351
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White GE, Tan TCC, John AE, Whatling C, McPheat WL, Greaves DR. Fractalkine has anti-apoptotic and proliferative effects on human vascular smooth muscle cells via epidermal growth factor receptor signalling. Cardiovasc Res 2009; 85:825-35. [PMID: 19840952 PMCID: PMC2819832 DOI: 10.1093/cvr/cvp341] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Aims Fractalkine (CX3CL1) is a membrane-bound chemokine that signals through the G protein-coupled receptor CX3CR1 that is implicated in the development of atherosclerosis. We have previously reported that CX3CR1 is expressed by primary human coronary artery smooth muscle cells (CASMC), where it mediates chemotaxis towards CX3CL1. We sought to determine the effect of CX3CL1 on CASMC survival and proliferation and elucidate the signalling mechanisms involved. Methods and results CX3CL1 significantly reduces staurosporine-induced apoptosis of CASMC, as quantified by caspase 3 immunostaining and Annexin-V flow cytometry. Furthermore, CX3CL1 is a potent mitogen for primary CASMC and induces phosphorylation of extracellular signal-regulated kinase (ERK) and Akt, measured by western blotting. Inhibition of either ERK or phosphoinositide 3-kinase (PI3K) signalling abrogates proliferation, while only PI3K signalling is involved in the anti-apoptotic effects of CX3CL1. We describe a novel and specific small molecule antagonist of CX3CR1 (AZ12201182) which abrogates the mitogenic and anti-apoptotic effects of CX3CL1 on CASMC. Pharmacological inhibition of the epidermal growth factor receptor (EGFR) blocks CASMC survival and DNA synthesis, indicating a previously undocumented role for EGFR signalling in response to CX3CL1 involving release of a soluble EGFR ligand. Specifically, CX3CL1 induces shedding of epiregulin and increases epiregulin mRNA expression 20-fold within 2 h. Finally, antibody neutralization of epiregulin abrogates the mitogenic effect of CX3CL1. Conclusion We have demonstrated two novel and important functions of CX3CL1 on primary human SMCs: anti-apoptosis and proliferation, both mediated via epiregulin-induced EGFR signalling. Our data have important implications in vascular pathologies including atherosclerosis, restenosis, and transplant accelerated arteriosclerosis, where the balance of SMC proliferation and apoptosis critically determines both plaque stability and vessel stenosis.
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Affiliation(s)
- Gemma E White
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
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352
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Gautier EL, Jakubzick C, Randolph GJ. Regulation of the migration and survival of monocyte subsets by chemokine receptors and its relevance to atherosclerosis. Arterioscler Thromb Vasc Biol 2009; 29:1412-8. [PMID: 19759373 DOI: 10.1161/atvbaha.108.180505] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Monocytes are central mediators in the advance of atherosclerotic plaque, making them a natural therapeutic target for reducing disease burden. Here, we highlight recent advances in our current understanding of monocyte heterogeneity and its relevance to regulation of monocyte accumulation and function within atherosclerotic plaques. Differences that distinguish monocyte subsets include differential expression of chemokine receptors, especially CCR2 and CX3CR1. Ablation of expression of these 2 receptors (or their ligands) in mice has an additive inhibition on monocyte recruitment to atherosclerotic plaques. Moreover, simultaneously interfering with 3 key pathways--CCR2, CX3CR1, and CCR5--essentially abolishes atherosclerosis in mice. Here, we discuss how these chemokine receptors act at multiple points on at least 1 monocyte subset, regulating their mobilization from bone marrow, survival, or recruitment to plaques. Finally, we discuss how this knowledge may be useful clinically, emphasizing that CX3CR1 may in particular be a viable target for therapeutic manipulation of monocyte-derived cell fate in cardiovascular disease.
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Affiliation(s)
- Emmanuel L Gautier
- Department of Gene and Cell Medicine, Mount Sinai School of Medicine, 1425 Madison Avenue, New York, NY 10029, USA
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353
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Abstract
Extravasation of polymorphonuclear leukocytes (PMNs) to the site of inflammation precedes a second wave of emigrating monocytes. That these events are causally connected has been established a long time ago. However, we are now just beginning to understand the molecular mechanisms underlying this cellular switch, which has become even more complex considering the emergence of monocyte subsets, which are affected differently by signals generated from PMNs. PMN granule proteins induce adhesion as well as emigration of inflammatory monocytes to the site of inflammation involving beta(2)-integrins and formyl-peptide receptors. Furthermore, modification of the chemokine network by PMNs and their granule proteins creates a milieu favoring extravasation of inflammatory monocytes. Finally, emigrated PMNs rapidly undergo apoptosis, leading to the discharge of lysophosphatidylcholine, which attracts monocytes via G2A receptors. The net effect of these mechanisms is the accumulation of inflammatory monocytes, thus promoting proinflammatory events, such as release of inflammation-sustaining cytokines and reactive oxygen species. As targeting PMNs without causing serious side effects seems futile, it may be more promising to aim at interfering with subsequent PMN-driven proinflammatory events.
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354
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Matzhold EM, Trummer O, Grünbacher G, Zulus B, Boehm BO, März W, Renner W. Association of polymorphisms in the chemokine receptor CX3CR1 gene with coronary artery disease. Cytokine 2009; 47:224-7. [PMID: 19628406 DOI: 10.1016/j.cyto.2009.06.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2008] [Revised: 06/24/2009] [Accepted: 06/27/2009] [Indexed: 12/01/2022]
Abstract
Two chemokine receptor CX3CR1 gene variants, V249I and T280M, have been implicated in coronary artery diseases (CAD). Currently no consistent effect has been revealed and their role in cardiovascular disease is still conflicting. In the present study the association of CX3CR1 genotypes with CAD and myocardial infarction (MI) was investigated in the Ludwigshafen Risk and Cardiovascular Health (LURIC) cohort, including 3316 individuals in whom cardiovascular disease angiographically has been defined or ruled out. Similarly to previous studies, the alleles I249 and M280 were in strong linkage disequilibrium and formed an I(249)M(280) haplotype. However, there was no relationship between CX3CR1 genotypes or corresponding haplotypes and the prevalence of CAD or MI. Adjusted for classical risk factors (age, sex, hypertension, dyslipidemia, diabetes mellitus and smoking), the odds ratio (OR) of V249I for CAD was 0.95 (95% confidence interval (CI)=0.78-1.15, p=0.61). The OR of T280M for CAD was 0.83 (95% CI=0.66-1.04, p=0.11). Furthermore, CX3CR1 variants were not associated with C-reactive protein levels, age at onset of CAD, severity of CAD and MI. In conclusion, present data of LURIC do not support the hypothesis that common variants of the CX3CR1 gene are associated with the presence of CAD or MI.
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Affiliation(s)
- Eva M Matzhold
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University, Graz, Austria
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355
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Stepanian A, Benchenni S, Beillat-Lucas T, Omnes S, Defay F, Peynaud-Debayle E, Baron G, Le Querrec A, Dreyfus M, Salomon L, Tsatsaris V, de Prost D, Mandelbrot L. Search for an association between V249I and T280M CX3CR1 genetic polymorphisms, endothelial injury and preeclampsia: the ECLAXIR study. PLoS One 2009; 4:e6192. [PMID: 19587779 PMCID: PMC2702686 DOI: 10.1371/journal.pone.0006192] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Accepted: 06/08/2009] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Preeclampsia and coronary-artery disease share risk factors, suggesting common pathophysiological mechanisms. CX3CR1/CX3CL1 mediates leukocyte migration and adhesion and has been implicated in the pathophysiology of several inflammatory diseases. M280/I249 variants of CX3CR1 are associated with an atheroprotective effect and reduced endothelial dysfunction. The aim of this study was to search for an association between V249I and T280M polymorphisms of CX3CR1, preeclampsia and endothelial dysfunction. METHODOLOGY/PRINCIPAL FINDINGS We explored these polymorphisms with real-time polymerase chain reaction in a case-control study (184 white women with preeclampsia and 184 matched normotensive pregnant women). Endothelial dysfunction biomarkers including von Willebrand factor, VCAM-1 and thrombomodulin, as well as the soluble form of CX3CL1 were measured by enzyme-linked immunosorbent assays (ELISA). The I249 and M280 alleles were associated neither with preeclampsia, nor with its more severe form or with endothelial injury. In contrast, we found a trend toward increased CX3CL1 levels in preeclampsia patients, especially in early-onset- preeclampsia as compared to its level in later-onset- preeclampsia. CONCLUSIONS/SIGNIFICANCE This is the first study to characterize the CX3CR1 gene polymorphisms in patients with preeclampsia. We found no differences in genotype or haplotype frequencies between patients with PE and normal pregnancies, suggesting that maternal CX3CR1 V249I and T280M polymorphisms do not increase susceptibility to preeclampsia. Further studies should be performed to directly evaluate the pathophysiological role of CX3CL1, a molecule abundantly expressed in endometrium, which has been shown to stimulate human trophoblast migration.
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Affiliation(s)
- Alain Stepanian
- AP-HP, Hôpital Louis Mourier, Service d'Hématologie Biologique, Colombes, France
- CIB Phénogen du GHU Nord, Paris, France
| | - Soraya Benchenni
- AP-HP, Hôpital Louis Mourier, Service d'Hématologie Biologique, Colombes, France
| | - Tiphaine Beillat-Lucas
- CHU Clémenceau, Unité de Gynécologie-Obstétrique et Médecine de la Reproduction, Caen, France
| | - Sophie Omnes
- AP-HP, Hôpital Bichat-Claude-Bernard, Service de Gynécologie-Obstétrique, Paris, France
| | - Fannie Defay
- AP-HP, Hôpital Bichat-Claude Bernard, Département d'Epidémiologie, Biostatistique et Recherche Clinique, Paris, France
| | - Edith Peynaud-Debayle
- AP-HP, Hôpital Louis Mourier, Service d'Hématologie Biologique, Colombes, France
- CIB Phénogen du GHU Nord, Paris, France
| | - Gabriel Baron
- AP-HP, Hôpital Bichat-Claude Bernard, Département d'Epidémiologie, Biostatistique et Recherche Clinique, Paris, France
| | - Agnès Le Querrec
- CHU Côte de Nacre, Service d'Hématologie Biologique, Caen, France
| | - Michel Dreyfus
- CHU Clémenceau, Unité de Gynécologie-Obstétrique et Médecine de la Reproduction, Caen, France
| | - Laurence Salomon
- AP-HP, Hôpital Louis Mourier, Département de Santé Publique (Evaluation, Recherche Clinique, Information médicale, Vigilances)–(DIM), Colombes, France
| | - Vassilis Tsatsaris
- AP-HP, Groupe Hospitalier Cochin Saint-Vincent de Paul, Service de Gynécologie-Obstétrique, Paris, France
| | - Dominique de Prost
- AP-HP, Hôpital Louis Mourier, Service d'Hématologie Biologique, Colombes, France
- CIB Phénogen du GHU Nord, Paris, France
- Université Paris 7–Denis Diderot, Paris, France
| | - Laurent Mandelbrot
- AP-HP, Hôpital Louis Mourier, Service de Gynécologie-Obstétrique, Colombes, France
- Université Paris 7–Denis Diderot, Paris, France
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356
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Abstract
Monocytes are the primary inflammatory cell type that infiltrates early atherosclerotic plaques. Their recruitment into plaques drives disease progression. Disease interventions that target monocytes could act at several points: alteration in the phenotype of circulating monocyte subpopulations; reduced recruitment of monocytes into plaques; alterations in the survival of monocyte-derived cells in atherosclerosis; and promotion of migratory egress from plaques to bring about resolution of the plaque inflammatory response. All of these points of intervention will be briefly discussed in this article.
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Affiliation(s)
- G J Randolph
- Department of Gene and Cell Medicine, and the Immunology Institute, Mount Sinai School of Medicine, New York, NY 10029, USA.
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357
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Weber B, Saurer L, Mueller C. Intestinal macrophages: differentiation and involvement in intestinal immunopathologies. Semin Immunopathol 2009; 31:171-84. [PMID: 19533135 DOI: 10.1007/s00281-009-0156-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Accepted: 05/11/2009] [Indexed: 12/11/2022]
Abstract
Intestinal macrophages, preferentially located in the subepithelial lamina propria, represent the largest pool of tissue macrophages in humans. As an adaptation to the local antigen- and bacteria-rich environment, intestinal macrophages exhibit several distinct phenotypic and functional characteristics. Notably, microbe-associated molecular pattern receptors, including the lipopolysaccharide (LPS) receptors CD14 and TLR4, and also the Fc receptors for IgA and IgG are absent on most intestinal macrophages under homeostatic conditions. Moreover, while macrophages in the intestinal mucosa are refractory to the induction of proinflammatory cytokine secretion, they still display potent phagocytic activity. These adaptations allow intestinal macrophages to comply with their main task, i.e., the efficient removal of microbes while maintaining local tissue homeostasis. In this paper, we review recent findings on the functional differentiation of monocyte subsets into distinct macrophage populations and on the phenotypic and functional adaptations that have evolved in intestinal macrophages in response to their antigen-rich environment. Furthermore, the involvement of intestinal macrophages in the pathogenesis of celiac disease and inflammatory bowel diseases is discussed.
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Affiliation(s)
- Benjamin Weber
- Division of Experimental Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
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358
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Genetic diversity of CX3CR1 gene and coronary artery disease: new insights through a meta-analysis. Atherosclerosis 2009; 207:8-15. [PMID: 19439304 DOI: 10.1016/j.atherosclerosis.2009.03.044] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Revised: 03/06/2009] [Accepted: 03/24/2009] [Indexed: 12/13/2022]
Abstract
A significant portion of current medical research is devoted to the pursuit of genetic markers that can be used to identify disease or predict susceptibility to disease. In such a quest many investigators hypothesized that genetic variations that alter signalling pathways involved in atherosclerosis affect susceptibility to coronary artery disease (CAD). Fractalkine (FKN) is a small cytokine involved in monocyte chemotaxis and activation. Two single nucleotide polymorphisms, V249I and T280M, have been identified in the receptor coding sequence of FKN. The polymorphisms alter ligand-receptor affinity and are believed to influence an individual's susceptibility to atherosclerosis. Several investigators have tested the latter hypothesis with inconsistent results. In order to clarify the effect of the two polymorphisms on susceptibility to CAD we performed a meta-analysis, using pooled data retrieved from seven case-control studies. In total, 2000 CAD patients and 2841 subjects without evidence of cardiovascular disease were included in the meta-analysis. The 280M allele was associated with a reduced risk for CAD in the heterozygous state. Consequently, this effect was attributed to the only 280M-containing haplotype: I(249)M(280). The latter haplotype was found to be significantly more frequent in the control population's gene pool. Although we do not believe that the retrieved odds ratios render the T280M polymorphism a candidate genetic marker for clinical applications, we do believe that the above genotype-phenotype interaction is indicative of the strong associations between FKN-induced pathways and CAD.
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359
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Soehnlein O, Weber C. Myeloid cells in atherosclerosis: initiators and decision shapers. Semin Immunopathol 2009; 31:35-47. [PMID: 19238385 DOI: 10.1007/s00281-009-0141-z] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Accepted: 02/10/2009] [Indexed: 12/24/2022]
Abstract
Chronic inflammation is the underlying pathophysiological mechanism of atherosclerosis. Prominent suspects being involved in atherosclerosis are lymphocytes, platelets, and endothelial cells. However, recent advances suggest a potent role for myeloid leukocytes, specifically monocyte subsets, polymorphonuclear leukocytes, and mast cells. These three cell types are not just rapidly recruited or already reside in the vascular wall but also initiate and perpetuate core mechanisms in plaque formation and destabilization. Dendritic cell subsets as well as endothelial and smooth muscle progenitor cells may further emerge as important regulators of atheroprogression. To stimulate further investigations about the contribution of these myeloid cells, we highlight the current mechanistic understanding by which these cells tune atherosclerosis.
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Affiliation(s)
- Oliver Soehnlein
- Institute for Molecular Cardiovascular Research, RWTH University Aachen, Pauwelsstr. 30, 52074, Aachen, Germany.
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