides: An Evolving Paradigm In Hdl Therapy (Vascular Disease Prevention, In Press.). ACTA ACUST UNITED AC 2009; 6:122-130. [PMID: 20084185 DOI: 10.2174/1567270000906010122] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Anti-atherogenic effects of high density lipoprotein (HDL) and its major protein component apolipoprotein A-I (apoA-I) are principally thought to be due to their ability to mediate reverse cholesterol transport. These agents also possess anti-oxidant properties that prevent the oxidative modification of low density lipoprotein (LDL) and anti-inflammatory properties that include inhibition of endothelial cell adhesion molecule expression. Results of the Framingham study revealed that a reduction in HDL levels is an independent risk factor for coronary artery disease (CAD). Accordingly, there has been considerable interest in developing new therapies that specifically elevate HDL cholesterol. However, recent evidence suggests that increasing circulating HDL cholesterol levels alone is not sufficient as a mode of HDL therapy. Rather, therapeutic approaches that increase the functional properties of HDL may be superior to simply raising the levels of HDL per se. Our laboratory has pioneered the development of synthetic, apolipoprotein mimetic peptides which are structurally and functionally similar to apoA-I but possess unique structural homology to the lipid-associating domains of apoA-I. The apoA-I mimetic peptide 4F inhibits atherogenic lesion formation in murine models of atherosclerosis. This effect is related to the ability of 4F to induce the formation of pre-β HDL particles that are enriched in apoA-I and paraoxonase. 4F also possesses anti-inflammatory and anti-oxidant properties that are independent of its effect on HDL quality per se. Recent studies suggest that 4F stimulates the expression of the antioxidant enzymes heme oxygenase and superoxide dismutase and inhibits superoxide anion formation in blood vessels of diabetic, hypercholesterolemic and sickle cell disease mice. The goal of this review is to discuss HDL-dependent and -independent mechanisms by which apoA-I mimetic peptides reduce vascular injury in experimental animal models.
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Affiliation(s)
- C Roger White
- Department of Medicine, Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL
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Tang C, Oram JF. The cell cholesterol exporter ABCA1 as a protector from cardiovascular disease and diabetes. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:563-72. [PMID: 19344785 DOI: 10.1016/j.bbalip.2009.03.011] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Revised: 03/17/2009] [Accepted: 03/17/2009] [Indexed: 01/28/2023]
Abstract
ATP-binding cassette transporter A1 (ABCA1) is an integral cell membrane protein that exports cholesterol from cells and suppresses macrophage inflammation. ABCA1 exports cholesterol by a multistep pathway that involves forming cell-surface lipid domains, solubilizing these lipids by apolipoproteins, binding of apolipoproteins to ABCA1, and activating signaling processes. Thus, ABCA1 behaves both as a lipid exporter and a signaling receptor. ABCA1 transcription is highly induced by sterols, and its expression and activity are regulated post-transcriptionally by diverse processes. ABCA1 mutations can reduce plasma HDL levels, accelerate cardiovascular disease, and increase the risk for type 2 diabetes. Genetic manipulations of ABCA1 expression in mice also affect plasma HDL levels, inflammation, atherogenesis, and pancreatic beta cell function. Metabolites elevated in individuals with the metabolic syndrome and diabetes destabilize ABCA1 protein and decrease cholesterol export from macrophages, raising the possibility that an impaired ABCA1 pathway contributes to the enhanced atherogenesis associated with common inflammatory and metabolic disorders. The ABCA1 pathway has therefore become a promising new therapeutic target for treating cardiovascular disease and diabetes.
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Affiliation(s)
- Chongren Tang
- Department of Medicine, University of Washington, Seattle, Washington 98195-8055, USA.
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45
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White CR, Datta G, Zhang Z, Gupta H, Garber DW, Mishra VK, Palgunachari MN, Handattu SP, Chaddha M, Anantharamaiah GM. HDL therapy for cardiovascular diseases: the road to HDL mimetics. Curr Atheroscler Rep 2008; 10:405-12. [PMID: 18706282 DOI: 10.1007/s11883-008-0063-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) are currently the drug of choice for the clinical management of elevated low-density lipoprotein (LDL) cholesterol. Although statin treatment provides an overall improvement in outcomes, clinical trial data reveal a significant number of cardiac events despite reaching targeted LDL levels. A low serum high-density lipoprotein (HDL) cholesterol level is an independent predictor of cardiovascular risk. Accordingly, there has been interest in determining whether HDL elevation, in addition to LDL lowering, further reduces risk in patients with coronary artery disease. Several commonly prescribed lipid-lowering therapies modestly raise HDL, but their use may be limited by the development of adverse reactions. Emerging data suggest that HDL quality and function may also be significantly reduced by atherosclerosis and other inflammatory diseases. The goal of this review is to discuss the current status of HDL therapeutics, with emphasis on a novel class of agent, the apolipoprotein A-I mimetic peptides, which improve the functional properties of HDL cholesterol.
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Affiliation(s)
- C Roger White
- Vascular Biology and Hypertension Program, University of Alabama, Birmingham, 1046 Zeigler Research Building, 703 South 19th Street, Birmingham, AL 35294, USA.
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Van Lenten BJ, Navab M, Anantharamaiah GM, Buga GM, Reddy ST, Fogelman AM. Multiple indications for anti-inflammatory apolipoprotein mimetic peptides. CURRENT OPINION IN INVESTIGATIONAL DRUGS (LONDON, ENGLAND : 2000) 2008; 9:1157-1162. [PMID: 18951294 PMCID: PMC2856620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Apolipoprotein mimetic peptides dramatically reduce atherosclerosis in animal models, and may be an excellent mode of therapy to treat a variety of vascular inflammatory conditions, including atherosclerosis. Studies of apolipoprotein mimetic peptides in models of inflammatory disorders other than atherosclerosis, including viral influenza, asthma, chronic rejection after heart transplantation, sickle cell disease, scleroderma, diabetes, cognitive dysfunction and renal inflammation, suggest that apolipoprotein mimetic peptides may have efficacy in a wide range of inflammatory conditions.
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Affiliation(s)
- Brian J Van Lenten
- David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-1679, USA.
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Sethi AA, Stonik JA, Thomas F, Demosky SJ, Amar M, Neufeld E, Brewer HB, Davidson WS, D'Souza W, Sviridov D, Remaley AT. Asymmetry in the lipid affinity of bihelical amphipathic peptides. A structural determinant for the specificity of ABCA1-dependent cholesterol efflux by peptides. J Biol Chem 2008; 283:32273-82. [PMID: 18805791 DOI: 10.1074/jbc.m804461200] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ApoA-I contains a tandem array of amphipathic helices with varying lipid affinity, which are critical in its ability to bind and remove lipids from cells by the ABCA1 transporter. In this study, the effect of asymmetry in the lipid affinity of amphipathic helices in a bihelical apoA-I mimetic peptide, 37pA, on lipid efflux by the ABCA1 transporter was examined. Seven peptide variants of 37pA were produced by substituting a varying number of hydrophobic amino acids for alanine on either one or both helices. The 5A peptide with five alanine substitutions in the second helix had decreased helical content compared with 37pA (5A, 12+/-1% helicity; 37pA, 28+/-2% helicity) and showed less self-association but, similar to the parent peptide, was able to readily solubilize phospholipid vesicles. Furthermore, 5A, unlike the parent peptide 37pA, was not hemolytic (37pA, 27+/-2% RBC lysis, 2 h, 18 microm). Finally, the 5A peptide stimulated cholesterol and phospholipid efflux by the ABCA1 transporter with higher specificity (ABCA1-transfected versus untransfected cells) than 37pA (5A, 9.7+/-0.77%, 18 h, 18 microm versus 1.5+/-0.27%, 18 h, 18 microm (p<0.0001); 37pA, 7.4+/-0.85%, 18 h, 18 microm versus 5.8+/-0.20%, 18 h, 18 microm (p=0.03)). In summary, we describe a novel bihelical peptide with asymmetry in the lipid affinity of its helices and properties similar to apoA-I in terms of specificity for cholesterol efflux by the ABCA1 transporter and low cytotoxicity.
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Affiliation(s)
- Amar A Sethi
- Lipoprotein Metabolism Section, Pulmonary and Vascular Medicine Branch, NHLBI, National Institutes of Health, Bethesda, Maryland 20892-1508, USA
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48
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Wool GD, Reardon CA, Getz GS. Apolipoprotein A-I mimetic peptide helix number and helix linker influence potentially anti-atherogenic properties. J Lipid Res 2008; 49:1268-83. [PMID: 18323574 DOI: 10.1194/jlr.m700552-jlr200] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We hypothesize that apolipoprotein A-I (apoA-I) mimetic peptides better mimicking the punctuated alpha-helical repeats of full-length apoA-I are more anti-inflammatory and anti-atherogenic. This study compares a monomeric apoA-I mimetic helix to three different tandem helix peptides in vitro: 4F (18 mer), 4F-proline-4F (37 mer, Pro), 4F-alanine-4F (37 mer, Ala), and 4F-KVEPLRA-4F [the human apoA-I 4/5 interhelical sequence (IHS), 43 mer]. All peptides cleared turbid lipid suspensions, with 4F being most effective. In contrast to lipid clearance, tandem peptides were more effective at remodeling mouse HDL. All four peptides displaced apoA-I and apoE from the HDL, leaving a larger particle containing apoA-II and peptide. Peptide-remodeled HDL particles show no deficit in ABCG1 cholesterol efflux despite the loss of the majority of apoA-I. Tandem peptides show greater ability to efflux cholesterol from lipid-loaded murine macrophages, compared with 4F. Although 4F inhibited oxidation of purified mouse LDL, the Ala tandem peptide increased oxidation. We compared several tandem 4F-based peptides with monomeric 4F in assays that correlated with suggested anti-inflammatory/anti-atherogenic pathways. Tandem 4F-based peptides, which better mimic full-length apoA-I, exceed monomeric 4F in HDL remodeling and cholesterol efflux but not LDL oxidation protection. In addition, apoA-I mimetic peptides may increase reverse cholesterol transport through both ABCA1 as well as ABCG1 pathways.
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Affiliation(s)
- Geoffrey D Wool
- The University of Chicago, Department of Pathology, Chicago, IL, USA
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49
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Oram JF, Wolfbauer G, Tang C, Davidson WS, Albers JJ. An amphipathic helical region of the N-terminal barrel of phospholipid transfer protein is critical for ABCA1-dependent cholesterol efflux. J Biol Chem 2008; 283:11541-9. [PMID: 18287097 DOI: 10.1074/jbc.m800117200] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phospholipid lipid transfer protein (PLTP) mimics high-density lipoprotein apolipoproteins in removing cholesterol and phospholipids from cells through the ATP-binding cassette transporter A1 (ABCA1). Because amphipathic alpha-helices are the structural determinants for ABCA1 interactions, we examined the ability of synthetic peptides corresponding to helices in PLTP to remove cellular cholesterol by the ABCA1 pathway. Of the seven helices tested, only one containing PLTP residues 144-163 (p144), located at the tip of the N-terminal barrel, promoted ABCA1-dependent cholesterol efflux and stabilized ABCA1 protein. Mutating methionine 159 (Met-159) in this helix in PLTP to aspartate (M159D) or glutamate (M159E) nearly abolished the ability of PLTP to remove cellular cholesterol and dramatically reduced PLTP binding to phospholipid vesicles and its phospholipid transfer activity. These mutations impaired PLTP binding to ABCA1-generated lipid domains and PLTP-mediated stabilization of ABCA1 but increased PLTP binding to ABCA1. PLTP interactions with ABCA1 also mimicked apolipoproteins in activating Janus kinase 2; however, the M159D/E mutants were also able to activate this kinase. Structural analyses showed that the M159D/E mutations had only minor effects on PLTP conformation. These findings indicate that PLTP helix 144-163 is critical for removing lipid domains formed by ABCA1, stabilizing ABCA1 protein, interacting with phospholipids, and promoting phospholipid transfer. Direct interactions with ABCA1 and activation of signaling pathways likely involve other structural determinants of PLTP.
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Affiliation(s)
- John F Oram
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, Box 356426, University of Washington, Seattle, Washington 98195, USA.
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50
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Shao B, Oda MN, Oram JF, Heinecke JW. Myeloperoxidase: an inflammatory enzyme for generating dysfunctional high density lipoprotein. Curr Opin Cardiol 2008; 21:322-8. [PMID: 16755201 DOI: 10.1097/01.hco.0000231402.87232.aa] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW Evidence indicates that high density lipoprotein (HDL) is cardioprotective and that several mechanisms are involved. One important pathway is a membrane-associated ATP-binding cassette transporter, ABCA1, that clears cholesterol from macrophage foam cells. Anti-inflammatory and antioxidant properties also might contribute to HDL's ability to inhibit atherosclerosis. RECENT FINDINGS Myeloperoxidase targets HDL for oxidation, raising the possibility that the enzyme provides a specific mechanism for generating dysfunctional HDL in humans. Myeloperoxidase-dependent oxidation of apolipoprotein A-I, the major protein in HDL, blocks HDL's ability to remove excess cholesterol from cells by the ABCA1 pathway. Analysis of mutated forms of apoA-I and oxidized apoA-I treated with methionine sulfoxide reductase implicate oxidation of specific tyrosine and methionine residues in impairing the ABCA1 transport activity of apoA-I. The crystal structure of lipid-free apoA-I suggests that such oxidative damage might disrupt negatively charged regions on the protein's surface or alter its remodeling, resulting in conformations that fail to interact with ABCA1. SUMMARY Oxidation of HDL by myeloperoxidase may represent a specific molecular mechanism for converting the cardioprotective lipoprotein into a dysfunctional form, raising the possibility that the enzyme represents a potential therapeutic target for preventing vascular disease in humans. Moreover, oxidized HDL might prove useful as a blood marker for clinically significant cardiovascular disease in humans.
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Affiliation(s)
- Baohai Shao
- Department of Medicine, University of Washington, Seattle, 98195, USA
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