Articles de revues : « CXCR2 receptor »

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Zhang, Jing, Shouguo Huang, Lini Quan, Qiu Meng, Haiyan Wang, Jie Wang et Jin Chen. « Determination of Potential Therapeutic Targets and Prognostic Markers of Ovarian Cancer by Bioinformatics Analysis ». BioMed Research International 2021 (19 mars 2021) : 1–13. http://dx.doi.org/10.1155/2021/8883800.

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This study is to study the expression of CXCRs in ovarian cancer tissues and their value in prognosis. The expressions of CXCR1-CXCR7 mRNA between ovarian tumor tissues and normal tissues and in different pathological types of ovarian tumor tissues were compared by ONCOMINE online tool. The relationship between the expression of CXCRs and clinical pathological staging was studied by GEPIA. Kaplan-Meier plotter online tool was used to analyze prognosis. Finally, GO and KEGG analyses and protein interaction network analysis were performed for CXCRs by the DAVID software to predict their function, and cBioPortal was used to identify the key functional genes. The expression of CXCR3/4/7 mRNA in ovarian cancer tissues was higher than that in normal ovarian tissues, and the expression of CXCR4 was the highest ( fold change = 306.413 , P < 0.05 ). The expression of CXCR1/2/3/4/7 mRNA in different pathological types of ovarian tumors was significantly different ( P < 0.05 ). Only CXCR5 expression level was associated with tumor staging. Survival analysis showed that high CXCR7 mRNA expression and low CXCR5/6 expression were associated with the shortening of overall survival. High CXCR4/7 expression and low CXCR5/6 expression were associated with the shortening of progression-free survival. High CXCR2/4 expression and low CXCR5/6 expression were closely related to the shortening of postprogressing survival. Protein interaction network analysis showed that GNB1, PTK2, MAPK1, PIK3CA, GNB4, GNA11, KNG1, and ARNT proteins were closely related to the CXC receptor family. CXCR3/4/7 are potential therapeutic targets, and CXCR2/4/5/6/7 are new markers for the prognosis of ovarian cancer.

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Korbecki, Jan, Klaudyna Kojder, Patrycja Kapczuk, Patrycja Kupnicka, Barbara Gawrońska-Szklarz, Izabela Gutowska, Dariusz Chlubek et Irena Baranowska-Bosiacka. « The Effect of Hypoxia on the Expression of CXC Chemokines and CXC Chemokine Receptors—A Review of Literature ». International Journal of Molecular Sciences 22, n^o 2 (15 janvier 2021) : 843. http://dx.doi.org/10.3390/ijms22020843.

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Hypoxia is an integral component of the tumor microenvironment. Either as chronic or cycling hypoxia, it exerts a similar effect on cancer processes by activating hypoxia-inducible factor-1 (HIF-1) and nuclear factor (NF-κB), with cycling hypoxia showing a stronger proinflammatory influence. One of the systems affected by hypoxia is the CXC chemokine system. This paper reviews all available information on hypoxia-induced changes in the expression of all CXC chemokines (CXCL1, CXCL2, CXCL3, CXCL4, CXCL5, CXCL6, CXCL7, CXCL8 (IL-8), CXCL9, CXCL10, CXCL11, CXCL12 (SDF-1), CXCL13, CXCL14, CXCL15, CXCL16, CXCL17) as well as CXC chemokine receptors—CXCR1, CXCR2, CXCR3, CXCR4, CXCR5, CXCR6, CXCR7 and CXCR8. First, we present basic information on the effect of these chemoattractant cytokines on cancer processes. We then discuss the effect of hypoxia-induced changes on CXC chemokine expression on the angiogenesis, lymphangiogenesis and recruitment of various cells to the tumor niche, including myeloid-derived suppressor cells (MDSCs), tumor-associated macrophages (TAMs), tumor-associated neutrophils (TANs), regulatory T cells (Tregs) and tumor-infiltrating lymphocytes (TILs). Finally, the review summarizes data on the use of drugs targeting the CXC chemokine system in cancer therapies.

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Konrad, F. M., et J. Reutershan. « CXCR2 in Acute Lung Injury ». Mediators of Inflammation 2012 (2012) : 1–8. http://dx.doi.org/10.1155/2012/740987.

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In pulmonary inflammation, recruitment of circulating polymorphonuclear leukocytes is essential for host defense and initiates the following specific immune response. One pathological hallmark of acute lung injury and acute respiratory distress syndrome is the uncontrolled transmigration of neutrophils into the lung interstitium and alveolar space. Thereby, the extravasation of leukocytes from the vascular system into the tissue is induced by chemokines that are released from the site of inflammation. The most relevant chemokine receptors of neutrophils are CXC chemokine receptor (CXCR) 1 and CXCR2. CXCR2 is of particular interest since several studies implicate a pivotal role of this receptor in development and promotion of numerous inflammatory disorders. CXCR2 gets activated by ELR+chemokines, including MIP-2, KC (rodents) and IL-8 (human). Since multiple ELR+CXC chemokines act on both receptors—CXCR1 and CXCR2—a pharmacologic agent blocking both receptors seems to be advantageous. So far, several CXCR1/2 antagonists have been developed and have been tested successfully in experimental studies. A newly designed CXCR1 and CXCR2 antagonist can be orally administered and was for the first time found efficient in humans. This review highlights the role of CXCR2 in acute lung injury and discusses its potential as a therapeutic target.

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Daniele, Simona, Simona Saporiti, Stefano Capaldi, Deborah Pietrobono, Lara Russo, Uliano Guerrini, Tommaso Laurenzi et al. « Functional Heterodimerization between the G Protein-Coupled Receptor GPR17 and the Chemokine Receptors 2 and 4 : New Evidence ». International Journal of Molecular Sciences 24, n^o 1 (23 décembre 2022) : 261. http://dx.doi.org/10.3390/ijms24010261.

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GPR17, a G protein-coupled receptor, is a pivotal regulator of myelination. Its endogenous ligands trigger receptor desensitization and downregulation allowing oligodendrocyte terminal maturation. In addition to its endogenous agonists, GPR17 could be promiscuously activated by pro-inflammatory oxysterols and chemokines released at demyelinating lesions. Herein, the chemokine receptors CXCR2 and CXCR4 were selected to perform both in silico modelling and in vitro experiments to establish their structural and functional interactions with GPR17. The relative propensity of GPR17 and CXCR2 or CXCR4 to form homo- and hetero-dimers was assessed by homology modelling and molecular dynamics (MD) simulations, and co-immunoprecipitation and immunoenzymatic assay. The interaction between chemokine receptors and GPR17 was investigated by determining receptor-mediated modulation of intracellular cyclic adenosine monophosphate (cAMP). Our data show the GPR17 association with CXCR2 or CXCR4 and the negative regulation of these interactions by CXCR agonists or antagonists. Moreover, GPR17 and CXCR2 heterodimers can functionally influence each other. In contrast, CXCR4 can influence GPR17 functionality, but not vice versa. According to MD simulations, all the dimers reached conformational stability and negative formation energy, confirming the experimental observations. The cross-talk between these receptors could play a role in the development of the neuroinflammatory milieu associated with demyelinating events.

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Uhl, Barbara, Katharina T. Prochazka, Katrin Pansy, Kerstin Wenzl, Johanna Strobl, Claudia Baumgartner, Marta M. Szmyra et al. « Distinct Chemokine Receptor Expression Profiles in De Novo DLBCL, Transformed Follicular Lymphoma, Richter’s Trans-Formed DLBCL and Germinal Center B-Cells ». International Journal of Molecular Sciences 23, n^o 14 (17 juillet 2022) : 7874. http://dx.doi.org/10.3390/ijms23147874.

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Chemokine receptors and their ligands have been identified as playing an important role in the development of diffuse large B-cell lymphoma (DLBCL), follicular lymphoma, and Richter syndrome (RS). Our aim was to investigate the different expression profiles in de novo DLBCL, transformed follicular lymphoma (tFL), and RS. Here, we profiled the mRNA expression levels of 18 chemokine receptors (CCR1–CCR9, CXCR1–CXCR7, CX3CR1 and XCR1) using RQ-PCR, as well as immunohistochemistry of seven chemokine receptors (CCR1, CCR4–CCR8 and CXCR2) in RS, de novo DLBCL, and tFL biopsy-derived tissues. Tonsil-derived germinal center B-cells (GC-B) served as non-neoplastic controls. The chemokine receptor expression profiles of de novo DLBCL and tFL substantially differed from those of GC-B, with at least 5-fold higher expression of 15 out of the 18 investigated chemokine receptors (CCR1–CCR9, CXCR1, CXCR2, CXCR6, CXCR7, CX3CR1 and XCR1) in these lymphoma subtypes. Interestingly, the de novo DLBCL and tFL exhibited at least 22-fold higher expression of CCR1, CCR5, CCR8, and CXCR6 compared with RS, whereas no significant difference in chemokine receptor expression profile was detected when comparing de novo DLBCL with tFL. Furthermore, in de novo DLBCL and tFLs, a high expression of CCR7 was associated with a poor overall survival in our study cohort, as well as in an independent patient cohort. Our data indicate that the chemokine receptor expression profile of RS differs substantially from that of de novo DLBCL and tFL. Thus, these multiple dysregulated chemokine receptors could represent novel clinical markers as diagnostic and prognostic tools. Moreover, this study highlights the relevance of chemokine signaling crosstalk in the tumor microenvironment of aggressive lymphomas.

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Coperchini, Francesca, Laura Croce, Michele Marinò, Luca Chiovato et Mario Rotondi. « Role of chemokine receptors in thyroid cancer and immunotherapy ». Endocrine-Related Cancer 26, n^o 8 (août 2019) : R465—R478. http://dx.doi.org/10.1530/erc-19-0163.

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Inflammation is currently regarded as an essential component of malignancies. It is now known that the tumor microenvironment may profoundly influence the biological behavior of cancer cells and ultimately the patient’s outcome. Chemokine and their receptor play a major role in determining the immune phenotype of the cells infiltrating the thyroid tumor microenvironment. Experimental evidence shows that both normal and cancer thyroid cells express specific chemokine receptors. The expression of at least some of these receptors exerts several biological effects, which influence the course of the disease. The present review article will take into account the role of the most studied chemokine receptors (CXCR1, CXCR2, CXCR3, CXCR4, CXCR7, DARC, CCR3, CCR6 and CCR7) in the context of thyroid cancer. This review will focus on current knowledge provided by in vitro and in vivo studies specifically performed on thyroid cancer including (i) expression of chemokine receptors in normal and cancer thyroid cells; (ii) role of chemokine receptors in affecting the biological behavior of thyroid tumors including the metastatic process; (iii) current knowledge about immunotherapies through targeting of chemokine receptors in thyroid cancer.

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Richardson, Micheler, Timothy Adekoya, Nikia Smith et Parag Kothari. « Opposite effects of CXCR1 and CXCR2 overexpression in prostate tumorigenesis ». Journal of Immunology 208, n^o 1_Supplement (1 mai 2022) : 178.12. http://dx.doi.org/10.4049/jimmunol.208.supp.178.12.

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Abstract Chemokines and their receptors play important role in tumor progression and metastasis. In prostate cancer (PCa), some members of the CXC chemokine receptor have been shown to enhance angiogenesis, proliferation and metastasis. In this study we assess the roles of the interleukin-8 (IL-8/CXCL8) receptors CXCR1 and CXCR2 in prostate tumorigenesis, using MDA PCa 2b and LNCaP cell lines. Our results show that overexpression of CXCR2 enhanced in-vitro cell proliferation, soft agar growth and in-vivo tumor xenograft in nude mice, whereas overexpression of CXCR1 inhibited cell proliferation and tumor growth, relative to control cells. CXCR1 cells showed decrease prostate specific antigen (PSA) expression whereas CXCR2 exhibited decrease androgen receptor (AR) expression. Interestingly, tumor lysates from CXCR1 cells displayed significant increase in ERK and AKT activation as well as chemokines production relative to control and CXCR2 tumors. CXCR1 tumors also exhibited a more mesenchymal phenotype, characterized by reduced E-Cadherin but increased N-Cadherin and Vimentin expression relative to CXCR2 or control tumors. Altogether, these results indicate that CXCR1 and CXCR2 may couple to distinct pathways to modulate prostate tumorigenesis. Supported by CA156735, MD012392

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Yildirim, Sedat, Frank Bautz, Andreas M. Boehmler, Lothar Kanz et Robert Möhle. « Regulation of CXCR1, CXCR2 and CXCR4 in Human Neutrophils : Potential Role in the Release from the Bone Marrow, Clearance of Senescent Cells, and Cell Function at Sites of Inflammation. » Blood 106, n^o 11 (16 novembre 2005) : 3068. http://dx.doi.org/10.1182/blood.v106.11.3068.3068.

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Abstract In the mouse model, it has been shown that the interleukin-8 (IL-8) receptor CXCR2 is involved in the release of mature neutrophils from the bone marrow into the circulation. When neutrophils age, upregulation of CXCR4 and downmodulation of CXCR2 result in homing and subsequent sequestration of senescent cells in the bone marrow. In our study, we observed a similar time-dependent (starting at 3 hrs., maximum at 12–18 hrs.) downregulation of CXCR2 in human neutrophils during aging in ex vivo culture, while expression of the second IL-8 receptor CXCR1, which is mainly responsible for the IL-8-induced chemotaxis, was unchanged. Furthermore, strong upregulation of CXCR4 was noted on the cell surface which could not solely be attributed to re-expression of internalized, intracellular receptors, as an increased amount of CXCR4 mRNA was detected by Northern blot analysis in these cells. The increase in CXCR4 expression was not influenced by inflammatory cytokines such as TNF and IL-1, as well as by IL-8 or G-CSF. Accordingly, SDF-1-induced transendothelial migration of aged neutrophils was 6-fold increased and even exceeded migration in response to IL-8. We conclude that also in human neutrophils, loss of CXCR2 and gain of CXCR4 expression on the cell surface may favor homing and sequestration of senescent cells in the bone marrow. At sites of inflammation however, retained expression of CXCR1 and increased expression of CXCR4 still allow a response of aged, pre-apoptotic neutrophils to the chemotactic mediators IL-8 and SDF-1, as the latter is not only released in the bone marrow, but also at sites of tissue damage and necrosis.

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Schmausser, Bernd, Christine Josenhans, Simon Endrich, Sebastian Suerbaum, Cassian Sitaru, Mindaugas Andrulis, Stephanie Brändlein, Peter Rieckmann, Hans Konrad Müller-Hermelink et Matthias Eck. « Downregulation of CXCR1 and CXCR2 Expression on Human Neutrophils by Helicobacter pylori : a New Pathomechanism in H. pylori Infection ? » Infection and Immunity 72, n^o 12 (décembre 2004) : 6773–79. http://dx.doi.org/10.1128/iai.72.12.6773-6779.2004.

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ABSTRACT In Helicobacter pylori gastritis, neutrophil activation and migration, which play central roles in the pathogenesis of the disease, are regulated by the neutrophil attractant chemokines interleukin 8 (IL-8) and Groα, whose secretion is induced by H. pylori. However, the modulation of the corresponding chemokine receptors CXCR1 and CXCR2 on human neutrophils under the influence of H. pylori has not been investigated. Incubation of neutrophils with cag + and cag deletion H. pylori strains resulted in a complete downregulation of the CXCR1 and the CXCR2 receptors after 0.5 h, as tested by fluorescence-activated cell sorter analysis, independent of the cag status. Downregulation of CXCR1 and CXCR2 seems to occur via receptor internalization and rapid degradation, as shown by confocal microscopy and immunoblotting. Neither the proinflammatory cytokines IL-8 and tumor necrosis factor alpha produced by the neutrophils themselves nor H. pylori lipopolysaccharide, which are the known regulators of these two chemokine receptors, was responsible for the downregulation. Reverse transcription-PCR analysis showed that CXCR1 and CXCR2 mRNAs of neutrophils were reduced at a later time than the CXCR1 and CXCR2 proteins. Moreover, cag + H. pylori strains induced significantly stronger downregulation of CXCR1 and CXCR2 mRNAs than the cag deletion mutant. Therefore, receptor protein and mRNA downregulation seem to be mediated by two independent mechanisms. Data obtained by immunohistochemistry suggested that downmodulation of CXCR1 and CXCR2 on neutrophils may also occur in vivo in the human stomach during H. pylori infection. Downregulation of CXCR1 and CXCR2 expression on neutrophils in H. pylori infection by H. pylori itself may represent a new mechanism of modulating neutrophil migration and activation in the gastric mucosa.

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Khandaker, Masud H., Gordon Mitchell, Luoling Xu, Joseph D. Andrews, Rajkumari Singh, Harry Leung, Joaquı́n Madrenas, Stephen S. G. Ferguson, Ross D. Feldman et David J. Kelvin. « Metalloproteinases Are Involved in Lipopolysaccharide– and Tumor Necrosis Factor-–Mediated Regulation of CXCR1 and CXCR2 Chemokine Receptor Expression ». Blood 93, n^o 7 (1 avril 1999) : 2173–85. http://dx.doi.org/10.1182/blood.v93.7.2173.

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Abstract The neutrophil-specific G-protein–coupled chemokine receptors, CXCR1 and CXCR2, bind with high affinity to the potent chemoattractant interleukin-8 (IL-8). The mechanisms of IL-8 receptor regulation are not well defined, although previous studies have suggested a process of ligand-promoted internalization as a putative regulatory pathway. Herein, we provide evidence for two distinct processes of CXCR1 and CXCR2 regulation. Confocal microscopy data showed a redistribution of CXCR1 expression from the cell surface of neutrophils to internal compartments after stimulation with IL-8, whereas stimulation with bacterial lipopolysaccharide (LPS) or tumor necrosis factor- (TNF-) did not induce CXCR1 internalization but instead mediated a significant loss of membrane-proximal CXCR1 staining intensity. To investigate whether proteolytic cleavage was the mechanism responsible for LPS- and TNF-–induced downmodulation of IL-8 receptors, we tested a panel of proteinase inhibitors. The downmodulation of CXCR1 and CXCR2 by LPS and TNF- was most dramatically inhibited by metalloproteinase inhibitors; 1,10-phenanthroline and EDTA significantly attenuated LPS- and TNF-–induced loss of CXCR1 and CXCR2 cell surface expression. Metalloproteinase inhibitors also blocked the release of CXCR1 cleavage fragments into the cell supernatants of LPS- and TNF-–stimulated neutrophils. In addition, while treatment of neutrophils with LPS and TNF- inhibited IL-8 receptor–mediated calcium mobilization and IL-8–directed neutrophil chemotaxis, both 1,10-phenanthroline and EDTA blocked these inhibitory processes. In contrast, metalloproteinase inhibitors did not affect IL-8–mediated downmodulation of CXCR1 and CXCR2 cell surface expression or receptor signaling. Thus, these findings may provide further insight into the mechanisms of leukocyte regulation during immunologic and inflammatory responses.

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Khandaker, Masud H., Gordon Mitchell, Luoling Xu, Joseph D. Andrews, Rajkumari Singh, Harry Leung, Joaquı́n Madrenas, Stephen S. G. Ferguson, Ross D. Feldman et David J. Kelvin. « Metalloproteinases Are Involved in Lipopolysaccharide– and Tumor Necrosis Factor-–Mediated Regulation of CXCR1 and CXCR2 Chemokine Receptor Expression ». Blood 93, n^o 7 (1 avril 1999) : 2173–85. http://dx.doi.org/10.1182/blood.v93.7.2173.407a06_2173_2185.

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The neutrophil-specific G-protein–coupled chemokine receptors, CXCR1 and CXCR2, bind with high affinity to the potent chemoattractant interleukin-8 (IL-8). The mechanisms of IL-8 receptor regulation are not well defined, although previous studies have suggested a process of ligand-promoted internalization as a putative regulatory pathway. Herein, we provide evidence for two distinct processes of CXCR1 and CXCR2 regulation. Confocal microscopy data showed a redistribution of CXCR1 expression from the cell surface of neutrophils to internal compartments after stimulation with IL-8, whereas stimulation with bacterial lipopolysaccharide (LPS) or tumor necrosis factor- (TNF-) did not induce CXCR1 internalization but instead mediated a significant loss of membrane-proximal CXCR1 staining intensity. To investigate whether proteolytic cleavage was the mechanism responsible for LPS- and TNF-–induced downmodulation of IL-8 receptors, we tested a panel of proteinase inhibitors. The downmodulation of CXCR1 and CXCR2 by LPS and TNF- was most dramatically inhibited by metalloproteinase inhibitors; 1,10-phenanthroline and EDTA significantly attenuated LPS- and TNF-–induced loss of CXCR1 and CXCR2 cell surface expression. Metalloproteinase inhibitors also blocked the release of CXCR1 cleavage fragments into the cell supernatants of LPS- and TNF-–stimulated neutrophils. In addition, while treatment of neutrophils with LPS and TNF- inhibited IL-8 receptor–mediated calcium mobilization and IL-8–directed neutrophil chemotaxis, both 1,10-phenanthroline and EDTA blocked these inhibitory processes. In contrast, metalloproteinase inhibitors did not affect IL-8–mediated downmodulation of CXCR1 and CXCR2 cell surface expression or receptor signaling. Thus, these findings may provide further insight into the mechanisms of leukocyte regulation during immunologic and inflammatory responses.

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Davies, Faith E., Mona H. Al Rayes, J. Anthony Child, Gareth J. Morgan et Andrew C. Rawstron. « The Bone Marrow Microenvironment Influences the Differential Chemokine Receptor Expression of Normal and Neoplastic Plasma Cells. » Blood 104, n^o 11 (16 novembre 2004) : 2353. http://dx.doi.org/10.1182/blood.v104.11.2353.2353.

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Abstract The expression of cytokines and chemokines are under control of several factors, including the bone marrow (BM) microenvironment. The aim of this work was to study the chemokine receptor expression on normal and neoplastic PCs and to investigate the relationship between the BM microenvironment and plasma cell behaviour. The study included 20 patients with reactive disorders or normal BM, 20 individuals with MGUS (monoclonal gammopathy of undetermined significance) and 19 patients with multiple myeloma at presentation. A large panel of chemokine receptor-specific antibodies directed against CCR1, CCR2, CCR3, CCR5, CCR6, CXCR1, CXCR2, CXCR3, CXCR4 and CXCR5 was characterized employing a four-colour flow cytometry approach. We demonstrate that normal and myeloma PCs have a specific chemokine receptor profile expressing 7/10 of the receptors studied. CCR2, CCR6, and CXCR1 showed decreased expression on myeloma PCs in comparison to normal PCs (average 3.3, 1.5 and 1.8-fold difference in expression level respectively). In contrast CXCR4 was upregulated on myeloma PCs on average 2.2-fold in comparison to normal PCs. There was no significant difference in expression between normal (CD19+) and neoplastic (CD19−) PCs from the same bone marrow environment in MGUS patients with respect to CCR6, CXCR1 and CXCR4. In contrast there was a significant difference in expression of CCR2 between CD19+ and CD19− PCs from the same BM (P=0.002). The level of expression on CD19− PCs was on average 1.6-fold lower than on their CD19+ counterparts (range 1.1 6.8-fold lower). In conclusion these data demonstrate that normal and myeloma PCs have a specific chemokine receptor profile. Myeloma PCs have a reduced level of some chemokine receptors compared to normal PCs which may account for their abnormal localization within the BM. Differences in expression of CXCR1, CXCR4, and CCR6 are not specific to the neoplastic process, as both normal and neoplastic plasma cells from the same marrow in MGUS patients show corresponding levels of expression. It is probable that feedback loops between neoplastic plasma cells and bone marrow stroma also influence normal plasma cell expression of these chemokine receptors. However, differences in CCR2 expression are not influenced by the marrow microenvironment, therefore downregulation of CCR2 expression is either a function of the neoplastic process or of the stage of differentiation of the originating neoplastic cell. Interfering with chemokines and their receptors which are related to the malignant transformation, particularly CCR2, may prove useful as adjunct to chemotherapy approaches.

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Lachota, Mieszko, Daniel Alfredo Palacios, Dennis Clement, Eivind Heggernes Ask, Hanna Julie Hoel, Merete Thune Wiiger, Marianna Vincenti, Magdalena Winiarska, Radoslaw Zagozdzon et Karl-Johan Malmberg. « Innate-like Chemokine Receptor Profile and Migratory Behaviour By Terminally Differentiated and Educated NK Cells ». Blood 136, Supplement 1 (5 novembre 2020) : 24–25. http://dx.doi.org/10.1182/blood-2020-140944.

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Natural Killer (NK) cells play an essential role in cancer surveillance and have a unique capability of spontaneous cytotoxicity against cancer cells. The human NK cell repertoire is functionally diversified through a tightly regulated differentiation process characterized by an early transition from CD56bright to CD56dim NK cells, followed by coordinated changes in expression of inhibitory receptors, including NKG2A and killer cell immunoglobulin-like receptors (KIR). The acquisition of self HLA class I binding KIRs during NK cell differentiation tunes the cytotoxic potential of NK cells in a process termed education, characterized by increased loading of granzyme B in dense core granules. Although NK cell differentiation and education are critical determinants of the functional potential of the cell, little is known about how these events shape the migratory behavior of NK cells. To mediate appropriate and directed immune response against cancer, NK cells must be capable of migration to the tumor site. This process is mediated by chemokines, which guide cell migration by binding to their specific receptors. For example, in multiple myeloma, CXCR3 and CCR5 ligands (MIG, IP-10, and MIP-1a) are significantly upregulated in the bone marrow compared to healthy controls, affecting the composition of immune cells in the tumor microenvironment. In order to delineate the homing patterns of distinct NK cell subsets, we used high-dimensional flow cytometry combined with functional assays to map the NK cell chemokine receptor expression and migratory behavior. We screened resting and cytokine/feeder cell stimulated peripheral blood NK cells for the expression of a panel of 20 chemokine receptors (A). Based on CD56, CD57, NKG2A, and KIR expression, NK cells were divided into 6 phenotypically and functionally distinct subsets that were ordered according to their differentiation status (B). We found that the expression of CX3CR1, CXCR1, CXCR2, and CMKLR1 gradually increased during differentiation, whereas the expression of CXCR3, CCR7, and CCR5 was lower in more differentiated NK cells. CXCR4, CCR4, and CCR2 expression was relatively uniform across all subsets. Interestingly, CCR1 and CXCR6 were expressed mainly on less differentiated NKG2A+ CD56dim NK cells (B). Next, we stratified the chemokine receptor expression on mature KIR+ NK cells based on the expression of self (educated) or non-self KIR (uneducated). Educated NK cells expressed CXCR1, CX3CR1, CCR5, and CMKLR1 at higher levels than the uneducated NK cells. Conversely, CXCR3 was expressed at lower levels on educated NK cells (C). No difference was observed for CXCR2 expression. To determine whether the observed differences in chemokine receptor expression translate into altered chemokine responsiveness between the subsets, we combined the transwell system with multicolor flow cytometry. We found that the chemokine-induced migration capability of NK cells correlated closely with the expression level of corresponding chemokine receptor, leading to subset specific responses to various chemokine gradients (D). The present results show that peripheral blood NK cell chemokine receptor profile changes in a coordinated fashion during NK cell differentiation and is further influenced by the expression of self-specific KIR. Interestingly, receptors which expression declines during NK cell differentiation (CCR5, CCR7, and CXCR3) are commonly associated with adaptive T cell responses to viruses, whereas receptors that are upregulated along the differentiation axis (CXCR1, CXCR2, CX3CR1, CMKLR1) are typical for neutrophils and macrophages as a part of the innate immune response. Thus, our results suggest that NK cell differentiation and education processes together shape the NK cell migratory capabilities to promote homing of the most functional NK cell subsets to the site of inflammation and serve as the first line of defense in the immune response to pathogens and tumors. Figure Disclosures Malmberg: Fate Therapeutics: Consultancy, Patents & Royalties; Vycellix: Membership on an entity's Board of Directors or advisory committees.

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Lima, Margarida, Magdalena Leander, Marlene Santos, Ana Helena Santos, Catarina Lau, Maria Luís Queirós, Marta Gonçalves et al. « Chemokine Receptor Expression on Normal Blood CD56+NK-Cells Elucidates Cell Partners That Comigrate during the Innate and Adaptive Immune Responses and Identifies a Transitional NK-Cell Population ». Journal of Immunology Research 2015 (2015) : 1–18. http://dx.doi.org/10.1155/2015/839684.

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Studies of chemokine receptors (CKR) in natural killer- (NK-) cells have already been published, but only a few gave detailed information on its differential expression on blood NK-cell subsets. We report on the expression of the inflammatory and homeostatic CKR on normal bloodCD56+lowCD16+andCD56+high CD16-/+lowNK-cells. ConventionalCD56+lowandCD56+highNK-cells present in the normal PB do express CKR for inflammatory cytokines, although with different patternsCD56+lowNK-cells are mainly CXCR1/CXCR2+and CXCR3/CCR5−/+, whereas mostlyCD56+highNK-cells are CXCR1/CXCR2−and CXCR3/CCR5+. Both NK-cell subsets have variable CXCR4 expression and are CCR4−and CCR6−. The CKR repertoire of theCD56+lowNK-cells approaches to that of neutrophils, whereas the CKR repertoire of theCD56+highNK-cells mimics that of Th1+T cells, suggesting that these cells are prepared to migrate into inflamed tissues at different phases of the immune response. In addition, we describe a subpopulation of NK-cells with intermediate levels of CD56 expression, which we namedCD56+intNK-cells. These NK-cells are CXCR3/CCR5+, they have intermediate levels of expression of CD16, CD62L, CD94, and CD122, and they are CD57−and CD158a−. In view of their phenotypic features, we hypothesize that they correspond to a transitional stage, between the well-knownCD56+highandCD56+lowNK-cells populations.

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Inngjerdingen, Marit, Bassam Damaj et Azzam A. Maghazachi. « Expression and regulation of chemokine receptors in human natural killer cells ». Blood 97, n^o 2 (15 janvier 2001) : 367–75. http://dx.doi.org/10.1182/blood.v97.2.367.

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Abstract Using flow cytometric and RNase protection assays, this study examined the expression of chemokine receptors in nonactivated natural killer (NK) cells and compared this expression with NK cells activated with interleukin (IL)-2, which either adhered to plastic flasks (AD) or did not adhere (NA). None of the NK cell subsets expressed CXCR2, CXCR5, or CCR5. The major differences between these cells include increased expression of CXCR1, CCR1, CCR2, CCR4, CCR8, and CX3CR1 in AD when compared to NA or nonactivated NK cells. The chemotactic response to the CXC and CC chemokines correlated with the receptor expression except that all 3 populations responded to GRO-α, despite their lack of CXCR2 expression. Pretreatment of these cells with anti-CXCR2 did not inhibit the chemotactic response to GRO-α. In addition, nonactivated and NA cells responded to fractalkine, although they lack the expression of CX3CR1. This activity was not inhibited by anti-CX3CR1. Viral macrophage inflammatory protein (vMIP)-I, I-309, and TARC competed with the binding of 125I-309 to AD cells with varying affinities. Transforming growth factor (TGF)-β1 but not any other cytokine or chemokine examined including interferon (IFN)-γ, MIP-3β, macrophage-derived chemokine (MDC), thymus and activation-regulated chemokine (TARC) or I-309, up-regulated the expression of CXCR3 and CXCR4 on NK cell surface. This is correlated with increased chemotaxis of NK cells treated with TGF-β1 toward stromal cell–derived factor (SDF)-1α and interferon-inducible protein-10 (IP-10). Messenger RNA for lymphotactin, RANTES, MIP-1α, and MIP-1β, but not IP-10, monocyte chemotactic protein (MCP)-1, IL-8, or I-309 was expressed in all 3 NK cell subsets. Our results may have implications for the dissemination of NK cells at the sites of tumor growth or viral replication.

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Fan, Guo-Huang, Lynne A. Lapierre, James R. Goldenring, Jiqing Sai et Ann Richmond. « Rab11-Family Interacting Protein 2 and Myosin Vb Are Required for CXCR2 Recycling and Receptor-mediated Chemotaxis ». Molecular Biology of the Cell 15, n^o 5 (mai 2004) : 2456–69. http://dx.doi.org/10.1091/mbc.e03-09-0706.

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Agonist-stimulated internalization followed by recycling to the cell membrane play an important role in fine-tuning the activity of chemokine receptors. Because the recycling of chemokine receptors is critical for the reestablishment of the cellular responsiveness to ligand, it is crucial to understand the mechanisms underlying the receptor recycling and resensitization. In the present study, we have demonstrated that the chemokine receptor CXCR2 associated with myosin Vb and Rab11-family interacting protein 2 (FIP2) in a ligand-dependent manner. Truncation of the C-terminal domain of the receptor did not affect the association, suggesting that the interactions occur upstream of the C terminus of CXCR2. After ligand stimulation, the internalized CXCR2 colocalized with myosin Vb and Rab11-FIP2 in Rab11a-positive vesicles. The colocalization lasted for ∼2 h, and little colocalization was observed after 4 h of ligand stimulation. CXCR2 also colocalized with myosin Vb tail or Rab11-FIP2 (129–512), the N-terminal–truncated mutants of myosin Vb and Rab11-FIP2, respectively, but in a highly condensed manner. Expression of the enhanced green fluorescent protein-tagged myosin Vb tail significantly retarded the recycling and resensitization of CXCR2. CXCR2 recycling was also reduced by the expression Rab11-FIP2 (129–512). Moreover, expression of the myosin Vb tail reduced CXCR2- and CXCR4-mediated chemotaxis. These data indicate that Rab11-FIP2 and myosin Vb regulate CXCR2 recycling and receptor-mediated chemotaxis and that passage of internalized CXCR2 through Rab11a-positive recycling system is critical for physiological response to a chemokine.

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Berg, Christian, Michael J. Wedemeyer, Motiejus Melynis, Roman R. Schlimgen, Lasse H. Hansen, Jon Våbenø, Francis C. Peterson, Brian F. Volkman, Mette M. Rosenkilde et Hans R. Lüttichau. « The non-ELR CXC chemokine encoded by human cytomegalovirus UL146 genotype 5 contains a C-terminal β-hairpin and induces neutrophil migration as a selective CXCR2 agonist ». PLOS Pathogens 18, n^o 3 (10 mars 2022) : e1010355. http://dx.doi.org/10.1371/journal.ppat.1010355.

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Human cytomegalovirus (HCMV) is a major pathogen in immunocompromised patients. The UL146 gene exists as 14 diverse genotypes among clinical isolates, which encode 14 different CXC chemokines. One genotype (vCXCL1GT1) is a known agonist for CXCR1 and CXCR2, while two others (vCXCL1GT5 and vCXCL1GT6) lack the ELR motif considered crucial for CXCR1 and CXCR2 binding, thus suggesting another receptor targeting profile. To determine the receptor target for vCXCL1GT5, the chemokine was probed in a G protein signaling assay on all 18 classical human chemokine receptors, where CXCR2 was the only receptor being activated. In addition, vCXCL1GT5 recruited β-arrestin in a BRET-based assay and induced migration in a chemotaxis assay through CXCR2, but not CXCR1. In contrast, vCXCL1GT1 stimulated G protein signaling, recruited β-arrestin and induced migration through both CXCR1 and CXCR2. Both vCXCL1GT1 and vCXCL1GT5 induced equally potent and efficacious migration of neutrophils, and ELR vCXCL1GT4 and non-ELR vCXCL1GT6 activated only CXCR2. In contrast to most human chemokines, the 14 UL146 genotypes have remarkably long C-termini. Comparative modeling using Rosetta showed that each genotype could adopt the classic chemokine core structure, and predicted that the extended C-terminal tail of several genotypes (including vCXCL1GT1, vCXCL1GT4, vCXCL1GT5, and vCXCL1GT6) forms a novel β-hairpin not found in human chemokines. Secondary NMR shift and TALOS+ analysis of vCXCL1GT1 supported the existence of two stable β-strands. C-terminal deletion of vCXCL1GT1 resulted in a non-functional protein and in a shift to solvent exposure for tryptophan residues likely due to destabilization of the chemokine fold. The results demonstrate that non-ELR chemokines can activate CXCR2 and suggest that the UL146 chemokines have unique C-terminal structures that stabilize the chemokine fold. Increased knowledge of the structure and interaction partners of the chemokine variants encoded by UL146 is key to understanding why circulating HCMV strains sustain 14 stable genotypes.

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Horuk, R., A. W. Martin, Z. Wang, L. Schweitzer, A. Gerassimides, H. Guo, Z. Lu et al. « Expression of chemokine receptors by subsets of neurons in the central nervous system. » Journal of Immunology 158, n^o 6 (15 mars 1997) : 2882–90. http://dx.doi.org/10.4049/jimmunol.158.6.2882.

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Abstract IL-8 is expressed by activated and neoplastic astrocytes and enhances the survival of hippocampal neurons in vitro. Since mRNA encoding chemokine receptors have been demonstrated in brain, the expression of chemokine receptors by specific cell types in anatomic regions of the central nervous system (CNS) was investigated. Archival tissues from various regions of the CNS were stained with specific mAbs to the Duffy Ag/receptor for chemokines, a promiscuous receptor that binds selected chemokines; the specific receptor for IL-8 (CXCR1); and the receptor (CXCR2) shared by IL-8 and melanoma growth stimulatory activity. The Duffy Ag/receptor for chemokines was expressed exclusively by Purkinje cells in the cerebellum. Chemokine binding and radioligand cross-linking confirmed the presence of a high affinity, promiscuous chemokine receptor in the cerebellum. Although CXCR1 was not expressed in the CNS, CXCR2 was expressed at high levels by subsets of projection neurons in diverse regions of the brain and spinal cord, including the hippocampus, dentate nucleus, pontine nuclei, locus coeruleus, and paraventricular nucleus, and in the anterior horn, interomediolateral cell column, and Clarke's column of the spinal cord. Fibers that express CXCR2 included those in the superior cerebellar peduncle and the substantia gelatinosa. Immunohistochemical analysis of the involved brain tissues from patients with Alzheimer's disease revealed expression of CXCR2 in the neuritic portion of plaques surrounding deposits of amyloid. These data suggest that chemokines may play a role in reactive processes in normal neuronal function and neurodegenerative disorders.

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Tarnowski, Maciej, Rui Liu, Joanna Tarnowska, Janina Ratajczak, Robert Mitchell, Mariusz Z. Ratajczak et Magdalena Kucia. « Novel Evidence That the Small Chemokine Macrophage Migration Inhibitory Factor (MIF) Is Highly Secreted by Human Rhabdomyosarcomas, Activates Both SDF-1–binding Receptors, CXCR4 and CXCR7, and Unexpectedly Inhibits Recruitment of Stromal Cells to the Growing Tumor. » Blood 116, n^o 21 (19 novembre 2010) : 3849. http://dx.doi.org/10.1182/blood.v116.21.3849.3849.

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Abstract Abstract 3849 Rhabdomyosarcoma (RMS) is the most common soft-tissue sarcoma of adolescents and children and frequently infiltrates the bone marrow (BM) to the degree that it mimics acute lymphoblastic leukemia. Here we show that human RMS cells highly express and secrete the small chemokine, macrophage migration inhibitory factor (MIF). MIF overexpression has been observed in several tumors and is implicated in oncogenic transformation and tumor progression. MIF activates CXCR2 and CD74 receptors, and surprisingly, as recently reported, may also bind to the stromal-derived factor-1 (SDF-1)–binding receptor CXCR4 (Nat Med 2007;13:587). Here we report that RMS-secreted MIF i) induces phosphorylation of MAPKp42/44 and AKT, ii) stimulates RMS cell adhesion, and iii) enhances tumor vascularization. Furthermore, since RMS cells employed in our studies do not express CXCR2 and CD74 receptors, the biological effects of MIF on RMS cells depend on its interaction with CXCR4. Moreover, as we report here for the first time, receptor internalization/binding studies reveal that MIF may also engage another SDF-1–binding receptor (CXCR7) as well. Since bone marrow fibroblasts highly express the MIF-binding receptor CXCR2, we became interested in the potential role of the MIF-mediated interaction between RMS and stromal cells and, to our surprise, observed that RMS-secreted MIF decreases recruitment of stromal fibroblasts to expanding sarcomas. In support of this finding, downregulation of MIF in RMS cells inoculated into immunodeficient mice lead to formation of larger tumors that displayed higher stromal-cell support. Based on these observations, we postulate that MIF is an important autocrine/paracrine factor that stimulates both CXCR4 and CXCR7 receptors to enhance the adhesiveness of RMS cells. We also envision that MIF in those situations when it is locally secreted by a growing tumor, may desensitize CXCR4 and CXCR7 receptors expressed on the tumor cells and thus prevents their responsiveness to SDF-1 secreted at potential future sites of metastasis and thereby prevents egress of cancer cells into the circulation. On the other hand, despite its obvious pro-angiopoietic effects, MIF inhibits recruitment of stromal cells to the growing tumor. This MIF-mediated impaired recruitment of stromal elements significantly slows down as evidenced by our in vivo xenograft studies tumor growth/expansion. Based on this, we suggest that therapeutic inhibition of MIF in expanding solid tumors may accelerate both metastasis and tumor growth. Thus, the potential application of MIF inhibitors for treatment of MIF-secreting tumors should be reconsidered. Disclosures: No relevant conflicts of interest to declare.

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Parenty, Geraldine, Shirley Appelbe et Graeme Milligan. « CXCR2 chemokine receptor antagonism enhances DOP opioid receptor function via allosteric regulation of the CXCR2–DOP receptor heterodimer ». Biochemical Journal 412, n^o 2 (14 mai 2008) : 245–56. http://dx.doi.org/10.1042/bj20071689.

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Opioid agonists have a broad range of effects on cells of the immune system, including modulation of the inflammatory response, and opioid and chemokine receptors are co-expressed by many white cells. Hetero-oligomerization of the human DOP opioid and chemokine CXCR2 receptors could be detected following their co-expression by each of co-immunoprecipitation, three different resonance energy transfer techniques and the construction of pairs of individually inactive but potentially complementary receptor G-protein α subunit fusion proteins. Although DOP receptor agonists and a CXCR2 antagonist had no inherent affinity for the alternative receptor when either receptor was expressed individually, use of cells that expressed a DOP opioid receptor construct constitutively, and in which expression of a CXCR2 receptor construct could be regulated, demonstrated that the CXCR2 antagonist enhanced the function of DOP receptor agonists only in the presence of CXCR2. This effect was observed for both enkephalin- and alkaloid-based opioid agonists, and the effective concentrations of the CXCR2 antagonist reflected CXCR2 receptor occupancy. Entirely equivalent results were obtained in cells in which the native DOP opioid receptor was expressed constitutively and in which expression of the isolated CXCR2 receptor could be induced. These results indicate that a CXCR2 receptor antagonist can enhance the function of agonists at a receptor for which it has no inherent direct affinity by acting as an allosteric regulator of a receptor that is a heterodimer partner for the CXCR2 receptor. These results have novel and important implications for the development and use of small-molecule therapeutics.

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Khandaker, Masud H., Luoling Xu, Rahbar Rahimpour, Gordon Mitchell, Mark E. DeVries, J. Geoffrey Pickering, Sharwan K. Singhal, Ross D. Feldman et David J. Kelvin. « CXCR1 and CXCR2 Are Rapidly Down-Modulated by Bacterial Endotoxin Through a Unique Agonist-Independent, Tyrosine Kinase-Dependent Mechanism ». Journal of Immunology 161, n^o 4 (15 août 1998) : 1930–38. http://dx.doi.org/10.4049/jimmunol.161.4.1930.

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Abstract The expression of the seven-transmembrane domain chemokine receptors CXCR1 and CXCR2 modulates neutrophil responsiveness to the chemoattractant IL-8 and a number of closely related CXC chemokines. In the present study, we investigated the mechanism by which bacterial LPS induces the down-modulation of IL-8 responsiveness and CXCR1 and CXCR2 expression on human neutrophils. Treating neutrophils with LPS reduced IL-8R expression to 55 ± 5% of the control within 30 min and to 23 ± 2% within 1 h of stimulation. Furthermore, this down-modulation could not be attributed to increased concentrations of IL-8, TNF-α, or IL-1β, since ELISA studies indicated that LPS-stimulated neutrophils did not release detectable amounts of these proteins before 2 h poststimulation. The tyrosine kinase (TK) inhibitors genistein and herbimycin A attenuated the LPS-mediated down-modulation of CXCR1 and CXCR2, indicating that the activation of a TK is required for LPS to mediate its effect. The effect of LPS on receptor expression paralleled the hyperphosphorylation of the protein TK p72syk. Although IL-8 induced a comparable down-modulation of CXCR1 and CXCR2, TK inhibitors did not attenuate this effect. These studies provide the first evidence of an agonist-independent, TK-dependent pathway of chemokine receptor regulation by endotoxin.

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Wenzl, Kerstin, Katharina Troppan, Alexander JA Deutsch, Werner Linkesch, Peter Neumeister et Christine Beham-Schmid. « Distinct Chemokine Receptor Profile In Chronic Lymphocytic Leukaemia and Richter Transformed Diffuse Large B Cell Lymphomas Compared To Germinal Center B Cells and De Novo Diffuse Large B Cell Lymphomas ». Blood 122, n^o 21 (15 novembre 2013) : 4852. http://dx.doi.org/10.1182/blood.v122.21.4852.4852.

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Abstract Chemokine receptors are G-protein-coupled cell surface receptors, which dissociate upon activation by their ligands and cause downstream signaling. Recently, several studies have revealed the crucial contribution of chemokine receptors and their ligands in normal B-cell differentiation and development of hematopoietic malignancies. The Richter syndrome (RS) represents the clinico-pathologic transformation of chronic lymphocytic leukaemia (CLL) to an aggressive lymphoma, most commonly diffuse large B-cell lymphoma (DLBCL). Due to the lack of knowledge on the chemokine receptors in RS, we aimed to investigate their expression profile in Richter syndrome patients. Therefore, we investigated the mRNA expression levels of 18 known chemokine receptors (CCR1-CCR9, CXCR1-CXCR7, XCR1, CX3CR1) by using semi-quantitative real time PCR on seven samples of paired (CLL and transformed DLBCL) RS samples, and six samples of de novo DLBCL, additionally four CLL samples –all of them transformed into DLBCL-, and eight transformed DLBCL samples –all of them originated from CLL- were included. Four samples of peripheral B cells and four samples of germinal center B cells (GCB) served as non-neoplastic controls. 11 out of 18 chemokine receptors were differentially expressed in CLL (RL) and transformed DLBCL originated from CLL (RH) compared to GCBs. RL exhibited an at least 15-fold higher expression of CCR2, CCR4, CCR7, CXCR3, and XCR1, as well as a de novo expression of CCR3, CCR8, CXCR1, CXCR2, and CX3CR1 compared to GCB. Additionally to these chemokine receptors, CCR1 also showed significant higher expression levels comparing GCB and RH samples. Only one chemokine receptor was found to be differentially expressed in our seven paired RS samples: CCR6 showed a trend of up-regulation in CLL components. Interestingly, the transformed DLBCL originated from CLL were characterized by a significant up-regulation of six chemokine receptors (CCR3, CCR7, CXCR1, CXCR3, CXCR4, and CX3CR1) and a down-regulation of CCR5 compared to DLBCL. Our data indicate that the chemokine receptor expression profile of CLL and transformed DLBCL, originated from CLL samples, differs substantially from those of non neoplastic germinal center B cells and de novo DLBCL, suggesting other cellular origin and an impact on more aggressive clinical course of Richter syndrome patients. Hence, these multiple deregulated CC and CXC receptor might serve as useful prognostic tool to separate high malignant Richter syndrome from de novo DLBCL. Disclosures: No relevant conflicts of interest to declare.

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Weisel, Katja C., Frank Bautz, Gabriele Seitz, Sedat Yildirim, Lothar Kanz et Robert Möhle. « Modulation of CXC Chemokine Receptor Expression and Function in Human Neutrophils during Aging In Vitro Suggests a Role in Their Clearance from Circulation ». Mediators of Inflammation 2009 (2009) : 1–8. http://dx.doi.org/10.1155/2009/790174.

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In mice, differential regulation of CXC chemokine receptor expression in circulating polymorphonuclear neutrophils (PMNs) undergoing senescence results in homing to the bone marrow. However, the role of this compartment and of the chemokine receptor CXCR4 is still under discussion, and only scarce data exist about CXCR4 function in human PMN. In our study, we provide evidence that also in human neutrophils, expression (cell surface and mRNA), chemotactic and signaling functions of the homing-related chemokine receptor CXCR4 are upregulated during aging in vitro, independent of addition of stimulatory cytokines (TNF, IL-1, IL-8, G-CSF). In contrast, interleukin-8 receptors are downmodulated (CXCR2) or remain unchanged (CXCR1), suggesting that human PMNs undergoing senescence acquire a phenotype that impairs inflammatory extravasation and favors homing to the bone marrow or other tissues involved in sequestration. Partially retained responsiveness to interleukin-8 may be important for neutrophil function when senescence occurs after extravasation in inflamed tissues.

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Ngo, Hai, Evdoxia Hatjiharissi, Xavier Leleu, Judith Runnels, Anne-Sophie Moreau, Xiaoying Jia, Garrett O’Sullivan et al. « The CXCR4/SDF-1 Axis Regulates Migration and Adhesion in Waldenstrom Macroglobulinemia. » Blood 108, n^o 11 (1 novembre 2006) : 2418. http://dx.doi.org/10.1182/blood.v108.11.2418.2418.

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Abstract Background: Waldenstrom Macroglobulinemia (WM) is characterized by widespread involvement of the bone marrow (BM), and lymphadenopathy in 20% of the patients, implying continuous trafficking of WM cells into and out of the BM and lymph nodes. The normal process of B-cell homing is regulated by cytokines, chemokines, and adhesion molecules. One of the most extensively studied chemokines in migration is stromal derived factor SDF-1 and its receptor CXCR4. Here we study the role of chemokine receptors, and the SDF-1/CXCR4 axis on migration and adhesion in WM. Methods: Flow cytometry for CXC and CC chemokine receptors (CXCR1, CXCR2, CXCR3, CXCR4, CXCR5, CCR2, CCR4, CCR5, CCR6 and CCR7), and adhesion molecules (VLA-4 and LFA-1) on WM cell lines (BCWM.1 and WM-WSU) and patient samples was performed. Migration was determined using the transwell migration assay (Costar, NY). Cells were placed in the upper chambers of the migration assay with 1% FCS medium in the presence of serial concentrations of SDF-1 in the lower chambers. After 4 hours of incubation, cells that migrated to the lower chambers were counted. Similarly, adhesion was determined using an adhesion assay (EMD Biosciences, San Diego, CA) with 96-well plated coated with fibronectin. Immunoblotting for proteins downstream of CXCR4 was performed. The CXCR4 inhibitor AMD3100 (10–100uM, Sigma, MO) and Gi protein inhibitor pertussis toxin PTX (10–200ng/ml, Sigma, MO) were used to inhibit CXCR4 signaling. Results: The following chemokine receptors were expressed on patient CD19+WM cells with over 30% expression: CXCR1 (mean 60%), CXCR2 (mean 47%), CXCR4 (mean 47%), CXCR5 (mean 69%), CCR4 (mean 54%) and CCR6 (mean 61%). Similar expression was observed on WM cell lines. We next determined the effect of SDF-1 on migration and signaling pathways in WM. SDF-1 (10–100nM) induced migration in a bell-shaped curve with 30nM inducing maximum migration (110% compared to control). SDF-1 30nM induced a rapid activation of signaling pathways downstream of CXCR4 including pERK1/2, pAKT, and pPKC at 1 min, with maximum activation at 5min. The CXCR4 inhibitor AMD3100 inhibited migration of BCWM.1 in the presence of 30nM SDF-1, with AMD3100 10uM inhibiting migration at 59% of control, and 20 to 50uM leading to a plateau in inhibition of migration at 54% of control. AMD3100 inhibited pERK and pPKC activation, downstream of CXCR4 in a dose-dependent fashion. Similar results were observed using PTX, with inhibition of migration of WM cells at 50% compared to control. To determine the role of SDF-1 on adhesion, we first demonstrated that WM cells from patients and cell lines expressed high levels of surface VLA-4 expression (mean 95% surface expression). WM cells had an increase in adhesion to fibronectin (VLA-4 ligand) compared to BSA control. AMD3100 10uM inhibited adhesion to fibronectin (63 % of control), indicating that the SDF-1/CXCR4 axis regulates adhesion. Conclusion: CXCR4 is highly expressed on WM cells and regulates migration and adhesion, indicating a potential role in regulating WM trafficking into the BM and lymph nodes. These studies provide the preclinical framework to study CXCR4 inhibitors in the regulation of homing and adhesion in WM.

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Eash, Kyle J., Adam M. Greenbaum, Priya Gopalan, George A. Diaz et Daniel C. Link. « CXCR2 Signals Act in Concert with CXCR4 to Regulate Neutrophil Release From the Bone Marrow. » Blood 114, n^o 22 (20 novembre 2009) : 235. http://dx.doi.org/10.1182/blood.v114.22.235.235.

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Abstract Abstract 235 Truncation mutations of CXCR4 that cause increased receptor signaling are responsible for most cases of WHIM (warts, hypogammaglobulinemia, infections, myelokathexis) syndrome, which is characterized by the retention of mature neutrophils in the bone marrow despite peripheral neutropenia. This observation and others have established CXCR4 as a key regulator of neutrophil release from the bone marrow. However, it is unclear how modulation of neutrophil CXCR4 signaling is linked to their migration toward the vascular endothelium and subsequent entry into the circulation. Therefore, the question of whether neutrophil egress from the bone marrow is a passive, random process or actively directed and what (if any) signals regulate it remains unanswered. We recently analyzed a myelokathexis pedigree and discovered homozygous, loss-of-function mutations in CXCR2. Based on these observations, we developed a “tug-of-war” model in which opposing chemokine gradients, specifically release-inducing CXCR2 signals and retention-promoting CXCR4 signals, act antagonistically to regulate neutrophil release from the bone marrow. To test this model, we analyzed neutrophil trafficking in CXCR2−/− mice. These mice have a well-characterized defect in neutrophil emigration from the blood to sites of inflammation, leading to chronic subclinical infection and the systemic release of cytokines that stimulate granulopoiesis. To circumvent these potentially confounding effects, we generated mixed bone marrow chimeras reconstituted with a 1:1 ratio of wild-type and CXCR2−/− bone marrow. As expected, approximately 50% (46 ± 4%) of circulating B cells were derived from CXCR2−/− cells. In contrast, a significant decrease in the proportion of CXCR2−/− neutrophils in the blood was observed (23 ± 4%; P < 0.001). Consistent with a myelokathexis phenotype, there was a relative accumulation of mature CXCR2−/− neutrophils in the bone marrow (47 ± 9% of Gr-1hi SSChi cells in the bone marrow were derived from CXCR2−/− cells; P < 0.01). Neutrophil trafficking from the bone marrow was estimated by calculating the percentage of neutrophils in the blood out of the total amount in the blood and bone marrow (neutrophil distribution index or NDI). We estimated that 1.3 ± 0.2% of wild-type neutrophils were in the blood, but the percentage of CXCR2−/− neutrophils in the blood was reduced to 0.4 ± 0.1% (P < 0.01). These data provide genetic evidence that CXCR2 signals promote neutrophil release from the bone marrow in a cell-autonomous manner. To explore the epistatic relationship of CXCR2 and CXCR4 signals to neutrophil trafficking, the neutrophil response to AMD3100, a small molecule CXCR4 antagonist, was examined in the CXCR2−/− mixed chimeras. Consistent with previous reports, treatment with AMD3100 resulted in a 5.2 ± 0.7-fold increase in wild-type neutrophils in the blood one hour after administration. In contrast, AMD3100 induced release of CXCR2−/− neutrophils was impaired, with only a 2.8 ± 0.3-fold increase observed (P < 0.05). G-CSF treatment is thought to induce neutrophil release through disruption of CXCR4 signaling. Thus, we next characterized the neutrophil response to 5 days of G-CSF treatment. Wild-type neutrophils displayed a shift from the bone marrow to the blood, with an NDI of 5.0 ± 0.4%. The number of CXCR2−/−neutrophils in the blood increased after treatment, but the percentage in the blood (2.5 ± 0.7%) was less than wild-type (P < 0.05). These data show that maximal neutrophil release requires the coordinated regulation of CXCR2 and CXCR4 signals. Studies are underway to assess neutrophil trafficking of CXCR4−/− × CXCR2−/− neutrophils. The tug-of-war model of neutrophil trafficking in the bone marrow predicts that CXCR2 ligands will be highly expressed in bone marrow endothelial cells or other cells closely associated with the endothelium. To test this prediction, endothelial cells (CD45− Ter119− CD31+) were sorted from the bone marrow of wild-type mice at baseline or after 5 days of G-CSF treatment. RNA expression profiling showed constitutive high level expression of the CXCR2 ligands CXCL1 and CXCL2. Moreover, expression of CXCL2 was significantly induced after G-CSF treatment. Chemokine expression was confirmed by real time RT-PCR and ELISA. Taken together, our data suggest that CXCR2 signaling is a second chemokine pathway that, in coordination with CXCR4, controls neutrophil release from the bone marrow. Disclosures: No relevant conflicts of interest to declare.

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Antas, Paulo, Steven Holland et Timothy Sterling. « Abnormal spontaneous interleukin 8 receptor expression : a brief report of two cases ». Revista da Sociedade Brasileira de Medicina Tropical 45, n^o 1 (février 2012) : 134–37. http://dx.doi.org/10.1590/s0037-86822012000100029.

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Interleukin 8 (CXCL8) is an autocrine chemokine specific for the chemoattraction and activation of granulocytes, NKT cells and T lymphocytes. Patients with tuberculosis and latent Mycobacterium tuberculosis infection were assessed for the spontaneous expression of CXCR1 (CD128) and CXCR2 on lymphocytes and monocytes. Compared with ex vivo profiles, increased spontaneous CXCR2 expression and normal CXCR1 expression were found on lymphocytes in two out of 59 individuals. Monocytes showed normal ex vivo profiles for both receptors. After stimulation with purified protein derivative, the in vitro levels of CXCL8 were below the median levels of all patients with prior tuberculosis. Spontaneous CXCR2 modulation did not cause notable variation in the in vitro levels of CXCL8.

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Cummings, C. James, Thomas R. Martin, Charles W. Frevert, Joanne M. Quan, Venus A. Wong, Steven M. Mongovin, Tonja R. Hagen, Kenneth P. Steinberg et Richard B. Goodman. « Expression and Function of the Chemokine Receptors CXCR1 and CXCR2 in Sepsis ». Journal of Immunology 162, n^o 4 (15 février 1999) : 2341–46. http://dx.doi.org/10.4049/jimmunol.162.4.2341.

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Abstract Neutrophils (polymorphonuclear neutrophils; PMN) and a redundant system of chemotactic cytokines (chemokines) have been implicated in the pathogenesis of the acute respiratory distress syndrome in patients with sepsis. PMN express two cell surface receptors for the CXC chemokines, CXCR1 and CXCR2. We investigated the expression and function of these receptors in patients with severe sepsis. Compared with normal donors, CXCR2 surface expression was down-regulated by 50% on PMN from septic patients (p < 0.005), while CXCR1 expression persisted. In vitro migratory responses to the CXCR1 ligand, IL-8, were similar in PMN from septic patients and normal donors. By contrast, the migratory response to the CXCR2 ligands, epithelial cell-derived neutrophil activator (ENA-78) and the growth-related oncogene proteins, was markedly suppressed in PMN from septic patients (p < 0.05). Ab specific for CXCR1 blocked in vitro migration of PMN from septic patients to IL-8 (p < 0.05), but not to FMLP. Thus, functionally significant down-regulation of CXCR2 occurs on PMN in septic patients. We conclude that in a complex milieu of multiple CXC chemokines, CXCR1 functions as the single dominant CXC chemokine receptor in patients with sepsis. These observations offer a potential strategy for attenuating adverse inflammation in sepsis while preserving host defenses mediated by bacteria-derived peptides such as FMLP.

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Clemetson, Kenneth J., Jeannine M. Clemetson, Amanda E. I. Proudfoot, Christine A. Power, Marco Baggiolini et Timothy N. C. Wells. « Functional expression of CCR1, CCR3, CCR4, and CXCR4 chemokine receptors on human platelets ». Blood 96, n^o 13 (15 décembre 2000) : 4046–54. http://dx.doi.org/10.1182/blood.v96.13.4046.

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Abstract Platelets are known to contain platelet factor 4 and β-thromboglobulin, α-chemokines containing the CXC motif, but recent studies extended the range to the β-family characterized by the CC motif, including RANTES and Gro-α. There is also evidence for expression of chemokine receptors CCR4 and CXCR4 in platelets. This study shows that platelets have functional CCR1, CCR3, CCR4, and CXCR4 chemokine receptors. Polymerase chain reaction detected chemokine receptor messenger RNA in platelet RNA. CCR1, CCR3, and especially CCR4 gave strong signals; CXCR1 and CXCR4 were weakly positive. Flow cytometry with specific antibodies showed the presence of a clear signal for CXCR4 and weak signals for CCR1 and CCR3, whereas CXCR1, CXCR2, CXCR3, and CCR5 were all negative. Immunoprecipitation and Western blotting with polyclonal antibodies to cytoplasmic peptides clearly showed the presence of CCR1 and CCR4 in platelets in amounts comparable to monocytes and CCR4 transfected cells, respectively. Chemokines specific for these receptors, including monocyte chemotactic protein 1, macrophage inflammatory peptide 1α, eotaxin, RANTES, TARC, macrophage-derived chemokine, and stromal cell–derived factor 1, activate platelets to give Ca++ signals, aggregation, and release of granule contents. Platelet aggregation was dependent on release of adenosine diphosphate (ADP) and its interaction with platelet ADP receptors. Part, but not all, of the Ca++ signal was due to ADP release feeding back to its receptors. Platelet activation also involved heparan or chondroitin sulfate associated with the platelet surface and was inhibited by cleavage of these glycosaminoglycans or by heparin or low molecular weight heparin. These platelet receptors may be involved in inflammatory or allergic responses or in platelet activation in human immunodeficiency virus infection.

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Clemetson, Kenneth J., Jeannine M. Clemetson, Amanda E. I. Proudfoot, Christine A. Power, Marco Baggiolini et Timothy N. C. Wells. « Functional expression of CCR1, CCR3, CCR4, and CXCR4 chemokine receptors on human platelets ». Blood 96, n^o 13 (15 décembre 2000) : 4046–54. http://dx.doi.org/10.1182/blood.v96.13.4046.h8004046_4046_4054.

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Platelets are known to contain platelet factor 4 and β-thromboglobulin, α-chemokines containing the CXC motif, but recent studies extended the range to the β-family characterized by the CC motif, including RANTES and Gro-α. There is also evidence for expression of chemokine receptors CCR4 and CXCR4 in platelets. This study shows that platelets have functional CCR1, CCR3, CCR4, and CXCR4 chemokine receptors. Polymerase chain reaction detected chemokine receptor messenger RNA in platelet RNA. CCR1, CCR3, and especially CCR4 gave strong signals; CXCR1 and CXCR4 were weakly positive. Flow cytometry with specific antibodies showed the presence of a clear signal for CXCR4 and weak signals for CCR1 and CCR3, whereas CXCR1, CXCR2, CXCR3, and CCR5 were all negative. Immunoprecipitation and Western blotting with polyclonal antibodies to cytoplasmic peptides clearly showed the presence of CCR1 and CCR4 in platelets in amounts comparable to monocytes and CCR4 transfected cells, respectively. Chemokines specific for these receptors, including monocyte chemotactic protein 1, macrophage inflammatory peptide 1α, eotaxin, RANTES, TARC, macrophage-derived chemokine, and stromal cell–derived factor 1, activate platelets to give Ca++ signals, aggregation, and release of granule contents. Platelet aggregation was dependent on release of adenosine diphosphate (ADP) and its interaction with platelet ADP receptors. Part, but not all, of the Ca++ signal was due to ADP release feeding back to its receptors. Platelet activation also involved heparan or chondroitin sulfate associated with the platelet surface and was inhibited by cleavage of these glycosaminoglycans or by heparin or low molecular weight heparin. These platelet receptors may be involved in inflammatory or allergic responses or in platelet activation in human immunodeficiency virus infection.

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Ye, Shaojing, Fei Ma, Dlovan F. D. Mahmood, Katherine L. Meyer-Siegler, Raymond E. Menard, David E. Hunt, Lin Leng, Richard Bucala et Pedro L. Vera. « Intravesical CD74 and CXCR4, macrophage migration inhibitory factor (MIF) receptors, mediate bladder pain ». PLOS ONE 16, n^o 8 (23 août 2021) : e0255975. http://dx.doi.org/10.1371/journal.pone.0255975.

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Background Activation of intravesical protease activated receptor 4 (PAR4) leads to release of urothelial macrophage migration inhibitory factor (MIF). MIF then binds to urothelial MIF receptors to release urothelial high mobility group box-1 (HMGB1) and elicit bladder hyperalgesia. Since MIF binds to multiple receptors, we investigated the contribution of individual urothelial MIF receptors to PAR4-induced HMGB1 release in vivo and in vitro and bladder pain in vivo. Methodology/Principal findings We tested the effect of intravesical pre-treatment with individual MIF or MIF receptor (CD74, CXCR4, CXCR2) antagonists on PAR4-induced HMGB1 release in vivo (female C57/BL6 mice) and in vitro (primary human urothelial cells) and on PAR4-induced bladder hyperalgesia in vivo (mice). In mice, PAR4 induced HMGB1 release and bladder hyperalgesia through activation of intravesical MIF receptors, CD74 and CXCR4. CXCR2 was not involved in these effects. In primary urothelial cells, PAR4-induced HMGB1 release through activation of CD74 receptors. Micturition parameters in mice were not changed by any of the treatments. Conclusions/Significance Urothelial MIF receptors CD74 and CXCR4 mediate bladder pain through release of urothelial HMGB1. This mechanism may set up persistent pain loops in the bladder and warrants further investigation. Urothelial CD74 and CXCR4 may provide novel targets for interrupting bladder pain.

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Semple, Bridgette D., Thomas Kossmann et Maria Cristina Morganti-Kossmann. « Role of Chemokines in CNS Health and Pathology : A Focus on the CCL2/CCR2 and CXCL8/CXCR2 Networks ». Journal of Cerebral Blood Flow & ; Metabolism 30, n^o 3 (11 novembre 2009) : 459–73. http://dx.doi.org/10.1038/jcbfm.2009.240.

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Chemokines and their receptors have crucial roles in the trafficking of leukocytes, and are of particular interest in the context of the unique immune responses elicited in the central nervous system (CNS). The chemokine system CC ligand 2 (CCL2) with its receptor CC receptor 2 (CCR2), as well as the receptor CXCR2 and its multiple ligands CXCL1, CXCL2 and CXCL8, have been implicated in a wide range of neuropathologies, including trauma, ischemic injury and multiple sclerosis. This review aims to overview the current understanding of chemokines as mediators of leukocyte migration into the CNS under neuroinflammatory conditions. We will specifically focus on the involvement of two chemokine networks, namely CCL2/CCR2 and CXCL8/CXCR2, in promoting macrophage and neutrophil infiltration, respectively, into the lesioned parenchyma after focal traumatic brain injury. The constitutive brain expression of these chemokines and their receptors, including their recently identified roles in the modulation of neuroprotection, neurogenesis, and neurotransmission, will be discussed. In conclusion, the value of evidence obtained from the use of Ccl2- and Cxcr2-deficient mice will be reported, in the context of potential therapeutics inhibiting chemokine activity which are currently in clinical trial for various inflammatory diseases.

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Tecimer, Tülay, Jeffrey Dlott, Anan Chuntharapai, Alvin W. Martin et Stephen C. Peiper. « Expression of the Chemokine Receptor CXCR2 in Normal and Neoplastic Neuroendocrine Cells ». Archives of Pathology & ; Laboratory Medicine 124, n^o 4 (1 avril 2000) : 520–25. http://dx.doi.org/10.5858/2000-124-0520-eotcrc.

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Abstract Background.—Chemokines effect their proinflammatory and growth regulatory roles through interaction with serpentine receptors. One such receptor, CXCR2, binds multiple CXC chemokines, including interleukin 8, GRO-α, GRO-β, GRO-γ, and NAP-2. We have previously identified CXCR2 expression on myeloid cells, notably mature granulocytes, and projection neurons. Objective.—To determine the expression of CXCR2 by cells of the neuroendocrine system. Design.—Archival specimens from normal neuroendocrine tissues and their malignant counterparts were analyzed by immunohistochemistry with monoclonal antibodies specific for CXCR1 and CXCR2. Results.—Immunohistochemical analysis revealed high-level expression of CXCR2 by cells in the pituitary, adrenal medulla, pancreatic islets, thyroid C cells, scattered Kulchitsky cells in the bronchi, and counterpart neuroendocrine cells in the stomach, small bowel, colon, and appendix. Neuroendocrine neoplasms that demonstrated high-level CXCR2 expression included (1) primary carcinoids localized to the stomach, small bowel, colon, appendix, fallopian tube, ovary, and lung; (2) atypical carcinoids of the lung; (3) metastatic carcinoids; (4) pituitary adenomas; (5) pheochromocytomas; and (6) medullary carcinomas of the thyroid. Small cell lung carcinomas, large cell neuroendocrine carcinomas of the lung, small cell carcinoma of the cervix, Merkel cell carcinomas, neuroblastomas, and malignant melanomas lacked evidence of CXCR2 expression. Conclusions.—The expression of CXCR2 by normal neuroendocrine cells and neoplastic counterparts that have retained phenotypic features of this differentiation program suggests that chemokines may play an important role in functions that are characteristic of this cell type. In addition, this raises the possibility that chemokines may modulate secretion of biologically active products of these cells and their neoplastic counterparts.

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Takahashi, Masafumi, Takatoshi Ishiko, Hidenobu Kamohara, Hideaki Hidaka, Osamu Ikeda, Michio Ogawa et Hideo Baba. « Curcumin (1,7-bis(4-hydroxy-3-methoxyphenyl)-1, 6-heptadiene-3,5-dione) Blocks the Chemotaxis of Neutrophils by Inhibiting Signal Transduction through IL-8 Receptors ». Mediators of Inflammation 2007 (2007) : 1–11. http://dx.doi.org/10.1155/2007/10767.

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We investigated the impact of curcumin on neutrophils. Chemotactic activity via human recombinant IL-8 (hrIL-8) was significantly inhibited by curcumin. Curcumin reduced calcium ion flow induced by internalization of the IL-8 receptor. We analyzed flow cytometry to evaluate the status of the IL-8 receptor after curcumin treatment. The change in the distribution of receptors intracellularly and on the cell surface suggested that curcumin may affect the receptor trafficking pathway intracellulary. Rab11 is a low molecular weight G protein associated with the CXCR recycling pathway. Following curcumin treatment, immunoprecipitation studies showed that the IL-8 receptor was associated with larger amounts of active Rab11 than that in control cells. These data suggest that curcumin induces the stacking of the Rab11 vesicle complex with CXCR1 and CXCR2 in the endocytic pathway. The mechanism for antiinflammatory response by curcumin may involve unique regulation of the Rab11 trafficking molecule in recycling of IL-8 receptors.

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Sobolik, Tammy, Ying-jun Su, Sam Wells, Gregory D. Ayers, Rebecca S. Cook et Ann Richmond. « CXCR4 drives the metastatic phenotype in breast cancer through induction of CXCR2 and activation of MEK and PI3K pathways ». Molecular Biology of the Cell 25, n^o 5 (mars 2014) : 566–82. http://dx.doi.org/10.1091/mbc.e13-07-0360.

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Aberrant expression of CXCR4 in human breast cancer correlates with metastasis to tissues secreting CXCL12. To understand the mechanism by which CXCR4 mediates breast cancer metastasis, MCF-7 breast carcinoma cells were transduced to express wild-type CXCR4 (CXCR4WT) or constitutively active CXCR4 (CXCR4ΔCTD) and analyzed in two-dimensional (2D) cultures, three-dimensional reconstituted basement membrane (3D rBM) cultures, and mice using intravital imaging. Two-dimensional cultures of MCF-7 CXCR4ΔCTD cells, but not CXCR4WT, exhibited an epithelial-to-mesenchymal transition (EMT) characterized by up-regulation of zinc finger E box–binding homeobox 1, loss of E-cadherin, up-regulation of cadherin 11, p120 isoform switching, activation of extracellular signal-regulated kinase 1/2, and matrix metalloproteinase-2. In contrast to the 2D environment, MCF-7 CXCR4WT cells cultured in 3D rBM exhibited an EMT phenotype, accompanied by expression of CXCR2, CXCR7, CXCL1, CXCL8, CCL2, interleukin-6, and granulocyte–macrophage colony stimulating factor. Dual inhibition of CXCR2 with CXCR4, or inhibition of either receptor with inhibitors of mitogen-activated protein kinase 1 or phosphatidylinositol 3-kinase, reversed the aggressive phenotype of MCF-7 CXCR4-expressing or MDA-MB-231 cells in 3D rBM. Intravital imaging of CXCR4-expressing MCF-7 cells revealed that tumor cells migrate toward blood vessels and metastasize to lymph nodes. Thus CXCR4 can drive EMT along with an up-regulation of chemokine receptors and cytokines important in cell migration, lymphatic invasion, and tumor metastasis.

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Sharma, Bhawna, Seema Singh, Michelle L. Varney et Rakesh K. Singh. « Targeting CXCR1/CXCR2 receptor antagonism in malignant melanoma ». Expert Opinion on Therapeutic Targets 14, n^o 4 (15 mars 2010) : 435–42. http://dx.doi.org/10.1517/14728221003652471.

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Fan, Guo-Huang, Lynne A. Lapierre, James R. Goldenring et Ann Richmond. « Differential regulation of CXCR2 trafficking by Rab GTPases ». Blood 101, n^o 6 (15 mars 2003) : 2115–24. http://dx.doi.org/10.1182/blood-2002-07-1965.

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Intracellular trafficking of chemokine receptors plays an important role in fine-tuning the functional responses of neutrophils and lymphocytes in the inflammatory process and HIV infection. Although many chemokine receptors internalize through clathrin-coated pits, regulation of the receptor trafficking is not fully understood. The present study demonstrated that CXCR2 was colocalized with transferrin and low-density lipoprotein (LDL) after agonist treatment for different periods of time, suggesting 2 intracellular trafficking pathways for this receptor. CXCR2 was colocalized with Rab5 and Rab11a, which are localized in early and recycling endosomes, respectively, in response to agonist stimulation for a short period of time, suggesting a recycling pathway for the receptor trafficking. However, overexpression of a dominant-negative Rab5-S34N mutant significantly attenuated CXCR2 sequestration. The internalized CXCR2 was recycled back to the cell surface after removal of the agonist and recovery of the cells, but receptor recycling was inhibited by overexpression of a dominant-negative Rab11a-S25N mutant. After prolonged (4-hour) agonist treatment, CXCR2 exhibited significantly increased colocalization with Rab7, which is localized in late endosomes. The colocalization of CXCR2 with LDL and LAMP-1 suggests that CXCR2 is targeted to lysosomes for degradation after prolonged ligand treatment. However, the colocalization of CXCR2 with Lamp1 was blocked by the overexpression of a dominant-negative Rab7-T22N mutant. In cells overexpressing Rab7-T22N, CXCR2 was retained in the Rab5- and Rab11a-positive endosomes after prolonged (4-hour) agonist treatment. Our data suggest that the intracellular trafficking of CXCR2 is differentially regulated by Rab proteins.

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Joseph, Prem Raj B., Kirti V. Sawant et Krishna Rajarathnam. « Heparin-bound chemokine CXCL8 monomer and dimer are impaired for CXCR1 and CXCR2 activation : implications for gradients and neutrophil trafficking ». Open Biology 7, n^o 11 (novembre 2017) : 170168. http://dx.doi.org/10.1098/rsob.170168.

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Chemokine CXCL8 plays a pivotal role in host immune response by recruiting neutrophils to the infection site. CXCL8 exists as monomers and dimers, and mediates recruitment by interacting with glycosaminoglycans (GAGs) and activating CXCR1 and CXCR2 receptors. How CXCL8 monomer and dimer interactions with both receptors and GAGs mediate trafficking is poorly understood. In particular, both haptotactic (mediated by GAG-bound chemokine) and chemotactic (mediated by soluble chemokine) gradients have been implicated, and whether it is the free or the GAG-bound CXCL8 monomer and/or dimer that activates the receptor remains unknown. Using solution NMR spectroscopy, we have now characterized the binding of heparin-bound CXCL8 monomer and dimer to CXCR1 and CXCR2 receptor N-domains. Our data provide compelling evidence that heparin-bound monomers and dimers are unable to bind either of the receptors. Cellular assays also indicate that heparin-bound CXCL8 is impaired for receptor activity. Considering dimer binds GAGs with higher affinity, dimers will exist predominantly in the GAG-bound form and the monomer in the free form. We conclude that GAG interactions determine the levels of free CXCL8, and that it is the free, and not GAG-bound, CXCL8 that activates the receptors and mediates recruitment of blood neutrophils to the infected tissue.

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Desbaillets, Isabelle, Annie-Claire Diserens, Nicolas de Tribolet, Marie-France Hamou et Erwin G. Van Meir. « Upregulation of Interleukin 8 by Oxygen-deprived Cells in Glioblastoma Suggests a Role in Leukocyte Activation, Chemotaxis, and Angiogenesis ». Journal of Experimental Medicine 186, n^o 8 (20 octobre 1997) : 1201–12. http://dx.doi.org/10.1084/jem.186.8.1201.

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Leukocyte infiltration and necrosis are two biological phenomena associated with the development of neovascularization during the malignant progression of human astrocytoma. Here, we demonstrate expression of interleukin (IL)-8, a cytokine with chemotactic and angiogenic properties, and of IL-8–binding receptors in astrocytoma. IL-8 expression is first observed in low grade astrocytoma in perivascular tumor areas expressing inflammatory cytokines. In glioblastoma, it further localizes to oxygen-deprived cells surrounding necrosis. Hypoxic/anoxic insults on glioblastoma cells in vitro using anaerobic chamber systems or within spheroids developing central necrosis induced an increase in IL-8 messenger RNA (mRNA) and protein expression. mRNA for IL-8–binding chemokine receptors CXCR1, CXCR2, and the Duffy antigen receptor for chemokines (DARC) were found in all astrocytoma grades by reverse transcription/PCR analysis. In situ hybridization and immunohistochemistry localized DARC expression on normal brain and tumor microvascular cells and CXCR1 and CXCR2 expression to infiltrating leukocytes. These results support a model where IL-8 expression is initiated early in astrocytoma development through induction by inflammatory stimuli and later in tumor progression increases due to reduced microenvironmental oxygen pressure. Augmented IL-8 would directly and/or indirectly promote angiogenesis by binding to DARC and by inducing leukocyte infiltration and activation by binding to CXCR1 and CXCR2.

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Mizutani, Tatsushi. « A Reciprocal Cross-Reactivity between Monoclonal Antibodies to SARS-CoV-2 Spike Glycoprotein S1 and Human CXCR2—An Implication of a Viral Mimic of Human CXCR2 ». COVID 2, n^o 5 (2 mai 2022) : 569–77. http://dx.doi.org/10.3390/covid2050042.

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Some viruses contain mimics of host chemokine receptors that influence host immunity; however, such viral mimics have not yet been reported for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this study, I focused on C-X-C motif chemokine receptor 2 (CXCR2) as a candidate chemokine receptor exploited by SARS-CoV-2. Similarities between the extracellular domain (ECD) of human CXCR2 and the SARS-CoV-2 spike glycoprotein S1 (CoV2S1) were investigated. Flow cytometric analysis of healthy donor-derived peripheral leukocytes was performed to examine the cross-reactivity between specific monoclonal antibodies against these two proteins. The results showed that CR3022, a monoclonal antibody to the receptor binding domain of CoV2S1, recognized the CXCR2 ECD, and a murine monoclonal antibody to human CXCR2 recognized recombinant CoV2S1. This reciprocal cross-reactivity suggests that CoV2S1 harbors a mimic of the CXCR2 ECD.

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Cardona, Astrid E., Margaret E. Sasse, Liping Liu, Sandra M. Cardona, Makiko Mizutani, Carine Savarin, Taofang Hu et Richard M. Ransohoff. « Scavenging roles of chemokine receptors : chemokine receptor deficiency is associated with increased levels of ligand in circulation and tissues ». Blood 112, n^o 2 (15 juillet 2008) : 256–63. http://dx.doi.org/10.1182/blood-2007-10-118497.

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Abstract In vitro studies have implicated chemokine receptors in consumption and clearance of specific ligands. We studied the role that various signaling chemokine receptors play during ligand homeostasis in vivo. We examined the levels of ligands in serum and CNS tissue in mice lacking chemokine receptors. Compared with receptor-sufficient controls, Cx3cr1−/− mice exhibited augmented levels of CX3CL1 both in serum and brain, and circulating levels of CXCL1 and CXCL2 were increased in Cxcr2−/− mice. CCR2-deficient mice showed significantly increased amounts of circulating CCL2 compared with wild-type mice. Cxcr3−/− mice revealed increased levels of circulating and brain CXCL10 after experimental autoimmune encephalomyelitis (EAE) induction. CCR2-deficient peripheral blood and resident peritoneal cells exhibited reduced binding capacity and biologic responses to the CCR1 ligand CCL3, suggesting that elevated levels of CCR2 ligands had down-regulated CCR1. The results indicate that signaling chemokine receptors clear chemokines from circulation and tissues. These homeostatic functions of signaling chemokine receptors need to be integrated into safety and efficacy calculations when considering therapeutic receptor blockade.

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Skuhersky, Michael A., Fei Tao, Rui Qing, Eva Smorodina, David Jin et Shuguang Zhang. « Comparing Native Crystal Structures and AlphaFold2 Predicted Water-Soluble G Protein-Coupled Receptor QTY Variants ». Life 11, n^o 12 (24 novembre 2021) : 1285. http://dx.doi.org/10.3390/life11121285.

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Accurate predictions of 3-dimensional protein structures by AlphaFold2 is a game-changer for biology, especially for structural biology. Here we present the studies of several native chemokine receptors including CCR5, CCR9, CXCR2 and CXCR4 determined by X-ray crystallography, and their water-soluble QTY counter parts predicted by AlphaFold2. In the native structures, there are hydrophobic amino acids leucine (L), isoleucine (I), valine (V) and phenylalanine (F) in the transmembrane helices. These hydrophobic amino acids are systematically replaced by hydrophilic amino acids glutamine (Q), threonine (T), and tyrosine (Y). Thus, the QTY variants become water-soluble. We also present the superimposed structures of native CCR10, CXCR5, CXCR7 and an olfactory receptor OR1D2 and their water-soluble QTY variants. Since the CryoEM structural determinations for the QTY variants of CCR10QTY and OR1D2QTY are in progress, it will be of interest to compare them when the structures become available. The superimposed structures show remarkable similarity within RMSD 1Å–2Å despite significant sequence differences (~26%–~33%). We also show the differences of hydrophobicity patches between the native GPCR and their QTY variants. Our study provides insight into the subtle differences between the hydrophobic helices and hydrophilic helices, and may further stimulate designs of water-soluble membrane proteins and other aggregated proteins.

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Konishi, Takanori, Rebecca M. Schuster, Holly S. Goetzman, Charles C. Caldwell et Alex B. Lentsch. « Cell-specific regulatory effects of CXCR2 on cholestatic liver injury ». American Journal of Physiology-Gastrointestinal and Liver Physiology 317, n^o 6 (1 décembre 2019) : G773—G783. http://dx.doi.org/10.1152/ajpgi.00080.2019.

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The CXC chemokine receptor 2 (CXCR2) is critical for neutrophil recruitment and hepatocellular viability but has not been studied in the context of cholestatic liver injury following bile duct ligation (BDL). The present study sought to elucidate the cell-specific roles of CXCR2 on acute liver injury after BDL. Wild-type and CXCR2−/− mice were subjected BDL. CXCR2 chimeric mice were created to assess the cell-specific role of CXCR2 on liver injury after BDL. SB225002, a selective CXCR2 antagonist, was administrated intraperitoneally after BDL to investigate the potential of pharmacological inhibition. CXCR2−/− mice had significantly less liver injury than wild-type mice at 3 and 14 days after BDL. There was no difference in biliary fibrosis among groups. The chemokines CXCL1 and CXCL2 were induced around areas of necrosis and biliary structures, respectively, both areas where neutrophils accumulated after BDL. CXCR2−/− mice showed significantly less neutrophil accumulation in those injured areas. CXCR2Liver+/Myeloid+ and CXCR2Liver−/Myeloid− mice recapitulated the wild-type and CXCR2-knockout phenotypes, respectively. CXCR2Liver+/Myeloid+ mice suffered higher liver injury than CXCR2Liver+/Myeloid− and CXCR2Liver−/Myeloid+; however, only those chimeras with knockout of myeloid CXCR2 (CXCR2Liver+/Myeloid− and CXCR2Liver−/Myeloid−) showed reduction of neutrophil accumulation around areas of necrosis. Daily administration of SB225002 starting after 3 days of BDL reduced established liver injury at 6 days. In conclusion, neutrophil CXCR2 guides the cell to the site of injury, while CXCR2 on liver cells affects liver damage independent of neutrophil accumulation. CXCR2 appears to be a viable therapeutic target for cholestatic liver injury. NEW & NOTEWORTHY This study is the first to reveal cell-specific roles of the chemokine receptor CXCR2 in cholestatic liver injury caused by bile duct ligation. CXCR2 on neutrophils facilitates neutrophil recruitment to the liver, while CXCR2 on liver cells contributes to liver damage independent of neutrophils. CXCR2 may represent a viable therapeutic target for cholestatic liver injury.

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Ranganathan, Punithavathi, Calpurnia Jayakumar, Santhakumar Manicassamy et Ganesan Ramesh. « CXCR2 knockout mice are protected against DSS-colitis-induced acute kidney injury and inflammation ». American Journal of Physiology-Renal Physiology 305, n^o 10 (15 novembre 2013) : F1422—F1427. http://dx.doi.org/10.1152/ajprenal.00319.2013.

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Organ cross talk exists in many diseases of the human and animal models of human diseases. A recent study demonstrated that inflammatory mediators can cause acute kidney injury and neutrophil infiltration in a mouse model of dextran sodium sulfate (DSS)-colitis. However, the chemokines and their receptors that may mediate distant organ effects in colitis are unknown. We hypothesized that keratinocyte chemoattractant (KC)/IL-8 receptor chemokine (C-X-C motif) ligand 2 (CXCL2) mediates DSS-colitis-induced acute kidney injury. Consistent with our hypothesis, wild-type (WT) mice developed severe colitis with DSS treatment, which was associated with inflammatory cytokine and chemokine expression and neutrophil infiltration in the colon. DSS-colitis in WT was accompanied by acute kidney injury and enhanced expression of inflammatory cytokines in the kidney. However, CXCR2 knockout mice were protected against DSS-colitis as well as acute kidney injury. Moreover, the expression of cytokines and chemokines and neutrophil infiltration was blunted in CXCR2 knockout mice in the colon and kidney. Administration of recombinant KC exacerbated DSS-colitis-induced acute kidney injury. Our results suggest that KC/IL-8 and its receptor CXCR2 are critical and major mediators of organ cross talk in DSS colitis and neutralization of CXCR2 will help to reduce the incidence of acute kidney injury due to ulcerative colitis and Crohn's disease in humans.

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Cho, Hee Seong, Young In Choi, Seon Uk Park, Yi Seul Han, Jean Kwon et Sung Jun Jung. « Prevention of Chemotherapy-Induced Peripheral Neuropathy by Inhibiting C-X-C Motif Chemokine Receptor 2 ». International Journal of Molecular Sciences 24, n^o 3 (17 janvier 2023) : 1855. http://dx.doi.org/10.3390/ijms24031855.

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Chemotherapy-induced peripheral neuropathy (CIPN) is a major drawback in the use of chemotherapeutic agents for patients with cancer. Although studies have investigated a broad number of molecules that might be related to CIPN, the differences in the chemokine pathways between various chemotherapeutic agents, such as vincristine and oxaliplatin, which are some of the most widely used treatments, have not been fully elucidated. We confirmed that the administration (intraperitoneal injections for seven days) of vincristine (0.1 mg/kg) and oxaliplatin (3 mg/kg) induced pain by using the von Frey behavioral test. Subsequent applications with vincristine and oxaliplatin led to mechanical allodynia that lasted more than one week from the fifth day. After the induction of mechanical allodynia, the mRNA expression of CXCR2, CXCL1, CXCL3, and CXCL5 was examined in the dorsal root ganglia (DRG) and spinal cord of the CIPN models. As a result, the mRNA expression of CXCR2 robustly increased in the lumbar spinal cord in the oxaliplatin-treated mice. Next, to evaluate the involvement of CXCR2 in CIPN, reparixin, a CXCR1/2 inhibitor, was administered intrathecally or intraperitoneally with vincristine or oxaliplatin and was further verified by treatment with ruxolitinib, which inhibits Janus kinase 2 downstream of the CXCR1/2 pathway. Reparixin and ruxolitinib blocked oxaliplatin-induced allodynia but not vincristine-induced allodynia, which suggests that CXCR2-related pathways are associated with the development of oxaliplatin-induced neuropathy. Together with the above results, this suggests that the prevention of oxaliplatin-induced neuropathy by CXCR2 inhibition can lead to successful chemotherapy, and it is important to provide appropriate countermeasures against CIPN development for each specific chemotherapeutic agent.

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Murashka, D. I., A. D. Tahanovich, M. M. Kauhanka, O. V. Gotko et V. I. Prokhorova. « On the issue of diagnostic value of determining the level of receptors and their ligands in blood in non-small cell lung cancer ». Russian Clinical Laboratory Diagnostics 67, n^o 5 (21 mai 2022) : 277–85. http://dx.doi.org/10.51620/0869-2084-2022-67-5-277-285.

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Non-small cell lung cancer (NSCLC) occupies the first place in the structure of mortality due to oncological diseases. Late diagnosis worsens the effectiveness of its treatment. There are no informative biomarkers that allow us to judge the prevalence of the tumor process, especially in the early stages of NSCLC. To determine the level of CXCL5, CXCL8, CXCR1 and CXCR2 in the peripheral blood of patients with NSCLC to assess the possibility of their use in the diagnosis of the disease. The material was the blood of 218 patients with NSCLC, 19 patients with lung hamartoma and 42 healthy people. The concentration of CXCL5, CXCL8, and SCC in blood serum was determined by enzyme immunoassay, the CYFRA 21-1 level was determined by immunochemiluminescence analysis. The proportion of leukocytes equipped with CXCR1 and CXCR2 receptors and the fluorescence intensity of receptor complexes with antibodies (MFI) in them were measured by flow cytometry. MFI CXCR1 in granulocytes and the proportion of lymphocytes supplied CXCR2, increased in the blood already at stage I of NSCLC and showed an even more significant increase in subsequent stages. The level of these indicators was correlatively related to the stages and characteristics of NSCLC. Measuring the level of MFI CXCR1 in the blood serum makes it possible to diagnose the early stages of NSCLC with a sensitivity of 87.4% (specificity - 73.8%). Determination of the proportion of lymphocytes equipped with CXCR2 demonstrates comparable diagnostic sensitivity (87.2%) and specificity of 66.7% in the detection of stages I-II of NSCLC. MFI CXCR1 in granulocytes can also be used to differentiate stages I and II of NSCLC (diagnostic sensitivity - 75,3%, specificity - 69,6%). The sensitivity of determining for this purpose the proportion of lymphocytes equipped with CXCR2 is 75.0% with a specificity of 71.7%. In 89.7% of patients with stages III-IV NSCLC, the MFI CXCR1 in granulocytes exceeds the threshold value of 47.8 (specificity - 74.8%). Diagnostic sensitivity of determining the proportion of lymphocytes for this purpose was 90.7%.

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Nilsson, Gunnar, Judy A. Mikovits, Dean D. Metcalfe et Dennis D. Taub. « Mast Cell Migratory Response to Interleukin-8 Is Mediated Through Interaction With Chemokine Receptor CXCR2/Interleukin-8RB ». Blood 93, n^o 9 (1 mai 1999) : 2791–97. http://dx.doi.org/10.1182/blood.v93.9.2791.

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Abstract To explore the role of chemokines in mast cell chemotaxis and accumulation at sites of inflammation, we first investigated the response of human mast cells to 18 different chemokines by induction of intracellular calcium mobilization in the human mast cell line, HMC-1. Only a subgroup of CXC chemokines defined by the conserved sequence motif glutamic acid-leucine-arginine (ELR) tripeptide motif, which included interleukin-8 (IL-8), growth-regulated oncogene  (GRO), neutrophil-activating peptide-2 (NAP-2), and epithelial cell–derived neutrophil activating peptide-78 (ENA-78), induced calcium flux in the cells. These observations suggested that the receptor CXCR2 (IL-8RB) should be expressed on the surface of these cells. Using the RNAse protection assay, CXCR2 mRNA, but not CXCR1 (IL-8RA) mRNA expression was detected in HMC-1 cells. Flow cytometry analysis documented the surface expression of CXCR2. A binding analysis performed with125I-IL-8 determined that there were approximately 3,600 high affinity IL-8 binding sites per HMC-1 cell, with a calculated kd of 1.2 to 2 nmol/L. The activity of this receptor was further explored using IL-8, which was found to induce dose-dependent chemotactic and haptotactic responses in both HMC-1 cells and in vitro cultured human cord blood–derived mast cells. These results show the expression of functional CXCR2 receptors on the surface of human mast cells, which may play an important role in mast cell recruitment during the genesis of an inflammatory response.

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Nilsson, Gunnar, Judy A. Mikovits, Dean D. Metcalfe et Dennis D. Taub. « Mast Cell Migratory Response to Interleukin-8 Is Mediated Through Interaction With Chemokine Receptor CXCR2/Interleukin-8RB ». Blood 93, n^o 9 (1 mai 1999) : 2791–97. http://dx.doi.org/10.1182/blood.v93.9.2791.409k27_2791_2797.

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To explore the role of chemokines in mast cell chemotaxis and accumulation at sites of inflammation, we first investigated the response of human mast cells to 18 different chemokines by induction of intracellular calcium mobilization in the human mast cell line, HMC-1. Only a subgroup of CXC chemokines defined by the conserved sequence motif glutamic acid-leucine-arginine (ELR) tripeptide motif, which included interleukin-8 (IL-8), growth-regulated oncogene  (GRO), neutrophil-activating peptide-2 (NAP-2), and epithelial cell–derived neutrophil activating peptide-78 (ENA-78), induced calcium flux in the cells. These observations suggested that the receptor CXCR2 (IL-8RB) should be expressed on the surface of these cells. Using the RNAse protection assay, CXCR2 mRNA, but not CXCR1 (IL-8RA) mRNA expression was detected in HMC-1 cells. Flow cytometry analysis documented the surface expression of CXCR2. A binding analysis performed with125I-IL-8 determined that there were approximately 3,600 high affinity IL-8 binding sites per HMC-1 cell, with a calculated kd of 1.2 to 2 nmol/L. The activity of this receptor was further explored using IL-8, which was found to induce dose-dependent chemotactic and haptotactic responses in both HMC-1 cells and in vitro cultured human cord blood–derived mast cells. These results show the expression of functional CXCR2 receptors on the surface of human mast cells, which may play an important role in mast cell recruitment during the genesis of an inflammatory response.

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Holloman, Bryan L., Mitzi Nagarkatti et Prakash Nagarkatti. « Pulmonary macrophage activation and recruitment in lipopolysaccharide-induced acute lung injury mediates neutrophil infiltration : Role of AhR ligation in intervention ». Journal of Immunology 208, n^o 1_Supplement (1 mai 2022) : 105.36. http://dx.doi.org/10.4049/jimmunol.208.supp.105.36.

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Abstract CCL2-CCR2 signaling plays an essential role in the recruitment of macrophages and neutrophils following tissue injury. During inflammation, CCR2+ macrophage secretion of CCL2 induces an autocrine effect that leads to an intracellular signaling cascade of macrophages that promotes upregulation of CCL2, CXCL2, and CXCL3 expression, which stimulates the chemotaxis of blood circulating CCR2+ monocytes and CXCR2+ neutrophils to the disease site. Interestingly, the aryl hydrocarbon receptor (AhR) ligand has been shown to regulate effector cell recruitment. Therefore, we studied the effects of the AhR ligand, indole-3-carbinol (I3C) on the recruitment of circulating CCR2+ monocytes and CXCR2+ neutrophils during acute lung injury (ALI). To induce ALI in C57BL/6 mice and Ccr2gfp mice (mice deficient in the CCR2 receptor), they were given 5mg/kg of lipopolysaccharide intranasally. Mice were treated with I3C or vehicle following disease induction. Interestingly, I3C downregulated neutrophils expressing CXCR2 (a receptor associated with neutrophil recruitment) and CCR2+ macrophages in lungs of C57BL/6 diseased-mice. Furthermore, to determine if CCR2+ macrophages recruit CXCR2+ neutrophils, we induced ALI in Ccr2gfp mice. Abolishing the expression of CCR2 eliminated the recruitment of CXCR2+ neutrophils to the lungs during ALI. Interestingly, scRNASeq of macrophage/monocyte cells showed that I3C reduced expression of CXCL3. CXCL3 gene translates into the chemokine CXCL3, which binds to CXCR2 and is involved in neutrophil recruitment to the disease site. These findings suggest that CCR2 macrophages are involved in the recruitment of CXCR2+ neutrophils, and the AhR ligand I3C can regulate immune cell trafficking capabilities. Supported by NIH grants P01AT003961, P20GM103641, R01ES030144, R01AI129788, R01AI123947, R01AI160896 and R01AI123947-S2

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Salim, Juan P., Rosana F. Marta et Felisa C. Molinas. « Megakaryocyte-Active Chemokines : Dysregulation in the SDF-1a/CXCR4 Axis in Patients with Essential Thrombocythemia. » Blood 106, n^o 11 (16 novembre 2005) : 4969. http://dx.doi.org/10.1182/blood.v106.11.4969.4969.

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Abstract Chemokines belong to a large family of molecules that are implicated in the localization and production of blood cells. Some of them, such as Interleukin 8 (IL-8) and GRO-a, participate in the regulation of megakaryopoiesis, mostly by exerting an inhibitory action. Recently, the involvement of stromal derived factor 1 (SDF-1) in synergizing the stimulatory effect of thrombopoietin on megakaryopoiesis and its participation in megakaryocyte transendothelial migration has been described. The aim of the present study was the evaluation of the plasma levels of IL-8, GRO- a and SDF-1 in patients with essential thrombocythemia (ET), a myeloproliferative disorder characterized by megakaryocytic hyperproliferation with increased circulating platelet count. Besides, the corresponding chemokine receptors were assayed on platelet membrane from ET patients. A cohort of 27 patients diagnosed according to the Polycitemia Vera Study Group were enrolled in the study (mean age, 45; 21 women). Twenty-seven normal subjects matched by sex and age were taken as the control group. The Ethic Committee from IDIM A. Lanari approved the study and all patients and normal controls signed the informed consent. Plasma levels of the chemokines were measured by ELISA technique (R&D Systems) according to the manufacturer. Expression levels of IL-8 receptors (CXCR1 and CXCR2), GRO-a receptors (CXCR2) and SDF-1 receptors (CXCR4) on platelet membrane were evaluated by flow cytometry using specific MoAbs and the corresponding isotype controls (B-D Pharmingen). Flow cytometry results were expressed as relative fluorescence intensity (RFI, the relationship between the mean fluorescence intensity from the specific antibody and the isotype control). Results were expressed as median and range. Statistic analysis was carried out using Mann-Whitney Wilcoxon rank sum test and Wilcoxon signed rank test. Plasma levels of the chemokines measured in 19 ET patients were similar to that found in normal controls, IL-8 2.5, pg/ml (0.8–28.2) and 2.8 pg/ml (1.1–16.5), GRO-a, 30.0 pg/ml (7.4–463.1) and 23.9 pg/ml (9.6–148.0), SDF-1, 1895.0 pg/ml (1246.0–2719.0) and 1915.0 pg/ml (822–2424.0), respectively. The expression levels of CXCR4 receptor was found diminished in platelets from ET patients, RIF 16.94 (1.3–31.3) compared to normal controls, 27.4 (2.4–58.4); p=0.0059, n=10. However, the expression of CXCR1 and CXCR2 in platelets from ET patients was normal. In conclusion, although plasma levels of the chemoquines IL-8, GRO-a and SDF-1 were normal in these patients, the decreased level of CXCR4 on platelet membrane suggests a dysregulation in the SDF-1a/CXCR4 axis in patients with essential thrombocythemia.

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Korbecki, Jan, Patrycja Kupnicka, Mikołaj Chlubek, Jarosław Gorący, Izabela Gutowska et Irena Baranowska-Bosiacka. « CXCR2 Receptor : Regulation of Expression, Signal Transduction, and Involvement in Cancer ». International Journal of Molecular Sciences 23, n^o 4 (16 février 2022) : 2168. http://dx.doi.org/10.3390/ijms23042168.

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Chemokines are a group of about 50 chemotactic cytokines crucial for the migration of immune system cells and tumor cells, as well as for metastasis. One of the 20 chemokine receptors identified to date is CXCR2, a G-protein-coupled receptor (GPCR) whose most known ligands are CXCL8 (IL-8) and CXCL1 (GRO-α). In this article we present a comprehensive review of literature concerning the role of CXCR2 in cancer. We start with regulation of its expression at the transcriptional level and how this regulation involves microRNAs. We show the mechanism of CXCR2 signal transduction, in particular the action of heterotrimeric G proteins, phosphorylation, internalization, intracellular trafficking, sequestration, recycling, and degradation of CXCR2. We discuss in detail the mechanism of the effects of activated CXCR2 on the actin cytoskeleton. Finally, we describe the involvement of CXCR2 in cancer. We focused on the importance of CXCR2 in tumor processes such as proliferation, migration, and invasion of tumor cells as well as the effects of CXCR2 activation on angiogenesis, lymphangiogenesis, and cellular senescence. We also discuss the importance of CXCR2 in cell recruitment to the tumor niche including tumor-associated neutrophils (TAN), tumor-associated macrophages (TAM), myeloid-derived suppressor cells (MDSC), and regulatory T (Treg) cells.

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