1
|
Chambers KL, Myerscough MR, Watson MG, Byrne HM. Blood Lipoproteins Shape the Phenotype and Lipid Content of Early Atherosclerotic Lesion Macrophages: A Dual-Structured Mathematical Model. Bull Math Biol 2024; 86:112. [PMID: 39093509 PMCID: PMC11297092 DOI: 10.1007/s11538-024-01342-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Accepted: 07/16/2024] [Indexed: 08/04/2024]
Abstract
Macrophages in atherosclerotic lesions exhibit a spectrum of behaviours or phenotypes. The phenotypic distribution of monocyte-derived macrophages (MDMs), its correlation with MDM lipid content, and relation to blood lipoprotein densities are not well understood. Of particular interest is the balance between low density lipoproteins (LDL) and high density lipoproteins (HDL), which carry bad and good cholesterol respectively. To address these issues, we have developed a mathematical model for early atherosclerosis in which the MDM population is structured by phenotype and lipid content. The model admits a simpler, closed subsystem whose analysis shows how lesion composition becomes more pathological as the blood density of LDL increases relative to the HDL capacity. We use asymptotic analysis to derive a power-law relationship between MDM phenotype and lipid content at steady-state. This relationship enables us to understand why, for example, lipid-laden MDMs have a more inflammatory phenotype than lipid-poor MDMs when blood LDL lipid density greatly exceeds HDL capacity. We show further that the MDM phenotype distribution always attains a local maximum, while the lipid content distribution may be unimodal, adopt a quasi-uniform profile or decrease monotonically. Pathological lesions exhibit a local maximum in both the phenotype and lipid content MDM distributions, with the maximum at an inflammatory phenotype and near the lipid content capacity respectively. These results illustrate how macrophage heterogeneity arises in early atherosclerosis and provide a framework for future model validation through comparison with single-cell RNA sequencing data.
Collapse
Affiliation(s)
- Keith L Chambers
- Wolfson Centre for Mathematical Biology, Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford, Oxfordshire, OX2 6GG, UK.
| | - Mary R Myerscough
- School of Mathematics and Statistics, University of Sydney, Carslaw Building, Eastern Avenue, Camperdown, Sydney, NSW, 2006, Australia
| | - Michael G Watson
- School of Mathematics and Statistics, University of New South Wales, Anita B. Lawrence Centre, University Mall, UNSW, Kensington, Sydney, NSW, 2052, Australia
| | - Helen M Byrne
- Wolfson Centre for Mathematical Biology, Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford, Oxfordshire, OX2 6GG, UK
- Ludwig Institute for Cancer Research, University of Oxford, Old Road Campus Research Build, Roosevelt Dr, Headington, Oxford, Oxfordshire, OX3 7DQ, UK
| |
Collapse
|
2
|
Geh EN, Swertfeger DK, Sexmith H, Heink A, Tarapore P, Melchior JT, Davidson WS, Shah AS. A novel assay to measure low-density lipoproteins binding to proteoglycans. PLoS One 2024; 19:e0291632. [PMID: 38295021 PMCID: PMC10830033 DOI: 10.1371/journal.pone.0291632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 09/04/2023] [Indexed: 02/02/2024] Open
Abstract
BACKGROUND The binding of low-density lipoprotein (LDL) to proteoglycans (PGs) in the extracellular matrix (ECM) of the arterial intima is a key initial step in the development of atherosclerosis. Although many techniques have been developed to assess this binding, most of the methods are labor-intensive and technically challenging to standardize across research laboratories. Thus, sensitive, and reproducible assay to detect LDL binding to PGs is needed to screen clinical populations for atherosclerosis risk. OBJECTIVES The aim of this study was to develop a quantitative, and reproducible assay to evaluate the affinity of LDL towards PGs and to replicate previously published results on LDL-PG binding. METHODS Immunofluorescence microscopy was performed to visualize the binding of LDL to PGs using mouse vascular smooth muscle (MOVAS) cells. An in-cell ELISA (ICE) was also developed and optimized to quantitatively measure LDL-PG binding using fixed MOVAS cells cultured in a 96-well format. RESULTS We used the ICE assay to show that, despite equal APOB concentrations, LDL isolated from adults with cardiovascular disease bound to PG to a greater extent than LDL isolated from adults without cardiovascular disease (p<0.05). CONCLUSION We have developed an LDL-PG binding assay that is capable of detecting differences in PG binding affinities despite equal APOB concentrations. Future work will focus on candidate apolipoproteins that enhance or diminish this interaction.
Collapse
Affiliation(s)
- Esmond N. Geh
- Division of Endocrinology, Cincinnati Children’s Hospital Medical Center & the Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Debi K. Swertfeger
- Division of Endocrinology, Cincinnati Children’s Hospital Medical Center & the Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Hannah Sexmith
- Division of Endocrinology, Cincinnati Children’s Hospital Medical Center & the Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Anna Heink
- Division of Endocrinology, Cincinnati Children’s Hospital Medical Center & the Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Pheruza Tarapore
- Center for Lipid and Arteriosclerosis Science, Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - John T. Melchior
- Center for Lipid and Arteriosclerosis Science, Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio, United States of America
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, United States of America
- Department of Neurology, Oregon Health and Science University, Portland, Oregon, United States of America
| | - W. Sean Davidson
- Center for Lipid and Arteriosclerosis Science, Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Amy Sanghavi Shah
- Division of Endocrinology, Cincinnati Children’s Hospital Medical Center & the Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| |
Collapse
|
3
|
Benitez S, Puig N, Rives J, Solé A, Sánchez-Quesada JL. Can Electronegative LDL Act as a Multienzymatic Complex? Int J Mol Sci 2023; 24:ijms24087074. [PMID: 37108253 PMCID: PMC10138509 DOI: 10.3390/ijms24087074] [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: 03/15/2023] [Revised: 04/06/2023] [Accepted: 04/10/2023] [Indexed: 04/29/2023] Open
Abstract
Electronegative LDL (LDL(-)) is a minor form of LDL present in blood for which proportions are increased in pathologies with increased cardiovascular risk. In vitro studies have shown that LDL(-) presents pro-atherogenic properties, including a high susceptibility to aggregation, the ability to induce inflammation and apoptosis, and increased binding to arterial proteoglycans; however, it also shows some anti-atherogenic properties, which suggest a role in controlling the atherosclerotic process. One of the distinctive features of LDL(-) is that it has enzymatic activities with the ability to degrade different lipids. For example, LDL(-) transports platelet-activating factor acetylhydrolase (PAF-AH), which degrades oxidized phospholipids. In addition, two other enzymatic activities are exhibited by LDL(-). The first is type C phospholipase activity, which degrades both lysophosphatidylcholine (LysoPLC-like activity) and sphingomyelin (SMase-like activity). The second is ceramidase activity (CDase-like). Based on the complementarity of the products and substrates of these different activities, this review speculates on the possibility that LDL(-) may act as a sort of multienzymatic complex in which these enzymatic activities exert a concerted action. We hypothesize that LysoPLC/SMase and CDase activities could be generated by conformational changes in apoB-100 and that both activities occur in proximity to PAF-AH, making it feasible to discern a coordinated action among them.
Collapse
Affiliation(s)
- Sonia Benitez
- Cardiovascular Biochemistry Group, Research Institute of the Hospital de la Santa Creu i Sant Pau (IIB Sant Pau), 08041 Barcelona, Spain
- CIBER of Diabetes and Related Metabolic Diseases (CIBERDEM), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Núria Puig
- Cardiovascular Biochemistry Group, Research Institute of the Hospital de la Santa Creu i Sant Pau (IIB Sant Pau), 08041 Barcelona, Spain
- Biochemistry and Molecular Biology Department, Universitat Autònoma de Barcelona, 08193 Cerdanyola, Spain
| | - José Rives
- Cardiovascular Biochemistry Group, Research Institute of the Hospital de la Santa Creu i Sant Pau (IIB Sant Pau), 08041 Barcelona, Spain
- Biochemistry and Molecular Biology Department, Universitat Autònoma de Barcelona, 08193 Cerdanyola, Spain
| | - Arnau Solé
- Cardiovascular Biochemistry Group, Research Institute of the Hospital de la Santa Creu i Sant Pau (IIB Sant Pau), 08041 Barcelona, Spain
- Biochemistry and Molecular Biology Department, Universitat Autònoma de Barcelona, 08193 Cerdanyola, Spain
| | - José Luis Sánchez-Quesada
- Cardiovascular Biochemistry Group, Research Institute of the Hospital de la Santa Creu i Sant Pau (IIB Sant Pau), 08041 Barcelona, Spain
- CIBER of Diabetes and Related Metabolic Diseases (CIBERDEM), Instituto de Salud Carlos III, 28029 Madrid, Spain
| |
Collapse
|
4
|
Electronegative LDL Is Associated with Plaque Vulnerability in Patients with Ischemic Stroke and Carotid Atherosclerosis. Antioxidants (Basel) 2023; 12:antiox12020438. [PMID: 36829998 PMCID: PMC9952764 DOI: 10.3390/antiox12020438] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/06/2023] [Accepted: 02/08/2023] [Indexed: 02/12/2023] Open
Abstract
Owing to the high risk of recurrence, identifying indicators of carotid plaque vulnerability in atherothrombotic ischemic stroke is essential. In this study, we aimed to identify modified LDLs and antioxidant enzymes associated with plaque vulnerability in plasma from patients with a recent ischemic stroke and carotid atherosclerosis. Patients underwent an ultrasound, a CT-angiography, and an 18F-FDG PET. A blood sample was obtained from patients (n = 64, 57.8% with stenosis ≥50%) and healthy controls (n = 24). Compared to the controls, patients showed lower levels of total cholesterol, LDL cholesterol, HDL cholesterol, apolipoprotein B (apoB), apoA-I, apoA-II, and apoE, and higher levels of apoJ. Patients showed lower platelet-activating factor acetylhydrolase (PAF-AH) and paraoxonase-1 (PON-1) enzymatic activities in HDL, and higher plasma levels of oxidized LDL (oxLDL) and electronegative LDL (LDL(-)). The only difference between patients with stenosis ≥50% and <50% was the proportion of LDL(-). In a multivariable logistic regression analysis, the levels of LDL(-), but not of oxLDL, were independently associated with the degree of carotid stenosis (OR: 5.40, CI: 1.15-25.44, p < 0.033), the presence of hypoechoic plaque (OR: 7.52, CI: 1.26-44.83, p < 0.027), and of diffuse neovessels (OR: 10.77, CI: 1.21-95.93, p < 0.033), indicating that an increased proportion of LDL(-) is associated with vulnerable atherosclerotic plaque.
Collapse
|
5
|
Nikiforov NG, Zlenko DV, Orekhova VA, Melnichenko AA, Orekhov AN. Local Accumulation of Lymphocytes in the Intima of Human Aorta Is Associated with Giant Multinucleated Endothelial Cells: Possible Explanation for Mosaicism of Atherosclerosis. Int J Mol Sci 2022; 23:ijms23031059. [PMID: 35162983 PMCID: PMC8835708 DOI: 10.3390/ijms23031059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/14/2022] [Accepted: 01/14/2022] [Indexed: 02/04/2023] Open
Abstract
Distribution of different types of atherosclerotic lesions in the arterial wall is not diffuse, but is characterized by mosaicism. The causes of such distribution remain to be established. At the early stages of atherogenesis, low-density lipoprotein (LDL) particles and immune cells penetrate into the intimal layer of the arterial wall through the endothelium. In adult humans, the luminal surface of the arterial wall is a heterogeneous monolayer of cells with varying morphology including typical endothelial cells (ECs) and multinucleated variant endothelial cells (MVECs). We hypothesized that distribution of MVECs in the endothelial monolayer can be related to the distribution pattern of early atherosclerotic lesions. We obtained en face preparations of intact adult (22–59 years old) aortic wall sections that allowed us to study the endothelial monolayer and the subendothelial layer. We compared the distribution of MVECs in the endothelial monolayer with the localization of early atherosclerotic lesions in the subendothelial layer, which were characterized by lipid accumulation and immune cell recruitment. In primary culture, MVECs demonstrated increased phagocytic activity compared to mononuclear ECs. Moreover, we have shown that unaffected aortic intima contained associates formed as a result of aggregation and/or fusion of LDL particles that are non-randomly distributed. This indicated that MVECs may be involved in the accumulation of LDL in the subendothelial layer through increased transcytosis. Interaction of LDL with subendothelial cells of human aorta in primary culture increased their adhesive properties toward circulating immune cells. Study of unaffected aortic intima revealed non-random distribution of leukocytes in the subendothelial layer and increased localization of CD45+ leukocytes in the subendothelial layer adjacent to MVECs. Together, our observations indicate that MVECs may be responsible for the distribution of atherosclerotic lesions in the arterial wall by participating in LDL internalization and immune cell recruitment.
Collapse
Affiliation(s)
- Nikita G. Nikiforov
- Laboratory of Medical Genetics, Institute of Experimental Cardiology, National Medical Research Center of Cardiology, 121552 Moscow, Russia;
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia
- Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, 125315 Moscow, Russia;
| | - Dmitry V. Zlenko
- N.N. Semenov Federal Research Center for Chemical Physics RAS, 119991 Moscow, Russia;
- Faculty of Biology, M.V. Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Varvara A. Orekhova
- Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, 125315 Moscow, Russia;
- Correspondence: (V.A.O.); (A.N.O.); Tel.: +7-9057506815 (A.N.O.)
| | - Alexandra A. Melnichenko
- Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, 125315 Moscow, Russia;
| | - Alexander N. Orekhov
- Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, 125315 Moscow, Russia;
- Laboratory of Infection Pathology and Molecular Microecology, Institute of Human Morphology, 117418 Moscow, Russia
- Correspondence: (V.A.O.); (A.N.O.); Tel.: +7-9057506815 (A.N.O.)
| |
Collapse
|
6
|
Steffen HLM, Anderson JLC, Poot ML, Lei Y, Connelly MA, Bakker SJL, Öörni K, Tietge UJF. Proteoglycan binding as proatherogenic function metric of apoB-containing lipoproteins and chronic kidney graft failure. J Lipid Res 2021; 62:100083. [PMID: 33939983 PMCID: PMC8173310 DOI: 10.1016/j.jlr.2021.100083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 04/14/2021] [Indexed: 12/31/2022] Open
Abstract
Lipoprotein-proteoglycan binding is an early key event in atherosclerotic lesion formation and thus conceivably could play a major role in vasculopathy-driven chronic graft failure and cardiovascular mortality in renal transplant recipients. The present study investigated whether lipoprotein-proteoglycan binding susceptibility (LPBS) of apoB-containing lipoproteins and levels of the classical atherosclerosis biomarker LDL-C were associated with cardiovascular mortality (n = 130) and graft failure (n = 73) in 589 renal transplant recipients who were followed up from at least 1 year after transplantation for 9.5 years. At baseline, LPBS was significantly higher in patients who subsequently developed graft failure than in those with a surviving graft (1.68 ± 0.93 vs. 1.46 ± 0.49 nmol/mmol, P = 0.001). Cox regression analysis showed an association between LPBS and chronic graft failure in an age- and sex-adjusted model (hazard ratio: 1.45; 95% CI, 1.14-1.85; P = 0.002), but no association was observed with cardiovascular mortality. LDL-C levels were not associated with graft failure or cardiovascular mortality. This study shows that measurement of cholesterol retention outperformed the traditionally used quantitative parameter of LDL-C levels in predicting graft failure, suggesting a higher relevance of proatherogenic function than the quantity of apoB-containing lipoproteins in chronic kidney graft failure.
Collapse
Affiliation(s)
- Hannah L M Steffen
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Josephine L C Anderson
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Margot L Poot
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Yu Lei
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Margery A Connelly
- Laboratory Corporation of America Holdings (LabCorp), Morrisville, NC, USA
| | - Stephan J L Bakker
- Department of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Katariina Öörni
- Atherosclerosis Research Laboratory, Wihuri Research Institute, Helsinki, Finland; Molecular and Integrative Bioscience Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Uwe J F Tietge
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden; Clinical Chemistry, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden.
| |
Collapse
|
7
|
Öörni K, Kovanen PT. Aggregation Susceptibility of Low-Density Lipoproteins-A Novel Modifiable Biomarker of Cardiovascular Risk. J Clin Med 2021; 10:1769. [PMID: 33921661 PMCID: PMC8074066 DOI: 10.3390/jcm10081769] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 03/31/2021] [Accepted: 04/13/2021] [Indexed: 01/07/2023] Open
Abstract
Circulating low-density lipoprotein (LDL) particles enter the arterial intima where they bind to the extracellular matrix and become modified by lipases, proteases, and oxidizing enzymes and agents. The modified LDL particles aggregate and fuse into larger matrix-bound lipid droplets and, upon generation of unesterified cholesterol, cholesterol crystals are also formed. Uptake of the aggregated/fused particles and cholesterol crystals by macrophages and smooth muscle cells induces their inflammatory activation and conversion into foam cells. In this review, we summarize the causes and consequences of LDL aggregation and describe the development and applications of an assay capable of determining the susceptibility of isolated LDL particles to aggregate when exposed to human recombinant sphingomyelinase enzyme ex vivo. Significant person-to-person differences in the aggregation susceptibility of LDL particles were observed, and such individual differences largely depended on particle lipid composition. The presence of aggregation-prone LDL in the circulation predicted future cardiovascular events in patients with atherosclerotic cardiovascular disease. We also discuss means capable of reducing LDL particles' aggregation susceptibility that could potentially inhibit LDL aggregation in the arterial wall. Whether reductions in LDL aggregation susceptibility are associated with attenuated atherogenesis and a reduced risk of atherosclerotic cardiovascular diseases remains to be studied.
Collapse
Affiliation(s)
- Katariina Öörni
- Wihuri Research Institute, 00290 Helsinki, Finland;
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, 00014 Helsinki, Finland
| | | |
Collapse
|
8
|
Jayaraman S, Chavez OR, Pérez A, Miñambres I, Sánchez-Quesada JL, Gursky O. Binding to heparin triggers deleterious structural and biochemical changes in human low-density lipoprotein, which are amplified in hyperglycemia. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158712. [PMID: 32289504 DOI: 10.1016/j.bbalip.2020.158712] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 03/31/2020] [Accepted: 04/08/2020] [Indexed: 12/15/2022]
Abstract
Low-density lipoprotein (LDL) binding to arterial proteoglycans initiates LDL retention and modification in the arterial wall, triggering atherosclerosis. The details of this binding, its effectors, and its ramifications are incompletely understood. We combined heparin affinity chromatography with biochemical, spectroscopic and electron microscopic techniques to show that brief binding to heparin initiates irreversible pro-atherogenic remodeling of human LDL. This involved decreased structural stability of LDL and increased susceptibility to hydrolysis, oxidation and fusion. Furthermore, phospholipid hydrolysis, mild oxidation and/or glycation of LDL in vitro increase the proteolytic susceptibility of apoB and its heparin binding affinity, perhaps by unmasking additional heparin-binding sites. For LDL from hyperglycemic type-2 diabetic patients, heparin binding was particularly destabilizing and caused apoB fragmentation and LDL fusion. However, for similar patients whose glycemic control was restored upon therapy, LDL-heparin binding affinity was rectified and LDL structural stability was partially restored. These results complement previous studies of LDL binding to arterial proteoglycans and suggest that such interactions may produce a particularly pro-atherogenic subclass of electronegative LDL. In summary, binding to heparin alters apoB conformation, perhaps by partially peeling it off the lipid, and triggers pro-atherogenic LDL modifications including hydrolysis, oxidation, and destabilization. Furthermore, phospholipid lipolysis, mild oxidation and glycation of LDL in vitro strengthen its binding to heparin, which helps explain stronger binding observed in hyperglycemic LDL. Combined effects of hyperglycemia and heparin binding are especially deleterious but are largely rectified upon diabetes therapy. These findings help establish a mechanistic link between diabetes and atherosclerosis.
Collapse
Affiliation(s)
- Shobini Jayaraman
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA 02118, USA.
| | - Olivia R Chavez
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA 02118, USA
| | - Antonio Pérez
- Endocrinology Department of the Hospital de la Santa Creu i Sant Pau, Barcelona, Spain; CIBER of Diabetes and Metabolic Diseases (CIBERDEM), Spain
| | - Inka Miñambres
- Endocrinology Department of the Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Jose Luis Sánchez-Quesada
- CIBER of Diabetes and Metabolic Diseases (CIBERDEM), Spain; Cardiovascular Biochemistry Group, Research Institute of the Hospital de Sant Pau, CIBERDEM, Barcelona, Spain
| | - Olga Gursky
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA 02118, USA; Amyloidosis Treatment and Research Center, Boston University School of Medicine, Boston MA, USA
| |
Collapse
|
9
|
Puig N, Montolio L, Camps-Renom P, Navarra L, Jiménez-Altayó F, Jiménez-Xarrié E, Sánchez-Quesada JL, Benitez S. Electronegative LDL Promotes Inflammation and Triglyceride Accumulation in Macrophages. Cells 2020; 9:cells9030583. [PMID: 32121518 PMCID: PMC7140452 DOI: 10.3390/cells9030583] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/26/2020] [Accepted: 02/26/2020] [Indexed: 12/22/2022] Open
Abstract
Electronegative low-density lipoprotein (LDL) (LDL(−)), a modified LDL that is present in blood and exerts atherogenic effects on endothelial cells and monocytes. This study aimed to determine the action of LDL(−) on monocytes differentiated into macrophages. LDL(−) and in vitro-modified LDLs (oxidized, aggregated, and acetylated) were added to macrophages derived from THP1 monocytes over-expressing CD14 (THP1-CD14). Then, cytokine release, cell differentiation, lipid accumulation, and gene expression were measured by ELISA, flow cytometry, thin-layer chromatography, and real-time PCR, respectively. LDL(−) induced more cytokine release in THP1-CD14 macrophages than other modified LDLs. LDL(−) also promoted morphological changes ascribed to differentiated macrophages. The addition of high-density lipoprotein (HDL) and anti-TLR4 counteracted these effects. LDL(−) was highly internalized by macrophages, and it was the major inductor of intracellular lipid accumulation in triglyceride-enriched lipid droplets. In contrast to inflammation, the addition of anti-TLR4 had no effect on lipid accumulation, thus suggesting an uptake pathway alternative to TLR4. In this regard, LDL(−) upregulated the expression of the scavenger receptors CD36 and LOX-1, as well as several genes involved in triglyceride (TG) accumulation. The importance and novelty of the current study is that LDL(−), a physiologically modified LDL, exerted atherogenic effects in macrophages by promoting differentiation, inflammation, and triglyceride-enriched lipid droplets formation in THP1-CD14 macrophages, probably through different receptors.
Collapse
Affiliation(s)
- Núria Puig
- Cardiovascular Biochemistry, Biomedical Research Institute Sant Pau (IIB-Sant Pau), 08041 Barcelona, Spain; (N.P.); (L.M.); (L.N.)
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Building M, Universitat Autònoma de Barcelona (UAB), 08193 Cerdanyola del Vallès, Barcelona, Spain
| | - Lara Montolio
- Cardiovascular Biochemistry, Biomedical Research Institute Sant Pau (IIB-Sant Pau), 08041 Barcelona, Spain; (N.P.); (L.M.); (L.N.)
| | - Pol Camps-Renom
- Stroke Unit, Department of Neurology, Hospital de la Santa Creu i Sant Pau, and IIB-Sant Pau, 08041 Barcelona, Spain;
| | - Laia Navarra
- Cardiovascular Biochemistry, Biomedical Research Institute Sant Pau (IIB-Sant Pau), 08041 Barcelona, Spain; (N.P.); (L.M.); (L.N.)
| | - Francesc Jiménez-Altayó
- Departament of Pharmacology. Neuroscience Institute. Faculty of Medicine, UAB, 08193 Cerdanyola del Vallès, Barcelona, Spain;
| | - Elena Jiménez-Xarrié
- Stroke Unit, Department of Neurology, Hospital de la Santa Creu i Sant Pau, and IIB-Sant Pau, 08041 Barcelona, Spain;
- Correspondence: (E.J.-X.); (J.L.S.-Q.); (S.B.); Tel.: +34-93-553-7595 (S.B.)
| | - Jose Luis Sánchez-Quesada
- Cardiovascular Biochemistry, Biomedical Research Institute Sant Pau (IIB-Sant Pau), 08041 Barcelona, Spain; (N.P.); (L.M.); (L.N.)
- CIBER of Diabetes and Metabolic Diseases (CIBERDEM), 28029 Madrid, Spain
- Correspondence: (E.J.-X.); (J.L.S.-Q.); (S.B.); Tel.: +34-93-553-7595 (S.B.)
| | - Sonia Benitez
- Cardiovascular Biochemistry, Biomedical Research Institute Sant Pau (IIB-Sant Pau), 08041 Barcelona, Spain; (N.P.); (L.M.); (L.N.)
- Correspondence: (E.J.-X.); (J.L.S.-Q.); (S.B.); Tel.: +34-93-553-7595 (S.B.)
| |
Collapse
|
10
|
Ahmed O, Littmann K, Gustafsson U, Pramfalk C, Öörni K, Larsson L, Minniti ME, Sahlin S, Camejo G, Parini P, Eriksson M. Ezetimibe in Combination With Simvastatin Reduces Remnant Cholesterol Without Affecting Biliary Lipid Concentrations in Gallstone Patients. J Am Heart Assoc 2019; 7:e009876. [PMID: 30561264 PMCID: PMC6405603 DOI: 10.1161/jaha.118.009876] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Background In randomized trials (SHARP [Study of Heart and Renal Protection], IMPROVE‐IT [Improved Reduction of Outcomes: Vytorin Efficacy International Trial]), combination of statin and ezetimibe resulted in additional reduction of cardiovascular events. The reduction was greater in patients with type 2 diabetes mellitus (T2DM), where elevated remnant cholesterol and high cardiovascular disease risk is characteristic. To evaluate possible causes behind these results, 40 patients eligible for cholecystectomy, randomized to simvastatin, ezetimibe, combined treatment (simvastatin+ezetimibe), or placebo treatment during 4 weeks before surgery, were studied. Methods and Results Fasting blood samples were taken before treatment start and at the end (just before surgery). Bile samples and liver biopsies were collected during surgery. Hepatic gene expression levels were assessed with qPCR. Lipoprotein, apolipoprotein levels, and content of cholesterol, cholesteryl ester, and triglycerides were measured after lipoprotein fractionation. Lipoprotein subclasses were analyzed by nuclear magnetic resonance. Apolipoprotein affinity for human arterial proteoglycans (PG) was measured. Biomarkers of cholesterol biosynthesis and intestinal absorption and bile lipid composition were analyzed using mass spectrometry. Combined treatment caused a statistically significant decrease in plasma remnant particles and apolipoprotein B (ApoB)/lipoprotein content of cholesterol, cholesteryl esters, and triglycerides. All treatments reduced ApoB‐lipoprotein PG binding. Simvastatin and combined treatment modified the composition of lipoproteins. Changes in biomarkers of cholesterol synthesis and absorption and bile acid synthesis were as expected. No adverse events were found. Conclusions Combined treatment caused atheroprotective changes on ApoB‐lipoproteins, remnant particles, bile components, and in ApoB‐lipoprotein affinity for arterial PG. These effects might explain the decrease of cardiovascular events seen in the SHARP and IMPROVE‐IT trials. Clinical Trial Registration URL: www.clinicaltrialsregister.eu. Unique identifier: 2006‐004839‐30).
Collapse
Affiliation(s)
- Osman Ahmed
- 1 Division of Clinical Chemistry Department of Laboratory Medicine Karolinska Institutet Stockholm Sweden.,2 Department of Biochemistry Faculty of Medicine Khartoum University Khartoum Sudan
| | - Karin Littmann
- 1 Division of Clinical Chemistry Department of Laboratory Medicine Karolinska Institutet Stockholm Sweden.,3 Function Area Clinical Chemistry Karolinska University Laboratory Function Karolinska University Hospital Stockholm Sweden
| | - Ulf Gustafsson
- 5 Department of Surgery Karolinska Institutet at Danderyd Hospital Stockholm Sweden
| | - Camilla Pramfalk
- 1 Division of Clinical Chemistry Department of Laboratory Medicine Karolinska Institutet Stockholm Sweden
| | | | - Lilian Larsson
- 1 Division of Clinical Chemistry Department of Laboratory Medicine Karolinska Institutet Stockholm Sweden
| | - Mirko E Minniti
- 1 Division of Clinical Chemistry Department of Laboratory Medicine Karolinska Institutet Stockholm Sweden
| | - Staffan Sahlin
- 5 Department of Surgery Karolinska Institutet at Danderyd Hospital Stockholm Sweden
| | - German Camejo
- 1 Division of Clinical Chemistry Department of Laboratory Medicine Karolinska Institutet Stockholm Sweden
| | - Paolo Parini
- 1 Division of Clinical Chemistry Department of Laboratory Medicine Karolinska Institutet Stockholm Sweden.,4 Patient Area Endocrinology and Nephrology, Inflammation and Infection Theme Karolinska University Hospital Stockholm Sweden.,7 Metabolism Unit Department of Medicine Karolinska Institutet at Karolinska University Hospital Huddinge Stockholm Sweden
| | - Mats Eriksson
- 4 Patient Area Endocrinology and Nephrology, Inflammation and Infection Theme Karolinska University Hospital Stockholm Sweden.,7 Metabolism Unit Department of Medicine Karolinska Institutet at Karolinska University Hospital Huddinge Stockholm Sweden
| |
Collapse
|
11
|
Rivas-Urbina A, Rull A, Ordóñez-Llanos J, Sánchez-Quesada JL. Electronegative LDL: An Active Player in Atherogenesis or a By- Product of Atherosclerosis? Curr Med Chem 2019; 26:1665-1679. [PMID: 29600751 DOI: 10.2174/0929867325666180330093953] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 11/12/2017] [Accepted: 12/11/2017] [Indexed: 12/16/2022]
Abstract
Low-density lipoproteins (LDLs) are the major plasma carriers of cholesterol. However, LDL particles must undergo various molecular modifications to promote the development of atherosclerotic lesions. Modified LDL can be generated by different mechanisms, but as a common trait, show an increased electronegative charge of the LDL particle. A subfraction of LDL with increased electronegative charge (LDL(-)), which can be isolated from blood, exhibits several pro-atherogenic characteristics. LDL(-) is heterogeneous, due to its multiple origins but is strongly related to the development of atherosclerosis. Nevertheless, the implication of LDL(-) in a broad array of pathologic conditions is complex and in some cases anti-atherogenic LDL(-) properties have been reported. In fact, several molecular modifications generating LDL(-) have been widely studied, but it remains unknown as to whether these different mechanisms are specific or common to different pathological disorders. In this review, we attempt to address these issues examining the most recent findings on the biology of LDL(-) and discussing the relationship between this LDL subfraction and the development of different diseases with increased cardiovascular risk. Finally, the review highlights the importance of minor apolipoproteins associated with LDL(-) which would play a crucial role in the different properties displayed by these modified LDL particles.
Collapse
Affiliation(s)
- Andrea Rivas-Urbina
- Cardiovascular Biochemistry Group, Research Institute of the Hospital de Sant Pau (IIB Sant Pau), Barcelona, Spain.,Biochemistry and Molecular Biology Department, Universitat Autònoma de Barcelona, Cerdanyola, Spain
| | - Anna Rull
- Cardiovascular Biochemistry Group, Research Institute of the Hospital de Sant Pau (IIB Sant Pau), Barcelona, Spain.,Hospital Universitari Joan XXIII, IISPV, Universitat Rovira i Virgili, Tarragona, Spain
| | - Jordi Ordóñez-Llanos
- Cardiovascular Biochemistry Group, Research Institute of the Hospital de Sant Pau (IIB Sant Pau), Barcelona, Spain.,Biochemistry and Molecular Biology Department, Universitat Autònoma de Barcelona, Cerdanyola, Spain
| | - José Luis Sánchez-Quesada
- Cardiovascular Biochemistry Group, Research Institute of the Hospital de Sant Pau (IIB Sant Pau), Barcelona, Spain.,CIBERDEM. Institute of Health Carlos III, Madrid 28029, Spain
| |
Collapse
|
12
|
Ligi D, Benitez S, Croce L, Rivas-Urbina A, Puig N, Ordóñez-Llanos J, Mannello F, Sanchez-Quesada JL. Electronegative LDL induces MMP-9 and TIMP-1 release in monocytes through CD14 activation: Inhibitory effect of glycosaminoglycan sulodexide. Biochim Biophys Acta Mol Basis Dis 2018; 1864:3559-3567. [PMID: 30254012 DOI: 10.1016/j.bbadis.2018.09.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 09/03/2018] [Accepted: 09/17/2018] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Electronegative LDL (LDL(-)) is involved in atherosclerosis through the activation of the TLR4/CD14 inflammatory pathway in monocytes. Matrix metalloproteinases (MMP) and their inhibitors (tissue inhibitors of metalloproteinase [TIMP]) are also crucially involved in atherosclerosis, but their modulation by LDL(-) has never been investigated. The aim of this study was to examine the ability of LDL(-) to release MMPs and TIMPs in human monocytes and to determine whether sulodexide (SDX), a glycosaminoglycan-based drug, was able to affect their secretion. APPROACH AND RESULTS Native LDL (LDL(+)) and LDL(-) separated by anion-exchange chromatography were added to THP1-CD14 monocytes in the presence or absence of SDX for 24 h. A panel of 9 MMPs and 4 TIMPs was analyzed in cell supernatants with multiplex immunoassays. The gelatinolytic activity of MMP-9 was assessed by gelatin zymography. LDL(-) stimulated the release of MMP-9 (13-fold) and TIMP-1 (4-fold) in THP1-CD14 monocytes, as well as the gelatinolytic activity of MMP-9. Co-incubation of monocytes with LDL(-) and SDX for 24 h significantly reduced both the release of MMP-9 and TIMP-1 and gelatinase activity. In THP1 cells not expressing CD14, no effect of LDL(-) on MMP-9 or TIMP-1 release was observed. The uptake of DiI-labeled LDL(-) was higher than that of DiI-LDL(+) in THP1-CD14 but not in THP1 cells. This increase was inhibited by SDX. Experiments in microtiter wells coated with SDX demonstrated a specific interaction of LDL(-) with SDX. CONCLUSIONS LDL(-) induced the release of MMP-9 and TIMP-1 in monocytes through CD14. SDX affects the ability of LDL(-) to promote TIMP-1 and MMP-9 release by its interaction with LDL(-).
Collapse
Affiliation(s)
- Daniela Ligi
- Department of Biomolecular Sciences, Section of Clinical Biochemistry and Molecular Genetics, University Carlo Bo Urbino, Italy
| | - Sonia Benitez
- Cardiovascular Biochemistry, Biomedical Research Institute Sant Pau (IIB-Sant Pau), Barcelona, Spain, C/Sant Antoni M. Claret 167, 08025 Barcelona, Spain; Molecular Biology and Biochemistry Department, Universitat Autònoma de Barcelona (UAB). Cerdanyola del Vallès, Spain
| | - Lidia Croce
- Department of Biomolecular Sciences, Section of Clinical Biochemistry and Molecular Genetics, University Carlo Bo Urbino, Italy
| | - Andrea Rivas-Urbina
- Cardiovascular Biochemistry, Biomedical Research Institute Sant Pau (IIB-Sant Pau), Barcelona, Spain, C/Sant Antoni M. Claret 167, 08025 Barcelona, Spain; Molecular Biology and Biochemistry Department, Universitat Autònoma de Barcelona (UAB). Cerdanyola del Vallès, Spain
| | - Núria Puig
- Cardiovascular Biochemistry, Biomedical Research Institute Sant Pau (IIB-Sant Pau), Barcelona, Spain, C/Sant Antoni M. Claret 167, 08025 Barcelona, Spain; Molecular Biology and Biochemistry Department, Universitat Autònoma de Barcelona (UAB). Cerdanyola del Vallès, Spain
| | - Jordi Ordóñez-Llanos
- Cardiovascular Biochemistry, Biomedical Research Institute Sant Pau (IIB-Sant Pau), Barcelona, Spain, C/Sant Antoni M. Claret 167, 08025 Barcelona, Spain; Molecular Biology and Biochemistry Department, Universitat Autònoma de Barcelona (UAB). Cerdanyola del Vallès, Spain
| | - Ferdinando Mannello
- Department of Biomolecular Sciences, Section of Clinical Biochemistry and Molecular Genetics, University Carlo Bo Urbino, Italy.
| | - Jose Luis Sanchez-Quesada
- Cardiovascular Biochemistry, Biomedical Research Institute Sant Pau (IIB-Sant Pau), Barcelona, Spain, C/Sant Antoni M. Claret 167, 08025 Barcelona, Spain; CIBER of Diabetes and Metabolic Diseases (CIBERDEM).
| |
Collapse
|
13
|
ApoB-100 Lipoprotein Complex Formation with Intima Proteoglycans as a Cause of Atherosclerosis and Its Possible Ex Vivo Evaluation as a Disease Biomarker. J Cardiovasc Dev Dis 2018; 5:jcdd5030036. [PMID: 29966388 PMCID: PMC6162553 DOI: 10.3390/jcdd5030036] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 06/27/2018] [Accepted: 06/28/2018] [Indexed: 12/22/2022] Open
Abstract
Experimental and clinical data indicate that the initiation and progress of atherosclerosis and its clinical manifestations are first caused by circulating apoB-100 lipoproteins that enter and are retained in the arterial intima. Extracellular sulfated proteoglycans (PGs) of the intima are the retention agents. The PGs also initiate physical and biochemical lipoprotein degradation with the production of bioactive, lipid products that trigger an inflammatory response that leads to atherosclerosis. There are many simple methods for measuring abnormalities of circulating lipoproteins and their relation to atherosclerotic cardiovascular disease (ACVD). However, limited research aims to evaluate procedures that could report quantitatively about the contribution of the interaction of apoB-100 lipoprotein-arterial intima PGs to clinical manifestation of ACVD. In the present review we discuss observations indicating that simple ex vivo evaluation of the affinity of apoB-100 lipoproteins for arterial PGs and glycosaminoglycans (GAGs) can give an indication of its association with clinical manifestations of atherosclerosis. In addition, we discuss molecular and cellular aspects of the apoB-100 lipoproteins association with arterial PGs that are related to atherogenesis and that support the experimental framework behind the current “Response-to-Retention” hypothesis of atherosclerosis.
Collapse
|
14
|
Thermal stability of human plasma electronegative low-density lipoprotein: A paradoxical behavior of low-density lipoprotein aggregation. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1015-1024. [PMID: 27233433 DOI: 10.1016/j.bbalip.2016.05.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 04/08/2016] [Accepted: 05/21/2016] [Indexed: 12/20/2022]
Abstract
Low-density lipoprotein (LDL) aggregation is central in triggering atherogenesis. A minor fraction of electronegative plasma LDL, termed LDL(-), plays a special role in atherogenesis. To better understand this role, we analyzed the kinetics of aggregation, fusion and disintegration of human LDL and its fractions, LDL(+) and LDL(-). Thermal denaturation of LDL was monitored by spectroscopy and electron microscopy. Initially, LDL(-) aggregated and fused faster than LDL(+), but later the order reversed. Most LDL(+) disintegrated and precipitated upon prolonged heating. In contrast, LDL(-) partially retained lipoprotein morphology and formed soluble aggregates. Biochemical analysis of all fractions showed no significant degradation of major lipids, mild phospholipid oxidation, and an increase in non-esterified fatty acid (NEFA) upon thermal denaturation. The main baseline difference between LDL subfractions was higher content of NEFA in LDL(-). Since NEFA promote lipoprotein fusion, increased NEFA content can explain rapid initial aggregation and fusion of LDL(-) but not its resistance to extensive disintegration. Partial hydrolysis of apoB upon heating was similar in LDL subfractions, suggesting that minor proteins importantly modulate LDL disintegration. Unlike LDL(+), LDL(-) contains small amounts of apoA-I and apoJ. Addition of exogenous apoA-I to LDL(+) hampered lipoprotein aggregation, fusion and precipitation, while depletion of endogenous apoJ had an opposite effect. Therefore, the initial rapid aggregation of LDL(-) is apparently counterbalanced by the stabilizing effects of minor proteins such as apoA-I and apoJ. These results help identify key determinants for LDL aggregation, fusion and coalescence into lipid droplets in vivo.
Collapse
|
15
|
Ke LY, Chan HC, Chen CC, Lu J, Marathe GK, Chu CS, Chan HC, Wang CY, Tung YC, McIntyre TM, Yen JH, Chen CH. Enhanced Sphingomyelinase Activity Contributes to the Apoptotic Capacity of Electronegative Low-Density Lipoprotein. J Med Chem 2016; 59:1032-40. [DOI: 10.1021/acs.jmedchem.5b01534] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Liang-Yin Ke
- Vascular
and Medicinal Research, Texas Heart Institute, Houston, Texas 77030, United States
| | - Hua-Chen Chan
- Vascular
and Medicinal Research, Texas Heart Institute, Houston, Texas 77030, United States
| | - Chih-Chieh Chen
- Institute
of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung, Taiwan 80424
| | - Jonathan Lu
- Vascular
and Medicinal Research, Texas Heart Institute, Houston, Texas 77030, United States
| | - Gopal K. Marathe
- Departments of Cellular & Molecular Medicine, Lerner Research Institute, Cleveland Clinic Lerner College of Medicine, Cleveland, Ohio 44195, United States
- Department
of Studies in Biochemistry, Manasagangothri, University of Mysore, Mysore-570006, India
| | | | | | | | | | - Thomas M. McIntyre
- Departments of Cellular & Molecular Medicine, Lerner Research Institute, Cleveland Clinic Lerner College of Medicine, Cleveland, Ohio 44195, United States
| | | | - Chu-Huang Chen
- Vascular
and Medicinal Research, Texas Heart Institute, Houston, Texas 77030, United States
- New York Heart Research
Foundation, Mineola, New York 11501, United States
| |
Collapse
|
16
|
Estruch M, Rajamäki K, Sanchez-Quesada JL, Kovanen PT, Öörni K, Benitez S, Ordoñez-Llanos J. Electronegative LDL induces priming and inflammasome activation leading to IL-1β release in human monocytes and macrophages. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:1442-9. [PMID: 26327597 DOI: 10.1016/j.bbalip.2015.08.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 08/05/2015] [Accepted: 08/26/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND Electronegative LDL (LDL(−)), a modified LDL fraction found in blood, induces the release of inflammatory mediators in endothelial cells and leukocytes. However, the inflammatory pathways activated by LDL(−) have not been fully defined. We aim to study whether LDL(−) induced release of the first-wave proinflammatory IL-1β in monocytes and monocyte-derived macrophages (MDM) and the mechanisms involved. METHODS LDL(−) was isolated from total LDL by anion exchange chromatography. Monocytes and MDM were isolated from healthy donors and stimulated with LDL(+) and LDL(−) (100 mg apoB/L). RESULTS In monocytes, LDL(−) promoted IL-1β release in a time-dependent manner, obtaining at 20 h-incubation the double of IL-1β release induced by LDL(−) than by native LDL. LDL(−)-induced IL-1β release involved activation of the CD14-TLR4 receptor complex. LDL(−) induced priming, the first step of IL-1β release, since it increased the transcription of pro-IL-1β (8-fold) and NLRP3 (3-fold) compared to native LDL. Several findings show that LDL(−) induced inflammasome activation, the second step necessary for IL-1β release. Preincubation of monocytes with K+ channel inhibitors decreased LDL(−)-induced IL-1β release. LDL(−) induced formation of the NLRP3-ASC complex. LDL(−) triggered 2-fold caspase-1 activation compared to native LDL and IL-1β release was strongly diminished in the presence of the caspase-1 inhibitor Z-YVAD. In MDM, LDL(−) promoted IL-1β release, which was also associated with caspase-1 activation. CONCLUSIONS LDL(−) promotes release of biologically active IL-1β in monocytes and MDM by induction of the two steps involved: priming and NLRP3 inflammasome activation. SIGNIFICANCE By IL-1β release, LDL(−) could regulate inflammation in atherosclerosis.
Collapse
Affiliation(s)
- M Estruch
- Biomedical Research Institute Sant Pau (IIB-Sant Pau), Barcelona (Spain). C/Sant Antoni M. Claret, 167 08025 Barcelona, Spain.
| | - K Rajamäki
- Wihuri Research Institute (WRI). Haartmaninkatu, 8 FI-00290 Helsinki, Finland.
| | - J L Sanchez-Quesada
- Biomedical Research Institute Sant Pau (IIB-Sant Pau), Barcelona (Spain). C/Sant Antoni M. Claret, 167 08025 Barcelona, Spain; Molecular Biology and Biochemistry Department, Universitat Autònoma de Barcelona (UAB) Faculty of Medicine, Building M. Cerdanyola del Vallès, Spain.
| | - P T Kovanen
- Wihuri Research Institute (WRI). Haartmaninkatu, 8 FI-00290 Helsinki, Finland.
| | - K Öörni
- Wihuri Research Institute (WRI). Haartmaninkatu, 8 FI-00290 Helsinki, Finland.
| | - S Benitez
- Biomedical Research Institute Sant Pau (IIB-Sant Pau), Barcelona (Spain). C/Sant Antoni M. Claret, 167 08025 Barcelona, Spain; Molecular Biology and Biochemistry Department, Universitat Autònoma de Barcelona (UAB) Faculty of Medicine, Building M. Cerdanyola del Vallès, Spain.
| | - J Ordoñez-Llanos
- Molecular Biology and Biochemistry Department, Universitat Autònoma de Barcelona (UAB) Faculty of Medicine, Building M. Cerdanyola del Vallès, Spain; Biochemistry Department. Hospital de la Santa Creu i Sant Pau Barcelona. C/Sant Quintí, 89 08026, Barcelona, Spain.
| |
Collapse
|
17
|
Ivanova EA, Bobryshev YV, Orekhov AN. LDL electronegativity index: a potential novel index for predicting cardiovascular disease. Vasc Health Risk Manag 2015; 11:525-32. [PMID: 26357481 PMCID: PMC4559248 DOI: 10.2147/vhrm.s74697] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
High cardiovascular risk conditions are frequently associated with altered plasma lipoprotein profile, such as elevated low-density lipoprotein (LDL) and LDL cholesterol and decreased high-density lipoprotein. There is, however, accumulating evidence that specific subclasses of LDL may play an important role in cardiovascular disease development, and their relative concentration can be regarded as a more relevant risk factor. LDL particles undergo multiple modifications in plasma that can lead to the increase of their negative charge. The resulting electronegative LDL [LDL(–)] subfraction has been demonstrated to be especially atherogenic, and became a subject of numerous recent studies. In this review, we discuss the physicochemical properties of LDL(–), methods of its detection, atherogenic activity, and relevance of the LDL electronegativity index as a potential independent predictor of cardiovascular risk.
Collapse
Affiliation(s)
- Ekaterina A Ivanova
- Department of Pediatric Nephrology and Growth and Regeneration, Katholieke Universiteit Leuven and University Hospitals Leuven, Leuven, Belgium
| | - Yuri V Bobryshev
- Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, Russian Academy of Sciences, Moscow, Russia ; Faculty of Medicine, School of Medical Sciences, University of New South Wales, Kensington, Sydney, NSW, Australia
| | - Alexander N Orekhov
- Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, Russian Academy of Sciences, Moscow, Russia ; Institute for Atherosclerosis Research, Skolkovo Innovative Center, Moscow, Russia ; Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia
| |
Collapse
|
18
|
|
19
|
Neufeld EB, Zadrozny LM, Phillips D, Aponte A, Yu ZX, Balaban RS. Decorin and biglycan retain LDL in disease-prone valvular and aortic subendothelial intimal matrix. Atherosclerosis 2014; 233:113-21. [PMID: 24529131 DOI: 10.1016/j.atherosclerosis.2013.12.038] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 11/25/2013] [Accepted: 12/03/2013] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Subendothelial LDL retention by intimal matrix proteoglycans is an initial step in atherosclerosis and calcific aortic valve disease. Herein, we identify decorin and biglycan as the proteoglycans that preferentially retain LDL in intimal matrix at disease-prone sites in normal valve and vessel wall. METHODS The porcine aortic valve and renal artery ostial diverter, initiation sites of calcific valve disease and renal atherosclerosis, respectively, from normal non-diseased animals were used as models in these studies. RESULTS Fluorescent human LDL was selectively retained on the lesion-prone collagen/proteoglycan-enriched aortic surface of the valve, where the elastic lamina is depleted, as previously observed in lesion-prone sites in the renal ostium. iTRAQ mass spectrometry of valve and diverter protein extracts identified decorin and biglycan as the major subendothelial intimal matrix proteoglycans electrostatically retained on human LDL affinity columns. Decorin levels correlated with LDL binding in lesion-prone sites in both tissues. Collagen binding to LDL was shown to be proteoglycan-mediated. All known basement membrane proteoglycans bound LDL suggesting they may modulate LDL uptake into the subendothelial matrix. The association of purified decorin with human LDL in an in vitro microassay was blocked by serum albumin and heparin suggesting anti-atherogenic roles for these proteins in vivo. CONCLUSIONS LDL electrostatic interactions with decorin and biglycan in the valve leaflets and vascular wall is a major source of LDL retention. The complementary electrostatic sites on LDL or these proteoglycans may provide a novel therapeutic target for preventing one of the earliest events in these cardiovascular diseases.
Collapse
Affiliation(s)
- Edward B Neufeld
- Laboratory of Cardiac Energetics, NHLBI, NIH, Bethesda, MD 20892, USA.
| | - Leah M Zadrozny
- Laboratory of Cardiac Energetics, NHLBI, NIH, Bethesda, MD 20892, USA
| | - Darci Phillips
- Laboratory of Cardiac Energetics, NHLBI, NIH, Bethesda, MD 20892, USA
| | - Angel Aponte
- Proteomics Core, NHLBI, NIH, Bethesda, MD 20892, USA
| | - Zu-Xi Yu
- Pathology Core, NHLBI, NIH, Bethesda, MD 20892, USA
| | - Robert S Balaban
- Laboratory of Cardiac Energetics, NHLBI, NIH, Bethesda, MD 20892, USA
| |
Collapse
|
20
|
Kaya K, Işıkgil, Güldür T. Comparison of hydrophobic properties of thoracic duct lymph chylomicrons from rats given different fats or oils by gavage. J Anim Physiol Anim Nutr (Berl) 2013; 98:587-95. [PMID: 24112055 DOI: 10.1111/jpn.12127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 07/26/2013] [Indexed: 11/29/2022]
Abstract
Lipoprotein aggregation is generated by hydrophobic nature of lipoproteins that is known to be one of the causes of atherosclerosis. Low density lipoproteins (LDL) has been extensively studied in this respect but not chylomicrons. There is strong evidence that post-prandial triacylglycerol-rich lipoproteins are atherogenic. Because biophysical properties of lipoproteins are largely determined by their lipid compositions, hydrophobic nature of thoracic lymph duct chylomicrons obtained from rats given different fats or oils by gavage was investigated by vortexing-induced aggregation and hydrophobic interaction chromatography. Contrary to LDL, vortexing did not cause aggregation in chylomicrons. Vortexing of fish oil and butter chylomicrons resulted in more prominent reduction in absorbances compared with chylomicrons from other sources that might indicate less micelle stability. Hydrophobic interaction chromatography of fish oil, palm oil and olive oil chylomicrons yielded three fractions, whereas that of sunflower, margarine and butter chylomicrons gave rise to two fractions. These results suggest that surface hydrophobicity of chylomicrons might be heterogenous. Our results also demonstrate that fish oil chylomicrons have less hydrophobicity and lower stability against vortexing compared with chylomicrons from other sources. Considering beneficial effects of fish oil in cardiovascular health, less hydrophobicity together with lower stability might provide an additional atherogeneicity index for lipoproteins.
Collapse
Affiliation(s)
- K Kaya
- Department of Medical Biochemistry, Graduate Institute of Health Sciences, İnönü University, Malatya, Turkey
| | | | | |
Collapse
|
21
|
The Induction of Cytokine Release in Monocytes by Electronegative Low-Density Lipoprotein (LDL) Is Related to Its Higher Ceramide Content than Native LDL. Int J Mol Sci 2013; 14:2601-16. [PMID: 23358250 PMCID: PMC3588005 DOI: 10.3390/ijms14022601] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 01/05/2013] [Accepted: 01/16/2013] [Indexed: 12/21/2022] Open
Abstract
Electronegative low-density lipoprotein (LDL(−)) is a minor modified LDL subfraction that is present in blood. LDL(−) promotes inflammation and is associated with the development of atherosclerosis. We previously reported that the increase of cytokine release promoted by this lipoprotein subfraction in monocytes is counteracted by high-density lipoprotein (HDL). HDL also inhibits a phospholipase C-like activity (PLC-like) intrinsic to LDL(−). The aim of this work was to assess whether the inhibition of the PLC-like activity by HDL could decrease the content of ceramide (CER) and diacylglycerol (DAG) generated in LDL(−). This knowledge would allow us to establish a relationship between these compounds and the inflammatory activity of LDL(−). LDL(−) incubated at 37 °C for 20 h increased its PLC-like activity and, subsequently, the amount of CER and DAG. We found that incubating LDL(−) with HDL decreased both products in LDL(−). Native LDL was modified by lipolysis with PLC or by incubation with CER-enriched or DAG-enriched liposomes. The increase of CER in native LDL significantly increased cytokine release, whereas the enrichment in DAG did not show these inflammatory properties. These data point to CER, a resultant product of the PLC-like activity, as a major determinant of the inflammatory activity induced by LDL(−) in monocytes.
Collapse
|
22
|
Sánchez-Quesada JL, Villegas S, Ordóñez-Llanos J. Electronegative low-density lipoprotein. A link between apolipoprotein B misfolding, lipoprotein aggregation and proteoglycan binding. Curr Opin Lipidol 2012; 23:479-86. [PMID: 22964994 DOI: 10.1097/mol.0b013e328357c933] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW Subendothelial retention of lipoproteins is considered the first step in the development of atherosclerosis, but the molecular mechanisms involved are poorly understood. Recent findings on the atherogenic properties of a minor electronegative fraction of LDL (LDL(-)) could contribute to a better understanding of this process. RECENT FINDINGS Circular dichroism, Trp-fluorescence and two-dimensional nuclear magnetic resonance have shown that apolipoprotein B (apoB) in LDL(-) has an abnormal, misfolded conformation. Immunochemical analysis revealed a different conformation, mainly in the N-terminal and C-terminal extremes. These alterations contribute to the high susceptibility to aggregation of LDL(-). Moreover, LDL(-) can seed the aggregation of native LDL, suggesting an amyloidogenic character that has been attributed to the amphipathic helix cluster in the α2-domain. A phospholipase C (PLC)-like activity associated to LDL(-) seems to play a major role in the LDL(-)-induced aggregation. The aggregation of LDL(-) increases its binding to proteoglycans because of the abnormal conformation of the N-terminal extreme of apoB. SUMMARY LDL(-) could play a relevant role in atherogenesis by acting as a priming factor that stimulates lipoprotein aggregation. This process, which appears to be mediated by a PLC-like activity intrinsic to LDL(-), increases the binding of LDL to proteoglycans and could promote subendothelial retention of these lipoproteins.
Collapse
Affiliation(s)
- José L Sánchez-Quesada
- Biochemistry Department, Biomedical Research Institute Sant Pau (IIB Sant Pau), Barcelona, Spain.
| | | | | |
Collapse
|
23
|
Melnichenko AA, Aksenov DV, Myasoedova VA, Panasenko OM, Yaroslavov AA, Sobenin IA, Bobryshev YV, Orekhov AN. Pluronic block copolymers inhibit low density lipoprotein self-association. Lipids 2012; 47:995-1000. [PMID: 22797973 DOI: 10.1007/s11745-012-3699-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Accepted: 06/28/2012] [Indexed: 01/30/2023]
Abstract
Little is known about exogenous inhibitors of low-density lipoprotein (LDL) aggregation. The search for nontoxic and bioavailable inhibitors of LDL aggregation is of interest, especially considering that the suppression of the aggregation of LDL might represent a therapeutic approach. We hypothesized that amphiphilic copolymers of propylene oxide and ethylene oxide, the so-called Pluronic block copolymers, can be used to influence the aggregation of LDL. In this work we used Pluronic® P85, L61 and F68. A comparative study of the effects of Pluronic block copolymers with various hydrophilic-lipophilic properties on the aggregation process of LDL showed that Pluronic copolymers with strong hydrophobic properties (P85 and L61) at concentrations close to or greater than the respective critical concentration of micelle formation inhibited the aggregation process of LDL; however, the "hydrophilic" Pluronic F68 had no effect on the aggregation of LDL at any concentration. Thus, the study demonstrated for the first time that Pluronic® block copolymers inhibit LDL self-association. The possibility of modulating the aggregation of LDL by various Pluronic copolymers can be regarded as a prerequisite in the creation of new types of anti-atherosclerotic drugs.
Collapse
Affiliation(s)
- Alexandra A Melnichenko
- Institute of General Pathology and Pathophysiology, Russian Academy of Medical Sciences, Moscow, Russia
| | | | | | | | | | | | | | | |
Collapse
|
24
|
Sánchez-Quesada JL, Estruch M, Benítez S, Ordóñez-Llanos J. Electronegative LDL: a useful biomarker of cardiovascular risk? ACTA ACUST UNITED AC 2012. [DOI: 10.2217/clp.12.26] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
25
|
Electronegative low-density lipoprotein: Origin and impact on health and disease. Atherosclerosis 2011; 215:257-65. [DOI: 10.1016/j.atherosclerosis.2010.12.028] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 11/25/2010] [Accepted: 12/30/2010] [Indexed: 11/17/2022]
|
26
|
Anggraeni VY, Emoto N, Yagi K, Mayasari DS, Nakayama K, Izumikawa T, Kitagawa H, Hirata KI. Correlation of C4ST-1 and ChGn-2 expression with chondroitin sulfate chain elongation in atherosclerosis. Biochem Biophys Res Commun 2011; 406:36-41. [DOI: 10.1016/j.bbrc.2011.01.096] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Accepted: 01/26/2011] [Indexed: 10/18/2022]
|
27
|
Bancells C, Benítez S, Ordóñez-Llanos J, Öörni K, Kovanen PT, Milne RW, Sánchez-Quesada JL. Immunochemical analysis of the electronegative LDL subfraction shows that abnormal N-terminal apolipoprotein B conformation is involved in increased binding to proteoglycans. J Biol Chem 2010; 286:1125-33. [PMID: 21078674 DOI: 10.1074/jbc.m110.175315] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Electronegative LDL (LDL(-)) is a minor subfraction of modified LDL present in plasma. Among its atherogenic characteristics, low affinity to the LDL receptor and high binding to arterial proteoglycans (PGs) could be related to abnormalities in the conformation of its main protein, apolipoprotein B-100 (apoB-100). In the current study, we have performed an immunochemical analysis using monoclonal antibody (mAb) probes to analyze the conformation of apoB-100 in LDL(-). The study, performed with 28 anti-apoB-100 mAbs, showed that major differences of apoB-100 immunoreactivity between native LDL and LDL(-) concentrate in both terminal extremes. The mAbs Bsol 10, Bsol 14 (which recognize the amino-terminal region), Bsol 2, and Bsol 7 (carboxyl-terminal region) showed increased immunoreactivity in LDL(-), suggesting that both terminal extremes are more accessible in LDL(-) than in native LDL. The analysis of in vitro-modified LDLs, including LDL lipolyzed with sphingomyelinase (SMase-LDL) or phospholipase A(2) (PLA(2)-LDL) and oxidized LDL (oxLDL), suggested that increased amino-terminal immunoreactivity was related to altered conformation due to aggregation. This was confirmed when the aggregated subfractions of LDL(-) (agLDL(-)) and oxLDL (ag-oxLDL) were isolated and analyzed. Thus, Bsol 10 and Bsol 14 immunoreactivity was high in SMase-LDL, ag-oxLDL, and agLDL(-). The altered amino-terminal apoB-100 conformation was involved in the increased PG binding affinity of agLDL(-) because Bsol 10 and Bsol 14 blocked its high PG-binding. These observations suggest that an abnormal conformation of the amino-terminal region of apoB-100 is responsible for the increased PG binding affinity of agLDL(-).
Collapse
Affiliation(s)
- Cristina Bancells
- Biochemistry Department, Biomedical Research Institute Sant Pau, Hospital de la Santa Creu i Sant Pau, 08025 Barcelona, Catalonia, Spain.
| | | | | | | | | | | | | |
Collapse
|
28
|
Bancells C, Villegas S, Blanco FJ, Benítez S, Gállego I, Beloki L, Pérez-Cuellar M, Ordóñez-Llanos J, Sánchez-Quesada JL. Aggregated electronegative low density lipoprotein in human plasma shows a high tendency toward phospholipolysis and particle fusion. J Biol Chem 2010; 285:32425-35. [PMID: 20670941 DOI: 10.1074/jbc.m110.139691] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Aggregation and fusion of lipoproteins trigger subendothelial retention of cholesterol, promoting atherosclerosis. The tendency of a lipoprotein to form fused particles is considered to be related to its atherogenic potential. We aimed to isolate and characterize aggregated and nonaggregated subfractions of LDL from human plasma, paying special attention to particle fusion mechanisms. Aggregated LDL was almost exclusively found in electronegative LDL (LDL(-)), a minor modified LDL subfraction, but not in native LDL (LDL(+)). The main difference between aggregated (agLDL(-)) and nonaggregated LDL(-) (nagLDL(-)) was a 6-fold increased phospholipase C-like activity in agLDL(-). agLDL(-) promoted the aggregation of LDL(+) and nagLDL(-). Lipoprotein fusion induced by α-chymotrypsin proteolysis was monitored by NMR and visualized by transmission electron microscopy. Particle fusion kinetics was much faster in agLDL(-) than in nagLDL(-) or LDL(+). NMR and chromatographic analysis revealed a rapid and massive phospholipid degradation in agLDL(-) but not in nagLDL(-) or LDL(+). Choline-containing phospholipids were extensively degraded, and ceramide, diacylglycerol, monoacylglycerol, and phosphorylcholine were the main products generated, suggesting the involvement of phospholipase C-like activity. The properties of agLDL(-) suggest that this subfraction plays a major role in atherogenesis by triggering lipoprotein fusion and cholesterol accumulation in the arterial wall.
Collapse
Affiliation(s)
- Cristina Bancells
- Departament de Bioquímica, Institut d'Investigacions Biomèdiques Sant Pau, Hospital de la Santa Creu i Sant Pau, 08025 Barcelona, Spain
| | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Bancells C, Sánchez-Quesada JL, Birkelund R, Ordóñez-Llanos J, Benítez S. HDL and electronegative LDL exchange anti- and pro-inflammatory properties. J Lipid Res 2010; 51:2947-56. [PMID: 20647593 DOI: 10.1194/jlr.m005777] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Electronegative LDL [LDL(-)] is a minor modified LDL subfraction present in blood with inflammatory effects. One of the antiatherogenic properties of HDL is the inhibition of the deleterious effects of in vitro modified LDL. However, the effect of HDL on the inflammatory activity of LDL(-) isolated from plasma is unknown. We aimed to assess the putative protective role of HDL against the cytokine released induced in monocytes by LDL(-). Our results showed that LDL(-) cytokine release was inhibited when LDL(-) was coincubated with HDL and human monocytes and also when LDL(-) was preincubated with HDL and reisolated prior to cell incubation. The addition of apoliprotein (apo)AI instead of HDL reproduced the protective behavior of HDL. HDL preincubated with LDL(-) promoted greater cytokine release than native HDL. Incubation of LDL(-) with HDL decreased the electronegative charge, phospholipase C-like activity, susceptibility to aggregation and nonesterified fatty acid (NEFA) content of LDL(-), whereas these properties increased in HDL. NEFA content in LDL appeared to be related to cytokine production because NEFA-enriched LDL induced cytokine release. HDL, at least in part through apoAI, inhibits phospholipase-C activity and cytokine release in monocytes, thereby counteracting the inflammatory effect of LDL(-). In turn, HDL acquires these properties and becomes inflammatory.
Collapse
Affiliation(s)
- Cristina Bancells
- Institut de Recerca, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | | | | | | | | |
Collapse
|