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1: Inorganic chemistry, 2010 Jun 3,
The Trigonal Prismatic Cluster Compound W(6)CCl(15) and a Carambolage of Tungsten Clusters in the Structure of the Heteroleptic Cluster Compound W(30)C(2)(Cl,Br)(68).

[Abstract]Reactions between W(6)Cl(12) and carbon halides can initiate a cascade of reactions and reaction products, yielding W(6)Cl(18), W(6)CCl(18), and W(6)CCl(15) with increasing temperature, before decomposition into tungsten carbide is obtained. The new compound W(6)CCl(15) and the new heteroleptic compound W(30)C(2)(Cl,Br)(68) obtained from these reactions were structurally characterized. The structure of W(30)C(2)X(68) combines a carambolage of two distinct octahedral and one centered trigonal prismatic cluster in one structure as refined by X-ray single-crystal diffraction (P1, Z = 1; a = 12.003(2) A, b = 14.862(3) A, c = 15.792(3) A, alpha = 88.75(2) degrees , beta = 68.85(2) degrees , gamma = 71.19(2) degrees ). The unit cell content W(30)C(2)X(68) accommodates five hexanuclear tungsten clusters, similar by a total of three octahedral [W(6)X(8)] type clusters and two carbon-centered trigonal prismatic [W(6)CX(12)] type clusters, sharing terminal halogen atoms to form a network structure. The trigonal prismatic cluster compound W(6)CCl(15) (P2(1)/c, Z = 4; a = 9.8830(4) A, b = 11.8945(4) A, c = 17.8670(7) A, beta = 107.883(2) degrees ) is related to the already known compound W(6)CCl(16). According to X-ray powder structure refinement, the structure is showing a special connectivity pattern with short intercluster W-W contacts between trigonal prismatic cluster units.

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2: Nutrition research and practice, 2008 Summer, 2(2)
Chemokine Lkn-1/CCL15 enhances matrix metalloproteinase-9 release from human macrophages and macrophage-derived foam cells.

[Abstract]Atherosclerosis is characterized by a chronic inflammatory disease, and chemokines play an important role in both initiation and progression of atherosclerosis development. Leukotactin-1 (Lkn-1/CCL15), a new member of the human CC chemokine family, is a potent chemoattractant for leukocytes. Our previous study has demonstrated that Lkn-1/CCL15 plays a role in the initiation of atherosclerosis, however, little is currently known whether Lkn-1/CCL15 is associated with the progression of atherosclerosis. Matrix metalloproteinases (MMPs) in human coronary atherosclerotic lesions play a crucial role in the progression of atherosclerosis by altering the vulnerability of plaque rupture. In the present study, we examined whether Lkn-1/CCL15 modulates MMP-9 release, which is a prevalent form expressed by activated macrophages and foam cells. Human THP-1 monocytic cells and/or human peripheral blood monocytes (PBMC) were treated with phorbol myristate acetate to induce their differentiation into macrophages. Foam cells were prepared by the treatment of THP-1 macrophages with human oxidized LDL. The macrophages and foam cells were treated with Lkn-1/CCL15, and the levels of MMP-9 release were measured by Gelatin Zymography. Lkn-1/CCL15 significantly enhanced the levels of MMP-9 protein secretion from THP-1 monocytic cells-derived macrophages, human PBMC-derived macrophages, as well as macrophage-derived foam cell in a dose dependent manner. Our data suggest that the action of Lkn-1/CCL15 on macrophages and foam cells to release MMP-9 may contribute to plaque destabilization in the progression of atherosclerosis.

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3: Molecular biology reports, 2009 Aug 11,
Leukotactin-1/CCL15 induces cell migration and differentiation of human eosinophilic leukemia EoL-1 cells through PKCdelta activation.

[Abstract]Leukotactin-1 (Lkn-1)/CCL15 is a CC chemokine that binds to the CCR1 and CCR3. Lkn-1 functions as an essential factor in the migration of monocytes, lymphocytes, and neutrophils. Although eosinophils express both receptors, the role of Lkn-1 in immature eosinophils remains to be elucidated. In this present study, we investigated the contribution of the CCR1-binding chemokines to chemotactic activity and in the differentiation in the human eosinophilic leukemia cell line EoL-1. Lkn-1 induced the stronger migration of EoL-1 cells than other CCR1-binding chemokines such as RANTES/CCL5, MIP-1alpha/CCL3 and HCC-4/CCL16. Lkn-1-induced chemotaxis was inhibited by pertussis toxin, an inhibitor of G(i)/G(o) protein; U73122, an inhibitor of phospholipase C and rottlerin, an inhibitor of protein kinase C delta (PKCdelta). Lkn-1 increased PKCdelta activity, which was partially blocked by the pertussis toxin and U73122. Lkn-1 enhanced the butyric acid-induced differentiation via PKCdelta after binding to the increased CCR1 because Lkn-1 caused EoL-1 cells to change morphologically into mature eosinophil-like cells. Likewise, Lkn-1 increased the expression of both eosinophil peroxidase (EPO) and the major basic protein (MBP). PKCdelta activation due to Lkn-1 is involved in migration, as well as the butyric acid-induced differentiation. This finding contributes to an understanding of CC chemokines in eosinophil biology and to the development of novel therapies for the treatment of eosinophilic disorders. This study suggests the pivotal roles of Lkn-1 in the regulation of the movement and development of eosinophils.

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4: Biochemical and biophysical research communications, 2006 Jul 14, 345(4)
Increase of expression and activation of chemokine CCL15 in chronic renal failure.

[Abstract]Chemokines are believed to be involved in the pathogenesis of chronic renal failure (CRF). In CRF, significantly increased CCL15-IR plasma concentrations were detected. Whereas in plasma of healthy individuals one predominant CCL15-IR molecule with a M(w) of 15kDa [high molecular weight (HMW-CCL15-IR)] was identified, CRF plasma contains increased concentrations of truncated CCL15-IR molecules [intermediate molecular weight (IMW-CCL15-IR)]. HMW-CCL15-IR isolated from hemofiltrate revealed an M(w) of 10141.3, corresponding to deglycosylated CCL15(1-92) carrying a N-terminal pyrrolidone carboxylic acid. CCL15(12-92) was identified as a major component of IMW-CCL15-IR in CRF plasma. Compared to CCL15(1-92), in monocytes CCL15(12-92) causes stronger induction of intracellular calcium flux, chemotactic activity, and adhesion to fibronectin. Intracellular calcium flux assays revealed that, in comparison to peripheral blood mononuclear cells (PBMC) of healthy donors, PBMCs of CRF patients demonstrated an increased sensitivity to CCL15. Our results point to an involvement of the CCL15-CCR1 axis in the pathophysiology of CRF.

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5: Biochimica et biophysica acta, 2005 Dec 30, 1732(1-3)
Transcriptional regulation of human CC chemokine CCL15 gene by NF-kappaB and AP-1 elements in PMA-stimulated U937 monocytoid cells.

[Abstract]CCL15 exerts biological effects on a variety of cells, including monocytes. NF-kappaB has been reported to be involved in the transcription of the CCL15 gene. In this study, we have identified an AP-1 element located at -76/-65, which appears to regulate the transcription of the CCL15 gene. We also confirmed that the AP-1 factor binds to the element. Specific inhibitors for MAPK pathways and expression of dominant negative MKK4 or JNK1 reduced PMA-induced transcriptional activation of CCL15. Our findings indicate that transcription of the CCL15 gene is regulated by AP-1 and NF-kappaB through MEK and JNK MAPK pathways in monocytoid cells.

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6: Journal of immunology (Baltimore, Md. : 1950), 2005 Aug 1, 175(3)
Quantum proteolytic activation of chemokine CCL15 by neutrophil granulocytes modulates mononuclear cell adhesiveness.

[Abstract]Monocyte infiltration into inflammatory sites is generally preceded by neutrophils. We show here that neutrophils may support this process by activation of CCL15, a human chemokine circulating in blood plasma. Neutrophils were found to release CCL15 proteolytic activity in the course of hemofiltration of blood from renal insufficiency patients. Processing of CCL15 immunoreactivity (IR) in the pericellular space is suggested by a lack of proteolytic activity in blood and blood filtrate, but a shift of the retention time (t(R)) of CCL15-IR, detected by chromatographic separation of CCL15-IR in blood and hemofiltrate. CCL15 molecules with N-terminal deletions of 23 (delta23) and 26 (delta26) aa were identified as main proteolytic products in hemofiltrate. Neutrophil cathepsin G was identified as the principal protease to produce delta23 and delta26 CCL15. Also, elastase displays CCL15 proteolytic activity and produces a delta21 isoform. Compared with full-length CCL15, delta23 and delta26 isoforms displayed a significantly increased potency to induce calcium fluxes and chemotactic activity on monocytes and to induce adhesiveness of mononuclear cells to fibronectin. Thus, our findings indicate that activation of monocytes by neutrophils is at least in part induced by quantum proteolytic processing of circulating or endothelium-bound CCL15 by neutrophil cathepsin G.

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7: FEBS letters, 2004 Jul 16, 570(1-3)
Angiogenic activity of human CC chemokine CCL15 in vitro and in vivo.

[Abstract]CCL15 is a novel human CC chemokine and exerts its biological activities on immune cells through CCR1 and CCR3. Because a number of chemokines induce angiogenesis and endothelial cells express CCR1 and CCR3, we investigated the angiogenic activity of CCL15. Both CCL15(1-92) and N-terminal truncated CCL15(25-92) stimulate the chemotactic endothelial cell migration and differentiation, but CCL15(25-92) is at least 100-fold more potent than CCL15(1-92). Treatment with pertussis toxin (PTX), with anti-CCR1, or with anti-CCR3 antibody inhibits the CCL15(25-92)-induced endothelial cell migration. CCL15(25-92) also stimulates sprouting of vessels from aortic rings and mediates angiogenesis in the chick chorioallantoic membrane assay. Our findings demonstrate that CCL15(25-92) has in vitro and in vivo angiogenic activity, and suggest roles of the chemokine in angiogenesis.

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8: Molecules and cells, 2004 Apr 30, 17(2)
Involvement of two NF-kappaB binding sites in PMA-induced expression of the human leukotactin-1/CCL15 gene in U937 monocytoid cells.

[Abstract]Leukotactin-1 (Lkn-1)/CCL15, is a recently cloned chemotactic chemokine that appears to play important roles in the inflammatory process by recruiting immune cells to inflammatory sites. Expression of the Lkn-1/CCL15 gene is inducible in monocytes but its transcriptional regulation has not been studied. To identify Lkn-1/CCL15 regulatory sequences in monocytic cells, U937 cells were transiently transfected with the luciferase reporter gene linked to various deletions of the Lkn-1/CCL15 promoter region. The region -269 to -43 bp from the transcription start site proved to be important for induction by PMA. This region contained two potential NF-kappaB sites: one between -191 and -182 bp, and the other between -60 and -51 bp. Mutation of either element reduced PMA-induced expression and electrophoretic mobility shift assays revealed that NF-kappaB recognized both potential NF-kappaB sites. In addition, PMA-induction of Lkn-1/CCL15 in transiently transfected U937 cells was blocked by proteasome inhibitor 1. These observations demonstrate that the two NF-kappaB binding sites are essential for PMA-induced Lkn-1/CCL15 expression in human monocytes.

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9: The journal of peptide research : official journal of the American Peptide Society, 2004 Jan, 63(1)
Functional analysis of chemically synthesized derivatives of the human CC chemokine CCL15/HCC-2, a high affinity CCR1 ligand.

[Abstract]The CCL15 is a human CC chemokine that activates the receptors, CCR1 and CCR3. Unlike other chemokines, it contains an unusually long N-terminal domain of 31 amino acids preceding the first cysteine residue and a third disulfide bond. To elucidate the functional role of distinct structural determinants, a series of sequential amino-terminal truncated and point-mutated CCL15 derivatives as well as mutants lacking the third disulfide bond and the carboxy-terminal alpha-helix were synthesized using 9-fluorenylmethoxycarbonyl (Fmoc) chemistry. We demonstrate that a truncation of 24 amino acid residues (delta24-CCL15) converts the slightly active 92-residue delta0-CCL15 into a potent agonist of CC chemokine receptor 1 (CCR1) and a weak agonist of CCR3 in cell-based assays. The biological activity decreases from delta24-CCL15 to delta29-CCL15, and re-increases from delta29-CCL15 to delta30-CCL15. Thus, an exocyclic N-terminal region of only one amino acid residue is sufficient for efficient CCR1 activation. As none of the peptides investigated except for delta24-CCL15 activates CCR3, we suggest that CCR1 is the major receptor for CCL15 in vivo. Further we demonstrate that the third disulfide bond of CCL15 and an exchange of tyrosine in position 70 by a leucine residue, which is conserved in CXC chemokines, do not alter the interaction with CCR1. In contrast, a CCL15 derivative lacking the carboxy-terminal alpha-helix exhibits a complete loss of tertiary structure and hence loss of CCR1 agonistic and binding activity. This study demonstrates that specific protein residues in chemokines, which contribute to receptor-ligand interaction, vary significantly between chemokines and cannot be extrapolated using data from functionally related chemokines.

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10: FEBS letters, 2002 Mar 27, 515(1-3)
Leukotactin-1/CCL15-induced chemotaxis signaling through CCR1 in HOS cells.

[Abstract]Leukotactin-1 (Lkn-1)/CCL15 is a recently cloned CC-chemokine that binds to the CCR1 and CCR3. Although Lkn-1 has been known to function as a chemoattractant for neutrophils, monocytes and lymphocytes, its cellular mechanism remains unclear. To understand the mechanism of Lkn-1-induced chemotaxis signaling, we examined the chemotactic activities of human osteogenic sarcoma cells expressing CCR1 in response to Lkn-1 using inhibitors of signaling molecules. Inhibitors of G(i)/G(o) protein, phospholipase C (PLC) and protein kinase Cdelta (PKCdelta) inhibited the chemotactic activity of Lkn-1 indicating that Lkn-1-induced chemotaxis signal is transduced through G(i)/G(o) protein, PLC and PKCdelta. The activities of PLC and PKCdelta were also enhanced by Lkn-1 stimulation. Chemotactic activity of Lkn-1 was inhibited by the treatment of cycloheximide and actinomycin D suggesting that newly synthesized proteins are needed for chemotaxis. Nuclear factor-kappaB (NF-kappaB) inhibitor reduced chemotactic activity of Lkn-1. DNA binding activity of NF-kappaB was also enhanced by Lkn-1 stimulation. These results suggest that Lkn-1 transduces the signal through G(i)/G(o) protein, PLC, PKCdelta, NF-kappaB and newly synthesized proteins for chemotaxis.

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11: Journal of leukocyte biology, 2001 Sep, 70(3)
Hemofiltrate CC chemokines with unique biochemical properties: HCC-1/CCL14a and HCC-2/CCL15.

[Abstract]The hemofiltrate CC chemokines CCL14a (formerly HCC-1), CCL14b (formerly HCC-3), and CCL15 (formerly HCC-2) are encoded by mono- as well as bicistronic transcripts from a tandem gene arrangement on human chromosome 17q11.2. The transcription and splicing into several mono- and bicistronic transcripts of this gene complex are unique for human genes. No corresponding mechanism is known in nonprimate mammalian species such as mice and rats. The extremely high concentration of CCL14a in human plasma is exceptional for chemokines and led to the identification of this chemokine. Several molecular forms of CCL14a have been isolated and investigated. The mature propeptide CCL14a(1-74) is a low-affinity agonist of CCR1 which is converted to a high-affinity agonist of CCR1 and CCR5 on proteolytic processing by serine proteases. In contrast, CCL15 is characterized using molecular forms deduced from the mRNA/cDNA and shown to activate cells via CCR1 and CCR3, also dependent on the amino-terminal length. Hemofiltrate CC chemokines are chemoattractants for different types of leukocytes including monocytes, eosinophils, T cells, dendritic cells, and neutrophils. In this review, we emphasize the genomic organization, expression patterns, and biochemical properties of CCL14a, CCL14b, and CCL15. We report results of significance for the development of therapeutic strategies, especially concerning HIV infection and inflammatory diseases.