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Lin P, Ji HH, Li YJ, Guo SD. Macrophage Plasticity and Atherosclerosis Therapy. Front Mol Biosci 2021; 8:679797. [PMID: 34026849 PMCID: PMC8138136 DOI: 10.3389/fmolb.2021.679797] [Citation(s) in RCA: 85] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 04/12/2021] [Indexed: 12/15/2022] Open
Abstract
Atherosclerosis is a chronic disease starting with the entry of monocytes into the subendothelium and the subsequent differentiation into macrophages. Macrophages are the major immune cells in atherosclerotic plaques and are involved in the dynamic progression of atherosclerotic plaques. The biological properties of atherosclerotic plaque macrophages determine lesion size, composition, and stability. The heterogenicity and plasticity of atherosclerotic macrophages have been a hotspot in recent years. Studies demonstrated that lipids, cytokines, chemokines, and other molecules in the atherosclerotic plaque microenvironment regulate macrophage phenotype, contributing to the switch of macrophages toward a pro- or anti-atherosclerosis state. Of note, M1/M2 classification is oversimplified and only represent two extreme states of macrophages. Moreover, M2 macrophages in atherosclerosis are not always protective. Understanding the phenotypic diversity and functions of macrophages can disclose their roles in atherosclerotic plaques. Given that lipid-lowering therapy cannot completely retard the progression of atherosclerosis, macrophages with high heterogeneity and plasticity raise the hope for atherosclerosis regression. This review will focus on the macrophage phenotypic diversity, its role in the progression of the dynamic atherosclerotic plaque, and finally discuss the possibility of treating atherosclerosis by targeting macrophage microenvironment.
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Affiliation(s)
- Ping Lin
- Institute of Lipid Metabolism and Atherosclerosis, Innovative Drug Research Centre, School of Pharmacy, Weifang Medical University, Weifang, China
| | - Hong-Hai Ji
- Institute of Lipid Metabolism and Atherosclerosis, Innovative Drug Research Centre, School of Pharmacy, Weifang Medical University, Weifang, China
| | - Yan-Jie Li
- Institute of Lipid Metabolism and Atherosclerosis, Innovative Drug Research Centre, School of Pharmacy, Weifang Medical University, Weifang, China
| | - Shou-Dong Guo
- Institute of Lipid Metabolism and Atherosclerosis, Innovative Drug Research Centre, School of Pharmacy, Weifang Medical University, Weifang, China
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Gonen A, Miller YI. From Inert Storage to Biological Activity-In Search of Identity for Oxidized Cholesteryl Esters. Front Endocrinol (Lausanne) 2020; 11:602252. [PMID: 33329402 PMCID: PMC7715012 DOI: 10.3389/fendo.2020.602252] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 10/23/2020] [Indexed: 12/31/2022] Open
Abstract
Esterification of cholesterol is a universal mechanism to store and transport large quantities of cholesterol between organs and tissues and to avoid toxicity of the excess of cellular cholesterol. Intended for transport and storage and thus to be inert, cholesteryl esters (CEs) reside in hydrophobic cores of circulating lipoproteins and intracellular lipid droplets. However, the inert identity of CEs is dramatically changed if cholesterol is esterified to a polyunsaturated fatty acid and subjected to oxidative modification. Post-synthetic, or epilipidomic, oxidative modifications of CEs are mediated by specialized enzymes, chief among them are lipoxygenases, and by free radical oxidation. The complex repertoire of oxidized CE (OxCE) products exhibit various, context-dependent biological activities, surveyed in this review. Oxidized fatty acyl chains in OxCE can be hydrolyzed and re-esterified, thus seeding oxidized moieties into phospholipids (PLs), with OxPLs having different from OxCEs biological activities. Technological advances in mass spectrometry and the development of new anti-OxCE antibodies make it possible to validate the presence and quantify the levels of OxCEs in human atherosclerotic lesions and plasma. The article discusses the prospects of measuring OxCE levels in plasma as a novel biomarker assay to evaluate risk of developing cardiovascular disease and efficacy of treatment.
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Gibson MS, Domingues N, Vieira OV. Lipid and Non-lipid Factors Affecting Macrophage Dysfunction and Inflammation in Atherosclerosis. Front Physiol 2018; 9:654. [PMID: 29997514 PMCID: PMC6029489 DOI: 10.3389/fphys.2018.00654] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 05/14/2018] [Indexed: 01/08/2023] Open
Abstract
Atherosclerosis is a chronic inflammatory disease and a leading cause of human mortality. The lesional microenvironment contains a complex accumulation of variably oxidized lipids and cytokines. Infiltrating monocytes become polarized in response to these stimuli, resulting in a broad spectrum of macrophage phenotypes. The extent of lipid loading in macrophages influences their phenotype and consequently their inflammatory status. In response to excess atherogenic ligands, many normal cell processes become aberrant following a loss of homeostasis. This can have a direct impact upon the inflammatory response, and conversely inflammation can lead to cell dysfunction. Clear evidence for this exists in the lysosomes, endoplasmic reticulum and mitochondria of atherosclerotic macrophages, the principal lesional cell type. Furthermore, several intrinsic cell processes become dysregulated under lipidotic conditions. Therapeutic strategies aimed at restoring cell function under disease conditions are an ongoing coveted aim. Macrophages play a central role in promoting lesional inflammation, with plaque progression and stability being directly proportional to macrophage abundance. Understanding how mixtures or individual lipid species regulate macrophage biology is therefore a major area of atherosclerosis research. In this review, we will discuss how the myriad of lipid and lipoprotein classes and products used to model atherogenic, proinflammatory immune responses has facilitated a greater understanding of some of the intricacies of chronic inflammation and cell function. Despite this, lipid oxidation produces a complex mixture of products and with no single or standard method of derivatization, there exists some variation in the reported effects of certain oxidized lipids. Likewise, differences in the methods used to generate macrophages in vitro may also lead to variable responses when apparently identical lipid ligands are used. Consequently, the complexity of reported macrophage phenotypes has implications for our understanding of the metabolic pathways, processes and shifts underpinning their activation and inflammatory status. Using oxidized low density lipoproteins and its oxidized cholesteryl esters and phospholipid constituents to stimulate macrophage has been hugely valuable, however there is now an argument that only working with low complexity lipid species can deliver the most useful information to guide therapies aimed at controlling atherosclerosis and cardiovascular complications.
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Affiliation(s)
- Mark S Gibson
- Lysosomes in Chronic Human Pathologies and Infection, Faculdade de Ciências Médicas, Centro de Estudos de Doenças Crónicas, NOVA Medical School, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Neuza Domingues
- Lysosomes in Chronic Human Pathologies and Infection, Faculdade de Ciências Médicas, Centro de Estudos de Doenças Crónicas, NOVA Medical School, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Otilia V Vieira
- Lysosomes in Chronic Human Pathologies and Infection, Faculdade de Ciências Médicas, Centro de Estudos de Doenças Crónicas, NOVA Medical School, Universidade NOVA de Lisboa, Lisbon, Portugal
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Choi SH, Sviridov D, Miller YI. Oxidized cholesteryl esters and inflammation. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:393-397. [PMID: 27368140 DOI: 10.1016/j.bbalip.2016.06.020] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 06/08/2016] [Accepted: 06/24/2016] [Indexed: 11/30/2022]
Abstract
The oxidation hypothesis of atherosclerosis proposes that oxidized LDL is a major causative factor in the development of atherosclerosis. Although this hypothesis has received strong mechanistic support and many animal studies demonstrated profound atheroprotective effects of antioxidants, which reduce LDL oxidation, the results of human clinical trials with antioxidants were mainly negative, except in selected groups of patients with clearly increased systemic oxidative stress. We propose that even if reducing lipoprotein oxidation in humans might be difficult to achieve, deeper understanding of mechanisms by which oxidized LDL promotes atherosclerosis and targeting these specific mechanisms will offer novel approaches to treatment of cardiovascular disease. In this review article, we focus on oxidized cholesteryl esters (OxCE), which are a major component of minimally and extensively oxidized LDL and of human atherosclerotic lesions. OxCE and OxCE-protein covalent adducts induce profound biological effects. Among these effects, OxCE activate macrophages via toll-like receptor-4 (TLR4) and spleen tyrosine kinase and induce macropinocytosis resulting in lipid accumulation, generation of reactive oxygen species and secretion of inflammatory cytokines. Specific inhibition of OxCE-induced TLR4 activation, as well as blocking other inflammatory effects of OxCE, may offer novel treatments of atherosclerosis and cardiovascular disease. This article is part of a Special Issue entitled: Lipid modification and lipid peroxidation products in innate immunity and inflammation edited by Christoph J. Binder.
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Affiliation(s)
- Soo-Ho Choi
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Dmitri Sviridov
- Baker IDI Heart and Diabetes Institute, Melbourne, VIC 3004, Australia
| | - Yury I Miller
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
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Poli G. A new biochemical effect of 4-hydroxynonenal: downregulation of TGFβ-dependent elastogenesis. Free Radic Biol Med 2014; 71:437-438. [PMID: 24637262 DOI: 10.1016/j.freeradbiomed.2014.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 03/10/2014] [Indexed: 11/20/2022]
Affiliation(s)
- Giuseppe Poli
- Department of Clinical and Biological Sciences, University of Torino, 10043 Orbassano (Torino), Italy.
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Huh GW, Park JH, Kang JH, Jeong TS, Kang HC, Baek NI. Flavonoids from Lindera glauca Blume as low-density lipoprotein oxidation inhibitors. Nat Prod Res 2014; 28:831-4. [DOI: 10.1080/14786419.2013.879583] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Gyu-Won Huh
- The Graduate School of Biotechnology, Institute of Life Sciences & Resources, Kyung Hee University, Yongin 446-701, Republic of Korea
| | - Ji-Hae Park
- The Graduate School of Biotechnology, Institute of Life Sciences & Resources, Kyung Hee University, Yongin 446-701, Republic of Korea
| | - Ji-Hyun Kang
- National Research Laboratory of Lipid Metabolism & Atherosclerosis, KRIBB, Daejeon 305-806, Republic of Korea
| | - Tae-Sook Jeong
- National Research Laboratory of Lipid Metabolism & Atherosclerosis, KRIBB, Daejeon 305-806, Republic of Korea
| | | | - Nam-In Baek
- The Graduate School of Biotechnology, Institute of Life Sciences & Resources, Kyung Hee University, Yongin 446-701, Republic of Korea
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Leonarduzzi G, Gamba P, Gargiulo S, Biasi F, Poli G. Inflammation-related gene expression by lipid oxidation-derived products in the progression of atherosclerosis. Free Radic Biol Med 2012; 52:19-34. [PMID: 22037514 DOI: 10.1016/j.freeradbiomed.2011.09.031] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 09/16/2011] [Accepted: 09/24/2011] [Indexed: 12/31/2022]
Abstract
Vascular areas of atherosclerotic development persist in a state of inflammation, and any further inflammatory stimulus in the subintimal area elicits a proatherogenic response; this alters the behavior of the artery wall cells and recruits further inflammatory cells. In association with the inflammatory response, oxidative events are also involved in the development of atherosclerotic plaques. It is now unanimously recognized that lipid oxidation-derived products are key players in the initiation and progression of atherosclerotic lesions. Oxidized lipids, derived from oxidatively modified low-density lipoproteins (LDLs), which accumulate in the intima, strongly modulate inflammation-related gene expression, through involvement of various signaling pathways. In addition, considerable evidence supports a proatherogenic role of a large group of potent bioactive lipids called eicosanoids, which derive from oxidation of arachidonic acid, a component of membrane phospholipids. Of note, LDL lipid oxidation products might regulate eicosanoid production, modulating the enzymatic degradation of arachidonic acid by cyclooxygenases and lipoxygenases; these enzymes might also directly contribute to LDL oxidation. This review provides a comprehensive overview of current knowledge on signal transduction pathways and inflammatory gene expression, modulated by lipid oxidation-derived products, in the progression of atherosclerosis.
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Levitan I, Volkov S, Subbaiah PV. Oxidized LDL: diversity, patterns of recognition, and pathophysiology. Antioxid Redox Signal 2010; 13:39-75. [PMID: 19888833 PMCID: PMC2877120 DOI: 10.1089/ars.2009.2733] [Citation(s) in RCA: 308] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Revised: 10/09/2009] [Accepted: 11/02/2009] [Indexed: 02/06/2023]
Abstract
Oxidative modification of LDL is known to elicit an array of pro-atherogenic responses, but it is generally underappreciated that oxidized LDL (OxLDL) exists in multiple forms, characterized by different degrees of oxidation and different mixtures of bioactive components. The variable effects of OxLDL reported in the literature can be attributed in large part to the heterogeneous nature of the preparations employed. In this review, we first describe the various subclasses and molecular composition of OxLDL, including the variety of minimally modified LDL preparations. We then describe multiple receptors that recognize various species of OxLDL and discuss the mechanisms responsible for the recognition by specific receptors. Furthermore, we discuss the contentious issues such as the nature of OxLDL in vivo and the physiological oxidizing agents, whether oxidation of LDL is a prerequisite for atherogenesis, whether OxLDL is the major source of lipids in foam cells, whether in some cases it actually induces cholesterol depletion, and finally the Janus-like nature of OxLDL in having both pro- and anti-inflammatory effects. Lastly, we extend our review to discuss the role of LDL oxidation in diseases other than atherosclerosis, including diabetes mellitus, and several autoimmune diseases, such as lupus erythematosus, anti-phospholipid syndrome, and rheumatoid arthritis.
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Affiliation(s)
- Irena Levitan
- Section of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
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