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Wells AT, Shen MM, Binrouf RH, D'Amico AE, Bossardi Ramos R, Lennartz MR. Identification of Myeloid Protein Kinase C - Epsilon as a Novel Atheroprotective Gene. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.12.09.627650. [PMID: 39713428 PMCID: PMC11661236 DOI: 10.1101/2024.12.09.627650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2024]
Abstract
Background Atherosclerosis is a lipid mediated chronic inflammatory disease driven my macrophages (MØ). Protein Kinase C - epsilon (PKCɛ) is is a serine/threonine kinase involved in diverse cellular processes such as migration, growth, differentiation, and survival. PKCɛ is known to act in a context dependent manner within heart, however, its role in atherosclerosis is unknown. Methods Bone marrow derived MØ from global PKCɛ KO mice were examined for impact of lipid metabolism and inflammatory factor secretion. Public geneset analysis assessed raw counts of PKCɛ to determine translational relevance. To determine the function myeloid PKCɛ on atherosclerosis a novel murine model was generated using LysM Cre technology. After its characterization, human-like hypercholesterolemia was induced to assess plaque morphology in WT mice or mice lacking myeloid PKCɛ. Results Public geneset analysis of human atherosclerotic plaque tissue revealed that PKCɛ expression is inversely correlated with plaque size and vulnerability. Similarly, peritoneal MØ from hypercholesterolemic mice have significantly lower PKCɛ expression. As MØ play a major role in atherogenesis, we generated a mouse strain with PKCɛ selectively deleted in the myeloid lineage (mɛKO). qPCR revealed no basal differences between genotypes in the expression of lipid uptake receptors, efflux transporters, or inflammatory markers. However, upon lipid loading, mɛKO MØs retained significantly more cholesterol than WT. Human-like hypercholesterolemia was induced in WT and mɛKO mice and assessed for lesion area and plaque morphology in aortic arches and aortic roots. We found that, compared to WT, the lesion area in mɛKO mice was significantly larger, more necrotic, had larger foam cells, and thinner collagen caps. Conclusions Loss of myeloid PKCɛ promotes atherosclerosis as determined by larger lesions, more necrosis, thinner plaque caps). Together, these data identify myeloid PKCɛ as a novel atheroprotective gene, laying the foundation for mechanistic studies on the signaling networks responsible for the phenotype. Highlights A novel murine model in which PKCɛ is floxed (PKCɛ fl/fl ) on both alleles haas been generated, backcrossed, and deposited into Jackson Laboratories. PKCε fl/fl mice have been crossed with those on the LysM Cre background thereby deleting PKCε from myeloid cells (mεKO). Deletion of PKCε has no basal affects on other PKC isoforms, lipid handling markers, or inflammatory markers.Upon stimulation with lopid loading in vitro or hypercholesterolemia in vivo, mεKO BMDMs retain more cholesterol and mεKO mice develop a more vulnerable plaque phenotype (i.e. larger lesions, more necrosis, thimmer plaque caps).These findings provide a rationale for the need to identify mediators in the PKCε signaling pathway responsible for protection against vulnerable plaques in atherosclerosis; potentially aiding in the development of preventative and therapeutic treatments.
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Zhang Q, Liu H, Zhang M, Liu F, Liu T. Identification of co-expressed central genes and transcription factors in atherosclerosis-related intracranial aneurysm. Front Neurol 2023; 14:1055456. [PMID: 36937519 PMCID: PMC10017537 DOI: 10.3389/fneur.2023.1055456] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 02/06/2023] [Indexed: 03/06/2023] Open
Abstract
Background Numerous clinical studies have shown that atherosclerosis is one of the risk factors for intracranial aneurysms. Calcifications in the intracranial aneurysm walls are frequently correlated with atherosclerosis. However, the pathogenesis of atherosclerosis-related intracranial aneurysms remains unclear. This study aims to investigate this mechanism. Methods The Gene Expression Omnibus (GEO) database was used to download the gene expression profiles for atherosclerosis (GSE100927) and intracranial aneurysms (GSE75436). Following the identification of the common differentially expressed genes (DEGs) of atherosclerosis and intracranial aneurysm, the network creation of protein interactions, functional annotation, the identification of hub genes, and co-expression analysis were conducted. Thereafter, we predicted the transcription factors (TF) of hub genes and verified their expressions. Results A total of 270 common (62 downregulated and 208 upregulated) DEGs were identified for subsequent analysis. Functional analyses highlighted the significant role of phagocytosis, cytotoxicity, and T-cell receptor signaling pathways in this disease progression. Eight hub genes were identified and verified, namely, CCR5, FCGR3A, IL10RA, ITGAX, LCP2, PTPRC, TLR2, and TYROBP. Two TFs were also predicted and verified, which were IKZF1 and SPI1. Conclusion Intracranial aneurysms are correlated with atherosclerosis. We identified several hub genes for atherosclerosis-related intracranial aneurysms and explored the underlying pathogenesis. These discoveries may provide new insights for future experiments and clinical practice.
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Affiliation(s)
- Quan Zhang
- Department of Neurology, Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Hengfang Liu
- Department of Neurology, Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
- *Correspondence: Hengfang Liu
| | - Min Zhang
- Department of Neurology, Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Fang Liu
- Department of Neurology, Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Tiantian Liu
- Department of Neurology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
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Lorey MB, Öörni K, Kovanen PT. Modified Lipoproteins Induce Arterial Wall Inflammation During Atherogenesis. Front Cardiovasc Med 2022; 9:841545. [PMID: 35310965 PMCID: PMC8927694 DOI: 10.3389/fcvm.2022.841545] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 01/26/2022] [Indexed: 12/15/2022] Open
Abstract
Circulating apolipoprotein B-containing lipoproteins, notably the low-density lipoproteins, enter the inner layer of the arterial wall, the intima, where a fraction of them is retained and modified by proteases, lipases, and oxidizing agents and enzymes. The modified lipoproteins and various modification products, such as fatty acids, ceramides, lysophospholipids, and oxidized lipids induce inflammatory reactions in the macrophages and the covering endothelial cells, initiating an increased leukocyte diapedesis. Lipolysis of the lipoproteins also induces the formation of cholesterol crystals with strong proinflammatory properties. Modified and aggregated lipoproteins, cholesterol crystals, and lipoproteins isolated from human atherosclerotic lesions, all can activate macrophages and thereby induce the secretion of proinflammatory cytokines, chemokines, and enzymes. The extent of lipoprotein retention, modification, and aggregation have been shown to depend largely on differences in the composition of the circulating lipoprotein particles. These properties can be modified by pharmacological means, and thereby provide opportunities for clinical interventions regarding the prevention and treatment of atherosclerotic vascular diseases.
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Affiliation(s)
- Martina B. Lorey
- Atherosclerosis Research Laboratory, Wihuri Research Institute, Helsinki, Finland
- Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Katariina Öörni
- Atherosclerosis Research Laboratory, Wihuri Research Institute, Helsinki, Finland
- Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
- *Correspondence: Katariina Öörni
| | - Petri T. Kovanen
- Atherosclerosis Research Laboratory, Wihuri Research Institute, Helsinki, Finland
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Karpouzas GA, Bui VL, Ronda N, Hollan I, Ormseth SR. Biologics and atherosclerotic cardiovascular risk in rheumatoid arthritis: a review of evidence and mechanistic insights. Expert Rev Clin Immunol 2021; 17:355-374. [PMID: 33673792 DOI: 10.1080/1744666x.2021.1899809] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Introduction: Cardiovascular disease is a leading comorbidity in rheumatoid arthritis. Timely introduction of biologic therapies in a treat-to-target approach has optimized disease-related outcomes and attenuated accrual of comorbidities, including cardiovascular risk.Areas covered: A literature search in MEDLINE (via PubMed) was performed between January 2009 and November 2020. This manuscript explores recent developments in atherosclerotic cardiovascular risk in RA compared with non-RA individuals; it synopsizes differences in vascular function and inflammation, prevalence, burden, vulnerability, and progression of atherosclerotic plaque and their underlying cellular and molecular mechanisms. Finally, it reviews the recent literature on cardioprotective benefits of biologics and draws mechanistic links with inhibition of new plaque formation, stabilization of high-risk lesions and improvement in endothelial function, arterial stiffness, lipid metabolism, and traditional cardiac risk factors.Expert opinion: Increasing evidence points to a solid cardioprotective influence of earlier, longer, and ongoing use of biologic treatments in RA. Nevertheless, the precise mechanistic effects of plaque progression and remodeling, vascular stiffness, endothelial dysfunction, lipid metabolism, and traditional cardiac risk factors are less rigorously characterized.
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Affiliation(s)
- George A Karpouzas
- Division of Rheumatology, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Viet L Bui
- Division of Rheumatology, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Nicoletta Ronda
- Department of Food and Drug, University of Parma, Parma, Italy
| | - Ivana Hollan
- The Norwegian University of Science and Technology, Gjøvik, Norway.,Beitostølen Sport and Health Centre, Beitostølen, Norway
| | - Sarah R Ormseth
- Division of Rheumatology, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, USA
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The Potential Role of Citrus limon Powder as a Natural Feed Supplement to Boost the Productive Performance, Antioxidant Status, and Blood Biochemistry of Growing Rabbits. Animals (Basel) 2019; 9:ani9070426. [PMID: 31284654 PMCID: PMC6680595 DOI: 10.3390/ani9070426] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 07/02/2019] [Accepted: 07/04/2019] [Indexed: 01/17/2023] Open
Abstract
The current study examined the influence of Citrus limon (dry lemon) on the hemato-biochemical profiles, and antioxidant indices of growing rabbits. Forty-eight growing New Zealand White rabbits (age, eight weeks; weight, 1543.33 ± 25 g) were allocated into three groups (16 animals each), the first group was (control) fed a basal diet, whereas the second and third groups were supplemented with dried lemon, 1% or 2% DLP, respectively. A GC-MS analysis of more than 27 active constituents was performed. Feed conversion efficiency was (p < 0.05) better with diets containing 1% or 2% dry lemon, compared to the control group. Hematological indexes were increased significantly with the addition of DLP compared to those in the control group. Adding 1% or 2% dry lemon to rabbit diet increased (p < 0.05) enzymatic and non-enzymatic antioxidant activities (TAC, SOD, GSH, GST, and CAT) in serum and liver tissues. Taken together, these data reveal the advantages and antioxidant effects of dry lemon supplementation for growing rabbits once supplemented at a maximum of 2% in their daily diet.
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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: 0.7] [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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Ye Y, Wu T, Zhang T, Han J, Habazi D, Saxena R, Mohan C. Elevated oxidized lipids, anti-lipid autoantibodies and oxidized lipid immune complexes in active SLE. Clin Immunol 2019; 205:43-48. [PMID: 31075396 DOI: 10.1016/j.clim.2019.05.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 05/03/2019] [Accepted: 05/05/2019] [Indexed: 01/07/2023]
Abstract
BACKGROUND Here, we explore the serum levels of anti-oxidized lipid autoantibodies as well as immune complexes in patients with SLE and determine their correlation with disease. METHODS Serum levels of oxidized-LDL immune complexes, autoantibodies to dsDNA, ox-LDL, MDA-LDL, 9-HODE, 13-HODE and POVPC were detected by ELISA in 64 SLE patients and 9 healthy controls. RESULTS Active SLE patients exhibited increased serum levels of autoantibodies compared to healthy controls, including anti-MDA-LDL-IgG (p = .003), anti-ox-LDL-IgG (p = .004), anti-9-HODE-IgG (p = .001), anti-13-HODE-IgG (p = .0003), anti-POVPC-IgG (p = .001) and ox-LDL-IC (p = .003). Serum anti-ox-LDL-IgG was positively correlated with SLEDAI (r = 0.34; p = .01), and negatively with C3 (r = -0.40; p = .01). Anti-9-HODE-IgG and anti-POVPC-IgG were positively correlated with SLEDAI and negatively with C4. CONCLUSIONS Active SLE patients exhibit significantly increased serum levels of IgG anti-oxidized-lipid autoantibodies. Coordinated elevation of oxidized lipids, autoantibodies to these lipids, and immune complexes of these lipid-antibody components could potentially serve as pathogenic drivers and serum markers of SLE disease activity.
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Affiliation(s)
- Yujin Ye
- Department of Internal Medicine and Immunology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Rheumatology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, China
| | - Tianfu Wu
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
| | - Ting Zhang
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
| | - Jie Han
- Department of Internal Medicine and Immunology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Deena Habazi
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
| | - Ramesh Saxena
- Department of Internal Medicine and Immunology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Chandra Mohan
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA.
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Nuti F, Gallo A, Real-Fernandez F, Rentier C, Rossi G, Piarulli F, Traldi P, Carganico S, Rovero P, Lapolla A, Papini AM. Study of Aberrant Modifications in Peptides as a Test Bench to Investigate the Immunological Response to Non-Enzymatic Glycation. Folia Biol (Praha) 2019; 65:195-202. [PMID: 31903893 DOI: 10.14712/fb2019065040195] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2024]
Abstract
A side effect of diabetes is formation of glycated proteins and, from them, production of advanced early glycation end products that could determine aberrant immune responses at the systemic level. We investigated a relevant aberrant post-translational modification (PTM) in diabetes based on synthetic peptides modified on the lysine side chain residues with 1-deoxyfructopyranosyl moiety as a possible modification related to glycation. The PTM peptides were used as molecular probes for detection of possible specific autoantibodies developed by diabetic patients. The PDC-E2(167-186) sequence from the pyruvate dehydrogenase complex was selected and tested as a candidate peptide for antibody detection. The structure-based designed type I' β-turn CSF114 peptide was also used as a synthetic scaffold. Twenty-seven consecutive type 1 diabetic patients and 29 healthy controls were recruited for the study. In principle, the 'chemical reverse approach', based on the use of patient sera to screen the synthetic modified peptides, leads to the identification of specific probes able to characterize highly specific autoantibodies as disease biomarkers of autoimmune disorders. Quite surprisingly, both peptides modified with the (1-deoxyfructosyl)-lysine did not lead to significant results. Both IgG and IgM differences between the two populations were not significant. These data can be rationalized considering that i) IgGs in diabetic subjects exhibit a high degree of glycation, leading to decreased functionality; ii) IgGs in diabetic subjects exhibit a privileged response vs proteins containing advanced glycation products (e.g., methylglyoxal, glyoxal, glucosone, hydroimidazolone, dihydroxyimidazolidine) and only a minor one with respect to (1-deoxyfructosyl)-lysine.
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Affiliation(s)
- F Nuti
- Laboratory of Peptide and Protein Chemistry and Biology, Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino, Italy
| | - A Gallo
- Diabetology and Dietetics, Department of Medicine (DIMED), University of Padova, Padova, Italy
| | - F Real-Fernandez
- Laboratory of Peptide and Protein Chemistry and Biology, Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino, Italy
| | - C Rentier
- Laboratory of Peptide and Protein Chemistry and Biology, Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino, Italy
- PeptLab@UCP Platform and Laboratory of Chemical Biology EA4505, University Paris-Seine, Cergy-Pontoise CEDEX, France
| | - G Rossi
- Laboratory of Peptide and Protein Chemistry and Biology, Department of NeuroFarBa, University of Florence, Sesto Fiorentino, Italy
- Pharma Quality Europe PQE SrL, Località Prulli, Firenze, Italy
| | - F Piarulli
- Diabetology and Dietetics, Department of Medicine (DIMED), University of Padova, Padova, Italy
| | - P Traldi
- Istituto di Ricerca Pediatrica, Città della Speranza, Padova, Italy
| | - S Carganico
- Laboratory of Peptide and Protein Chemistry and Biology, Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino, Italy
- Pharma Quality Europe PQE SrL, Località Prulli, Firenze, Italy
| | - P Rovero
- Laboratory of Peptide and Protein Chemistry and Biology, Department of NeuroFarBa, University of Florence, Sesto Fiorentino, Italy
| | - A Lapolla
- Diabetology and Dietetics, Department of Medicine (DIMED), University of Padova, Padova, Italy
| | - A M Papini
- Laboratory of Peptide and Protein Chemistry and Biology, Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino, Italy
- PeptLab@UCP Platform and Laboratory of Chemical Biology EA4505, University Paris-Seine, Cergy-Pontoise CEDEX, France
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Immune complexes containing malondialdehyde (MDA) LDL induce apoptosis in human macrophages. Clin Immunol 2018; 187:1-9. [PMID: 28689783 DOI: 10.1016/j.clim.2017.06.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [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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10
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Sakai-Kato K, Sakurai M, Takechi-Haraya Y, Nanjo K, Goda Y. Involvement of scavenger receptor class B type 1 and low-density lipoprotein receptor in the internalization of liposomes into HepG2 cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:2253-2258. [DOI: 10.1016/j.bbamem.2017.09.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 08/06/2017] [Accepted: 09/05/2017] [Indexed: 11/30/2022]
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Li Y, Lu Z, Huang Y, Lopes-Virella MF, Virella G. F(ab′)2 fragments of anti-oxidized LDL IgG attenuate vascular inflammation and atherogenesis in diabetic LDL receptor-deficient mice. Clin Immunol 2016; 173:50-56. [DOI: 10.1016/j.clim.2016.07.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 07/18/2016] [Accepted: 07/21/2016] [Indexed: 10/21/2022]
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Impact of Chronic Glucocorticoid Treatment on Cardiovascular Risk Profile in Patients with Systemic Lupus Erythematosus. J Clin Rheumatol 2016; 22:8-12. [PMID: 26693620 DOI: 10.1097/rhu.0000000000000335] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Systemic lupus erythematosus is highly associated with premature atherosclerosis and cardiovascular events. The origin of this subclinical atherosclerosis has been attributed mainly to the inflammatory nature of the disease. OBJECTIVE To assess the effect of long-term use of glucocorticoids on cardiovascular risk in patients with systemic lupus erythematosus. MATERIAL AND METHODS We conducted a registry-based retrospective cohort study. We determined 2 periods: (1) Time 0, that is, time of diagnosis and (2) time 1, that is, when the study was finalized. At both times, the cardiovascular risk was evaluated using the Framingham scale and their scores were compared. Afterward, the change magnitude between the 2 times was evaluated and associated with the cumulative glucocorticoids dose. RESULTS One hundred one patients were included. The mean ± SD age was 26.5 ± 5 years. Length of disease evolution was of 7.8 ± 4.9 years. There was an 8-point increase in the Framingham score, from -8.1 ± 4 to 0.8 ± 7; P < 0.0001. The correlation between the magnitude of the increase in Framingham score and their corresponding cumulative dose showed a coefficient of 0.88; P < 0.001. CONCLUSIONS The glucocorticoids are a primary factor that influences cardiovascular risk. There is a directly proportional relationship between the cumulative glucocorticoid dose and the increase in cardiovascular risk.
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Akhter F, Salman Khan M, Faisal M, Alatar AA, Ahmad S. Detection of Circulating Auto-Antibodies Against Ribosylated-LDL in Diabetes Patients. J Clin Lab Anal 2016; 31. [PMID: 27561427 DOI: 10.1002/jcla.22039] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Accepted: 07/23/2016] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND This study analyzes effect of glycation on ApoB-100 residues by D-ribose as D-ribosylated-glycated LDL might be responsible for the cause of diabetes mellitus because of its far higher antigenic ability. The binding characteristics of circulating auto-antibodies in type 1 and type 2 diabetes patients against native and modified LDL were assessed. METHODS T1 Diabetes (n = 43), T2 diabetes patients (n = 100) were examined by direct binding ELISA as well as inhibition ELISA, were compared with healthy age-matched controls (n = 50). RESULTS High degree of specific binding was observed by 74.42% of T1 diabetes and 45.0% of T2 diabetes patient's sera toward glycated LDL, in comparison to its native analog. Competitive inhibition ELISA reiterates the direct binding results. Furthermore, ketoamine content, Hydroxymethylfurfural (HMF) content and carbonyl content were also estimated in patient's sera healthy subjects. The increase in total serum protein carbonyl levels in the diabetes patients was largely due to an increase in oxidative stress. The increase in ketoamine as well as HMF content inpatients sera than healthy subjects is an agreement of induced glycation reaction in patients than healthy subjects. CONCLUSION D-ribosylated-LDL has resulted in structural perturbation causing generation of neo-antigenic epitopes that are better antigens for antibodies in T1 and T2 diabetes patients.
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Affiliation(s)
- Firoz Akhter
- Department of Bio-Sciences, Integral University, Lucknow, India
| | - M Salman Khan
- Department of Bio-Sciences, Integral University, Lucknow, India
| | - Mohammad Faisal
- Department of Botany & Microbiology, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia
| | - Abdulrahman A Alatar
- Department of Botany & Microbiology, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia
| | - Saheem Ahmad
- Department of Bio-Sciences, Integral University, Lucknow, India
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Tanigaki K, Sundgren N, Khera A, Vongpatanasin W, Mineo C, Shaul PW. Fcγ receptors and ligands and cardiovascular disease. Circ Res 2015; 116:368-84. [PMID: 25593280 DOI: 10.1161/circresaha.116.302795] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Fcγ receptors (FcγRs) classically modulate intracellular signaling on binding of the Fc region of IgG in immune response cells. How FcγR and their ligands affect cardiovascular health and disease has been interrogated recently in both preclinical and clinical studies. The stimulation of activating FcγR in endothelial cells, vascular smooth muscle cells, and monocytes/macrophages causes a variety of cellular responses that may contribute to vascular disease pathogenesis. Stimulation of the lone inhibitory FγcR, FcγRIIB, also has adverse consequences in endothelial cells, antagonizing NO production and reparative mechanisms. In preclinical disease models, activating FcγRs promote atherosclerosis, whereas FcγRIIB is protective, and activating FcγRs also enhance thrombotic and nonthrombotic vascular occlusion. The FcγR ligand C-reactive protein (CRP) has undergone intense study. Although in rodents CRP does not affect atherosclerosis, it causes hypertension and insulin resistance and worsens myocardial infarction. Massive data have accumulated indicating an association between increases in circulating CRP and coronary heart disease in humans. However, Mendelian randomization studies reveal that CRP is not likely a disease mediator. CRP genetics and hypertension warrant further investigation. To date, studies of genetic variants of activating FcγRs are insufficient to implicate the receptors in coronary heart disease pathogenesis in humans. However, a link between FcγRIIB and human hypertension may be emerging. Further knowledge of the vascular biology of FcγR and their ligands will potentially enhance our understanding of cardiovascular disorders, particularly in patients whose greater predisposition for disease is not explained by traditional risk factors, such as individuals with autoimmune disorders.
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Affiliation(s)
- Keiji Tanigaki
- From the Department of Pediatrics, Center for Pulmonary and Vascular Biology (K.T., N.S., C.M., P.W.S.), and Division of Cardiology, Department of Internal Medicine (A.K., W.V.), University of Texas Southwestern Medical Center, Dallas
| | - Nathan Sundgren
- From the Department of Pediatrics, Center for Pulmonary and Vascular Biology (K.T., N.S., C.M., P.W.S.), and Division of Cardiology, Department of Internal Medicine (A.K., W.V.), University of Texas Southwestern Medical Center, Dallas
| | - Amit Khera
- From the Department of Pediatrics, Center for Pulmonary and Vascular Biology (K.T., N.S., C.M., P.W.S.), and Division of Cardiology, Department of Internal Medicine (A.K., W.V.), University of Texas Southwestern Medical Center, Dallas
| | - Wanpen Vongpatanasin
- From the Department of Pediatrics, Center for Pulmonary and Vascular Biology (K.T., N.S., C.M., P.W.S.), and Division of Cardiology, Department of Internal Medicine (A.K., W.V.), University of Texas Southwestern Medical Center, Dallas
| | - Chieko Mineo
- From the Department of Pediatrics, Center for Pulmonary and Vascular Biology (K.T., N.S., C.M., P.W.S.), and Division of Cardiology, Department of Internal Medicine (A.K., W.V.), University of Texas Southwestern Medical Center, Dallas
| | - Philip W Shaul
- From the Department of Pediatrics, Center for Pulmonary and Vascular Biology (K.T., N.S., C.M., P.W.S.), and Division of Cardiology, Department of Internal Medicine (A.K., W.V.), University of Texas Southwestern Medical Center, Dallas.
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Akhter F, Khan MS, Ahmad S. Acquired immunogenicity of calf thymus DNA and LDL modified by D-ribose: a comparative study. Int J Biol Macromol 2014; 72:1222-7. [PMID: 25450543 DOI: 10.1016/j.ijbiomac.2014.10.034] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 10/15/2014] [Accepted: 10/17/2014] [Indexed: 12/13/2022]
Abstract
Glycation of biologically important macromolecules leads to the establishment of advanced glycation end products (AGEs) having significant role in the pathophysiology of various diseases. d-Ribose, is a highly reactive pentose sugar resulting in the rapid formation of AGEs. Formation of d-ribose derived glycated DNA and LDL has been previously demonstrated; however no comparative, extensive studies have been performed to assess the immunogenicity of d-ribose glycated calf thymus DNA (CT-DNA) and LDL. In the present study, the results showed that animals immunized with d-ribose modified CT-DNA and LDL induced antibodies as detected by direct binding and competition ELISA. The modified CT-DNA and LDL were found to be highly immunogenic, eliciting high titer immunogen-specific antibodies, while the native forms of DNA was almost non-immunogenic. The induced antibodies from modified CT-DNA and LDL exhibited wide range of heterogeneity in recognizing various nucleic acid conformers, DNA bases and amino acids. Furthermore, Serum antibodies from diabetes and diabetes atherosclerosis patients were screened for their binding to native CT-DNA, LDL and glycated CT-DNA, LDL. Glycated CT-DNA showed almost equivalent binding to both diabetes and diabetic atherosclerosis group while high recognition was observed when glycated LDL was used as an antigen.
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Affiliation(s)
- Firoz Akhter
- Department of Bio-Sciences, Integral University, Lucknow, 226026, India; Department of Bio-Engineering, Integral University, Lucknow, 226026, India
| | - M Salman Khan
- Department of Bio-Sciences, Integral University, Lucknow, 226026, India
| | - Saheem Ahmad
- Department of Bio-Sciences, Integral University, Lucknow, 226026, India.
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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: 70] [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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Low density lipoprotein-containing circulating immune complexes: role in atherosclerosis and diagnostic value. BIOMED RESEARCH INTERNATIONAL 2014; 2014:205697. [PMID: 25054132 PMCID: PMC4087281 DOI: 10.1155/2014/205697] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 05/29/2014] [Accepted: 06/06/2014] [Indexed: 11/17/2022]
Abstract
It has been suggested that low density lipoprotein-containing circulating immune complexes (LDL-CIC) play a role in atherogenesis and are involved in the formation of early atherosclerotic lesion. These complexes, as well as anti-LDL autoantibodies, have been found in the blood and in the atherosclerotic lesions of patients with different cardiovascular diseases, as well as in the blood of animals with experimental atherosclerosis. It can be suggested that the presence of anti-LDL antibodies in the blood is a result of immune response induced by lipoprotein modification. LDL-CIC differs from native LDL in many aspects. It has much lower sialic acid content, smaller diameter, and higher density and is more electronegative than native LDL. Fraction of LDL-CICs is fundamental to the serum atherogenicity manifested at the cellular level. LDL-CIC, unlike native LDL, is able to induce intracellular accumulation of neutral lipids, especially esterified cholesterol, in cells cultured from uninvolved human aortic intima and in macrophage cultures. After removal of LDL-CIC, the CHD patient's sera lose their atherogenic properties. Titer of LDL-CIC in blood serum significantly correlates with progression of atherosclerosis in human in vivo and has the highest diagnostic value among other measured serum lipid parameters. Elevated CIC-cholesterol might well be a possible risk factor of coronary atherosclerosis.
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Lipoproteínas modificadas como marcadores de riesgo cardiovascular en la diabetes mellitus. ACTA ACUST UNITED AC 2013; 60:518-28. [DOI: 10.1016/j.endonu.2012.12.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 12/17/2012] [Accepted: 12/19/2012] [Indexed: 11/17/2022]
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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: 2.1] [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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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: 3.3] [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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Fitrolaki DM, Dimitriou H, Kalmanti M, Briassoulis G. CD64-Neutrophil expression and stress metabolic patterns in early sepsis and severe traumatic brain injury in children. BMC Pediatr 2013; 13:31. [PMID: 23452299 PMCID: PMC3599547 DOI: 10.1186/1471-2431-13-31] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 02/21/2013] [Indexed: 11/24/2022] Open
Abstract
Background Critical illness constitutes a serious derangement of metabolism. The aim of our study was to compare acute phase metabolic patterns in children with sepsis (S) or severe sepsis/septic shock (SS) to those with severe traumatic brain injury (TBI) and healthy controls (C) and to evaluate their relations to neutrophil, lymphocyte and monocyte expressions of CD64 and CD11b. Methods Sixty children were enrolled in the study. Forty-five children with systemic inflammatory response syndrome (SIRS) were classified into three groups: TBI (n = 15), S (n = 15), and SS (n = 15). C consisted of 15 non- SIRS patients undergoing screening tests for minor elective surgery. Blood samples were collected within 6 hours after admission for flow cytometry of neutrophil, lymphocyte and monocyte expression of CD64 and CD11b (n = 60). Procalcitonin (PCT), C-reactive protein (CRP), glucose, triglycerides (TG), total cholesterol (TC), high (HDL) or low-density-lipoproteins (LDL) were also determined in all groups, and repeated on day 2 and 3 in the 3 SIRS groups (n = 150). Results CRP, PCT and TG (p < 0.01) were significantly increased in S and SS compared to TBI and C; glucose did not differ among critically ill groups. Significantly lower were the levels of TC, LDL, and HDL in septic groups compared to C and to moderate changes in TBI (p < 0.0001) but only LDL differed between S and SS (p < 0.02). Among septic patients, PCT levels declined significantly (p < 0.02) with time, followed by parallel decrease of HDL (p < 0.03) and increase of TG (p < 0.02) in the SS group. Neutrophil CD64 (nCD64) expression was higher in patients with SS (81.2%) and S (78.8%) as compared to those with TBI (5.5%) or C (0.9%, p < 0.0001). nCD64 was positively related with CRP, PCT, glucose, and TG (p < 0.01) and negatively with TC, LDL, and HDL (p < 0.0001), but not with severity of illness, hematologic indices, length of stay or mechanical ventilation duration. Conclusions In sepsis, the early stress-metabolic pattern is characterized by a high (nCD64, glucose, TG) - low (TC, HDL, LDL) combination in contrast to the moderate pattern of TBI in which only glucose increases combined with a moderate cholesterol - lipoprotein decrease. These early metabolic patterns persist the first 3 days of acute illness and are associated with the acute phase CD64 expression on neutrophils.
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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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Modulation of immune cell proliferation and chemotaxis towards CC chemokine ligand (CCL)-21 and CXC chemokine ligand (CXCL)-12 in undenatured whey protein-treated mice. J Nutr Biochem 2012; 23:1640-6. [DOI: 10.1016/j.jnutbio.2011.11.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 11/22/2011] [Accepted: 11/22/2011] [Indexed: 12/15/2022]
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Sobenin IA, Karagodin VP, Melnichenko ACAC, Bobryshev YV, Orekhov AN. Diagnostic and prognostic value of low density lipoprotein-containing circulating immune complexes in atherosclerosis. J Clin Immunol 2012; 33:489-95. [PMID: 23073618 DOI: 10.1007/s10875-012-9819-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 10/09/2012] [Indexed: 11/29/2022]
Abstract
Recently, it has been shown that increased level of LDL-containing circulating immune complexes (LDL-CIC) possess high diagnostic significance in clinically manifested atherosclerosis, but little is known about its diagnostic and prognostic significance in early atherosclerosis. Two-years prospective study was performed in 98 asymptomatic men aged 40-74. The rate of atherosclerosis progression was estimated by high-resolution B-mode ultrasonography as the increase in intima-media thickness (IMT) of common carotid arteries. The patients with elevated baseline levels of LDL-CIC were characterized by significantly higher levels of total and LDL cholesterol as well as significantly increased mean IMT of common carotid arteries. Among all baseline lipid parameters, only LDL-CIC and LDL cholesterol were contingent with the extent of early carotid atherosclerosis (p = 0.042 and p = 0.049, respectively) and had the highest levels of relative risk and odds ratio. During the follow up, significant IMT increase was registered in 53.1 % (n = 52) patients, IMT significant reduction was observed in 21.4 % (n = 21) patients. The increased levels of LDL-CIC, total serum cholesterol and LDL cholesterol had similar prognostic significance with the respect of atherosclerosis progression. The normal level of LDL-CIC (below than 16.0 μg/ml) was the only lipid parameter that predicted the absence of carotid atherosclerosis progression for two following years at prognostic value of 78.3 %. The results of the study allow assuming that LDL-CIC level may be employed not only as a marker of early atherosclerosis, but also has a sufficient prognostic value for clinical implications.
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Affiliation(s)
- Igor A Sobenin
- Institute of General Pathology and Pathophysiology, Russian Academy of Medical Sciences, 125315, Moscow, Russia
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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: 2.8] [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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Wang X, Liu X, Kishimoto C, Yuan Z. The role of Fcγ receptors in atherosclerosis. Exp Biol Med (Maywood) 2012; 237:609-16. [PMID: 22688821 DOI: 10.1258/ebm.2012.011373] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Atherosclerosis is widely considered to be an immune-mediated process. Fcγ receptors (Fcγ Rs) contribute to the regulation of a multitude of immune and inflammatory responses and are implicated in human atherosclerotic lesions. Major cell types involved in the pathogenesis of atherosclerosis express Fcγ Rs and their proatherogenic ligands such as immune complexes and C-reactive protein, which act to activate Fcγ R signaling pathways. This review summarizes recent significant progress addressing the multifaceted roles of Fcγ Rs in atherogenesis which comes from the studies of Fcγ R-deficient animal models, clinical investigations and in vitro molecular and cellular studies. These new findings help us appreciate the emerging role of Fcγ Rs in atherosclerosis, and suggest Fcγ Rs as a potential therapeutic target for atherosclerosis.
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Affiliation(s)
- Xinhong Wang
- Department of Cardiovascular Medicine, First Affiliated Hospital of Medical School, Xi'an Jiaotong University, 277 Yanta West Road, Xi'an, China
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Lopes-Virella MF, Baker NL, Hunt KJ, Lyons TJ, Jenkins AJ, Virella G. High concentrations of AGE-LDL and oxidized LDL in circulating immune complexes are associated with progression of retinopathy in type 1 diabetes. Diabetes Care 2012; 35:1333-40. [PMID: 22511260 PMCID: PMC3357232 DOI: 10.2337/dc11-2040] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To determine whether immunocomplexes (ICs) containing advanced glycation end product (AGE)-LDL (AGE-LDL) and oxidized LDL (oxLDL) contribute to the development of retinopathy over a 16-year period in subjects with type 1 diabetes. RESEARCH DESIGN AND METHODS Levels of AGE-LDL and oxLDL in ICs were measured in 517 patients of the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) cohort. Retinopathy was assessed by stereoscopic fundus photography. Cox proportional hazards models were used to assess the effect of AGE-LDL-ICs and oxLDL-ICs on retinopathy progression. RESULTS In unadjusted models, higher baseline levels of AGE-LDL-ICs and oxLDL-ICs significantly predicted progression of diabetic retinopathy outcomes. After adjustment by study-design variables (treatment group, retinopathy cohort, duration of type 1 diabetes, and baseline albumin excretion rate [AER], hemoglobin A(1c) (HbA(1c)), and Early Treatment Diabetic Retinopathy Study [ETDRS] score), one SD increase in IC levels was associated with 47% (hazard ratio [HR] 1.47 [95% CI 1.19-1.81]; AGE-LDL-IC) and 45% (1.45 [1.17-1.80]; oxLDL-IC) increased risk of developing proliferative diabetic retinopathy (PDR) and 37% (1.37 [1.12-1.66]; to both ICs) increased risk of progressing to severe nonproliferative retinopathy. Analyses were stratified by retinopathy cohort because results differed between primary and secondary cohorts. For AGE-LDL-ICs, HR for progression to PDR was 2.38 (95% CI 1.30-4.34) in the primary cohort and attenuated in the secondary cohort (1.29 [1.03-1.62]). Similar results were observed for oxLDL-ICs. CONCLUSIONS Increased levels of AGE-LDL and oxLDL in ICs are associated with increased risk for progression to advanced retinopathy in patients with type 1 diabetes, indicating that the antibody response to modified LDL plays a significant role in retinopathy progression.
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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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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: 1.2] [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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Wade NS, Major AS. The problem of accelerated atherosclerosis in systemic lupus erythematosus: insights into a complex co-morbidity. Thromb Haemost 2011; 106:849-57. [PMID: 21979131 DOI: 10.1160/th11-05-0330] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 09/06/2011] [Indexed: 02/06/2023]
Abstract
Rheumatic autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus (SLE), are associated with antibodies to "self" antigens. Persons with autoimmune diseases, most notably SLE, are at increased risk for developing accelerated cardiovascular disease. The link between immune and inflammatory responses in the pathogenesis of cardiovascular disease has been firmly established; yet, despite our increasing knowledge, accelerated atherosclerosis continues to be a significant co-morbidity and cause of mortality in SLE. Recent animal models have been generated in order to identify mechanism(s) behind SLE-accelerated atherosclerosis. In addition, clinical studies have been designed to examine potential treatments options. This review will highlight data from recent studies of immunity in SLE and atherosclerosis and discuss the potential implications of these investigations.
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Affiliation(s)
- N S Wade
- Department of Pathology,Vanderbilt University Medical Center, Nashville, TN 37232, USA
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Schneider MP, Leusen JHW, Herrmann M, Garlichs CD, Amann K, John S, Schmieder RE. The Fcγ receptor IIA R131H gene polymorphism is associated with endothelial function in patients with hypercholesterolaemia. Atherosclerosis 2011; 218:411-5. [PMID: 21813128 DOI: 10.1016/j.atherosclerosis.2011.07.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2011] [Revised: 05/29/2011] [Accepted: 07/05/2011] [Indexed: 10/17/2022]
Abstract
OBJECTIVE A gene polymorphism substituting arginine (R) for histidine (H) at position 131 has been described within the Fcγ receptor IIa (FcγRIIa). The R allele is associated with increased binding of CRP and enhanced activation of monocytes. FcγRIIa is also expressed on endothelial cells, and we hypothesized this polymorphism would be associated with alterations of endothelial function. METHODS Genomic DNA was extracted and allele-specific PCR reactions were used to determine the FcγRIIa H131R polymorphism in 78 hypercholesterolaemic subjects. Using strain gauge plethysmography, forearm blood flow (FBF) responses were determined to intra-arterial infusion of acetylcholine (ACH), for endothelium-dependent vasodilatation (EDV), to nitroprusside (NP), for endothelium-independent vasodilatation (EIV), to NG-monomethyl-l-arginine (l-NMMA), for basal NO activity, and to ACH in the presence of l-NMMA, to assess the contribution of NO release to EDV. RESULTS Homozygous carriers of the H allele (n=30) had significantly better EDV than homozygous carriers of the R allele (n=15), while heterozygotes showed an intermediate phenotype (n=33) (e.g. % increase of FBF to ACH 48μg/min: 527±359% in H/H versus 452±262% in H/R versus 332±413% in R/R, p=0.0012 by 2-way ANOVA). EIV and basal NO activity were not affected by genotype, and co-infusion of l-NMMA abolished the differences in EDV. CONCLUSIONS The R allele of the FcγRIIa polymorphism is associated with impaired EDV and reduced NO activity during endothelial cell stimulation. These data suggest that the functional effects of the FcγRIIa H131R gene polymorphism previously observed in vitro translate into clinically relevant alterations of endothelial function in vivo.
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Affiliation(s)
- Markus P Schneider
- Department of Nephrology and Hypertension, University of Erlangen-Nuremberg, Germany.
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Mera K, Nagai R, Takeo K, Izumi M, Maruyama T, Otagiri M. An autoantibody against Nε-(carboxyethyl)lysine (CEL): Possible involvement in the removal of CEL-modified proteins by macrophages. Biochem Biophys Res Commun 2011; 407:420-5. [DOI: 10.1016/j.bbrc.2011.03.040] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2011] [Accepted: 03/09/2011] [Indexed: 10/18/2022]
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Klein RL, Carter RE, Jenkins AJ, Lyons TJ, Baker NL, Gilbert GE, Virella G, Lopes-Virella MF, DCCT/EDIC Research Group. LDL-containing immune complexes in the DCCT/EDIC cohort: associations with lipoprotein subclasses. J Diabetes Complications 2011; 25:73-82. [PMID: 20605479 PMCID: PMC2978771 DOI: 10.1016/j.jdiacomp.2010.03.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 03/15/2010] [Accepted: 03/29/2010] [Indexed: 02/02/2023]
Abstract
Immune complexes containing modified LDL (LDL-IC) and NMR-determined Total LDL particle concentrations are significantly associated with intima-media thickness (IMT). We analyzed the associations between concentrations of NMR-determined lipoprotein subclasses and LDL-IC in the DCCT/EDIC cohort. LDL-IC concentrations in women and men of the DCCT/EDIC cohort did not differ significantly and were positively associated with Total LDL particle concentrations in men and women (r=0.34, r=0.32, respectively; P<.01) and with Small LDL concentration (r=0.22, r=0.13, respectively; P<.01). In women, Large LDL concentrations were also associated with LDL-IC (r=0.20, P<.01) while in men, the association was more modest (r=0.11, P<.05). Thus, both Small and Large LDL are associated with LDL-IC formation. Based on the results from statistical mediation analyses, we concluded that plasma concentrations of LDL-IC may provide a physiological link between the statistically significant association of Total LDL particle concentration with carotid artery IMT in subjects with Type 1 diabetes. Furthermore, after adjusting for conventional risk factors, there was a decrease in LDL-IC concentration even in the presence of high Total LDL particle concentrations in those women with high concentrations of Large HDL, but the association was not evident in men. This suggests that the associations between Large HDL and Total LDL particle concentrations, and their associations with LDL-IC levels, differ by gender and suggest that LDL-IC partially mediate the contribution of Total LDL particle concentration to increased carotid IMT in diabetic men.
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Affiliation(s)
- Richard L Klein
- Division of Endocrinology, Metabolism, and Medical Genetics, Department of Medicine, Medical University of South Carolina, Charleston, SC 29403, USA.
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Badr G, Bashandy S, Ebaid H, Mohany M, Sayed D. Vitamin C supplementation reconstitutes polyfunctional T cells in streptozotocin-induced diabetic rats. Eur J Nutr 2011; 51:623-33. [PMID: 21350934 DOI: 10.1007/s00394-011-0176-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Accepted: 01/17/2011] [Indexed: 02/08/2023]
Abstract
BACKGROUND Studies have demonstrated that vitamin C supplementation enhances the immune system, prevents DNA damage, and decreases the risk of a wide range of diseases. Other study reported that leukocyte vitamin C level was low in diabetic individuals compared with nondiabetic controls. AIM OF THE WORK To study the effect of vitamin C on oxidative stress, blood lipid profile, and T-cell responsiveness during streptozotocin (STZ)-induced type I diabetes mellitus. METHODS Thirty male Sprague-Dawley rats were randomly split into three groups. The first served as a control group (n = 10) in which rats were injected with the vehicle alone. The second (n = 10) and the third groups (n = 10) were rendered diabetic by intraperitoneal (i.p.) injection of single doses of STZ (60 mg/kg body weight). The third group was supplemented with vitamin C (100 mg/kg body weight) for 2 months. RESULTS T lymphocytes from the diabetic rats were found to be in a stunned state, with a decreased surface expression of the CD28 costimulatory molecule, low levels of phosphorylated AKT, altered actin polymerization, diminished proliferation and cytokine production, and, eventually, a marked decrease in abundance in the periphery. Vitamin C was found to significantly decrease the elevated levels of blood hydroperoxide, glucose, cholesterol, triglycerides and low-density lipoprotein (LDL) in diabetic rats. Furthermore, it was found to restore CD28 expression, AKT phosphorylation, actin polymerization, and polyfunctional T cells (IFN-γ- and IL-2-producing cells that exhibit a high proliferation capacity). CONCLUSION Vitamin C treatment restores and reconstitutes polyfunctional, long-lived T cells in diabetic rats.
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Affiliation(s)
- Gamal Badr
- Zoology Department, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia.
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Lopes-Virella MF, Baker NL, Hunt KJ, Lachin J, Nathan D, Virella G, DCCT/EDIC Research Group. Oxidized LDL immune complexes and coronary artery calcification in type 1 diabetes. Atherosclerosis 2011; 214:462-7. [PMID: 21156319 PMCID: PMC3031663 DOI: 10.1016/j.atherosclerosis.2010.11.012] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [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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Abstract
Atherosclerosis is now recognized as a chronic inflammatory disease and is characterized by features of inflammation at all stages of its development. It also appears to display elements of autoimmunity, and several autoantibodies including those directed against oxidized low-density lipoprotein (ox-LDL) and heat shock proteins (Hsps) have been identified in atherosclerosis. Immune complexes (ICs) may form between these antigens and autoantibodies and via Fc receptor signaling and complement activation may modulate the inflammation in atherosclerosis. Antibody isotype may direct the role that ICs play in atherogenesis, immunoglobulin G (IgG) being potentially pro-atherogenic and immunoglobulin M (IgM) playing a protective role. Therapeutic options targeting complement activation and those which are potentially Fc-receptor mediated have been investigated in animal models, though targeting Fc receptor signaling is an area that needs further investigation.
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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: 1.9] [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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Levitan I, Volkov S, Subbaiah PV. Oxidized LDL: diversity, patterns of recognition, and pathophysiology. Antioxid Redox Signal 2010; 13:39-75. [PMID: 19888833 PMCID: PMC2877120 DOI: 10.1089/ars.2009.2733] [Citation(s) in RCA: 328] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Revised: 10/09/2009] [Accepted: 11/02/2009] [Indexed: 02/06/2023]
Abstract
Oxidative modification of LDL is known to elicit an array of pro-atherogenic responses, but it is generally underappreciated that oxidized LDL (OxLDL) exists in multiple forms, characterized by different degrees of oxidation and different mixtures of bioactive components. The variable effects of OxLDL reported in the literature can be attributed in large part to the heterogeneous nature of the preparations employed. In this review, we first describe the various subclasses and molecular composition of OxLDL, including the variety of minimally modified LDL preparations. We then describe multiple receptors that recognize various species of OxLDL and discuss the mechanisms responsible for the recognition by specific receptors. Furthermore, we discuss the contentious issues such as the nature of OxLDL in vivo and the physiological oxidizing agents, whether oxidation of LDL is a prerequisite for atherogenesis, whether OxLDL is the major source of lipids in foam cells, whether in some cases it actually induces cholesterol depletion, and finally the Janus-like nature of OxLDL in having both pro- and anti-inflammatory effects. Lastly, we extend our review to discuss the role of LDL oxidation in diseases other than atherosclerosis, including diabetes mellitus, and several autoimmune diseases, such as lupus erythematosus, anti-phospholipid syndrome, and rheumatoid arthritis.
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Affiliation(s)
- Irena Levitan
- Section of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
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Feng X, Zhang Y, Xu R, Xie X, Tao L, Gao H, Gao Y, He Z, Wang H. Lipopolysaccharide up-regulates the expression of Fcα/μ receptor and promotes the binding of oxidized low-density lipoprotein and its IgM antibody complex to activated human macrophages. Atherosclerosis 2010; 208:396-405. [PMID: 19682689 DOI: 10.1016/j.atherosclerosis.2009.07.035] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2009] [Revised: 06/22/2009] [Accepted: 07/07/2009] [Indexed: 01/08/2023]
Affiliation(s)
- Xuyang Feng
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Changle West Road No. 17, Xi'an 710032, PR China
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Lopes-Virella MF, Virella G. Clinical significance of the humoral immune response to modified LDL. Clin Immunol 2010; 134:55-65. [PMID: 19427818 PMCID: PMC2808452 DOI: 10.1016/j.clim.2009.04.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [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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Mayadas TN, Tsokos GC, Tsuboi N. Mechanisms of immune complex-mediated neutrophil recruitment and tissue injury. Circulation 2009; 120:2012-24. [PMID: 19917895 DOI: 10.1161/circulationaha.108.771170] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Tanya N Mayadas
- Center for Excellence in Vascular Biology, Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, 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 PMCID: PMC2605965 DOI: 10.1016/j.atherosclerosis.2008.03.025] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [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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Abstract
Morphological and immunocytochemical studies have elucidated the complex processes involved in atherogenesis. The notion of plaque instability has emerged from this work and underscored the importance of inflammation in determining clinical complications associated with atherosclerosis, such as acute coronary syndrome. Cells of the immune system have been detected within atherosclerotic lesions and auto-antibodies directed against modified LDL and heat-shock proteins have been identified in the blood of individuals with atherosclerosis. The use of risk 'engines', e.g. the Framingham coronary risk score, has facilitated the identification of individuals at high risk, but the constituent classical risk factors used in these algorithms do not adequately differentiate individuals at moderate risk. As age is a major component of the equations used in these algorithms they are not particularly useful in young adults, and their applicability to non-Caucasian populations has been questioned. Biomarkers of early disease and plaque instability have therefore both been sought. Although some of these markers have been shown individually to be associated with a significant hazard ratio, no substantial improvement in discrimination has been demonstrated when they are incorporated into a risk 'engine'. The latter has generally been assessed by receiver operator characteristic curve analysis, although this approach has been criticised. Other modalities, including imaging and functional assessments of vascular function, are now being developed for clinical use.
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Leon C, Jia J, Qiu G, Hill JS, Wasan KM. Modifications in low-density lipoprotein receptor expression affects Cyclosporin A cellular uptake and cytotoxicity. J Pharm Sci 2008; 97:2350-61. [PMID: 17823952 DOI: 10.1002/jps.21141] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The purpose of this study was to test the effect of modulating the expression of the human low-density lipoprotein receptor (LDLr) in human embryonic kidney (293T) cells on Cyclosporin A (CsA) cellular uptake and CsA-mediated cytotoxicity. LDLr expression was modulated using RNA interference (RNAi) and an LDLr overexpression plasmid. One of the small-interfering RNA (siRNA) constructs, LDLr-792, showed a 60% decrease in LDLr protein expression. The downregulation effect was specific as transfection with an annexin V (AxV) siRNA construct did not decrease LDLr expression levels. AxV and ABCA1 expression levels were not affected in the cells transfected with LDLr-792 (LDLr(LOW) cells) compared to the controls. At a functional level, fluorescent low-density lipoprotein (LDL) (DiI-LDL) internalization in the LDLr(LOW) cells was decreased (30%) compared to control cells. We tested the dose-dependent cytotoxicity induced by CsA using a respiration assay. We found a decrease in CsA-mediated cytotoxicity in the range of CsA doses studied (1-10 microg/mL) in the LDLr(LOW) cells compared to the pSHAG-transfected cells, reaching a statistical significance at 10 microg/mL CsA. At higher CsA doses we found a significant decrease in LDLr expression. When the control and LDLr(LOW) cells were treated with another cytotoxic drug, gentamycin, there was no difference in the cell viability, suggesting that this effect is specific for CsA. We confirmed the association of LDLr expression levels with CsA uptake by overexpressing the LDLr. The LDLr overexpressing cells showed an enhanced uptake of radiolabelled CsA. Taken together these results suggest that CsA internalization and cytotoxicity are affected by the LDL receptor expression levels.
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Affiliation(s)
- Carlos Leon
- Division of Pharmaceutics and Biopharmaceutics, Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver British Columbia, Canada V6T 1Z3
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Andican G, Seven A, Uncu M, Cantaşdemir M, Numan F, Burçak G. Oxidized LDL and anti-oxLDL antibody levels in peripheral atherosclerotic disease. Scand J Clin Lab Invest 2008; 68:473-478. [PMID: 18609113 DOI: 10.1080/00365510701842996] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
OBJECTIVE Oxidative modification of LDL (oxLDL) is important in atherogenesis and is proposed as a useful marker for identifying patients with coronary artery disease. Antibody to oxLDL (oxLDL Ab) is detected in human sera, although its biological significance is not well established. We aimed to measure oxLDL and oxLDL Ab in peripheral atherosclerotic disease (PAD) patients, and to examine the relation between them in an attempt to understand the role of oxLDL Ab. Total risk of atherosclerosis was estimated using the global risk assessment score (GRAS) calculated on the basis of age, total cholesterol, HDL cholesterol (HDL-Chol), diabetes, hypertension and smoking. MATERIAL AND METHODS Twenty-one patients aged 63.05+/-9.13 years, diagnosed by peripheric angiography as PAD, and 21 healthy controls aged 47.67+/-13.61 years took part in the study. Total LDL and HDL cholesterol levels were determined by enzymatic methods. Levels of circulating oxLDL were measured by monoclonal antibody 4E6-based competition ELISA. IgG class oxLDL Ab titre was measured by ELISA. RESULTS Compared to healthy controls, PAD patients had higher levels of oxLDL (p<0.05), oxLDL Ab (p<0.05), LDL cholesterol (LDL-Chol) (p<0.05), total cholesterol (p<0.05) and lower HDL-Chol (p<0.05). OxLDL was found to be positively correlated with total cholesterol (r = 0.471, p<0.05) and LDL-Chol (r = 0.614, p<0.01) and GRAS (r = 0.435, p<0.05) and negatively with HDL-Chol (r = -0.459, p<0.05), but not with oxLDL Ab in PAD patients. CONCLUSIONS These findings might indicate that high LDL-Chol levels influence the oxidation of LDL and that oxLDL is a possible marker of PAD. However, the role of oxLDL Ab in atherosclerosis remains controversial.
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Affiliation(s)
- Gülnur Andican
- Department of Biochemistry, Cerrahpaşa Medical Faculty, Istanbul University, Istanbul, Turkey.
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Chen HW, Kuo CL, Huang CS, Kuo SJ, Liu CS. Oxidized Low-Density Lipoproteins, Autoantibodies against Oxidized Low-Density Lipoproteins and Carotid Intima Media Thickness in a Clinically Healthy Population. Cardiology 2007; 110:252-9. [DOI: 10.1159/000112409] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2007] [Accepted: 08/05/2007] [Indexed: 01/21/2023]
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46
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Westerweel PE, Luyten RKMAC, Koomans HA, Derksen RHWM, Verhaar MC. Premature atherosclerotic cardiovascular disease in systemic lupus erythematosus. ACTA ACUST UNITED AC 2007; 56:1384-96. [PMID: 17469095 DOI: 10.1002/art.22568] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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47
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Nagarajan S. Anti-OxLDL IgG blocks OxLDL interaction with CD36, but promotes FcgammaR, CD32A-dependent inflammatory cell adhesion. Immunol Lett 2006; 108:52-61. [PMID: 17081622 DOI: 10.1016/j.imlet.2006.09.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Revised: 09/26/2006] [Accepted: 09/26/2006] [Indexed: 11/16/2022]
Abstract
Generation of antibodies against oxidized-low-density lipoproteins (oxLDL) during atherosclerosis could result in the formation and deposition of oxLDL immune complexes (oxLDL-IC) on the vascular endothelial cells. Inflammatory cells express scavenger receptor (SR such as CD36) and Fcgamma receptor (FcgammaR: CD32A and CD64) that can bind to oxLDL and oxLDL-IC, respectively. Hence, depending on anti-oxLDL IgG titer, circulating monocytes could adhere to endothelium to oxLDL-IC-coated vascular bed via either FcgammaR and/or CD36. In this study, we determined the relative contribution of SR and FcgammaR in mediating monocyte interaction with oxLDL-IC deposited on vascular bed. At saturating levels of anti-oxLDL IgG concentration, monocytic cells adhered to oxLDL-IC and this adhesion is completely blocked by anti-CD32A mAb. Using CHOK1-CD32A-CD36 cells expressing equal levels of CD32A and CD36, it was observed that at lower concentrations of anti-oxLDL IgG, CD32A and CD36 contribute about 75% and 25% of cell adhesion, respectively, while at higher concentrations of anti-oxLDL IgG the adhesion is completely CD32A-dependent. CD32A-dependent adhesion was further confirmed with peripheral blood monocytes and platelets that express 2- to 5-fold higher levels of CD36 compared to CD32A. Further, PBMC adhesion to oxLDL-IC-deposited endothelial cells induced secretion of pro-inflammatory chemokines, MCP-1 and IL-8. Our results demonstrate that anti-oxLDL IgG blocks oxLDL interaction with SR such as CD36, whereas oxLDL-IC formation promotes monocyte adhesion and subsequent chemokine release through FcgammaR. These findings suggest a role for FcgammaR-mediated inflammatory cell activation in the progression of atherosclerosis.
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Affiliation(s)
- Shanmugam Nagarajan
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Arkansas Children's Nutrition Center, RM N2021C, 1120 Marshall Street, Little Rock, AR 72202, USA.
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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: 91] [Impact Index Per Article: 4.8] [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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Oksjoki R, Kovanen PT, Lindstedt KA, Jansson B, Pentikäinen MO. OxLDL–IgG Immune Complexes Induce Survival of Human Monocytes. Arterioscler Thromb Vasc Biol 2006; 26:576-83. [PMID: 16373614 DOI: 10.1161/01.atv.0000201041.14438.8d] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Immune complexes containing oxidatively modified low-density lipoprotein (oxLDL) particles are deposited in human atherosclerotic lesions during atherogenesis. Here we studied whether OxLDL-IgG immune complexes (OxLDL-IgG ICs) affect survival of human monocytes. METHODS AND RESULTS As demonstrated by light microscopy, and analysis of cell proliferation, caspase-3 activity, and DNA fragmentation, OxLDL-IgG ICs promoted survival of cultured human monocytes by decreasing their spontaneous apoptosis. OxLDL-IgG ICs induced a concentration-dependent production of the major monocyte growth factor, monocyte colony-stimulating factor (M-CSF), by the monocytes, but its inhibition was without effect on OxLDL-IgG IC-induced monocyte survival. Rather, OxLDL-IgG ICs induced rapid phosphorylation of Akt, suggesting a direct anti-apoptotic effect mediated by cross-linking of Fcgamma receptors. Experiments with receptor blocking antibodies revealed that the OxLDL-IgG IC-induced monocyte survival was mediated by Fcgamma receptor I. CONCLUSIONS The results show that OxLDL-IgG ICs promote survival of monocytes by cross-linking Fcgamma receptor I and activating Akt-dependent survival signaling. The results reveal a novel mechanism by which an immune reaction toward oxLDL can play a role in the accumulation of macrophages in human atherosclerotic lesions.
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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: 36] [Impact Index Per Article: 1.9] [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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