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Taylor JA, Hutchinson MA, Gearhart PJ, Maul RW. Antibodies in action: the role of humoral immunity in the fight against atherosclerosis. Immun Ageing 2022; 19:59. [PMID: 36461105 PMCID: PMC9717479 DOI: 10.1186/s12979-022-00316-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 11/21/2022] [Indexed: 12/03/2022]
Abstract
The sequestering of oxidation-modified low-density lipoprotein by macrophages results in the accumulation of fatty deposits within the walls of arteries. Necrosis of these cells causes a release of intercellular epitopes and the activation of the adaptive immune system, which we predict leads to robust autoantibody production. T cells produce cytokines that act in the plaque environment and further stimulate B cell antibody production. B cells in atherosclerosis meanwhile have a mixed role based on subclass. The current model is that B-1 cells produce protective IgM antibodies in response to oxidation-specific epitopes that work to control plaque formation, while follicular B-2 cells produce class-switched antibodies (IgG, IgA, and IgE) which exacerbate the disease. Over the course of this review, we discuss further the validation of these protective antibodies while evaluating the current dogma regarding class-switched antibodies in atherosclerosis. There are several contradictory findings regarding the involvement of class-switched antibodies in the disease. We hypothesize that this is due to antigen-specificity, and not simply isotype, being important, and that a closer evaluation of these antibodies' targets should be conducted. We propose that specific antibodies may have therapeutical potential in preventing and controlling plaque development within a clinical setting.
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Affiliation(s)
- Joshua A. Taylor
- grid.419475.a0000 0000 9372 4913Laboratory of Molecular Biology and Immunology, National Institute on Aging, NIH, Baltimore, MD USA ,grid.21107.350000 0001 2171 9311Graduate Program in Immunology, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Mark A. Hutchinson
- grid.419475.a0000 0000 9372 4913Laboratory of Molecular Biology and Immunology, National Institute on Aging, NIH, Baltimore, MD USA
| | - Patricia J. Gearhart
- grid.419475.a0000 0000 9372 4913Laboratory of Molecular Biology and Immunology, National Institute on Aging, NIH, Baltimore, MD USA
| | - Robert W. Maul
- grid.419475.a0000 0000 9372 4913Laboratory of Molecular Biology and Immunology, National Institute on Aging, NIH, Baltimore, MD USA
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Rehman S, Alouffi S, Faisal M, Qahtan AA, Alatar AA, Ahmad S. Methylglyoxal mediated glycation leads to neo-epitopes generation in fibrinogen: Role in the induction of adaptive immune response. Int J Biol Macromol 2021; 175:535-543. [PMID: 33529635 DOI: 10.1016/j.ijbiomac.2021.01.197] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 01/26/2021] [Accepted: 01/28/2021] [Indexed: 01/12/2023]
Abstract
In diabetes mellitus, hyperglycemia mediated non-enzymatic glycosylation of proteins results in the pathogenesis of diabetes-associated secondary complications via the generation of advanced glycation end products (AGEs). The focus of this study is to reveal the immunological aspects of methylglyoxal (MG) mediated glycation of fibrinogen protein. The induced immunogenicity of modified fibrinogen is analyzed by direct binding and inhibition ELISA. Direct binding ELISA confirmed that MG glycated fibrinogen (MG-Fib) is highly immunogenic and induces a high titer of antibodies in comparison to its native analog. Cross-reactivity and antigen-binding specificity of induced antibodies were confirmed by inhibition ELISA. The enhanced affinity of immunoglobulin G (IgG) from immunized rabbits' sera and MG glycated fibrinogen is probably the aftermath of neo-epitopes generation in the native structure of protein upon modification. Thus, we deduce that under the glycative stress, MG-mediated structural alterations in fibrinogen could induce the generation of antibodies which might serve as a potential biomarker in diabetes mellitus and its associated secondary disorders.
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Affiliation(s)
- Shahnawaz Rehman
- IIRC-1, Laboratory of Glycation Biology and Metabolic Disorder, Integral University, Lucknow, Uttar Prade sh-226026, India
| | - Sultan Alouffi
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, University of Hail, Saudi Arabia; Molecular Diagnostic & Personalized Therapeutic Unit, University of Hail, Saudi Arabia
| | - Mohammad Faisal
- Department of Botany and Microbiology, College of Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Ahmed A Qahtan
- Department of Botany and Microbiology, College of Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Abdulrahman A Alatar
- Department of Botany and Microbiology, College of Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Saheem Ahmad
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, University of Hail, Saudi Arabia.
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Lopes-Virella MF, Bebu I, Hunt KJ, Virella G, Baker NL, Braffett B, Gao X, Lachin JM. Immune Complexes and the Risk of CVD in Type 1 Diabetes. Diabetes 2019; 68:1853-1860. [PMID: 31217176 PMCID: PMC6702641 DOI: 10.2337/db19-0358] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 06/17/2019] [Indexed: 12/15/2022]
Abstract
We investigated whether the composition of modified forms of LDL in circulating immune complexes (LDL-ICs) was associated with cardiovascular disease (CVD) outcomes, including any CVD, major adverse cardiac and cerebrovascular events (MACCE), myocardial infarction (MI), and coronary artery disease, in type 1 diabetes (T1D). Our results demonstrate that the baseline levels of oxidized LDL (oxLDL), MDA-modified LDL (MDA-LDL), and advanced glycosylation-modified LDL (AGE-LDL) in circulating ICs were associated with the four CVD outcomes in unadjusted models, and adjustment by age and mean HbA1c only resulted in minimal reduction of these associations. After adjustments were made for other cardiovascular risk factors, particularly LDL cholesterol, oxLDL-IC and MDA-LDL-IC remained independently associated with the risk of CVD, and oxLDL-IC was independently associated with the risk of MACCE and MI. In the majority of cases, the baseline levels of modified LDL-IC (measured many years before the occurrence of any CVD event) were associated with the risk of CVD over a 25-year period even after adjustment for other risk factors (including LDL cholesterol). Therefore, modified LDL biomarkers may help identify patients with T1D at high risk for MACCE and CVD events very early in the evolution of the disease, before other signals of disease are apparent.
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Affiliation(s)
| | - Ionut Bebu
- Biostatistics Center, The George Washington University, Rockville, MD
| | - Kelly J Hunt
- Medical University of South Carolina, Charleston, SC
| | | | | | - Barbara Braffett
- Biostatistics Center, The George Washington University, Rockville, MD
| | - Xiaoyu Gao
- Biostatistics Center, The George Washington University, Rockville, MD
| | - John M Lachin
- Biostatistics Center, The George Washington University, Rockville, MD
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Lopes-Virella MF, Virella G. Modified LDL Immune Complexes and Cardiovascular Disease. Curr Med Chem 2019; 26:1680-1692. [DOI: 10.2174/0929867325666180524114429] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 11/17/2017] [Accepted: 12/28/2017] [Indexed: 12/17/2022]
Abstract
Modified forms of LDL, both spontaneously formed in the organism or prepared in the laboratory, are immunogenic. As a consequence, antigen-antibody complexes (immune complexes, IC) formed in vivo can be measured in the peripheral blood, and their levels are strong predictors of cardiovascular disease (CVD). It has been possible to generate antibodies that recognize different LDL modifications, allowing the analysis of circulating IC constitution. Clinical studies showed that the antigenic constitution of the IC has a modulating effect on the development of CVD. Patients whose IC react strongly with antibodies to copper oxidized LDL (oxLDL) show progressive development of atherosclerosis as demonstrated by increased intima–media thickness and increased coronary calcification scores. In contrast, patients whose IC react strongly with antibodies to the heavily oxidized malondialdehyde LDL prepared in vitro (MDA-LDL) are at a high risk of acute vascular events, mainly myocardial infarction. In vitro studies have shown that while oxLDL IC induce both cell proliferation and mild to moderate macrophage apoptosis, MDA-LDL IC induce a more marked macrophage apoptosis but not cell proliferation. In addition, MDA-LDL IC induce the release of higher levels of matrix metalloproteinases and TNF than oxLDL IC. High levels of TNF are likely to be a major factor leading to apoptosis and high levels of metalloproteinases are likely to play a role in the thinning of the fibrous cap of the atheromatous plaque. The combination of apoptosis and fibrous cap thinning is a well-known characteristic of vulnerable plaques, which are more prone to rupture and responsible for the majority of acute cardiovascular events.
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Affiliation(s)
- Maria F. Lopes-Virella
- Department of Medicine, Medical University of South Carolina, Charleston, SC, USA; Ralph A. Johnson VA Medical Center, Charleston, SC, United States
| | - Gabriel Virella
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, United States
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Immunochemical studies on native and glycated LDL – An approach to uncover the structural perturbations. Int J Biol Macromol 2018; 115:287-299. [DOI: 10.1016/j.ijbiomac.2018.04.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 03/20/2018] [Accepted: 04/04/2018] [Indexed: 01/27/2023]
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Immune complexes containing malondialdehyde (MDA) LDL induce apoptosis in human macrophages. Clin Immunol 2018; 187:1-9. [DOI: 10.1016/j.clim.2017.06.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 06/27/2017] [Accepted: 06/27/2017] [Indexed: 11/22/2022]
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A Method for In Vitro Measurement of Oxidized Low-Density Lipoprotein in Blood, Using Its Antibody, Fluorescence-Labeled Heptapeptide and Polyethylene Glycol. J Fluoresc 2017; 27:1985-1993. [DOI: 10.1007/s10895-017-2137-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 06/30/2017] [Indexed: 01/15/2023]
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Anti-Ro and Concomitant Anti-La Autoantibodies Strongly Associated With Anti-oxLDL or Anti-Phospholipid Antibody in Systemic Lupus Erythematosus. J Clin Rheumatol 2016; 22:418-425. [PMID: 27870764 DOI: 10.1097/rhu.0000000000000429] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Premature atherosclerosis is observed in systemic lupus erythematosus (SLE). Oxidative modification of LDL is associated with atherosclerotic plaque formation. OBJECTIVES We hypothesized that anti-oxidized LDL (oxLDL) and anti-phospholipid (APL) in SLE sera would segregate with specific antibody subsets, and that anti-oxLDL antibodies will linger in circulation over an extended period. PATIENTS AND METHODS Sixty-seven SLE and control subjects and two SLE subjects with sera collected longitudinally for 13 years were tested for anti-oxLDL and IgG/IgM/IgA APL antibodies. RESULTS Anti-oxLDL ELISA values above 57.48 Activity Units (AcU) (means of normals + 3 standard deviations) and anti-IgG/IgM/IgA APL above 10 phospholipid units (PU) were considered positive. Average anti-oxLDL was 67.7 ± 50.5 AcU in SLE compared to 23.9 ± 11.19 AcU in normals (P = 0.018). Ten out of ten subjects with anti-Ro60/anti-La/anti-Ro52 antibodies had highly significant (P < 0.0001) anti-oxLDL (127.29 ± 45.67 AcU) and IgG APL (18.66 ± 7.4 PU) (P < 0.02). Subjects with anti-RNP were positive for anti-oxLDL (P < 0.002), but subjects with anti-Ro60/anti-Ro52 and subjects negative for extractable nuclear antigen (ENA) antibody were not positive for anti-oxLDL. Anti-oxLDL/anti-IgG APL remained significantly elevated in two patients studied longitudinally. Interestingly, one developed anti-oxLDL/anti-APL antibodies several years before anti-Ro60 development. CONCLUSIONS Presence of antibodies against Ro RNP and La, and RNP is highly associated with developing anti-oxLDL and APL antibodies in SLE. It will be clinically important to see if cardiovascular events occur in these SLE subsets having elevated anti-oxLDL and APL antibodies. Emergence of anti-oxLDL/IgG APL before anti-Ro60 over time in a patient indicates that these antibodies could not be cross-reactive in nature, at least in this particular patient.
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The association between oxidized low-density lipoprotein antibodies and hematological diseases. Lipids Health Dis 2016; 15:190. [PMID: 27825356 PMCID: PMC5101799 DOI: 10.1186/s12944-016-0360-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 11/01/2016] [Indexed: 01/18/2023] Open
Abstract
Background The aim of the study is to compare the profiles of antibodies (IgM and IgG) against oxidized low-density lipoprotein (oxLDL) of hematological diseases. Methods The serum antibodies of oxLDL-IgM and oxLDL-IgG for 446 cases with hematological diseases and 90 patients with primary hypertension and 90 healthy controls were measured by enzyme-linked immunosorbent assay (ELISA) in a cross-section survey. The association of serum oxLDL-LgM and oxLDL-IgG with hematological diseases was analyzed by multiple linear regression model. Results Comparing with the hypertension or normal groups, the levels of TCH, TG, LDL-c, HDL-c, oxLDL, and oxLDL-IgG were lower and the levels of ADP and oxLDL-IgM were higher in the hematological diseases group. The levels of oxLDL-IgG antibodies titer were different among hematological diseases group. The results of correlation and multiple regression analysis showed that the seven hematological disease subgroups were positively related to the oxLDL-IgM antibody titer but negatively related to the oxLDL-IgG antibody titer, having been adjusted for potential confounding factors such as age, SBP, DBP, BMI, TCH, TG, ADP, oxLDL, HDL-c, LDL-C. Conclusions Here we show that oxLDL-IgG antibodies titer were lower and of oxLDL-IgM titer were higher than hypertension and healthy individuals. Also oxLDL-IgG titer were different among hematological diseases group.
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Lopes-Virella MF, Hunt KJ, Baker NL, Virella G. High levels of AGE-LDL, and of IgG antibodies reacting with MDA-lysine epitopes expressed by oxLDL and MDA-LDL in circulating immune complexes predict macroalbuminuria in patients with type 2 diabetes. J Diabetes Complications 2016; 30:693-9. [PMID: 26861948 DOI: 10.1016/j.jdiacomp.2016.01.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Revised: 01/11/2016] [Accepted: 01/12/2016] [Indexed: 02/03/2023]
Abstract
BACKGROUND Circulating immune complexes (IC) containing modified forms of LDL (mLDL) are strongly pro-inflammatory and when present in high levels are associated with the development of diabetic complications. OBJECTIVE We investigated whether levels of oxidized LDL (oxLDL), malondialdehyde-LDL (MDA-LDL) and advanced glycation end products-LDL (AGE-LDL) as well as IgG and IgM antibodies reacting with MDA-lysine epitopes expressed by oxLDL and MDA-LDL isolated from circulating IC were associated with progression to macroalbuminuria in type 2 diabetes (VADT cohort). METHODS Levels of mLDL in IC were measured in 905 patients, a median of two years after entry into the study. Participants were followed for an average of 3.7years for renal outcomes. Generalized logistic regression models were used to quantify the association of increased levels of biomarkers and development of abnormal albuminuria. Normal, persistent micro- (ACR ≥30), incident micro- (ACR ≥30) and incident macroalbuminuria (ACR ≥300) were the outcomes of interest. RESULTS AND CONCLUSIONS Patients with macro (n=78) or non-persistent microalbuminuria (n=81) at baseline were excluded. Odds ratios for endpoints in relation to high versus low (defined using a median split) biomarker levels are found in Fig. 1. Our study demonstrates that high levels of AGE-LDL as well as of IgG antibodies (but not IgM antibodies) reacting with MDA-LDL lysine epitopes in circulating IC predict the development of macroalbuminuria in patients with type 2 diabetes. These data support the pathogenic role of modified LDL IgG antibodies but not the protective role of modified LDL IgM antibodies.
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Affiliation(s)
- Maria F Lopes-Virella
- Department of Medicine and Laboratory Services, Medical University of South Carolina and Ralph H. Johnson VA Medical Center, Charleston, SC.
| | - Kelly J Hunt
- Department of Public Health Services, Medical University of South Carolina, Charleston, SC
| | - Nathaniel L Baker
- Department of Public Health Services, Medical University of South Carolina, Charleston, SC
| | - Gabriel Virella
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC
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Akhter F, Khan MS, Alatar AA, Faisal M, Ahmad S. Antigenic role of the adaptive immune response to d -ribose glycated LDL in diabetes, atherosclerosis and diabetes atherosclerotic patients. Life Sci 2016; 151:139-146. [DOI: 10.1016/j.lfs.2016.02.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 12/28/2015] [Accepted: 02/05/2016] [Indexed: 12/15/2022]
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Tsekovska R, Sredovska-Bozhinov A, Niwa T, Ivanov I, Mironova R. Maillard reaction and immunogenicity of protein therapeutics. World J Immunol 2016; 6:19-38. [DOI: 10.5411/wji.v6.i1.19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Revised: 11/24/2015] [Accepted: 12/14/2015] [Indexed: 02/05/2023] Open
Abstract
The recombinant DNA technology enabled the production of a variety of human therapeutic proteins. Accumulated clinical experience, however, indicates that the formation of antibodies against such proteins is a general phenomenon rather than an exception. The immunogenicity of therapeutic proteins results in inefficient therapy and in the development of undesired, sometimes life-threatening, side reactions. The human proteins, designed for clinical application, usually have the same amino acid sequence as their native prototypes and it is not yet fully clear what the reasons for their immunogenicity are. In previous studies we have demonstrated for the first time that interferon-β (IFN-β) pharmaceuticals, used for treatment of patients with multiple sclerosis, do contain advanced glycation end products (AGEs) that contribute to IFN-β immunogenicity. AGEs are the final products of a chemical reaction known as the Maillard reaction or glycation, which implication in protein drugs’ immunogenicity has been overlooked so far. Therefore, the aim of the present article is to provide a comprehensive overview on the Maillard reaction with emphasis on experimental data and theoretical consideration telling us why the Maillard reaction warrants special attention in the context of the well-documented protein drugs’ immunogenicity.
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Abstract
The mechanisms or causes of pancreatic β-cell death as well as impaired insulin secretion, which are the principal events of diabetic etiopathology, are largely unknown. Diabetic complications are known to be associated with abnormal plasma lipid profile, mainly elevated level of cholesterol and free fatty acids. However, in recent years, elevated plasma cholesterol has been implicated as a primary modulator of pancreatic β-cell functions as well as death. High-cholesterol diet in animal models or excess cholesterol in pancreatic β-cell causes transporter desensitization and results in morphometric changes in insulin granules. Moreover, cholesterol is also held responsible to cause oxidative stress, mitochondrial dysfunction, and activation of proapoptotic markers leading to β-cell death. The present review focuses on the pathways and molecularevents that occur in the β-cell under the influence of excess cholesterol that hampers the basal physiology of the cell leading to the progression of diabetes.
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Vavuli S, Salonurmi T, Loukovaara S, Nissinen AE, Savolainen MJ, Liinamaa MJ. Elevated Levels of Plasma IgA Autoantibodies against Oxidized LDL Found in Proliferative Diabetic Retinopathy but Not in Nonproliferative Retinopathy. J Diabetes Res 2016; 2016:2614153. [PMID: 28090539 PMCID: PMC5206457 DOI: 10.1155/2016/2614153] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 11/10/2016] [Accepted: 11/28/2016] [Indexed: 01/08/2023] Open
Abstract
Aims. This study investigated the association of autoantibodies binding to oxidized low-density lipoproteins (oxLDL) in diabetic retinopathy (DR). Methods. Plasma from 229 types 1 and 2 patients with DR including diabetic macular edema (DME) and proliferative diabetic retinopathy (PDR) was analysed with ELISA-based assay to determine IgA, IgG, and IgM autoantibody levels binding to oxLDL. The controls were 106 diabetic patients without retinopathy (NoDR) and 139 nondiabetic controls (C). Results. PDR group had significantly higher IgA autoantibody levels than DME or NoDR: mean 94.9 (SD 54.7) for PDR, 75.5 (41.8) for DME (p = 0.001), and 76.1 (48.2) for NoDR (p = 0.008). There were no differences in IgG, IgM, or IgA that would be specific for DR or for DME. Type 2 diabetic patients had higher levels of IgA autoantibodies than type 1 diabetic patients (86.0 and 65.5, resp., p = 0.004) and the highest levels in IgA were found in type 2 diabetic patients with PDR (119.1, p > 0.001). Conclusions. IgA autoantibodies were increased in PDR, especially in type 2 diabetes. The high levels of IgA in PDR, and especially in type 2 PDR patients, reflect the inflammatory process and enlighten the role of oxLDL and its autoantibodies in PDR.
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Affiliation(s)
- Satu Vavuli
- PEDEGO Research Unit, Department of Ophthalmology, Medical Research Center (MRC Oulu), Oulu University Hospital and University of Oulu, Oulu, Finland
- Research Unit of Internal Medicine, Medical Research Center Oulu (MRC Oulu), Oulu University Hospital and University of Oulu, Oulu, Finland
- Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Tuire Salonurmi
- Research Unit of Internal Medicine, Medical Research Center Oulu (MRC Oulu), Oulu University Hospital and University of Oulu, Oulu, Finland
- Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Sirpa Loukovaara
- Department of Ophthalmology, Helsinki University Hospital, University of Helsinki, Helsinki, Finland
| | - Antti E. Nissinen
- Research Unit of Internal Medicine, Medical Research Center Oulu (MRC Oulu), Oulu University Hospital and University of Oulu, Oulu, Finland
- Biocenter Oulu, University of Oulu, Oulu, Finland
- Research Unit of Biomedicine, Medical Research Center Oulu (MRC Oulu), Oulu University Hospital and University of Oulu, Oulu, Finland
| | - Markku J. Savolainen
- Research Unit of Internal Medicine, Medical Research Center Oulu (MRC Oulu), Oulu University Hospital and University of Oulu, Oulu, Finland
- Biocenter Oulu, University of Oulu, Oulu, Finland
| | - M. Johanna Liinamaa
- PEDEGO Research Unit, Department of Ophthalmology, Medical Research Center (MRC Oulu), Oulu University Hospital and University of Oulu, Oulu, Finland
- Research Unit of Internal Medicine, Medical Research Center Oulu (MRC Oulu), Oulu University Hospital and University of Oulu, Oulu, Finland
- *M. Johanna Liinamaa:
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Engelbertsen D, Vallejo J, Quách TD, Fredrikson GN, Alm R, Hedblad B, Björkbacka H, Rothstein TL, Nilsson J, Bengtsson E. Low Levels of IgM Antibodies against an Advanced Glycation Endproduct–Modified Apolipoprotein B100 Peptide Predict Cardiovascular Events in Nondiabetic Subjects. THE JOURNAL OF IMMUNOLOGY 2015; 195:3020-5. [DOI: 10.4049/jimmunol.1402869] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 07/24/2015] [Indexed: 12/18/2022]
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Malondialdehyde-modified low-density lipoprotein is a predictor of cardiac events in patients with stable angina on lipid-lowering therapy after percutaneous coronary intervention using drug-eluting stent. Atherosclerosis 2015; 239:311-7. [DOI: 10.1016/j.atherosclerosis.2015.01.026] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 01/19/2015] [Accepted: 01/19/2015] [Indexed: 11/24/2022]
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Rahsepar AA, Mirzaee A, Moodi F, Moohebati M, Tavallaie S, Khorashadizadeh F, Mottahedi B, Esfehanizadeh J, Azari A, Khojasteh R, Mousavi S, Paydar R, Amini M, Ghayour-Mobarhan M, Ferns GA, Sahebkar A. Malondialdehyde-Modified LDL IgG Antibody Levels and Indices of Cardiac Function in Valvular Heart and Coronary Artery Disease Patients. Med Princ Pract 2015; 24:424-31. [PMID: 26139161 PMCID: PMC5588258 DOI: 10.1159/000431178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 05/06/2015] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE To compare the changes in anti-malondialdehyde-modified low-density lipoprotein (MDA-LDL) IgG levels among patients undergoing off-pump and on-pump coronary artery bypass grafting (CABG) or valvuloplasty. SUBJECTS AND METHODS A total of 38, 39 and 34 patients who underwent off-pump CABG, on-pump CABG and valvuloplasty, respectively, were enrolled in this study. Serum anti-MDA-LDL IgG values were measured 24 h before and after the operative procedures and at discharge. Echocardiography was also done before surgery and before discharge. The results were compared with values from 50 healthy controls. RESULTS In all patients, a reduction in antibody titers was observed post-operatively. However, the decrease was significant only in the off-pump CABG - before surgery: 42.33 (25.83-58.51), after surgery: 30.86 (16.36-51.33) and at discharge: 10.96 (6.82-23.57; p = 0.027). There was a significant positive association between anti-MDA-LDL IgG levels and ejection fraction (r = 0.248, p = 0.036) and a negative association with E/E', a marker of pulmonary capillary wedge pressure, in the coronary patients (r = -0.345, p = 0.012), but no significant associations were found in patients with valvular heart disease. CONCLUSIONS Serum anti-MDA-LDL IgG levels were associated with cardiac function indices in coronary patients undergoing CABG.
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Affiliation(s)
- Amir Ali Rahsepar
- Biochemistry of Nutrition Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Asadollah Mirzaee
- Cardiovascular Research Center, School of Medicine, Mashhad, Iran
- Department of Cardiovascular Surgery, Ghaem Hospital, Mashhad, Iran
| | - Fatemeh Moodi
- Cardiovascular Research Center, School of Medicine, Mashhad, Iran
| | - Mohsen Moohebati
- Cardiovascular Research Center, School of Medicine, Mashhad, Iran
| | - Shima Tavallaie
- Biochemistry of Nutrition Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Fatemeh Khorashadizadeh
- Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | | | | | - Ali Azari
- Cardiovascular Research Center, School of Medicine, Mashhad, Iran
| | - Roshanak Khojasteh
- Biochemistry of Nutrition Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Somayeh Mousavi
- Cardiovascular Research Center, School of Medicine, Mashhad, Iran
| | - Roghayeh Paydar
- Cardiovascular Research Center, School of Medicine, Mashhad, Iran
| | - Maral Amini
- Cardiovascular Research Center, School of Medicine, Mashhad, Iran
| | - Majid Ghayour-Mobarhan
- Cardiovascular Research Center, School of Medicine, Mashhad, Iran
- *Majid Ghayour-Mobarhan, Cardiovascular Research Center, School of Medicine, Mashhad University of Medical Science, Mashhad 9177948564 (Iran), E-Mail
| | - Gordon A. Ferns
- Brighton and Sussex Medical School, Division of Medical Education, Falmer, UK
| | - Amirhossein Sahebkar
- Biotechnology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
- Metabolic Research Centre, Royal Perth Hospital, School of Medicine and Pharmacology, University of Western Australia, Perth, W.A., Australia
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Zhu L, He Z, Wu F, Ding R, Jiang Q, Zhang J, Fan M, Wang X, Eva B, Jan N, Liang C, Wu Z. Immunization with advanced glycation end products modified low density lipoprotein inhibits atherosclerosis progression in diabetic apoE and LDLR null mice. Cardiovasc Diabetol 2014; 13:151. [PMID: 25391642 PMCID: PMC4234834 DOI: 10.1186/s12933-014-0151-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 10/22/2014] [Indexed: 01/10/2023] Open
Abstract
Background Diabetes accelerates atherosclerosis through undefined molecular mechanisms. Hyperglycemia induces formation of advanced glycation end product (AGE)-modified low-density lipoprotein (LDL). Anti-AGE-LDL autoantibodies favor atherosclerosis (AS) progression in humans, while anti oxidized LDL immunization inhibits AS in hypercholesterolemic, non-diabetic mice. We here investigated if AGE-LDL immunization protects against AS in diabetic mice. Methods After diabetes induction with streptozotocin and high fat diet, both low density lipoprotein receptor (LDLR)−/− and apoE female mice were randomized to: AGE-LDL immunization with aluminum hydroxide (Alum) adjuvant; Alum alone; or PBS. Results AGE-LDL immunization: significantly reduced AS; induced specific plasma IgM and IgG antibodies; upregulated splenic Th2, Treg and IL-10 levels, without altering Th1 or Th17 cells; and increased serum high density lipoprotein(HDL) while numerically lowering HbA1c levels. Conclusions Subcutaneous immunization with AGE-LDL significantly inhibits atherosclerosis progression in hyperlipidemic diabetic mice possibly through activation of specific humoral and cell mediated immune responses and metabolic control improvement. Electronic supplementary material The online version of this article (doi:10.1186/s12933-014-0151-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lin Zhu
- Department of Cardiology, Shanghai Changzheng Hospital, Second Military Medical University, No. 415 Fengyang Road, Shanghai, 200003, People's Republic of China. .,457th hospital of PLA, Wuhan, People's Republic of China.
| | - Zhiqing He
- Department of Cardiology, Shanghai Changzheng Hospital, Second Military Medical University, No. 415 Fengyang Road, Shanghai, 200003, People's Republic of China.
| | - Feng Wu
- Department of Cardiology, Shanghai Changzheng Hospital, Second Military Medical University, No. 415 Fengyang Road, Shanghai, 200003, People's Republic of China. .,Department of Research, Center for Stem Cell Biology, Roger Williams Medical Center, Boston University School of Medicine, Providence, RI, USA.
| | - Ru Ding
- Department of Cardiology, Shanghai Changzheng Hospital, Second Military Medical University, No. 415 Fengyang Road, Shanghai, 200003, People's Republic of China.
| | - Qixia Jiang
- Department of Cardiology, Shanghai Changzheng Hospital, Second Military Medical University, No. 415 Fengyang Road, Shanghai, 200003, People's Republic of China.
| | - Jiayou Zhang
- Department of Cardiology, Shanghai Changzheng Hospital, Second Military Medical University, No. 415 Fengyang Road, Shanghai, 200003, People's Republic of China.
| | - Min Fan
- Department of Cardiology, Shanghai Changzheng Hospital, Second Military Medical University, No. 415 Fengyang Road, Shanghai, 200003, People's Republic of China.
| | - Xing Wang
- Department of Cardiology, Shanghai Changzheng Hospital, Second Military Medical University, No. 415 Fengyang Road, Shanghai, 200003, People's Republic of China.
| | - Bengtsson Eva
- Experimental Cardiovascular Research, CRC 91:12, Lund University, Entrance 72, Skåne University Hospital Malmö, SE-205 02, Malmö, Sweden.
| | - Nilsson Jan
- Experimental Cardiovascular Research, CRC 91:12, Lund University, Entrance 72, Skåne University Hospital Malmö, SE-205 02, Malmö, Sweden.
| | - Chun Liang
- Department of Cardiology, Shanghai Changzheng Hospital, Second Military Medical University, No. 415 Fengyang Road, Shanghai, 200003, People's Republic of China.
| | - Zonggui Wu
- Department of Cardiology, Shanghai Changzheng Hospital, Second Military Medical University, No. 415 Fengyang Road, Shanghai, 200003, People's Republic of China.
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Pugliese G, Iacobini C, Pesce CM, Menini S. Galectin-3: an emerging all-out player in metabolic disorders and their complications. Glycobiology 2014; 25:136-50. [PMID: 25303959 DOI: 10.1093/glycob/cwu111] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Galectin-3 has been increasingly recognized as an important modulator of several biological functions, by interacting with several molecules inside and outside the cell, and an emerging player in numerous disease conditions. Galectin-3 exerts various and sometimes contrasting effects according to its location, type of injury or site of damage. Strong evidence indicates that galectin-3 participates in the pathogenesis of diabetic complications via its receptor function for advanced glycation end-products (AGEs) and advanced lipoxidation end-products (ALEs). AGEs/ALEs are produced to an increased extent in target organs of complications, such as kidney and vessels; here, lack of galectin-3 impairs their removal, leading to accelerated damage. In contrast, in the liver, AGE/ALE tissue content and injury are decreased, because lack of galectin-3 results in reduced uptake and tissue accumulation of these by-products. Some of these effects can be explained by changes in the expression of receptor for AGEs (RAGE), associated with galectin-3 deletion and consequent changes in AGE/ALE tissue levels. Furthermore, galectin-3 might exert AGE/ALE- and RAGE-independent effects, favoring resolution of inflammation and modulating fibrogenesis and ectopic osteogenesis. These effects are mediated by intracellular and extracellular galectin-3, the latter via interaction with N-glycans at the cell surface to form lattice structures. Recently, galectin-3 has been implicated in the development of metabolic disorders because it favors glucose homeostasis and prevents the deleterious activation of adaptive and innate immune response to obesogenic/diabetogenic stimuli. In conclusion, galectin-3 is an emerging all-out player in metabolic disorders and their complications that deserves further investigation as the potential target of therapeutic intervention.
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Affiliation(s)
- Giuseppe Pugliese
- Department of Clinical and Molecular Medicine, "La Sapienza" University, Via di Grottarossa, 1035-1039, Rome 00189, Italy
| | - Carla Iacobini
- Department of Clinical and Molecular Medicine, "La Sapienza" University, Via di Grottarossa, 1035-1039, Rome 00189, Italy
| | - Carlo M Pesce
- DINOGMI, University of Genoa Medical School, Genoa 16132, Italy
| | - Stefano Menini
- Department of Clinical and Molecular Medicine, "La Sapienza" University, Via di Grottarossa, 1035-1039, Rome 00189, Italy
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Bhat S, Mary S, Banarjee R, Giri AP, Kulkarni MJ. Immune response to chemically modified proteome. Proteomics Clin Appl 2014; 8:19-34. [PMID: 24375944 DOI: 10.1002/prca.201300068] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 12/06/2013] [Accepted: 12/09/2013] [Indexed: 11/10/2022]
Abstract
Both enzymatic and nonenzymatic PTMs of proteins involve chemical modifications. Some of these modifications are prerequisite for the normal functioning of cell, while other chemical modifications render the proteins as "neo-self" antigens, which are recognized as "non-self" leading to aberrant cellular and humoral immune responses. However, these modifications could be a secondary effect of autoimmune diseases, as in the case of type I diabetes, hyperglycemia leads to protein glycation. The enigma of chemical modifications and immune response is akin to the "chick-and-egg" paradox. Nevertheless, chemical modifications regulate immune response. In some of the well-known autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, and multiple sclerosis, chemically modified proteins act as autoantigens forming immune complexes. In some instances, chemical modifications are also involved in regulating immune response during pathogen infection. Further, the usefulness of proteomic analysis of immune complexes is briefly discussed.
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Affiliation(s)
- Shweta Bhat
- Proteomics Facility, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Pune, India
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21
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Orekhov AN, Bobryshev YV, Sobenin IA, Melnichenko AA, Chistiakov DA. Modified low density lipoprotein and lipoprotein-containing circulating immune complexes as diagnostic and prognostic biomarkers of atherosclerosis and type 1 diabetes macrovascular disease. Int J Mol Sci 2014; 15:12807-41. [PMID: 25050779 PMCID: PMC4139876 DOI: 10.3390/ijms150712807] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Revised: 06/29/2014] [Accepted: 07/03/2014] [Indexed: 12/14/2022] Open
Abstract
In atherosclerosis; blood low-density lipoproteins (LDL) are subjected to multiple enzymatic and non-enzymatic modifications that increase their atherogenicity and induce immunogenicity. Modified LDL are capable of inducing vascular inflammation through activation of innate immunity; thus, contributing to the progression of atherogenesis. The immunogenicity of modified LDL results in induction of self-antibodies specific to a certain type of modified LDL. The antibodies react with modified LDL forming circulating immune complexes. Circulating immune complexes exhibit prominent immunomodulatory properties that influence atherosclerotic inflammation. Compared to freely circulating modified LDL; modified LDL associated with the immune complexes have a more robust atherogenic and proinflammatory potential. Various lipid components of the immune complexes may serve not only as diagnostic but also as essential predictive markers of cardiovascular events in atherosclerosis. Accumulating evidence indicates that LDL-containing immune complexes can also serve as biomarker for macrovascular disease in type 1 diabetes.
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Affiliation(s)
- Alexander N Orekhov
- Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, Russian Academy of Medical Sciences, Moscow 125315, Russia.
| | - Yuri V Bobryshev
- Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, Russian Academy of Medical Sciences, Moscow 125315, Russia.
| | - Igor A Sobenin
- Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, Russian Academy of Medical Sciences, Moscow 125315, Russia.
| | - Alexandra A Melnichenko
- Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, Russian Academy of Medical Sciences, Moscow 125315, Russia.
| | - Dimitry A Chistiakov
- Department of Medical Nanobiotechnology, Pirogov Russian State Medical University, Moscow 117997, Russia.
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Ma L, Wu J, Niu D, Yu R, Song J, Zhang C, Wang J. Serum lipoprotein(a) complexes with beta2-glycoprotein I levels in patients with ischemic stroke. Clin Chim Acta 2014; 429:163-7. [DOI: 10.1016/j.cca.2013.11.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 11/19/2013] [Accepted: 11/25/2013] [Indexed: 11/30/2022]
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Oxidized LDL and AGE-LDL in circulating immune complexes strongly predict progression of carotid artery IMT in type 1 diabetes. Atherosclerosis 2013; 231:315-22. [PMID: 24267245 DOI: 10.1016/j.atherosclerosis.2013.09.027] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 09/05/2013] [Accepted: 09/27/2013] [Indexed: 11/24/2022]
Abstract
OBJECTIVE Over 90% of modified LDL in circulation is associated to specific antibodies circulating as part of immune complexes (IC); however, few studies have examined their relationship with cardiovascular disease. METHODS We report the relationship between circulating concentrations of IC of oxidized LDL (oxLDL-IC), malondialdehyde-LDL (MDA-LDL-IC) and advanced glycation end products-LDL (AGE-LDL-IC) and progression of atherosclerosis over a 12 year period in 467 individuals with type 1 diabetes who participated in the Diabetes Control and Complications Trial (DCCT) and the Epidemiology of Diabetes Interventions and Complications (EDIC) study. OxLDL-IC, AGE-LDL-IC and MDA-LDL-IC levels were measured at DCCT closeout. Internal carotid intima-medial thickness (IMT) was measured at EDIC follow-up years 1, 6 and 12. RESULTS OxLDL-IC, AGE-LDL-IC and MDA-LDL-IC levels were significantly correlated with age, lipid levels, blood pressure levels and albumin excretion rates. Levels of oxLDL, AGE-LDL and MDA-LDL in isolated LDL-IC were highly inter-correlated (r = 0.66-0.84, P < 0.0001). After adjusting for cardiovascular risk factors individuals in the upper quartile of oxLDL-IC had a 2.98-fold increased odds (CI: 1.34, 6.62) of having IMT ≥ 1.00 mm and had a 5.13-fold increased odds (CI: 1.98, 13.3) of having significant IMT progression, relative to those in the lowest quartile. Parallel odds ratios for AGE-LDL-IC were 2.95 (CI: 1.37, 6.34) and 3.50 (CI: 1.38, 8.86), while results for MDA-LDL-IC were 1.76 (0.87, 3.56) and 2.86 (1.20, 6.81). CONCLUSION Our study indicates that high levels of oxLDL-IC and AGE-LDL-IC are important predictors of carotid intima-medial thickening in patients with type 1 diabetes.
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Menini S, Iacobini C, Ricci C, Blasetti Fantauzzi C, Salvi L, Pesce CM, Relucenti M, Familiari G, Taurino M, Pugliese G. The galectin-3/RAGE dyad modulates vascular osteogenesis in atherosclerosis. Cardiovasc Res 2013; 100:472-80. [DOI: 10.1093/cvr/cvt206] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Lopes-Virella MF, Virella G. Pathogenic role of modified LDL antibodies and immune complexes in atherosclerosis. J Atheroscler Thromb 2013; 20:743-54. [PMID: 23965492 DOI: 10.5551/jat.19281] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
There is strong evidence supporting a key role of the adaptive immune response in atherosclerosis, given that both activated Th cells producing predominantly interferon-γ and oxidized LDL (oxLDL) and the corresponding antibodies have been isolated from atheromatous plaques. Studies carried out using immune complexes (IC) prepared with human LDL and rabbit antibodies have demonstrated proatherogenic and pro-inflammatory properties, mostly dependent on the engagement of Fcγ receptors Ⅰ and Ⅱ in macrophages and macrophage-like cell lines. Following the development of a methodology for isolating modified LDL (mLDL) antibodies from serum and isolated IC, it was confirmed that antibodies reacting with oxLDL and advanced glycation end product-modified LDL are predominantly IgG of subtypes 1 and 3 and that mLDL IC prepared with human reagents possesses pro-inflammatory and proatherogenic properties. In previous studies, LDL separated from isolated IC has been analyzed for its modifications, and the reactivity of antibodies isolated from the same IC with different LDL modifications has been tested. Recently, we obtained strong evidence suggesting that the effects of mLDL IC on phagocytic cells are modulated by the composition of the mLDL. Clinical studies have shown that the level of mLDL in circulating IC is a strong predictor of cardiovascular disease (CVD) and, in diabetic patients, other significant complications, such as nephropathy and retinopathy. In conclusion, there is convincing ex vivo and clinical data supporting the hypothesis that, in humans, the humoral immune response to mLDL is pathogenic rather than protective.
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Virella G, Colglazier J, Chassereau C, Hunt KJ, Baker NL, Lopes-Virella MF. Immunoassay of modified forms of human low density lipoprotein in isolated circulating immune complexes. J Immunoassay Immunochem 2013; 34:61-74. [PMID: 23323982 DOI: 10.1080/15321819.2012.683500] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Modified lipoproteins are able to induce inflammatory reactions through innate immunity pathways and are immunogenic, leading to an autoimmune response that results in the formation of proinflammatory immune complexes. The measurement of circulating oxidized lipoproteins and corresponding antibodies has, therefore, been proposed as an approach to assess the risk for complications in patients with diabetes and for the risk of cardiovascular disease in the general population. However, the majority of modified low density lipoprotein (LDL) in the peripheral circulation exists in the form of immune complexes, and this is a significant obstacle for the measurement of modified LDL and the corresponding antibodies. In this manuscript, we describe in detail the methodology developed by our group for isolation and fractionation of circulating immune complexes (IC), allowing the accurate assay of different LDL modifications. This approach has resulted in several studies showing that the levels of modified LDL are risk factors with a stronger association to diabetic retinopathy, nephropathy, and macrovascular disease. Ongoing research is focused on evaluating the predictive power of modified LDL levels for the development or progression of atherosclerotic cardiovascular disease in other patient populations and on the simplification of the assay to make it more applicable to diagnostic laboratories.
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Affiliation(s)
- Gabriel Virella
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC 29425, USA.
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27
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Lopes-Virella MF, Virella G. The role of immunity and inflammation in the development of diabetic complications. Diabetol Int 2013. [DOI: 10.1007/s13340-013-0105-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Does oxidized LDL contribute to atherosclerotic plaque formation and microvascular complications in patients with type 1 diabetes? Clin Biochem 2012; 45:1620-3. [DOI: 10.1016/j.clinbiochem.2012.08.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 08/20/2012] [Accepted: 08/21/2012] [Indexed: 11/21/2022]
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Lopes-Virella MF, Hunt KJ, Baker NL, Virella G, Moritz T. The levels of MDA-LDL in circulating immune complexes predict myocardial infarction in the VADT study. Atherosclerosis 2012; 224:526-31. [PMID: 22963984 PMCID: PMC4240617 DOI: 10.1016/j.atherosclerosis.2012.08.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 07/25/2012] [Accepted: 08/09/2012] [Indexed: 01/13/2023]
Abstract
OBJECTIVE Circulating immune complexes (IC) containing modified forms of LDL (mLDL) are strongly pro-inflammatory and strong predictors of cardiovascular disease (CVD) progression in type 1 diabetes. The present study was undertaken to determine whether the levels of oxidized LDL (oxLDL), malondialdehyde-LDL (MDA-LDL) and advanced glycation end products-LDL (AGE-LDL) in IC predict incident CVD events in type 2 diabetes (VADT cohort). METHODS AND RESULTS Levels of mLDL in IC were measured in 907 patients of the VADT cohort, a median of two years after entry into the study. Participants were followed for an average of 3.7 years for vascular outcomes. Hazard ratios (HRs) for CV endpoints in relation to mLDL-IC quartiles were calculated by Cox proportional hazard models. The primary composite CVD endpoint included documented myocardial infarction (MI); stroke; death from CVD; congestive heart failure; cardiac, cerebrovascular, or peripheral VD surgical intervention; inoperable CVD; and amputation for ischemic gangrene. During follow-up, 4.7% and 16.8% of participants had an MI or a composite endpoint, respectively. After adjustments by conventional risk factors, individuals in the highest quartile of MDA-LDL-IC were at higher risk of MI [HR = 2.44 (95% CI: 1.03, 5.77)] and composite endpoint [HR = 1.71 (95% CI: 1.04, 2.80)], relative to individuals in the lowest quartile. Similar comparisons for oxLDL and AGE-LDL levels yielded HR values of 1.08 and 1.31 for MI and 0.91 and 1.34 for composite endpoint. CONCLUSIONS Our study indicates that high levels of MDA-LDL in isolated IC predict future MI and acute CV events in patients with type 2 diabetes.
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Affiliation(s)
- Maria F Lopes-Virella
- Department of Medicine, Medical University of South Carolina, Charleston, SC, United States.
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Truman JP, Al Gadban MM, Smith KJ, Jenkins RW, Mayroo N, Virella G, Lopes-Virella MF, Bielawska A, Hannun YA, Hammad SM. Differential regulation of acid sphingomyelinase in macrophages stimulated with oxidized low-density lipoprotein (LDL) and oxidized LDL immune complexes: role in phagocytosis and cytokine release. Immunology 2012; 136:30-45. [PMID: 22236141 DOI: 10.1111/j.1365-2567.2012.03552.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Oxidized low-density lipoprotein (oxLDL) and oxLDL-containing immune complexes (oxLDL-IC) contribute to the formation of lipid-laden macrophages (foam cells). Fcγ receptors mediate uptake of oxLDL-IC, whereas scavenger receptors internalize oxLDL. We have previously reported that oxLDL-IC, but not free oxLDL, activate macrophages and prolong their survival. Sphingomyelin is a major constituent of cell membranes and lipoprotein particles and acid sphingomyelinase (ASMase) hydrolyses sphingomyelin to generate the bioactive lipid ceramide. ASMase exists in two forms: lysosomal (L-ASMase) and secretory (S-ASMase). In this study we examined whether oxLDL and oxLDL-IC regulate ASMase differently, and whether ASMase mediates monocyte/macrophage activation and cytokine release. The oxLDL-IC, but not oxLDL, induced early and consistent release of catalytically active S-ASMase. The oxLDL-IC also consistently stimulated L-ASMase activity, whereas oxLDL induced a rapid transient increase in L-ASMase activity before it steadily declined below baseline. Prolonged exposure to oxLDL increased L-ASMase activity; however, activity remained significantly lower than that induced by oxLDL-IC. Further studies were aimed at defining the function of the activated ASMase. In response to oxLDL-IC, heat-shock protein 70B' (HSP70B') was up-regulated and localized with redistributed ASMase in the endosomal compartment outside the lysosome. Treatment with oxLDL-IC induced the formation and release of HSP70-containing and IL-1β-containing exosomes via an ASMase-dependent mechanism. Taken together, the results suggest that oxLDL and oxLDL-IC differentially regulate ASMase activity, and the pro-inflammatory responses to oxLDL-IC are mediated by prolonged activation of ASMase. These findings may contribute to increased understanding of mechanisms mediating macrophage involvement in atherosclerosis.
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Affiliation(s)
- Jean-Philip Truman
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC 29425, USA
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Rahsepar AA, Mirzaee A, Moodi F, Moohebati M, Tavallaie S, Eshraghi A, Alavi MS, Khorashadizadeh F, Pourghadamyari H, Paydar R, Amini M, Khojasteh R, Mousavi S, Sahebi M, Ghayour-Mobarhan M, Ferns GA. Prooxidant-Antioxidant Balance and Antioxidized LDL Antibody Level Values and Cardiac Function in Patients with Coronary Artery Disease. Cardiology 2012; 122:203-9. [DOI: 10.1159/000339273] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2012] [Accepted: 04/27/2012] [Indexed: 11/19/2022]
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Virella G, Lopes-Virella MF. The Pathogenic Role of the Adaptive Immune Response to Modified LDL in Diabetes. Front Endocrinol (Lausanne) 2012; 3:76. [PMID: 22715334 PMCID: PMC3375400 DOI: 10.3389/fendo.2012.00076] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Accepted: 05/28/2012] [Indexed: 01/12/2023] Open
Abstract
The main causes of morbidity and mortality in diabetes are macro and microvascular complications, including atherosclerosis, nephropathy, and retinopathy. As the definition of atherosclerosis as a chronic inflammatory disease became widely accepted, it became important to define the triggers of vascular inflammation. Oxidative and other modifications of lipids and lipoproteins emerged as major pathogenic factors in atherosclerosis. Modified forms of LDL (mLDL) are pro-inflammatory by themselves, but, in addition, mLDLs including oxidized, malondialdehyde (MDA)-modified, and advanced glycation end (AGE)-product-modified LDL induce autoimmune responses in humans. The autoimmune response involves T cells in the arterial wall and synthesis of IgG antibodies. The IgG auto-antibodies that react with mLDLs generate immune complexes (IC) both intra and extravascularly, and those IC activate the complement system as well as phagocytic cells via the ligation of Fcγ receptors. In vitro studies proved that the pro-inflammatory activity of IC containing mLDL (mLDL-IC) is several-fold higher than that of the modified LDL molecules. Clinical studies support the pathogenic role of mLDL-IC in the development of macrovascular disease patients with diabetes. In type 1 diabetes, high levels of oxidized and AGE-LDL in IC were associated with internal carotid intima-media thickening and coronary calcification. In type 2 diabetes, high levels of MDA-LDL in IC predicted the occurrence of myocardial infarction. There is also evidence that mLDL-IC are involved in the pathogenesis of diabetic nephropathy and retinopathy. The pathogenic role of mLDL-IC is not unique to diabetic patients, because those IC are also detected in non-diabetic individuals. But mLDL-IC are likely to reach higher concentrations and have a more prominent pathogenic role in diabetes due to increased antigenic load secondary to high oxidative stress and to enhanced autoimmune responses in type 1 diabetes.
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Affiliation(s)
- Gabriel Virella
- Department of Microbiology and Immunology, Medical University of South CarolinaCharleston, SC, USA
- *Correspondence: Gabriel Virella, Department of Microbiology and Immunology, Medical University of South Carolina, 173 Ashley Avenue, MSC 504, Charleston, SC 29425-5040, USA. e-mail:
| | - Maria F. Lopes-Virella
- Department of Microbiology and Immunology, Medical University of South CarolinaCharleston, SC, USA
- Ralph E. Johnson VA Medical CenterCharleston, SC, USA
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Zhang C, Li X, Niu D, Zi R, Wang C, Han A, Wang X, Li K, Wang J. Increased serum levels of β₂-GPI-Lp(a) complexes and their association with premature atherosclerosis in patients with rheumatoid arthritis. Clin Chim Acta 2011; 412:1332-6. [PMID: 21473861 DOI: 10.1016/j.cca.2011.03.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2010] [Revised: 03/26/2011] [Accepted: 03/28/2011] [Indexed: 11/17/2022]
Abstract
BACKGROUND Our recent study found the existence of complexes of β₂-glycoprotein I (β₂-GPI) with lipoprotein(a)[Lp(a)] in circulation and the complex concentrations were increased in sera of systemic lupus erythematosus patients. The concentration of β₂-GPI-Lp(a) and its relationship with premature atherosclerosis were evaluated in rheumatoid arthritis (RA) patients. METHODS Serum concentrations of β₂-GPI-Lp(a) were measured in 53 active RA patients and 40 healthy controls by a "sandwich" ELISA. β₂-GPI-ox-LDL, ox-Lp(a), ox-LDL and anti-β₂-GPI were also measured by ELISAs. In addition, inflammatory markers were examined. RESULTS Serum β₂-GPI-Lp(a) (1.12±0.25 U/ml vs. 0.87±0.19 U/ml, P<0.0001) and β₂-GPI-ox-LDL (1.01±0.20 U/ml vs. 0.80±0.08 U/ml, P<0.0001) concentrations in RA were both significantly higher than those of controls. Ox-Lp(a) (8.38±6.69 mg/l vs. 5.49±4.31 mg/l, P<0.05) and ox-LDL (0.68±0.65 mg/l vs. 0.37±0.13 mg/l, P=0.001) were also higher in RA than in controls. The area under the ROC curve (AUC) for β₂-GPI-Lp(a) (0.787) was larger than for ox-Lp(a) (0.731). AUC of β₂-GPI-ox-LDL (0.858) was also larger than for ox-LDL (0.785). β₂-GPI-Lp(a) and β₂-GPI-ox-LDL were positively correlated with ox-Lp(a), ox-LDL and CRP, respectively. CONCLUSIONS β₂-GPI-Lp(a) complex concentrations increased in active RA. Inflammation and oxidative stress in RA contribute to the increase of ox-Lp(a) and subsequently the formation of β₂-GPI-Lp(a).
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Affiliation(s)
- Chunni Zhang
- Department of Biochemistry, Jinling Hospital, Clinical School of Medical College, Nanjing University, 210002 Nanjing, PR China
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Lopes-Virella MF, Hunt KJ, Baker NL, Lachin J, Nathan DM, Virella G. Levels of oxidized LDL and advanced glycation end products-modified LDL in circulating immune complexes are strongly associated with increased levels of carotid intima-media thickness and its progression in type 1 diabetes. Diabetes 2011; 60:582-9. [PMID: 20980456 PMCID: PMC3028359 DOI: 10.2337/db10-0915] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
OBJECTIVE High cholesterol levels in circulating immune complexes (IC), surrogate markers of modified LDL, are associated with increased carotid intima-media thickness (IMT) and cardiovascular events in type 1 diabetes. Different modifications of LDL are involved in IC formation, but which of these are predictive of vascular events is not known. Therefore, we measured oxidized LDL (oxLDL), advanced glycation end products-modified LDL (AGE-LDL), and malondialdehyde-modified LDL (MDA-LDL) in IC and determined their relationship with increased carotid IMT and compared the strength of the association with that observed with conventional risk factors. RESEARCH DESIGN AND METHODS Levels of oxLDL, AGE-LDL, and MDA-LDL were measured in circulating IC isolated from sera of 479 patients of the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) cohort, collected at baseline. Internal and common carotid IMT were measured 8 and 14 years later by DCCT/EDIC. RESULTS OxLDL, AGE-LDL, and MDA-LDL levels in circulating IC were significantly correlated with diabetes duration, BMI, and lipid and blood pressure, but not with age. Multivariate logistic regression models indicated that individuals in the highest versus lowest quartile of oxLDL and AGE-LDL in IC had a 6.11-fold [confidence interval (CI) 2.51-14.8] and a 6.4-fold (CI 2.53-16.2) increase in the odds of having high carotid IMT, respectively, after adjusting for conventional risk factors. Parallel analyses resulted in odds ratios of 2.62 (CI 1.24, 5.55) for LDL-C, 1.45 (CI 0.69, 3.03) for diastolic blood pressure, and 2.33 (CI 1.09, 4.99) for A1C. CONCLUSIONS OxLDL and AGE-LDL in circulating IC were significantly associated with progression and increased levels of carotid IMT in type 1 diabetes.
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Affiliation(s)
- Maria F Lopes-Virella
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, USA.
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Lopes-Virella MF, Baker NL, Hunt KJ, Lachin J, Nathan D, Virella G. Oxidized LDL immune complexes and coronary artery calcification in type 1 diabetes. Atherosclerosis 2010; 214:462-7. [PMID: 21156319 DOI: 10.1016/j.atherosclerosis.2010.11.012] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Revised: 10/20/2010] [Accepted: 11/01/2010] [Indexed: 01/16/2023]
Abstract
OBJECTIVE Oxidized LDL (oxLDL) and oxLDL antibodies form immune complexes (IC) that reflect essential components in the development of atherosclerosis: dyslipidemia, oxidative stress and induction of a pro-inflammatory humoral immune response. We measured oxLDL in IC (oxLDL-IC) isolated from patients with type 1 diabetes to assess the relationship between oxLDL-IC and coronary artery calcification (CAC). METHODS OxLDL was measured in IC isolated from baseline samples from a subgroup of 476 patients of the Diabetes Control and Complications Trial (DCCT). CAC was determined by computed tomography (CT) 11-20 years later. Multivariable log-binomial regression models were used to estimate the risk ratios associated with having a high CAC score with an increase of 1 standard deviation (SD) of the natural logarithm of oxLDL-IC. RESULTS Multivariable regression models indicate that a 1 SD increase in the levels of oxLDL-IC was associated with a 37% increase in the risk of having high CAC score (RR=1.36; 95% CI: 1.12-1.67) at follow-up after adjustment for DCCT treatment group, retinopathy/AER groups, gender and CT scanning site as well as baseline age, diabetes duration and HbA1C %. Further adjustment for smoking status, blood pressure and LDL resulted in a risk ratio of 1.23 (95% CI: 1.01-1.50) which remained statistically significant indicating that baseline oxLDL-IC is independently associated with the development of CAC. DISCUSSION Increased levels of oxLDL-IC are associated with the development of coronary calcification. This observation reinforces previously published clinical and experimental data demonstrating that oxLD-IC has pro-inflammatory and proatherogenic properties.
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Affiliation(s)
- Maria F Lopes-Virella
- Department of Medicine, Medical University of South Carolina, Charleston, SC, United States.
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Faulin TDES, Cavalcante MF, Abdalla DSP. Role of electronegative LDL and its associated antibodies in the pathogenesis of atherosclerosis. ACTA ACUST UNITED AC 2010. [DOI: 10.2217/clp.10.52] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Al Gadban MM, Smith KJ, Soodavar F, Piansay C, Chassereau C, Twal WO, Klein RL, Virella G, Lopes-Virella MF, Hammad SM. Differential trafficking of oxidized LDL and oxidized LDL immune complexes in macrophages: impact on oxidative stress. PLoS One 2010; 5. [PMID: 20824093 PMCID: PMC2932722 DOI: 10.1371/journal.pone.0012534] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Accepted: 08/11/2010] [Indexed: 02/08/2023] Open
Abstract
Background Oxidized low-density lipoproteins (oxLDL) and oxLDL-containing immune complexes (oxLDL-IC) contribute to formation of lipid-laden macrophages (foam cells). It has been shown that oxLDL-IC are considerably more efficient than oxLDL in induction of foam cell formation, inflammatory cytokines secretion, and cell survival promotion. Whereas oxLDL is taken up by several scavenger receptors, oxLDL-IC are predominantly internalized through the FCγ receptor I (FCγ RI). This study examined differences in intracellular trafficking of lipid and apolipoprotein moieties of oxLDL and oxLDL-IC and the impact on oxidative stress. Methodology/Findings Fluorescently labeled lipid and protein moieties of oxLDL co-localized within endosomal and lysosomal compartments in U937 human monocytic cells. In contrast, the lipid moiety of oxLDL-IC was detected in the endosomal compartment, whereas its apolipoprotein moiety advanced to the lysosomal compartment. Cells treated with oxLDL-IC prior to oxLDL demonstrated co-localization of internalized lipid moieties from both oxLDL and oxLDL-IC in the endosomal compartment. This sequential treatment likely inhibited oxLDL lipid moieties from trafficking to the lysosomal compartment. In RAW 264.7 macrophages, oxLDL-IC but not oxLDL induced GFP-tagged heat shock protein 70 (HSP70) and HSP70B', which co-localized with the lipid moiety of oxLDL-IC in the endosomal compartment. This suggests that HSP70 family members might prevent the degradation of the internalized lipid moiety of oxLDL-IC by delaying its advancement to the lysosome. The data also showed that mitochondrial membrane potential was decreased and generation of reactive oxygen and nitrogen species was increased in U937 cell treated with oxLDL compared to oxLDL-IC. Conclusions/Significance Findings suggest that lipid and apolipoprotein moieties of oxLDL-IC traffic to separate cellular compartments, and that HSP70/70B' might sequester the lipid moiety of oxLDL-IC in the endosomal compartment. This mechanism could ultimately influence macrophage function and survival. Furthermore, oxLDL-IC might regulate the intracellular trafficking of free oxLDL possibly through the induction of HSP70/70B'.
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Affiliation(s)
- Mohammed M. Al Gadban
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Kent J. Smith
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Farzan Soodavar
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Christabelle Piansay
- Summer Undergraduate Research Program, College of Graduate Studies, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Charlyne Chassereau
- Division of Endocrinology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Waleed O. Twal
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Richard L. Klein
- Division of Endocrinology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, United States of America
- Research Service, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina, United States of America
| | - Gabriel Virella
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Maria F. Lopes-Virella
- Division of Endocrinology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, United States of America
- Research Service, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina, United States of America
| | - Samar M. Hammad
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
- * E-mail:
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Smith KJ, Twal WO, Soodavar F, Virella G, Lopes-Virella MF, Hammad SM. Heat shock protein 70B' (HSP70B') expression and release in response to human oxidized low density lipoprotein immune complexes in macrophages. J Biol Chem 2010; 285:15985-93. [PMID: 20348092 DOI: 10.1074/jbc.m110.113605] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Heat shock proteins (HSPs) have been implicated in the activation and survival of macrophages. This study examined the role of HSP70B', a poorly characterized member of the HSP70 family, in response to oxidatively modified LDL (oxLDL) and immune complexes prepared with human oxLDL and purified human antibodies to oxLDL (oxLDL-IC) in monocytic and macrophage cell lines. Immunoblot analysis of cell lysates and conditioned medium from U937 cells treated with oxLDL alone revealed an increase in intracellular HSP70B' protein levels accompanied by a concomitant increase in HSP70B' extracellular levels. Fluorescence immunohistochemistry and confocal microscopy, however, demonstrated that oxLDL-IC stimulated the release of HSP70B', which co-localized with cell-associated oxLDL-IC. In HSP70B'-green fluorescent protein-transfected mouse RAW 264.7 cells, oxLDL-IC-induced HSP70B' co-localized with membrane-associated oxLDL-IC as well as the lipid moiety of internalized oxLDL-IC. Furthermore, the data demonstrated that HSP70B' is involved in cell survival, and this effect could be mediated by sphingosine kinase 1 (SK1) activation. An examination of regularly implicated cytokines revealed a significant relationship between HSP70B' and the release of the anti-inflammatory cytokine interleukin-10 (IL-10). Small interfering RNA knockdown of HSP70B' resulted in a corresponding decrease in SK1 mRNA levels and SK1 phosphorylation as well as increased release of IL-10. In conclusion, these findings suggest that oxLDL-IC induce the synthesis and release of HSP70B', and once stimulated, HSP70B' binds to the cell-associated and internalized lipid moiety of oxLDL-IC. The data also implicate HSP70B' in key cellular functions, such as regulation of SK1 activity and release of IL-10, which influence macrophage activation and survival.
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Affiliation(s)
- Kent J Smith
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
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Zhang C, Li K, Shi B, Wang X, Liu X, Qin W, Han A, Wang J. Detection of serum β2-GPI–Lp(a) complexes in patients with systemic lupus erythematosus. Clin Chim Acta 2010; 411:395-9. [DOI: 10.1016/j.cca.2009.12.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Revised: 12/03/2009] [Accepted: 12/09/2009] [Indexed: 11/29/2022]
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Lopes-Virella MF, Virella G. Clinical significance of the humoral immune response to modified LDL. Clin Immunol 2009; 134:55-65. [PMID: 19427818 DOI: 10.1016/j.clim.2009.04.001] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Accepted: 04/03/2009] [Indexed: 12/31/2022]
Abstract
Human low density lipoprotein (LDL) undergoes oxidation and glycation in vivo. By themselves, oxidized LDL (oxLDL) and AGE-LDL have proinflammatory properties and are considered atherogenic. But the atherogenicity of these lipoproteins are significantly increased as a consequence of the formation of immune complexes (IC) involving specific autoantibodies. OxLDL and AGE antibodies have been shown to be predominantly of the IgG1 and IgG3 isotypes. OxLDL antibodies are able to activate the complement system by the classical pathway and to induce FcR-mediated phagocytosis. In vitro and ex vivo studies performed with modified LDL-IC have proven their pro-inflammatory and atherogenic properties. Clinical studies have demonstrated that the levels of circulating modified LDL-IC correlate with parameters indicative of cardiovascular and renal disease in diabetic patients and other patient populations. The possibility that spontaneously formed or induced modified LDL antibodies (particularly IgM oxLDL antibodies) may have a protective effect has been suggested, but the data is unclear and needs to be further investigated.
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Virella G, Carter RE, Saad A, Crosswell EG, Game BA, Lopes-Virella MF. Distribution of IgM and IgG antibodies to oxidized LDL in immune complexes isolated from patients with type 1 diabetes and its relationship with nephropathy. Clin Immunol 2008; 127:394-400. [PMID: 18533284 DOI: 10.1016/j.clim.2008.02.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Modified lipoproteins are immunogenic and play a key pathogenic role in vascular disease. Antibodies to oxidized LDL (oxLDL) are mostly of the pro-inflammatory IgG1 and IgG3 isotypes. We measured IgG and IgM oxLDL antibodies in immune complexes (IC) isolated from 36 patients with type 1 diabetes using a nested case control design. IgG antibodies predominated over IgM antibodies by an 8:1 ratio. IgG antibody concentrations were higher in the nephropathy cases compared to controls (p = 0.09), but no significant difference was observed because of two patients included in the study who had end-stage renal disease (creatinine > 5 mg/dL and glomerular filtration rate (GFR) less than 17 mL/min). After eliminating these patients from the analysis, significant positive associations of IgG antibody concentration with serum creatinine and albumin excretion rate were observed. Similarly, a negative correlation with estimated glomerular filtration rate was observed in this subsample of 34 patients. Differences in IgM antibody concentrations by nephropathy classification were not supported by the data. In conclusion, the predominance of pro-inflammatory IgG oxLDL antibodies is associated with existence of diabetic nephropathy, and a protective role of IgM antibodies could not be demonstrated.
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Affiliation(s)
- Gabriel Virella
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC 29425, USA.
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Hammad SM, Twal WO, Barth JL, Smith KJ, Saad AF, Virella G, Argraves WS, Lopes-Virella MF. Oxidized LDL immune complexes and oxidized LDL differentially affect the expression of genes involved with inflammation and survival in human U937 monocytic cells. Atherosclerosis 2008; 202:394-404. [PMID: 18597759 DOI: 10.1016/j.atherosclerosis.2008.05.032] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2008] [Revised: 05/09/2008] [Accepted: 05/12/2008] [Indexed: 01/22/2023]
Abstract
OBJECTIVE To compare the global effects of oxidized LDL (oxLDL) and oxLDL-containing immune complexes (oxLDL-IC) on gene expression in human monocytic cells and to identify differentially expressed genes involved with inflammation and survival. METHODS AND RESULTS U937 cells were treated with oxLDL-IC, oxLDL, Keyhole limpet hemocyanin immune complexes (KLH-IC), or vehicle for 4h. Transcriptome profiling was performed using DNA microarrays. oxLDL-IC uniquely affected the expression of genes involved with pro-survival (RAD54B, RUFY3, SNRPB2, and ZBTB24). oxLDL-IC also regulated many genes in a manner similar to KLH-IC. Functional categorization of these genes revealed that 39% are involved with stress responses, including the unfolded protein response which impacts cell survival, 19% with regulation of transcription, 10% with endocytosis and intracellular transport of protein and lipid, and 16% with inflammatory responses including regulation of I-kappaB /NF-kappaB cascade and cytokine activity. One gene in particular, HSPA6, greatly up-regulated by oxLDL-IC, was found to be required for the process by which oxLDL-IC augments IL1-beta secretion. The study also revealed genes uniquely up-regulated by oxLDL, including genes involved with growth inhibition (OKL38, NEK3, and FTH1), oxidoreductase activity (SPXN1 and HMOX1), and transport of amino acids and fatty acids (SLC7A11 and ADFP). CONCLUSIONS These findings highlight early transcriptional responses elicited by oxLDL-IC that may underlie its cytoprotective and pro-inflammatory effects. Cross-linking of Fc gamma receptors appears to be the trigger for most of the transcriptional responses to oxLDL-IC. The findings further strengthen the hypothesis that oxLDL and oxLDL-IC elicit disparate inflammatory responses and play distinct roles in the process of atherosclerosis.
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Affiliation(s)
- Samar M Hammad
- Department of Cell Biology and Anatomy, Medical University of South Carolina, 114 Doughty Street, 630B, P.O. Box 250776, Charleston, SC 29425, USA.
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Virella G, Lopes-Virella MF. Atherogenesis and the humoral immune response to modified lipoproteins. Atherosclerosis 2008; 200:239-46. [PMID: 18513726 DOI: 10.1016/j.atherosclerosis.2008.03.025] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2008] [Revised: 03/27/2008] [Accepted: 03/28/2008] [Indexed: 01/06/2023]
Abstract
Modified forms of LDL are immunogenic and activate both cell-mediated and humoral immune responses. Both types of responses are pro-inflammatory and are probably primary players in the perpetuation of the chronic inflammatory reaction characteristic of atherosclerosis. The immunologic response to modified LDL can be directed to MHC-II-associated peptides in the case of T helper cells, and to a variety of epitopes-modified lysine groups, modified phospholipids, proteins that become associated with oxidized LDL (such as beta2GP1)--in the case of B cell responses. T cell activation is likely to play a major role through cross-activation of macrophages. Humoral responses to modified LDL are pathogenic as a consequence of the formation of antigen-antibody complexes containing modified LDL and IgG antibodies. Those immune complexes induce cholesterol ester accumulation in macrophages and macrophage-like cells, and induce the release of pro-inflammatory cytokines, chemokines, oxygen active radicals, and matrix metalloproteinases from those cells. There is no conclusive evidence supporting a protective role for IgM antibodies in humans, possibly because autoantibodies to modified lipoproteins are predominantly of the IgG isotype.
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Affiliation(s)
- Gabriel Virella
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC 29425, United States.
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Wang J, Zhang C, Gong J, Zhu Y, Fu L, Wang X, Li K. Development of new enzyme-linked immunosorbent assay for oxidized lipoprotein(a) by using purified human oxidized lipoprotein(a) autoantibodies as capture antibody. Clin Chim Acta 2007; 385:73-8. [PMID: 17719023 DOI: 10.1016/j.cca.2007.06.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2007] [Revised: 06/28/2007] [Accepted: 06/30/2007] [Indexed: 12/31/2022]
Abstract
BACKGROUND Oxidized Lp(a) [ox-Lp(a)] has been reported to play more potent role than native Lp(a) in atherosclerosis. Ox-Lp(a), autoantibodies, and Lp(a) immune complexes have all been detected in vivo. Thus, the isolation of its autoantibodies and the investigation of ox-Lp(a) may provide a new means to explore the exact pathogenic role of ox-Lp(a). We isolated and identified human autoantibodies against ox-Lp(a) and developed a new ELISA for ox-Lp(a) by using autoantibodies as capture antibody. METHODS Ox-Lp(a) autoantibodies were isolated and identified from healthy subjects by affinity chromatography. 2 "sandwich" ELISAs were developed for measuring ox-Lp(a) level, using autoantibodies against ox-Lp(a) or rabbit antiserum against ox-LDL as the capture antibody and quantitating with monoclonal anti-apo(a) enzyme conjugate, respectively. Ox-Lp(a) levels were studied by both the ELISAs in 100 patients with coronary heart disease (CHD) and 100 control subjects. RESULTS The isolated ox-Lp(a) autoantibodies reacted with both apo(a) and apoB epitopes of Ox-Lp(a). Compared to control, plasma ox-Lp(a) levels in patients with CHD were significantly increased (ELISA using human autoantibodies: 24.3+/-33.4 vs. 8.4+/-9.3 microg/ml, P<0.0001; ELISA using antibodies against ox-LDL: 13.0+/-13.8 vs. 7.3+/-9.7 microg/ml, P<0.0001, respectively). Furthermore, a significantly positive relationship between ox-Lp(a) levels detected by 2 ELISAs was also found (R=0.78, P<0.0001). CONCLUSION We isolated human autoantibodies against ox-Lp(a), which can recognize both apo(a) and apoB epitopes of ox-Lp(a). The developed ELISA for ox-Lp(a) by using human auoantibodies may more accurately reflect the state of Lp(a) oxidation in vivo. Ox-Lp(a) levels increase in patients with CHD.
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Affiliation(s)
- Junjun Wang
- Department of Biochemistry, Jinling Hospital, Clinical School of Medicine College, Nanjing University, PR China
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Lopes-Virella MF, McHenry MB, Lipsitz S, Yim E, Wilson PF, Lackland DT, Lyons T, Jenkins AJ, Virella G. Immune complexes containing modified lipoproteins are related to the progression of internal carotid intima-media thickness in patients with type 1 diabetes. Atherosclerosis 2007; 190:359-69. [PMID: 16530770 DOI: 10.1016/j.atherosclerosis.2006.02.007] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2005] [Revised: 12/01/2005] [Accepted: 02/01/2006] [Indexed: 10/24/2022]
Abstract
Modified lipoproteins induce autoimmune responses including the synthesis of autoantibodies with pro-inflammatory characteristics. Circulating modified lipoprotein autoantibodies combine with circulating antigens and form immune complexes (IC). We now report the results of a study investigating the role of circulating IC containing modified lipoproteins in the progression of carotid intima-media thickness (IMT) in patients enrolled in the Epidemiology of Diabetes Interventions and Complications (EDIC) Trial, a follow-up study of the Diabetes Control and Complications Trial (DCCT). This cohort includes 1229 patients with type 1 diabetes in whom B-mode ultrasonography of internal and common carotid arteries was performed in 1994-1996 and in 1998-2000. Conventional CHD risk factors, antibodies against modified forms of LDL and modified lipoprotein IC were determined in 1050 of these patients from blood collected in 1996-1998. Cholesterol and apolipoprotein B content of IC (surrogate markers of modified ApoB-rich lipoproteins) were significantly higher in patients who showed progression of the internal carotid IMT than in those showing no progression, regression or mild progression. Multivariate linear and logistic regression modeling using conventional and non-conventional risk factors showed that the cholesterol content of IC was a significant positive predictor of internal carotid IMT progression. In conclusion these data demonstrate that increased levels of modified ApoB-rich IC are associated with increased progression of internal carotid IMT in the DCCT/EDIC cohort of type 1 diabetes.
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Saad AF, Virella G, Chassereau C, Boackle RJ, Lopes-Virella MF. OxLDL immune complexes activate complement and induce cytokine production by MonoMac 6 cells and human macrophages. J Lipid Res 2006; 47:1975-83. [PMID: 16804192 DOI: 10.1194/jlr.m600064-jlr200] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Oxidized low density lipoprotein (OxLDL) is immunogenic and induces autoimmune responses in humans. OxLDL antibodies are predominantly of the proinflammatory IgG1 and IgG3 isotypes. We tested the capacity of immune complexes prepared with copper-oxidized human LDL and affinity chromatography-purified human OxLDL antibodies [OxLDL-immune complexes (ICs)] to activate complement and to induce cytokine release by MonoMac 6 (MM6) cells and by primary human macrophages. The levels of C4d and C3a were significantly higher in human serum incubated with OxLDL-ICs than after incubation with OxLDL or OxLDL antibody, indicating complement activation by the classical pathway. MM6 cells and primary human macrophages were incubated with OxLDL-ICs, with or without prior conditioning with interferon-gamma. After 18 h of incubation, both MM6 cells and primary human macrophages released significantly higher levels of proinflammatory cytokines after incubation with OxLDL-ICs than after incubation with OxLDL or with OxLDL antibody, both in primed and unprimed cells. OxLDL-ICs were more potent activators of MM6 cells than keyhole limpet hemocyanin-ICs. Blocking Fc gamma receptor I (FcgammaRI) with monomeric IgG1 significantly depressed the response of MM6 cells to OxLDL-ICs. In conclusion, human OxLDL-ICs have proinflammatory properties, as reflected by their capacity to activate the classical pathway of complement and to induce proinflammatory cytokine release from MM6 cells and primary human macrophages.
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Affiliation(s)
- Antonio F Saad
- Ralph H. Johnson Department of Veterans Affairs Medical Center, Charleston, SC, USA
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Hammad SM, Taha TA, Nareika A, Johnson KR, Lopes-Virella MF, Obeid LM. Oxidized LDL immune complexes induce release of sphingosine kinase in human U937 monocytic cells. Prostaglandins Other Lipid Mediat 2006; 79:126-40. [PMID: 16516816 DOI: 10.1016/j.prostaglandins.2005.12.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2005] [Revised: 12/21/2005] [Accepted: 12/21/2005] [Indexed: 02/03/2023]
Abstract
The transformation of macrophages into foam cells is a critical event in the development of atherosclerosis. The most studied aspect of this process is the uptake of modified LDL through the scavenger receptors. Another salient aspect is the effect of modified LDL immune complexes on macrophages activation and foam cell formation. Macrophages internalize oxidized LDL immune complexes (oxLDL-IC) via the Fc-gamma receptor and transform into activated foam cells. In this study we examined the effect of oxLDL-IC on sphingosine kinase 1 (SK1), an enzyme implicated in mediating pro-survival and inflammatory responses through the generation of the signaling molecule sphingosine-1-phosphate (S1P). Intriguingly, oxLDL-IC, but not oxLDL alone, induced an immediate translocation and release of SK1 into the conditioned medium as evidenced by fluorescence confocal microscopy. Immunoblot analysis of cell lysates and conditioned medium revealed a decrease in intracellular SK1 protein levels accompanied by a concomitant increase in extracellular SK1 levels. Furthermore, measurement of S1P formation showed that the activity of cell-associated SK decreased in response to oxLDL-IC compared to oxLDL alone, whereas the activity of SK increased extracellularly. Blocking oxLDL-IC binding to Fc-gamma receptors resulted in decreased levels of extracellular S1P. The data also show that cell survival of human U937 cells exposed to oxLDL-IC increased compared to oxLDL alone. Exogenously added S1P further increased cell survival induced by oxLDL-IC. Taken together, these findings indicate that S1P may be generated extracellularly in response to modified LDL immune complexes and may therefore promote cell survival and prolong cytokine release by activated macrophages.
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Affiliation(s)
- Samar M Hammad
- Division of Endocrinology Diabetes & Medical Genetics, Medical University of South Carolina, 114 Doughty Street, 630B, PO Box 250776, Charleston, SC 29425, USA.
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Lopes-Virella MF, Thorpe SR, Derrick MB, Chassereau C, Virella G. The immunogenicity of modified lipoproteins. Ann N Y Acad Sci 2005; 1043:367-78. [PMID: 16037258 DOI: 10.1196/annals.1333.043] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The immunogenicity of modified low-density lipoprotein (mLDL) has been demonstrated both in laboratory animals and humans. Circulating human mLDL antibodies, purified by affinity chromatography, are predominantly of the IgG isotype, subclasses 1 and 3. The purified antibodies react with malondialdehyde-lysine and carboxymethyl-lysine epitopes, but also recognize minimally modified forms of LDL that do not contain significant amounts of those two epitopes. The quantitative assays of mLDL and mLDL antibodies in serum samples by enzymoimmunoassay (EIA) are unreliable owing to the interference of preformed circulating immune complexes (CICs). Isolation of CICs by precipitation with low concentrations of polyethylene glycol followed by analysis of antigens and antibodies contained in the precipitates is a technically complex approach, but one that yields valuable data. With this approach we have confirmed that the IgG antibodies involved in IC formation belong to the proinflammatory IgG1 and IgG3 isotypes, have a higher avidity than those that remain unbound in the supernatant after CIC precipitation, and are of higher avidity in diabetic patients with macroalbuminuria than in those with normal albuminuria. We have also developed capture assays for different forms of mLDL. These assays have shown a significant enrichment in mLDL of the precipitated ICs. The enrichment is also more pronounced in the CICs obtained from diabetic patients with macroalbuminuria. In conclusion, isolation and characterization of LDL-ICs appears to yield information of significant value that is not derived from other approaches to measure LDL modifications and their corresponding antibodies in humans.
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Affiliation(s)
- Maria F Lopes-Virella
- Strom Thurmond Research Building, 114 Doughty Street, Room 529, Charleston, SC 29425, USA.
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Virella G, Derrick MB, Pate V, Chassereau C, Thorpe SR, Lopes-Virella MF. Development of capture assays for different modifications of human low-density lipoprotein. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 2005; 12:68-75. [PMID: 15642987 PMCID: PMC540197 DOI: 10.1128/cdli.12.1.68-75.2005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Antibodies to malondialdehyde (MDA)-modified low-density lipoprotein (LDL), copper-oxidized LDL (oxLDL), Nepsilon(carboxymethyl) lysine (CML)-modified LDL, and advanced glycosylation end product (AGE)-modified LDL were obtained by immunization of rabbits with in vitro-modified human LDL preparations. After absorption of apolipoprotein B (ApoB) antibodies, we obtained antibodies specific for each modified lipoprotein with unique patterns of reactivity. MDA-LDL antibodies reacted strongly with MDA-LDL and also with oxLDL. CML-LDL antibodies reacted strongly with CML-LDL and also AGE-LDL. oxLDL antibodies reacted with oxLDL but not with MDA-LDL, and AGE-LDL antibodies reacted with AGE-LDL but not with CML-LDL. Capture assays were set with each antiserum, and we tested their ability to capture ApoB-containing lipoproteins isolated from precipitated immune complexes (IC) and from the supernatants remaining after IC precipitation (free lipoproteins). All antibodies captured lipoproteins contained in IC more effectively than free lipoproteins. Analysis of lipoproteins in IC by gas chromatography-mass spectrometry showed that they contained MDA-LDL and CML-LDL in significantly higher concentrations than free lipoproteins. A significant correlation (r=0.706, P<0.019) was obtained between the MDA concentrations determined by chemical analysis and by the capture assay of lipoproteins present in IC. In conclusion, we have developed capture assays for different LDL modifications in human ApoB/E lipoprotein-rich fractions isolated from precipitated IC. This approach obviates the interference of IC in previously reported modified LDL assays and allows determination of the degree of modification of LDL with greater accuracy.
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Affiliation(s)
- Gabriel Virella
- Medical University of South Carolina, Department of Microbiology and Immunology, 173 Ashley Ave., PO Box 250504, Charleston, SC 29425, USA.
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