CC chemokine receptor 5 influences late-stage atherosclerosis

Members of the chemokine system, play a central role in inflammatory processes that underlie the pathogenesis of atherosclerosis and possibly, aortic valve sclerosis. Here we show that genetic inactivation of CC chemokine receptor 5 (CCR5) in the atherosclerosis-prone Apoe-/- mice (Apoe-/- Ccr5-/-) fed a normal chow or a high-fat diet (HFD) are protected against advanced atherosclerosis as well as age-associated aortic valve thickening (AAAVT)--a murine correlate of aortic valve sclerosis. Notably, human sclerotic valves contained CCR5+ cells. We confirm that Apoe-/- Ccr5-/- mice does not influence early-atherosclerotic stage. Adoptive transfer studies showed that the atheroprotective effect of CCR5 inactivation resided in the bone marrow compartment, but was not dependent on T-cells. The CCR5-null state was associated with phenotypes postulated to be atheroprotective such as reduced macrophage accumulation in the plaque, and lower circulating levels of IL-6 and MCP-5. The lack of CCR5 expression in Apoe-/- mice was also associated with higher numbers of endothelial progenitor cells (EPCs)--another postulated athero-protective factor. Compared with controls, carriers of a polymorphism in the Ccr5 gene that leads to the lack of CCR5 in the cell surface had an increased mean percentage of EPCs, but this difference did not reach statistical significance. Collectively, these findings underscore a critical role of CCR5 in age-associated cardiovascular diseases, and highlight that the effects of the chemokine system can be temporally constrained to distinct stages of these disease processes.     

The role of CC chemokine receptor 5 in antiviral immunity

The CC chemokine receptor CCR5 is an important coreceptor for human immunodeficiency virus (HIV), and there is a major thrust to develop anti-CCR5-based therapies for HIV-1. However, it is not known whether CCR5 is critical for a normal antiviral T-cell response. This study investigated the immune response to lymphocytic choriomeningitis virus in mice lacking CCR5 (CCR5(-/-) mice). This infection is a classical model for studying antiviral immunity, and influx of CCR5-expressing CD8(+) T cells and macrophages is essential for both virus control and associated immunopathology. Results showed that the virus-induced clonal expansion of antigen-specific T cells was augmented in CCR5(-/-) mice especially with regard to the CD4(+) subset. Despite absence of CCR5, intracerebral infection invariably resulted in lethal T cell-mediated meningitis, and quantitative and qualitative analysis of the inflammatory exudate cells did not reveal any significant differences between gene-targeted mice and wild-type controls. CCR5 was also found to be redundant regarding the ability to eliminate virus from internal organs. Using delayed-type hypersensitivity to evaluate CD8(+) T cell-mediated inflammation, no significant influence of CCR5 was found, not even when viral peptide was used as local trigger instead of live virus. Finally, long-term CD8(+) T cell-mediated immune surveillance was efficiently sustained in CCR5(-/-) mice. Taken together, these results indicate that expression of CCR5 is not critical for T cell-mediated antiviral immunity, and this molecule may therefore constitute a logic and safe target for anti-HIV therapies.     

Regulation of CC chemokine receptor 5 in hepatitis G virus infection

INTRODUCTION: Epidemiological data demonstrate an association between hepatitis G virus (HGV) co-infection and improved survival of HIV-positive individuals. However, the mechanism by which HGV affects progression of HIV disease remains unclear. As down-regulation of CC chemokine receptor 5 (CCR5) delays HIV progression, we investigated whether CCR5 expression is altered by exposure of lymphocytes to HGV proteins. METHODS: A cross-sectional analysis of CCR5 expression was carried out on CD4 and CD8 T lymphocytes of 11 HGV-positive and 12 HGV-negative persons, who were homozygous for the CCR5 wild-type gene. Binding of the HGV E2 protein to CD81 was analysed by flow cytometry. Lymphocytes were stimulated with immobilized HGV E2, anti-CD81 or serum proteins from HGV-infected subjects and changes in CCR5 expression and CC chemokine secretion were determined. RESULTS: We demonstrate that the HGV envelope protein E2 specifically binds to CD81 on T lymphocytes. This interaction induces a dose-dependent release of RANTES and down-regulation of CCR5 surface expression with concomitant intra-cellular accumulation of CCR5 proteins. This effect of HGV E2 on CCR5 expression was confirmed when lymphocytes were incubated with serum proteins from HGV-infected subjects. Finally, our cross-sectional analysis revealed CCR5 expression to be reduced by 53% and 36% on CD4 and CD8 lymphocytes of HGV-infected subjects, respectively (P < 0.01). CONCLUSIONS: Our results demonstrate that an interaction of HGV E2 with CD81 leads to increased RANTES secretion and decreased CCR5 surface expression. This mechanism might contribute to the delayed progression of HIV-infection in HGV-coinfected patients.     

CC chemokine receptor 5 polymorphism in Italian patients with giant cell arteritis

Abstract

The involvement of valgus hindfoot deformity in hallux valgus deformity was confirmed in a rheumatoid arthritis case with a destructive valgus hindfoot deformity. Correction of severe valgus, calcaneal lateral offset, and pronated foot deformity instantly normalized hallux valgus deformities postoperatively. Thus, careful hindfoot status evaluation is important when assessing forefoot deformity, including hallux valgus, in rheumatoid arthritis cases.     

Expression of human immunodeficiency virus coreceptors CXC chemokine receptor 4 and CC chemokine receptor 5 on monocytes is down-regulated during human endotoxemia

Lipopolysaccharide (LPS) can inhibit human immunodeficiency virus (HIV) infection in monocytes in vitro. To test the hypothesis that an LPS effect on CXC chemokine receptor 4 (CXCR4) and CC chemokine receptor 5 (CCR5), known coreceptors for HIV, contributes to this effect, 8 healthy men were intravenously injected with Escherichia coli LPS (4 ng/kg), and monocyte CXCR4 and CCR5 expression was monitored by fluorescence-activated cell sorter analysis. LPS induced a decrease in the fraction of peripheral blood monocytes expressing CXCR4 and CCR5, reaching a nadir after 2 h (both P<.001 vs. baseline). In whole blood in vitro, not only LPS but also lipoarabinomannan (a cell wall component of Mycobacterium tuberculosis) and lipoteichoic acid (a cell wall component of Staphylococcus aureus) down-regulated the expression of CXCR4 and CCR5 on monocytes (all P<.05). Exposure of monocytes to (myco)bacterial agents may render them relatively resistant to infection with HIV by an effect on HIV coreceptors.     

Absence of the association with CC chemokine receptor 5 polymorphism in polymyalgia rheumatica

OBJECTIVE: Elevated RANTES serum levels are present in polymyalgia rheumatica (PMR) patients with active disease. Chemokines may contribute to the inflammatory PMR process through their binding to CC chemokine receptor 5 (CCR5). The aim of this study was to examine if the 32 base pair deletion allele in CCR5 (CCR5 delta 32 allele) might be associated with PMR susceptibility and influence the disease outcome. METHODS: We enrolled 88 consecutive patients with PMR residing in the Reggio Emilia area (Italy) who had a follow-up duration of at least one year. As a control group we used 86 healthy blood donors from the same geographic area. The CCR5 genotype of all PMR patients and controls was studied by polymerase chain reaction amplification of the region which includes the 32 deletion (CCR5 delta 32). RANTES serum levels were measured by commercial ELISA kits in CCR5 delta 32 heterozygous and CCR5 homozygous PMR patients at diagnosis before starting corticosteroid therapy and again after 6 months of therapy, as well as in 28 healthy subjects over 50 years of age. RESULTS: Frequencies of the CCR5 and CCR5 delta 32 alleles in patients and controls did not differ significantly. Homozygosity for CCR5 delta 32 was not detected in PMR patients and was detected in only one of the controls. No significant differences were observed between the patients carrying the CCR5 delta 32 allele and those homozygous for the normal CCR5 allele when we compared sex, presence of distal synovitis and systemic signs and/or symptoms, initial and cumulative prednisone dose, duration of therapy, ESR at diagnosis, frequency of relapse/recurrence and RANTES serum levels at diagnosis and after 6 months of corticosteroids. CONCLUSION: These results indicate that the frequency of the 32 deletion of the CCR5 receptor was not significantly different between PMR patients and healthy controls, and this genotype does not appear to be associated with the susceptibility to or severity of PMR.     

Monocyte chemoattractant protein-2 (CC chemokine ligand 8) inhibits replication of human immunodeficiency virus type 1 via CC chemokine receptor 5

CC chemokine receptor 5 (CCR5) is a coreceptor for cellular entry of monocyte-tropic (R5) strains of human immunodeficiency virus (HIV) type 1, which has been implicated as the predominant phenotype of HIV in early infection. The CCR5 agonists macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, and RANTES (regulated on activation, normally T cell-expressed and -secreted) have been shown to block replication of R5 virus in vitro and have gained attention as potential antiviral factors. However, a few reports have suggested that other chemokines may also block R5 HIV-1, including monocyte chemoattractant protein (MCP)-2 (CC chemokine ligand 8). We demonstrate that MCP-2 specifically inhibits replication of R5 HIV-1 and that this activity is additive to that of RANTES. Furthermore, MCP-2 induces a robust, pertussis toxin-sensitive calcium flux in primary lymphocytes, and cross-desensitization studies indicate that MCP-2 acts via CCR5. These data confirm that MCP-2 is a ligand for CCR5 on CD4(+) lymphocytes and can specifically block R5 HIV-1.     

CCR5 expression and CC chemokine levels in idiopathic pulmonary fibrosis.

CC chemokines play an important role in the pathogenetic mechanisms of interstitial lung disease, while a downregulation of CC chemokine receptor (CCR)5 in the fibrotic stages of sarcoidosis has been observed. To evaluate the involvement of CC chemokines and the expression of CCR5 in idiopathic pulmonary fibrosis (IPF) and, more specifically, in usual interstitial pneumonia, 35 subjects were studied. CC chemokine ligand (CCL)2, CCL3 and CCL4 levels were measured in the bronchoalveolar lavage fluid (BALF) of 18 nonsmoker control subjects and 17 patients affected by IPF. CCR5 expression was evaluated in alveolar macrophages and lymphocytes. The BALF levels of all chemokines were significantly increased in IPF: median (range) CCL3 1.6 (1.0-11.1) versus 1.2 (0.0-3.8) pg x mL(-1); CCL4 6.2 (1.3-96.0) versus 3.4 (0.3-6.8) pg x mL(-1); and CCL2 60.1 (16.7-251.3) versus 4.6 (0.5-119.4) pg x mL(-1). CCL2 levels correlated negatively with the carbon monoxide diffusing capacity of the lung (D(L,CO)) and arterial oxygen tension. CCR5 expression was significantly reduced in lymphocytes from IPF compared with controls. The CC chemokines investigated are involved in the inflammatory mechanisms of idiopathic pulmonary fibrosis, and the results are in agreement with the hypothesis of a downregulation of the T-helper 1 immunological response in this disease.     

The CC chemokine 6Ckine binds the CXC chemokine receptor CXCR3

We cloned the mouse homologue of the chemokine receptor CXCR3, which is located in mouse chromosome X. We screened a large panel of chemokines for their ability to induce a calcium flux in mouse CXCR3-transfected cells and identified a new ligand for this receptor, the recently reported CC chemokine 6Ckine. This represents an example of a CC chemokine, which binds to a CXC chemokine receptor. Like other ligands of this receptor, 6Ckine has angiostatic properties. 6Ckine is known to chemoattract T cells. In line with this, CXCR3 is expressed preferentially in Th1 cells and in lymphoid organs of the IL-10^−/− mouse that develops chronic colitis. Its ability to attract T cells as well as its angiostatic properties suggest that 6Ckine may be an effective anti-tumor agent.     

趋化因子受体CCR7在心血管疾病中的研究进展

心血管疾病可能由免疫炎症反应引起,而趋化因子及其受体在免疫炎症反应中起着关键的作用,提示其与心血管疾病的发生、发展密切相关。本文就趋化因子受体CCR7在动脉粥样硬化、心肌病、心力衰竭以及心脏移植排斥反应等疾病的发病过程中的作用做一综述。     

Regulation of CC chemokine receptor 5 and CD4 expression and human immunodeficiency virus type 1 replication in human macrophages and microglia by T helper type 2 cytokines

Macrophages, microglia, and other mononuclear phagocytes serve as cellular reservoirs for viral persistence in patients with acquired immunodeficiency syndrome. To understand host mechanisms that affect human immunodeficiency virus type 1 (HIV-1) pathogenesis by modulating expression of coreceptors, cytokine regulation of CC chemokine receptor 5 (CCR5) and CD4 expression on monocytes, monocyte-derived macrophages (MDMs), and microglia was investigated. Interleukin (IL)-4 and IL-10 enhanced the entry and replication of HIV-1 in microglia through up-regulation of CD4 and CCR5 expression, respectively. IL-4 stimulated HIV-1 replication in MDMs but down-regulated CD4 and CCR5 expression and inhibited virus entry, whereas IL-10 had the opposite effects. Thus, mechanisms independent of CCR5 and CD4 expression levels are involved in pathways that regulate HIV-1 replication in MDMs. CCR5 up-regulation by IL-10 was associated with increased migration of microglia in response to macrophage inflammatory protein-1beta. These findings suggest that increased production of T helper type 2 cytokines in the later stages of disease can enhance virus entry and replication in mononuclear phagocytes and facilitate chemotactic migration.     

CC chemokine and CC chemokine receptor profiles in visceral and subcutaneous adipose tissue are altered in human obesity

BACKGROUND/AIMS: Obesity is associated with a low-grade inflammation, insulin resistance, and macrophage infiltration of adipose tissue. The role of CC chemokines and their respective receptors in human adipose tissue inflammation remains to be determined. METHODS: sc and visceral adipose tissue of obese patients (body mass index 53.1 +/- 11.3 kg/m(2)) compared with lean controls (body mass index 25.9 +/- 3.8 kg/m(2)) was analyzed for alterations in inflammatory gene expression. RESULTS: Macrophage infiltration was increased in sc and visceral adipose tissue of obese patients as determined by increased mRNA expression of a macrophage-specific marker (CD68) and by elevated macrophage infiltration. Gene expression of CC chemokines involved in monocyte chemotaxis (CCL2, CCL3, CCL5, CCL7, CCL8, and CCL11) and their receptors (CCR1, CCR2, CCR3, and CCR5) was higher in sc and visceral adipose tissue of obese patients. Serum concentrations of the inflammatory marker IL-6 and C-reactive protein were elevated in obese patients compared with lean controls. Obese patients revealed increased insulin resistance as assessed by the homeostasis model assessment of insulin resistance index and reduced plasma adiponectin concentrations. Adipose tissue expression of many CC chemokines and their receptors in the obese group positively correlated with CD68 expression. CONCLUSION: Up-regulation of the CC chemokines and their respective receptors in adipose tissue occurs in human obesity and is associated with increased systemic inflammation.     

Simvastatin modulates chemokine and chemokine receptor expression by geranylgeranyl isoprenoid pathway in human endothelial cells and macrophages

OBJECTIVE: Atherosclerosis is a chronic immuno-inflammatory disease involving the recruitment of monocytes and T lymphocytes to the vascular wall of arteries. Chemokines and their receptors, known to induce leukocyte migration, have recently been implicated in atherogenesis. Recent in vitro and in vivo studies have suggested that statins (3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors) have anti-inflammatory properties beyond their lipid-lowering effects. Thus, the aim of the present study was to investigate whether simvastatin reduces the expression of chemokines and chemokine receptors in two major cell types implicated in atherogenesis and to test isoprenoid intermediates involved in their regulation. METHODS AND RESULTS: We performed in vitro experiments on human vascular endothelial cells and human primary macrophages. First, we have shown by ELISA that 1 microM simvastatin significantly reduced MCP-1 in endothelial cells (ECs) and macrophages stimulated with TNF-alpha or IFN-gamma, respectively. Messenger RNA analysis revealed that expression of the chemokines MCP-1, MIP-1alpha and MIP-1beta, as well as the chemokine receptors CCR1, CCR2, CCR4 and CCR5, was decreased by simvastatin, both in ECs and macrophages. Furthermore, the statin effects were reversed by mevalonate and mimicked by the geranylgeranyl transferase inhibitor (GGTI), whereas the farnesyl transeferase inhibitor (FTI) had no effect. These results suggests that statins act via inhibition of the geranylgeranylation of proteins. CONCLUSIONS: Our results demonstrate that statins reduce chemokine and chemokine receptor expressions in human ECs and macrophages via inhibition of the geranylgeranylpyrophosphate pathway. Thus, our data provide further evidence that statins have anti-inflammatory properties beyond their lipid-lowering effects. These findings highlight specific novel therapeutic targets for cardiovascular diseases to reduce inflammation mediated by chemokines and their receptors.     

Granulocyte macrophage colony-stimulating factor and interleukin-3 regulate chemokine and chemokine receptor expression in bone marrow macrophages

The beta-chemokine macrophage inflammatory protein-1 alpha (MIP-1alpha) and its associated receptors are involved in the regulation of pro-inflammatory and haemopoietic processes. This study was designed to investigate regulation of expression MIP-1alpha and its receptors by other haemopoietic cytokines. Murine bone marrow macrophages (BMM) were treated with or without GM-CSF or IL-3 and expression of MIP-1alpha, other chemokines and their receptors examined by Northern blotting. Receptor levels were also examined using Scatchard analysis and functional tests. Treatment of BMM with GM-CSF revealed a striking increase in MIP-1alpha mRNA levels, relative to untreated cells with a corresponding increase in MIP-1alpha protein. A similar increase in mRNA levels was found when BMM were treated with IL-3. An increase in the expression of three other beta-chemokines namely MIP-1beta, MCP-1 and MCP-3, was also found following treatment with GM-CSF or IL-3. We have additionally examined the expression of the known beta-chemokine receptors in BMM and observed an increase in CCR1 mRNA levels following treatment with GM-CSF and IL-3, but no change was seen in the level of CCR5 expression. The increase in CCR1 expression was reflected in an increase in the number of cell surface receptors for MIP-1alpha on the GM-CSF treated BMM and in an enhanced response of the GM-CSF treated BMM to CCR1 ligands. These data suggest that GM-CSF and IL-3 may be involved in mechanisms regulating expression levels of MIP-1alpha and its receptors.     

Antibodies to varicella-zoster virus in blood donors with genetic variance in CC chemokine receptor 5

Carriers of a 32 bp deletion (Delta32) allele of the CC chemokine receptor 5 (CCR5) gene are reported to be more likely to lack antibodies to varicella-zoster virus than CCR5 wild-type individuals. To find out whether CCR5-Delta32 is associated with the seroprevalence of varicella-zoster virus infection, we tested blood donors with different CCR5-Delta32 genotypes for varicella-zoster virus IgG. Antibody to varicella-zoster virus was present in 209 (99.5%) of 210 CCR5-Delta32 carriers and exactly the same proportion of CCR5 wild-type individuals (209 of 210). We have therefore found no evidence that the CCR5-Delta32 allele is associated with decreased seroprevalence of varicella-zoster virus infection.     

Clinical and prognostic significance of CC chemokine receptor type 8 protein expression in gastrointestinal stromal tumors

BACKGROUND Gastrointestinal stromal tumors(GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract. Surgical resection and tyrosine kinase inhibitors are defined as the main treatments but cannot cure patients with advanced GIST, which eventually develops into recurrence and acquired drug resistance. Therefore, it is necessary to identify prognostic biomarkers and new therapeutic targets for GISTs. CC chemokine receptor type 8(CCR8) protein participates in regulation of immune responses. Recent studies on CCR8 in nonsmall cell lung cancer and colorectal cancer showed that it was highly expressed in tumor-infiltrating regulatory T cells and correlated with a poor prognosis.AIM To detect CCR8 expression in GIST tissues and analyze its relationships with clinicopathological features and prognosis in patients with GISTs.METHODS Tissue samples were used for the tissue microarrays construction. The microarrays were then subjected to immunohistochemical analyses to detect CCR8 expression. Next, Kaplan–Meier analysis was utilized to calculate the survival rate of patients with complete follow-up data, and the potential prognostic value of CCR8 was evaluated by Cox regression analysis. Finally, a Gene Ontology/Kyoto Encyclopedia of Genes and Genomes single-gene enrichment chart of CCR8 was constructed using the STRING database.RESULTS CCR8-positive signals were detected as brown or brown-yellow particles by immunohistochemistry located in the cytoplasm. Among 125 tissue samples, 74 had CCR8 high expression and 51 had low or negative expression. Statistical analyses suggested CCR8 was significantly correlated with tumor size, mitotic index, AFIP-Miettinen risk classification and tumor location. Kaplan–Meier and multivariate analyses showed that patients with low or negative CCR8 expression, mitotic index 5/high-power fields(HPF) and tumor diameter 5 cm had a better prognosis. Based on the STRING database, CCR8 was significantly enriched in biological processes such as tumor immunity, T lymphocyte chemotaxis, migration and pathways like the nuclear factor-κB and tumor necrosis factor pathways as well as intestinal immune regulation networks.CONCLUSION CCR8 is a prognostic biomarker for malignant potential of GISTs, with high expression correlated with malignancy and poor prognosis.     

Human cytomegalovirus enhances chemokine production by lipopolysaccharide-stimulated lamina propria macrophages

To elucidate the role of mucosal macrophages in intestinal human cytomegalovirus (HCMV) disease, primary lamina propria macrophages (LPM) were isolated from normal human jejunum, infected with HCMV, and studied for their cytokine responses. HCMV infection of LPM was confirmed by the presence of HCMV IE72 (UL123), pp65 (UL83), and glycoprotein B (UL55) proteins, which were detected by immunofluorescence, beginning at postinfection (pi) day 3, and were sustained through pi day 12 in 0.1%-0.5% of LPM. The late protein pp28 (UL99) was also detected up to pi day 12, consistent with productive infection. HCMV infection in LPM was characterized by quantitative competitive polymerase chain reaction, with maximum levels of HCMV DNA detected at pi day 7. HCMV infection of the LPM augmented lipopolysaccharide-inducible chemokine (interleukin [IL]-8 and macrophage inflammatory protein-1alpha) and cytokine (IL-6) production. These findings suggest that mucosal macrophages, via enhanced mediator production, play an important role in intestinal inflammation associated with HCMV infection.