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1: Neuroimmunomodulation, 2010 Aug 19, 18(1)
CCL5, CXCL10 and CXCL11 Chemokines in Patients with Active and Stable Relapsing-Remitting Multiple Sclerosis.

[Abstract]Objective: Chemokines are involved in the migration of inflammatory cells to the central nervous system in multiple sclerosis (MS). The aim of our study was to estimate the concentrations of CCL5, CXCL10 and CXCL11 in serum and cerebrospinal fluid (CSF) samples of relapsing-remitting MS (RRMS) patients during both relapse and stable disease, and to compare the results with those of controls. We also decided to evaluate the effect of methylprednisolone (MP) therapy on CCL5, CXCL10 and CXCL11 serum concentrations in MS patients with relapse. Methods: The study groups consisted of 17 RRMS patients during relapse, 30 RRMS patients in remission and 25 patients with tension headache with no symptoms of inflammatory disease as controls. In the group of relapsing MS patients, blood samples were obtained before steroid therapy and after a 5-day treatment with MP at a dose of 1 g i.v. once daily. Chemokine levels were measured by ELISA. Results: CXCL10 levels were significantly higher in the CSF of MS patients both during relapse (mean +/- SD, 298.2 +/- 143.8 pg/ml) and stable disease (323.7 +/- 183 pg/ml) in comparison with the control group (152.4 +/- 97.7 pg/ml; p < 0.001). CSF levels of CCL5 were significantly higher in relapsing MS patients (8.74 +/- 6.18 pg/ml) in comparison with stable MS patients (4.4 +/- 3.9 pg/ml, p = 0.005). CXCL11 levels of MS patients did not significantly differ from control values. There was no effect of MP therapy on serum levels of CCL5, CXCL10 and CXCL11. Conclusions: These observations suggest involvement of CXCL10 and CCL5 but not CXCL11 in the pathogenesis of MS. CCL5 may induce the recruitment of inflammatory cells in acute-stage MS.

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2: Cancer immunology, immunotherapy : CII, 2010 Aug 13,
Integrating individual functional moieties of CXCL10 and CXCL11 into a novel chimeric chemokine leads to synergistic antitumor effects: a strategy for chemokine-based multi-target-directed cancer therapy.

[Abstract]The complexity of tumor biology necessitates a multimodality approach that targets different aspects of tumor environment in order to generate the greatest benefit. IFN-inducible T cell alpha chemoattractant (ITAC)/CXCL11 and IFN-inducible protein 10 (IP10)/CXCL10 could exert antitumor effects with functional specificity and thus emerge as attractive candidates for combinatorial strategy. Disappointedly, a synergistic antitumor effect could not be observed when CXCL10 and CXCL11 were pooled together. In this regard, we seek to improve antitumor efficacy by integrating their individual functional moieties into a chemokine chimeric molecule, designated ITIP, which was engineered by substituting the N-terminal and N-loop region of CXCL10 with those of CXCL11. The functional properties of ITIP were determined by chemotaxis and angiogenesis assays. The antitumor efficacy was tested in murine CT26 colon carcinoma, 4T1 mammary carcinoma and 3LL lung carcinoma. Here we showed that ITIP not only exhibited respective functional superiority but strikingly promoted regression of established tumors and remarkably prolonged survival of mice compared with its parent chemokines, either alone or in combination. The chemokine chimera induced an augmented anti-tumor immunity and a marked decrease in tumor vasculature. Antibody neutralization studies indicated that CXCL10 and CXCL11 moieties of ITIP were responsible for anti-angiogenesis and chemotaxis in antitumor response, respectively. These results indicated that integrating individual functional moieties of CXCL10 and CXCL11 into a chimeric chemokine could lead to a synergistic antitumor effect. Thus, this integration strategy holds promise for chemokine-based multiple targeted therapy of cancer.

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3: The Journal of biological chemistry, 2010 Apr 2,
Characterization of the chemokine CXCl11 - heparin interaction suggests two different affinities for glycosaminoglycans.

[Abstract]Chemokines orchestrate the migration of leukocytes in the context of homeostasis and inflammation. In addition to interactions of chemokines with receptors on migrating cells, these processes require interactions of chemokines with glycosaminoglycans (GAGs) for cell surface localization. Most chemokines are basic proteins with Arg/Lys/His residue clusters functioning as recognition epitopes for GAGs. In this study we characterized the GAG-binding epitopes of the chemokine I-TAC/CXCL11. Four separate clusters of basic residues were mutated to alanine and tested for their ability to bind to GAGs in vitro and to activate the receptor, CXCR3. Mutation of a set of lysines in the C-terminal helix (the 50s cluster, 57KSKQAR62) along with K17, significantly impaired heparin binding in vitro identifying these residues as components of the dominant epitope. However, this GAG mutant retained near WT receptor binding affinity, and its ability to induce cell migration in vitro was only mildly perturbed. Nevertheless, the mutant was unable to induce cell migration in vivo establishing a requirement of CXCL11 for GAG-binding for in vivo function. These studies led to some interesting findings. First, CXCL11 exhibits conformational heterogeneity as evidenced by the doubling of peaks in its HSQC spectra. Second, it exhibits more than one affinity state for both heparin and CXCR3 which may be related to its structural plasticity. Finally, while the binding affinities of chemokines for GAGs are typically weaker than interactions with receptors, the high affinity GAG binding state of CXCL11 is comparable to typical receptor binding affinities suggesting some unique properties of this chemokine.

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4: Veterinary immunology and immunopathology, 2010 Mar 6, 51(2)
Expressed gene sequence and bioactivity of the IFNgamma-response chemokine CXCL11 of swine and cattle.

[Abstract]This report describes the cloning and characterization of expressed gene sequences of the swine and bovine interferon-gamma inducible chemokine CXCL11, or I-TAC, associated with type 1 T-helper immune responses, and affirmation of bioactivity of their yeast-expressed protein products. The coding regions of both cDNA sequences were 303 nucleotides in length; each is coded for four exons in the genome. The bovine coding region shared 82% and 70% homology with human and mouse CXCL11, respectively, and the swine coding region 84% and 72% homology, respectively. As expected the swine and bovine CXCL11 sequences showed less homology with other human and mouse C-X-C motif chemokine sequences. Each cDNA was cloned into plasmids and transfected into Pichia pastoris (yeast) and the resultant expressed protein purified. Biological activity of each purified chemokine was affirmed by chemotaxis assays. Both swine and bovine CXCL11 were chemotactic for mitogen and IL-2 stimulated peripheral blood mononuclear cells. This is the first report for bioactivity of this chemokine in livestock species. This work provides valuable new reagents for investigating basic immunity as well as vaccine and disease responses in swine and cattle, goals of the U.S. Veterinary Immune Reagent Network which supported this effort.

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5: The American journal of pathology, 2008 Sep, 173(3)
ELR-negative CXC chemokine CXCL11 (IP-9/I-TAC) facilitates dermal and epidermal maturation during wound repair.

[Abstract]In skin wounds, the chemokine CXCR3 receptor appears to play a key role in coordinating the switch from regeneration of the ontogenically distinct mesenchymal and epithelial compartments toward maturation. However, because CXCR3 equivalently binds four different ELR-devoid CXC chemokines (ie, PF4/CXCL4, IP-10/CXCL10, MIG/CXCL9, and IP-9/CXCL11), we sought to identify the ligand that coordinates epidermal coverage with the maturation of the underlying superficial dermis. Because CXCL11 (IP-9 or I-TAC) is produced by redifferentiating keratinocytes late in the regenerative phase when re-epithelialization is completed and matrix maturation ensues, we generated mice in which an antisense construct (IP-9AS) eliminated IP-9 expression during the wound-healing process. Both full and partial thickness excisional wounds were created and analyzed histologically throughout a 2-month period. Wound healing was impaired in the IP-9AS mice, with a hypercellular and immature dermis noted even after 60 days. Re-epithelialization was delayed with a deficient delineating basement membrane persisting in mice expressing the IP-9AS construct. Provisional matrix components persisted in the dermis, and the mature basement membrane components laminin V and collagen IV were severely diminished. Interestingly, the inflammatory response was not diminished despite IP-9/I-TAC being chemotactic for such cells. We conclude that IP-9 is a key ligand in the CXCR3 signaling system for wound repair, promoting re-epithelialization and modulating the maturation of the superficial dermis.

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6: Blood, 2008 Oct 1, 112(7)
Citrullination of CXCL10 and CXCL11 by peptidylarginine deiminase: a naturally occurring posttranslational modification of chemokines and new dimension of immunoregulation.

[Abstract]Interactions between chemokines and enzymes are vital in immunoregulation. Structural protein citrullination by peptidylarginine deiminase (PAD) has been associated with autoimmunity. In this report, we identified a novel naturally occurring posttranslational modification of chemokines, that is, the deimination of arginine at position 5 into citrulline of CXC chemokine ligand 10 (CXCL10) by rabbit PAD and human PAD2. Citrullination reduced (>/= 10-fold) the chemoattracting and signaling capacity of CXCL10 for CXC chemokine receptor 3 (CXCR3) transfectants; however, it did not affect CXCR3 binding. On T lymphocytes, though, citrullinated CXCL10 remained active but was again weaker than authentic CXCL10. PAD was also able to convert CXCL11, causing an impairment of CXCR3 signaling and T-cell activation, though less pronounced than for CXCL10. Similarly, receptor binding properties of CXCL11 were not altered by citrullination. However, deimination decreased heparin binding properties of both CXCL10 and CXCL11. Overall, chemokines are the first immune modulators reported of being functionally modified by citrullination. These data provide new structure-function dimensions for chemokines in leukocyte mobilization, disclosing an anti-inflammatory role for PAD. Additionally because citrullination has severe consequences for chemokine biology, this invites to reassess the involvement and impact of PAD and citrullinated peptides in inflammation, autoimmunity, and hematologic disorders.

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7: The Journal of biological chemistry, 2008 Jul 11, 283(28)
Matrix metalloproteinase processing of CXCL11/I-TAC results in loss of chemoattractant activity and altered glycosaminoglycan binding.

[Abstract]The CXCR3 chemokine receptor regulates the migration of Th1 lymphocytes and responds to three ligands: CXCL9/MIG, CXCL10/IP-10, and CXCL11/I-TAC. We screened for potential regulation of T cell responses by matrix metalloproteinase (MMP) processing of these important chemokines. The most potent of the CXCR3 ligands, CXCL11, was identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry as a substrate of the PMN-specific MMP-8, macrophage-specific MMP-12, and the general leukocyte MMP-9. The 73-amino acid residue CXCL11 is processed at both the amino and carboxyl termini to generate CXCL11-(5-73), -(5-63), and -(5-58) forms. NH2-terminal truncation results in loss of agonistic properties, as shown in calcium mobilization and chemotaxis experiments using CXCR3 transfectants and human T lymphocytes. Moreover, CXCL11-(5-73) is a CXCR3 antagonist and interestingly shows enhanced affinity to heparin. However, upon COOH-terminal truncation to position 58 there is loss of antagonist activity and heparin binding. Together this highlights an unexpected site for receptor interaction and that the carboxyl terminus is critical for glycosaminoglycan binding, an essential function for the formation of chemokine gradients in vivo. Hence, MMP activity might regulate CXCL11 tissue gradients in two ways. First, the potential of CXCL11-(5-73) to compete active CXCL11 from glycosaminoglycans might lead to the formation of an antagonistic haptotactic chemokine gradient. Second, upon further truncation, MMPs disperse the CXCL11 gradients in a novel way by proteolytic loss of a COOH-terminal GAG binding site. Hence, these results reveal potential new roles in down-regulating Th1 lymphocyte chemoattraction through MMP processing of CXCL11.

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8: Life sciences, 2008 Mar 12, 82(11-12)
Retinoic acid-inducible gene-I is induced by interferon-gamma and regulates CXCL11 expression in HeLa cells.

[Abstract]Retinoic acid-inducible gene-I (RIG-I) is a member of the DExH box family proteins, which have diverse roles in the regulation of gene expression and cellular functions. RIG-I is one of the factors regulated by interferon (IFN)-gamma and regarded as an intracellular signaling molecule for IFN-gamma. IFN-gamma is a major cytokine and also suggested to be involved in embryonal implantation and pregnancy. It is demonstrated that IFN-gamma stimulates endometrial epithelial cells to produce CXCL11, which is implicated in implantation. The aim of the present study was to investigate the effect of IFN-gamma on RIG-I expression in HeLa cells, a cell line derived from human uterine carcinoma. We found that RIG-I mRNA and protein were expressed in HeLa cells stimulated with IFN-gamma. The effect of IFN-gamma was observed in concentration- and time-dependent manners. The RNA interference against RIG-I resulted in the suppression of the IFN-gamma-induced CXCL11 expression. Immunohistochemical studies revealed the RIG-I expression in the normal human endometrium, suggesting a possible role of RIG-I in human reproductive organs.