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Elyasi A, Voloshyna I, Ahmed S, Kasselman LJ, Behbodikhah J, De Leon J, Reiss AB. The role of interferon-γ in cardiovascular disease: an update. Inflamm Res 2020; 69:975-988. [PMID: 32699989 DOI: 10.1007/s00011-020-01382-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 07/09/2020] [Accepted: 07/13/2020] [Indexed: 12/17/2022] Open
Abstract
PURPOSE Cardiovascular disease (CVD) is the leading cause of death, globally, and its prevalence is only expected to rise due to the increasing incidence of co-morbidities such as obesity and diabetes. Medical treatment of CVD is directed primarily at slowing or reversing the underlying atherosclerotic process by managing circulating lipids with an emphasis on control of low-density lipoprotein (LDL) cholesterol. However, over the past several decades, there has been increasing recognition that chronic inflammation and immune system activation are important contributors to atherosclerosis. This shift in focus has led to the elucidation of the complex interplay between cholesterol and cellular secretion of cytokines involved in CVD pathogenesis. Of the vast array of cytokine promoting atherosclerosis, interferon (IFN)-γ is highly implicated and, therefore, of great interest. METHODS Literature review was performed to further understand the effect of IFN-γ on the development of atherosclerotic CVD. RESULTS IFN-γ, the sole member of the type II IFN family, is produced by T cells and macrophages, and has been found to induce production of other cytokines and to have multiple effects on all stages of atherogenesis. IFN-γ activates a variety of signaling pathways, most commonly the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway, to induce oxidative stress, promote foam cell accumulation, stimulate smooth muscle cell proliferation and migration into the arterial intima, enhance platelet-derived growth factor expression, and destabilize plaque. These are just a few of the contributions of IFN-γ to the initiation and progression of atherosclerotic CVD. CONCLUSION Given the pivotal role of IFN-γ in the advancement of CVD, activation of its signaling pathways is being explored as a driver of atherosclerosis. Manipulation of this key cytokine may lead to novel therapeutic avenues for CVD prevention and treatment. A number of therapies are being explored with IFN-γ as the potential target.
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Affiliation(s)
- Ailin Elyasi
- Department of Medicine and Biomedical Research Institute, NYU Long Island School of Medicine, NYU Winthrop Hospital, 101 Mineola Boulevard, Suite 4-004, Mineola, NY, 11501, USA
| | - Iryna Voloshyna
- Department of Medicine and Biomedical Research Institute, NYU Long Island School of Medicine, NYU Winthrop Hospital, 101 Mineola Boulevard, Suite 4-004, Mineola, NY, 11501, USA
| | - Saba Ahmed
- Department of Medicine and Biomedical Research Institute, NYU Long Island School of Medicine, NYU Winthrop Hospital, 101 Mineola Boulevard, Suite 4-004, Mineola, NY, 11501, USA
| | - Lora J Kasselman
- Department of Medicine and Biomedical Research Institute, NYU Long Island School of Medicine, NYU Winthrop Hospital, 101 Mineola Boulevard, Suite 4-004, Mineola, NY, 11501, USA
| | - Jennifer Behbodikhah
- Department of Medicine and Biomedical Research Institute, NYU Long Island School of Medicine, NYU Winthrop Hospital, 101 Mineola Boulevard, Suite 4-004, Mineola, NY, 11501, USA
| | - Joshua De Leon
- Department of Medicine and Biomedical Research Institute, NYU Long Island School of Medicine, NYU Winthrop Hospital, 101 Mineola Boulevard, Suite 4-004, Mineola, NY, 11501, USA
| | - Allison B Reiss
- Department of Medicine and Biomedical Research Institute, NYU Long Island School of Medicine, NYU Winthrop Hospital, 101 Mineola Boulevard, Suite 4-004, Mineola, NY, 11501, USA.
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Kzhyshkowska J, Neyen C, Gordon S. Role of macrophage scavenger receptors in atherosclerosis. Immunobiology 2012; 217:492-502. [PMID: 22437077 DOI: 10.1016/j.imbio.2012.02.015] [Citation(s) in RCA: 172] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2012] [Accepted: 02/19/2012] [Indexed: 12/22/2022]
Abstract
Accumulating evidence indicates that atherosclerosis is a chronic inflammatory disease. The key innate immune cells that are involved in the pathogenesis of atherosclerosis are circulating monocytes and plaque macrophages. Complex interplay between immune and metabolic processes results in pathological activity of these cells. The best understood pathological process mediated by macrophages is their inability to process modified lipoproteins properly resulting in the formation of foamy cells, which are a dangerous component of atherosclerotic plaques. Key molecules involved in the recognition and processing of modified lipoproteins are scavenger receptors (SR). This is a large family of surface expressed structurally heterogeneous receptors with a broad spectrum of endogenous and exogenous ligands. The common functional feature of SR is internalisation of extracellular components and targeting them for lysosomal degradation. However, these relatively simple functions can have complex consequences, since they are linked to diverse specific signalling pathways and to other membrane transport pathways. Moreover, scavenger receptors can co-operate with other types of receptors increasing the variability of the macrophage response to multiple extracellular ligands. At least some SRs respond to modified lipoproteins by amplification of inflammation and accumulation of macrophages in the plaque, while some SRs may support tolerogenic reactions. Outcome of different SR activities will be the decision of monocytes and macrophage to guard homeostatic balance, support atherosclerosis progression and plaque instability by inflammatory reactions, or support rapid fibrotic processes in the plaque that stabilise it. Despite the accumulating knowledge about the molecular mechanisms of scavenger receptor action, their role in the progression of atherosclerosis remains controversial. The activities of scavenger receptors that can contribute to each of these processes are a subject of current review.
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Affiliation(s)
- Julia Kzhyshkowska
- Department of Dermatology, Medical Faculty Mannheim, Ruprecht-Karls University of Heidelberg, Germany.
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3
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Dillard A, Matthan NR, Lichtenstein AH. Tamm-Horsfall protein 1 macrophage lipid accumulation unaffected by fatty acid double-bond geometric or positional configuration. Nutr Res 2012; 31:625-30. [PMID: 21925348 DOI: 10.1016/j.nutres.2011.08.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Revised: 07/29/2011] [Accepted: 08/02/2011] [Indexed: 12/16/2022]
Abstract
Dietary fatty acid type alters atherosclerotic lesion progression and macrophage lipid accumulation. Incompletely elucidated are the mechanisms by which fatty acids differing in double-bond geometric or positional configuration alter arterial lipid accumulation. The objective of this study was to evaluate the suitability of using Tamm-Horsfall protein 1 (THP-1) macrophages as a model for human monocytes/macrophages to address this issue. Our hypothesis was that THP-1 macrophages pretreated with ω-3 polyunsaturated fatty acids (PUFA) or fatty acid containing a cis double bond would accumulate less lipid, particularly cholesteryl ester, compared with ω-6 polyunsaturated fatty acids or a fatty acid containing a trans double bond, respectively. THP-1 monocytes were differentiated into macrophages and then incubated with fatty acids for 48 hours. There was an increase in intracellular lipid in response to all the fatty acids assessed, and by response was similar among the fatty acids. The increase in lipid accumulation was contributed to triglyceride and to a lesser extent cholesterol, primarily free cholesterol. These data suggest that free fatty acids bound to bovine serum albumin, regardless of double-bond geometric or positional configuration, induce triglyceride accumulation but had only a modest effect on cholesterol accumulation in THP-1 macrophages. The cells appeared to respond similarly to the assessed fatty acids in terms of amount and type of lipid accumulated. Hence, the THP-1 cell line was not appropriate to test the hypotheses of interest.
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Affiliation(s)
- Alice Dillard
- Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA.
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Linking immunity to atherosclerosis: implications for vascular pharmacology--a tribute to Göran K. Hansson. Vascul Pharmacol 2011; 56:29-33. [PMID: 22120836 DOI: 10.1016/j.vph.2011.11.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 11/10/2011] [Accepted: 11/11/2011] [Indexed: 12/26/2022]
Abstract
For the past decade, we have deepened our understanding of the pathogenesis of atherosclerosis, a chronic arterial disease that causes cardiac and cerebral infarction and peripheral vascular disorders. Because of this extended understanding, more effective strategies for prevention and treatment of this disease are emerging. One of the fundamental mechanisms that lead to progress or regression in atherosclerosis, thus influencing its life-threatening complications, occurs through functional changes in vascular immunity and inflammation. This review briefly summarizes the discoveries in basic and translational sciences in this area and recent advances in clinical medicine against atherosclerotic vascular diseases.
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Wolfs IMJ, Donners MMPC, de Winther MPJ. Differentiation factors and cytokines in the atherosclerotic plaque micro-environment as a trigger for macrophage polarisation. Thromb Haemost 2011; 106:763-71. [PMID: 21947328 DOI: 10.1160/th11-05-0320] [Citation(s) in RCA: 144] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Accepted: 08/23/2011] [Indexed: 12/13/2022]
Abstract
The phenotype of macrophages in atherosclerotic lesions can vary dramatically, from a large lipid laden foam cell to a small inflammatory cell. Classically, the concept of macrophage heterogeneity discriminates between two extremes called either pro-inflammatory M1 macrophages or anti-inflammatory M2 macrophages. Polarisation of plaque macrophages is predominantly determined by the local micro-environment present in the atherosclerotic lesion and is rather more complex than typically described by the M1/M2 paradigm. In this review we will discuss the role of various polarising factors in regulating the phenotypical state of plaque macrophages. We will focus on two main levels of phenotype regulation, one determined by differentiation factors produced in the lesion and the other determined by T-cell-derived polarising cytokines. With foam cell formation being a key characteristic of macrophages during atherosclerosis initiation and progression, these polarisation factors will also be linked to lipid handling of macrophages.
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Affiliation(s)
- I M J Wolfs
- Dept. of Molecular Genetics, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
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6
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Chen SC, Lin YL, Huang B, Wang DL, Cheng JJ. Salvianolic acid B suppresses IFN-γ-induced JAK/STAT1 activation in endothelial cells. Thromb Res 2011; 128:560-4. [PMID: 21992896 DOI: 10.1016/j.thromres.2011.08.032] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 06/30/2011] [Accepted: 08/08/2011] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Dysfunction of the endothelium contributes to pathological conditions of the arterial wall including atherosclerosis as a result of immunological and/or inflammatory responses. Salvianolic acid B (Sal B), a pure and active compound extracted from the Chinese herb Salvia miltiorrhizae (SM) was characterized for its anti-inflammatory and anti-oxidant properties on vascular system. METHODS AND RESULTS Sal B pretreatment significantly inhibited the IFN-γ-induced phosphorylations of JAK2 (Tyr 1007/1008) and STAT1 (Tyr701 and Ser727). Consistently, IFN-γ-induced STAT1 downstream targets CXC chemokines' IP-10, Mig, and I-TAC were suppressed by Sal B pretreatment. Sal B inhibited promoter activities of IP-10 and the secretion of IP-10 protein. The monocyte adhesion to IFN-γ-treated ECs was observed to be reduced after Sal B pretreatment. ECs treated with Sal B alone also increased the expression of PIAS1 and SOCS1 which may also contribute to its inhibitory effect on JAK-STAT1 signaling pathways. CONCLUSIONS The anti-inflammatory properties of Sal B on IFN-γ-induced JAK-STAT1 activation were demonstrated in the present study which provides a molecular basis for possible therapeutic usage on vascular disorders.
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Affiliation(s)
- Shih Chung Chen
- Department of Cardiology, New Taipei City Hospital, New Taipei City, Taiwan
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7
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Dual use of amphiphilic macromolecules as cholesterol efflux triggers and inhibitors of macrophage athero-inflammation. Biomaterials 2011; 32:8319-27. [PMID: 21816466 DOI: 10.1016/j.biomaterials.2011.07.039] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 07/13/2011] [Indexed: 11/23/2022]
Abstract
Activated vascular wall macrophages can rapidly internalize modified lipoproteins and escalate the growth of atherosclerotic plaques. This article proposes a biomaterials-based therapeutic intervention for depletion of non-regulated cholesterol accumulation and inhibition of inflammation of macrophages. Macromolecules with high scavenger receptor (SR)-binding activity were investigated for SR-mediated delivery of agonists to cholesterol-trafficking nuclear liver-X receptors. From a diverse feature space of a family of amphiphilic macromolecules of linear and aromatic mucic acid backbones modified with varied aliphatic chains and conjugated with differentially branched poly(ethylene glycol), a key molecule (carboxyl-terminated, C12-derivatized, linear mucic acid backbone) was selected for its ability to preferentially bind scavenger receptor A (SR-A) as the key target. At a basal level, this macromolecule suppressed the pro-inflammatory signaling of activated THP-1 macrophages while competitively lowering oxLDL uptake in vitro through scavenger receptor SRA-1 targeting. To further deplete intracellular cholesterol, the core macromolecule structure was exploited to solubilize a hydrophobic small molecule agonist for nuclear Liver-X Receptors, which regulate the efflux of intracellular cholesterol. The macromolecule-encapsulated agonist system was found to reduce oxLDL accumulation by 88% in vitro in comparison to controls. in vivo studies were designed to release the macromolecules (with or without encapsulated agonist) to injured carotid arteries within Sprague Dawley rats fed a high fat diet, conditions that yield enhanced cholesterol accumulation and macrophage recruitment. The macromolecules lowered intimal levels of accumulated cholesterol (50% for macromolecule alone; 70% for macromolecule-encapsulated agonist) and inhibited macrophage retention (92% for macromolecule; 96% for macromolecule-encapsulated agonist; 4 days) relative to non-treated controls. Thus, this study highlights the promise of designing bioactive macromolecule therapeutics based on scavenger receptor targeting, for potential management of vascular arterial disease.
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8
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Scavenger receptors as regulators of natural antibody responses and B cell activation in autoimmunity. Mol Immunol 2011; 48:1307-18. [DOI: 10.1016/j.molimm.2011.01.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2010] [Revised: 01/05/2011] [Accepted: 01/17/2011] [Indexed: 12/12/2022]
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Upadhya S, Mooteri S, Pai R. Role of interleukins in atherogenesis. Int J Angiol 2011. [DOI: 10.1007/bf01637039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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10
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Li F, Tian F, Wang L, Williamson IK, Sharifi BG, Shah PK. Pleiotrophin (PTN) is expressed in vascularized human atherosclerotic plaques: IFN-{gamma}/JAK/STAT1 signaling is critical for the expression of PTN in macrophages. FASEB J 2010; 24:810-22. [PMID: 19917672 PMCID: PMC2830133 DOI: 10.1096/fj.09-140780] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Accepted: 10/15/2009] [Indexed: 02/02/2023]
Abstract
Neovascularization is critical to destabilization of atheroma. We previously reported that the angiogenic growth factor pleiotrophin (PTN) coaxes monocytes to assume the phenotype of functional endothelial cells in vitro and in vivo. In this study we show that PTN expression is colocalized with capillaries of human atherosclerotic plaques. Among the various reagents that are critical to the pathogenesis of atherosclerosis, interferon (IFN)-gamma was found to markedly induce PTN mRNA expression in a dose-dependent manner in macrophages. Mechanistic studies revealed that the Janus kinase inhibitors, WHI-P154 and ATA, efficiently blocked STAT1 phosphorylation in a concentration- and time-dependent manner. Notably, the level of phosphorylated STAT1 was found to correlate directly with the PTN mRNA levels. In addition, STAT1/STAT3/p44/42 signaling molecules were found to be phosphorylated by IFN-gamma in macrophages, and they were translocated into the nucleus. Further, PTN promoter analysis showed that a gamma-activated sequence (GAS) located at -2086 to -2078 bp is essential for IFN-gamma-regulated promoter activity. Moreover, electrophoretic mobility shift, supershift, and chromatin immunoprecipitation analyses revealed that both STAT1 and STAT3 bind to the GAS at the chromatin level in the IFN-gamma stimulated cells. Finally, to test whether the combined effect of STAT1/STAT3/p44/42 signaling is required for the expression of PTN in macrophages, gene knockdowns of these transcription factors were performed using siRNA. Cells lacking STAT1, but not STAT3 or p42, have markedly reduced PTN mRNA levels. These data suggest that PTN expression in the human plaques may be in part regulated by IFN-gamma and that PTN is involved in the adaptive immunity.-Li, F., Tian, F., Wang, L., Williamson, I. K., Sharifi, B. G., Shah, P. K. Pleiotrophin (PTN) is expressed in vascularized human atherosclerotic plaques: IFN-gamma/JAK/STAT1 signaling is critical for the expression of PTN in macrophages.
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Affiliation(s)
- Fuqiang Li
- Cedars-Sinai Medical Center, Davis Bldg. 1016, 8700 Beverly Blvd., Los Angeles, CA 90048, USA
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11
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Takayama H, Nonomura N, Nishimura K, Oka D, Shiba M, Nakai Y, Nakayama M, Tsujimura A, Aozasa K, Okuyama A. Decreased immunostaining for macrophage scavenger receptor is associated with poor prognosis of prostate cancer. BJU Int 2008; 103:470-4. [PMID: 18778349 DOI: 10.1111/j.1464-410x.2008.08013.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
OBJECTIVE The aim of this study is to evaluate the expression of the macrophage scavenger receptor (MSR) in prostate needle biopsy specimens as a possible prognostic factor for prostate cancer. As MSR reportedly has a role in recognizing foreign pathogenic substances, MSR-positive inflammatory cells are often detected in solid tumours, and there is a correlation between the relative risk of prostate cancer and polymorphism of the MSR gene. PATIENTS AND METHODS MSR was evaluated by immunostaining in needle biopsies of the prostate from 135 patients who were confirmed to have prostate cancer. Among these men, 70 were treated by radical prostatectomy or by radiotherapy as definitive therapy; the other 65 were treated by hormonal therapy because of advanced disease or age. Needle-biopsy specimens were sectioned at 5 microm and immunostained with a monoclonal antibody against MSR. Six microscopic (x400) fields around the cancer foci were selected in each case for analysis. RESULTS The median number of MSR-positive cells (MSR count) in each case was 24. There was an inverse correlation between the MSR count and Gleason score and clinical stage. The MSR count was lower in patients with biochemical (prostate-specific antigen, PSA) failure than that in those with no PSA failure (P < 0.001). In all patients, the recurrence-free survival (RFS) rate was significantly higher in those with a high MSR count (> or =24) than that in those with low MSR count (<24, P < 0.001). Moreover, for patients treated by definitive or hormonal therapy, the RFS rates in those with a higher MSR count were higher than in those with a lower MSR count (P < 0.001 and 0.014, respectively). Cox multivariate analysis showed that the MSR count was a prognostic factor for prostate cancer in addition to extraprostatic extension and Gleason score (P = 0.002, 0.038 and 0.011, respectively). CONCLUSION The results of immunostaining of MSR in needle-biopsy specimens is a prognostic factor for prostate cancer.
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Affiliation(s)
- Hitoshi Takayama
- Department of Urology, Osaka University Graduate School of Medicine, Osaka, Japan
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12
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Heeneman S, Donners MMPC, Bai L, Daemen MJAP. Drug-induced immunomodulation to affect the development and progression of atherosclerosis: a new opportunity? Expert Rev Cardiovasc Ther 2007; 5:345-64. [PMID: 17338677 DOI: 10.1586/14779072.5.2.345] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Inflammation and cytokine pathways are crucial for the development and progression of atherosclerotic lesions. In this review, the hypothesis that immunomodulatory drugs provide a possible therapeutic modality for cardiovascular disease is evaluated. Therefore, after a short overview of the specific inflammatory pathways involved in atherosclerosis, literature on the effect of several immunomodulatory drugs, such as nonsteroidal anti-inflammatory drugs, specific cyclooxygenase inhibitors and immunosuppressive drugs, used currently in the prevention of rejection after organ transplant, on the development and progression of atherosclerosis is reviewed. In addition, the pleiotropic immunomodulatory effect of two established cardiovascular drugs (angiotensin-converting enzyme inhibitors and statins) is discussed.
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Affiliation(s)
- Sylvia Heeneman
- University of Maastricht, Department of Pathology, Cardiovascular Research Institute Maastricht, PO Box 5800, 6202 AZ Maastricht, The Netherlands.
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Abstract
This review article discusses the historical origin of our continuously evolving model of the etiology of atherosclerotic cardiovascular disease. The basic molecular biologic concepts underlying the development of coronary artery disease and the dynamic connection between the immune system and arterial integrity are explored. Emphasis is placed on the role of inflammation as a driving force in the process of atherosclerosis and vascular endothelium as a modulating factor in the pathogenesis of coronary artery disease.
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Affiliation(s)
- Allison B Reiss
- Vascular Biology Institute, Winthrop University Hospital, 222 Station Plaza, North, Suite 511-A, Mineola, NY 11501, USA.
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Knowles HJ, te Poele RH, Te Poole R, Workman P, Harris AL. Niacin induces PPARgamma expression and transcriptional activation in macrophages via HM74 and HM74a-mediated induction of prostaglandin synthesis pathways. Biochem Pharmacol 2006; 71:646-56. [PMID: 16386710 DOI: 10.1016/j.bcp.2005.11.019] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2005] [Revised: 11/21/2005] [Accepted: 11/22/2005] [Indexed: 01/11/2023]
Abstract
HM74 and HM74a have been identified as receptors for niacin. HM74a mediates the pharmacological anti-lipolytic effects of niacin in adipocytes by reducing intracellular cyclic AMP (cAMP) and inhibiting release of free fatty acids into the circulation. In macrophages, niacin induces peroxisome proliferator-activated receptor gamma (PPARgamma)-dependent and cAMP-dependent expression of genes mediating reverse cholesterol transport, although via an unidentified receptor. We describe constitutive expression of HM74a mRNA and hypoxia- and IFNgamma-inducible expression of HM74 and HM74a in human monocytic cell lines and primary cells in culture. In U937 cells niacin-induced expression of 15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)), the most potent endogenous ligand of PPARgamma. Both niacin and the structurally distinct HM74/HM74a ligand acifran-induced nuclear expression of PPARgamma protein and enhanced PPARgamma transcriptional activity. Niacin-induced PPARgamma transcriptional activity was pertussis toxin sensitive and required activity of phospholipase A(2) (EC 3.1.1.4), cyclo-oxygenase (EC 1.14.99.1) and prostaglandin D(2) synthase (EC 5.3.99.2). Niacin also induced PPARgamma transcriptional activity in HM74 and HM74a CHO cell transfectants, although not in vector-only control cells. This was sensitive to pertussis toxin and to inhibition of phoshoplipase A(2) and cyclo-oxygenase activity. Additionally, niacin increased intracellular cAMP in U937 via a pertussis toxin and cyclo-oxygenase-sensitive mechanism. These results indicate that HM74 and HM74a can mediate macrophage responses to niacin via activation of the prostaglandin synthesis pathway and induction and activation of PPARgamma. This suggests a novel mechanism(s) mediating the clinical effects of pharmacological doses of niacin.
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Affiliation(s)
- Helen J Knowles
- Cancer Research UK Molecular Oncology Laboratory, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford OX3 9DS, UK
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15
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Abstract
Reverse cholesterol transport (RCT) is a pathway by which accumulated cholesterol is transported from the vessel wall to the liver for excretion, thus preventing atherosclerosis. Major constituents of RCT include acceptors such as high-density lipoprotein (HDL) and apolipoprotein A-I (apoA-I), and enzymes such as lecithin:cholesterol acyltransferase (LCAT), phospholipid transfer protein (PLTP), hepatic lipase (HL) and cholesterol ester transfer protein (CETP). A critical part of RCT is cholesterol efflux, in which accumulated cholesterol is removed from macrophages in the subintima of the vessel wall by ATP-binding membrane cassette transporter A1 (ABCA1) or by other mechanisms, including passive diffusion, scavenger receptor B1 (SR-B1), caveolins and sterol 27-hydroxylase, and collected by HDL and apoA-I. Esterified cholesterol in the HDL is then delivered to the liver for excretion. In patients with mutated ABCA1 genes, RCT and cholesterol efflux are impaired and atherosclerosis is increased. In studies with transgenic mice, disruption of ABCA1 genes can induce atherosclerosis. Levels of HDL are inversely correlated with incidences of cardiovascular disease. Supplementation with HDL or apoA-I can reverse atherosclerosis by accelerating RCT and cholesterol efflux. On the other hand, pro-inflammatory factors such as interferon-gamma (IFN-gamma), endotoxin, tumour necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1beta), can be atherogenic by impairing RCT and cholesterol efflux, according to in vitro studies. RCT and cholesterol efflux play a major role in anti-atherogenesis, and modification of these processes may provide new therapeutic approaches to cardiovascular disease. Further research on new modifying factors for RCT and cholesterol efflux is warranted.
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Affiliation(s)
- R Ohashi
- Molecular Surgeon Research Center, Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston 77030, USA
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16
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Abstract
The role of cytokines in the pathogenesis of cardiovascular disease is increasingly evident since the identification of immune/inflammatory mechanisms in atherosclerosis and heart failure. In this review, we describe how innate and adaptive immune cascades trigger the release of cytokines and chemokines, resulting in the initiation and progression of atherosclerosis. We discuss how cytokines have direct and indirect effects on myocardial function. These include myocardial depressant effects of nitric oxide (NO) synthase-generated NO, as well as the biochemical effects of cytokine-stimulated arachidonic acid metabolites on cardiomyocytes. Cytokine influences on myocardial function are time-, concentration-, and subtype-specific. We provide a comprehensive review of these cytokine-mediated immune and inflammatory cascades implicated in the most common forms of cardiovascular disease.
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Affiliation(s)
- Vishal C Mehra
- Section of Cardiovascular Medicine, Yale University School of Medicine, New Haven, CT 06510, USA
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Alfaro Leon ML, Evans GF, Farmen MW, Zuckerman SH. Post-transcriptional regulation of macrophage ABCA1, an early response gene to IFN-γ. Biochem Biophys Res Commun 2005; 333:596-602. [PMID: 15946645 DOI: 10.1016/j.bbrc.2005.05.112] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Accepted: 05/23/2005] [Indexed: 10/25/2022]
Abstract
Interferon-gamma (IFN-gamma) down-regulates receptors associated with reverse cholesterol transport including ABCA1. In the present study, the kinetics and mechanism of ABCA1 down-regulation were determined in mouse peritoneal macrophages. IFN-gamma decreased ABCA1 mRNA 1h following IFN-gamma addition and was maximally reduced by 3h. Down-regulation was protein synthesis dependent and involved post-transcriptional processes. ABCA1 message had a T(1/2) of 115 min in actinomycin treated cells that was reduced to a T(1/2) of 37 min by IFN-gamma. The decrease in message stability was also associated with a rapid loss of ABCA1 protein, significant 3h following IFN-gamma addition. The kinetics of ABCA1 message and protein decrease was consistent with the early IFN-gamma-induced changes in Stat1 phosphorylation and nuclear translocation observed in these cells. Therefore, ABCA1 can be considered as an early response gene to macrophage activation by IFN-gamma with down-regulation occurring by message destabilization.
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Okopień B, Krysiak R, Kowalski J, Madej A, Belowski D, Zieliński M, Labuzek K, Herman ZS. The effect of statins and fibrates on interferon-γ and interleukin-2 release in patients with primary type II dyslipidemia. Atherosclerosis 2004; 176:327-35. [PMID: 15380456 DOI: 10.1016/j.atherosclerosis.2004.05.009] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2003] [Revised: 05/07/2004] [Accepted: 05/24/2004] [Indexed: 10/26/2022]
Abstract
The aim of the study was to assess the effect of two major groups of hypolipemic drugs, HMG-CoA reductase inhibitors (statins) and PPARalpha activators (fibrates), on the secretory function of T-lymphocytes in patients with primary type II dyslipidemia. Sixty-three patients with type IIa dyslipidemia were randomized to fluvastatin (40 mg daily; n = 33) or simvastatin (20mg daily; n = 30), while 68 type IIb dyslipidemic patients were treated with micronized ciprofibrate (100mg daily; n = 34) or micronized fenofibrate (200mg daily; n = 34). Lipid profile and cytokine (interferon-gamma and interleukin-2) release by phytohemagglutinin-stimulated lymphocytes were determined at the beginning of the study and after 30 and 90 days of treatment. Compared to healthy subjects (n = 59), both type IIa and IIb dyslipidemic patients exhibited higher baseline release of interferon-gamma and interleukin-2. Fluvastatin, simvastatin and, to a less extent, ciprofibrate and fenofibrate inhibited the release of both cytokines, but this effect did not correlate with their lipid-lowering potential. Hypolipemic agents also slightly reduced plasma interleukin-2 levels. Our study suggests that the beneficial effect of hypolipemic drugs involves their inhibitory action on the secretory function of T-lymphocytes. This lipid-independent action is stronger for statins than for fibrates and probably results from their "class" effect. The treatment-induced reduction in the release of both cytokines may contribute to the clinical effectiveness of statins and fibrates in the therapy of atherosclerosis and in the management of organ transplant recipients.
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Affiliation(s)
- Boguslaw Okopień
- Department of Clinical Pharmacology, Medical University of Silesia, Medyków 18, PL 40-752 Katowice, Poland
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Cheng SM, Yang SP, Ho LJ, Tsao TP, Chang DM, Lai JH. Irbesartan inhibits human T-lymphocyte activation through downregulation of activator protein-1. Br J Pharmacol 2004; 142:933-42. [PMID: 15210574 PMCID: PMC1575109 DOI: 10.1038/sj.bjp.0705785] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2003] [Revised: 02/20/2004] [Accepted: 03/09/2004] [Indexed: 11/08/2022] Open
Abstract
1 Irbesartan is a promising antihypertensive drug with beneficial effects on atherosclerotic processes. In the progression of atherosclerosis, human T-lymphocytes play an important role, but it is not yet known how irbesartan modulates human T-lymphocytes activation. To gain insight into the mechanisms by which irbesartan acts, we investigated its effects on human T-lymphocytes. 2 Primary human T-lymphocytes were isolated from whole blood. Cytokines were determined by ELISA. Activator protein-1 (AP-1) and related protein activities were determined by electrophoretic mobility shift assays, kinase assays, Western blotting and transfection assays. 3 Irbesartan inhibited the production of both tumor necrosis factor-alpha and interferon-gamma by activated T-cells, especially at therapeutic concentrations. Further investigation at the molecular level indicated that the inhibition of activated human T-lymphocytes specifically correlated with the downregulation of AP-1 DNA-binding activity. In the Jurkat T-cell line, irbesartan also inhibited AP-1 transcriptional activity. Finally, we revealed that irbesartan is unique in its ability to inhibit the activation of both c-Jun NH2-terminal protein kinase and p38 MAPK. 4 Our studies show that irbesartan may modulate inflammation-based atherosclerotic diseases through a cell-mediated mechanism involving suppression of human T-lymphocytes activation via downregulation of AP-1 activity.
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Affiliation(s)
- Shu-Meng Cheng
- Division of Cardiology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, No 325, Section 2, Cheng-Kung Road, Neihu 114, Taipei, Taiwan, ROC
| | - Shih-Ping Yang
- Division of Cardiology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, No 325, Section 2, Cheng-Kung Road, Neihu 114, Taipei, Taiwan, ROC
| | - Ling-Jun Ho
- Division of Gerontology Research, National Health Research Institute, No 325, Section 2, Cheng-Kung Road, Neihu 114, Taipei, Taiwan, ROC
| | - Tien-Ping Tsao
- Division of Cardiology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, No 325, Section 2, Cheng-Kung Road, Neihu 114, Taipei, Taiwan, ROC
| | - Deh-Ming Chang
- Division of Rheumatology/Immunology & Allergy, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, No 325, Section 2, Cheng-Kung Road, Neihu 114, Taipei, Taiwan, ROC
| | - Jenn-Haung Lai
- Division of Rheumatology/Immunology & Allergy, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, No 325, Section 2, Cheng-Kung Road, Neihu 114, Taipei, Taiwan, ROC
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20
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Légrádi A, Chitu V, Szukacsov V, Fajka-Boja R, Székely Szücs K, Monostori E. Lysophosphatidylcholine is a regulator of tyrosine kinase activity and intracellular Ca(2+) level in Jurkat T cell line. Immunol Lett 2004; 91:17-21. [PMID: 14757365 DOI: 10.1016/j.imlet.2003.10.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lysophospholipids, particularly lysophosphatidylcholine (lyso-PC), have been implicated in modulating T cell functions at the sites of inflammation and atherosclerosis. Although the chemotactic and immunomodulatory effects are well documented, the exact signaling pathway of lyso-PC action is poorly defined. In this work, we studied the earliest biochemical events in T cells triggered by lyso-PC. A marked and immediate tyrosine phosphorylation was induced in the leukemic T cell line, Jurkat. Phosphorylation of cellular substrates included src family kinase, p56(lck) and syk family kinase, ZAP70. The lyso-PC induced tyrosine phosphorylation was largely dependent on the presence of functional p56(lck). Tyrosine phosphorylation was followed by the elevation of intracellular Ca(2+) concentration. The magnitude of the mobilization of the intracellular Ca(2+) was similar in the absence of the p56(lck) activity in JCaM1.6 cells as in Jurkat cells, however, it was slightly but reproducibly delayed compared to that in the wild type cells. Inhibition of the Ser/Thr kinases and tyrosine kinases with staurosporine and genistein, respectively, decreased the rise in the intracellular Ca(2+) content. Moreover, pertussis toxin completely blocked the Ca(2+) signal supporting the role of the G-protein coupled LPC receptor in this event.
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Affiliation(s)
- Adám Légrádi
- Lymphocyte Signal Transduction Laboratory, Institute of Genetics, Biological Research Center of Hungarian Academy of Sciences, PO Box 521, Temesvári krt. 62, H-6726 Szeged, Hungary
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21
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Kim SH, Kang YJ, Kim WJ, Woo DK, Lee Y, Kim DI, Park YB, Kwon BS, Park JE, Lee WH. TWEAK Can Induce Pro-Inflammatory Cytokines and Matrix Metalloproteinase-9 in Macrophages. Circ J 2004; 68:396-9. [PMID: 15056843 DOI: 10.1253/circj.68.396] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The expression of TWEAK (TNFSF12) and TweakR/Fn14 was detected in regions rich in macrophage/foam cells in atherosclerotic plaques. The role of TWEAK in monocytes in relation to atherogenesis was investigated by analyzing the cellular events induced by TWEAK in a human macrophage-like cell line, THP-1. TWEAK induced various molecular mediators of atherogenesis, such as IL-6, MCP-1, IL-8 and MMP-9, and the induction was augmented by interferon-gamma. TWEAK-induced activation of MMP-9 was mediated by activation of NF-kappaB. These results suggest that TWEAK is involved in atherosclerosis by inducing pro-inflammatory cytokines and extracellular matrix degrading enzymes, which reduce plaque stability.
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Affiliation(s)
- Se-Hwa Kim
- Cardiology Division, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
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22
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Abstract
This review focuses on the role of monocytes in the early phase of atherogenesis, before foam cell formation. An emerging consensus underscores the importance of the cellular inflammatory system in atherogenesis. Initiation of the process apparently hinges on accumulating low-density lipoproteins (LDL) undergoing oxidation and glycation, providing stimuli for the release of monocyte attracting chemokines and for the upregulation of endothelial adhesive molecules. These conditions favor monocyte transmigration to the intima, where chemically modified, aggregated, or proteoglycan- or antibody-complexed LDL may be endocytotically internalized via scavenger receptors present on the emergent macrophage surface. The differentiating monocytes in concert with T lymphocytes exert a modulating effect on lipoproteins. These events propagate a series of reactions entailing generation of lipid peroxides and expression of chemokines, adhesion molecules, cytokines, and growth factors, thereby sustaining an ongoing inflammatory process leading ultimately to lesion formation. New data emerging from studies using transgenic animals, notably mice, have provided novel insights into many of the cellular interactions and signaling mechanisms involving monocytes/macrophages in the atherogenic processes. A number of these studies, focusing on mechanisms for monocyte activation and the roles of adhesive molecules, chemokines, cytokines and growth factors, are addressed in this review.
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Affiliation(s)
- Bjarne Osterud
- Department of Biochemistry, Institute of Medical Biology, Faculty of Medicine, University of Tromsø, Tromsø, Norway.
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23
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Abstract
Atherosclerosis is an inflammatory disease. T lymphocytes, occurring concomitantly with macrophages, are found in atherosclerotic lesions with substantial numbers in all stages. Most of the T cells in the lesions are CD4(+) T cells. The finding of activated T cells and macrophages in lesions and cloning of T cells specific for modified low-density lipoproteins from lesions suggest that a cell-mediated immune reaction is taking place in atherosclerosis. This review provides an overview of our current understanding of the roles of CD4(+) T cell subpopulations in atherosclerosis.
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Affiliation(s)
- Xinghua Zhou
- Center for Molecular Medicine L8:03 and Department of Medicine, Karolinska Hospital, Karolinska Institutet, 17176, Stockholm, Sweden.
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24
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Xia M, Ling WH, Ma J, Kitts DD, Zawistowski J. Supplementation of diets with the black rice pigment fraction attenuates atherosclerotic plaque formation in apolipoprotein e deficient mice. J Nutr 2003; 133:744-51. [PMID: 12612147 DOI: 10.1093/jn/133.3.744] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Apolipoprotein (apo)E-deficient mice were used to study the antiatherogenic effect of black rice pigment fraction (BRF) and the possible mechanisms by which it inhibits atherogenesis. The apoE-deficient mice (n = 45) were randomly divided into three groups and received AIN-93G diet (positive group), AIN-93G with 5 g of black rice pigment fraction/100 g (BRF group) and AIN-93G with 5 g of white rice outer layer fraction/100 g (WRF group) for 16 wk. C57BL/6J mice (n = 15) received AIN-93G and were used as a control group. Blood samples were collected for measurement of lipid concentration, antioxidized LDL antibody and nitric oxide concentration. Livers were extracted for determination of cholesterol concentrations, and aortas were used to determine cholesterol concentrations and inducible nitric oxide synthase protein and mRNA expression. Hearts were used to assess atherosclerotic plaque formation. The apoE-deficient mice fed the black rice pigment fraction diet had 48% (P < 0.01) less atherosclerotic lesion area compared with apoE-deficient mice fed only the AIN-93G diet and 46% (P < 0.01) less lesion area compared with mice fed the white rice outer layer fraction diet. This observation corresponded with significantly (P < 0.05) lower total serum cholesterol, lower liver and aorta cholesterol (P < 0.01) and higher HDL cholesterol (P < 0.05) concentrations and lower (P < 0.05) antioxidized LDL antibody titer in apoE-deficient mice fed the black rice pigment fraction diet compared with positive and WRF groups. Notwithstanding this, mice fed the black rice pigment fraction diet also had lower CD4(+) T lymphocyte expression (P < 0.05) and weaker inducible nitric oxide synthase expression (P < 0.05) compared with mice fed the AIN-93G diet and the white rice outer layer fraction diet, respectively. We concluded that the inhibition of atherosclerotic lesions of the black rice pigment fraction is attributed to the improvement in cholesterol accumulation and reduction in oxidative stress and inflammation.
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Affiliation(s)
- Min Xia
- Department of Clinical Nutrition, School of Public Health, Sun Yet-sen University (Northern Campus), Guangzhou, 510080, People's Republic of China
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25
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Kunjathoor VV, Febbraio M, Podrez EA, Moore KJ, Andersson L, Koehn S, Rhee JS, Silverstein R, Hoff HF, Freeman MW. Scavenger receptors class A-I/II and CD36 are the principal receptors responsible for the uptake of modified low density lipoprotein leading to lipid loading in macrophages. J Biol Chem 2002; 277:49982-8. [PMID: 12376530 DOI: 10.1074/jbc.m209649200] [Citation(s) in RCA: 734] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Modification of low density lipoprotein (LDL) can result in the avid uptake of these lipoproteins via a family of macrophage transmembrane proteins referred to as scavenger receptors (SRs). The genetic inactivation of either of two SR family members, SR-A or CD36, has been shown previously to reduce oxidized LDL uptake in vitro and atherosclerotic lesions in mice. Several other SRs are reported to bind modified LDL, but their contribution to macrophage lipid accumulation is uncertain. We generated mice lacking both SR-A and CD36 to determine their combined impact on macrophage lipid uptake and to assess the contribution of other SRs to this process. We show that SR-A and CD36 account for 75-90% of degradation of LDL modified by acetylation or oxidation. Cholesteryl ester derived from modified lipoproteins fails to accumulate in macrophages taken from the double null mice, as assessed by histochemistry and gas chromatography-mass spectrometry. These results demonstrate that SR-A and CD36 are responsible for the preponderance of modified LDL uptake in macrophages and that other scavenger receptors do not compensate for their absence.
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Affiliation(s)
- Vidya V Kunjathoor
- Lipid Metabolism Unit, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
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26
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Whitman SC, Ravisankar P, Daugherty A. IFN-gamma deficiency exerts gender-specific effects on atherogenesis in apolipoprotein E-/- mice. J Interferon Cytokine Res 2002; 22:661-70. [PMID: 12162876 DOI: 10.1089/10799900260100141] [Citation(s) in RCA: 140] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
We have shown recently that administration of exogenous interferon-gamma (IFN-gamma) to apolipoprotein E (apoE)(-/-) mice augmented atherogenesis. In the present study, we examined whether deficiency of endogenous IFN-gamma would reduce atherosclerosis in apoE(-/-) mice. Compound-deficient mice were generated by crossing strain-matched IFN-gamma(-/-) and apoE(-/-) mice and comparing them to apoE(-/-) mice. Groups of both genders were fed either a normal or a high-fat diet. IFN-gamma deficiency did not affect serum cholesterol concentrations or lipoprotein-cholesterol distributions in any groups. IFN-gamma deficiency had no effect on serum triglyceride concentrations, except for an increase noted in males fed a normal diet. The extent of atherosclerosis was determined in tissue sections of the ascending aorta and on the surface of the aortic arch. During feeding of normal diets, IFN-gamma deficiency had no effect on the extent of atherosclerosis in female mice in either vascular bed. In contrast, in male mice fed normal diet, IFN-gamma deficiency markedly decreased lesion size in both vascular beds. During feeding of high-fat diets, IFN-gamma deficiency also had no effect on lesion size in females but profoundly decreased lesion size in the aortic root of male mice. IFN-gamma deficiency had no effect on the abundance of T lymphocytes or MHC class II-positive cells in aortic root lesions of females. By comparison, both these parameters were reduced in lesions of male mice. Therefore, IFN-gamma deficiency decreased atherogenesis, potentially by decreasing T lymphocyte presence and cell activation, without influencing serum cholesterol concentrations. However, this effect is strikingly restricted to male mice.
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Affiliation(s)
- Stewart C Whitman
- University of Ottawa Heart Institute, Ottawa, Ontario, Canada, K1Y 4W7
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27
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Zuckerman SH, Kauffman RF, Evans GF. Peroxisome proliferator-activated receptor alpha,gamma coagonist LY465608 inhibits macrophage activation and atherosclerosis in apolipoprotein E knockout mice. Lipids 2002; 37:487-94. [PMID: 12056591 DOI: 10.1007/s11745-002-0922-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The apolipoprotein E (apoE) knockout mouse has provided an approach to the investigation of the effect of both cellular and humoral processes on atherosclerotic lesion progression. In the present study, pharmacologic modulation of both interferon gamma (IFNgamma)-inducible macrophage effector functions, and atherosclerotic lesions in the apoE knockout mouse were investigated using the peroxisome proliferator-activated receptor (PPAR) alpha,gamma coagonist LY465608. LY465608 inhibited, in a concentration-dependent manner, IFNgamma induction of both nitric oxide synthesis and the beta 2 integrin CD11a in elicited peritoneal macrophages from apoE knockout mice. Similar effects were observed ex vivo following 10 d of treating mice with 10 mg/kg of LY465608. Treatment of apoE knockout mice for 18 wk with LY465608 resulted in a statistically significant 2.5-fold reduction in atherosclerotic lesion area in en face aorta preparations. These effects were apparent in the absence of any reduction in total serum cholesterol or in lipoprotein distribution. Finally, treatment of apoF knockout mice with established atherosclerotic disease resulted in a modest but not statistically significant decrease in aortic lesional surface area. These results demonstrate the utility of PPAR coagonists in reducing the progression of the atherosclerotic lesion.
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Affiliation(s)
- Steven H Zuckerman
- Division of Cardiovascular Research, Lilly Research Laboratories, Indianapolis, Indiana 46285, USA.
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28
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Babaei S, Stewart DJ, Picard P, Monge JC. Effects of VasoCare therapy on the initiation and progression of atherosclerosis. Atherosclerosis 2002; 162:45-53. [PMID: 11947896 DOI: 10.1016/s0021-9150(01)00680-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
VasoCare therapy, which involves the administration of autologous blood following the ex vivo exposure to physico-chemical stressors, has been shown to modulate immune responses. Since immune mechanisms have been recognized to be pivotal in the pathogenesis of atherosclerosis, we hypothesized that VasoCare treatment would inhibit atherosclerosis in LDL-R (-/-) mice. Three groups of LDL-R (-/-) mice were studied: a control group that was fed normal chow (Group I) and no other treatment; a control group that received a high cholesterol (HC) diet for 8 weeks (group II) with sham saline injections; and a third group (III) that received HC diet for 8 weeks and VasoCare treatment initiated after four weeks of HC feeding. Atherosclerotic area (AA), relative to total aortic area (TA), was assessed after 8 weeks of HC feeding by oil red O staining, and cross sectional plaque area at the level of the aortic valve leaflets was determined by quantitative morphometry. HC mice exhibited substantial aortic lipid deposition which was profoundly reduced in the VasoCare treated animals (AA/TA ratios in group II: 0.32+/-0.15 vs. group III: 0.17+/-0.06; P<0.05). This was associated with a significant decrease in cross sectional area of plaque in the aortic sinuses. VasoCare therapy also reduced the xanthoma formation and limb swelling characteristic of this animal model. However, cholesterol levels, measured by an enzymatic assay, showed similar marked increases in total serum cholesterol (CHO) in the animals receiving HC diet alone and those receiving the HC diet and VasoCare treatment [group I: 5.4+/-0.8 mM, group II: 46.7+/-3.6 mM, and group III: 44.7+/-2.8 mM (P<0.01 vs. group I)]. We conclude that VasoCare treatment inhibits progression of atherosclerotic lesions in a murine model of human familial hypercholesterolemia by a mechanism independent of cholesterol lowering.
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Affiliation(s)
- Saeid Babaei
- Terrence Donnelly Vascular Biology Laboratory, Terrence Donnelly Heart Center, Division of Cardiology, St. Michael's Hospital, 30 Bond Street, Toronto Ont., Canada M5B 1W8
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29
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Lada AT, Willingham MC, St. Clair RW. Triglyceride depletion in THP-1 cells alters cholesteryl ester physical state and cholesterol efflux. J Lipid Res 2002. [DOI: 10.1016/s0022-2275(20)31492-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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30
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Yamanouchi J, Takatori A, Nishida E, Kawamura S, Yoshikawa Y. Expression of lipoprotein receptors in the aortic walls of diabetic APA hamsters. Exp Anim 2002; 51:33-41. [PMID: 11871150 DOI: 10.1538/expanim.51.33] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Syrian hamsters of the APA strain (APA hamsters) have recently been demonstrated to develop atheromatous lesions in the aortic arches under the diabetic condition induced by a single injection of streptozotocin (SZ). Various lipoprotein receptors are reported to play important roles in atherogenesis mainly in vitro, while there are few reports on the relative expressions of these receptors in vivo. In this study, we therefore examined messenger RNA (mRNA) expressions of several lipoprotein receptors on the aortic arches of diabetic APA hamsters at 6, 14 and 26 weeks after the injection (WAI) of SZ. In semi-quantitative RT-PCR, scavenger receptor (SR)-AI, macrosialin (MS)/CD68, and receptor for advanced glycation end-products (RAGE) mRNAs showed significant increases at 6 WAI of SZ, and SR-AI and CD36 mRNA obviously increased until 26 WAI, as compared with the control. Low-density lipoprotein receptor mRNA showed a significant decrease at 14 and 26 WAI, and SR-BI mRNA significantly decreased at 6 and 14 WAI, as compared with the control. Very low-density lipoprotein receptor mRNA was at the same level as the control. By means of in situ hybridization, SR-AI, MS/CD68 and RAGE mRNA were detected in the foam cells of the fatty streaks at 6 WAI, which suggested that SR-AI, MS/CD68 and RAGE play crucial roles in the formation of the fatty streaks, the initial lesions of atherogenesis in diabetic APA hamsters. SR-AI and CD36 were also believed to be related to the progression of atherogenesis in this model.
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Affiliation(s)
- Jun Yamanouchi
- Department of Biomedical Science, Graduate School of Agricultural and Life Sciences, University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
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31
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Immune complexes and IFN-γ decrease cholesterol 27-hydroxylase in human arterial endothelium and macrophages. J Lipid Res 2001. [DOI: 10.1016/s0022-2275(20)31518-2] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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32
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Abstract
The scope of this review is to discuss the new advances in our understanding of the role of scavenger receptor class A in the initiation and modulation of the atherosclerotic process. Through the approaches of gene manipulation in the mouse model, a substantial body of literature has accumulated that depicts scavenger receptor class A as a central player in atherogenesis. In studies of scavenger receptor class A overexpression in macrophages through bone marrow transplantation using transgenic donor material, recipient mice with hyperlipidemia caused either by apolipoprotein E or LDL receptor deficiency did not show convincing changes in the degree of atherosclerosis development compared with controls. Conversely, the deletion of the scavenger receptor class A gene in the mouse has shown, in a consistent and significant fashion, that this receptor serves a pro-atherogenic function under hyperlipidemic conditions, as both apolipoprotein E and LDL receptor-deficient mice had reduced atherosclerosis in the absence of scavenger receptor class A. In addition, we have recently shown that C57BL/6 mice are protected from diet-induced atherosclerosis when they lack scavenger receptor class A, and that the macrophage is the cell type responsible for the effect of scavenger receptor class A deficiency in reducing lesion formation in C57BL/6 and LDL receptor null mice. Together, these results demonstrate that macrophage scavenger receptor class A contributes significantly to atherosclerotic lesion formation, and suggest that the uptake of oxidized or modified lipoproteins by vessel wall macrophages is a central process in atherogenesis.
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Affiliation(s)
- M F Linton
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
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33
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Sampedro MC, Motrán C, Gruppi A, Kivatinitz SC. VLDL modulates the cytokine secretion profile to a proinflammatory pattern. Biochem Biophys Res Commun 2001; 285:393-9. [PMID: 11444855 DOI: 10.1006/bbrc.2001.5202] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Human very-low-density lipoprotein (VLDL) inhibits DNA synthesis in lymphocytes activated by the nonspecific mitogen concanavalin A (Con A). We studied the effects of VLDL on lymphocyte activation (IL-2 receptor expression), cell cycle progression, and production of IL-2 and of IL-4 (a proinflammatory and an anti-inflammatory interleukin, respectively) to understand why an atherogenic lipoprotein inhibits cell proliferation. After 48 h of stimulation with the mitogen, VLDL decreased the population of cells bearing IL-2 receptor and the population of T-cells that progress through the cell cycle, increasing the population of T-cells in G(0)/G(1). Cells cultured in the presence of Con A and VLDL produced higher levels of IL-2 and lower levels of IL-4 than cells cultured without VLDL. These results suggest that VLDL inhibits lymphocyte proliferation by reducing IL-2 receptor and enhancing the levels of IL-2. Probably, one atherogenic effect of VLDL is to modulate the cytokine secretion profile of lymphocytes to a predominantly proinflammatory response.
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Affiliation(s)
- M C Sampedro
- Departamento de Química Biológica, Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC, UNC-CONICET), Ciudad Universitaria, 5000 Córdoba, Argentina
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34
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Yang JB, Duan ZJ, Yao W, Lee O, Yang L, Yang XY, Sun X, Chang CC, Chang TY, Li BL. Synergistic transcriptional activation of human Acyl-coenzyme A: cholesterol acyltransterase-1 gene by interferon-gamma and all-trans-retinoic acid THP-1 cells. J Biol Chem 2001; 276:20989-98. [PMID: 11399774 DOI: 10.1074/jbc.m011488200] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Acyl-coenzyme A:cholesterol acyltransferase (ACAT) is an intracellular enzyme involved in cellular cholesterol homeostasis and in atherosclerotic foam cell formation. Human ACAT-1 gene contains two promoters (P1 and P7), each located in a different chromosome (1 and 7) (Li, B. L., Li, X. L., Duan, Z. J., Lee, O., Lin, S., Ma, Z. M., Chang, C. C., Yang, X. Y., Park, J. P., Mohandas, T. K., Noll, W., Chan, L., and Chang, T. Y. (1999) J. Biol Chem. 274, 11060-11071). Interferon-gamma (IFN-gamma), a cytokine that exerts many pro-atherosclerotic effects in vivo, causes up-regulation of ACAT-1 mRNA in human blood monocyte-derived macrophages and macrophage-like cells but not in other cell types. To examine the molecular nature of this observation, we identified within the ACAT-1 P1 promoter a 159-base pair core region. This region contains 4 Sp1 elements and an IFN-gamma activated sequence (GAS) that overlaps with the second Sp1 element. In the monocytic cell line THP-1 cell, the combination of IFN-gamma and all-trans-retinoic acid (a known differentiation agent) enhances the ACAT-1 P1 promoter but not the P7 promoter. Additional experiments showed that all-trans-retinoic acid causes large induction of the transcription factor STAT1, while IFN-gamma causes activation of STAT1 such that it binds to the GAS/Sp1 site in the ACAT-1 P1 promoter. Our work provides a molecular mechanism to account for the effect of IFN-gamma in causing transcriptional activation of ACAT-1 in macrophage-like cells.
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Affiliation(s)
- J B Yang
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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35
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Hsu HY, Twu YC. Tumor necrosis factor-alpha -mediated protein kinases in regulation of scavenger receptor and foam cell formation on macrophage. J Biol Chem 2000; 275:41035-48. [PMID: 10969071 DOI: 10.1074/jbc.m003464200] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We previously reported tumor necrosis factor-alpha (TNF) modulates transcriptional and post-transcriptional down-regulation of macrophage scavenger receptor (MSR) (Hsu, H. Y., Nicholson, A. C., and Hajjar, D. P. (1996) J. Biol. Chem. 271, 7767-7773); however, TNF-mediated signaling mechanisms are unknown. Here, we demonstrate that ligation of TNF receptor stimulates activity of p21-activated protein kinase (PAK) and mitogen-activated protein kinases (MAPK) as follows: ERK, JNK, and p38 in murine macrophage J774A.1 cells. Upon activation of protein kinases (PK), TNF rapidly increases MSR message and protein; later it markedly reduces MSR expression. Studies using PK inhibitors and dominant negative constructs demonstrate phosphatidylinositol 3-kinase/Rac1/PAK/JNK and phosphatidylinositol 3-kinase/Rac1/PAK/p38 pathways contribute to important roles in the late stage of TNF down-regulation of MSR expression and taking up of OxLDL. Alternatively, the PKC/MEK1/ERK pathway in the early stage plays a significant role in up-regulation of the MSR gene. By using anti-TNF-R1 agonist antibody, we further confirm TNF-R1-mediated MAPK in regulation of MSR. Furthermore, in MSR gene promoter-driven luciferase reporter assays with TNF, PKC activator increases, but antioxidant N-acetylcysteine, PK inhibitors, and dominant negative constructs decrease luciferase activity in MSR gene promoter-transfected cells. Our current results show the first evidence of crucial roles for TNF-mediated MAPK pathways in the transcriptional regulation of MSR gene and increase MSR expression; in contrast, with TNF longer treatment the pathways down-regulate MSR and foam cell formation probably via post-transcriptional process.
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Affiliation(s)
- H Y Hsu
- Faculty of Medical Technology, Institute of Biotechnology in Medicine, National Yang-Ming University, 112 Taipei, Taiwan
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36
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Zuckerman SH, Panousis C, Mizrahi J, Evans G. The effect of gamma-interferon to inhibit macrophage-high density lipoprotein interactions is reversed by 15-deoxy-delta12,14-prostaglandin J2. Lipids 2000; 35:1239-47. [PMID: 11132183 DOI: 10.1007/s11745-000-0640-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Macrophage activation has been recognized as playing a central role in chronic inflammatory diseases in general and, more specifically, in the vascular wall during the progression of atherosclerotic lesions. Macrophage-activating factors present within the atherosclerotic lesion include the colony-stimulating factors and gamma interferon (IFNgamma). In the present study, the effects of IFNgamma on macrophage binding and uptake of fluorochrome-labeled high density lipoprotein (HDL) were investigated by flow cytometry and by measuring the amount of the type B scavenger receptors CD36 and scavenger receptor type B (SR-BI) by Northern blot analysis. IFNgamma-, but not granulocyte macrophage colony-stimulating factor (GM-CSF)-treated murine peritoneal macrophages displayed a two- to threefold decrease in Dil-labeled HDL uptake. This effect was observed in the absence of a comparable decrease in SR-BI message and protein or CD36 message. This decrease in both HDL binding and uptake was reversed by the peroxisome proliferator-activated receptor gamma (PPARgamma) agonist, 15-deoxy-delta12,4-prostaglandin J2 (15d-PGJ2), which also inhibited the IFNgamma induction of the beta2 integrin CD11a. Furthermore, 15d-PGJ2 increased the expression of SR-BI and CD36 message and SR-BI protein which was reflected in an increase in HDL binding and uptake. These results suggest a role for PPARgamma agonists in modulating the IFNgamma-mediated macrophage effector functions relevant to atherosclerotic disease progression.
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Affiliation(s)
- S H Zuckerman
- Division of Cardiovascular Research, Lilly Research Labs, Indianapolis, Indiana 46285, USA.
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37
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Abstract
Transition metal ion-mediated oxidation is a commonly used model system for studies of the chemical, structural, and functional modifications of low-density lipoprotein (LDL). The physiological relevance of studies using free metal ions is unclear and has led to an exploration of free metal ion-independent mechanisms of oxidation. We and others have investigated the role of human ceruloplasmin (Cp) in oxidative processes because it the principal copper-containing protein in serum. There is an abundance of epidemiological data that suggests that serum Cp may be an important risk factor predicting myocardial infarction and cardiovascular disease. Biochemical studies have shown that Cp is a potent catalyst of LDL oxidation in vitro. The pro-oxidant activity of Cp requires an intact structure, and a single copper atom at the surface of the protein, near His(426), is required for LDL oxidation. Under conditions where inhibitory protein (such as albumin) is present, LDL oxidation by Cp is optimal in the presence of superoxide, which reduces the surface copper atom of Cp. Cultured vascular endothelial and smooth muscle cells also oxidize LDL in the presence of Cp. Superoxide release by these cells is a critical factor regulating the rate of oxidation. Cultured monocytic cells, when activated by zymosan, can oxidize LDL, but these cells are unique in their secretion of Cp. Inhibitor studies using Cp-specific antibodies and antisense oligonucleotides show that Cp is a major contributor to LDL oxidation by these cells. The role of Cp in lipoprotein oxidation and atherosclerotic lesion progression in vivo has not been directly assessed and is an important area for future studies.
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Affiliation(s)
- P L Fox
- Department of Cell Biology, The Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA.
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38
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Morganelli PM, Kennedy SM, Mitchell TI. Differential effects of interferon-γ on metabolism of lipoprotein immune complexes mediated by specific human macrophage Fcγ receptors. J Lipid Res 2000. [DOI: 10.1016/s0022-2275(20)34479-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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39
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Panousis CG, Zuckerman SH. Regulation of cholesterol distribution in macrophage-derived foam cells by interferon-γ. J Lipid Res 2000. [DOI: 10.1016/s0022-2275(20)32076-9] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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40
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Hort W, Schwartzkopff B. Anatomie und Pathologie der Koronararterien. PATHOLOGIE DES ENDOKARD, DER KRANZARTERIEN UND DES MYOKARD 2000. [DOI: 10.1007/978-3-642-56944-9_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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41
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Frostegård J, Ulfgren AK, Nyberg P, Hedin U, Swedenborg J, Andersson U, Hansson GK. Cytokine expression in advanced human atherosclerotic plaques: dominance of pro-inflammatory (Th1) and macrophage-stimulating cytokines. Atherosclerosis 1999; 145:33-43. [PMID: 10428293 DOI: 10.1016/s0021-9150(99)00011-8] [Citation(s) in RCA: 692] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The atherosclerotic lesion contains large numbers of macrophages and T lymphocytes. This suggests that a cellular immune response may take place in the lesion, and oxidized lipoproteins, heat shock proteins, and micro-organisms have been implied as candidate antigens. However, the effector mechanisms elicited by this response have been largely unclear. We have therefore analyzed endarterectomy specimens by immunohistochemistry and reverse transcription-PCR to detect immune cytokines produced by immunocompetent cells of the advanced human plaque. The pro-inflammatory T cell cytokines, interleukin-2 and interferon-7, were found in a large proportion of plaques (IL-2 in 50% and interferon-gamma in 30% of plaques by immunohistochemistry and mRNA for both cytokines in 70% of plaques by PCR). In contrast, interleukin-4 and interleukin-5 were rarely observed (both cytokines in 10% of plaques by immunohistochemistry, mRNA for interleukin-4 in 10% and for interleukin-5 in 40% by PCR). This demonstrates the presence of a predominantly pro-inflammatory, Th1-type T cell response in atherosclerosis. This conclusion was further supported by the expression of the pro-inflammatory cytokine, interleukin-1 by plaque macrophages and endothelial cells. In addition, the chemokine interleukin-8 and the macrophage differentiation-stimulating cytokine, granulocyte-monocyte colony stimulating factor, were observed in plaque tissues, suggesting that the micro-environment promotes monocyte recruitment and macrophage differentiation. Occasional eosinophils and B cells were, however observed, which is compatible with a microheterogeneity within the lesion. Finally, the anti-inflammatory and fibrogenic cytokines, transforming growth factor-beta1-3 and its carrier protein, latent TGF-beta binding protein, were found in large amounts in all plaques. Together, these results show that a pro-inflammatory, Thl type cellular immune response takes place in the atherosclerotic plaque. The balance between pro-inflammatory and anti-inflammatory cytokines may be decisive for the progression of the lesion.
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Affiliation(s)
- J Frostegård
- Department of Medicine, Karolinska Hospital, Karolinska Institute, Stockholm, Sweden
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42
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Uptake of type IV hypertriglyceridemic VLDL by cultured macrophages is enhanced by interferon-γ. J Lipid Res 1999. [DOI: 10.1016/s0022-2275(20)33505-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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43
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de Winther MP, Gijbels MJ, van Dijk KW, van Gorp PJ, suzuki H, Kodama T, Frants RR, Havekes LM, Hofker MH. Scavenger receptor deficiency leads to more complex atherosclerotic lesions in APOE3Leiden transgenic mice. Atherosclerosis 1999; 144:315-21. [PMID: 10407492 DOI: 10.1016/s0021-9150(98)00332-3] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Apolipoprotein (apo) E3Leiden is a dysfunctional apo E variant associated with familial dysbetalipoproteinemia in humans. Transgenic mice carrying the APOE3Leiden gene develop hyperlipidemia and are highly susceptible to diet-induced atherosclerosis. An early step in atherosclerosis is foam cell formation, which is thought to result from the unrestricted uptake of modified lipoproteins by macrophages. To investigate the role of the macrophage scavenger receptor type I and II (MSR-A) in this process, APOE3Leiden transgenic mice were crossed onto a MSR-A deficient background and the development of atherosclerosis was examined. In view of recent results with apo E deficient mice (Suzuki H et al., A role for the macrophage scavenger receptors in atherosclerosis. Nature 1997; 386(6622):292-296), absence of the MSR-A in APOE3Leiden mice was expected to lead to a reduction of atherosclerosis. In our study we compared APOE3Leiden/MSR-A deficient mice (E3L MSR-A -/-) to APOE3Leiden/MSR-A wild-type mice (E3L MSR-A +/+). These animals were fed an atherogenic diet for 10 weeks. Quantification of the lesion area showed no significant difference between E3L MSR-A -/- and E3L MSR-A +/+ mice although there was a trend towards the development of larger lesions in the E3L MSR-A -/- mice. All lesions were typed according to their cellular composition. In both male and female E3L MSR-A -/- mice, significantly more severe lesions developed as compared to E3L MSR-A +/+ mice. These results indicate that the effect of MSR-A deficiency on atherogenesis may depend on the presence or absence of apo E.
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Affiliation(s)
- M P de Winther
- MGC-Department of Human Genetics, Leiden University Medical Center, The Netherlands
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44
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Nicoletti A, Caligiuri G, Törnberg I, Kodama T, Stemme S, Hansson GK. The macrophage scavenger receptor type A directs modified proteins to antigen presentation. Eur J Immunol 1999; 29:512-21. [PMID: 10064066 DOI: 10.1002/(sici)1521-4141(199902)29:02<512::aid-immu512>3.0.co;2-y] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Scavenger receptors constitute a family of cell surface receptors that internalize endotoxins, oxidized low-density lipoproteins (oxLDL) and other proteins with clustered negative charges for degradation in macrophages. They were recently proposed to play a role in antigen presentation but the type of scavenger receptor involved in this process has not been known. In this report, we have examined the cellular immune responses to modified proteins in mice lacking the SR-A scavenger receptor (SRAKO) and their wild-type (ICR) controls. While spleen cells of ICR mice immunized with maleylated murine serum albumin (Mal-MSA) exhibit strong proliferative responses to the antigen, no such responses were found in SRAKO mice. However, addition of SR-A+ antigen-presenting cells from ICR mice unmasked proliferative responses to Mal-MSA in spleen cultures of immunized SRAKO mice. Similarly, addition of SR-A+ antigen-presenting cells was necessary to detect T cell responses in spleen cultures of oxLDL-immunized SRAKO mice. This indicates that SR-A can mediate uptake of modified antigens for presentation to antigen-specific T cells. The fact that cellular immunity developed in SRAKO mice implies that other scavenger receptor(s) also internalize modified antigens for presentation in vivo. These observations show that scavenger receptors participate in immune recognition of oxidized protein antigens; this system may be important for recognition of damaged macromolecules but could also play a role in autoimmunity.
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Affiliation(s)
- A Nicoletti
- Center for Molecular Medicine, Karolinska Institute, Stockholm, Sweden
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45
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Hegele RA. Genetics in childhood atherosclerosis. PROGRESS IN PEDIATRIC CARDIOLOGY 1998. [DOI: 10.1016/s1058-9813(99)00008-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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46
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Abstract
Atherosclerosis is characterized as a chronic inflammatory-fibroproliferative disease of the vessel wall. The attachment of monocytes and T-lymphocytes to the injured endothelium followed by their migration into the intima is one of the first and most crucial steps in lesion development. The co-localization of CD4+ T-cells and macrophages in the lesion, the abundant expression of HLA Class II molecules and the co-stimulatory molecule CD40 and its ligand (CD40L) indicate a contribution of cell-mediated immunity to atherogenesis. Transgenic mouse models revealed that dependent on the model T- and B-cells may promote lesion progression, monocytes and macrophages are in contrast essential for the development of atherosclerotic lesions. Apart from the local process in the vessel wall, systemic signs of an inflammatory reaction are also associated with lesion development. Thus plasma levels of C-reactive protein and fibrinogen and the white blood cell count are positively correlated to the risk of cardiovascular disease. Recently, an inflammatory phenotype of circulating peripheral blood monocytes could be demonstrated as a specific cellular correlate to lipid and lipoprotein risk factors. Thus the pool size of LPS receptor (CD14)dim and Fc gamma IIIa receptor (CD16a)+ monocytes positively correlates to plasma cholesterol levels, to triglycerides levels and to the apolipoprotein E4 (apo E4) phenotype in contrast to a negative correlation to the high density lipoprotein (HDL) cholesterol concentration. This CD14dim CD16a+ monocytes are further characterized by a high expression of beta 1- and beta 2-integrins, suggesting a higher capacity for attachment at sites of inflammation. A proinflammatory cytokine pattern and an expansion of these cells in other inflammatory diseases are indicating that these cells promote the inflammatory process during atherogenesis. Surface expression of the activation antigen CD45RA on monocytes in correlation to plasma LDL cholesterol and Lp(a) levels further indicates an inflammatory reaction. Regarding the potential mechanisms of the phenotypic changes of peripheral blood monocytes, in a serum free in vitro differentiation model supplemented with M-CSF monocytes from probands which are homozygous for apo E4 showed a significantly higher increase of CD16a expression compared to apo E3/E3 cells indicating that a genetic polymorphism of a single apolipoprotein gene locus may affect monocyte differentiation. The further characterization of the cellular immunology of monocytes and T-lymphocytes in lesion development will provide new specific diagnostic and therapeutic targets in atherogenesis.
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Affiliation(s)
- G Schmitz
- Institute for Clinical Chemistry and Laborary Medicine, University of Regensburg.
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47
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Zhou X, Paulsson G, Stemme S, Hansson GK. Hypercholesterolemia is associated with a T helper (Th) 1/Th2 switch of the autoimmune response in atherosclerotic apo E-knockout mice. J Clin Invest 1998; 101:1717-25. [PMID: 9541503 PMCID: PMC508754 DOI: 10.1172/jci1216] [Citation(s) in RCA: 330] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Atherosclerosis is an inflammatory-fibrotic response to accumulation of cholesterol in the artery wall. In hypercholesterolemia, low density lipoproteins (LDL) accumulate and are oxidized to proinflammatory compounds in the arterial intima, leading to activation of endothelial cells, macrophages, and T lymphocytes. We have studied immune cell activation and the autoimmune response to oxidized LDL in atherosclerotic apo E-knockout mice. Autoantibodies to oxidized LDL exhibited subclass specificities indicative of T cell help, and the increase in antibody titers in peripheral blood was associated with increased numbers of cytokine-expressing T cells in the spleen. In addition to T cell-dependent antibodies, IgM antibodies to oxidized LDL were also increased in apo E-knockout mice. This suggests that both T cell-dependent and T cell-independent epitopes may be present on oxidized LDL. In moderate hypercholesterolemia, IgG antibodies were largely of the IgG2a isotype, suggesting that T cell help was provided by proinflammatory T helper (Th) 1 cells, which are prominent components of atherosclerotic lesions. In severe hypercholesterolemia induced by cholesterol feeding of apo E-knockout mice, a switch to Th2-dependent help was evident. It was associated with a loss of IFN-gamma-producing Th1 cells in the spleen, whereas IL-4-producing Th2 cells were more resistant to hypercholesterolemia. IFN-gamma but not IL-4 mRNA was detected in atherosclerotic lesions of moderately hypercholesterolemic apo E-knockout mice, but IL-4 mRNA appeared in the lesions when mice were made severely hypercholesterolemic by cholesterol feeding. These data show that IFN-gamma-producing Th1 cells infiltrate atherosclerotic lesions and provide T cell help for autoimmune responses to oxidized LDL in apo E-knockout mice. However, severe hypercholesterolemia is associated with a switch from Th1 to Th2, which results not only in the formation of IgG1 autoantibodies to oxidized LDL, but also in the appearance of Th2-type cytokines in the atherosclerotic lesions. Since the two subsets of T cells counteract each other, this switch may have important consequences for the inflammatory/immune process in atherosclerosis.
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Affiliation(s)
- X Zhou
- Centre for Molecular Medicine, Karolinska Institute, S-17176 Stockholm, Sweden
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48
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Yokota T, Ehlin-Henriksson B, Hansson GK. Scavenger receptors mediate adhesion of activated B lymphocytes. Exp Cell Res 1998; 239:16-22. [PMID: 9511720 DOI: 10.1006/excr.1997.3876] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The scavenger receptor (SR-A) is considered to play a role in host defense by scavenging endotoxins, oxidized proteins, and denatured or otherwise modified self components, which are routed toward degradation in macrophages. Recent data suggest that SR-A also functions as an adhesion molecule. Our previous finding of SR-A expression by high endothelial cells of venules and on follicular dendritic cells in peripheral lymph nodes prompted us to investigate whether SR-A can act as an addressin for lymphocytes. We describe here that activated B cells adhere to CHO cells transfected with either the type I or type II isoform of SR-A. In contrast, resting B cells isolated from peripheral blood did not adhere to SR-A transfected CHO cells. Other types of leukocytes did not bind to SR-A. The adhesive properties of B lymphocytes in different stages of activation were further explored using lymphoma cell lines of the B cell lineage. The in vitro EBV-transformed B cell line IARC171 showed enhanced adhesiveness to SR-A, whereas the Burkitt lymphoma cell lines, BL41, Rael, and Bl16 did not. The SR-A-dependent adhesion of B-lymphoblasts occurred both at 37 and 4 degrees C, suggesting that it was not dependent on cell metabolism. The known polyanionic ligands for SR-A, fucoidan, and acetylated low density lipoprotein, which bind to a positively charged portion of the collagen-like domain of SR-A, did not inhibit adhesion. This finding suggests that SR-A mediates adhesion of activated B lymphocytes through a binding site that differs from the one that binds polyanionic ligands. Together, our data suggest that SR-A plays a role in the recruitment of activated B cells into lymph nodes and inflammatory lesions by acting as an adhesion molecule for such cells.
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MESH Headings
- Animals
- Anticoagulants/pharmacology
- B-Lymphocytes/cytology
- B-Lymphocytes/immunology
- B-Lymphocytes/physiology
- Burkitt Lymphoma
- CHO Cells
- Cell Adhesion/drug effects
- Cell Adhesion/physiology
- Cell Line, Transformed
- Cells, Cultured
- Cricetinae
- Flow Cytometry
- Herpesvirus 4, Human/genetics
- Humans
- Interleukin-2/pharmacology
- Interleukin-4/pharmacology
- Ligands
- Lipoproteins, LDL/blood
- Lipoproteins, LDL/pharmacology
- Lymphocyte Activation
- Membrane Proteins
- Monocytes/physiology
- Polysaccharides/pharmacology
- Receptors, Immunologic/biosynthesis
- Receptors, Immunologic/physiology
- Receptors, Lipoprotein
- Receptors, Scavenger
- Recombinant Proteins/biosynthesis
- Recombinant Proteins/pharmacology
- Scavenger Receptors, Class A
- Scavenger Receptors, Class B
- Transfection
- Tumor Cells, Cultured
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Affiliation(s)
- T Yokota
- Center for Molecular Medicine, Karolinska Institute, Stockholm, Sweden
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49
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Weck KE, Dal Canto AJ, Gould JD, O'Guin AK, Roth KA, Saffitz JE, Speck SH, Virgin HW. Murine gamma-herpesvirus 68 causes severe large-vessel arteritis in mice lacking interferon-gamma responsiveness: a new model for virus-induced vascular disease. Nat Med 1997; 3:1346-53. [PMID: 9396604 DOI: 10.1038/nm1297-1346] [Citation(s) in RCA: 194] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Fundamental issues remain unresolved regarding the possible contribution of viruses to vascular pathology, as well as the role of the immune system in regulating these processes. Here we demonstrate that infection of mice with gamma-herpesvirus 68 (gammaHV68) provides a novel model for addressing these issues. Interferon-gamma receptor-deficient (IFNgammaR-/-) mice died weeks to months after gammaHV68 infection from a severe large-vessel panarteritis. GammaHV68-infected B cell-deficient and normal weanling mice exhibited milder large-vessel arteritis. Immunohistochemical analyses demonstrated gammaHV68 antigen in arteritic lesions and revealed a striking tropism of gammaHV68 for smooth muscle cells. These studies demonstrate that IFN-gamma is essential for control of chronic vascular pathology induced by gammaHV68 and suggest gamma-herpesviruses as candidate etiologic agents for human vasculitis.
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Affiliation(s)
- K E Weck
- Center for Immunology and Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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50
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Hajjar DP, Haberland ME. Lipoprotein trafficking in vascular cells. Molecular Trojan horses and cellular saboteurs. J Biol Chem 1997; 272:22975-8. [PMID: 9287290 DOI: 10.1074/jbc.272.37.22975] [Citation(s) in RCA: 137] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
During the pathogenesis of atherosclerosis, inflammatory cells such as the monocyte-derived macrophage accumulate in the vessel wall where they release cytokines. Initially, cytokines may assist in CE removal of lipoprotein-derived cholesterol/CE hydrolysis to clear intracellular lipid. When plasma levels of LDL become elevated, the vessel wall becomes lipid-engorged over time because it is unable to traffick the large amounts of endocytosed LDL-CE from the cell. In addition, lipoprotein entrapment by the extracellular matrix can lead to the progressive oxidation of LDL because of the action of lipoxygenases, reactive oxygen species, peroxynitrite, and/or myeloperoxidase. A range of oxidized LDL species is thus generated, ultimately resulting in their delivery to vascular cells through several families of scavenger receptors (Fig 1). These molecular Trojan horses and cellular saboteurs once formed or deposited in the cell can contribute to, and participate in, formation of macrophage- and smooth muscle-derived foam cells. A lipid-enriched fatty streak along the vessel wall can ensue. In addition to foam cell development, products of LDL peroxidation may activate endothelial cells, increase smooth muscle mitogenesis, or induce apoptosis because of the effects of oxysterols and products of lipid peroxidation (Fig 1). Because antioxidant defenses may be limited in the microenvironment of the cell or within LDL, the oxidation process continues to progress. Enzymes associated with HDL such as PAF acetylhydrolase and paraoxonase can participate in the elimination of biologically active lipids, but diminished cellular antioxidant activity coupled with low levels of HDL may allow acceleration of the clinical course of vascular disease. There is still much to be learned about how modified LDL initiate cellular signals that lead to inflammation, mitosis, or cholesterol accumulation. The present challenges include elucidation of the key signaling events that regulate lipoprotein-derived cholesterol trafficking in the vessel wall, which can impact on the pathogenesis of vascular disease.
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Affiliation(s)
- D P Hajjar
- Cornell University Medical College, New York, New York 10021 and UCLA School of Medicine, Los Angeles, California 90095, USA
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