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Munno M, Mallia A, Greco A, Modafferi G, Banfi C, Eligini S. Radical Oxygen Species, Oxidized Low-Density Lipoproteins, and Lectin-like Oxidized Low-Density Lipoprotein Receptor 1: A Vicious Circle in Atherosclerotic Process. Antioxidants (Basel) 2024; 13:583. [PMID: 38790688 PMCID: PMC11118168 DOI: 10.3390/antiox13050583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 05/06/2024] [Accepted: 05/07/2024] [Indexed: 05/26/2024] Open
Abstract
Atherosclerosis is a complex condition that involves the accumulation of lipids and subsequent plaque formation in the arterial intima. There are various stimuli, cellular receptors, and pathways involved in this process, but oxidative modifications of low-density lipoprotein (ox-LDL) are particularly important in the onset and progression of atherosclerosis. Ox-LDLs promote foam-cell formation, activate proinflammatory pathways, and induce smooth-muscle-cell migration, apoptosis, and cell death. One of the major receptors for ox-LDL is LOX-1, which is upregulated in several cardiovascular diseases, including atherosclerosis. LOX-1 activation in endothelial cells promotes endothelial dysfunction and induces pro-atherogenic signaling, leading to plaque formation. The binding of ox-LDLs to LOX-1 increases the generation of reactive oxygen species (ROS), which can induce LOX-1 expression and oxidize LDLs, contributing to ox-LDL generation and further upregulating LOX-1 expression. This creates a vicious circle that is amplified in pathological conditions characterized by high plasma levels of LDLs. Although LOX-1 has harmful effects, the clinical significance of inhibiting this protein remains unclear. Further studies both in vitro and in vivo are needed to determine whether LOX-1 inhibition could be a potential therapeutic target to counteract the atherosclerotic process.
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Affiliation(s)
- Marco Munno
- Unit of Functional Proteomics, Metabolomics and Network Analysis, Centro Cardiologico Monzino, 20138 Milan, Italy; (M.M.); (A.M.); (A.G.); (G.M.); (S.E.)
| | - Alice Mallia
- Unit of Functional Proteomics, Metabolomics and Network Analysis, Centro Cardiologico Monzino, 20138 Milan, Italy; (M.M.); (A.M.); (A.G.); (G.M.); (S.E.)
- Dipartimento di Biologia e Biotecnologie “Lazzaro Spallanzani”, Università di Pavia, 27100 Pavia, Italy
| | - Arianna Greco
- Unit of Functional Proteomics, Metabolomics and Network Analysis, Centro Cardiologico Monzino, 20138 Milan, Italy; (M.M.); (A.M.); (A.G.); (G.M.); (S.E.)
| | - Gloria Modafferi
- Unit of Functional Proteomics, Metabolomics and Network Analysis, Centro Cardiologico Monzino, 20138 Milan, Italy; (M.M.); (A.M.); (A.G.); (G.M.); (S.E.)
| | - Cristina Banfi
- Unit of Functional Proteomics, Metabolomics and Network Analysis, Centro Cardiologico Monzino, 20138 Milan, Italy; (M.M.); (A.M.); (A.G.); (G.M.); (S.E.)
| | - Sonia Eligini
- Unit of Functional Proteomics, Metabolomics and Network Analysis, Centro Cardiologico Monzino, 20138 Milan, Italy; (M.M.); (A.M.); (A.G.); (G.M.); (S.E.)
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Bagheri B, Khatibiyan Feyzabadi Z, Nouri A, Azadfallah A, Mahdizade Ari M, Hemmati M, Darban M, Alavi Toosi P, Banihashemian SZ. Atherosclerosis and Toll-Like Receptor4 (TLR4), Lectin-Like Oxidized Low-Density Lipoprotein-1 (LOX-1), and Proprotein Convertase Subtilisin/Kexin Type9 (PCSK9). Mediators Inflamm 2024; 2024:5830491. [PMID: 38445291 PMCID: PMC10914434 DOI: 10.1155/2024/5830491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 01/31/2024] [Accepted: 02/16/2024] [Indexed: 03/07/2024] Open
Abstract
Atherosclerosis is a leading cause of death in the world. A significant body of evidence suggests that inflammation and various players are implicated and have pivotal roles in the formation of atherosclerotic plaques. Toll-like receptor 4 (TLR4) is linked with different stages of atherosclerosis. This receptor is highly expressed in the endothelial cells (ECs) and atherosclerotic plaques. TLR4 activation can lead to the production of inflammatory cytokines and related responses. Lectin-like oxidized low-density lipoprotein-1 (LOX-1), an integral membrane glycoprotein with widespread expression on the ECs, is involved in atherosclerosis and has some common pathways with TLR4 in atherosclerotic lesions. In addition, proprotein convertase subtilisin/kexin type9 (PCSK9), which is a regulatory enzyme with different roles in cholesterol uptake, is implicated in atherosclerosis. At present, TLR4, PCSK9, and LOX-1 are increasingly acknowledged as key players in the pathogenesis of atherosclerotic cardiovascular diseases. Herein, we presented the current evidence on the structure, functions, and roles of TLR4, PCSK9, and LOX-1 in atherosclerosis.
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Affiliation(s)
- Bahador Bagheri
- Cancer Research Center, Semnan University of Medical Sciences, Semnan, Iran
- Center for Molecular Cardiology, University of Zurich, Schlieren, Switzerland
| | | | - Ahmad Nouri
- Student Research Committee, Faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran
| | - Ali Azadfallah
- Student Research Committee, Faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran
| | - Mahyar Mahdizade Ari
- Student Research Committee, Faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran
| | - Maral Hemmati
- Cancer Research Center, Semnan University of Medical Sciences, Semnan, Iran
| | - Mahboubeh Darban
- Department of Internal Medicine, Kowsar Hospital, Semnan University of Medical Sciences, Semnan, Iran
| | - Parisa Alavi Toosi
- Student Research Committee, Faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran
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Slavetinsky J, Lehmann E, Slavetinsky C, Gritsch L, van Dalen R, Kretschmer D, Bleul L, Wolz C, Weidenmaier C, Peschel A. Wall Teichoic Acid Mediates Staphylococcus aureus Binding to Endothelial Cells via the Scavenger Receptor LOX-1. ACS Infect Dis 2023; 9:2133-2140. [PMID: 37910786 DOI: 10.1021/acsinfecdis.3c00252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
The success of Staphylococcus aureus as a major cause for endovascular infections depends on effective interactions with blood-vessel walls. We have previously shown that S. aureus uses its wall teichoic acid (WTA), a surface glycopolymer, to attach to endothelial cells. However, the endothelial WTA receptor remained unknown. We show here that the endothelial oxidized low-density lipoprotein receptor 1 (LOX-1) interacts with S. aureus WTA and permits effective binding of S. aureus to human endothelial cells. Purified LOX-1 bound to isolated S. aureus WTA. Ectopic LOX-1 expression led to increased binding of S. aureus wild type but not of a WTA-deficient mutant to a cell line, and LOX-1 blockage prevented S. aureus binding to endothelial cells. Moreover, WTA and LOX-1 expression levels correlated with the efficacy of the S. aureus-endothelial interaction. Thus, LOX-1 is an endothelial ligand for S. aureus, whose blockage may help to prevent or treat severe endovascular infections.
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Affiliation(s)
- Jessica Slavetinsky
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen72076, Germany
- Cluster of Excellence EXC 2124 "Controlling Microbes to Fight Infections", University of Tübingen, Tübingen 72076, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen 72076 , Germany
| | - Esther Lehmann
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen72076, Germany
- Cluster of Excellence EXC 2124 "Controlling Microbes to Fight Infections", University of Tübingen, Tübingen 72076, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen 72076 , Germany
| | - Christoph Slavetinsky
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen72076, Germany
- Cluster of Excellence EXC 2124 "Controlling Microbes to Fight Infections", University of Tübingen, Tübingen 72076, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen 72076 , Germany
- Pediatric Surgery and Urology, University Children's Hospital Tübingen, Tübingen 72076, Germany
| | - Lisa Gritsch
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen72076, Germany
- Cluster of Excellence EXC 2124 "Controlling Microbes to Fight Infections", University of Tübingen, Tübingen 72076, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen 72076 , Germany
| | - Rob van Dalen
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen72076, Germany
- Cluster of Excellence EXC 2124 "Controlling Microbes to Fight Infections", University of Tübingen, Tübingen 72076, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen 72076 , Germany
| | - Dorothee Kretschmer
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen72076, Germany
- Cluster of Excellence EXC 2124 "Controlling Microbes to Fight Infections", University of Tübingen, Tübingen 72076, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen 72076 , Germany
| | - Lisa Bleul
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen72076, Germany
- Cluster of Excellence EXC 2124 "Controlling Microbes to Fight Infections", University of Tübingen, Tübingen 72076, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen 72076 , Germany
| | - Christiane Wolz
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen72076, Germany
- Cluster of Excellence EXC 2124 "Controlling Microbes to Fight Infections", University of Tübingen, Tübingen 72076, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen 72076 , Germany
| | - Christopher Weidenmaier
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen72076, Germany
- Cluster of Excellence EXC 2124 "Controlling Microbes to Fight Infections", University of Tübingen, Tübingen 72076, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen 72076 , Germany
| | - Andreas Peschel
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen72076, Germany
- Cluster of Excellence EXC 2124 "Controlling Microbes to Fight Infections", University of Tübingen, Tübingen 72076, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen 72076 , Germany
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Prado Y, Pérez L, Eltit F, Echeverría C, Llancalahuen FM, Tapia P, González PA, Kalergis AM, Cabello-Verrugio C, Simon F. Procoagulant phenotype induced by oxidized high-density lipoprotein associates with acute kidney injury and death. Thromb Res 2023; 223:7-23. [PMID: 36689805 DOI: 10.1016/j.thromres.2023.01.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 01/12/2023] [Accepted: 01/16/2023] [Indexed: 01/21/2023]
Abstract
BACKGROUND Oxidative stress derived from severe systemic inflammation promotes conversion from high-density lipoprotein HDL to oxidized HDL (oxHDL), which interacts with vascular endothelial cells (ECs). OxHDL acquires procoagulant features playing a role in modulating coagulation, which has been linked with organ failure in ICU patients. However, whether oxHDL elicits a ECs-mediated procoagulant phenotype generating organ failure and death, and the underlying molecular mechanism is not known. Therefore, we studied whether oxHDL-treated rats and high-oxHDL ICU patients exhibit a procoagulant phenotype and its association with kidney injury and mortality and the endothelial underlying molecular mechanism. METHODS Human ECs, oxHDL-treated rats and ICU patients were subjected to several cellular and molecular studies, coagulation analyses, kidney injury assessment and mortality determination. RESULTS OxHDL-treated ECs showed a procoagulant protein expression reprograming characterized by increased E-/P-selectin and vWF mRNA expression through specific signaling pathways. OxHDL-treated rats exhibited a procoagulant phenotype and modified E-/P-selectin, vWF, TF and t-PA mRNA expression correlating with plasma TF, t-PA and D-dimer. Also, showed increased death events and the relative risk of death, and increased creatinine, urea, BUN/creatinine ratio, KIM-1, NGAL, β2M, and decreased eGFR, all concordant with kidney injury, correlated with plasma TF, t-PA and D-dimer. ICU patients showed correlation between plasma oxHDL and increased creatinine, cystatin, BUN, BUN/creatinine ratio, KIM-1, NGAL, β2M, and decreased GFR. Notably, ICU high-oxHDL patients showed decreased survival. Interestingly, altered coagulation factors TF, t-PA and D-dimer correlated with both increased oxHDL levels and kidney injury markers, indicating a connection between these factors. CONCLUSION Increased circulating oxHDL generates an endothelial-dependent procoagulant phenotype that associates with acute kidney injury and increased risk of death.
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Affiliation(s)
- Yolanda Prado
- Laboratory of Integrative Physiopathology, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile; Millennium Institute on Immunology and Immunotherapy, Santiago, Chile
| | - Lorena Pérez
- Laboratory of Integrative Physiopathology, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile
| | - Felipe Eltit
- Department of Materials Engineering, University of British Columbia, Vancouver, Canada; School of Biomedical Engineering, University of British Columbia, Vancouver, Canada; Centre for Hip Health and Mobility, Vancouver, BC, Canada
| | | | - Felipe M Llancalahuen
- Laboratory of Integrative Physiopathology, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile; Millennium Institute on Immunology and Immunotherapy, Santiago, Chile
| | - Pablo Tapia
- Unidad de Paciente Crítico Adulto, Hospital Clínico La Florida, La Florida, Santiago, Chile
| | - Pablo A González
- Millennium Institute on Immunology and Immunotherapy, Santiago, Chile; Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alexis M Kalergis
- Millennium Institute on Immunology and Immunotherapy, Santiago, Chile; Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile; Departamento de Endocrinología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Claudio Cabello-Verrugio
- Millennium Institute on Immunology and Immunotherapy, Santiago, Chile; Laboratory of Muscle Pathology, Fragility and Aging, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile; Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Universidad de Santiago de Chile, Santiago, Chile.
| | - Felipe Simon
- Laboratory of Integrative Physiopathology, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile; Millennium Institute on Immunology and Immunotherapy, Santiago, Chile; Millennium Nucleus of Ion Channel-Associated Diseases, Santiago, Chile.
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5
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Rojas M, Prado Y, Tapia P, Carreño LJ, Cabello-Verrugio C, Simon F. Oxidized High-Density Lipoprotein Induces Endothelial Fibrosis Promoting Hyperpermeability, Hypotension, and Increased Mortality. Antioxidants (Basel) 2022; 11:2469. [PMID: 36552677 PMCID: PMC9774523 DOI: 10.3390/antiox11122469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 12/09/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
During systemic inflammation, reactive oxygen species (ROS) are generated in the bloodstream, producing large amounts of oxidized HDL (oxHDL). OxHDL loses the vascular protective features of native HDL, acquiring detrimental actions. Systemic inflammation promotes endothelial fibrosis, characterized by adhesion protein downregulation and fibrotic-specific gene upregulation, disrupting endothelial monolayer integrity. Severe systemic inflammatory conditions, as found in critically ill patients in the intensive care unit (ICU), exhibit endothelial hyperpermeability, hypotension, and organ hypoperfusion, promoting organ dysfunction and increased mortality. Because endothelial fibrosis disturbs the endothelium, it is proposed that it is the cellular and molecular origin of endothelial hyperpermeability and the subsequent deleterious consequences. However, whether oxHDL is involved in this process is unknown. The aim of this study was to investigate the fibrotic effect of oxHDL on the endothelium, to elucidate the underlying molecular and cellular mechanism, and to determine its effects on vascular permeability, blood pressure, and mortality. The results showed that oxHDL induces endothelial fibrosis through the LOX-1/NOX-2/ROS/NF-κB pathway, TGF-β secretion, and ALK-5/Smad activation. OxHDL-treated rats showed endothelial hyperpermeability, hypotension, and an enhanced risk of death and mortality, which was prevented using an ALK-5 inhibitor and antioxidant diet consumption. Additionally, the ICU patients showed fibrotic endothelial cells, and the resuscitation fluid volume administered correlated with the plasma oxHDL levels associated with an elevated risk of death and mortality. We conclude that oxHDL generates endothelial fibrosis, impacting blood pressure regulation and survival.
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Affiliation(s)
- Macarena Rojas
- Laboratory of Integrative Physiopathology, Faculty of Life Science, Universidad Andres Bello, Santiago 8370186, Chile
| | - Yolanda Prado
- Laboratory of Integrative Physiopathology, Faculty of Life Science, Universidad Andres Bello, Santiago 8370186, Chile
- Millennium Institute on Immunology and Immunotherapy, Santiago 8331150, Chile
| | - Pablo Tapia
- Unidad de Paciente Crítico Adulto, Hospital Clínico La Florida, La Florida, Santiago 8242238, Chile
| | - Leandro J. Carreño
- Millennium Institute on Immunology and Immunotherapy, Santiago 8331150, Chile
- Programa de Inmunología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile
| | - Claudio Cabello-Verrugio
- Millennium Institute on Immunology and Immunotherapy, Santiago 8331150, Chile
- Laboratory of Muscle Pathology, Fragility and Aging, Faculty of Life Science, Universidad Andres Bello, Santiago 8370186, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Universidad de Santiago de Chile, Santiago 9170020, Chile
| | - Felipe Simon
- Laboratory of Integrative Physiopathology, Faculty of Life Science, Universidad Andres Bello, Santiago 8370186, Chile
- Millennium Institute on Immunology and Immunotherapy, Santiago 8331150, Chile
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Santiago 8380453, Chile
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Upregulated LOX-1 Receptor: Key Player of the Pathogenesis of Atherosclerosis. Curr Atheroscler Rep 2019; 21:38. [DOI: 10.1007/s11883-019-0801-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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7
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OxHDL controls LOX-1 expression and plasma membrane localization through a mechanism dependent on NOX/ROS/NF-κB pathway on endothelial cells. J Transl Med 2019; 99:421-437. [PMID: 30664710 DOI: 10.1038/s41374-018-0151-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 10/17/2018] [Accepted: 10/19/2018] [Indexed: 12/20/2022] Open
Abstract
Systemic inflammatory diseases enhance circulating oxidative stress levels, which results in the oxidation of circulating high-density lipoprotein (oxHDL). Endothelial cell function can be negatively impacted by oxHDL, but the underlying mechanisms for this remain unclear. Some reports indicate that the lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is also a receptor for oxHDL. However, it is unknown if oxHDL induces increased LOX-1 expression at the plasma membrane, as an event that supports endothelial dysfunction. Therefore, the aims of this study were to determine if oxHDL induces plasma-membrane level changes in LOX-1 and, if so, to describe the underlying mechanisms in endothelial cells. Our results demonstrate that the incubation of arterial or vein endothelial cells with oxHDL (and not HDL) induces the increase of LOX-1 expression at the plasma membrane; effect prevented by LOX-1 inhibition. Importantly, same results were observed in endothelial cells from oxHDL-treated rats. Furthermore, the observed oxHDL-induced LOX-1 expression is abolished by the down-regulation of NOX-2 expression with siRNA (and no others NOX isoforms), by the pharmacological inhibition of NAD(P)H oxidase (with DPI or apocynin) or by the inhibition of NF-κB transcription factor. Coherently, LOX-1 expression is augmented by the incubation of endothelial cells with H2O2 or GSSG even in absence of oxHDL, indicating that the NOX-2/ROS/ NF-κB axis is involved. Interestingly, oxHDL incubation also increases TNF-α expression, cytokine that induces LOX-1 expression. Thus, our results suggest a positive feedback mechanism for LOX-1 receptor during inflammatory condition where an oxidative burst will generate oxHDL from native HDL, activating LOX-1 receptor which in turn will increase the expression of NOX-2, TNF-α and LOX-1 receptor at the plasma membrane. In conclusion, oxHDL-induced translocation of LOX-1 to the plasma membrane could constitute an induction mechanism of endothelial dysfunction in systemic inflammatory diseases.
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Tian K, Ogura S, Little PJ, Xu SW, Sawamura T. Targeting LOX-1 in atherosclerosis and vasculopathy: current knowledge and future perspectives. Ann N Y Acad Sci 2018; 1443:34-53. [PMID: 30381837 DOI: 10.1111/nyas.13984] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 09/12/2018] [Accepted: 09/24/2018] [Indexed: 12/11/2022]
Abstract
LOX-1 (lectin-like oxidized low-density lipoprotein receptor-1; also known as OLR1) is the dominant receptor that recognizes and internalizes oxidized low-density lipoproteins (ox-LDLs) in endothelial cells. Several genetic variants of LOX-1 are associated with the risk and severity of coronary artery disease. The LOX-1-ox-LDL interaction induces endothelial dysfunction, leukocyte adhesion, macrophage-derived foam cell formation, smooth muscle cell proliferation and migration, and platelet activation. LOX-1 activation eventually leads to the rupture of atherosclerotic plaques and acute cardiovascular events. In addition, LOX-1 can be cleaved to generate soluble LOX-1 (sLOX-1), which is a useful diagnostic and prognostic marker for atherosclerosis-related diseases in human patients. Of therapeutic relevance, several natural products and clinically used drugs have emerged as LOX-1 inhibitors that have antiatherosclerotic actions. We hereby provide an updated overview of role of LOX-1 in atherosclerosis and associated vascular diseases, with an aim to highlighting the potential of LOX-1 as a novel theranostic tool for cardiovascular disease prevention and treatment.
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Affiliation(s)
- Kunming Tian
- Department of Preventive Medicine, School of Public Health, Zunyi Medical University, Zunyi, Guizhou, China
| | - Sayoko Ogura
- Division of Laboratory Medicine, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo, Japan
| | - Peter J Little
- School of Pharmacy, The University of Queensland, Wooloongabba, Queensland, Australia.,Department of Pharmacy, Xinhua College of Sun Yat-sen University, Guangzhou, China
| | - Suo-Wen Xu
- Aab Cardiovascular Research Institute, University of Rochester, Rochester, New York
| | - Tatsuya Sawamura
- Department of Physiology, School of Medicine, Shinshu University, Nagano, Japan.,Research Center for Next Generation Medicine, Shinshu University, Nagano, Japan
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Balzan S, Lubrano V. LOX-1 receptor: A potential link in atherosclerosis and cancer. Life Sci 2018; 198:79-86. [PMID: 29462603 DOI: 10.1016/j.lfs.2018.02.024] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 02/07/2018] [Accepted: 02/16/2018] [Indexed: 12/19/2022]
Abstract
Altered production of reactive oxygen species (ROS), causing lipid peroxidation and DNA damage, contributes to the progression of atherosclerosis and cancer. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is a lectin-like receptor for oxidized low-density lipoproteins (ox-LDL) primarily expressed in endothelial cells and vasculature-rich organs. LOX-1 receptors is a marker for atherosclerosis, and once activated by ox-LDL or other ligands, stimulates the expression of adhesion molecules, pro-inflammatory signaling pathways and proangiogenic proteins, including NF-kB and VEGF, in vascular endothelial cells and macrophages. Several different types of cancer reported LOX-1 gene upregulation, and numerous interplays exist concerning LOX-1 in atherosclerosis, metabolic diseases and cancer. One of them involves NF-kB, an oncogenic protein that regulates the transcription of several inflammatory genes response. In a model of cellular transformation, the MCF10A ER-Src, inhibition of LOX-1 gene reduces NF-kB activation and the inflammatory and hypoxia pathways, suggesting a mechanistic connection between cellular transformation and atherosclerosis. The remodeling proteins MMP-2 and MMP-9 have been found increased in angiogenesis in atherosclerotic plaque and also in human prostate cancer cells. In this review, we outlined the role of LOX-1 in atherogenesis and tumorigenesis as a potential link in these diseases, suggesting that LOX-1 inhibition could represent a promising strategy in the treatment of atherosclerosis and tumors.
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Affiliation(s)
- Silvana Balzan
- Institute of Clinical Physiology, CNR, Via Moruzzi 1, Pisa 56124, Italy.
| | - Valter Lubrano
- Fondazione CNR/Regione Toscana G. Monasterio, Via Moruzzi 1, Pisa 56124, Italy
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Hofmann A, Brunssen C, Morawietz H. Contribution of lectin-like oxidized low-density lipoprotein receptor-1 and LOX-1 modulating compounds to vascular diseases. Vascul Pharmacol 2017; 107:S1537-1891(17)30171-4. [PMID: 29056472 DOI: 10.1016/j.vph.2017.10.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 09/29/2017] [Accepted: 10/11/2017] [Indexed: 12/31/2022]
Abstract
The lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is the major receptor for binding and uptake of oxidized low-density lipoprotein (oxLDL) in endothelial cells. LOX-1 is also expressed in macrophages, smooth muscle cells and platelets. Following internalization of oxLDL, LOX-1 initiates a vicious cycle from activation of pro-inflammatory signaling pathways, thus promoting an increased reactive oxygen species formation and secretion of pro-inflammatory cytokines. LOX-1 plays a pivotal role in the development of endothelial dysfunction, foam cell and advanced lesions formation as well as in myocardial ischemia. Furthermore, it is known that LOX-1 plays a pivotal role in mitochondrial DNA damage, vascular cell apoptosis, and autophagy. A large number of studies provide evidence of a LOX-1's role in endothelial dysfunction, hypertension, diabetes, and obesity. In addition, novel insights into LOX-1 ligands and the activated signaling pathways have been gained. Recent studies have shown an interaction of LOX-1 with microRNA's, thus providing novel tools to regulate LOX-1 function. Because LOX-1 is increased in atherosclerotic plaques and contributes to endothelial dysfunction, several compounds were tested in vivo and in vitro to modulate the LOX-1 expression in therapeutic approaches.
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Affiliation(s)
- Anja Hofmann
- Division of Vascular Endothelium and Microcirculation, Department of Medicine III, University Hospital and Medical Faculty Carl Gustav Carus Dresden, Technische Universität Dresden, Dresden, Germany
| | - Coy Brunssen
- Division of Vascular Endothelium and Microcirculation, Department of Medicine III, University Hospital and Medical Faculty Carl Gustav Carus Dresden, Technische Universität Dresden, Dresden, Germany
| | - Henning Morawietz
- Division of Vascular Endothelium and Microcirculation, Department of Medicine III, University Hospital and Medical Faculty Carl Gustav Carus Dresden, Technische Universität Dresden, Dresden, Germany.
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Terminalia bellirica Extract Inhibits Low-Density Lipoprotein Oxidation and Macrophage Inflammatory Response in Vitro. Antioxidants (Basel) 2016; 5:antiox5020020. [PMID: 27314393 PMCID: PMC4931541 DOI: 10.3390/antiox5020020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 05/30/2016] [Accepted: 06/07/2016] [Indexed: 12/18/2022] Open
Abstract
The deciduous tree Terminalia bellirica found in Southeast Asia is extensively used in traditional Indian Ayurvedic medicine for the treatment of hypertension, rheumatism, and diabetes. The anti-atherogenic effect of Terminalia bellirica fruit has not been fully elucidated. Here, we investigated the effect of Terminalia bellirica extract (TBE) on low-density lipoprotein (LDL) oxidation and inflammation in macrophages. TBE showed 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (EC50: 7.2 ± 1.2 μg/mL) and 15-lipoxygenase inhibitory activity. TBE also significantly inhibited free radical-induced LDL oxidation compared to the solvent control in vitro. In THP-1 macrophages, TBE treatment resulted in significant decreases of the mRNA expression of tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), and lectin-like oxidized LDL receptor-1 (LOX-1). TBE also reduced matrix metalloproteinase (MMP)-9 secretion and intracellular reactive oxygen species (ROS) production in THP-1 macrophages. These results show that TBE has the inhibitory effects on LDL oxidation and macrophage inflammatory response in vitro, suggesting that its in vivo use might inhibit atherosclerosis plaque progression.
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Ivanov I, Kuhn H, Heydeck D. Structural and functional biology of arachidonic acid 15-lipoxygenase-1 (ALOX15). Gene 2015; 573:1-32. [PMID: 26216303 PMCID: PMC6728142 DOI: 10.1016/j.gene.2015.07.073] [Citation(s) in RCA: 153] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 06/26/2015] [Accepted: 07/21/2015] [Indexed: 12/14/2022]
Abstract
Lipoxygenases (LOX) form a family of lipid peroxidizing enzymes, which have been implicated in a number of physiological processes and in the pathogenesis of inflammatory, hyperproliferative and neurodegenerative diseases. They occur in two of the three domains of terrestrial life (bacteria, eucarya) and the human genome involves six functional LOX genes, which encode for six different LOX isoforms. One of these isoforms is ALOX15, which has first been described in rabbits in 1974 as enzyme capable of oxidizing membrane phospholipids during the maturational breakdown of mitochondria in immature red blood cells. During the following decades ALOX15 has extensively been characterized and its biological functions have been studied in a number of cellular in vitro systems as well as in various whole animal disease models. This review is aimed at summarizing the current knowledge on the protein-chemical, molecular biological and enzymatic properties of ALOX15 in various species (human, mouse, rabbit, rat) as well as its implication in cellular physiology and in the pathogenesis of various diseases.
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Affiliation(s)
- Igor Ivanov
- Institute of Biochemistry, Charité - University Medicine Berlin, Charitéplatz 1, CCO-Building, Virchowweg 6, D-10117 Berlin, Germany
| | - Hartmut Kuhn
- Institute of Biochemistry, Charité - University Medicine Berlin, Charitéplatz 1, CCO-Building, Virchowweg 6, D-10117 Berlin, Germany.
| | - Dagmar Heydeck
- Institute of Biochemistry, Charité - University Medicine Berlin, Charitéplatz 1, CCO-Building, Virchowweg 6, D-10117 Berlin, Germany
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Ding Z, Liu S, Wang X, Deng X, Fan Y, Shahanawaz J, Shmookler Reis RJ, Varughese KI, Sawamura T, Mehta JL. Cross-talk between LOX-1 and PCSK9 in vascular tissues. Cardiovasc Res 2015; 107:556-67. [PMID: 26092101 DOI: 10.1093/cvr/cvv178] [Citation(s) in RCA: 177] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 06/11/2015] [Indexed: 12/15/2022] Open
Abstract
AIMS Lectin-like ox-LDL receptor-1 (LOX-1) plays an important role in inflammatory diseases, such as atherosclerosis. Proprotein convertase subtilisin/kexin type 9 (PCSK9) modulates LDL receptor degradation and influences serum LDL levels. The present study was designed to investigate the possible interaction between PCSK9 and LOX-1. METHODS AND RESULTS In the first set of experiments, human vascular endothelial cells and smooth muscle cells were studied at baseline and after lipopolysaccharide (LPS) treatment (to create an inflammatory state). Both PCSK9 and LOX-1 were strongly induced by LPS treatment. To define the role of PCSK9 in LOX-1 expression, cells were transfected with siRNA against PCSK9, which resulted in reduced LOX-1 expression and function. On the other hand, cells exposed to recombinant hPCSK9 revealed enhanced LOX-1 expression (P < 0.05). To determine whether LOX-1 also regulates PCSK9, cultured cells in which LOX-1 was knocked down by siRNA expressed less PCSK9, whereas those transfected with hLOX-1 cDNA showed increased PCSK9 expression. The second set of experiments was carried out in wild-type (WT) and gene knockout (KO; LOX-1 and PCSK9) mice; LOX-1 KO mice showed much less PCSK9 (P < 0.05 vs. WT mice). PCSK9-KO mice showed much less LOX-1 (P < 0.05 vs. WT mice). Furthermore, we observed that mitochondrial reactive oxygen species (mtROS) plays an initiating role in the LOX-1/PCSK9 interaction, since mtROS induction enhanced and its inhibition reduced the expression of both PCSK9 and LOX-1. We also found that both LOX-1 and PCSK9 regulate adhesion molecules vascular cell adhesion molecule-1 expression. Finally, oxidized low-density lipoprotein and tumour necrosis factor-α, pro-inflammatory stimuli besides LPS, regulated PCSK9 expression that is mediated by the NF-κB signalling pathway. CONCLUSIONS These observations suggest that LOX-1 and PCSK9 positively influence each other's expression, especially during an inflammatory reaction. mtROS appear to be important initiators of PCSK9/LOX-1 expression.
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Affiliation(s)
- Zufeng Ding
- Central Arkansas Veterans Healthcare System and the University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
| | - Shijie Liu
- Central Arkansas Veterans Healthcare System and the University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
| | - Xianwei Wang
- Central Arkansas Veterans Healthcare System and the University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Xiaoyan Deng
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
| | - Yubo Fan
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
| | - Jiwani Shahanawaz
- Central Arkansas Veterans Healthcare System and the University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Robert J Shmookler Reis
- Central Arkansas Veterans Healthcare System and the University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Kattayi I Varughese
- Central Arkansas Veterans Healthcare System and the University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Tatsuya Sawamura
- Department of Physiology, Shinshu University School of Medicine, 3-1-1, Asahi, Matsumoto 390-8621, Japan
| | - Jawahar L Mehta
- Central Arkansas Veterans Healthcare System and the University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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High-Density Lipoprotein Prevents Endoplasmic Reticulum Stress-Induced Downregulation of Liver LOX-1 Expression. PLoS One 2015; 10:e0124285. [PMID: 25923692 PMCID: PMC4414515 DOI: 10.1371/journal.pone.0124285] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 03/12/2015] [Indexed: 01/08/2023] Open
Abstract
Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is a specific cell-surface receptor for oxidized-low-density lipoprotein (ox-LDL). The impact of high-density lipoprotein (HDL) on endoplasmic reticulum (ER) stress-mediated alteration of the LOX-1 level in hepatocytes remains unclear. We aimed to investigate the impact on LOX-1 expression by tunicamycin (TM)-induced ER stress and to determine the effect of HDL on TM-affected LOX-1 expression in hepatic L02 cells. Overexpression or silencing of related cellular genes was conducted in TM-treated cells. mRNA expression was evaluated using real-time polymerase chain reaction (PCR). Protein expression was analyzed by western blot and immunocytochemistry. Lipid uptake was examined by DiI-ox-LDL, followed by flow cytometric analysis. The results showed that TM induced the upregulation of ER chaperone GRP78, downregulation of LOX-1 expression, and lipid uptake. Knock down of IRE1 or XBP-1 effectively restored LOX-1 expression and improved lipid uptake in TM-treated cells. HDL treatment prevented the negative impact on LOX-1 expression and lipid uptake induced by TM. Additionally, 1–10 μg/mL HDL significantly reduced the GRP78, IRE1, and XBP-1 expression levels in TM-treated cells. Our findings reveal that HDL could prevent the TM-induced reduction of LOX-1 expression via inhibiting the IRE1/XBP-1 pathway, suggesting a new mechanism for beneficial roles of HDL in improving lipid metabolism.
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Valente AJ, Irimpen AM, Siebenlist U, Chandrasekar B. OxLDL induces endothelial dysfunction and death via TRAF3IP2: inhibition by HDL3 and AMPK activators. Free Radic Biol Med 2014; 70:117-28. [PMID: 24561578 PMCID: PMC4006317 DOI: 10.1016/j.freeradbiomed.2014.02.014] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 02/06/2014] [Accepted: 02/13/2014] [Indexed: 02/02/2023]
Abstract
Oxidized low-density lipoprotein (oxLDL) induces endothelial cell death through the activation of NF-κB and AP-1 pathways. TRAF3IP2 is a redox-sensitive cytoplasmic adapter protein and an upstream regulator of IKK/NF-κB and JNK/AP-1. Here we show that oxLDL-induced death in human primary coronary artery endothelial cells (ECs) was markedly attenuated by the knockdown of TRAF3IP2 or the lectin-like oxLDL receptor 1 (LOX-1). Further, oxLDL induced Nox2/superoxide-dependent TRAF3IP2 expression, IKK/p65 and JNK/c-Jun activation, and LOX-1 upregulation, suggesting a reinforcing mechanism. Similarly, the lysolipids present in oxLDL (16:0-LPC and 18:0-LPC) and minimally modified LDL also upregulated TRAF3IP2 expression. Notably, whereas native HDL3 reversed oxLDL-induced TRAF3IP2 expression and cell death, 15-lipoxygenase-modified HDL3 potentiated its proapoptotic effects. The activators of the AMPK/Akt pathway, adiponectin, AICAR, and metformin, attenuated superoxide generation, TRAF3IP2 expression, and oxLDL/TRAF3IP2-mediated EC death. Further, both HDL3 and adiponectin reversed oxLDL/TRAF3IP2-dependent monocyte adhesion to endothelial cells in vitro. Importantly, TRAF3IP2 gene deletion and the AMPK activators reversed oxLDL-induced impaired vasorelaxation ex vivo. These results indicate that oxLDL-induced endothelial cell death and dysfunction are mediated via TRAF3IP2 and that native HDL3 and the AMPK activators inhibit this response. Targeting TRAF3IP2 could potentially inhibit progression of atherosclerotic vascular diseases.
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Affiliation(s)
- Anthony J Valente
- Medicine, University of Texas Health Science Center and South Texas Veterans Health Care System, San Antonio, TX 78229, USA
| | - Anand M Irimpen
- Research Service, Southeast Louisiana Veterans Health Care System, New Orleans, LA 70161, USA; Heart and Vascular Institute, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Ulrich Siebenlist
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Bysani Chandrasekar
- Research Service, Southeast Louisiana Veterans Health Care System, New Orleans, LA 70161, USA; Heart and Vascular Institute, Tulane University School of Medicine, New Orleans, LA 70112, USA.
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Cutuli L, Pirillo A, Uboldi P, Kuehn H, Catapano AL. 15-lipoxygenase-mediated modification of HDL3 impairs eNOS activation in human endothelial cells. Lipids 2014; 49:317-26. [PMID: 24570151 DOI: 10.1007/s11745-014-3888-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 02/12/2014] [Indexed: 01/08/2023]
Abstract
Caveolae are cholesterol and glycosphingolipids-enriched microdomains of plasma membranes. Caveolin-1 represents the major structural protein of caveolae, that also contain receptors and molecules involved in signal transduction pathways. Caveolae are particularly abundant in endothelial cells, where they play important physiological and pathological roles in regulating endothelial cell functions. Several molecules with relevant functions in endothelial cells are localized in caveolae, including endothelial nitric oxide synthase (eNOS), which regulates the production of nitric oxide, and scavenger receptor class B type I (SR-BI), which plays a key role in the induction of eNOS activity mediated by high density lipoproteins (HDL). HDL have several atheroprotective functions, including a positive effect on endothelial cells, as it is a potent agonist of eNOS through the interaction with SR-BI. However, the oxidative modification of HDL may impair their protective role. In the present study we evaluated the effect of 15-lipoxygenase-mediated modification of HDL3 on the expression and/or activity of some proteins localized in endothelial caveolae and involved in the nitric oxide generation pathway. We found that after modification, HDL3 failed to activate eNOS and to induce NO production, due to both a reduced ability to interact with its own receptor SR-BI and to a reduced expression of SR-BI in cells exposed to modified HDL. These findings suggest that modification of HDL may reduce its endothelial-protective role also by interfering with vasodilatory function of HDL.
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Affiliation(s)
- Lucia Cutuli
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Milan, Italy
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HDL cholesterol in cardiovascular diseases: the good, the bad, and the ugly? Int J Cardiol 2013; 168:3157-9. [PMID: 23962777 DOI: 10.1016/j.ijcard.2013.07.210] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 07/20/2013] [Indexed: 12/19/2022]
Abstract
Atherosclerotic cardiovascular diseases are the leading cause of death in developed and developing countries. HDL-raising therapeutic modalities (such as cholesterol ester transferase protein (CETP) inhibitors) are being developed to combat these diseases. However, recent setback of two CETP inhibitors (Torcetrapib and Dalcetrapib) has highlighted the importance of measuring qualitative functionality of HDL particles, rather than focusing quantitatively on HDL cholesterol serum concentrations. It has been known that, HDL from patients with coronary artery disease (CAD) (i.e., HDL(CAD)) limits the anti-inflammatory and endothelial repair properties of normal HDL, due to the activation of lectin-like oxidized LDL receptor-1 (LOX-1), thereby causing failure in endothelial nitric oxide (NO) production. A more recent study (Immunity 2013; 38: 754-768) also demonstrates that HDL from patients with chronic kidney dysfunction (CKD) (i.e., HDL(CKD)), unlike its healthy counterpart (i.e., HDL(Healthy)), promotes superoxide production, reduces NO bioavailability and raises blood pressure via toll-like receptor-2 (TLR-2) activation. This study provides novel insights into understanding why HDL-raising agents failed to demonstrate beneficial effects on cardiovascular mortality in large clinical trials and why CKD accelerates the development of atherosclerosis in CAD patients. Further research is warranted to elucidate whether HDL(CKD) and HDL(CAD) participate in other cellular processes in atherosclerosis, such as foam cell formation, the proliferation and migration of smooth muscle cells, and most importantly, plaque destabilization.
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LOX-1, OxLDL, and atherosclerosis. Mediators Inflamm 2013; 2013:152786. [PMID: 23935243 PMCID: PMC3723318 DOI: 10.1155/2013/152786] [Citation(s) in RCA: 516] [Impact Index Per Article: 46.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 06/16/2013] [Indexed: 01/07/2023] Open
Abstract
Oxidized low-density lipoprotein (OxLDL) contributes to the atherosclerotic plaque formation and progression by several mechanisms, including the induction of endothelial cell activation and dysfunction, macrophage foam cell formation, and smooth muscle cell migration and proliferation. Vascular wall cells express on their surface several scavenger receptors that mediate the cellular effects of OxLDL. The lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is the main OxLDL receptor of endothelial cells, and it is expressed also in macrophages and smooth muscle cells. LOX-1 is almost undetectable under physiological conditions, but it is upregulated following the exposure to several proinflammatory and proatherogenic stimuli and can be detected in animal and human atherosclerotic lesions. The key contribution of LOX-1 to the atherogenic process has been confirmed in animal models; LOX-1 knockout mice exhibit reduced intima thickness and inflammation and increased expression of protective factors; on the contrary, LOX-1 overexpressing mice present an accelerated atherosclerotic lesion formation which is associated with increased inflammation. In humans, LOX-1 gene polymorphisms were associated with increased susceptibility to myocardial infarction. Inhibition of the LOX-1 receptor with chemicals or antisense nucleotides is currently being investigated and represents an emerging approach for controlling OxLDL-LOX-1 mediated proatherogenic effects.
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Pirillo A, Norata GD, Catapano AL. High-density lipoprotein subfractions--what the clinicians need to know. Cardiology 2013; 124:116-25. [PMID: 23428644 DOI: 10.1159/000346463] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 12/06/2012] [Indexed: 11/19/2022]
Abstract
Although the inverse relationship between plasma levels of high-density lipoprotein (HDL) and cardiovascular disease has been largely demonstrated, many observations have suggested that the assessment of HDL functionality might be more informative than a simple measurement of HDL-cholesterol plasma levels. HDLs are a class of structurally and functionally heterogeneous particles; in atherosclerosis-related diseases, changes in HDL subfraction levels and functions are frequently observed. Circulating levels of large HDL particles are decreased in dyslipidaemic conditions, while levels of small dense HDL particles are increased in patients with coronary heart disease. Furthermore, specific genetic defects in proteins involved in HDL metabolism significantly impact the distribution of HDL subpopulations. Finally, many drugs used for dyslipidaemia induce changes in HDL subfractions strictly related to cardiovascular disease. Although several methods exist to evaluate HDL subclass levels, most of them are not easily applicable in clinical practice, due to the costs and high variability. However, the possibility to measure the levels of specific HDL subfractions in patients with atherosclerosis-related diseases might help to better define their cardiovascular risk.
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Affiliation(s)
- Angela Pirillo
- Center for the Study of Atherosclerosis, Bassini Hospital, Cinisello Balsamo, Milan, Italy
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