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Kalayci A, Gibson CM, Ridker PM, Wright SD, Kingwell BA, Korjian S, Chi G, Lee JJ, Tricoci P, Kazmi SH, Fitzgerald C, Shaunik A, Berman G, Duffy D, Libby P. ApoA-I Infusion Therapies Following Acute Coronary Syndrome: Past, Present, and Future. Curr Atheroscler Rep 2022; 24:585-597. [PMID: 35524914 PMCID: PMC9236992 DOI: 10.1007/s11883-022-01025-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/25/2022] [Indexed: 11/24/2022]
Abstract
PURPOSE OF REVIEW The elevated adverse cardiovascular event rate among patients with low high-density lipoprotein cholesterol (HDL-C) formed the basis for the hypothesis that elevating HDL-C would reduce those events. Attempts to raise endogenous HDL-C levels, however, have consistently failed to show improvements in cardiovascular outcomes. However, steady-state HDL-C concentration does not reflect the function of this complex family of particles. Indeed, HDL functions correlate only weakly with serum HDL-C concentration. Thus, the field has pivoted from simply raising the quantity of HDL-C to a focus on improving the putative anti-atherosclerotic functions of HDL particles. Such functions include the ability of HDL to promote the efflux of cholesterol from cholesterol-laden macrophages. Apolipoprotein A-I (apoA-I), the signature apoprotein of HDL, may facilitate the removal of cholesterol from atherosclerotic plaque, reduce the lesional lipid content and might thus stabilize vulnerable plaques, thereby reducing the risk of cardiac events. Infusion of preparations of apoA-I may improve cholesterol efflux capacity (CEC). This review summarizes the development of apoA-I therapies, compares their structural and functional properties and discusses the findings of previous studies including their limitations, and how CSL112, currently being tested in a phase III trial, may overcome these challenges. RECENT FINDINGS Three major ApoA-I-based approaches (MDCO-216, CER-001, and CSL111/CSL112) have aimed to enhance reverse cholesterol transport. These three therapies differ considerably in both lipid and protein composition. MDCO-216 contains recombinant ApoA-I Milano, CER-001 contains recombinant wild-type human ApoA-I, and CSL111/CSL112 contains native ApoA-I isolated from human plasma. Two of the three agents studied to date (apoA-1 Milano and CER-001) have undergone evaluation by intravascular ultrasound imaging, a technique that gauges lesion volume well but does not assess other important variables that may relate to clinical outcomes. ApoA-1 Milano and CER-001 reduce lecithin-cholesterol acyltransferase (LCAT) activity, potentially impairing the function of HDL in reverse cholesterol transport. Furthermore, apoA-I Milano can compete with and alter the function of the recipient's endogenous apoA-I. In contrast to these agents, CSL112, a particle formulated using human plasma apoA-I and phosphatidylcholine, increases LCAT activity and does not lead to the malfunction of endogenous apoA-I. CSL112 robustly increases cholesterol efflux, promotes reverse cholesterol transport, and now is being tested in a phase III clinical trial. Phase II-b studies of MDCO-216 and CER-001 failed to produce a significant reduction in coronary plaque volume as assessed by IVUS. However, the investigation to determine whether the direct infusion of a reconstituted apoA-I reduces post-myocardial infarction coronary events is being tested using CSL112, which is dosed at a higher level than MDCO-216 and CER-001 and has more favorable pharmacodynamics.
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Affiliation(s)
- Arzu Kalayci
- Division of Cardiovascular Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - C Michael Gibson
- Division of Cardiovascular Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
- Baim Institute for Clinical Research, Boston, MA, USA
| | - Paul M Ridker
- Center for Cardiovascular Disease Prevention, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | | | | | - Serge Korjian
- Division of Cardiovascular Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Gerald Chi
- Division of Cardiovascular Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Jane J Lee
- Baim Institute for Clinical Research, Boston, MA, USA
| | | | - S Hassan Kazmi
- Division of Cardiovascular Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Clara Fitzgerald
- Division of Cardiovascular Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | | | - Gail Berman
- Paratek Pharmaceuticals, King of Prussia, PA, USA
| | | | - Peter Libby
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA.
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2
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Chroni A, Kardassis D. HDL Dysfunction Caused by Mutations in apoA-I and Other Genes that are Critical for HDL Biogenesis and Remodeling. Curr Med Chem 2019. [DOI: 10.2174/0929867325666180313114950] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The “HDL hypothesis” which suggested that an elevation in HDL cholesterol
(HDL-C) levels by drugs or by life style changes should be paralleled by a decrease in the
risk for Cardiovascular Disease (CVD) has been challenged by recent epidemiological and
clinical studies using HDL-raising drugs. HDL components such as proteins, lipids or small
RNA molecules, but not cholesterol itself, possess various atheroprotective functions in different
cell types and accumulating evidence supports the new hypothesis that HDL functionality
is more important than HDL-C levels for CVD risk prediction. Thus, the detailed characterization
of changes in HDL composition and functions in various pathogenic conditions
is critically important in order to identify new biomarkers for diagnosis, prognosis and therapy
monitoring of CVD. Here we provide an overview of how HDL composition, size and
functionality are affected in patients with monogenic disorders of HDL metabolism due to
mutations in genes that participate in the biogenesis and the remodeling of HDL. We also review
the findings from various mouse models with genetic disturbances in the HDL biogenesis
pathway that have been generated for the validation of the data obtained in human patients
and how these models could be utilized for the evaluation of novel therapeutic strategies such
as the use of adenovirus-mediated gene transfer technology that aim to correct HDL abnormalities.
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Affiliation(s)
- Angeliki Chroni
- Institute of Biosciences and Applications, National Center for Scientific Research , Greece
| | - Dimitris Kardassis
- Department of Basic Medical Sciences, University of Crete Medical School and Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology of Hellas, Heraklion 71003, Greece
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3
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Del Giudice R, Domingo-Espín J, Iacobucci I, Nilsson O, Monti M, Monti DM, Lagerstedt JO. Structural determinants in ApoA-I amyloidogenic variants explain improved cholesterol metabolism despite low HDL levels. Biochim Biophys Acta Mol Basis Dis 2017; 1863:3038-3048. [PMID: 28887204 DOI: 10.1016/j.bbadis.2017.09.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/30/2017] [Accepted: 09/01/2017] [Indexed: 11/19/2022]
Abstract
Twenty Apolipoprotein A-I (ApoA-I) variants are responsible for a systemic hereditary amyloidosis in which protein fibrils can accumulate in different organs, leading to their failure. Several ApoA-I amyloidogenic mutations are also associated with hypoalphalipoproteinemia, low ApoA-I and high-density lipoprotein (HDL)-cholesterol plasma levels; however, subjects affected by ApoA-I-related amyloidosis do not show a higher risk of cardiovascular diseases (CVD). The structural features, the lipid binding properties and the functionality of four ApoA-I amyloidogenic variants were therefore inspected in order to clarify the paradox observed in the clinical phenotype of the affected subjects. Our results show that ApoA-I amyloidogenic variants are characterized by a different oligomerization pattern and that the position of the mutation in the ApoA-I sequence affects the molecular structure of the formed HDL particles. Although lipidation increases ApoA-I proteins stability, all the amyloidogenic variants analyzed show a lower affinity for lipids, both in vitro and in ex vivo mouse serum. Interestingly, the lower efficiency at forming HDL particles is compensated by a higher efficiency at catalysing cholesterol efflux from macrophages. The decreased affinity of ApoA-I amyloidogenic variants for lipids, together with the increased efficiency in the cholesterol efflux process, could explain why, despite the unfavourable lipid profile, patients affected by ApoA-I related amyloidosis do not show a higher CVD risk.
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Affiliation(s)
- Rita Del Giudice
- Department of Experimental Medical Science, Lund University, 221 84 Lund, Sweden.
| | - Joan Domingo-Espín
- Department of Experimental Medical Science, Lund University, 221 84 Lund, Sweden
| | - Ilaria Iacobucci
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy; CEINGE Biotecnologie Avanzate, 80145 Naples, Italy
| | - Oktawia Nilsson
- Department of Experimental Medical Science, Lund University, 221 84 Lund, Sweden
| | - Maria Monti
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy; Istituto Nazionale di Biostrutture e Biosistemi (INBB), Rome, Italy
| | - Daria Maria Monti
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy; Istituto Nazionale di Biostrutture e Biosistemi (INBB), Rome, Italy
| | - Jens O Lagerstedt
- Department of Experimental Medical Science, Lund University, 221 84 Lund, Sweden.
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4
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Fernández-de Retana S, Montañola A, Marazuela P, De La Cuesta M, Batlle A, Fatar M, Grudzenski S, Montaner J, Hernández-Guillamon M. Intravenous treatment with human recombinant ApoA-I Milano reduces beta amyloid cerebral deposition in the APP23-transgenic mouse model of Alzheimer's disease. Neurobiol Aging 2017; 60:116-128. [PMID: 28941727 DOI: 10.1016/j.neurobiolaging.2017.08.028] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 08/18/2017] [Accepted: 08/26/2017] [Indexed: 12/31/2022]
Abstract
Beyond the crucial role of apolipoprotein A-I (ApoA-I) on peripheral cholesterol metabolism, this apolipoprotein has also been implicated in beta amyloid (Aβ)-related neuropathologies. ApoA-I-Milano (M) is a mutated variant, which showed increased vasoprotective properties compared to ApoA-I-wild type in models of atherosclerosis and cardiovascular damage. We speculated that ApoA-I-M may also protect Aβ-affected vasculature and reverse some of the pathological features associated with Alzheimer's disease (AD). For this purpose, we produced and characterized human recombinant ApoA-I-wild type and ApoA-I-M proteins. Both of them were able to avoid the aggregation of Aβ in vitro, even though recombinant ApoA-I-M was significantly more effective in protecting endothelial cells from Aβ(1-42)-toxicity. Next, we determined the effect of chronic intravenous administration of rApoA-I-M in the APP23-transgenic mouse model of AD. We found reduced cerebral Aβ levels in mice that received rApoA-I-M, which were accompanied by a lower expression of astrocyte and microglia neuroinflammatory markers. Our results suggest an applicability of this molecule as a therapeutic candidate for protecting the brain in AD.
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Affiliation(s)
- Sofía Fernández-de Retana
- Neurovascular Research Laboratory, Vall d'Hebron Research Insitute, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Alex Montañola
- Neurovascular Research Laboratory, Vall d'Hebron Research Insitute, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Paula Marazuela
- Neurovascular Research Laboratory, Vall d'Hebron Research Insitute, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Maialen De La Cuesta
- Neurovascular Research Laboratory, Vall d'Hebron Research Insitute, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Aina Batlle
- Neurovascular Research Laboratory, Vall d'Hebron Research Insitute, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Marc Fatar
- Department of Neurology, Universitätsmedizin Mannheim, Heidelberg University, Mannheim, Germany
| | - Saskia Grudzenski
- Department of Neurology, Universitätsmedizin Mannheim, Heidelberg University, Mannheim, Germany
| | - Joan Montaner
- Neurovascular Research Laboratory, Vall d'Hebron Research Insitute, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Mar Hernández-Guillamon
- Neurovascular Research Laboratory, Vall d'Hebron Research Insitute, Universitat Autònoma de Barcelona, Barcelona, Spain.
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5
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Di Bartolo BA, Schwarz N, Andrews J, Nicholls SJ. Infusional high-density lipoproteins therapies as a novel strategy for treating atherosclerosis. Arch Med Sci 2017; 13:210-214. [PMID: 28144273 PMCID: PMC5206363 DOI: 10.5114/aoms.2016.60941] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 11/18/2015] [Indexed: 01/18/2023] Open
Abstract
High-density lipoproteins (HDL) have received considerable interest as a target for the development of novel anti-atherosclerotic agents beyond conventional approaches to lipid lowering. While a number of approaches have focused on modifying remodeling and expression pathways implicated in the regulation of HDL levels, an additional approach involves simply infusions of delipidated HDL. Several groups have advanced HDL infusions to clinical development with intriguing signs suggesting potentially favorable impacts at the level of the artery wall. The findings of early studies of infusional HDL therapies will be reviewed.
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Affiliation(s)
- Belinda A Di Bartolo
- South Australian Health and Medical Research Institute, University of Adelaide, Adelaide, Australia
| | - Nisha Schwarz
- South Australian Health and Medical Research Institute, University of Adelaide, Adelaide, Australia
| | - Jordan Andrews
- South Australian Health and Medical Research Institute, University of Adelaide, Adelaide, Australia
| | - Stephen J Nicholls
- South Australian Health and Medical Research Institute, University of Adelaide, Adelaide, Australia
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6
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Andrews J, Janssan A, Nguyen T, Pisaniello AD, Scherer DJ, Kastelein JJP, Merkely B, Nissen SE, Ray K, Schwartz GG, Worthley SG, Keyserling C, Dasseux JL, Butters J, Girardi J, Miller R, Nicholls SJ. Effect of serial infusions of reconstituted high-density lipoprotein (CER-001) on coronary atherosclerosis: rationale and design of the CARAT study. Cardiovasc Diagn Ther 2017; 7:45-51. [PMID: 28164012 DOI: 10.21037/cdt.2017.01.01] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND High-density lipoprotein (HDL) is believed to have atheroprotective properties, but an effective HDL-based therapy remains elusive. Early studies have suggested that infusion of reconstituted HDL promotes reverse cholesterol transport and vascular reactivity. The CER-001 Atherosclerosis Regression Acute Coronary Syndrome Trial (CARAT) is investigating the impact of infusing an engineered pre-beta HDL mimetic containing sphingomyelin (SM) and dipalmitoyl phosphatidlyglycerol (CER-001) on coronary atheroma volume in patients with a recent acute coronary syndrome (ACS). METHODS The CARAT is a phase 2, multicenter trial in which 292 patients with an ACS undergoing intracoronary ultrasonography and showing percent atheroma volume (PAV) greater than 30% are randomly assigned to treatment with ten infusions of CER-001 3 mg/kg or matching placebo, administered at weekly intervals. Intracoronary ultrasonography is repeated at the end of the treatment period. RESULTS The primary endpoint is the nominal change in PAV. Safety and tolerability will also be evaluated. CONCLUSIONS CARAT will establish whether serial 3 mg/kg infusions of an engineered pre-beta HDL mimetic containing SM and dipalmitoyl phosphatidlyglycerol (CER-001) will regress atherosclerotic plaque in patients with a recent ACS.
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Affiliation(s)
- Jordan Andrews
- South Australian Health and Medical Research Institute, University of Adelaide, Adelaide, Australia
| | - Alex Janssan
- South Australian Health and Medical Research Institute, University of Adelaide, Adelaide, Australia
| | - Tracy Nguyen
- South Australian Health and Medical Research Institute, University of Adelaide, Adelaide, Australia
| | - Anthony D Pisaniello
- South Australian Health and Medical Research Institute, University of Adelaide, Adelaide, Australia
| | - Daniel J Scherer
- South Australian Health and Medical Research Institute, University of Adelaide, Adelaide, Australia
| | - John J P Kastelein
- Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Bela Merkely
- Heart and Vascular Center, Semmelweis University, Budapest, Hungary
| | | | - Kausik Ray
- School of Public Health, Imperial College London, London, UK
| | | | - Stephen G Worthley
- South Australian Health and Medical Research Institute, University of Adelaide, Adelaide, Australia
| | | | | | - Julie Butters
- South Australian Health and Medical Research Institute, University of Adelaide, Adelaide, Australia
| | - Jacinta Girardi
- South Australian Health and Medical Research Institute, University of Adelaide, Adelaide, Australia
| | - Rosemary Miller
- South Australian Health and Medical Research Institute, University of Adelaide, Adelaide, Australia
| | - Stephen J Nicholls
- South Australian Health and Medical Research Institute, University of Adelaide, Adelaide, Australia
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7
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Di Bartolo BA, Scherer DJ, Nicholls SJ. Inducing apolipoprotein A-I synthesis to reduce cardiovascular risk: from ASSERT to SUSTAIN and beyond. Arch Med Sci 2016; 12:1302-1307. [PMID: 27904522 PMCID: PMC5108390 DOI: 10.5114/aoms.2016.62906] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 11/17/2015] [Indexed: 12/29/2022] Open
Abstract
Increasing attention has focused on efforts to promote the biological activities of high-density lipoproteins (HDL) in order to reduce cardiovascular risk. Targeting apolipoprotein A-I (apoA-I), the major protein carried on HDL particles, represents an attractive approach to promoting HDL by virtue of its ability to increase endogenous synthesis of functional HDL particles. A number of pharmacological strategies that target apoA-I, including upregulation of its production with the bromodomain and extraterminal (BET) protein inhibitor RVX-208, development of short peptide sequences that mimic its action, and administration as a component of reconstituted HDL particles, have undergone clinical development. The impact of these approaches on cardiovascular biomarkers will be reviewed.
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Affiliation(s)
- Belinda A Di Bartolo
- South Australian Health and Medical Research Institute, University of Adelaide, Adelaide, Australia
| | - Daniel J Scherer
- South Australian Health and Medical Research Institute, University of Adelaide, Adelaide, Australia
| | - Stephen J Nicholls
- South Australian Health and Medical Research Institute, University of Adelaide, Adelaide, Australia
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8
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Bisgaier CL, Ackermann R, Rea T, Rodrigueza WV, Hartman D. ApoA-IMilano phospholipid complex (ETC-216) infusion in human volunteers. Insights into the phenotypic characteristics of ApoA-IMilano carriers. Pharmacol Res 2016; 111:86-99. [DOI: 10.1016/j.phrs.2016.05.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Revised: 05/02/2016] [Accepted: 05/02/2016] [Indexed: 12/15/2022]
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9
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Pownall HJ, Gotto AM. New Insights into the High-Density Lipoprotein Dilemma. Trends Endocrinol Metab 2016; 27:44-53. [PMID: 26673122 PMCID: PMC4707953 DOI: 10.1016/j.tem.2015.11.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 11/07/2015] [Accepted: 11/09/2015] [Indexed: 12/21/2022]
Abstract
Although high-density lipoprotein-cholesterol (HDL-C) concentration is a negative risk factor for atherosclerotic cardiovascular disease (CVD), efforts to reduce CVD risk by raising HDL-C have not been uniformly successful. Many studies have shown that alcohol consumption, that increases plasma HDL-C concentration, reduces CVD incidence. However, recent genetic studies in large populations have not only removed HDL-C from the causal link between plasma HDL-C concentration and reduced CVD risk, but also suggest that the association is weak. We propose here that the cardioprotective effects of alcohol are mediated by the interaction of its terminal metabolite, acetate, with the adipocyte free fatty acid receptor 2 (FFAR2), which elicits a profound antilipolytic effect that may increase insulin sensitivity without necessarily raising plasma HDL-C concentration.
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Affiliation(s)
- Henry J. Pownall
- Houston Methodist Research Institute and Weill Cornell Medical College, 6670 Bertner Avenue, Houston TX 77030
| | - Antonio M. Gotto
- Houston Methodist Research Institute and Weill Cornell Medical College, 1305 York Avenue, New York, NY, USA
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10
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Jackson WD, Woollard KJ. Targeting monocyte and macrophage subpopulations for immunotherapy: a patent review (2009 - 2013). Expert Opin Ther Pat 2014; 24:779-90. [PMID: 24773534 DOI: 10.1517/13543776.2014.914495] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
INTRODUCTION Monocytes and macrophages are heterogeneous populations of effector cells in the innate immune system. Once thought to be obligatory precursors for macrophages, monocytes are now known to have several distinct sub-populations and their own independent functions. This separation of the two lineages has opened new therapeutic avenues in inflammation and created new technologies targeting the mononuclear phagocyte system (MPS). AREAS COVERED A search of Google Patents and PatentScope has revealed numerous patents targeting monocytes and macrophages. This review will focus on seven patents from 2009 to 2013, utilizing autologous monocyte and macrophage adoptive transfer, genetic manipulation of the MPS, therapeutic nanoparticles and liposomes or combinations of these strategies. Patents that target monocyte recruitment are also briefly reviewed. EXPERT OPINION While monocyte and macrophage targeting has yielded some promising results in animal models, these often fail to translate well to successful clinical trials. The paradigm of how cells in the MPS interact and evolve is constantly being updated, and caution must be exercised in developing immunomodulatory agents until this relationship is better understood.
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Affiliation(s)
- William D Jackson
- Imperial College London, Department of Medicine, Division of Immunology and Inflammation , London, W12 ONN , UK
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11
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Gursky O, Jones MK, Mei X, Segrest JP, Atkinson D. Structural basis for distinct functions of the naturally occurring Cys mutants of human apolipoprotein A-I. J Lipid Res 2013; 54:3244-57. [PMID: 24038317 DOI: 10.1194/jlr.r037911] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
HDL removes cell cholesterol and protects against atherosclerosis. ApoA-I provides a flexible structural scaffold and an important functional ligand on the HDL surface. We propose structural models for apoA-I(Milano) (R173C) and apoA-I(Paris) (R151C) mutants that show high cardioprotection despite low HDL levels. Previous studies established that two apoA-I molecules encircle HDL in an antiparallel, helical double-belt conformation. Recently, we solved the atomic structure of lipid-free Δ(185-243)apoA-I and proposed a conformational ensemble for apoA-I(WT) on HDL. Here we modify this ensemble to understand how intermolecular disulfides involving C173 or C151 influence protein conformation. The double-belt conformations are modified by belt rotation, main-chain unhinging around Gly, and Pro-induced helical bending, and they are verified by comparison with previous experimental studies and by molecular dynamics simulations of apoA-I(Milano) homodimer. In our models, the molecular termini repack on various-sized HDL, while packing around helix-5 in apoA-I(WT), helix-6 in apoA-I(Paris), or helix-7 in apoA-I(Milano) homodimer is largely conserved. We propose how the disulfide-induced constraints alter the protein conformation and facilitate dissociation of the C-terminal segment from HDL to recruit additional lipid. Our models unify previous studies of apoA-I(Milano) and demonstrate how the mutational effects propagate to the molecular termini, altering their conformations, dynamics, and function.
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Affiliation(s)
- Olga Gursky
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118
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12
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Kempen HJ, Gomaraschi M, Bellibas SE, Plassmann S, Zerler B, Collins HL, Adelman SJ, Calabresi L, Wijngaard PLJ. Effect of repeated apoA-IMilano/POPC infusion on lipids, (apo)lipoproteins, and serum cholesterol efflux capacity in cynomolgus monkeys. J Lipid Res 2013; 54:2341-53. [PMID: 23828780 DOI: 10.1194/jlr.m033779] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
MDCO-216, a complex of dimeric recombinant apoA-IMilano (apoA-IM) and palmitoyl-oleoyl-phosphatidylcholine (POPC), was administered to cynomolgus monkeys at 30, 100, and 300 mg/kg every other day for a total of 21 infusions, and effects on lipids, (apo)lipoproteins, and ex-vivo cholesterol efflux capacity were monitored. After 7 or 20 infusions, free cholesterol (FC) and phospholipids (PL) were strongly increased, and HDL-cholesterol (HDL-C), apoA-I, and apoA-II were strongly decreased. We then measured short-term effects on apoA-IM, lipids, and (apo)lipoproteins after the first or the last infusion. After the first infusion, PL and FC went up in the HDL region and also in the LDL and VLDL regions. ApoE shifted from HDL to LDL and VLDL regions, while ApoA-IM remained located in the HDL region. On day 41, ApoE levels were 8-fold higher than on day 1, and FC, PL, and apoE resided mostly in LDL and VLDL regions. Drug infusion quickly decreased the endogenous cholesterol esterification rate. ABCA1-mediated cholesterol efflux on day 41 was markedly increased, whereas scavenger receptor type B1 (SRB1) and ABCG1-mediated effluxes were only weakly increased. Strong increase of FC is due to sustained stimulation of ABCA1-mediated efflux, and drop in HDL and formation of large apoE-rich particles are due to lack of LCAT activation.
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13
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Larach DB, deGoma EM, Rader DJ. Targeting high density lipoproteins in the prevention of cardiovascular disease? Curr Cardiol Rep 2013; 14:684-91. [PMID: 22991041 DOI: 10.1007/s11886-012-0317-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Recent studies involving HDL-raising therapeutics have greatly changed our understanding of this field. Despite effectively raising HDL-C levels, niacin remains of uncertain clinical benefit. Synthetic niacin receptor agonists are unlikely to raise HDL-C or have other beneficial effects on plasma lipids. Despite the failure in phase 3 of 2 CETP inhibitors, 2 potent CETP inhibitors that raise HDL-C levels by >100 % (and reduce LDL-C substantially) are in late stage clinical development. Infusions of recombinant HDL containing 'wild-type' apoA-I or apoA-I Milano, as well as autologous delipidated HDL, all demonstrated promising early results, and remain in clinical development. A small molecule that causes upregulation of endogenous apoA-I production is also in clinical development. Finally, upregulation of macrophage cholesterol efflux pathways through agonism of liver X receptors or antagonism of miR-33 remains of substantial interest. The field of HDL therapeutics is poised to transition from the 'HDL-cholesterol hypothesis' to the 'HDL flux hypothesis' in which the impact on flux from macrophage to feces is deemed to be of greater therapeutic benefit than the increase in steady-state concentrations of HDL cholesterol.
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Affiliation(s)
- Daniel B Larach
- Perelman School of Medicine at the University of Pennsylvania, Philadelphia, 19104, USA.
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14
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Murphy AJ, Funt S, Gorman D, Tall AR, Wang N. Pegylation of high-density lipoprotein decreases plasma clearance and enhances antiatherogenic activity. Circ Res 2013; 113:e1-e9. [PMID: 23613182 DOI: 10.1161/circresaha.113.301112] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
RATIONALE Infusions of apolipoprotein AI (apoAI), mimetic peptides, or high-density lipoprotein (HDL) remain a promising approach for the treatment of atherosclerotic coronary disease. However, rapid clearance leads to a requirement for repeated administration of large amounts of material and limits effective plasma concentrations. OBJECTIVE Because pegylation of purified proteins is commonly used as a method to increase their half-life in the circulation, we determined whether pegylation of apoAI or HDL would increase its plasma half-life and in turn its antiatherogenic potential. METHODS AND RESULTS Initial pegylation attempts using lipid-poor apoAI showed a marked tendency to form multi-pegylated (PEG) species with reduced ability to promote cholesterol efflux from macrophage foam cells. However, pegylation of human holo-HDL or reconstituted phospholipid/apoAI particles (rHDL) led to selective N-terminal monopegylation of apoAI with full preservation of cholesterol efflux activity. The plasma clearance of PEG-rHDL was estimated after injection into hypercholesterolemic Apoe-/- mice; the half-life of pegylated PEG-apoAI after injection of PEG-rHDL was increased ≈7-fold compared with apoAI in nonpegylated rHDL. In comparison with nonpegylated rHDL, infusion of PEG-rHDL (40 mg/kg) into hypercholesterolemic Apoe-/- mice led to more pronounced suppression of bone marrow myeloid progenitor cell proliferation and monocytosis, as well as reduced atherosclerosis and a stable plaque phenotype. CONCLUSIONS We describe a novel method for effective monopegylation of apoAI in HDL particles, in which lipid binding seems to protect against pegylation of key functional residues. Pegylation of apoAI in rHDL markedly increases its plasma half-life and enhances antiatherogenic properties in vivo.
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Affiliation(s)
- Andrew J Murphy
- Division of Molecular Medicine, Department of Medicine, Columbia University, New York, New York 10032, USA
| | - Samuel Funt
- Division of Molecular Medicine, Department of Medicine, Columbia University, New York, New York 10032, USA
| | - Darren Gorman
- Division of Molecular Medicine, Department of Medicine, Columbia University, New York, New York 10032, USA
| | - Alan R Tall
- Division of Molecular Medicine, Department of Medicine, Columbia University, New York, New York 10032, USA
| | - Nan Wang
- Division of Molecular Medicine, Department of Medicine, Columbia University, New York, New York 10032, USA
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15
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Chetty PS, Ohshiro M, Saito H, Dhanasekaran P, Lund-Katz S, Mayne L, Englander W, Phillips MC. Effects of the Iowa and Milano mutations on apolipoprotein A-I structure and dynamics determined by hydrogen exchange and mass spectrometry. Biochemistry 2012; 51:8993-9001. [PMID: 23066790 DOI: 10.1021/bi300926j] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The Iowa point mutation in apolipoprotein A-I (G26R) leads to a systemic amyloidosis condition, and the Milano mutation (R173C) is associated with hypoalphalipoproteinemia, a reduced plasma level of high-density lipoprotein. To probe the structural effects that lead to these outcomes, we used amide hydrogen-deuterium exchange coupled with a fragment separation/mass spectrometry analysis (HX MS). The Iowa mutation inserts an arginine residue into the nonpolar face of an α-helix that spans residues 7-44 and causes changes in structure and structural dynamics. This helix unfolds, and other helices in the N-terminal helix bundle domain are destabilized. The segment encompassing residues 116-158, largely unstructured in wild-type apolipoprotein A-I, becomes helical. The helix spanning residues 81-115 is destabilized by 2 kcal/mol, increasing the small fraction of time it is transiently unfolded to ≥1%, which allows proteolysis at residue 83 in vivo over time, releasing an amyloid-forming peptide. The Milano mutation situated on the polar face of the helix spanning residues 147-178 destabilizes the helix bundle domain only moderately, but enough to allow cysteine-mediated dimerization that leads to the altered functionality of this variant. These results show how the HX MS approach can provide a powerful means of monitoring, in a nonperturbing way and at close to amino acid resolution, the structural, dynamic, and energetic consequences of biologically interesting point mutations.
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Affiliation(s)
- Palaniappan Sevugan Chetty
- Lipid Research Group, Gastroenterology, Hepatology and Nutrition Division, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104-4318, United States
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16
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Abstract
PURPOSE OF REVIEW HDL cholesterol concentration is inversely correlated with cardiovascular disease and has a wide range of functions involved in many systems. The purpose of this review is to summarize HDL functionality, its relevance to atherosclerosis and factors affecting HDL functions. RECENT FINDINGS The contribution of HDL to reverse cholesterol transport may not be as great as first envisaged. However, it still plays an important role in cholesterol efflux from peripheral tissues. The capacity of HDL to promote cellular cholesterol efflux in an ex-vivo model has been reported to correlate more closely with carotid intima-media thickness than HDL cholesterol concentration. Recently, a variety of other functions of HDL have been described including antimicrobial, antioxidant, antiglycation, anti-inflammatory, nitric oxide--inducing, antithrombotic and antiatherogenic activity and immune modulation as well as a potential role in glucose homeostasis, diabetes pathophysiology and complications. SUMMARY HDL has a wide range of functions some of which are independent of its cholesterol content. Its cargo of apolipoproteins, various proteins and phospholipids contributes most to its various functions. These functions are affected by a number of genetic, physiological and pathological factors.
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Affiliation(s)
- Handrean Soran
- University Department of Medicine, Central Manchester and Manchester Children University Hospital NHS Foundation Trust, School of Biomedicine, University of Manchester, Manchester, UK
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18
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Ma CIJ, Beckstead JA, Thompson A, Hafiane A, Wang RHL, Ryan RO, Kiss RS. Tweaking the cholesterol efflux capacity of reconstituted HDL. Biochem Cell Biol 2012; 90:636-45. [PMID: 22607224 DOI: 10.1139/o2012-015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mechanisms to increase plasma high-density lipoprotein (HDL) or to promote egress of cholesterol from cholesterol-loaded cells (e.g., foam cells from atherosclerotic lesions) remain an important target to regress heart disease. Reconstituted HDL (rHDL) serves as a valuable vehicle to promote cellular cholesterol efflux in vitro and in vivo. rHDL were prepared with wild type apolipoprotein (apo) A-I and the rare variant, apoA-I Milano (M), and each apolipoprotein was reconstituted with phosphatidylcholine (PC) or sphingomyelin (SM). The four distinct rHDL generated were incubated with CHO cells, J774 macrophages, and BHK cells in cellular cholesterol efflux assays. In each cell type, apoA-I(M) SM-rHDL promoted the greatest cholesterol efflux. In BHK cells, the cholesterol efflux capacities of all four distinct rHDL were greatly enhanced by increased expression of ABCG1. Efflux to PC-containing rHDL was stimulated by transfection of a nonfunctional ABCA1 mutant (W590S), suggesting that binding to ABCA1 represents a competing interaction. This interpretation was confirmed by binding experiments. The data show that cholesterol efflux activity is dependent upon the apoA-I protein employed, as well as the phospholipid constituent of the rHDL. Future studies designed to optimize the efflux capacity of therapeutic rHDL may improve the value of this emerging intervention strategy.
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Affiliation(s)
- Cheng-I J Ma
- Cardiovascular Research Laboratories, Department of Medicine, Royal Victoria Hospital, 687 Pine Avenue West, Montreal, QC H3A 1A1, Canada
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19
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Ohnsorg PM, Mary JL, Rohrer L, Pech M, Fingerle J, von Eckardstein A. Trimerized apolipoprotein A-I (TripA) forms lipoproteins, activates lecithin:cholesterol acyltransferase, elicits lipid efflux, and is transported through aortic endothelial cells. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1811:1115-23. [DOI: 10.1016/j.bbalip.2011.09.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 08/11/2011] [Accepted: 09/02/2011] [Indexed: 02/03/2023]
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20
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Recombinant HDL(Milano) exerts greater anti-inflammatory and plaque stabilizing properties than HDL(wild-type). Atherosclerosis 2011; 220:72-7. [PMID: 22030095 DOI: 10.1016/j.atherosclerosis.2011.10.006] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 09/29/2011] [Accepted: 10/05/2011] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The aim of this study was to compare the effects of HDL(Milano) and HDL(wild-type), on regression and stabilization of atherosclerosis. METHODS Atherosclerotic New Zealand White rabbits received 2 infusions, 4 days apart, of HDL(Milano) (75mg/kg of apoA-I(Milano)), HDL(wild-type) (75mg/kg apoA-I(wild-type)) or placebo. Pre- and post-treatment plaque volume was assessed by MRI. Markers of plaque vulnerability and inflammation were evaluated. Liver and aortic cholesterol content, aortic ABCA-1 and liver SR-BI were quantified. The effect of apoA-I Milano and wild-type proteins on MCP-1 and COX-2 expression by macrophages was evaluated in vitro. RESULTS Both forms of HDL induced aortic plaque regression (-4.1% and -2.6% vs. pre-treatment in HDL(Milano) and HDL(wild-type) respectively, p<0.001 and p=0.009). A similar reduction in cholesterol content of aorta and liver was observed with both treatments vs. placebo. The expression of aortic ABCA-1 and hepatic SR-BI was significantly higher in both treated groups vs. placebo. A significantly reduced plaque macrophage density was observed in the HDL(Milano) vs. both HDL(wild-type) and placebo groups. Plaque levels of COX-2, MCP-1, Caspase-3 antigen and MMP-2 activity were significantly reduced in the HDL(Milano) vs. both HDL(wild-type) and placebo groups. In vitro studies showed that apoA-I(Milano) protein significantly reduced expression of COX-2 and MCP-1 in oxLDL loaded macrophages vs. apoA-I(wild-type). CONCLUSIONS Despite a similar effect on acute plaque regression, the infusion of HDL(Milano) exerts superior anti-inflammatory and plaque stabilizing effects than HDL(wild-type) in the short term.
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21
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Emerging therapeutic strategies to enhance HDL function. Lipids Health Dis 2011; 10:175. [PMID: 21985435 PMCID: PMC3200157 DOI: 10.1186/1476-511x-10-175] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Accepted: 10/10/2011] [Indexed: 02/02/2023] Open
Abstract
Epidemiologic studies indicate a strong inverse correlation between plasma levels of high-density lipoproteins (HDL) and cardiovascular disease (CVD). The most relevant cardioprotective mechanism mediated by HDL is thought to be reverse cholesterol transport (RCT). New insights in HDL biology and RCT have allowed the development of promising agents aimed to increase HDL function and promote atherosclerosis regression. In this regard, apo-AI analogs and CETP inhibitors dalcetrapib and anacetrapib have aroused a great interest and opened new expectations in the treatment of CVD.
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22
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Sorci-Thomas MG, Zabalawi M, Bharadwaj MS, Wilhelm AJ, Owen JS, Asztalos BF, Bhat S, Thomas MJ. Dysfunctional HDL containing L159R ApoA-I leads to exacerbation of atherosclerosis in hyperlipidemic mice. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:502-12. [PMID: 21944998 DOI: 10.1016/j.bbalip.2011.08.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 08/20/2011] [Accepted: 08/31/2011] [Indexed: 11/16/2022]
Abstract
The mutation L159R apoA-I or apoA-I(L159R) (FIN) is a single amino acid substitution within the sixth helical repeat of apoA-I. It is associated with a dominant negative phenotype, displaying hypoalphaproteinemia and an increased risk for atherosclerosis in humans. Mice lacking both mouse apoA-I and LDL receptor (LDL(-/-), apoA-I(-/-)) (double knockout or DKO) were crossed>9 generations with mice transgenic for human FIN to obtain L159R apoA-I, LDLr(-/-), ApoA-I(-/-) (FIN-DKO) mice. A similar cross was also performed with human wild-type (WT) apoA-I (WT-DKO). In addition, FIN-DKO and WT-DKO were crossed to obtain WT/FIN-DKO mice. To determine the effects of the apoA-I mutations on atherosclerosis, groups of each genotype were fed either chow or an atherogenic diet for 12weeks. Interestingly, the production of dysfunctional HDL-like particles occurred in DKO and FIN-DKO mice. These particles were distinct with respect to size, and their enrichment in apoE and cholesterol esters. Two-dimensional gel electrophoresis indicated that particles found in the plasma of FIN-DKO mice migrated as large α(3)-HDL. Atherosclerosis analysis showed that FIN-DKO mice developed the greatest extent of aortic cholesterol accumulation compared to all other genotypes, including DKO mice which lack any apoA-I. Taken together these data suggest that the presence of large apoE enriched HDL particles containing apoA-I L159R lack the normal cholesterol efflux promoting properties of HDL, rendering them dysfunctional and pro-atherogenic. In conclusion, large HDL-like particles containing apoE and apoA-I(L159R) contribute rather than protect against atherosclerosis, possibly through defective efflux properties and their potential for aggregation at their site of interaction in the aorta. 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)
- Mary G Sorci-Thomas
- Department of Pathology, Section on Lipid Sciences, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
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23
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Abstract
The burden of atherothrombotic cardiovascular disease remains high despite currently available optimum medical therapy. To address this substantial residual risk, the development of novel therapies that attempt to harness the atheroprotective functions of HDL is a major goal. These functions include the critical role of HDL in reverse cholesterol transport, and its anti-inflammatory, antithrombotic, and antioxidant activities. Discoveries in the past decade have shed light on the complex metabolic and antiatherosclerotic pathways of HDL. These insights have fueled the development of HDL-targeted drugs, which can be classified among four different therapeutic approaches: directly augmenting apolipoprotein A-I (apo A-I) levels, such as with apo A-I infusions and upregulators of endogenous apo A-I production; indirectly augmenting apo A-I and HDL-cholesterol levels, such as through inhibition of cholesteryl ester transfer protein or endothelial lipase, or through activation of the high-affinity niacin receptor GPR109A; mimicking the functionality of apo A-I with apo A-I mimetic peptides; and enhancing steps in the reverse cholesterol transport pathway, such as via activation of the liver X receptor or of lecithin-cholesterol acyltransferase.
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Affiliation(s)
- Emil M Degoma
- Division of Cardiovascular Medicine, University of Pennsylvania, Penn Tower, 6th Floor, 3400 Spruce Street, Philadelphia, PA 19104, USA.
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24
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Abstract
INTRODUCTION Increasing attention has focused on the role of high-density lipoprotein function as a target for cardiprotection. Apolipoprotein A-I(Milano) (AIM) involves a single amino-acid mutation of the major wild-type protein carried on high-density lipoprotein (HDL) particles. Early evidence of beneficial activities of AIM has stimulated support in its development as a potential therapy to reduce cardiovascular risk. AREAS COVERED The importance of HDL as a target and early data supporting the beneficial effects of AIM are reviewed. All clinical studies of AIM found in PubMed are reviewed. EXPERT OPINION ETC-216 represents a lipid-deplete form of HDL containing recombinant AIM. While early evidence suggests that administration of ETC-216 promotes rapid regression of coronary atherosclerosis, bringing this compound to clinical practice will require further trials that evaluate its impact on cardiovascular events.
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Affiliation(s)
- Stephen J Nicholls
- Heart & Vascular Institute, Cleveland Clinic, Department of Cardiovascular Medicine, Cleveland, OH 44195, USA.
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25
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26
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Tanaka M, Dhanasekaran P, Nguyen D, Nickel M, Takechi Y, Lund-Katz S, Phillips MC, Saito H. Influence of N-terminal helix bundle stability on the lipid-binding properties of human apolipoprotein A-I. Biochim Biophys Acta Mol Cell Biol Lipids 2010; 1811:25-30. [PMID: 21040803 DOI: 10.1016/j.bbalip.2010.10.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Revised: 10/19/2010] [Accepted: 10/24/2010] [Indexed: 11/26/2022]
Abstract
As the principal component of high-density lipoprotein (HDL), apolipoprotein (apo) A-I plays essential roles in lipid transport and metabolism. Because of its intrinsic conformational plasticity and flexibility, the molecular details of the tertiary structure of lipid-free apoA-I have not been fully elucidated. Previously, we demonstrated that the stability of the N-terminal helix bundle structure is modulated by proline substitution at the most hydrophobic region (residues around Y18) in the N-terminal domain. Here we examine the effect of proline substitution at S55 located in another relatively hydrophobic region compared to most of the helix bundle domain to elucidate the influences on the helix bundle structure and lipid interaction. Fluorescence measurements revealed that the S55P mutation had a modest effect on the stability of the bundle structure, indicating that residues around S55 are not pivotally involved in the helix bundle formation, in contrast to the insertion of proline at position 18. Although truncation of the C-terminal domain (Δ190-243) diminishes the lipid binding of apoA-I molecule, the mutation S55P in addition to the C-terminal truncation (S55P/Δ190-243) restored the lipid binding, suggesting that the S55P mutation causes a partial unfolding of the helix bundle to facilitate lipid binding. Furthermore, additional proline substitution at Y18 (Y18P/S55P/Δ190-243), which leads to a drastic unfolding of the helix bundle structure, yielded a greater lipid binding ability. Thus, proline substitutions in the N-terminal domain of apoA-I that destabilized the helix bundle promoted lipid solubilization. These results suggest that not only the hydrophobic C-terminal helical domain but also the stability of the N-terminal helix bundle in apoA-I are important modulators of the spontaneous solubilization of membrane lipids by apoA-I, a process that leads to the generation of nascent HDL particles.
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Affiliation(s)
- Masafumi Tanaka
- Department of Biophysical Chemistry, Kobe Pharmaceutical University, Kobe 658-8558, Japan.
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27
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Haas MJ, Mooradian AD. Therapeutic Interventions to Enhance Apolipoprotein A-I-Mediated Cardioprotection. Drugs 2010; 70:805-21. [DOI: 10.2165/11535410-000000000-00000] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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28
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Vergeer M, Holleboom AG, Kastelein JJP, Kuivenhoven JA. The HDL hypothesis: does high-density lipoprotein protect from atherosclerosis? J Lipid Res 2010; 51:2058-73. [PMID: 20371550 DOI: 10.1194/jlr.r001610] [Citation(s) in RCA: 146] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
There is unequivocal evidence of an inverse association between plasma high-density lipoprotein (HDL) cholesterol concentrations and the risk of cardiovascular disease, a finding that has led to the hypothesis that HDL protects from atherosclerosis. This review details the experimental evidence for this "HDL hypothesis". In vitro studies suggest that HDL has a wide range of anti-atherogenic properties but validation of these functions in humans is absent to date. A significant number of animal studies and clinical trials support an atheroprotective role for HDL; however, most of these findings were obtained in the context of marked changes in other plasma lipids. Finally, genetic studies in humans have not provided convincing evidence that HDL genes modulate cardiovascular risk. Thus, despite a wealth of information on this intriguing lipoprotein, future research remains essential to prove the HDL hypothesis correct.
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Affiliation(s)
- Menno Vergeer
- Department of Vascular Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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29
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Fu Y. Rate-limiting factors of cholesterol efflux in reverse cholesterol transport: Acceptors and donors. Clin Exp Pharmacol Physiol 2010; 37:703-9. [DOI: 10.1111/j.1440-1681.2010.05386.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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30
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Recombinant apolipoprotein A-I Milano rapidly reverses aortic valve stenosis and decreases leaflet inflammation in an experimental rabbit model. Eur Heart J 2010; 31:2049-57. [DOI: 10.1093/eurheartj/ehq064] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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31
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Murphy AJ, Chin-Dusting J, Sviridov D. Reconstituted HDL: a therapy for atherosclerosis and beyond. ACTA ACUST UNITED AC 2009. [DOI: 10.2217/clp.09.68] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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32
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Alexander ET, Weibel GL, Joshi MR, Vedhachalam C, de la Llera-Moya M, Rothblat GH, Phillips MC, Rader DJ. Macrophage reverse cholesterol transport in mice expressing ApoA-I Milano. Arterioscler Thromb Vasc Biol 2009; 29:1496-501. [PMID: 19661486 PMCID: PMC2943867 DOI: 10.1161/atvbaha.109.191379] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE To compare the abilities of human wild-type apoA-I (WT apoA-I) and human apoA-I(Milano) (apoA-I(M)) to promote macrophage reverse cholesterol transport (RCT) in apoA-I-null mice infected with adeno-associated virus (AAV) expressing either WT apoA-I or apoA-I(M). METHODS AND RESULTS WT apoA-I- or apoA-I(M)-expressing mice were intraperitoneally injected with [H(3)]cholesterol-labeled J774 mouse macrophages. After 48 hours, no significant difference was detected in the amount of cholesterol removed from the macrophages and deposited in the feces via the RCT pathway between the WT apoA-I and apoA-I(M) groups. Analysis of the individual components of the RCT pathway demonstrated that the apoA-I(M)-expressing mice promoted ATP-binding cassette transporter A1 (ABCA1)-mediated cholesterol efflux as efficiently as WT apoA-I but that apoA-I(M) had a reduced ability to promote cholesterol esterification via lecithin cholesterol-acyltransferase (LCAT). This resulted in reduced cholesteryl ester (CE) and increased free cholesterol (FC) levels in the plasma of mice expressing apoA-I(M) compared to WT apoA-I. These differences did not affect the rate of delivery of labeled cholesterol to the liver via SR-BI-mediated selective uptake or its subsequent excretion in the feces. CONCLUSIONS Within the limits of the in vivo assay, WT apoA-I and apoA-I(M) are equally efficient at promoting macrophage RCT, suggesting that if apoA-I(M) is more atheroprotective than WT apoA-I it is not attributable to an enhancement of macrophage RCT.
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Affiliation(s)
- Eric T Alexander
- Lipid Research Group, Children's Hospital of Philadelphia, Philadelphia, PA, USA
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Daniels TF, Killinger KM, Michal JJ, Wright RW, Jiang Z. Lipoproteins, cholesterol homeostasis and cardiac health. Int J Biol Sci 2009; 5:474-88. [PMID: 19584955 PMCID: PMC2706428 DOI: 10.7150/ijbs.5.474] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Accepted: 06/19/2009] [Indexed: 12/22/2022] Open
Abstract
Cholesterol is an essential substance involved in many functions, such as maintaining cell membranes, manufacturing vitamin D on surface of the skin, producing hormones, and possibly helping cell connections in the brain. When cholesterol levels rise in the blood, they can, however, have dangerous consequences. In particular, cholesterol has generated considerable notoriety for its causative role in atherosclerosis, the leading cause of death in developed countries around the world. Homeostasis of cholesterol is centered on the metabolism of lipoproteins, which mediate transport of the lipid to and from tissues. As a synopsis of the major events and proteins that manage lipoprotein homeostasis, this review contributes to the substantial attention that has recently been directed to this area. Despite intense scrutiny, the majority of phenotypic variation in total cholesterol and related traits eludes explanation by current genetic knowledge. This is somewhat disappointing considering heritability estimates have established these traits as highly genetic. Thus, the continued search for candidate genes, mutations, and mechanisms is vital to our understanding of heart disease at the molecular level. Furthermore, as marker development continues to predict risk of vascular illness, this knowledge has the potential to revolutionize treatment of this leading human disease.
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Affiliation(s)
- Tyler F Daniels
- Department of Animal Sciences, Washington State University, Pullman, WA 99164-6351, USA
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Alexander ET, Tanaka M, Kono M, Saito H, Rader DJ, Phillips MC. Structural and functional consequences of the Milano mutation (R173C) in human apolipoprotein A-I. J Lipid Res 2009; 50:1409-19. [PMID: 19318685 DOI: 10.1194/jlr.m800578-jlr200] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Carriers of the apolipoprotein A-I(Milano) (apoA-I(M)) variant, R173C, have reduced levels of plasma HDL but no increase in cardiovascular disease. Despite intensive study, it is not clear whether the removal of the arginine or the introduction of the cysteine is responsible for this altered functionality. We investigated this question using two engineered variations of the apoA-I(M) mutation: R173S apoA-I, similar to apoA-I(M) but incapable of forming a disulfide bond, and R173K apoA-I, a conservative mutation. Characterization of the lipid-free proteins showed that the order of stability was wild type approximately R173K>R173S>R173C. Compared with wild-type apoA-I, apoA-I(M) had a lower affinity for lipids, while R173S apoA-I displayed intermediate affinity. The in vivo effects of the apoA-I variants were measured by injecting apoA-I-expressing adeno-associated virus into apoA-I-null mice. Mice that expressed the R173S variant again showed an intermediate phenotype. Thus, both the loss of the arginine and its replacement by a cysteine contribute to the altered properties of apoA-I(M). The arginine is potentially involved in an intrahelical salt bridge with E169 that is disrupted by the loss of the positively charged arginine and repelled by the cysteine, destabilizing the helix bundle domain in the apoA-I molecule and modifying its lipid binding characteristics.
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Affiliation(s)
- Eric T Alexander
- Gastroenterology/Nutrition/Hepatology Division, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-4318, USA
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35
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Cimmino G, Ibanez B, Vilahur G, Speidl WS, Fuster V, Badimon L, Badimon JJ. Up-regulation of reverse cholesterol transport key players and rescue from global inflammation by ApoA-I(Milano). J Cell Mol Med 2008; 13:3226-35. [PMID: 19120689 PMCID: PMC4516480 DOI: 10.1111/j.1582-4934.2008.00614.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Recombinant-ApoA-IM (rApoA-IM) administration has been shown to regress and stabilize atherosclerotic plaques. However, the mechanisms responsible for these beneficial effects are not fully understood. The aims of the present study were to define whether the benefits of rApoA-IM treatment were mediated via an enhanced reverse cholesterol transport (RCT) and/or anti-inflammation-related mechanisms. Advanced aortic lesions were induced in New Zealand White rabbits (n= 16). Animals were randomized to placebo or rApoA-IM (rApoA-IM/phospholipids; ETC-216), two infusions 4 days apart. Four days after last dose, aortas and livers were processed for cholesterol content, expression of RCT-related receptors (ATP-binding cassette A-1 [ABCA-1] and scavenger receptor BI [SR-BI]), and inflammation-related markers (inducible nitric oxide synthase [iNOS] and capase-3). Oxidative stress was assessed in the vessel wall and in plasma. rApoA-IM administration resulted in a significant reduction in the hepatic and aortic cholesterol content without differences in plasma levels. This effect was associated with an up-regulation of vessel wall ABCA-1, as well as a hepatic and arterial-wall SR-BI up-regulation. Systemic and atherosclerotic-plaque inflammation markers were significantly reduced by the rApoA-IM administration, as demonstrated by a reduction in circulating oxidative stress markers and prostaglandin F1-α levels, and the down-regulation of the iNOS and caspase 3 in the aortic lesions. rApoA-IM up-regulated the ABCA-1 and SR-BI levels to a greater extent than the wild-type form of apoA-I in in vitro studies done with lipid-rich macrophages. Our data suggest that rApoA-IM administration enhances RCT and induces a ‘rescue’ from the global inflammatory status associated with atherosclerotic disease. The Milano form of apoA-I seems to be more efficient in RCT than the apoA-I wild-type.
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Affiliation(s)
- Giovanni Cimmino
- Cardiovascular Biology Research Laboratory, Cardiovascular Institute, Mount Sinai School of Medicine, New York, NY, USA
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Feng Y, Van Craeyveld E, Jacobs F, Lievens J, Snoeys J, De Geest B. Wild-type apo A-I and apo A-I(Milano) gene transfer reduce native and transplant arteriosclerosis to a similar extent. J Mol Med (Berl) 2008; 87:287-97. [PMID: 19066833 DOI: 10.1007/s00109-008-0427-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 10/29/2008] [Accepted: 11/27/2008] [Indexed: 10/21/2022]
Abstract
Apolipoprotein (apo) A-I(Milano) is an apo A-I mutant characterized by a cysteine for arginine substitution at position 173. Apo A-I(Milano) carriers have much less atherosclerosis than expected from their low plasma high-density lipoprotein cholesterol levels, suggesting that this mutant may have superior atheroprotective properties. Here, we compare the effect of hepatocyte-directed gene transfer of wild-type human apo A-I and human apo A-I(Milano) on endothelial progenitor cell (EPC) biology and on the progression of native atherosclerosis and allograft vasculopathy in C57BL/6 apo E(-/-) mice. Human apo A-I and apo A-I(Milano) transfer resulted in an equivalent increase of EPC number and function as well as EPC incorporation and endothelial regeneration in allografts and inhibited the progression of native atherosclerosis and allograft vasculopathy to a similar extent. In conclusion, the current head-to-head comparison indicates that human apo A-I(Milano) transfer is not superior compared to wild-type human apo A-I transfer.
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Affiliation(s)
- Yingmei Feng
- Center for Molecular and Vascular Biology, Campus Gasthuisberg, University of Leuven, Herestraat, Belgium
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Mythreye K, Satterwhite LL, Davidson WS, Goldschmidt-Clermont PJ. ApoA-I induced CD31 in bone marrow-derived vascular progenitor cells increases adhesion: implications for vascular repair. Biochim Biophys Acta Mol Cell Biol Lipids 2008; 1781:703-9. [PMID: 18775511 DOI: 10.1016/j.bbalip.2008.08.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Revised: 07/18/2008] [Accepted: 08/04/2008] [Indexed: 12/13/2022]
Abstract
Transgenic over expression of apolipoprotein A-I (ApoA-I) the major structural apolipoprotein of HDL appears to convey the most consistent and strongest anti atherogenic effect observed in animal models so far. We tested the hypothesis that ApoA-I mediates its cardio protective effects additionally through ApoA-I induced differentiation of bone marrow-derived progenitor cells in vitro. This study demonstrates that lineage negative bone marrow cells (lin(-) BMCs) alter and differentiate in response to free ApoA-I. We find that lin(-) BMCs in culture treated with recombinant free ApoA-I at a concentration of 0.4 microM are twice as large in size and have altered cell morphology compared to untreated cells; untreated cells retain the original spheroid morphology. Further, the total number of CD31 positive cells in the ApoA-I treated population consistently increased by two fold. This phenotype was significantly reduced in untreated cells and points towards a novel ApoA-I dependent differentiation. A protein lacking its best lipid-binding region (ApoA-I Delta 10) did not stimulate any changes in the lin(-)BMCs indicating that ApoA-I may mediate its effects by regulating cholesterol efflux. The increased CD31 correlates with an increased ability of the lin(-) BMCs to adhere to both fibronectin and mouse brain endothelial cells. Our results provide the first evidence that exogenous free ApoA-I has the capacity to change the characteristics of progenitor cell populations and suggests a novel mechanism by which HDL may mediate its cardiovascular benefits.
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Affiliation(s)
- Karthikeyan Mythreye
- Department of Medicine, Duke University Medical Center, 209 MSRB1 Research Drive, Durham, NC 27710, USA.
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Tall AR. Cholesterol efflux pathways and other potential mechanisms involved in the athero-protective effect of high density lipoproteins. J Intern Med 2008; 263:256-73. [PMID: 18271871 DOI: 10.1111/j.1365-2796.2007.01898.x] [Citation(s) in RCA: 308] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Plasma high density lipoprotein (HDL) levels bear a strong independent inverse relationship with atherosclerotic cardiovascular disease. Although HDL has anti-oxidant, anti-inflammatory, vasodilating and anti-thrombotic properties, the central anti-atherogenic activity of HDL is likely to be its ability to remove cholesterol and oxysterols from macrophage foam cells, smooth muscle cells and endothelial cells in the arterial wall. To some extent, the pleotropic athero-protective properties of HDL may be related to its ability to promote sterol and oxysterol efflux from arterial wall cells, as well as to detoxify oxidized phospholipids. In cholesterol-loaded macrophages, activation of liver X receptors (LXRs) leads to increased expression of adenosine triphosphate (ATP) binding cassetter transporter (ABCA1), ATP binding cassetter transporter gene (ABCG1) and apoE and promotes cholesterol efflux. ABCA1 stimulates cholesterol efflux to lipid-poor apolipoproteins, whilst ABCG1 promotes efflux of cholesterol and oxysterols to HDL. Despite some recent setbacks in the clinical arena, there is still intense interest in therapeutically targeting HDL and macrophage cholesterol efflux pathways, via treatments with niacin, cholesterol ester transfer protein inhibitors, LXR activators and infusions of apoA-1, phospholipids and peptides.
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Affiliation(s)
- A R Tall
- Division of Molecular Medicine, Department of Medicine, Columbia University, NY, USA
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Abstract
The dramatic failure of clinical trials evaluating the cholesterol ester transfer protein inhibitor torcetrapib has led to considerable doubt about the value of raising high-density lipoprotein cholesterol (HDL-C) as a treatment for cardiovascular disease. These results have underscored the intricacy of HDL metabolism, with functional quality perhaps being a more important consideration than the circulating quantity of HDL. As a result, HDL-based therapeutics that maintain or enhance HDL functionality warrant closer investigation. In this article, we review the complexity of HDL metabolism, discuss clinical-trial data for HDL-raising agents, including possible reasons for the failure of torcetrapib, and consider the potential for future HDL-based therapies.
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Duong PT, Weibel GL, Lund-Katz S, Rothblat GH, Phillips MC. Characterization and properties of pre beta-HDL particles formed by ABCA1-mediated cellular lipid efflux to apoA-I. J Lipid Res 2008; 49:1006-14. [PMID: 18252847 DOI: 10.1194/jlr.m700506-jlr200] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The contribution of ABCA1-mediated efflux of cellular phospholipid (PL) and cholesterol to human apolipoprotein A-I (apoA-I) to the formation of pre beta 1-HDL (or lipid-poor apoA-I) is not well defined. To explore this issue, we characterized the nascent HDL particles formed when lipid-free apoA-I was incubated with fibroblasts in which expression of the ABCA1 was upregulated. After a 2 h incubation, the extracellular medium contained small apoA-I/PL particles (pre beta 1-HDL; diameter = 7.5 +/- 0.4 nm). The pre beta 1-HDL (or lipid-poor apoA-I) particles contained a single apoA-I molecule and three to four PL molecules and one to two cholesterol molecules. An apoA-I variant lacking the C-terminal alpha-helix did not form such particles when incubated with the cell, indicating that this helix is critical for the formation of lipid-poor apoA-I particles. These pre beta 1-HDL particles were as effective as lipid-free apoA-I molecules in mediating both the efflux of cellular lipids via ABCA1 and the formation of larger, discoidal HDL particles. In conclusion, pre beta 1-HDL is both a product and a substrate in the ABCA1-mediated reaction to efflux cellular PL and cholesterol to apoA-I. A monomeric apoA-I molecule associated with three to four PL molecules (i.e., lipid-poor apoA-I) has similar properties to the lipid-free apoA-I molecule.
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Affiliation(s)
- Phu T Duong
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-4318, USA
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