Showing papers on "Chemokine receptor CCR5 published in 2009"

Chemokine Expression in Melanoma Metastases Associated with CD8+ T-Cell Recruitment

Abstract: Despite the frequent detection of circulating tumor antigen-specific T cells, either spontaneously or following active immunization or adoptive transfer, immune-mediated cancer regression occurs only in the minority of patients. One theoretical rate-limiting step is whether effector T cells successfully migrate into metastatic tumor sites. Affymetrix gene expression profiling done on a series of metastatic melanoma biopsies revealed a major segregation of samples based on the presence or absence of T-cell-associated transcripts. The presence of lymphocytes correlated with the expression of defined chemokine genes. A subset of six chemokines (CCL2, CCL3, CCL4, CCL5, CXCL9, and CXCL10) was confirmed by protein array and/or quantitative reverse transcription-PCR to be preferentially expressed in tumors that contained T cells. Corresponding chemokine receptors were found to be up-regulated on human CD8(+) effector T cells, and transwell migration assays confirmed the ability of each of these chemokines to promote migration of CD8(+) effector cells in vitro. Screening by chemokine protein array identified a subset of melanoma cell lines that produced a similar broad array of chemokines. These melanoma cells more effectively recruited human CD8(+) effector T cells when implanted as xenografts in nonobese diabetic/severe combined immunodeficient mice in vivo. Chemokine blockade with specific antibodies inhibited migration of CD8(+) T cells. Our results suggest that lack of critical chemokines in a subset of melanoma metastases may limit the migration of activated T cells, which in turn could limit the effectiveness of antitumor immunity.

Persistence of HIV-1 receptor–positive cells after HSV-2 reactivation is a potential mechanism for increased HIV-1 acquisition

Abstract: Infection with HSV-2 increases the likelihood of HIV acquisition, but suppression of HSV-2 reactivation with antiviral drugs does not seem to reduce the acquisition of HIV. Laurence Corey and colleagues provide a potential mechanism underlying this observation, showing that even after acyclovir treatment for the HSV-2 infection, many inflammatory and immune cells possessing the receptors required for HIV infection persist in the mucosa, making the initial 'spark' of infection more likely. To explore the mechanism by which herpes simplex virus (HSV)-2 infection is related to HIV-1 acquisition, we conducted in situ analysis of the cellular infiltrate from sequential biopsies of HSV-2 lesions from patients on and off antiviral therapy. CD4+ and CD8+ T cells and a mixed population of plasmacytoid and myeloid dendritic cells (DCs), including cells expressing the C-type lectin receptor DC-SIGN, persisted at sites of HSV-2 reactivation for months after healing, even with daily antiviral therapy. The CD4+ T cells that persisted reacted to HSV-2 antigen, were enriched for expression of the chemokine receptor CCR5, and were contiguous to DCs expressing the interleukin-3 receptor CD123 or DC-SIGN. Ex vivo infection with a CCR5-tropic strain of HIV-1 revealed greater concentrations of integrated HIV-1 DNA in cells derived from healed genital lesion biopsies than in cells from control skin biopsies. The persistence and enrichment of HIV receptor–positive inflammatory cells in the genitalia help explain the inability of anti–HSV-2 therapy to reduce HIV acquisition.

The Duffy antigen receptor for chemokines transports chemokines and supports their promigratory activity

Abstract: The Duffy antigen receptor for chemokines (DARC) belongs to a family of ‘silent’ heptahelical chemokine receptors that do not couple to G proteins and fail to transmit measurable intracellular signals. DARC binds most inflammatory chemokines and is prominently expressed on venular endothelial cells, where its function has remained contentious. Here we show that DARC, like other silent receptors, internalized chemokines but did not effectively scavenge them. Instead, DARC mediated chemokine transcytosis, which led to apical retention of intact chemokines and more leukocyte migration across monolayers expressing DARC. Mice overexpressing DARC on blood vessel endothelium had enhanced chemokine-induced leukocyte extravasation and contact-hypersensitivity reactions. Thus, interactions of chemokines with DARC support their activity on apposing leukocytes in vitro and in vivo.

D6 and the atypical chemokine receptor family: novel regulators of immune and inflammatory processes.

Abstract: Chemokines are key regulators of leukocyte migration and play important roles in a number of physiological and pathological immune and inflammatory contexts. In addition to the classical signalling chemokine receptors there has emerged, recently, a new subclass of atypical chemokine receptors. This subfamily is characterised by an apparent lack of signalling and, in some cases, by an ability to internalise and degrade chemokine ligands. This review describes the family of atypical chemokine receptors with particular emphasis on the D6 receptor. The in vitro and in vivo biology of D6 is described, which indicates that D6 is active as a scavenger of inflammatory CC-chemokines and appears to play essential roles in the regulation of inflammatory responses.

The chemokine CCL20 and its receptor CCR6 in human malignancy with focus on colorectal cancer.

Abstract: Chemokines are a superfamily of small chemotactic cytokines, which interact with their G-protein-coupled receptors. These interactions regulate multiple physiological functions, particularly tissue architecture and compartment-specific migration of white blood cells. It has been found that the chemokine/chemokine receptor system has been utilized by cancer cells for migration and metastasis. The chemokine receptor CCR6 is expressed in colorectal cancer and several other cancer types, and stimulation by its physiological chemokine ligand CCL20 has been reported to promote cancer cell proliferation and migration in vitro. Moreover, CCR6/CCL20 interactions apparently play a role in organ selective liver metastasis of colorectal cancer. Here, we review the literature on expression patterns of CCL20 and CCR6 and their physiological interactions as well as the currently presumed role of CCR6 and CCL20 in the formation of colorectal cancer liver metastasis, providing a potential basis for novel treatment strategies.

Chemokine receptor antagonists: Part 1.

Abstract: Background: Chemokines were originally defined as host defense proteins, however, their biological role goes well beyond this simple description of their function as immune cell chemoattractants, a...

GB virus type C interactions with HIV: the role of envelope glycoproteins.

Abstract: GB virus C/hepatitis G virus (GBV-C/HGV) is the most closely related human virus to hepatitis C virus (HCV). GBV-C is lymphotropic and not associated with any known disease, although it is associated with improved survival in HIV-infected individuals. In peripheral blood mononuclear cells, GBV-C induces the release of soluble ligands for HIV entry receptors (RANTES, MIP-1a, MIP-1b and SDF-1), suggesting that GBV-C may interact with lymphocytes to induce a chemokine and/or cytokine milieu that is inhibitory to HIV infection. Expression of GBV-C envelope glycoprotein E2 in CD4+ T cells or addition of recombinant E2 to CD4 cells recapitulates the HIV inhibition seen with GBV-C infection. Like HCV E2, GBV-C E2 is predicted to be post-translationally processed in the endoplasmic reticulum and is involved with cell binding. The C-termini of GBV-C E1 and E2 proteins contain predicted transmembrane domains sharing features with HCV TM domains. To date, cellular receptor(s) for GBV-C E2 have not been identified. GBV-C E2-mediated HIV inhibition is dose-dependent and HIV replication is blocked at the binding and/or entry step. In addition, a putative GBV-C E2 fusion peptide interferes with HIV gp41 peptide oligomerization required for HIV-1 fusion, further suggesting that GBV-C E2 may inhibit HIV entry. Additional work is needed to identify the GBV-C E2 cellular receptor, characterize GBV-C E2 domains responsible for HIV inhibition, and to examine GBV-C E2-mediated fusion in the context of the entire envelope protein or viral-particles. Understanding the mechanisms of action may identify novel approaches to HIV therapy.

Chemokine receptor expression and functional effects of chemokines on B cells: implication in the pathogenesis of rheumatoid arthritis

Abstract: Accumulation of B cells in the rheumatoid arthritis (RA) synovium has been reported, and it has been thought that these cells might contribute to the pathogenesis of RA by antigen presentation, autoantibody production, and/or inflammatory cytokine production. Chemokines could enhance the accumulation of B cells in the synovium. The aims of this study were to determine chemokine receptor expression by B cells both in the peripheral blood of normal donors and subjects with RA, and at the inflammatory site in RA, and the effects of chemokines on B cell activation. Cell surface molecule expression was analyzed by flow cytometry. Cellular migration was assessed using chemotaxis chambers. Cellular proliferation was examined by 3H-thymidine incorporation. Tumor necrosis factor (TNF) production was assayed by enzyme-linked immunosorbent assay. Significant numbers of peripheral blood B cells of healthy donors and subjects with RA expressed CC chemokine receptor (CCR)5 and CXCR3, and most B cells expressed CCR6, CCR7, CXCR4 and CXCR5. CCR5 expression was more frequent on CD27+ than CD27- peripheral blood B cells of healthy donors and RA. Synovial B cells more frequently expressed CCR5, but less often expressed CCR6, CCR7 and CXCR5 compared to peripheral blood in RA. Further functional analyses were performed on peripheral blood B cells from healthy donors. Migration of peripheral blood B cells, especially CD27+ B cells, was enhanced by CC chemokine ligand (CCL)20, CCL19, CCL21 and CXCL12. All four chemokines alone induced B cell proliferation; with CCL21 being the most effective. CCL21 also enhanced the proliferation of anti-immunoglobulin (Ig)M-stimulated B cells and blockade of CCR7 inhibited this effect. CCL20, CCL21 and CXCL12 enhanced TNF production by anti-IgM mAb-stimulated B cells. Finally, stimulation with CXCL12, but not CCL20, CCL19 and CCL21, enhanced inducible costimulator-ligand (ICOSL) expression by peripheral blood B cells of healthy donors and RA, but did not increase B cell-activating factor receptor or transmembrane activator and CAML-interactor. The data suggest that CCR5, CCR6, CCR7, CXCR3, CXCR4 and CXCR5 may be important for the B cell migration into the synovium of RA patients, and also their local proliferation, cytokine production and ICOSL expression in the synovium.

Expression of chemokines and chemokine receptors in human colon cancer.

Abstract: Human colorectal cancer (CRC), the second largest cause of tumor-related death in Western countries, represents a paradigm for the now well-established connections between inflammation and cancer. In this study, we investigated which inflammatory mediators are mostly expressed in the microenvironment of human CRC. The RNA profile of a large panel of inflammatory genes, in particular chemokines and chemokine receptors, was analyzed in eight surgical tumor samples and in paired normal tissues from CRC patients. We employed an "inflammatory gene card" (TaqMan Low Density Array by Applied Biosystem), designed by our group, containing probes for 24 chemokines and 17 chemokine receptors. Several chemokines were strongly upregulated in the tumor microenvironment, most frequently CCL4 and CCL5, chemotactic for monocytes/macrophages and T cells, and the corresponding receptors CCR1 and CCR5; the angiogenic chemokines CXCL1 and CXCL8, and the receptor CXCR2. The antiangiogenic chemokines CXCL9 and CXCL10 were also expressed, but in the absence of the receptor CXCR3. Selected results have been confirmed in a larger number of samples. The levels of mRNA CXCL8 were significantly associated with the levels of osteopontin, a matrix-associated protein that shares with chemokines important functions such as induction of cell migration and survival, and modulation of the neoangiogenesis. Overall these results could be helpful to identify the most relevant inflammatory pathways present in CRC tumors and to build a solid rationale for future therapeutic interventions based on anti-inflammatory strategies.

Overexpression of CXC chemokine receptors is required for the superior glioma-tracking property of umbilical cord blood-derived mesenchymal stem cells.

Abstract: Our observations indicate that umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) have a strong migration capacity toward the human glioma cell line, U-87 MG, LN18, U138, and U251, when compared to several other cancer cell lines. In order to identify soluble factors that function to attract UCB-MSCs, we used cytokine antibody arrays to screen changed cytokines in conditioned media from U-87 MG cells. Among these, interleukin-8 (IL-8) and growth-related oncogene (GRO-alpha) enhanced UCB-MSC migration. Furthermore, antibodies treatment against the IL-8 receptors reduced these migration events and overexpression of IL-8 in cells with lower level of IL-8 such as A549 could induce UCB-MSC migration. Since we found that the capacity of UCB-MSC migration is much higher than that of bone marrow-derived MSCs (BM-MSCs) toward either U-87 MG cells or recombinant IL-8, we compared the levels of the IL-8 receptor, CXC chemokine receptor 1 (CXCR1) and CXCR2 between two kinds of MSCs by RT-PCR and immunostaining. Expression levels of two receptors were much higher in UCB-MSCs than in BM-MSCs. These data suggest that higher levels of two IL-8 receptors could influence downstream signaling events affecting superior UCB-MSC migration toward the glioma cells.

Morphine enhances Tat-induced activation in murine microglia.

Abstract: There is increasing evidence that opiates accelerate the pathogenesis and progression of acquired immunodeficiency syndrome (AIDS), as well as the incidence of human immunodeficiency virus (HIV) encephalitis (HIVE), a condition characterized by inflammation, leukocyte infiltration, and microglial activation. The mechanisms, by which the HIV-1 transactivating protein Tat and opioids exacerbate microglial activation, however, are not fully understood. In the current study, we explored the effects of morphine and HIV-1 Tat(1-72) on the activation of mouse BV-2 microglial cells and primary mouse microglia. Both morphine and Tat exposure caused up-regulation of the chemokine receptor CCR5, an effect blocked by the opioid receptor antagonist naltrexone. Morphine in combination with Tat also induced morphological changes in the BV-2 microglia from a quiescent to an activated morphology, with a dramatic increase in the expression of the microglial activation marker CD11b, as compared with cells exposed to either agent alone. In addition, the mRNA expression of inducible nitric oxide synthase (iNOS), CD40 ligand, Interferon-gamma-inducible protein 10 (IP-10), and the proinflammatory cytokines tumor necrosis factor alpha (TNFalpha), interleukin (IL)-1beta, and IL-6, which were elevated with Tat alone, were dramatically enhanced with Tat in the presence of morphine. In summary, these findings shed light on the cooperative effects of morphine and HIV-1 Tat on both microglial activation and HIV coreceptor up-regulation, effects that could result in exacerbated neuropathogenesis.

Intratumoral Induction of CD103 Triggers Tumor-Specific CTL Function and CCR5-Dependent T-Cell Retention

Abstract: We have reported previously that the interaction of alpha(E)(CD103)beta(7) integrin, expressed on a CD8(+) tumor-infiltrating lymphocyte (TIL) clone but not on a peripheral blood lymphocyte (PBL) counterpart, with the epithelial marker E-cadherin on human lung tumor cells plays a crucial role in T-cell receptor-mediated cytotoxicity. We show here that both TIL and PBL clones are able to migrate toward autologous tumor cells and that chemokine receptor CCR5 is involved in this process. Adoptive transfer of the PBL clone in the cognate tumor engrafted in nonobese diabetic/severe combined immunodeficient mice and subsequent coengagement of T-cell receptor and transforming growth factor-beta1 receptor triggers CD103 expression on T-cell surface resulting in strong potentiation of antitumor lytic function. Moreover, interaction of alpha(E)beta(7) integrin with E-cadherin, but not lymphocyte function-associated antigen-1 with intercellular adhesion molecule-1, promotes CCR5 recruitment at the immunologic synapse formed between TIL and tumor cells, leading to inhibition of T-cell sensitivity to CCL5 chemotactic gradient. These results provide evidence for a role of tumor microenvironment, namely MHC class I-restricted antigen presentation and transforming growth factor-beta1 secretion, in regulating the effector phase of tumor-specific CTL response. They also suggest a unique role of CD103 in T-cell retention at the tumor site by a CCR5-dependent mechanism.

CXCR4 chemokine receptor antagonists: perspectives in SCLC.

Abstract: Small-cell lung cancer (SCLC) is a particularly aggressive form of lung cancer characterized by early and widespread metastases and the ability to rapidly develop resistance against chemotherapeuti...

Protection of Stem Cell-Derived Lymphocytes in a Primate AIDS Gene Therapy Model after In Vivo Selection

Abstract: Background: There is currently no effective AIDS vaccine, emphasizing the importance of developing alternative therapies. Recently, a patient was successfully transplanted with allogeneic, naturally resistant CCR5-negative (CCR5 delta 32) cells, setting the stage for transplantation of naturally resistant, or genetically modified stem cells as a viable therapy for AIDS. Hematopoietic stem cell (HSC) gene therapy using vectors that express various anti-HIV transgenes has also been attempted in clinical trials, but inefficient gene transfer in these studies has severely limited the potential of this approach. Here we evaluated HSC gene transfer of an anti-HIV vector in the pigtailed macaque (Macaca nemestrina) model, which closely models human transplantation. Methods and Findings: We used lentiviral vectors that inhibited both HIV-1 and simian immunodeficiency virus (SIV)/HIV-1 (SHIV) chimera virus infection, and also expressed a P140K mutant methylguanine methyltransferase (MGMT) transgene to select gene-modified cells by adding chemotherapy drugs. Following transplantation and MGMT-mediated selection we demonstrated transgene expression in over 7% of stem-cell derived lymphocytes. The high marking levels allowed us to demonstrate protection from SHIV in lymphocytes derived from gene-modified macaque long-term repopulating cells that expressed an HIV-1 fusion inhibitor. We observed a statistically significant 4-fold increase of gene-modified cells after challenge of lymphocytes from one macaque that received stem cells transduced with an anti-HIV vector (p<0.02, Student's t-test), but not in lymphocytes from a macaque that received a control vector. We also established a competitive repopulation assay in a second macaque for preclinical testing of promising anti-HIV vectors. The vectors we used were HIV-based and thus efficiently transduce human cells, and the transgenes we used target HIV-1 genes that are also in SHIV, so our findings can be rapidly translated to the clinic. Conclusions: Here we demonstrate the ability to select protected HSC-derived lymphocytes in vivo in a clinically relevant nonhuman primate model of HIV/SHIV infection. This approach can now be evaluated in human clinical trials in AIDS lymphoma patients. In this patient setting, chemotherapy would not only kill malignant cells, but would also increase the number of MGMTP140K-expressing HIV-resistant cells. This approach should allow for high levels of HIV-protected cells in AIDS patients to evaluate AIDS gene therapy.

Human immunodeficiency virus type 1 V1-to-V5 envelope variants from the chronic phase of infection use CCR5 and fuse more efficiently than those from early after infection.

Abstract: Human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein modifications over the course of infection have been associated with coreceptor switching and antibody neutralization resistance, but the effect of the changes on replication and host cell receptor usage remains unclear. To examine this question, unique early- and chronic-stage infection envelope V1-to V5 (V1-V5) segments from eight HIV-1 subtype A-infected subjects were incorporated into an isogenic background to construct replication-competent recombinant viruses. In all subjects, viruses with chronic-infection V1-V5 segments showed greater replication capacity than those with early-infection V1-V5 domains in cell lines with high levels of both the CD4 and the CCR5 receptors. Viruses with chronic-infection V1-V5s demonstrated a significantly increased ability to replicate in cells with low CCR5 receptor levels and greater resistance to CCR5 receptor and fusion inhibitors compared to those with early-infection V1-V5 segments. These properties were associated with sequence changes in the envelope V1-V3 segments. Viruses with the envelope segments from the two infection time points showed no significant difference in their ability to infect cells with low CD4 receptor densities, in their sensitivity to soluble CD4, or in their replication capacity in monocyte-derived macrophages. Our results suggest that envelope changes, primarily in the V1-V3 domains, increase both the ability to use the CCR5 receptor and fusion kinetics. Thus, envelope modifications over time within a host potentially enhance replication capacity.

Differential Expression of RDC1/CXCR7 in the Human Placenta

Abstract: Chemokine receptor expression by human trophoblast and other placental cells have important implications for understanding the regulation of placental growth, development, and their role in maternofetal HIV transmission. CXCR7, now a deorphanized G protein coupled receptor that has been recently shown to bind to the ligands ITAC and CXCL12 has been proposed to act as a co-receptor for HIV-1, HIV-2, and SIV strains. The differential expression of CXCR7 in the human placenta is not yet reported. The expression of CXCR7 was studied in 45 different human placental tissues, of which 20 were from early placental tissues (8–10 week old) obtained from medically terminated pregnancies and 25 were placenta from normal term deliveries. Immunohistochemistry and RT-PCR analysis revealed a greater expression of CXCR7 in term human placenta as compared to the early stage. This was further confirmed by real-time PCR. Our study reveals, for the first time, the differential expression of CXCR7 in early (8–10 weeks) and term human placenta. The precise role of CXCR7 in the human placenta needs to be determined. HIV vertical transmission is reported to occur mainly during the end stages of pregnancy. Our finding of increased CXCR7 expression in the term human placenta therefore warrants future studies to assess its role in the vertical transmission of HIV-1.

Pertussis Toxin Signals through the TCR to Initiate Cross-Desensitization of the Chemokine Receptor CXCR4

Abstract: Pertussis toxin (PTx) has been shown to exert a variety of effects on immune cells independent of its ability to ADP-ribosylate G proteins. Of these effects, the binding subunit of PTx (PTxB) has been shown to block signaling via the chemokine receptor CCR5, but the mechanism involved in this process is unknown. Here, we show that PTxB causes desensitization of a related chemokine receptor, CXCR4, and explore the mechanism by which this occurs. CXCR4 is the receptor for the chemokine stromal cell-derived factor 1α (SDF-1α) and elicits a number of biological effects, including stimulation of T cell migration. PTxB treatment causes a decrease in CXCR4 surface expression, inhibits G protein-associated signaling, and blocks SDF-1α-mediated chemotaxis. We show that PTxB mediates these effects by activating the TCR signaling network, as the effects are dependent on TCR and ZAP70 expression. Additionally, the activation of the TCR with anti-CD3 mAb elicits a similar set of effects on CXCR4 activity, supporting the idea that TCR signaling leads to cross-desensitization of CXCR4. The inhibition of CXCR4 by PTxB is rapid and transient; however, the catalytic activity of PTx prevents CXCR4 signaling in the long term. Thus, the effects of PTx holotoxin on CXCR4 signaling can be divided into two phases: short term by the B subunit, and long term by the catalytic subunit. These data suggest that TCR crosstalk with CXCR4 is likely a normal cellular process that leads to cross-desensitization, which is exploited by the B subunit of PTx.

Human Cytomegalovirus US28: a functionally selective chemokine binding receptor.

Abstract: Chemokines are small cytokines that are part of a large family of molecules that bind to G-protein coupled receptors, which, as a family, are the most widely targeted group of molecules in the treatment of disease. Chemokines are critical for recruiting and activating the cells of the immune system during inflammation especially during viral infections. However, a number of viruses including the large herpes virus human cytomegalovirus (HCMV) encode mechanisms to impede the effects of chemokines or has gained the ability to use these molecules to its own advantage. The Human Cytomegalovirus (HCMV)-encoded chemokine receptor US28 is the best characterized of the four unique chemokine receptor-like molecules found in the HCMV genome. US28 has been studied as an important virulence factor for HCMVmediated vascular disease and, more recently, in models of HCMV-associated malignancy. US28 is a rare multichemokine family binding receptor with the ability to bind ligands from two distinct chemokine classes. Ligand binding to US28 activates cell-type and ligand-specific signaling pathways leading to cellular migration, which is an important example of receptor functional selectivity. Additionally, US28 has been demonstrated to constitutively activate phospholipase C (PLC) and NF-κB signaling pathways. Understanding the structure/function relationships between US28, its ligands and intracellular signaling molecules will provide essential clues for effective pharmacological targeting of this multifunctional chemokine receptor.

M- and T-tropic HIVs promote apoptosis in rat neurons.

Abstract: Neuronal loss, reactive astrocytes, and other abnormalities are seen in the brain of individuals with acquired immune deficiency syndrome-associated Dementia Complex (ADC). Human immunodeficiency virus-1 (HIV-1) is believed to be the main agent causing ADC. However, little is known about the molecular and cellular mechanisms of HIV-1 neurotoxicity considering that HIV-1 does not infect post-mitotic neurons and that viral load does not necessarily correlate with ADC. Various viral proteins, such as the envelope protein gp120 and the transcription activator Tat, have been shown to induce neuronal apoptosis through direct and indirect mechanisms both in vitro and in vivo. Progeny HIV-1 virions can also cause neuronal death. However, it has not been fully established yet whether HIV-1 promotes neuronal apoptosis by a direct mechanism. To explore the neurotoxic effect of HIV-1, we exposed rat cerebellar granule cells and cortical neurons in culture to two different strains of HIV-1, IIIB and BaL, T- and M-tropic strains that utilize CXCR4 and CCR5 coreceptors, respectively, to infect cells. We observed that both viruses elicit a time-dependent apoptotic cell death in these cultures without inducing a productive infection as determined by the absence of the core protein of HIV-1, p24, in cell lysates. Instead, neurons were gp120 positive, suggesting that the envelope protein is shed by the virus and then subsequently internalized by neurons. The CXCR4 receptor antagonist AMD3100 or the CCR5 receptor inhibitor d-Ala-peptide T-amide blocked HIV IIIB and HIV Bal neurotoxicity, respectively. In contrast, the N-methyl-d-aspartate receptor blocker MK801 failed to protect neurons from HIV-mediated apoptosis, suggesting that HIV-1 neurotoxicity can be initiated by the viral protein gp120 binding to neuronal chemokine receptors.

Negative association of the chemokine receptor CCR5 d32 polymorphism with systemic inflammatory response, extra-articular symptoms and joint erosion in rheumatoid arthritis

Abstract: Chemokines and their receptors control immune cell migration during infections as well as in autoimmune responses. A 32 bp deletion in the gene of the chemokine receptor CCR5 confers protection against HIV infection, but has also been reported to decrease susceptibility to rheumatoid arthritis (RA). The influence of this deletion variant on the clinical course of this autoimmune disease was investigated. Genotyping for CCR5d32 was performed by PCR and subsequent electrophoretic fragment length determination. For the clinical analysis, the following extra-articular manifestations of RA were documented by the rheumatologist following the patient: presence of rheumatoid nodules, major organ vasculitis, pulmonary fibrosis, serositis or a Raynaud's syndrome. All documented CRP levels were analyzed retrospectively, and the last available hand and feet radiographs were analyzed with regards to the presence or absence of erosive disease. Analysis of the CCR5 polymorphism in 503 RA patients and in 459 age-matched healthy controls revealed a significantly decreased disease susceptibility for carriers of the CCR5d32 deletion (Odds ratio 0.67, P = 0.0437). Within the RA patient cohort, CCR5d32 was significantly less frequent in patients with extra-articular manifestations compared with those with limited, articular disease (13.2% versus 22.8%, P = 0.0374). In addition, the deletion was associated with significantly lower average CRP levels over time (median 8.85 vs. median 14.1, P = 0.0041) and had a protective effect against the development of erosive disease (OR = 0.40, P = 0.0047). Intriguingly, homozygosity for the RA associated DNASE2 -1066 G allele had an additive effect on the disease susceptibility conferred by the wt allele of CCR5 (OR = 2.24, P = 0.0051 for carrier of both RA associated alleles) The presence of CCR5d32 significantly influenced disease susceptibility to and clinical course of RA in a German study population. The protective effect of this deletion, which has been described to lead to a decreased receptor expression in heterozygous patients, underlines the importance of chemokines in the pathogenesis of RA.

Enhancement of Chemokine Expression by Interferon Beta Therapy in Patients With Multiple Sclerosis

Abstract: Background Interferon beta has been approved for the treatment of multiple sclerosis (MS). It is believed that immunomodulatory rather than antiviral activity of interferon beta is responsible for disease amelioration. The impact of interferon beta on the chemoattraction of immune cells has not been fully addressed. Objective To address the influence of interferon beta on the expression of chemokines and their receptors in a standardized setting. Design The expression of 14 chemokines and 14 chemokine receptor genes was determined by quantitative real-time polymerase chain reaction from fresh blood samples. Setting Outpatient units in Germany. Patients Untreated and interferon beta–treated patients with MS who tested positive and negative for neutralizing antibodies (NABs) were recruited from August 24, 2006, through December 15, 2006, for the initial study and from March 12, 2007, through April 2, 2007, for the validation study. Main Outcome Measures Gene expression and serum chemokine protein levels. Results CCL1, CCL2, CCL7, CXCL10, CXCL11, and CCR1 gene expression was strongly upregulated in interferon beta–treated, NAB-negative MS patients. In contrast, gene expression in interferon beta–treated, NAB-positive MS patients did not differ from untreated control donor individuals. Antibody titers inversely correlated with chemokine and chemokine receptor gene expression. Accordingly, serum chemokine protein levels of interferon beta–treated, NAB-negative MS patients were significantly higher than in untreated or interferon beta–treated, NAB-positive MS patients. Conclusions We demonstrate that interferon beta strongly upregulates a set of chemokines and CCR1 in peripheral immune cells. The peripheral upregulation of these chemokines may reduce the chemoattraction of immune cells to the central nervous system and thus add to the therapeutic effects of interferon beta. Published online August 10, 2009 (doi:10.1001/archneurol.2009.138).

CCR5 is involved in resolution of inflammation in proteoglycan-induced arthritis.

Abstract: Rheumatoid arthritis (RA) is a chronic, progressive autoimmune disease characterized by joint infiltration by several populations of leukocytes including T cells, B cells, macrophages and neutrophils (1). These infiltrating cells, in collaboration with resident cells, mediate cartilage destruction and bone erosion through a combination of cytokines, chemokines and matrix metalloproteases, (2)(3). In synovial fluid of RA patients, all four groups of chemokine families, CXC, CC, C and CX3C, and their receptors have been identified (3). The inhibition of infiltrating cells into the joint therefore represents an important step for therapeutic intervention. Chemokine (C-C motif) receptor 5 (CCR5), is a G-protein coupled chemokine receptor composed of seven transmembrane helices that is expressed by activated T cells, monocytes, dendritic cells, tissue macrophages, and neutrophils (4, 5). CCR5 is the natural receptor for the ligands CCL3 (MIP-1α), CCL4 (MIP-1β), and CCL5 (RANTES) all of which contribute to chemotactic activity in the synovial fluid of RA patients (6–8). The accumulation of CCR5+ T cells in the synovium of patients with RA suggests an important role in disease pathology (8). However, the chemotactic responses to RA synovial fluid were not dependent solely on a functional CCR5 receptor (9). The CCR5+ T cells express other chemokine receptors such as CCR1 which are also capable of responding to CCL3 and CCL5 (9). An allelic form of the CCR5 gene contains a 32-bp deletion (Δ32CCR5) which results in a nonfunctional CCR5 receptor. Several studies have addressed whether a loss of function mutation could have a protective effect against RA. Two of these studies demonstrated a statistical significant negative correlation between Δ32CCR5 and RA (10, 11) whereas three other studies were not significant (12–14). More recently, a meta-analysis of these 5 published studies demonstrated a significant negative association of Δ32CCR5 with RA (15) suggesting that - at least in the population of European ancestry - it may be protective. Treatment with a modified form of RANTES known as Met-RANTES, mildly inhibits arthritis in collagen-induced arthritis (CIA) and adjuvant induced arthritis (AIA) (15–17); however, these studies did not exclude the possibility that Met-RANTES interaction with CCR1 mediates inhibition. Use of a non-peptide antagonist of CCR5 in CIA revealed intact cellular immune responses but impaired T cell migration (16). Contrary to these findings, CIA in CCR5-deficient mice is similar to wild type mice (17). A novel role for CCR5 in the clearance of inflammation was recently elucidated. Early clues suggesting an anti-inflammatory role of CCR5 showed that the CCR5 antagonist Met-RANTES affected the uptake of apoptotic cells in a model of glomerulonephritis (18). Similarly, a deficiency in CCR5 or blocking CCR5 enhanced pathogenic inflammatory responses in hepatic liver disease, pancreatitis and glomerulonephritis (18–20). An important mechanistic explanation for these phenomena revealed that CCR5 may act as a novel decoy receptor on late apoptotic neutrophils and T cells. In this way, CCR5 can function to remove excess CCL3, CCL4, and CCL5 from tissue in the presence of pro-resolution lipid mediators (5). In this study we use an established model of RA, proteoglycan-induced arthritis (PGIA), to examine the function of CCR5 in disease. We found that CCR5 function is important in the clearance of CCL5 thereby promoting the resolution of inflammation.