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CXCR4
Kinds of CXCR4 Terms modified by CXCR4 Selected AbstractsA novel role of CXCR4 and SDF-1 during migration of cloacal muscle precursorsDEVELOPMENTAL DYNAMICS, Issue 6 2010Rizwan Rehimi Abstract The cloaca acts as a common chamber into which gastrointestinal and urogenital tracts converge in lower vertebrates. The distal end of the cloaca is guarded by a ring of cloacal muscles or sphincters, the equivalent of perineal muscles in mammals. It has recently been shown that the development of the cloacal musculature depends on hindlimb muscle formation. The signaling molecules responsible for the outward migration of hindlimb myogenic precursors are not known. Based on the expression studies for CXCR4 and SDF-1, we hypothesized a role of this signaling pair during cloacal muscle precursor migration. The aim of our study was to investigate the role of SDF-1/CXCR4 during cloacal muscle precursor migration in the chicken embryos. We show that SDF-1 is expressed in the cloacal region, and by experimentally manipulating the SDF-1/CXCR4 signaling, we can show that SDF-1 guides the migration of CXCR4-expressing cloacal muscle precursors. Developmental Dynamics 239:1622,1631, 2010. © 2010 Wiley-Liss, Inc. [source] A two-step model for Langerhans cell migration to skin-draining LNEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 11 2008Eduardo J. Villablanca Abstract Although the role of Langerhans cells (LC) in skin immune responses is still a matter of debate, it is known that LC require the chemokine receptor CCR7 for migrating to skin-draining LN. A report in the current issue of the European Journal of Immunology unfolds some of the intricacies of LC migration, showing that LC need CXCR4, but not CCR7, for their migration from the epidermis to the dermis. Thus, LC migration to skin-draining LN occurs in two distinct phases: a first step from the epidermis to the dermis regulated by CXCR4 and a second CCR7-dependent step from the dermis to LN. Here we discuss the potential implications of this new two-step LC migration paradigm. [source] Slamming the DOR on chemokine receptor signaling: Heterodimerization silences ligand-occupied CXCR4 and ,-opioid receptorsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 2 2008Dale Hereld Abstract Dimerization has emerged as a common mechanism for regulating the function of G protein-coupled receptors (GPCR). Among these are chemokine receptors, which detect various chemokines and regulate a range of physiological process, including immune cell trafficking, cancer cell migration, and neuronal patterning. Homo- and heterodimerization in response to chemokine binding has been shown to be required for the initiation or alteration of signaling by a number of chemokine receptors. In this issue of the European Journal of Immunology, a new study indicates that the formation of heterodimers of chemokine receptor CXCR4 and the ,-opioid receptor (DOR) prevents each of them from actively signaling, suggesting a novel mechanism for silencing GPCR function. See accompanying article: http://dx.doi.org/10.1002/eji200737630 [source] Up-regulation of leukocyte CXCR4 expression by sulfatide: An L-selectin-dependent pathway on CD4+ T cellsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 10 2007Pascal Duchesneau Abstract CXCR4 plays significant roles in immune and inflammatory responses and is important for selective recruitment of leukocytes. We previously showed that CXCR4 surface expression of human lymphocytes was affected by sulfatide, an in vivo ligand for L-selectin. Increased CXCR4 expression was shown to promote biologically relevant functions such as integrin-dependent adhesion and transmigration. Here, we show that sulfatide-induced CXCR4 up-regulation also occurs on other leukocyte subsets in humans and mice. B cells and CD4+CD25+ T cells had the highest CXCR4 up-regulation after sulfatide stimulation. Transfection of L-selectin was sufficient for K562 cells to acquire sulfatide-induced CXCR4 up-regulation, while analysis of L-selectin knockout mice revealed that this response was critically L-selectin dependent only for CD4+ T cells, suggesting an alternative pathway in CD8+ T cells and B cells. Sulfatide triggered several intracellular signaling events in CD4+ T cells, but only tyrosine kinase activation, including members of the Src family, were essential for L-selectin to CXCR4 signaling. CXCR4 up-regulation was rapid, enhanced CXCL12-induced signaling and increased chemotaxis toward CXCL12, and therefore has potentially important roles in vivo. Thus, the response to CXCL12 depends in part on tissue expression of sulfatide and, specifically in CD4+ T cells, also depends on the surface level of L-selectin. [source] Post-translational and cell type-specific regulation of CXCR4 expression by cytokinesEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 11 2003Hilke Brühl Abstract We have investigated the regulation and function of the chemokine receptor CXCR4 on neutrophils. CXCR4 is hardly detectable on neutrophils in the peripheral blood. However, overnight culture strongly up-regulates CXCR4 expression on the cell surface. The functional activity of CXCR4 on cultured neutrophils was confirmed by stromal cell-derived factor (SDF)-induced migration and up-regulation of the integrins CD11b and CD11c. CXCR4 surface expression on neutrophils but not on lymphocytes and monocytes is rapidly down-regulated after stimulation with TNF-, and IFN-,, resulting in significantly decreased SDF-induced functional responses of neutrophils. In contrast to surface expression, CXCR4 mRNA expression was several-fold increased in cytokine-stimulated neutrophils, suggesting a post-translational regulation. By confocal microscopy we demonstrate that CXCR4 is internalized after stimulation with TNF-, and IFN-,. The down-modulation of CXCR4 surface expression in response to TNF-, and IFN-, was fully reversible after cytokine removal. Further, CXCR4 down-modulation could be completely blocked by hypertonic sucrose and significantly reduced by chlorpromazine indicating the involvement of clathrin-coated pits. Internalization of CXCR4 by cytokines in a cell type-specific manner is a novel and functionally important mechanism of chemokine receptor regulation. [source] The SDF-1/CXCR4 pathway and the development of the cerebellar systemEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2005Tim O. Vilz Abstract Mice deficient for the chemokine receptor CXCR4 show premature translocation of granule cell neuroblasts from their germinal zone into the nascent cerebellum [Y.-R. Zuo et al. (1998)Nature, 393, 595,599]. Here, we used CXCR4-null mice to analyse the early development of cerebellar cortical inhibitory interneurons and pontine neurons which, in the adult, are synaptically integrated with granule cells. Cortical inhibitory interneuronal precursors normally invade the cerebellar anlage of CXCR4-deficient mice, but their dispersal is impeded by dislocated foci of proliferating granule cells, from which they are excluded. This is reminiscent of the strict exclusion of inhibitory interneuronal precursors from the superficial external granule cell layer. As inhibitory interneuronal precursors readily mingle with post-mitotic granule cells both in wild-type and CXCR4-null mice, these findings indicate that the developmentally regulated interactions between granule and inhibitory interneuronal precursors are independent of SDF-1/CXCR4 signalling. In contrast, the transit of pontine neurons from the rhombic lip through the anterior extramural stream to the basilar pons is disrupted in CXCR4-deficient animals. Migrating pontine neurons express CXCR4, and in CXCR4-null animals these cells are found displaced deep into the brainstem. Consequently, nascent pontine nuclei in CXCR4-deficient animals are hypoplastic. Moreover, they fail to express plexin D1, suggesting that SDF-1/CXCR4 signalling may also impinge on axon guidance critical to the orderly formation of granule cell mossy fibre afferents. [source] Cloning and characterization of SDF-1,, a novel SDF-1 chemokine transcript with developmentally regulated expression in the nervous systemEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2000Marc Gleichmann Abstract The cytokines SDF-1, and -1, are two alternatively spliced variants of the CXC (,) chemokines that are highly conserved among species. SDF-1, was shown to function as a B-cell maturation factor, a ligand for the CXCR4 (LESTR/fusin) chemokine receptor, thereby inhibiting replication of T cell-tropic HIV-1 strains and inducing cell death in human neuronal cell lines. In this report the cloning of the rat SDF-1, cDNA and a new SDF-1 isoform, SDF-1,, are presented. Using Northern blot analysis, the expression pattern of both isoforms was studied in different tissues and it is shown that during postnatal development of the central and peripheral nervous system SDF-1,- and SDF-1,-mRNA expression is inversely regulated. Whilst SDF-1,-mRNA is the predominant isoform in embryonic and early postnatal nerve tissue, SDF-1,-mRNA is expressed at higher levels in adulthood. After peripheral nerve lesion a transient increase in SDF-1,-mRNA expression is observed. As revealed by in situ hybridization, neurons and Schwann cells are the main cellular sources of both SDF-1, and SDF-1, mRNAs in the nervous system. Computer-assisted analysis revealed that both transcripts encode secreted peptides with putative proteolytic cleavage sites which might generate novel neuropeptides. [source] Structure,function relationship of novel X4 HIV-1 entry inhibitors , L- and D-arginine peptide-aminoglycoside conjugatesFEBS JOURNAL, Issue 24 2007Ravi Hegde We present the design, synthesis, anti-HIV-1 and mode of action of neomycin and neamine conjugated at specific sites to arginine 6- and 9-mers d - and l -arginine peptides (APACs). The d -APACs inhibit the infectivity of X4 HIV-1 strains by one or two orders of magnitude more potently than their respective l -APACs. d -arginine conjugates exhibit significantly higher affinity towards CXC chemokine receptor type 4 (CXCR4) than their l -arginine analogs, as determined by their inhibition of monoclonal anti-CXCR4 mAb 12G5 binding to cells and of stromal cell-derived factor 1, (SDF-1,)/CXCL12 induced cell migration. These results indicate that APACs inhibit X4 HIV-1 cell entry by interacting with CXCR4 residues common to glycoprotein 120 and monoclonal anti-CXCR4 mAb 12G5 binding. d -APACs readily concentrate in the nucleus, whereas the l -APACs do not. 9-mer- d -arginine analogues are more efficient inhibitors than the 6-mer- d -arginine conjugates and the neomycin- d -polymers are better inhibitors than their respective neamine conjugates. This and further structure,function studies of APACs may provide new target(s) and lead compound(s) of more potent HIV-1 cell entry inhibitors. [source] Isolated human astrocytes are not susceptible to infection by M- and T-tropic HIV-1 strains despite functional expression of the chemokine receptors CCR5 and CXCR4 ,GLIA, Issue 3 2001Agnès Boutet Abstract Within the brain, HIV-1 targets the microglia and astrocytes. Previous studies have reported that viral entry into astrocytes is independent of CD4, in contrast to microglia. We aimed to determine whether chemokine receptors play a role in mediating CD4-independent HIV-1 entry into astrocytes. We found that embryonic astrocytes and microglial cells express CCR5, CCR3, and CXCR4 transcripts. Intracellular calcium levels in astrocytes were found to increase following application of RANTES, MIP-1, (CCR5-agonist), SDF-1, (CXCR4-agonist), but not eotaxin (CCR3-agonist). In microglial cells, eotaxin was also able to modulate internal calcium homeostasis. CD4 was not present at the cell surface of purified astrocytes but CD4 mRNA could be detected by RT-PCR. Neither HIV-19533 (R5 isolate) nor HIV-1LAI (X4 isolate) penetrated into purified astrocytes. In contrast, mixed CNS cell cultures were infected by HIV-19533 and this was inhibited by anti-CD4 mAb in 4/4 tested cultures and by anti-CCR5 mAb in 2/4. Thus, the HIV-1 R5 strain requires CD4 to penetrate into brain cells, suggesting that CCR5 cannot be used as the primary receptor for M-tropic HIV-1 strains in astrocytes. Moreover, inconstant inhibition of HIV-1 entry by anti-CCR5 mAb supports the existence of alternative coreceptors for penetration of M-tropic isolates into brain cells. GLIA 34:165,177, 2001. © 2001 Wiley-Liss, Inc. [source] Increased expression of SDF-1/CXCR4 is associated with lymph node metastasis of invasive micropapillary carcinoma of the breastHISTOPATHOLOGY, Issue 6 2009Fangfang Liu Aims:, Stromal cell-derived factor-1 (SDF-1) and its receptor CXCR4 are implicated in tumour chemotaxis and metastasis. The aim was to examine their roles in the metastasis of invasive micropapillary carcinoma (IMPC) of the breast, a tumour with a high propensity for nodal spread. Methods and results:, We compared the expression of SDF-1 and CXCR4 in 103 cases of breast cancer containing IMPC components with a control group of 96 cases of invasive ductal carcinoma (IDC), not otherwise specified type by immunohistochemistry and chemical in situ hybridization (CISH). The results showed that the predominant cytoplasmic expression of both SDF-1 and CXCR4 was greater in tumour cells of the IMPC components than in those of the non-IMPC components and the control IDC cases, and was correlated significantly with the number of positive lymph nodes (P < 0.05). SDF-1 expression on cell membranes was less frequently identified in IMPC than IDC (P = 0.021). Immunohistochemical detection of SDF-1 in endothelial cells of lymphatic vessels was more common in IMPC (P = 0.007) and correlated significantly with lymph node status (P = 0.002), although SDF-1 mRNA was rarely detected by CISH. Conclusions:, This study suggests that up-regulation of cytoplasmic expression of SDF-1/CXCR4 might be one of the molecular mechanisms facilitating lymph node metastasis of IMPC. [source] Comparison of two genotypic algorithms to determine HIV-1 tropism,HIV MEDICINE, Issue 1 2008C Soulié Objectives One or both of two co-receptors, CCR5 (R5) and CXCR4 (X4), are used by HIV-1 to enter into host cells. The glycoprotein 120 (gp120) V3 sequence is correlated with the R5 and X4 phenotype. CCR5 inhibitors are specifically active against R5 viruses, suggesting the need to determine tropism before the use of these antagonists. A comparison of the position-specific scoring matrices (PSSM) and Geno2pheno algorithms based on the V3 loop gp120 sequences and previously described to be correlated to the R5 or X4 phenotype was carried out. Methods V3 envelope (env) genes from 83 plasma samples were amplified and sequenced, and 69 sequences were analysed with the PSSM and Geno2pheno algorithms. Results These two algorithms were concordant in 86.5% of cases. The Geno2pheno algorithm gave a tropism result more frequently than the PSSM algorithm, but R5X4 or X4 viruses were less frequently detected by the Geno2pheno algorithm. R5X4 or X4 tropism was predicted in 29.9% of samples. There was more R5X4 co-receptor use in the antiretroviral-treated group than in the antiretroviral-naïve group. Conclusions It is advisable to run a validated co-receptor use prediction tool before using co-receptor antagonists. If genotyping methods are considered, the PSSM and Geno2pheno algorithms are complementary and both are necessary. The association between predicted co-receptor use and virological response to co-receptor antagonists needs to be thoroughly evaluated. [source] CXCR4: chemokine receptor extraordinaireIMMUNOLOGICAL REVIEWS, Issue 1 2000Craig Murdoch First page of article [source] Neutrophil mobilization and clearance in the bone marrowIMMUNOLOGY, Issue 3 2008Rebecca C. Furze Summary The bone marrow is the site of neutrophil production, a process that is regulated by the cytokine granulocyte colony-stimulating factor (G-CSF). Mature neutrophils are continually released into the circulation, with an estimated 1011 neutrophils exiting the bone marrow daily under basal conditions. These leucocytes have a short half-life in the blood of ,6·5 hr, and are subsequently destroyed in the spleen, liver and indeed the bone marrow itself. Additionally, mature neutrophils are retained in the bone marrow by the stromal cell-derived factor (SDF-1,)/chemokine (C-X-C motif) receptor 4 (CXCR4) chemokine axis and form the bone marrow reserve. Following infection or inflammatory insult, neutrophil release from the bone marrow reserve is substantially elevated and this process is mediated by the co-ordinated actions of cytokines and chemokines. In this review we discuss the factors and molecular mechanisms regulating the neutrophil mobilization and consider the mechanisms and functional significance of neutrophil clearance via the bone marrow. [source] The modulatory effects of lipopolysaccharide-stimulated B cells on differential T-cell polarizationIMMUNOLOGY, Issue 2 2008Hui Xu Summary Lipopolysaccharide (LPS) is a major component of environmental microbial products. Studies have defined the LPS dose as a critical determining factor in driving differential T-cell polarization but the direct effects of LPS on individual antigen-presenting cells is unknown. Here, we investigated the effects of LPS doses on naive B cells and the subsequent modulatory effects of these LPS-activated B cells on T-cell polarization. The LPS was able to induce a proliferative response starting at a dose of 100 ng/ml and was capable of enhancing antigen internalization at a dose of 1 ,g/ml in naive B cells. Following LPS stimulation, up-regulation of the surface markers CD40, CD86, I-Ad, immunoglobulin M, CD54 and interleukin-10 production, accompanied by down-regulation of CD5 and CD184 (CXCR4) were observed in a LPS dose-dependent manner. Low doses (< 10 ng/ml) of LPS-activated B cells drove T helper type 2 polarization whereas high doses (> 0·1 ,g/ml) of LPS-activated B cells resulted in T regulatory type 1 cell polarization. In conclusion, LPS-activated B cells acquire differential modulatory effects on T-cell polarization. Such modulatory effects of B cells are dependent on the stimulation with LPS in a dose-dependent manner. These observations may provide one of the mechanistic explanations for the influence of environmental microbes on the development of allergic diseases. [source] CD1d-restricted natural killer T cells are potent targets for human immunodeficiency virus infectionIMMUNOLOGY, Issue 1 2003Richardson Fleuridor Summary Invariant human natural killer T cells (NKT) express a restricted T-cell receptor (TCR) V,24V,11 repertoire. These cells share both phenotypic and functional similarities between NK and T cells. Given the emerging role of NKT cells as critical cells in bridging the gap between innate and adaptive immunity, we examined their susceptibility to productive human immunodeficiency virus (HIV) infection by T-tropic, M-tropic, and primary isolates of HIV. We generated three human NKT cell clones (CA5, CA29, and CA31). Phenotypic characterization of these V,24+ V,11+ clones indicated that they were predominately positive for CD4, CD161, HLA-DR, CD38, CD45RO, and CD95 expression. The NKT cell clones expressed significantly more surface CCR5 molecules/cell and lower CXCR4 molecules/cell than phytohaemagglutinin-stimulated peripheral blood mononuclear cells (PBMC). Consistent with the surface expression of CCR5 and CXCR4, the NKT clones were also selectively susceptible to HIV M-tropic, T-tropic, and primary isolate infection, as evaluated by both HIV p24 enzyme-linked immunosorbent assay and intracellular staining of HIV proteins. The amount of p24 production was dependent on the NKT clone studied and the HIV strain used. Clones CA29 and CA31 were also susceptible to HIV IIIB infection. The virions produced by these clones were able to productively infect PHA-stimulated PBMCs with the same kinetics as for primary infection of CD4+ blast. Collectively, this data demonstrates that NKT cells can be a target for productive HIV infection but with a lag in the time to peak p24 production. [source] CXCL12 Is a constitutive and inflammatory chemokine in the intestinal immune systemINFLAMMATORY BOWEL DISEASES, Issue 4 2010Iris Dotan MD Abstract Background: Inflammatory bowel disease (IBD) is characterized by increased lymphocytic infiltrate to the lamina propria (LP) and upregulation of inflammatory chemokines and receptors. CXCL12 is a constitutive chemokine involved in lung, brain, and joint inflammation. We hypothesized that CXCL12 and its receptor, CXCR4, would have a constitutive and inflammatory role in the gut. Methods: Intestinal epithelial cells (IECs) and T lymphocytes were isolated from intestinal mucosa of IBD and control patients undergoing bowel resection. Autologous T cells were isolated from peripheral blood (PB). CXCL12 and CXCR4 expression by IECs was assessed by polymerase chain reaction and immunohistochemistry, lymphocyte phenotype by flow cytometry, and migration by Transwells. Results: IECs expressed CXCL12 and expression was increased and more diffuse in IBD compared to normal crypts (ulcerative colitis [UC] > Crohn's disease [CD], inflamed > noninflamed). CXCR4 was expressed by IECs, LP T cells (LPTs), and PB T cells (PBTs), and CXCR4+ cells were increased in IBD LP in situ. PBTs and LPTs from all patients had a high and comparable migration toward CXCL12 (P < 0.0001 and P < 0.05 vs. medium, respectively). Migration toward IBD-IEC-derived supernatant was significantly higher compared to normal. Antibodies against CXCR4 and CXCL12 blocked migration. Conclusions: CXCL12 is expressed by normal IECs and upregulated and differentially distributed in IBD IECs. CXCR4 is expressed by IECs and LPTs, and CXCR4+ cells are significantly increased in IBD LP. CXCL12 is chemotactic for both PBTs and LPTs. Thus, CXCL12 and CXCR4 have a constitutive and inflammatory role in the intestinal mucosa and their selective therapeutic manipulation may be considered in IBD management. (Inflamm Bowel Dis 2009;) [source] Phosphoglycerate kinase 1 a promoting enzyme for peritoneal dissemination in gastric cancer,INTERNATIONAL JOURNAL OF CANCER, Issue 6 2010Derek Zieker Abstract Peritoneal carcinomatosis is a frequent finding in gastric cancer associated with a poor prognosis. The features that enable gastric tumors to disseminate are poorly understood until now. Previously, we showed elevated mRNA levels of phosphoglycerate kinase 1 (PGK1), an adenosine triphosphate-generating enzyme in the glycolytic pathway, the chemokine receptor 4 (CXCR4), the corresponding chemokine ligand 12 (CXCL12) and ,-catenin in specimens from gastric cancer patients with peritoneal carcinomatosis. In this study, the influence of PGK1 on CXCR4 and ,-catenin was assessed as well as the invasiveness of PGK1 overexpressing cancer cells. In this current study, we found that PGK1 regulates the expression of CXCR4 and ,-catenin at the mRNA and protein levels. On the other hand, CXCR4 regulates the expression of PGK1. Plasmid-mediated overexpression of PGK1 dramatically increased the invasiveness of gastric cancer cells. Interestingly, inhibition of CXCR4 in cells overexpressing PGK1 produced only a moderate reduction of invasiveness suggesting that, PGK1 itself has a critical role in tumor invasiveness. Immunohistochemistry in specimens from diffuse gastric cancer patients also revealed an overexpression of PGK1 in patients with development of peritoneal carcinomatosis. Therefore, PGK1 may be a crucial enzyme in peritoneal dissemination. Together these findings suggest that the enhanced expression of PGK1 and its signaling targets CXCR4 and ,-catenin in gastric cancer cells promote peritoneal carcinomatosis. Thus, PGK1 may serve as prognostic marker and/or be a potential therapeutic target to prevent dissemination of gastric carcinoma cells into the peritoneum. [source] Inhibition of accelerated tumor growth by blocking the recruitment of mobilized endothelial progenitor cells after chemotherapyINTERNATIONAL JOURNAL OF CANCER, Issue 7 2009Junichi Murakami Abstract It has been suggested that immature progenitor cells mobilize from bone marrow into the peripheral blood in response to the chemotherapy-induced myelosuppression. We investigated how the mobilization of immature progenitor cells affects tumor growth after chemotherapy. We found significantly increased numbers of CD34+/Flk-1+ endothelial progenitor cells in the peripheral blood of mice 1 week after the administration of 100 mg/kg cyclophosphamide vs. a saline injection (0.39 ± 0.09% vs. 0.20 ± 0.10%, respectively; p < 0.05). Tumor growth in the mice given chemotherapy was almost 1.3-fold faster than that in the mice given saline (268 ± 66 mg vs. 210 ± 3 5 mg, respectively; p < 0.05). Histological examination of tumor tissue revealed significantly higher microvessel density and more Ki67-positive cells, but significantly fewer apoptotic cells, in the mice given chemotherapy than in those given saline (p < 0.05). Furthermore, we detected significantly more bone marrow-derived cells, some of which stained positively for CD34 and were localized in the vessels, in tumor tissue from the mice given chemotherapy than in that from the mice given saline. However, the transient disruption of the SDF-1/CXCR4 axis by the antibody neutralization of CXCR4, which occurred over 1 week, blocked the recruitment of bone marrow-derived cells into the tumor tissue, and resulted in complete inhibition of accelerated tumor growth after chemotherapy. Our results show that chemotherapy induced the mobilization of endothelial progenitor cells and accelerated tumor growth, but that transient disruption of the SDF-1/CXCR4 axis could prevent accelerated tumor growth by blocking the recruitment of mobilized endothelial progenitor cells after chemotherapy. © 2008 Wiley-Liss, Inc. [source] Defining a role for Sonic hedgehog pathway activation in desmoplastic medulloblastoma by identifying GLI1 target genesINTERNATIONAL JOURNAL OF CANCER, Issue 1 2009Joon Won Yoon Abstract A subgroup of medulloblastomas shows constitutive activation of the Sonic hedgehog pathway with expression of GLI1. We identified the subset of GLI1 transforming target genes specifically expressed in medulloblastomas by comparing GLI1 targets in RK3E cells transformed by GLI1 with the gene expression profile of Sonic hedgehog signature medulloblastomas. We identified 1,823 genes whose expression was altered more than 2-fold in 2 independent RK3E + GLI1 cell lines. We identified 25 whose expression was altered similarly in medulloblastomas expressing GLI1. We identified potential GLI binding elements in the regulatory regions of 10 of these genes, confirmed that GLI1 binds the regulatory regions and activates transcription of select genes, and showed that GLI1 directly represses transcription of Krox-20. We identified upregulation of CXCR4, a chemokine receptor that plays roles in the proliferation and migration of granule cell neuron precursors during development, supporting the concept that reinitiation of developmental programs may contribute to medulloblastoma tumorigenesis. In addition, the targets suggest a pathway through which GLI1 may ultimately affect medulloblastoma cell proliferation, survival and genomic stability by converging on p53, SGK1, MGMT and NTRK2. We identify a p53 mutation in RK3E + GLI1 cells, suggesting that p53 mutations may sometimes shift the balance toward dysregulated tumor cell survival. © 2008 Wiley-Liss, Inc. [source] Gene and protein expressions in human cord blood cells after exposure to acrylonitrileJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 4 2005Cristina Diodovich Abstract Acrylonitrile is a very high volume industrial chemical used primarily in the manufacture of plastics and rubber, which displays a pronounced acute toxicity and may be carcinogenic. The damage to the hematopoietic function by acrylonitrile may result from interference with cytokine production and cytokine receptor binding. Our present data show that acrylonitrile modulates the expression of some genes implicated in cell differentiation, cell-cycle progression, and clonogenic potential of human cord blood cells. A macroarray hybridization analysis showed that expression of the CXCR4, MCP-1, and MRP8 genes was modified by acrylonitrile exposure. Moreover, the acrylonitrile cell target seems to be the myeloid compartment, as assessed by a CFU-GM assay. In particular, the downregulation of CXCR4, MCP1, and MRP8 can be responsible for the observed reduction of cell proliferation and clonogenic capability of CFU-GM precursors. A Western blot assay showed an acrylonitrile-dependent induction of Bax, while Bcl-2 expression changed only after 48 h of chemical exposure. Bax was overexpressed in respect to Bcl-2, and this fact can be responsible for the induction in cell death after 24 h of treatment. C-fos and c-jun were also downregulated after 24 h and 6 h of treatment, respectively. © 2005 Wiley Periodicals, Inc. J Biochem Mol Toxicol 19:204,212, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20090 [source] Restoration of Bone Mass and Strength in Glucocorticoid-Treated Mice by Systemic Transplantation of CXCR4 and Cbfa-1 Co-Expressing Mesenchymal Stem Cells,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 5 2009Chun-Yang Lien Abstract Transplantation of gene-modified mesenchymal stem cells (MSCs) in animals for bone regeneration therapy has been evaluated extensively in recent years. However, increased endosteal bone formation by intravenous injection of MSCs ectopically expressing a foreign gene has not yet been shown. Aside from the clearance by lung and other tissues, the surface compositions of MSCs may not favor their bone marrow (BM) migration and engraftment. To overcome these hurdles, a gene encoding the chemokine receptor largely responsible for stromal-derived factor-1 (SDF-1)-mediated BM homing and engraftment of hematopoietic stem cells (HSCs), CXCR4, was transduced into mouse C3H10T1/2 cells by adenovirus infection. A dose-dependent increase of CXCR4 surface expression with a parallel enhanced chemotaxis toward SDF-1 in these cells after virus infection was clearly observed. Higher BM retention and homing of CXCR4-expressing MSCs were also found after they were transplanted by intramedullary and tail vein injections, respectively, into immunocompetent C3H/HeN mice. Interestingly, a full recovery of bone mass and a partial restoration of bone formation in glucocorticoid-induced osteoporotic mice were observed 4 wk after a single intravenous infusion of one million CXCR4-expressing C3H10T1/2 cells. In the meantime, complete recovery of bone stiffness and strength in these animals was consistently detected only after a systemic transplantation of CXCR4 and Cbfa-1 co-transduced MSCs. To our knowledge, this is the first report to show unequivocally the feasibility of ameliorating glucocorticoid-induced osteoporosis by systemic transplantation of genetically manipulated MSCs. [source] Constitutive association of cell surface CCR5 and CXCR4 in the presence of CD4,JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 4 2004Dr. Jinhai Wang Abstract Chemokine receptors CCR5 and CXCR4 are the major coreceptors of HIV-1 infection and also play fundamental roles in leukocyte trafficking, metastasis, angiogenesis, and embyogenesis. Here, we show that transfection of CCR5 into CXCR4 and CD4 expressing 3T3 cells enhances the cell surface level of CXCR4. In CCR5 high expressing cells, cell surface level of CXCR4 was incompletely modulated in the presence of the CXCR4 ligand CXCL12/SDF-1,. CCR5 was resistant to ligand-dependent modulation with the CCR5 ligand CCL5/RANTES. Confocal laser microscopy revealed that CCR5 was colocalized with CXCR4 on the cell surface. In CD4 expressing CCR5 and CXCR4 double positive NIH 3T3 cells, immunoprecipitation followed by Western blot analysis revealed that CCR5 was associated with CXCR4 and CD4. CXCR4 and CCR5 were not co-immunoprecipitated in cells expressing CCR5 and CXCR4 but without CD4 expression. Compared to NIH 3T3CD4 cells expressing CXCR4, the entry of an HIV-1 X4 isolate (HCF) into NIH 3T3CD4 expressing both CXCR4 and CCR5 was reduced. Our data indicate that chemokine receptors interact with each other, which may modulate chemokine,chemokine receptor interactions and HIV-1 coreceptor functions. Published 2004 Wiley-Liss, Inc. [source] Chemokine receptor expression in non-melanoma skin cancerJOURNAL OF CUTANEOUS PATHOLOGY, Issue 7 2008Jeff Basile Background:, Previous studies suggest that chemokines and chemokine receptors have a role in the metastatic process. A correlation exists between the specific expression of these chemoattractive, pro-inflammatory cytokines and the ability of cancer to disseminate. Prior studies have shown that in metastatic melanoma and squamous cell carcinoma of the head and neck upregulation of CXC (,) chemokine receptor (CXCR)4 and CC (,) chemokine receptor (CCR)7 expression is accompanied by downregulation of the chemokine receptor CCR6. However, the expression patterns of CCR6, CCR7 and CXCR4 in non-melanoma skin cancer have yet to be elucidated. Methods:, The expression patterns of CCR6, CCR7 and CXCR4 were determined using an immunohistochemical approach on formalin-fixed, paraffin-embedded normal, pre-cancerous actinic (solar) keratosis, squamous cell carcinoma and basal cell carcinoma tissues. Results:, Analysis of chemokine receptor expression showed downregulation of CCR6 and upregulation of CCR7 and CXCR4 in potentially metastatic non-melanoma skin cancer, invasive squamous cell carcinoma, but this pattern did not exist in non-melanoma skin cancer with no metastatic potential, basal cell carcinoma; or actinic keratosis, when compared with normal skin. Conclusions:, Chemokine receptor expression may influence the biological behavior of non-melanoma skin cancer. The exact mechanism by which this occurs requires further study. [source] Do human polyoma viruses and human immunodeficiency virus share common co-receptors?JOURNAL OF MEDICAL VIROLOGY, Issue 1 2010Kalin Borissov Abstract Host and/or viral factors involved in human polyomavirus (HPoV) infection in persons living with HIV remain unknown. A hypothesis is outlined suggesting the importance of the co-receptors CCR5, CCR2, and CXCR4 not only for HIV, but also for HPoV. Functionally capable receptors coded by wild-type (wt) genotypes could facilitate internalization of HPoV in the cell resulting in brain and/or kidney infection/s in HIV infected individuals. Forty-nine Bulgarians with HIV, all treated by HAART, without neurological and/or kidney disorders, were tested for JCV and BKV and genotyped for CCR5 (CCR5del32), CCR2 (CCR2-64I), and CXCR4 (SDF1-3,A). In 27/49 (55.1%) individuals a co-infection with HPoV was identified,BKV in 12/49 (24.5%), JCV,in another 12/49 (24.5%), and both viruses,in 3/49 (6.1%). A high frequency of wt CCR5 was found in patients with HPoV (91.7% for BKV and JCV and in 100% with both viruses). V/V of CCR2 was presented in 75% for BKV and JCV and in 66.7% for BKV plus JCV. SDF1-3,G/G predominated in JCV infected patients (75%), while G/A and A/A genotypes were more frequent in patients with BKV (41.7%). Also, 21/22 (95.4%) persons without HPoV infection were heterozygous for SDF1 and CCR2. The number of individuals bearing wt of all co-receptors in the group of persons not infected with HPoV was lower (P,=,0.03) than that with polymorphism/s in one or two genes (SDF1 and CCR2) in the same group. The results suggest a probable role of co-receptors used by HIV to facilitate infection with HPoV. J. Med. Virol. 82:8,13, 2010. © 2009 Wiley-Liss, Inc. [source] Molecular characterization of the env gene of two CCR5/CXCR4-independent human immunodeficiency 2 primary isolates,JOURNAL OF MEDICAL VIROLOGY, Issue 11 2009Quirina Santos-Costa Abstract Human immunodeficiency virus 2 (HIV-2) infection is characterized by a slower disease progression and lower transmission rates. The molecular features that could be assigned as directly involved in this in vivo phenotype remain essentially unknown, and the importance of HIV-2 as a model to understand pathogenicity of HIV infection has been frequently underestimated. The early events of the HIV replication cycle involve the interaction between viral envelope glycoproteins and cellular receptors: the CD4 molecule and a chemokine receptor, usually CCR5 or CXCR4. Despite the importance of these two chemokine receptors in human immunodeficiency virus 1 (HIV-1) entry into cells, we have previously shown that in some HIV-2 asymptomatic individuals, a viral population exists that is unable to use both CCR5 and CXCR4. The goal of the present study was to investigate whether possible regions in the env gene of these viruses might account for this phenotype. From the molecular characterization of these env genes we could not detect any correlation between V3 loop sequence and viral phenotype. In contrast, it reveals the existence of remarkable differences in the V1/V2 and C5 regions of the surface glycoprotein, including the loss of a putative glycosilation site. Moreover, in the transmembrane glycoprotein some unique sequence signatures could be detected in the central ectodomain and second heptad repeat (HR2). Some of the mutations affect well-conserved residues, and may affect the conformation and/or the dynamics of envelope glycoproteins complex, including the SU,TM association and the modulation of viral entry function. J. Med. Virol. 81:1869,1881, 2009. © 2009 Wiley-Liss, Inc. [source] Association of IL-4 589 C/T promoter and IL-4R,I50V receptor polymorphism with susceptibility to HIV-1 infection in North IndiansJOURNAL OF MEDICAL VIROLOGY, Issue 6 2009Animesh Chatterjee Abstract The clinical course and outcome of HIV-1 infection are highly variable among individuals. Interleukin 4 (IL-4) is a key T helper 2 cytokine with various immune-modulating functions including induction of immunoglobulin E (IgE) production in B cells, downregulation of CCR5 and upregulation of CXCR4, the main co-receptors for HIV. Our objective is to investigate whether single-nucleotide polymorphisms (SNPs) in the IL-4 promoter 589 C/T and IL-4 R, I50V affect the susceptibility to HIV infection and its progression to AIDS in North Indian individuals. The study population consisted of 180 HIV-1 seropositive (HSP) stratified on the basis of disease severity (stage I, II, III), 50 HIV-1 exposed seronegative (HES), and 305 HIV-1 seronegative (HSN) individuals. The subjects were genotyped for IL-4 589 C/T promoter polymorphism and IL-4 R, I50V by polymerase chain reaction restriction fragment length polymorphism. The results showed that IL-4 589 C/T was not associated with the risk of HIV infection and disease progression. However, the IL-4R, I50 allele and genotype was significantly increased in HSP compared to HSN and HSP and was associated with risk of HIV infection. The frequency of IL-4R, I50 allele in the HSP group was higher than in HSN (76.11 vs. 64.75%; P,=,0.000; OR,=,1.734) and HES (76.11% vs. 62.00%; P,=,0.007; OR,=,1.953). Homozygous IL-4R, I50I genotype was significantly increased in HSP group compared with HSN (58.88% vs. 44.26%; P,=,0.002; OR,=,1.804) and HES (58.88% vs. 42.00%; P,=,0.038; OR,=,1.978). The present study for the first time suggests an association of IL-4R, I50 allele with increased likelihood of HIV-1 infection in North Indian population. Further studies are required to confirm these findings and understand the effect of IL-4R, polymorphism on the outcome of HIV-1 infection. J. Med. Virol. 81:959,965, 2009. © 2009 Wiley-Liss, Inc. [source] Characterization of a chemokine receptor CCR5-negative T cell line and its use in determining human immunodeficiency virus type 1 phenotypeJOURNAL OF MEDICAL VIROLOGY, Issue 2 2008Dorothea Binninger-Schinzel Abstract A human CD4-positive T cell line from a donor homozygous negative for the chemokine receptor CCR5 was established, characterized, and used for determining the coreceptor usage of human immunodeficiency virus type 1 (HIV-1) isolates. Clones of this IL-2 dependent human T-cell lymphotropic virus type 1 (HTLV-I) immortalized cell line, named IsnoR5 clones 1 and 2, are susceptible to infection by HIV-1 isolates that use CXCR4 as a coreceptor but resistant to infection by CCR5 tropic HIV-1 viruses. HIV-1 isolates whose replication is inhibited in IsnoR5 cells in the presence of the bicyclam AMD 3100, a CXCR4 specific inhibitor, utilize a coreceptor distinct from CCR5 and CXCR4. Using a panel of primary HIV-1 isolates we have shown that a single T cell line is sufficient to discriminate between use of CCR5, CXCR4 or an alternative coreceptor. As IsnoR5 clone 1 cells revealed the existence of even minor populations of CXCR4-using virus variants, they could be useful for the early identification of changes in coreceptor usage in HIV infected individuals facilitating the timely introduction of appropriate clinical treatments. J. Med. Virol. 80:192,200, 2008. © 2007 Wiley-Liss, Inc. [source] Chemokine receptors and neurotrophic factors: Potential therapy against aids dementia?JOURNAL OF NEUROSCIENCE RESEARCH, Issue 2 2008Italo Mocchetti Abstract Chemokine receptors, in particular, CXCR4 and CCR5, mediate human immunodeficiency virus type 1 (HIV-1) infection of immunocompetent cells and the apoptosis of these cells. However, the virus does not infect neurons. Yet through a variety of mechanisms, HIV promotes glial cell activation, synaptodendritic alterations, and neuronal loss that ultimately lead to motor and cognitive impairment. Chemokines and chemokine receptors are abundant in the adult central nervous system and play a role in neuronal apoptosis evoked by HIV proteins. Thus, reducing the availability of chemokine receptors may prevent the neuronal degeneration seen in HIV-positive patients. In this article, we present and discuss a recent experimental approach aimed at testing effective neuroprotective therapies against HIV-mediated neuronal degeneration. © 2007 Wiley-Liss, Inc. [source] Impaired SDF1/CXCR4 signaling in glial progenitors derived from SOD1G93A miceJOURNAL OF NEUROSCIENCE RESEARCH, Issue 11 2007Yongquan Luo Abstract Mutations in the superoxide dismutase 1 (SOD1) gene are associated with familial amyotrophic lateral sclerosis (ALS), and the SOD1G93A transgenic mouse has been widely used as one animal model for studies of this neurodegenerative disorder. Recently, several reports have shown that abnormalities in neuronal development in other models of neurodegeneration occur much earlier than previously thought. To study the role of mutant SOD1 in glial progenitor biology, we immortalized glial restricted precursors (GRIPs) derived from mouse E11.5 neural tubes of wild-type and SOD1G93A mutant mice. Immunocytochemistry using cell lineage markers shows that these cell lines can be maintained as glial progenitors, because they continue to express A2B5, with very low levels of glial fibrillary acidic protein (astrocyte), ,III-tubulin (neuron), and undetected GalC (oligodendrocyte) markers. RT-PCR and immunoblot analyses indicate that the chemokine receptor CXCR4 is reduced in SOD1G93A GRIPs. Subsequently, SOD1G93A GRIPs are unable to respond to SDF1, to activate ERK1/2 enzymes and the transcription factor CREB. This may be one pathway leading to a reduction in SOD1G93A cell migration. These data indicate that the abnormalities in SOD1G93A glial progenitor expression of CXCR4 and its mediated signaling and function occur during spinal cord development and highlight nonneuronal (glial) abnormalities in this ALS model. © 2007 Wiley-Liss, Inc. [source] Human immunodeficiency virus type 1 gp120 inhibits long-term potentiation via chemokine receptor CXCR4 in rat hippocampal slicesJOURNAL OF NEUROSCIENCE RESEARCH, Issue 3 2006Jun Dong Abstract Human immunodeficiency virus type 1 (HIV-1) infection in its human host often results in progressive dementia and encephalopathy in adults and children, respectively. The mechanisms underlying virus-induced neurocognitive dysfunction are not fully understood. However, several studies strongly suggest that secretory viral and immune products from infected brain macrophages and microglia affect the onset and tempo of disease. One critical neurotoxin among these secretory products is the HIV-1 envelope glycoprotein gp120. To better understand how HIV-1 gp120 may affect cognitive function, we studied its effects on long-term potentiation (LTP) in the CA1 region of rat hippocampus, the brain region best linked to learning and memory. Although no effects were observed on basal synaptic transmission, HIV-1 gp120 inhibited LTP in a concentration-dependent manner in the presence of ,-aminobutyric acid type A (GABAA) receptor antagonist. Heat-inactivated gp120 failed to block LTP. The HIV-1 gp120-mediated LTP inhibition was blocked by T140, a chemokine receptor CXCR4 antagonist, demonstrating gp120 inhibition of LTP via CXCR4. HIV-1 gp120 V3 loop peptides mimicked the inhibitory effects of HIV-1 gp120 protein on LTP. Monoclonal antibodies against the V3 loop epitope KRIHI eliminated the HIV-1 gp120 effects on LTP. These results further underscore the importance of HIV-1 gp120 in the pathogenesis of HIV-1-associated cognitive impairments seen during progressive viral infection. © 2006 Wiley-Liss, Inc. [source] | |||||||||||||||||||||||||||||||||||||